WorldWideScience

Sample records for high duty cycles

  1. Performance concerns for high duty fuel cycle

    International Nuclear Information System (INIS)

    Esposito, V.J.; Gutierrez, J.E.

    1999-01-01

    One of the goals of the nuclear industry is to achieve economic performance such that nuclear power plants are competitive in a de-regulated market. The manner in which nuclear fuel is designed and operated lies at the heart of economic viability. In this sense reliability, operating flexibility and low costs are the three major requirements of the NPP today. The translation of these three requirements to the design is part of our work. The challenge today is to produce a fuel design which will operate with long operating cycles, high discharge burnup, power up-rating and while still maintaining all design and safety margins. European Fuel Group (EFG) understands that to achieve the required performance high duty/energy fuel designs are needed. The concerns for high duty design includes, among other items, core design methods, advanced Safety Analysis methodologies, performance models, advanced material and operational strategies. The operational aspects require the trade-off and evaluation of various parameters including coolant chemistry control, material corrosion, boiling duty, boron level impacts, etc. In this environment MAEF is the design that EFG is now offering based on ZIRLO alloy and a robust skeleton. This new design is able to achieve 70 GWd/tU and Lead Test Programs are being executed to demonstrate this capability. A number of performance issues which have been a concern with current designs have been resolved such as cladding corrosion and incomplete RCCA insertion (IRI). As the core duty becomes more aggressive other new issues need to be addressed such as Axial Offset Anomaly. These new issues are being addressed by combination of the new design in concert with advanced methodologies to meet the demanding needs of NPP. The ability and strategy to meet high duty core requirements, flexibility of operation and maintain acceptable balance of all technical issues is the discussion in this paper. (authors)

  2. Evolution of high duty cycle echolocation in bats

    DEFF Research Database (Denmark)

    Fenton, M. B.; Faure, P. A.; Ratcliffe, J. M.

    2012-01-01

    Duty cycle describes the relative 'on time' of a periodic signal. In bats, we argue that high duty cycle (HDC) echolocation was selected for and evolved from low duty cycle (LDC) echolocation because increasing call duty cycle enhanced the ability of echolocating bats to detect, lock onto and track...... relative to background objects and their prey. HDC echolocators are particularly sensitive to amplitude and frequency glints generated by the wings of fluttering insects. We hypothesize that narrowband/CF calls produced at high duty cycle, and combined with neurobiological specializations for processing....... In contrast, bats using HDC echolocation emit long duration, narrowband calls dominated by a single constant frequency (CF) separated by relatively short periods of silence. HDC bats separate pulse and echo in frequency by exploiting information contained in Doppler-shifted echoes arising from their movements...

  3. High duty cycle to low duty cycle: echolocation behaviour of the hipposiderid bat Coelops frithii.

    Science.gov (United States)

    Ho, Ying-Yi; Fang, Yin-Ping; Chou, Cheng-Han; Cheng, Hsi-Chi; Chang, Hsueh-Wen

    2013-01-01

    Laryngeally echolocating bats avoid self-deafening (forward masking) by separating pulse and echo either in time using low duty cycle (LDC) echolocation, or in frequency using high duty cycle (HDC) echolocation. HDC echolocators are specialized to detect fluttering targets in cluttered environments. HDC echolocation is found only in the families Rhinolophidae and Hipposideridae in the Old World and in the New World mormoopid, Pteronotus parnellii. Here we report that the hipposiderid Coelops frithii, ostensibly an HDC bat, consistently uses an LDC echolocation strategy whether roosting, flying, or approaching a fluttering target rotating at 50 to 80 Hz. We recorded the echolocation calls of free-flying C. frithii in the field in various situations, including presenting bats with a mechanical fluttering target. The echolocation calls of C. frithii consisted of an initial narrowband component (0.5±0.3 ms, 90.6±2.0 kHz) followed immediately by a frequency modulated (FM) sweep (194 to 113 kHz). This species emitted echolocation calls at duty cycles averaging 7.7±2.8% (n = 87 sequences). Coelops frithii approached fluttering targets more frequently than did LDC bats (C.frithii, approach frequency  = 40.4%, n = 80; Myotis spp., approach frequency  = 0%, n = 13), and at the same frequency as sympatrically feeding HDC species (Hipposideros armiger, approach rate  = 53.3%, n = 15; Rhinolophus monoceros, approach rate  = 56.7%, n = 97). We propose that the LDC echolocation strategy used by C. frithii is derived from HDC ancestors, that this species adjusts the harmonic contents of its echolocation calls, and that it may use both the narrowband component and the FM sweep of echolocations calls to detect fluttering targets.

  4. High duty cycle to low duty cycle: echolocation behaviour of the hipposiderid bat Coelops frithii.

    Directory of Open Access Journals (Sweden)

    Ying-Yi Ho

    Full Text Available Laryngeally echolocating bats avoid self-deafening (forward masking by separating pulse and echo either in time using low duty cycle (LDC echolocation, or in frequency using high duty cycle (HDC echolocation. HDC echolocators are specialized to detect fluttering targets in cluttered environments. HDC echolocation is found only in the families Rhinolophidae and Hipposideridae in the Old World and in the New World mormoopid, Pteronotus parnellii. Here we report that the hipposiderid Coelops frithii, ostensibly an HDC bat, consistently uses an LDC echolocation strategy whether roosting, flying, or approaching a fluttering target rotating at 50 to 80 Hz. We recorded the echolocation calls of free-flying C. frithii in the field in various situations, including presenting bats with a mechanical fluttering target. The echolocation calls of C. frithii consisted of an initial narrowband component (0.5±0.3 ms, 90.6±2.0 kHz followed immediately by a frequency modulated (FM sweep (194 to 113 kHz. This species emitted echolocation calls at duty cycles averaging 7.7±2.8% (n = 87 sequences. Coelops frithii approached fluttering targets more frequently than did LDC bats (C.frithii, approach frequency  = 40.4%, n = 80; Myotis spp., approach frequency  = 0%, n = 13, and at the same frequency as sympatrically feeding HDC species (Hipposideros armiger, approach rate  = 53.3%, n = 15; Rhinolophus monoceros, approach rate  = 56.7%, n = 97. We propose that the LDC echolocation strategy used by C. frithii is derived from HDC ancestors, that this species adjusts the harmonic contents of its echolocation calls, and that it may use both the narrowband component and the FM sweep of echolocations calls to detect fluttering targets.

  5. Development of 700 pps high-duty-cycle line-type pulse modulator

    Energy Technology Data Exchange (ETDEWEB)

    Baba, H.; Satoh, K.; Miura, A. [NIHON KOSHUHA Co., LTD., Yokohama, Kanagawa (Japan)] [and others

    1997-04-01

    The high-duty-cycle line-type pulse modulator has been developed to drive the 5.5 MW S-band klystron at the 700 pps maximum repetition-rate and the 14 {mu}sec flat-top pulse-width. To keep an enough recovery time to the thyratron-tube, the command charging scheme was adopted. To do this, a charging SCR-bank has been developed, which is capable of handling the peak charging current of 50 A. The system achieved the world wide highest average output-power of 205 kW. Two modulators have been installed in a new high-duty-cycle electron linear accelerator, which has been started its business operation in March 1996 as an electron-beam-sterilization facility. (J.P.N)

  6. A New High Frequency Injection Method Based on Duty Cycle Shifting without Maximum Voltage Magnitude Loss

    DEFF Research Database (Denmark)

    Wang, Dong; Lu, Kaiyuan; Rasmussen, Peter Omand

    2015-01-01

    The conventional high frequency signal injection method is to superimpose a high frequency voltage signal to the commanded stator voltage before space vector modulation. Therefore, the magnitude of the voltage used for machine torque production is limited. In this paper, a new high frequency...... amplitude. This may be utilized to develop new position estimation algorithm without involving the inductance in the medium to high speed range. As an application example, a developed inductance independent position estimation algorithm using the proposed high frequency injection method is applied to drive...... injection method, in which high frequency signal is generated by shifting the duty cycle between two neighboring switching periods, is proposed. This method allows injecting a high frequency signal at half of the switching frequency without the necessity to sacrifice the machine fundamental voltage...

  7. EPA Nonregulatory Nonroad Duty Cycles

    Science.gov (United States)

    EPA nonregulatory, nonroad duty cycles for equipment such as agricultural tractors, backhoe loaders,crawlers tractors, excavators, arc welding skid steer loaders, and wheel loaders. Also,test procedures, laboratory methods, and emissions for this equipmen

  8. 40 CFR 94.105 - Duty cycles.

    Science.gov (United States)

    2010-07-01

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

  9. Coherent lidar modulated with frequency stepped pulse trains for unambiguous high duty cycle range and velocity sensing in the atmosphere

    DEFF Research Database (Denmark)

    Lindelöw, Per Jonas Petter; Mohr, Johan Jacob

    2007-01-01

    Range unambiguous high duty cycle coherent lidars can be constructed based on frequency stepped pulse train modulation, even continuously emitting systems could be envisioned. Such systems are suitable for velocity sensing of dispersed targets, like the atmosphere, at fast acquisition rates....... The lightwave synthesized frequency sweeper is a suitable generator yielding fast pulse repetition rates and stable equidistant frequency steps. Theoretical range resolution profiles of modulated lidars are presented....

  10. Design of a high-efficiency seven-port beam splitter using a dual duty cycle grating structure.

    Science.gov (United States)

    Wen, Fung Jacky; Chung, Po Sheun

    2011-07-01

    In this paper, we propose a compact seven-port beam splitter which is constructed using only a single-layer high-density grating with a dual duty cycle structure. The properties of this grating are investigated by a simplified modal method. The diffraction efficiency can be achieved around 10% more than conventional Dammann gratings while the uniformity can still be maintained at less than 1%. The effect of deviations from the design parameters on the performance of the grating is also presented.

  11. A high-performance gradient insert for rapid and short-T2 imaging at full duty cycle.

    Science.gov (United States)

    Weiger, Markus; Overweg, Johan; Rösler, Manuela Barbara; Froidevaux, Romain; Hennel, Franciszek; Wilm, Bertram Jakob; Penn, Alexander; Sturzenegger, Urs; Schuth, Wout; Mathlener, Menno; Borgo, Martino; Börnert, Peter; Leussler, Christoph; Luechinger, Roger; Dietrich, Benjamin Emanuel; Reber, Jonas; Brunner, David Otto; Schmid, Thomas; Vionnet, Laetitia; Pruessmann, Klaas P

    2018-06-01

    The goal of this study was to devise a gradient system for MRI in humans that reconciles cutting-edge gradient strength with rapid switching and brings up the duty cycle to 100% at full continuous amplitude. Aiming to advance neuroimaging and short-T 2 techniques, the hardware design focused on the head and the extremities as target anatomies. A boundary element method with minimization of power dissipation and stored magnetic energy was used to design anatomy-targeted gradient coils with maximally relaxed geometry constraints. The design relies on hollow conductors for high-performance cooling and split coils to enable dual-mode gradient amplifier operation. With this approach, strength and slew rate specifications of either 100 mT/m with 1200 mT/m/ms or 200 mT/m with 600 mT/m/ms were reached at 100% duty cycle, assuming a standard gradient amplifier and cooling unit. After manufacturing, the specified values for maximum gradient strength, maximum switching rate, and field geometry were verified experimentally. In temperature measurements, maximum local values of 63°C were observed, confirming that the device can be operated continuously at full amplitude. Testing for peripheral nerve stimulation showed nearly unrestricted applicability in humans at full gradient performance. In measurements of acoustic noise, a maximum average sound pressure level of 132 dB(A) was determined. In vivo capability was demonstrated by head and knee imaging. Full gradient performance was employed with echo planar and zero echo time readouts. Combining extreme gradient strength and switching speed without duty cycle limitations, the described system offers unprecedented options for rapid and short-T 2 imaging. Magn Reson Med 79:3256-3266, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  12. Automatic control of clock duty cycle

    Science.gov (United States)

    Feng, Xiaoxin (Inventor); Roper, Weston (Inventor); Seefeldt, James D. (Inventor)

    2010-01-01

    In general, this disclosure is directed to a duty cycle correction (DCC) circuit that adjusts a falling edge of a clock signal to achieve a desired duty cycle. In some examples, the DCC circuit may generate a pulse in response to a falling edge of an input clock signal, delay the pulse based on a control voltage, adjust the falling edge of the input clock signal based on the delayed pulse to produce an output clock signal, and adjust the control voltage based on the difference between a duty cycle of the output clock signal and a desired duty cycle. Since the DCC circuit adjusts the falling edge of the clock cycle to achieve a desired duty cycle, the DCC may be incorporated into existing PLL control loops that adjust the rising edge of a clock signal without interfering with the operation of such PLL control loops.

  13. Novel packaging for CW and QCW diode laser modules for operation with high power and duty cycles

    Science.gov (United States)

    Fassbender, Wilhelm; Lotz, Jens; Kissel, Heiko; Biesenbach, Jens

    2018-02-01

    Continuous wave (CW) and quasi-continuous wave (QCW) operated diode laser bars and arrays have found a wide range of industrial, medical, scientific, military and space applications with a broad variety in wavelength, pulse energy, pulse duration and beam quality. Recent applications require even higher power, duty cycles and power density. The heat loss will be dissipated by conductive cooling or liquid cooling close to the bars. We present the latest performance and reliability data of two novel high-brightness CW and QCW arrays of customized and mass-production modules, in compact and robust industry design for operation with high power and high duty cycles. All designs are based on single diode packages consisting of 10mm laser bars, soft or hard soldered between expansion matched submounts. The modular components cover a wide span of designs which differ basically in water/conduction (active/passive) cooled, single, linear (horizontal and vertical) arranged designs, as well as housed and unhoused modules. The different assembling technologies of active and passive cooled base plates affect the heat dissipation and therefore the reachable power at different QCW operating conditions, as well as the lifetime. As an example, a package consisting of 8 laser diodes, connected to a 28.8*13.5*7.0mm3 DCB (direct copper bonded) submount, passively or actively cooled is considered. This design is of particular interest for mobile applications seamless module to module building system, with an infinite number of laser bars at 1.7mm pitch. Using 940nm bars we can reach an optical output power per bar of 450W at 25°C base plate temperature with 10Hz, 1.2% duty cycle and 1.2ms pulse duration. As an additional example, micro channel coolers can be vertically stacked up to 50 diodes with a 1,15mm pitch. This design is suitable for all applications, demanding also compactness and light weight and high power density. Using near infrared bars and others, we can reach an optical

  14. Diversification and reproductive isolation: cryptic species in the only New World high-duty cycle bat, Pteronotus parnellii

    Directory of Open Access Journals (Sweden)

    Clare Elizabeth L

    2013-01-01

    Full Text Available Abstract Background Molecular techniques are increasingly employed to recognize the presence of cryptic species, even among commonly observed taxa. Previous studies have demonstrated that bats using high-duty cycle echolocation may be more likely to speciate quickly. Pteronotus parnellii is a widespread Neotropical bat and the only New World species to use high-duty cycle echolocation, a trait otherwise restricted to Old World taxa. Here we analyze morphological and acoustic variation and genetic divergence at the mitochondrial COI gene, the 7th intron region of the y-linked Dby gene and the nuclear recombination-activating gene 2, and provide extensive evidence that P. parnellii is actually a cryptic species complex. Results Central American populations form a single species while three additional species exist in northern South America: one in Venezuela, Trinidad and western Guyana and two occupying sympatric ranges in Guyana and Suriname. Reproductive isolation appears nearly complete (only one potential hybrid individual found. The complex likely arose within the last ~6 million years with all taxa diverging quickly within the last ~1-2 million years, following a pattern consistent with the geological history of Central and northern South America. Significant variation in cranial measures and forearm length exists between three of the four groups, although no individual morphological character can discriminate these in the field. Acoustic analysis reveals small differences (5–10 kHz in echolocation calls between allopatric cryptic taxa that are unlikely to provide access to different prey resources but are consistent with divergence by drift in allopatric species or through selection for social recognition. Conclusions This unique approach, considering morphological, acoustic and multi-locus genetic information inherited maternally, paternally and bi-parentally, provides strong support to conclusions about the cessation of gene flow and

  15. 40 CFR 1033.530 - Duty cycles and calculations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty cycles and calculations. 1033.530... CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test Procedures § 1033.530 Duty cycles and calculations. This section describes how to apply the duty cycle to measured emission rates to calculate cycle...

  16. Progress in high duty cycle, highly efficient fiber coupled 940-nm pump modules for high-energy class solid-state lasers

    Science.gov (United States)

    Platz, R.; Frevert, C.; Eppich, B.; Rieprich, J.; Ginolas, A.; Kreutzmann, S.; Knigge, S.; Erbert, G.; Crump, P.

    2018-03-01

    Diode lasers pump sources for future high-energy-class laser systems based on Yb-doped solid state amplifiers must deliver high optical intensities, high conversion efficiency (ηE = > 50%) at high repetition rates (f = 100 Hz) and long pulse widths (τ = 0.5…2 ms). Over the last decade, a series of pump modules has been developed at the Ferdinand-BraunInstitut to address these needs. The latest modules use novel wide-aperture single emitter diode lasers in passively side cooled stacks, operate at τ = 1 ms, f = 100…200 Hz and deliver 5…6 kW optical output power from a fiber with 1.9 mm core diameter and NA of 0.22, for spatial brightness BΩ > 1 MW/cm2 sr. The performance to date and latest developments in these high brightness modules are summarized here with recent work focusing on extending operation to other pumping conditions, as needed for alternative solid state laser designs. Specifically, the electro-optic, spectral and beam propagation characteristics of the module and its components are studied as a function of τ for a fixed duty cycle DC = 10% for τ = 1...100 ms, and first data is shown for continuous wave operation. Clear potential is seen to fulfill more demanding specifications without design changes. For example, high power long-pulse operation is demonstrated, with a power of > 5 kW at τ = 100 ms. Higher brightness operation is also confirmed at DC = 10% and τ = 1 ms, with > 5 kW delivered in a beam with BΩ > 4 MW/cm2 sr.

  17. Electrofishing power requirements in relation to duty cycle

    Science.gov (United States)

    Miranda, L.E.; Dolan, C.R.

    2004-01-01

    Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

  18. 46 CFR 111.25-15 - Duty cycle.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Duty cycle. 111.25-15 Section 111.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-15 Duty cycle. Each motor must be rated for continuous duty, except a motor for an...

  19. 40 CFR 1065.514 - Cycle-validation criteria for operation over specified duty cycles.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Cycle-validation criteria for operation over specified duty cycles. 1065.514 Section 1065.514 Protection of Environment ENVIRONMENTAL... Over Specified Duty Cycles § 1065.514 Cycle-validation criteria for operation over specified duty...

  20. Wi-Fi Coexistence with Duty Cycled LTE-U

    Directory of Open Access Journals (Sweden)

    Yimin Pang

    2017-01-01

    Full Text Available Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U technologies has drawn significant concern in industry. In this paper, we investigate the Wi-Fi performance in the presence of duty cycle based LTE-U transmission on the same channel. More specifically, one LTE-U cell and one Wi-Fi basic service set (BSS coexist by allowing LTE-U devices to transmit their signals only in predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend the shared channel using the distributed coordination function (DCF protocol without cooperation with the LTE-U system or prior knowledge about the duty cycle period or duty cycle of LTE-U transmission. We define the fairness of the above scheme as the difference between Wi-Fi performance loss ratio (considering a defined reference performance and the LTE-U duty cycle (or function of LTE-U duty cycle. Depending on the interference to noise ratio (INR being above or below −62 dbm, we classify the LTE-U interference as strong or weak and establish mathematical models accordingly. The average throughput and average service time of Wi-Fi are both formulated as functions of Wi-Fi and LTE-U system parameters using probability theory. Lastly, we use the Monte Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing.

  1. Laterally coupled distributed feedback lasers emitting at 2 μm with quantum dash active region and high-duty-cycle etched semiconductor gratings

    Science.gov (United States)

    Papatryfonos, Konstantinos; Saladukha, Dzianis; Merghem, Kamel; Joshi, Siddharth; Lelarge, Francois; Bouchoule, Sophie; Kazazis, Dimitrios; Guilet, Stephane; Le Gratiet, Luc; Ochalski, Tomasz J.; Huyet, Guillaume; Martinez, Anthony; Ramdane, Abderrahim

    2017-02-01

    Single-mode diode lasers on an InP(001) substrate have been developed using InAs/In0.53Ga0.47As quantum dash (Qdash) active regions and etched lateral Bragg gratings. The lasers have been designed to operate at wavelengths near 2 μm and exhibit a threshold current of 65 mA for a 600 μm long cavity, and a room temperature continuous wave output power per facet >5 mW. Using our novel growth approach based on the low ternary In0.53Ga0.47As barriers, we also demonstrate ridge-waveguide lasers emitting up to 2.1 μm and underline the possibilities for further pushing the emission wavelength out towards longer wavelengths with this material system. By introducing experimentally the concept of high-duty-cycle lateral Bragg gratings, a side mode suppression ratio of >37 dB has been achieved, owing to an appreciably increased grating coupling coefficient of κ ˜ 40 cm-1. These laterally coupled distributed feedback (LC-DFB) lasers combine the advantage of high and well-controlled coupling coefficients achieved in conventional DFB lasers, with the regrowth-free fabrication process of lateral gratings, and exhibit substantially lower optical losses compared to the conventional metal-based LC-DFB lasers.

  2. Analysis and design of a high-linearity receiver RF front-end with an improved 25%-duty-cycle LO generator for WCDMA/GSM applications

    International Nuclear Information System (INIS)

    Hu Song; Li Weinan; Huang Yumei; Hong Zhiliang

    2012-01-01

    A fully integrated receiver RF front-end that meets WCDMA/GSM system requirements is presented. It supports SAW-less operation for WCDMA. To improve the linearity in terms of both IP3 and IP2, the RF front-end is comprised of multiple-gated LNAs with capacitive desensitization, current-mode passive mixers with the proposed IP2 calibration circuit and reconfigurable Tow-Thomas-like biquad TIAs. A new power-saving multi-mode divider with low phase noise is proposed to provide the 4-phase 25%-duty-cycle LO. In addition, a constant-g m biasing with a non-chip resistor is adopted to make the conversion gain invulnerable to the process and temperature variations of the transimpedance. This RF front-end is integrated in a receiver with an on-chip frequency synthesizer in 0.13 μm CMOS. The measurement results show that owing to this high-linearity RF front-end, the receiver achieves −6 dBm IIP3 and better than +60 dBm IIP2 for all modes and bands. (semiconductor integrated circuits)

  3. 40 CFR Appendix II to Part 1042 - Steady-State Duty Cycles

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Steady-State Duty Cycles II Appendix..., App. II Appendix II to Part 1042—Steady-State Duty Cycles (a) The following duty cycles apply as specified in § 1042.505(b)(1): (1) The following duty cycle applies for discrete-mode testing: E3 mode No...

  4. 40 CFR Appendix II to Part 1039 - Steady-State Duty Cycles

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Steady-State Duty Cycles II Appendix... Appendix II to Part 1039—Steady-State Duty Cycles (a) The following duty cycles apply for constant-speed engines: (1) The following duty cycle applies for discrete-mode testing: D2 mode number Engine speed...

  5. Medium- and Heavy-Duty Vehicle Duty Cycles for Electric Powertrains

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Kenneth; Bennion, Kevin; Miller, Eric; Prohaska, Bob

    2016-03-02

    NREL's Fleet Test and Evaluation group has extensive in-use vehicle data demonstrating the importance of understanding the vocational duty cycle for appropriate sizing of electric vehicle (EV) and power electronics components for medium- and heavy-duty EV applications. This presentation includes an overview of recent EV fleet evaluation projects that have valuable in-use data that can be leveraged for sub-system research, analysis, and validation. Peak power and power distribution data from in-field EVs are presented for four different vocations, including class 3 delivery vans, class 6 delivery trucks, class 8 transit buses, and class 8 port drayage trucks, demonstrating the impacts of duty cycle on performance requirements.

  6. 47 CFR 27.50 - Power limits and duty cycle.

    Science.gov (United States)

    2010-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.50 Power limits and duty cycle. (a) The.... In measuring transmissions in this band using an average power technique, the peak-to-average ratio (PAR) of the transmission may not exceed 13 dB. (6) Peak transmit power must be measured over any...

  7. 40 CFR 1065.512 - Duty cycle generation.

    Science.gov (United States)

    2010-07-01

    ... at least 5 Hz. Use these recorded values to calculate cycle-validation statistics and total work. (d... sequence of paired values for speed and torque or for speed and power. (b) Transform normalized values of... describes how to transform these normalized values into a sequence of reference speeds, f nref. Running duty...

  8. INFLUENCE OF RESIDENTIAL HVAC DUTY CYCLE ON INDOOR AIR QUALITY

    Science.gov (United States)

    Measurements of duty cycle, the fraction of time the heating and cooling (HVAC) system was operating, were made in homes during the spring season of the RTP Particulate Matter Panel Study and the Tampa Asthmatic Children's Study. A temperature sensor/logger placed on an outlet...

  9. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Science.gov (United States)

    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 by testing the engine on a dynamometer with one of the following transient duty cycles to determine...

  10. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the 2007 model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in...

  11. 40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty Cycles for Propulsion Marine... Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The following duty cycle applies for discrete-mode testing: E4 Mode No. Enginespeed 1 Torque(percent) 2...

  12. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Science.gov (United States)

    2010-07-01

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

  13. Vitreous flow rates through dual pneumatic cutters: effects of duty cycle and cut rate

    Directory of Open Access Journals (Sweden)

    Abulon DJK

    2015-02-01

    Full Text Available Dina Joy K Abulon Medical Affairs, Alcon Research, Ltd, Lake Forest, CA, USA Purpose: We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. Methods: The CONSTELLATION® Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT® vitrectomy probes of each diameter (25+®, 25, 23, and 20 gauge operated from 500 cuts per minute (cpm up to 5,000 cpm. Duty cycle modes tested included biased open, 50/50, and biased closed. Flow rates were calculated by assessing the change in weight of porcine eyes during vitreous aspiration. Volumetric flow rate was measured with a computer-connected electronic scale. Results: At lower cut rates, the biased open mode produced higher flow than did the 50/50 mode, which produced higher flow than did the biased closed mode. In the biased closed and 50/50 modes, vitreous flow rates tended to increase with increasing cut rate. Vitreous flow rates in the biased open duty cycle mode remained relatively constant across cut rates. Conclusion: Vitreous flow rates through dual pneumatic vitrectomy probes could be manipulated by changing the duty cycle modes on the vitrectomy system. Differences in duty cycle behavior suggest that high-speed cut rates of 5,000 cpm may optimize vitreous aspiration. Keywords: enhanced 25-gauge vitrectomy, 25-gauge vitrectomy, 20-gauge vitrectomy, 23-gauge vitrectomy, aspiration, Constellation Vision System

  14. Sensitivity study on Duty cycles for Actuator fatigue analysis

    OpenAIRE

    Jacamon, Pauline

    2016-01-01

    During the aircraft's ight, the control surfaces that enable the aircraft to perform the required maneuvers and the actuator that control them have to withstand loads. Those loads will a ect the actuators lifetime and that is why it is very important to be able to predict their amplitude in order to make sure the actuators will last long enough and be ecient enough during the aircraft lifetime. Duty cycles are thus computed in order to compute the actuators fatigue severity and endurance crit...

  15. Vehicle modeling and duty cycle analysis to validate technology feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Castonguay, S. [National Centre for Advanced Transportation, Saint-Jerome, PQ (Canada)

    2010-07-01

    The National Centre for Advanced Transportation (CNTA) is a non-profit organization with a board consisting of representatives from the transportation industry, public service and public transit organizations, research and teaching institutions, and from municipal and economic development organizations. The objectives of the CNTA are to accelerate the introduction of electric and hybrid vehicles; act as a catalyst in projects; assist in increasing Canadian technology assets; initiate and support electric vehicle conversion projects; increase Canadian business for electric vehicles, hybrid vehicles, and plug-in electric vehicles; and provide a cost-effective solution and aggressive payback for road/off-road vehicles. This presentation provided an overview of the objectives and services of the CNTA. It discussed various road and off-road vehicles, duty cycle and technology of electric vehicles. Specific topics related to the technology were discussed, including configuration; controls and interface; efficiency maps; models and simulation; validation; and support. figs.

  16. Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami Nathan [Eaton Corporation

    2017-06-30

    Nearly 30% of fuel energy is not utilized and wasted in the engine exhaust. Organic Rankine Cycle (ORC) based waste heat recovery (WHR) systems offer a promising approach on waste energy recovery and improving the efficiency of Heavy-Duty diesel engines. Major barriers in the ORC WHR system are the system cost and controversial waste heat recovery working fluids. More than 40% of the system cost is from the additional heat exchangers (recuperator, condenser and tail pipe boiler). The secondary working fluid loop designed in ORC system is either flammable or environmentally sensitive. The Eaton team investigated a novel approach to reduce the cost of implementing ORC based WHR systems to Heavy-Duty (HD) Diesel engines while utilizing safest working fluids. Affordable Rankine Cycle (ARC) concept aimed to define the next generation of waste energy recuperation with a cost optimized WHR system. ARC project used engine coolant as the working fluid. This approach reduced the need for a secondary working fluid circuit and subsequent complexity. A portion of the liquid phase engine coolant has been pressurized through a set of working fluid pumps and used to recover waste heat from the exhaust gas recirculation (EGR) and exhaust tail pipe exhaust energy. While absorbing heat, the mixture is partially vaporized but remains a wet binary mixture. The pressurized mixed-phase engine coolant mixture is then expanded through a fixed-volume ratio expander that is compatible with two-phase conditions. Heat rejection is accomplished through the engine radiator, avoiding the need for a separate condenser. The ARC system has been investigated for PACCAR’s MX-13 HD diesel engine.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lijuan; Duran, Adam; Gonder, Jeffrey; Kelly, Kenneth

    2015-10-13

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

  18. Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

    Energy Technology Data Exchange (ETDEWEB)

    Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth; Lammert, Michael

    2016-10-06

    In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using the k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.

  19. Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth; Lammert, Michael

    2016-08-01

    In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using the k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.

  20. Evaluation of duty cycles for heavy-duty urban vehicles : final report of IEA AMF Annex 29

    Energy Technology Data Exchange (ETDEWEB)

    Nylund, N.O.; Erkkila, K. [VTT Technical Research Centre of Finland, Espoo (Finland); Clark, N. [West Virginia Univ., Morgantown, WV (United States); Rideout, G. [Environment Canada, Ottawa, ON (Canada). Environmental Technology Centre, Emissions Research and Measurement Div

    2007-07-01

    Heavy-duty vehicles in Europe and North America will require incylinder measures or exhaust gas after-treatment technology to control emissions and meet ever stringent emission requirements. Alternatively, manufacturers can choose clean burning alternative fuels such as natural gas. Although there are no international standards for heavy-duty vehicle chassis dynamometer testing at present, the IEA Implementing Agreements offer excellent platforms for international collaborative research. Harmonization of test methods for vehicles and fuels is one important task. This paper reported on the work of 3 laboratories that have produced emission results for complete heavy-duty vehicles. VTT Technical Research of Finland, Environment Canada and West Virginia University measured standard size urban buses driving various duty cycles on chassis dynamometers. The number of transient test cycles per laboratory varied from 6 to 16. European and North American diesel and natural gas vehicles were included in the vehicle matrix. The objective was to demonstrate how the driving cycle affects the emission performance of conventional and advanced urban buses. Several driving cycles were run on urban buses to better understand the characteristics of different duty cycles; produce a key for cross-interpretation of emission results generated with different cycles; and study the interaction between vehicle, exhaust after-treatment and fuel technologies and test procedures. Fuel consumption and exhaust emissions were measured. The results varied significantly not only by test cycle, but also by vehicle technology. In general, vehicles emissions were directly proportioned to the amount of fuel consumed, with the exception of NOx-emissions from SCR-vehicles. There was a clear difference in the emission profiles of European and North American vehicles. In Europe, fuel efficiency was emphasized, while in North America, more focus was given to regulated exhaust emissions, especially low

  1. Fabrication of Sn–Ni/MWCNT composite coating for Li-ion batteries by pulse electrodeposition: Effects of duty cycle

    Energy Technology Data Exchange (ETDEWEB)

    Uysal, Mehmet, E-mail: mehmetu@sakarya.edu.tr; Cetinkaya, Tugrul; Alp, Ahmet; Akbulut, Hatem

    2015-04-15

    Highlights: • Sn–Ni/MWCNT composite electrodes prepared by pulse electrodeposition at different duty cycle. • The effect of duty cycle studied on electrochemical properties of composite electrodes. • A high reversible capacity, and good cyclability were achieved for Sn–Ni/MWNT (75% duty cycle). - Abstract: Nanocrystalline Sn–Ni/MWCNT composite was prepared by ultrasonic-pulse electrodeposition on a copper substrate in a pyrophosphate bath at different duty cycles. Surface morphology of produced Sn–Ni/MWCNT composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. X-ray diffraction analysis (XRD) was carried out to investigate structure of Sn–Ni/MWCNT composites. The electrochemical performance of Sn–Ni/MWCNT composite electrodes were investigated by charge/discharge tests and cyclic voltammetric experiments. The cells discharge capacities were determined by cyclic testing by a battery tester at a constant current in voltage range between 0.02 V and 1.5 V. The duty cycle was shown to be a crucial factor to improve Sn–Ni/MWCNT composite anodes for cyclability and reversible capacity.

  2. Performance of PZT stacks under high-field electric cycling at various temperatures in heavy-duty diesel engine fuel injectors

    Science.gov (United States)

    Wang, Hong; Lee, Sung-Min; Lin, Hua-Tay; Stafford, Randy

    2016-04-01

    Testing and characterization of large prototype lead zirconate titanate (PZT) stacks present substantial technical challenges to electronic systems. The work in this study shows that an alternative approach can be pursued by using subunits extracted from prototype stacks. Piezoelectric and dielectric integrity was maintained even though the PZT plate specimens experienced an additional loading process involved with the extraction after factory poling. Extracted 10-layer plate specimens were studied by an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 108 cycles, both at room temperature (22°C) and at 50°C. The elevated temperature had a defined impact on the fatigue of PZT stacks. About 48 and 28% reductions were observed in the piezoelectric and dielectric coefficients, respectively, after 108 cycles at 50°C, compared with reductions of 25 and 15% in the respective coefficients at 22°C. At the same time, the loss tangent varied to a limited extent. The evolution of PZT-electrode interfacial layers or nearby dielectric layers should account for the difference in the fatigue rates of piezoelectric and dielectric coefficients. But the basic contribution to observed fatigue may result from the buildup of a bias field that finally suppressed the motion of the domain walls. Finally, monitoring of dielectric coefficients can be an effective tool for on-line lifetime prediction of PZT stacks in service if a failure criterion is defined properly.

  3. Determination of the duty cycle of WLAN for realistic radio frequency electromagnetic field exposure assessment.

    Science.gov (United States)

    Joseph, Wout; Pareit, Daan; Vermeeren, Günter; Naudts, Dries; Verloock, Leen; Martens, Luc; Moerman, Ingrid

    2013-01-01

    Wireless Local Area Networks (WLANs) are commonly deployed in various environments. The WLAN data packets are not transmitted continuously but often worst-case exposure of WLAN is assessed, assuming 100% activity and leading to huge overestimations. Actual duty cycles of WLAN are thus of importance for time-averaging of exposure when checking compliance with international guidelines on limiting adverse health effects. In this paper, duty cycles of WLAN using Wi-Fi technology are determined for exposure assessment on large scale at 179 locations for different environments and activities (file transfer, video streaming, audio, surfing on the internet, etc.). The median duty cycle equals 1.4% and the 95th percentile is 10.4% (standard deviation SD = 6.4%). Largest duty cycles are observed in urban and industrial environments. For actual applications, the theoretical upper limit for the WLAN duty cycle is 69.8% and 94.7% for maximum and minimum physical data rate, respectively. For lower data rates, higher duty cycles will occur. Although counterintuitive at first sight, poor WLAN connections result in higher possible exposures. File transfer at maximum data rate results in median duty cycles of 47.6% (SD = 16%), while it results in median values of 91.5% (SD = 18%) at minimum data rate. Surfing and audio streaming are less intensively using the wireless medium and therefore have median duty cycles lower than 3.2% (SD = 0.5-7.5%). For a specific example, overestimations up to a factor 8 for electric fields occur, when considering 100% activity compared to realistic duty cycles. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. 40 CFR 1045.505 - How do I test engines using discrete-mode or ramped-modal duty cycles?

    Science.gov (United States)

    2010-07-01

    ...-mode or ramped-modal duty cycles? 1045.505 Section 1045.505 Protection of Environment ENVIRONMENTAL...-modal duty cycles? (a) This section describes how to test engines under steady-state conditions. We... Act. Conduct duty-cycle testing as follows: (1) For discrete-mode testing, sample emissions separately...

  5. 40 CFR 1042.505 - Testing engines using discrete-mode or ramped-modal duty cycles.

    Science.gov (United States)

    2010-07-01

    ... ramped-modal duty cycles. 1042.505 Section 1042.505 Protection of Environment ENVIRONMENTAL PROTECTION... duty cycles. This section describes how to test engines under steady-state conditions. In some cases, we allow you to choose the appropriate steady-state duty cycle for an engine. In these cases, you...

  6. A Biologically Inspired Energy-Efficient Duty Cycle Design Method for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2017-01-01

    Full Text Available The recent success of emerging wireless sensor networks technology has encouraged researchers to develop new energy-efficient duty cycle design algorithm in this field. The energy-efficient duty cycle design problem is a typical NP-hard combinatorial optimization problem. In this paper, we investigate an improved elite immune evolutionary algorithm (IEIEA strategy to optimize energy-efficient duty cycle design scheme and monitored area jointly to enhance the network lifetimes. Simulation results show that the network lifetime of the proposed IEIEA method increased compared to the other two methods, which means that the proposed method improves the full coverage constraints.

  7. Internet Enabled Remote Driving of a Combat Hybrid Electric Power System for Duty Cycle Measurement

    National Research Council Canada - National Science Library

    Goodell, Jarrett; Compere, Marc; Smith, Wilford; Holtz, Dale; Brudnak, Mark; Pozolo, Mike; Paul, Victor; Mohammad, Syed; Mortsfield, Todd; Shvartsman, Andrey

    2007-01-01

    This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware, both of which were used to measure the duty cycle of a combat vehicle in a virtual...

  8. Imprints of quasar duty cycle on the 21cm signal from the Epoch of Reionization

    Science.gov (United States)

    Bolgar, Florian; Eames, Evan; Hottier, Clément; Semelin, Benoit

    2018-05-01

    Quasars contribute to the 21-cm signal from the Epoch of Reionization (EoR) primarily through their ionizing UV and X-ray emission. However, their radio continuum and Lyman-band emission also regulates the 21-cm signal in their direct environment, potentially leaving the imprint of their duty cycle. We develop a model for the radio and UV luminosity functions of quasars from the EoR, and constrain it using recent observations. Our model is consistent with the recent discovery of the quasar J1342+0928 at redshift ˜7.5, and also predicts only a few quasars suitable for 21-cm forest observations (˜10 mJy) in the sky. We exhibit a new effect on the 21-cm signal observed against the CMB: a radio-loud quasar can leave the imprint of its duty cycle on the 21-cm tomography. We apply this effect in a cosmological simulation and conclude that the effect of typical radio-loud quasars is most likely negligible in an SKA field of view. For a ˜10mJy quasar the effect is stronger though hardly observable at SKA resolution. Then we study the contribution of the lyman band (Ly-α to Ly-β) emission of quasars to the Wouthuisen-Field coupling. The collective effect of quasars on the 21-cm power spectrum is larger than the thermal noise at low k, though featureless. However, a distinctive pattern around the brightest quasars in an SKA field of view may be observable in the tomography, encoding the duration of their duty cycle. This pattern has a high signal-to-noise ratio for the brightest quasar in a typical SKA shallow survey.

  9. ZENK expression in the auditory pathway of black-capped chickadees (Poecile atricapillus) as a function of D note number and duty cycle of chick-a-dee calls.

    Science.gov (United States)

    Scully, Erin N; Schuldhaus, Brenna C; Congdon, Jenna V; Hahn, Allison H; Campbell, Kimberley A; Wilson, David R; Sturdy, Christopher B

    2018-06-08

    Black-capped chickadees (Poecile atricapillus) use their namesake chick-a-dee call for multiple functions, altering the features of the call depending on context. For example, duty cycle (the proportion of time filled by vocalizations) and fine structure traits (e.g., number of D notes) can encode contextual factors, such as predator size and food quality. Wilson and Mennill [1] found that chickadees show stronger behavioral responses to playback of chick-a-dee calls with higher duty cycles, but not to the number of D notes. That is, independent of the number of D notes in a call, but dependent on the overall proportion of time filled with vocalization, birds responded more to higher duty cycle playback compared to lower duty cycle playback. Here we presented chickadees with chick-a-dee calls that contained either two D (referred to hereafter as 2 D) notes with a low duty cycle, 2 D notes with a high duty cycle, 10 D notes with a high duty cycle, or 2 D notes with a high duty cycle but played in reverse (a non-signaling control). We then measured ZENK expression in the auditory nuclei where perceptual discrimination is thought to occur. Based on the behavioral results of Wilson and Mennill [1], we predicted we would observe the highest ZENK expression in response to forward-playing calls with high duty cycles; we predicted we would observe no significant difference in ZENK expression between forward-playing high duty cycle playbacks (2 D or 10 D). We found no significant difference between forward-playing 2 D and 10 D high duty cycle playbacks. However, contrary to our predictions, we did not find any effects of altering the duty cycle or note number presented. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Research on Correlation between Vehicle Cycle and Engine Cycle in Heavy-duty commercial vehicle

    Science.gov (United States)

    lin, Chen; Zhong, Wang; Shuai, Liu

    2017-12-01

    In order to study the correlation between vehicle cycle and engine cycle in heavy commercial vehicles, the conversion model of vehicle cycle to engine cycle is constructed based on the vehicle power system theory and shift strategy, which considers the verification on diesel truck. The results show that the model has high rationality and reliability in engine operation. In the acceleration process of high speed, the difference of model gear selection leads to the actual deviation. Compared with the drum test, the engine speed distribution obtained by the model deviates to right, which fits to the lower grade. The grade selection has high influence on the model.

  11. Effects of duty cycle on microstructure and corrosion behavior of TiC coatings prepared by DC pulsed plasma CVD

    International Nuclear Information System (INIS)

    Shanaghi, Ali; Rouhaghdam, Ali Reza Sabour; Ahangarani, Shahrokh; Chu, Paul K.; Farahani, Taghi Shahrabi

    2012-01-01

    Titanium carbide coatings are deposited on hot-work steel (H 11 ) by plasma-assisted chemical vapor deposition (PACVD) and the dependence of the corrosion behavior on fabrication parameters is investigated. Grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), Raman and electrochemical tests are used to study the structure as well as corrosion behaviors. Grazing incidence X-ray diffraction reveals the (2 0 0) plane implying that the TiC coatings are deposited via the kinetics-limited crystal growth mechanism and under thermodynamically stable conditions. The SEM results indicate that the formation of a homogeneous and uniform titanium carbide nanostructure coatings. Potentiodynamic and electrochemical impedance tests performed in 0.5 M H 2 SO 4 and 0.05 M NaCl show that the TiC coating produced using a 40% duty cycle possesses high corrosion resistance in both media. The R p values of the TiC coating (50% duty cycle) in 0.05 M NaCl and the other TiC coating (40% duty cycle) in 0.5 M H 2 SO 4 are approximately four and sixteen orders of magnitude higher than that of the bare steel, respectively. Our results reveal that the duty cycles not only affect the structure and morphology of the coatings but also influence the electrochemical properties.

  12. Reliability-Aware Cooperative Node Sleeping and Clustering in Duty-Cycled Sensors Networks

    Directory of Open Access Journals (Sweden)

    Jeungeun Song

    2018-01-01

    Full Text Available Duty-cycled sensor networks provide a new perspective for improvement of energy efficiency and reliability assurance of multi-hop cooperative sensor networks. In this paper, we consider the energy-efficient cooperative node sleeping and clustering problems in cooperative sensor networks where clusters of relay nodes jointly transmit sensory data to the next hop. Our key idea for guaranteeing reliability is to exploit the on-demand number of cooperative nodes, facilitating the prediction of personalized end-to-end (ETE reliability. Namely, a novel reliability-aware cooperative routing (RCR scheme is proposed to select k-cooperative nodes at every hop (RCR-selection. After selecting k cooperative nodes at every hop, all of the non-cooperative nodes will go into sleep status. In order to solve the cooperative node clustering problem, we propose the RCR-based optimal relay assignment and cooperative data delivery (RCR-delivery scheme to provide a low-communication-overhead data transmission and an optimal duty cycle for a given number of cooperative nodes when the network is dynamic, which enables part of cooperative nodes to switch into idle status for further energy saving. Through the extensive OPNET-based simulations, we show that the proposed scheme significantly outperforms the existing geographic routing schemes and beaconless geographic routings in wireless sensor networks with a highly dynamic wireless channel and controls energy consumption, while ETE reliability is effectively guaranteed.

  13. Batu Pahat Driving Cycle for Light Duty Gasoline Engine

    Science.gov (United States)

    Zainul Abidin, Zainul Ameerul Ikhsan B.; Faisal Hushim, Mohd; Ahmad, Osman Bin

    2017-08-01

    Driving cycle is a series of data points that represents the vehicle speed versus time. Transient driving cycles involve many changes such as frequent speed changes during typical on-road driving condition [2]. Model driving cycles involve protracted periods at constant speeds. The Batu Pahat Driving Cycle (BPDC) developed to represent the driving pattern of people in a district of Batu Pahat. Based on this driving cycle, it will be a reference to other researchers to study about the gases emission release and fuel consumption by the vehicle on the dynamometer or automotive simulation based on this driving cycle. Existing driving cycles used such as the New European Driving Cycle (NEDC), the Federal Test Procedure (FTP-72/75, and Japan 10-15 Mode Cycle is not appropriate for Batu Pahat district because of different road conditions, driving habits and environmental of developed driving cycle countries are not same [2][14]. Batu Pahat drive cycle was developed for low-capacity gasoline engine under 150 cc and operating on urban roads, rural roads and road around Universiti Tun Hussein Onn. The importance of these driving cycle as the reference for other research to measure and do automotive simulation regarding fuel consumption and gas emission release from the motorcycle for these three type of driving cycle area. Another use for driving cycles is in vehicle simulations [3]. More specifically, they are used in propulsion system simulations to predict the performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components [18]. Data collection methods used in this study is the use of Global Positioning System (GPS). The results obtained are not similar to each other due to differences in congestion on data taken. From the driving cycle graph obtained, such as the average velocity, maximum velocity, the duration and Positive Acceleration Kinetic Energy (PKE) can be determined. In addition, the best

  14. Accessing data transfer reliability for duty cycled mobile wireless sensor network

    International Nuclear Information System (INIS)

    Shaikh, F.K.

    2014-01-01

    Mobility in WSNs (Wireless Sensor Networks) introduces significant challenges which do not arise in static WSNs. Reliable data transport is an important aspect of attaining consistency and QoS (Quality of Service) in several applications of MWSNs (Mobile Wireless Sensor Networks). It is important to understand how each of the wireless sensor networking characteristics such as duty cycling, collisions, contention and mobility affects the reliability of data transfer. If reliability is not managed well, the MWSN can suffer from overheads which reduce its applicability in the real world. In this paper, reliability assessment is being studied by deploying MWSN in different indoor and outdoor scenarios with various duty cycles of the motes and speeds of the mobile mote. Results show that the reliability is greatly affected by the duty cycled motes and the mobility using inherent broadcast mechanisms. (author)

  15. Effect of duty-cycles on the air plasma gas-phase of dielectric barrier discharges

    Science.gov (United States)

    Barni, R.; Biganzoli, I.; Dell'Orto, E. C.; Riccardi, C.

    2015-10-01

    An experimental investigation concerning the effects of a duty-cycle in the supply of a dielectric barrier discharge in atmospheric pressure air has been performed. Electrical characteristics of the discharge have been measured, focusing mainly on the statistical properties of the current filaments and on dielectric surface charging, both affected by the frequent repetition of breakdown imposed by the duty-cycle. Information on the gas-phase composition was gathered too. In particular, a strong enhancement in the ozone formation rate is observed when suitable long pauses separate the active discharge phases. A simulation of the chemical kinetics in the gas-phase, based on a simplified discharge modeling, is briefly described in order to shed light on the observed increase in ozone production. The effect of a duty-cycle on surface modification of polymeric films in order to increase their wettability has been investigated too.

  16. Analytical Model for LLC Resonant Converter With Variable Duty-Cycle Control

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    are identified and discussed. The proposed model enables a better understanding of the operation characteristics and fast parameter design of the LLC converter, which otherwise cannot be achieved by the existing simulation based methods and numerical models. The results obtained from the proposed model......In LLC resonant converters, the variable duty-cycle control is usually combined with a variable frequency control to widen the gain range, improve the light-load efficiency, or suppress the inrush current during start-up. However, a proper analytical model for the variable duty-cycle controlled LLC...... converter is still not available due to the complexity of operation modes and the nonlinearity of steady-state equations. This paper makes the efforts to develop an analytical model for the LLC converter with variable duty-cycle control. All possible operation models and critical operation characteristics...

  17. CMOS single-stage input-powered bridge rectifier with boost switch and duty cycle control

    Science.gov (United States)

    Radzuan, Roskhatijah; Mohd Salleh, Mohd Khairul; Hamzah, Mustafar Kamal; Ab Wahab, Norfishah

    2017-06-01

    This paper presents a single-stage input-powered bridge rectifier with boost switch for wireless-powered devices such as biomedical implants and wireless sensor nodes. Realised using CMOS process technology, it employs a duty cycle switch control to achieve high output voltage using boost technique, leading to a high output power conversion. It has only six external connections with the boost inductance. The input frequency of the bridge rectifier is set at 50 Hz, while the switching frequency is 100 kHz. The proposed circuit is fabricated on a single 0.18-micron CMOS die with a space area of 0.024 mm2. The simulated and measured results show good agreement.

  18. Research on Fuel Consumption of Hybrid Bulldozer under Typical Duty Cycle

    Science.gov (United States)

    Song, Qiang; Wang, Wen-Jun; Jia, Chao; Yao, You-Liang; Wang, Sheng-Bo

    The hybrid drive bulldozer adopts a dual-motor independent drive system with engine-generator assembly as its power source. The mathematical model of the whole system is constructed on the software platform of MATLAB/Simulink. And then according to the velocity data gained from a real test experiment, a typical duty cycle is build up. Finally the fuel consumption of the bulldozer is calculated under this duty-cycle. Simulation results show that, compared with the traditional mechanical one, the hybrid electric drive system can save fuel up to 16% and therefore indicates great potential for lifting up fuel economy.

  19. Improving broadcast performance of radio duty-cycled Internet-of-Things devices

    NARCIS (Netherlands)

    Guclu, S.S.; Özcelebi, T.; Lukkien, J.J.

    2017-01-01

    Asynchronous Radio Duty Cycling (ARDC) protocols can make embedded networked devices more energy efficient by keeping their radio off most of the time without a need for synchronization between devices. Some ARDC protocols can operate under 6LoWPAN adaptation layer in order to enable the vision of

  20. Predictive Duty Cycle Control of Three-Phase Active-Front-End Rectifiers

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Chen, Wei

    2016-01-01

    This paper proposed an on-line optimizing duty cycle control approach for three-phase active-front-end rectifiers, aiming to obtain the optimal control actions under different operating conditions. Similar to finite control set model predictive control strategy, a cost function previously...

  1. Analysis of Fixed Duty Cycle Hysteretic Flyback Converter for Firing Set Applications.

    Energy Technology Data Exchange (ETDEWEB)

    Love, Thomas Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    This paper analyzes several performance aspects of the fixed-duty-cycle, hysteretic flyback converter topology typically used in firing sets. Topologies with and without active pulse-by-pulse current limiting are considered, and closed-form expressions in terms of basic operating parameters are derived.

  2. Resistance Torque Based Variable Duty-Cycle Control Method for a Stage II Compressor

    Science.gov (United States)

    Zhong, Meipeng; Zheng, Shuiying

    2017-07-01

    The resistance torque of a piston stage II compressor generates strenuous fluctuations in a rotational period, and this can lead to negative influences on the working performance of the compressor. To restrain the strenuous fluctuations in the piston stage II compressor, a variable duty-cycle control method based on the resistance torque is proposed. A dynamic model of a stage II compressor is set up, and the resistance torque and other characteristic parameters are acquired as the control targets. Then, a variable duty-cycle control method is applied to track the resistance torque, thereby improving the working performance of the compressor. Simulated results show that the compressor, driven by the proposed method, requires lower current, while the rotating speed and the output torque remain comparable to the traditional variable-frequency control methods. A variable duty-cycle control system is developed, and the experimental results prove that the proposed method can help reduce the specific power, input power, and working noise of the compressor to 0.97 kW·m-3·min-1, 0.09 kW and 3.10 dB, respectively, under the same conditions of discharge pressure of 2.00 MPa and a discharge volume of 0.095 m3/min. The proposed variable duty-cycle control method tracks the resistance torque dynamically, and improves the working performance of a Stage II Compressor. The proposed variable duty-cycle control method can be applied to other compressors, and can provide theoretical guidance for the compressor.

  3. An Effective Delay Reduction Approach through a Portion of Nodes with a Larger Duty Cycle for Industrial WSNs.

    Science.gov (United States)

    Wu, Minrui; Wu, Yanhui; Liu, Chuyao; Cai, Zhiping; Xiong, Neal N; Liu, Anfeng; Ma, Ming

    2018-05-12

    For Industrial Wireless Sensor Networks (IWSNs), sending data with timely style to the stink (or control center, CC) that is monitored by sensor nodes is a challenging issue. However, in order to save energy, wireless sensor networks based on a duty cycle are widely used in the industrial field, which can bring great delay to data transmission. We observe that if the duty cycle of a small number of nodes in the network is set to 1, the sleep delay caused by the duty cycle can be effectively reduced. Thus, in this paper, a novel Portion of Nodes with Larger Duty Cycle (PNLDC) scheme is proposed to reduce delay and optimize energy efficiency for IWSNs. In the PNLDC scheme, a portion of nodes are selected to set their duty cycle to 1, and the proportion of nodes with the duty cycle of 1 is determined according to the energy abundance of the area in which the node is located. The more the residual energy in the region, the greater the proportion of the selected nodes. Because there are a certain proportion of nodes with the duty cycle of 1 in the network, the PNLDC scheme can effectively reduce delay in IWSNs. The performance analysis and experimental results show that the proposed scheme significantly reduces the delay for forwarding data by 8.9~26.4% and delay for detection by 2.1~24.6% without reducing the network lifetime when compared with the fixed duty cycle method. Meanwhile, compared with the dynamic duty cycle strategy, the proposed scheme has certain advantages in terms of energy utilization and delay reduction.

  4. 40 CFR 86.098-10 - Emission standards for 1998 and later model year Otto-cycle heavy-duty engines and vehicles.

    Science.gov (United States)

    2010-07-01

    ... model year Otto-cycle heavy-duty engines and vehicles. 86.098-10 Section 86.098-10 Protection of..., exhaust emissions from new 1998 and later model year Otto-cycle heavy-duty engines shall not exceed: (i) For Otto-cycle heavy-duty engines fueled with either gasoline or liquefied petroleum gas, and intended...

  5. 40 CFR 1048.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

    Science.gov (United States)

    2010-07-01

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

  6. 40 CFR 1039.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

    Science.gov (United States)

    2010-07-01

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

  7. Optimization of carrier frequency and duty cycle for pulse modulation of biological signals.

    Science.gov (United States)

    Tandon, S N; Singh, S; Sharma, P K; Khosla, S

    1980-10-01

    Digital modulation techniques are commonly used for the recording and transmission of biological signals. Hitherto, the choice of subcarrier frequency for recording or transmission of biological signals has been arbitary and this usually results in poor signal to noise ratio (SNR) due to the limited frequency characteristics of the system. In the present study the frequency characteristics of the system (first order approximation) has been taken to be that of a Butterworth filter. Computations based on this assumption show that for a given input signal there exists an optimum subcarrier frequency and a corresponding optimum duty cycle which would give maximum SNR of the system. For convenience, a nomogram has been prepared and it has been shown that for a given frequency response of the system, the nomogram could be used for selecting an optimum subcarrier frequency and a corresponding duty cycle. The theoretical formulations have been verified with experimental work.

  8. A Pseudo Fractional-N Clock Generator with 50% Duty Cycle Output

    Science.gov (United States)

    Yang, Wei-Bin; Lo, Yu-Lung; Chao, Ting-Sheng

    A proposed pseudo fractional-N clock generator with 50% duty cycle output is presented by using the pseudo fractional-N controller for SoC chips and the dynamic frequency scaling applications. The different clock frequencies can be generated with the particular phase combinations of a four-stage voltage-controlled oscillator (VCO). It has been fabricated in a 0.13µm CMOS technology, and work with a supply voltage of 1.2V. According to measured results, the frequency range of the proposed pseudo fractional-N clock generator is from 71.4MHz to 1GHz and the peak-to-peak jitter is less than 5% of the output period. Duty cycle error rates of the output clock frequencies are from 0.8% to 2% and the measured power dissipation of the pseudo fractional-N controller is 146µW at 304MHz.

  9. A Novel Analog-to-digital conversion Technique using nonlinear duty-cycle modulation

    OpenAIRE

    Jean Mbihi; François Ndjali Beng; Martin Kom; Léandre Nneme Nneme

    2012-01-01

    A new type of analog-to-digital conversion technique is presented in this paper. The interfacing hardware is a very simple nonlinear circuit with 1-bit modulated output. As a implication, behind the hardware simplicity retained is hidden a dreadful nonlinear duty-cycle modulation ratio. However, the overall nonlinear behavior embeds a sufficiently wide linear range, for a rigorous digital reconstitution of the analog input signal using a standard linear filter. Simulation and experimental r...

  10. Energy Harvesting Wireless Sensor Networks: From Characterization to Duty Cycle Dimensioning

    OpenAIRE

    Oueis , Jad; Stanica , Razvan; Valois , Fabrice

    2016-01-01

    International audience; Energy harvesting capabilities are challenging our understanding of wireless sensor networks by adding recharging capacity to sensor nodes. This has a significant impact on the communication paradigm, as networking mechanisms can benefit from these potentially infinite renewable energy sources. In this work, we study the consequences of implementing photovoltaic energy harvesting on the duty cycle of a wireless sensor node, in both outdoor and indoor scenarios. We show...

  11. Duty cycle testing and performance evaluation of the SM-229 teleoperator

    International Nuclear Information System (INIS)

    Stoughton, R.S.; Kuban, D.P.

    1985-11-01

    This paper contains the first known experimental studies and analyses of teleoperator performance for specific duty cycles. The results are presented in two distinct areas as position usage patterns, and as three-dimensional power grids. The position usage patterns are a valuable means to assess the available motion range. The power grids are a unique concept for evaluating joint performance. Final conclusions contain recommendations to upgrade the teleoperator for optimum performance. 3 refs., 16 figs

  12. Availability and End-to-end Reliability in Low Duty Cycle Multihop Wireless Sensor Networks.

    Science.gov (United States)

    Suhonen, Jukka; Hämäläinen, Timo D; Hännikäinen, Marko

    2009-01-01

    A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER.

  13. Availability and End-to-end Reliability in Low Duty Cycle MultihopWireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Timo D. Hämäläinen

    2009-03-01

    Full Text Available A wireless sensor network (WSN is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS. Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER. The forwarding algorithm guarantees reliability up to 30% PER.

  14. A Cross-Layer Duty Cycle MAC Protocol Supporting a Pipeline Feature for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Young-Chon Kim

    2011-05-01

    Full Text Available Although the conventional duty cycle MAC protocols for Wireless Sensor Networks (WSNs such as RMAC perform well in terms of saving energy and reducing end-to-end delivery latency, they were designed independently and require an extra routing protocol in the network layer to provide path information for the MAC layer. In this paper, we propose a new cross-layer duty cycle MAC protocol with data forwarding supporting a pipeline feature (P-MAC for WSNs. P-MAC first divides the whole network into many grades around the sink. Each node identifies its grade according to its logical hop distance to the sink and simultaneously establishes a sleep/wakeup schedule using the grade information. Those nodes in the same grade keep the same schedule, which is staggered with the schedule of the nodes in the adjacent grade. Then a variation of the RTS/CTS handshake mechanism is used to forward data continuously in a pipeline fashion from the higher grade to the lower grade nodes and finally to the sink. No extra routing overhead is needed, thus increasing the network scalability while maintaining the superiority of duty-cycling. The simulation results in OPNET show that P-MAC has better performance than S-MAC and RMAC in terms of packet delivery latency and energy efficiency.

  15. Soft switching resonant converter with duty-cycle control in DC micro-grid system

    Science.gov (United States)

    Lin, Bor-Ren

    2018-01-01

    Resonant converter has been widely used for the benefits of low switching losses and high circuit efficiency. However, the wide frequency variation is the main drawback of resonant converter. This paper studies a new modular resonant converter with duty-cycle control to overcome this problem and realise the advantages of low switching losses, no reverse recovery current loss, balance input split voltages and constant frequency operation for medium voltage direct currentgrid or system network. Series full-bridge (FB) converters are used in the studied circuit in order to reduce the voltage stresses and power rating on power semiconductors. Flying capacitor is used between two FB converters to balance input split voltages. Two circuit modules are paralleled on the secondary side to lessen the current rating of rectifier diodes and the size of magnetic components. The resonant tank is operated at inductive load circuit to help power switches to be turned on at zero voltage with wide load range. The pulse-width modulation scheme is used to regulate output voltage. Experimental verifications are provided to show the performance of the proposed circuit.

  16. 40 CFR 86.005-10 - Emission standards for 2005 and later model year Otto-cycle heavy-duty engines and vehicles.

    Science.gov (United States)

    2010-07-01

    ... model year Otto-cycle heavy-duty engines and vehicles. 86.005-10 Section 86.005-10 Protection of... AND IN-USE HIGHWAY VEHICLES AND ENGINES General Provisions for Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Engines, and for 1985 and Later...

  17. Prolonged electrical stimulation-induced gluteal and hamstring muscle activation and sitting pressure in spinal cord injury: Effect of duty cycle

    NARCIS (Netherlands)

    MSc Karin J.A. Legemate; MD Christof A. J. Smit; MSc Anja de Koning; PhD Sonja de Groot; MD, PhD Janneke M. Stolwijk-Swuste; PhD Thomas W.H. Janssen

    2013-01-01

    Abstract—Pressure ulcers (PUs) are highly prevalent in people with spinal cord injury (SCI). Electrical stimulation (ES) activates muscles and might reduce risk factors. Our objectives were to study and compare the effects of two duty cycles during 3 h of ES-induced gluteal and hamstring activation

  18. Prolonged electrical stimulation-induced gluteal and hamstring muscle activation and sitting pressure in spinal cord injury : Effect of duty cycle

    NARCIS (Netherlands)

    Smit, Christof A. J.; Legemate, Karin J. A.; de Koning, Anja; de Groot, Sonja; Stolwijk-Swuste, Janneke M.; Janssen, Thomas W. J.

    2013-01-01

    Pressure ulcers (PUs) are highly prevalent in people with spinal cord injury (SCI). Electrical stimulation (ES) activates muscles and might reduce risk factors. Our objectives were to study and compare the effects of two duty cycles during 3 h of ES-induced gluteal and hamstring activation on

  19. A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation

    Directory of Open Access Journals (Sweden)

    Taesik Kim

    2017-02-01

    Full Text Available Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.

  20. Model based control for waste heat recovery rankine cycle system in heavy duty trucks

    OpenAIRE

    Grelet, Vincent; Dufour, Pascal; Nadri, Madiha; Lemort, Vincent; Reiche, Thomas

    2015-01-01

    Driven by future emissions legislations and increase in fuel prices engine, gas heat recovering has recently attracted a lot of interest. In the past few years, a high number of studies have shown the interest of energy recovery Rankine based systems for heavy duty trucks engine compounding. Recent studies have brought a significant potential for such a system in a Heavy Duty (HD) vehicle, which can lead to a decrease in fuel consumption of about 5% [Wang et al. (2011)] and reduce engine emis...

  1. Energy storage technologies and hybrid architectures for specific diesel-driven rail duty cycles: Design and system integration aspects

    International Nuclear Information System (INIS)

    Meinert, M.; Prenleloup, P.; Schmid, S.; Palacin, R.

    2015-01-01

    Highlights: • We assessed integration of energy storage systems into hybrid system architectures. • We considered mechanical and electrical energy storage systems. • Potential of different combinations has been analyzed by standardized duty cycles. • Most promising are diesel-driven suburban, regional and shunting operations. • Double-layer capacitors and Lithium-ion batteries have the highest potential. - Abstract: The use of diesel-driven traction is an intrinsic part of the functioning of railway systems and it is expected to continue being so for the foreseeable future. The recent introduction of more restrictive greenhouse gas emission levels and other legislation aiming at the improvement of the environmental performance of railway systems has led to the need of exploring alternatives for cleaner diesel rolling stock. This paper focuses on assessing energy storage systems and the design of hybrid system architectures to determine their potential use in specific diesel-driven rail duty cycles. Hydrostatic accumulators, flywheels, Lithium-ion batteries and double-layer capacitors have been assessed and used to design hybrid system architectures. The potential of the different technology combinations has been analyzed using standardized duty cycles enhanced with gradient profiles related to suburban, regional and shunting operations. The results show that double-layer capacitors and Lithium-ion batteries have the highest potential to be successfully integrated into the system architecture of diesel-driven rail vehicles. Furthermore, the results also suggest that combining these two energy storage technologies into a single hybridisation package is a highly promising design that draws on their strengthens without any significant drawbacks.

  2. The outburst duration and duty cycle of GRS1915+105

    Science.gov (United States)

    Deegan, Patrick; Combet, Céline; Wynn, Graham A.

    2009-12-01

    The extraordinarily long outburst of GRS1915+105 makes it one of the most remarkable low-mass X-ray binaries (LMXBs). It has been in a state of constant outburst since its discovery in 1992, an eruption which has persisted ~100 times longer than those of more typical LXMBs. The long orbital period of GRS1915+105 implies that it contains large and massive accretion disc which is able to fuel its extreme outburst. In this paper, we address the longevity of the outburst and quiescence phases of GRS1915+105 using smooth particle hydrodynamics (SPH) simulations of its accretion disc through many outburst cycles. Our model is set in the two-α framework and includes the effects of the thermoviscous instability, tidal torques, irradiation by central X-rays and wind mass loss. We explore the model parameter space and examine the impact of the various ingredients. We predict that the outburst of GRS1915+105 should last a minimum of 20yr and possibly up to ~100yr if X-ray irradiation is very significant. The predicted recurrence times are of the order of 104yr, making the X-ray duty cycle a few 0.1 per cent. Such a low duty cycle may mean that GRS1915+105 is not an anomaly among the more standard LMXBs and that many similar, but quiescent, systems could be present in the Galaxy.

  3. Battery Dimensioning and Life Cycle Costs Analysis for a Heavy-Duty Truck Considering the Requirements of Long-Haul Transportation

    OpenAIRE

    Mareev, Ivan; Becker, Jan Nicolas; Sauer, Dirk Uwe

    2018-01-01

    The use of heavy-duty battery electric trucks for long-haul transportation is challenging because of the required high energy amounts and thus the high capacity of traction batteries. Furthermore a high capacity battery implies high initial costs for the electric vehicle. This study investigates the required battery capacity for battery electric trucks considering the requirements of long-haul transportation in Germany and compares the life cycle costs of battery electric trucks and conventio...

  4. Influence of Duty Cycle on Ozone Generation and Discharge Using Volume Dielectric Barrier Discharge

    Czech Academy of Sciences Publication Activity Database

    Wei, L.S.; Pongrác, Branislav; Zhang, Y.F.; Liang, X.; Prukner, Václav; Šimek, Milan

    2018-01-01

    Roč. 38, č. 2 (2018), s. 355-364 ISSN 0272-4324 R&D Projects: GA ČR(CZ) GA15-04023S Institutional support: RVO:61389021 Keywords : Ozone generation * Volume dielectric barrier discharge * Electrical characteristics * Duty cycle * Adjustable ozone concentration Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 https://link.springer.com/article/10.1007%2Fs11090-017-9866-y

  5. Determination of Duty Cycle for Energy Storage Systems in a Renewables (Solar) Firming Application

    Energy Technology Data Exchange (ETDEWEB)

    Schoenwald, David A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electric Power Systems Research Dept.; Ellison, James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electric Power Systems Research Dept.

    2016-04-01

    This report supplements the document, “Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage Systems,” issued in a revised version in April 2016, which will include the renewables (solar) firming application for an energy storage system (ESS). This report provides the background and documentation associated with the determination of a duty cycle for an ESS operated in a renewables (solar) firming application for the purpose of measuring and expressing ESS performance in accordance with the ESS performance protocol.

  6. Investigation of high duty factor ISR RFQ-1000

    International Nuclear Information System (INIS)

    Lu, Y.R.; Chen, C.E.; Fang, J.X.; Gao, S.L.; Guo, J. F.; Guo, Z.Y.; Li, D.S.; Li, W.G.; Pan, O.J.; Ren, X.T.; Wu, Y.; Yan, X.Q.; Yu, J.X.; Yu, M.L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

    2003-01-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O + and negative O - ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O - beam current reached 660 μA at a transmission efficiency of more than 82%. The N + beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper

  7. Investigation of high duty factor ISR RFQ-1000

    Science.gov (United States)

    Lu, Y. R.; Chen, C. E.; Fang, J. X.; Gao, S. L.; Guo, J. F.; Guo, Z. Y.; Li, D. S.; Li, W. G.; Pan, O. J.; Ren, X. T.; Wu, Y.; Yan, X. Q.; Yu, J. X.; Yu, M. L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

    2003-12-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O+ and negative O- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O- beam current reached 660 μA at a transmission efficiency of more than 82%. The N+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper.

  8. Investigation of high duty factor ISR RFQ-1000

    CERN Document Server

    Lu, Y R; Fang, J X; Gao, S L; Guo, J F; Guo, Z Y; Li, D S; Li, W G; Pan, O J; Ren, X T; Wu, Y; Yan, X Q; Yu Jin Xiang; Yu, M L; Ratzinger, U; Deitinghoff, H; Klein, H; Schempp, A

    2003-01-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O**+ and negative O**- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O**- beam current reached 660muA at a transmission efficiency of more than 82%. The N**+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1MeV ISR RFQ will be presented in this paper.

  9. Oxidation of tartrazine with ultraviolet light emitting diodes: pH and duty cycles effects.

    Science.gov (United States)

    Stewart, Brandon M; Miller, Michael E; Kempisty, David M; Stubbs, John; Harper, Willie F

    2018-03-01

    The presence of tartrazine (TAR) in the water cycle poses serious threats to human health. This study investigated the used of light emitting diodes (LEDs) in the advanced oxidation of TAR under different pH and duty cycle (DC) conditions. The first order reaction rate constant for TAR oxidation was positively correlated with DC, negatively correlated with pH, and typically greatest at pH 6. Chemical byproduct analysis indicated that OH addition, H abstraction, and electron transfer without molecule transfer were among the relevant reaction mechanisms for TAR degradation. Six byproducts were identified, four were reported for the first time, and two demonstrated that TAR rings were cleaved. This research is the first to determine the optimal pH for UVLED-driven oxidation of TAR and the first to identify new TAR-related byproducts from UVLED-based water treatment.

  10. Analysis of the response of a photovoltaic module subjected to pulsating light of variable duty cycle

    International Nuclear Information System (INIS)

    Zuñiga-Reyes, Marco A.; Sevilla-Camacho, P.Y.; Robles-Ocampo, J.B.; Lopez-Villarea, S. A.

    2017-01-01

    The present work analyzes the time domain response of polycrystalline and amorphous silicon modules subjected to a pulsed light signal, applied under conditions of darkness and controlled temperature. The applied light has a wavelength of 625 nm, a constant power of 5 Watts, a constant frequency of 10 kHz and a variable duty cycle. The response of the modules was analyzed in both direct current (DC) and alternating current (AC). The results of the research showed differences between the waveform and the amplitude of the output voltage of each of the manufacturing technologies of the modules. To validate the obtained results, the simulation of the response of a solar cell using its equivalent circuit in CA was performed. From the experimental and simulation tests it is observed that the relation between the duty cycle and the response of the modules of different technologies can be used for the monitoring and detection of faults or for the determination of the components of the AC equivalent circuit from the solar cells. (author)

  11. Effect of pulsed duty cycle control on tribological and corrosion properties of AISI-316 in cathodic cage plasma nitriding

    Science.gov (United States)

    Naeem, M.; Raza, H. A.; Shafiq, M.; Zaka-ul-Islam, M.; Iqbal, Javed; Díaz-Guillén, J. C.; Zakaullah, M.

    2017-11-01

    Austenitic stainless steels are of prime importance in many industrial sectors because of their excellent corrosion resistance; however, their poor mechanical and tribological features lead to their reduced applicability. In this regard, low-temperature cathodic cage plasma nitriding (CCPN) can be used to improve surface properties of steels without scarifying the inherent corrosion resistance. In this study, AISI-316 samples are processed in CCPN reactor at a temperature of 400 °C, for the treatment time of 4 h, at a pressure of 150 Pa and variable pulsed duty cycle (15-75%). The microstructure and mechanical features are analyzed using x-ray diffraction, scanning electron microscopy, microhardness tester and ball-on-disc wear tester. The anodic polarization test in 3.5% NaCl is conducted to examine the corrosion properties. The results show that hardness is enhanced up to 1327 HV at low duty cycle, which is considerably higher than base material (278 HV). The wear rate is found to be reduced up to 90% over base material by processing at low duty cycle. The base material exhibits severe abrasive wear, and the nitrided sample has dominant adhesive wear. The corrosion rate is found to be reduced up to 95% over base material for the sample nitrided at low duty cycle. This study shows that wear and corrosion resistance in CCPN can be significantly boosted by reducing the pulsed duty cycle.

  12. Heavy-duty approval test cycles: assessment of currently applied test cycles and theories for the development of new duty cycles

    NARCIS (Netherlands)

    Weijer, C.J.T. van de; Rijkeboer, R.C.

    1999-01-01

    In the development of the new emission reduction technologies, the benefits of the use of these technologies must be assessed for real-life engine use. As in practice engines are developed to perform as good as possible on the approval test cycle on the basis of which emission limits are set, it is

  13. 40 CFR 86.008-10 - Emission standards for 2008 and later model year Otto-cycle heavy-duty engines and vehicles.

    Science.gov (United States)

    2010-07-01

    ... model year Otto-cycle heavy-duty engines and vehicles. 86.008-10 Section 86.008-10 Protection of... Otto-cycle HDE. (d) Every manufacturer of new motor vehicle engines subject to the standards prescribed... production of heavy-duty Otto-cycle motor vehicle engines for model year 2008, except as explicitly allowed...

  14. Medium Truck Duty Cycle Data from Real-World Driving Environments: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lascurain, Mary Beth [ORNL; Franzese, Oscar [ORNL; Capps, Gary J [ORNL; Siekmann, Adam [ORNL; Thomas, Neil [ORNL; LaClair, Tim J [ORNL; Barker, Alan M [ORNL; Knee, Helmut E [ORNL

    2012-11-01

    Since the early part of the 20th century, the US trucking industry has provided a safe and economical means of moving commodities across the country. At present, nearly 80% of US domestic freight movement involves the use of trucks. The US Department of Energy (DOE) is spearheading a number of research efforts to improve heavy vehicle fuel efficiencies. This includes research in engine technologies (including hybrid and fuel cell technologies), lightweight materials, advanced fuels, and parasitic loss reductions. In addition, DOE is developing advanced tools and models to support heavy vehicle research and is leading the 21st Century Truck Partnership and the SuperTruck development effort. Both of these efforts have the common goal of decreasing the fuel consumption of heavy vehicles. In the case of SuperTruck, a goal of improving the overall freight efficiency of a combination tractor-trailer has been established. This Medium Truck Duty Cycle (MTDC) project is a critical element in DOE s vision for improved heavy vehicle energy efficiency; it is unique in that there is no other existing national database of characteristic duty cycles for medium trucks based on collecting data from Class 6 and 7 vehicles. It involves the collection of real-world data on medium trucks for various situational characteristics (e.g., rural/urban, freeway/arterial, congested/free-flowing, good/bad weather) and looks at the unique nature of medium trucks drive cycles (stop-and-go delivery, power takeoff, idle time, short-radius trips). This research provides a rich source of data that can contribute to the development of new tools for FE and modeling, provide DOE a sound basis upon which to make technology investment decisions, and provide a national archive of real-world-based medium-truck operational data to support energy efficiency research. The MTDC project involved a two-part field operational test (FOT). For the Part-1 FOT, three vehicles each from two vocations (urban transit and

  15. Kinematics and duty cycles of the SM-229 force-reflecting servomanipulator

    International Nuclear Information System (INIS)

    Stoughton, R.S.

    1986-02-01

    This report describes the first known experimental study of servomanipulator duty cycles to appear in the literature. The servomanipulator used was TeleOperator Systems Model SM-229. The experimental approach used was to record the joint positions and motor currents of the right slave arm at a rate of 10 Hz over about 50 h of typical remote manipulation operations. The results are presented as position usage patterns in joint and real-world coordinates, time-use histograms of joint velocities and motor currents, and three-dimensional mechanical power histograms for each joint. All results are presented in dimensionless form, scaled to the design ranges of the manipulator and the total operation time recorded. Applications of this study include improvements in kinematic ranges, gear reductions, motor sizings, drive configurations, and stress relief. Included in appendices are an uncertainty analysis, calibration procedures, and analysis of the kinematics of the manipulator. 12 refs., 42 figs., 15 tabs

  16. Duty-cycle and energetics of remnant radio-loud AGN

    Science.gov (United States)

    Turner, Ross J.

    2018-05-01

    Deriving the energetics of remnant and restarted active galactic nuclei (AGNs) is much more challenging than for active sources due to the complexity in accurately determining the time since the nucleus switched-off. I resolve this problem using a new approach that combines spectral ageing and dynamical models to tightly constrain the energetics and duty-cycles of dying sources. Fitting the shape of the integrated radio spectrum yields the fraction of the source age the nucleus is active; this, in addition to the flux density, source size, axis ratio, and properties of the host environment, provides a constraint on dynamical models describing the remnant radio source. This technique is used to derive the intrinsic properties of the well-studied remnant radio source B2 0924+30. This object is found to spend 50_{-12}^{+14} Myr in the active phase and a further 28_{-5}^{+6} Myr in the quiescent phase, have a jet kinetic power of 3.6_{-1.7}^{+3.0}× 10^{37} W, and a lobe magnetic field strength below equipartition at the 8σ level. The integrated spectra of restarted and intermittent radio sources are found to yield a `steep-shallow' shape when the previous outburst occurred within 100 Myr. The duty-cycle of B2 0924+30 is hence constrained to be δ < 0.15 by fitting the shortest time to the previous comparable outburst that does not appreciably modify the remnant spectrum. The time-averaged feedback energy imparted by AGNs into their host galaxy environments can in this manner be quantified.

  17. Investigation of duty cycle effect on corrosion properties of electrodeposited calcium phosphate coatings

    Energy Technology Data Exchange (ETDEWEB)

    Azem, Funda Ak, E-mail: funda.ak@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey); Delice, Tulay Koc, E-mail: tulaykocdelice@gmail.com [Dokuz Eylul University, The Graduate School of Natural and Applied Sciences, Buca, 35390 Izmir (Turkey); Ungan, Guler, E-mail: gulerungan@hotmail.com [Es Group, Izmir (Turkey); Cakir, Ahmet, E-mail: ahmet.cakir@deu.edu.tr [Dokuz Eylul University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Buca, 35390 Izmir (Turkey)

    2016-11-01

    The bioceramic calcium phosphate (CaP) is frequently used for improving bone fixation in titanium medical implants and thus increasing lifetime of the implant. It is known that the application of CaP coatings on metallic implant devices offers the possibility of combining the strength of the metals and the bioactivity of the ceramic materials. Many different techniques are available for producing CaP coatings. Electrochemical deposition method is widely used because of its ease of operation parameters, low temperature requirement, reproducibility and suitability for coating complex structures. This technique allows obtaining CaP coatings which promote bone in growth during the first healing period leading to permanent fixation. Electrochemical pulse technique is an alternative to calcium phosphate deposition techniques usually employed to cover orthopedic or dental titanium implant surfaces. Additionally, pulse electrodeposition technique can produce more uniform and denser CaP coatings on metallic implants. In this study, CaP based coatings were produced by electrochemical pulse technique on Ti6Al4V substrates. The resulting CaP deposits were investigated by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Corrosion properties of the CaP coatings were also investigated. The results showed that various duty cycle ranges have remarkably effect on morphology, crystallinity and corrosion properties of the produced CaP coatings. - Highlights: • Electrodeposited CaP based coating were produced by pulse deposition technique. • The pulsed electrodeposited coatings produced under 30% and 50% duty cycles were exhibited better corrosion resistance. • Produced coatings consist of irregular flake-like structure and compact network with fine needles.

  18. Prolonged electrical stimulation-induced gluteal and hamstring muscle activation and sitting pressure in spinal cord injury: Effect of duty cycle

    OpenAIRE

    Christof A. J. Smit, MD; Karin J. A. Legemate, MSc; Anja de Koning, MSc; Sonja de Groot, PhD; Janneke M. Stolwijk-Swuste, MD, PhD; Thomas W. J. Janssen, PhD

    2013-01-01

    Pressure ulcers (PUs) are highly prevalent in people with spinal cord injury (SCI). Electrical stimulation (ES) activates muscles and might reduce risk factors. Our objectives were to study and compare the effects of two duty cycles during 3 h of ES-induced gluteal and hamstring activation on interface pressure distribution in sitting individuals with SCI and study the usability of a newly developed electrode garment (ES shorts). Ten individuals with SCI participated in this study, in which t...

  19. Hybrid Simulation of Duty Cycle Influences on Pulse Modulated RF SiH4/Ar Discharge

    Science.gov (United States)

    Wang, Xifeng; Song, Yuanhong; Zhao, Shuxia; Dai, Zhongling; Wang, Younian

    2016-04-01

    A one-dimensional fluid/Monte-Carlo (MC) hybrid model is developed to describe capacitively coupled SiH4/Ar discharge, in which the lower electrode is applied by a RF source and pulse modulated by a square-wave, to investigate the modulation effects of the pulse duty cycle on the discharge mechanism. An electron Monte Carlo simulation is used to calculate the electron energy distribution as a function of position and time phase. Rate coefficients in chemical reactions can then be obtained and transferred to the fluid model for the calculation of electron temperature and densities of different species, such as electrons, ions, and radicals. The simulation results show that, the electron energy distribution f(ɛ) is modulated evidently within a pulse cycle, with its tail extending to higher energies during the power-on period, while shrinking back promptly in the afterglow period. Thus, the rate coefficients could be controlled during the discharge, resulting in modulation of the species composition on the substrate compared with continuous excitation. Meanwhile, more negative ions, like SiH-3 and SiH-2, may escape to the electrodes owing to the collapse of ambipolar electric fields, which is beneficial to films deposition. Pulse modulation is thus expected to provide additional methods to customize the plasma densities and components. supported by National Natural Science Foundation of China (No. 11275038)

  20. A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Detor, Andrew [General Electric Company, Niskayuna, NY (United States). GE Global Research; DiDomizio, Richard [General Electric Company, Niskayuna, NY (United States). GE Global Research; McAllister, Don [The Ohio State Univ., Columbus, OH (United States); Sampson, Erica [General Electric Company, Niskayuna, NY (United States). GE Global Research; Shi, Rongpei [The Ohio State Univ., Columbus, OH (United States); Zhou, Ning [General Electric Company, Niskayuna, NY (United States). GE Global Research

    2017-01-03

    The drive to increase combined cycle turbine efficiency from 62% to 65% for the next-generation advanced cycle requires a new heavy duty gas turbine wheel material capable of operating at 1200°F and above. Current wheel materials are limited by the stability of their major strengthening phase (gamma double prime), which coarsens at temperatures approaching 1200°F, resulting in a substantial reduction in strength. More advanced gamma prime superalloys, such as those used in jet engine turbine disks, are also not suitable due to size constraints; the gamma prime phase overages during the slow cooling rates inherent in processing thick-section turbine wheels. The current program addresses this need by screening two new alloy design concepts. The first concept exploits a gamma prime/gamma double prime coprecipitation reaction. Through manipulation of alloy chemistry, coprecipitation is controlled such that gamma double prime is used only to slow the growth of gamma prime during slow cooling, preventing over-aging, and allowing for subsequent heat treatment to maximize strength. In parallel, phase field modeling provides fundamental understanding of the coprecipitation reaction. The second concept uses oxide dispersion strengthening to improve on two existing alloys that exhibit excellent hold time fatigue crack growth resistance, but have insufficient strength to be considered for gas turbine wheels. Mechanical milling forces the dissolution of starting oxide powders into a metal matrix allowing for solid state precipitation of new, nanometer scale oxides that are effective at dispersion strengthening.

  1. High duty factor structures for e+e- storage rings

    International Nuclear Information System (INIS)

    Allen, M.A.; Karvonen, L.G.

    1976-01-01

    The next generation e + e - storage rings will need rf systems similar to those required for a continuous-duty linac of over 50 MeV. For the PEP Storage Ring at 18 GeV, it is presently planned to provide a peak accelerating voltage of 77 MV in 18 aluminum accelerating structures, each structure consisting of five slot-coupled cells operating in the π mode. Operating experience with the SPEAR five-cell structure is discussed. Power to each structure is provided by a 125-kW high-efficiency four-cavity klystron. No isolation has been used and the resulting interaction between the accelerating structures, klystrons and the stored beams is discussed

  2. RF system considerations for large high-duty-factor linacs

    International Nuclear Information System (INIS)

    Lynch, M.T.; Ziomek, C.D.; Tallerico, P.J.; Regan, A.H.; Eaton, L.; Lawrence, G.

    1994-01-01

    RF systems are often a major cost item for linacs, but this is especially true for large high-duty-factor linacs (up to and including CW) such as the Accelerator for Production of Tritium (APT) or the Accelerator for Transmutation of nuclear Waste (ATW). In addition, the high energy and high average beam current of these machines (approximately 1 GeV, 100--200 mA) leads to a need for excellent control of the accelerating fields in order to minimize the possibility of beam loss in the accelerator and the resulting activation. This paper will address the key considerations and limitations in the design of the RF system. These considerations impact the design of both the high power RF components and the RF controls. As might be expected, the two concerns sometimes lead to conflicting design requirements. For example minimum RF operating costs lead to a desire for operation near saturation of the high power RF generators in order to maximize the operating efficiency. Optimal control of the RF fields leads to a desire for maximum overdrive capability in those same generators in order to respond quickly to disturbances of the accelerator fields

  3. Low Duty-Cycling MAC Protocol for Low Data-Rate Medical Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Chongqing Zhang

    2017-05-01

    Full Text Available Wireless body area networks (WBANs are severely energy constrained, and how to improve the energy efficiency so as to prolong the network lifetime as long as possible is one of the most important goals of WBAN research. Low data-rate WBANs are promising to cut down the energy consumption and extend the network lifetime. Considering the characteristics and demands of low data-rate WBANs, a low duty-cycling medium access control (MAC protocol is specially designed for this kind of WBAN in this paper. Longer superframes are exploited to cut down the energy consumed on the transmissions and receptions of redundant beacon frames. Insertion time slots are embedded into the inactive part of a superframe to deliver the frames and satisfy the quality of service (QoS requirements. The number of the data subsections in an insertion time slot can be adaptively adjusted so as to accommodate low data-rate WBANs with different traffic. Simulation results show that the proposed MAC protocol performs well under the condition of low data-rate monitoring traffic.

  4. An RF energy harvesting power management circuit for appropriate duty-cycled operation

    Science.gov (United States)

    Shirane, Atsushi; Ito, Hiroyuki; Ishihara, Noboru; Masu, Kazuya

    2015-04-01

    In this study, we present an RF energy harvesting power management unit (PMU) for battery-less wireless sensor devices (WSDs). The proposed PMU realizes a duty-cycled operation that is divided into the energy charging time and discharging time. The proposed PMU detects two types of timing, thus, the appropriate timing for the activation can be recognized. The activation of WSDs at the proper timing leads to energy efficient operation and stable wireless communication. The proposed PMU includes a hysteresis comparator (H-CMP) and an RF signal detector (RF-SD) to detect the timings. The proposed RF-SD can operate without the degradation of charge efficiency by reusing the RF energy harvester (RF-EH) and H-CMP. The PMU fabricated in a 180 nm Si CMOS demonstrated the charge operation using the RF signal at 915 MHz and the two types of timing detection with less than 124 nW in the charge phase. Furthermore, in the active phase, the PMU generates a 0.5 V regulated power supply from the charged energy.

  5. Generation of multiple analog pulses with different duty cycles within VME control system for ICRH Aditya system

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ramesh; Singh, Manoj; Jadav, H M; Misra, Kishor; Kulkarni, S V, E-mail: rjoshi@ipr.res.i [Institute for plasma research, Bhat, Gandhinagar- 382428 (India)

    2010-02-01

    Ion Cyclotron Resonance Heating (ICRH) is a promising heating method for a fusion device due to its localized power deposition profile, a direct ion heating at high density, and established technology for high RF power generation and transmission at low cost. Multiple analog pulse with different duty cycle in master of digital pulse for Data acquisition and Control system for steady state RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya to produce pre ionization and second analog pulse will produce heating. The control system software is based upon single digital pulse operation for RF source. It is planned to integrate multiple analog pulses with different duty cycle in master of digital pulse for Data acquisition and Control system for RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya tokamak. The task of RF ICRH DAC is to control and acquisition of all ICRH system operation with all control loop and acquisition for post analysis of data with java based tool. For pre ionization startup as well as heating experiments using multiple RF Power of different powers and duration. The experiment based upon the idea of using single RF generator to energize antenna inside the tokamak to radiate power twice, out of which first analog pulse will produce pre ionization and second analog pulse will produce heating. The whole system is based on standard client server technology using tcp/ip protocol. DAC Software is based on linux operating system for highly reliable, secure and stable system operation in failsafe manner. Client system is based on tcl/tk like toolkit for user interface with c/c++ like environment which is reliable programming languages widely used on stand alone system operation with server as vxWorks real time operating system like environment. The paper is focused on the Data acquisition and monitoring system software on Aditya RF ICRH System with analog pulses in slave mode with digital pulse in

  6. Generation of multiple analog pulses with different duty cycles within VME control system for ICRH Aditya system

    International Nuclear Information System (INIS)

    Joshi, Ramesh; Singh, Manoj; Jadav, H M; Misra, Kishor; Kulkarni, S V

    2010-01-01

    Ion Cyclotron Resonance Heating (ICRH) is a promising heating method for a fusion device due to its localized power deposition profile, a direct ion heating at high density, and established technology for high RF power generation and transmission at low cost. Multiple analog pulse with different duty cycle in master of digital pulse for Data acquisition and Control system for steady state RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya to produce pre ionization and second analog pulse will produce heating. The control system software is based upon single digital pulse operation for RF source. It is planned to integrate multiple analog pulses with different duty cycle in master of digital pulse for Data acquisition and Control system for RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya tokamak. The task of RF ICRH DAC is to control and acquisition of all ICRH system operation with all control loop and acquisition for post analysis of data with java based tool. For pre ionization startup as well as heating experiments using multiple RF Power of different powers and duration. The experiment based upon the idea of using single RF generator to energize antenna inside the tokamak to radiate power twice, out of which first analog pulse will produce pre ionization and second analog pulse will produce heating. The whole system is based on standard client server technology using tcp/ip protocol. DAC Software is based on linux operating system for highly reliable, secure and stable system operation in failsafe manner. Client system is based on tcl/tk like toolkit for user interface with c/c++ like environment which is reliable programming languages widely used on stand alone system operation with server as vxWorks real time operating system like environment. The paper is focused on the Data acquisition and monitoring system software on Aditya RF ICRH System with analog pulses in slave mode with digital pulse in

  7. Generation of multiple analog pulses with different duty cycles within VME control system for ICRH Aditya system

    Science.gov (United States)

    Joshi, Ramesh; Singh, Manoj; Jadav, H. M.; Misra, Kishor; Kulkarni, S. V.; ICRH-RF Group

    2010-02-01

    Ion Cyclotron Resonance Heating (ICRH) is a promising heating method for a fusion device due to its localized power deposition profile, a direct ion heating at high density, and established technology for high RF power generation and transmission at low cost. Multiple analog pulse with different duty cycle in master of digital pulse for Data acquisition and Control system for steady state RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya to produce pre ionization and second analog pulse will produce heating. The control system software is based upon single digital pulse operation for RF source. It is planned to integrate multiple analog pulses with different duty cycle in master of digital pulse for Data acquisition and Control system for RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya tokamak. The task of RF ICRH DAC is to control and acquisition of all ICRH system operation with all control loop and acquisition for post analysis of data with java based tool. For pre ionization startup as well as heating experiments using multiple RF Power of different powers and duration. The experiment based upon the idea of using single RF generator to energize antenna inside the tokamak to radiate power twise, out of which first analog pulse will produce pre ionization and second analog pulse will produce heating. The whole system is based on standard client server technology using tcp/ip protocol. DAC Software is based on linux operating system for highly reliable, secure and stable system operation in failsafe manner. Client system is based on tcl/tk like toolkit for user interface with c/c++ like environment which is reliable programming languages widely used on stand alone system operation with server as vxWorks real time operating system like environment. The paper is focused on the Data acquisition and monitoring system software on Aditya RF ICRH System with analog pulses in slave mode with digital pulse in

  8. Distributed photovoltaic architecture powering a DC bus: Impact of duty cycle and load variations on the efficiency of the generator

    Science.gov (United States)

    Allouache, Hadj; Zegaoui, Abdallah; Boutoubat, Mohamed; Bokhtache, Aicha Aissa; Kessaissia, Fatma Zohra; Charles, Jean-Pierre; Aillerie, Michel

    2018-05-01

    This paper focuses on a photovoltaic generator feeding a load via a boost converter in a distributed PV architecture. The principal target is the evaluation of the efficiency of a distributed photovoltaic architecture powering a direct current (DC) PV bus. This task is achieved by outlining an original way for tracking the Maximum Power Point (MPP) taking into account load variations and duty cycle on the electrical quantities of the boost converter and on the PV generator output apparent impedance. Thereafter, in a given sized PV system, we analyze the influence of the load variations on the behavior of the boost converter and we deduce the limits imposed by the load on the DC PV bus. The simultaneous influences of 1- the variation of the duty cycle of the boost converter and 2- the load power on the parameters of the various components of the photovoltaic chain and on the boost performances are clearly presented as deduced by simulation.

  9. Duty cycle dependence of a periodically poled LiNbO3-based electro-optic Solc filter.

    Science.gov (United States)

    Rabia, Eyal; Arie, Ady

    2006-01-20

    We demonstrate that the performance of a periodically poled LiNbO3- (PPLN-) based electro-optic Solc filter is dependent on the duty cycle of the crystal. This may limit the performance of the device for applications such as add-drop filtering and switching, owing to the deterioration of the extinction ratio. It is shown that by adding a retarder to the Solc filter it is possible to improve the extinction ratio; thus the dependence of the filter on the duty cycle can be reduced. Using Jones calculus, we analyzed the effect of a variable retarder that can also be rotated on the extinction ratio. We experimentally observed a 6 dB increase in the extinction ratio when we used a half-wavelength retarder.

  10. DC motor operation controlled from a DC/DC power converter in pulse mode with low duty cycle

    OpenAIRE

    Stefanov, Goce; Kukuseva, Maja; Citkuseva Dimitrovska, Biljana

    2016-01-01

    In this paper pulse mode of operation of DC motor controlled by DC/DC power converter is analyzed. DC motor operation with time intervals in which the motor operates without output load is of interest. In this mode it is possible the motor to restore energy. Also, in the paper are represented calculations for the amount of the restored energy in the pulse mode operation of the motor for different duty cycles.

  11. Modeling and Analysis of Energy Conservation Scheme Based on Duty Cycling in Wireless Ad Hoc Sensor Network

    Science.gov (United States)

    Chung, Yun Won; Hwang, Ho Young

    2010-01-01

    In sensor network, energy conservation is one of the most critical issues since sensor nodes should perform a sensing task for a long time (e.g., lasting a few years) but the battery of them cannot be replaced in most practical situations. For this purpose, numerous energy conservation schemes have been proposed and duty cycling scheme is considered the most suitable power conservation technique, where sensor nodes alternate between states having different levels of power consumption. In order to analyze the energy consumption of energy conservation scheme based on duty cycling, it is essential to obtain the probability of each state. In this paper, we analytically derive steady state probability of sensor node states, i.e., sleep, listen, and active states, based on traffic characteristics and timer values, i.e., sleep timer, listen timer, and active timer. The effect of traffic characteristics and timer values on the steady state probability and energy consumption is analyzed in detail. Our work can provide sensor network operators guideline for selecting appropriate timer values for efficient energy conservation. The analytical methodology developed in this paper can be extended to other energy conservation schemes based on duty cycling with different sensor node states, without much difficulty. PMID:22219676

  12. Modeling and Analysis of Energy Conservation Scheme Based on Duty Cycling in Wireless Ad Hoc Sensor Network

    Directory of Open Access Journals (Sweden)

    Yun Won Chung

    2010-06-01

    Full Text Available In sensor network, energy conservation is one of the most critical issues since sensor nodes should perform a sensing task for a long time (e.g., lasting a few years but the battery of them cannot be replaced in most practical situations. For this purpose, numerous energy conservation schemes have been proposed and duty cycling scheme is considered the most suitable power conservation technique, where sensor nodes alternate between states having different levels of power consumption. In order to analyze the energy consumption of energy conservation scheme based on duty cycling, it is essential to obtain the probability of each state. In this paper, we analytically derive steady state probability of sensor node states, i.e., sleep, listen, and active states, based on traffic characteristics and timer values, i.e., sleep timer, listen timer, and active timer. The effect of traffic characteristics and timer values on the steady state probability and energy consumption is analyzed in detail. Our work can provide sensor network operators guideline for selecting appropriate timer values for efficient energy conservation. The analytical methodology developed in this paper can be extended to other energy conservation schemes based on duty cycling with different sensor node states, without much difficulty.

  13. Spanish experience of fuel performance under zinc injection conditions in high duty plants

    International Nuclear Information System (INIS)

    Sanchez, Alicia; Doncel, Nuria

    2008-01-01

    Zinc is being added to the reactor coolant system in three Spanish PWRs (Vandellos II, Asco I and Asco II), owned by Association Nuclear Asco Vandellos AIE (ANAV), to delay Primary Water Stress Corrosion Cracking (PWSCC) initiation. Although additional advantages from zinc addition are expected, in the short term some concern exists concerning fuel performance during the first cycles of zinc addition due to a possible elevation of corrosion products from system materials when zinc is initially added. Elevated corrosion product levels in a high duty plant may cause an enhancement on crud deposited on fuel, increasing Axial Offset Anomaly (AOA) risk and accelerated cladding corrosion. To demonstrate the acceptable performance of ZIRLOTM clad fuel under zinc chemistry at a high duty plant, EPRI's Fuel Reliability Program (FRP) has chosen Vandellos II as a zinc demonstration plant to perform oxide thickness measurements and crud scraping and analysis. This paper presents the results from Vandellos II and Asco II oxide measurements as well as the conclusions from the crud samples analyses performed at Vandellos II. Furthermore, the effect of zinc addition on corrosion product behavior and dose rates are be discussed

  14. High duty factor plasma generator for CERN's Superconducting Proton Linac.

    Science.gov (United States)

    Lettry, J; Kronberger, M; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, J-M; Küchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-02-01

    CERN's Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN's PS-Booster. Its ion source is a noncesiated rf driven H(-) volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H(-) during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the Large Hadron Collider. It consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H(-) during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H(-) plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the required heat dissipation and maintains the original functionality. Materials with higher thermal conductivity are selected and, wherever possible, thermal barriers resulting from low pressure contacts are removed by brazing metals on insulators. The AlN plasma chamber cooling circuit is inspired from the approach chosen for the cesiated high duty factor rf H(-) source operating at SNS.

  15. High duty factor structures for e+e- storage rings

    International Nuclear Information System (INIS)

    Allen, M.A.; Karvonen, L.G.

    1976-01-01

    The next generation of e + e - storage rings will need rf systems similar to those required for a continuous-duty linac of over 50 MeV. For the PEP Storage Ring at 18 GeV, it is presently planned to provide a peak accelerating voltage of 77 MV in 18 aluminum accelerating structures, each structure consisting of five slot-coupled cells operating in the π mode. The power dissipation will be 100 kW per cell for a total of 500 kW per five-cell structure at 353 MHz. A two-cell model was designed and built to dissipate 100 kW per cell or a total of 200 kW. This structure was powered (cw) to over 100 kW per cell, and detailed calorimetric data were taken and compared with the original heat transfer calculations. The power level achieved corresponds to a peak accelerating field (transit-time factor included) in the two-cell model of 0.8 MV per cell or 1.9 MV/meter. Operating experience with the SPEAR five-cell structure is discussed. The four SPEAR structures are each designed to operate with wall losses of 75 kW and up to 50 kW into the stored beam. Power to each structure is provided by a 125-kW high-efficiency four-cavity klystron. No isolation has been used and the resulting interaction between the accelerating structures, klystrons, and the stored beams is discussed

  16. Analysis of the backpressure effect of an Organic Rankine Cycle (ORC) evaporator on the exhaust line of a turbocharged heavy duty diesel power generator for marine applications

    International Nuclear Information System (INIS)

    Michos, Constantine N.; Lion, Simone; Vlaskos, Ioannis; Taccani, Rodolfo

    2017-01-01

    Highlights: • Waste heat recovery on internal combustion engines is studied. • The backpressure effect of the Organic Rankine Cycle boiler has been evaluated. • Three different state-of-the art turbocharging technologies have been assessed. • Six different fluids for medium-high temperature recovery have been considered. • A reduction up to 10% in fuel consumption can be achieved. - Abstract: In marine and power generation sectors, waste heat recovery technologies are attracting growing attention in order to increase heavy duty diesel engines efficiency and decrease fuel consumption, with the purpose of respecting stringent emissions legislations. In this work, the backpressure effect of an Organic Rankine Cycle (ORC) evaporator on the exhaust line of a turbocharged, V12 heavy duty diesel engine, for typical marine and power generation applications has been investigated using the commercial software Ricardo WAVE. Three different state-of-the art turbocharging strategies are assessed in order to counterbalance the increased pumping losses of the engine due to the boiler installation: fixed turbine, Waste-Gate (WG) and Variable Geometry Turbine (VGT). At the same time, the steady-state thermodynamic performance of two different ORC configurations, simple tail-pipe evaporator and recuperated simple tail-pipe evaporator layouts, are assessed, with the scope of further increasing the engine power output, recovering unutilized exhaust gas heat. Several different working fluids, suitable for medium-high temperature waste heat recovery, are evaluated and screened, considering, as well, health and safety issues. Thermodynamic cycle parameters such as, for example, evaporation and condensing pressures, working fluid mass flow and cycle temperatures, are optimized in order to obtain the maximum improvement in Brake Specific Fuel Consumption (bsfc). From the engine side point of view, a VGT turbocharger is the most favorable solution to withstand increased

  17. Computer simulation of the heavy-duty turbo-compounded diesel cycle for studies of engine efficiency and performance

    Science.gov (United States)

    Assanis, D. N.; Ekchian, J. A.; Heywood, J. B.; Replogle, K. K.

    1984-01-01

    Reductions in heat loss at appropriate points in the diesel engine which result in substantially increased exhaust enthalpy were shown. The concepts for this increased enthalpy are the turbocharged, turbocompounded diesel engine cycle. A computer simulation of the heavy duty turbocharged turbo-compounded diesel engine system was undertaken. This allows the definition of the tradeoffs which are associated with the introduction of ceramic materials in various parts of the total engine system, and the study of system optimization. The basic assumptions and the mathematical relationships used in the simulation of the model engine are described.

  18. DC-pulsed voltage electrochemical method based on duty cycle self-control for producing TERS gold tips

    International Nuclear Information System (INIS)

    Vasilchenko, V E; Kharintsev, S S; Salakhov, M Kh

    2013-01-01

    This paper presents a modified dc-pulsed low voltage electrochemical method in which a duty cycle is self tuned while etching. A higher yield of gold tips suitable for performing tip-enhanced Raman scattering (TERS) measurements is demonstrated. The improvement is caused by the self-control of the etching rate along the full surface of the tip. A capability of the gold tips to enhance a Raman signal is exemplified by TERS spectroscopy of single walled carbon nanotubes bundle, sulfur and vanadium oxide

  19. 40 CFR 86.099-10 - Emission standards for 1999 and later model year Otto-cycle heavy-duty engines and vehicles.

    Science.gov (United States)

    2010-07-01

    ... model year Otto-cycle heavy-duty engines and vehicles. 86.099-10 Section 86.099-10 Protection of... to Otto-cycle engines used in such MDPVs, except as specified in subpart S of this part. The term... AND IN-USE HIGHWAY VEHICLES AND ENGINES General Provisions for Emission Regulations for 1977 and Later...

  20. Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

    Directory of Open Access Journals (Sweden)

    Baofeng Yao

    2014-11-01

    Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

  1. Life cycle air emissions impacts and ownership costs of light-duty vehicles using natural gas as a primary energy source.

    Science.gov (United States)

    Luk, Jason M; Saville, Bradley A; MacLean, Heather L

    2015-04-21

    This paper aims to comprehensively distinguish among the merits of different vehicles using a common primary energy source. In this study, we consider compressed natural gas (CNG) use directly in conventional vehicles (CV) and hybrid electric vehicles (HEV), and natural gas-derived electricity (NG-e) use in plug-in battery electric vehicles (BEV). This study evaluates the incremental life cycle air emissions (climate change and human health) impacts and life cycle ownership costs of non-plug-in (CV and HEV) and plug-in light-duty vehicles. Replacing a gasoline CV with a CNG CV, or a CNG CV with a CNG HEV, can provide life cycle air emissions impact benefits without increasing ownership costs; however, the NG-e BEV will likely increase costs (90% confidence interval: $1000 to $31 000 incremental cost per vehicle lifetime). Furthermore, eliminating HEV tailpipe emissions via plug-in vehicles has an insignificant incremental benefit, due to high uncertainties, with emissions cost benefits between -$1000 and $2000. Vehicle criteria air contaminants are a relatively minor contributor to life cycle air emissions impacts because of strict vehicle emissions standards. Therefore, policies should focus on adoption of plug-in vehicles in nonattainment regions, because CNG vehicles are likely more cost-effective at providing overall life cycle air emissions impact benefits.

  2. Lithium-Ion Battery Cell Cycling and Usage Analysis in a Heavy-Duty Truck Field Study

    Directory of Open Access Journals (Sweden)

    Pontus Svens

    2015-05-01

    Full Text Available This paper presents results from a field test performed on commercial power-optimized lithium-ion battery cells cycled on three heavy-duty trucks. The goal with this study was to age battery cells in a hybrid electric vehicle (HEV environment and find suitable methods for identifying cell ageing. The battery cells were cycled on in-house developed equipment intended for testing on conventional vehicles by emulating an HEV environment. A hybrid strategy that allows battery usage to vary within certain limits depending on driving patterns was used. This concept allows unobtrusive and low-cost testing of battery cells under realistic conditions. Each truck was equipped with one cell cycling equipment and two battery cells. One cell per vehicle was cycled during the test period while a reference cell on each vehicle experienced the same environmental conditions without being cycled. Differential voltage analysis and electrochemical impedance spectroscopy were used to identify ageing of the tested battery cells. Analysis of driving patterns and battery usage was performed from collected vehicle data and battery cell data.

  3. A high-gradient high-duty-factor Rf photo-cathode electron gun

    International Nuclear Information System (INIS)

    Rimmer, Robert A.; Hartman, Neal; Lidia, Steven M.; Wang, Shaoheng

    2002-01-01

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure

  4. A high-gradient high-duty-factor RF photo-cathode electron gun

    International Nuclear Information System (INIS)

    Rimmer, Robert; Hartman, N.; Lidia, S.; Wang, S.H.

    2002-01-01

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure

  5. Dynamic behavior of Rankine cycle system for waste heat recovery of heavy duty diesel engines under driving cycle

    International Nuclear Information System (INIS)

    Xie, Hui; Yang, Can

    2013-01-01

    Highlights: • Waste heat recovery behavior of the RCS during driving cycle was investigated. • Four operating modes were defined to describe the operating process of the RCS under driving cycle. • The operating mode switching is the crucial reason for on-road inefficiency. • The dry and isentropic fluids are superior to the wet ones on the adaptability to unsteady ExGE. • The effects of the vapor parameters on RCT-E and power mode percentage are opposite. - Abstract: The RCS (Rankine cycle system) used to recover the WHE (waste heat energy) from engines has been regarded as one of the most potential ways of achieving higher efficiency. However, it is of great challenge to keep the RCS still in good performance under driving cycle. This paper tries to reveal and explain its on-road inefficiency. The operating process of the RCS under driving cycle was analyzed in advance. Afterwards, four basic operating modes were defined, including startup mode, turbine turning mode, power mode and protection mode. Then, a RCS model was established and operating performances of the RCS under an actual driving cycle were discussed based on this model. The results indicate that the on-road RCS-E (Rankine cycle system efficiency) is as low as 3.63%, which is less than half of the design RCS-E (7.77%) at the rated operating point. Despite the inevitable vapor state fluctuation, it is the operating mode switching during the driving cycle that leads to the on-road inefficiency. Further investigations indicate that the expander safety temperature and its safety margin affected by the working fluids, designed superheat degree and evaporating pressure are the main factors determining the operating mode switching. Finally, the effects of the working fluids, designed superheat degree and evaporating pressure on the operating mode switching and RC (Rankine cycle) efficiencies were profoundly investigated. The study shows that the dry and isentropic fluids are superior to the wet

  6. The Grumman/Brookhaven high-brightness, high-duty factor RF gun

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Birnbaum, I.A.; Cole, M.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Waren, G.D.

    1992-01-01

    Under a joint collaboration between Brookhaven National Laboratory and the Grumman Corporation, a high-duty (>1%) photocathode RF gun is under construction for use at the ATF facility at BNL. The gun will be capable of producing short ( 300 A (after compression) and a total bunch charge in excess of 3 nC. The gun consists of 3-1/2 cells constructed from GlidCop, an alumina dispersion strengthened copper alloy. Two individually phased waveguides are used to power the first two and final two cells. (Author) 10 refs., 8 figs., 2 tabs

  7. 77 FR 37377 - High Pressure Steel Cylinders From the People's Republic of China: Antidumping Duty Order

    Science.gov (United States)

    2012-06-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... Department is issuing an antidumping duty order on high pressure steel cylinders from the People's Republic... determination of material injury to a U.S. industry.\\1\\ \\1\\ See High Pressure Steel Cylinders from China...

  8. 77 FR 37384 - High Pressure Steel Cylinders From the People's Republic of China: Countervailing Duty Order

    Science.gov (United States)

    2012-06-21

    ... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel...''), the Department is issuing a countervailing duty order on high pressure steel cylinders (``steel... investigation of steel cylinders from the PRC. See High Pressure Steel Cylinders From the People's Republic of...

  9. Very high cycle fatigue testing of concrete using ultrasonic cycling

    Energy Technology Data Exchange (ETDEWEB)

    Karr, Ulrike; Schuller, Reinhard; Fitzka, Michael; Mayer, Herwig [Univ. of Natural Resources and Life Sciences, Vienna (Austria). Inst. of Physics and Materials Science; Denk, Andreas; Strauss, Alfred [Univ. of Natural Resources and Life Sciences, Vienna (Austria)

    2017-06-01

    The ultrasonic fatigue testing method has been further developed to perform cyclic compression tests with concrete. Cylindrical specimens vibrate in resonance at a frequency of approximately 20 kHz with superimposed compressive static loads. The high testing frequency allows time-saving investigations in the very high cycle fatigue regime. Fatigue tests were carried out on ''Concrete 1'' (compressive strength f{sub c} = 80 MPa) and ''Concrete 2'' (f{sub c} = 107 MPa) under purely compressive loading conditions. Experiments at maximum compressive stresses of 0.44 f{sub c} (Concrete 1) and 0.38 f{sub c} (Concrete 2) delivered specimen failures above 109 cycles, indicating that no fatigue limit exists for concrete below one billion load cycles. Resonance frequency, power required to resonate the specimen and second order harmonics of the vibration are used to monitor fatigue damage in situ. Specimens were scanned by X-ray computed tomography prior to and after testing. Fatigue cracks were produced by ultrasonic cycling in the very high cycle fatigue regime at interfaces of grains as well as in cement. The possibilities as well as limitations of ultrasonic fatigue testing of concrete are discussed.

  10. Order of 28 March 1980 on the transfer to ENUSA of duties of the Junta de Energia Nuclear connected with the nuclear fuel cycle

    International Nuclear Information System (INIS)

    1980-01-01

    In implementation of the Royal Decree of 7 December 1979 the Minister of Industry and Energy made this Order regulating the transfer to ENUSA (National Uranium Undertaking) of the Junta de Energia Nuclear's duties relating to the nuclear fuel cycle. The Order sets up, within the Ministry of Industry and Energy, a Transfer Commission responsible for establishing the directives prior to the measures to be taken by the Ministry concerning the transfer to ENUSA of the duties, personnel and establishments of the Junta connected with the nuclear fuel cycle. It will also determine the dates of such transfer, according to the order of priority laid down in the Order. (NEA) [fr

  11. Diffraction study of duty-cycle error in ferroelectric quasi-phase-matching gratings with Gaussian beam illumination

    Science.gov (United States)

    Dwivedi, Prashant Povel; Kumar, Challa Sesha Sai Pavan; Choi, Hee Joo; Cha, Myoungsik

    2016-02-01

    Random duty-cycle error (RDE) is inherent in the fabrication of ferroelectric quasi-phase-matching (QPM) gratings. Although a small RDE may not affect the nonlinearity of QPM devices, it enhances non-phase-matched parasitic harmonic generations, limiting the device performance in some applications. Recently, we demonstrated a simple method for measuring the RDE in QPM gratings by analyzing the far-field diffraction pattern obtained by uniform illumination (Dwivedi et al. in Opt Express 21:30221-30226, 2013). In the present study, we used a Gaussian beam illumination for the diffraction experiment to measure noise spectra that are less affected by the pedestals of the strong diffraction orders. Our results were compared with our calculations based on a random grating model, demonstrating improved resolution in the RDE estimation.

  12. Comparison of life cycle greenhouse gases from natural gas pathways for medium and heavy-duty vehicles.

    Science.gov (United States)

    Tong, Fan; Jaramillo, Paulina; Azevedo, Inês M L

    2015-06-16

    The low-cost and abundant supply of shale gas in the United States has increased the interest in using natural gas for transportation. We compare the life cycle greenhouse gas (GHG) emissions from different natural gas pathways for medium and heavy-duty vehicles (MHDVs). For Class 8 tractor-trailers and refuse trucks, none of the natural gas pathways provide emissions reductions per unit of freight-distance moved compared to diesel trucks. When compared to the petroleum-based fuels currently used in these vehicles, CNG and centrally produced LNG increase emissions by 0-3% and 2-13%, respectively, for Class 8 trucks. Battery electric vehicles (BEVs) powered with natural gas-produced electricity are the only fuel-technology combination that achieves emission reductions for Class 8 transit buses (31% reduction compared to the petroleum-fueled vehicles). For non-Class 8 trucks (pick-up trucks, parcel delivery trucks, and box trucks), BEVs reduce emissions significantly (31-40%) compared to their diesel or gasoline counterparts. CNG and propane achieve relatively smaller emissions reductions (0-6% and 19%, respectively, compared to the petroleum-based fuels), while other natural gas pathways increase emissions for non-Class 8 MHDVs. While using natural gas to fuel electric vehicles could achieve large emission reductions for medium-duty trucks, the results suggest there are no great opportunities to achieve large emission reductions for Class 8 trucks through natural gas pathways with current technologies. There are strategies to reduce the carbon footprint of using natural gas for MHDVs, ranging from increasing vehicle fuel efficiency, reducing life cycle methane leakage rate, to achieving the same payloads and cargo volumes as conventional diesel trucks.

  13. 76 FR 28807 - High Pressure Steel Cylinders From China; Institution of Antidumping and Countervailing Duty...

    Science.gov (United States)

    2011-05-18

    ... the United States is materially retarded, by reason of imports from China of High Pressure Steel... INTERNATIONAL TRADE COMMISSION [Investigation Nos. 701-TA-480 and 731-TA-1188 (Preliminary)] High Pressure Steel Cylinders From China; Institution of Antidumping and Countervailing Duty Investigations and...

  14. High conversion HTRs and their fuel cycle

    International Nuclear Information System (INIS)

    Gutmann, H.; Hansen, U.; Larsen, H.; Price, M.S.T.

    1975-01-01

    This report discusses the principles of the core design and the fuel cycle layout for High Conversion HTRs (HCHTRs). Though most of the principles apply equally to HTRs of the pebble-bed and the prismatic fuel element design types, the paper concentrates on the latter. Design and fuel cycle strategies for the full utilisation of the high conversion potential are compared with others that aim at easier reprocessing and the 'environmental' fuel cycle. The paper concludes by discussing operating and fuel cycle characteristics and economics of HCHTRs, and how the latter impinge on the allowable price for uranium ore and the available uranium resources. (orig./UA) [de

  15. Impact of organic Rankine cycle system installation on light duty vehicle considering both positive and negative aspects

    International Nuclear Information System (INIS)

    Usman, Muhammad; Imran, Muhammad; Yang, Youngmin; Park, Byung-Sik

    2016-01-01

    Highlights: • Positive and negative effects of waste heat recovery unit on vehicle were studied. • Organic Rankine cycle based power system for waste heat recovery. • Relationship of ORC unit weight and power was developed. • Impact of added weight, Part load operation and back pressure are presented. • Power enhancement of 5.82% of engine when positive & negative effects considered. - Abstract: This paper presents the analysis of organic Rankine cycle (ORC) based waste heat recovery system. Both the positive and negative effects of ORC system installation on a light duty vehicle were evaluated. Engine exhaust data for a light duty vehicle was used to design an ORC based system. Optimum cycle design suggests that ORC system installation is feasible. Results presented that for the vehicle operation at 100 km/h, engine power can be enhanced by 10.88% which is 5.92 kW of additional power and at the lower speed of 23.5 km/h, the engine power enhancement was 2.34%. ORC component weight data from manufacturers were used to estimate the weight of the designed system. The performance decline due to added weight is calculated. Effects of added back pressure and performance decline due to the part-load operation of ORC unit were also calculated and an overall effect of waste heat recovery system was evaluated. The results then suggested that maximum power enhancement is 5.82% at the vehicle speed of 100 km/h instead of previously mentioned 10.88% can be achieved if negative effects are also considered. Furthermore, it was concluded that at speeds lower than 48 km/h the waste heat recovery system was not beneficial at all and low-speed operation was in fact not preferable as it results in additional power demand from the engine by 6.39% at 23.5 km/h. The vehicles for city driving cycles are not recommended for ORC installation. Another finding revealed that if exhaust heat recovery heat exchanger is designed for maximum heat recovery, at part load operation, the

  16. Battery Dimensioning and Life Cycle Costs Analysis for a Heavy-Duty Truck Considering the Requirements of Long-Haul Transportation

    Directory of Open Access Journals (Sweden)

    Ivan Mareev

    2017-12-01

    Full Text Available The use of heavy-duty battery electric trucks for long-haul transportation is challenging because of the required high energy amounts and thus the high capacity of traction batteries. Furthermore a high capacity battery implies high initial costs for the electric vehicle. This study investigates the required battery capacity for battery electric trucks considering the requirements of long-haul transportation in Germany and compares the life cycle costs of battery electric trucks and conventional diesel trucks in different transportation scenarios. The average consumption is simulated for different battery electric truck configurations on the main German highways and transportation scenarios incorporating battery charging during driver rest periods. The results show that in average case the required battery would restrict the payload to only 80% of a usual diesel truck payload that might be acceptable considering the statistical payload use. The life cycle costs in the examined scenarios also considering the charging infrastructure show that battery electric trucks can already perform on the same costs level as diesel trucks in certain scenarios.

  17. Lifecycle comparison of selected Li-ion battery chemistries under grid and electric vehicle duty cycle combinations

    Science.gov (United States)

    Crawford, Alasdair J.; Huang, Qian; Kintner-Meyer, Michael C. W.; Zhang, Ji-Guang; Reed, David M.; Sprenkle, Vincent L.; Viswanathan, Vilayanur V.; Choi, Daiwon

    2018-03-01

    Li-ion batteries are expected to play a vital role in stabilizing the electrical grid as solar and wind generation capacity becomes increasingly integrated into the electric infrastructure. This article describes how two different commercial Li-ion batteries based on LiNi0.8Co0.15Al0.05O2 (NCA) and LiFePO4 (LFP) chemistries were tested under grid duty cycles recently developed for two specific grid services: (1) frequency regulation (FR) and (2) peak shaving (PS) with and without being subjected to electric vehicle (EV) drive cycles. The lifecycle comparison derived from the capacity, round-trip efficiency (RTE), resistance, charge/discharge energy, and total used energy of the two battery chemistries are discussed. The LFP chemistry shows better stability for the energy-intensive PS service, while the NCA chemistry is more conducive to the FR service under the operating regimes investigated. The results can be used as a guideline for selection, deployment, operation, and cost analyses of Li-ion batteries used for different applications.

  18. Heavy-duty high-repetition-rate generators

    NARCIS (Netherlands)

    Heesch, van E.J.M.; Yan, K.; Pemen, A.J.M.

    2002-01-01

    We present our results on high-power repetitive pulse sources for continuous operation. Two 1-10-kW systems using advanced spark gap technology and a transmission line transformer have been tested for several hundred hours at a 60-MW pulse level. High reliability and above 90% overall efficiency are

  19. Development of real-world driving cycles and estimation of emission factors for in-use light-duty gasoline vehicles in urban areas.

    Science.gov (United States)

    Hwa, Mei-Yin; Yu, Tai-Yi

    2014-07-01

    This investigation adopts vehicle tracking manner to establish real-world driving patterns and estimates emission factors with dynamometers with 23 traffic-driving variables for 384 in-use light-duty passenger vehicles during non-rush hour. Adequate numbers of driving variables were decided with factor analysis and cluster analysis. The dynamometer tests were performed on FTP75 cycle and five local driving cycles derived from real-world speed profiles. Results presented that local driving cycles and FTP75 cycle were completely different in driving characteristic parameters of typical driving cycles and emission factors. The highest values of emission factor ratios of local driving cycle and FTP75 cycle for CO, NMHC, NO x , CH4, and CO2 were 1.38, 1.65, 1.58, 1.39, and 1.14, respectively.

  20. Evaluation of Highly Realistic Training for Independent Duty Corpsmen Students

    Science.gov (United States)

    2015-05-21

    that he or she can perform desired actions or behaviors ( Bandura , 1977). In the present study, three types of self-efficacy were assessed: general...such as resilience. IDC Highly Realistic Training 10 REFERENCES Bandura , A (1977). Self-efficacy: Toward a unifying theory of behavioral

  1. 76 FR 33213 - High Pressure Steel Cylinders from the People's Republic of China: Initiation of Antidumping Duty...

    Science.gov (United States)

    2011-06-08

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977)] High Pressure Steel... (``Department'') received a petition concerning imports of high pressure steel cylinders (``steel cylinders...\\ (``Petitioner''). See Petitions for the Imposition of Antidumping and Countervailing Duties: High Pressure Steel...

  2. Energy conversion efficiency of hybrid electric heavy-duty vehicles operating according to diverse drive cycles

    Energy Technology Data Exchange (ETDEWEB)

    Banjac, Titina [AVL-AST d.o.o., Trg Leona Stuklja 5, SI-2000 Maribor (Slovenia); Trenc, Ferdinand; Katrasnik, Tomaz [Faculty of Mechanical Engineering, Univ. of Ljubljana, Askerceva 6, SI-1000 Ljubljana (Slovenia)

    2009-12-15

    Energy consumption and exhaust emissions of hybrid electric vehicles (HEVs) strongly depend on the HEV topology, power ratios of their components and applied control strategy. Combined analytical and simulation approach was applied to analyze energy conversion efficiency of different HEV topologies. Analytical approach is based on the energy balance equations and considers all energy paths in the HEVs from the energy sources to the wheels and to other energy sinks. Simulation approach is based on a fast forward-facing simulation model for simulating parallel and series HEVs as well as for conventional internal combustion engine vehicles, and considers all components relevant for modeling energy conversion phenomena. Combined approach enables evaluation of energy losses on different energy paths and provides their impact on the fuel economy. It therefore enables identification of most suitable HEV topology and of most suitable power ratios of the components for targeted vehicle application, since it reveals and quantifies the mechanisms that could lead to improved energy conversion efficiency of particular HEV. The paper exposes characteristics of the test cycles that lead to improved energy conversion efficiency of HEVs. Mechanisms leading to improved fuel economy of parallel HEVs through drive-away and vehicle propulsion at low powertrain loads by electric motor are also analyzed. It was also shown that control strategies managing energy flow through electric storage devices significantly influence energy conversion efficiency of series HEVs. (author)

  3. Total fuel-cycle analysis of heavy-duty vehicles using biofuels and natural gas-based alternative fuels.

    Science.gov (United States)

    Meyer, Patrick E; Green, Erin H; Corbett, James J; Mas, Carl; Winebrake, James J

    2011-03-01

    Heavy-duty vehicles (HDVs) present a growing energy and environmental concern worldwide. These vehicles rely almost entirely on diesel fuel for propulsion and create problems associated with local pollution, climate change, and energy security. Given these problems and the expected global expansion of HDVs in transportation sectors, industry and governments are pursuing biofuels and natural gas as potential alternative fuels for HDVs. Using recent lifecycle datasets, this paper evaluates the energy and emissions impacts of these fuels in the HDV sector by conducting a total fuel-cycle (TFC) analysis for Class 8 HDVs for six fuel pathways: (1) petroleum to ultra low sulfur diesel; (2) petroleum and soyoil to biodiesel (methyl soy ester); (3) petroleum, ethanol, and oxygenate to e-diesel; (4) petroleum and natural gas to Fischer-Tropsch diesel; (5) natural gas to compressed natural gas; and (6) natural gas to liquefied natural gas. TFC emissions are evaluated for three greenhouse gases (GHGs) (carbon dioxide, nitrous oxide, and methane) and five other pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, particulate matter, and sulfur oxides), along with estimates of total energy and petroleum consumption associated with each of the six fuel pathways. Results show definite advantages with biodiesel and compressed natural gas for most pollutants, negligible benefits for e-diesel, and increased GHG emissions for liquefied natural gas and Fischer-Tropsch diesel (from natural gas).

  4. Life cycle air quality impacts of conventional and alternative light-duty transportation in the United States.

    Science.gov (United States)

    Tessum, Christopher W; Hill, Jason D; Marshall, Julian D

    2014-12-30

    Commonly considered strategies for reducing the environmental impact of light-duty transportation include using alternative fuels and improving vehicle fuel economy. We evaluate the air quality-related human health impacts of 10 such options, including the use of liquid biofuels, diesel, and compressed natural gas (CNG) in internal combustion engines; the use of electricity from a range of conventional and renewable sources to power electric vehicles (EVs); and the use of hybrid EV technology. Our approach combines spatially, temporally, and chemically detailed life cycle emission inventories; comprehensive, fine-scale state-of-the-science chemical transport modeling; and exposure, concentration-response, and economic health impact modeling for ozone (O3) and fine particulate matter (PM2.5). We find that powering vehicles with corn ethanol or with coal-based or "grid average" electricity increases monetized environmental health impacts by 80% or more relative to using conventional gasoline. Conversely, EVs powered by low-emitting electricity from natural gas, wind, water, or solar power reduce environmental health impacts by 50% or more. Consideration of potential climate change impacts alongside the human health outcomes described here further reinforces the environmental preferability of EVs powered by low-emitting electricity relative to gasoline vehicles.

  5. Prototype high current, high duty factor negative hydrogen ion source for LAMPF

    International Nuclear Information System (INIS)

    Lawrence, G.P.; Hayward, T.D.; Jackson, J.A.

    1975-01-01

    Present plans for the high current proton storage ring at LAMPF incorporate charge changing (stripping) injection of H - ions in all modes of operation. Achievable stored current levels in this device will be strongly dependent on the maximum H - beam intensity which can be accelerated by the linac, consistent with acceptable beam spill. This requirement has stimulated a program to develop an H - ion source capable of providing a suitably high peak current (up to 25 mA) at high duty factor (up to 12 percent), with a normalized x,x' or y,y' emittance acceptable to the accelerating system. There are presently two main approaches which could lead to H - ion sources providing this kind of performance. These are (a) the charge exchange method, in which an intense proton beam is fractionally converted to H - beam in a suitable charge adding medium, and (b) the direct extraction method, in which H - ions are obtained by a surface emission process associated with a gas discharge plasma. While both approaches may eventually find optimum application in different situations, it is not obvious, at present, which scheme will turn out to be the most satisfactory for LAMPF. A prototype charge exchange H - ion source has been constructed as a first step in the development program and is presently being evaluated. Work on surface emission direct extraction techniques is in the planning stages. (U.S.)

  6. A hybrid life cycle assessment of the vehicle-to-grid application in light duty commercial fleet

    International Nuclear Information System (INIS)

    Zhao, Yang; Tatari, Omer

    2015-01-01

    The vehicle-to-grid system is an approach utilizing the idle battery capacity of electric vehicles while they are parked to provide supplementary energy to the power grid. As electrification continues in light duty vehicle fleets, the application of vehicle-to-grid systems for commercial delivery truck fleets can provide extra revenue for fleet owners, and also has significant potential for reducing greenhouse gas emissions from the electricity generation sector. In this study, an economic input–output based hybrid life cycle assessment is conducted to analyze the potential greenhouse gas emissions emission savings from the use of the vehicle-to-grid system, as well as the possible emission impacts caused by battery degradation. A Monte Carlo simulation was performed to address the uncertainties that lie in the electricity exchange amount of the vehicle-to-grid service as well as the battery life of the electric vehicles. The results of this study showed that extended range electric vehicles and battery electric vehicles are both viable regulation service providers for saving greenhouse gas emissions from electricity generation if the battery wear-out from regulation services is assumed to be minimal, but the vehicle-to-grid system becomes less attractive at higher battery degradation levels. - Highlights: • The commercial delivery trucks are studied as vehicle-to-grid service providers. • Hybrid life cycle assessment is conducted to evaluate emission mitigation. • Battery degradation level and corresponding emissions and cost are evaluated. • Vehicle-to-grid service is shown to have significant emission saving effect.

  7. Investigation of CuInSe2 nanowire arrays with core-shell structure electrodeposited at various duty cycles into anodic alumina templates

    Science.gov (United States)

    Cheng, Yu-Song; Wang, Na-Fu; Tsai, Yu-Zen; Lin, Jia-Jun; Houng, Mau-Phon

    2017-02-01

    Copper indium selenide (CuInSe2) nanowire (NW) arrays were prepared at various electrolyte duty cycles by filling anodic alumina templates through the pulsed electrodeposition technique. X-ray diffraction and scanning electron microscopy (SEM) images showed that the nucleation mechanism of CuInSe2 NW arrays was affected by the electrodeposition duty cycle. Moreover, SEM images showed that the diameter and length of the NWs were 80 nm and 2 μm, respectively. Furthermore, PEDOT/CuInSe2 NW core-shell arrays were fabricated using surfactant-modified CuInSe2 NW surfaces showing the lotus effect. Transmission electron microscopy images confirmed that a core-shell structure was achieved. Current-voltage plots revealed that the CuInSe2 NW arrays were p-type semiconductors; moreover, the core-shell structure improved the diode ideality factor from 3.91 to 2.63.

  8. Design of a high-brightness, high-duty factor photocathode electron gun

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Birnbaum, I.A.; Fixler, S.Z.; Heuer, R.L.; Siddiqi, S.; Sheedy, E.; Ben-Zvi, I.; Batchelor, K.; Gallardo, J.C.; Kirk, H.G.; Srinivasan-Rao, T.; Warren, G.D.

    1991-09-01

    The proposed UV-FEL user's facility at Brookhaven National Laboratory will require a photocathode gun capable of producing short (< 6 psec) bunches of electrons in high repetition rates (5 kHz), low energy spread (< 1.5.%), a peak current of 300 A (after compression) and a total bunch charge of up to 2 nC. At the highest charge the normalized transverse emittance should be less than 7 π mm-mrad. We are presently designing a gun that is expected to exceed these requirements. This gun will consist of 3 1/2 cells, constructed of GlidCop-15, an aluminum oxide dispersion strengthened copper alloy. The gun will be capable of operating at duty factors in excess of 1%. Extensive beam dynamics studies of the gun were used to determine the effect of varying the length of the first cell, shaping the apertures between cells, and increasing the number of cells. In addition, a detailed thermal and mechanical study of the gun was performed to ensure that the thermal stresses were well within the allowable limits and that copper erosion of the water channels would not occur

  9. Japanese programme on the development of high duty fuel and related power ramping tests

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Y

    1983-06-01

    Power ramping tests hitherto planned or carried out in Japan can be classified into two categories: 1) the tests programme by private organizations on fuel behaviour under various conditions of power ramping, in participating international programmes; and 2) a partially government sponsored programme, which was officially inaugurated in 1981 under the title of High-Duty Fuel Development Programme. The latter has been carried out by the Nuclear Power Engineering Test Centre, based on the schedule decided by the MITI Committee (chaired by the author), for a period of 10 years. These programmes will be described with emphasis on the latter (National Programme). (author)

  10. RF control at transient beamloading for high-duty-factor linacs

    Energy Technology Data Exchange (ETDEWEB)

    Chernogubovsky, M.A.; Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-08-01

    An effective RF control with the transient beamloading is the major issue in the operation of the high-duty-factor linacs to suppress the undesirable beam loss. The RF control method is considered to obtain the control principle and the state equation, under the analysis of electrodynamical properties of the excitation in the resonator of the linac due to the transient beamloading. The concept of the directional selective coupling is applied for the RF system to define the main characteristics and to optimize the RF control parameters. (author)

  11. Japanese programme on the development of high duty fuel and related power ramping tests

    International Nuclear Information System (INIS)

    Mishima, Y.

    1983-01-01

    Power ramping tests hitherto planned or carried out in Japan can be classified into two categories: 1) the tests programme by private organizations on fuel behaviour under various conditions of power ramping, in participating international programmes; and 2) a partially government sponsored programme, which was officially inaugurated in 1981 under the title of High-Duty Fuel Development Programme. The latter has been carried out by the Nuclear Power Engineering Test Centre, based on the schedule decided by the MITI Committee (chaired by the author), for a period of 10 years. These programmes will be described with emphasis on the latter (National Programme). (author)

  12. 77 FR 3281 - High Pressure Steel Cylinders From China; Scheduling of the Final Phase of Countervailing Duty...

    Science.gov (United States)

    2012-01-23

    ...)] High Pressure Steel Cylinders From China; Scheduling of the Final Phase of Countervailing Duty and... retarded, by reason of subsidized and less-than-fair-value imports from China of high pressure steel... (``high pressure steel cylinders''). High pressure steel cylinders are fabricated of chrome alloy steel...

  13. Investigation of CuInSe{sub 2} nanowire arrays with core–shell structure electrodeposited at various duty cycles into anodic alumina templates

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yu-Song [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China); Wang, Na-Fu; Tsai, Yu-Zen [Department of Electronic Engineering, Cheng Shiu University, 840 Chengcing Rd., Niaosong District, Kaohsiung City 833, Taiwan (China); Lin, Jia-Jun [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China); Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, Tainan 701, Taiwan (China)

    2017-02-28

    Highlights: • The present paper reports that CuInSe2 NW arrays were fabricated through pulsed electrode position onto an AAO template with various duty cycles, and a pore-filling ratio of approximately 92% was achieved. • GIXRD patterns showed that all CuInSe2 NW arrays were chalcopyrite and SAED images confirmed that the CuInSe2 NWs were polycrystalline. • PEDOT/CuInSe2 NW core–shell arrays were fabricated using surfactant-modified CuInSe2 NW surfaces showing the lotus effect. • Current–voltage plots revealed that the CuInSe2 NW arrays were p-type semiconductors; moreover, the core–shell structure improved the diode ideality factor from 3.91 to 2.63. - Abstract: Copper indium selenide (CuInSe{sub 2}) nanowire (NW) arrays were prepared at various electrolyte duty cycles by filling anodic alumina templates through the pulsed electrodeposition technique. X-ray diffraction and scanning electron microscopy (SEM) images showed that the nucleation mechanism of CuInSe{sub 2} NW arrays was affected by the electrodeposition duty cycle. Moreover, SEM images showed that the diameter and length of the NWs were 80 nm and 2 μm, respectively. Furthermore, PEDOT/CuInSe{sub 2} NW core–shell arrays were fabricated using surfactant-modified CuInSe{sub 2} NW surfaces showing the lotus effect. Transmission electron microscopy images confirmed that a core–shell structure was achieved. Current–voltage plots revealed that the CuInSe{sub 2} NW arrays were p-type semiconductors; moreover, the core–shell structure improved the diode ideality factor from 3.91 to 2.63.

  14. Investigation of CuInSe2 nanowire arrays with core–shell structure electrodeposited at various duty cycles into anodic alumina templates

    International Nuclear Information System (INIS)

    Cheng, Yu-Song; Wang, Na-Fu; Tsai, Yu-Zen; Lin, Jia-Jun; Houng, Mau-Phon

    2017-01-01

    Highlights: • The present paper reports that CuInSe2 NW arrays were fabricated through pulsed electrode position onto an AAO template with various duty cycles, and a pore-filling ratio of approximately 92% was achieved. • GIXRD patterns showed that all CuInSe2 NW arrays were chalcopyrite and SAED images confirmed that the CuInSe2 NWs were polycrystalline. • PEDOT/CuInSe2 NW core–shell arrays were fabricated using surfactant-modified CuInSe2 NW surfaces showing the lotus effect. • Current–voltage plots revealed that the CuInSe2 NW arrays were p-type semiconductors; moreover, the core–shell structure improved the diode ideality factor from 3.91 to 2.63. - Abstract: Copper indium selenide (CuInSe 2 ) nanowire (NW) arrays were prepared at various electrolyte duty cycles by filling anodic alumina templates through the pulsed electrodeposition technique. X-ray diffraction and scanning electron microscopy (SEM) images showed that the nucleation mechanism of CuInSe 2 NW arrays was affected by the electrodeposition duty cycle. Moreover, SEM images showed that the diameter and length of the NWs were 80 nm and 2 μm, respectively. Furthermore, PEDOT/CuInSe 2 NW core–shell arrays were fabricated using surfactant-modified CuInSe 2 NW surfaces showing the lotus effect. Transmission electron microscopy images confirmed that a core–shell structure was achieved. Current–voltage plots revealed that the CuInSe 2 NW arrays were p-type semiconductors; moreover, the core–shell structure improved the diode ideality factor from 3.91 to 2.63.

  15. A Narrative Review of High-Quality Literature on the Effects of Resident Duty Hours Reforms.

    Science.gov (United States)

    Lin, Henry; Lin, Emery; Auditore, Stephanie; Fanning, Jon

    2016-01-01

    To summarize current high-quality studies evaluating the effect and efficacy of resident duty hours reforms (DHRs) on patient safety and resident education and well-being. The authors searched PubMed and Medline in August 2012 and again in May 2013 for literature (1987-2013) about the effects of DHRs. They assessed the quality of articles using the Medical Education Research Study Quality Instrument (MERSQI) scoring system. They considered randomized controlled trials (RCTs), partial RCTs, and all studies with a MERSQI score ≥ 14 to be "high-quality" methodology studies. A total of 72 high-quality studies met inclusion criteria. Most studies showed no change or slight improvement in mortality and complication rates after DHRs. Resident well-being was generally improved, but there was a perceived negative impact on education (knowledge acquisition, skills, and cognitive performance) following DHRs. Eleven high-quality studies assessed the impact of DHR interventions; all reported a neutral to positive impact. Seven high-quality studies assessed costs associated with DHRs and demonstrated an increase in hospital costs. The results of most studies that allow enough time for DHR interventions to take effect suggest a benefit to patient safety and resident well-being, but the effect on the quality of training remains unknown. Additional methodologically sound studies on the impact of DHRs are necessary. Priorities for future research include approaches to optimizing education and clinical proficiency and studies on the effect of intervention strategies on both education and patient safety. Such studies will provide additional information to help improve duty hours policies.

  16. High energy multi-cycle terahertz generation

    International Nuclear Information System (INIS)

    Ahr, Frederike Beate

    2017-10-01

    Development of compact electron accelerators and free-electron lasers requires novel acceleration schemes at shorter driving wavelengths. The Axsis project seeks to develop terahertz based electron acceleration as well as the high energy terahertz sources required. This thesis explores the methods and optical material required for the generation of highenergy multi-cycle terahertz pulses. Two experimental concepts to generate high energy terahertz radiation are presented. In addition the theoretical background and the optical properties of pertinent optical materials in the terahertz range are discussed. Investigations of the materials are performed with a terahertz time domain spectrometer and a Fourier transform infrared spectrometer. The nonlinear optical crystal lithium niobate as well as other crystals suitable for the terahertz generation and in addition polymers and other radiation attenuators are characterized in the range from 0.2 to 1 THz. The theory describing the generation of narrowband terahertz radiation is evaluated. The experimental setups to generate terahertz radiation and to characterize its properties are described. The specific crystals - periodically poled lithium niobate (PPLN) - used in the experiments to generate the multi-cycle terahertz radiation are examined to determine e.g. the poling period. The first experimental concept splits the ultra fast, broadband pump pulses into a pulse train in order to pump the PPLN at a higher fluence while increasing the damage limit. The measurements confirm that a pulse train of ultra short, broadband pump pulses increases not only the terahertz energy but also the energy conversion efficiency. The second experimental concept utilizes chirped and delayed infrared laser pulses. This pulse format makes it possible to pump the crystal with high energy pulses resulting in high energy terahertz radiation. The concept is optimized to reach energies up to 127 μJ exceeding the existing results of narrowband

  17. High energy multi-cycle terahertz generation

    Energy Technology Data Exchange (ETDEWEB)

    Ahr, Frederike Beate

    2017-10-15

    Development of compact electron accelerators and free-electron lasers requires novel acceleration schemes at shorter driving wavelengths. The Axsis project seeks to develop terahertz based electron acceleration as well as the high energy terahertz sources required. This thesis explores the methods and optical material required for the generation of highenergy multi-cycle terahertz pulses. Two experimental concepts to generate high energy terahertz radiation are presented. In addition the theoretical background and the optical properties of pertinent optical materials in the terahertz range are discussed. Investigations of the materials are performed with a terahertz time domain spectrometer and a Fourier transform infrared spectrometer. The nonlinear optical crystal lithium niobate as well as other crystals suitable for the terahertz generation and in addition polymers and other radiation attenuators are characterized in the range from 0.2 to 1 THz. The theory describing the generation of narrowband terahertz radiation is evaluated. The experimental setups to generate terahertz radiation and to characterize its properties are described. The specific crystals - periodically poled lithium niobate (PPLN) - used in the experiments to generate the multi-cycle terahertz radiation are examined to determine e.g. the poling period. The first experimental concept splits the ultra fast, broadband pump pulses into a pulse train in order to pump the PPLN at a higher fluence while increasing the damage limit. The measurements confirm that a pulse train of ultra short, broadband pump pulses increases not only the terahertz energy but also the energy conversion efficiency. The second experimental concept utilizes chirped and delayed infrared laser pulses. This pulse format makes it possible to pump the crystal with high energy pulses resulting in high energy terahertz radiation. The concept is optimized to reach energies up to 127 μJ exceeding the existing results of narrowband

  18. Coincidence set-up with a high duty-cycle, high energy electron accelerator

    International Nuclear Information System (INIS)

    Leconte, P.

    1981-01-01

    Important studies are now undertaken to develop continuous wave electron accelerators with energy ranging from 1 to 4 Gev. So very important effort must be now put on the development of the experimental set-up matching the performances expected from the electron beam. Major steps in the understanding of the nuclear systems will come from more and more exclusive experiments where well defined mechanisms will be selected

  19. Comparison of Cooling System Designs for an Exhaust Heat Recovery System Using an Organic Rankine Cycle on a Heavy Duty Truck

    Directory of Open Access Journals (Sweden)

    Nicolas Stanzel

    2016-11-01

    Full Text Available A complex simulation model of a heavy duty truck, including an Organic Rankine Cycle (ORC based waste heat recovery system and a vehicle cooling system, was applied to determine the system fuel economy potential in a typical drive cycle. Measures to increase the system performance were investigated and a comparison between two different cooling system designs was derived. The base design, which was realized on a Mercedes-Benz Actros vehicle revealed a fuel efficiency benefit of 2.6%, while a more complicated design would generate 3.1%. Furthermore, fully transient simulation results were performed and are compared to steady state simulation results. It is shown that steady state simulation can produce comparable results if averaged road data are used as boundary conditions.

  20. A novel respiratory motion compensation strategy combining gated beam delivery and mean target position concept - A compromise between small safety margins and long duty cycles

    International Nuclear Information System (INIS)

    Guckenberger, Matthias; Kavanagh, Anthony; Webb, Steve; Brada, Michael

    2011-01-01

    Purpose: To evaluate a novel respiratory motion compensation strategy combining gated beam delivery with the mean target position (MTP) concept for pulmonary stereotactic body radiotherapy (SBRT). Materials and methods: Four motion compensation strategies were compared for 10 targets with motion amplitudes between 6 mm and 31 mm: the internal target volume concept (plan ITV ); the MTP concept where safety margins were adapted based on 4D dose accumulation (plan MTP ); gated beam delivery without margins for motion compensation (plan gated ); a novel approach combining gating and the MTP concept (plan gated and MTP ). Results: For 5/10 targets with an average motion amplitude of 9 mm, the differences in the mean lung dose (MLD) between plan gated and plan MTP were gated and MTP . Despite significantly shorter duty cycles, plan gated reduced the MLD by gated and MTP . The MLD was increased by 18% in plan MTP compared to that of plan gated and MTP . Conclusions: For pulmonary targets with motion amplitudes >10-15 mm, the combination of gating and the MTP concept allowed small safety margins with simultaneous long duty cycles.

  1. Life-cycle implications of hydrogen fuel cell electric vehicle technology for medium- and heavy-duty trucks

    Science.gov (United States)

    Lee, Dong-Yeon; Elgowainy, Amgad; Kotz, Andrew; Vijayagopal, Ram; Marcinkoski, Jason

    2018-07-01

    This study provides a comprehensive and up-to-date life-cycle comparison of hydrogen fuel cell electric trucks (FCETs) and their conventional diesel counterparts in terms of energy use and air emissions, based on the ensemble of well-established methods, high-fidelity vehicle dynamic simulations, and real-world vehicle test data. For the centralized steam methane reforming (SMR) pathway, hydrogen FCETs reduce life-cycle or well-to-wheel (WTW) petroleum energy use by more than 98% compared to their diesel counterparts. The reduction in WTW air emissions for gaseous hydrogen (G.H2) FCETs ranges from 20 to 45% for greenhouse gases, 37-65% for VOC, 49-77% for CO, 62-83% for NOx, 19-43% for PM10, and 27-44% for PM2.5, depending on vehicle weight classes and truck types. With the current U.S. average electricity generation mix, FCETs tend to create more WTW SOx emissions than their diesel counterparts, mainly because of the upstream emissions related to electricity use for hydrogen compression/liquefaction. Compared to G.H2, liquid hydrogen (L.H2) FCETs generally provide smaller WTW emissions reductions. For both G.H2 and L.H2 pathways for FCETs, because of electricity consumption for compression and liquefaction, spatio-temporal variations of electricity generation can affect the WTW results. FCETs retain the WTW emission reduction benefits, even when considering aggressive diesel engine efficiency improvement.

  2. 49 CFR Appendix C to Part 541 - Criteria for Selecting Light Duty Truck Lines Likely To Have High Theft Rates

    Science.gov (United States)

    2010-10-01

    ... Likely To Have High Theft Rates C Appendix C to Part 541 Transportation Other Regulations Relating to... MOTOR VEHICLE THEFT PREVENTION STANDARD Pt. 541, App. C Appendix C to Part 541—Criteria for Selecting Light Duty Truck Lines Likely To Have High Theft Rates Scope These criteria specify the factors the...

  3. High cycle fatigue properties of inconel 690

    International Nuclear Information System (INIS)

    Lee, Young Ho; Lee, Byong Whi; Kim, In Sup; Park, Chi Yong

    1997-01-01

    Inconel 690 is presently used as sleeve material and a replacement alloy in degraded steam generators, as well as the material for new steam generators. But Inconel 690 has low thermal conductivity which are 3-8% less than that of Inconel 600 at operating temperature. For the same power output, conduction area must be increased. As a result, more fluid induced vibration can cause a fatigue damage of Inconel 690. High cycle fatigue ruptures occurred in the U-bend regions of North Anna Unit 1 and Mihama Unit 2 steam generators. At this study, the effect of temperature on fatigue crack growth rate in Inconel 690 steam generator tube was investigated at various temperature in air environment. With increasing temperature, fatigue crack growth rate increased and grain size effect decreased. Chromium carbides which have large size and semi-continuous distribution in the grain boundaries decreased fatigue crack growth rate

  4. A comprehensive design methodology of organic Rankine cycles for the waste heat recovery of automotive heavy-duty diesel engines

    International Nuclear Information System (INIS)

    Amicabile, Simone; Lee, Jeong-Ik; Kum, Dongsuk

    2015-01-01

    One of the most promising approaches to recover the waste heat from internal combustion engines is the Organic Rankine Cycle owing to its efficiency and reliability. The design optimization of ORC, however, is nontrivial because there exist many design variables and practical considerations. The present paper proposes a comprehensive design methodology to optimize the Organic Rankine Cycles (ORC) considering a wide range of design variables as well as practical aspects such as component limitations and costs. The design process is comprised of three steps: heat source selection, candidate fluid selection, and thermodynamic cycle optimization. In order to select the best waste heat source, the available energy and other practical considerations of various heat sources have been compared. Among others, the Exhaust Gas Recirculation (EGR) cooler is found to be the best heat source, and thus used for the rest of this study. Based on a systematic working fluid analysis, Ethanol, Pentane, and R245fa are selected as three candidate fluids. For the comprehensive ORC optimization, four types of cycle layouts are considered; 1) subcritical cycle without a recuperator, 2) subcritical cycle with a recuperator, 3) supercritical without a recuperator, and 4) supercritical cycle with a recuperator. Four cycle layouts coupled with three candidate fluids give a total of twelve cycle analyses. Results show that the best performance is provided by the regenerative subcritical cycle with Ethanol, while the solution with minimum capital cost is the subcritical cycles with Ethanol but without a recuperator. - Highlights: • Selection of the best waste heat source of a diesel engine for a heat recovery system. • Screening process to identify the most suitable working fluids for the system. • Comprehensive ORC optimization is introduced for four types of cycle layouts. • Pay Back Time investigation to present the economic analysis of the cycles

  5. Appliance of high EGR rates with a short and long route EGR system on a heavy duty diesel engine

    NARCIS (Netherlands)

    Aken, van M.; Willems, F.P.T.; Jong, de D.J.

    2007-01-01

    The goal of this work was to investigate the possibilities of applying high EGR rates with low NOx and PM emission levels on a two-stage turbocharged 12 liter heavy duty diesel engine. The EGR is applied by using a long and short route EGR system. For the ESC operating points A25 and C100 EGR is

  6. Specific features of high-cycle and ultra-high-cycle fatigue

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík

    2002-01-01

    Roč. 25, - (2002), s. 747-753 ISSN 8756-758X R&D Projects: GA AV ČR KSK1010104; GA AV ČR IAA2041002 Institutional research plan: CEZ:AV0Z2041904 Keywords : ultra high cycle fatigue * fatigue mechanisms * cyclic plastic deformation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.701, year: 2002

  7. Trade-Offs between Energy Saving and Reliability in Low Duty Cycle Wireless Sensor Networks Using a Packet Splitting Forwarding Technique

    Directory of Open Access Journals (Sweden)

    Leonardi Alessandro

    2010-01-01

    Full Text Available One of the challenging topics and design constraints in Wireless Sensor Networks (WSNs is the reduction of energy consumption because, in most application scenarios, replacement of power resources in sensor devices might be unfeasible. In order to minimize the power consumption, some nodes can be put to sleep during idle times and wake up only when needed. Although it seems the best way to limit the consumption of energy, other performance parameters such as network reliability have to be considered. In a recent paper, we introduced a new forwarding algorithm for WSNs based on a simple splitting procedure able to increase the network lifetime. The forwarding technique is based on the Chinese Remainder Theorem and exhibits very good results in terms of energy efficiency and complexity. In this paper, we intend to investigate a trade-off between energy efficiency and reliability of the proposed forwarding scheme when duty-cycling techniques are considered too.

  8. High cycle fatigue of austenitic stainless steels

    International Nuclear Information System (INIS)

    Gauthier, J.P.; Lehmann, D.; Picker

    1990-01-01

    This study concerns the evaluation of material data to be used in LMFBR design codes. High cycle fatigue properties of three austenitic stainless steels are evaluated: type AISI 316 (UKAEA tests), type AISI 316L (CEA tests) and type AISI 304 (Interatom tests). The data on these steels comprised some 550 data points from 14 casts. This data set covered a wide range of testing parameters: temperature from 20-625 0 C, frequency from 1-20 000 Hz, constant amplitude and random fatigue loading, with and without mean stress, etc. However, the testing conditions chosen by the three partners differed considerably because they had been fixed independently and not harmonized prior to the tests. This created considerable difficulties for the evaluations. Experimental procedures and statistical treatments used for the three subsets of data are described and discussed. Results are presented in tables and graphs. Although it is often difficult to single out the influence of each parameter due to the different testing conditions, several interesting conclusions can be drawn: The HCF properties of the three steels are consistent with the 0.2% proof stress, the fatigue limit being larger than the latter at temperatures above 550 0 C. The type 304 steel has lower tensile properties than the two other steels and hence also lower HCF properties. Parameters which clearly have a significant effect of HCF behaviour are mean stress or R-ratio (less in the non-endurance region than in the endurance region), temperature, cast or product. Other parameters have probably a weak or no effect but it is difficult to conclude due to insufficient data: environment, specimen orientation, frequency, specimen geometry

  9. Part-load performance of a high temperature Kalina cycle

    DEFF Research Database (Denmark)

    Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl

    2015-01-01

    The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine...

  10. Emissions of toxic pollutants from compressed natural gas and low sulfur diesel-fueled heavy-duty transit buses tested over multiple driving cycles.

    Science.gov (United States)

    Kado, Norman Y; Okamoto, Robert A; Kuzmicky, Paul A; Kobayashi, Reiko; Ayala, Alberto; Gebel, Michael E; Rieger, Paul L; Maddox, Christine; Zafonte, Leo

    2005-10-01

    The number of heavy-duty vehicles using alternative fuels such as compressed natural gas (CNG) and new low-sulfur diesel fuel formulations and equipped with after-treatment devices are projected to increase. However, few peer-reviewed studies have characterized the emissions of particulate matter (PM) and other toxic compounds from these vehicles. In this study, chemical and biological analyses were used to characterize the identifiable toxic air pollutants emitted from both CNG and low-sulfur-diesel-fueled heavy-duty transit buses tested on a chassis dynamometer over three transient driving cycles and a steady-state cruise condition. The CNG bus had no after-treatment, and the diesel bus was tested first equipped with an oxidation catalyst (OC) and then with a catalyzed diesel particulate filter (DPF). Emissions were analyzed for PM, volatile organic compounds (VOCs; determined on-site), polycyclic aromatic hydrocarbons (PAHs), and mutagenic activity. The 2000 model year CNG-fueled vehicle had the highest emissions of 1,3-butadiene, benzene, and carbonyls (e.g., formaldehyde) of the three vehicle configurations tested in this study. The 1998 model year diesel bus equipped with an OC and fueled with low-sulfur diesel had the highest emission rates of PM and PAHs. The highest specific mutagenic activities (revertants/microg PM, or potency) and the highest mutagen emission rates (revertants/mi) were from the CNG bus in strain TA98 tested over the New York Bus (NYB) driving cycle. The 1998 model year diesel bus with DPF had the lowest VOCs, PAH, and mutagenic activity emission. In general, the NYB driving cycle had the highest emission rates (g/mi), and the Urban Dynamometer Driving Schedule (UDDS) had the lowest emission rates for all toxics tested over the three transient test cycles investigated. Also, transient emissions were, in general, higher than steady-state emissions. The emissions of toxic compounds from an in-use CNG transit bus (without an oxidation

  11. Part-load performance of a high temperature Kalina cycle

    International Nuclear Information System (INIS)

    Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl; Haglind, Fredrik

    2015-01-01

    Highlights: • Detailed algorithm to solve high temperature Kalina cycle in part load. • A central receiver concentrating solar power plant with direct vapour generation considered as case study. • Part-load performance curves and fitted equations presented. - Abstract: The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine bottoming cycle, and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated by changing the solar heat input to the receiver. Compared with the steam Rankine cycle, the Kalina cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the cycle. The results include the part-load curves for various turbine inlet ammonia mass fractions and the fitted equations for these curves.

  12. Electrifying Australian transport: Hybrid life cycle analysis of a transition to electric light-duty vehicles and renewable electricity

    International Nuclear Information System (INIS)

    Wolfram, Paul; Wiedmann, Thomas

    2017-01-01

    Highlights: •This research assesses life-cycle carbon impacts of different powertrains. •We illustrate a transition to low-carbon vehicles in a hybrid IO-LCA model. •Different electricity and transport scenarios are integrated in the model. •With Australia’s current grid-mix, electric vehicles offer no mitigation potential. •Using renewable energy, electric vehicle carbon footprints can be cut by 66%. -- Abstract: Recent life cycle assessments confirmed the greenhouse gas emission reduction potential of renewable electricity and electric vehicle technologies. However, each technology is usually assessed separately and not within a consistent macro-economic, multi-sectoral framework. Here we present a multi-regional input-output based hybrid approach with integrated scenarios to facilitate the carbon footprint assessment of all direct and indirect effects of a transition to low-emission transportation and electricity generation technologies in Australia. The work takes into account on-road energy consumption values that are more realistic than official drive-cycle energy consumption figures used in previous work. Accounting for these factors as well as for Australia’s grid electricity, which heavily relies on coal power, electric vehicles are found to have a higher carbon footprint than conventional vehicles, whereas hybrid electric vehicles have the lowest. This means that – from a carbon footprint perspective – powertrain electrification is beneficial only to a certain degree at the current stage. This situation can be changed by increasing shares of renewable electricity in the grid. In our best-case scenario, where renewable energy accounts for 96% of the electricity mix in 2050, electric vehicle carbon footprints can be cut by 66% by 2050 relative to 2009. In the business-as-usual scenario (36% renewable electricity share by 2050), electric vehicles can reach a 56% reduction if fossil fuel power plants significantly increase their efficiencies

  13. High-conversion HTRs and their fuel cycle

    International Nuclear Information System (INIS)

    Gutmann, H.; Hansen, U.; Larsen, H.; Price, M.S.T.

    1976-01-01

    The high-temperature reactors using graphite as structural core material and helium as coolant represent thermal reactor designs with a very high degree of neutron economy which, when using the thorium fuel cycle, offer, at least theoretically, the possibility of thermal breeding. Though this was already known from previous studies, the economic climate at that time was such that the achievement of high conversion ratios conflicted with the incentive for low fuel cycle costs. Consequently, thorium cycle conversion ratios of around 0.6 were found optimum, and the core and fuel element layout followed from the economic ground rules. The recent change in attitude, brought about partly by the slow process of realization of the limits to the earth's accessible high-grade uranium ore resources and more dramatically by the oil crisis, makes it necessary to concentrate attention again on the high conversion fuel cycles. This report discusses the principles of the core design and the fuel cycle layout for High Conversion HTRs (HCHTRs). Though most of the principles apply equally to HTRs of the pebble-bed and the prismatic fuel element design types, the paper concentrates on the latter. Design and fuel cycle strategies for the full utilization of the high conversion potential are compared with others that aim at easier reprocessing and the ''environmental'' fuel cycle. The paper concludes by discussing operating and fuel cycle characteristics and economics of HCHTRs, and how the latter impinge on the allowable price for uranium ore and the available uranium resources. (author)

  14. Development of Advanced High Strength Cast Alloys for Heavy Duty Engines

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, James [Caterpillar Inc., Mossville, IL (United States)

    2017-06-13

    Gray iron has been the primary alloy for heavy duty diesel engine core castings for decades. During recent decades the limitations of gray iron have been reached in some applications, leading to the use of compacted graphite iron in engine blocks and heads. Caterpillar has had compacted graphite designs in continuous production since the late 1980’s. Due to the drive for higher power density, decreased emissions and increased fuel economy, cylinder pressures and temperatures continue to increase. Currently no viable replacement for today’s compacted graphite irons exist at an acceptable cost level. This project explored methods to develop the next generation of heavy duty diesel engine materials as well as demonstrated some results on new alloy designs although cost targets will likely not be met.

  15. Development of Heavy-Duty and High-Precision Hydraulic Manipulator for Inspection, Maintenance and Decommission of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Uk; Seo, Yong-chil; Jung, Kyung Min; Kim, Chang-hoi; Choi, Byung-seon; Moon, Jei-kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Robotic manipulators have been used for inspection, maintenance and decommission of nuclear power plants because nuclear power plants have high radiation and human workers cannot easily access the plants. And also, to inspecting, maintaining and decommissioning nuclear power plants require various manipulators. Only one manipulator cannot response to many required tasks. The existing manipulators that was used at nuclear power plants can only operate only focused specific task and cannot be used at several tasks. The actuators used at manipulators are varied and many companies sell actuators depending on power, torque and speed. However, the commercial product is not standardized. Therefore, the development of manipulator is time consuming and expensive. The essential item of a manipulator is an actuator module. If actuator module is standardized, it’s easier to develop a manipulator and also maintain a manipulator. Recently, manipulator having high-radiation, high-duty and high-precision is necessary to inspection, maintain and decommissioning of nuclear power plants. Hydraulic actuator has been used to development high-duty manipulator. But control performance of a hydraulic actuator is not better than that of an electric actuator so that hydraulic manipulator cannot easily satisfy the required precision. In this paper, we developed high-duty and high-precision actuator modules and hydraulic manipulator using the developed actuator modules. The developed hydraulic manipulator have a payload of 250kg and a precision of ±1mm. Four modularized hydraulic actuator modules were developed for inspection, maintenance and decommission. Using the developed actuator modules, the manipulator for decommissioning is easily developed. And also, various manipulators having different kinematic structure for specific tasks will be easily developed by using hydraulic modules.

  16. Development of Heavy-Duty and High-Precision Hydraulic Manipulator for Inspection, Maintenance and Decommission of Nuclear Power Plants

    International Nuclear Information System (INIS)

    Lee, Sung Uk; Seo, Yong-chil; Jung, Kyung Min; Kim, Chang-hoi; Choi, Byung-seon; Moon, Jei-kwon

    2016-01-01

    Robotic manipulators have been used for inspection, maintenance and decommission of nuclear power plants because nuclear power plants have high radiation and human workers cannot easily access the plants. And also, to inspecting, maintaining and decommissioning nuclear power plants require various manipulators. Only one manipulator cannot response to many required tasks. The existing manipulators that was used at nuclear power plants can only operate only focused specific task and cannot be used at several tasks. The actuators used at manipulators are varied and many companies sell actuators depending on power, torque and speed. However, the commercial product is not standardized. Therefore, the development of manipulator is time consuming and expensive. The essential item of a manipulator is an actuator module. If actuator module is standardized, it’s easier to develop a manipulator and also maintain a manipulator. Recently, manipulator having high-radiation, high-duty and high-precision is necessary to inspection, maintain and decommissioning of nuclear power plants. Hydraulic actuator has been used to development high-duty manipulator. But control performance of a hydraulic actuator is not better than that of an electric actuator so that hydraulic manipulator cannot easily satisfy the required precision. In this paper, we developed high-duty and high-precision actuator modules and hydraulic manipulator using the developed actuator modules. The developed hydraulic manipulator have a payload of 250kg and a precision of ±1mm. Four modularized hydraulic actuator modules were developed for inspection, maintenance and decommission. Using the developed actuator modules, the manipulator for decommissioning is easily developed. And also, various manipulators having different kinematic structure for specific tasks will be easily developed by using hydraulic modules

  17. Survey of physics research with a high duty cycle electron accelerator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Earle, E.D.; Knowles, J.W.; Lone, M.A.

    1981-02-01

    The opportunities for nuclear physics research afforded by a CW electron linac with nominal energy 100 MeV and beam current >= 100 μA equipped with a bremsstrahlung monochromator and reaction product coincidence facilities are outlined. It is proposed that a program toward realization of an accelerator meeting these requirements and with provision for eventual extension to higher energies be undertaken at the Chalk River Nuclear Laboratories. (author)

  18. Evaluation of the dependence of CEST-EPI measurement on repetition time, RF irradiation duty cycle and imaging flip angle for enhanced pH sensitivity

    International Nuclear Information System (INIS)

    Sun, Phillip Zhe; Lu Jie; Wu Yin; Xiao Gang; Wu Renhua

    2013-01-01

    Chemical exchange saturation transfer (CEST) is a magnetic resonance imaging (MRI) contrast mechanism that can detect dilute CEST agents and microenvironmental properties, with a host of promising applications. Experimental measurement of the CEST effect is complex, and depends on not only CEST agent concentration and exchange rate, but also experimental parameters such as RF irradiation amplitude and scheme. Although echo planar imaging (EPI) has been increasingly used for CEST MRI, the relationship between CEST effect and repetition time (TR), RF irradiation duty cycle (DC) and EPI flip angle (α) has not been fully evaluated and optimized to enhance CEST MRI sensitivity. In addition, our study evaluated gradient echo CEST-EPI by quantifying the CEST effect and its signal-to-noise ratio per unit time (SNR put ) as functions of TR, DC and α. We found that CEST effect increased with TR and DC but decreased with α. Importantly, we found that SNR put peaked at intermediate TRs of about twice the T 1 and α, at approximately 75°, and increased with RF DC. The simulation results were validated using a dual-pH creatine-gel CEST phantom. In summary, our study provides a useful framework for optimizing CEST MRI experiments. (note)

  19. Similarity Theory Based Radial Turbine Performance and Loss Mechanism Comparison between R245fa and Air for Heavy-Duty Diesel Engine Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2017-01-01

    Full Text Available Organic Rankine Cycles using radial turbines as expanders are considered as one of the most efficient technologies to convert heavy-duty diesel engine waste heat into useful work. Turbine similarity design based on the existing air turbine profiles is time saving. Due to totally different thermodynamic properties between organic fluids and air, its influence on turbine performance and loss mechanisms need to be analyzed. This paper numerically simulated a radial turbine under similar conditions between R245fa and air, and compared the differences of the turbine performance and loss mechanisms. Larger specific heat ratio of air leads to air turbine operating at higher pressure ratios. As R245fa gas constant is only about one-fifth of air gas constant, reduced rotating speeds of R245fa turbine are only 0.4-fold of those of air turbine, and reduced mass flow rates are about twice of those of air turbine. When using R245fa as working fluid, the nozzle shock wave losses decrease but rotor suction surface separation vortex losses increase, and eventually leads that isentropic efficiencies of R245fa turbine in the commonly used velocity ratio range from 0.5 to 0.9 are 3%–4% lower than those of air turbine.

  20. High-intensity cycle interval training improves cycling and running performance in triathletes.

    Science.gov (United States)

    Etxebarria, Naroa; Anson, Judith M; Pyne, David B; Ferguson, Richard A

    2014-01-01

    Effective cycle training for triathlon is a challenge for coaches. We compared the effects of two variants of cycle high-intensity interval training (HIT) on triathlon-specific cycling and running. Fourteen moderately-trained male triathletes ([Formula: see text]O2peak 58.7 ± 8.1 mL kg(-1) min(-1); mean ± SD) completed on separate occasions a maximal incremental test ([Formula: see text]O2peak and maximal aerobic power), 16 × 20 s cycle sprints and a 1-h triathlon-specific cycle followed immediately by a 5 km run time trial. Participants were then pair-matched and assigned randomly to either a long high-intensity interval training (LONG) (6-8 × 5 min efforts) or short high-intensity interval training (SHORT) (9-11 × 10, 20 and 40 s efforts) HIT cycle training intervention. Six training sessions were completed over 3 weeks before participants repeated the baseline testing. Both groups had an ∼7% increase in [Formula: see text]O2peak (SHORT 7.3%, ±4.6%; mean, ±90% confidence limits; LONG 7.5%, ±1.7%). There was a moderate improvement in mean power for both the SHORT (10.3%, ±4.4%) and LONG (10.7%, ±6.8%) groups during the last eight 20-s sprints. There was a small to moderate decrease in heart rate, blood lactate and perceived exertion in both groups during the 1-h triathlon-specific cycling but only the LONG group had a substantial decrease in the subsequent 5-km run time (64, ±59 s). Moderately-trained triathletes should use both short and long high-intensity intervals to improve cycling physiology and performance. Longer 5-min intervals on the bike are more likely to benefit 5 km running performance.

  1. Utilisation of reactor heat in methanol synthesis to reduce compressor duty : application of power cycle principles and simulation tools

    NARCIS (Netherlands)

    Greeff, I.L.; Visser, J.A.; Ptasinski, K.J.; Janssen, F.J.J.G.

    2002-01-01

    The chemical conversion in a methanol reactor is restricted by equilibrium, therefore the synthesis loop is operated at high pressure and unconverted gas is recycled. Such a synthesis loop consumes large amounts of compression work. In this paper a new flow sheet for methanol synthesis is presented.

  2. Ignition assist systems for direct-injected, diesel cycle, medium-duty alternative fuel engines: Final report phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Chan, A.K.

    2000-02-23

    This report is a summary of the results of Phase 1 of this contract. The objective was to evaluate the potential of assist technologies for direct-injected alternative fuel engines vs. glow plug ignition assist. The goal was to demonstrate the feasibility of an ignition system life of 10,000 hours and a system cost of less than 50% of the glow plug system, while meeting or exceeding the engine thermal efficiency obtained with the glow plug system. There were three tasks in Phase 1. Under Task 1, a comprehensive review of feasible ignition options for DING engines was completed. The most promising options are: (1) AC and the ''SmartFire'' spark, which are both long-duration, low-power (LDLP) spark systems; (2) the short-duration, high-power (SDHP) spark system; (3) the micropilot injection ignition; and (4) the stratified charge plasma ignition. Efforts concentrated on investigating the AC spark, SmartFire spark, and short-duration/high-power spark systems. Using proprietary pricing information, the authors predicted that the commercial costs for the AC spark, the short-duration/high-power spark and SmartFire spark systems will be comparable (if not less) to the glow plug system. Task 2 involved designing and performing bench tests to determine the criteria for the ignition system and the prototype spark plug for Task 3. The two most important design criteria are the high voltage output requirement of the ignition system and the minimum electrical insulation requirement for the spark plug. Under Task 3, all the necessary hardware for the one-cylinder engine test was designed. The hardware includes modified 3126 cylinder heads, specially designed prototype spark plugs, ignition system electronics, and parts for the system installation. Two 3126 cylinder heads and the SmartFire ignition system were procured, and testing will begin in Phase 2 of this subcontract.

  3. Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A.I.; Som, S.; Aggarwal, Suresh K. [University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL (United States); Kastengren, A.L.; El-Hannouny, E.M.; Longman, D.E.; Powell, C.F. [Argonne National Laboratory, Energy Systems Division, Argonne, IL (United States)

    2009-07-15

    A quantitative and time-resolved X-ray radiography technique has been used for detailed measurements of high-pressure fuel sprays in the near-nozzle region of a diesel engine injector. The technique provides high spatial and temporal resolution, especially in the relatively dense core region. A single spray plume from a hydraulically actuated electronically controlled unit injector model 315B injector with a 6-hole nozzle was isolated and studied at engine-like densities for two different injection pressures. Optical spray imaging was also employed to evaluate the effectiveness of the shield used to isolate a single spray plume. The steady state fuel distributions for both injection pressures are similar and show a dense spray region along the axis of the spray, with the on-axis spray density decreasing as the spray progresses downstream. The higher injection pressure case exhibits a larger cone angle and spray broadening at the exit of the nozzle. For some time periods, the near-nozzle penetration speed is lower for the high injection pressure case than the low injection pressure case, which is unexpected, but can be attributed to the needle and flow dynamics inside the injector causing slower pressure build-up for the former case. Rate of injection testing was performed to further understand near-nozzle behavior. Mass distribution data were obtained and used to find mass-averaged velocity of the spray. Comparisons of the radiography data with that from a common rail single-hole light duty injectors under similar injection conditions show several significant differences. The current data show a larger cone angle and lower penetration speed than that from the light-duty injector. Moreover, these data display a Gaussian mass distribution across the spray near the injector, whereas in previous light-duty injector measurements, the mass distribution had steeper sides and a flatter peak. Measurements are also used to examine the spray models in the STAR-CD software

  4. Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector

    Science.gov (United States)

    Ramírez, A. I.; Som, S.; Aggarwal, Suresh K.; Kastengren, A. L.; El-Hannouny, E. M.; Longman, D. E.; Powell, C. F.

    2009-07-01

    A quantitative and time-resolved X-ray radiography technique has been used for detailed measurements of high-pressure fuel sprays in the near-nozzle region of a diesel engine injector. The technique provides high spatial and temporal resolution, especially in the relatively dense core region. A single spray plume from a hydraulically actuated electronically controlled unit injector model 315B injector with a 6-hole nozzle was isolated and studied at engine-like densities for two different injection pressures. Optical spray imaging was also employed to evaluate the effectiveness of the shield used to isolate a single spray plume. The steady state fuel distributions for both injection pressures are similar and show a dense spray region along the axis of the spray, with the on-axis spray density decreasing as the spray progresses downstream. The higher injection pressure case exhibits a larger cone angle and spray broadening at the exit of the nozzle. For some time periods, the near-nozzle penetration speed is lower for the high injection pressure case than the low injection pressure case, which is unexpected, but can be attributed to the needle and flow dynamics inside the injector causing slower pressure build-up for the former case. Rate of injection testing was performed to further understand near-nozzle behavior. Mass distribution data were obtained and used to find mass-averaged velocity of the spray. Comparisons of the radiography data with that from a common rail single-hole light duty injectors under similar injection conditions show several significant differences. The current data show a larger cone angle and lower penetration speed than that from the light-duty injector. Moreover, these data display a Gaussian mass distribution across the spray near the injector, whereas in previous light-duty injector measurements, the mass distribution had steeper sides and a flatter peak. Measurements are also used to examine the spray models in the STAR-CD software.

  5. Fuel and fuel cycles with high burnup for WWER reactors

    International Nuclear Information System (INIS)

    Chernushev, V.; Sokolov, F.

    2002-01-01

    The paper discusses the status and trends in development of nuclear fuel and fuel cycles for WWER reactors. Parameters and main stages of implementation of new fuel cycles will be presented. At present, these new fuel cycles are offered to NPPs. Development of new fuel and fuel cycles based on the following principles: profiling fuel enrichment in a cross section of fuel assemblies; increase of average fuel enrichment in fuel assemblies; use of refuelling schemes with lower neutron leakage ('in-in-out'); use of integrated fuel gadolinium-based burnable absorber (for a five-year fuel cycle); increase of fuel burnup in fuel assemblies; improving the neutron balance by using structural materials with low neutron absorption; use of zirconium alloy claddings which are highly resistant to irradiation and corrosion. The paper also presents the results of fuel operation. (author)

  6. Effect of high pressure hydrogen on low-cycle fatigue

    International Nuclear Information System (INIS)

    Rie, K.T.; Kohler, W.

    1979-01-01

    It has been shown that the fatigue life can be influenced in low-cycle range by high pressure hydrogen while the effect of high pressure hydrogen on high-cycle fatigue will not be as significant. The paper reports the details and the results of the investigations of the effect of high pressure hydrogen on the low-cycle endurance of commercially pure titanium. The results of this study indicate that: 1. The degradation of the fatigue life in low-cycle region for commercially pure titanium under high pressure hydrogen can be described by Nsub(cr)sup(α x Δepsilon)sub(pl)sup(=c) 2. The fatigue life decreases with decreasing strain rate. 3. The fatigue life decreases with increasing hydrogen pressure. It was found that the semilogarithmic plot of the fatigue life versus the hydrogen pressure gives a linear relationship. The Sievert's law does not hold in low-cycle fatigue region. 4. HAC in titanium in low-cycle fatigue region is the result of the disolution of hydrogen at the crack tip and of the strain-induced hybride formation. (orig.) 891 RW/orig. 892 RKD [de

  7. Phase synchronization of baroclinic waves in a differentially heated rotating annulus experiment subject to periodic forcing with a variable duty cycle.

    Science.gov (United States)

    Read, P L; Morice-Atkinson, X; Allen, E J; Castrejón-Pita, A A

    2017-12-01

    A series of laboratory experiments in a thermally driven, rotating fluid annulus are presented that investigate the onset and characteristics of phase synchronization and frequency entrainment between the intrinsic, chaotic, oscillatory amplitude modulation of travelling baroclinic waves and a periodic modulation of the (axisymmetric) thermal boundary conditions, subject to time-dependent coupling. The time-dependence is in the form of a prescribed duty cycle in which the periodic forcing of the boundary conditions is applied for only a fraction δ of each oscillation. For the rest of the oscillation, the boundary conditions are held fixed. Two profiles of forcing were investigated that capture different parts of the sinusoidal variation and δ was varied over the range 0.1≤δ≤1. Reducing δ was found to act in a similar way to a reduction in a constant coupling coefficient in reducing the width of the interval in forcing frequency or period over which complete synchronization was observed (the "Arnol'd tongue") with respect to the detuning, although for the strongest pulse-like forcing profile some degree of synchronization was discernible even at δ=0.1. Complete phase synchronization was obtained within the Arnol'd tongue itself, although the strength of the amplitude modulation of the baroclinic wave was not significantly affected. These experiments demonstrate a possible mechanism for intraseasonal and/or interannual "teleconnections" within the climate system of the Earth and other planets that does not rely on Rossby wave propagation across the planet along great circles.

  8. Idle emissions from heavy-duty diesel and natural gas vehicles at high altitude.

    Science.gov (United States)

    McCormick, R L; Graboski, M S; Alleman, T L; Yanowitz, J

    2000-11-01

    Idle emissions of total hydrocarbon (THC), CO, NOx, and particulate matter (PM) were measured from 24 heavy-duty diesel-fueled (12 trucks and 12 buses) and 4 heavy-duty compressed natural gas (CNG)-fueled vehicles. The volatile organic fraction (VOF) of PM and aldehyde emissions were also measured for many of the diesel vehicles. Experiments were conducted at 1609 m above sea level using a full exhaust flow dilution tunnel method identical to that used for heavy-duty engine Federal Test Procedure (FTP) testing. Diesel trucks averaged 0.170 g/min THC, 1.183 g/min CO, 1.416 g/min NOx, and 0.030 g/min PM. Diesel buses averaged 0.137 g/min THC, 1.326 g/min CO, 2.015 g/min NOx, and 0.048 g/min PM. Results are compared to idle emission factors from the MOBILE5 and PART5 inventory models. The models significantly (45-75%) overestimate emissions of THC and CO in comparison with results measured from the fleet of vehicles examined in this study. Measured NOx emissions were significantly higher (30-100%) than model predictions. For the pre-1999 (pre-consent decree) truck engines examined in this study, idle NOx emissions increased with model year with a linear fit (r2 = 0.6). PART5 nationwide fleet average emissions are within 1 order of magnitude of emissions for the group of vehicles tested in this study. Aldehyde emissions for bus idling averaged 6 mg/min. The VOF averaged 19% of total PM for buses and 49% for trucks. CNG vehicle idle emissions averaged 1.435 g/min for THC, 1.119 g/min for CO, 0.267 g/min for NOx, and 0.003 g/min for PM. The g/min PM emissions are only a small fraction of g/min PM emissions during vehicle driving. However, idle emissions of NOx, CO, and THC are significant in comparison with driving emissions.

  9. The high temperature reactor and its fuel cycle options

    International Nuclear Information System (INIS)

    1979-07-01

    The status of the HTR system in the Federal Republic of Germany as well as the consecutive steps and the probable cost of further development are presented. The considerations are based on a recycling Th/highly enriched uranium (HEU) fuel cycle which has been chosen as the main line of the German HTR R and D efforts. Alternative fuel cycles such as medium-enriched uranium (MEU) and low-enriched uranium (LEU) are discussed as well

  10. High performance integrated solar combined cycles with minimum modifications to the combined cycle power plant design

    International Nuclear Information System (INIS)

    Manente, Giovanni

    2016-01-01

    Highlights: • Off-design model of a 390 MW_e three pressure combined cycle developed and validated. • The off-design model is used to evaluate different hybridization schemes with solar. • Power boosting and fuel saving with different design modifications are considered. • Maximum solar share of total electricity is only 1% with the existing equipment. • The maximum incremental solar radiation-to-electrical efficiency approaches 29%. - Abstract: The integration of solar energy into natural gas combined cycles has been successfully demonstrated in several integrated solar combined cycles since the beginning of this decade in many countries. There are many motivations that drive investments on integrated solar combined cycles which are primarily the repowering of existing power plants, the compliance with more severe environmental laws on emissions and the mitigation of risks associated with large solar projects. Integrated solar combined cycles are usually developed as brownfield facilities by retrofitting existing natural gas combined cycles and keeping the existing equipment to minimize costs. In this work a detailed off-design model of a 390 MW_e three pressure level natural gas combined cycle is built to evaluate different integration schemes of solar energy which either keep the equipment of the combined cycle unchanged or include new equipment (steam turbine, heat recovery steam generator). Both power boosting and fuel saving operation strategies are analyzed in the search for the highest annual efficiency and solar share. Results show that the maximum incremental power output from solar at design solar irradiance is limited to 19 MW_e without modifications to the existing equipment. Higher values are attainable only including a larger steam turbine. High solar radiation-to-electrical efficiencies in the range 24–29% can be achieved in the integrated solar combined cycle depending on solar share and extension of tube banks in the heat recovery

  11. Selection of appropriate working fluids for Rankine cycles used for recovery of heat from exhaust gases of ICE in heavy-duty series hybrid electric vehicles

    International Nuclear Information System (INIS)

    Jung, Daebong; Park, Sungjin; Min, Kyoungdoug

    2015-01-01

    Recently, the waste heat recovery system is studied for application in vehicles to improve fuel economy. Especially, Rankine cycle is representative and attractive technology as waste heat recovery system. In order to maximize efficiency of Rankine cycle in the vehicle application, selection of optimal working fluid is important. Thus, in this study, thermodynamic analysis with consideration of practical operating condition was conducted to find out optimal working fluids. Thermodynamic efficiency, recovery efficiency, and overall cycle efficiency were adopted to estimate Rankine cycle performance. In order to reflect practical operating condition on the analysis, limitations due to working fluid physical properties and components specifications are taken into account. 5 working fluids including dry and wet fluid were used to estimate efficiency. Consequently, R245fa which shows high efficiency and environment-friendly is suggested as optimal working fluid in vehicle application. - Highlights: • 5 different working fluids were analyzed in respect of hybrid electric vehicle waste heat recovery system. • Real world operational conditions and limits are applied. • Optimal heating temperature of each working fluid show different trend. • R245fa is preferable among other fluids due to its high efficiency and impact on environment

  12. Low cycle fatigue: high cycle fatigue damage accumulation in a 304L austenitic stainless steel

    International Nuclear Information System (INIS)

    Lehericy, Y.

    2007-05-01

    The aim of this study was to evaluate the consequences of a Low Cycle Fatigue pre-damage on the subsequent fatigue limit of a 304L stainless steel. The effects of hardening and severe roughness (grinding) have also been investigated. In a first set of tests, the evolution of the surface damage induced by the different LCF pre-cycling was characterized. This has permitted to identify mechanisms and kinetics of damage in the plastic domain for different surface conditions. Then, pre-damaged samples were tested in the High Cycle Fatigue domain in order to establish the fatigue limits associated with each level of pre-damage. Results evidence that, in the case of polished samples, an important number of cycles is required to initiate surface cracks ant then to affect the fatigue limit of the material but, in the case of ground samples, a few number of cycles is sufficient to initiate cracks and to critically decrease the fatigue limit. The fatigue limit of pre-damaged samples can be estimated using the stress intensity factor threshold. Moreover, this detrimental effect of severe surface conditions is enhanced when fatigue tests are performed under a positive mean stress (author)

  13. On the reversed Brayton cycle with high speed machinery

    Energy Technology Data Exchange (ETDEWEB)

    Backman, J.

    1996-12-31

    This work was carried out in the laboratory of Fluid Dynamics, at Lappeenranta University of Technology during the years 1991-1996. The research was a part of larger high speed technology development research. First, there was the idea of making high speed machinery applications with the Brayton cycle. There was a clear need to deepen the knowledge of the cycle itself and to make a new approach in the field of the research. Also, the removal of water from the humid air seemed very interesting. The goal of this work was to study methods of designing high speed machinery for the reversed Brayton cycle, from theoretical principles to practical applications. The reversed Brayton cycle can be employed as an air dryer, a heat pump or a refrigerating machine. In this research the use of humid air as a working fluid has an environmental advantage, as well. A new calculation method for the Brayton cycle is developed. In this method especially the expansion process in the turbine is important because of the condensation of the water vapour in the humid air. This physical phenomena can have significant effects on the level of performance of the application. Also, the influence of calculating the process with actual, achievable process equipment efficiencies is essential for the development of future machinery. The above theoretical calculations are confirmed with two different laboratory prototypes. (53 refs.)

  14. On the reversed Brayton cycle with high speed machinery

    Energy Technology Data Exchange (ETDEWEB)

    Backman, J

    1997-12-31

    This work was carried out in the laboratory of Fluid Dynamics, at Lappeenranta University of Technology during the years 1991-1996. The research was a part of larger high speed technology development research. First, there was the idea of making high speed machinery applications with the Brayton cycle. There was a clear need to deepen the knowledge of the cycle itself and to make a new approach in the field of the research. Also, the removal of water from the humid air seemed very interesting. The goal of this work was to study methods of designing high speed machinery for the reversed Brayton cycle, from theoretical principles to practical applications. The reversed Brayton cycle can be employed as an air dryer, a heat pump or a refrigerating machine. In this research the use of humid air as a working fluid has an environmental advantage, as well. A new calculation method for the Brayton cycle is developed. In this method especially the expansion process in the turbine is important because of the condensation of the water vapour in the humid air. This physical phenomena can have significant effects on the level of performance of the application. Also, the influence of calculating the process with actual, achievable process equipment efficiencies is essential for the development of future machinery. The above theoretical calculations are confirmed with two different laboratory prototypes. (53 refs.)

  15. A New, Highly Improved Two-Cycle Engine

    Science.gov (United States)

    Wiesen, Bernard

    2008-01-01

    The figure presents a cross-sectional view of a supercharged, variable-compression, two-cycle, internal-combustion engine that offers significant advantages over prior such engines. The improvements are embodied in a combination of design changes that contribute synergistically to improvements in performance and economy. Although the combination of design changes and the principles underlying them are complex, one of the main effects of the changes on the overall engine design is reduced (relative to prior two-cycle designs) mechanical complexity, which translates directly to reduced manufacturing cost and increased reliability. Other benefits include increases in the efficiency of both scavenging and supercharging. The improvements retain the simplicity and other advantages of two-cycle engines while affording increases in volumetric efficiency and performance across a wide range of operating conditions that, heretofore have been accessible to four-cycle engines but not to conventionally scavenged two-cycle ones, thereby increasing the range of usefulness of the two-cycle engine into all areas now dominated by the four-cycle engine. The design changes and benefits are too numerous to describe here in detail, but it is possible to summarize the major improvements: Reciprocating Shuttle Inlet Valve The entire reciprocating shuttle inlet valve and its operating gear is constructed as a single member. The shuttle valve is actuated in a lost-motion arrangement in which, at the ends of its stroke, projections on the shuttle valve come to rest against abutments at the ends of grooves in a piston skirt. This shuttle-valve design obviates the customary complex valve mechanism, actuated from an engine crankshaft or camshaft, yet it is effective with every type of two-cycle engine, from small high-speed single cylinder model engines, to large low-speed multiple cylinder engines.

  16. On-board emission measurement of high-loaded light-duty vehicles in Algeria.

    Science.gov (United States)

    Boughedaoui, Ménouèr; Kerbachi, Rabah; Joumard, Robert

    2008-01-01

    A sample of eight private gasoline and diesel conventional light-duty vehicles (LDVs) in use with various ages, carrying a load of 460 kg, were tested on a representative trip in the traffic flow of the city of Blida to obtain emission factors representing the actual use conditions of Algerian LDVs. The gas sampling system (mini-constant volume sampling) as well as the analyzers are carried on-board the vehicle. Around 55 tests were conducted during 3 months covering more than 480 km under various real driving conditions. The mean speed downtown is about 16.1 km/hr with a rather low acceleration, an average of 0.60 m/sec2. For each test, kinematics are recorded as well as the analysis of the four emitted pollutants carbon dioxide, carbon monoxide, oxides of nitrogen, and total hydrocarbons. Emission factors were evaluated according to speed for each category of gasoline and diesel engines. The influence of some parameters such as cold/hot start, age of vehicle and its state of maintenance are discussed. Results are compared with the European database ARTEMIS for comparable vehicles. These measurements contribute to the development of unit emission of the vehicles used in Algeria, which are necessary for the calculation of emission inventory of pollutants and greenhouse gases from the road transportation sector. The unit emissions constitute a tool of decisionmaking aid regarding the conception of new regulations of vehicle control and inspection in Algeria and even in similar developing countries.

  17. High-Energy Solar Particle Events in Cycle 24

    Science.gov (United States)

    Gopalswamy, N.; Makela, P.; Yashiro, S.; Xie, H.; Akiyama, S.; Thakur, N.

    2015-01-01

    The Sun is already in the declining phase of cycle 24, but the paucity of high-energy solar energetic particle (SEP) events continues with only two ground level enhancement (GLE) events as of March 31, 2015. In an attempt to understand this, we considered all the large SEP events of cycle 24 that occurred until the end of 2014. We compared the properties of the associated CMEs with those in cycle 23. We found that the CME speeds in the sky plane were similar, but almost all those cycle-24 CMEs were halos. A significant fraction of (16%) of the frontside SEP events were associated with eruptive prominence events. CMEs associated with filament eruption events accelerate slowly and attain peak speeds beyond the typical GLE release heights. When we considered only western hemispheric events that had good connectivity to the CME nose, there were only 8 events that could be considered as GLE candidates. One turned out to be the first GLE event of cycle 24 (2012 May 17). In two events, the CMEs were very fast (>2000 km/s) but they were launched into a tenuous medium (high Alfven speed). In the remaining five events, the speeds were well below the typical GLE CME speed (2000 km/s). Furthermore, the CMEs attained their peak speeds beyond the typical heights where GLE particles are released. We conclude that several factors contribute to the low rate of high-energy SEP events in cycle 24: (i) reduced efficiency of shock acceleration (weak heliospheric magnetic field), (ii) poor latitudinal and longitudinal connectivity), and (iii) variation in local ambient conditions (e.g., high Alfven speed).

  18. Heat exchangers for high-temperature thermodynamic cycles

    International Nuclear Information System (INIS)

    Fraas, A.P.

    1975-01-01

    The special requirements of heat exchangers for high temperature thermodynamic cycles are outlined and discussed with particular emphasis on cost and thermal stress problems. Typical approaches that have been taken to a comprehensive solution intended to meet all of the many boundary conditions are then considered by examining seven typical designs including liquid-to-liquid heat exchangers for nuclear plants, a heater for a closed cycle gas turbine coupled to a fluidized bed coal combustion chamber, steam generators for nuclear plants, a fossil fuel-fired potassium boiler, and a potassium condenser-steam generator. (auth)

  19. The development and chemistry of high efficiency combined cycle plants

    International Nuclear Information System (INIS)

    Svoboda, Robert

    1999-01-01

    This paper presents a boiler concept based on the combination of a low-pressure drum-type boiler with high-pressure once-through boiler and the appropriate water/steam cycle. An all volatile treatment is used in the low-pressure boiler and oxygenated treatment for the once-through high pressure system. Impurity control is achieved by adapted system design and materials, high quality make-up, an appropriate cleanliness concept and clean-up procedures for a cold start. Cycle refreshing is realized by blowdown from the high-pressure water-separator. This concept utilizes simper and less equipment than traditional solutions, resulting in increased power plant reliability and less requirement on maintenance and on capital cost [it

  20. On-road heavy-duty diesel particulate matter emissions modeled using chassis dynamometer data.

    Science.gov (United States)

    Kear, Tom; Niemeier, D A

    2006-12-15

    This study presents a model, derived from chassis dynamometer test data, for factors (operational correction factors, or OCFs) that correct (g/mi) heavy-duty diesel particle emission rates measured on standard test cycles for real-world conditions. Using a random effects mixed regression model with data from 531 tests of 34 heavy-duty vehicles from the Coordinating Research Council's E55/E59 research project, we specify a model with covariates that characterize high power transient driving, time spent idling, and average speed. Gram per mile particle emissions rates were negatively correlated with high power transient driving, average speed, and time idling. The new model is capable of predicting relative changes in g/mi on-road heavy-duty diesel particle emission rates for real-world driving conditions that are not reflected in the driving cycles used to test heavy-duty vehicles.

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

    Science.gov (United States)

    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.

  2. Effects of high mean stress on the high-cycle fatigue behavior of PWA 1480

    International Nuclear Information System (INIS)

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

    1985-03-01

    PWA 1480 is a potential candidate material for use in the high-pressure fuel turbine blade of the Space Shuttle Main Engine. As an engine material it will be subjected to high-cycle fatigue loading superimposed on a high mean stress due to combined centrifugal and thermal loadings. This paper describes results obtained in an ongoing program to determine the effects of a high mean stress on the high-cycle fatigue behavior of this material

  3. 49 CFR 542.1 - Procedures for selecting new light duty truck lines that are likely to have high or low theft rates.

    Science.gov (United States)

    2010-10-01

    ... lines that are likely to have high or low theft rates. 542.1 Section 542.1 Transportation Other... OF TRANSPORTATION PROCEDURES FOR SELECTING LIGHT DUTY TRUCK LINES TO BE COVERED BY THE THEFT... or low theft rates. (a) Scope. This section sets forth the procedures for motor vehicle manufacturers...

  4. High efficiency Dual-Cycle Conversion System using Kr-85.

    Science.gov (United States)

    Prelas, Mark A; Tchouaso, Modeste Tchakoua

    2018-04-26

    This paper discusses the use of one of the safest isotopes known isotopes, Kr-85, as a candidate fuel source for deep space missions. This isotope comes from 0.286% of fission events. There is a vast quantity of Kr-85 stored in spent fuel and it is continually being produced by nuclear reactors. In using Kr-85 with a novel Dual Cycle Conversion System (DCCS) it is feasible to boost the system efficiency from 26% to 45% over a single cycle device while only increasing the system mass by less than 1%. The Kr-85 isotope is the ideal fuel for a Photon Intermediate Direct Energy Conversion (PIDEC) system. PIDEC is an excellent choice for the top cycle in a DCCS. In the top cycle, ionization and excitation of the Kr-85:Cl gas mixture (99% Kr and 1% Cl) from beta particles creates KrCl* excimer photons which are efficiently absorbed by diamond photovoltaic cells on the walls of the pressure vessels. The benefit of using the DCCS is that Kr-85 is capable of operating at high temperatures in the primary cycle and the residual heat can then be converted into electrical power in the bottom cycle which uses a Stirling Engine. The design of the DCCS begins with a spherical pressure vessel of radius 13.7 cm with 3.7 cm thick walls and is filled with a Kr-85:Cl gas mixture. The inner wall has diamond photovoltaic cells attached to it and there is a sapphire window between the diamond photovoltaic cells and the Kr-85:Cl gas mixture which shields the photovoltaic cells from beta particles. The DCCS without a gamma ray shield has specific power of 6.49 W/kg. A removable 6 cm thick tungsten shield is used to safely limit the radiation exposure levels of personnel. A shadow shield remains in the payload to protect the radiation sensitive components in the flight package. The estimated specific power of the unoptimized system design in this paper is about 2.33 W/kg. The specific power of an optimized system should be higher. The Kr-85 isotope is relatively safe because it

  5. Building High-Performing and Improving Education Systems. Systems and Structures: Powers, Duties and Funding. Review

    Science.gov (United States)

    Slater, Liz

    2013-01-01

    This Review looks at the way high-performing and improving education systems share out power and responsibility. Resources--in the form of funding, capital investment or payment of salaries and other ongoing costs--are some of the main levers used to make policy happen, but are not a substitute for well thought-through and appropriate policy…

  6. Highly efficient 6-stroke engine cycle with water injection

    Science.gov (United States)

    Szybist, James P; Conklin, James C

    2012-10-23

    A six-stroke engine cycle having improved efficiency. Heat is recovered from the engine combustion gases by using a 6-stroke engine cycle in which combustion gases are partially vented proximate the bottom-dead-center position of the fourth stroke cycle, and water is injected proximate the top-dead-center position of the fourth stroke cycle.

  7. High cycle fatigue of Type 422 stainless steel

    International Nuclear Information System (INIS)

    Soo, P.; Chow, J.G.Y.; Sabatini, R.L.

    1978-01-01

    High cycle fatigue testing has been carried out on Type 422 stainless steel to determine the performance of cyclically stressed disks and blades in the main and auxiliary HTGR helium circulators. Tests were performed at 316, 482, and 538 0 C (600, 900, and 1000 0 F) in air for the fully reversible and mean load conditions. Goodman's analysis is shown to be valid in predicting failure at 316 0 C (600 0 F), marginally valid at 482 0 C (900 0 F), and probably invalid at 538 0 C (1000 0 F). Metallographic analyses were conducted to characterize the nature of failure for the temperatures and loading conditions investigated

  8. Public high school teachers opinions on school administrators supervision duty in Turkey

    Directory of Open Access Journals (Sweden)

    Nurhayat Celebi

    2010-09-01

    Full Text Available Supervision that has been conducted by public high school administrators plays a major role in the effectiveness of a school.Lack of having well defined criteria is thought to be causing some major problems in the educational environment. Subjectivity,administrative policy constraints, lack of teacher motivation and lack of job satisfaction are only a few examples of those kindsof problems. The study, which is based on the scanning model and a descriptive research, was performed on 303 teachersworking in randomly chosen high schools in the Bakırköy district of İstanbul. The data collection instrument was developed bythe researcher. The confirmatory factor analysis test was used to determine whether the scale confirm to the factor structureor not. It was noticed that the factor structure could be explained with 5 factor sub-dimensions, and accordingly, the measuringscale, which had been originally prepared in 45 items, was modified and reduced to 32 items. As a result of factor analysis, thefactors were confirmed as follows; “the leadership, supervision techniques, effective supervision, efficacy of administration andteaching quality”. All these factors are explain about 48 % for total test variance. Cronbach alpha internal consistency factorwhich has been calculated according to the reliability analysis and it’s value was ,90. Factor loadings of sub- dimensions arebetween ,41 and ,81. In accordance with the results, training programs must be applied regularly to the administrators in orderto enable them to acquire more supervision attitude and to increase the efficiency and quality levels of the schools

  9. High duty factor Plasma Generator for CERN’s Superconducting Proton Linac

    CERN Document Server

    Lettry, J; Scrivens, R; Chaudet, E; Faircloth, D; Favre, G; Geisser, JM; Kuchler, D; Mathot, S; Midttun, O; Paoluzzi, M; Schmitzer, C; Steyaert, D

    2010-01-01

    CERN’s Linac4 is a 160 MeV linear accelerator currently under construction. It will inject negatively charged hydrogen ions into CERN’s PS-Booster. Its ion source is a non-cesiated RF driven H- volume source directly inspired from the one of DESY and is aimed to deliver pulses of 80 mA of H- during 0.4 ms at a 2 Hz repetition rate. The Superconducting Proton Linac (SPL) project is part of the luminosity upgrade of the LHC, it consists of an extension of Linac4 up to 5 GeV and is foreseen to deliver protons to a future 50 GeV Synchrotron (PS2). For the SPL high power option (HP-SPL), the ion source would deliver pulses of 80 mA of H- during 1.2 ms and operate at a 50 Hz repetition rate. This significant upgrade motivates the design of the new water cooled plasma generator presented in this paper. Its engineering is based on the results of a finite element thermal study of the Linac4 H- plasma generator that identified critical components and thermal barriers. A cooling system is proposed which achieves the...

  10. A model for high-cycle fatigue crack propagation

    Energy Technology Data Exchange (ETDEWEB)

    Balbi, Marcela Angela [Rosario National Univ. (Argentina); National Council of Scientific Research and Technology (CONICET) (Argentina)

    2017-02-01

    This paper deals with the prediction of high-cycle fatigue behavior for four different materials (7075-T6 alloy, Ti-6Al-4 V alloy, JIS S10C steel and 0.4 wt.-% C steel) using Chapetti's approach to estimate the fatigue crack propagation curve. In the first part of the paper, a single integral equation for studying the entire propagation process is determined using the recent results of Santus and Taylor, which consider a double regime of propagation (short and long cracks) characterized by the model of El Haddad. The second part of the paper includes a comparison of the crack propagation behavior model proposed by Navarro and de los Rios with the one mentioned in the first half of this work. The results allow us to conclude that the approach presented in this paper is a good and valid estimation of high-cycle fatigue crack propagation using a single equation to describe the entire fatigue crack regime.

  11. A brief review study of various thermodynamic cycles for high temperature power generation systems

    International Nuclear Information System (INIS)

    Yu, Si-Cong; Chen, Lin; Zhao, Yan; Li, Hong-Xu; Zhang, Xin-Rong

    2015-01-01

    Highlights: • Various high temperature power generation cycles for are reviewed and analyzed. • The operating temperature is higher than 700 K for high temperature power systems. • Thermodynamic cycle model study and working fluid choices are discussed. • Characteristics and future developments of high temperature cycles are presented and compared. - Abstract: This paper presents a review of the previous studies and papers about various thermodynamic cycles working for high temperature power generation procedures, in these cycles the highest temperature is not lower than 700 K. Thermodynamic cycles that working for power generation are divided into two broad categories, thermodynamic cycle model study and working fluid analysis. Thermodynamic cycle contains the simple cycle model and the complex cycle model, emphasis has been given on the complex thermodynamic cycles due to their high thermal efficiencies. Working fluids used for high temperature thermodynamic cycles is a dense gas rather than a liquid. A suitable thermodynamic cycle is crucial for effectively power generation especially under the condition of high temperature. The main purpose is to find out the characteristics of various thermodynamic cycles when they are working in the high temperature region for power generation. As this study shows, combined cycles with both renewable and nonrenewable energies as the heat source can show good performance

  12. A high efficiency 10 kWe microcogenerator based on an Atkinson cycle internal combustion engine

    International Nuclear Information System (INIS)

    Capaldi, Pietro

    2014-01-01

    The paper focuses on the design and the overall performance of a 10 kW electric power microcogeneration plant suitable for local energy production, based on an Atkinson-cycle internal combustion engine prototype and entirely set by Istituto Motori of the Italian National Research Council. The engine was originally a wide-spread Diesel automotive unit, then converted into a methane spark ignition system and finally modified to perform an Atkinson/Miller cycle with an extended expansion, capable of a higher global efficiency and low gaseous emissions. The paper starts by defining the ratio which leaded to this specific choice among many other automotive and industrial engines, in order to obtain a reliable, long endurance, cost effective, high efficiency base, suitable for microcogeneration in residential or commercial applications. The new engine has been coupled with a liquid cooled induction generator, a set of heat exchangers and finally placed in a sealed containing case, to reduce both noise emission and heat losses. Then the plant has been tested as an electricity and heat production system, ready for grid connection thanks to a new designed management/control system. During endurance test a complete description of its functioning behaviour has been given. - Highlights: • A new high efficiency microcogenerator based on an Atkinson/Miller cycle engine. • Atkinson cycle together with stoichiometric operation deliver better performance. • A cost-effective microcogenerator based on widespread elements (automotive engine). • The chosen automotive engine has heavy duty characteristics (Diesel derived). • A conversion criteria from a Diesel to an Atkinson cycle engine was individuated

  13. A comparison between thorium-uranium and low enrichment uranium cycles in the high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cerles, J M

    1973-03-15

    In a previous report, it was shown that the Uranium cycle could be used as well with multi-hole block (GGA type) as with tubular elements. Now, in a F.S.V. geometry, a comparison is made between Thorium cycle and Uranium cycle. This comparison will be concerned with the physical properties of the materials, the needs of natural Uranium, the fissile material inventory and, at last, an attempt of economical considerations. In this report the cycle will be characterizd by the fertile material. So, we write ''Thorium cycle'' for Highly Enriched Uranium - Thorium cycle and ''Uranium cycle'' for low Enrichment Uranium cycle.

  14. Pedalling rate affects endurance performance during high-intensity cycling

    DEFF Research Database (Denmark)

    Nielsen, Jens Steen; Hansen, Ernst Albin; Sjøgaard, Gisela

    2004-01-01

    The purpose of this study into high-intensity cycling was to: (1) test the hypothesis that endurance time is longest at a freely chosen pedalling rate (FCPR), compared to pedalling rates 25% lower (FCPR-25) and higher (FCPR+25) than FCPR, and (2) investigate how physiological variables......, and endurance time at W90 with FCPR-25, FCPR, and FCPR+25. Power reserve was calculated as the difference between applied power output at a given pedalling rate and peak crank power at this same pedalling rate. W90 was 325 (47) W. FCPR at W90 was 78 (11) rpm, resulting in FCPR-25 being 59 (8) rpm and FCPR+25...... time was negatively related to VO(2max), W90 and % MHC I, while positively related to power reserve. In conclusion, at group level, endurance time was longer at FCPR and at a pedalling rate 25% lower compared to a pedalling rate 25% higher than FCPR. Further, inter-individual physiological variables...

  15. Closed cycle high-repetition-rate pulsed HF laser

    Science.gov (United States)

    Harris, Michael R.; Morris, A. V.; Gorton, Eric K.

    1997-04-01

    The design and performance of a closed cycle high repetition rate HF laser is described. A short pulse, glow discharge is formed in a 10 SF6:1 H2 gas mixture at a total pressure of approximately 110 torr within a 15 by 0.5 by 0.5 cm3 volume. Transverse, recirculated gas flow adequate to enable repetitive operation up to 3 kHz is imposed by a centrifugal fan. The fan also forces the gas through a scrubber cell to eliminate ground state HF from the gas stream. An automated gas make-up system replenishes spent gas removed by the scrubber. Typical mean laser output powers up to 3 W can be maintained for extended periods of operation.

  16. Modeling real-world fuel consumption and carbon dioxide emissions with high resolution for light-duty passenger vehicles in a traffic populated city

    International Nuclear Information System (INIS)

    Zhang, Shaojun; Wu, Ye; Un, Puikei; Fu, Lixin; Hao, Jiming

    2016-01-01

    Modeling fuel consumption of light-duty passenger vehicles has created substantial concerns due to the uncertainty from real-world operating conditions. Macao is world-renowned for its tourism industry and high population density. An empirical model is developed to estimate real-world fuel consumption and carbon dioxide emissions for gasoline-powered light-duty passenger vehicles in Macao by considering local fleet configuration and operating conditions. Thanks to increasingly stringent fuel consumption limits in vehicle manufacturing countries, estimated type-approval fuel consumption for light-duty passenger vehicles in Macao by model year was reduced from 7.4 L/100 km in 1995 to 5.9 L/100 km in 2012, although a significant upsizing trend has considerably offset potential energy-saving benefit. However, lower driving speed and the air-conditioning usage tend to raise fleet-average fuel consumption and carbon dioxide emission factors, which are estimated to be 10.1 L/100 km and 240 g/km in 2010. Fleet-total fuel consumption and carbon dioxide emissions are modeled through registered vehicle population-based and link-level traffic demand approaches and the results satisfactorily coincide with the historical record of fuel sales in Macao. Temporal and spatial variations in fuel consumption and carbon dioxide emissions from light-duty passenger vehicles further highlight the importance of effective traffic management in congested areas of Macao. - Highlights: • A fuel consumption model is developed for Macao's light-duty passenger cars. • Increased vehicle size partially offset energy benefit from tightened fuel consumption standard. • Lower speed and use of air-conditioning greatly increase fuel use of Macao light-duty passenger cars. • A high resolution inventory of fuel use and carbon dioxide emissions is built with link-level traffic data. • Policy suggestions are provided to mitigate fuel use in a traffic populated city.

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

    Science.gov (United States)

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

    1985-01-01

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

  18. Study on thermodynamic cycle of high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Qu Xinhe; Yang Xiaoyong; Wang Jie

    2017-01-01

    The development trend of the (very) High temperature gas-cooled reactor is to gradually increase the reactor outlet temperature. The different power conversion units are required at the different reactor outlet temperature. In this paper, for the helium turbine direct cycle and the combined cycle of the power conversion unit of the High temperature gas-cooled reactor, the mathematic models are established, and three cycle plans are designed. The helium turbine direct cycle is a Brayton cycle with recuperator, precooler and intercooler. In the combined cycle plan 1, the topping cycle is a simple Brayton cycle without recuperator, precooler and intercooler, and the bottoming cycle is based on the steam parameters (540deg, 6 MPa) recommended by Siemens. In the combined cycle plan 2, the topping cycle also is a simple Brayton cycle, and the bottoming cycle which is a Rankine cycle with reheating cycle is based on the steam parameters of conventional subcritical thermal power generation (540degC, 18 MPa). The optimization results showed that the cycle efficiency of the combined cycle plan 2 is the highest, the second is the helium turbine direct cycle, and the combined cycle plan 2 is the lowest. When the reactor outlet temperature is 900degC and the pressure ratio is 2.02, the cycle efficiency of the combined cycle plan 2 can reach 49.7%. The helium turbine direct cycle has a reactor inlet temperature above 500degC due to the regenerating cycle, so it requires a cooling circuit for the internal wall of the reactor pressure vessel. When the reactor outlet temperature increases, the increase of the pressure ratio required by the helium turbine direct cycle increases may bring some difficulties to the design and manufacture of the magnetic bearings. For the combined cycle, the reactor inlet temperature can be controlled below than 370degC, so the reactor pressure vessel can use SA533 steel without cooling the internal wall of the reactor pressure vessel. The pressure

  19. Business cycle and innovation activity in medium-high and high technology industry in Poland

    Directory of Open Access Journals (Sweden)

    Dzikowski Piotr

    2015-12-01

    Full Text Available This article examines differences in an impact of business cycle phases on innovation activity in medium-high and high technology industry in Poland. It is assumed that each business cycle phase influences innovation activity in the same fashion, but its impact varies and it depends on the firm’s innovation activity. The higher innovation activity the less impact of business cycle. The scope of the survey relates to innovation in MHT and HT industry in Poland. The data concerns the innovation at the firm level and the diffusion “new for the company”. Innovation activity is defined by the following activities: (1 expenditure on research and development and investments in fixed assets not used so far such as: abuildings, premises and land; b machinery and equipment, c computer software; (2 implementation of new products and technological processes and (3 innovation cooperation. The methodological part of the analysis includes a logit modeling. The survey includes 1355 companies. Business cycle has a great influence on innovation activity in MTH and HT industry in Poland. The influence of recovery phase is positive whereas both stagnation and recession phases decrease the probability of innovation activity. The character of influence depends on the propensity to take innovation activity. The higher level of innovation activity the enterprises present the less influence of business cycle they get.

  20. Microfluidic sensor for ultra high redox cycling amplification for highly selective electrochemical measurements

    NARCIS (Netherlands)

    Odijk, Mathieu; Straver, Martin; Olthuis, Wouter; van den Berg, Albert

    2011-01-01

    In this contribution a SU8/glass-based microfluidic sensor is described with two closely spaced parallel electrodes for highly selective measurements using the redox cycling (RC) effect. Using this sensor, a RC amplification of ~2000x is measured using the ferrocyanide redox couple, which is much

  1. A study on different thermodynamic cycle schemes coupled with a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Qu, Xinhe; Yang, Xiaoyong; Wang, Jie

    2017-01-01

    Highlights: • The features of three different power generation schemes, including closed Brayton cycle, non-reheating combined cycle and reheating combined cycle, coupled with high temperature gas-cooled reactor (HTGR) were investigated and compared. • The effects and mechanism of reactor core outlet temperature, compression ratio and other key parameters over cycle characteristics were analyzed by the thermodynamic models.. • It is found that reheated combined cycle has the highest efficiency. Reactor outlet temperature and main steam parameters are key factors to improve the cycle’s performance. - Abstract: With gradual increase in reactor outlet temperature, the efficient power conversion technology has become one of developing trends of (very) high temperature gas-cooled reactors (HTGRs). In this paper, different cycle power generation schemes for HTGRs were systematically studied. Physical and mathematical models were established for these three cycle schemes: closed Brayton cycle, simple combined cycle, and reheated combined cycle. The effects and mechanism of key parameters such as reactor core outlet temperature, reactor core inlet temperature and compression ratio on the features of these cycles were analyzed. Then, optimization results were given with engineering restrictive conditions, including pinch point temperature differences. Results revealed that within the temperature range of HTGRs (700–900 °C), the reheated combined cycle had the highest efficiency, while the simple combined cycle had the lowest efficiency (900 °C). The efficiencies of the closed Brayton cycle, simple combined cycle and reheated combined cycle are 49.5%, 46.6% and 50.1%, respectively. These results provide insights on the different schemes of these cycles, and reveal the effects of key parameters on performance of these cycles. It could be helpful to understand and develop a combined cycle coupled with a high temperature reactor in the future.

  2. Large motion high cycle high speed optical fibers for space based applications.

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Peter G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tandon, Rajan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gibson, Cory S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reedlunn, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rasberry, Roger David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rohr, Garth David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    Future remote sensing applications will require higher resolution and therefore higher data rates (up to perhaps 100 gigabits per second) while achieving lower mass and cost. A current limitation to the design space is high speed high bandwidth data does not cross movable gimbals because of cabling issues. This requires the detectors to be off gimbal. The ability to get data across the gimbal would open up efficiencies in designs where the detectors and the electronics can be placed anywhere on the system. Fiber optic cables provide light weight high speed high bandwidth connections. Current options are limited to 20,000 cycles as opposed to the 1,000,000 cycles needed for future space based applications. To extend this to the million+ regime, requires a thorough understanding of the failure mechanisms and the materials, proper selection of materials (e.g., glass and jacket material) allowable geometry changes to the cable, radiation hardness, etc.

  3. Thermally Induced Ultra High Cycle Fatigue of Copper Alloys of the High Gradient Accelerating Structures

    CERN Document Server

    Heikkinen, Samuli; Wuensch, Walter

    2010-01-01

    In order to keep the overall length of the compact linear collider (CLIC), currently being studied at the European Organization for Nuclear Research (CERN), within reasonable limits, i.e. less than 50 km, an accelerating gradient above 100 MV/m is required. This imposes considerable demands on the materials of the accelerating structures. The internal surfaces of these core components of a linear accelerator are exposed to pulsed radio frequency (RF) currents resulting in cyclic thermal stresses expected to cause surface damage by fatigue. The designed lifetime of CLIC is 20 years, which results in a number of thermal stress cycles of the order of 2.33•1010. Since no fatigue data existed in the literature for CLIC parameter space, a set of three complementary experiments were initiated: ultra high cycle mechanical fatigue by ultrasound, low cycle fatigue by pulsed laser irradiation and low cycle thermal fatigue by high power microwaves, each test representing a subset of the original problem. High conductiv...

  4. High Cycle Fatigue Damage Mechanisms of MAR-M 247 Superalloy at High Temperatures

    Czech Academy of Sciences Publication Activity Database

    Šmíd, Miroslav; Horník, Vít; Hutař, Pavel; Hrbáček, K.; Kunz, Ludvík

    2016-01-01

    Roč. 69, č. 2 (2016), s. 393-397 ISSN 0972-2815 R&D Projects: GA TA ČR(CZ) TA04011525; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : High cycle fatigue * S-N curves * Fractography * High temperature * EBSD analysis Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.533, year: 2016

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

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Robin [SAIC; Davenport, Roger [SAIC; Talbot, Jan [UCSD; Herz, Richard [UCSD; Genders, David [Electrosynthesis Co.; Symons, Peter [Electrosynthesis Co.; Brown, Lloyd [TChemE

    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

  6. Future methane emissions from the heavy-duty natural gas transportation sector for stasis, high, medium, and low scenarios in 2035.

    Science.gov (United States)

    Clark, Nigel N; Johnson, Derek R; McKain, David L; Wayne, W Scott; Li, Hailin; Rudek, Joseph; Mongold, Ronald A; Sandoval, Cesar; Covington, April N; Hailer, John T

    2017-12-01

    Today's heavy-duty natural gas-fueled fleet is estimated to represent less than 2% of the total fleet. However, over the next couple of decades, predictions are that the percentage could grow to represent as much as 50%. Although fueling switching to natural gas could provide a climate benefit relative to diesel fuel, the potential for emissions of methane (a potent greenhouse gas) from natural gas-fueled vehicles has been identified as a concern. Since today's heavy-duty natural gas-fueled fleet penetration is low, today's total fleet-wide emissions will be also be low regardless of per vehicle emissions. However, predicted growth could result in a significant quantity of methane emissions. To evaluate this potential and identify effective options for minimizing emissions, future growth scenarios of heavy-duty natural gas-fueled vehicles, and compressed natural gas and liquefied natural gas fueling stations that serve them, have been developed for 2035, when the populations could be significant. The scenarios rely on the most recent measurement campaign of the latest manufactured technology, equipment, and vehicles reported in a companion paper as well as projections of technology and practice advances. These "pump-to-wheels"(PTW) projections do not include methane emissions outside of the bounds of the vehicles and fuel stations themselves and should not be confused with a complete wells-to-wheels analysis. Stasis, high, medium, and low scenario PTW emissions projections for 2035 were 1.32%, 0.67%, 0.33%, and 0.15% of the fuel used. The scenarios highlight that a large emissions reductions could be realized with closed crankcase operation, improved best practices, and implementation of vent mitigation technologies. Recognition of the potential pathways for emissions reductions could further enhance the heavy-duty transportation sectors ability to reduce carbon emissions. Newly collected pump-to-wheels methane emissions data for current natural gas technologies

  7. Fuel rod behaviour at high burnup WWER fuel cycles

    International Nuclear Information System (INIS)

    Medvedev, A.; Bogatyr, S.; Kouznetsov, V.; Khvostov, G.; Lagovsky; Korystin, L.; Poudov, V.

    2003-01-01

    The modernisation of WWER fuel cycles is carried out on the base of complete modelling and experimental justification of fuel rods up to 70 MWd/kgU. The modelling justification of the reliability of fuel rod and fuel rod with gadolinium is carried out with the use of certified START-3 code. START-3 code has a continuous experimental support. The thermophysical and strength reliability of WWER-440 fuel is justified for fuel rod and pellet burnups 65 MWd/kgU and 74 MWd/U, accordingly. Results of analysis are demonstrated by the example of uranium-gadolinium fuel assemblies of second generation under 5-year cycle with a portion of 6-year assemblies and by the example of successfully completed pilot operation of 5-year cycle fuel assemblies during 6 years at unit 3 of Kolskaja NPP. The thermophysical and strength reliability of WWER-1000 fuel is justified for a fuel rod burnup 66 MWd/kgU by the example of fuel operation under 4-year cycles and 6-year test operation of fuel assemblies at unit 1 of Kalininskaya NPP. By the example of 5-year cycle at Dukovany NPP Unit 2 it was demonstrated that WWER fuel rod of a burnup 58 MWd/kgU ensure reliable operation under load following conditions. The analysis has confirmed sufficient reserves of Russian fuel to implement program of JSC 'TVEL' in order to improve technical and economical parameters of WWER fuel cycles

  8. Competition between microstructure and defect in multiaxial high cycle fatigue

    Directory of Open Access Journals (Sweden)

    F. Morel

    2015-07-01

    Full Text Available This study aims at providing a better understanding of the effects of both microstructure and defect on the high cycle fatigue behavior of metallic alloys using finite element simulations of polycrystalline aggregates. It is well known that the microstructure strongly affects the average fatigue strength and when the cyclic stress level is close to the fatigue limit, it is often seen as the main source of the huge scatter generally observed in this fatigue regime. The presence of geometrical defects in a material can also strongly alter the fatigue behavior. Nonetheless, when the defect size is small enough, i.e. under a critical value, the fatigue strength is no more affected by the defect. The so-called Kitagawa effect can be interpreted as a competition between the crack initiation mechanisms governed either by the microstructure or by the defect. Surprisingly, only few studies have been done to date to explain the Kitagawa effect from the point of view of this competition, even though this effect has been extensively investigated in the literature. The primary focus of this paper is hence on the use of both FE simulations and explicit descriptions of the microstructure to get insight into how the competition between defect and microstructure operates in HCF. In order to account for the variability of the microstructure in the predictions of the macroscopic fatigue limits, several configurations of crystalline orientations, crystal aggregates and defects are studied. The results of each individual FE simulation are used to assess the response at the macroscopic scale thanks to a probabilistic fatigue criterion proposed by the authors in previous works. The ability of this criterion to predict the influence of defects on the average and the scatter of macroscopic fatigue limits is evaluated. In this paper, particular emphasis is also placed on the effect of different loading modes (pure tension, pure torsion and combined tension and torsion on

  9. Tensile and high cycle fatigue behaviors of high-Mn steels at 298 and 110 K

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Wongyu; Jeong, Daeho; Sung, Hyokyung; Kim, Sangshik, E-mail: sang@gnu.ac.kr

    2017-02-15

    Tensile and high cycle fatigue behaviors of high-Mn austenitic steels, including 25Mn, 25Mn0.2Al, 25Mn0.5Cu, 24Mn4Cr, 22Mn3Cr and 16Mn2Al specimens, were investigated at 298 and 110 K. Depending on the alloying elements, tensile ductility of high-Mn steels either increased or decreased with decreasing temperature from 298 to 110 K. Reasonable correlation between the tendency for martensitic tranformation, the critical twinning stress and the percent change in tensile elongation suggested that tensile deformation of high-Mn steels was strongly influenced by SFE determining TRIP and TWIP effects. Tensile strength was the most important parameter in determining the resistance to high cycle fatigue of high-Mn steels with an exceptional work hardening capability at room and cryogenic temperatures. The fatigue crack nucleation mechanism in high-Mn steels did not vary with decreasing tempertature, except Cr-added specimens with grain boundary cracking at 298 K and slip band cracking at 110 K. The EBSD (electron backscatter diffraction) analyses suggested that the deformation mechanism under fatigue loading was significantly different from tensile deformation which could be affected by TRIP and TWIP effects. - Highlights: •The resistances to HCF of various high-Mn steels were measured. •The variables affecting tensile and HCF behaviors of high-Mn steels were assessed. •The relationship between tensile and the HCF behaviors of high-Mn steels was established.

  10. eWaterCycle: A high resolution global hydrological model

    Science.gov (United States)

    van de Giesen, Nick; Bierkens, Marc; Drost, Niels; Hut, Rolf; Sutanudjaja, Edwin

    2014-05-01

    In 2013, the eWaterCycle project was started, which has the ambitious goal to run a high resolution global hydrological model. Starting point was the PCR-GLOBWB built by Utrecht University. The software behind this model will partially be re-engineered in order to enable to run it in a High Performance Computing (HPC) environment. The aim is to have a spatial resolution of 1km x 1km. The idea is also to run the model in real-time and forecasting mode, using data assimilation. An on-demand hydraulic model will be available for detailed flow and flood forecasting in support of navigation and disaster management. The project faces a set of scientific challenges. First, to enable the model to run in a HPC environment, model runs were analyzed to examine on which parts of the program most CPU time was spent. These parts were re-coded in Open MPI to allow for parallel processing. Different parallelization strategies are thinkable. In our case, it was decided to use watershed logic as a first step to distribute the analysis. There is rather limited recent experience with HPC in hydrology and there is much to be learned and adjusted, both on the hydrological modeling side and the computer science side. For example, an interesting early observation was that hydrological models are, due to their localized parameterization, much more memory intensive than models of sister-disciplines such as meteorology and oceanography. Because it would be deadly to have to swap information between CPU and hard drive, memory management becomes crucial. A standard Ensemble Kalman Filter (enKF) would, for example, have excessive memory demands. To circumvent these problems, an alternative to the enKF was developed that produces equivalent results. This presentation shows the most recent results from the model, including a 5km x 5km simulation and a proof of concept for the new data assimilation approach. Finally, some early ideas about financial sustainability of an operational global

  11. Very High Cycle Fatigue of Ni-Based Single-Crystal Superalloys at High Temperature

    Science.gov (United States)

    Cervellon, A.; Cormier, J.; Mauget, F.; Hervier, Z.; Nadot, Y.

    2018-05-01

    Very high cycle fatigue (VHCF) properties at high temperature of Ni-based single-crystal (SX) superalloys and of a directionally solidified (DS) superalloy have been investigated at 20 kHz and a temperature of 1000 °C. Under fully reversed conditions (R = - 1), no noticeable difference in VHCF lifetimes between all investigated alloys has been observed. Internal casting pores size is the main VHCF lifetime-controlling factor whatever the chemical composition of the alloys. Other types of microstructural defects (eutectics, carbides), if present, may act as stress concentration sites when the number of cycles exceed 109 cycles or when porosity is absent by applying a prior hot isostatic pressing treatment. For longer tests (> 30 hours), oxidation also controls the main crack initiation sites leading to a mode I crack initiation from oxidized layer. Under such conditions, alloy's resistance to oxidation has a prominent role in controlling the VHCF. When creep damage is present at high ratios (R ≥ 0.8), creep resistance of SX/DS alloys governs VHCF lifetime. Under such high mean stress conditions, SX alloys developed to retard the initiation and creep propagation of mode I micro-cracks from pores have better VHCF lifetimes.

  12. 40 CFR 86.1818-12 - Greenhouse gas emission standards for light-duty vehicles, light-duty trucks, and medium-duty...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Greenhouse gas emission standards for... Complete Otto-Cycle Heavy-Duty Vehicles § 86.1818-12 Greenhouse gas emission standards for light-duty... group of six greenhouse gases: Carbon dioxide, nitrous oxide, methane, hydrofluorocarbons...

  13. High-speed thermal cycling system and method of use

    Science.gov (United States)

    Hansen, A.D.A.; Jaklevic, J.M.

    1996-04-16

    A thermal cycling system and method of use are described. The thermal cycling system is based on the circulation of temperature-controlled water directly to the underside of thin-walled polycarbonate plates. The water flow is selected from a manifold fed by pumps from heated reservoirs. The plate wells are loaded with typically 15-20 microliters of reagent mix for the PCR process. Heat transfer through the thin polycarbonate is sufficiently rapid that the contents reach thermal equilibrium with the water in less than 15 seconds. Complete PCR amplification runs of 40 three-step cycles have been performed in as little as 14.5 minutes, with the results showing substantially enhanced specificity compared to conventional technology requiring run times in excess of 100 minutes. The plate clamping station is designed to be amenable to robotic loading and unloading of the system. It includes a heated lid, thus eliminating the need for mineral oil overlay of the reactants. The present system includes three or more plate holder stations, fed from common reservoirs but operating with independent switching cycles. The system can be modularly expanded. 13 figs.

  14. Alternative ORC bottoming cycles FOR combined cycle power plants

    International Nuclear Information System (INIS)

    Chacartegui, R.; Sanchez, D.; Munoz, J.M.; Sanchez, T.

    2009-01-01

    In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

  15. Parametric studies on different gas turbine cycles for a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Wang Jie; Gu Yihua

    2005-01-01

    The high temperature gas-cooled reactor (HTGR) coupled with turbine cycle is considered as one of the leading candidates for future nuclear power plants. In this paper, the various types of HTGR gas turbine cycles are concluded as three typical cycles of direct cycle, closed indirect cycle and open indirect cycle. Furthermore they are theoretically converted to three Brayton cycles of helium, nitrogen and air. Those three types of Brayton cycles are thermodynamically analyzed and optimized. The results show that the variety of gas affects the cycle pressure ratio more significantly than other cycle parameters, however, the optimized cycle efficiencies of the three Brayton cycles are almost the same. In addition, the turbomachines which are required for the three optimized Brayton cycles are aerodynamically analyzed and compared and their fundamental characteristics are obtained. Helium turbocompressor has lower stage pressure ratio and more stage number than those for nitrogen and air machines, while helium and nitrogen turbocompressors have shorter blade length than that for air machine

  16. Simultaneous monitoring of the two coupled motors of a single FoF1-ATP synthase by three-color FRET using duty cycle-optimized triple-ALEX

    Science.gov (United States)

    Zarrabi, N.; Ernst, S.; Düser, M. G.; Golovina-Leiker, A.; Becker, W.; Erdmann, R.; Dunn, S. D.; Börsch, M.

    2009-02-01

    FoF1-ATP synthase is the enzyme that provides the 'chemical energy currency' adenosine triphosphate, ATP, for living cells. The formation of ATP is accomplished by a stepwise internal rotation of subunits within the enzyme. Briefly, proton translocation through the membrane-bound Fo part of ATP synthase drives a 10-step rotary motion of the ring of c subunits with respect to the non-rotating subunits a and b. This rotation is transmitted to the γ and ɛ subunits of the F1 sector resulting in 120° steps. In order to unravel this symmetry mismatch we monitor subunit rotation by a single-molecule fluorescence resonance energy transfer (FRET) approach using three fluorophores specifically attached to the enzyme: one attached to the F1 motor, another one to the Fo motor, and the third one to a non-rotating subunit. To reduce photophysical artifacts due to spectral fluctuations of the single fluorophores, a duty cycle-optimized alternating three-laser scheme (DCO-ALEX) has been developed. Simultaneous observation of the stepsizes for both motors allows the detection of reversible elastic deformations between the rotor parts of Fo and F1.

  17. Evaluación de la eficiencia energética de vehículos pesados en el ciclo // Evaluation of the heavy duty trucks energy efficiency in the modified drive cycle.

    Directory of Open Access Journals (Sweden)

    Ramón Pérez-Gálvez

    2010-01-01

    Full Text Available ResumenEn este trabajo, se presenta la reformulación de un ciclo teórico que consta de los elementosbásicos de un ciclo de viaje real con condiciones prefijadas de movimiento y operación. En lamodificación se tomaron en cuenta los siguientes elementos: frecuencia de rotación mínima enmovimiento estable; eficiencia de la transmisión variable con la velocidad, la carga y la marchaconectada; un nuevo criterio de frecuencia de rotación del motor para el cambio de marchas; elfrenado con el motor embragado y; nuevas expresiones de cuantificación del consumo decombustible. Obteniéndose nuevos modelos matemáticos para la determinación de los indicadoresdel consumo de combustible de vehículos pesados de transmisión mecánica. Se presenta además,un indicador “Coeficiente de Efectividad del Trabajo del Automóvil” (CETA que describe laeficiencia energética durante el periodo de impulso, expresada a través del grado deaprovechamiento de la energía del automóvil para llevar hasta determinada velocidad la masa de lacarga útil.Palabras claves: ciclo de viaje, consumo de combustible, evaluación vehicular, modelos matemáticos._________________________________________________________________AbstractIn this paper, the new formulation of a theoretical drive cycle is presented. It is integrated by stagesof a real drive cycle with the prefix settings of movement and operation. In the cycle modificationthe following approaches are taken account: minimal rotation frequency in stable movement; thetransmission efficiency is variable with the speed, the weight, and the gear ratio; a new rotationfrequency for gear shifting; a motor braking stage and; a group of new equations for the fuelconsumption. New mathematical models were obtained for the fuel consumption indicators of theheavy duty trucks with manual transmission. Furthermore, the indicator Automobile WorkEffectiveness Coefficient is presented. It describes the energy efficiency in the

  18. Autoclave cycle optimization for high performance composite parts manufacturing

    OpenAIRE

    Nele, L.; Caggiano, A.; Teti, R.

    2016-01-01

    In aeronautical production, autoclave curing of composite parts must be performed according to a specified diagram of temperature and pressure vs time. Part-tool assembly thermal inertia and shape have a large influence on the heating and cooling rate, and therefore on the dwell time within the target temperature range. When simultaneously curing diverse composite parts, the total autoclave cycle time is driven by the part-tool assembly with the lower heating and cooling rates. With the aim t...

  19. High exergetic modified Brayton cycle with thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Yazawa, Kazuaki; Fisher, Timothy S.; Groll, Eckhard A.; Shakouri, Ali

    2017-01-01

    Highlights: • Modified Brayton cycle with thermoelectric generators. • 1 kW power output scale hybrid gas turbine for residential applications. • Low profile TEGs are embedded in combustor/recuperator/heat-exchangers. • Analytical primary energy efficiency achieves more than 40%. - Abstract: A novel concept using thermoelectric direct power generators (TEGs) integrated into a 1 kW scale miniature Brayton cycle is investigated based on an analytical study. The work considers a residential scale application aiming to achieve 40% primary energy efficiency in contrast to the state-of-the-art miniature gas turbine alone, which can only achieve <16%. A topping cycle TEG for a hot gas temperature at 1600–1700 °C is embedded in the combustor scale of a kitchen stove. This TEG converts a fraction of the heat into electricity, while all the remaining thermal energy proceeds to the Brayton cycle. Turbine-inlet gas temperature regulates to 800–1100 °C by optimizing the air mixture. A second TEG is built in the recuperator; hence, the associated temperature is similar to that of a vehicle exhaust. A third TEG is used for waste heat recovery from flue gas, and then the downstream heat flow is used by a combined-heat-power system. By taking advantage of low-profile modules, the TEG embedded heat exchanges can be compact and low-cost at 0.2–0.3 $/W. The figure-of-merit of the thermoelectric materials considers ZT 1.0–1.8. Assuming that all advanced components are utilized, the primary energy efficiency predicts 42% with power output 720 W from the alternator and 325 W from the TEGs out of 0.456 g/s of a pipeline natural gas input.

  20. Predictive digital peak current mode controller for DC-DC converters capable of operating over the full 0-100% duty cycle range

    DEFF Research Database (Denmark)

    Andersen, Karsten Holm; Nymand, Morten

    2017-01-01

    ) and discontinuous conduction mode (DCM) and supports high switching frequencies even with low cost A/D converters. The proposed controller is implemented in a Field Programmable Gate Array (FPGA) to control a 450 W buck converter and the experimental results verify the controller's capability to operate in the full...

  1. Thermodynamic optimisation and analysis of four Kalina cycle layouts for high temperature applications

    International Nuclear Information System (INIS)

    Modi, Anish; Haglind, Fredrik

    2015-01-01

    The Kalina cycle has seen increased interest in the last few years as an efficient alternative to the conventional steam Rankine cycle. However, the available literature gives little information on the algorithms to solve or optimise this inherently complex cycle. This paper presents a detailed approach to solve and optimise a Kalina cycle for high temperature (a turbine inlet temperature of 500 °C) and high pressure (over 100 bar) applications using a computationally efficient solution algorithm. A central receiver solar thermal power plant with direct steam generation was considered as a case study. Four different layouts for the Kalina cycle based on the number and/or placement of the recuperators in the cycle were optimised and compared based on performance parameters such as the cycle efficiency and the cooling water requirement. The cycles were modelled in steady state and optimised with the maximisation of the cycle efficiency as the objective function. It is observed that the different cycle layouts result in different regions for the optimal value of the turbine inlet ammonia mass fraction. Out of the four compared layouts, the most complex layout KC1234 gives the highest efficiency. The cooling water requirement is closely related to the cycle efficiency, i.e., the better the efficiency, the lower is the cooling water requirement. - Highlights: • Detailed methodology for solving and optimising Kalina cycle for high temperature applications. • A central receiver solar thermal power plant with direct steam generation considered as a case study. • Four Kalina cycle layouts based on the placement of recuperators optimised and compared

  2. High-frequency thermal-electrical cycles for pyroelectric energy conversion

    International Nuclear Information System (INIS)

    Bhatia, Bikram; Damodaran, Anoop R.; Cho, Hanna; Martin, Lane W.; King, William P.

    2014-01-01

    We report thermal to electrical energy conversion from a 150 nm thick BaTiO 3 film using pyroelectric cycles at 1 kHz. A microfabricated platform enables temperature and electric field control with temporal resolution near 1 μs. The rapid electric field changes as high as 11 × 10 5  kV/cm-s, and temperature change rates as high as 6 × 10 5  K/s allow exploration of pyroelectric cycles in a previously unexplored operating regime. We investigated the effect of phase difference between electric field and temperature cycles, and electric field and temperature change rates on the electrical energy generated from thermal-electrical cycles based on the pyroelectric Ericsson cycle. Complete thermodynamic cycles are possible up to the highest cycle rates tested here, and the energy density varies significantly with phase shifts between temperature and electric field waveforms. This work could facilitate the design and operation of pyroelectric cycles at high cycle rates, and aid in the design of new pyroelectric systems

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

    International Nuclear Information System (INIS)

    Chang Oh

    2004-01-01

    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 turbomachinery. 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

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

    Directory of Open Access Journals (Sweden)

    Fic Adam

    2015-03-01

    Full Text Available 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.

  5. High cycle fatigue of austenitic stainless steels under random loading

    International Nuclear Information System (INIS)

    Gauthier, J.P.; Petrequin, P.

    1987-08-01

    To investigate reactor components, load control random fatigue tests were performed at 300 0 C and 550 0 C, on specimens from austenitic stainless steels plates in the transverse orientation. Random solicitations are produced on closed loop servo-hydraulic machines by a mini computer which generates random load sequence by the use of reduced Markovian matrix. The method has the advantage of taking into account the mean load for each cycle. The solicitations generated are those of a stationary gaussian process. Fatigue tests have been mainly performed in the endurance region of fatigue curve, with scattering determination using stair case method. Experimental results have been analysed aiming at determining design curves for components calculations, depending on irregularity factor and temperature. Analysis in term of mean square root fatigue limit calculation, shows that random loading gives more damage than constant amplitude loading. Damage calculations following Miner rule have been made using the probability density function for the case where the irregularity factor is nearest to 100 %. The Miner rule is too conservative for our results. A method using design curves including random loading effects with irregularity factor as an indexing parameter is proposed

  6. Preliminary analysis of combined cycle of modular high-temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Baogang, Z.; Xiaoyong, Y.; Jie, W.; Gang, Z.; Qian, S.

    2015-01-01

    Modular high-temperature gas cooled reactor (HTGR) is known as one of the most advanced nuclear reactors because of its inherent safety and high efficiency. The power conversion system of HTGR can be steam turbine based on Rankine cycle or gas turbine based on Brayton cycle respectively. The steam turbine system is mature and the gas turbine system has high efficiency but under development. The Brayton-Rankine combined cycle is an effective way to further promote the efficiency. This paper investigated the performance of combined cycle from the viewpoint of thermodynamics. The effect of non-dimensional parameters on combined cycle’s efficiency, such as temperature ratio, compression ratio, efficiency of compressor, efficiency of turbine, was analyzed. Furthermore, the optimal parameters to achieve highest efficiency was also given by this analysis under engineering constraints. The conclusions could be helpful to the design and development of combined cycle of HTGR. (author)

  7. Strength calculation of NPP equipment and pipelines during operation. Low- and high-cycle corrosion fatigue

    International Nuclear Information System (INIS)

    Filatov, V.M.; Evropin, S.V.

    2004-01-01

    This paper presents empirical equations and design curves for structural steels employed in nuclear power facilities with light water reactors. These equations allow to take into account the effects of cycle asymmetry, water coolant and ductility decrease during operation. The fatigue curves cover the low-cycle and high-cycle regions (up to 10 12 cycles). The equations include the mechanical characteristics of steels under static tension. The coolant effect on steel fatigue is allowed for using a model developed at the Argonne National Laboratory

  8. Extension of the supercritical carbon dioxide Brayton cycle for application to the Very High Temperature Reactor

    International Nuclear Information System (INIS)

    Moisseytsev, A.; Sienicki, J. J.

    2010-01-01

    An investigation has been carried out of the feasibility of applying the supercritical carbon dioxide (S-CO 2 ) Brayton cycle to the Very High Temperature Reactor (VHTR). Direct application of the standard S-CO 2 recompression cycle to the VHTR was found to be challenging because of the mismatch in the inherent temperature drops across the He and CO 2 sides of the reactor heat exchanger resulting in a relatively low cycle efficiency of 45 % compared to 48 % for a direct helium cycle. Two approaches consisting of either a cascaded cycle arrangement with three separate cascaded S-CO 2 cycles or, alternately, operation of a single S-CO 2 cycle with the minimum pressure below the critical pressure and the minimum temperature above the critical temperature have been identified and shown to successfully enable the S-CO 2 Brayton cycle to be adapted to the VHTR such that the benefits of the higher S-CO 2 cycle efficiency can be realized. For both approaches, S-CO 2 cycle efficiencies in excess of 49 % are calculated. (authors)

  9. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  10. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    International Nuclear Information System (INIS)

    Wang, Hong; Lee, Sung-Min; Wang, James L.; Lin, Hua-Tay

    2014-01-01

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 10 8 cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications, such as piezoelectric fuel injectors in heavy-duty diesel engines

  11. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    Science.gov (United States)

    Wang, Hong; Lee, Sung-Min; Wang, James L.; Lin, Hua-Tay

    2014-12-01

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 108 cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications, such as piezoelectric fuel injectors in heavy-duty diesel engines.

  12. Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hong, E-mail: wangh@ornl.gov; Lee, Sung-Min; Wang, James L. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Lin, Hua-Tay [School of Mechanical and Electronic Engineering, Guangdong University of Technology, Guangzhou, 510006 (China)

    2014-12-21

    Testing of large prototype lead zirconate titanate (PZT) stacks presents substantial technical challenges to electronic testing systems, so an alternative approach that uses subunits extracted from prototypes has been pursued. Extracted 10-layer and 20-layer plate specimens were subjected to an electric cycle test under an electric field of 3.0/0.0 kV/mm, 100 Hz to 10{sup 8} cycles. The effects of measurement field level and stack size (number of PZT layers) on the fatigue responses of piezoelectric and dielectric coefficients were observed. On-line monitoring permitted examination of the fatigue response of the PZT stacks. The fatigue rate (based on on-line monitoring) and the fatigue index (based on the conductance spectrum from impedance measurement or small signal measurement) were developed to quantify the fatigue status of the PZT stacks. The controlling fatigue mechanism was analyzed against the fatigue observations. The data presented can serve as input to design optimization of PZT stacks and to operation optimization in critical applications, such as piezoelectric fuel injectors in heavy-duty diesel engines.

  13. Microstructure evolution during high cycle fatigue in Mg–6Zn–1Mn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Daliang [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Zhang, Dingfei, E-mail: zhangdingfei@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Luo, Yuanxin [College of Mechanical Engineering, Chongqing University, Chongqing 400030 (China); Sun, Jing; Xu, Junyao [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Pan, Fusheng [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China)

    2016-03-21

    Microstructure evolution during high cycle fatigue in extruded Mg–6Zn–1Mn alloy was investigated by servo-hydraulic fatigue testing machine with pull–push sinusoidal loading. The results show that in high stress cycles (cyclic stress≥129 MPa) high cycle fatigue tests promote deformation; however, in low stress cycles (cyclic stress≤125 MPa) high cycle fatigue tests make a contribution to room temperature recrystallization in Mg–6Zn–1Mn alloy. The grain refinement increased with increasing cycles. Electron Back-Scattered Diffraction (EBSD) analyses showed that dynamic recrystallization (DRX) has occurred in post-fatigued alloys, accompanied by the presence of a high number density of low-angle grain boundaries (LAGBs). LAGBs generated in the vicinity of initiation grain boundaries and subdivided coarse grains. In the specimens that subjected to higher cycles, the fraction of LAGBs decreased and high-angle grain boundaries (HAGBs) gradually increased. With the cyclic number increasing the texture intensity was significantly weakened. The DRX in post-fatigued specimens was related to Continuous DRX (CDRX) mechanism.

  14. Opportunities for High-Value Bioblendstocks to Enable Advanced Light- and Heavy-Duty Engines: Insights from the Co-Optima Project

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, John T [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-01-25

    Co-Optima research and analysis have identified fuel properties that enable advanced light-duty and heavy-duty engines. There are a large number of blendstocks readily derived from biomass that possess beneficial properties. Key research needs have been identified for performance, technology, economic, and environmental metrics.

  15. Caffeine withdrawal and high-intensity endurance cycling performance.

    Science.gov (United States)

    Irwin, Christopher; Desbrow, Ben; Ellis, Aleisha; O'Keeffe, Brooke; Grant, Gary; Leveritt, Michael

    2011-03-01

    In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine consumers (from coffee and a range of other sources), were recruited for the study. A double-blind placebo-controlled cross-over design was employed, involving four experimental trials. Participants abstained from dietary caffeine sources for 4 days before the trials and ingested capsules (one in the morning and one in the afternoon) containing either placebo or caffeine (1.5 mg · kg(-1) body weight · day(-1)). On day 5, capsules containing placebo or caffeine (3 mg · kg(-1) body weight) were ingested 90 min before completing a time trial, equivalent to one hour of cycling at 75% peak sustainable power output. Hence the study was designed to incorporate placebo-placebo, placebo-caffeine, caffeine-placebo, and caffeine-caffeine conditions. Performance time was significantly improved after acute caffeine ingestion by 1:49 ± 1:41 min (3.0%, P = 0.021) following a withdrawal period (placebo-placebo vs. placebo-caffeine), and by 2:07 ± 1:28 min (3.6%, P = 0.002) following the non-withdrawal period (caffeine-placebo vs. caffeine-caffeine). No significant difference was detected between the two acute caffeine trials (placebo-caffeine vs. caffeine-caffeine). Average heart rate throughout exercise was significantly higher following acute caffeine administration compared with placebo. No differences were observed in ratings of perceived exertion between trials. A 3 mg · kg(-1) dose of caffeine significantly improves exercise performance irrespective of whether a 4-day withdrawal period is imposed on habitual caffeine users.

  16. Dynamic high-cadence cycling improves motor symptoms in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Angela eRidgel

    2015-09-01

    Full Text Available Rationale: Individuals with Parkinson’s disease (PD often have deficits in kinesthesia. There is a need for rehabilitation interventions that improve these kinesthetic deficits. Forced (tandem cycling at a high cadence improves motor function. However, tandem cycling is difficult to implement in a rehabilitation setting. Objective: To construct an instrumented, motored cycle and to examine if high cadence dynamic cycling promotes improvements in motor function. Method: This motored cycle had two different modes: dynamic and static cycling. In dynamic mode, the motor maintained 75-85 rpm. In static mode, the rider determined the pedaling cadence. UPDRS Motor III and Timed Up and Go (TUG were used to assess changes in motor function after three cycling sessions. Results: Individuals in the static group showed a lower cadence but a higher power, torque and heart rate than the dynamic group. UPDRS score showed a significant 13.9% improvement in the dynamic group and only a 0.9% improvement in the static group. There was also a 16.5% improvement in TUG time in the dynamic group but only an 8% improvement in the static group. Conclusion: These findings show that dynamic cycling can improve PD motor function and that activation of proprioceptors with a high cadence but variable pattern may be important for motor improvements in PD.

  17. Due diligence duties for an environmental liability

    International Nuclear Information System (INIS)

    Huebsch, M.

    2000-04-01

    Jurisdiction turned out well to create a basic ruling for due diligence duties. These due diligence duties are high standards for the law of torts (outside of contracts) within the Austrian civil law and represent a liability-extension for the holder of the source of danger. They establish an action for injunction in particular for preventing (further) damages. Therewith due diligence duties get a general sense in the range of a civil law for environmental liability. The responsible holder of a danger zone will therefore influence his way of acting to protect potential victims and the environment. The burden of proof is on the plaintiff (victims) under the Civil Code. Victims have specific sources of danger including high endangering special facilities in their argumentation with the so-called prima-facie-proof or first-appearance-proof. A turning back of the presentation of evidence to the polluter is wrong. The polluter himself has a continuing liability for dangerous activities and his clerks in the case of an extremely high danger of damage. All due diligence duties can be arranged in three areas: in information-, danger-avoidance- and danger-prevention-duties. The determination of range and essence of the duties has to be adjusted to each individual case. The range of the specific danger area is the essential link. The intensity of due diligence duties is increasing with the size of danger in the way of a movable system depending on the protected interest. Due diligence duties have to be kept within reasonable limits with two criterions: necessarity and demand. Proportionality of actions is a third criterion to avoid exaggeration of due diligence duties to obtain an effective protection for victims including the environment. (author)

  18. PCR cycles above routine numbers do not compromise high-throughput DNA barcoding results.

    Science.gov (United States)

    Vierna, J; Doña, J; Vizcaíno, A; Serrano, D; Jovani, R

    2017-10-01

    High-throughput DNA barcoding has become essential in ecology and evolution, but some technical questions still remain. Increasing the number of PCR cycles above the routine 20-30 cycles is a common practice when working with old-type specimens, which provide little amounts of DNA, or when facing annealing issues with the primers. However, increasing the number of cycles can raise the number of artificial mutations due to polymerase errors. In this work, we sequenced 20 COI libraries in the Illumina MiSeq platform. Libraries were prepared with 40, 45, 50, 55, and 60 PCR cycles from four individuals belonging to four species of four genera of cephalopods. We found no relationship between the number of PCR cycles and the number of mutations despite using a nonproofreading polymerase. Moreover, even when using a high number of PCR cycles, the resulting number of mutations was low enough not to be an issue in the context of high-throughput DNA barcoding (but may still remain an issue in DNA metabarcoding due to chimera formation). We conclude that the common practice of increasing the number of PCR cycles should not negatively impact the outcome of a high-throughput DNA barcoding study in terms of the occurrence of point mutations.

  19. Fusion blankets for high-efficiency power cycles

    International Nuclear Information System (INIS)

    Usher, J.L.; Lazareth, O.W.; Fillo, J.A.; Horn, F.L.; Powell, J.R.

    1980-01-01

    The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperatures (500 0 C) of conventional structural materials such as stainless steels. In this project two-zone blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO 2 interior (cooled by argon) utilizing Li 2 O for tritium breeding. In this design, approximately 60% of the fusion energy is deposited in the high-temperature interior. The maximum argon temperature is 2230 0 C leading to an overall efficiency estimate of 55 to 60% for this reference case

  20. Fusion blanket for high-efficiency power cycles

    International Nuclear Information System (INIS)

    Usher, J.L.; Powell, J.R.; Fillo, J.A.; Horn, F.L.; Lazareth, O.W.; Taussig, R.

    1980-01-01

    The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperature (500 0 C) of conventional structural materials such as stainless steels. In this project two-zone blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO 2 interior (cooled by Ar) utilizing Li 2 O for tritium breeding. In this design, approx. 60% of the fusion energy is deposited in the high-temperature interior. The maximum Ar temperature is 2230 0 C leading to an overall efficiency estimate of 55 to 60% for this reference case

  1. Fusion blankets for high-efficiency power cycles

    International Nuclear Information System (INIS)

    Usher, J.L.; Lazareth, O.W.; Fillo, J.A.; Horn, F.L.; Powell, J.R.

    1981-01-01

    The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperatures (500 deg C) of conventional structural materials such as stainless steels. In this project 'two-zone' blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO 2 interior (cooled by argon) utilizing Li 2 O for tritium breeding. In this design, approximately 60% of the fusion energy is deposited in the high-temperature interior. The maximum argon temperature is 2230 deg C leading to an overall efficiency estimate of 55 to 60% for this reference case. (author)

  2. High Cycle Fatigue of Metastable Austenitic Stainless Steels

    OpenAIRE

    Fargas Ribas, Gemma; Zapata Dederle, Ana Cristina; Anglada Gomila, Marcos Juan; Mateo García, Antonio Manuel

    2009-01-01

    Metastable austenitic stainless steels are currently used in applications where severe forming operations are required, such as automotive bodies, due to its excellent ductility. They are also gaining interest for its combination of high strength and formability after forming. The biggest disadvantage is the difficulty to predict the mechanical response, which depends heavily on the amount of martensite formed. The martensitic transformation in metastable stainless steels can b...

  3. Energy Approach-Based Simulation of Structural Materials High-Cycle Fatigue

    Science.gov (United States)

    Balayev, A. F.; Korolev, A. V.; Kochetkov, A. V.; Sklyarova, A. I.; Zakharov, O. V.

    2016-02-01

    The paper describes the mechanism of micro-cracks development in solid structural materials based on the theory of brittle fracture. A probability function of material cracks energy distribution is obtained using a probabilistic approach. The paper states energy conditions for cracks growth at material high-cycle loading. A formula allowing to calculate the amount of energy absorbed during the cracks growth is given. The paper proposes a high- cycle fatigue evaluation criterion allowing to determine the maximum permissible number of solid body loading cycles, at which micro-cracks start growing rapidly up to destruction.

  4. Japanese high school students' usage of mobile phones while cycling.

    Science.gov (United States)

    Ichikawa, Masao; Nakahara, Shinji

    2008-03-01

    To investigate the perception and actual use of mobile phones among Japanese high school students while riding their bicycles, and their experience of bicycle crash/near-crash. A questionnaire survey was carried out at high schools that were, at the time of the survey, commissioned by the National Agency for the Advancement of Sports and Health to conduct school safety research. In the survey, we found that mobile phone use while riding a bicycle was quite common among the students during their commute, but those who have a higher perception of danger in this practice, and those who perceived that this practice is prohibited, were less likely to engage in this practice. Male students and students commuting to school by bicycle only were more likely to have used phones while riding. There was a significant relationship between phone usage while riding a bicycle and the experience of bicycle crash/near-crash, although its causality was not established. Bicycle crash/near-crash experienced while using a phone was less prevalent among the students who had a higher perception of danger in phone usage while riding, students who perceived that this practice is prohibited, and students with a shorter travel time by bicycle during the commute. Since mobile phone use while riding a bicycle potentially increases crash risk among cyclists, student bicycle commuters should be made aware of this risk. Moreover, they should be informed that cyclists' phone usage while riding is prohibited according to the road traffic law.

  5. Status in 1998 of the high flux reactor fuel cycle

    International Nuclear Information System (INIS)

    Guidez, J.; Gevers, A.; Wijtsma, F.J.; Thijssen, P.M.J.

    1998-01-01

    The High Flux Reactor located at Petten (The Netherlands), is owned by the European Commission and is operated under contract by ECN (Netherlands Energy Research Foundation). This plant is in operation since 1962 using HEU enriched at 90%. Conversion studies were conducted several years ago with the hypothesis of a global conversion of the entire core. The results of these studies have shown a costly operation with a dramatic decrease of the thermal flux which is necessary for the medical use of the plant (Molybdene 99 production). Some tests with low enriched elements were also conducted with several companies, several geometrical configurations and several enrichments. They are described in this paper. Explanations are also given on future possibilities for new fuel testing. (author)

  6. Solvent extraction process development for high plutonium fuel cycles

    Energy Technology Data Exchange (ETDEWEB)

    Anil Kumar, R; Selvaraj, P G; Natarajan, R; Raman, V R [Reprocessing Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1994-06-01

    The purification of high plutonium bearing irradiated fuels using 30% TBP in dodecane diluent requires precise determination of concentration profiles during steady state, transient and process upset conditions. Mathematical models have been developed and a computer code is in use for determining Pu-U concentration profiles in a solvent extraction equipment in a typical reprocessing plant. The process parameters have been optimised for recovery of U and Pu and decontamination from the fission products. This computer code is used to analyse the extraction flow sheets of fuels of two typical Pu-U compositions encountered in Indian fast breeder programme. The analysis include the effect of uncertainty in equilibrium condition prediction by the model and the variation of flows of streams during plant operation. The studies highlight the margin available to avoid second organic phase formation and adjustments required in the process flowsheet. (author). 7 refs., 7 figs., 2 tabs.

  7. Thermodynamic analysis of high-temperature regenerative organic Rankine cycles using siloxanes as working fluids

    International Nuclear Information System (INIS)

    Fernandez, F.J.; Prieto, M.M.; Suarez, I.

    2011-01-01

    A recent novel adjustment of the Span-Wagner equation of state for siloxanes, used as working fluids in high-temperature organic Rankine cycles, is applied in a mathematical model to solve cycles under several working conditions. The proposed scheme includes a thermo-oil intermediate heat circuit between the heat source and the organic Rankine cycle. Linear and cyclic siloxanes are assayed in saturated, superheated and supercritical cycles. The cycle includes an internal heat exchanger (regenerative cycle), although a non-regenerative scheme is also solved. In the first part of the study, a current of combustion gases cooled to close to their dew point temperature is taken as the reference heat source. In the second part, the outlet temperature of the heat source is varied over a wide range, determining appropriate fluids and schemes for each thermal level. Simple linear (MM, MDM) siloxanes in saturated regenerative schemes show good efficiencies and ensure thermal stability of the working fluid. -- Highlights: → Organic Rankine cycles with polymethylsiloxanes as working fluids were modelled. → The cycle scheme is regenerative and includes an intermediate heat transfer fluid. → The fluid properties were calculated by means of the Span-Wagner equation of state. → Vapour conditions to the expander and source thermal level were analysed. → Siloxanes MM, MDM and D 4 under saturated conditions were the best options.

  8. Fuel cycle performance indices in a high-converting LWR core design with once-through thorium fuel cycle

    International Nuclear Information System (INIS)

    Kim, Myung-Hyun; Kim, Kwan-Hee; Kim, Young-il

    2004-01-01

    A design concept of pressure-tube type light water cooled reactor (HCPLWR) core was proposed as a thermal high-conversion reactor using a thorium based once-through cycle strategy. In a previous work, fuel cycle economics and nuclear safety were confirmed. In this work, HCPLWR was evaluated in the aspects of proliferation resistance and transmutation capability. Evaluation was done as a direct comparison of indices with PWR, CANDU and Radkowsky Thorium Fuel (RTF). Conversion ratio was measured by fissile inventory ratio and fissile gain. Proliferation resistance of plutonium composition from spent seed and blanket fuels was measured by bare critical mass, spontaneous neutron source rate, and thermal heat generation rate. For the evaluation of long-lived minor actinide transmutation was measured by a new parameter, effective fission half-life. Two-dimensional calculation for the assembly-wise unit module showed each parameter values. Even though conversion capability of HCPLWR was higher than one of RTF, it was concluded that current HCPLWR design was not favorable than RTF. Design optimization is required for the future work. (author)

  9. Nuclear fuel cycle system simulation tool based on high-fidelity component modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ames, David E.,

    2014-02-01

    The DOE is currently directing extensive research into developing fuel cycle technologies that will enable the safe, secure, economic, and sustainable expansion of nuclear energy. The task is formidable considering the numerous fuel cycle options, the large dynamic systems that each represent, and the necessity to accurately predict their behavior. The path to successfully develop and implement an advanced fuel cycle is highly dependent on the modeling capabilities and simulation tools available for performing useful relevant analysis to assist stakeholders in decision making. Therefore a high-fidelity fuel cycle simulation tool that performs system analysis, including uncertainty quantification and optimization was developed. The resulting simulator also includes the capability to calculate environmental impact measures for individual components and the system. An integrated system method and analysis approach that provides consistent and comprehensive evaluations of advanced fuel cycles was developed. A general approach was utilized allowing for the system to be modified in order to provide analysis for other systems with similar attributes. By utilizing this approach, the framework for simulating many different fuel cycle options is provided. Two example fuel cycle configurations were developed to take advantage of used fuel recycling and transmutation capabilities in waste management scenarios leading to minimized waste inventories.

  10. A Combined High and Low Cycle Fatigue Model for Life Prediction of Turbine Blades

    Directory of Open Access Journals (Sweden)

    Shun-Peng Zhu

    2017-06-01

    Full Text Available Combined high and low cycle fatigue (CCF generally induces the failure of aircraft gas turbine attachments. Based on the aero-engine load spectrum, accurate assessment of fatigue damage due to the interaction of high cycle fatigue (HCF resulting from high frequency vibrations and low cycle fatigue (LCF from ground-air-ground engine cycles is of critical importance for ensuring structural integrity of engine components, like turbine blades. In this paper, the influence of combined damage accumulation on the expected CCF life are investigated for turbine blades. The CCF behavior of a turbine blade is usually studied by testing with four load-controlled parameters, including high cycle stress amplitude and frequency, and low cycle stress amplitude and frequency. According to this, a new damage accumulation model is proposed based on Miner’s rule to consider the coupled damage due to HCF-LCF interaction by introducing the four load parameters. Five experimental datasets of turbine blade alloys and turbine blades were introduced for model validation and comparison between the proposed Miner, Manson-Halford, and Trufyakov-Kovalchuk models. Results show that the proposed model provides more accurate predictions than others with lower mean and standard deviation values of model prediction errors.

  11. High-duty pistons and sliding bearings for internal combustion engines. Hochbelastbare Kolben und Gleitlager fuer Verbrennungsmotoren: Spuerbare Leistungssteigerung

    Energy Technology Data Exchange (ETDEWEB)

    Pfestorf, H. (Kolbenschmidt AG, Neckarsulm (Germany, F.R.))

    Rising demands on high-performance engines, particularly on their connecting rod bearings, call for advanced materials, mainly concerning better resistance to fatigue and corrosion at high temperatures and reduced wear rate in zones of intensive friction. Material suppliers will have to take these demands into account by launching new innovative grades or material combinations. (orig.).

  12. A method for calculation of finite fatigue life under multiaxial loading in high-cycle domain

    Directory of Open Access Journals (Sweden)

    M. Malnati

    2014-04-01

    Full Text Available A method for fatigue life assessment in high-cycle domain under multiaxial loading is presented in this paper. This approach allows fatigue assessment under any kind of load history, without limitations. The methodology lies on the construction - at a macroscopic level - of an “indicator” in the form of a set of cycles, representing plasticity that can arise at mesoscopic level throughout fatigue process. During the advancement of the loading history new cycles are created and a continuous evaluation of the damage is made.

  13. High temperature high velocity direct power extraction using an open-cycle oxy-combustion system

    Energy Technology Data Exchange (ETDEWEB)

    Love, Norman [Univ. of Texas, El Paso, TX (United States)

    2017-09-29

    The implementation of oxy-fuel technology in fossil-fuel power plants may contribute to increased system efficiencies and a reduction of pollutant emissions. One technology that has potential to utilize the temperature of undiluted oxy-combustion flames is open-cycle magnetohydrodynamic (MHD) power generators. These systems can be configured as a topping cycle and provide high enthalpy, electrically conductive flows for direct conversion of electricity. This report presents the design and modeling strategies of a MHD combustor operating at temperatures exceeding 3000 K. Throughout the study, computational fluid dynamics (CFD) models were extensively used as a design and optimization tool. A lab-scale 60 kWth model was designed, manufactured and tested as part of this project. A fully-coupled numerical method was developed in ANSYS FLUENT to characterize the heat transfer in the system. This study revealed that nozzle heat transfer may be predicted through a 40% reduction of the semi-empirical Bartz correlation. Experimental results showed good agreement with the numerical evaluation, with the combustor exhibiting a favorable performance when tested during extended time periods. A transient numerical method was employed to analyze fuel injector geometries for the 60-kW combustor. The ANSYS FLUENT study revealed that counter-swirl inlets achieve a uniform pressure and velocity ratio when the ports of the injector length to diameter ratio (L/D) is 4. An angle of 115 degrees was found to increase distribution efficiency. The findings show that this oxy-combustion concept is capable of providing a high-enthalpy environment for seeding, in order to render the flow to be conductive. Based on previous findings, temperatures in the range of 2800-3000 K may enable magnetohydrodynamic power extraction. The heat loss fraction in this oxy-combustion system, based on CFD and analytical calculations, at optimal operating conditions, was estimated to be less than 10 percent

  14. Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

    OpenAIRE

    Setiadipura, T; Irwanto, D; Zuhair, Zuhair

    2015-01-01

    The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor ...

  15. Combustion and emissions characteristics of high n-butanol/diesel ratio blend in a heavy-duty diesel engine and EGR impact

    International Nuclear Information System (INIS)

    Chen, Zheng; Wu, Zhenkuo; Liu, Jingping; Lee, Chiafon

    2014-01-01

    Highlights: • Effects of EGR on high n-butanol/diesel ratio blend (Bu40) were investigated and compared with neat diesel (Bu00). • Bu40 has higher NOx due to wider combustion high-temperature region. • Bu40 has lower soot due to local lower equivalence ratio distribution. • Bu40 has higher CO due to lower gas temperature in the late expansion process. • For Bu40, EGR reduces NOx emissions dramatically with no obvious influence on soot. - Abstract: In this work, the combustion and emission fundamentals of high n-butanol/diesel ratio blend with 40% butanol (i.e., Bu40) in a heavy-duty diesel engine were investigated by experiment and simulation at constant engine speed of 1400 rpm and an IMEP of 1.0 MPa. Additionally, the impact of EGR was evaluated experimentally and compared with neat diesel fuel (i.e., Bu00). The results show that Bu40 has higher cylinder pressure, longer ignition delay, and faster burning rate than Bu00. Compared with Bu00, moreover, Bu40 has higher NOx due to wider combustion high-temperature region, lower soot due to local lower equivalence ratio distribution, and higher CO due to lower gas temperature in the late expansion process. For Bu40, EGR reduces NOx emissions dramatically with no obvious influence on soot. Meanwhile, there is no significant change in HC and CO emissions and indicated thermal efficiency (ITE) with EGR until EGR threshold is reached. When EGR rate exceeds the threshold level, HC and CO emissions increase dramatically, and ITE decreases markedly. Compared with Bu00, the threshold of Bu40 appears at lower EGR rate. Consequently, combining high butanol/diesel ratio blend with medium EGR has the potential to achieve ultra-low NOx and soot emissions simultaneously while maintaining high thermal efficiency level

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

    International Nuclear Information System (INIS)

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

    2006-01-01

    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

  17. High-potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Zia, Jalal [GE Global Research; Sevincer, Edip; Chen, Huijuan; Hardy, Ajilli; Wickersham, Paul; Kalra, Chiranjeev; Laursen, Anna Lis; Vandeputte, Thomas

    2013-06-29

    hours of exposure?only 3% of the initial charge degraded into by products. The main degradation products being an isomer and a dimer. 3. In a comparative experiment between R245fa and the new fluid under subcritical conditions, it was found that the new fluid operated at 1 bar lower than R245fa for the same power output, which was also predicted in the Aspen HSYSY model. As a drop-in replacement fluid for R245fa, this new fluid was found to be at least as good as R245fa in terms of performance and stability. Further optimization of the subcritical cycle may lead to a significant improvement in performance for the new fluid. 4. For supercritical conditions, the experiment found a good match between the measured and model predicted state point property data and duties from the energy balance. The largest percent differences occurred with densities and evaporator duty (see Figure 78). It is therefore reasonable to conclude that the state point model was experimentally validated with a realistic ORC system. 5. The team also undertook a preliminary turbo-expander design study for a supercritical ORC cycle with the new working fluid. Variants of radial and axial turbo expander geometries went through preliminary design and rough costing. It was found that at 15MWe or higher power rating, a multi-stage axial turbine is most suitable providing the best performance and cost. However, at lower power ratings in the 5MWe range, the expander technology to be chosen depends on the application of the power block. For EGS power blocks, it is most optimal to use multi-stage axial machines. In conclusion, the predictions of the LCOE model that showed a supercritical cycle based on the new fluid to be most advantageous for geothermal power production at a resource temperature of ~ 200C have been experimentally validated. It was found that the cycle based on the new fluid is lower in LCOE and higher in net power output (for the same boundary conditions). The project, therefore has found a

  18. Evaluation of Exercise Response in a Young, High Risk Population: Submaximal Invasive Cardiopulmonary Exercise Testing (ICPET) in Active Duty Soldiers

    Science.gov (United States)

    2017-03-17

    funding source for your study [e.g., S9 MOW CRD Graduate Health Sciences Educa tion (GHSE) (SGS O&M); SGS R&D; Tri-Service Nursing Research Program (TSNRP...Fidelity Hemodynamic Waveform and Data Repository for Training A llied Health Personnel and Research 6. TITLE OF MATERIAL TO BE PUBLISHED OR PRESENTED...Ph.D. February 11 , 2015 FROM: PROJECT TITLE: Brooke Army Medical Center (BAMC) Institutional Review Board (408191-1] High-Fidelity Hemodynamic

  19. Technical Issues in the development of high burnup and long cycle fuel pellets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Joo; Yang, Jae Ho; Oh, Jang Soo; Kim, Keon Sik; Rhee, Young Woo; Kim, Jong Hun; Nam, Ik Hui [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-10-15

    Over the last half century, a nuclear fuel cycle, a fuel discharged burnup and a uranium enrichment of the LWR (Light Water Reactor) fuel have continuously increased. It was the efforts to reduce the LWR fuel cycle cost, and to make reactor operation more efficiently. Improved fuel and reactor performance contribute further to the reduction and management efficiency of spent fuels. The primary incentive for operating nuclear reactor fuel to higher burnup and longer cycle is the economic benefits. The fuel cycle costs could be reduced by extending fuel discharged burnup and fuel cycle length. The higher discharged burnup can increase the energy production per unit fuel mass or fuel assembly. The longer fuel cycle can increase reactor operation flexibility and reduce the fuel changing operation and the spent fuel management burden. The margin to storage capacity limits would be also increased because high burnup and long cycle fuel reduces the mass of spent fuels. However, increment of fuel burnup and cycle length might result in the acceleration of material aging consisting fuel assembly. Then, the safety and integrity of nuclear fuel will be degraded. Therefore, to simultaneously enhance the safety and economics of the LWR fuel through the fuel burnup and cycle extension, it is indispensable to develop the innovative nuclear fuel material concepts and technologies which can overcome degradation of fuel safety. New fuel research project to extend fuel discharged burnup and cycle length has been launched in KAERI. Main subject is to develop innovative LWR fuel pellets which can provide required fuel performance and safety at extended fuel burnup and cycle length. In order to achieve the mission, we need to know that what the impediments are and how to break through current limit of fuel pellet properties. In this study, the technical issues related to fuel pellets at high burnup were surveyed and summarized. We have collected the technical issues in the literatures

  20. Technical Issues in the development of high burnup and long cycle fuel pellets

    International Nuclear Information System (INIS)

    Kim, Dong Joo; Yang, Jae Ho; Oh, Jang Soo; Kim, Keon Sik; Rhee, Young Woo; Kim, Jong Hun; Nam, Ik Hui

    2012-01-01

    Over the last half century, a nuclear fuel cycle, a fuel discharged burnup and a uranium enrichment of the LWR (Light Water Reactor) fuel have continuously increased. It was the efforts to reduce the LWR fuel cycle cost, and to make reactor operation more efficiently. Improved fuel and reactor performance contribute further to the reduction and management efficiency of spent fuels. The primary incentive for operating nuclear reactor fuel to higher burnup and longer cycle is the economic benefits. The fuel cycle costs could be reduced by extending fuel discharged burnup and fuel cycle length. The higher discharged burnup can increase the energy production per unit fuel mass or fuel assembly. The longer fuel cycle can increase reactor operation flexibility and reduce the fuel changing operation and the spent fuel management burden. The margin to storage capacity limits would be also increased because high burnup and long cycle fuel reduces the mass of spent fuels. However, increment of fuel burnup and cycle length might result in the acceleration of material aging consisting fuel assembly. Then, the safety and integrity of nuclear fuel will be degraded. Therefore, to simultaneously enhance the safety and economics of the LWR fuel through the fuel burnup and cycle extension, it is indispensable to develop the innovative nuclear fuel material concepts and technologies which can overcome degradation of fuel safety. New fuel research project to extend fuel discharged burnup and cycle length has been launched in KAERI. Main subject is to develop innovative LWR fuel pellets which can provide required fuel performance and safety at extended fuel burnup and cycle length. In order to achieve the mission, we need to know that what the impediments are and how to break through current limit of fuel pellet properties. In this study, the technical issues related to fuel pellets at high burnup were surveyed and summarized. We have collected the technical issues in the literatures

  1. High-temperature gas-cooled reactor steam cycle/cogeneration application study update

    International Nuclear Information System (INIS)

    1981-09-01

    Since publication of a report on the application of a High Temperature Gas-Cooled Reactor Steam Cycle/Cogeneration (HTGR-SC/C) plant in December of 1980, progress has continued on application related activities. In particular, a reference plant and an application identification effort has been performed, a variable cogeneration cycle balance-of-plant design was developed and an updated economic analysis was prepared. A reference HTGR-SC/C plant size of 2240 MW(t) was selected, primarily on the basis of 2240 MW(t) being in the mid-range of anticipated application needs and the availability of the design data from the 2240 MW(t) Steam Cycle/Electric generation plant design. A variable cogeneration cycle plant design was developed having the capability of operating at a range of process steam loads between the reference design load (full cogeneration) and the no process steam load condition

  2. Performance assessment modeling of high level nuclear wasteforms from the pyroprocess fuel cycle

    International Nuclear Information System (INIS)

    Nutt, W.M.; Hill, R.N.; Bullen, D.B.

    1995-01-01

    Several performance assessment (PA) analyses have been completed to estimate the release to the accessible environment of radionuclides from spent light water reactor (LWR) fuel emplaced in the proposed Yucca Mountain repository. Probabilistic methods were utilized based on the complexity of the repository system. Recent investigations have been conducted to identify the merits of a pyroprocess fuel cycle. This cycle utilizes high temperature molten salts and metals to partially separate actinides and fission products. In a closed liquid metal reactor (LMR) fuel cycle, this allows recycling of nearly all of the actinides. In a once-through cycle, this isolates the actinides for storage into a wasteform which can be specifically tailored for their retention. With appropriate front-end treatment, this Process can also be used to treat LWR spent fuel

  3. INFORMATION MODELING OF LIFE CYCLE OF HIGH-RISE CONSTRUCTION PROJECTS

    Directory of Open Access Journals (Sweden)

    Gusakova Elena Aleksandrovna

    2018-02-01

    Full Text Available To date, many years’ experience in the construction and operation of high-rise buildings has been accumulated. Its analysis reveals not only the engineering and organizational-technological specifics of such projects, but also systemic gaps in the field of management. In the implementation of large-scale and unique projects for high-rise buildings, the problems and tasks of improving approaches to managing the full life cycle of projects and methods, which will improve their competitiveness, become topical. The systems being used have largely exhausted their resource efficiency, which is associated with automation of traditional “inherited” processes and management structures, as well as development of IT-systems focused on digitalization of the activities of construction company, rather than the project. To solve these problems, it is proposed to carry out: reengineering of the schemes of information interaction between the project’s participants; formation of integrated digital environment for the life cycle of the project; development of systems for integrating data management and project management. Subject: problems, approaches and methods of digitalization of project’s life cycle management in relation to the specifics and features of high-rise buildings. Research objectives: substantiation of the most perspective approaches and methods of information modeling of high-rise construction as the basis for managing the full life cycle of the given project. Materials and methods: the experience of digitalization of design, construction, operation and development of high-rise buildings, presented in specialized literature, is analyzed. The methods for integrating information models of various stages of project’s life cycle and for information interaction of project’s participants are considered. Results: the concept of forming a single digital environment for the project is proposed, taking into account the features of the life

  4. Development of high-rise buildings: digitalization of life cycle management

    Directory of Open Access Journals (Sweden)

    Gusakova Elena

    2018-01-01

    Full Text Available The analysis of the accumulated long-term experience in the construction and operation of high-rise buildings reveals not only the engineering specificity of such projects, but also systemic problems in the field of project management. Most of the project decisions are made by the developer and the investor in the early stages of the life cycle - from the acquisition of the site to the start of operation, so most of the participants in the construction and operation of the high-rise building are far from the strategic life-cycle management of the project. The solution of these tasks due to the informatization of management has largely exhausted its efficiency resource. This is due to the fact that the applied IT-systems automated traditional "inherited" processes and management structures, and, in addition, they were focused on informatization of the activities of the construction company, rather than the construction project. Therefore, in the development of high-rise buildings, the tasks of researching approaches and methods for managing the full life cycle of projects that will improve their competitiveness become topical. For this purpose, the article substantiates the most promising approaches and methods of informational modeling of high-rise construction as a basis for managing the full life cycle of this project. Reengineering of information interaction schemes for project participants is considered; formation of a unified digital environment for the life cycle of the project; the development of systems for integrating data management and project management.

  5. Development of high-rise buildings: digitalization of life cycle management

    Science.gov (United States)

    Gusakova, Elena

    2018-03-01

    The analysis of the accumulated long-term experience in the construction and operation of high-rise buildings reveals not only the engineering specificity of such projects, but also systemic problems in the field of project management. Most of the project decisions are made by the developer and the investor in the early stages of the life cycle - from the acquisition of the site to the start of operation, so most of the participants in the construction and operation of the high-rise building are far from the strategic life-cycle management of the project. The solution of these tasks due to the informatization of management has largely exhausted its efficiency resource. This is due to the fact that the applied IT-systems automated traditional "inherited" processes and management structures, and, in addition, they were focused on informatization of the activities of the construction company, rather than the construction project. Therefore, in the development of high-rise buildings, the tasks of researching approaches and methods for managing the full life cycle of projects that will improve their competitiveness become topical. For this purpose, the article substantiates the most promising approaches and methods of informational modeling of high-rise construction as a basis for managing the full life cycle of this project. Reengineering of information interaction schemes for project participants is considered; formation of a unified digital environment for the life cycle of the project; the development of systems for integrating data management and project management.

  6. Development of a high cycle vibration fatigue diagnostic system with non-contact vibration sensing

    International Nuclear Information System (INIS)

    Yoshitsugu, Nekomoto; Satoshi, Kiriyama; Moritatsu, Nishimura; Kenji, Matsumoto; Eiji, O'shima

    2001-01-01

    Nuclear power plants have a large number of pipes. Of these small-diameter pipe branches in particular are often damaged due to high-cycle fatigue. In order to ensure the reliability of a plant it is important to detect the fatigues in pipe branches at an early stage and to develop the technology to predict and diagnose the advancement of fatigue. Further, in order to carry out the diagnosis of the piping system effectively during operation, non-contact evaluation is useful. Hence, we have developed a 'high-cycle fatigue diagnostic system with non-contact vibration sensing', where the vibration of the pipe branch is measured using a non-contact sensor. Since the contents of the developed sensor technology has already been reported, this paper mainly describes the newly developed high-cycle fatigue diagnostic system. (authors)

  7. High-Cycle, Push–Pull Fatigue Fracture Behavior of High-C, Si–Al-Rich Nanostructured Bainite Steel

    Science.gov (United States)

    Zhao, Jing; Ji, Honghong

    2017-01-01

    The high-cycle, push–pull fatigue fracture behavior of high-C, Si–Al-rich nanostructured bainitic steel was studied through the measurement of fatigue limits, a morphology examination and phase composition analysis of the fatigue fracture surface, as well as fractography of the fatigue crack propagation. The results demonstrated that the push–pull fatigue limits at 107 cycles were estimated as 710–889 MPa, for the samples isothermally transformed at the temperature range of 220–260 °C through data extrapolation, measured under the maximum cycle number of 105. Both the interior inclusion and the sample surface constituted the fatigue crack origins. During the fatigue crack propagation, a high amount of secondary cracks were formed in almost parallel arrangements. The apparent plastic deformation occurred in the fracture surface layer, which induced approximately all retained austenite to transform into martensite. PMID:29286325

  8. High-Cycle, Push–Pull Fatigue Fracture Behavior of High-C, Si–Al-Rich Nanostructured Bainite Steel

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2017-12-01

    Full Text Available The high-cycle, push–pull fatigue fracture behavior of high-C, Si–Al-rich nanostructured bainitic steel was studied through the measurement of fatigue limits, a morphology examination and phase composition analysis of the fatigue fracture surface, as well as fractography of the fatigue crack propagation. The results demonstrated that the push–pull fatigue limits at 107 cycles were estimated as 710–889 MPa, for the samples isothermally transformed at the temperature range of 220–260 °C through data extrapolation, measured under the maximum cycle number of 105. Both the interior inclusion and the sample surface constituted the fatigue crack origins. During the fatigue crack propagation, a high amount of secondary cracks were formed in almost parallel arrangements. The apparent plastic deformation occurred in the fracture surface layer, which induced approximately all retained austenite to transform into martensite.

  9. Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

    Directory of Open Access Journals (Sweden)

    L.P. Rodriguez

    2015-08-01

    Full Text Available Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR and two Pebble-Bed Accelerator Driven Systems (ADSs was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.

  10. Highly purified HMG versus recombinant FSH for ovarian stimulation in IVF cycles

    DEFF Research Database (Denmark)

    Platteau, P.; Nyboe, Andersen A.; Loft, A.

    2008-01-01

    The objective of this study was to compare the live birth rates resulting from ovarian stimulation with highly purified human menopausal gonadotrophin (HP-HMG), which combines FSH and human chorionic gonadotrophin-driven LH activities, or recombinant FSH (rFSH) alone in women undergoing IVF cycles....... An integrated analysis was performed of the raw data from two randomized controlled trials that were highly comparable in terms of eligibility criteria and post-randomization treatment regimens with either HP-HMG or rFSH for ovarian stimulation in IVF, following a long down-regulation protocol. All randomized...... subjects who received at least one dose of gonadotrophin in an IVF cycle (HP-HMG, n = 491; rFSH, n = 495) were included in the analysis. Subjects who underwent intracytoplasmic sperm injection cycles were excluded. The superiority of one gonadotrophin preparation over the other was tested using...

  11. Prediction of three-dimensional crack propagation paths taking high cycle fatigue into account

    Directory of Open Access Journals (Sweden)

    Guido Dhondt

    2016-01-01

    Full Text Available Engine components are usually subject to complex loading patterns such as mixed-mode Low Cycle Fatigue Loading due to maneuvering. In practice, this LCF Loading has to be superimposed by High Cyclic Fatigue Loading caused by vibrations. The changes brought along by HCF are twofold: first, the vibrational cycles which are superposed on the LCF mission increase the maximum loading of the mission and may alter the principal stress planes. Secondly, the HCF cycles themselves have to be evaluated on their own, assuring that no crack propagation occurs. Indeed, the vibrational frequency is usually so high that propagation leads to immediate failure. In the present paper it is explained how these two effects can be taken care of in a standard LCF crack propagation procedure. The method is illustrated by applying the Finite Element based crack propagation software CRACKTRACER3D on an engine blade.

  12. New load cycling strategy for enhanced durability of high temperature proton exchange membrane fuel cell

    DEFF Research Database (Denmark)

    Thomas, Sobi; Jeppesen, Christian; Steenberg, Thomas

    2017-01-01

    The objective of this paper is to develop a new operational strategy to increase the lifetime of a high temperature proton exchange membrane (HT-PEMFCs) fuel cell system by using load cycling patterns to reduce the phosphoric acid loss from the fuel cell. Four single cells were operated under.......8 Acm-2 for the higher end, were selected for the load cycling operation. The relaxation time, which is the period of time spent at low current density operation, is varied to understand how the performance over prolonged period behaves. The duration of the high current density operation is selected...... based on the relaxation time in order to have the same average current density of (0.55 Acm-2 ) for all the cells. Cell 5, with a relaxation time of 2 min performs best and shows lower degradation rate of 36 μVh-1 compared to other load cycling cells with smaller relaxation times. The cell operated...

  13. Performance Analysis of a Reciprocating Piston Expander and a Plate Type Exhaust Gas Recirculation Boiler in a Water-Based Rankine Cycle for Heat Recovery from a Heavy Duty Diesel Engine

    Directory of Open Access Journals (Sweden)

    Gunnar Latz

    2016-06-01

    Full Text Available The exhaust gas in an internal combustion engine provides favorable conditions for a waste-heat recovery (WHR system. The highest potential is achieved by the Rankine cycle as a heat recovery technology. There are only few experimental studies that investigate full-scale systems using water-based working fluids and their effects on the performance and operation of a Rankine cycle heat recovery system. This paper discusses experimental results and practical challenges with a WHR system when utilizing heat from the exhaust gas recirculation system of a truck engine. The results showed that the boiler’s pinch point necessitated trade-offs between maintaining adequate boiling pressure while achieving acceptable cooling of the EGR and superheating of the water. The expander used in the system had a geometric compression ratio of 21 together with a steam outlet timing that caused high re-compression. Inlet pressures of up to 30 bar were therefore required for a stable expander power output. Such high pressures increased the pump power, and reduced the EGR cooling in the boiler because of pinch-point effects. Simulations indicated that reducing the expander’s compression ratio from 21 to 13 would allow 30% lower steam supply pressures without adversely affecting the expander’s power output.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

    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

  15. Determining your duties.

    Science.gov (United States)

    Summers, J

    1989-04-01

    This issue's discussion has two goals. First, we shall examine the reasons clinical personnel gravitate to the Kantian concept of duty. Second, we shall examine a technique used within Kantian theory that will help you decide when an ethical dilemma obligates you to act regardless of the consequences.

  16. The Duty to Recognize Culture

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2012-01-01

    On Taylor and Honneth's theories of recognition and whether one can derive a "duty to recognize Culture" from these......On Taylor and Honneth's theories of recognition and whether one can derive a "duty to recognize Culture" from these...

  17. High-temperature nuclear reactor power plant cycle for hydrogen and electricity production – numerical analysis

    Directory of Open Access Journals (Sweden)

    Dudek Michał

    2016-01-01

    Full Text Available High temperature gas-cooled nuclear reactor (called HTR or HTGR for both electricity generation and hydrogen production is analysed. The HTR reactor because of the relatively high temperature of coolant could be combined with a steam or gas turbine, as well as with the system for heat delivery for high-temperature hydrogen production. However, the current development of HTR’s allows us to consider achievable working temperature up to 750°C. Due to this fact, industrial-scale hydrogen production using copper-chlorine (Cu-Cl thermochemical cycle is considered and compared with high-temperature electrolysis. Presented calculations show and confirm the potential of HTR’s as a future solution for hydrogen production without CO2 emission. Furthermore, integration of a hightemperature nuclear reactor with a combined cycle for electricity and hydrogen production may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

  18. A multi-scale approach for high cycle anisotropic fatigue resistance: Application to forged components

    International Nuclear Information System (INIS)

    Milesi, M.; Chastel, Y.; Hachem, E.; Bernacki, M.; Loge, R.E.; Bouchard, P.O.

    2010-01-01

    Forged components exhibit good mechanical strength, particularly in terms of high cycle fatigue properties. This is due to the specific microstructure resulting from large plastic deformation as in a forging process. The goal of this study is to account for critical phenomena such as the anisotropy of the fatigue resistance in order to perform high cycle fatigue simulations on industrial forged components. Standard high cycle fatigue criteria usually give good results for isotropic behaviors but are not suitable for components with anisotropic features. The aim is to represent explicitly this anisotropy at a lower scale compared to the process scale and determined local coefficients needed to simulate a real case. We developed a multi-scale approach by considering the statistical morphology and mechanical characteristics of the microstructure to represent explicitly each element. From stochastic experimental data, realistic microstructures were reconstructed in order to perform high cycle fatigue simulations on it with different orientations. The meshing was improved by a local refinement of each interface and simulations were performed on each representative elementary volume. The local mechanical anisotropy is taken into account through the distribution of particles. Fatigue parameters identified at the microscale can then be used at the macroscale on the forged component. The linkage of these data and the process scale is the fiber vector and the deformation state, used to calculate global mechanical anisotropy. Numerical results reveal an expected behavior compared to experimental tendencies. We proved numerically the dependence of the anisotropy direction and the deformation state on the endurance limit evolution.

  19. Fatigue behaviour and failure analysis of IN 713LC in high-cycle fatigue region

    Czech Academy of Sciences Publication Activity Database

    Mintách, R.; Kunz, Ludvík; Bokůvka, O.

    2009-01-01

    Roč. 16, 3a (2009), s. 37-40 ISSN 1335-0803 R&D Projects: GA MPO FT-TA4/023 Institutional research plan: CEZ:AV0Z20410507 Keywords : Ni base superalloy * casting defect * high-cycle fatigue Subject RIV: JG - Metallurgy

  20. Effects of high-intensity interval cycling performed after resistance training on muscle strength and hypertrophy.

    Science.gov (United States)

    Tsitkanou, S; Spengos, K; Stasinaki, A-N; Zaras, N; Bogdanis, G; Papadimas, G; Terzis, G

    2017-11-01

    Aim of the study was to investigate whether high-intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty-two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high-intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross-sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P high-intensity interval cycling performed after heavy-resistance exercise may not inhibit resistance exercise-induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high-intensity cycling after heavy-resistance exercise may decrease RFD partly due to muscle architectural changes. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen

    Science.gov (United States)

    Appleby, A. J.; Dhar, H. P.; Kim, Y. J.; Murphy, O. J.

    1989-01-01

    The nickel-hydrogen secondary battery system, developed in the early 1970s, has become the system of choice for geostationary earth orbit (GEO) applications. However, for low earth orbit (LEO) satellites with long expected lifetimes the nickel positive limits performance. This requires derating of the cell to achieve very long cycle life. A new system, rechargeable MnO2-Hydrogen, which does not require derating, is described here. For LEO applications, it promises to have longer cycle life, high rate capability, a higher effective energy density, and much lower self-discharge behavior than those of the nickel-hydrogen system.

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

    Science.gov (United States)

    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.

  3. Driving and engine cycles

    CERN Document Server

    Giakoumis, Evangelos G

    2017-01-01

    This book presents in detail the most important driving and engine cycles used for the certification and testing of new vehicles and engines around the world. It covers chassis and engine-dynamometer cycles for passenger cars, light-duty vans, heavy-duty engines, non-road engines and motorcycles, offering detailed historical information and critical review. The book also provides detailed examples from SI and diesel engines and vehicles operating during various cycles, with a focus on how the engine behaves during transients and how this is reflected in emitted pollutants, CO2 and after-treatment systems operation. It describes the measurement methods for the testing of new vehicles and essential information on the procedure for creating a driving cycle. Lastly, it presents detailed technical specifications on the most important chassis-dynamometer cycles around the world, together with a direct comparison of those cycles.

  4. The adverse effects of high fat induced obesity on female reproductive cycle and hormones

    Science.gov (United States)

    Donthireddy, Laxminarasimha Reddy

    The prevalence of obesity, an established risk and progression factor for abnormal reproductive cycle and tissue damage in female mice. It leads to earlier puberty, menarche in young females and infertility. There are extensive range of consequences of obesity which includes type-2 diabetes, cardiovascular disease and insulin resistance. Obesity is the interaction between dietary intake, genes, life style and environment. The interplay of hormones estrogen, insulin, and leptin is well known on energy homeostasis and reproduction. The aim of this study is to determine the effect of high fat induced obesity on reproductive cycles and its hormonal abnormalities on mice model. Two week, 3 month and 8 month long normal (WT) and very high fat diet (VHFD) diet course is followed. When mice are fed with very high fat diet, there is a drastic increase in weight within the first week later. There was a significant (p<0.001) increase in leptin levels in 6 month VHFD treated animals. 2 week, 3 month and 6 month time interval pap smear test results showed number of cells, length of estrous cycle and phases of the estrous cycle changes with VHFD mice(n=30) compared to normal diet mice(n=10). These results also indicate that the changes in the reproductive cycles in VHFD treated female mice could be due to the changes in hormones. Histo-pathological analyses of kidney, ovary, liver, pancreas, heart and lungs showed remarkable changes in some tissue on exposure to very high fat. Highly deposited fat packets observed surrounding the hepatocytes and nerve cells.

  5. Crosslinked Carbon Nanotubes/Polyaniline Composites as a Pseudocapacitive Material with High Cycling Stability

    Directory of Open Access Journals (Sweden)

    Dong Liu

    2015-06-01

    Full Text Available The poor cycling stability of polyaniline (PANI limits its practical application as a pseudocapacitive material due to the volume change during the charge-discharge procedure. Herein, crosslinked carbon nanotubes/polyaniline (C-CNTs/PANI composites had been designed by the in situ chemical oxidative polymerization of aniline in the presence of crosslinked carbon nanotubes (C-CNTs, which were obtained by coupling of the functionalized carbon nanotubes with 1,4-benzoquinone. The composite showed a specific capacitance of 294 F/g at the scan rate of 10 mV/s, and could retain 95% of its initial specific capacitance after 1000 CV cycles. Such high electrochemical cycling stability resulting from the crosslinked skeleton of the C-CNTs makes them potential electrode materials for a supercapacitor.

  6. Controlled synthesis of porous anhydrous cobalt oxalate nanorods with high reversible capacity and excellent cycling stability

    International Nuclear Information System (INIS)

    Xu, Junmin; He, Lei; Liu, Hui; Han, Tao; Wang, Yongjian; Zhang, Changjin; Zhang, Yuheng

    2015-01-01

    Graphical abstract: Display Omitted -- Abstract: One-dimensional porous anhydrous cobalt oxalate nanorods are prepared via a facile water-controlled coprecipitate method followed by thermal annealing treatment under N 2 at 300 °C. The nanorods are characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. When evaluated as an anode material for lithium ion batteries, the nanorods exhibit high reversible specific capacity and excellent cycling stability (924 mA h g −1 at 50 mA g −1 after 100 cycles and 709 mA h g −1 at 200 mA g −1 after 220 cycles). This remarkable electrochemical performance is attributed to the one-dimensional porous nanostructure that can provide large electrode/electrolyte contact area and short lithium-ion diffusion pathway, meanwhile reduce the volume expansion during the repeated discharge/charge process

  7. High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Costante Mario Invernizzi

    2018-04-01

    Full Text Available Small-CHP (Combined Heat and Power systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas engine, the gas turbine (with internal combustion, the steam engine, engine working according to the Stirling and to the Rankine cycles, the last with organic fluids. In principle, also fuel cells could be used. In this paper, we focus on small size Rankine cycles (10–15 k W with organic working fluids. The assumed heat source is hot combustion gases at high temperature (900–950 ∘ C and we assume to use only single stages axial turbines. The need to work at high temperatures, limits the choice of the right organic working fluids. The calculation results show the limitation in the performances of simple cycles and suggest the opportunity to resort to complex (binary cycle configurations to achieve high net conversion efficiencies (15–16%.

  8. Free-Standing Hybrid Graphene Paper Encapsulating Nanostructures for High Cycle-Life Supercapacitors.

    Science.gov (United States)

    Jiao, Xinyan; Hao, Qingli; Xia, Xifeng; Lei, Wu; Ouyang, Yu; Ye, Haitao; Mandler, Daniel

    2018-03-09

    The incorporation of spacers between graphene sheets has been investigated as an effective method to improve the electrochemical performance of graphene papers (GPs) for supercapacitors. Here, we report the design of free-standing GP@NiO and GP@Ni hybrid GPs in which NiO nanoclusters and Ni nanoparticles are encapsulated into graphene sheets through electrostatic assembly and subsequent vacuum filtration. The encapsulated NiO nanoclusters and Ni nanoparticles can mitigate the restacking of graphene sheets, providing sufficient spaces for high-speed ion diffusion and electron transport. In addition, the spacers strongly bind to graphene sheets, which can efficiently improve the electrochemical stability. Therefore, at a current density of 0.5 A g -1 , the GP@NiO and GP@Ni electrodes exhibit higher specific capacitances of 306.9 and 246.1 F g -1 than the GP electrode (185.7 F g -1 ). The GP@NiO and GP@Ni electrodes exhibit capacitance retention of 98.7 % and 95.6 % after 10000 cycles, demonstrating an outstanding cycling stability. Additionally, the GP@NiO∥GP@Ni delivers excellent cycling stability (93.7 % after 10 000 cycles) and high energy density. These free-standing encapsulated hybrid GPs have great potential as electrode for high-performance supercapacitors. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Testing of High Thermal Cycling Stability of Low Strength Concrete as a Thermal Energy Storage Material

    Directory of Open Access Journals (Sweden)

    Chao Wu

    2016-09-01

    Full Text Available Concrete has the potential to become a solution for thermal energy storage (TES integrated in concentrating solar power (CSP systems due to its good thermal and mechanical properties and low cost of material. In this study, a low strength concrete (C20 is tested at high temperatures up to 600 °C. Specimens are thermally cycled at temperatures in the range of 400–300 °C, 500–300 °C, and 600–300 °C, which TES can reach in operation. For comparison, specimens also cycled at temperature in the range of 400–25 °C (room temperature, 500–25 °C, and 600–25 °C. It is found from the test results that cracks are not observed on the surfaces of concrete specimens until the temperature is elevated up to 500 °C. There is mechanical deterioration of concrete after exposure to high temperature, especially to high thermal cycles. The residual compressive strength of concrete after 10 thermal cycles between 600 °C and 300 °C is about 58.3%, but the specimens remain stable without spalling, indicating possible use of low strength concrete as a TES material.

  10. High-Level Synthesis of DSP Applications Using Adaptive Negative Cycle Detection

    Directory of Open Access Journals (Sweden)

    Nitin Chandrachoodan

    2002-09-01

    Full Text Available The problem of detecting negative weight cycles in a graph is examined in the context of the dynamic graph structures that arise in the process of high level synthesis (HLS. The concept of adaptive negative cycle detection is introduced, in which a graph changes over time and negative cycle detection needs to be done periodically, but not necessarily after every individual change. We present an algorithm for this problem, based on a novel extension of the well-known Bellman-Ford algorithm that allows us to adapt existing cycle information to the modified graph, and show by experiments that our algorithm significantly outperforms previous incremental approaches for dynamic graphs. In terms of applications, the adaptive technique leads to a very fast implementation of Lawlers algorithm for the computation of the maximum cycle mean (MCM of a graph, especially for a certain form of sparse graph. Such sparseness often occurs in practical circuits and systems, as demonstrated, for example, by the ISCAS 89/93 benchmarks. The application of the adaptive technique to design-space exploration (synthesis is also demonstrated by developing automated search techniques for scheduling iterative data-flow graphs.

  11. Analysis of zeotropic mixtures used in high-temperature Organic Rankine cycle

    International Nuclear Information System (INIS)

    Dong, Bensi; Xu, Guoqiang; Cai, Yi; Li, Haiwang

    2014-01-01

    Highlights: • Using mixtures leads to an efficiency increase compared to pure fluids. • MM/MDM (0.4/0.6) produces optimal cycle efficiency. • Lower temperature gradients of heat source and sink give rise to higher cycle efficiency. • Condensation step shows more effect than evaporation step on cycle efficiency. - Abstract: The paper investigates the performance of high-temperature Organic Rankine cycle (ORC) with zeotropic mixtures as working fluid. A numerical model, which has been validated by comparing with the published data, is developed to predict the first law thermal efficiency of the cycle. The effects of mixture concentration, temperature gradient of the heat transfer fluid, pinch temperature difference, pressure ratio, and condensation pressure on the first law efficiency are presented firstly using a purposely designed program, and then the suitable conditions for the described ORC are suggested based on the results of the simulation. It is demonstrated that the use of zeotropic mixtures leads to an efficiency increase compared to pure fluids

  12. High content image based analysis identifies cell cycle inhibitors as regulators of Ebola virus infection.

    Science.gov (United States)

    Kota, Krishna P; Benko, Jacqueline G; Mudhasani, Rajini; Retterer, Cary; Tran, Julie P; Bavari, Sina; Panchal, Rekha G

    2012-09-25

    Viruses modulate a number of host biological responses including the cell cycle to favor their replication. In this study, we developed a high-content imaging (HCI) assay to measure DNA content and identify different phases of the cell cycle. We then investigated the potential effects of cell cycle arrest on Ebola virus (EBOV) infection. Cells arrested in G1 phase by serum starvation or G1/S phase using aphidicolin or G2/M phase using nocodazole showed much reduced EBOV infection compared to the untreated control. Release of cells from serum starvation or aphidicolin block resulted in a time-dependent increase in the percentage of EBOV infected cells. The effect of EBOV infection on cell cycle progression was found to be cell-type dependent. Infection of asynchronous MCF-10A cells with EBOV resulted in a reduced number of cells in G2/M phase with concomitant increase of cells in G1 phase. However, these effects were not observed in HeLa or A549 cells. Together, our studies suggest that EBOV requires actively proliferating cells for efficient replication. Furthermore, multiplexing of HCI based assays to detect viral infection, cell cycle status and other phenotypic changes in a single cell population will provide useful information during screening campaigns using siRNA and small molecule therapeutics.

  13. High Content Image Based Analysis Identifies Cell Cycle Inhibitors as Regulators of Ebola Virus Infection

    Directory of Open Access Journals (Sweden)

    Sina Bavari

    2012-09-01

    Full Text Available Viruses modulate a number of host biological responses including the cell cycle to favor their replication. In this study, we developed a high-content imaging (HCI assay to measure DNA content and identify different phases of the cell cycle. We then investigated the potential effects of cell cycle arrest on Ebola virus (EBOV infection. Cells arrested in G1 phase by serum starvation or G1/S phase using aphidicolin or G2/M phase using nocodazole showed much reduced EBOV infection compared to the untreated control. Release of cells from serum starvation or aphidicolin block resulted in a time-dependent increase in the percentage of EBOV infected cells. The effect of EBOV infection on cell cycle progression was found to be cell-type dependent. Infection of asynchronous MCF-10A cells with EBOV resulted in a reduced number of cells in G2/M phase with concomitant increase of cells in G1 phase. However, these effects were not observed in HeLa or A549 cells. Together, our studies suggest that EBOV requires actively proliferating cells for efficient replication. Furthermore, multiplexing of HCI based assays to detect viral infection, cell cycle status and other phenotypic changes in a single cell population will provide useful information during screening campaigns using siRNA and small molecule therapeutics.

  14. High-cycle electromechanical aging of dielectric elastomer actuators with carbon-based electrodes

    Science.gov (United States)

    de Saint-Aubin, C. A.; Rosset, S.; Schlatter, S.; Shea, H.

    2018-07-01

    We present high-cycle aging tests of dielectric elastomer actuators (DEAs) based on silicone elastomers, reporting on the time-evolution of actuation strain and of electrode resistance over millions of cycles. We compare several types of carbon-based electrodes, and for the first time show how the choice of electrode has a dramatic influence on DEA aging. An expanding circle DEA configuration is used, consisting of a commercial silicone membrane with the following electrodes: commercial carbon grease applied manually, solvent-diluted carbon grease applied by stamping (pad printing), loose carbon black powder applied manually, carbon black powder suspension applied by inkjet-printing, and conductive silicone-carbon composite applied by stamping. The silicone-based DEAs with manually applied carbon grease electrodes show the shortest lifetime of less than 105 cycles at 5% strain, while the inkjet-printed carbon powder and the stamped silicone-carbon composite make for the most reliable devices, with lifetimes greater than 107 cycles at 5% strain. These results are valid for the specific dielectric and electrode configurations that were tested: using other dielectrics or electrode formulations would lead to different lifetimes and failure modes. We find that aging (as seen in the change in resistance and in actuation strain versus cycle number) is independent of the actuation frequency from 10 Hz to 200 Hz, and depends on the total accumulated time the DEA spends in an actuated state.

  15. Study on the fuel cycle cost of gas turbine high temperature reactor (GTHTR300). Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Takei, Masanobu; Katanishi, Shoji; Nakata, Tetsuo; Kunitomi, Kazuhiko [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Oda, Takefumi; Izumiya, Toru [Nuclear Fuel Industries, Ltd., Tokyo (Japan)

    2002-11-01

    In the basic design of gas turbine high temperature reactor (GTHTR300), reduction of the fuel cycle cost has a large benefit of improving overall plant economy. Then, fuel cycle cost was evaluated for GTHTR300. First, of fuel fabrication for high-temperature gas cooled reactor, since there was no actual experience with a commercial scale, a preliminary design for a fuel fabrication plant with annual processing of 7.7 ton-U sufficient four GTHTR300 was performed, and fuel fabrication cost was evaluated. Second, fuel cycle cost was evaluated based on the equilibrium cycle of GTHTR300. The factors which were considered in this cost evaluation include uranium price, conversion, enrichment, fabrication, storage of spent fuel, reprocessing, and waste disposal. The fuel cycle cost of GTHTR300 was estimated at about 1.07 yen/kWh. If the back-end cost of reprocessing and waste disposal is included and assumed to be nearly equivalent to LWR, the fuel cycle cost of GTHTR300 was estimated to be about 1.31 yen/kWh. Furthermore, the effects on fuel fabrication cost by such of fuel specification parameters as enrichment, the number of fuel types, and the layer thickness were considered. Even if the enrichment varies from 10 to 20%, the number of fuel types change from 1 to 4, the 1st layer thickness of fuel changes by 30 {mu}m, or the 2nd layer to the 4th layer thickness of fuel changes by 10 {mu}m, the impact on fuel fabrication cost was evaluated to be negligible. (author)

  16. High Energy, Long Cycle Life Lithium-ion Batteries for PHEV Application

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Donghai [Pennsylvania State Univ., University Park, PA (United States); Manthiram, Arumugam [Univ. of Texas, Austin, TX (United States); Wang, Chao-Yang [EC Power LLC, State College, PA (United States); Liu, Gao [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhang, Zhengcheng [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-05-15

    High-loading and high quality PSU Si anode has been optimized and fabricated. The electrochemical performance has been utilized. The PSU Si-graphite anode exhibits the mass loading of 5.8 mg/cm2, charge capacity of 850 mAh/ g and good cycling performance. This optimized electrode has been used for full-cell fabrication. The performance enhancement of Ni-rich materials can be achieved by a diversity of strategies. Higher Mn content and a small amount of Al doping can improve the electrochemical performance by suppressing interfacial side reactions with electrolytes, thus greatly benefiting the cyclability of the samples. Also, surface coatings of Li-rich materials and AlF3 are able to improve the performance stability of Ni-rich cathodes. One kilogram of optimized concentration-gradient LiNi0.76Co0.10Mn0.14O2 (CG) with careful control of composition, morphology and electrochemical performance was delivered to our collaborators. The sample achieved an initial specific capacity close to 190 mA h g-1 at C/10 rate and 180 mA h g-1 at C/3 rate as well as good cyclability in pouch full cells with a 4.4 V upper cut-off voltage at room temperature. Electrolyte additive with Si-N skeleton forms a less resistant SEI on the surface of silicon anode (from PSU) as evidenced by the evolution of the impedance at various lithiation/de-lithiation stages and the cycling data The prelithiation result demonstrates a solution processing method to achieve large area, uniform SLMP coating on well-made anode surface for the prelithiation of lithium-ion batteries. The prelithiation effect with this method is applied both in graphite half cells, graphite/NMC full cells, SiO half cells, SiO/NMC full cells, Si-Graphite half cells and Si-Graphite/NMC full cells with improvements in cycle performance and higher first cycle coulombic efficiency than their corresponding cells without SLMP prelithiation. As to the full

  17. Idle emissions from medium heavy-duty diesel and gasoline trucks.

    Science.gov (United States)

    Khan, A B M S; Clark, Nigel N; Gautam, Mridul; Wayne, W Scott; Thompson, Gregory J; Lyons, Donald W

    2009-03-01

    Idle emissions data from 19 medium heavy-duty diesel and gasoline trucks are presented in this paper. Emissions from these trucks were characterized using full-flow exhaust dilution as part of the Coordinating Research Council (CRC) Project E-55/59. Idle emissions data were not available from dedicated measurements, but were extracted from the continuous emissions data on the low-speed transient mode of the medium heavy-duty truck (MHDTLO) cycle. The four gasoline trucks produced very low oxides of nitrogen (NOx) and negligible particulate matter (PM) during idle. However, carbon monoxide (CO) and hydrocarbons (HCs) from these four trucks were approximately 285 and 153 g/hr on average, respectively. The gasoline trucks consumed substantially more fuel at an hourly rate (0.84 gal/hr) than their diesel counterparts (0.44 gal/hr) during idling. The diesel trucks, on the other hand, emitted higher NOx (79 g/hr) and comparatively higher PM (4.1 g/hr), on average, than the gasoline trucks (3.8 g/hr of NOx and 0.9 g/hr of PM, on average). Idle NOx emissions from diesel trucks were high for post-1992 model year engines, but no trends were observed for fuel consumption. Idle emissions and fuel consumption from the medium heavy-duty diesel trucks (MHDDTs) were marginally lower than those from the heavy heavy-duty diesel trucks (HHDDTs), previously reported in the literature.

  18. The mitochondrial pyruvate carrier mediates high fat diet-induced increases in hepatic TCA cycle capacity.

    Science.gov (United States)

    Rauckhorst, Adam J; Gray, Lawrence R; Sheldon, Ryan D; Fu, Xiaorong; Pewa, Alvin D; Feddersen, Charlotte R; Dupuy, Adam J; Gibson-Corley, Katherine N; Cox, James E; Burgess, Shawn C; Taylor, Eric B

    2017-11-01

    Excessive hepatic gluconeogenesis is a defining feature of type 2 diabetes (T2D). Most gluconeogenic flux is routed through mitochondria. The mitochondrial pyruvate carrier (MPC) transports pyruvate from the cytosol into the mitochondrial matrix, thereby gating pyruvate-driven gluconeogenesis. Disruption of the hepatocyte MPC attenuates hyperglycemia in mice during high fat diet (HFD)-induced obesity but exerts minimal effects on glycemia in normal chow diet (NCD)-fed conditions. The goal of this investigation was to test whether hepatocyte MPC disruption provides sustained protection from hyperglycemia during long-term HFD and the differential effects of hepatocyte MPC disruption on TCA cycle metabolism in NCD versus HFD conditions. We utilized long-term high fat feeding, serial measurements of postabsorptive blood glucose and metabolomic profiling and 13 C-lactate/ 13 C-pyruvate tracing to investigate the contribution of the MPC to hyperglycemia and altered hepatic TCA cycle metabolism during HFD-induced obesity. Hepatocyte MPC disruption resulted in long-term attenuation of hyperglycemia induced by HFD. HFD increased hepatic mitochondrial pyruvate utilization and TCA cycle capacity in an MPC-dependent manner. Furthermore, MPC disruption decreased progression of fibrosis and levels of transcript markers of inflammation. By contributing to chronic hyperglycemia, fibrosis, and TCA cycle expansion, the hepatocyte MPC is a key mediator of the pathophysiology induced in the HFD model of T2D. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  19. Cooling of nuclear power stations with high temperature reactors and helium turbine cycles

    International Nuclear Information System (INIS)

    Foerster, S.; Hewing, G.

    1977-01-01

    On nuclear power stations with high temperature reactors and helium turbine cycles (HTR-single circuits) the residual heat from the energy conversion process in the primary and intermediate coolers is removed from cycled gas, helium. Water, which is circulated for safety reasons through a closed circuit, is used for cooling. The primary and intermediate coolers as well as other cooling equipment of the power plant are installed within the reactor building. The heat from the helium turbine cycle is removed to the environment most effectively by natural draught cooling towers. In this way a net plant efficiency of about 40% is attainable. The low quantities of residual heat thereby produced and the high (in comparison with power stations with steam turbine cycles) cooling agent pressure and cooling water reheat pressure in the circulating coolers enable an economically favourable design of the overall 'cold end' to be expected. In the so-called unit range it is possible to make do with one or two cooling towers. Known techniques and existing operating experience can be used for these dry cooling towers. After-heat removal reactor shutdown is effected by a separate, redundant cooling system with forced air dry coolers. The heat from the cooling process at such locations in the power station is removed to the environment either by a forced air dry cooling installation or by a wet cooling system. (orig.) [de

  20. Coupling of Modular High-Temperature Gas-Cooled Reactor with Supercritical Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shutang Zhu

    2008-01-01

    Full Text Available This paper presents investigations on the possible combination of modular high-temperature gas-cooled reactor (MHTGR technology with the supercritical (SC steam turbine technology and the prospective deployments of the MHTGR SC power plant. Energy conversion efficiency of steam turbine cycle can be improved by increasing the main steam pressure and temperature. Investigations on SC water reactor (SCWR reveal that the development of SCWR power plants still needs further research and development. The MHTGR SC plant coupling the existing technologies of current MHTGR module design with operation experiences of SC FPP will achieve high cycle efficiency in addition to its inherent safety. The standard once-reheat SC steam turbine cycle and the once-reheat steam cycle with life-steam have been studied and corresponding parameters were computed. Efficiencies of thermodynamic processes of MHTGR SC plants were analyzed, while comparisons were made between an MHTGR SC plant and a designed advanced passive PWR - AP1000. It was shown that the net plant efficiency of an MHTGR SC plant can reach 45% or above, 30% higher than that of AP1000 (35% net efficiency. Furthermore, an MHTGR SC plant has higher environmental competitiveness without emission of greenhouse gases and other pollutants.

  1. Fatigue performance of laser additive manufactured Ti-6Al-4V in very high cycle fatigue (VHCF regime up to 109 cycles

    Directory of Open Access Journals (Sweden)

    Eric eWycisk

    2015-12-01

    Full Text Available Additive manufacturing technologies are in the process of establishing themselves as an alternative production technology to conventional manufacturing such as casting or milling. Especially laser additive manufacturing (LAM enables the production of metallic parts with mechanical properties comparable to conventionally manufactured components. Due to the high geometrical freedom in LAM the technology enables the production of ultra-light weight designs and therefore gains increasing importance in aircraft and space industry. The high quality standards of these industries demand predictability of material properties for static and dynamic load cases. However, fatigue properties especially in the very high cycle fatigue regime until 109 cycles have not been sufficiently determined yet. Therefore this paper presents an analysis of fatigue properties of laser additive manufactured Ti-6Al-4V under cyclic tension-tension until 107 cycles and tension-compression load until 109 cycles.For the analysis of laser additive manufactured titanium alloy Ti-6Al-4V Woehler fatigue tests under tension-tension and tension-compression were carried out in the high cycle and very high cycle fatigue regime. Specimens in stress-relieved as well as hot-isostatic-pressed conditions were analyzed regarding crack initiation site, mean stress sensitivity and overall fatigue performance. The determined fatigue properties show values in the range of conventionally manufactured Ti-6Al-4V with particularly good performance for hot-isostatic-pressed additive-manufactured material. For all conditions the results show no conventional fatigue limit but a constant increase in fatigue life with decreasing loads. No effects of test frequency on life span could be determined. However, independently of testing principle, a shift of crack initiation from surface to internal initiation could be observed with increasing cycles to failure.

  2. Study on high-cycle fatigue behavior of candidate Fe-Cr-Ni alloys for SCWR

    International Nuclear Information System (INIS)

    Zhao Yuxiang; Liu Guiliang; Tang Rui; Xiong Ru; Qiao Yingjie

    2014-01-01

    In the design for supercritical water reactor (SCWR), the operating temperature, pressure, burn up and irradiation damage are very high, so it seems vital to make correct choice of structural materials in core and obtain their key application behavior which would beneficial the research and development of SCWR. In this paper, the high cycle fatigue (HCF) tests of commerce austenite alloys including 6XN and 825 were conducted under bending and rotating loads at room temperature (RT) as well as at 550 ℃ in air. The experimental data were analyzed and the S-N curves were processed, the fracture morphology was also observed by SEM. The results indicate that the fatigue limited stresses at RT for the 2 Fe-Cr-Ni alloy were in such order of 825 < 6XN, which consistent with the order of their tensile strength. Elevated temperature would accelerate the oxidation of the specimen and therefore the fatigue life would decrease, among them 6XN was more sensitive to high temperature with the larger decreasing tendency which make the fatigue limited stress of the two alloys more closer at 550 ℃. While 825 is more sensitive to the stress cycles. All the two alloys have good resistance to high cycle fatigue when comparing their experimental data with the calculated value from the empirical formula. The fracture morphology presents areas of crack initiation, crack growth and fracture, the fracture area has much dimples. This work can be applied to the conceptional design for SCWR. (authors)

  3. Modeling and Depletion Simulations for a High Flux Isotope Reactor Cycle with a Representative Experiment Loading

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Betzler, Ben [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Hirtz, Gregory John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Ilas, Germina [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division; Sunny, Eva [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Reactor and Nuclear Systems Division

    2016-09-01

    The purpose of this report is to document a high-fidelity VESTA/MCNP High Flux Isotope Reactor (HFIR) core model that features a new, representative experiment loading. This model, which represents the current, high-enriched uranium fuel core, will serve as a reference for low-enriched uranium conversion studies, safety-basis calculations, and other research activities. A new experiment loading model was developed to better represent current, typical experiment loadings, in comparison to the experiment loading included in the model for Cycle 400 (operated in 2004). The new experiment loading model for the flux trap target region includes full length 252Cf production targets, 75Se production capsules, 63Ni production capsules, a 188W production capsule, and various materials irradiation targets. Fully loaded 238Pu production targets are modeled in eleven vertical experiment facilities located in the beryllium reflector. Other changes compared to the Cycle 400 model are the high-fidelity modeling of the fuel element side plates and the material composition of the control elements. Results obtained from the depletion simulations with the new model are presented, with a focus on time-dependent isotopic composition of irradiated fuel and single cycle isotope production metrics.

  4. A vision for an ultra-high resolution integrated water cycle observation and prediction system

    Science.gov (United States)

    Houser, P. R.

    2013-05-01

    Society's welfare, progress, and sustainable economic growth—and life itself—depend on the abundance and vigorous cycling and replenishing of water throughout the global environment. The water cycle operates on a continuum of time and space scales and exchanges large amounts of energy as water undergoes phase changes and is moved from one part of the Earth system to another. We must move toward an integrated observation and prediction paradigm that addresses broad local-to-global science and application issues by realizing synergies associated with multiple, coordinated observations and prediction systems. A central challenge of a future water and energy cycle observation strategy is to progress from single variable water-cycle instruments to multivariable integrated instruments in electromagnetic-band families. The microwave range in the electromagnetic spectrum is ideally suited for sensing the state and abundance of water because of water's dielectric properties. Eventually, a dedicated high-resolution water-cycle microwave-based satellite mission may be possible based on large-aperture antenna technology that can harvest the synergy that would be afforded by simultaneous multichannel active and passive microwave measurements. A partial demonstration of these ideas can even be realized with existing microwave satellite observations to support advanced multivariate retrieval methods that can exploit the totality of the microwave spectral information. The simultaneous multichannel active and passive microwave retrieval would allow improved-accuracy retrievals that are not possible with isolated measurements. Furthermore, the simultaneous monitoring of several of the land, atmospheric, oceanic, and cryospheric states brings synergies that will substantially enhance understanding of the global water and energy cycle as a system. The multichannel approach also affords advantages to some constituent retrievals—for instance, simultaneous retrieval of vegetation

  5. Stamp duties in Indian states - a case for reform

    OpenAIRE

    Alm, James; Annez, Patricia; Modi, Arbind

    2004-01-01

    The authors review the options for reform of stamp duties on immovable property transfers collected by Indian state governments. After briefly reviewing some of the many administrative difficulties experienced with the tax, they turn to an examination of its economic impacts. A review of stamp duties internationally indicates that Indian rates are exceptionally high, at rates often above 1...

  6. A "high severity" spruce beetle outbreak in Wyoming causes moderate-severity carbon cycle perturbations

    Science.gov (United States)

    Berryman, E.; Frank, J. M.; Speckman, H. N.; Bradford, J. B.; Ryan, M. G.; Massman, W. J.; Hawbaker, T. J.

    2017-12-01

    Bark beetle outbreaks in Western North American forests are often considered a high-severity disturbance from a carbon (C) cycling perspective, but field measurements that quantify impacts on C dynamics are very limited. Often, factors out of the researcher's control complicate the separation of beetle impacts from other drivers of C cycling variability and restrict statistical inference. Fortuitously, we had four years of pre-spruce beetle outbreak C cycle measurements in a subalpine forest in southeastern Wyoming (Glacier Lakes Ecosystem Experiments Site, or GLEES) and sustained intermittent monitoring for nearly a decade after the outbreak. Here, we synthesize published and unpublished pre- and post-outbreak measurements of key C cycle stocks and fluxes at GLEES. Multiple lines of evidence, including chamber measurements, eddy covariance measurements, and tracking of soil and forest floor C pools over time, point to the GLEES outbreak as a moderate-severity disturbance for C loss to the atmosphere, despite 70% to 80% of overstory tree death. Reductions in NEE were short-lived and the forest quickly returned to a carbon-neutral state, likely driven by an uptick in understory growth. Effect of mortality on the C cycle was asymmetrical, with a 50% reduction in net carbon uptake (NEE) two years into the outbreak, yet no measureable change in either ecosystem or growing season soil respiration. A small pulse in soil respiration occurred but was only detectable during the winter and amounted to < 10% of NEE. Possible reasons for the lack of measureable respiration response are discussed with emphasis on lessons learned for monitoring and modeling future outbreaks. We suggest a comprehensive assessment and definition of "moderate-severity" disturbances for Western forests and suggest that all tree mortality events may not be high-severity when it comes to C fluxes.

  7. Development of a high cycle vibration fatigue diagnostic system with non-contact vibration sensing

    International Nuclear Information System (INIS)

    Nekomoto, Yoshitsugu; Tanaka, Masanori; Nishimura, Moritatsu; Matsumoto, Kenji; O'shima, Eiji

    2004-01-01

    Nuclear power plants have a large number of pipes. These small-diameter pipe branches in particles are often damaged due to high-cycle fatigue. In order to ensure the reliability of a plant it is important to detect fatigue damages in pipe branches at an early stage and to develop the technology to predict and diagnose the advancement of fatigue. Further, in order to carry out the diagnosis of the piping system effectively during operation, non-contact evaluation is useful. Hence, we have developed a ''high-cycle fatigue diagnostic system with non-contact vibration sensing'', which measures the vibration of the pipe branch using a non-contact sensor. (author)

  8. Waste arisings from a high-temperature reactor with a uranium-thorium fuel cycle

    International Nuclear Information System (INIS)

    1979-09-01

    This paper presents an equilibrium-recycle condition flow sheet for a high-temperature gas-cooled reactor (HTR) fuel cycle which uses thorium and high-enriched uranium (93% U-235) as makeup fuel. INFCE Working Group 7 defined percentage losses to various waste streams are used to adjust the heavy-element mass flows per gigawatt-year of electricity generated. Thorium and bred U-233 are recycled following Thorex reprocessing. Fissile U-235 is recycled one time following Purex reprocessing and then is discarded to waste. Plutonium and other transuranics are discarded to waste. Included are estimates of volume, radioactivity, and heavy-element content of wastes arising from HTR fuel element fabrication; HTR operation, maintenance, and decommissioning; and reprocessing spent fuel where the waste is unique to the HTR fuel cycle

  9. Effects of HTGR helium on the high cycle fatigue of structural materials

    International Nuclear Information System (INIS)

    Soo, P.; Sabatini, R.L.; Gerlach, L.

    1982-01-01

    High cycle fatigue tests have been conducted on Incoloy 800H and Hastelloy X in air and in HTGR helium environments containing low and high levels of moisture. For the helium environments, a higher mositure level usually gives a lower fatigue strength. For air, however, the strength is usually much lower than those for helium. For long test times at higher test temperatures, the fatigue strengths for Incoloy 800H often show a large decrease, and the fatigue limits are much lower than those anticipated from low cycle tests. Optical and scanning electron microscope observations were made to correlate fatigue life with surface and bulk microstructural changes in the material during test. Oxide scale cracking and spallation, surface recrystallization and intergranular attack appear to contribute to losses in fatigue strength

  10. Effect of cyclic pre-strain on low cycle fatigue life at middle high temperature

    International Nuclear Information System (INIS)

    Nakane, Motoki; Kanno, Satoshi; Takagi, Yoshio

    2011-01-01

    This study examined the effect of cyclic plastic pre-strain on low cycle fatigue life at middle high temperature to evaluate the structural integrity of the nuclear components introduced plastic strain to the local portion by the large seismic load. The materials selected in this study were austenitic steel (SUS316NG) and ferritic steel (SFVQ1A, STS410: JIS (Japanese Industrial Standards). The low cycle fatigue tests at RT and middle high temperature (300 degrees C) were carried out using cyclic plastic pre-strained materials. The results obtained here show that the damage by the cyclic plastic pre-strain, which is equivalent to usage factor UF=0.2, does not affect the fatigue lives of the materials. In addition, it is confirmed that the estimation based on the usage factor UF can also be useful for the life prediction at 300 degrees C as well as RT. (author)

  11. Concept Design for a High Temperature Helium Brayton Cycle with Interstage Heating and Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vernon, Milton E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pickard, Paul S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    The primary metric for the viability of these next generation nuclear power plants will be the cost of generated electricity. One important component in achieving these objectives is the development of power conversion technologies that maximize the electrical power output of these advanced reactors for a given thermal power. More efficient power conversion systems can directly reduce the cost of nuclear generated electricity and therefore advanced power conversion cycle research is an important area of investigation for the Generation IV Program. Brayton cycles using inert or other gas working fluids, have the potential to take advantage of the higher outlet temperature range of Generation IV systems and allow substantial increases in nuclear power conversion efficiency, and potentially reductions in power conversion system capital costs compared to the steam Rankine cycle used in current light water reactors. For the Very High Temperature Reactor (VHTR), Helium Brayton cycles which can operate in the 900 to 950 C range have been the focus of power conversion research. Previous Generation IV studies examined several options for He Brayton cycles that could increase efficiency with acceptable capital cost implications. At these high outlet temperatures, Interstage Heating and Cooling (IHC) was shown to provide significant efficiency improvement (a few to 12%) but required increased system complexity and therefore had potential for increased costs. These scoping studies identified the potential for increased efficiency, but a more detailed analysis of the turbomachinery and heat exchanger sizes and costs was needed to determine whether this approach could be cost effective. The purpose of this study is to examine the turbomachinery and heat exchanger implications of interstage heating and cooling configurations. In general, this analysis illustrates that these engineering considerations introduce new constraints to the design of IHC systems that may require

  12. Three-Dimensional Water and Carbon Cycle Modeling at High Spatial-Temporal Resolutions

    Science.gov (United States)

    Liao, C.; Zhuang, Q.

    2017-12-01

    Terrestrial ecosystems in cryosphere are very sensitive to the global climate change due to the presence of snow covers, mountain glaciers and permafrost, especially when the increase in near surface air temperature is almost twice as large as the global average. However, few studies have investigated the water and carbon cycle dynamics using process-based hydrological and biogeochemistry modeling approach. In this study, we used three-dimensional modeling approach at high spatial-temporal resolutions to investigate the water and carbon cycle dynamics for the Tanana Flats Basin in interior Alaska with emphases on dissolved organic carbon (DOC) dynamics. The results have shown that: (1) lateral flow plays an important role in water and carbon cycle, especially in dissolved organic carbon (DOC) dynamics. (2) approximately 2.0 × 104 kg C yr-1 DOC is exported to the hydrological networks and it compromises 1% and 0.01% of total annual gross primary production (GPP) and total organic carbon stored in soil, respectively. This study has established an operational and flexible framework to investigate and predict the water and carbon cycle dynamics under the changing climate.

  13. Graphene and maghemite composites based supercapacitors delivering high volumetric capacitance and extraordinary cycling stability

    International Nuclear Information System (INIS)

    Zhang, Haitao; Zhang, Xiong; Lin, He; Wang, Kai; Sun, Xianzhong; Xu, Nansheng; Li, Chen; Ma, Yanwei

    2015-01-01

    Metal oxides (like MnO 2 , Fe 2 O 3 , and Co 3 O 4 , etc) based supercapacitors have disadvantages, such as low volumetric capacitance for thick-film electrodes, or short cycling life because a Faradaic process involves chemical changes of state of the reactant species. In the present work, we report that supercapacitors based on reduced graphene oxide and maghemite (γ-Fe 2 O 3 ) composites (GγM) exhibit superior performance. GγM electrodes with average electrode thickness up to ∼60 μm have a high volumetric capacitance of 230 F cm −3 , together with an outstanding electrode package density of 1.44 g cm −3 . Particularly, the GγM electrodes have excellent cycling performance of ∼90% capacitance retention over 100,000 galvanostatic charge–discharge cycles or voltage floating at 0.9 V for 300 h. No detectable change in phase and an effective inhibition of γ-Fe 2 O 3 refinement after cycle-life test are confirmed by X-ray diffraction and transmission electron microscopy

  14. A design of high resolution one-clock-cycle TDC based on FPGA

    International Nuclear Information System (INIS)

    Qi Ji; Deng Zhi; Liu Yinong

    2011-01-01

    It describes an FPGA-based high resolution TDC. Using delay chain and Wave Union methods, this TDC has a resolution of 9 ps, which is comparable to ASIC TDC. The design uses XORs and MUXs to implement a quick 1 -cycle encoder, which reduces the dead time. Self-calibration method makes the design easy to be migrated into other FPGAs. This TDC can be used in TOF experiment, medical imaging system, etc (authors)

  15. Experimental investigation of high cycle thermal fatigue in a T-junction piping system

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, P. Karthick; Kulenovic, Rudi; Laurien, Eckart [Stuttgart Univ. (Germany). Inst. of Nuclear Technology and Energy Systems (IKE)

    2015-10-15

    High cycle thermal fatigue damage of structure in the vicinity of T-junction piping systems in nuclear power plants is of importance. Mixing of coolant streams at significant temperature differences causes thermal fluctuations near piping wall leading to gradual thermal degradation. Flow mixing in a T-junction is performed. The determined factors result in bending stresses being imposed on the piping system ('Banana effect').

  16. High-cycle fatigue of Ni-base superalloy Inconel 713LC

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Konečná, R.

    2010-01-01

    Roč. 32, č. 6 (2010), s. 908-913 ISSN 0142-1123 R&D Projects: GA MPO FT-TA4/023; GA MŠk MEB080812 Institutional research plan: CEZ:AV0Z20410507 Keywords : IN 713LC * High-cycle fatigue * Effect of mean stress * Fractography * Casting defetcts * Extreme value statistics Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.799, year: 2010

  17. Project Management Life Cycle Models to Improve Management in High-rise Construction

    Science.gov (United States)

    Burmistrov, Andrey; Siniavina, Maria; Iliashenko, Oksana

    2018-03-01

    The paper describes a possibility to improve project management in high-rise buildings construction through the use of various Project Management Life Cycle Models (PMLC models) based on traditional and agile project management approaches. Moreover, the paper describes, how the split the whole large-scale project to the "project chain" will create the factor for better manageability of the large-scale buildings project and increase the efficiency of the activities of all participants in such projects.

  18. Project Management Life Cycle Models to Improve Management in High-rise Construction

    Directory of Open Access Journals (Sweden)

    Burmistrov Andrey

    2018-01-01

    Full Text Available The paper describes a possibility to improve project management in high-rise buildings construction through the use of various Project Management Life Cycle Models (PMLC models based on traditional and agile project management approaches. Moreover, the paper describes, how the split the whole large-scale project to the "project chain" will create the factor for better manageability of the large-scale buildings project and increase the efficiency of the activities of all participants in such projects.

  19. Copper hexacyanoferrate battery electrodes with long cycle life and high power

    KAUST Repository

    Wessells, Colin D.; Huggins, Robert A.; Cui, Yi

    2011-01-01

    Short-term transients, including those related to wind and solar sources, present challenges to the electrical grid. Stationary energy storage systems that can operate for many cycles, at high power, with high round-trip energy efficiency, and at low cost are required. Existing energy storage technologies cannot satisfy these requirements. Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery electrode in inexpensive aqueous electrolytes. After 40,000 deep discharge cycles at a 17g-C rate, 83% of the original capacity of copper hexacyanoferrate is retained. Even at a very high cycling rate of 83g-C, two thirds of its maximum discharge capacity is observed. At modest current densities, round-trip energy efficiencies of 99% can be achieved. The low-cost, scalable, room-temperature co-precipitation synthesis and excellent electrode performance of copper hexacyanoferrate make it attractive for large-scale energy storage systems. © 2011 Macmillan Publishers Limited. All rights reserved.

  20. Copper hexacyanoferrate battery electrodes with long cycle life and high power

    KAUST Repository

    Wessells, Colin D.

    2011-11-22

    Short-term transients, including those related to wind and solar sources, present challenges to the electrical grid. Stationary energy storage systems that can operate for many cycles, at high power, with high round-trip energy efficiency, and at low cost are required. Existing energy storage technologies cannot satisfy these requirements. Here we show that crystalline nanoparticles of copper hexacyanoferrate, which has an ultra-low strain open framework structure, can be operated as a battery electrode in inexpensive aqueous electrolytes. After 40,000 deep discharge cycles at a 17g-C rate, 83% of the original capacity of copper hexacyanoferrate is retained. Even at a very high cycling rate of 83g-C, two thirds of its maximum discharge capacity is observed. At modest current densities, round-trip energy efficiencies of 99% can be achieved. The low-cost, scalable, room-temperature co-precipitation synthesis and excellent electrode performance of copper hexacyanoferrate make it attractive for large-scale energy storage systems. © 2011 Macmillan Publishers Limited. All rights reserved.

  1. Empirical membrane lifetime model for heavy duty fuel cell systems

    Science.gov (United States)

    Macauley, Natalia; Watson, Mark; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

    2016-12-01

    Heavy duty fuel cells used in transportation system applications such as transit buses expose the fuel cell membranes to conditions that can lead to lifetime-limiting membrane failure via combined chemical and mechanical degradation. Highly durable membranes and reliable predictive models are therefore needed in order to achieve the ultimate heavy duty fuel cell lifetime target of 25,000 h. In the present work, an empirical membrane lifetime model was developed based on laboratory data from a suite of accelerated membrane durability tests. The model considers the effects of cell voltage, temperature, oxygen concentration, humidity cycling, humidity level, and platinum in the membrane using inverse power law and exponential relationships within the framework of a general log-linear Weibull life-stress statistical distribution. The obtained model is capable of extrapolating the membrane lifetime from accelerated test conditions to use level conditions during field operation. Based on typical conditions for the Whistler, British Columbia fuel cell transit bus fleet, the model predicts a stack lifetime of 17,500 h and a membrane leak initiation time of 9200 h. Validation performed with the aid of a field operated stack confirmed the initial goal of the model to predict membrane lifetime within 20% of the actual operating time.

  2. Life?cycle impacts of ethanol production from spruce wood chips under high-gravity conditions

    OpenAIRE

    Janssen, Matty; Xiros, Charilaos; Tillman, Anne-Marie

    2016-01-01

    Background Development of more sustainable biofuel production processes is ongoing, and technology to run these processes at a high dry matter content, also called high-gravity conditions, is one option. This paper presents the results of a life?cycle assessment (LCA) of such a technology currently in development for the production of bio-ethanol from spruce wood chips. Results The cradle-to-gate LCA used lab results from a set of 30 experiments (or process configurations) in which the main p...

  3. Low cycle fatigue and creep fatigue behavior of alloy 617 at high temperature

    International Nuclear Information System (INIS)

    Cabet, Celine; Carroll, Laura; Wright, Richard

    2013-01-01

    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 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 mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure. (authors)

  4. High-cycle fatigue behavior of ultrafine-grained austenitic stainless and TWIP steels

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, A.S. [Materials Engineering Laboratory (4KOMT), Box 4200, University of Oulu, 90014 Oulu (Finland); Metallurgical and Materials Engineering Department, Faculty of Petroleum and Mining Engineering, Suez Canal University, Box 43721, Suez (Egypt); Karjalainen, L.P., E-mail: pentti.karjalainen@oulu.fi [Materials Engineering Laboratory (4KOMT), Box 4200, University of Oulu, 90014 Oulu (Finland)

    2010-08-20

    High-cycle fatigue behavior of ultrafine-grained (UFG) 17Cr-7Ni Type 301LN austenitic stainless and high-Mn Fe-22Mn-0.6C TWIP steels were investigated in a reversed plane bending fatigue and compared to the behavior of steels with conventional coarse grain (CG) size. Optical, scanning and transmission electron microscopy were used to examine fatigue damage mechanisms. Testing showed that the fatigue limits leading to fatigue life beyond 4 x 10{sup 6} cycles were about 630 MPa for 301LN while being 560 MPa for TWIP steel, and being 0.59 and 0.5 of the tensile strength respectively. The CG counterparts were measured to have the fatigue limits of 350 and 400 MPa. The primary damage caused by fatigue took place by grain boundary cracking in UFG 301LN, while slip band cracking occurred in CG 301LN. However, in the case of TWIP steel, the fatigue damage mechanism is similar in spite of the grain size. In the course of cycling neither the formation of a martensite structure nor mechanical twinning occurs, but intense slip bands are created with extrusions and intrusions. Fatigue crack initiates preferentially on grain and twin boundaries, and especially in the intersection sites of slip bands and boundaries.

  5. Comparison of the Organic Flash Cycle (OFC) to other advanced vapor cycles for intermediate and high temperature waste heat reclamation and solar thermal energy

    International Nuclear Information System (INIS)

    Ho, Tony; Mao, Samuel S.; Greif, Ralph

    2012-01-01

    The Organic Flash Cycle (OFC) is proposed as a vapor power cycle that could potentially improve the efficiency with which high and intermediate temperature finite thermal sources are utilized. The OFC's aim is to improve temperature matching and reduce exergy losses during heat addition. A theoretical investigation is conducted using high accuracy equations of state such as BACKONE, Span–Wagner, and REFPROP in a detailed thermodynamic and exergetic analysis. The study examines 10 different aromatic hydrocarbons and siloxanes as potential working fluids. Comparisons are drawn between the OFC and an optimized basic Organic Rankine Cycle (ORC), a zeotropic Rankine cycle using a binary ammonia-water mixture, and a transcritical CO 2 cycle. Results showed aromatic hydrocarbons to be the better suited working fluid for the ORC and OFC due to higher power output and less complex turbine designs. Results also showed that the single flash OFC achieves comparable utilization efficiencies to the optimized basic ORC. Although the OFC improved heat addition exergetic efficiency, this advantage was negated by irreversibilities introduced during flash evaporation. A number of potentially significant improvements to the OFC are possible though which includes using a secondary flash stage or replacing the throttling valve with a two-phase expander. -- Highlights: ► The Organic Flash Cycle (OFC) is proposed to improve temperature matching. ► Ten aromatic hydrocarbon and siloxane working fluids are considered. ► Accurate equations of state explicit in Helmholtz energy are used in the analysis. ► The OFC is compared to basic ORCs, zeotropic, and transcritical cycles. ► The OFC achieves comparable power output to the optimized basic ORC.

  6. Interaction of high cycle fatigue and creep in 9%Cr-1%Mo steel at elevated temperature

    International Nuclear Information System (INIS)

    Vasina, R.; Lukas, P.; Kunz, L.; Sklenicka, V.

    1995-01-01

    High-cycle-fatigue/creep experiments were performed on a 9%Cr-1%Mo tempered martensite ferritic steel at 873 K in air. The stress ratio R = σ min /σ max ranged from -1 (''pure'' fatigue) to 1 (''pure'' creep). The maximum stress σ max was kept constant at 240 MPa.The lifetime depends on the stress ratio R in a non-monotonic way. In the stress ratio interval 0.6 mean of the stress cycle. In the stress ratio interval -1 a . The fatigue/creep interaction occurs in between these intervals. The fatigue/creep loading induces transformation of the tempered martensite ferritic structure into an equiaxed subgrain structure. The resulting subgrain size depends strongly on the stress ratio. (author)

  7. Notch size effects on high cycle fatigue limit stress of Udimet 720

    International Nuclear Information System (INIS)

    Ren Weiju; Nicholas, Theodore

    2003-01-01

    Notch size effects on the high cycle fatigue (HCF) limit stress of Ni-base superalloy Udimet 720 were investigated on cylindrical specimens with three notch sizes of the same stress concentration factor K t =2.74. The HCF limit stress corresponding to a life of 10 6 cycles was experimentally determined at a stress ratio of 0.1 and a frequency of 25 Hz at room temperature. The stresses were calculated using finite element analysis (FEA) and the specimens analyzed using scanning electron microscopy (SEM). Test results show that at the same K t value, notch size can slightly affect the HCF limit stress of U720 when notch root plasticity occurs. FEA and SEM results reveal that the notch size effects are influenced by a complicated combination of the stress and plastic strain fields at the notch tip, the nominal stress, and the effects of prior plastic deformation on fatigue crack initiation

  8. Fatigue of Austempered Ductile Iron with Two Strength Grades in Very High Cycle Regime

    Science.gov (United States)

    Zhang, Jiwang; Li, Wei; Song, Qingpeng; Zhang, Ning; Lu, Liantao

    2016-03-01

    In this study, Austempered ductile irons (ADIs) with two different strength grades were produced and the fatigue properties were measured at 109 cycles. The results show that the S-N curves give a typical step-wise shape and there is no fatigue limit in the very high cycle fatigue regime. The two grades ADI have the similar fracture behaviors and fatigue failure can initiate from defects at specimen surface and subsurface zone. On the fracture surfaces of some specimens, the `granular-bright-facet' area with rich carbon distribution is observed in the vicinity of the defect. The microstructure affects the crack behaviors at the early propagation stage. The ADI with upper and lower bainite shows higher fatigue strength compared with the ADI with coarse upper bainite.

  9. Climate Change and Individual Duties

    OpenAIRE

    Augustin Fragnière

    2016-01-01

    Tackling climate change has often been considered the responsibility of national governments. But do individuals also have a duty to act in the face of this problem? In particular do they have a duty to adopt a greener lifestyle or to press their government to act? This review critically examines the arguments provided for and against such duties in the relevant philosophic literature. It first discusses the problem of causal inefficacy—namely the fact that individual greenhouse gas emissions...

  10. Optimization of advanced high-temperature Brayton cycles with multiple reheat stages

    International Nuclear Information System (INIS)

    Haihua Zhao; Per F Peterson

    2005-01-01

    Full text of publication follows: This paper presents an overview and a few point designs for multiple-reheat Brayton cycle power conversion systems using high temperature molten salts (or liquid metals). All designs are derived from the General Atomics GT-MHR power conversion unit (PCU). The GT-MHR PCU is currently the only closed helium cycle system that has undergone detailed engineering design analysis, and that has turbomachinery which is sufficiently large to extrapolate to a >1000 MW(e) multiple reheat gas cycle power conversion system. Analysis shows that, with relatively small engineering modifications, multiple GT-MHR PCU's can be connected together to create a power conversion system in the >1000 MW(e) class. The resulting power conversion system is quite compact, and results in what is likely the minimum gas duct volume possible for a multiple-reheat system. To realize this, compact offset fin plate type liquid-to-gas heat exchangers (power densities from 10 to 120 MW/m 3 ) are needed. Both metal and non-metal heat exchangers are being investigated for high-temperature, gas-cooled reactors for temperatures to 1000 deg. C. Recent high temperature heat exchanger studies for nuclear hydrogen production has suggested that carbon-coated composite materials such as liquid silicon infiltrated chopped fiber carbon-carbon preformed material potentially could be used to fabricate plate fin heat exchangers with reasonable price. Different fluids such as helium, nitrogen and helium mixture, and supercritical CO 2 are compared for these multiple reheat Brayton cycles. Nitrogen and helium mixture cycle need about 40% more total PCU volume than helium cycle while keeping the same net cycle efficiency. Supercritical CO 2 needs very high pressure to optimize. Due to relatively detailed design for components such as heat exchangers, turbomachinery, and duct system, relatively accurate total pressure loss can be obtained, which results in more credible net efficiency

  11. Preliminary neutronic design of high burnup OTTO cycle pebble bed reactor

    International Nuclear Information System (INIS)

    Setiadipura, T.; Zuhair; Irwanto, D.

    2015-01-01

    The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM) loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble. (author)

  12. Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

    Directory of Open Access Journals (Sweden)

    T. Setiadipura

    2015-04-01

    Full Text Available The pebble bed type High Temperature Gas-cooled Reactor (HTGR is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble

  13. Modeling transit bus fuel consumption on the basis of cycle properties.

    Science.gov (United States)

    Delgado, Oscar F; Clark, Nigel N; Thompson, Gregory J

    2011-04-01

    A method exists to predict heavy-duty vehicle fuel economy and emissions over an "unseen" cycle or during unseen on-road activity on the basis of fuel consumption and emissions data from measured chassis dynamometer test cycles and properties (statistical parameters) of those cycles. No regression is required for the method, which relies solely on the linear association of vehicle performance with cycle properties. This method has been advanced and examined using previously published heavy-duty truck data gathered using the West Virginia University heavy-duty chassis dynamometer with the trucks exercised over limited test cycles. In this study, data were available from a Washington Metropolitan Area Transit Authority emission testing program conducted in 2006. Chassis dynamometer data from two conventional diesel buses, two compressed natural gas buses, and one hybrid diesel bus were evaluated using an expanded driving cycle set of 16 or 17 different driving cycles. Cycle properties and vehicle fuel consumption measurements from three baseline cycles were selected to generate a linear model and then to predict unseen fuel consumption over the remaining 13 or 14 cycles. Average velocity, average positive acceleration, and number of stops per distance were found to be the desired cycle properties for use in the model. The methodology allowed for the prediction of fuel consumption with an average error of 8.5% from vehicles operating on a diverse set of chassis dynamometer cycles on the basis of relatively few experimental measurements. It was found that the data used for prediction should be acquired from a set that must include an idle cycle along with a relatively slow transient cycle and a relatively high speed cycle. The method was also applied to oxides of nitrogen prediction and was found to have less predictive capability than for fuel consumption with an average error of 20.4%.

  14. Replication of Annual Cycles in Mn in Hudson River Cores: Mn Peaks During High Water Flow

    Science.gov (United States)

    Abbott, D. H.; Hutson, D.; Marrero, A. M.; Block, K. A.; Chang, C.; Cai, Y.

    2017-12-01

    Using the results from an ITRAX, XRF scanner, we previously reported apparent annual cycles in Mn in a single, high sedimentation rate Hudson River core, LWB1-8, taken off Yonkers, NY (Carlson et al., 2016). We replicated these results in three more high sedimentation rate cores and found stratigraphic markers that verify our inferences about the annual nature of the Mn cycles. The three new cores are LWB4-5 taken off Peekskill, NY, and LWB3-44 and LWB3-25, both taken in Haverstraw Bay. The cores are from water depths of 7-9 meters and all have high magnetic susceptibilities (typically > 30 cgs units) in their upper 1 to 2 meters. The high susceptibilities are primarily produced by magnetite from modern industrial combustion. One core, LWB1-8, has reconnaissance Cs dates that verify the annual nature of the cycles. More Cs dates are expected before the meeting. We developed several new methods of verifying the annual nature of our layer counts. The first is looking at the grain size distribution and age of layers with unusually high Mn peaks. Peaks in Si, Ni and Ti and peaks in percentage of coarse material typically accompany the peaks in Mn. Some are visible as yellow sandy layers. The five highest peaks in Mn in LWB1-8 have layer counted ages that correspond (within 1 year in the top meter and within 2 years in the bottom meter) to 1996, 1948, 1913, 1857 and 1790. The latter three events are the three largest historical spring freshets on the Hudson. 1996 is a year of unusually high flow rate during the spring freshet. Based on our work and previous work on Mn cycling in rivers, we infer that the peaks in Mn are produced by extreme erosional events that erode sediment and release pore water Mn into the water column. The other methods of testing our chronology involve marine storms that increase Ca and Sr and a search for fragments of the Peekskill meteorite that fell in October 1992. More information on the latter will be available by the meeting.

  15. High-response intrauterine insemination cycles converted to low-cost in vitro fertilization

    Directory of Open Access Journals (Sweden)

    Aletebi F

    2011-05-01

    Full Text Available Fatma AletebiAssisted Reproduction Unit, Department of Obstetrics and Gynaecology, King Abdulaziz University, Soliman Fakeeh Hospital, Jeddah, Saudi ArabiaBackground: There is a trend to cancel intrauterine insemination (IUI in women with a high response. The aim of this study was to evaluate the efficacy of low-cost in vitro fertilization (IVF in high-response IUI cycles in comparison with conventional IVF.Methods and materials: A total of 46 women were included in the study. Group A (study group included 23 women with hyper-response to IUI cycles who were converted to IVF. They received oral letrozole 2.5 mg twice daily from days 3–7 of the menstrual cycle, along with 75 International Units (IU of recombinant follicle-stimulating hormone on days 3 and 8. Group B (control group underwent conventional IVF, and received downregulation with a gonadotrophin-releasing hormone agonist followed by stimulation with recombinant follicle-stimulating hormone 150–300 IU/day. Ovulation was triggered by 10,000 IU of human chorionic gonadotrophin, followed by IVF and embryo transfer. The primary outcome measure analyzed was pregnancy rates in both groups.Results: The study group received a significantly lower (P = 0.001 total dose of follicle-stimulating hormone and had significantly (P = 0.002 decreased levels of terminal estradiol. Although the pregnancy rate (30.43% in the study group versus 39.13% in the conventional group per stimulated cycle was higher in the conventional IVF group, the miscarriage rate (study group 4.34% versus conventional group 13.04% was also higher, and hence the take-home baby rate (study group 26.08% versus conventional group 30.43% was more or less similar in both the groups.Conclusion: IVF can be offered to women having a high response to IUI cycles with good pregnancy rates and at low cost compared with use of a conventional protocol, and therefore can be considered more patient-friendly in selected cases.Keywords: low

  16. In situ observation of high temperature tensile deformation and low cycle fatigue response in a nickel-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xudong, E-mail: lxdong0700@hotmail.com; Du, Jinhui; Deng, Qun

    2013-12-20

    High temperature tension and low cycle fatigue experiments of IN718 alloy have been performed in the electro-hydraulic servo system with scanning electron microscope at 455 °C. Fatigue crack initiation and propagation process are investigated in situ. Results show that the carbide and twin grain are the crack source of the low cycle fatigue of IN718 alloy, and the low cycle fatigue life of the alloy increases with the decrease in grain size.

  17. Fuel cycles with high fuel burn-up: analysis of reactivity coefficients

    International Nuclear Information System (INIS)

    Kryuchkov, E.F.; Shmelev, A.N.; Ternovykh, M.J.; Tikhomirov, G.V.; Jinhong, L.; Saito, M.

    2003-01-01

    Fuel cycles of light-water reactors (LWR) with high fuel burn-up (above 100 MWd/kg), as a rule, involve large amounts of fissionable materials. It leads to forming the neutron spectrum harder than that in traditional LWR. Change of neutron spectrum and significant amount of non-traditional isotopes (for example, 237 Np, 238 Pu, 231 Pa, 232 U) in such fuel compositions can alter substantially reactivity coefficients as compared with traditional uranium-based fuel. The present work addresses the fuel cycles with high fuel burn-up which are based on Th-Pa-U and U-Np-Pu fuel compositions. Numerical analyses are carried out to determine effective neutron multiplication factor and void reactivity coefficient (VRC) for different values of fuel burn-up and different lattice parameters. The algorithm is proposed for analysis of isotopes contribution to these coefficients. Various ways are considered to upgrade safety of nuclear fuel cycles with high fuel burn-up. So, the results obtained in this study have demonstrated that: -1) Non-traditional fuel compositions developed for achievement of high fuel burn-up in LWR can possess positive values of reactivity coefficients that is unacceptable from the reactor operation safety point of view; -2) The lattice pitch of traditional LWR is not optimal for non-traditional fuel compositions, the increased value of the lattice pitch leads to larger value of initial reactivity margin and provides negative VRC within sufficiently broad range of coolant density; -3) Fuel burn-up has an insignificant effect on VRC dependence on coolant density, so, the measures undertaken to suppress positive VRC of fresh fuel will be effective for partially burnt-up fuel compositions also and; -4) Increase of LWR core height and introduction of additional moderators into the fuel lattice can be used as the ways to reach negative VRC values for full range of possible coolant density variations

  18. Fuel cycles with high fuel burn-up: analysis of reactivity coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Kryuchkov, E.F.; Shmelev, A.N.; Ternovykh, M.J.; Tikhomirov, G.V.; Jinhong, L. [Moscow Engineering Physics Institute (State University) (Russian Federation); Saito, M. [Tokyo Institute of Technology (Japan)

    2003-07-01

    Fuel cycles of light-water reactors (LWR) with high fuel burn-up (above 100 MWd/kg), as a rule, involve large amounts of fissionable materials. It leads to forming the neutron spectrum harder than that in traditional LWR. Change of neutron spectrum and significant amount of non-traditional isotopes (for example, {sup 237}Np, {sup 238}Pu, {sup 231}Pa, {sup 232}U) in such fuel compositions can alter substantially reactivity coefficients as compared with traditional uranium-based fuel. The present work addresses the fuel cycles with high fuel burn-up which are based on Th-Pa-U and U-Np-Pu fuel compositions. Numerical analyses are carried out to determine effective neutron multiplication factor and void reactivity coefficient (VRC) for different values of fuel burn-up and different lattice parameters. The algorithm is proposed for analysis of isotopes contribution to these coefficients. Various ways are considered to upgrade safety of nuclear fuel cycles with high fuel burn-up. So, the results obtained in this study have demonstrated that: -1) Non-traditional fuel compositions developed for achievement of high fuel burn-up in LWR can possess positive values of reactivity coefficients that is unacceptable from the reactor operation safety point of view; -2) The lattice pitch of traditional LWR is not optimal for non-traditional fuel compositions, the increased value of the lattice pitch leads to larger value of initial reactivity margin and provides negative VRC within sufficiently broad range of coolant density; -3) Fuel burn-up has an insignificant effect on VRC dependence on coolant density, so, the measures undertaken to suppress positive VRC of fresh fuel will be effective for partially burnt-up fuel compositions also and; -4) Increase of LWR core height and introduction of additional moderators into the fuel lattice can be used as the ways to reach negative VRC values for full range of possible coolant density variations.

  19. Surface-finish effects on the high-cycle fatigue of Alloy 718

    International Nuclear Information System (INIS)

    Korth, G.E.

    1981-06-01

    Alloy 718 us a precipitation-hardening nickel-base superalloy that is being specified for various components for liquid-meal fast breeder reactors (LMFBRs). This alloy maintains high strength at elevated temperatures making it a desirable structural material. But the property that justifies most LMFBR applications is the alloy's resistance to thermal striping damage due to its high fatigue endurance strength. Thermal striping is a high-cycle fatigue phenomenon caused by thermal stresses from the fluctuating mixing action of sodium streams of differing temperatures impinging on the metal surfaces. Most of the design data is generated from laboratory fatigue specimens with carefully controlled surface finishes prepared with a low-stress grind and buffed to a surface finish 8--12 in. Since Alloy 718 has been shown to be quite notch sensitive under cyclic loading, the detrimental effect on the high-cycle fatigue properties caused by shop surface finishes of actual components has been questioned. This report examines some of the surface finishes that could be produced in a commercial shop on an actual component

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

    Science.gov (United States)

    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.

  1. Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland

    DEFF Research Database (Denmark)

    Turconi, Roberto; O'Dwyer, C.; Flynn, D.

    2014-01-01

    demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations...... significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11% reduction. Given that production technologies are typically modeled assuming steady-state operation at full load...

  2. WESF cesium capsule behavior at high temperature or during thermal cycling

    International Nuclear Information System (INIS)

    Tingey, G.L.; Gray, W.J.; Shippell, R.J.; Katayama, Y.B.

    1985-06-01

    Double-walled stainless steel (SS) capsules prepared for storage of radioactive 137 Cs from defense waste are now being considered for use as sources for commercial irradiation. Cesium was recovered at B-plant from the high-level radioactive waste generated during processing of defense nuclear fuel. It was then purified, converted to the chloride form, and encapsulated at the Hanford Waste Encapsulation and Storage Facility (WESF). The molten cesium chloride salt was encapsulated by pouring it into the inner of two concentric SS cylinders. Each cylinder was fitted with a SS end cap that was welded in place by inert gas-tungsten arc welding. The capsule configuration and dimensions are shown in Figure 1. In a recent review of the safety of these capsules, Tingey, Wheelwright, and Lytle (1984) indicated that experimental studies were continuing to produce long-term corrosion data, to reaffirm capsule integrity during a 90-min fire where capsule temperatures reached 800 0 C, to monitor mechanical properties as a function of time, and to assess the effects of thermal cycling due to periodic transfer of the capsules from a water storage pool to the air environment of an irradiator facility. This report covers results from tests that simulated the effects of the 90-min fire and from thermal cycling actual WESF cesium capsules for 3845 cycles over a period of six months. 11 refs., 39 figs., 9 tabs

  3. The role of high cycle fatigue (HCF) onset in Francis runner reliability

    International Nuclear Information System (INIS)

    Gagnon, M; Tahan, S A; Bocher, P; Thibault, D

    2012-01-01

    High Cycle Fatigue (HCF) plays an important role in Francis runner reliability. This paper presents a model in which reliability is defined as the probability of not exceeding a threshold above which HCF contributes to crack propagation. In the context of combined Low Cycle Fatigue (LCF) and HCF loading, the Kitagawa diagram is used as the limit state threshold for reliability. The reliability problem is solved using First-Order Reliability Methods (FORM). A study case is proposed using in situ measured strains and operational data. All the parameters of the reliability problem are based either on observed data or on typical design specifications. From the results obtained, we observed that the uncertainty around the defect size and the HCF stress range play an important role in reliability. At the same time, we observed that expected values for the LCF stress range and the number of LCF cycles have a significant influence on life assessment, but the uncertainty around these values could be neglected in the reliability assessment.

  4. Why is solar cycle 24 an inefficient producer of high-energy particle events?

    Science.gov (United States)

    Vainio, Rami; Raukunen, Osku; Tylka, Allan J.; Dietrich, William F.; Afanasiev, Alexandr

    2017-08-01

    Aims: The aim of the study is to investigate the reason for the low productivity of high-energy SEPs in the present solar cycle. Methods: We employ scaling laws derived from diffusive shock acceleration theory and simulation studies including proton-generated upstream Alfvén waves to find out how the changes observed in the long-term average properties of the erupting and ambient coronal and/or solar wind plasma would affect the ability of shocks to accelerate particles to the highest energies. Results: Provided that self-generated turbulence dominates particle transport around coronal shocks, it is found that the most crucial factors controlling the diffusive shock acceleration process are the number density of seed particles and the plasma density of the ambient medium. Assuming that suprathermal populations provide a fraction of the particles injected to shock acceleration in the corona, we show that the lack of most energetic particle events as well as the lack of low charge-to-mass ratio ion species in the present cycle can be understood as a result of the reduction of average coronal plasma and suprathermal densities in the present cycle over the previous one.

  5. Neutronic behavior of thorium fuel cycles in a very high temperature hybrid system

    International Nuclear Information System (INIS)

    Rodriguez Garcia, Lorena; Milian Perez, Daniel; Garcia Hernandez, Carlos; Milian Lorenzo, Daniel; Velasco, Abanades

    2013-01-01

    Nuclear energy needs to guarantee four important issues to be successful as a sustainable energy source: nuclear safety, economic competitiveness, proliferation resistance and a minimal production of radioactive waste. Pebble bed reactors (PBR), which are very high temperature systems together with fuel cycles based in Thorium, they could offer the opportunity to meet the sustainability demands. Thorium is a potentially valuable energy source since it is about three to four times as abundant as Uranium. It is also a widely distributed natural resource readily accessible in many countries. This paper shows the main advantages of the use of a hybrid system formed by a Pebble Bed critical nuclear reactor and two Pebble Bed Accelerator Driven Systems (ADSs) using a variety of fuel cycles with Thorium (Th+U 233 , Th+Pu 239 and Th+U). The parameters related to the neutronic behavior like deep burn, nuclear fuel breeding, Minor Actinide stockpile, power density profiles and other are used to compare the fuel cycles using the well-known MCNPX computational code. (author)

  6. Thorium-Based Fuel Cycles in the Modular High Temperature Reactor

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong; YANG Yongwei; JING Xingqing; XU Yunlin

    2006-01-01

    Large stockpiles of civil-grade as well as weapons-grade plutonium have been accumulated in the world from nuclear power or other programs of different countries. One alternative for the management of the plutonium is to incinerate it in the high temperature reactor (HTR). The thorium-based fuel cycle was studied in the modular HTR to reduce weapons-grade plutonium stockpiles, while producing no additional plutonium or other transuranic elements. Three thorium-uranium fuel cycles were also investigated. The thorium absorption cross sections of the resolved and unresolved resonances were generated using the ZUT-DGL code based on existing resonance data. The equilibrium core of the modular HTR was calculated and analyzed by means of the code VSOP'94. The results show that the modular HTR can incinerate most of the initially loaded plutonium amounting to about 95.3% net 239Pu for weapons-grade plutonium and can effectively utilize the uranium and thorium in the thorium-uranium fuel cycles.

  7. Uranium-thorium fuel cycle in a very high temperature hybrid system

    International Nuclear Information System (INIS)

    Hernandez, C.R.G.; Oliva, A.M.; Fajardo, L.G.; Garcia, J.A.R.; Curbelo, J.P.; Abadanes, A.

    2011-01-01

    Thorium is a potentially valuable energy source since it is about three to four times as abundant as Uranium. It is also a widely distributed natural resource readily accessible in many countries. Therefore, Thorium fuels can complement Uranium fuels and ensure long term sustainability of nuclear power. The main advantages of the use of a hybrid system formed by a Pebble Bed critical nuclear reactor and two Pebble Bed Accelerator Driven Systems (ADSs) using a Uranium-Thorium (U + Th) fuel cycle are shown in this paper. Once-through and two step U + Th fuel cycle was evaluated. With this goal, a preliminary conceptual design of a hybrid system formed by a Graphite Moderated Gas-Cooled Very High Temperature Reactor and two ADSs is proposed. The main parameters related to the neutronic behavior of the system in a deep burn scheme are optimized. The parameters that describe the nuclear fuel breeding and Minor Actinide stockpile are compared with those of a simple Uranium fuel cycle. (author)

  8. Effect of grain size on high temperature low-cycle fatigue properties of inconel 617

    International Nuclear Information System (INIS)

    Hattori, Hiroshi; Kitagawa, Masaki; Ohtomo, Akira

    1982-01-01

    The effect of grain size on the high temperature low-cycle fatigue behavior and other material strength properties of Inconel 617 was studied at 1 273 K in air. The strain controlled low-cycle fatigue tests were conducted with a symmetrical (FF type) and an asymmetrical (SF type) strain wave forms. The latter wave form was used for the evaluation of creep-fatigue interaction. The main results obtained in this study are as follows: 1) The tensile strength slightly increased with the increase of the grain diameter. On the other hand, the tensile ductility remarkabley decreased with the increase of the grain diameter. 2) The creep rupture life remarkabley increased with the increase of the grain diameter, especially at the lower stress levels. The effect of grain size on creep ductility has not detailed. 3) The low-cycle fatigue life remarkably decreased with the increase of the grain diameter, especially at the lower strain ranges. 4) The creep-fatigue life was less sensitive to the grain diameter than the fatigue life, because the grain size effects on creep and on fatigue were contrary. It is seemed that the creep-fatigue life is determined by the proportion of the creep and fatigue contribution. 5) The fatigue and creep-fatigue test results have good relations with the tensile and creep ductilities at the test temperature. (author)

  9. Neutronic behavior of thorium fuel cycles in a very high temperature hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Garcia, Lorena; Milian Perez, Daniel; Garcia Hernandez, Carlos; Milian Lorenzo, Daniel, E-mail: dperez@instec.cu, E-mail: cgh@instec.cu, E-mail: dmilian@instec.cu [Higher Institute of Technologies and Applied Sciences, Havana (Cuba); Velasco, Abanades, E-mail: abanades@etsii.upm.es [Department of Simulation of Thermo Energy Systems, Polytechnic University of Madrid (Spain)

    2013-07-01

    Nuclear energy needs to guarantee four important issues to be successful as a sustainable energy source: nuclear safety, economic competitiveness, proliferation resistance and a minimal production of radioactive waste. Pebble bed reactors (PBR), which are very high temperature systems together with fuel cycles based in Thorium, they could offer the opportunity to meet the sustainability demands. Thorium is a potentially valuable energy source since it is about three to four times as abundant as Uranium. It is also a widely distributed natural resource readily accessible in many countries. This paper shows the main advantages of the use of a hybrid system formed by a Pebble Bed critical nuclear reactor and two Pebble Bed Accelerator Driven Systems (ADSs) using a variety of fuel cycles with Thorium (Th+U{sup 233}, Th+Pu{sup 239} and Th+U). The parameters related to the neutronic behavior like deep burn, nuclear fuel breeding, Minor Actinide stockpile, power density profiles and other are used to compare the fuel cycles using the well-known MCNPX computational code. (author)

  10. Hybrid Life Cycle Assessment of Low, Mid and High-Rise Multi-Family Dwellings

    Directory of Open Access Journals (Sweden)

    Kimberly Bawden

    2015-04-01

    Full Text Available We undertake Life Cycle Assessment (LCA of the cumulative energy demand (CED and global warming potential (GWP for a portfolio of 10 multi-family residences in the U.S. We argue that prior LCA studies of buildings use an inconsistent boundary for processes to be included in the supply chain: The operational phase includes all energy use in a building, but supply chains for the production of appliances, equipment and consumables associated with activities done in the building are neglected. We correct this by starting the analysis with an explicit definition of a functional unit, providing climate controlled space, and including processes associated with this functional unit. Using a hybrid LCA approach, the CED for low, mid and high-rise multi-family residences is found to increase from 30, 34, to 39 GJ/m2, respectively. This increase is due to the need for energy-intensive structural materials such as concrete and steel in taller buildings. With our approach, the share of materials and construction of total life cycle energy doubles to 26%, compared with a 13% share that would be obtained with inconsistent system boundaries used in prior studies. We thus argue that explicit definition of functional unit leads to an increase in the contribution of supply chains to building energy life cycles.

  11. Molecular Materials for Nonaqueous Flow Batteries with a High Coulombic Efficiency and Stable Cycling.

    Science.gov (United States)

    Milton, Margarita; Cheng, Qian; Yang, Yuan; Nuckolls, Colin; Hernández Sánchez, Raúl; Sisto, Thomas J

    2017-12-13

    This manuscript presents a working redox battery in organic media that possesses remarkable cycling stability. The redox molecules have a solubility over 1 mol electrons/liter, and a cell with 0.4 M electron concentration is demonstrated with steady performance >450 cycles (>74 days). Such a concentration is among the highest values reported in redox flow batteries with organic electrolytes. The average Coulombic efficiency of this cell during cycling is 99.868%. The stability of the cell approaches the level necessary for a long lifetime nonaqueous redox flow battery. For the membrane, we employ a low cost size exclusion cellulose membrane. With this membrane, we couple the preparation of nanoscale macromolecular electrolytes to successfully avoid active material crossover. We show that this cellulose-based membrane can support high voltages in excess of 3 V and extreme temperatures (-20 to 110 °C). These extremes in temperature and voltage are not possible with aqueous systems. Most importantly, the nanoscale macromolecular platforms we present here for our electrolytes can be readily tuned through derivatization to realize the promise of organic redox flow batteries.

  12. Endurance, aerobic high-intensity, and repeated sprint cycling performance is unaffected by normobaric "Live High-Train Low"

    DEFF Research Database (Denmark)

    Bejder, Jacob; Andersen, Andreas Breenfeldt; Buchardt, Rie

    2017-01-01

    The aim was to investigate whether 6 weeks of normobaric "Live High-Train Low" (LHTL) using altitude tents affect highly trained athletes incremental peak power, 26-km time-trial cycling performance, 3-min all-out performance, and 30-s repeated sprint ability. In a double-blinded, placebo......-controlled cross-over design, seven highly trained triathletes were exposed to 6 weeks of normobaric hypoxia (LHTL) and normoxia (placebo) for 8 h/day. LHTL exposure consisted of 2 weeks at 2500 m, 2 weeks at 3000 m, and 2 weeks at 3500 m. Power output during an incremental test, ~26-km time trial, 3-min all...... conducted in a double-blinded, placebo-controlled cross-over design do not affect power output during an incremental test, a ~26-km time-trial test, or 3-min all-out exercise in highly trained triathletes. Furthermore, 30 s of repeated sprint ability was unaltered....

  13. Experimental investigation of crack initiation in face-centered cubic materials in the high and very high cycle fatigue regime

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Thomas

    2016-07-01

    Materials in many modern small-scale applications are under complex cyclic stress states and undergo up to 10{sup 9} cycles. Fatigue mechanisms limit their lifetime and lead to failure. Therefore, the Very High Cycle Fatigue (VHCF) regime needs to be studied. This thesis investigates the fatigue mechanisms and crack initiation of nickel, aluminum and copper on a small-scale in the VHCF regime by means of innovative fatigue experimentation. Firstly, the development and implementation of a novel custom-built resonant fatigue setup showed that the resonant frequency of bending micro-samples changes with increasing cycle number due to the accumulating fatigue damage. Then, additional insights on early damage formation have been explored. Mechanisms, prior to crack initiation, such as slip band formation at a state where it appears in only a few grains, have been observed. Cyclic hardening, vacancy formation and oxidation formation may be considered as possible explanations for early fatigue mechanisms. In addition, the new experimental setup can be used to define parameters needed for crack initiation models. Finally, these crack initiation processes have been experimentally examined for pure aluminum and pure copper.

  14. Nitrogen cycling responses to mountain pine beetle disturbance in a high elevation whitebark pine ecosystem.

    Science.gov (United States)

    Keville, Megan P; Reed, Sasha C; Cleveland, Cory C

    2013-01-01

    Ecological disturbances can significantly affect biogeochemical cycles in terrestrial ecosystems, but the biogeochemical consequences of the extensive mountain pine beetle outbreak in high elevation whitebark pine (WbP) (Pinus albicaulis) ecosystems of western North America have not been previously investigated. Mountain pine beetle attack has driven widespread WbP mortality, which could drive shifts in both the pools and fluxes of nitrogen (N) within these ecosystems. Because N availability can limit forest regrowth, understanding how beetle-induced mortality affects N cycling in WbP stands may be critical to understanding the trajectory of ecosystem recovery. Thus, we measured above- and belowground N pools and fluxes for trees representing three different times since beetle attack, including unattacked trees. Litterfall N inputs were more than ten times higher under recently attacked trees compared to unattacked trees. Soil inorganic N concentrations also increased following beetle attack, potentially driven by a more than two-fold increase in ammonium (NH₄⁺) concentrations in the surface soil organic horizon. However, there were no significant differences in mineral soil inorganic N or soil microbial biomass N concentrations between attacked and unattacked trees, implying that short-term changes in N cycling in response to the initial stages of WbP attack were restricted to the organic horizon. Our results suggest that while mountain pine beetle attack drives a pulse of N from the canopy to the forest floor, changes in litterfall quality and quantity do not have profound effects on soil biogeochemical cycling, at least in the short-term. However, continuous observation of these important ecosystems will be crucial to determining the long-term biogeochemical effects of mountain pine beetle outbreaks.

  15. Initial high anti-emetic efficacy of granisetron with dexamethasone is not maintained over repeated cycles.

    Science.gov (United States)

    de Wit, R.; van den Berg, H.; Burghouts, J.; Nortier, J.; Slee, P.; Rodenburg, C.; Keizer, J.; Fonteyn, M.; Verweij, J.; Wils, J.

    1998-01-01

    We have reported previously that the anti-emetic efficacy of single agent 5HT3 antagonists is not maintained when analysed with the measurement of cumulative probabilities. Presently, the most effective anti-emetic regimen is a combination of a 5HT3 antagonist plus dexamethasone. We, therefore, assessed the sustainment of efficacy of such a combination in 125 patients, scheduled to receive cisplatin > or = 70 mg m(-2) either alone or in combination with other cytotoxic drugs. Anti-emetic therapy was initiated with 10 mg of dexamethasone and 3 mg of granisetron intravenously, before cisplatin. On days 1-6, patients received 8 mg of dexamethasone and 1 mg of granisetron twice daily by oral administration. Protection was assessed during all cycles and calculated based on cumulative probability analyses using the method of Kaplan-Meier and a model for transitional probabilities. Irrespective of the type of analysis used, the anti-emetic efficacy of granisetron/dexamethasone decreased over cycles. The initial complete acute emesis protection rate of 66% decreased to 30% according to the method of Kaplan-Meier and to 39% using the model for transitional probabilities. For delayed emesis, the initial complete protection rate of 52% decreased to 21% (Kaplan-Meier) and to 43% (transitional probabilities). In addition, we observed that protection failure in the delayed emesis period adversely influenced the acute emesis protection in the next cycle. We conclude that the anti-emetic efficacy of a 5HT3 antagonist plus dexamethasone is not maintained over multiple cycles of highly emetogenic chemotherapy, and that the acute emesis protection is adversely influenced by protection failure in the delayed emesis phase. PMID:9652766

  16. Nitrogen cycling responses to mountain pine beetle disturbance in a high elevation whitebark pine ecosystem

    Science.gov (United States)

    Keville, Megan P.; Reed, Sasha C.; Cleveland, Cory C.

    2013-01-01

    Ecological disturbances can significantly affect biogeochemical cycles in terrestrial ecosystems, but the biogeochemical consequences of the extensive mountain pine beetle outbreak in high elevation whitebark pine (WbP) (Pinus albicaulis) ecosystems of western North America have not been previously investigated. Mountain pine beetle attack has driven widespread WbP mortality, which could drive shifts in both the pools and fluxes of nitrogen (N) within these ecosystems. Because N availability can limit forest regrowth, understanding how beetle-induced mortality affects N cycling in WbP stands may be critical to understanding the trajectory of ecosystem recovery. Thus, we measured above- and belowground N pools and fluxes for trees representing three different times since beetle attack, including unattacked trees. Litterfall N inputs were more than ten times higher under recently attacked trees compared to unattacked trees. Soil inorganic N concentrations also increased following beetle attack, potentially driven by a more than two-fold increase in ammonium (NH4+) concentrations in the surface soil organic horizon. However, there were no significant differences in mineral soil inorganic N or soil microbial biomass N concentrations between attacked and unattacked trees, implying that short-term changes in N cycling in response to the initial stages of WbP attack were restricted to the organic horizon. Our results suggest that while mountain pine beetle attack drives a pulse of N from the canopy to the forest floor, changes in litterfall quality and quantity do not have profound effects on soil biogeochemical cycling, at least in the short-term. However, continuous observation of these important ecosystems will be crucial to determining the long-term biogeochemical effects of mountain pine beetle outbreaks.

  17. Life cycle assessment of Mexican polymer and high-durability cotton paper banknotes.

    Science.gov (United States)

    Luján-Ornelas, Cristina; Mancebo Del C Sternenfels, Uriel; Güereca, Leonor Patricia

    2018-02-23

    This study compares the environmental performance of Mexican banknotes printed on high-durability cotton paper (HD paper) and thermoplastic polymer (polymer) through a life cycle assessment to appraise the environmental impacts from the extraction of raw materials to the final disposal of the banknotes. The functional unit was defined considering the next parameters: 1) lifespan of the banknotes, stablished in 31.5 and 54months for HD paper and polymer, respectively; 2) denomination, selecting $200 pesos banknotes; 3) a 5year time frame and 4) a defined amount of money, in this case stablished as the monthly cash supply of an average Mexican household, equaling $12,708 pesos. Accordingly, 121 pieces for the HD paper and 71 pieces for the polymer banknotes were analyzed. The results favor the banknotes printed on polymer substrate primarily because of the longer lifespan of this type of material; however, there is a considerable environmental impact in the stages of distribution, followed by the extraction of the raw materials (crude oil) during manufacturing. Regarding the HD cotton paper, the major impact corresponds to extraction of the raw materials, followed by the distribution of the banknotes. The inclusion of the automatic teller machines (ATMs) in the life cycle assessment of banknotes shows that the electricity required by these devices became the largest contributor to the environmental impacts. Additionally, the sensitivity analysis that the average lifetime of the banknotes is a determining factor for the environmental impacts associated with the whole life cycle of this product. The life cycle stages that refer to the extraction of the raw materials, combined with the average lifetime of the banknotes and the electricity required during the usage stage, are determining factors in the total environmental impact associated with Mexican banknotes. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Few-cycle high energy mid-infrared pulse from Ho:YLF laser

    International Nuclear Information System (INIS)

    Murari, Krishna

    2017-04-01

    Over the past decade, development of high-energy ultrafast laser sources has led to important breakthroughs in attoscience and strong-field physics study in atoms and molecules. Coherent pulse synthesis of few-cycle high-energy laser pulse is a promising tool to generate isolated attosecond pulses via high harmonics generation (HHG). An effective way to extend the HHG cut-off energy to higher values is making use of long mid-infrared (MIR) driver wavelength, as the ponderomotive potential scales quadratically with wavelength. If properly scaled in energy to multi-mJ level and few-cycle duration, such pulses provide a direct path to intriguing attoscience experiments in gases and solids, which even permit the realization of bright coherent table-top HHG sources in the water-window and keV X-ray region. However, the generation of high-intensity long-wavelength MIR pulses has always remained challenging, in particular starting from high-energy picosecond 2-μm laser driver, that is suitable for further energy scaling of the MIR pulses to multi-mJ energies by utilizing optical parametric amplifiers (OPAs). In this thesis, a front-end source for such MIR OPA is presented. In particular, a novel and robust strong-field few-cycle 2-μm laser driver directly from picosecond Ho:YLF laser and utilizing Kagome fiber based compression is presented. We achieved: a 70-fold compression of 140-μJ, 3.3-ps pulses from Ho:YLF amplifier to 48 fs with 11 μJ energy. The work presented in this thesis demonstrates a straightforward path towards generation of few-cycle MIR pulses and we believe that in the future the ultrafast community will benefit from this enabling technology. The results are summarized in mainly four parts: The first part is focused on the development of a 2-μm, high-energy laser source as the front-end. Comparison of available technology in general and promising gain media at MIR wavelength are discussed. Starting from the basics of an OPA, the design criteria

  19. Few-cycle high energy mid-infrared pulse from Ho:YLF laser

    Energy Technology Data Exchange (ETDEWEB)

    Murari, Krishna

    2017-04-15

    Over the past decade, development of high-energy ultrafast laser sources has led to important breakthroughs in attoscience and strong-field physics study in atoms and molecules. Coherent pulse synthesis of few-cycle high-energy laser pulse is a promising tool to generate isolated attosecond pulses via high harmonics generation (HHG). An effective way to extend the HHG cut-off energy to higher values is making use of long mid-infrared (MIR) driver wavelength, as the ponderomotive potential scales quadratically with wavelength. If properly scaled in energy to multi-mJ level and few-cycle duration, such pulses provide a direct path to intriguing attoscience experiments in gases and solids, which even permit the realization of bright coherent table-top HHG sources in the water-window and keV X-ray region. However, the generation of high-intensity long-wavelength MIR pulses has always remained challenging, in particular starting from high-energy picosecond 2-μm laser driver, that is suitable for further energy scaling of the MIR pulses to multi-mJ energies by utilizing optical parametric amplifiers (OPAs). In this thesis, a front-end source for such MIR OPA is presented. In particular, a novel and robust strong-field few-cycle 2-μm laser driver directly from picosecond Ho:YLF laser and utilizing Kagome fiber based compression is presented. We achieved: a 70-fold compression of 140-μJ, 3.3-ps pulses from Ho:YLF amplifier to 48 fs with 11 μJ energy. The work presented in this thesis demonstrates a straightforward path towards generation of few-cycle MIR pulses and we believe that in the future the ultrafast community will benefit from this enabling technology. The results are summarized in mainly four parts: The first part is focused on the development of a 2-μm, high-energy laser source as the front-end. Comparison of available technology in general and promising gain media at MIR wavelength are discussed. Starting from the basics of an OPA, the design criteria

  20. WLTP Random Cycle Generator

    NARCIS (Netherlands)

    Kooijman, D.G.; Balau, A.E.; Wilkins, S.; Ligterink, N.; Cuelenaere, R.

    2015-01-01

    European light duty vehicle emission legislation is gradually shifting the focus from test procedures with merely static test cycles, towards procedures including Real Driving Emissions (RDE), as they are a mean to achieve the European (NOx) emission reduction target. Hence a RDE trip must represent

  1. WLTP random cycle generator

    NARCIS (Netherlands)

    Kooijman, D.G.; Balau, A.E.; Wilkins, S.; Ligterink, N.; Cuelenaere, R.

    2015-01-01

    European light duty vehicle emission legislation is gradually shifting the focus from test procedures with merely static test cycles, towards procedures including Real Driving Emissions (RDE), as they are a mean to achieve the European (NOx) emission reduction target. Hence a RDE trip must represent

  2. Life-cycle assessment of high-speed rail: the case of California

    International Nuclear Information System (INIS)

    Chester, Mikhail; Horvath, Arpad

    2010-01-01

    The state of California is expected to have significant population growth in the next half-century resulting in additional passenger transportation demand. Planning for a high-speed rail system connecting San Diego, Los Angeles, San Francisco, and Sacramento as well as many population centers between is now underway. The considerable investment in California high-speed rail has been debated for some time and now includes the energy and environmental tradeoffs. The per-trip energy consumption, greenhouse gas emissions, and other emissions are often compared against the alternatives (automobiles, heavy rail, and aircraft), but typically only considering vehicle operation. An environmental life-cycle assessment of the four modes was created to compare both direct effects of vehicle operation and indirect effects from vehicle, infrastructure, and fuel components. Energy consumption, greenhouse gas emissions, and SO 2 , CO, NO X , VOC, and PM 10 emissions were evaluated. The energy and emission intensities of each mode were normalized per passenger kilometer traveled by using high and low occupancies to illustrate the range in modal environmental performance at potential ridership levels. While high-speed rail has the potential to be the lowest energy consumer and greenhouse gas emitter, appropriate planning and continued investment would be needed to ensure sustained high occupancy. The time to environmental payback is discussed highlighting the ridership conditions where high-speed rail will or will not produce fewer environmental burdens than existing modes. Furthermore, environmental tradeoffs may occur. High-speed rail may lower energy consumption and greenhouse gas emissions per trip but can create more SO 2 emissions (given the current electricity mix) leading to environmental acidification and human health issues. The significance of life-cycle inventorying is discussed as well as the potential of increasing occupancy on mass transit modes.

  3. High-temperature reactors. Activities in France on the steam cycle HTR

    International Nuclear Information System (INIS)

    Lacoste Lareymondie, de; Guennec, N.; Rastoin, J.

    1975-01-01

    Although French activities cover all the possibilities of high-temperature reactors the effort of the last few years has been concentrated on the steam cycle electricity-generating version. This work, closely coordinated with that of General Atomic in application of agreements settled in 1972 and 1973, was devoted to engineering as a result of the assimilation of American technique by French industry and to research and development owing to the joint CEA and GA programme. After an examination of these two centers of activity the reasons which will lead to a closer collaboratin among the European partners of General Atomic are expressed in conclusion [fr

  4. Very high cycle fatigue crack initiation in electroplated Ni films under extreme stress gradients

    International Nuclear Information System (INIS)

    Baumert, E.K.; Pierron, O.N.

    2012-01-01

    A characterization technique based on kilohertz micro-resonators is presented to investigate the very high cycle fatigue behavior of 20 μm thick electroplated Ni films with a columnar microstructure (grain diameter less than 2 μm). The films exhibit superior fatigue resistance due to the extreme stress gradients at the surface. The effects of stress amplitude and environment on the formation of fatigue extrusions and micro-cracks are discussed based on scanning electron microscopy and the tracking of the specimens’ resonant frequency.

  5. Development of a high cycle vibration fatigue diagnostic system with non-contact vibration sensing

    International Nuclear Information System (INIS)

    Doi, So-myo; Nekomoto, Yoshitsugu; Takeishi, Masayuki; Miyoshi, Toshiaki; O'shima, Eiji

    1999-01-01

    In nuclear power plants, it is very important to foresee occurring events with in-operation -inspection (IOI) since the foreseeing makes plant maintenance more speedy and reliable. Moreover, information on plant condition under operating would make period of in-service inspection (ISI) shorter because maintenance plan can be made effectively using the information. In this study, a high cycle fatigue diagnostic system is being developed applying to especially pipe branches with small diameter under in-operating condition, which are in the radioactive areas of PWR plants and hard to access. This paper presents a concept of the in-operating diagnostic system and current status of developing sensing systems. (author)

  6. Generating power at high efficiency combined cycle technology for sustainable energy production

    CERN Document Server

    Jeffs, E

    2008-01-01

    Combined cycle technology is used to generate power at one of the highest levels of efficiency of conventional power plants. It does this through primary generation from a gas turbine coupled with secondary generation from a steam turbine powered by primary exhaust heat. Generating power at high efficiency thoroughly charts the development and implementation of this technology in power plants and looks to the future of the technology, noting the advantages of the most important technical features - including gas turbines, steam generator, combined heat and power and integrated gasification com

  7. Laser wakefield acceleration with high-power, few-cycle mid-IR lasers

    OpenAIRE

    Papp, Daniel; Wood, Jonathan C.; Gruson, Vincent; Bionta, Mina; Gruse, Jan-Niclas; Cormier, Eric; Najmudin, Zulfikar; Légaré, François; Kamperidis, Christos

    2018-01-01

    The study of laser wakefield electron acceleration (LWFA) using mid-IR laser drivers is a promising path for future laser driven electronaccelerators, when compared to traditional near-IR laser drivers uperating at 0.8-1 {\\mu}m central wavelength ({\\lambda}laser), as the necessary vector potential a_0 for electron injection can be achieved with smaller laser powers due to the linear dependence on {\\lambda}laser. In this work, we perform 2D PIC simulations on LWFA using few-cycle high power (5...

  8. Enhanced Cycling Stability of Rechargeable Li-O2 Batteries Using High Concentration Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin; Xu, Wu; Yan, Pengfei; Sun, Xiuliang; Bowden, Mark E.; Read, Jeffrey; Qian, Jiangfeng; Mei, Donghai; Wang, Chong M.; Zhang, Jiguang

    2016-01-26

    The electrolyte stability against reactive reduced-oxygen species is crucial for the development of rechargeable Li-O2 batteries. In this work, we systematically investigated the effect of lithium salt concentration in 1,2-dimethoxyethane (DME)-based electrolytes on the cycling stability of Li-O2 batteries. Cells with high concentration electrolyte illustrate largely enhanced cycling stability under both the full discharge/charge (2.0-4.5 V vs. Li/Li+) and the capacity limited (at 1,000 mAh g-1) conditions. These cells also exhibit much less reaction-residual on the charged air electrode surface, and much less corrosion to the Li metal anode. The density functional theory calculations are conducted on the molecular orbital energies of the electrolyte components and the Gibbs activation barriers for superoxide radical anion to attack DME solvent and Li+-(DME)n solvates. In a highly concentrated electrolyte, all DME molecules have been coordinated with salt and the C-H bond scission of a DME molecule becomes more difficult. Therefore, the decomposition of highly concentrated electrolyte in a Li-O2 battery can be mitigated and both air-cathodes and Li-metal anodes exhibits much better reversibility. As a results, the cyclability of Li-O2 can be largely improved.

  9. High-frequency oscillations in human and monkey neocortex during the wake-sleep cycle.

    Science.gov (United States)

    Le Van Quyen, Michel; Muller, Lyle E; Telenczuk, Bartosz; Halgren, Eric; Cash, Sydney; Hatsopoulos, Nicholas G; Dehghani, Nima; Destexhe, Alain

    2016-08-16

    Beta (β)- and gamma (γ)-oscillations are present in different cortical areas and are thought to be inhibition-driven, but it is not known if these properties also apply to γ-oscillations in humans. Here, we analyze such oscillations in high-density microelectrode array recordings in human and monkey during the wake-sleep cycle. In these recordings, units were classified as excitatory and inhibitory cells. We find that γ-oscillations in human and β-oscillations in monkey are characterized by a strong implication of inhibitory neurons, both in terms of their firing rate and their phasic firing with the oscillation cycle. The β- and γ-waves systematically propagate across the array, with similar velocities, during both wake and sleep. However, only in slow-wave sleep (SWS) β- and γ-oscillations are associated with highly coherent and functional interactions across several millimeters of the neocortex. This interaction is specifically pronounced between inhibitory cells. These results suggest that inhibitory cells are dominantly involved in the genesis of β- and γ-oscillations, as well as in the organization of their large-scale coherence in the awake and sleeping brain. The highest oscillation coherence found during SWS suggests that fast oscillations implement a highly coherent reactivation of wake patterns that may support memory consolidation during SWS.

  10. High-frequency oscillations in human and monkey neocortex during the wake–sleep cycle

    Science.gov (United States)

    Le Van Quyen, Michel; Muller, Lyle E.; Telenczuk, Bartosz; Halgren, Eric; Cash, Sydney; Hatsopoulos, Nicholas G.; Dehghani, Nima; Destexhe, Alain

    2016-01-01

    Beta (β)- and gamma (γ)-oscillations are present in different cortical areas and are thought to be inhibition-driven, but it is not known if these properties also apply to γ-oscillations in humans. Here, we analyze such oscillations in high-density microelectrode array recordings in human and monkey during the wake–sleep cycle. In these recordings, units were classified as excitatory and inhibitory cells. We find that γ-oscillations in human and β-oscillations in monkey are characterized by a strong implication of inhibitory neurons, both in terms of their firing rate and their phasic firing with the oscillation cycle. The β- and γ-waves systematically propagate across the array, with similar velocities, during both wake and sleep. However, only in slow-wave sleep (SWS) β- and γ-oscillations are associated with highly coherent and functional interactions across several millimeters of the neocortex. This interaction is specifically pronounced between inhibitory cells. These results suggest that inhibitory cells are dominantly involved in the genesis of β- and γ-oscillations, as well as in the organization of their large-scale coherence in the awake and sleeping brain. The highest oscillation coherence found during SWS suggests that fast oscillations implement a highly coherent reactivation of wake patterns that may support memory consolidation during SWS. PMID:27482084

  11. Control rod studies for alternative fuel cycles in the GA 1160 MW(e) high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Neef, H. J.

    1975-06-15

    The control system, which is investigated in this paper for both the low enriched uranium high enriched uranium/thorium fuel cycles, has been developed to control the General Atomics (GA) thorium fuel cycle 1160 MW(e) reactor. It has been shown in this investigation that its effectiveness in the low enriched and subsequent thorium cycle switch-over reactor is equivalent to the effectiveness in the thorium cycle. The shutdown margin in the low enriched core is even higher compared to the thorium core, mainly due to the presence of Pa-233 in the thorium cycle. As long as the fuel cycle for the thorium cycle is not closed with the recycling of U-233, the low enriched cycle will offer an attractive alternative. It was found that the GA 1160 MW(e) control system has enough built-in control rod capacity to accommodate the low enriched uranium cycle and to perform a later switch-over to a thorium-based fuel cycle.

  12. Optimization of advenced liquid natural gas-fuelled combined cycle machinery systems for a high-speed ferry

    DEFF Research Database (Denmark)

    Tveitaskog, Kari Anne; Haglind, Fredrik

    2012-01-01

    . Furthermore, practical and operational aspects of using these three machinery systems for a high-speed ferry are discussed. Two scenarios are evaluated. The first scenario evaluates the combined cycles with a given power requirement, optimizing the combined cycle while operating the gas turbine at part load...

  13. SCFR Fuel Cycles and Their Impact on the Performance of High-Level Waste Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Daisuke; Nogi, Naoyuki; Saito, Takumi [Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Nagasaki, Shinya [Nuclear Professional School, Graduate School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai, Ibaraki, 319-1188 (Japan)

    2009-06-15

    The concept of supercritical-pressure light water cooled fast reactor (SCFR) is developed and studied at the University of Tokyo. The impact of disposal of the waste generated in a fuel cycle with SCFR is also investigated in the project. It is of great interest how a fuel cycle with SCFR compares to the other fuel cycles from the back-end view point. With its various neutron spectrum, SCFR may be used to transmute both actinides and fission products. The objective of the present study is to evaluate and compare multiple fuel cycle designs in order to investigate the effects of SCFR and its transmutation capability upon the back-end risks. Three designs of fuel cycle are considered for evaluation in the present study. First, a simple fuel cycle with PWR and recycling is considered. The spent fuel from the PWR is reprocessed to recover uranium and plutonium, and the rest of the radioactive nuclides are vitrified and disposed of in a geologic repository. In the second design, the recovered uranium and plutonium in the reprocessing of PWR spent fuel is fabricated into a MOX fuel and irradiated in SCFR. The spent fuel from the SCFR is reprocessed to recover uranium and plutonium. In the third design, actinide elements are also separated from the PWR spent fuel and is loaded as the blanket fuel in SCFR core together with the MOX fuel fabricated from the recovered uranium and plutonium. In the same way as in the second design, the spent fuel from the SCFR is reprocessed to recover uranium and plutonium. In the second and the third designs, there are two streams of highly radioactive waste; one from the reprocessing (separation process) of the PWR spent fuel, and the other from the reprocessing of the SCFR spent fuel. Numerical codes Origen2.1 and SWAT is used for fuel irradiation calculation. The performance of the high-level radioactive waste repository is evaluated for each design of fuel cycle. It is assumed that the repository is located in a water-saturated geologic

  14. Fitness for duty

    International Nuclear Information System (INIS)

    Barnes, D.; Matney, C.

    1991-01-01

    A Fitness For Duty training program was developed to satisfy the requirements of the NRC, 10 CFR 26, 10 CFR 707 and to meet requirements at the Westinghouse Savannah River Company. Interactive videodisc technology was selected as the training medium using the TenCore authoring language. Computer-based training was chosen because of the large number of trainees, the advantages of the reduced overall cost, and the increased trainee retention of course material compared to traditional instruction. The resulting training program utilizes extensive role playing exercises in which employees and supervisors are exposed to real life situations. Extensive interactions by the trainees are required in that they must answer questions concerning the behav ior of individuals, random and for-cause drug testing, and the employee assistance program. Feedback is given in each case. Emphasis is placed on recognition of deteriorating job performance

  15. Reliability high cycle fatigue design of gas turbine blading system using probabilistic goodman diagram

    Energy Technology Data Exchange (ETDEWEB)

    Herman Shen, M.-H. [Ohio State Univ., Columbus, OH (United States). Dept. of Aerospace Engineering and Aviation; Nicholas, T. [MLLN, Wright-Patterson AFB, OH (United States). Air Force Research Lab.

    2001-07-01

    A framework for the probabilistic analysis of high cycle fatigue is developed. The framework will be useful to U.S. Air Force and aeroengine manufacturers in the design of high cycle fatigue in disk or compressor components fabricated from Ti-6Al-4V under a range of loading conditions that might be encountered during service. The main idea of the framework is to characterize vibratory stresses from random input variables due to uncertainties such as crack location, loading, material properties, and manufacturing variability. The characteristics of such vibratory stresses are portrayed graphically as histograms, or probability density function (PDF). The outcome of the probability measures associated with all the values of a random variable exceeding the material capability is achieved by a failure function g(X) defined by the difference between the vibratory stress and Goodman line or surface such that the probability of HCF failure is P{sub f} =P(g(X<0)). Design can then be based on a go-no go criterion based on an assumed risk. The framework can be used to facilitate the development of design tools for the prediction of inspection schedules and reliability in aeroengine components. Such tools could lead ultimately to improved life extension schemes in aging aircraft, and more reliable methods for the design and inspection of critical components. (orig.)

  16. Two scale damage model and related numerical issues for thermo-mechanical high cycle fatigue

    International Nuclear Information System (INIS)

    Desmorat, R.; Kane, A.; Seyedi, M.; Sermage, J.P.

    2007-01-01

    On the idea that fatigue damage is localized at the microscopic scale, a scale smaller than the mesoscopic one of the Representative Volume Element (RVE), a three-dimensional two scale damage model has been proposed for High Cycle Fatigue applications. It is extended here to aniso-thermal cases and then to thermo-mechanical fatigue. The modeling consists in the micro-mechanics analysis of a weak micro-inclusion subjected to plasticity and damage embedded in an elastic meso-element (the RVE of continuum mechanics). The consideration of plasticity coupled with damage equations at micro-scale, altogether with Eshelby-Kroner localization law, allows to compute the value of microscopic damage up to failure for any kind of loading, 1D or 3D, cyclic or random, isothermal or aniso-thermal, mechanical, thermal or thermo-mechanical. A robust numerical scheme is proposed in order to make the computations fast. A post-processor for damage and fatigue (DAMAGE-2005) has been developed. It applies to complex thermo-mechanical loadings. Examples of the representation by the two scale damage model of physical phenomena related to High Cycle Fatigue are given such as the mean stress effect, the non-linear accumulation of damage. Examples of thermal and thermo-mechanical fatigue as well as complex applications on real size testing structure subjected to thermo-mechanical fatigue are detailed. (authors)

  17. High-power UV-LED degradation: Continuous and cycled working condition influence

    Science.gov (United States)

    Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

    2015-09-01

    High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

  18. Probabilistic multi-scale models and measurements of self-heating under multiaxial high cycle fatigue

    International Nuclear Information System (INIS)

    Poncelet, M.; Hild, F.; Doudard, C.; Calloch, S.; Weber, B.

    2010-01-01

    Different approaches have been proposed to link high cycle fatigue properties to thermal measurements under cyclic loadings, usually referred to as 'self-heating tests'. This paper focuses on two models whose parameters are tuned by resorting to self-heating tests and then used to predict high cycle fatigue properties. The first model is based upon a yield surface approach to account for stress multi-axiality at a microscopic scale, whereas the second one relies on a probabilistic modelling of micro-plasticity at the scale of slip-planes. Both model identifications are cost effective, relying mainly on quickly obtained temperature data in self-heating tests. They both describe the influence of the stress heterogeneity, the volume effect and the hydrostatic stress on fatigue limits. The thermal effects and mean fatigue limit predictions are in good agreement with experimental results for in and out-of phase tension-torsion loadings. In the case of fatigue under non-proportional loading paths, the mean fatigue limit prediction error of the critical shear stress approach is three times less than with the yield surface approach. (authors)

  19. Probabilistic multi-scale models and measurements of self-heating under multiaxial high cycle fatigue

    Energy Technology Data Exchange (ETDEWEB)

    Poncelet, M.; Hild, F. [Univ Paris 11, PRES, Univ Paris 06, LMT Cachan, ENS Cachan, CNRS, F-94235 Cachan (France); Doudard, C.; Calloch, S. [Univ Brest, ENIB, ENSIETA, LBMS EA 4325, F-29806 Brest, (France); Weber, B. [ArcelorMittal Maizieres Res Voie Romaine, F-57283 Maizieres Les Metz (France)

    2010-07-01

    Different approaches have been proposed to link high cycle fatigue properties to thermal measurements under cyclic loadings, usually referred to as 'self-heating tests'. This paper focuses on two models whose parameters are tuned by resorting to self-heating tests and then used to predict high cycle fatigue properties. The first model is based upon a yield surface approach to account for stress multi-axiality at a microscopic scale, whereas the second one relies on a probabilistic modelling of micro-plasticity at the scale of slip-planes. Both model identifications are cost effective, relying mainly on quickly obtained temperature data in self-heating tests. They both describe the influence of the stress heterogeneity, the volume effect and the hydrostatic stress on fatigue limits. The thermal effects and mean fatigue limit predictions are in good agreement with experimental results for in and out-of phase tension-torsion loadings. In the case of fatigue under non-proportional loading paths, the mean fatigue limit prediction error of the critical shear stress approach is three times less than with the yield surface approach. (authors)

  20. Metallic CoS₂ nanowire electrodes for high cycling performance supercapacitors.

    Science.gov (United States)

    Ren, Ren; Faber, Matthew S; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

    2015-12-11

    We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g(-1) at a scan rate of 0.01 V s(-1)) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g(-1)) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

  1. Metallic CoS2 nanowire electrodes for high cycling performance supercapacitors

    Science.gov (United States)

    Ren, Ren; Faber, Matthew S.; Dziedzic, Rafal; Wen, Zhenhai; Jin, Song; Mao, Shun; Chen, Junhong

    2015-12-01

    We report metallic cobalt pyrite (CoS2) nanowires (NWs) prepared directly on current collecting electrodes, e.g., carbon cloth or graphite disc, for high-performance supercapacitors. These CoS2 NWs have a variety of advantages for supercapacitor applications. Because the metallic CoS2 NWs are synthesized directly on the current collector, the good electrical connection enables efficient charge transfer between the active CoS2 materials and the current collector. In addition, the open spaces between the sea urchin structure NWs lead to a large accessible surface area and afford rapid mass transport. Moreover, the robust CoS2 NW structure results in high stability of the active materials during long-term operation. Electrochemical characterization reveals that the CoS2 NWs enable large specific capacitance (828.2 F g-1 at a scan rate of 0.01 V s-1) and excellent long term cycling stability (0-2.5% capacity loss after 4250 cycles at 5 A g-1) for pseudocapacitors. This example of metallic CoS2 NWs for supercapacitor applications expands the opportunities for transition metal sulfide-based nanostructures in emerging energy storage applications.

  2. Development of a Very High Cycle Fatigue (VHCF multiaxial testing device

    Directory of Open Access Journals (Sweden)

    M. Vieira

    2016-07-01

    Full Text Available The very high cycle region of the S-N fatigue curve has been the subject of intensive research on the last years, with special focus on axial, bending, torsional and fretting fatigue tests. Very high cycle fatigue can be achieved using ultrasonic exciters which allow for frequency testing of up to 30 kHz. Still, the multiaxial fatigue analysis is not yet developed for this type of fatigue analyses, mainly due to conceptual limitations of these testing devices. In this paper, a device designed to produce biaxial fatigue testing using a single piezoelectric axial exciter is presented, as well as the preliminary testing of this device. The device is comprised of a horn and a specimen, which are both attached to the piezoelectric exciter. The steps taken towards the final geometry of the device are presented. Preliminary experimental testing of the developed device is made using thermographic imaging, strain measurements and vibration speeds and indicates good behaviour of the tested specimen.

  3. Plant accident dynamics of high-temperature reactors with direct gas turbine cycle

    International Nuclear Information System (INIS)

    Waloch, M.L.

    1977-01-01

    In the paper submitted, a one-dimensional accident simulation model for high-temperature reactors with direct-cycle gas turbine (single-cycle facilities) is described. The paper assesses the sudden failure of a gas duct caused by the double-ended break of one out of several parallel pipes before and behind the reactor for a non-integrated plant, leading to major loads in the reactor region, as well as the complete loss of vanes of the compressor for an integrated plant. The results of the calculations show especially high loads for the break of a hot-gas pipe immediately behind the flow restrictors of the reactor outlet, because of prolonged effects of pressure gradients in the reactor region and the maximum core differential pressure. A plant accident dynamics calculation therefore allows to find a compromise between the requirements of stable compressor operation, on the one hand, and small loads in the reactor in the course of an accident, on the other, by establishing in a co-ordinated manner the narrowing ratio of the flow restrictors. (GL) [de

  4. Morphology controlled synthesis of monodisperse cobalt hydroxide for supercapacitor with high performance and long cycle life

    Science.gov (United States)

    Tang, Yongfu; Liu, Yanyan; Yu, Shengxue; Mu, Shichun; Xiao, Shaohua; Zhao, Yufeng; Gao, Faming

    2014-06-01

    A facile hydrothermal process with hexadecyltrimethyl ammonium bromide (CTAB) as the soft template is proposed to tune the morphology and size of cobalt hydroxide (Co(OH)2). Monodisperse β-phase Co(OH)2 nanowires with uniform size are obtained by controlling the CTAB content and the reaction time. Due to the uniform well-defined morphology and stable structure, the Co(OH)2 nanowires material exhibits high capacitive performance and long cycle life. The specific capacitance of the Co(OH)2 nanowires electrode is 358 F g-1 at 0.5 A g-1, and even 325 F g-1 at 10 A g-1. The specific capacitance retention is 86.3% after 5000 charge-discharge cycles at 2 A g-1. Moreover, the asymmetric supercapacitor is assembled with Co(OH)2 nanowires and nitrite acid treated activated carbon (NTAC), which shows an energy density of 13.6 Wh kg-1 at the power density of 153 W kg-1 under a high voltage of 1.6 V, and 13.1 Wh kg-1 even at the power density of 1.88 kW kg-1.

  5. High stability of palladium/kieselguhr composites during absorption/desorption cycling for hydrogen isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Yang, E-mail: lei.y@outlook.com; Liu, Xiaopeng; Li, Shuo; Jiang, Lijun; Zhang, Chao; Li, Shuai; He, Di; Wang, Shumao

    2016-12-15

    Highlights: • Pd/K composites with as high as 57 wt.% of Pd have been successfully prepared. • Palladium particles can be effectively packed into the pores of kieselguhr substrates. • Variation of heat-treatment temperatures hardly affect hydrogen absorption capacity and hydrogen saturation time of the Pd/K. • Anti-pulverization property of Pd/K can be improved by packing palladium into the kieselguhr internal pores and heating at 1300 °C. - Abstract: Palladium/kieselguhr (Pd/K) composites with 57 wt.% of Pd were prepared by an improved dipping and thermal decomposition method and heated at elevated temperature to reduce breakdown during hydrogenation-dehydrogenation cycles. The hydrogen absorption kinetic properties of the samples heated at different temperatures were tested under the condition of 20 °C with 100 kPa hydrogen pressure. The 1300 °C heated Pd/K composites were repeated up to 4010 absorption and desorption cycles at temperature ranges between −40 °C and 200 °C. The results show that the phase structure, hydrogen absorption capacity and hydrogen saturation time of the Pd/K were not affected by the change of heat-treated temperatures. And after heat treatment at 1300 °C, the Pd/K particles were strengthened and fraction of larger than 80 mesh were as high as 93.4%.

  6. Fuel-Cycle and Nuclear Material Disposition Issues Associated with High-Temperature Gas Reactors

    International Nuclear Information System (INIS)

    Shropshire, D.E.; Herring, J.S.

    2004-01-01

    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

  7. High-Level Functional and Operational Requirements for the Advanced Fuel Cycle Facility

    International Nuclear Information System (INIS)

    Charles Park

    2006-01-01

    This document describes the principal functional and operational requirements for the proposed Advanced Fuel Cycle Facility (AFCF). The AFCF is intended to be the world's foremost facility for nuclear fuel cycle research, technology development, and demonstration. The facility will also support the near-term mission to develop and demonstrate technology in support of fuel cycle needs identified by industry, and the long-term mission to retain and retain U.S. leadership in fuel cycle operations. The AFCF is essential to demonstrate a more proliferation-resistant fuel cycle and make long-term improvements in fuel cycle effectiveness, performance and economy

  8. A complete life cycle assessment of high density polyethylene plastic bottle

    Science.gov (United States)

    Treenate, P.; Limphitakphong, N.; Chavalparit, O.

    2017-07-01

    This study was aimed to determine environmental performances of a lubricant oil bottle made from high density polyethylene and to develop potential measures for reducing its impacts. A complete life cycle assessment was carried out to understand a whole effect on the environment from acquiring, processing, using, and disposing the product. Two scenarios of disposal phase; recycle and incineration: were examined to quantify a lesser degree on environmental impact. The results illustrated that major impacts of the two scenarios were at the same categories with the highest contributor of raw material acquisition and pre-processing. However, all impacts in case of recycling provided a lower point than that in case of incineration, except mineral extraction. Finally, feasible measures for reducing the environmental impact of high density polyethylene plastic bottle were proposed in accordance with 3Rs concept.

  9. High-efficiency intracavity second-harmonic enhancement for a few-cycle laser pulse train

    International Nuclear Information System (INIS)

    Cai, Yi; Xu, Shixiang; Zeng, Xuanke; Zou, Da; Li, Jingzhen

    2012-01-01

    This paper presents an intracavity second-harmonic (SH) enhancement technology without the need of input impedance-matching for optimal coupling between the cavity and its input frequency comb. More than 10% SH energy conversion efficiency is available, thus the power of the SH frequency comb can be enhanced beyond 100 relative to single-pass SH generation. Compared with a conventional passive enhancing cavity, for the purpose of high power enhancement, our scheme can operate at much lower finesse and thus broader bandwidth so that it can support several-optical-cycle pulses more easily. If they have the same finesse, both methods perform with similar operating stability. The results show that our novel design is suitable for some applications which need a short wavelength, high intensity, and ultra-broad bandwidth pulse train. (paper)

  10. High-precision atom localization via controllable spontaneous emission in a cycle-configuration atomic system.

    Science.gov (United States)

    Ding, Chunling; Li, Jiahua; Yu, Rong; Hao, Xiangying; Wu, Ying

    2012-03-26

    A scheme for realizing two-dimensional (2D) atom localization is proposed based on controllable spontaneous emission in a coherently driven cycle-configuration atomic system. As the spatial-position-dependent atom-field interaction, the frequency of the spontaneously emitted photon carries the information about the position of the atom. Therefore, by detecting the emitted photon one could obtain the position information available, and then we demonstrate high-precision and high-resolution 2D atom localization induced by the quantum interference between the multiple spontaneous decay channels. Moreover, we can achieve 100% probability of finding the atom at an expected position by choosing appropriate system parameters under certain conditions.

  11. Thermal Stability of Hexamethyldisiloxane (MM for High-Temperature Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2016-03-01

    Full Text Available The design of efficient Organic Rankine Cycle (ORC units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM is investigated in an electrically heated tube. Qualitative results concerning remarks on degradation products as well as quantitative results like the annual degradation rate are presented. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3.5%. Furthermore, the break of a silicon–carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, it is discussed how the results may impact the future design of ORC units.

  12. Low cycle fatigue numerical estimation of a high pressure turbine disc for the AL-31F jet engine

    Directory of Open Access Journals (Sweden)

    Spodniak Miroslav

    2017-01-01

    Full Text Available This article deals with the description of an approximate numerical estimation approach of a low cycle fatigue of a high pressure turbine disc for the AL-31F turbofan jet engine. The numerical estimation is based on the finite element method carried out in the SolidWorks software. The low cycle fatigue assessment of a high pressure turbine disc was carried out on the basis of dimensional, shape and material disc characteristics, which are available for the particular high pressure engine turbine. The method described here enables relatively fast setting of economically feasible low cycle fatigue of the assessed high pressure turbine disc using a commercially available software. The numerical estimation of accuracy of a low cycle fatigue depends on the accuracy of required input data for the particular investigated object.

  13. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat.

    Science.gov (United States)

    Hackley, Jason D; Kislitsyn, Dmitry A; Beaman, Daniel K; Ulrich, Stefan; Nazin, George V

    2014-10-01

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  14. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat

    Energy Technology Data Exchange (ETDEWEB)

    Hackley, Jason D.; Kislitsyn, Dmitry A.; Beaman, Daniel K.; Nazin, George V., E-mail: gnazin@uoregon.edu [Department of Chemistry and Biochemistry, 1253 University of Oregon, Eugene, Oregon 97403 (United States); Ulrich, Stefan [RHK Technology, Inc., 1050 East Maple Road, Troy, Michigan 48083 (United States)

    2014-10-15

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  15. Order effect of strain applications in low-cycle cumulative fatigue at high temperatures

    International Nuclear Information System (INIS)

    Bui-Quoc, T.; Biron, A.

    1977-01-01

    Recent test results on cumulative damage with two strain levels on a stainless steel (AISI 304) at room temperature, 537 and 650 0 C show that the sum of cycle-ratios can be significantly smaller than unity for decreasing levels; the opposite has been noted for increasing levels. As a consequence, the use of the linear damage rule (Miner's law) for life predictions is not conservative in many cases. Since the double linear damage rule (DLDR), originally developed by Manson et al. for room temperature applications, takes the order effect of cyclic loading into consideration, an extension of this rule for high temperature cases may be a potentially useful tool. The present paper is concerned with such an extension. For cumulative damage tests with several levels, according to the DLDR, the summation is applied separately for crack initiation and crack propagation stages, and failure is then assumed to occur when the sum is equal to unity for both stages. Application of the DLDR consists in determining the crack propagation stage Nsub(p) associated with a particular number of cycles at failure N, i.e. Nsub(p)=PNsup(a) where exponent a and coefficient P had been assumed to be equal to 0.6 and 14 respectively for several materials at room temperature. When the DLDR is applied (with a=0.6 and P=14) to predict the remaining life at the second strain level (for two-level cumulative damage) for 304 stainless steel at room temperature 537 0 C and 650 0 C, the results show that the damage due to the first strain level is over-emphasized for decreasing levels when the damaging cycle-ratio is small. For increasing levels, the damage is underestimated and in some testing conditions this damage is simply ignored

  16. High resolution remote sensing for reducing uncertainties in urban forest carbon offset life cycle assessments.

    Science.gov (United States)

    Tigges, Jan; Lakes, Tobia

    2017-10-04

    Urban forests reduce greenhouse gas emissions by storing and sequestering considerable amounts of carbon. However, few studies have considered the local scale of urban forests to effectively evaluate their potential long-term carbon offset. The lack of precise, consistent and up-to-date forest details is challenging for long-term prognoses. Therefore, this review aims to identify uncertainties in urban forest carbon offset assessment and discuss the extent to which such uncertainties can be reduced by recent progress in high resolution remote sensing. We do this by performing an extensive literature review and a case study combining remote sensing and life cycle assessment of urban forest carbon offset in Berlin, Germany. Recent progress in high resolution remote sensing and methods is adequate for delivering more precise details on the urban tree canopy, individual tree metrics, species, and age structures compared to conventional land use/cover class approaches. These area-wide consistent details can update life cycle inventories for more precise future prognoses. Additional improvements in classification accuracy can be achieved by a higher number of features derived from remote sensing data of increasing resolution, but first studies on this subject indicated that a smart selection of features already provides sufficient data that avoids redundancies and enables more efficient data processing. Our case study from Berlin could use remotely sensed individual tree species as consistent inventory of a life cycle assessment. However, a lack of growth, mortality and planting data forced us to make assumptions, therefore creating uncertainty in the long-term prognoses. Regarding temporal changes and reliable long-term estimates, more attention is required to detect changes of gradual growth, pruning and abrupt changes in tree planting and mortality. As such, precise long-term urban ecological monitoring using high resolution remote sensing should be intensified

  17. Improvement of high voltage cycling performance and thermal stability of lithium-ion cells by use of a thiophene additive

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Soo; Sun, Yang-Kook; Kim, Dong-Won [Department of Chemical Engineering, Hanyang University, Seungdong-gu, Seoul 133-791 (Korea); Noh, Jaegeun [Department of Chemistry, Hanyang University, Seungdong-gu, Seoul 133-791 (Korea); Song, Kwang Soup [Advanced Medical Device Center, Korea Electrotechnology, Research Institute, Ansan, Gyeonggi-do 426-170 (Korea)

    2009-10-15

    This study demonstrates that the addition of thiophene improves the cycle life of lithium-ion cells at high voltage. Electrochemical impedance spectroscopy results suggest that addition of thiophene significantly suppresses the increase of the charge transfer resistance that occurs during cycling up to high voltage. Differential scanning calorimetric studies showed that the thermal stability of fully charged LiCoO{sub 2} cathode was also enhanced in the presence of thiophene. (author)

  18. Effects of Beetroot Juice Supplementation on a 30-s High-Intensity Inertial Cycle Ergometer Test

    Directory of Open Access Journals (Sweden)

    Raul Domínguez

    2017-12-01

    Full Text Available Background: Beetroot juice (BJ is rich in inorganic nitrates and has proved effective at increasing blood nitric oxide (NO levels. When used as a supplement BJ has shown an ergogenic effect on cardiorespiratory resistance exercise modalities, yet few studies have examined its impact on high intensity efforts. Objective: To assess the effects of BJ intake on anaerobic performance in a Wingate test. Methods: Fifteen trained men (age 21.46 ± 1.72 years, height 1.78 ± 0.07 cm and weight 76.90 ± 8.67 kg undertook a 30-s maximum intensity test on an inertial cycle ergometer after drinking 70 mL of BJ (5.6 mmol NO3− or placebo. Results: Despite no impacts of BJ on the mean power recorded during the test, improvements were produced in peak power (6% (p = 0.034, average power 0–15 s (6.7% (p = 0.048 and final blood lactate levels (82.6% (p < 0.001, and there was a trend towards a shorter time taken to attain peak power (−8.4% (p = 0.055. Conclusions: Supplementation with BJ has an ergonomic effect on maximum power output and on average power during the first 15 s of a 30-s maximum intensity inertial cycle ergometer test.

  19. Life Cycle Analysis of High Quality Recycled Aggregate Produced byHeating and Rubbing Method

    Science.gov (United States)

    Shima, Hirokazu; Matsuhashi, Ryuji; Yoshida, Yoshikuni; Tateyashiki, Hisashi

    Most of demolished concrete is recycled as road subbase, but its generation is expected to increase rapidly and exceed the demand of road subbase in a near future. To promote the recycling of concrete, the technology to produce high quality recycled aggregate by the heating and rubbing method has been developed. In this method, demolished concrete is heated up to about 300°C in a heater to make cement paste brittle with its dehydration. The heated concrete is then rubbed in two mills to recover the recycled aggregate, while the paste is removed from the surface of aggregate and collected as cement fine powder. In this method, much energy is consumed to heat and rub concrete; however, the cement fine powder is utilized for a soil stabilizer and cement raw materials, so that the environmental load is reduced in cement manufacturing. The life cycle analysis of the recycled aggregate is carried out to evaluate this technology. As a result, the life cycle CO2 is a negative value because the deduction of CO2 emission in cement manufacturing by the powder is much large. This technology is proved to be very effective to reduce CO2.

  20. Fatigue response of a PZT multilayer actuator under high-field electric cycling with mechanical preload

    Science.gov (United States)

    Wang, Hong; Wereszczak, Andrew A.; Lin, Hua-Tay

    2009-01-01

    An electric fatigue test system was developed for evaluating the reliability of piezoelectric actuators with a mechanical loading capability. Fatigue responses of a lead zirconate titanate (PZT) multilayer actuator with a platethrough electrode configuration were studied under an electric field (1.7 times that of the coercive field of PZT material) and a concurrent mechanical preload (30.0 MPa). A total of 109 cycles was carried out. Variations in charge density and mechanical strain under the high electric field and constant mechanical loads were observed during the fatigue test. The dc and the first harmonic (at 10 Hz) dielectric and piezoelectric coefficients were subsequently characterized using fast Fourier transformation. Both the dielectric and the piezoelectric coefficients exhibited a monotonic decrease prior to 2.86×108 cycles under certain preloading conditions, and then fluctuated. Both the dielectric loss tangent and the piezoelectric loss tangent also fluctuated after a decrease. The results are interpreted and discussed with respect to domain wall activities, microdefects, and other anomalies.

  1. Effect of rare earth elements on high cycle fatigue behavior of AZ91 alloy

    International Nuclear Information System (INIS)

    Mokhtarishirazabad, M.; Boutorabi, S.M.A.; Azadi, M.; Nikravan, M.

    2013-01-01

    This article investigates effects of adding rare earth elements (RE) into a magnesium–aluminum–zinc alloy (the AZ91 alloy) on its high cycle fatigue (HCF) behavior. For this purpose, AZ91 and AZ91+1% RE (AZE911) alloys were gravity casted in a metallic die. RE elements were added to the AZ91 alloy in the form of mischmetals. Microscopic evaluations with the scanning electron microscopy (SEM) and mechanical tests include tensile, hardness and HCF behaviors, were performed on prepared samples. Rotary bending fatigue tests were carried out at a stress ratio (R) of −1 and a frequency of 125 Hz, at the room temperature, in the air. The microscopic investigation demonstrates that the addition of 1% RE elements leads to the formation of Al 11 RE 3 intermetallic particles which is associated to the reduction of β-(Mg 17 Al 12 ) phases. Results of mechanical experiments suggest a negligible effect of adding 1% RE elements on mechanical properties of the AZ91 alloy. Curves of stress-life (S–N) shows an increase in the fatigue strength at 10 5 cycles, from 100±10 MPa to 135±10 MPa, when RE elements were added to the AZ91 alloy

  2. Effect of rare earth elements on high cycle fatigue behavior of AZ91 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtarishirazabad, M., E-mail: mehdi-mokhtari@hotmail.com [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Boutorabi, S.M.A. [School of Metallurgy and Materials Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Azadi, M.; Nikravan, M. [Irankhodro Powertrain Company (IPCO), Tehran (Iran, Islamic Republic of)

    2013-12-10

    This article investigates effects of adding rare earth elements (RE) into a magnesium–aluminum–zinc alloy (the AZ91 alloy) on its high cycle fatigue (HCF) behavior. For this purpose, AZ91 and AZ91+1% RE (AZE911) alloys were gravity casted in a metallic die. RE elements were added to the AZ91 alloy in the form of mischmetals. Microscopic evaluations with the scanning electron microscopy (SEM) and mechanical tests include tensile, hardness and HCF behaviors, were performed on prepared samples. Rotary bending fatigue tests were carried out at a stress ratio (R) of −1 and a frequency of 125 Hz, at the room temperature, in the air. The microscopic investigation demonstrates that the addition of 1% RE elements leads to the formation of Al{sub 11}RE{sub 3} intermetallic particles which is associated to the reduction of β-(Mg{sub 17}Al{sub 12}) phases. Results of mechanical experiments suggest a negligible effect of adding 1% RE elements on mechanical properties of the AZ91 alloy. Curves of stress-life (S–N) shows an increase in the fatigue strength at 10{sup 5} cycles, from 100±10 MPa to 135±10 MPa, when RE elements were added to the AZ91 alloy.

  3. High cycle fatigue test and regression methods of S-N curve

    International Nuclear Information System (INIS)

    Kim, D. W.; Park, J. Y.; Kim, W. G.; Yoon, J. H.

    2011-11-01

    The fatigue design curve in the ASME Boiler and Pressure Vessel Code Section III are based on the assumption that fatigue life is infinite after 106 cycles. This is because standard fatigue testing equipment prior to the past decades was limited in speed to less than 200 cycles per second. Traditional servo-hydraulic machines work at frequency of 50 Hz. Servo-hydraulic machines working at 1000 Hz have been developed after 1997. This machines allow high frequency and displacement of up to ±0.1 mm and dynamic load of ±20 kN are guaranteed. The frequency of resonant fatigue test machine is 50-250 Hz. Various forced vibration-based system works at 500 Hz or 1.8 kHz. Rotating bending machines allow testing frequency at 0.1-200 Hz. The main advantage of ultrasonic fatigue testing at 20 kHz is performing Although S-N curve is determined by experiment, the fatigue strength corresponding to a given fatigue life should be determined by statistical method considering the scatter of fatigue properties. In this report, the statistical methods for evaluation of fatigue test data is investigated

  4. Thermodynamic optimisation and analysis of four Kalina cycle layouts for high temperature applications

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2015-01-01

    The Kalina cycle has seen increased interest in the last few years as an efficient alternative to the conventional steam Rankine cycle. However, the available literature gives little information on the algorithms to solve or optimise this inherently complex cycle. This paper presents a detailed a...

  5. Unregulated greenhouse gas and ammonia emissions from current technology heavy-duty vehicles.

    Science.gov (United States)

    Thiruvengadam, Arvind; Besch, Marc; Carder, Daniel; Oshinuga, Adewale; Pasek, Randall; Hogo, Henry; Gautam, Mridul

    2016-11-01

    The study presents the measurement of carbonyl, BTEX (benzene, toluene, ethyl benzene, and xylene), ammonia, elemental/organic carbon (EC/OC), and greenhouse gas emissions from modern heavy-duty diesel and natural gas vehicles. Vehicles from different vocations that included goods movement, refuse trucks, and transit buses were tested on driving cycles representative of their duty cycle. The natural gas vehicle technologies included the stoichiometric engine platform equipped with a three-way catalyst and a diesel-like dual-fuel high-pressure direct-injection technology equipped with a diesel particulate filter (DPF) and a selective catalytic reduction (SCR). The diesel vehicles were equipped with a DPF and SCR. Results of the study show that the BTEX emissions were below detection limits for both diesel and natural gas vehicles, while carbonyl emissions were observed during cold start and low-temperature operations of the natural gas vehicles. Ammonia emissions of about 1 g/mile were observed from the stoichiometric natural gas vehicles equipped with TWC over all the driving cycles. The tailpipe GWP of the stoichiometric natural gas goods movement application was 7% lower than DPF and SCR equipped diesel. In the case of a refuse truck application the stoichiometric natural gas engine exhibited 22% lower GWP than a diesel vehicle. Tailpipe methane emissions contribute to less than 6% of the total GHG emissions. Modern heavy-duty diesel and natural gas engines are equipped with multiple after-treatment systems and complex control strategies aimed at meeting both the performance standards for the end user and meeting stringent U.S. Environmental Protection Agency (EPA) emissions regulation. Compared to older technology diesel and natural gas engines, modern engines and after-treatment technology have reduced unregulated emissions to levels close to detection limits. However, brief periods of inefficiencies related to low exhaust thermal energy have been shown to

  6. Mean stress effects on high-cycle fatigue of Alloy 718

    International Nuclear Information System (INIS)

    Korth, G.E.

    1980-07-01

    This report covers an investigation of the effects of tensile mean stress on the high-cycle fatigue properties of Alloy 718. Three test temperatures (24, 427, and 649 degree C) were employed, and there were tests in both strain and load control. Results were compared with three different models: linear Modified-Goodman, Peterson cubic, and stress-strain parameter. The linear Modified-Goodman model gave good correlation with actual test data for low and moderate mean stress values, but the stress-strain parameter showed excellent correlation over the entire range of possible mean stresses and therefore is recommended for predicting mean stress effects of Alloy 718. 13 refs., 12 figs

  7. High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle

    Science.gov (United States)

    Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas de Paula, Mateus; Pütz, Sandro; Sexton, Joseph O.; Song, Danxia; Huth, Andreas

    2017-03-01

    Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1-14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle.

  8. Instantaneous strain measurements during high-temperature stress cycling of a dispersion-strengthened niobium alloy

    International Nuclear Information System (INIS)

    Farkas, D.M.; Mishra, R.S.; Mukherjee, A.K.

    1995-01-01

    Experimental results obtained from stress cycling tests performed during high-temperature creep of a dispersion strengthened niobium alloy indicate that the instantaneous strain following the stress change decreases with accumulated strain. The true work-hardening rate was shown to be a small fraction of the elastic modulus which remained fairly constant throughout the strain history. The instantaneous strain change from a stress addition was typically greater than the strain from the corresponding stress reduction. This effect is quite pronounced for small stress changes and diminishes as the magnitude of the stress change increases. This implies that the mobility of dislocations is impeded in the reverse direction unless the magnitude of stress reduction exceeds the value of the internal stress

  9. Shot-Peening Effect on High Cycling Fatigue of Al-Cu Alloy

    Science.gov (United States)

    Fouad, Yasser; Metwally, Mostafa El

    2013-12-01

    The present work was aimed at evaluating the effects of shot-peening on the high cycle fatigue performance of the age-hardening aircraft alloy Al 2024 at different almen intensities. Shot-peening to full coverage (100 pct) was performed using spherically conditioned cut wire (SCCW 14) with an average shot size of 0.36 mm and at almen intensities of 0.1, 0.2, and 0.3 mmA. After applying the various mechanical surface treatments, the changes in the surface and near-surface layer properties such as microhardness, residual stress-depth profiles, and surface roughness were determined. The microhardness, surface roughness, and the residual stresses increased proportionally with the almen intensity. Electropolitically polished conditions were used as reference in the mechanically surface treated specimens. A significant improvement was seen in the fatigue performance of the 0.1 mmA.

  10. A Modified Fatigue Damage Model for High-Cycle Fatigue Life Prediction

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2016-01-01

    Full Text Available Based on the assumption of quasibrittle failure under high-cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Then, finite element method (FEM is used to describe the failure process of metal material. The increment of specimen’s life and damage state can be researched using damage mechanics-FEM. Finally, the lifetime of the specimen is got at the given stress level. The damage mechanics-FEM is inserted into ABAQUS with subroutine USDFLD and the Python language is used to simulate the fatigue process of titanium alloy specimens. The simulation results have a good agreement with the testing results under constant amplitude loading, which proves the accuracy of the method.

  11. High-cycle fatigue characteristics of weldable steel for light-water reactors

    International Nuclear Information System (INIS)

    Klesnil, M.; Polak, J.; Obrtlik, K.; Troshchenko, V.T.; Mishchenko, Yu.I.; Khamaza, L.A.

    1982-01-01

    Czechoslovak and Soviet 15Kh2NMFA steel was used for running fatigue tests at temperatures of 20, 350 and 400 degC in the high-cycle range with various loading regimes. The results show that at the given temperatures in this type of steel a cyclic softening occurs. The fatigue characteristics were measured with great dispersion of results, but within this dispersion they are almost identical for various steels at the same temperature. Increased temperature results in the decrease in the amplitude of cyclic deformation stress and in the increase in the amplitude of plastic deformation. The diversity in the values of cyclic plasticity and stress response measured in the given mode may be explained by the lower level of softening and the non-homogeneous cyclic plastic deformation of material under the given constant conditions. (J.B.)

  12. Effect of β-alanine plus sodium bicarbonate on high-intensity cycling capacity.

    Science.gov (United States)

    Sale, Craig; Saunders, Bryan; Hudson, Sean; Wise, John A; Harris, Roger C; Sunderland, Caroline D

    2011-10-01

    We examined the effect of β-alanine supplementation plus sodium bicarbonate on high-intensity cycling capacity. Twenty males (age = 25 ± 5 yr, height = 1.79 ± 0.06 m, body mass = 80.0 ± 10.3 kg) were assigned to either a placebo (P) or a β-alanine (BA; 6.4 g·d(-1) for 4 wk) group based on power max, completing four cycling capacity tests at 110% of power max (CCT110%) to determine time to exhaustion (TTE) and total work done. A CCT(110%) was performed twice (habituation and baseline) before supplementation (with maltodextrin [MD]) and twice after supplementation (with MD and with sodium bicarbonate [SB]), using a crossover design with 2 d of rest between trials, creating four study conditions (PMD, PSB, BAMD, and BASB). Blood pH, Lactate, bicarbonate and base excess were determined at baseline, before exercise, immediately after exercise, and 5 min after exercise. Data were analyzed using repeated-measures ANOVA. TTE was increased in all conditions after supplementation (+1.6% PMD, +6.5% PSB, +12.1% BAMD, and +16.2% BASB). Both BAMD and BASB resulted in significantly improved TTE compared with that before supplementation (P ≤ 0.01). Although further increases in TTE (4.1%) were shown in BASB compared with BAMD, these differences were not significant (P = 0.74). Differences in total work done were similar to those of TTE. Blood bicarbonate concentrations were significantly (P ≤ 0.001) elevated before exercise in PSB and BASB but not in PMD or BAMD. Blood lactate concentrations were significantly elevated after exercise, remaining elevated after 5 min of recovery (P ≤ 0.001) and were highest in PSB and BASB. Results show that BA improved high-intensity cycling capacity. However, despite a 6-s (∼4%) increase in TTE with the addition of SB, this did not reach statistical significance, but magnitude-based inferences suggested a ∼70% probability of a meaningful positive difference.

  13. An optimized approach towards the treatment of high level liquid waste in the nuclear cycle

    International Nuclear Information System (INIS)

    Maio, V.; Todd, T.; Law, J.; Roach, J.; Sabharwall, P.

    2006-01-01

    Full text: One key long-standing issue that must be overcome to realize the successful growth of nuclear power is an economical, politically acceptable, stakeholder-compatible, and technically feasible resolution pertaining to the safe treatment and disposal of high-level liquid radioactive waste (HLLW). In addition to spent nuclear reactor fuel, HLLW poses a unique challenge in regard to environmental and security concerns, since future scenarios for a next generation of domestic and commercialized nuclear fuel cycle infrastructures must include reprocessing - the primary source of HLLW-to ensure the cost effectiveness of nuclear power as well as mitigate any threats as related to proliferation. Past attempts to immobilize HLLW - generated by both the weapons complex and the commercial power sector-have been plagued by an inability to convince the public and some technical peer reviewers that any proposed geological disposal sites (e.g., Yucca Mountain) can accommodate and contain the HLLW for a period of geological time equivalent to ten fold the radiological half-life of the longest lived of the actinides remaining after reprocessing. The paper explores combined equipment and chemical processing approaches for advancing and economizing the immobilization of high level liquid waste to ensure its long term durability, its decoupling from the unknown behavior of the repository over long geological time periods, and its economical formulation as required for the nuclear fuel cycle of the future. One approach involves the investigation of crystalline based waste forms as opposed to the glass/amorphous based waste forms, and how recent developments in crystalline forms show promise in sequestering the long lived actinides for over tens of millions of years. Another approach -compatible with the first- involves the use of an alternative melter technology-the Cold Crucible Induction Melter (CCIM)- to overcome the engineering material problems of Joule Heated Meters (JHM

  14. Redesigning axial-axial (biaxial) cruciform specimens for very high cycle fatigue ultrasonic testing machines.

    Science.gov (United States)

    Montalvão, Diogo; Wren, Andrew

    2017-11-01

    The necessity to increase performances in terms of lifetime and security in mechanical components or structures is the motivation for intense research in fatigue. Applications range from aeronautics to medical devices. With the development of new materials, there is no longer a fatigue limit in the classical sense, where it was accepted that the fatigue limit is the stress level such that there is no fracture up to 1E7 cycles. The recent development of ultrasonic testing machines where frequencies can go as high as 20 kHz or over enabled tests to be extended to ranges larger than 1E9 in just a few days. This area of studies is now known as Very High Cycle Fatigue (VHCF). On the other hand, most of the existing test equipment in the market for both classical and VHCF are uniaxial test machines. However, critical components used in Engineering applications are usually subjected to complex multi-axial loading conditions. In this paper, it is presented the methodology to redesigning existing cruciform test specimens that can be used to create an in-plane biaxial state of stress when used in 'uniaxial' VHCF ultrasonic testing machines (in this case, the term 'uniaxial' is used not because of the state of stress created at the centre of the specimen, but because of the direction at which the load is applied). The methodology is explained in such a way that it can be expanded to other existing designs, namely cruciform designs, that are not yet used in VHCF. Also, although the approach is presented in simple and logical terms, it may not be that obvious for those who have a more focused approach on fatigue rather than on modal analysis. It is expected that by contributing to bridging the gap between the sciences of modal analysis and fatigue, this research will help and encourage others exploiting new capabilities in VHCF.

  15. Structure and Stability of High-Pressure Dolomite with Implications for the Earth's Deep Carbon Cycle

    Science.gov (United States)

    Solomatova, N. V.; Asimow, P. D.

    2014-12-01

    Carbon is subducted into the mantle primarily in the form of metasomatically calcium-enriched basaltic rock, calcified serpentinites and carbonaceous ooze. The fate of these carbonates in subduction zones is not well understood. End-member CaMg(CO3)2 dolomite typically breaks down into two carbonates at 2-7 GPa, which may further decompose to oxides and CO2-bearing fluid. However, high-pressure X-ray diffraction experiments have recently shown that the presence of iron may be sufficient to stabilize dolomite I to high pressures, allowing the transformation to dolomite II at 17 GPa and subsequently to dolomite III at 35 GPa [1][2]. Such phases may be a principal host for deeply subducted carbon. The structure and equation of state of these high-pressure phases is debated and the effect of varying concentrations of iron is unknown, creating a need for theoretical calculations. Here we compare calculated dolomite structures to experimentally observed phases. Using the Vienna ab-initio simulation package (VASP) interfaced with a genetic algorithm that predicts crystal structures (USPEX), a monoclinic phase with space group 5 ("dolomite sg5") was found for pure end-member dolomite. Dolomite sg5 has a lower energy than reported dolomite structures and an equation of state that resembles that of dolomite III. It is possible that dolomite sg5 is not achieved experimentally due to a large energy barrier and a correspondingly large required volume drop, resulting in the transformation to metastable dolomite II. Due to the complex energy landscape for candidate high-pressure dolomite structures, it is likely that several competing polymorphs exist. Determining the behavior of high-pressure Ca-Mg-Fe(-Mn) dolomite phases in subduction environments is critical for our understanding of the Earth's deep carbon cycle and supercell calculations with Fe substitution are in progress. [1] Mao, Z., Armentrout, M., Rainey, E., Manning, C. E., Dera, P., Prakapenka, V. B., and Kavner, A

  16. Identification of low cycle fatigue parameters of high strength low-alloy (HSLA steel at room temperature

    Directory of Open Access Journals (Sweden)

    S. Bulatović

    2014-10-01

    Full Text Available Low cycle fatigue test was performed in ambient atmosphere at room temperature. Cycle loading of material, in case of High strength low-alloy steel, entails modifications of its properties and in this paper is therefore shown behavior of fatigue life using low cycle fatigue parameters. More precisely, crack initiation life of tested specimens was computed using theory of Coffin-Manson relation during the fatigue loading. The geometry of the stabilized hysteresis loop of welded joint HSLA steel, marked as Nionikral 70, is also analyzed. This stabilized hysteresis loop is very important for determination of materials properties.

  17. Effects of Coatings on the High-Cycle Fatigue Life of Threaded Steel Samples

    Science.gov (United States)

    Eder, M. A.; Haselbach, P. U.; Mishin, O. V.

    2018-05-01

    In this work, high-cycle fatigue is studied for threaded cylindrical high-strength steel samples coated using three different industrial processes: black oxidation, normal-temperature galvanization and high-temperature galvanization. The fatigue performance in air is compared with that of uncoated samples. Microstructural characterization revealed the abundant presence of small cracks in the zinc coating partially penetrating into the steel. This is consistent with the observation of multiple crack initiation sites along the thread in the galvanized samples, which led to crescent type fracture surfaces governed by circumferential growth. In contrast, the black oxidized and uncoated samples exhibited a semicircular segment type fracture surface governed by single-sided growth with a significantly longer fatigue life. Numerical fatigue life prediction based on an extended Paris-law formulation has been conducted on two different fracture cases: 2D axisymmetric multisided crack growth and 3D single-sided crack growth. The results of this upper-bound and lower-bound approach are in good agreement with experimental data and can potentially be used to predict the lifetime of bolted components.

  18. AREVA Modular Steam CycleHigh Temperature Gas-Cooled Reactor Development Progress

    International Nuclear Information System (INIS)

    Lommers, L.; Shahrokhi, F.; Southworth, F.; Mayer, J. III

    2014-01-01

    The AREVA Steam CycleHigh Temperature Gas-Cooled Reactor (SCHTGR) is a modular graphite-moderated gas-cooled reactor currently being developed to support a wide variety of applications including industrial process heat, high efficiency electricity generation, and cogeneration. It produces high temperature superheated steam which makes it a good match for many markets currently dependent on fossil fuels for process heat. Moreover, the intrinsic safety characteristics of the SC-HTGR make it uniquely qualified for collocation with large industrial process heat users which is necessary for serving these markets. The NGNP Industry Alliance has selected the AREVA SC-HTGR as the basis for future development work to support commercial HTGR deployment. This paper provides a concise description of the SC-HTGR concept, followed by a summary of recent development activities. Since this concept was introduced, ongoing design activities have focused primarily on confirming key system capabilities and the suitability for potential future markets. These evaluations continue to confirm the suitability of the SC-HTGR for a variety of potential applications that are currently dependent on fossil fuels. (author)

  19. The ethanol heavy-duty truck fleet demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    This project was designed to test and demonstrate the use of a high- percentage ethanol-blended fuel in a fleet of heavy-duty, over-the- road trucks, paying particular attention to emissions, performance, and repair and maintenance costs. This project also represents the first public demonstration of the use of ethanol fuels as a viable alternative to conventional diesel fuel in heavy-duty engines.

  20. High-energy few-cycle pulse compression through self-channeling in gases

    International Nuclear Information System (INIS)

    Hauri, C.; Merano, M.; Trisorio, A.; Canova, F.; Canova, L.; Lopez-Martens, R.; Ruchon, T.; Engquist, A.; Varju, K.; Gustafsson, E.

    2006-01-01

    Complete test of publication follows. Nonlinear spectral broadening of femtosecond optical pulses by intense propagation in a Kerr medium followed by temporal compression constitutes the Holy Grail for ultrafast science since it allows the generation of intense few-cycle optical transients from longer pulses provided by now commercially available femtosecond lasers. Tremendous progress in high-field and attosecond physics achieved in recent years has triggered the need for efficient pulse compression schemes producing few-cycle pulses beyond the mJ level. We studied a novel pulse compression scheme based on self-channeling in gases, which promises to overcome the energy constraints of hollow-core fiber compression techniques. Fundamentally, self-channeling at high laser powers in gases occurs when the self-focusing effect in the gas is balanced through the dispersion induced by the inhomogeneous refractive index resulting from optically-induced ionization. The high nonlinearity of the ionization process poses great technical challenges when trying to scale this pulse compression scheme to higher energies input energies. Light channels are known to be unstable under small fluctuations of the trapped field that can lead to temporal and spatial beam breakup, usually resulting in the generation of spectrally broad but uncompressible pulses. Here we present experimental results on high-energy pulse compression of self-channeled 40-fs pulses in pressure-gas cells. In the first experiment, performed at the Lund Laser Center in Sweden, we identified a particular self-channeling regime at lower pulse energies (0.8 mJ), in which the ultrashort pulses are generated with negative group delay dispersion (GDD) such that they can be readily compressed down to near 10-fs through simple material dispersion. Pulse compression is efficient (70%) and exhibits exceptional spatial and temporal beam stability. In a second experiment, performed at the LOA-Palaiseau in France, we

  1. Sodium bicarbonate and high-intensity-cycling capacity: variability in responses.

    Science.gov (United States)

    Saunders, Bryan; Sale, Craig; Harris, Roger C; Sunderland, Caroline

    2014-07-01

    To determine whether gastrointestinal (GI) distress affects the ergogenicity of sodium bicarbonate and whether the degree of alkalemia or other metabolic responses is different between individuals who improve exercise capacity and those who do not. Twenty-one men completed 2 cycling-capacity tests at 110% of maximum power output. Participants were supplemented with 0.3 g/kg body mass of either placebo (maltodextrin) or sodium bicarbonate (SB). Blood pH, bicarbonate, base excess, and lactate were determined at baseline, preexercise, immediately postexercise, and 5 min postexercise. SB supplementation did not significantly increase total work done (TWD; P = .16, 46.8 ± 9.1 vs 45.6 ± 8.4 kJ, d = 0.14), although magnitude-based inferences suggested a 63% likelihood of a positive effect. When data were analyzed without 4 participants who experienced GI discomfort, TWD (P = .01) was significantly improved with SB. Immediately postexercise blood lactate was higher in SB for the individuals who improved but not for those who did not. There were also differences in the preexercise-to-postexercise change in blood pH, bicarbonate, and base excess between individuals who improved and those who did not. SB improved high-intensity-cycling capacity but only with the exclusion of participants experiencing GI discomfort. Differences in blood responses suggest that SB may not be beneficial to all individuals. Magnitude-based inferences suggested that the exercise effects are unlikely to be negative; therefore, individuals should determine whether they respond well to SB supplementation before competition.

  2. Expectancy of ergogenicity from sodium bicarbonate ingestion increases high-intensity cycling capacity.

    Science.gov (United States)

    Higgins, Matthew F; Shabir, Akbar

    2016-04-01

    This study examined whether expectancy of ergogenicity of a commonly used nutritional supplement (sodium bicarbonate; NaHCO3) influenced subsequent high-intensity cycling capacity. Eight recreationally active males (age, 21 ± 1 years; body mass, 75 ± 8 kg; height, 178 ± 4 cm; WPEAK = 205 ± 22 W) performed a graded incremental test to assess peak power output (WPEAK), one familiarisation trial and two experimental trials. Experimental trials consisted of cycling at 100% WPEAK to volitional exhaustion (TLIM) 60 min after ingesting either a placebo (PLA: 0.1 g·kg(-1) sodium chloride (NaCl), 4 mL·kg(-1) tap water, and 1 mL·kg(-1) squash) or a sham placebo (SHAM: 0.1 g·kg(-1) NaCl, 4 mL·kg(-1) carbonated water, and 1 mL·kg(-1) squash). SHAM aimed to replicate the previously reported symptoms of gut fullness (GF) and abdominal discomfort (AD) associated with NaHCO3 ingestion. Treatments were administered double blind and accompanied by written scripts designed to remain neutral (PLA) or induce expectancy of ergogenicity (SHAM). After SHAM mean TLIM increased by 9.5% compared to PLA (461 ± 148 s versus 421 ± 150 s; P = 0.048, d = 0.3). Ratings of GF and AD were mild but ~1 unit higher post-ingestion for SHAM. After 3 min TLIM overall ratings of perceived exertion were 1.4 ± 1.3 units lower for SHAM compared to PLA (P = 0.020, d = 0.6). There were no differences between treatments for blood lactate, blood glucose, or heart rate. In summary, ergogenicity after NaHCO3 ingestion may be influenced by expectancy, which mediates perception of effort during subsequent exercise. The observed ergogenicity with SHAM did not affect our measures of cardiorespiratory physiology or metabolic flux.

  3. High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis.

    Directory of Open Access Journals (Sweden)

    Hee Jin Shim

    Full Text Available Ionizing radiation (IR treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.

  4. High temperature gas-cooled reactors - once-through fuel cycle

    International Nuclear Information System (INIS)

    1979-03-01

    The HTGR, because of a unique combination of design characteristics, is a resource-efficient and cost-effective reactor. In the HTGR, the low power density core, coated particle fuel design, and gas cooling combine to provide high neutron economy, fuel burnup and thermodynamic efficiency. The uranium resource requirements for the current MEU/Th cycle with annual refueling results in a 30-year net U 3 O 8 requirement of 4280 ST/GWe. The basic design of the HTGR refueling scheme, whereby only selected regions of the core need be accessible during each refueling, makes fuel utilization improvements through semi-annual refueling an acceptable alternative in terms of plant availability. This alternative reduces the 30-year U 3 O 8 requirement by about 9%. Additional resource utilization improvements of 10% could be realized by improved fuel management techniques. In addition to improvements achieved in reactor technology, uranium utilization can also be improved by reducing the U-235 content in the depleted uranium (tails) produced by the isotope separation facility. If the Advanced Isotope Separation Technology program, currently under development by the United States, results in a lowering of the tails assay from 0.20 w/o to 0.05 w/o the uranium feed requirement for MEU/Th cycles would be further reduced by 22%. A total improvement of 41% over the already relatively low 4280 ST/GWe net lifetime U 3 O 8 requirement would result in a 2525 ST/GWe 30-year yet U 3 O 8 requirement if all of the potential improvements were realized

  5. Behavior of Plain Concrete of a High Water-Cement Ratio after Freeze-Thaw Cycles

    OpenAIRE

    Shang, Huai-Shuai; Yi, Ting-Hua; Song, Yu-Pu

    2012-01-01

    An experimental study of plain concrete specimens of water-cement ratio 0.55, subjected to 0, 15, 25, 40, 50 and 75 cycles of freeze-thaw was completed. The dynamic modulus of elasticity (DME), weight loss, compressive strength, tensile strength, flexural strength, cleavage strength and stress-strain relationships of plain concrete specimens suffering from freeze-thaw cycles were measured. The experimental results showed that the strength decreased as the freeze-thaw cycles were repeated. A c...

  6. Thermal cycling influence on microstructural characterization of alloys with high nickel content

    International Nuclear Information System (INIS)

    Abrudeanu, M.; Gradin, O.; Vulpe, S. C.; Ohai, D.

    2013-01-01

    The IV nuclear energy generation systems are aimed at making revolutionary improvements in economics, safety and reliability, and sustainability. To achieve these goals, Generation IV systems will operate at higher temperatures and in higher radiation fields. This paper shows the thermal cycling influences on microstructure and hardness of nickel based alloys: Incoloy 800 HT and Inconel 617. These alloys were meekly at a thermal cycling of 25, 50, 75 and 100 cycles. The temperature range of a cycle was between 400 O C and 700 O C. Nickel base alloys develop their properties by solid solution and/or precipitation strengthening. (authors)

  7. MOTHER MK II: An advanced direct cycle high temperature gas reactor

    International Nuclear Information System (INIS)

    Hart, R.S.; Kendall, J.M.; Marsden, B.J.

    2003-01-01

    The MOTHER (MOdular Thermal HElium Reactor) power plant concepts employ high temperature gas reactors utilizing TRISO fuel, graphite moderator, and helium coolant, in combination with a direct Brayton cycle for electricity generation. The helium coolant from the reactor vessel passes through a Power Conversion Unit (PCU), which includes a turbine-generator, recuperator, precooler, intercooler and turbine-compressors, before being returned to the reactor vessel. The PCU substitutes for the reactor coolant system pumps and steam generators and most of the Balance Of Plant (BOP), including the steam turbines and condensers, employed by conventional nuclear power plants utilizing water cooled reactors. This provides a compact, efficient, and relatively simple plant configuration. The MOTHER MK I conceptual design, completed in the 1987 - 1989 time frame, was developed to economically meet the energy demands for extracting and processing heavy oil from the tar sands of western Canada. However, considerable effort was made to maximize the market potential beyond this application. Consistent with the remote and very high labour rate environment in the tar sands region, simplification of maintenance procedures and facilitation of 'change-out' in lieu of in situ repair was a design focus. MOTHER MK I had a thermal output of 288 MW and produced 120 MW electrical when operated in the electricity only production mode. An annular Prismatic reactor core was utilized, largely to minimize day-to-day operations activities. Key features of the power conversion system included two Power Conversion Units (144 MW th each), the horizontal orientation of all rotating machinery and major heat exchangers axes, high speed rotating machinery (17,030 rpm for the turbine-compressors and 10,200 rpm for the power turbine-generator), gas (helium) bearings for all rotating machinery, and solid state frequency conversion from 170 cps (at full power) to the grid frequency. Recognizing that the on

  8. The north-south asymmetry of solar filaments separately at low and high latitudes in solar cycle 23

    International Nuclear Information System (INIS)

    Kong De-Fang; Qu Zhi-Ning; Guo Qiao-Ling

    2015-01-01

    We present the results of a study on the north-south asymmetry of solar filaments at low (<50°) and high (>60°) latitudes using daily filament numbers from January 1998 to November 2008 (solar cycle 23). It is found that the northern hemisphere is dominant at low latitudes for cycle 23. However, a similar asymmetry does not occur for solar filaments at high latitudes. The present study indicates that the hemispheric asymmetry of solar filaments at high latitudes in a cycle appears to have little connection with that at low latitudes. Our results support that the observed magnetic fields at high latitudes include two components: one comes from the emergence of the magnetic fields from the solar interior and the other comes from the drift of the magnetic activity at low latitudes. (research papers)

  9. Hierarchical N-Rich Carbon Sponge with Excellent Cycling Performance for Lithium-Sulfur Battery at High Rates.

    Science.gov (United States)

    Zhen, Mengmeng; Wang, Juan; Wang, Xin; Wang, Cheng

    2018-04-17

    Lithium-sulfur batteries (LSBs) are receiving extensive attention because of their high theoretical energy density. However, practical applications of LSBs are still hindered by their rapid capacity decay and short cycle life, especially at high rates. Herein, a highly N-doped (≈13.42 at %) hierarchical carbon sponge (HNCS) with strong chemical adsorption for lithium polysulfide is fabricated through a simple sol-gel route followed by carbonization. Upon using the HNCS as the sulfur host material in the cathode and an HNCS-coated separator, the battery delivers an excellent cycling stability with high specific capacities of 424 and 326 mA h g -1 and low capacity fading rates of 0.033 % and 0.030 % per cycle after 1000 cycles under high rates of 5 and 10 C, respectively, which are superior to those of other reported carbonaceous materials. These impressive cycling performances indicate that such a battery could promote the practical application prospects of LSBs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Range of monthly mean hourly land surface air temperature diurnal cycle over high northern latitudes

    Science.gov (United States)

    Wang, Aihui; Zeng, Xubin

    2014-05-01

    Daily maximum and minimum temperatures over global land are fundamental climate variables, and their difference represents the diurnal temperature range (DTR). While the differences between the monthly averaged DTR (MDTR) and the range of monthly averaged hourly temperature diurnal cycle (RMDT) are easy to understand qualitatively, their differences have not been quantified over global land areas. Based on our newly developed in situ data (Climatic Research Unit) reanalysis (Modern-Era Retrospective analysis for Research and Applications) merged hourly temperature data from 1979 to 2009, RMDT in January is found to be much smaller than that in July over high northern latitudes, as it is much more affected by the diurnal radiative forcing than by the horizontal advection of temperature. In contrast, MDTR in January is comparable to that in July over high northern latitudes, but it is much larger than January RMDT, as it primarily reflects the movement of lower frequency synoptic weather systems. The area-averaged RMDT trends north of 40°N are near zero in November, December, and January, while the trends of MDTR are negative. These results suggest the need to use both the traditional MDTR and RMDT suggested here in future observational and modeling studies. Furthermore, MDTR and its trend are more sensitive to the starting hour of a 24 h day used in the calculations than those for RMDT, and this factor also needs to be considered in model evaluations using observational data.

  11. Experimental Investigation on High-Cycle Fatigue of Inconel 625 Superalloy Brazed Joints

    Science.gov (United States)

    Chen, Jianqiang; Demers, Vincent; Turner, Daniel P.; Bocher, Philippe

    2018-04-01

    The high-cycle fatigue performance and crack growth pattern of transient liquid phase-brazed joints in a nickel-based superalloy Inconel 625 were studied. Assemblies with different geometries and types of overlaps were vacuum-brazed using the brazing paste Palnicro-36M in conditions such as to generate eutectic-free joints. This optimal microstructure provides the brazed assemblies with static mechanical strength corresponding to that of the base metal. However, eutectic micro-constituents were observed in the fillet region of the brazed assembly due to an incomplete isothermal solidification within this large volume of filler metal. The fatigue performance increased significantly with the overlap distance for single-lap joints, and the best performance was found for double-lap joints. It was demonstrated that these apparent changes in fatigue properties according to the specimen geometry can be rationalized when looking at the fatigue data as a function of the local stress state at the fillet radii. Fatigue cracks were nucleated from brittle eutectic phases located at the surface of the fillet region. Their propagation occurred through the bimodal microstructure of fillet and the diffusion region to reach the base metal. High levels of crack path tortuosity were observed, suggesting that the ductile phases found in the microstructure may act as a potential crack stopper. The fillet region must be considered as the critical region of a brazed assembly for fatigue applications.

  12. High-cycle fatigue properties of small-bore socket-welded pipe joint

    International Nuclear Information System (INIS)

    Maekawa, Akira; Noda, Michiyasu; Suzuki, Michiaki

    2009-01-01

    Piping and equipment in nuclear power plants are structures including many welded joints. Reliability of welded joints is one of high-priority issues to improve the safety of nuclear power plants. However, occurrence of fatigue failures in small-bore socket-welded pipe joints by high-cycle vibrations is still reported. In this study, fatigue experiments on a socket-welded joint of austenitic stainless steel pipe was conducted under excitation conditions similar to those in actual plants to investigate vibration characteristics and fatigue strength. It was found that the natural frequency of pipe with socket-welded joint gradually decreased as fatigue damage developed, according to the Miner rule for fatigue life evaluation. The results indicate that the fatigue life of the welded pipe joint could be estimated by monitoring the decreasing ratio of the natural frequency of the pipe. The evaluation of decreasing ratio of the natural frequency in addition to fatigue damage evaluation by the Miner rule could enhance the accuracy of fatigue life evaluation. (author)

  13. Autophagic flux is highly active in early mitosis and differentially regulated throughout the cell cycle.

    Science.gov (United States)

    Li, Zhiyuan; Ji, Xinmiao; Wang, Dongmei; Liu, Juanjuan; Zhang, Xin

    2016-06-28

    Mitosis is a fast process that involves dramatic cellular remodeling and has a high energy demand. Whether autophagy is active or inactive during the early stages of mitosis in a naturally dividing cell is still debated. Here we aimed to use multiple assays to resolve this apparent discrepancy. Although the LC3 puncta number was reduced in mitosis, the four different cell lines we tested all have active autophagic flux in both interphase and mitosis. In addition, the autophagic flux was highly active in nocodazole-induced, double-thymidine synchronization released as well as naturally occurring mitosis in HeLa cells. Multiple autophagy proteins are upregulated in mitosis and the increased Beclin-1 level likely contributes to the active autophagic flux in early mitosis. It is interesting that although the autophagic flux is active throughout the cell cycle, early mitosis and S phase have relatively higher autophagic flux than G1 and late G2 phases, which might be helpful to degrade the damaged organelles and provide energy during S phase and mitosis.

  14. Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd2@C79N.

    Science.gov (United States)

    Hu, Ziqi; Dong, Bo-Wei; Liu, Zheng; Liu, Jun-Jie; Su, Jie; Yu, Changcheng; Xiong, Jin; Shi, Di-Er; Wang, Yuanyuan; Wang, Bing-Wu; Ardavan, Arzhang; Shi, Zujin; Jiang, Shang-Da; Gao, Song

    2018-01-24

    An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M 2 @C 79 N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd 2 @C 79 N for the first time. This molecular magnet with a collective high-spin ground state (S = 15/2) generated by strong magnetic coupling (J Gd-Rad = 350 ± 20 cm -1 ) has been unambiguously validated by magnetic susceptibility experiments. Gd 2 @C 79 N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover's searching algorithm proposed by Leuenberger and Loss.

  15. Characterization of high cycle fatigue behavior of a new generation aluminum lithium alloy

    International Nuclear Information System (INIS)

    De, P.S.; Mishra, R.S.; Baumann, J.A.

    2011-01-01

    Highlights: → Effect of microstructure on fatigue fracture of an advanced Al-Li alloy was studied in detail. → Preferential crack propagation in T3 state at specific orientations was analyzed. → Fatigue crack propagation difference between T3 and T8 tempers and friction stir welded condition was rationalized. → The effect of grain size on fatigue life for T3 and T8 tempers was justified based on current theories. → Delamination in T3 and T8 tempers was rationalized using microstructural analysis and FEA simulation. - Abstract: The high cycle fatigue life characteristics of an Al-Li alloy were studied as a function of microstructure. While for the parent microstructure fatigue life decreased as grain size increased, no such effect was noted at high stresses. This decrease in fatigue life was correlated with lower crack initiation life due to small crack effect. Under multiaxial stress conditions, the alloy exhibited intergranular cracking. The cross-linking of intergranular cracks (in the T8 condition) caused a further deterioration in fatigue life. Additionally, planar slip movements (in the T3 condition) in stage I crack propagation were observed. Slip planarity depended on both the sample texture and the nature of the precipitates. Fractographic and textural evidence is presented.

  16. Bioinspired Polymeric Photonic Crystals for High Cycling pH-Sensing Performance.

    Science.gov (United States)

    Fei, Xiang; Lu, Tao; Ma, Jun; Wang, Wanlin; Zhu, Shenmin; Zhang, Di

    2016-10-12

    Artificial photonic crystals (PCs) have been extensively studied to improve the sensing performance of poly(acrylic acid) (PAAc), as it can transform the PAAc volume change into optical signal which is easier to read. Nevertheless, these PCs are limited by the monostructure. We herein developed new photonic crystals (PCs) by coating acrylic acid and acrylamide (AAm) via in situ copolymerization onto Papilio paris wings having hierarchical, lamellar structure. Our PCs exhibited high performance of color tunability to environmental pH, as detected by reflectance spectra and visual observation. The introduction of AAm into the system created covalent bonding which robustly bridged the polymer with the wings, leading to an accurate yet broad variation of reflection wavelength to gauge environmental pH. The reflection wavelength can be tailored by the refractive index of the lamellar interspacing due to the swelling/deswelling of the polymer. The mechanism is not only supported by experimenta but proved by finite-difference time-domain simulation. Moreover, It is worth noting that the covalent bonding has provided the PCs-based pH sensor with high cycling performance, implying great potential in practical applications. The simple fabrication process is applicable to the development of a wide variety of stimuli-responsive PCs taking advantage of other polymers.

  17. Characterization of high cycle fatigue behavior of a new generation aluminum lithium alloy

    Energy Technology Data Exchange (ETDEWEB)

    De, P.S. [Center for Friction Stir Processing, Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Mishra, R.S., E-mail: rsmishra@mst.edu [Center for Friction Stir Processing, Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Baumann, J.A. [Boeing Company, St. Louis, MO 631666 (United States)

    2011-09-15

    Highlights: {yields} Effect of microstructure on fatigue fracture of an advanced Al-Li alloy was studied in detail. {yields} Preferential crack propagation in T3 state at specific orientations was analyzed. {yields} Fatigue crack propagation difference between T3 and T8 tempers and friction stir welded condition was rationalized. {yields} The effect of grain size on fatigue life for T3 and T8 tempers was justified based on current theories. {yields} Delamination in T3 and T8 tempers was rationalized using microstructural analysis and FEA simulation. - Abstract: The high cycle fatigue life characteristics of an Al-Li alloy were studied as a function of microstructure. While for the parent microstructure fatigue life decreased as grain size increased, no such effect was noted at high stresses. This decrease in fatigue life was correlated with lower crack initiation life due to small crack effect. Under multiaxial stress conditions, the alloy exhibited intergranular cracking. The cross-linking of intergranular cracks (in the T8 condition) caused a further deterioration in fatigue life. Additionally, planar slip movements (in the T3 condition) in stage I crack propagation were observed. Slip planarity depended on both the sample texture and the nature of the precipitates. Fractographic and textural evidence is presented.

  18. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. 75 FR 51239 - Application(s) for Duty-Free Entry of Scientific Instruments

    Science.gov (United States)

    2010-08-19

    ... operation, i.e., scanning tunneling microscopy and atomic force microscopy. Justification for Duty-Free... Microscope System for Application in High Magnetic Fields. Manufacturer: Omicron Nanotechnology, Germany...

  20. Cycling to high school in Toronto, Ontario, Canada: Exploration of school travel patterns and attitudes by gender

    NARCIS (Netherlands)

    Wittmann, K.; Savan, B.; Ledsham, T.; Liu, G.; Lay, J.

    2015-01-01

    This study surveyed attitudes, behaviors, social norms, and perceived control among the populations of students at three high schools in downtown Toronto, Ontario, Canada. The results showed a pattern of hesitancy to cycle on the part of female high school students compared with their male

  1. The Effect of Recycling Education on High School Students' Conceptual Understanding about Ecology: A Study on Matter Cycle

    Science.gov (United States)

    Ugulu, Ilker; Yorek, Nurettin; Baslar, Suleyman

    2015-01-01

    The objective of this study is to analyze and determine whether a developed recycling education program would lead to a positive change in the conceptual understanding of ecological concepts associated with matter cycles by high school students. The research was conducted on 68 high school 10th grade students (47 female and 21 male students). The…

  2. Synthesis of realistic driving cycles with high accuracy and computational speed, including slope information

    NARCIS (Netherlands)

    Silvas, E.; Hereijgers, K.; Peng, Huei; Hofman, T.; Steinbuch, M.

    2016-01-01

    This paper describes a new method to synthesize driving cycles, where not only the velocity is considered, yet also the road slope information of the real-world measured driving cycle. Driven by strict emission regulations and tight fuel targets, hybrid or electric vehicle manufacturers aim to

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

    Science.gov (United States)

    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

  4. Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling

    Science.gov (United States)

    Zeng, Fan Wen; Wang, Hong; Lin, Hua-Tay

    2013-07-01

    Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 × 105 to 7 × 105 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 108 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. Furthermore, involved fatigue and failure mechanisms were investigated using scanning acoustic microscope and scanning electron microscope. The extensive cracks and porous regions were revealed across the PZT layers on the cross sections of a failed actuator. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to test and monitor the behavior of PZT stacks.

  5. A model for life predictions of nickel-base superalloys in high-temperature low cycle fatigue

    Science.gov (United States)

    Romanoski, Glenn R.; Pelloux, Regis M.; Antolovich, Stephen D.

    1988-01-01

    Extensive characterization of low-cycle fatigue damage mechanisms was performed on polycrystalline Rene 80 and IN100 tested in the temperature range from 871 to 1000 C. Low-cycle fatigue life was found to be dominated by propagation of microcracks to a critical size governed by the maximum tensile stress. A model was developed which incorporates a threshold stress for crack extension, a stress-based crack growth expression, and a failure criterion. The mathematical equivalence between this mechanistically based model and the strain-life low-cycle fatigue law was demonstrated using cyclic stress-strain relationships. The model was shown to correlate the high-temperature low-cycle fatigue data of the different nickel-base superalloys considered in this study.

  6. Application of a high-repetition-rate laser diagnostic system for single-cycle-resolved imaging in internal combustion engines.

    Science.gov (United States)

    Hult, Johan; Richter, Mattias; Nygren, Jenny; Aldén, Marcus; Hultqvist, Anders; Christensen, Magnus; Johansson, Bengt

    2002-08-20

    High-repetition-rate laser-induced fluorescence measurements of fuel and OH concentrations in internal combustion engines are demonstrated. Series of as many as eight fluorescence images, with a temporal resolution ranging from 10 micros to 1 ms, are acquired within one engine cycle. A multiple-laser system in combination with a multiple-CCD camera is used for cycle-resolved imaging in spark-ignition, direct-injection stratified-charge, and homogeneous-charge compression-ignition engines. The recorded data reveal unique information on cycle-to-cycle variations in fuel transport and combustion. Moreover, the imaging system in combination with a scanning mirror is used to perform instantaneous three-dimensional fuel-concentration measurements.

  7. Multi-Speed Transmission For Commercial Delivery Medium Duty PEDVs

    Energy Technology Data Exchange (ETDEWEB)

    Chavdar, Bulent [Eaton Corp., Menomonee Falls, WI (United States)

    2017-12-31

    Successful completion of the proposed project will set a course for improving quality of life by overcoming key challenges in the gearbox for commercial-delivery, medium-duty, plug-in electric drive vehicles: It will reduce US dependency on foreign oil through the use of electric driven propulsion instead of fuel driven. It will reduce health risks by replacing tailpipe emissions in densely populated city centers. Finally, it will improve the performance-cost basis to meet or exceed the expectations of the targeted medium duty vehicle fleet owners and the independent customers. The proposed multi-speed transmission will narrow motor operation to the peak efficiency region, thereby increasing the electric powertrain efficiency to help close the range gap. Further, it will enhance customer satisfaction by improving vehicle acceleration, top speed and gradeability over the baseline. The project was conducted in three budget periods: In BP1: Technology Development, High-level vehicle powertrain models were used to optimize candidate transmission architectures and ratios along with a variety of traction motor characteristics for concept selection. The detailed driveline designs and component dynamics were investigated to meet medium-duty EV requirements; In BP2: Technology Development and Prototype Demonstration, The modeling and simulations with multi-speed transmissions were extended to other MD and HD EV platforms. Clean sheet design of a compact, lightweight, flexible, and modular, four-speed transmission was completed. Development of novel shifting and controls strategies were started and procurement of the prototype transmission and the controller hardware was begun; In BP3: Technology Integration, Testing, and Demonstration, Prototyping the four-speed automated mechanical transmission was completed. The transmission controls system and software development and preliminary gearbox dyno tests were done at Eaton. ORNL conducted integrated powertrain HIL tests. One

  8. High electrochemical energy storage in self-assembled nest-like CoO nanofibers with long cycle life

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Atin; Maiti, Sandipan [CSIR-Central Glass & Ceramic Research Institute, Fuel Cell & Battery Division (India); Sreemany, Monjoy [CSIR-Central Glass & Ceramic Research Institute, Advanced Mechanical and Materials Characterization Division (India); Mahanty, Sourindra, E-mail: mahanty@cgcri.res.in [CSIR-Central Glass & Ceramic Research Institute, Fuel Cell & Battery Division (India)

    2016-04-15

    Developing efficient electrode material is essential to keep pace with the demand for high energy density together with high power density and long cycle life in next generation energy storage devices. Herein, we report the electrochemical properties of hydrothermally synthesized CoO nanofibers of diameter 30–80 nm assembled in a nest-like morphology which showed a very high reversible lithium storage capacity of 2000 mA h g{sup −1} after 600 cycles at 0.1 mA cm{sup −2} as lithium-ion battery anode. Systematic investigation by ex situ transmission electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and impedance spectroscopy at different cycling stages indicated that the extraordinary performance could be related to an enhancement in the Co{sup 2+}↔Co{sup x+} (2 < x ≤ 3) redox process in addition to the commonly believed structural and morphological evolution during cycling favoring generation of large number of accessible active sites for lithium insertion. Further, when examined as a supercapacitor electrode in 1.0 M KOH, a capacitance of 1167 F g{sup −1} is achieved from these 1D CoO nanofibers after 10,000 charge discharge cycles at a high current density of 5 A g{sup −1} demonstrating good application potential.Graphical AbstractNest-like CoO nanofibers showed a reversible lithium storage capacity of 2000 mA h g{sup −1} after 600 cycles as LIB anode and a capacitance of 1167 F g{sup −1} after 10,000 cycles as electrochemical supercapacitor.

  9. Synthesis of hierarchical porous honeycomb carbon for lithium-sulfur battery cathode with high rate capability and long cycling stability

    International Nuclear Information System (INIS)

    Qu, Yaohui; Zhang, Zhian; Zhang, Xiahui; Ren, Guodong; Wang, Xiwen; Lai, Yanqing; Liu, Yexiang; Li, Jie

    2014-01-01

    Highlights: • A novel HPHC was prepared by a simple template process. • The HPHC as matrix to load sulfur for Lithium-Sulfur battery cathodes. • S-HPHC cathode shows high rate capability and long cycling stability. • The sulfur-HPHC composite presents electrochemical stability up to 300 cycles at 1.5 C. - Abstract: Sulfur has a high specific capacity of 1675 mAh g −1 as lithium battery cathode, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a novel hierarchical porous honeycomb carbon (HPHC) for lithium-sulfur battery cathode with effective trapping of polysulfides. The HPHC was prepared by a simple template process, and a sulfur-carbon composite based on HPHC was synthesized for lithium-sulfur batteries by a melt-diffusion method. It is found that the elemental sulfur was dispersed inside the three-dimensionally hierarchical pores of HPHC based on the analyses. Electrochemical tests reveal that the sulfur-HPHC composite shows high rate capability and long cycling stability as cathode materials. The sulfur-HPHC composite with sulfur content of 66.3 wt% displays an initial discharge capacity of 923 mAh g −1 and a reversible discharge capacity of 564 mAh g −1 after 100 cycles at 2 C charge-discharge rate. In particular, the sulfur-HPHC composite presents a long term cycling stability up to 300 cycles at 1.5 C. The results illustrate that the electrochemical reaction constrained inside the interconnected macro/meso/micropores of HPHC would be the dominant factor for the excellent high rate capability and long cycling stability of the sulfur cathode, and the three-dimensionally honeycomb carbon network would be a promising carbon matrix structure for lithium-sulfur battery cathode

  10. Proof-of-principle of high-fidelity coupled CRUD deposition and cycle depletion simulation

    International Nuclear Information System (INIS)

    Walter, Daniel J.; Kendrick, Brian K.; Petrov, Victor; Manera, Annalisa; Collins, Benjamin; Downar, Thomas

    2015-01-01

    A multiphysics framework for the high-fidelity simulation of CRUD deposition is developed to better understand the coupled physics and their respective feedback mechanisms. This framework includes the primary physics of lattice depletion, computational fluid dynamics, and CRUD chemistry. The three physics are coupled together via the operator-splitting technique, where predictor–corrector and fixed-point iteration schemes are utilized to converge the nonlinear solution. High-fidelity simulations may provide a means to predict and assess potential operating issues, including CRUD induced power shift and CRUD induced localized corrosion, known as CIPS and CILC, respectively. As a proof-of-principle, a coupled 500-day cycle depletion simulation of a pressurized water reactor fuel pin cell was performed using the coupled code suite; a burnup of 31 MWd/kgHM was reached. The simulation recreated the classic striped CRUD pattern often seen on pulled fuel rods containing CRUD. It is concluded that the striping is caused by the flow swirl induced by spacer grid mixing vanes. Two anti-correlated effects contribute to the striping: (1) the flow swirl yields significant azimuthal temperature variations, which impact the locations where CRUD deposits, and (2) the flow swirl is correlated to increased shear stress along the cladding surface and subsequent erosion of the CRUD layer. The CIPS condition of the core is concluded to be primarily controlled by lithium tetraborate precipitation, referred to as boron hideout, which occurs in regions experiencing subcooled nucleate boiling as soluble boron and lithium species reach their solubility limit within the CRUD layer. Subsequently, a localized reduction in power occurs due to the high neutron absorption cross section of boron-10

  11. Life cycle assessment of small-scale high-input Jatropha biodiesel production in India

    International Nuclear Information System (INIS)

    Pandey, Krishan K.; Pragya, Namita; Sahoo, P.K.

    2011-01-01

    Highlights: → NEB and NER of high input Jatropha biodiesel system was higher than those of low input. → These values further increase on including the energy content of the co-products, and in the further years. → Maximum energy use was during oil extraction, followed by oil processing and fertilizer use. → Allocation of resources at right time and with proper care increase the overall system productivity. -- Abstract: In the current scenario of depleting energy resources, increasing food insecurity and global warming, Jatropha has emerged as a promising energy crop for India. The aim of this study is to examine the life cycle energy balance for Jatropha biodiesel production and greenhouse gas emissions from post-energy use and end combustion of biodiesel, over a period of 5 years. It's a case specific study for a small scale, high input Jatropha biodiesel system. Most of the existing studies have considered low input Jatropha biodiesel system and have used NEB (Net energy balance i.e. difference of energy output and energy input) and NER (Net energy ratio i.e. ratio of energy output to energy input) as indicators for estimating the viability of the systems. Although, many of them have shown these indicators to be positive, yet the values are very less. The results of this study, when compared with two previous studies of Jatropha, show that the values for these indicators can be increased to a much greater extent, if we use a high input Jatropha biodiesel system. Further, when compared to a study done on palm oil and Coconut oil, it was found even if the NEB and NER of biodiesel from Jatropha were lesser in comparison to those of Palm oil and Coconut oil, yet, when energy content of the co-products were also considered, Jatropha had the highest value for both the indicators in comparison to the rest two.

  12. Emissions from Medium-Duty Conventional and Diesel-Electric Hybrid Vehicles; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Ragatz, A.; Duran, A.; Thornton, M.; Walkowicz, K.

    2014-04-02

    This presentation discusses the results of emissions testing for medium-duty conventional and diesel-electric hybrid vehicles. Testing was based on a field evaluation approach that utilized the Fleet DNA drive cycle database and NREL’s Renewable Fuels and Lubricants (ReFUEL) Laboratory chassis dynamometer. Vehicles tested included parcel delivery (Class 6 step vans), beverage delivery (Class 8 tractors), and parcel delivery (Class 7 box trucks) vehicles, all with intended service class medium/heavy heavy-duty diesel (MHDD).
    Results for fuel economy and tailpipe NOx emissions included: diesel hybrid electric vehicles showed an average fuel economy advantage on identified test cycles: Class 6 Step Vans: 26%; Class 7 Box Trucks: 24.7%; Class 8 Tractors: 17.3%. Vehicle miles traveled is an important factor in determining total petroleum and CO2 displacement. Higher NOx emissions were observed over some test cycles: highly drive cycle dependent; engine-out differences may result from different engine operating point; and selective catalyst reduction temperature may play a role, but does not explain the whole story.

  13. Crack growth behaviour of aluminium wrought alloys in the Very High Cycle Fatigue regime

    Directory of Open Access Journals (Sweden)

    Bülbül Fatih

    2018-01-01

    Full Text Available Investigations have shown that in the regime of Very High Cycle Fatigue (VHCF “natural” crack initiation often takes place underneath the material surface leading to crack propagation without contact to atmospheric components. In order to elucidate the environmental damage contribution and its effect on the VHCF long crack propagation, fatigue experiments with alternating environment (vacuum and laboratory air were performed. An ultrasonic fatigue testing system (USFT equipped with a small vacuum chamber was applied that enables the in-situ examination of the long fatigue crack propagation at a resonance frequency of about 20 kHz by using a long distance microscope. By means of the Focused-Ion-Beam technique, micro-notches were prepared in the USFT specimens. The tests were carried out on the aluminium alloys EN-AW 6082 and 5083 in different conditions. It has been found that the atmosphere has a significant influence on the VHCF long crack propagation which manifests itself in the crack path as well as in the crack growth rates. Because of pronounced single sliding in vacuum, shear-stress-controlled crack propagation was detected whereas in laboratory air normal-stress-controlled crack propagation occurred. Furthermore, it has been proven that the secondary precipitation state of the aluminium alloy significantly influences the VHCF long crack propagation in vacuum.

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

    Science.gov (United States)

    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.

  15. Study on high-cycle fatigue behavior of candidate stainless steels for SCWR

    International Nuclear Information System (INIS)

    Xiong Ru; Zhao Yuxiang; Zhang Qiang; Wang Hao; Tang Rui; Qiao Yingjie

    2013-01-01

    The fatigue experiments of commerce stainless steels including 347, 316Ti and 310 were conducted under bending and rotating loadings. The environments were at room temperature (RT) as well as at 550℃ in air. The fracture morphology was observed by SEM, and the S-N curves were processed according to the experimental data. The results indicate the fatigue limited stresses for the 3 stainless steels were in the order of 347 < 316Ti < 310, which consistent with the order of their tensile strength. Elevated temperature would accelerate the oxidation and therefore the fatigue life would decrease, among them 347 was more sensitive to temperature with the maximum decreasing tendency. All the 3 stainless steels have good resistance to high cycle fatigue when comparing their experimental data with the calculated value from the empirical formula. The fracture morphology presents areas of crack initiation, crack growth and fracture, the width of fatigue ripples is about 1 μm, the fracture area has much dimples, and 347 presents much cavities of different sizes in dimples. (authors)

  16. Economic evaluation of the steam-cycle high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    1983-07-01

    The High Temperature Gas-Cooled Reactor is unique among current nuclear technologies in its ability to generate energy in temperature regimes previously limited to fossil fuels. As a result, it can offer commercial benefits in the production of electricity, and at the same time, expand the role of nuclear energy to the production of process heat. This report provides an evaluation of the HTGR-Steam Cycle (SC) system for the production of baseloaded electricity, as well as cogenerated electricity and process steam. In each case the HTGR-SC system has been evaluated against appropriate competing technologies. The computer code which was developed for this evaluation can be used to present the analyses on a cost of production or cash flow basis; thereby, presenting consistent results to a utility, interested in production costs, or an industrial steam user or third party investor, interested in returns on equity. Basically, there are two economic evaluation methodologies which can be used in the analysis of a project: (1) minimum revenue requirements, and (2) discounted cash flow

  17. FACTORS THAT INFLUENCE IN SEDENTARY LIFESTYLE OF STUDENTS OF FOURTH CYCLE OF A PUBLIC HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    Carlos Álvarez Bogantes

    2015-08-01

    Full Text Available There is sufficient evidence to say that women as they move into the education system to reduce physical activity levels of sedentary lifestyle that put them at higher risk for non-communicable diseases. This led to determine the reasons for the inactivity of a group of fourth cycle. In order to address this problem, a qualitative design using focus groups and depth interviews was used, applied to30 women of high school participated. The results indicate that the participants are unaware of the benefits that can give them an active life, possibly affecting their movement behavior. A key element that have expressed is little impact of physical education classes when promoting lifestyles movement of the participants in this study, especially for ignoring the needs and barriers that students have. Become clear that the sport orientation of physical education classes and lack the skills to participate in activities successfully, sedentary activities of friends, the attitudes of parents; curriculum and lack of facilities also have significant impact in the studied group.

  18. Challenges in high temperature low cycle fatigue testing of metallic materials

    International Nuclear Information System (INIS)

    Sandhya, R.; Valsan, M.; Bhanu Sankara Rao, K.

    2007-01-01

    The evaluation of the high strain Low Cycle Fatigue properties of structural materials is an involved and complicated procedure requiring skill and diligence from the experimentalist. This presentation describes the various testing methods to evaluate the LCF properties of structural materials, the complexities involved and some solutions to exacting requirements, not covered by the testing procedure standards. The basic components of servo-hydraulic fatigue testing machines is described, as are the calibration and maintenance procedures. Results of LCF tests conducted at the authors' laboratory on AISI 316L(N) stainless steel and Mod.9Cr-1Mo ferritic steel are described. The complications in total strain controlled testing of weld joints is brought out and soft zone development in Mod. 9Cr-1Mo ferritic steel is described. The special requirements for testing in environmental chambers is a challenging task. In-house chambers, designed to carry out testing in dynamic sodium environment is highlighted. These chambers have provision to accommodate extensometers for strain measurements, and also house all the safety instrumentation needed to carry out to mechanical testing in dynamic sodium environment. The variation of LCF results as a function of specimen geometry is examined. The various failure criteria adopted by laboratories in different countries are also touched upon. (author)

  19. Ignition of deuterium based fuel cycles in a high beta system

    International Nuclear Information System (INIS)

    Hirano, K.

    1987-01-01

    A steady state self-consistent plasma modeling applied to a system having close to unity, such as FRC or like, is found to be quite effective in solving the problems independently of any anomalous process and proves the existence of ignited state of deuterium based fuel cycles. The temperature ranges that the plasma falls into ignited state are obtained as a function of relative feeding rates of tritium and 3 He to deuterium's. We find pure DD cycle will not ignite so that 3 He or/and tritium must be added as catalyzer to achieve ignition. Standing on the points to construct a cleaner system yielding smaller amount of 14 MeV neutrons and to burn the fuel in steady state for long periods of time, we have confirmed superiority of the complex composed of the master reactor of 3 He-Cat.D cycle (catalyzed DD cycle reinjecting only fusion produced 3 He) and the satellite reactor of 3 He enriched D 3 He cycle. In case storage of tritium for 3 He by β - decay is turned out not to be allowed environmentally, we may utilize conventional catalyzed DD cycle although 14 MeV neutron yields will be increased by 35 % over the complex. It is demonstrated that advanced fuel cycle reactors can be very simple in constructions and compact in size such that the field strength and the plasma volume of the order of JT-60's may be enough for 1000 MW power plant. (author)

  20. A New Multiaxial High-Cycle Fatigue Criterion Based on the Critical Plane for Ductile and Brittle Materials

    Science.gov (United States)

    Wang, Cong; Shang, De-Guang; Wang, Xiao-Wei

    2015-02-01

    An improved high-cycle multiaxial fatigue criterion based on the critical plane was proposed in this paper. The critical plane was defined as the plane of maximum shear stress (MSS) in the proposed multiaxial fatigue criterion, which is different from the traditional critical plane based on the MSS amplitude. The proposed criterion was extended as a fatigue life prediction model that can be applicable for ductile and brittle materials. The fatigue life prediction model based on the proposed high-cycle multiaxial fatigue criterion was validated with experimental results obtained from the test of 7075-T651 aluminum alloy and some references.

  1. Lightweight Composite Materials for Heavy Duty Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Pruez, Jacky; Shoukry, Samir; Williams, Gergis; Shoukry, Mark

    2013-08-31

    The main objective of this project is to develop, analyze and validate data, methodologies and tools that support widespread applications of automotive lightweighting technologies. Two underlying principles are guiding the research efforts towards this objective: • Seamless integration between the lightweight materials selected for certain vehicle systems, cost-effective methods for their design and manufacturing, and practical means to enhance their durability while reducing their Life-Cycle-Costs (LCC). • Smooth migration of the experience and findings accumulated so far at WVU in the areas of designing with lightweight materials, innovative joining concepts and durability predictions, from applications to the area of weight savings for heavy vehicle systems and hydrogen storage tanks, to lightweighting applications of selected systems or assemblies in light–duty vehicles.

  2. Life Cycle Assessment of a Highly Diverse Vegetable Multi-Cropping System in Fengqiu County, China

    Directory of Open Access Journals (Sweden)

    Li Li

    2018-03-01

    Full Text Available Agricultural biodiversity usually leads to greater sustainability in production practices. To understand the environmental implications of the development of village-level multi-cropping in rural China, we compared the environmental impact of a highly diverse vegetable multi-cropping system to a conventional wheat/maize rotation system based on the method of life cycle assessment (LCA. Using household level cultivation data, this study examined the gate-to-gate environmental impacts of on-site cultivation practices relating to the production of 10,000 nutrient equivalent units. Results show that vegetable multi-cropping resulted in decreased average land requirement, and diesel, water and electricity usage by 69.8%, 62.2%, 71.7%, and 63.4%, respectively, while average nitrogen (Total N, phosphorus (P2O5, and potassium (K2O usage in vegetable multi-cropping systems decreased by 16.3%, 42.1%, and 75.8%, respectively. Additional corresponding effects led to a decrease in the total global warming, eutrophication, and acidification potentials from external inputs by 21.6%, 16.7%, and 16.2% of the entire system, respectively. Moreover, the midpoint human toxicity potential from pesticide usage of the vegetable multi-cropping system was lower than that of the conventional system. However, the midpoint eco-toxicity potential from pesticide usage was higher due to certain highly toxic substances, and both human and eco-toxicity potentials from heavy metals were all higher by a few orders of magnitudes. Thus, to mitigate these detrimental consequences, some related measures are proposed for sustainable practices in the future implementation of multi-cropping systems.

  3. Is high-intensity interval cycling feasible and more beneficial than continuous cycling for knee osteoarthritic patients? Results of a randomised control feasibility trial.

    Science.gov (United States)

    Keogh, Justin W; Grigg, Josephine; Vertullo, Christopher J

    2018-01-01

    Knee osteoarthritis (OA) patients often suffer joint pain and stiffness, which contributes to negative changes in body composition, strength, physical performance (function), physical activity and health-related quality of life. To reduce these symptoms and side effects of knee OA, moderate-intensity continuous training (MICT) cycling is often recommended. While resistance training is considered the optimal form of training to improve sarcopenic outcomes, it imposes higher joint loads and requires supervision, either initially or continuously by trained exercise professionals. Therefore, this pilot study sought to gain some insight into the feasibility and potential benefits of high-intensity interval training (HIIT) cycling as an alternative exercise option to MICT cycling for individuals with knee OA. Twenty-seven middle-aged and older adults with knee OA were randomly allocated to either MICT or HIIT, with both programs involving four unsupervised home-based cycling sessions (∼25 min per session) each week for eight weeks. Feasibility was assessed by enrolment rate, withdrawal rate, exercise adherence and number of adverse effects. Efficacy was assessed by health-related quality of life (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Lequesne index), physical function (Timed Up and Go (TUG), Sit to Stand (STS) and preferred gait speed) and body composition (body mass, BMI, body fat percentage and muscle mass). Twenty-seven of the interested 50 potential participants (54%) enrolled in the study, with 17 of the 27 participants completing the trial (withdrawal rate of 37%); with the primary withdrawal reasons being unrelated injuries or illness or family related issues. Of the 17 participants who completed the trial, exercise adherence was very high (HIIT 94%; MICT 88%). While only three individuals (one in the MICT and two in the HIIT group) reported adverse events, a total of 28 adverse events were reported, with 24 of these

  4. Is high-intensity interval cycling feasible and more beneficial than continuous cycling for knee osteoarthritic patients? Results of a randomised control feasibility trial

    Directory of Open Access Journals (Sweden)

    Justin W. Keogh

    2018-05-01

    Full Text Available Background Knee osteoarthritis (OA patients often suffer joint pain and stiffness, which contributes to negative changes in body composition, strength, physical performance (function, physical activity and health-related quality of life. To reduce these symptoms and side effects of knee OA, moderate-intensity continuous training (MICT cycling is often recommended. While resistance training is considered the optimal form of training to improve sarcopenic outcomes, it imposes higher joint loads and requires supervision, either initially or continuously by trained exercise professionals. Therefore, this pilot study sought to gain some insight into the feasibility and potential benefits of high-intensity interval training (HIIT cycling as an alternative exercise option to MICT cycling for individuals with knee OA. Methods Twenty-seven middle-aged and older adults with knee OA were randomly allocated to either MICT or HIIT, with both programs involving four unsupervised home-based cycling sessions (∼25 min per session each week for eight weeks. Feasibility was assessed by enrolment rate, withdrawal rate, exercise adherence and number of adverse effects. Efficacy was assessed by health-related quality of life (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC and Lequesne index, physical function (Timed Up and Go (TUG, Sit to Stand (STS and preferred gait speed and body composition (body mass, BMI, body fat percentage and muscle mass. Results Twenty-seven of the interested 50 potential participants (54% enrolled in the study, with 17 of the 27 participants completing the trial (withdrawal rate of 37%; with the primary withdrawal reasons being unrelated injuries or illness or family related issues. Of the 17 participants who completed the trial, exercise adherence was very high (HIIT 94%; MICT 88%. While only three individuals (one in the MICT and two in the HIIT group reported adverse events, a total of 28 adverse events were

  5. Supervision Duty of School Principals

    Directory of Open Access Journals (Sweden)

    Kürşat YILMAZ

    2009-04-01

    Full Text Available Supervision by school administrators is becoming more and more important. The change in the roles ofschool administrators has a great effect on that increase. At present, school administrators are consideredmore than as technical directors, but as instructional leaders. This increased the importance of schooladministrators’ expected supervision acts. In this respect, the aim of this study is to make a conceptualanalysis about school administrators’ supervision duties. For this reason, a literature review related withsupervision and contemporary supervision approaches was done, and the official documents concerningsupervision were examined. As a result, it can be said that school administrators’ supervision duties havebecome very important. And these duties must certainly be carried out by school administrators.

  6. Structural and Electrochemical Investigation during the First Charging Cycles of Silicon Microwire Array Anodes for High Capacity Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Helmut Föll

    2013-02-01

    Full Text Available Silicon microwire arrays embedded in Cu present exceptional performance as anode material in Li ion batteries. The processes occurring during the first charging cycles of batteries with this anode are essential for good performance. This paper sheds light on the electrochemical and structural properties of the anodes during the first charging cycles. Scanning Electron Microscopy, X-ray diffractommetry, and fast Fourier transformation impedance spectroscopy are used for the characterization. It was found that crystalline phases with high Li content are obtained after the first lithiation cycle, while for the second lithiation just crystalline phases with less Li are observable, indicating that the lithiated wires become amorphous upon cycling. The formation of a solid electrolyte interface of around 250 nm during the first lithiation cycle is evidenced, and is considered a necessary component for the good cycling performance of the wires. Analog to voltammetric techniques, impedance spectroscopy is confirmed as a powerful tool to identify the formation of the different Si-Li phases.

  7. Synthetic fuel production via carbon neutral cycles with high temperature nuclear reactors as a power source

    Energy Technology Data Exchange (ETDEWEB)

    Konarek, E.; Coulas, B.; Sarvinis, J. [Hatch Ltd., Mississauga, Ontario (Canada)

    2016-06-15

    This paper analyzes a number of carbon neutral cycles, which could be used to produce synthetic hydrocarbon fuels. Synthetic hydrocarbons are produced via the synthesis of Carbon Monoxide and Hydrogen. The . cycles considered will either utilize Gasification processes, or carbon capture as a source of feed material. In addition the cycles will be coupled to a small modular Nuclear Reactor (SMR) as a power and heat source. The goal of this analysis is to reduce or eliminate the need to transport diesel and other fossil fuels to remote regions and to provide a carbon neutral, locally produced hydrocarbon fuel for remote communities. The technical advantages as well as the economic case are discussed for each of the cycles presented. (author)

  8. Synthetic fuel production via carbon neutral cycles with high temperature nuclear reactors as a power source

    International Nuclear Information System (INIS)

    Konarek, E.; Coulas, B.; Sarvinis, J.

    2016-01-01

    This paper analyzes a number of carbon neutral cycles, which could be used to produce synthetic hydrocarbon fuels. Synthetic hydrocarbons are produced via the synthesis of Carbon Monoxide and Hydrogen. The . cycles considered will either utilize Gasification processes, or carbon capture as a source of feed material. In addition the cycles will be coupled to a small modular Nuclear Reactor (SMR) as a power and heat source. The goal of this analysis is to reduce or eliminate the need to transport diesel and other fossil fuels to remote regions and to provide a carbon neutral, locally produced hydrocarbon fuel for remote communities. The technical advantages as well as the economic case are discussed for each of the cycles presented. (author)

  9. Record productions establish RF-driven sources as the standard for generating high-duty-factor, high-current H- beams for accelerators (Winner of the ICIS 2017 Brightness Award)

    Science.gov (United States)

    Stockli, Martin P.; Welton, Robert F.; Han, Baoxi

    2018-05-01

    The Spallation Neutron Source operates reliably at 1.2 MW and will gradually ramp to 1.4 MW. This paper briefly recalls some of the struggles when the unprecedented project was started and ramped to 1 MW over a 3½ year period. This was challenging, especially for the H- ion source and the low-energy beam transport system, which make up the H- injector. It took several more years to push the H- injector to the 1.4 MW requirements, and even longer to reach close to 100% injector availability. An additional breakthrough was the carefully staged, successful extension of the H- source service cycle so that disruptive source changes became rare events. More than 7 A.h of extracted H- ions have been demonstrated with a single source without maintenance, more than twice the single-source quantity of ions produced by any other high-current H- accelerator facility. Achieving the 1.4 MW requirements with close to 100% availability and record-breaking source service cycles were the basis for the 2017 Brightness Award.

  10. Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power

    International Nuclear Information System (INIS)

    Brown, L.C.; Funk, J.F.; Showalter, S.K.

    1999-01-01

    OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study

  11. High-capacity FeTiO3/C negative electrode for sodium-ion batteries with ultralong cycle life

    Science.gov (United States)

    Ding, Changsheng; Nohira, Toshiyuki; Hagiwara, Rika

    2018-06-01

    The development of electrode materials which improve both the energy density and cycle life is one of the most challenging issues facing the practical application of sodium-ion batteries today. In this work, FeTiO3/C nanoparticles are synthesized as negative electrode materials for sodium-ion batteries. The electrochemical performance and charge-discharge mechanism of the FeTiO3/C negative electrode are investigated in an ionic liquid electrolyte at 90 °C. The FeTiO3/C negative electrode delivers a high reversible capacity of 403 mAh g-1 at a current rate of 10 mA g-1, and exhibits high rate capability and excellent cycling stability for up to 2000 cycles. The results indicate that FeTiO3/C is a promising negative electrode material for sodium-ion batteries.

  12. Heavy Duty Roots Expander Heat Energy Recovery (HD-REHER)

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami [Eaton Corporation, Menomonee Falls, WI (United States)

    2015-10-01

    Eaton Corporation proposed a comprehensive project to develop and demonstrate advanced component technology that will reduce the cost of implementing Organic Rankine Cycle (ORC) Waste Heat Recovery (WHR) systems to Heavy-Duty Diesel engines, making adaptation of this fuel efficiency improving technology more commercially attractive to end-users in the next 5 to 10 year time period. Accelerated adaptation and implementation of new fuel efficiency technology into service is critical for reduction of fuel used in the commercial vehicle segment.

  13. Development of a procedure for estimating the high cycle fatigue strength of some high temperature structural alloys

    International Nuclear Information System (INIS)

    Soo, P.; Chow, J.G.Y.

    1979-01-01

    The generation of strain controlled fatigue data, for the standard strain rate of 4 x 10 -3 sec -1 , presents a problem when the cycles to failure exceed 10 5 because of the prohibitively long test times involved. In an attempt to circumvent this difficulty an evaluation has been made of a test procedure involving a fast cycling rate (40 Hz) and load controlled conditions. The validity of this procedure for extending current fatigue curves from 10 5 to 10 8 cycles and beyond, hinges upon the selection of an appropriate effective strain value, since the strain usually changes rapidly during the early stage of fatigue. Results from annealed 2 1/4 Cr-1 Mo, type 304 stainless steel, Incoloy 800H and Hastelloy X, tested over a wide range of temperatures, show that the strain measured N/sub f/2 is a reasonable estimate since it gives an excellent correlation between the strain and load controlled tests in the 10 5 cycle range where the data overlap. It seems clear that the differences in cycling rate and early stress-strain history for the two tests do not significantly affect the correlation. It may, therefore, be concluded that such load control test procedures may be used as a valid fast way for extending currently available fatigue curves from 10 5 to 10 8 cycles, and beyond

  14. Avoiding thermal striping damage: Experimentally-based design procedures for high-cycle thermal fatigue

    International Nuclear Information System (INIS)

    Betts, C.; Judd, A.M.; Lewis, M.W.J.

    1994-01-01

    In the coolant circuits of a liquid metal cooled reactor (LMR), where there is turbulent mixing of coolant streams at different temperatures, there are temperature fluctuations in the fluid. If an item of the reactor structure is immersed in this fluid it will, because of the good heat transfer from the flowing liquid metal, experience surface temperature fluctuations which will induce dynamic surface strains. It is necessary to design the reactor so that these temperature fluctuations do not, over the life of the plant, cause damage. The purpose of this paper is to describe design procedures to prevent damage of this type. Two such procedures are given, one to prevent the initiation of defects in a nominally defect-free structure or to allow initiation only at the end of the component life, and the other to prevent significant growth of undetectable pre-existing defects of the order of 0.2 to 0.4 mm in depth. Experimental validation of these procedures is described, and the way they can be applied in practice is indicated. To set the scene the paper starts with a brief summary of cases in which damage of this type, or the need to avoid such damage, have had important effects on reactor operation. Structural damage caused by high-cycle thermal fatigue has had a significant adverse influence on the operation of LMRs on several occasions. It is necessary to eliminate the risk of such damage at the design stage. In the absence of detailed knowledge of the temperature history to which it will be subject, an LMR structure can be designed so that, if it is initially free of defects more than 0.1 mm deep, no such defects will be initiated by high-cycle fatigue. This can be done by ensuring that the maximum source temperature difference in the liquid metal is less than a limiting value, which depends on temperature. The limit is very low, however, and likely to be restrictive. This method, by virtue of its safety margin, takes into account pre-existing surface crack

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

    Energy Technology Data Exchange (ETDEWEB)

    Biganzoli, Laura, E-mail: laura.biganzoli@mail.polimi.it [Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. da Vinci 32, 20133 Milano (Italy); Racanella, Gaia [Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. da Vinci 32, 20133 Milano (Italy); Marras, Roberto [Unicalce S.p.A., R and D Department, Via Tonio da Belledo 30, 23900 Lecco (Italy); Rigamonti, Lucia [Politecnico di Milano, Department of Civil and Environmental Engineering, Piazza L. da Vinci 32, 20133 Milano (Italy)

    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

  16. A novel nuclear combined power and cooling system integrating high temperature gas-cooled reactor with ammonia–water cycle

    International Nuclear Information System (INIS)

    Luo, Chending; Zhao, Fuqiang; Zhang, Na

    2014-01-01

    Highlights: • We propose a novel nuclear ammonia–water power and cooling cogeneration system. • The high temperature reactor is inherently safe, with exhaust heat fully recovered. • The thermal performances are improved compared with nuclear combined cycle. • The base case attains an energy efficiency of 69.9% and exergy efficiency of 72.5%. • Energy conservation and emission reduction are achieved in this cogeneration way. - Abstract: A nuclear ammonia–water power and refrigeration cogeneration system (NAPR) has been proposed and analyzed in this paper. It consists of a closed high temperature gas-cooled reactor (HTGR) topping Brayton cycle and a modified ammonia water power/refrigeration combined bottoming cycle (APR). The HTGR is an inherently safe reactor, and thus could be stable, flexible and suitable for various energy supply situation, and its exhaust heat is fully recovered by the mixture of ammonia and water in the bottoming cycle. To reduce exergy losses and enhance outputs, the ammonia concentrations of the bottoming cycle working fluid are optimized in both power and refrigeration processes. With the HTGR of 200 MW thermal capacity and 900 °C/70 bar reactor-core-outlet helium, the system achieves 88.8 MW net electrical output and 9.27 MW refrigeration capacity, and also attains an energy efficiency of 69.9% and exergy efficiency of 72.5%, which are higher by 5.3%-points and 2.6%-points as compared with the nuclear combined cycle (NCC, like a conventional gas/steam power-only combined cycle while the topping cycle is a closed HTGR Brayton cycle) with the same nuclear energy input. Compared with conventional separate power and refrigeration generation systems, the fossil fuel saving (based on CH 4 ) and CO 2 emission reduction of base-case NAPR could reach ∼9.66 × 10 4 t/y and ∼26.6 × 10 4 t/y, respectively. The system integration accomplishes the safe and high-efficiency utilization of nuclear energy by power and refrigeration

  17. [Biogeochemical cycles in natural forest and conifer plantations in the high mountains of Colombia].

    Science.gov (United States)

    León, Juan Diego; González, María Isabel; Gallardo, Juan Fernando

    2011-12-01

    Plant litter production and decomposition are two important processes in forest ecosystems, since they provide the main organic matter input to soil and regulate nutrient cycling. With the aim to study these processes, litterfall, standing litter and nutrient return were studied for three years in an oak forest (Quercus humboldtii), pine (Pinus patula) and cypress (Cupressus lusitanica) plantations, located in highlands of the Central Cordillera of Colombia. Evaluation methods included: fine litter collection at fortnightly intervals using litter traps; the litter layer samples at the end of each sampling year and chemical analyses of both litterfall and standing litter. Fine litter fall observed was similar in oak forest (7.5 Mg ha/y) and in pine (7.8 Mg ha/y), but very low in cypress (3.5 Mg ha/y). Litter standing was 1.76, 1.73 and 1.3 Mg ha/y in oak, pine and cypress, respectively. The mean residence time of the standing litter was of 3.3 years for cypress, 2.1 years for pine and 1.8 years for oak forests. In contrast, the total amount of retained elements (N, P, S, Ca, Mg, K, Cu, Fe, Mn and Zn) in the standing litter was higher in pine (115 kg/ha), followed by oak (78 kg/ha) and cypress (24 kg/ha). Oak forests showed the lowest mean residence time of nutrients and the highest nutrients return to the soil as a consequence of a faster decomposition. Thus, a higher nutrient supply to soils from oaks than from tree plantations, seems to be an ecological advantage for recovering and maintaining the main ecosystem functioning features, which needs to be taken into account in restoration programs in this highly degraded Andean mountains.

  18. Storage and disposal of high-level radioactive waste from advanced FBR fuel cycle

    International Nuclear Information System (INIS)

    Nishihara, Kenji; Oigawa, Hiroyuki; Nakayama, Shinichi; Ono, Kiyoshi; Shiotani, Hiroki

    2011-01-01

    Waste management of fast breeder reactor (FBR) fuel cycle with and without partitioning and transmutation (P and T) technology was investigated by focusing on thermal constraints due to heat deposition from waste in storage and disposal facilities including economics aspects of those facilities. Partitioning of minor actinides (MAs) and heat-generating fission products in high-level waste can enlarge the containment ratio of waste elements in the glass waste forms and shorten predisposal storage period. Though MAs can be transmuted in FBRs or dedicated transmuters, heat-generating fission products are difficult to be transmuted; they are partitioned and stored for a long time before disposal. The disposal concepts for heat-generating fission products and remainders such as rare-earth elements depend on storage period that ranges from several years to several hundreds of years. Short-term storage results in small size of storage facilities and large size of repositories, and vice versa for long-term storage. This trade-off relation was analyzed by estimating repository size as a function of storage period. The result shows that transmutation of MAs is essentially effective to reduce repository size regardless to storage period, and a combination of P and T can provide a smaller repository than the conventional one by two orders of magnitude. The cost analysis for waste management was also made based on rough assumptions on storage, transportation and repository excluding cost for introducing P and T that are still under evaluation. Cost of waste management for FBR without P and T is 0.25 Yen/kWh that is slightly smaller than that for LWR without P and T, 0.30 Yen/kWh. The introduction of MA transmutation to the FBR results in cost of 0.20 Yen/kWh, and full introduction of P and T provides the smallest cost of 0.08 Yen/kWh. (author)

  19. Label-free cell-cycle analysis by high-throughput quantitative phase time-stretch imaging flow cytometry

    Science.gov (United States)

    Mok, Aaron T. Y.; Lee, Kelvin C. M.; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2018-02-01

    Biophysical properties of cells could complement and correlate biochemical markers to characterize a multitude of cellular states. Changes in cell size, dry mass and subcellular morphology, for instance, are relevant to cell-cycle progression which is prevalently evaluated by DNA-targeted fluorescence measurements. Quantitative-phase microscopy (QPM) is among the effective biophysical phenotyping tools that can quantify cell sizes and sub-cellular dry mass density distribution of single cells at high spatial resolution. However, limited camera frame rate and thus imaging throughput makes QPM incompatible with high-throughput flow cytometry - a gold standard in multiparametric cell-based assay. Here we present a high-throughput approach for label-free analysis of cell cycle based on quantitative-phase time-stretch imaging flow cytometry at a throughput of > 10,000 cells/s. Our time-stretch QPM system enables sub-cellular resolution even at high speed, allowing us to extract a multitude (at least 24) of single-cell biophysical phenotypes (from both amplitude and phase images). Those phenotypes can be combined to track cell-