Sample records for accelerated life-time testing

  1. Accelerated life-time testing and resistance degradation of thin-film decoupling capacitors

    SciTech Connect

    Al-Shareef, H.; Dimos, D.

    1996-09-01

    Resistance degradation in PZT thin-film capacitors has been studied as a function of applied voltage, temperature, and film composition. It is found that the mean-time-to-failure (life-time or t{sub f}) of the capacitors shows a power law dependence on applied voltage of he form t{sub f} {proportional_to} V{sup {minus}n} (n {approximately} 4--5). The capacitor life-time also exhibits a temperature dependence of the form t{sub f} {proportional_to} exp(E{sub a}/kT), with an activation energy of {approximately} 0.8 eV. The steady-state leakage current in these samples appears to be bulk controlled. The voltage, temperature, and polarity dependence of the leakage current collectively suggest a leakage current mechanism most similar to a Frenkel-Poole process. The life-time and leakage current of the Nb-doped PZT films are superior to the undoped PZT films. This result can be explained based on the point-defect chemistry of the PZT system. Finally, the results indicate that the Nb-doped PZT films meet the essential requirements for decoupling capacitor applications.

  2. Acceleration factors of combined reliability tests of lead-free SnAgCu BGA interconnections

    Microsoft Academic Search

    Przemyslaw Matkowski

    2011-01-01

    The essence of accelerated reliability test is to accelerate degradation process of tested object and the assessment of its reliability in test and field conditions. Acceleration factor is a unitless parameter that relates a life time of objects at an accelerated stress level to the life time at the use stress level. Acceleration factor of a single loading reliability tests

  3. A fast test technique for life time estimation of ultrasonically welded Cu-Cu interconnects

    Microsoft Academic Search

    B. Czerny; G. Khatibi; B. Weiss; T. Licht

    2010-01-01

    In this research the quality of the interconnects of the ultrasonically welded Cu terminals to the Cu substrate in the IGBT-module has been investigated. An ultrasonic resonance fatigue system in combination with a laser Doppler vibrometer and a special specimen design was used for shear fatigue testing of these large ultrasonic Cu–Cu welds (about 0.5 cm2). Fatigue life curves up

  4. Accelerated testing of space batteries

    NASA Technical Reports Server (NTRS)

    Mccallum, J.; Thomas, R. E.; Waite, J. H.

    1973-01-01

    An accelerated life test program for space batteries is presented that fully satisfies empirical, statistical, and physical criteria for validity. The program includes thermal and other nonmechanical stress analyses as well as mechanical stress, strain, and rate of strain measurements.

  5. Accelerated Stress-Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Test procedures for accelerated stress-corrosion testing of high-strength aluminum alloys faster and provide more quantitative information than traditional pass/fail tests. Method uses data from tests on specimen sets exposed to corrosive environment at several levels of applied static tensile stress for selected exposure times then subsequently tensile tested to failure. Method potentially applicable to other degrading phenomena (such as fatigue, corrosion fatigue, fretting, wear, and creep) that promote development and growth of cracklike flaws within material.

  6. Regional Accelerated Aging Test

    Microsoft Academic Search

    Ryoko Yamasaki; James T. McEvoy

    2003-01-01

    Customers' expectations for a consistent long-term high-level product performance have been increasing year after year, and the automotive industry is leading the trend. As an automotive seating component, polyurethane foam has a direct impact to the perceived value of an occupant, thus providing high durability foam became essential to customer satisfaction. Many tests were developed to evaluate the foam durability

  7. Accelerated Testing Validation

    SciTech Connect

    Mukundan, Rangachary; James, Greg; Davey, John; Langlois, David; Torraco, Dennis; Yoon, Wonseok; Weber, Adam Z; Borup, Rodney L.

    2011-07-01

    The DOE Fuel Cell technical team recommended ASTs were performed on 2 different MEAs (designated P5 and HD6) from Ballard Power Systems. These MEAs were also incorporated into stacks and operated in fuel cell bus modules that were either operated in the field (three P5 buses) in Hamburg, or on an Orange county transit authority drive cycle in the laboratory (HD6 bus module). Qualitative agreement was found in the degradation mechanisms and rates observed in the AST and in the field. The HD6 based MEAs exhibited lower voltage degradation rates (due to catalyst corrosion) and slower membrane degradation rates in the field as reflected by their superior performance in the high potential hold and open-circuit potential AST tests. The quantitative correlation of the degradation rates will have to take into account the various stressors in the field including temperature, relative humidity, start/stops and voltage cycles.

  8. Conditions of environmental accelerated testing

    Microsoft Academic Search

    L. M. Klyatis

    1998-01-01

    Strategical and tactical bases are developed for conditions for environmental accelerated testing of a product using physical simulation of life processes. These conditions permit rapid attainment of accurate information for reliability evaluation and prediction, technological development, cost effectiveness and competitive marketing of the product, etc

  9. Accelerated leach test development program

    SciTech Connect

    Fuhrmann, M.; Pietrzak, R.F.; Heiser, J.; Franz, E.M.; Colombo, P.

    1990-11-01

    In FY 1989, a draft accelerated leach test for solidified waste was written. Combined test conditions that accelerate leaching were validated through experimental and modeling efforts. A computer program was developed that calculates test results and models leaching mechanisms. This program allows the user to determine if diffusion controls leaching and, if this is the case, to make projections of releases. Leaching mechanisms other than diffusion (diffusion plus source term partitioning and solubility limited leaching) are included in the program is indicators of other processes that may control leaching. Leach test data are presented and modeling results are discussed for laboratory scale waste forms composed of portland cement containing sodium sulfate salt, portland cement containing incinerator ash, and vinyl ester-styrene containing sodium sulfate. 16 refs., 38 figs., 5 tabs.

  10. Accelerated testing of space mechanisms

    NASA Technical Reports Server (NTRS)

    Murray, S. Frank; Heshmat, Hooshang

    1995-01-01

    This report contains a review of various existing life prediction techniques used for a wide range of space mechanisms. Life prediction techniques utilized in other non-space fields such as turbine engine design are also reviewed for applicability to many space mechanism issues. The development of new concepts on how various tribological processes are involved in the life of the complex mechanisms used for space applications are examined. A 'roadmap' for the complete implementation of a tribological prediction approach for complex mechanical systems including standard procedures for test planning, analytical models for life prediction and experimental verification of the life prediction and accelerated testing techniques are discussed. A plan is presented to demonstrate a method for predicting the life and/or performance of a selected space mechanism mechanical component.

  11. Bayesian Optimum Planning for Accelerated Life Tests

    Microsoft Academic Search

    Yao Zhang; William Q. Meeker

    This paper describes a Bayesian method for optimum accelerated life test planning with one accelerating variable, when the acceleration model is linear in the parame- ters, based on censored data from a log-location-scale distribution. We use a Bayesian criterion based on estimation precision of a distribution quantile at a specified use condition and use this criterion to find optimum test

  12. The Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1992-09-01

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies.

  13. The Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1992-01-01

    The Brookhaven National Laboratory Accelerator Test Facility comprises a 50 MeV traveling wave electron linear accelerator utilizing a high gradient, photo-excited, raidofrequency electron gun as an injector and an experimental area for study of new acceleration methods or advanced radiation sources using free electron lasers. Early operation of the linear accelerator system including calculated and measured beam parameters are presented together with the experimental program for accelerator physics and free electron laser studies.

  14. Design on highway accelerated loading testing facility

    Microsoft Academic Search

    Zhiguang Guan; Mingxing Lin; Xuguang Wang; Jiwei Zhang

    2009-01-01

    Accelerated loading testing facility gains importance for proofing evaluations of structure designs as well as the final evaluation of new pavement materials and functions. So a highway accelerated loading testing facility is developed, which has self-owned intellectual property. The facility is made up of machine frame, a mobile car and a frame for dragging cable. The facility can test and

  15. Research of accelerated degradation test on server

    Microsoft Academic Search

    Xiaojie Zhang; Tongmin Jiang; Zheng Li

    2010-01-01

    Reliability is considered the core issues in face of server product at present; accelerated degradation testing is the significant method to assess the reliability & life of server. In this paper, after the stress analysis of operation & storage conditions for A950r-F server, accelerated degradation model based on uniform design are proposed, the testing design guideline are given. A series

  16. Accelerated Solar-UV Test Chamber

    NASA Technical Reports Server (NTRS)

    Gupta, A.; Laue, E. G.

    1984-01-01

    Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

  17. Accelerated stress testing of terrestrial solar cells

    NASA Technical Reports Server (NTRS)

    Lathrop, J. W.; Hawkins, D. C.; Prince, J. L.; Walker, H. A.

    1982-01-01

    The development of an accelerated test schedule for terrestrial solar cells is described. This schedule, based on anticipated failure modes deduced from a consideration of IC failure mechanisms, involves bias-temperature testing, humidity testing (including both 85-85 and pressure cooker stress), and thermal-cycle thermal-shock testing. Results are described for 12 different unencapsulated cell types. Both gradual electrical degradation and sudden catastrophic mechanical change were observed. These effects can be used to discriminate between cell types and technologies relative to their reliability attributes. Consideration is given to identifying laboratory failure modes which might lead to severe degradation in the field through second quadrant operation. Test results indicate that the ability of most cell types to withstand accelerated stress testing depends more on the manufacturer's design, processing, and worksmanship than on the particular metallization system. Preliminary tests comparing accelerated test results on encapsulated and unencapsulated cells are described.

  18. Accelerated Testing Of Photothermal Degradation Of Polymers

    NASA Technical Reports Server (NTRS)

    Kim, Soon Sam; Liang, Ranty Hing; Tsay, Fun-Dow

    1989-01-01

    Electron-spin-resonance (ESR) spectroscopy and Arrhenius plots used to determine maximum safe temperature for accelerated testing of photothermal degradation of polymers. Aging accelerated by increasing illumination, temperature, or both. Results of aging tests at temperatures higher than those encountered in normal use valid as long as mechanism of degradation same throughout range of temperatures. Transition between different mechanisms at some temperature identified via transition between activation energies, manifesting itself as change in slope of Arrhenius plot at that temperature.

  19. Test generation for radiotherapy accelerators

    Microsoft Academic Search

    Kenneth J. Turner

    2005-01-01

    System specification with L OTOS (Language Of Temporal Ordering Specification) is briefly introduced. To make test generatio n practicable, speci- fications are annotated with event constraints using PCL (Pa rameter Constraint Language) as a means of stating test purposes. Automated test generation can then use the principle of input-output conformance to check whether an implementa- tion agrees with its specification.

  20. Accelerated stress testing of terrestrial solar cells

    NASA Technical Reports Server (NTRS)

    Prince, J. L.; Lathrop, J. W.

    1979-01-01

    A program to investigate the reliability characteristics of unencapsulated low-cost terrestrial solar cells using accelerated stress testing is described. Reliability (or parametric degradation) factors appropriate to the cell technologies and use conditions were studied and a series of accelerated stress tests was synthesized. An electrical measurement procedure and a data analysis and management system was derived, and stress test fixturing and material flow procedures were set up after consideration was given to the number of cells to be stress tested and measured and the nature of the information to be obtained from the process. Selected results and conclusions are presented.

  1. Testing general relativity on accelerators

    E-print Network

    Tigran Kalaydzhyan

    2015-06-11

    Within the general theory of relativity, the curvature of space-time is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.

  2. Testing general relativity on accelerators

    E-print Network

    Kalaydzhyan, Tigran

    2015-01-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyse experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the Earth's gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of res...

  3. The accelerated testing of cements in brines

    SciTech Connect

    Krumhansl, J.L.

    1993-12-31

    Cementitious materials may be employed in settings where they face prolonged exposure to Mg-rich brines. This study evaluated the possibility of using high temperatures to accelerate brine-cement reaction rates. Class-H cement coupons were tested in Mg-K-Na-C1- SO{sub 4} brines to 100{degrees}C. MgC1{sub 2}-NaC1 solutions were also employed in a test sequence that extended to 200{degrees}C. It was found that accelerated testing could be used successfully to evaluate the compatability of cementitious materials with such brines.

  4. Accelerated testing for extended service AMTEC cells

    SciTech Connect

    Svedberg, R.C.; Schaupner, D.A. [Advanced Modular Power Systems, Inc., Ann Arbor, MI (United States); Appleby, A.J. [Texas A and M Univ., College Station, TX (United States). Center for electrochemical Systems and Hydrogen Research

    1997-12-31

    AMTEC cells are built with readily available materials, {beta}{double_prime}-alumina, stainless steel, Mo, Ta, TiCuNi and TiNi brazes, and TiN electrodes. The long term cell performance is dependent on the stability and inertness of these materials in the high temperature Na environment. The task of selecting materials and verifying that they will perform for long times (15 years for a deep space probe) is addressed. Accelerated testing methods and models to utilize the accelerated test data are being developed. A six and twelve month accelerated test plan to evaluate the BASE/Braze/Electrode/Current Collector (BASE Assembly) interfaces in Na vapor at 1,200, 1,100, and 1,000 K is described. An accelerated wick testing program is also discussed. The as-built BASE assembly braze interfaces have been evaluated. TiN electrodes, exposed for about 4,000 hours at 1,073 K are examined. This information will illustrate the direction being taken for evaluating lifetest results and developing models for life predictions.

  5. Developing MESA: An accelerated reliability test

    Microsoft Academic Search

    G. Baskoro; J. L. Rouvroye; W. Bacher; A. C. Brombacher

    2003-01-01

    This paper describes the on-going research on an accelerated reliability test strategy called MESA (Multiple Environment Stress Analysis) intended to find in a fast and efficient manner (potential) reliability problems during the design phase of high volume consumer products. This test has shown promising results on its capability to provoke failures, especially on failures formerly registered as NFF (no-fault-found). The

  6. Accelerated test plan for nickel cadmium spacecraft batteries

    NASA Technical Reports Server (NTRS)

    Hennigan, T. J.

    1973-01-01

    An accelerated test matrix is outlined that includes acceptance, baseline and post-cycling tests, chemical and physical analyses, and the data analysis procedures to be used in determining the feasibility of an accelerated test for sealed, nickel cadmium cells.

  7. Test Particles with Acceleration-Dependent Lagrangian

    E-print Network

    M. Toller

    2006-02-07

    We consider a classical test particle subject to electromagnetic and gravitational fields, described by a Lagrangian depending on the acceleration and on a fundamental length. We associate to the particle a moving local reference frame and we study its trajectory in the principal fibre bundle of all the Lorentz frames. We discuss in this framework the general form of the Lagrange equations and the connection between symmetries and conservation laws (Noether theorem). We apply these results to a model, already discussed by other authors, which implies an upper bound to the proper acceleration and to another new model in which a similar quantity, called ``pseudo-acceleration'', is bounded. With some simple choices of the fields, we illustrate some other interesting properties of the models and we show that unwanted features may appear, as unstable run-away solutions and unphysical values of the energy-momentum or of the velocity.

  8. Tests of compressed geometry acceleration tubes in the Oak Ridge 25URC tandem accelerator

    Microsoft Academic Search

    C. M. Jones; K. A. Erb; D. L. Haynes; J. T. Mitchell; N. F. Ziegler; J. E. Raatz; R. D. Rathmell

    1988-01-01

    In an effort to improve further the voltage performance of the Oak Ridge 25URC accelerator, the original acceleration tubes will be replaced with NEC compressed geometry acceleration tubes. In this paper, we report on tests in the 25URC accelerator of two prototype compressed geometry acceleration tube designs. One of the designs utilizes a novel aperture which provides enhanced electron and

  9. Tests of compressed geometry acceleration tubes in the Oak Ridge 25URC tandem accelerator

    Microsoft Academic Search

    C. M. Jones; K. A. Erb; D. L. Haynes; J. T. Mitchell; N. F. Ziegler; J. E. Raatz; R. D. Rathmell

    1987-01-01

    In an effort to further improve voltage performance of the Oak Ridge 25URC accelerator, the original acceleration tubes will be replaced with NEC compressed geometry acceleration tubes. In this paper, we report on tests in the 25URC accelerator of two prototype compressed geometry acceleration tube designs. One of the designs utilizes a novel aperture which provides enhanced electron and ion

  10. BNL ACCELERATOR TEST FACILITY CONTROL SYSTEM UPGRADE.

    SciTech Connect

    MALONE,R.; BEN-ZVI,I.; WANG,X.; YAKIMENKO,V.

    2001-06-18

    Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.

  11. Accelerated Aging Tests of Bubble Devices

    Microsoft Academic Search

    W. J. Tabor; R. Zappulla; A. W. Anderson

    1980-01-01

    Bubble devices are being manufactured by Western Electric Company, as well as a number of other companies, and have been used in the Bell System since 1978. Accelerated aging tests which include temperature-humidity-voltage bias exposure, temperature cycling, vibration and shock, and electromigration degradation of the Al-4.5% Cu conductors have been performed since the earliest bubble device was constructed. Many of

  12. Testing a combined vibration and acceleration environment.

    SciTech Connect

    Jepsen, Richard Alan; Romero, Edward F.

    2005-01-01

    Sandia National Laboratories has previously tested a capability to impose a 7.5 g-rms (30 g peak) radial vibration load up to 2 kHz on a 25 lb object with superimposed 50 g acceleration at its centrifuge facility. This was accomplished by attaching a 3,000 lb Unholtz-Dickie mechanical shaker at the end of the centrifuge arm to create a 'Vibrafuge'. However, the combination of non-radial vibration directions, and linear accelerations higher than 50g's are currently not possible because of the load capabilities of the shaker and the stresses on the internal shaker components due to the combined centrifuge acceleration. Therefore, a new technique using amplified piezo-electric actuators has been developed to surpass the limitations of the mechanical shaker system. They are lightweight, modular and would overcome several limitations presented by the current shaker. They are 'scalable', that is, adding more piezo-electric units in parallel or in series can support larger-weight test articles or displacement/frequency regimes. In addition, the units could be mounted on the centrifuge arm in various configurations to provide a variety of input directions. The design along with test results will be presented to demonstrate the capabilities and limitations of the new piezo-electric Vibrafuge.

  13. Test particle acceleration by rotating jet magnetospheres

    E-print Network

    F. M. Rieger; K. Mannheim

    2000-11-01

    Centrifugal acceleration of charged test particles at the base of a rotating jet magnetosphere is considered. Based on an analysis of forces we derive the equation for the radial accelerated motion and present an analytical solution. It is shown that for particles moving outwards along rotating magnetic field lines, the energy gain is in particular limited by the breakdown of the bead-on-the-wire approximation which occurs in the vicinity of the light cylinder $r_{L}$. The corresponding upper limit for the maximum Lorentz factor $\\gamma_{max}$ for electrons scales $\\propto B^{2/3} r_{L}^{2/3}$, with $B$ the magnetic field strength at $r_{L}$, and is at most of the order of a $10^2-10^3$ for the conditions regarded to be typical for BL Lac objects. Such values suggest that this mechanism may provide pre-accelerated seed particles which are required for efficient Fermi-type particle acceleration at larger scales in radio jets.

  14. Ultra-accelerated natural sunlight exposure testing

    DOEpatents

    Jorgensen, Gary J. (Pine, CO); Bingham, Carl (Lakewood, CO); Goggin, Rita (Englewood, CO); Lewandowski, Allan A. (Evergreen, CO); Netter, Judy C. (Westminster, CO)

    2000-06-13

    Process and apparatus for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: a) concentrating solar flux uniformly; b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  15. An Accelerated Method for Soldering Testing

    SciTech Connect

    Han, Qingyou [ORNL; Xu, Hanbing [University of Tennessee, Knoxville (UTK); Ried, Paul [Ried, Engineering; Olson, Paul [Balzers, Inc.

    2007-01-01

    An accelerated method for testing die soldering has been developed. High intensity ultrasonic vibrations have been applied to simulate the die casting conditions such as high pressure and high molten metal velocity on the pin. The soldering tendency of steels and coated pins has been examined. The results suggest that in the low carbon steel/Al system, the onset of soldering is 60 times faster with ultrasonic vibration than that without ultrasonic vibration. In the H13/A380 system, the onset of soldering reaction is accelerated to between 30-60 times. Coatings significantly reduce the soldering tendency. For purposes of this study, several commercial coatings from Balzers demonstrated the potential for increasing the service life of core pins between 15 and 180 times.

  16. The Brookhaven accelerator test facility injection system

    SciTech Connect

    Wang, X.J.; Kirk, H.G.; Pellegrini, C.; McDonald, K.T.; Russell, D.P.

    1989-01-01

    The Brookhaven Accelerator Test Facility (ATF) consists of a 50-MeV/c electron linac and a high-brightness RF-gun both operating at 2856 MHz. An extremely short (a few picoseconds) electron pulse with low transverse emittance is generated by the RF-gun. In order to preserve both longitudinal and transverse emittances, great care must be taken in transporting the electron beam from the RF-gun to the linac. We describe the injection line, present first- and second-order lattice studies of the injection line, and study nonlinear effects on the emittance. 11 refs., 4 figs., 4 tabs.

  17. Accelerated Strength Testing of Thermoplastic Composites

    NASA Technical Reports Server (NTRS)

    Reeder, J. R.; Allen, D. H.; Bradley, W. L.

    1998-01-01

    Constant ramp strength tests on unidirectional thermoplastic composite specimens oriented in the 90 deg. direction were conducted at constant temperatures ranging from 149 C to 232 C. Ramp rates spanning 5 orders of magnitude were tested so that failures occurred in the range from 0.5 sec. to 24 hrs. (0.5 to 100,000 MPa/sec). Below 204 C, time-temperature superposition held allowing strength at longer times to be estimated from strength tests at shorter times but higher temperatures. The data indicated that a 50% drop in strength might be expected for this material when the test time is increased by 9 orders of magnitude. The shift factors derived from compliance data applied well to the strength results. To explain the link between compliance and strength, a viscoelastic fracture model was investigated. The model, which used compliance as input, was found to fit the strength data only if the critical fracture energy was allowed to vary with temperature reduced stress rate. This variation in the critical parameter severely limits its use in developing a robust time-dependent strength model. The significance of this research is therefore seen as providing both the indication that a more versatile acceleration method for strength can be developed and the evidence that such a method is needed.

  18. Bayesian Methods for Accelerated Destructive Degradation Test Planning

    E-print Network

    Bayesian Methods for Accelerated Destructive Degradation Test Planning Ying Shi Dept. of Statistics University Ames, IA 50011 wqmeeker@iastate.edu Abstract Accelerated Destructive Degradation Tests (ADDTs destructive degradation tests (ADDTs) are sometimes used in manufac- turing industries to obtain reliability

  19. Accelerated Leach Test(s) Program. Annual report

    SciTech Connect

    Dougherty, D.R.; Fuhrmann, M.; Colombo, P.

    1985-09-01

    This report summarizes the work performed for the Accelerated Leach Test(s) Program at Brookhaven National Laboratory in Fiscal Year 1985 under the sponsorship of the US Department of Energy's Low-Level Waste Management Program (LLWMP). Programmatic activities were concentrated in three areas, as listed and described in the following paragraphs. (1) A literature survey of reported leaching mechanisms, available mathematical models and factors that affect leaching of LLW forms has been compiled. Mechanisms which have been identified include diffusion, dissolution, ion exchange, corrosion and surface effects. Available mathematical models are based on diffusion as the predominant mechanism. Although numerous factors that affect leaching have been identified, they have been conveniently categorized as factors related to the entire leaching system, to the leachant or to the waste form. A report has been published on the results of this literature survey. (2) A computerized data base of LLW leaching data and mathematical models is being developed. The data are being used for model evaluation by curve fitting and statistical analysis according to standard procedures of statistical quality control. (3) Long-term tests on portland cement, bitumen and vinyl ester-styrene (VES) polymer waste forms are underway which are designed to identify and evaluate factors that accelerate leaching without changing the mechanisms. Results on the effect of temperature on leachability indicate that the leach rates of cement and VES waste forms increase with increasing temperature, whereas, the leach rate of bitumen is little affected.

  20. DNA Bubble Life Time in Denaturation

    E-print Network

    Zh. S. Gevorkian; Chin-Kun Hu

    2010-10-11

    We have investigated the denaturation bubble life time for a homogeneous as well as for a heterogeneous DNA within a Poland-Scheraga model. It is shown that at criticality the bubble life time for a homogeneous DNA is finite provided that the loop entropic exponent c>2 and has a scaling dependence on DNA length for c<2. Heterogeneity in the thermodynamical limit makes the bubble life time infinite for any entropic exponent.

  1. Operation of the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Ben-Zvi, I.; Botke, I.; Chou, T.S.; Fernow, R.; Fischer, J.; Fisher, A.; Gallardo, J.; Ingold, G.; Malone, R.; Palmer, R.; Parsa, Z.; Pogorelsky, I.; Rogers, J.; Sheehan, J.; Srinivasan-Rao, T.; Tsang, T.; Ulc, S.; van Steenbergen, A.; Wang, X.J.; Woodle, M.; Yu, L.H.

    1992-10-01

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program.

  2. Operation of the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Ben-Zvi, I.; Botke, I.; Chou, T.S.; Fernow, R.; Fischer, J.; Fisher, A.; Gallardo, J.; Ingold, G.; Malone, R.; Palmer, R.; Parsa, Z.; Pogorelsky, I.; Rogers, J.; Sheehan, J.; Srinivasan-Rao, T.; Tsang, T.; Ulc, S.; van Steenbergen, A.; Wang, X.J.; Woodle, M.; Yu, L.H.

    1992-01-01

    Early operation of the 50 MeV high brightness electron linac of the Accelerator Test Facility is described along with experimental data. This facility is designed to study new linear acceleration techniques and new radiation sources based on linacs in combination with free electron lasers. The accelerator utilizes a photo-excited, metal cathode, radio frequency electron gun followed by two travelling wave accelerating sections and an Experimental Hall for the study program.

  3. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The 250 C, 200C and 125C accelerated tests are described. The wear-out distributions from the 250 and 200 C tests were used to estimate the activation energy between the two test temperatures. The duration of the 125 C test was not sufficient to bring the test devices into the wear-out region. It was estimated that, for the most complex of the three devices types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment is assessed. Guidlines for the development of accelerated life-test conditions are proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life-test characteristics of CMOS microcircuits is described.

  4. Ground test accelerator control system software

    Microsoft Academic Search

    L. Burczyk; R. Dalesio; R. Dingler; J. Hill; J. A. Howell; D. Kerstiens; R. King; A. Kozubal; C. Little; V. Martz; R. Rothrock; J. Sutton

    1988-01-01

    The GTA control system provides an environment in which the automation of a state-of-the-art accelerator can be developed. It makes use of commercially available computers, workstations, computer networks, industrial I\\/O equipment, and software. This system has built-in supervisory control (like most accelerator control systems), tools to support continuous control (like the process control industry), and sequential control for automatic startup

  5. Highly accelerated life testing for non-hermetic laser modules

    Microsoft Academic Search

    C. D. Theis; D. J. Siconolfi; R. B. Comizzoli; P. A. Kiely; P. Wu; U. K. Chakrabarti; J. W. Osenbach

    2000-01-01

    Reliability testing using accelerators such as temperature and humidity for electronic components has evolved from conventional temperature\\/humidity\\/bias (THB) testing (85°C\\/85% RH\\/bias) to the use of highly accelerated temperature and humidity stress testing (HAST). This advancement was in part made possible by the availability of stable commercial HAST systems that have eliminated problems with condensation and pressure-reduction rates. In this paper

  6. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

    2011-01-01

    Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

  7. Beam Physics of Integrable Optics Test Accelerator at Fermilab

    SciTech Connect

    Nagaitsev, S.; Valishev, A.; /Fermilab; Danilov, V.V.; /Oak Ridge; Shatilov, D.N.; /Novosibirsk, IYF

    2012-05-01

    Fermilab's Integrable Optics Test Accelerator (IOTA) is an electron storage ring designed for testing advanced accelerator physics concepts, including implementation of nonlinear integrable beam optics and experiments on optical stochastic cooling. The machine is currently under construction at the Advanced Superconducting Test Accelerator facility. In this report we present the goals and the current status of the project, and describe the details of machine design. In particular, we concentrate on numerical simulations setting the requirements on the design and supporting the choice of machine parameters.

  8. Computer modeling of test particle acceleration at oblique shocks

    Microsoft Academic Search

    Robert B. Decker

    1988-01-01

    We review the basic techniques and results of numerical codes used to model the acceleration of charged particles at oblique, fast-mode, collisionless shocks. The emphasis is upon models in which accelerated particles (ions) are treated as test particles, and particle dynamics is calculated by numerically integrating along exact phase-space orbits. We first review the case where ions are sufficiently energetic

  9. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This report covers the time period from May 1976 to December 1979 and encompasses the three phases of accelerated testing: Phase 1, the 250 C testing; Phase 2, the 200 C testing; and Phase 3, the 125 C testing. The duration of the test in Phase 1 and Phase 2 was sufficient to take the devices into the wear out region. The wear out distributions were used to estimate the activation energy between the 250 C and the 200 C test temperatures. The duration of the 125 C test, 20,000 hours, was not sufficient to bring the test devices into the wear out region; consequently the third data point at 125 C for determining the consistency of activation energy could not be obtained. It was estimated that, for the most complex of the three device types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment was assessed. Guidelines for the development of accelerated life test conditions were proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life test characteristics of CMOS microcircuits was explored in Phase 4 of this study and is attached as an appendix to this report.

  10. Tests of compressed geometry NEC acceleration tubes

    Microsoft Academic Search

    James E. Raatz; Robert D. Rathmell; Paul H. Stelson; Norval F. Ziegler

    1986-01-01

    Tests have been performed in the 3 MV Pelletron test machine at NEC on a compressed geometry tube which increases the insulating length of the tube by eliminating the heated electrode assemblies (~ 2.5 cm thick) at the end of each tube section. Some insert electrodes are changed to provide some trapping of secondary ions. The geometry tested provided an

  11. Tests of compressed geometry NEC acceleration tubes

    Microsoft Academic Search

    J. E. Raatz; R. D. Rathmell; P. H. Stelson; N. F. Ziegler

    1985-01-01

    Tests have been performed in the 3 MV Pelletron test machine at NEC on a compressed geometry tube which increases the insulating length of the tube by eliminating the heated electrode assemblies (approx. 2.5 cm thick) at the end of each tube section. Some insert electrodes are changed to provide some trapping of secondary ions. The geometry tested provided an

  12. Accelerated testing method of LED luminaries

    Microsoft Academic Search

    M. Cai; D. G. Yang; S. Koh; C. A. Yuan; W. B. Chen; B. Y. Wu; G. Q. Zhang

    2012-01-01

    With rapid development of lighting emitting diode (LED) market, more people are focusing on reliability testing method of LED luminaries system. However, it is difficult to use traditional reliability testing method for electronic products to assess LED luminaries with high reliability and long life. In this paper, reliability testing methods applied on LED, LED luminaries and other fields are reviewed

  13. Reliability Accelerated Testing of MEMS Acccelerometers

    Microsoft Academic Search

    M. Bazu; L. Galateanu; V. E. Ilian; J. Loicq; S. Habraken; J.-P. Colette

    2007-01-01

    An attempt to assess the reliability of a batch of MEMS accelerometers is presented. The testing plan is application oriented and contains combined tests: thermal and mechanical stresses (two variants: vibration and tilting) were used. The results demonstrated the good reliability of the tested device, the failure rate being smaller than 6.10-8 h-1.

  14. Evaluation of an Accelerated ELDRS Test Using Molecular Hydrogen

    NASA Technical Reports Server (NTRS)

    Pease, Ronald L.; Adell, Philippe C.; Rax, Bernard; McClure, Steven; Barnaby, Hugh J.; Kruckmeyer, Kirby; Triggs, B.

    2011-01-01

    An accelerated total ionizing dose (TID) hardness assurance test for enhanced low dose rate sensitive (ELDRS) bipolar linear circuits, using high dose rate tests on parts that have been exposed to molecular hydrogen, has been proposed and demonstrated on several ELDRS part types. In this study several radiation-hardened "ELDRS-free" part types have been tested using this same approach to see if the test is overly conservative.

  15. Preliminary description of the ground test accelerator cryogenic cooling system

    SciTech Connect

    Edeskuty, F.J.; Stewart, W.F.

    1988-01-01

    The Ground Test Accelerator (GTA) under construction at the Los Alamos National Laboratory is part of the Neutral Particle Beam Program supported by the Strategic Defense Initiative Office. The GTA is a full-sized test facility to evaluate the feasibility of using a negative ion accelerator to produce a neutral particle beam (NPB). The NPB would ultimately be used outside the earth's atmosphere as a target discriminator or as a directed energy weapon. The operation of the GTA at cryogenic temperature is advantageous for two reasons: first, the decrease of temperature caused a corresponding decrease in the rf heating of the copper in the various units of the accelerator, and second, at the lower temperature the decrease in the thermal expansion coefficient also provides greater thermal stability and consequently, better operating stability for the accelerator. This paper discusses the cryogenic cooling system needed to achieve these advantages. 5 figs., 3 tabs.

  16. Simulation of drop testing at extremely high accelerations

    Microsoft Academic Search

    S. Douglas; M. Al-Bassyiouni; A. Dasgupta

    2010-01-01

    Advances in drop tower technology have extended the range of obtainable accelerations in drop testing from 5,000 Gs to as much as 100,000 Gs. To achieve excitations in excess of the conventional 5,000 Gs, a mechanical accelerator, called the Dual Mass Shock Amplifier (DMSA), is mounted on the drop table. This device produces extremely high, short duration shock amplitudes, by

  17. The Accelerator Systems String Test cryogenics

    SciTech Connect

    Mulholland, G.T.

    1993-04-01

    The ASST magnet string cryogenic refrigeration requirements were planned around an original design and a much smaller, backup, He refrigeration system. The ASST schedule required that the backup, or Plan B, helium refrigerator provide and meet all the requirements of the milestone test. The Plan B design, layout, sub-system commissioning tests, and the performance schedule will be provided. The magnet string cryogenic system pump and purge, cooldown and warmup, central and multiple shield cooling, temperature control and subcooling, and recooler operating experience are reported. The ASST cryogenic system static performance and the dynamic provisions, response, and recovery to magnet quenches will be described.

  18. Accelerated life testing effects on CMOS microcircuit characteristics, phase 1

    NASA Technical Reports Server (NTRS)

    Maximow, B.

    1976-01-01

    An accelerated life test of sufficient duration to generate a minimum of 50% cumulative failures in lots of CMOS devices was conducted to provide a basis for determining the consistency of activation energy at 250 C. An investigation was made to determine whether any thresholds were exceeded during the high temperature testing, which could trigger failure mechanisms unique to that temperature. The usefulness of the 250 C temperature test as a predictor of long term reliability was evaluated.

  19. Earth Scanner Bearing Accelerated Life Test

    NASA Technical Reports Server (NTRS)

    Dietz, Brian J.; VanDyk, Steven G.; Predmore, Roamer E.

    2000-01-01

    The Moderate Resolution Imaging Spectrometer (MODIS) optical instrument for NASA Goddard will measure biological and physical processes on the Earth's surface and in the lower atmosphere. A key component of the instrument is an extremely accurate scan mirror motor/encoder assembly. Of prime concern in the performance and reliability of the scan motor/encoder is bearing selection and lubrication. This paper describes life testing of the bearings and lubrication selected for the program.

  20. SCAT--New test method for determining pitting corrosion rates. [Stray Current Accelerated Test

    SciTech Connect

    Singleton, H. (Mitchell Energy Corp., The Woodlands, TX (United States))

    1993-09-01

    A test procedure is described that has been used to determine if casing (tubulars) from various mills will corrode in a general or pitting-type pattern. The equipment required to run the test is relatively inexpensive and gives meaningful results in one to two weeks. The Stray Current Accelerated Test (SCAT) accelerates the corrosion rate for quick materials evaluation. Casings subjected to the SCAT test have been compared to actual failed casings and found to be almost identical.

  1. Quick setup of unit test for accelerator controls system

    SciTech Connect

    Fu, W.; D'Ottavio, T.; Gassner, D.; Nemesure, S.; Morris, J.

    2011-03-28

    Testing a single hardware unit of an accelerator control system often requires the setup of a program with graphical user interface. Developing a dedicated application for a specific hardware unit test could be time consuming and the application may become obsolete after the unit tests. This paper documents a methodology for quick design and setup of an interface focused on performing unit tests of accelerator equipment with minimum programming work. The method has three components. The first is a generic accelerator device object (ADO) manager which can be used to setup, store, and log testing controls parameters for any unit testing system. The second involves the design of a TAPE (Tool for Automated Procedure Execution) sequence file that specifies and implements all te testing and control logic. The sting third is the design of a PET (parameter editing tool) page that provides the unit tester with all the necessary control parameters required for testing. This approach has been used for testing the horizontal plane of the Stochastic Cooling Motion Control System at RHIC.

  2. The Brookhaven National Laboratory (BNL) Accelerator Test Facility

    SciTech Connect

    Batchelor, K.

    1990-01-01

    The design of the Brookhaven National Laboratory Accelerator Test Facility is presented including the design goals and computational results. The heart of the system is a radiofrequency electron gun utilizing a photo-excited metal cathode followed by a conventional electron linac. The Nd:YAG laser used to drive the cathode with 6 ps long pulses can be synchronized to a high peak power CO{sub 2} laser in order to study laser acceleration of electrons. Current operational status of the project will be presented along with early beam tests.

  3. Step-Stress Accelerated Degradation Testing for Solar Reflectors: Preprint

    SciTech Connect

    Jones, W.; Elmore, R.; Lee, J.; Kennedy, C.

    2011-09-01

    To meet the challenge to reduce the cost of electricity generated with concentrating solar power (CSP) new low-cost reflector materials are being developed including metalized polymer reflectors and must be tested and validated against appropriate failure mechanisms. We explore the application of testing methods and statistical inference techniques for quantifying estimates and improving lifetimes of concentrating solar power (CSP) reflectors associated with failure mechanisms initiated by exposure to the ultraviolet (UV) part of the solar spectrum. In general, a suite of durability and reliability tests are available for testing a variety of failure mechanisms where the results of a set are required to understand overall lifetime of a CSP reflector. We will focus on the use of the Ultra-Accelerated Weathering System (UAWS) as a testing device for assessing various degradation patterns attributable to accelerated UV exposure. Depending on number of samples, test conditions, degradation and failure patterns, test results may be used to derive insight into failure mechanisms, associated physical parameters, lifetimes and uncertainties. In the most complicated case warranting advanced planning and statistical inference, step-stress accelerated degradation (SSADT) methods may be applied.

  4. High-Voltage Terminal Test of Test Stand for 1-MV Electrostatic Accelerator

    E-print Network

    Park, Sae-Hoon

    2015-01-01

    The Korea Multipurpose Accelerator Complex (KOMAC) has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz RF power, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

  5. Brookhaven National Laboratory's Accelerator Test Facility: research highlights and plans

    NASA Astrophysics Data System (ADS)

    Pogorelsky, I. V.; Ben-Zvi, I.

    2014-08-01

    The Accelerator Test Facility (ATF) at Brookhaven National Laboratory has served as a user facility for accelerator science for over a quarter of a century. In fulfilling this mission, the ATF offers the unique combination of a high-brightness 80 MeV electron beam that is synchronized to a 1 TW picosecond CO2 laser. We unveil herein our plan to considerably expand the ATF's floor space with an upgrade of the electron beam's energy to 300 MeV and the CO2 laser's peak power to 100 TW. This upgrade will propel the ATF even further to the forefront of research on advanced accelerators and radiation sources, supporting the most innovative ideas in this field. We discuss emerging opportunities for scientific breakthroughs, including the following: plasma wakefield acceleration studies in research directions already active at the ATF; laser wakefield acceleration (LWFA), where the longer laser wavelengths are expected to engender a proportional increase in the beam's charge while our linac will assure, for the first time, the opportunity to undertake detailed studies of seeding and staging of the LWFA; proton acceleration to the 100-200 MeV level, which is essential for medical applications; and others.

  6. The BNL Accelerator Test Facility and experimental program

    SciTech Connect

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1992-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  7. The BNL Accelerator Test Facility and experimental program

    SciTech Connect

    Ben-Zvi, I. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics

    1992-09-01

    The Accelerator Test Facility (ATF) at BNL is a users` facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF`s experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  8. The BNL Accelerator Test Facility and experimental program

    SciTech Connect

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1991-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high power laser pulses synchronized to the electron beam, suitable for studies of new methods of high gradient acceleration and state of the art free electron lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 to 100 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps Nd:YAG laser and a 100 mJ, 10 ps CO{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various acceleration schemes, Free-Electron Laser experiments and a program on the development of high brightness electron beams. The AFT's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the High power laser will begin operation this year. 28 refs., 4 figs.

  9. Demonstration recommendations for accelerated testing of concrete decontamination methods

    Microsoft Academic Search

    K. S. Dickerson; M. R. Ally; C. H. Brown; M. I. Morris; M. J. Wilson-Nichols

    1995-01-01

    A large number of aging US Department of Energy (DOE) surplus facilities located throughout the US require deactivation, decontamination, and decommissioning. Although several technologies are available commercially for concrete decontamination, emerging technologies with potential to reduce secondary waste and minimize the impact and risk to workers and the environment are needed. In response to these needs, the Accelerated Testing of

  10. Research on the reliability of SLD through accelerated life testing

    Microsoft Academic Search

    Daihong Chao; Jing Ma; Xiaoyang Li

    2009-01-01

    As an important component, Super Luminescent Diode (SLD) is the most crucial factor that affects life and reliability of Interferotic Fiber Opitc Gyroscope(IFOG). Therefore, research on the reliability of SLD is the base of research on the reliability of IFOG. Research on the reliability of SLD was processed through accelerated life test (ALT). Based on related theoretic analysis, the sensitive

  11. Research of accelerated life test of cycle-life products

    Microsoft Academic Search

    Tianye Li; Xiaohong Wang

    2009-01-01

    Work was carried out in order to make the results of accelerated life test of the cycle-life products more accurate. Two kinds of products which both use cycle numbers as a main life indicator were mentioned to explain the essence of cycle-life of product. And by analyzing the latest research results of their failure mechanisms, possible improvements of cycle conditions

  12. Reliability estimation of aeronautic component by accelerated tests

    Microsoft Academic Search

    S. Charruau; F. Guerin; J. Hernández Dominguez; J. Berthon

    2006-01-01

    This article presents a reliability assessment of aeronautic electronic board using the accelerated test approach. The mission profile used is one defined in FIDES for electronic equipment in aircraft. The reliability function is defined taking into account the different phases of product life (Ground, Taxiing, Flying, Dormant). FIDES describes the environment (thermal and humidity, thermal cycling, mechanical, …) for each

  13. 46 CFR 160.072-5 - Accelerated weathering test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Distress Signals for Boats, Orange Flag § 160.072-5 Accelerated weathering test. (a) Condition the flag, folded to 1/16 th its size or as...least 15 days. (b) Unfold and suspend flag by the lines provided, secured...

  14. 46 CFR 160.072-5 - Accelerated weathering test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Distress Signals for Boats, Orange Flag § 160.072-5 Accelerated weathering test. (a) Condition the flag, folded to 1/16 th its size or as...least 15 days. (b) Unfold and suspend flag by the lines provided, secured...

  15. 46 CFR 160.072-5 - Accelerated weathering test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Distress Signals for Boats, Orange Flag § 160.072-5 Accelerated weathering test. (a) Condition the flag, folded to 1/16 th its size or as...least 15 days. (b) Unfold and suspend flag by the lines provided, secured...

  16. High current electron linacs (advanced test accelerator/experimental test accelerator)

    SciTech Connect

    Briggs, R.J.

    1984-04-30

    The high current induction accelerator development at the Lawrence Livermore National Laboratory is described. The ATA facility is designed for 10 kA peak currents, 50 nsec pulse lengths and 50 MeV energies. At this time, half of the design current has been accelerated through the entire machine to particle energies of about 45 MeV. Current problem areas and operational experience to date will be discussed. Several key technical areas required development for the ATA machine; this report will survey these developments. The control of transverse beam instabilities required an accelerating cavity design with very low Q. Electron sources capable of 10 kA operation at high rep rates were developed using a plasma sparkboard approach. The pulse power systems on ATA, using the same type of spark gap switches as ETA, have exhibited excellent operational reliability.

  17. Optimum simple step-stress accelerated life tests with censoring

    Microsoft Academic Search

    D. S. Bai; M. S. Kim; S. H. Lee

    1989-01-01

    The authors present the optimum simple time-step and failure-step stress accelerated life tests for the case where a prespecified censoring time is involved. An exponential life distribution with a mean that is a log-linear function of stress, and a cumulative exposure model are assumed. The authors obtain the optimum test plans to minimize the asymptotic variance of the maximum-likelihood estimator

  18. Accelerated Wear Tests on Common Floor-covering Materials.

    E-print Network

    Stewart, B. R.; Kunze, O. R.; Hobgood, Price.

    1958-01-01

    *'r** qd** ""~c- web*- !,* . flccelerated Wear Tests e" f loor-couering materials AGRICULTURAL EXPERIMENT STATION R. D. LEWIS, DIRECTOR, COLLEGE STATION. TEXAS SUMMARY I .. - " : 5: Accelerated wear tests made on six common floor covering... materials indicated there are variations in the changes of appearance and wear in these materials. Solid sheet vinyls and rubber tiles showed significantly less wear than asphalt tiles, vinyl- asbestos tiles, linoleums and cork. Asphalt tiles showed...

  19. Free-electron laser results from the Advanced Test Accelerator

    SciTech Connect

    Orzechowski, T.J.; Miller, J.L.; Weir, J.T.; Chong, Y.P.; Chambers, F.; Deis, G.A.; Paul, A.C.; Prosnitz, D.; Scharlemann, E.T.; Hallbach, K.

    1988-10-01

    PALADIN is a 10.6-..mu..m FEL amplifier experiment operating at the Lawrence Livermore National Laboratory's Advanced Test Accelerator, an induction linear accelerator designed to produce a 45-MeV, 10-kA electron beam. With a 15-m long wiggler, PALADIN demonstrated 27 dB of exponential gain from a 14-kW input signal. With a 5-MW input signal, the amplifier saturated after 10 dB of gain. The exponentially growing signal in the unsaturated amplifier was clearly seen to be gain guided by the electron beam. 7 refs., 8 figs.

  20. An Accelerated Method for Testing Soldering Tendency of Core Pins

    SciTech Connect

    Han, Qingyou [ORNL; Xu, Hanbing [ORNL; Ried, Paul [Ried, Engineering; Olson, Paul [Balzers, Inc.

    2010-01-01

    An accelerated method for testing die soldering has been developed. High intensity ultrasonic vibrations has been used to simulate the die casting conditions such as high pressure and high impingement speed of molten metal on the pin. Soldering tendency of steels and coated pins has been examined. The results indicate that in the low carbon steel/Al system, the onset of soldering is 60 times faster with ultrasonic vibration than that without ultrasonic vibration. In the H13/A380 system, the onset of soldering reaction is accelerated to 30-60 times. Coating significantly reduces the soldering tendency of the core pins.

  1. An Integration Testing Facility for the CERN Accelerator Controls System

    E-print Network

    Stapley, N; Bau, J C; Deghaye, S; Dehavay, C; Sliwinski, W; Sobczak, M

    2009-01-01

    A major effort has been invested in the design, development, and deployment of the LHC Control System. This large control system is made up of a set of core components and dependencies, which although tested individually, are often not able to be tested together on a system capable of representing the complete control system environment, including hardware. Furthermore this control system is being adapted and applied to CERN's whole accelerator complex, and in particular for the forthcoming renovation of the PS accelerators. To ensure quality is maintained as the system evolves, and toimprove defect prevention, the Controls Group launched a project to provide a dedicated facility for continuous, automated, integration testing of its core components to incorporate into its production process. We describe the project, initial lessons from its application, status, and future directions.

  2. On the life time of contrail cirrus

    NASA Astrophysics Data System (ADS)

    Schumann, U.; Graf, K.

    2012-04-01

    Contrails represent reproducible prototypes of cirrus clouds which are easier to understand scientifically and offer better chances for experimental investigations than natural cirrus. In the past, investigation of contrails led to important general insight into the atmosphere system, such as the detection of ice supersaturation, homogeneous and heterogeneous ice particle formation, and subvisible cirrus. Even the Brewer-Dobson circulation was detected because contrails were observed to be short-lived at multitudes above the tropopause. Here we present results constraining the mean life time of contrail cirrus based on comparisons of results from a new contrail cirrus model, ECMWF forecast data and several years of Meteosat satellite observations for the North Atlantic and Europe. The mean life time of contrails is not yet well known. Persistent contrails form at aviation cruise altitudes mainly in the upper troposphere, when the temperature is below the Schmidt-Appleman (SAC) threshold temperature and when the ambient atmosphere is humid enough for long-lived contrails. The SAC threshold depends on aircraft and fuel properties, pressure and humidity. Contrails spread and persist in ice supersaturated air masses. Contrails are visible also for several minutes or even longer when the relative humidity is slightly below saturation, in particular at low temperatures. Contrails survive until the ambient air gets dried beyond ice saturation (e.g. by subsidence, mixing with dry air, radiative warming) or until the ice particles get large enough to sediment quickly and to fall down into drier air masses or, rarely, precipitate to ground. Contrails with large ice particles may end in fallstreaks (i.e. in a curtain of large and quickly falling ice particles). With time, contrails may loose their identity and become part of other thicker cirrus clouds. We model the formation and decay of contrails for a fleet of aircraft using a recently developed Lagrangian contrail cirrus prediction model CoCiP (Schumann, U.: A contrail cirrus prediction model, Geosci. Model Dev. Discuss., 4, 3185-3293, doi:10.5194/gmdd-4-3185-2011, 2011). The formation of contrails and their transition into contrail cirrus is modeled for given aircraft types, aircraft tracks and given meteorology (taken from ECMWF). We found that the computed contrail cover is highly sensitive to the processes which limit the life time of contrail cirrus. The life-time of contrail clusters should be similar to the lifetime of ice supersaturated regions (ISSR) which has been estimated at mid-latitudes to vary from minutes to possibly a few days with median values of order hours. Here, we estimate the life-time of ISSR regions by computing the age of trajectories which start at aircraft waypoints satisfying the SAC in ice supersaturated air and last until the ambient humidity drops below ice saturation. This aircraft-related ISSR-life-time is not the life-time of ISSR per se, but the life-time of ice supersaturation relevant for contrails. For this purpose we use the Lagrangian trajectory model part of CoCiP for a passive tracer with ECMWF data. Most of such trajectories end after less than one hour. The age frequency distribution follows an exponential function. Based on such a fit the mean and median ages of ISSR regions are 14.6 and 10.1 h. The life time depends on many parameters; it is large in particular in the upper and mid polar and upper tropical troposphere. When we apply CoCiP for contrails including ice formation form ambient ice supersaturation but without any particle number loss process, we compute ages which exceed the ISSR ages. The larger life time result from the reservoir of ice water built up in the contrails while staying in the ISSR. This ice water reservoir is a maximum just when the ISSR regime ends. It takes considerable time to mix drier ambient air into the contrail and to sublimate this ice. Hence, the total contrail age without ice loss processes could reach about 1.5 times the age of ISSR masses. With some loss processes included in the model, the c

  3. Preloading To Accelerate Slow-Crack-Growth Testing

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John P.; Choi, Sung R.; Pawlik, Ralph J.

    2004-01-01

    An accelerated-testing methodology has been developed for measuring the slow-crack-growth (SCG) behavior of brittle materials. Like the prior methodology, the accelerated-testing methodology involves dynamic fatigue ( constant stress-rate) testing, in which a load or a displacement is applied to a specimen at a constant rate. SCG parameters or life prediction parameters needed for designing components made of the same material as that of the specimen are calculated from the relationship between (1) the strength of the material as measured in the test and (2) the applied stress rate used in the test. Despite its simplicity and convenience, dynamic fatigue testing as practiced heretofore has one major drawback: it is extremely time-consuming, especially at low stress rates. The present accelerated methodology reduces the time needed to test a specimen at a given rate of applied load, stress, or displacement. Instead of starting the test from zero applied load or displacement as in the prior methodology, one preloads the specimen and increases the applied load at the specified rate (see Figure 1). One might expect the preload to alter the results of the test and indeed it does, but fortunately, it is possible to account for the effect of the preload in interpreting the results. The accounting is done by calculating the normalized strength (defined as the strength in the presence of preload the strength in the absence of preload) as a function of (1) the preloading factor (defined as the preload stress the strength in the absence of preload) and (2) a SCG parameter, denoted n, that is used in a power-law crack-speed formulation. Figure 2 presents numerical results from this theoretical calculation.

  4. Reproduction of natural corrosion by accelerated laboratory testing methods

    SciTech Connect

    Luo, J.S.; Wronkiewicz, D.J.; Mazer, J.J.; Bates, J.K.

    1996-05-01

    Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms.

  5. Test of the law of gravitation at small accelerations

    NASA Astrophysics Data System (ADS)

    Meyer, H.; Lohrmann, E.; Schubert, S.; Bartel, W.; Glazov, A.; Löhr, B.; Niebuhr, C.; Wünsch, E.; Jönsson, L.; Kempf, G.

    2012-10-01

    Newton's Law of Gravitation has been tested at small values a of the acceleration, down to a ? 10-10 ms-2, the approximate value of MOND's constant a 0. Within experimental errors no deviations from Newton's Law were found. A comparison with six versions of the MOND interpolation function is given. Under the assumptions made in this paper one of the versions can be excluded.

  6. Testing in a combined vibration and acceleration environment.

    SciTech Connect

    Jepsen, Richard Alan; Romero, Edward F.

    2004-10-01

    Sandia National Laboratories has previously tested a capability to impose a 7.5 g-rms (30 g peak) radial vibration load up to 2 kHz on a 25 lb object with superimposed 50 g acceleration at its centrifuge facility. This was accomplished by attaching a 3,000 lb Unholtz-Dickie mechanical shaker at the end of the centrifuge arm to create a 'Vibrafuge'. However, the combination of non-radial vibration directions, and linear accelerations higher than 50g's are currently not possible because of the load capabilities of the shaker and the stresses on the internal shaker components due to the combined centrifuge acceleration. Therefore, a new technique using amplified piezo-electric actuators has been developed to surpass the limitations of the mechanical shaker system. They are lightweight, modular and would overcome several limitations presented by the current shaker. They are 'scalable', that is, adding more piezo-electric units in parallel or in series can support larger-weight test articles or displacement/frequency regimes. In addition, the units could be mounted on the centrifuge arm in various configurations to provide a variety of input directions. The design along with test results will be presented to demonstrate the capabilities and limitations of the new piezo-electric Vibrafuge.

  7. Accelerator-driven neutron sources for fusion-materials testing

    SciTech Connect

    Lawrence, G.P.

    1991-01-01

    Several accelerator-driven neutron sources have been proposed for satisfying the requirements of a high-flux high-volume international fusion materials testing facility that could be built in the near future. This paper summarizes the features and projected performance for the three accelerator sources that are leading candidates for such a role and that are viewed by the International Energy Agency (IEA) as worthy of further evaluation. These are: (1) the d-Li source, in which 35-MeV deuteron beams are incident on flowing lithium targets, (2) the t-H{sub 2}O source, in which 21-MeV triton beams strike high-speed water jets, and (3) the Spallation source in which a 600-MeV proton beam bombards a heavy-metal target.

  8. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    SciTech Connect

    McGee, M.W.; Leibfritz, J.; Martinez, A.; Pischalnikov, Y.; Schappert, W.; /Fermilab

    2011-03-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule No.1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  9. Database requirements for the Advanced Test Accelerator project

    SciTech Connect

    Chambers, F.W.

    1984-11-05

    The database requirements for the Advanced Test Accelerator (ATA) project are outlined. ATA is a state-of-the-art electron accelerator capable of producing energetic (50 million electron volt), high current (10,000 ampere), short pulse (70 billionths of a second) beams of electrons for a wide variety of applications. Databasing is required for two applications. First, the description of the configuration of facility itself requires an extended database. Second, experimental data gathered from the facility must be organized and managed to insure its full utilization. The two applications are intimately related since the acquisition and analysis of experimental data requires knowledge of the system configuration. This report reviews the needs of the ATA program and current implementation, intentions, and desires. These database applications have several unique aspects which are of interest and will be highlighted. The features desired in an ultimate database system are outlined. 3 references, 5 figures.

  10. Ultra-accelerated natural sunlight exposure testing facilities

    DOEpatents

    Lewandowski, Allan A.; Jorgensen, Gary J.

    2003-08-12

    A multi-faceted concentrator apparatus for providing ultra-accelerated natural sunlight exposure testing for sample materials under controlled weathering conditions comprising: facets that receive incident natural sunlight, transmits VIS/NIR and reflects UV/VIS to deliver a uniform flux of UV/VIS onto a sample exposure plane located near a center of a facet array in chamber means that provide concurrent levels of temperature and/or relative humidity at high levels of up to 100.times. of natural sunlight that allow sample materials to be subjected to accelerated irradiance exposure factors for a significant period of time of about 3 to 10 days to provide a corresponding time of about at least a years worth representative weathering of sample materials.

  11. Ultra-Accelerated Natural Sunlight Exposure Testing Facilities

    DOEpatents

    Lewandowski, Allan A. (Evergreen, CO); Jorgensen, Gary J. (Pine, CO)

    2004-11-23

    A multi-faceted concentrator apparatus for providing ultra-accelerated natural sunlight exposure testing for sample materials under controlled weathering conditions comprising: facets that receive incident natural sunlight, transmits VIS/NIR and reflects UV/VIS onto a secondary reflector that delivers a uniform flux of UV/VIS onto a sample exposure plane located near a center of a facet array in a chamber that provide concurrent levels of temperature and/or relative humidity at high levels of up to 100.times. of natural sunlight that allow sample materials to be subjected to accelerated irradiance exposure factors for a significant period of time of about 3 to 10 days to provide a corresponding time of about at least a years worth representative weathering of sample materials.

  12. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    E-print Network

    McGee, M W; Martinez, A; Pischalnikov, Y; Schappert, W

    2012-01-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule #1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  13. Beam loading and cavity compensation for the ground test accelerator

    SciTech Connect

    Jachim, S.P.; Natter, E.F.

    1989-01-01

    The Ground Test Accelerator (GTA) will be a heavily beam-loaded H/sup minus/ linac with tight tolerances on accelerating field parameters. The methods used in modeling the effects of beam loading in this machine are described. The response of the cavity to both beam and radio-frequency (RF) drive stimulus is derived, including the effects of cavity detuning. This derivation is not restricted to a small-signal approximation. An analytical method for synthesizing a predistortion network that decouples the amplitude and phase responses of the cavity is also outlined. Simulation of performance, including beam loading, is achieved through use of a control system analysis software package. A straightforward method is presented for extrapolating this work to model large coupled structures with closely spaced parasitic modes. Results to date have enabled the RF control system designs for GTA to be optimized and have given insight into their operation. 6 refs., 10 figs.

  14. Instrumentation for accelerated life tests of concentrator solar cells.

    PubMed

    Núñez, N; Vázquez, M; González, J R; Jiménez, F J; Bautista, J

    2011-02-01

    Concentrator photovoltaic is an emergent technology that may be a good economical and efficient alternative for the generation of electricity at a competitive cost. However, the reliability of these new solar cells and systems is still an open issue due to the high-irradiation level they are subjected to as well as the electrical and thermal stresses that they are expected to endure. To evaluate the reliability in a short period of time, accelerated aging tests are essential. Thermal aging tests for concentrator photovoltaic solar cells and systems under illumination are not available because no technical solution to the problem of reaching the working concentration inside a climatic chamber has been available. This work presents an automatic instrumentation system that overcomes the aforementioned limitation. Working conditions have been simulated by forward biasing the solar cells to the current they would handle at the working concentration (in this case, 700 and 1050 times the irradiance at one standard sun). The instrumentation system has been deployed for more than 10?000 h in a thermal aging test for III-V concentrator solar cells, in which the generated power evolution at different temperatures has been monitored. As a result of this test, the acceleration factor has been calculated, thus allowing for the degradation evolution at any temperature in addition to normal working conditions to be obtained. PMID:21361622

  15. Improved Accelerated Stress Tests Based on Fuel Cell Vehicle Data

    SciTech Connect

    Patterson, Timothy [Research Engineer] [Research Engineer; Motupally, Sathya [Research Engineer] [Research Engineer

    2012-06-01

    UTC will led a top-tier team of industry and national laboratory participants to update and improve DOE’s Accelerated Stress Tests (AST’s) for hydrogen fuel cells. This in-depth investigation will focused on critical fuel cell components (e.g. membrane electrode assemblies - MEA) whose durability represented barriers for widespread commercialization of hydrogen fuel cell technology. UTC had access to MEA materials that had accrued significant load time under real-world conditions in PureMotion® 120 power plant used in transit buses. These materials are referred to as end-of-life (EOL) components in the rest of this document. Advanced characterization techniques were used to evaluate degradation mode progress using these critical cell components extracted from both bus power plants and corresponding materials tested using the DOE AST’s. These techniques were applied to samples at beginning-of-life (BOL) to serve as a baseline. These comparisons advised the progress of the various failure modes that these critical components were subjected to, such as membrane degradation, catalyst support corrosion, platinum group metal dissolution, and others. Gaps in the existing ASTs predicted the degradation observed in the field in terms of these modes were outlined. Using the gaps, new AST’s were recommended and tested to better reflect the degradation modes seen in field operation. Also, BOL components were degraded in a test vehicle at UTC designed to accelerate the bus field operation.

  16. Design of accelerated life testing using proportional hazards-proportional odds

    Microsoft Academic Search

    Tingting Huang; Tongmin Jiang

    2010-01-01

    D-optimality is adopted in the optimum design of accelerated life testing in recent years. However, for some cases, the optimization results tend to approach the extreme stress levels and processing accelerated life testing under such stress levels would not obtain much information about lifetime and reliability of the test units. This paper presents an optimum design of constant stress accelerated

  17. Accelerated testing for cosmic soft-error rate

    SciTech Connect

    Ziegler, J.F.; Muhlfeld, H.P.; Montrose, C.J.; Curtis, H.W.; O`Gorman, T.J.; Ross, J.M.

    1996-01-01

    This paper describes the experimental techniques which have been developed at IBM to determine the sensitivity of electronic circuits to cosmic rays at sea level. It relates IBM circuit design and modeling, chip manufacture with process variations, and chip testing for SER sensitivity. This vertical integration from design to final test and with feedback to design allows a complete picture of LSI sensitivity to cosmic rays. Since advanced computers are designed with LSI chips long before the chips have been fabricated, and the system architecture is fully formed before the first chips are functional, it is essential to establish the chip reliability as early as possible. This paper establishes techniques to test chips that are only partly functional (e.g., only 1Mb of a 16Mb memory may be working) and can establish chip soft-error upset rates before final chip manufacturing begins. Simple relationships derived from measurement of more than 80 different chips manufactured over 20 years allow total cosmic soft-error rate (SER) to be estimated after only limited testing. Comparisons between these accelerated test results and similar tests determined by ``field testing`` (which may require a year or more of testing after manufacturing begins) show that the experimental techniques are accurate to a factor of 2.

  18. Using Uncertainty Analysis to Guide the Development of Accelerated Stress Tests (Presentation)

    SciTech Connect

    Kempe, M.

    2014-03-01

    Extrapolation of accelerated testing to the long-term results expected in the field has uncertainty associated with the acceleration factors and the range of possible stresses in the field. When multiple stresses (such as temperature and humidity) can be used to increase the acceleration, the uncertainty may be reduced according to which stress factors are used to accelerate the degradation.

  19. Study on the accelerated soakage testing during the reliability evaluation of plastic package

    Microsoft Academic Search

    Qian Min; Yang Cuijun; Yuan Hua; Cao Yunpeng

    2010-01-01

    In the semiconductor industry, during the component level reliability evaluation, the non-accelerated soakage testing in the precondition is normally proceeded, which takes much time. In order to reduce the soaking time, three accelerated soaking conditions are studied with reference to non-accelerated soaking condition (JEDEC Level 3 and JEITA Rank E). Under the three accelerated soaking conditions, the moisture gain and

  20. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    SciTech Connect

    Andrei Seryi

    2009-09-09

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  1. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema

    Andrei Seryi

    2010-01-08

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  2. Metal and elastomer seal tests for accelerator applications

    SciTech Connect

    Welch, K.M.; McIntyre, G.T.; Tuozzolo, J.E.; Skelton, R.; Pate, D.J.; Gill, S.M.

    1989-01-01

    The vacuum system of the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory has more than a thousand metal vacuum seals. Also, numerous elastomer seals are used throughout the AGS to seal large beam component chambers. An accelerator upgrade program is being implemented to reduce the AGS operating pressure by x100 and improve the reliability of the vacuum system. This paper describes work in progress on metal and elastomer vacuum seals to help meet those two objectives. Tests are reported on the sealing properties of a variety of metal seals used on different sealing surfaces. Results are also given on reversible sorption properties of certain elastomers. 16 refs., 6 figs., 4 tabs.

  3. Evaluation of accelerated stability test conditions for medicated chewing gums.

    PubMed

    Maggi, Lauretta; Conte, Ubaldo; Nhamias, Alain; Grenier, Pascal; Vergnault, Guy

    2013-10-01

    The overall stability of medicated chewing gums is investigated under different storage conditions. Active substances with different chemical stabilities in solid state are chosen as model drugs. The dosage form is a three layer tablet obtained by direct compression. The gum core contains the active ingredient while the external layers are formulated to prevent gum adhesion to the punches of the tableting machine. Two accelerated test conditions (40°C/75% RH and 30°C/65% RH) are performed for 6 months. Furthermore, a long-term stability test at room conditions is conducted to verify the predictability of the results obtained from the stress tests. Some drugs are stable in all the conditions tested, but other drugs, generally considered stable in solid dosage forms, have shown relevant stability problems particularly when stress test conditions are applied to this particular semi-solid dosage forms. For less stable drugs, the stress conditions of 40°C/75% RH are not always predictable of chewing gum stability at room temperature and may produce false negative; intermediate conditions, 30°C/65% RH, are more predictive for this purpose, the results of drug content found after 6 months at intermediate stress conditions and 12 months at room conditions are generally comparable. But the results obtained show that only long-term conditions stability tests gave consistent results. During aging, the semi solid nature of the gum base itself, may also influence the drug delivery rate during chewing and great attention should be given also to the dissolution stability. PMID:22794248

  4. Performance of the CREAM calorimeter in accelerator beam test

    E-print Network

    Yoon, Y S; Bagliesi, M G; Bigongiari, G; Ganel, O; Han, J H; Hyun, H J; Jeon, J A; Kang, T G; Kim, H J; Kim, K C; Lee, J K; Lee, M H; Lutz, L; Maestro, P; Malinine, A; Marrocchesi, P S; Nam, S W; Park, H; Park, I H; Park, N H; Seo, E S; Sina, R; Wu, J; Yang, J; Zei, R; Zinn, S Y

    2010-01-01

    The CREAM calorimeter, designed to measure the spectra of cosmic-ray nuclei from under 1 TeV to 1000 TeV, is a 20 radiation length (X0) deep sampling calorimeter. The calorimeter is comprised of 20 layers of tungsten interleaved with 20 layers of scintillating fiber ribbons, and is preceded by a pair of graphite interaction targets providing about 0.42 proton interaction lengths (\\lambda int). The calorimeter was placed in one of CERN's SPS accelerator beams for calibration and testing. Beams of 150 GeV electrons were used for calibration, and a variety of electron, proton, and nuclear fragment beams were used to test the simulation model of the detector. In this paper we discuss the performance of the calorimeter in the electron beam and compare electron beam data with simulation results.

  5. Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

    NASA Technical Reports Server (NTRS)

    Hoffman, David J.; Scheiman, David A.

    1996-01-01

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

  6. High-energy lattice for first-beam operation of the SRF test accelerator at NML

    SciTech Connect

    Prokop, C.; /NICADD, DeKalb; Piot, P.; /NICADD, DeKalb /Fermilab; Church, M.; /Fermilab

    2011-09-01

    The Superconducting Radio Frequency Test Accelerator, a linear electron accelerator currently in construction at Fermilab's New Muon Laboratory, will eventually reach energies of {approx} 900 MeV using four ILC-type superconducting accelerating cryomodules. The accelerator's construction is staged according to cryomodules availability. The first phase that will support first beam operation incorporates one cryomodule. In this Note, we summarize a possible design for the first-beam accelerator configuration.

  7. The research of reliability and accelerated life tests method of oil-line pumps

    Microsoft Academic Search

    Pingping Zhang; Jiansheng Lu; Zengliang Zhang; Boling Hu

    1992-01-01

    Mechanical pumps are used to show how to determine the useful life of a product and its corresponding reliability characteristic values and acceleration coefficient by means of constant stress accelerated life testing. The existing difficulties of lengthy life test time, high test cost, and unknown reliability indices are then resolved. The overall period of life test time has been shortened

  8. Integration Test of the High Voltage Hall Accelerator System Components

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Dankanich, John

    2013-01-01

    NASA Glenn Research Center is developing a 4 kilowatt-class Hall propulsion system for implementation in NASA science missions. NASA science mission performance analysis was completed using the latest high voltage Hall accelerator (HiVHAc) and Aerojet-Rocketdyne's state-of-the-art BPT-4000 Hall thruster performance curves. Mission analysis results indicated that the HiVHAc thruster out performs the BPT-4000 thruster for all but one of the missions studied. Tests of the HiVHAc system major components were performed. Performance evaluation of the HiVHAc thruster at NASA Glenn's vacuum facility 5 indicated that thruster performance was lower than performance levels attained during tests in vacuum facility 12 due to the lower background pressures attained during vacuum facility 5 tests when compared to vacuum facility 12. Voltage-Current characterization of the HiVHAc thruster in vacuum facility 5 showed that the HiVHAc thruster can operate stably for a wide range of anode flow rates for discharge voltages between 250 and 600 volts. A Colorado Power Electronics enhanced brassboard power processing unit was tested in vacuum for 1,500 hours and the unit demonstrated discharge module efficiency of 96.3% at 3.9 kilowatts and 650 volts. Stand-alone open and closed loop tests of a VACCO TRL 6 xenon flow control module were also performed. An integrated test of the HiVHAc thruster, brassboard power processing unit, and xenon flow control module was performed and confirmed that integrated operation of the HiVHAc system major components. Future plans include continuing the maturation of the HiVHAc system major components and the performance of a single-string integration test.

  9. Vibrational Stability of SRF Accelerator Test Facility at Fermilab

    SciTech Connect

    McGee, M.W.; Volk, J.T.; /Fermilab

    2009-05-01

    Recently developed, the Superconducting Radio Frequency (SRF) Accelerator Test Facilities at Fermilab support the International Linear Collider (ILC), High Intensity Neutrino Source (HINS), a new high intensity injector (Project X) and other future machines. These facilities; Meson Detector Building (MDB) and New Muon Lab (NML) have very different foundations, structures, relative elevations with respect to grade level and surrounding soil composition. Also, there are differences in the operating equipment and their proximity to the primary machine. All the future machines have stringent operational stability requirements. The present study examines both near-field and ambient vibration in order to develop an understanding of the potential contribution of near-field sources (e.g. compressors, ultra-high and standard vacuum equipment, klystrons, modulators, utility fans and pumps) and distant noise sources to the overall system displacements. Facility vibration measurement results and methods of possible isolation from noise sources are presented and discussed.

  10. The Status of Turkish Accelerator Center Test Facility

    SciTech Connect

    Yavas, Oe. [University of Ankara, Fac. of Engineering, Dept. of Engineering Physics, Tandogan 06100, Ankara (Turkey)

    2007-04-23

    Recently, conceptual design of Turkic Accelerator Center (TAC) proposal was completed. Main goal of this proposal is a charm factory that consists of a linac-ring type electron-positron collider. In addition, synchrotron radiation from the positron ring and free electron laser from the electron linac are proposed. The project related with this proposal has been accepted by Turkish government. It is planned that the Technical Design Report of TAC will have been written in next three years. In this period, an infrared oscillator free electron laser (IR FEL) will be constructed as a test facility for TAC. 20 and 50 MeV electron energies will be used to obtain infra red free electron laser. The main parameters of the electron linac, the optical cavities and the free electron laser were determined. The possible use of obtained laser beam in basic and applied research areas such as biotechnology, nanotechnology, semiconductors and photo chemistry were stated.

  11. The Status of Turkish Accelerator Center Test Facility

    NASA Astrophysics Data System (ADS)

    Yava?, Ö.

    2007-04-01

    Recently, conceptual design of Turkic Accelerator Center (TAC) proposal was completed. Main goal of this proposal is a charm factory that consists of a linac-ring type electron-positron collider. In addition, synchrotron radiation from the positron ring and free electron laser from the electron linac are proposed. The project related with this proposal has been accepted by Turkish government. It is planned that the Technical Design Report of TAC will have been written in next three years. In this period, an infrared oscillator free electron laser (IR FEL) will be constructed as a test facility for TAC. 20 and 50 MeV electron energies will be used to obtain infra red free electron laser. The main parameters of the electron linac, the optical cavities and the free electron laser were determined. The possible use of obtained laser beam in basic and applied research areas such as biotechnology, nanotechnology, semiconductors and photo chemistry were stated.

  12. A flexible and configurable system to test accelerator magnets

    SciTech Connect

    Jerzy M. Nogiec et al.

    2001-07-20

    Fermilab's accelerator magnet R and D programs, including production of superconducting high gradient quadrupoles for the LHC insertion regions, require rigorous yet flexible magnetic measurement systems. Measurement systems must be capable of handling various types of hardware and extensible to all measurement technologies and analysis algorithms. A tailorable software system that satisfies these requirements is discussed. This single system, capable of distributed parallel signal processing, is built on top of a flexible component-based framework that allows for easy reconfiguration and run-time modification. Both core and domain-specific components can be assembled into various magnet test or analysis systems. The system configured to comprise a rotating coil harmonics measurement is presented. Technologies as Java, OODB, XML, JavaBeans, software bus and component-based architectures are used.

  13. The use of accelerated radiation testing for avionics

    NASA Astrophysics Data System (ADS)

    Quinn, Heather

    2013-04-01

    In recent years, the use of unmanned aerial vehicles (UAVs) for military and national security applications has been increasing. One possible use of these vehicles is as remote sensing platforms, where the UAV carries several sensors to provide real-time information about biological, chemical or radiological agents that might have been released into the environment. One such UAV, the Global Hawk, has a payload space that can carry nearly one ton of sensing equipment, which makes these platforms significantly larger than many satellites. Given the size of the potential payload and the heightened radiation environment at high altitudes, these systems could be affected by the radiation-induced failure mechanisms from the naturally occurring terrestrial environment. In this paper, we will explore the use of accelerated radiation testing to prepare UAV payloads for deployment.

  14. Step-Stress Accelerated Degradation Testing (SSADT) for Photovoltaic (PV) Devices and Cells (Presentation)

    SciTech Connect

    Lee, J.; Elmore, R.; Suh, C.; Jones, W.

    2010-10-01

    Presentation on step-stress accelerated degradation testing (SSADT) for photovoltaics (PV). Developed are a step-stress degradation test (SSADT) for PV reliability tests and a lifetime prediction model for PV products.

  15. Outdoor weathering of PV modules — Effects of various climates and comparison with accelerated laboratory testing

    Microsoft Academic Search

    W. Herrmann; N. Bogdanski

    2011-01-01

    Understanding the degradation behavior of PV modules during long-term operation and developing realistic and effective procedures for accelerated testing that can simulate 25 years of operation requires a reliable database for outdoor weathering and for accelerated testing in the laboratory. To assess the effects of real-life weathering, we set up four test sites covering a wide range of climatic effects

  16. Effect of time and temperature on accelerated chemical durability tests made on commercial glass bottles

    Microsoft Academic Search

    Frank R. Bacon; O. G. Burch

    1940-01-01

    Chemical durability results obtained by tests on crushed samples and bottle surfaces on a variety of commercial glass-bottle compositions show the difficulties encountered in attempting to correlate accelerated tests with the actural performance of the bottles toward various solutions under service conditions. The results obtained thus far indicate that the value of accelerated tests conducted with distilled water as a

  17. Study on feasibility of storage accelerated testing based on parameter degradation for aerospace relays

    Microsoft Academic Search

    Zhaobin Wangl; Guofu Zhail; Xiaoyi Huang; Xuerong Ye

    2012-01-01

    It is difficult to obtain the failure data of long-lifetime and high-reliability aerospace relays, even based on the traditional storage accelerated life testing method. Aiming at this issue, based on the reliability test, the feasibility of accelerated degradation test for aerospace relays was studied. The performance degradation mechanism of the aerospace relays was analyzed during the storage and the possibility

  18. Research on Speed Robustness for Airborne Hydraulic Pump in the Circular Stress Accelerated Life Test

    Microsoft Academic Search

    Yong Sang; Zhanlin Wang

    2009-01-01

    According to the theory of the accelerated life test, a new accelerated life testing stand for airborne hydraulic pump has been developed recently. During the testing under the circular stress, speed character of the airborne hydraulic pump accompanied with vibration and noise of the gear box has become worse because gear backlash that often leads to collision in gear transmission

  19. Design of accelerated corrosion tests for electronic components in automotive applications

    Microsoft Academic Search

    Peter Eriksson; Bo Carlsson; I. O. Wallinder

    2001-01-01

    Two new accelerated laboratory corrosion tests for electronic components in automotive applications have been developed, based on the use of metallic copper as a meter for corrosivity. The accelerated tests are designed so that they reproduce the same kind of corrosion effects as observed with exposure of copper in real vehicle environments. The test cycle that best simulates the corrosion

  20. Accelerated indoor durability testing of polymeric photovoltaic encapsulation materials

    NASA Astrophysics Data System (ADS)

    Oreski, Gernot

    2010-08-01

    The aim of these investigations was to determine the influence of the relevant load parameters temperature and humidity on the degradation behavior of selected polymeric PV encapsulation materials. A test program concerning three accelerated artificial ageing tests was set up and a comprehensive study of the selected candidate materials and its degradation behavior was done. To assess the long term performance and durability of materials, it was necessary not only to measure the deterioration of macroscopic physical properties, but also to gain information about degradation processes taking place at a molecular level. Therefore, the material properties and the aging behaviour were characterized by infrared spectroscopy, by UV/VIS spectroscopy, by differential scanning calorimetry, by dynamical mechanical analysis and by tensile tests. By IR spectroscopy no significant thermal oxidation was detected for all investigated materials. But UV/VIS spectroscopy showed a significant drop in solar transmittance and reflectance values. Yellowing was observed due to the formation of chromophoric degradation products. For all materials a significant decrease in ultimate mechanical properties due to chemical aging was measured. For both backsheet materials the changes in ultimate mechanical properties can be attributed nearly exclusiveley to the polyester layer. On the other hand, a stiffening of all materials due to physical aging was observed within the first 1000h of damp heat testing. For the backsheet laminates, delamination at the edges was observed. Generally, higher temperature levels during exposure induced faster rate of chemical and physical aging. High humidity levels showed to be less influential on polymer degradation than temperature.

  1. Acceleration tests to determine salient pole synchronous motor inrush currents and torques

    Microsoft Academic Search

    J. H. Dymond; B. Mistry; R. Ong

    2002-01-01

    Determining torque and current at locked rotor and various slips during the acceleration test on a synchronous machine is very tedious and time consuming. Induction and synchronous machines behave similarly during acceleration except that synchronous machine acceleration can include a pulsation torque. Because of the salient poles, conditions exist where the synchronous motor has minimum torque at quadrature axis and

  2. Status and plans for a SRF accelerator test faciliy at Fermilab

    E-print Network

    Leibfritz, J; Carlson, K; Chase, B; Church, M; Harms, E; Klebaner, A; Kucera, M; Lackey, S; Martinez, A; Nagaitsev, S; Nobrega, L; Piot, P; Reid, J; Wendt, M; Wesseln, S

    2012-01-01

    A superconducting RF accelerator test facility is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beam lines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating an 810 MeV electron beam with ILC beam intensity. Expansion plans of the facility are underway that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. In addition to testing accelerator components, this facility will be used to test RF power equipment, instrumentation, LLRF and controls systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

  3. Integration of NDT into life time management

    Microsoft Academic Search

    R. Becker; G. Dobmann; M. Kröning; H. Reiter; E. Schneider

    1997-01-01

    Being a life management tool, non-destructive testing is designed to detect defects in components before they become critical under load. Non-destructive testing has consequently become a well-established technique to ensure the safe and economic operation of pressurised components. However, life assessment and prediction requires knowledge about load conditions and history and material degradation along with a quantitative defect state evaluation.

  4. Framework for a Comparative Accelerated Testing Standard for PV Modules: Preprint

    SciTech Connect

    Kurtz, S.; Wohlgemuth, J.; Yamamichi, M.; Sample, T.; Miller, D.; Meakin, D.; Monokroussos, C.; TamizhMani, M.; Kempe, M.; Jordan, D.; Bosco, N.; Hacke, P.; Bermudez, V.; Kondo, M.

    2013-08-01

    As the photovoltaic industry has grown, the interest in comparative accelerated testing has also grown. Private test labs offer testing services that apply greater stress than the standard qualification tests as tools for differentiating products and for gaining increased confidence in long-term PV investments. While the value of a single international standard for comparative accelerated testing is widely acknowledged, the development of a consensus is difficult. This paper strives to identify a technical basis for a comparative standard.

  5. Demonstration recommendations for accelerated testing of concrete decontamination methods

    SciTech Connect

    Dickerson, K.S.; Ally, M.R.; Brown, C.H.; Morris, M.I.; Wilson-Nichols, M.J.

    1995-12-01

    A large number of aging US Department of Energy (DOE) surplus facilities located throughout the US require deactivation, decontamination, and decommissioning. Although several technologies are available commercially for concrete decontamination, emerging technologies with potential to reduce secondary waste and minimize the impact and risk to workers and the environment are needed. In response to these needs, the Accelerated Testing of Concrete Decontamination Methods project team described the nature and extent of contaminated concrete within the DOE complex and identified applicable emerging technologies. Existing information used to describe the nature and extent of contaminated concrete indicates that the most frequently occurring radiological contaminants are {sup 137}Cs, {sup 238}U (and its daughters), {sup 60}Co, {sup 90}Sr, and tritium. The total area of radionuclide-contaminated concrete within the DOE complex is estimated to be in the range of 7.9 {times} 10{sup 8} ft{sup 2}or approximately 18,000 acres. Concrete decontamination problems were matched with emerging technologies to recommend demonstrations considered to provide the most benefit to decontamination of concrete within the DOE complex. Emerging technologies with the most potential benefit were biological decontamination, electro-hydraulic scabbling, electrokinetics, and microwave scabbling.

  6. A normalization method for life-time prediction of composite materials

    E-print Network

    Paris-Sud XI, Université de

    dimensional normalization tech- nique. The first part of the article details the materials and testsA normalization method for life-time prediction of composite materials M. Darwichea , G. Bousalehb is to predict the rupture of specimens of composite materials. During a creep experiment, with traction method

  7. Accelerators

    NSDL National Science Digital Library

    Lawrence Berkeley National Laboratory. Particle Data Group

    2002-01-01

    What is the purpose of particle accelerators? On this web page, part of a particle physics tutorial, students read that accelerators solve two problems. The accelerators provide an increase in momentum to produce particles of small wavelength, and the fast-moving particles can create new particles when smashed together. A photograph of the inside of a particle accelerator is provided. Copyright 2005 Eisenhower National Clearinghouse

  8. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate (dynamic fatigue) testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rates in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  9. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate ('dynamic fatigue') testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rate in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  10. Development of a 20-MeV Dielectric-Loaded Accelerator Test Facility

    SciTech Connect

    Gold, S.H.; Kinkead, A.K.; Gai, W.; Power, J.G.; Konecny, R.; Jing, C.G.; Tantawi, S.G.; Nantista, C.D.; Hu, Y.; Chen, H.; Tang, C.; Lin, Y.; Bruce, R.W.; Bruce, R.L.; Fliflet, A.W.; Lewis, D.; /Naval Research Lab, Wash., D.C. /LET Corp., Washington /Argonne /SLAC /Tsinghua U., Beijing

    2005-06-22

    This paper describes a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded accelerator (DLA) test facility powered by a high-power 11.424-GHz magnicon amplifier. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW. The facility will include a 5 MeV electron inector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to {approx} 8 MV/m. SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRl, is developing a means to join short ceramic sections into a continuous accelerator tube by ceramic brazing using an intense millimeter-wave beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year. The facility will be used for testing DLA structures using a variety of materials and configurations, and also for testing other X-band accelerator concepts. The initial goal is to produce a compact 20 MeV dielectric-loaded test accelerator.

  11. Study of reliability and accelerated life test of electric drive system

    Microsoft Academic Search

    Wu Ying; Kang Jinsong; Zhang Ye; Jing Shiyi; Hu Dabing

    2009-01-01

    Reliability is defined as the probability that an item can perform is intended function for a specified interval under stated conditions. This paper researches on the reliability and accelerated life test of electric drive system of Electric Vehicle. It provides three different cases of accelerated life testing, and builds the fault tree through analyzing the construction and failure mechanism of

  12. Strategy for designing accelerated aging tests to evaluate IGBT power modules lifetime in real operation mode

    Microsoft Academic Search

    Jean-Marc Thébaud; Eric Woirgard; Christian Zardini; Stéphane Azzopardi; Olivier Briat; Jean-Michel Vinassa

    2003-01-01

    Accelerated aging tests are widely used in electronics industry to validate the technological choices of packaging, especially when significant lifetime is required. The thermal coefficient of expansion mismatch between the soldered materials results in crack propagation in the solder joints, which irreversibly increases the thermal resistance of the assembly and progressively leads to the failure of the module. Accelerated testing

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

    NASA Technical Reports Server (NTRS)

    Frickland, P. O.; Repar, J.

    1982-01-01

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

  14. Compact X-ray source at STF (Super Conducting Accelerator Test Facility)

    NASA Astrophysics Data System (ADS)

    Urakawa, J.

    2012-05-01

    KEK-STF is a super conducting linear accelerator test facility for developing accelerator technologies for the ILC (International Linear Collider). We are supported in developing advanced accelerator technologies using STF by Japanese Ministry (MEXT) for Compact high brightness X-ray source development. Since we are required to demonstrate the generation of high brightness X-ray based on inverse Compton scattering using super conducting linear accelerator and laser storage cavity technologies by October of next year (2012), the design has been fixed and the installation of accelerator components is under way. The necessary technology developments and the planned experiment are explained.

  15. Operational status of the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fischer, A.S.; Gallardo, J.; Jialin, Xie; Kirk, H.G.; Malone, R.G.; Parsa, Z.; Palmer, R.B.; Rao, T.; Rogers, J.; Sheehan, J.; Tsang, T.Y.F.; Ulc, S.; van Steenbergen, A.; Woodle, M.; Zhang, R.S. (Brookhaven National Lab., Upton, NY (USA)); Bigio, I.; Kurnit, N.; Shimada, T. (Los Alamos National Lab., NM (USA)); McDonald, K.T.; Russel, D.P. (Princeton Univ., NJ (USA)); Jiang,

    1990-01-01

    Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2{pi}/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures.

  16. Initial tests of compressed geometry acceleration tubes in the ORNL 25URC tandem accelerator

    Microsoft Academic Search

    C. M. Jones; K. A. Erb; D. L. Haynes; J. T. Mitchell; N. F. Ziegler; J. E. Raatz; R. D. Rathmell

    1986-01-01

    In an effort to further improve voltage performance of the ORNL 25URC accelerator, we are engaged in a program of replacing the original acceleration tubes with tubes of a compressed geometry design. In this design, which utilizes a modified NEC high-gradient 17-cm long tube section, the 3-cm thick heatable aperture assembly provided as part of the original installation is replaced

  17. Design and Simulation of IOTA - a Novel Concept of Integrable Optics Test Accelerator

    SciTech Connect

    Nagaitsev, S.; Valishev, A.; /Fermilab; Danilov, V.V.; /Oak Ridge; Shatilov, D.N.; /Novosibirsk, IYF

    2012-05-01

    The use of nonlinear lattices with large betatron tune spreads can increase instability and space charge thresholds due to improved Landau damping. Unfortunately, the majority of nonlinear accelerator lattices turn out to be nonintegrable, producing chaotic motion and a complex network of stable and unstable resonances. Recent advances in finding the integrable nonlinear accelerator lattices have led to a proposal to construct at Fermilab a test accelerator with strong nonlinear focusing which avoids resonances and chaotic particle motion. This presentation will outline the main challenges, theoretical design solutions and construction status of the Integrable Optics Test Accelerator (IOTA) underway at Fermilab.

  18. Particle Acceleration in three dimensional Reconnection Regions: A New Test Particle Approach

    E-print Network

    Rudiger Schopper; Guido T. Birk; Harald Lesch

    2001-06-29

    Magnetic Reconnection is an efficient and fast acceleration mechanism by means of direct electric field acceleration parallel to the magnetic field. Thus, acceleration of particles in reconnection regions is a very important topic in plasma astrophysics. This paper shows that the conventional analytical models and numerical test particle investigations can be misleading concerning the energy distribution of the accelerated particles, since they oversimplify the electric field structure by the assumption that the field is homogeneous. These investigations of the acceleration of charged test particles are extended by considering three-dimensional field configurations characterized by localized field-aligned electric fields. Moreover, effects of radiative losses are discussed. The comparison between homogeneous and inhomogeneous electric field acceleration in reconnection regions shows dramatic differences concerning both, the maximum particle energy and the form of the energy distribution.

  19. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing - Part 2

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerome C.; Kolody, Mark R.

    2012-01-01

    Evaluation of metals to predict service life of metal-based structures in corrosive environments has long relied on atmospheric exposure test sites. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions similar to those of the corrosive environment. Their reliability to correlate to atmospheric exposure test results is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated corrosion testing has yet to be universally accepted as a useful tool in predicting the long-term service life of a metal, despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard, and their use is crucial, a method that correlates timescales from accelerated testing to atmospheric exposure would be very valuable. This paper presents work that began with the characterization of the atmospheric environment at the Kennedy Space Center (KSC) Beachside Corrosion Test Site. The chemical changes that occur on low carbon steel, during atmospheric and accelerated corrosion conditions, were investigated using surface chemistry analytical methods. The corrosion rates and behaviors of panels subjected to long-term and accelerated corrosion conditions, involving neutral salt fog and alternating seawater spray, were compared to identify possible timescale correlations between accelerated and long-term corrosion performance. The results, as well as preliminary findings on the correlation investigation, are presented.

  20. Acceleration

    Microsoft Academic Search

    Edward Geoghegan

    1897-01-01

    IN NATURE, NO. 1415, p. 125, Prof. Lodge asserts that the subject of acceleration is at the root of the perennial debate between engineers and teachers of mechanics; and he urges clearness of idea and accuracy of speech on all who deal with the junior student. Towards this end I would suggest that the too common phrase ``acceleration of velocity''

  1. Characteristics of Accelerated Fatigue Tests by Cyclic Flexion of SMT PC boards

    Microsoft Academic Search

    Zdzislaw Drozd; Marcin Szwech; Rafal Wrona

    2006-01-01

    The critical problem by implementation the EU RoHS directive is assurance of existing level of electronic products reliability. For accelerated reliability testing of soldered joints was developed the test stand for mechanical cycling. The test samples of printed circuits with soldered components are bent with constant radius at all length of the printed circuit. Some information about mechanical testing of

  2. Testing of Composite Fan Vanes With Erosion-Resistant Coating Accelerated

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Sutter, James K.; Otten, Kim D.; Samorezov, Sergey; Perusek, Gail P.

    2004-01-01

    The high-cycle fatigue of composite stator vanes provided an accelerated life-state prior to insertion in a test stand engine. The accelerated testing was performed in the Structural Dynamics Laboratory at the NASA Glenn Research Center under the guidance of Structural Mechanics and Dynamics Branch personnel. Previous research on fixturing and test procedures developed at Glenn determined that engine vibratory conditions could be simulated for polymer matrix composite vanes by using the excitation of a combined slip table and electrodynamic shaker in Glenn's Structural Dynamics Laboratory. Bench-top testing gave researchers the confidence to test the coated vanes in a full-scale engine test.

  3. Mechanism of mark deformation in phase-change media tested in an accelerated environment

    NASA Astrophysics Data System (ADS)

    Hirotsune, Akemi; Terao, Motoyasu; Miyauchi, Yasushi; Tokushuku, Nobuhiro; Tamura, Reiji

    2007-04-01

    Increased jitter caused by recording marks becoming deformed in an accelerated environmental test was investigated and a model where the change in the speed of crystallization is affected by passive oxidation on the amorphous surface of the recording layer was devised. The model clarified the mechanism by which deformation in the marks caused increased jitter in the accelerated environmental test. Adding nitrogen into the gas when sputtering the protective layer adjacent to the recording film was investigated. It was confirmed that a prototype disk with this protective layer has decreased jitter after a 500 h accelerated test and superior power margins.

  4. Study of decoupling control for airborne hydraulic pump in the cyclic stress accelerated life test

    Microsoft Academic Search

    Mingxia Wang; Zhaoqin Peng; Yongling Fu; Xin Wang

    2009-01-01

    Based on the characteristics of stress change for the cyclic stress accelerated life testing (ALT) for the airborne hydraulic and ensured the accuracy acceleration model is established based on the pressure stress; the coupling relationship between the pressure subsystem and the rotation speed subsystem is analyzed. The coupling relationship will have cause a problem on the rotation speed with the

  5. GENERATION AND ANALYSIS OF SUBPICOSECOND DOUBLE ELECTRON BUNCH AT THE BROOKHAVEN ACCELERATOR TEST

    E-print Network

    Brookhaven National Laboratory

    GENERATION AND ANALYSIS OF SUBPICOSECOND DOUBLE ELECTRON BUNCH AT THE BROOKHAVEN ACCELERATOR TEST Accelerator Center, Stanford, CA 94025, USA Abstract Two compressed electron beam bunches from a single 60-MeV bunch have been generated in a reproducible manner during compression in the magnetic chicane - "dog leg

  6. Meson Life Time in the Anisotropic Quark-Gluon Plasma

    E-print Network

    Mohammad Ali-Akbari; Davood Allahbakhshi

    2014-08-20

    In the hot (an)isotropic plasma the meson life time $\\tau$ is defined as a time scale after which the meson dissociates. According to the gauge/gravity duality, this time can be identified with the inverse of the imaginary part of the frequency of the quasinormal modes, $\\omega_I$, in the (an)isotropic black hole background. In the high temperature limit, we numerically show that at fixed temperature(entropy density) the life time of the mesons decreases(increases) as the anisotropy parameter raises. For general case, at fixed temperature we introduce a polynomial function for $\\omega_I$ and observe that the meson life time decreases. Moreover, we realize that $(s/T^3)^6$, where $s$ and $T$ are entropy density and temperature of the plasma respectively, can be expressed as a function of anisotropy parameter over temperature. Interestingly, this function is a Pad\\'{e} approximant.

  7. Analysis of Transmitted Optical Spectrum Enabling Accelerated Testing of CPV Designs: Preprint

    SciTech Connect

    Miller, D. C.; Kempe, M. D.; Kennedy, C. E.; Kurtz, S. R.

    2009-07-01

    Reliability of CPV systems' materials is not well known; methods for accelerated UV testing have not been developed. UV and IR spectra transmitted through representative optical systems are evaluated.

  8. Applications of the ram accelerator to hypervelocity aerothermodynamic testing

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Knowlen, C.; Hertzberg, A.

    1992-01-01

    A ram accelerator used as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerodynamics research is presented. It is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled down a stationary tube filled with a tailored combustible gas mixture. Ram accelerator operation has been demonstrated at 39 mm and 90 mm bores, supporting the proposition that this launcher concept can be scaled up to very large bore diameters of the order of 30-60 cm. It is concluded that high quality data obtained from the tube wall and projectile during the aceleration process itself are very useful for understanding aerothermodynamics of hypersonic flow in general, and for providing important CFD validation benchmarks.

  9. Operational status of the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Ben-Zvi, I.; Chou, T.S.; Fernow, R.C.; Fischer, J.; Gallarado, J.; Kirk, H.G.; Palmer, R.B.; Pellegrini, C.; Sheehan, J.; Srinivasan-Rao, T.; Ulc, S.; Van Steenbergen, A.; Woodle, M.; Biglio, I.; Kurnit, N.; McDonald, K.T. (Brookhaven National Lab., Upton, NY (USA); Los Alamos National Lab., NM (USA); Princeton Univ., NJ (USA). Dept. of Physics)

    1989-01-01

    Design and operation of a 50 MeV Electron Linear Accelerator utilizing a low emittance ({gamma} {var epsilon} = 5 to 10 mm-mrad) radio frequency gun operating at an output energy of 5 MeV and a charge of 1 nC is described. Design calculations and early radio frequency measurements and operational experience with the electron gun utilizing a dummy copper cathode in place of the proposed photocathode emitter are given. 6 refs., 9 figs., 1 tab.

  10. Accelerated life-tests for intermittent destructive inspection, with logistic failure-distribution

    Microsoft Academic Search

    So Young Sohn

    1997-01-01

    Statistically-optimal accelerated life-test plans are suggested for items whose lifetime follows a logistic distribution. Both the scale and location parameters of the lifetime distribution are functions of the stress level. The test plans accommodate intermittent destructive sampling. The number of sampled items which fail to pass the test at the time of each inspection follows a hypergeometric distribution; the number

  11. Calibration of rotational acceleration for the rotarod test of rodent motor coordination

    PubMed Central

    Bohlen, Martin; Cameron, Andy; Metten, Pamela; Crabbe, John C.; Wahlsten, Douglas

    2015-01-01

    The latency of mice and rats to fall from the accelerating rotarod can differ markedly between laboratories using the same brand of rod as well as between studies using different kinds of rods. These discrepancies can arise from different rod diameters, surface textures, test protocols, or laboratory environmental factors beyond the test itself, but it is also possible that the actual acceleration rates of the different rods do not correspond to the nominal rates set on the devices. This paper describes a simple method to measure acceleration rate of the rotarod and to set the rate to a desired value for any brand of rod. PMID:19041892

  12. Method for accelerated reliability tests of centrifugal compressors

    Microsoft Academic Search

    S. D. Medvedev; E. V. Krinitskii; A. G. Ovsienko; A. P. Usatenko

    1993-01-01

    The design of centrifugal compressors with a high level of reliability requires significant additional expenditures for verification of the efficiency of new scientific and technical decisions and involves carrying out expensive long-term test-unit or operating tests. The effectiveness of the tests increases significantly if their results can be used to evaluate the reliability of individual components and to determine in

  13. Status and Plans for an SRF Accelerator Test Facility at Fermilab

    E-print Network

    Church, M; Nagaitsev, S

    2012-01-01

    A superconducting RF accelerator test facility is currently under construction at Fermilab. The accelerator will consist of an electron gun, 40 MeV injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, and multiple downstream beam lines for testing diagnostics and performing beam experiments. With 3 cryomodules installed this facility will initially be capable of generating an 810 MeV electron beam with ILC beam intensity. The facility can accommodate up to 6 cryomodules for a total beam energy of 1.5 GeV. This facility will be used to test SRF cryomodules under high intensity beam conditions, RF power equipment, instrumentation, and LLRF and controls systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

  14. Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 1; Start-up

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Rogers, Paul; Hoff, Craig

    2000-01-01

    The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. They are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the first part of the experimental study, i.e. the effects of a centrifugal force on the LHP start-up. Tests were conducted by varying the heat load to the evaporator, sink temperature, magnitude and frequency of centrifugal force, and LHP orientation relative to the direction of the accelerating force. The accelerating force seems to have little effect on the loop start-up in terms of temperature overshoot and superheat at boiling incipience. Changes in these parameters seem to be stochastic with or without centrifugal accelerating forces. The LHP started successfully in all tests.

  15. Preliminary results from pressure tank test and field acceleration test of New-Profiling float of Japan (NINJA)

    Microsoft Academic Search

    K. Izawa; K. Ando; K. Mizuno; A. Inoue; N. Shikama; K. Takeuchi; M. Sekimoto

    2002-01-01

    As one of contributions of Japan to the international Argo community, one of Japanese ocean instrument manufacturers, Tsurumi Seiki Co. (TSK), has started the development of original profiling float in 2000. We purchased the four TSK floats in 2001, and performed the pressure tank test and the acceleration field test in the north Pacific. Among four floats, two are carrying

  16. Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 2; Temperature Stability

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Kaya, Taril; Rogers, Paul; Hoff, Craig

    2000-01-01

    The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. LHP's are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the second part of the experimental study, i.e. the effect of an accelerating force on the LHP operating temperature. It has been known that in stationary tests the LHP operating temperature is a function of the evaporator power and the condenser sink temperature when the compensation temperature is not actively controlled. Results of this test program indicate that any change in the accelerating force will result in a chance in the LHP operating temperature through its influence on the fluid distribution in the evaporator, condenser and compensation chamber. However, the effect is not universal, rather it is a function of other test conditions. A steady, constant acceleration may result in an increase or decrease of the operating temperature, while a periodic spin will lead to a quasi-steady operating temperature over a sufficient time interval. In addition, an accelerating force may lead to temperature hysteresis and changes in the temperature oscillation. In spite of all these effects, the LHP continued to operate without any problems in all tests.

  17. Enabling More than Moore: Accelerated Reliability Testing and Risk Analysis for Advanced Electronics Packaging

    NASA Technical Reports Server (NTRS)

    Ghaffarian, Reza; Evans, John W.

    2014-01-01

    For five decades, the semiconductor industry has distinguished itself by the rapid pace of improvement in miniaturization of electronics products-Moore's Law. Now, scaling hits a brick wall, a paradigm shift. The industry roadmaps recognized the scaling limitation and project that packaging technologies will meet further miniaturization needs or ak.a "More than Moore". This paper presents packaging technology trends and accelerated reliability testing methods currently being practiced. Then, it presents industry status on key advanced electronic packages, factors affecting accelerated solder joint reliability of area array packages, and IPC/JEDEC/Mil specifications for characterizations of assemblies under accelerated thermal and mechanical loading. Finally, it presents an examples demonstrating how Accelerated Testing and Analysis have been effectively employed in the development of complex spacecraft thereby reducing risk. Quantitative assessments necessarily involve the mathematics of probability and statistics. In addition, accelerated tests need to be designed which consider the desired risk posture and schedule for particular project. Such assessments relieve risks without imposing additional costs. and constraints that are not value added for a particular mission. Furthermore, in the course of development of complex systems, variances and defects will inevitably present themselves and require a decision concerning their disposition, necessitating quantitative assessments. In summary, this paper presents a comprehensive view point, from technology to systems, including the benefits and impact of accelerated testing in offsetting risk.

  18. Accelerated testing for cosmic soft-error rate

    Microsoft Academic Search

    James F. Ziegler; Hans P. Muhlfeld; Charles J. Montrose; Huntington W. Curtis; Timothy J. O'gorman; John M. Ross

    1996-01-01

    This paper describes the experimental techniques which have been developed at IBM to determine the sensitivity of electronic circuits to cosmic rays at sea level. It relates IBM circuit design and modeling, chip manufacture with process variations, and chip testing for SER sensitivity. This vertical integration from design to final test and with feedback to design allows a complete picture

  19. An Integration Testing Facility for the CERN Accelerator Controls System

    Microsoft Academic Search

    N Stapley; M Arruat; J C Bau; S Deghaye; C Dehavay; W Sliwinski; M Sobczak

    2009-01-01

    A major effort has been invested in the design, development, and deployment of the LHC Control System. This large control system is made up of a set of core components and dependencies, which although tested individually, are often not able to be tested together on a system capable of representing the complete control system environment, including hardware. Furthermore this control

  20. Accelerated vacuum testing of long life ball bearings and sliprings

    NASA Technical Reports Server (NTRS)

    Meeks, C. R.; Christy, R. I.; Cunningham, A. C.

    1971-01-01

    Extensive analytical studies and testing have been conducted on bearings and sliprings in vacuum at temperatures from 30 to 130 F. Thirty-six bearings lubricated with two types of oil were tested in vacuum of less than 10 to the minus 8th power torr at speeds from 55 to 180 rpm. Temperatures, load, speed, and oil viscosity were varied to evaluate the effects on life and wear. All bearings performed successfully during a 7-month test, and the potential merits of the two oils were compared. Over 25 different, dry-lubricated brush/slipring material combinations have been tested, with variations of brush and ring design and surface speed. Test results indicate the probability of 10 years or more of slipring and brush lifetime with properly designed brushes for 1-in.-diameter ring rotating at 60 rpm.

  1. Investigating the feasibility of temperature-controlled accelerated drug release testing for an intravaginal ring.

    PubMed

    Externbrink, Anna; Clark, Meredith R; Friend, David R; Klein, Sandra

    2013-11-01

    The objective of the present study was to investigate if temperature can be utilized to accelerate drug release from Nuvaring®, a reservoir type intravaginal ring based on polyethylene vinyl acetate copolymer that releases a constant dose of contraceptive steroids over a duration of 3 weeks. The reciprocating holder apparatus (USP 7) was utilized to determine real-time and accelerated etonogestrel release from ring segments. It was demonstrated that drug release increased with increasing temperature which can be attributed to enhanced drug diffusion. An Arrhenius relationship of the zero-order release constants was established, indicating that temperature is a valid parameter to accelerate drug release from this dosage form and that the release mechanism is maintained under these accelerated test conditions. Accelerated release tests are particularly useful for routine quality control to assist during batch release of extended release formulations that typically release the active over several weeks, months or even years, since they can increase the product shelf life. The accelerated method should therefore be able to discriminate between formulations with different release characteristics that can result from normal manufacturing variance. In the case of Nuvaring®, it is well known that the process parameters during the extrusion process strongly influence the polymeric structure. These changes in the polymeric structure can affect the permeability which, in turn, is reflected in the release properties. Results from this study indicate that changes in the polymeric structure can lead to a different temperature dependence of the release rate, and as a consequence, the accelerated method can become less sensitive to detect changes in the release properties. When the accelerated method is utilized during batch release, it is therefore important to take this possible restriction into account and to evaluate the accelerated method with samples from non-conforming batches that are explicitly "out of specification" under real-time test conditions. PMID:23791685

  2. Design and Factory Test of the E /E- Frascati Linear Accelerator for DAFNE

    SciTech Connect

    Anamkath, H.; Lyons, S.; Nett, D.; Treas, P.; Whitham, K.; Zante, T.; /Titan Beta, Dublin; Miller, R.; /Titan Beta, Dublin /SLAC; Boni, R.; Hsieh, H.; Sannibale, F.; Vescovi, M.; Vignola, G.; /Frascati

    2011-11-28

    The electron-positron accelerator for the DAFNE project has been built and is in test at Titan Beta in Dublin, CA. This S-Band RF linac system utilizes four 45 MW sledded klystrons and 16-3 m accelerating structures to achieve the required performance. It delivers a 4 ampere electron beam to the positron converter and accelerates the resulting positrons to 550 MeV. The converter design uses a 4.3T pulsed tapered flux compressor along with a pseudo-adiabatic tapered field to a 5 KG solenoid over the first two positron accelerating sections. Quadrupole focusing is used after 100 MeV. The system performance is given in Table 1. This paper briefly describes the design and development of the various subassemblies in this system and gives the initial factory test data.

  3. The static spacetime relative acceleration for the general free fall and its possible experimental test

    E-print Network

    F. Bunchaft; S. Carneiro

    1998-03-17

    Mishra has recently established, using a generic static metric, the relative local proper-time 3-acceleration of a test-particle in one-dimensional free fall relative to a static reference frame in any static spacetime. In this paper, on the grounds of gravitoelectromagnetism we establish, in a covariant spacetime form, the relative 4-acceleration for the general free fall, indicating its canonical representation with its 3-space cinematical content. Then we obtain the relation between this representation and the very known expression for the relative free fall acceleration in Fermi coordinates. Taking this into account, it is shown that an experiment with relativistic beams in a circular accelerator, modelled by Fermi coordinates, recently proposed by Moliner et al, can test the here established covariant result and, therefore, can also verify Mishra's formula. This possibility of experimental verification, besides its intrinsic importance, can answer a recent inquire by Vigier, related to his recent proposal of derivation of inertial forces.

  4. Test particle simulation of direct laser acceleration in a density-modulated plasma waveguide

    SciTech Connect

    Lin, M.-W.; Jovanovic, I. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2012-11-15

    Direct laser acceleration (DLA) of electrons by the use of the intense axial electric field of an ultrafast radially polarized laser pulse is a promising technique for future compact accelerators. Density-modulated plasma waveguides can be implemented for guiding the propagation of the laser pulse to extend the acceleration distance and for the quasi-phase-matching between the accelerated electrons and the laser pulse. A test particle model is developed to study the optimal axial density modulation structure of plasma waveguides for laser pulses to efficiently accelerate co-propagating electrons. A simple analytical approach is also presented, which can be used to estimate the energy gain in DLA. The analytical model is validated by the test particle simulation. The effect of injection phase and acceleration of electrons injected at various radial positions are studied. The results indicate that a positively chirped density modulation of the waveguide structure is required to accelerate electron with low initial energies, and can be effectively optimized. A wider tolerance on the injection phase and radial distance from the waveguide axis exists for electrons injected with a higher initial energy.

  5. Using Globular Clusters to Test Gravity in the Weak Acceleration Regime

    NASA Astrophysics Data System (ADS)

    Scarpa, Riccardo; Marconi, Gianni; Gilmozzi, Roberto; Carraro, Giovanni

    2007-06-01

    We report on the results from an ongoing programme aimed at testing Newton's law of gravity in the low acceleration regime using globular clusters. We find that all clusters studied so far behave like galaxies, that is, their velocity dispersion profiles flatten out at large radii where the acceleration of gravity goes below 10 8 cm s 2, instead of following the expected Keplerian fall-off. In galaxies this behaviour is ascribed to the existence of a dark matter halo. Globular clusters, however, are not supposed to contain dark matter, hence this result might indicate that our present understanding of gravity in the weak regime of accelerations is incomplete and possibly incorrect.

  6. Laboratory and Field Testing of Precast Bridge Elements Used for Accelerated Construction

    Microsoft Academic Search

    Vernon W. Wineland; F. Wayne Klaiber; Thomas P. Schoellen

    Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for use with accelerated construction. Individual components of the system have been tested in the Iowa State University Structural Laboratory, and the overall system was tested in the field. Using the BHC system, the bridge superstructure can be assembled in two days and the bridge opened to

  7. Direct Prediction Methods on Lifetime Distribution of Organic Light-Emitting Diodes From Accelerated Degradation Tests

    Microsoft Academic Search

    Jong In Park; Suk Joo Bae

    2010-01-01

    Accelerated degradation testing (ADT) expedites product degradation by stressing the product beyond its normal use. To extrapolate the product's reliability at use condition, the ADT requires a known functional link relating the harsh testing environment to the usual use environment. Practitioners are often faced with a great challenge to designate an explicit form of the stress-degradation relationship a priori in

  8. Hardware-Accelerated Ray-Triangle Intersection Testing for High-Performance Collision Detection

    Microsoft Academic Search

    Sung-Soo Kim; Seung-Woo Nam; Do-Hyung Kim; In-Ho Lee

    2007-01-01

    We present a novel approach for hardware-accelerated collision detection. This paper describes the design of the hardware architecture for primitive inference testing components implemented on a multi-FPGA Xilinx Virtex-II prototyping system. This paper focuses on the acceleration of ray-triangle intersection operation which is the one of the most important operations in various applications such as collision detection and ray tracing.

  9. Accelerated Life Test Plans for Repairable Systems With Multiple Independent Risks

    Microsoft Academic Search

    Xiao Liu; Long-Ching Tang

    2010-01-01

    This paper proposes a Bayesian approach to planning an accelerated life test (ALT) for repairable systems with multiple s-independent failure modes. A power law process (PLP), that combines both proportional intensity (PI) and acceleration time (AT) approaches, is used for modeling the failure process of repairable systems under ALT. Based on the Bayesian D-optimality, and Ds-optimality, we develop optimal plans

  10. Accelerated aging test results for aerospace wire insulation constructions

    Microsoft Academic Search

    William G. Dunbar

    1995-01-01

    Several wire insulation constructions were evaluated with and without continuous glow discharges at low pressure and high temperature to determine the aging characteristics of acceptable wire insulation constructions. It was known at the beginning of the test program that insulation aging takes several years when operated at normal ambient temperature and pressure of 20 C and 760 torr. Likewise, it

  11. Accelerated performance testing of concrete pavement with short slabs

    Microsoft Academic Search

    Jeffery R. Roesler; Victor G. Cervantes; Armen N. Amirkhanian

    2011-01-01

    A new concept for designing concrete pavements by optimising the slab geometry in order to reduce the slab thickness as well as to minimise the mechanical load transfer devices has recently been proposed. Theoretically, the reduced slab size lowers the load and curling-induced tensile stresses and concomitantly a thinner concrete slab can be constructed. Full-scale test sections were constructed and

  12. Concept, implementation and commissioning of the automation system for the accelerator module test facility AMTF

    SciTech Connect

    Böckmann, Torsten A.; Korth, Olaf; Clausen, Matthias; Schoeneburg, Bernd [MKS, Deutsches Elektronen Synchrotron DESY, 22607 Hamburg (Germany)

    2014-01-29

    The European XFEL project launched on June 5, 2007 will require about 103 accelerator modules as a main part of the XFEL linear accelerator. All superconducting components constituting the accelerator module like cavities and magnets have to be tested before the assembly. For the tests of the individual cavities and the complete modules an XFEL Accelerator Module Test Facility (AMTF) has been erected at DESY. The process control system EPICS (Experimental Physics and Industrial Control System) is used to control and operate the cryogenic plant and all its subcomponents. A complementary component of EPICS is the Open Source software suit CSS (Control System Studio). CSS is an integrated engineering, maintenance and operating tool for EPICS. CSS enables local and remote operating and monitoring of the complete system and thus represents the human machine interface. More than 250 PROFIBUS nodes work at the accelerator module test facility. DESY installed an extensive diagnostic and condition monitoring system. With these diagnostic tools it is possible to examine the correct installation and configuration of all PROFIBUS nodes in real time. The condition monitoring system based on FDT/DTM technology shows the state of the PROFIBUS devices at a glance. This information can be used for preventive maintenance which is mandatory for continuous operation of the AMTF facility. The poster will describe all steps form engineering to implementation and commissioning.

  13. Accelerated Wear Tests on Common Floor-covering Materials. 

    E-print Network

    Stewart, B. R.; Kunze, O. R.; Hobgood, Price.

    1958-01-01

    materials indicated there are variations in the changes of appearance and wear in these materials. Solid sheet vinyls and rubber tiles showed significantly less wear than asphalt tiles, vinyl- asbestos tiles, linoleums and cork. Asphalt tiles showed... in home installations. Six common floor covering materials-solid .sheet vinyls, rubber tiles, vinyl-asbestos tiles, J linoleums, corks and asphalt tiles-were used to construct 63 test specimens 2 x 2 feet in size. 1 T'ariations in specimens were...

  14. Accelerated Life Tests for Weibull Series Systems With Masked Data

    Microsoft Academic Search

    Tsai-Hung Fan; Wan-Lun Wang

    2011-01-01

    This article introduces a -stage step-stress acceler- ated life test on system products, where each system contains -independent non-identical components connected in series, and it fails if any component has broken down. Due to cost considera- tions or environmental restrictions, masked causes of system fail- ures and type-I censored observations might occur in the collected data. The time to failure

  15. Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?

    PubMed

    Nichols, Peter W B; White, Richard; Lucke, Terry

    2015-04-01

    Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18 mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300 ?m). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. PMID:25618819

  16. Globular Clusters as a Test for Gravity in the Weak Acceleration Regime

    NASA Astrophysics Data System (ADS)

    Scarpa, Riccardo; Marconi, Gianni; Gilmozzi, Roberto

    2006-03-01

    Non-baryonic Dark Matter (DM) appears in galaxies and other cosmic structures when and only when the acceleration of gravity, as computed considering only baryons, goes below a well defined value a0 = 1.2 × 10-8 cm s-2. This fact is extremely important and suggestive of the possibility of a breakdown of Newton's law of gravity (or inertia) below a0. It is therefore important to verify whether Newton's law of gravity holds in this regime of accelerations. In order to do this, one has to study the dynamics of objects that do not contain significant amounts of DM and therefore should follow Newton's prediction for whatever small accelerations. Globular clusters are believed, even by strong supporters of DM, to contain negligible amounts of DM and therefore are ideal for testing Newtonian dynamics in the low acceleration limit. Here, we discuss the status of an ongoing program aimed to do this test. Compared to other studies of globular clsuters, the novelty is that we trace the velocity dispersion profile of globular clusters far enough from the center to probe gravitational accelerations well below a0. In all three clusters studied so far the velocity dispersion is found to remain constant at large radii rather than follow the Keplerian falloff. On average, the flattening occurs at the radius where the cluster internal acceleration of gravity is 1.8 +/- 0.4 × 10-8 cm s-2, fully consistent with MOND predictions.

  17. Measurement of wakefields generated in accelerator test structures using the SLC

    SciTech Connect

    Adolphsen, C.; Bane, K.; Loew, G.; Ruth, R.; Thompson, K.; Wang, J.

    1992-10-01

    Research is underway at SLAC to develop accelerator structures for the next generation linear collider. An important feature of the design is a detuning of the dipole modes of the cells to suppress the long-range transverse wakefield by two orders of magnitude. This paper describes a facility, called ASSET, that will be incorporated into the SLAC Linear Collider (SLC) to test the long-range wakefield suppression and also to measure the other components of the wakefields generated in accelerator test structures.

  18. High-Power Tests of X-Band Dielectric-Loaded Accelerating Structures

    NASA Astrophysics Data System (ADS)

    Gold, Steven H.; Kinkead, Allen K.; Gai, Wei; Konecny, Richard; Jing, Chunguang; Liu, Wanming; Power, John G.; Yusof, Zikri M.

    2003-12-01

    Dielectric-loaded accelerating structures offer the potential of a simple, inexpensive alternative to copper disk-loaded structures for use in high-gradient rf linear accelerators. However, a variety of potential problems must be studied in order to demonstrate this potential, including rf breakdown, joule heating, and gas desorption. A joint Argonne National Laboratory — Naval Research Laboratory program is under way to investigate these issues, using high-power 11.424-GHz radiation from the NRL Magnicon Facility. Recent tests using a copper accelerating tube with an alumina liner have shown no evidence of rf breakdown at up to 5 MW drive power (equivalent to 8 MV/m accelerating gradient). However, substantial absorption of the incident microwave radiation was observed, accompanied by visible light emission from the dielectric surface, indicating the presence of electron multipactor in the tube.

  19. An accelerated exposure and testing apparatus for building joint sealants

    NASA Astrophysics Data System (ADS)

    White, C. C.; Hunston, D. L.; Tan, K. T.; Hettenhouser, J.; Garver, J. D.

    2013-09-01

    The design, fabrication, and implementation of a computer-controlled exposure and testing apparatus for building joint sealants are described in this paper. This apparatus is unique in its ability to independently control and monitor temperature, relative humidity, ultraviolet (UV) radiation, and mechanical deformation. Each of these environmental factors can be controlled precisely over a wide range of conditions during periods of a month or more. Moreover, as controlled mechanical deformations can be generated, in situ mechanical characterization tests can be performed without removing specimens from the chamber. Temperature and humidity were controlled during our experiments via a precision temperature regulator and proportional mixing of dry and moisture-saturated air; while highly uniform UV radiation was attained by attaching the chamber to an integrating sphere-based radiation source. A computer-controlled stepper motor and a transmission system were used to provide precise movement control. The reliability and effectiveness of the apparatus were demonstrated on a model sealant material. The results clearly show that this apparatus provides an excellent platform to study the long-term durability of building joint sealants.

  20. Experimental Testing of a Micron-Scale Laser-Powered Accelerator

    SciTech Connect

    Travish, G.; Arab, E.; Lacroix, U. H.; Rosenzweig, J. B.; Vartanian, N. [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Yoder, R. B. [Manhattanville College, Department of Physics, Purchase, NY 10577 (United States)

    2009-01-22

    An experimental program to develop, perfect, and demonstrate a micron-scale dielectric-based slab-symmetric accelerator is underway at UCLA. The effort includes parallel development of a particle source to be integrated with the accelerator, forming a monolithic radiation source. We present results from first-round cold tests of the structure resonance on a simplified metal-walled device, containing >100 structure periods in an area of 100x20 {mu}m. The resonance frequency and strength can be observed via reflection and transmission measurements on the drive laser. Initial measurements may be consistent with simulation. We also report on the status of the electron source development and on work toward an acceleration test in an all-dielectric structure.

  1. Design and test results of the Low Energy Demonstration Accelerator (LEDA) RF systems

    SciTech Connect

    Rees, D.; Bradley, J. III; Cummings, K.; Lynch, M.; Regan, A.; Rohlev, T.; Roybal, W.; Wang, Y.M.

    1998-12-01

    The Low Energy Demonstration Accelerator (LEDA) being constructed at Los Alamos will serve as the prototype for the low energy section of the Accelerator Production of Tritium (APT) accelerator. The APT accelerator requires over 200 RF systems each with a continuous wave output power of 1 MW. The reliability and availability of these RF systems is critical to the successful operation of the APT plant and prototypes of these systems are being developed and demonstrated on LEDA. The RF system design for LEDA includes three, 1.2 MW, 350 MHz continuous wave (CW), RF systems driving a radio frequency quadrupole (RFQ) and one, 1.0 MW, CW, RF system driving a coupled-cavity drift tube linac (CCDTL). This paper presents the design and test results for these RF systems including the klystrons, cathode power supply, circulators, RF vacuum windows, accelerator field and resonance control system, and RF transmission components. The three RF systems driving the RFQ use the accelerating structure as a power combiner, and this places some unique requirements on the RF system. These requirements and corresponding operational implications will be discussed.

  2. Lessons from two field tests on pipeline damage detection using acceleration measurement (Invited Paper)

    E-print Network

    Shinozuka, Masanobu

    Lessons from two field tests on pipeline damage detection using acceleration measurement (Invited, Irvine, CA USA 92697-2700 ABSTRACT Early detection of pipeline damages has been highlighted in water supply industry. Water pressure change in pipeline due to a sudden rupture causes pipe to vibrate

  3. DEVELOPMENT OF A HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN NATIONAL LABORATORY*

    E-print Network

    McDonald, Kirk

    954 DEVELOPMENT OF A HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN, New York 11973 and K. McDonald Princeton [Jniversity Abstract An electron gun utilizing a radio). Here we report on the de;$n of the electron gun which will provide r.f. bunches of up to 10 electrons

  4. PRODUCING AND MEASURING SMALL ELECTRON BUNCHES * Brookhaven Accelerator Test Facility, National Synchrotron Light Source

    E-print Network

    Brookhaven National Laboratory

    PRODUCING AND MEASURING SMALL ELECTRON BUNCHES * X.J. Wang Brookhaven Accelerator Test Facility measurement. The analysis of the kilo-Ampere 10 fs electron beam generation at the ATF will be presented . 1, such as the electron bunches, and measuring its bunch distribution. These difficult subjects, the status of producing

  5. Results of metallographical diagnostic examination of Navy half-watt thermoelectric converters degraded by accelerated tests

    NASA Technical Reports Server (NTRS)

    Rosell, F. E., Jr.; Rouklove, P. G.

    1977-01-01

    To verify the 15-year reliability of the Navy half-watt radioisotope thermoelectric generator (RTG), bismuth-telluride thermoelectric converters were submitted to testing at high temperatures which accelerated the degradation and caused failure of the converters. Metallographic diagnostic examination of failed units verified failure mechanisms. Results of diagnostic examinations are presented.

  6. Rapid identification and antimicrobial susceptibility testing reduce antibiotic use and accelerate pathogen-directed antibiotic use

    Microsoft Academic Search

    J. J. Kerremans; P. Verboom; Th. Stijnen; L. Hakkaart-van Roijen; W. H. F. Goessens; H. A. Verbrugh; A. Voss

    2008-01-01

    Introduction: Rapid bacterial identification and susceptibility tests can lead to earlier microbiological diagnosis and pathogen-directed, appropriate therapy. We studied whether accelerated diagnostics affected antibiotic use and patient outcomes. Patients and methods: A prospective randomized clinical trial was performed over a 2-year period. Inpatients were selected on the basis of a positive culture from normally sterile body fluids and randomly assigned

  7. An electrochemical method for accelerated testing of chloride diffusivity in concrete

    Microsoft Academic Search

    T. Zhang; O. E. Gjoerv

    1994-01-01

    In the present paper an electrochemical method for accelerated testing of chloride diffusivity in concrete is presented. The method is based on a theoretical relationship between chloride diffusivity and observed steady-state rate of chloride migration through the concrete. The concentration of the chloride source solution has a significant influence on the rate of chloride migration and, therefore, a correction factor

  8. Accelerator testing of the general antiparticle spectrometer; a novel approach to indirect dark matter detection

    Microsoft Academic Search

    C. J. Hailey; T. Aramaki; W. W. Craig; L. Fabris; F. Gahbauer; J. E. Koglin; N. Madden; K. Mori; H. T. Yu; K. P. Ziock

    2006-01-01

    We report on recent accelerator testing of a prototype general antiparticle spectrometer (GAPS). GAPS uses a novel approach for indirect dark matter searches that exploits the antideuterons produced in neutralino neutralino annihilations. GAPS captures these antideuterons into a target with the subsequent formation of exotic atoms. These exotic atoms decay with the emission of x-rays of precisely defined energy and

  9. Accelerated Life Testing Model for a Generalized Birnbaum-Saunders Distribution

    E-print Network

    Boyer, Edmond

    Accelerated Life Testing Model for a Generalized Birnbaum-Saunders Distribution Yao Cheng and E. A modeled by Birnbaum-Saunders (B-S) and Weibull distributions. Sometimes, materials with high cycle fatigue of this paper is to investigate a general Birnbaum-Saunders (GB-S) distribution which covers diverse hazard

  10. Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings.

    PubMed

    Shen, Jie; Burgess, Diane J

    2012-01-17

    Dexamethasone loaded poly(lactic-co-glycolic acid) (PLGA) microsphere/PVA hydrogel composites have been investigated as an outer drug-eluting coating for implantable devices such as glucose sensors to counter negative tissue responses to implants. The objective of this study was to develop a discriminatory, accelerated in vitro release testing method for this drug-eluting coating using United States Pharmacopeia (USP) apparatus 4. Polymer degradation and drug release kinetics were investigated under "real-time" and accelerated conditions (i.e. extreme pH, hydro-alcoholic solutions and elevated temperatures). Compared to "real-time" conditions, the initial burst and lag phases were similar using hydro-alcoholic solutions and extreme pH conditions, while the secondary apparent zero-order release phase was slightly accelerated. Elevated temperatures resulted in a significant acceleration of dexamethasone release. The accelerated release data were able to predict "real-time" release when applying the Arrhenius equation. Microsphere batches with faster and slower release profiles were investigated under "real-time" and elevated temperature (60°C) conditions to determine the discriminatory ability of the method. The results demonstrated both the feasibility and the discriminatory ability of this USP apparatus 4 method for in vitro release testing of drug loaded PLGA microsphere/PVA hydrogel composites. This method may be appropriate for similar drug/device combination products and drug delivery systems. PMID:22016033

  11. Progress in development of an accelerated leach test for low-level radioactive waste forms

    SciTech Connect

    Fuhrmann, M.; Pietrzak, R.; Dougherty, D.; Colombo, P.

    1987-08-01

    Factors that accelerate leaching from solidified low-level radioactive waste are being investigated to develop a short-term leach test that can be used to predict long-term releases. Data from work with portland cement containing radioactive tracers indicate that elevated temperatures can accelerate leaching of Ce-137 by at least a factor of eleven without changing the leaching mechanism. An 18 day leach test at 50/sup 0/C provided the equivalent of 200 days data taken at 20/sup 0/C. Portland cement containing 5 wt % Na/sub 2/SO/sub 4/ also can be accelerated, but to a lesser degree. Solid phase analysis indicated that pore plugging and increased tortuosity may be the cause of the smaller acceleration. Reduced specimen size was also a useful acceleration factor with inhomogeneities not being a problem in very small specimens. Elevated pH and 100 ppM EDTA in leaching solutions increased Sr-85 releases without altering Cs-137 leaching. 9 refs., 10 figs., 1 tab.

  12. Optimal bivariate step-stress accelerated life test for Type-I hybrid censored data

    Microsoft Academic Search

    Li Ling; Wei Xu; Minghai Li

    2011-01-01

    This paper presents a step-stress accelerated life test for two stress variables to obtain optimal hold times under a Type-I hybrid censoring scheme. An exponentially distributed life and a cumulative exposure model are assumed. The maximum-likelihood estimates are given, from which the asymptotic variance and the Fisher information matrix are obtained. The optimal test plan is determined for each combination

  13. Accelerated aging tests on magnet wires under high frequency pulsating voltage and high temperature

    Microsoft Academic Search

    S. Grzybowski; E. A. Feilat; P. Knight

    1999-01-01

    Breakdown voltage and accelerated multistress aging tests were conducted on fine gauge magnet wire of heavy build insulation film of polyurethane resin with nylon overcoat. The aging tests were carried out under simultaneous high frequency pulsating voltages (15-40 kHz) and high temperatures (100-180°C). The effects of the duty cycle and rise time of the voltage pulse on the time-to-breakdown were

  14. The first picosecond terawatt CO{sub 2} laser at the Brookhaven Accelerator Test Facility

    SciTech Connect

    Pogorelsky, I.V.; Ben-Zvi, I.; Babzien, M. [and others

    1998-02-01

    The first terawatt picosecond CO{sub 2} laser will be brought to operation at the Brookhaven Accelerator Test Facility in 1998. System consists of a single-mode TEA oscillator, picosecond semiconductor optical switch, multi-atmosphere. The authors report on design, simulation, and performance tests of the 10 atm final amplifier that allows for direct multi-joule energy extraction in a picosecond laser pulse.

  15. Status and specifications of a Project X front-end accelerator test facility at Fermilab

    SciTech Connect

    Steimel, J.; Webber, R.; Madrak, R.; Wildman, D.; Pasquinelli, R.; Evans-Peoples, E.; /Fermilab

    2011-03-01

    This paper describes the construction and operational status of an accelerator test facility for Project X. The purpose of this facility is for Project X component development activities that benefit from beam tests and any development activities that require 325 MHz or 650 MHz RF power. It presently includes an H- beam line, a 325 MHz superconducting cavity test facility, a 325 MHz (pulsed) RF power source, and a 650 MHz (CW) RF power source. The paper also discusses some specific Project X components that will be tested in the facility. Fermilab's future involves new facilities to advance the intensity frontier. In the early 2000's, the vision was a pulsed, superconducting, 8 GeV linac capable of injecting directly into the Fermilab Main Injector. Prototyping the front-end of such a machine started in 2005 under a program named the High Intensity Neutrino Source (HINS). While the HINS test facility was being constructed, the concept of a new, more versatile accelerator for the intensity frontier, now called Project X, was forming. This accelerator comprises a 3 GeV CW superconducting linac with an associated experimental program, followed by a pulsed 8 GeV superconducting linac to feed the Main Injector synchrotron. The CW Project X design is now the model for Fermilab's future intensity frontier program. Although CW operation is incompatible with the original HINS front-end design, the installation remains useful for development and testing many Project X components.

  16. Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations

    SciTech Connect

    Mao, X.S.; Leitner, M.Santana; Vollaire, J.

    2011-08-22

    Facility for Advanced Accelerator Experimental Tests (FACET) in SLAC will be used to study plasma wakefield acceleration. FLUKA Monte Carlo code was used to design a maze wall to separate FACET project and LCLS project to allow persons working in FACET side during LCLS operation. Also FLUKA Monte Carlo code was used to design the shielding for FACET dump to get optimum design for shielding both prompt and residual doses, as well as reducing environmental impact. FACET will be an experimental facility that provides short, intense pulses of electrons and positrons to excite plasma wakefields and study a variety of critical issues associated with plasma wakefield acceleration [1]. This paper describes the FACET beam parameters, the lay-out and its radiological issues.

  17. Identifying the failure mechanism in accelerated life tests by two-parameter lognormal distributions

    NASA Astrophysics Data System (ADS)

    Chunsheng, Guo; Yanfeng, Zhang; Ning, Wan; Hui, Zhu; Shiwei, Feng

    2014-08-01

    The failure mechanism stimulated by accelerated stress in the degradation may be different from that under normal conditions, which would lead to invalid accelerated life tests. To solve the problem, we study the relation between the Arrhenius equation and the lognormal distribution in the degradation process. Two relationships of the lognormal distribution parameters must be satisfied in the conclusion of the unaltered failure mechanism, the first is that the logarithmic standard deviations must be equivalent at different temperature levels, and the second is that the ratio of the differences between logarithmic means must be equal to the ratio of the differences between reciprocals of temperature. The logarithm of distribution lines must simultaneously have the same slope and regular interval lines. We studied the degradation of thick-film resistors in MCM by accelerated stress at four temperature levels (390, 400, 410 and 420 K), and the result agreed well with our method.

  18. Initial measurements of beam breakup instability in the advanced test accelerator

    SciTech Connect

    Chong, Y.P.; Caporaso, G.J.; Struve, K.W.

    1985-05-13

    This paper reports the measurements of beam breakup (BBU) instability performed on the Advanced Test Accelerator (ATA) up to the end of February, 1984. The main objective was to produce a high current usable electron beam at the ATA output. A well-known instability is BBU which arises from the accelerator cavity modes interacting with the electron beam. The dominant mode is TM/sub 130/ at a frequency of approximately 785 MHz. It couples most strongly to the beam motion and has been observed to grow in the Experimental Test Accelerator (ETA) which has only eight accelerator cavities. ATA has one hundred and seventy cavities and, therefore, the growth of BBU is expected to be more severe. In this paper, BBU measurements are reported for ATA with beam currents of 4 to 7 kA. Analysis showed that the growth of the instability with propagation distance was as expected for the lower currents. However, the high-current data showed an apparent higher growth rate than expected. An explanation for this anomaly is given in terms of a ''corkscrew'' excitation. The injector BBU noise level for a field emission brush cathode was found to be an order of magnitude lower than for a cold plasma discharge cathode. These injector rf amplitudes agree very well with values obtained using the method of differenced B sub solar loops.

  19. Rapid estimation of lives of deficient superpave mixes and laboratory-based accelerated mix testing models

    NASA Astrophysics Data System (ADS)

    Manandhar, Chandra Bahadur

    The engineers from the Kansas Department of Transportation (KDOT) often have to decide whether or not to accept non-conforming Superpave mixtures during construction. The first part of this study focused on estimating lives of deficient Superpave pavements incorporating nonconforming Superpave mixtures. These criteria were based on the Hamburg Wheel-Tracking Device (HWTD) test results and analysis. The second part of this study focused on developing accelerated mix testing models to considerably reduce test duration. To accomplish the first objective, nine fine-graded Superpave mixes of 12.5-mm nominal maximum aggregate size (NMAS) with asphalt grade PG 64-22 from six administrative districts of KDOT were selected. Specimens were prepared at three different target air void levels Ndesign gyrations and four target simulated in-place density levels with the Superpave gyratory compactor. Average number of wheel passes to 20-mm rut depth, creep slope, stripping slope, and stripping inflection point in HWTD tests were recorded and then used in the statistical analysis. Results showed that, in general, higher simulated in-place density up to a certain limit of 91% to 93%, results in a higher number of wheel passes until 20-mm rut depth in HWTD tests. A Superpave mixture with very low air voids Ndesign (2%) level performed very poorly in the HWTD test. HWTD tests were also performed on six 12.5-mm NMAS mixtures with air voids Ndesign of 4% for six projects, simulated in-place density of 93%, two temperature levels and five load levels with binder grades of PG 64-22, PG 64-28, and PG 70-22. Field cores of 150-mm in diameter from three projects in three KDOT districts with 12.5-mm NMAS and asphalt grade of PG 64-22 were also obtained and tested in HWTD for model evaluation. HWTD test results indicated as expected. Statistical analysis was performed and accelerated mix testing models were developed to determine the effect of increased temperature and load on the duration of the HWTD test. Good consistency between predicted and observed test results was obtained when higher temperature and standard load level were used. Test duration of the HWTD can thus be reduced to two hours or less using accelerated mix testing (statistical) models.

  20. Repeatable electrical measurement instrumentation for use in the accelerated stress testing of thin film solar cells

    NASA Technical Reports Server (NTRS)

    Davis, C. W.; Lathrop, J. W.

    1985-01-01

    Attention is given to the construction, calibration, and performance of a repeatable measurement system for use in conjunction with the accelerated stress testing of a-Si:H cells. A filtered diode array is utilized to approximate the spectral response of any type of solar cell in discrete portions of the spectrum. It is noted that in order to achieve the necessary degree of overall repeatability, it is necessary to pay particular attention to methods of contacting and positioning the cells.

  1. Comparison of Accelerated Testing with Modeling to Predict Lifetime of CPV Solder Layers (Presentation)

    SciTech Connect

    Silverman, T. J.; Bosco, N.; Kurtz, S.

    2012-03-01

    Concentrating photovoltaic (CPV) cell assemblies can fail due to thermomechanical fatigue in the die-attach layer. In this presentation, we show the latest results from our computational model of thermomechanical fatigue. The model is used to estimate the relative lifetime of cell assemblies exposed to various temperature histories consistent with service and with accelerated testing. We also present early results from thermal cycling experiments designed to help validate the computational model.

  2. Relativistic Klystron Two-Beam Accelerator studies at the RTA test facility

    SciTech Connect

    Westenskow, G.A.; Houck, T.L. [Lawrence Livermore National Lab., CA (United States); Anderson, D. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1996-08-16

    A prototype rf power source based on the Relativistic Klystron Two- Beam Accelerator (RK-TBA) concept is being constructed at LBNL to study physics, engineering, and costing issues. The prototype, called RTA, is described and compared to a full scale design appropriate for driving the Next Linear Collider. Specific details of the induction core test and pulsed power system are presented. Details of the 1-MeV, 1.2-kA induction gun currently under construction are described.

  3. A Comparison of Accelerated Aging Test Protocols for Cellular Foam Insulation

    Microsoft Academic Search

    Therese K. Stovall; Barbara A. Fabian; Gary E. Nelson; David R. Beatty

    Both the ASTM Standard Test Method for Estimating the Long-Term Change in the Thermal Resistance of Unfaced Rigid Closed-Cell Plastic Foams by Slicing and Scaling Under Controlled Laboratory Conditions (C 1303) and the Standard for Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams (CAN\\/ULC-S 770 ) are based on accelerating the foam aging process by slicing the foam

  4. Accelerated radiation damage testing of x-ray mask membrane materials

    Microsoft Academic Search

    Philip A. Seese; Kevin D. Cummings; Douglas J. Resnick; Arnold W. Yanof; William A. Johnson; Gregory M. Wells; John P. Wallace

    1993-01-01

    An accelerated test method and resulting metrology data are presented to show the effects of x- ray radiation on various x-ray mask membrane materials. A focused x-ray beam effectively reduces the radiation time to 1\\/5 of that required by normal exposure beam flux. Absolute image displacement results determined by this method indicate imperceptible movement for boron-doped silicon and silicon carbide

  5. Ferrographic Analysis of Wear Debris Generated in Accelerated Rolling Element Fatigue Tests

    Microsoft Academic Search

    William R. Jones. Jr; Richard J. Parker

    1979-01-01

    Ferrographic analysis was used to determine the types and quantities of wear particles generated during accelerated rolling contact fatigue tests. The NASA five-ball rolling contact fatigue tester was used. Ball specimens were made of AMS 5749, a corrosion resistant, high-temperature bearing steel. The lubricant was a super-refined naphthenic mineral oil. Conditions included a maximum Hertz stress of 5.52 × 10

  6. Wake potentials and impedances for the ATA (Advanced Test Accelerator) induction cell

    SciTech Connect

    Craig, G.D.

    1990-09-04

    The AMOS Wakefield Code is used to calculate the impedances of the induction cell used in the Advanced Test Accelerator (ATA) at Livermore. We present the wakefields and impedances for multipoles m = 0, 1 and 2. The ATA cell is calculated to have a maximum transverse impedance of approximately 1000 {Omega}/m at 875 MHz with a quality factor Q = 5. The sensitivity of the impedance spectra to modeling variations is discussed.

  7. The Heavy Vehicle Simulator in Accelerated Pavement Testing - a Historical Overview and New Developments

    Microsoft Academic Search

    N. F. Coetzee; N. Burmas; J. T. Harvey; C. L. Monismith

    The purpose of this paper is twofold. Firstly, it w ill provide a brief description of the technological developments involved in the Heavy Vehicle Simulator (HVS) accelerated pavement testing equipment. This covers the period from its conception in the late 1960's, to the current state-of-the art HVS Mk-IV +, the HVS-A Mk-V, as well as the new HVS Mk VI.

  8. Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Shastry, Rohit; Pinero, Luis; Peterson, Todd; Mathers, Alex

    2012-01-01

    NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

  9. Feasibility study of a nonequilibrium MHD accelerator concept for hypersonic propulsion ground testing

    SciTech Connect

    Lee, Ying-Ming; Simmons, G.A.; Nelson, G.L. [MSE Inc., Butte, MT (United States)

    1995-12-31

    A National Aeronautics and Space Administration (NASA) funded research study to evaluate the feasibility of using magnetohydrodynamic (MHD) body force accelerators to produce true air simulation for hypersonic propulsion ground testing is discussed in this paper. Testing over the airbreathing portion of a transatmospheric vehicle (TAV) hypersonic flight regime will require high quality air simulation for actual flight conditions behind a bow shock wave (forebody, pre-inlet region) for flight velocities up to Mach 16 and perhaps beyond. Material limits and chemical dissociation at high temperature limit the simulated flight Mach numbers in conventional facilities to less than Mach 12 for continuous and semi-continuous testing and less than Mach 7 for applications requiring true air chemistry. By adding kinetic energy directly to the flow, MHD accelerators avoid the high temperatures and pressures required in the reservoir region of conventional expansion facilities, allowing MHD to produce true flight conditions in flight regimes impossible with conventional facilities. The present study is intended to resolve some of the critical technical issues related to the operation of MHD at high pressure. Funding has been provided only for the first phase of a three to four year feasibility study that would culminate in the demonstration of MHD acceleration under conditions required to produce true flight conditions behind a bow shock wave to flight Mach numbers of 16 or greater. MHD critical issues and a program plan to resolve these are discussed.

  10. Development of a Dielectric-Loaded Accelerator Test Facility Based on an X-Band Magnicon Amplifier

    NASA Astrophysics Data System (ADS)

    Gold, S. H.; Kinkead, A. K.; Gai, W.; Power, J. G.; Konecny, R.; Jing, C.; Tantawi, S. G.; Nantista, C. D.; Hu, Y.; Du, X.; Tang, C.; Lin, Y.; Bruce, R. W.; Bruce, R. L.; Fliflet, A. W.; Lewis, D.

    2006-01-01

    The Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), are developing a dielectric-loaded accelerator (DLA) test facility powered by the 11.424-GHz magnicon amplifier that was developed jointly by NRL and Omega-P, Inc. Thus far, DLA structures developed by ANL have been tested at the NRL Magnicon Facility without injected electrons, including tests of alumina and magnesium calcium titanate structures at gradients up to ˜8 MV/m. The next step is to inject electrons in order to build a compact DLA test accelerator. The Accelerator Laboratory of Tsinghua University in Beijing, China has developed a 5-MeV electron injector for the accelerator, and SLAC is developing a means to combine the two magnicon output arms, and to drive the injector and an accelerator section with separate control of the power ratio and relative phase. Also, RWBruce Associates, working with NRL, is developing a means to join ceramic tubes to produce long accelerating sections using a microwave brazing process. The installation and commissioning of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year.

  11. An electrochemical method for accelerated testing of chloride diffusivity in concrete

    SciTech Connect

    Zhang, T.; Gjoerv, O.E. (Norwegian Inst. of Tech., Trondheim (Norway). Div. of Building Materials)

    1994-01-01

    In the present paper an electrochemical method for accelerated testing of chloride diffusivity in concrete is presented. The method is based on a theoretical relationship between chloride diffusivity and observed steady-state rate of chloride migration through the concrete. The concentration of the chloride source solution has a significant influence on the rate of chloride migration and, therefore, a correction factor for ionic interaction in the relationship is introduced. It is shown that the relationship can be used for calculation of chloride diffusivity under various testing conditions. Some experimental results are also presented.

  12. Comparison of test particle acceleration in torsional spine and fan reconnection regimes

    NASA Astrophysics Data System (ADS)

    Hosseinpour, M.; Mehdizade, M.; Mohammadi, M. A.

    2014-10-01

    Magnetic reconnection is a common phenomenon taking place in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. Torsional spine and fan reconnections are important mechanisms proposed for steady-state three-dimensional null-point reconnection. By using the magnetic and electric fields for these regimes, we numerically investigate the features of test particle acceleration in both regimes with input parameters for the solar corona. By comparison, torsional spine reconnection is found to be more efficient than torsional fan reconnection in an acceleration of a proton to a high kinetic energy. A proton can gain as high as 100 MeV of relativistic kinetic energy within only a few milliseconds. Moreover, in torsional spine reconnection, an accelerated particle can escape either along the spine axis or on the fan plane depending on its injection position. However, in torsional fan reconnection, the particle is only allowed to accelerate along the spine axis. In addition, in both regimes, the particle's trajectory and final kinetic energy depend on the injection position but adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory.

  13. Comparison of test particle acceleration in torsional spine and fan reconnection regimes

    SciTech Connect

    Hosseinpour, M., E-mail: hosseinpour@tabrizu.ac.ir; Mehdizade, M.; Mohammadi, M. A. [Plasma Physics Department, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2014-10-15

    Magnetic reconnection is a common phenomenon taking place in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. Torsional spine and fan reconnections are important mechanisms proposed for steady-state three-dimensional null-point reconnection. By using the magnetic and electric fields for these regimes, we numerically investigate the features of test particle acceleration in both regimes with input parameters for the solar corona. By comparison, torsional spine reconnection is found to be more efficient than torsional fan reconnection in an acceleration of a proton to a high kinetic energy. A proton can gain as high as 100?MeV of relativistic kinetic energy within only a few milliseconds. Moreover, in torsional spine reconnection, an accelerated particle can escape either along the spine axis or on the fan plane depending on its injection position. However, in torsional fan reconnection, the particle is only allowed to accelerate along the spine axis. In addition, in both regimes, the particle's trajectory and final kinetic energy depend on the injection position but adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory.

  14. Accelerated life tests on a new water tree retardant insulation for power cables

    SciTech Connect

    Sarma, H. [AT Plastics Inc., Brampton, Ontario (Canada)] [AT Plastics Inc., Brampton, Ontario (Canada)

    1997-04-01

    This paper describes the results of an investigation in which 15 kV rated cables insulated with a new water tree retardant cross-linked polyethylene (TR XLPE) were subjected to accelerated aging tests under a controlled voltage stress and thermal load cycle conditions. Cables insulated with conventional XLPE and a commercially available TR XLPE were used as reference test populations to affirm the test methodology. Under the chosen conditions, cable life of the new TR XLPE as calculated using Weibull and log normal statistical distributions, was more than twice that for the reference TRXLPE. Extensive diagnostic measurements (water content, dissipation factor, water tree analysis) were performed on failed cable samples to bring out the differences between the three insulations. Electron micrographic investigations revealed the size and distribution of micro voids in the new TR XLPE to be smaller supporting its extended life under these tests. The experimental details of the accelerated life tests are also documented in a clear manner facilitating any archival of the data for future analysis and comparison.

  15. NEUTRON MONITOR DATA ON THE 15 JUNE 1991 FLARE: NEUTRONS AS A TEST FOR PROTON ACCELERATION SCENARIO

    E-print Network

    Usoskin, Ilya G.

    NEUTRON MONITOR DATA ON THE 15 JUNE 1991 FLARE: NEUTRONS AS A TEST FOR PROTON ACCELERATION SCENARIO.J.TANSKANEN University of Oulu, SF-90570, Oulu, Finland ABSTRACT. Response of A1ma-Ata neuuon monitor for solar neutrons of proton acceleration during the flare. The analysis of neutron monitor is an evidence in favour

  16. A Proposal for a TESLA Accelerator Module Test Facility W.D.Moeller, B.Petersen, B.Sparr

    E-print Network

    1 A Proposal for a TESLA Accelerator Module Test Facility W.D.Moeller, B.Petersen, B.Sparr Deutsches Elektronen Synchrotron TESLA Report No. 2001-08 Abstract The Tera-eV Energy Superconducting Linear Accelerator (TESLA), a 32 km long superconducting linear electron/positron collider of 500 GeV (upgradeable

  17. Accelerated life test of sputtering and anode deposit spalling in a small mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Power, J. L.

    1975-01-01

    Tantalum and molybdenum sputtered from discharge chamber components during operation of a 5 centimeter diameter mercury ion thruster adhered much more strongly to coarsely grit blasted anode surfaces than to standard surfaces. Spalling of the sputtered coating did occur from a coarse screen anode surface but only in flakes less than a mesh unit long. The results were obtained in a 200 hour accelerated life test conducted at an elevated discharge potential of 64.6 volts. The test approximately reproduced the major sputter erosion and deposition effects that occur under normal operation but at approximately 75 times the normal rate. No discharge chamber component suffered sufficient erosion in the test to threaten its structural integrity or further serviceability. The test indicated that the use of tantalum-surfaced discharge chamber components in conjunction with a fine wire screen anode surface should cure the problems of sputter erosion and sputtered deposits spalling in long term operation of small mercury ion thrusters.

  18. Methodology to improve design of accelerated life tests in civil engineering projects.

    PubMed

    Lin, Jing; Yuan, Yongbo; Zhou, Jilai; Gao, Jie

    2014-01-01

    For reliability testing an Energy Expansion Tree (EET) and a companion Energy Function Model (EFM) are proposed and described in this paper. Different from conventional approaches, the EET provides a more comprehensive and objective way to systematically identify external energy factors affecting reliability. The EFM introduces energy loss into a traditional Function Model to identify internal energy sources affecting reliability. The combination creates a sound way to enumerate the energies to which a system may be exposed during its lifetime. We input these energies into planning an accelerated life test, a Multi Environment Over Stress Test. The test objective is to discover weak links and interactions among the system and the energies to which it is exposed, and design them out. As an example, the methods are applied to the pipe in subsea pipeline. However, they can be widely used in other civil engineering industries as well. The proposed method is compared with current methods. PMID:25111800

  19. Beam Based HOM Analysis of Accelerating Structures at the TESLA Test Facility Linac

    SciTech Connect

    Wendt, M.; Schreiber, S.; Castro, P.; Gossel, A.; /DESY; Huning, M.; /Fermilab; Devanz, G.; Jablonka, M.; Magne, C.; Napoly, O.; /Saclay; Baboi, N.; /SLAC

    2005-08-09

    The beam emittance in future linear accelerators for high energy physics and SASE-FEL applications depends highly on the field performance in the accelerating structures, i.e. the damping of higher order modes (HOM). Besides theoretical and laboratory analysis, a beam based analysis technique was established [1] at the TESLA Test Facility (TTF) linac. It uses a charge modulated beam of variable modulation frequency to excite dipole modes. This causes a modulation of the transverse beam displacement, which is observed at a downstream BPM and associated with a direct analysis of the modes at the HOM-couplers. A brief introduction of eigenmodes of a resonator and the concept of the wake potential is given. Emphasis is put on beam instrumentation and signal analysis aspects, required for this beam based HOM measurement technique.

  20. Preliminary results from pressure tank test and field acceleration test of New-Profiling float of Japan (NINJA)

    NASA Astrophysics Data System (ADS)

    Izawa, K.; Ando, K.; Mizuno, K.; Inoue, A.; Shikama, N.; Takeuchi, K.; Sekimoto, M.

    2002-12-01

    As one of contributions of Japan to the international Argo community, one of Japanese ocean instrument manufacturers, Tsurumi Seiki Co. (TSK), has started the development of original profiling float in 2000. We purchased the four TSK floats in 2001, and performed the pressure tank test and the acceleration field test in the north Pacific. Among four floats, two are carrying SBE41 CTD sensor, and two are carrying TSK-original CTD sensor. In the pressure tank test, by controlling a tank pressure as float controller expects, we created the ideal ocean in a tank for the float. The TSK float successfully worked as was scheduled, and measured profile data when the float was coming up to the surface (i.e. pressure in tank was decreasing). We also performed the ballasting test of weight of the TSK float to drift at 2000dbars (Swift and Riser, 1994). After these tests, we launched two floats with TSK sensor in the north Pacific in June. One of the floats has finished the 20th profile on 26 August 2002 and is still working. The technical message from the float indicates the stable parking near 2000dbars, the stable profiling speed, and no missing profile data. The temperature and salinity data also indicate the stable T-S relations in deeper layer below 1500dbars among profiles. In this presentation, we will also show the results of field test of the floats with SBE sensor, which will be launched in October 2002.

  1. Feasibility of Using Neural Network Models to Accelerate the Testing of Mechanical Systems

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1998-01-01

    Verification testing is an important aspect of the design process for mechanical mechanisms, and full-scale, full-length life testing is typically used to qualify any new component for use in space. However, as the required life specification is increased, full-length life tests become more costly and lengthen the development time. At the NASA Lewis Research Center, we theorized that neural network systems may be able to model the operation of a mechanical device. If so, the resulting neural network models could simulate long-term mechanical testing with data from a short-term test. This combination of computer modeling and short-term mechanical testing could then be used to verify the reliability of mechanical systems, thereby eliminating the costs associated with long-term testing. Neural network models could also enable designers to predict the performance of mechanisms at the conceptual design stage by entering the critical parameters as input and running the model to predict performance. The purpose of this study was to assess the potential of using neural networks to predict the performance and life of mechanical systems. To do this, we generated a neural network system to model wear obtained from three accelerated testing devices: 1) A pin-on-disk tribometer; 2) A line-contact rub-shoe tribometer; 3) A four-ball tribometer.

  2. In Situ, Time-Resolved Accelerator Grid Erosion Measurements in the NSTAR 8000 Hour Ion Engine Wear Test

    NASA Technical Reports Server (NTRS)

    Sovey, J.

    1997-01-01

    Time-resolved, in situ measurements of the charge exchange ion erosion pattern on the downstream face of the accelerator grid have been made during an ongoin wear test of the NSTAR 30 cm ion thruster.

  3. European Particle Accelerator Conference -Rome, Italy -June 7-12, 1988 DEVELOPMENT OFA HIGH BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT

    E-print Network

    McDonald, Kirk

    BRIGHTNESS ELECTRON GUN FOR THE ACCELERATOR TEST FACILITY AT BROOKHAVEN NATIONAL LABORATORY* K. Batchelor, HDonald Princeton University At innBNL--41767 DE89 002179 Abstract An electron gun utilizing aradio frequency on the design of (he electron gun which will provide r.f. bunches of upto 101 electrons synchronized

  4. Accelerated Testing of Epoxy-FRP Composites for Civil Infrastructure Applications: Property Changes and Mechanisms of Degradation

    Microsoft Academic Search

    Andrew Stewart; Elliot P. Douglas

    2012-01-01

    Accelerated testing of FRP systems is frequently performed due to the long service life of these materials used to repair damaged civil structures. This testing typically involves exposure to common environmental conditions seen in the field. However, the main limitation of these experiments is that the testing protocols typically do not consider a change in the failure mechanism as a

  5. Using globular clusters to test gravity in the weak acceleration regime: NGC 6171

    NASA Astrophysics Data System (ADS)

    Scarpa, Riccardo; Marconi, Gianni; Gilmozzi, Roberto

    2004-12-01

    As part of an ongoing program to test Newton’s law of gravity in the low acceleration regime using globular clusters, we present here new results obtained for NGC 6171. Combining VLT spectra for 107 stars with data from the literature, we were able to trace the velocity dispersion profile up to 16 pc from the cluster center, probing accelerations of gravity down to 3.5x10-9 cm s-2 . The velocity dispersion is found to remain constant at large radii (with an asymptotic values of 2.7 km s-1 ) rather than follow the Keplerian falloff. Similar results were previously found for the globular clusters ? Centauri and M15. We have now studied three clusters and all three have been found to have a flat dispersion profile beyond the radius where their internal acceleration of gravity is a0 1.2x10-8 cm s-2 . Whether this indicates a failure of Newtonian dynamics or some more conventional dynamical effect (e.g., tidal heating) is still unclear. However, the similarities emerging between globular clusters and elliptical galaxies seem to favor the first of the two possibilities.

  6. ACCELERATED TESTING OF NEUTRON-ABSORBING ALLOYS FOR NUCLEAR CRITICALITY CONTROL

    SciTech Connect

    Ronald E. Mizia

    2011-10-01

    The US Department of Energy requires nuclear criticality control materials be used for storage of highly enriched spent nuclear fuel used in government programs and the storage of commercial spent nuclear fuel at the proposed High-Level Nuclear Waste Geological Repository located at Yucca Mountain, Nevada. Two different metallic alloys (Ni-Cr-Mo-Gd and borated stainless steel) have been chosen for this service. An accelerated corrosion test program to validate these materials for this application is described and a performance comparison is made.

  7. Simulation and steering in the intertank matching section of the ground test accelerator

    SciTech Connect

    Yuan, V.W.; Bolme, G.O.; Johnson, K.F.; Mottershead, C.T.; Sander, O.R.; Smith, M.T. [Los Alamos National Lab., NM (United States); Erickson, J.L. [Grumman Energy Systems Division, Bethpage, NY (United States)

    1994-10-01

    The Intertank Matching Section (IMS) of the Ground Test Accelerator (GTA) is a short (36 cm) beamline designed to match the Radio Frequency Quadrupole (RFQ) exit beam into the first Drift Tube LINAC (DTL) tank. The IMS contains two steering quadrupoles (SMQs) and four variable-field focussing quads (VFQs). The SMQs are fixed strength permanent magnet quadrupoles on mechanical actuators capable of transverse movement for the purpose of steering the beam. The upstream and downstream steering quadrupoles are labelled SMQ1 and SMQ4 respectively. Also contained in the IMS are two RF cavities for longitudinal matching.

  8. Upgrade of the A0 photoinjector laser system for NML accelerator test facility at Fermilab

    SciTech Connect

    Ruan, J.; Edwards, H.; Fliller, R.P., III; Santucci, J.K.; /Fermilab

    2007-06-01

    The current Fermilab A0 Photoinjector laser system includes a seed laser, a flashlamp pumped multipass amplifier cavity, a flashlamp pumped 2-pass amplifier system followed by an Infra-Red (IR) to Ultra-Violet (UV) conversion stage. However the current system can only deliver up to 800 pulses due to the low efficiency of Nd:Glass used inside multi-pass cavity. In this paper we will report the effort to develop a new multi pass cavity based on Nd:YLF crystal end-pumped by diode laser. We will also discuss the foreseen design of the laser system for the NML accelerator test facility at Fermilab.

  9. Development and beam test of a continuous wave radio frequency quadrupole accelerator

    NASA Astrophysics Data System (ADS)

    Ostroumov, P. N.; Mustapha, B.; Barcikowski, A.; Dickerson, C.; Kolomiets, A. A.; Kondrashev, S. A.; Luo, Y.; Paskvan, D.; Perry, A.; Schrage, D.; Sharamentov, S. I.; Sommer, R.; Toter, W.; Zinkann, G.

    2012-11-01

    The front end of any modern ion accelerator includes a radio frequency quadrupole (RFQ). While many pulsed ion linacs successfully operate RFQs, several ion accelerators worldwide have significant difficulties operating continuous wave (CW) RFQs to design specifications. In this paper we describe the development and results of the beam commissioning of a CW RFQ designed and built for the National User Facility: Argonne Tandem Linac Accelerator System (ATLAS). Several innovative ideas were implemented in this CW RFQ. By selecting a multisegment split-coaxial structure, we reached moderate transverse dimensions for a 60.625-MHz resonator and provided a highly stabilized electromagnetic field distribution. The accelerating section of the RFQ occupies approximately 50% of the total length and is based on a trapezoidal vane tip modulation that increased the resonator shunt impedance by 60% in this section as compared to conventional sinusoidal modulation. To form an axially symmetric beam exiting the RFQ, a very short output radial matcher with a length of 0.75?? was developed. The RFQ is designed as a 100% oxygen-free electronic (OFE) copper structure and fabricated with a two-step furnace brazing process. The radio frequency (rf) measurements show excellent rf properties for the resonator, with a measured intrinsic Q equal to 94% of the simulated value for OFE copper. An O5+ ion beam extracted from an electron cyclotron resonance ion source was used for the RFQ commissioning. In off-line beam testing, we found excellent coincidence of the measured beam parameters with the results of beam dynamics simulations performed using the beam dynamics code TRACK, which was developed at Argonne. These results demonstrate the great success of the RFQ design and fabrication technology developed here, which can be applied to future CW RFQs.

  10. Accelerated gravity testing of aquitard core permeability and implications at formation and regional scale

    NASA Astrophysics Data System (ADS)

    Timms, W. A.; Crane, R.; Anderson, D. J.; Bouzalakos, S.; Whelan, M.; McGeeney, D.; Rahman, P. F.; Guinea, A.; Acworth, R. I.

    2015-03-01

    Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, the extraction of fuels from strata such as coal beds, and the confinement of waste within the earth. The current work demonstrates that relatively rapid and reliable hydraulic conductivity (K) measurement of aquitard cores using accelerated gravity can inform and constrain larger scale assessments of hydraulic connectivity. Steady state fluid velocity through a low K porous sample is linearly related to accelerated gravity (g-level) in a centrifuge permeameter (CP) unless consolidation or geochemical reactions occur. The CP module was custom designed to fit a standard 2 m diameter geotechnical centrifuge (550 g maximum) with a capacity for sample dimensions of 30 to 100 mm diameter and 30 to 200 mm in length, and a maximum total stress of ~2 MPa at the base of the core. Formation fluids were used as influent to limit any shrink-swell phenomena which may alter the permeability. Vertical hydraulic conductivity (Kv) results from CP testing of cores from three sites within the same regional clayey silt formation varied (10-7 to 10-9 m s-1, n = 14). Results at one of these sites (1.1 × 10-10 to 3.5 × 10-9 m s-1, n = 5) that were obtained in < 24 h were similar to in situ Kv values (3 × 10-9 m s-1) from pore pressure responses over several weeks within a 30 m clayey sequence. Core scale and in situ Kv results were compared with vertical connectivity within a regional flow model, and considered in the context of heterogeneity and preferential flow paths at site and formation scale. More reliable assessments of leakage and solute transport though aquitards over multi-decadal timescales can be achieved by accelerated core testing together with advanced geostatistical and numerical methods.

  11. Test Results of a Superconducting Quadrupole Model Designed for Linear Accelerator Applications

    SciTech Connect

    Kashikhin, Vladimir S.; Andreev, Nikolai; Chlachidze, Guram; DiMarco, Joseph; Kashikhin, Vadim V.; Lamm, Michael J.; Lopes, Mauricio L.; Orris, Darryl; Tartaglia, Michael; Tompkins, John C.; Velev, Gueorgui; /Fermilab

    2008-08-01

    The first model of a superconducting quadrupole for use in a Linear Accelerator was designed, built and tested at Fermilab. The quadrupole has a 78 mm aperture, and a cold mass length of 680 mm. A superferric magnet configuration with iron poles and four racetrack coils was chosen based on magnet performance, cost, and reliability considerations. Each coil is wound using enamel insulated, 0.5 mm diameter, NbTi superconductor. The quadrupole package also includes racetrack type dipole steering coils. The results of the quadrupole design, manufacturing and test, are presented. Specific issues related to the quadrupole magnetic center stability, superconductor magnetization and mechanical stability are discussed. The magnet quench performance and results of magnetic measurements will also be briefly discussed.

  12. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    SciTech Connect

    Krause, David L. [National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH 44135 (United States); Kantzos, Pete T. [Ohio Aerospace Institute, NASA Glenn Research Center, Cleveland, OH 44135 (United States)

    2006-01-20

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  13. Accelerated in vitro durability testing of nonvascular Nitinol stents based on the electrical potential sensing method

    NASA Astrophysics Data System (ADS)

    Park, Chan-Hee; Tijing, Leonard D.; Pant, Hem Raj; Kim, Tae-Hyung; Amarjargal, Altangerel; Kim, Han Joo; Kim, Cheol Sang

    2013-09-01

    In this paper, we report an evaluation of the performance of a new stent durability tester based on the electrical potential sensing method through accelerated in vitro testing of six different nonvascular Nitinol stents simulating physiological conditions. The stents were subjected to a pulsatile loading of 33 Hz for a total of 62,726,400 cycles, at constant temperature and pressure of 35±0.5 °C and 120±4 mmHg, respectively. The electrical potential of each stent was measured in real-time and monitored for any changes in readings. After conducting test-to-fracture tests, the stents were visually checked, and by scanning electron microscopy. A sudden electrical potential drop in the readings suggests a fracture has occurred, and the only two instances of fracture in our present results were correctly determined by our present device, with the fractures confirmed visually after the test. The excellent performance of our new method shows good potential for a highly reliable and applicable in vitro durability testing for different kinds and sizes of metallic stents.

  14. ASSESSMENT OF THE PCFBC-EXPOSED AND ACCELERATED LIFE-TESTED CANDLE FILTERS

    SciTech Connect

    M.A. Alvin

    1999-09-30

    Development of the hot gas filtration technology has been the focus of DOE/FETC and Siemens Westinghouse Power Corporation during the past twenty years. Systems development during this time has successfully lead to the generation and implementation of high temperature Siemens Westinghouse particulate filtration systems that are currently installed and are operational at Demonstration Plant sites, and which are ready for installation at commercial plant sites. Concurrently, materials development has advanced the use of commercially available oxide- and nonoxide-based monoliths, and has fostered the manufacture and use of second generation, oxide-based, continuous fiber reinforced ceramic composites and filament wound materials. This report summarizes the material characterization results for commercially available and second generation filter materials tested in Siemens Westinghouse's advanced, high temperature, particulate removal system at the Foster Wheeler, pressurized circulating fluidized-bed combustion, pilot-scale test facility in Karhula, Finland, and subsequent extended accelerated life testing of aged elements in Siemens Westinghouse pressurized fluidized-bed combustion simulator test facility in Pittsburgh, PA. The viability of operating candle filters successfully for over 1 year of service life has been shown in these efforts. Continued testing to demonstrate the feasibility of acquiring three years of service operation on aged filter elements is recommended.

  15. Temperature and current accelerated lifetime conditions and testing of laser diodes for ESA BepiColombo space mission

    NASA Astrophysics Data System (ADS)

    Klumel, Genady; Karni, Yoram; Cohen, Shalom; Rech, Markus; Weidlich, Kai

    2011-03-01

    System designers and end users of diode pumped solid state lasers often require knowledge of the operability limits of QCW laser diode pump sources and their predicted reliability performance as a function of operating conditions. Accelerated ageing at elevated temperatures, duty cycles and/or currents allows extended lifetime testing of diode stacks to be executed on compressed timescales with high confidence. We present a novel, time-efficient technique for the determination of accelerated lifetime test conditions using degradation rate data, rather than the traditionally used failures against time data. To assess the effect of thermally accelerated ageing, 4 groups of 4 stacks each were operated for 60 million pulses at different temperature stress levels by varying the pulse repetition rate from 100Hz to 250Hz. The measured power degradation rates fitted to an Arrhenius type model, result in activation energy of 0.47- 0.74eV, apparently indicating two thermally activated degradation modes with different activation energies. Similarly, for current accelerated ageing, another 4 groups of 4 stacks were tested at operation currents from 120A to 150A. The optical power degradation rates due to current stress follow a power law behavior with a current acceleration factor of 1.7. The obtained acceleration parameters allowed considerable reduction of the lifetime test duration, which would have otherwise taken an unacceptably long time under nominal operating conditions. The successful results of the accelerated lifetime have been a major milestone enabling qualification of SCD stacks as pump sources for the laser altimeter in ESA Bepi-Colombo space mission. The presented reliability analysis allows life test qualification programs to be accelerated for generic QCW stacks and their lifetime to be predicted in various operating environments.

  16. Fatigue-test acceleration with flight-by-flight loading and heating to simulate supersonic-transport operation

    NASA Technical Reports Server (NTRS)

    Imig, L. A.; Garrett, L. E.

    1973-01-01

    Possibilities for reducing fatigue-test time for supersonic-transport materials and structures were studied in tests with simulated flight-by-flight loading. In order to determine whether short-time tests were feasible, the results of accelerated tests (2 sec per flight) were compared with the results of real-time tests (96 min per flight). The effects of design mean stress, the stress range for ground-air-ground cycles, simulated thermal stress, the number of stress cycles in each flight, and salt corrosion were studied. The flight-by-flight stress sequences were applied to notched sheet specimens of Ti-8Al-1Mo-1V and Ti-6Al-4V titanium alloys. A linear cumulative-damage analysis accounted for large changes in stress range of the simulated flights but did not account for the differences between real-time and accelerated tests. The fatigue lives from accelerated tests were generally within a factor of two of the lives from real-time tests; thus, within the scope of the investigation, accelerated testing seems feasible.

  17. Columbus PMP Critical Technologies Program: Approach for materials life time prediction

    Microsoft Academic Search

    Heinrich Baumann; Fabienne Dricot

    1993-01-01

    An approach to resolve the verification of materials extended life time behavior for the Columbus elements is described. The combination of the 10 to 30 years life time requirement, on orbit maintenance and repair led to a new strategy in materials selection and verification. This strategy, introduced as the 'PMP (Parts, Materials and Processes) Critical Technologies Program' also considers the

  18. Expected life-time utility and hedging demands in a partially observable economy

    Microsoft Academic Search

    Frederik Lundtofte

    2008-01-01

    This paper analyzes the expected life-time utility and the hedging demands in an exchange only, representative agent general equilibrium under incomplete information. We derive an expression for the investor's expected life-time utility, and analyze his hedging demands for intertemporal changes in the stochastic unobservable growth of the endowment process and the changing quality of information regarding these changes. The hedging

  19. The Accelerated Reader Program's Relationship to Student Achievement on the English-Language Arts California Standards Test

    ERIC Educational Resources Information Center

    Rodriguez, Steve

    2007-01-01

    This study aimed to investigate the potential of the Accelerated Reader (AR) program to positively impact student scores on the English-Language Arts California Standards Test (CST). The degree of attention placed on student reading achievement and improvement in high-stakes student standardized test scores in the state of California, as well as…

  20. Accelerated hermeticity testing of a glasssilicon package formed by rapid thermal processing aluminum-to-silicon nitride bonding$

    E-print Network

    Lin, Liwei

    aluminum-to-silicon nitride bonding$ Mu Chiao* , Liwei Lin Department of Mechanical Engineering, Berkeley-to-silicon nitride bonding has been demonstrated and characterized by means of accelerated hermeticity testing the test. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Hermetic wafer bonding; Packaging

  1. Calculating Nozzle Side Loads using Acceleration Measurements of Test-Based Models

    NASA Technical Reports Server (NTRS)

    Brown, Andrew M.; Ruf, Joe

    2007-01-01

    As part of a NASA/MSFC research program to evaluate the effect of different nozzle contours on the well-known but poorly characterized "side load" phenomena, we attempt to back out the net force on a sub-scale nozzle during cold-flow testing using acceleration measurements. Because modeling the test facility dynamics is problematic, new techniques for creating a "pseudo-model" of the facility and nozzle directly from modal test results are applied. Extensive verification procedures were undertaken, resulting in a loading scale factor necessary for agreement between test and model based frequency response functions. Side loads are then obtained by applying a wide-band random load onto the system model, obtaining nozzle response PSD's, and iterating both the amplitude and frequency of the input until a good comparison of the response with the measured response PSD for a specific time point is obtained. The final calculated loading can be used to compare different nozzle profiles for assessment during rocket engine nozzle development and as a basis for accurate design of the nozzle and engine structure to withstand these loads. The techniques applied within this procedure have extensive applicability to timely and accurate characterization of all test fixtures used for modal test.A viewgraph presentation on a model-test based pseudo-model used to calculate side loads on rocket engine nozzles is included. The topics include: 1) Side Loads in Rocket Nozzles; 2) Present Side Loads Research at NASA/MSFC; 3) Structural Dynamic Model Generation; 4) Pseudo-Model Generation; 5) Implementation; 6) Calibration of Pseudo-Model Response; 7) Pseudo-Model Response Verification; 8) Inverse Force Determination; 9) Results; and 10) Recent Work.

  2. Cryogenic test facility of superconducting magnets for the accelerator complex NICA

    NASA Astrophysics Data System (ADS)

    Nikiforov, D.; Agapov, N.; Khodzhibagiyan, H.; Emelianov, N.; Korolev, V.

    2014-05-01

    The new accelerator complex NICA is being constructed on the basis of the existing superconducting synchrotron Nuclotron at JINR. NICA will consist of 3 rings of superconducting magnets: the Nuclotron, a booster synchrotron and a two-aperture collider ring. Superconducting dipole and quadrupole magnets for the NICA complex will be manufactured and tested at the new test facility. All the magnets contain a cold iron yoke and saddle-shaped superconducting windings made of the hollow NbTi composite superconducting cable refrigerated by two-phase helium flow at 4.5 K. The cryogenic system of the new facility is based on helium refrigerators with excess return flow. The scheme of the cryogenic testing area of the test facility is presented. A mathematical model of the cooling-down processes of the magnets was developed based on the experimental data for the prototypes of the booster and collider superconducting magnets. The calculated parameters allow us having a shorter time of cooling-down and warming-up of the magnets, thus reaching the necessary productivity of the facility.

  3. Corrosion characterization of durable silver coatings by electrochemical impedance spectroscopy and accelerated environmental testing.

    PubMed

    Chu, Chung-Tse; Fuqua, Peter D; Barrie, James D

    2006-03-01

    Highly reflective front-surface silver mirrors are needed for many optical applications. While various protective dielectric coating schemes have been developed, the long-term durability of Ag mirrors is still of great concern in the optics community for a variety of applications under harsh environments. The corrosion protection behavior of a SiNx-coated silver-mirror coating scheme was tested with electrochemical impedance spectroscopy (EIS) and accelerated environmental testing, including humidity and salt fog tests. The EIS data obtained were fitted with different equivalent circuit models. The results suggested that the 100A thick SiNx coating produced by rf magnetron sputtering was porous and acted as a leaky capacitor on the Ag film, whereas the addition of a NiCrNx interlayer as thin as 3A between SiNx and Ag films resulted in a much denser SiNx coating with a low-frequency impedance value of 2 orders of magnitude higher than that without the interlayer. Humidity and salt fog testing of different silver coatings showed similar results. The 100A SiNx/3A-NiCrNx/Ag coating exhibited excellent corrosion resistance against the corrosive environments used in this study. PMID:16539267

  4. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    SciTech Connect

    NONE

    1994-10-01

    This document is the third volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of appendices C through U of the report

  5. Final safety analysis report for the Ground Test Accelerator (GTA), Phase 2

    SciTech Connect

    NONE

    1994-10-01

    This document is the first volume of a 3 volume safety analysis report on the Ground Test Accelerator (GTA). The GTA program at the Los Alamos National Laboratory (LANL) is the major element of the national Neutral Particle Beam (NPB) program, which is supported by the Strategic Defense Initiative Office (SDIO). A principal goal of the national NPB program is to assess the feasibility of using hydrogen and deuterium neutral particle beams outside the Earth`s atmosphere. The main effort of the NPB program at Los Alamos concentrates on developing the GTA. The GTA is classified as a low-hazard facility, except for the cryogenic-cooling system, which is classified as a moderate-hazard facility. This volume consists of an introduction, summary/conclusion, site description and assessment, description of facility, and description of operation.

  6. 600 kV modulator design for the SLAC Next Linear Collider Test Accelerator

    SciTech Connect

    Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

    1992-07-01

    Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 {mu}s, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at {approx} 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 {mu}s pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz.

  7. Fast ion instability at the Cornell Electron Storage Ring Test Accelerator

    NASA Astrophysics Data System (ADS)

    Chatterjee, A.; Blaser, K.; Hartung, W.; Rubin, D.; Wang, S. T.

    2015-06-01

    Fast ion instability can lead to deterioration of an electron beam (increasing emittance and instability of a train of bunches) in storage rings and linacs. We study this at the Cornell electron storage ring test accelerator using a 2.1 GeV low emittance beam. As the source of ions is residual gas, our measurements are conducted at various pressures, including nominal vacuum as well as injected gas (Ar, Kr). We experiment with mitigation techniques, including changing the bunch pattern to have mini-trains instead of one long train, as well as increasing the initial vertical emittance of the beam. We also check to ensure that ion-trapping is not a substantial effect in our measurements. We measure turn-by-turn vertical bunch size and position, as well as the multibunch power spectrum. Our measurements confirm fast ion instability under all vacuum conditions. A detailed simulation is then used to compare theory with observations.

  8. Extremely low vertical-emittance beam in accelerator-test facility at KEK

    SciTech Connect

    Kubo, K.; Akemoto, M.; Anderson, S.; Aoki, T.; Araki, S.; Bane, K.L.F.; Blum, P.; Corlett, J.; Dobashi, K.; Emma, P.; Frisch, J.; Fukuda, M.; Guo, Z.; Hasegawa, K.; Hayano, H.; Higo, T.; Higurashi, A.; Honda, Y.; Iimura, T.; Imai, T.; Jobe, K.; Kamada, S.; Karataev, P.; Kashiwagi, S.; Kim, E.; Kobuki, T.; Kotseroglou, T.; Kurihara, Y.; Kuriki, M.; Kuroda, R.; Kuroda, S.; Lee, T.; Luo, X.; McCormick, D.J.; McKee, B.; Mimashi, T.; Minty, M.; Muto, T.; Naito, Takashi; Naumenko, G.; Nelson, J.; Nguyen, M.N.; Oide, K.; Okugi, T.; Omori, T.; Oshima, T.; Pei, G.; Potylitsyn, A.; Qin, Q.; Raubenheimer, T.; Ross, M.; Sakai, H.; Sakai, I.; Schmidt, F.; Slaton, T.; Smith, H.; Smith, S.; Suzuki, Toshikazu; Takano, M.; Takeda, Seishi; Terunuma, N.; Toge, N.; Turner, J.; Urakawa, J.; Vogel, V.; Woodley, M.; Yocky, J.; Young, A.; Zimmerman, F.; ATF Collaboration

    2002-05-13

    Electron beams with the lowest, normalized transverse emittance recorded so far were produced and confirmed in single-bunch-mode operation of the Accelerator Test Facility at KEK. We established a tuning method of the damping rings which achieves a small vertical dispersion and small x-y orbit coupling. The vertical emittance was less than 1 percent of the horizontal emittance. At the zero-intensity limit, the vertical normalized emittance was less than 2.8 x 10{sup -8} rad m at beam energy 1.3 GeV. At high intensity, strong effects of intrabeam scattering were observed, which had been expected in view of the extremely high particle density due to the small transverse emittance.

  9. On the Use of Accelerated Test Methods for Characterization of Advanced Composite Materials

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.

    2003-01-01

    A rational approach to the problem of accelerated testing for material characterization of advanced polymer matrix composites is discussed. The experimental and analytical methods provided should be viewed as a set of tools useful in the screening of material systems for long-term engineering properties in aerospace applications. Consideration is given to long-term exposure in extreme environments that include elevated temperature, reduced temperature, moisture, oxygen, and mechanical load. Analytical formulations useful for predictive models that are based on the principles of time-based superposition are presented. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for determining specific aging mechanisms.

  10. Development of a new test of accelerated long-term forgetting in epilepsy 

    E-print Network

    Williams, Katie

    2010-11-24

    Accelerated long-term forgetting (ALF) is a novel form of memory impairment in which epilepsy patients demonstrate intact recall and recognition after standard delays, but they show an accelerated rate of forgetting in comparison to controls when...

  11. The High-Frequency/Acceleration Head Heave Test in Detecting Otolith Diseases.

    PubMed

    Kessler, Paul; Tomlinson, David; Blakeman, Alan; Rutka, John; Ranalli, Paul; Wong, Agnes

    2007-10-01

    OBJECTIVE:: To investigate whether transient, high-acceleration interaural head heaves (translational vestibulo-ocular reflex [tVOR]) could aid in the diagnosis of otolith diseases. STUDY DESIGN:: Prospective cohort study. SETTING:: Tertiary referral center. PATIENTS:: Thirteen patients with symptoms suggestive of otolith diseases and 10 age-matched controls. INTERVENTIONS:: Patients underwent a clinical otoneurologic examination and standard laboratory audiovestibular evaluation, including audiometry, electronystagmography with bithermal caloric, Halmagyi-Curthoys head thrust test with search coils, and vestibular-evoked myogenic potential. All subjects underwent subjective visual vertical (SVV) and tVOR testings. MAIN OUTCOME MEASURES:: Sensitivity (ratio of peak eye to peak head velocities) and velocity gain (ratio of actual to ideal peak eye velocities). RESULTS:: Five of 13 patients showed no abnormality in any tests. Of the remaining 8, 3 (38%) had reduced tVOR responses, whereas 1 (13%) had abnormal SVV. Sensitivity and velocity gains were symmetrically reduced in 2 patients, who had symptoms for 8 and 24 months. A third patient, symptomatic for 7 weeks, had asymmetric reduction of tVOR responses and a deviated SVV. CONCLUSION:: Both head heave and SVV tests detect acute, asymmetric otolith diseases. Subjective visual vertical test relies on imbalance of utricular tone and may not detect bilateral symmetric diseases or partial diseases with central compensation. Our preliminary data in a small group of patients show that measuring the tVOR in a higher and more physiologic range of frequencies may serve as useful adjunct to detect acute and chronic otolith dysfunction and seems to be superior to the SVV in detecting bilateral symmetric or asymmetric otolith diseases. PMID:17704721

  12. Simulation prediction and experiment setup of vacuum laser acceleration at Brookhaven National Lab-Accelerator Test Facility

    NASA Astrophysics Data System (ADS)

    Shao, L.; Cline, D.; Ding, X.; Ho, Y. K.; Kong, Q.; Xu, J. J.; Pogorelsky, I.; Yakimenko, V.; Kusche, K.

    2013-02-01

    This paper presents the pre-experiment plan and prediction of the first stage of vacuum laser acceleration (VLA) collaborating by UCLA, Fudan University and ATF-BNL. This first stage experiment is a proof-of-principle to support our previously posted novel VLA theory. Simulations show that based on ATF's current experimental conditions the electron beam with initial energy of 15 MeV can get net energy gain from an intense CO2 laser beam. The difference in electron beam energy spread is observable by the ATF beam line diagnostics system. Further, this energy spread expansion effect increases along with an increase in laser intensity. The proposal has been approved by the ATF committee and the experiment will be our next project.

  13. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    SciTech Connect

    Wright, R.M.; Zander, M.E.; Brown, S.K.; Sandoval, D.P.; Gilpatrick, J.D.; Gibson, H.E.

    1992-01-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) will be discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. The current status of the system will be illustrated by samples of experimental data.

  14. Communication Life-times of long-lived coherences under different motional regimes

    E-print Network

    Communication Life-times of long-lived coherences under different motional regimes Aurélien Bornet a strong radio-frequency field, in the simplest case a continuous-wave (CW) radio-frequency (rf) field

  15. Life-time and hierarchy of memory in the dissipative quantum model of brain

    E-print Network

    Eleonora Alfinito; Giuseppe Vitiello

    1999-12-30

    Some recent developments of the dissipative quantum model of brain are reported. In particular, the time-dependent frequency case is considered with its implications on the different life-times of the collective modes.

  16. Life-time and hierarchy of memory in the dissipative quantum model of brain

    E-print Network

    Alfinito, E; Alfinito, Eleonora; Vitiello, Giuseppe

    1999-01-01

    Some recent developments of the dissipative quantum model of brain arereported. In particular, the time-dependent frequency case is considered withits implications on the different life-times of the collective modes.

  17. Columbus PMP Critical Technologies Program: Approach for materials life time prediction

    NASA Astrophysics Data System (ADS)

    Baumann, Heinrich; Dricot, Fabienne

    1993-06-01

    An approach to resolve the verification of materials extended life time behavior for the Columbus elements is described. The combination of the 10 to 30 years life time requirement, on orbit maintenance and repair led to a new strategy in materials selection and verification. This strategy, introduced as the 'PMP (Parts, Materials and Processes) Critical Technologies Program' also considers the schedule and funding constraints which require adaptation to the minimum program needs and pragmatic approaches.

  18. Temperature and current accelerated lifetime conditions and testing of laser diodes for ESA BepiColombo space mission

    Microsoft Academic Search

    Genady Klumel; Yoram Karni; Shalom Cohen; Markus Rech; Kai Weidlich

    2011-01-01

    System designers and end users of diode pumped solid state lasers often require knowledge of the operability limits of QCW laser diode pump sources and their predicted reliability performance as a function of operating conditions. Accelerated ageing at elevated temperatures, duty cycles and\\/or currents allows extended lifetime testing of diode stacks to be executed on compressed timescales with high confidence.

  19. Design of Bivariate Accelerated Life Tests with One Main Effect and One Interaction Effect for Log-Location-Scale Distributions

    Microsoft Academic Search

    Haiyan Xu; Heliang Fei; Zhenmin Chen

    2011-01-01

    One may think that the design of bivariate accelerated life tests (ALTs) with one main effect and one interaction effect can be extended directly from the design proposed by Escobar and Meeker (1995) for bivariate ALTs with no interaction between the two variables. However, it can be shown that the “split” method, which is used in pursuing bivariate ALTs designs

  20. Computational analyses on the effects of irregular conditions during accelerated thermal cycling tests on board level solder joint reliability

    Microsoft Academic Search

    Dennis Lau; S. W. Ricky Lee

    2004-01-01

    This study is intended to investigate the effects of irregular conditions on the board level solder joint reliability during accelerated thermal cycling tests. In a previous research, the thermal fatigue lives of PBGA solder joints have been estimated using a 2-dimensional finite element model. The computational results agreed very well with the experimental data. In the present study, with the

  1. Corrosion Embrittlement of Duralumin II Accelerated Corrosion Tests and the Behavior of High-Strength Aluminum Alloys of Different Compositions

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1928-01-01

    The permanence, with respect to corrosion, of light aluminum alloy sheets of the duralumin type, that is, heat-treatable alloys containing Cu, Mg, Mn, and Si is discussed. Alloys of this type are subject to surface corrosion and corrosion of the interior by intercrystalline paths. Results are given of accelerated corrosion tests, tensile tests, the effect on corrosion of various alloying elements and heat treatments, electrical resistance measurements, and X-ray examinations.

  2. CVD-diamond-based position-sensitive detector test with electron beam from a RhodotronTM accelerator

    Microsoft Academic Search

    Deming Shu; P. K. Job; T. M. Kuzay; S. Korenev

    2001-01-01

    A position-sensitive detector using insulating-type CVD diamond as its substrate material has been developed at the Advanced Photon Source (APS), Argonne National Laboratory, and was tested with a 5 MeV electron beam from a CW RhodotronTM accelerator at the STERIS Corporation. The preliminary test result shows that the free-standing insulating-type CVD-diamond acts as a solid-state ion chamber under the 5

  3. Tested by Fire - How two recent Wildfires affected Accelerator Operations at LANL

    SciTech Connect

    Spickermann, Thomas [Los Alamos National Laboratory

    2012-08-01

    In a little more than a decade two large wild fires threatened Los Alamos and impacted accelerator operations at LANL. In 2000 the Cerro Grande Fire destroyed hundreds of homes, as well as structures and equipment at the DARHT facility. The DARHT accelerators were safe in a fire-proof building. In 2011 the Las Conchas Fire burned about 630 square kilometers (250 square miles) and came dangerously close to Los Alamos/LANL. LANSCE accelerator operations Lessons Learned during Las Conchas fire: (1) Develop a plan to efficiently shut down the accelerator on short notice; (2) Establish clear lines of communication in emergency situations; and (3) Plan recovery and keep squirrels out.

  4. Measurement and compensation of horizontal crabbing at the Cornell Electron Storage Ring Test Accelerator

    NASA Astrophysics Data System (ADS)

    Ehrlichman, M. P.; Chatterjee, A.; Hartung, W.; Heltsley, B.; Peterson, D. P.; Rider, N.; Rubin, D.; Sagan, D.; Shanks, J. P.; Wang, S. T.

    2014-04-01

    In storage rings, horizontal dispersion in the rf cavities introduces horizontal-longitudinal (xz) coupling, contributing to beam tilt in the xz plane. This coupling can be characterized by a "crabbing" dispersion term ?a that appears in the normal mode decomposition of the 1-turn transfer matrix. ?a is proportional to the rf cavity voltage and the horizontal dispersion in the cavity. We report experiments at the Cornell Electron Storage Ring Test Accelerator where xz coupling was explored using three lattices with distinct crabbing properties. We characterize the xz coupling for each case by measuring the horizontal projection of the beam with a beam size monitor. The three lattice configurations correspond to (i) 16 mrad xz tilt at the beam size monitor source point, (ii) compensation of the ?a introduced by one of two pairs of rf cavities with the second, and (iii) zero dispersion in rf cavities, eliminating ?a entirely. Additionally, intrabeam scattering is evident in our measurements of beam size vs rf voltage.

  5. Cosmic opacity: cosmological-model-independent tests and their impacts on cosmic acceleration

    E-print Network

    Zhengxiang Li; Puxun Wu; Hongwei Yu; Zong-Hong Zhu

    2013-05-29

    With assumptions that the violation of the distance-duality (DD) relation entirely arises from non-conservation of the photon number and the absorption is frequency independent in the observed frequency range, we perform cosmological-model-independent tests for the cosmic opacity. The observational data include the largest Union2.1 SN Ia sample, which is taken for observed $D_\\mathrm{L}$, and galaxy cluster samples compiled by De Filippis {\\it et al.} and Bonamente {\\it et al.}, which are responsible for providing observed $D_\\mathrm{A}$. Two parameterizations, $\\tau(z)=2\\epsilon z$ and $\\tau(z)=(1+z)^{2\\epsilon}-1$ are adopted for the optical depth associated to the cosmic absorption. We find that, an almost transparent universe is favored by Filippis {\\it et al.} sample but it is only marginally accommodated by Bonomente {\\it et al.} samples at 95.4% confidence level (C. L.) (even at 99.7% C. L. when the $rtests into consideration, we correct the distance modulus of SNe Ia and then use them to study their cosmological implications. The constraints on the $\\Lambda$CDM show that a decelerating expanding universe with $\\Omega_\\Lambda=0$ is only allowed at 99.7% C. L. by observations when the Bonamente {\\it et al.} sample is considered. Therefore, our analysis suggests that an accelerated cosmic expansion is still needed to account for the dimming of SNe and the standard cosmological scenario remains to be supported by current observations.

  6. X-ray beam size measurements on the Advanced Test Accelerator

    SciTech Connect

    Struve, K.W.; Chambers, F.W.; Lauer, E.J.; Slaughter, D.R.

    1986-01-01

    The electron beam size has been determined on the Advanced Test Accelerator (ATA) by intercepting the beam with a target and measuring the resulting x-ray intensity as a function of time as the target is moved through the beam. Several types of targets have been used. One is a tantalum rod which extends completely across the drift chamber. Another is a tungsten powder filled carbon crucible. Both of these probes are moved from shot to shot so that the x-ray signal intensity varies with probe position. A third is a larger tantalum disk which is inserted on beam axis to allow determining beam size on a one shot basis. The x-ray signals are detected with an MCP photomultiplier tube located at 90/sup 0/ to the beamline. It is sufficiently shielded to reject background x-rays and neutrons. The signals were digitized, recorded and later unfolded to produce plots of x-ray intensity versus probe position for several times during the pulse. The presumption that the x-ray intensity is proportional to beam current density is checked computationally. Details of the probe construction and PMT shielding, as well as sample measurements are given.

  7. Big Bang nucleosynthesis: Accelerator tests and can. cap omega. /sub B/ really be large

    SciTech Connect

    Schramm, D.N.

    1987-10-01

    The first collider tests of cosmological theory are now underway. The number of neutrino families in nature, N/sub nu/, plays a key role in elementary particle physics as well as in the synthesis of the light elements during the early evolution of the Universe. Standard Big Bang Nucleosynthesis argues for N/sub nu/ = 3 +- 1. Current limits on N/sub nu/ from the CERN anti pp collider and e/sup +/e/sup -/ colliders are presented and compared to the cosmological bound. Supernova SN 1987A is also shown to give a limit on N/sub nu/ comparable to current accelerator bounds. All numbers are found to be small thus verifying the Big Bang model at an earlier epoch than is possible by traditional astronomical observations. Future measurements at SLC and LEP will further tighten this argument. Another key prediction of the standard Big Bang Nucleosynthesis is that the baryon density must be small (..cap omega../sub B/ less than or equal to 0.1). Recent attempts to try to subvert this argument using homogeneities of various types are shown to run afoul of the /sup 7/Li abundance which has now become a rather firm constraint. 18 refs., 2 figs.

  8. Integration Testing of a Modular Discharge Supply for NASA's High Voltage Hall Accelerator Thruster

    NASA Technical Reports Server (NTRS)

    Pinero, Luis R.; Kamhawi, hani; Drummond, Geoff

    2010-01-01

    NASA s In-Space Propulsion Technology Program is developing a high performance Hall thruster that can fulfill the needs of future Discovery-class missions. The result of this effort is the High Voltage Hall Accelerator thruster that can operate over a power range from 0.3 to 3.5 kW and a specific impulse from 1,000 to 2,800 sec, and process 300 kg of xenon propellant. Simultaneously, a 4.0 kW discharge power supply comprised of two parallel modules was developed. These power modules use an innovative three-phase resonant topology that can efficiently supply full power to the thruster at an output voltage range of 200 to 700 V at an input voltage range of 80 to 160 V. Efficiencies as high as 95.9 percent were measured during an integration test with the NASA103M.XL thruster. The accuracy of the master/slave current sharing circuit and various thruster ignition techniques were evaluated.

  9. Laboratory testing of Ultra High Performance Concrete deck joints for use in accelerated bridge construction

    Microsoft Academic Search

    Douglas Robert Hartwell

    2011-01-01

    Accelerated bridge construction is one rapid renewal technique being investigated to address the needs of the United States' aging infrastructure under the Second Strategic Highway Research Program (SHRP 2). SHRP 2 Project R04 aimed to develop standards and codes for accelerated bridge construction through the construction of a demonstration bridge. Several design details were important the rapid renewal aspect of

  10. The LeRC rail accelerators: Test designs and diagnostic techniques

    NASA Technical Reports Server (NTRS)

    Zana, L. M.; Kerslake, W. R.; Sturman, J. C.; Wang, S. Y.; Terdan, F. F.

    1983-01-01

    The feasibility of using rail accelerators for various in-space and to-space propulsion applications was investigated. A 1 meter, 24 sq mm bore accelerator was designed with the goal of demonstrating projectile velocities of 15 km/sec using a peak current of 200 kA. A second rail accelerator, 1 meter long with a 156.25 sq mm bore, was designed with clear polycarbonate sidewalls to permit visual observation of the plasma arc. A study of available diagnostic techniques and their application to the rail accelerator is presented. Specific topics of discussion include the use of interferometry and spectroscopy to examine the plasma armature as well as the use of optical sensors to measure rail displacement during acceleration. Standard diagnostics such as current and voltage measurements are also discussed.

  11. Polarization Losses under Accelerated Stress Test Using Multiwalled Carbon Nanotube Supported Pt Catalyst in PEM Fuel Cells

    SciTech Connect

    Park, Seh K.; Shao, Yuyan; Kou, Rong; Viswanathan, Vilayanur V.; Towne, Silas A.; Rieke, Peter C.; Liu, Jun; Lin, Yuehe; Wang, Yong

    2011-03-01

    The electrochemical behavior for Pt catalysts supported on multiwalled carbon nanotubes and Vulcan XC-72 in proton exchange membrane fuel cells under accelerated stress test was examined by cyclic voltammetry, electrochemical impedance spectroscopy, and polarization technique. Pt catalyst supported on multiwalled carbon nanotubes exhibited highly stable electrochemical surface area, oxygen reduction kinetics, and fuel cell performance at a highly oxidizing condition, indicating multiwalled carbon nanotubes show high corrosion resistance and strong interaction with Pt nanoparticles. The Tafel slope, ohmic resistances, and limiting current density determined were used to differentiate kinetic, ohmic, mass-transfer polarization losses from the actual polarization curve. Kinetic contribution to the total overpotential was larger throughout the stress test. However, the fraction of kinetic overpotential decreased and mass-transfer overpotential portion remained quite constant during accelerated stress test, whereas the fraction of ohmic overpotential primarily originating from severe proton transport limitation in the catalyst layer increased under the anodic potential hold.

  12. Evaluation of oxidative behavior of polyolefin geosynthetics utilizing accelerated aging tests based on temperature and pressure

    NASA Astrophysics Data System (ADS)

    Li, Mengjia

    Polyolefin geosynthetics are susceptible to oxidation, which eventually leads to the reduction in their engineering properties. In the application of polyolefin geosynthetics, a major issue is an estimate of the materials durability (i.e. service lifetime) under various aging conditions. Antioxidant packages are added to the polyolefin products to extend the induction time, during which antioxidants are gradually depleted and polymer oxidation reactions are prevented. In this PhD study, an improved laboratory accelerating aging method under elevated and high pressure environments was applied to evaluate the combined effect of temperature and pressure on the depletion of the antioxidants and the oxidation of polymers. Four types of commercial polyolefn geosynthetic materials selected for aging tests included HDPE geogrid, polypropylene woven and nonwoven geotextiles. A total of 33 different temperature/pressure aging conditions were used, with the incubation duration up to 24 months. The applied oven temperature ranged from 35°C to 105°C and the partial oxygen pressure ranged from 0.005 MPa to 6.3 MPa. Using the Oxidative Induction Time (OIT) test, the antioxidant depletion, which is correlated to the decrease of the OIT value, was found to follow apparent first-order decay. The OIT data also showed that, the antioxidant depletion rate increased with temperature according to the Arrhenius equation, while under constant temperatures, the rate increased exponentially with the partial pressure of oxygen. A modified Arrhenius model was developed to fit the antioxidant depletion rate as a function of temperature and pressure and to predict the antioxidant lifetime under various field conditions. This study has developed new temperature/pressure incubation aging test method with lifetime prediction models. Using this new technique, the antioxidant lifetime prediction results are close to regular temperature aging data while the aging duration can be reduced considerably. Using the enhanced aging pressure and temperature with this aging method plus a new analytical methodology utilizing time-temperature-superposition and time-pressure-superposition techniques, the post-antioxidant lifetime (Stage C) of the materials can also be predicted and so a total lifetime for different polyolefin geosynthetics can be evaluated quantitatively.

  13. Status of the visible Free-Electron Laser at the Brookhaven Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fisher, A.S.; Friedman, A.; Gallardo, J.; Ingold, G.; Kirk, H.; Kramer, S.; Lin, L.; Rogers, J.T.; Sheehan, J.F.; van Steenbergen, A.; Woodle, M.; Xie, J.; Yu, L.H.; Zhang, R. (Brookhaven National Lab., Upton, NY (United States)); Bhowmik, A. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.)

    1991-01-01

    The 500 nm Free-Electron Laser (ATF) of the Brookhaven National Laboratory is reviewed. We present an overview of the ATF, a high-brightness, 50-MeV, electron accelerator and laser complex which is a users' facility for accelerator and beam physics. A number of laser acceleration and FEL experiments are under construction at the ATF. The visible FEL experiment is based on a novel superferric 8.8 mm period undulator. The electron beam parameters, the undulator, the optical resonator, optical and electron beam diagnostics are discussed. The operational status of the experiment is presented. 22 refs., 7 figs.

  14. Lead-bismuth spallation target design of the accelerator-driven test facility (ADTF).

    SciTech Connect

    Gohar, Y.; Finck, P.; Hanson, A.; Herceg, J.; Koploy, M.; Krajtl, L.; Mijatovic, P.; Pointer, W. D.; Saiveau, J.; Sofu, T.; Todosow, M.

    2002-05-06

    A design methodology for the lead-bismuth eutectic (LBE) spallation target has been developed and applied for the accelerator-driven test facility (ADTF) target. This methodology includes the target interface with the subcritical multiplier (SCM) of the ADTF and the different engineering aspects of the target design, physics, heat-transfer, hydraulics, structural, radiological, and safety analyses. Several design constrains were defined and utilized for the target design process to satisfy different engineering requirements and to minimize the time and the cost of the design development. Interface requirements with the subcritical multiplier were defined based on target performance parameters and material damage issues to enhance the lifetime of the target structure. Different structural materials were considered to define the most promising candidate based on the current database including radiation effects. The developed target design has a coaxial geometrical configuration to minimize the target footprint and it is installed vertically along the SCM axis. LBE is the target material and the target coolant with ferritic steel (HT-9 alloy) structural material. The proton beam has 8.33-mA current uniformly distributed and 8.14-cm beam radius resulting in a current density of 40 {micro}A/cm{sup 2}. The beam power is 5 MW and the proton energy is 600 MeV. The beam tube has 10-cm radius to accommodate the halo current. A hemi-spherical geometry is used for the target window, which is connected to the beam tube. The beam tube is enclosed inside two coaxial tubes to provide inlet and outlet manifolds for the LBE coolant. The inlet and the outlet coolant manifolds and the proton beam are entered from the top above the SCM. The paper describes the design criteria, engineering constraints, and the developed target design for the ADTF.

  15. Testing prototypes of high-temperature superconducting current leads of cryogenic stand for testing magnetic elements of the NICA accelerating complex

    NASA Astrophysics Data System (ADS)

    Kres, E. V.; Kadenko, I. N.; Bessheiko, O. A.; Belov, D. V.; Blinov, N. A.; Galimov, A. R.; Zorin, A. G.; Karpinsky, V. N.; Nikiforov, D. N.; Pivin, R. V.; Smirnov, A. V.; Shevchenko, E. V.; Smirnov, S. A.; Khodzhibagiyan, G. G.; Liu, Cheng Lian

    2014-09-01

    In the Laboratory of High Energies at the Joint Institute for Nuclear Research, as part of the NICA-MPD [1] project, tests of two prototypes of HTSC current leads prepared at ASIPP institute (Hefei, China) have been performed [2, 3] to measure electric and heat parameters and to search for structural and physical drawbacks. Based on the experimental results, necessary changes are made in the structure of HTSC current leads of the testing stand for the magnetic element testing of the NICA accelerating complex and its basic setups: the Nuclotron, Booster, and Collider.

  16. Testing of a loop heat pipe experimental apparatus under varied acceleration

    E-print Network

    Kurwitz, Richard Cable

    1997-01-01

    gravitational acceleration and microgravity was completed with satisfactory prediction. The use of experimentally validated predictions will allow designers to use LHP's in space systems with higher confidence in expected performance....

  17. Motor current signature analysis during accelerated life testing of form wound induction motors

    Microsoft Academic Search

    Prabhakar Neti; Manoj R. Shah; Karim Younsi; John Krahn; Joe Yingneng Zhou; C. David Whitefield

    2010-01-01

    The work presented in this paper describes motor accelerated thermo-mechanical aging and helps set the stage for on-line monitoring\\/data analysis as an effective means to detect a fault as electrical machine develops it and identify its type in real time. As a first step towards this goal, Motor Current Signature Analysis (MCSA) is applied to the data collected during accelerated

  18. Endoscopic tissue fluorescence life-time imaging by frequency doamin light-induced fluorescence

    NASA Astrophysics Data System (ADS)

    Mizeret, Jerome C.; Wagnieres, Georges A.; Studzinski, A.; Shangguan, C.; van den Bergh, Hubert

    1995-12-01

    An instrumentation is being developed to draw a fluorescence life-time map of tissue endoscopically. This fluorescence life-time of an endogenous or exogenous fluorochrome gives information about the physico-chemical environment which is thought to vary between normal and diseased tissue. The excitation light from a cw laser is modulated in amplitude at high frequencies by an electro-optic modulator and delivered to the endoscopic site through an optical fiber. The image of the tissue is spectrally split in two parts, the one being the backscattered excitation light, the other the fluorescence of the fluorochromes. Each image is focused on the photocathode of an image intensifier whose gain is modulated at the same frequency. By acquiring frames at different phases between the excitation and the emission, it is possible to calculate pixel by pixel the apparent fluorescence life-time of the corresponding tissue region.

  19. Study of cement-epoxy interfaces, accelerated testing, and surface modification

    NASA Astrophysics Data System (ADS)

    Stewart, Andrew

    Adhesion between concrete and fiber reinforced polymer (FRP) repair materials is of great importance for increasing the longevity of damaged surfaces in civil infrastructure in the US. This adhesion is dominated by a relatively weak interfacial bond that is attacked by environmental agents including water and UV radiation. Therefore, a strong bond between the two materials is essential in making a successful, long lasting repair. In this study, the fundamental question of the epoxy-concrete interface is investigated in terms of how it exists, how it is attacked by the environment, and how it may be improved to resist the elements. In this study, interactions between epoxy analogs and cement paste were investigated to get a fundamental understanding of the elusive interfacial bond. Various FTIR and NMR techniques were utilized to demonstrate the nature of this interaction. Only one of the small molecules (Bisphenol A), suggested a small interaction, however, based on the results it appeared that hydrogen bonding did not take place. The second part of this work focused on accelerated aging two epoxy systems, including a model DGEBA-POPDA system, and a commercial system. Mechanical testing was performed along with IR spectroscopy and diffusion modeling to determine the change in properties and mechanisms of degradation. The absorption of water up to 90°C resulted in a decrease in modulus and stress, along with an increase in strain. IR data confirmed the absorption of water within the epoxy network. With UV exposure, oxidation was demonstrated by the appearance of carbonyl peaks in the FTIR spectra. UV and water exposure gave evidence of hydrolysis through a decrease in ether groups and an increase in hydroxyl groups. While samples exposed to UV showed less of a loss in modulus as compared to those only exposed to water at the same temperature, the peak stress of samples exposed to UV was lower than those exposed to water. However, the data from the mechanical testing of the UV exposed samples was not statistically significant. The final section of this work used silane coupling agents to modify cement pastes. AFM measurements were performed to demonstrate the effectiveness of the polishing technique and uniformity of the surface, which the literature indicated was necessary for comparison purposes. The contact angle was shown to increase for the PDMS based silane, decrease for the amino based silane, and not change for the epoxy based silane. XPS data confirmed successful covalent linkages between the cement paste and silane coupling agents as evidenced by an increase in bridging O1s and Si2p electron orbitals after curve fitting.

  20. Conductive cooling in white organic light emitting diode for enhanced efficiency and life time

    NASA Astrophysics Data System (ADS)

    Tyagi, Priyanka; Kumar, Arunandan; Giri, Lalat Indu; Tuli, Suneet; Srivastava, Ritu

    2015-01-01

    We demonstrate white organic light emitting diodes with enhanced efficiency (26.8 lm/W) and life time (˜11 000 h) by improved heat dissipation through encapsulation composed of a metal (Cu, Mo, and Al) and mica sheet joined using thermally conducting epoxy. Finite element simulation is used to find effectiveness of these encapsulations for heat transfer. Device temperature is reduced by about 50% with the encapsulation. This, consequently, has improved efficiency and life time by about 30% and 60%, respectively, with respect to glass encapsulation. Conductive cooling of device is suggested as the possible cause for this enhancement.

  1. Formation and life-time of memory domains in the dissipative quantum model of brain

    E-print Network

    Alfinito, E

    2000-01-01

    We show that in the dissipative quantum model of brain the time-dependence ofthe frequencies of the electrical dipole wave quanta leads to the dynamicalorganization of the memories in space (i.e. to their localization in more orless diffused regions of the brain) and in time (i.e. to their longer orshorter life-time). The life-time and the localization in domains of the memorystates also depend on internal parameters and on the number of links that thebrain establishes with the external world. These results agree with thephysiological observations of the dynamic formation of neural circuitry whichgrows as brain develops and relates to external world.

  2. The dynamics of distance, velocity and acceleration of power output in the 30-s Wingate Anaerobic Test.

    PubMed

    Bell, W; Cobner, D

    2011-02-01

    The purpose of the present study was to analyse the dynamics of distance, velocity and acceleration of the 30-s Wingate Anaerobic Test. Participants were 53 young adult Rugby Union football players of mean age 21.6±2.5 yr, 180.5±7.2 cm height and 89.3±12.7 kg body mass. Measurements of power were obtained using a friction-belt cycle ergometer (Monark 864, Varberg, Sweden). Individual data were aligned according to peak power output, which resulted in a mean value of 1 216±256 W, compared with one of 1 180±256 W when calculated cross-sectionally (p<0.0001). The derivatives of velocity and acceleration were obtained using the mathematical software Mathcad. Distance, velocity and acceleration curves were plotted simultaneously at 1 s intervals before and after peak power output (-4 s to +28 s). The initial rise of the distance curve was the result of a general trend in decreasing positive velocities as far as peak power output, followed thereafter by a gradual deterioration of power, the result of negative velocities from peak power output to +28 s peak power output. The initial values of the acceleration curve showed a fluctuating decelerating trend of negative values to peak power output; subsequently all values remained positive running along the zero acceleration time axis. Coefficients of correlation between peak power output and power values at -1 s to -3 s were 0.80, 0.65 and 0.63 respectively (p<0.001). The relationship between velocity and acceleration was - 0.968 (p<0.01). PMID:21110285

  3. Simulation of launch and re-entry acceleration profiles for testing of shuttle and unmanned microgravity research payloads

    NASA Astrophysics Data System (ADS)

    Cassanto, J. M.; Ziserman, H. I.; Chapman, D. K.; Korszun, Z. R.; Todd, P.

    Microgravity experiments designed for execution in Get-Away Special canisters, Hitchhiker modules, and Reusable Re-entry Satellites will be subjected to launch and re-entry accelerations. Crew-dependent provisions for preventing acceleration damage to equipment or products will not be available for these payloads during flight; therefore, the effects of launch and re-entry accelerations on all aspects of such payloads must be evaluated prior to flight. A procedure was developed for conveniently simulating the launch and re-entry acceleration profiles of the Space Shuttle (3.3 and 1.7 × g maximum, respectively) and of two versions of NASA's proposed materials research Re-usable Re-entry Satellite (8 × g maximum in one case and 4 × g in the other). By using the 7 m centrifuge of the Gravitational Plant Physiology Laboratory in Philadelphia it was found possible to simulate the time dependence of these 5 different acceleration episodes for payload masses up to 59 kg. A commercial low-cost payload device, the “Materials Dispersion Apparatus” of Instrumentation Technology Associates was tested for (1) integrity of mechanical function, (2) retention of fluid in its compartments, and (3) integrity of products under simulated re-entry g-loads. In particular, the sharp rise from 1 g to maximum g-loading that occurs during re-entry in various unmanned vehicles was successfully simulated, conditions were established for reliable functioning of the MDA, and crystals of 5 proteins suspended in compartments filled with mother liquor were subjected to this acceleration load.

  4. Integrated Circuit Qualification for Space and Ground-Level Applications: Accelerated Tests and Error-Rate Predictions

    Microsoft Academic Search

    Raoul Velazco; Gilles Foucard; Paul Peronnard

    \\u000a Integrated circuits (analog, digital or mixed) sensitivity evaluation to Single Event Effects (SEE) requires specific methodologies\\u000a and dedicated tools. Indeed, such evaluation is based on data gathered from on-line tests performed in a suitable facility\\u000a (cyclotron, linear accelerator, laser , etc.). The target circuit is exposed to particles fluxes having features (energy and\\u000a range in Silicon) somewhat representative of the

  5. High-power tests of a single-cell copper accelerating cavity driven by two input couplers.

    SciTech Connect

    Horan, D.; Bromberek, D.; Meyer, D.; Waldschmidt, G.; Accelerator Systems Division (APS)

    2008-01-01

    High-power tests were conducted on a 350-MHz, single-cell copper accelerating cavity driven simultaneously by two H-loop input couplers for the purpose of determining the reliability, performance, and power-handling capability of the cavity and related components, which have routinely operated at 100-kW power levels. The test was carried out utilizing the APS 350-MHz RF Test Stand, which was modified to split the input rf power into two frac12-power feeds, each supplying power to a separate H-loop coupler on the cavity. Electromagnetic simulations of the two-coupler feed system were used to determine coupler match, peak cavity fields, and the effect of phasing errors between the coupler feed lines. The test was conducted up to a maximum total rf input power of 164-kW CW. Test apparatus details and performance data will be presented.

  6. The interplanetary shock event of November 11/12 1978 - A comprehensive test of acceleration theory

    NASA Technical Reports Server (NTRS)

    Wenzel, K.-P.; Sanderson, T. R.; Van Nes, P.; Kennel, C. F.; Scarf, F. L.; Coroniti, F. V.; Russell, C. T.; Parks, G. K.; Smith, E. J.; Feldman, W. C.

    1983-01-01

    A comprehensive study of the November 11, 12, 1978 shock event based on energetic particle, solar wind, magnetic field and wave data from the ISEE-3, -1 and -2 spacecraft has been undertaken both from the energetic and the collisionless shock point of view. The energy density of 10-50 keV protons accelerated by the shock is found to be equivalent to the upstream magnetic field energy density. The observations are in quantitative agreement with Lee's (1983) self consistent theory for the excitation of hydromagnetic waves and the acceleration of ions upstream of interplanetary shocks.

  7. Preliminary temperature accelerated life test (ALT) on lattice mismatched triple-junction concentrator solar cells-on-carriers

    NASA Astrophysics Data System (ADS)

    Orlando, Vincenzo; Espinet, Pilar; Nuñez, Neftalí; Eltermann, Fabian; Contreras, Yedileth; Bautista, Jesús; Vázquez, Manuel; Bett, Andreas W.; Algora, Carlos

    2014-09-01

    A temperature accelerated life test on concentrator lattice mismatched Ga0.37In0.63P/Ga0.83In0.17As/Ge triple-junction solar cells-on-carrier is being carried out. The solar cells have been tested at three different temperatures: 125, 145 and 165°C and the nominal photo-current condition (500X) is emulated by injecting current in darkness. The final objective of these tests is to evaluate the reliability, warranty period, and failure mechanism of these solar cells in a moderate period of time. Up to now only the test at 165°C has finished. Therefore, we cannot provide complete reliability information, but we have carried out preliminary data and failure analysis with the current results.

  8. The Implementation of the Accelerated Reader Program and Its Contribution to Success on Standardized Tests

    ERIC Educational Resources Information Center

    Myers, Marion

    2012-01-01

    This quantitative, non-experimental, correlational study investigated the effects of the Accelerated Reader (AR) program on reading achievement in elementary school students. The study also examined the perceptions of teachers and administrators about the effectiveness of the AR program. This study took place in three elementary schools located in…

  9. Proton injector acceptance tests for a Dielectric Wall Accelerator (DWA):characterisation of Advanced Injection System of Light Ions (AISLI)

    NASA Astrophysics Data System (ADS)

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhao(??), J.; Zhang, A. L.; Guo, Z. Y.; Chen, J. E.

    2014-11-01

    To demonstrate the acceleration capability of a Dielectric Wall Accelerator (DWA), a proton injector has been developed at Peking University (PKU). It is composed of a compact permanent magnet 2.45 GHz Electron Cyclotron Resonance Ion Source (PKU PMECRIS) associated with a LEBT of two electrostatic Einzel lenses [1]. This injector is named as Advanced Injector System of Light Ions (AISLI). The acceptance tests have been performed with a 40 keV-55 mA hydrogen beam successfully passing through a ? 10 mm aperture diaphragm. This diaphragm is located 200 mm downstream the plasma emission hole at the location of the future DWA entrance flange. The beam rms emittance reached about 0.10 ? mm mrad in pulsed mode. This article describes the AISLI experimental setup, the measurement principle and the obtained beam characteristics.

  10. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    SciTech Connect

    Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

    2012-05-10

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

  11. Life-time Tests of Lead-free Solder Joints on Flexible Printed Circuits

    Microsoft Academic Search

    Zsolt Illyefalvi-Vitez; Bailint Balogh; G. Farmer; A. Girulska; D. Kirkpatrick

    2007-01-01

    The electronics industry is in the transition to lead-free technology, and it is very important for all industrial performers, including small and medium size enterprises (SMEs), to keep pace with this process. FlexNoLead (Flexible Circuits Processing, Performance and Reliability using Lead-Free Soldering Process, EC Contract: COOP-CT-2004-513163), a European Commission sponsored cooperative research project is aimed at assisting SMEs in the

  12. Accelerated life testing of high voltage stator coils with enhanced PET-mica insulation system

    Microsoft Academic Search

    S. Ul Haq; R. Omranipour

    2011-01-01

    The electrical life of an enhanced PET-mica insulation system used for large rotating electrical machines was investigated by means of voltage endurance (VE) and thermal cycling tests. VE and thermal cycling tests are well understood and industry recognized test methods to qualify new or improved insulation systems. These are reliable test methods for comparing new insulation systems with service proven

  13. Testing Done for Lorentz Force Accelerators and Electrodeless Propulsion Technology Development

    NASA Technical Reports Server (NTRS)

    Pencil, Eric J.; Gilland, James H.; Arrington, Lynn A.; Kamhawi, Hani

    2004-01-01

    The NASA Glenn Research Center is developing Lorentz force accelerators and electrodeless plasma propulsion for a wide variety of space applications. These applications range from precision control of formation-flying spacecraft to primary propulsion for very high power interplanetary spacecraft. The specific thruster technologies being addressed are pulsed plasma thrusters, magnetoplasmadynamic thrusters, and helicon-electron cyclotron resonance acceleration thrusters. The pulsed plasma thruster mounted on the Earth Observing-1 spacecraft was operated successfully in orbit in 2002. The two-axis thruster system is fully incorporated in the attitude determination and control system and is being used to automatically counteract disturbances in the pitch axis of the spacecraft. Recent on-orbit operations have focused on extended operations to add flight operation time to the total accumulated thruster life. The results of the experiments pave the way for electric propulsion applications on future Earth-imaging satellites.

  14. Experimental design and analysis for accelerated degradation tests with Li-ion cells.

    SciTech Connect

    Doughty, Daniel Harvey; Thomas, Edward Victor; Jungst, Rudolph George; Roth, Emanuel Peter

    2003-08-01

    This document describes a general protocol (involving both experimental and data analytic aspects) that is designed to be a roadmap for rapidly obtaining a useful assessment of the average lifetime (at some specified use conditions) that might be expected from cells of a particular design. The proposed experimental protocol involves a series of accelerated degradation experiments. Through the acquisition of degradation data over time specified by the experimental protocol, an unambiguous assessment of the effects of accelerating factors (e.g., temperature and state of charge) on various measures of the health of a cell (e.g., power fade and capacity fade) will result. In order to assess cell lifetime, it is necessary to develop a model that accurately predicts degradation over a range of the experimental factors. In general, it is difficult to specify an appropriate model form without some preliminary analysis of the data. Nevertheless, assuming that the aging phenomenon relates to a chemical reaction with simple first-order rate kinetics, a data analysis protocol is also provided to construct a useful model that relates performance degradation to the levels of the accelerating factors. This model can then be used to make an accurate assessment of the average cell lifetime. The proposed experimental and data analysis protocols are illustrated with a case study involving the effects of accelerated aging on the power output from Gen-2 cells. For this case study, inadequacies of the simple first-order kinetics model were observed. However, a more complex model allowing for the effects of two concurrent mechanisms provided an accurate representation of the experimental data.

  15. Initial test of a fast-ramped superconducting model dipole for GSI'S proposed SIS200 accelerator

    Microsoft Academic Search

    P. Wanderert; M. Anerella; G. Ganetis; A. Ghosh; P. Joshi; A. Marone; J. Muratore; J. SCHMALZLE; R. Soika; R. Thomas; J. Kaugerts; G. Moritz; W. Hessenzahl; M. N. Wilson

    2003-01-01

    Gesellschaft fur Schwerionenforschung (GSI) has proposed a large expansion of the existing facility in Darmstadt, Germany. The proposal includes an accelerator, SIS200, with rigidity of 200 T·m that utilizes 4 T superconducting dipoles ramped at 1 T\\/s. An R&D program including both the superconductor and the magnet is directed at achieving the desired ramp rate with minimal energy loss. The

  16. Surface roughness and color characteristics of wood treated with preservatives after accelerated weathering test

    Microsoft Academic Search

    Ali Temiz; Umit C. Yildiz; Ismail Aydin; Morten Eikenes; Gry Alfredsen; Gürsel Çolakoglu

    2005-01-01

    Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2h UV-light irradiation followed by water spray for 18min. The changes on the surface of the weathered samples were characterized by roughness and

  17. In-situ diagnostics and degradation mapping of a mixed-mode accelerated stress test for proton exchange membranes

    NASA Astrophysics Data System (ADS)

    Lai, Yeh-Hung; Fly, Gerald W.

    2015-01-01

    With increasing availability of more durable membrane materials for proton exchange membrane fuel cells, there is a need for a more stressful test that combines chemical and mechanical stressors to enable accelerated screening of promising membrane candidates. Equally important is the need for in-situ diagnostic methods with sufficient spatial resolution that can provide insights into how membranes degrade to facilitate the development of durable fuel cell systems. In this article, we report an accelerated membrane stress test and a degradation diagnostic method that satisfy both needs. By applying high-amplitude cycles of electrical load to a fuel cell fed with low-RH reactant gases, a wide range of mechanical and chemical stressful conditions can be created within the cell which leads to rapid degradation of a mechanically robust Ion Power™ N111-IP membrane. Using an in-situ shorting/crossover diagnostic method on a segmented fuel cell fixture that provides 100 local current measurements, we are able to monitor the progression and map the degradation modes of shorting, thinning, and crossover leak over the entire membrane. Results from this test method have been validated by conventional metrics of fluoride release rates, physical crossover leak rates, pinhole mapping, and cross-sectional measurements.

  18. Formation and life-time of memory domains in the dissipative quantum model of brain

    E-print Network

    E. Alfinito; G. Vitiello

    2000-02-03

    We show that in the dissipative quantum model of brain the time-dependence of the frequencies of the electrical dipole wave quanta leads to the dynamical organization of the memories in space (i.e. to their localization in more or less diffused regions of the brain) and in time (i.e. to their longer or shorter life-time). The life-time and the localization in domains of the memory states also depend on internal parameters and on the number of links that the brain establishes with the external world. These results agree with the physiological observations of the dynamic formation of neural circuitry which grows as brain develops and relates to external world.

  19. Measurements of spin life time of an antimony-bound electron in silicon

    NASA Astrophysics Data System (ADS)

    Lu, T. M.; Bishop, N. C.; Tracy, L. A.; Blume-Kohout, R.; Pluym, T.; Wendt, J. R.; Dominguez, J.; Lilly, M. P.; Carroll, M. S.

    2013-03-01

    We report our measurements of spin life time of an antimony-bound electron in silicon. The device is a double-top-gated silicon quantum dot with antimony atoms implanted near the quantum dot region. A donor charge transition is identified by observing a charge offset in the transport characteristics of the quantum dot. The tunnel rates on/off the donor are first characterized and a three-level pulse sequence is then used to measure the spin populations at different load-and-wait times in the presence of a fixed magnetic field. The spin life time is extracted from the exponential time dependence of the spin populations. A spin life time of 1.27 seconds is observed at B = 3.25 T. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE, Office of Basic Energy Sciences user facility. The work was supported by the Sandia National Laboratories Directed Research and Development Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. Life-time history of suicide attempts and coronary artery disease in a community-dwelling elderly population

    E-print Network

    Boyer, Edmond

    Life-time history of suicide attempts and coronary artery disease in a community- dwelling elderly be at high risk of suicide attempts. Objective: The aim of the present study is to examine the relationship between CAD within a general population cohort and life-time history of psychiatric disorder and suicidal

  1. Reliability and Validity of a New Test of Change-of-Direction Speed for Field-Based Sports: the Change-of-Direction and Acceleration Test (CODAT)

    PubMed Central

    Lockie, Robert G.; Schultz, Adrian B.; Callaghan, Samuel J.; Jeffriess, Matthew D.; Berry, Simon P.

    2013-01-01

    Field sport coaches must use reliable and valid tests to assess change-of-direction speed in their athletes. Few tests feature linear sprinting with acute change- of-direction maneuvers. The Change-of-Direction and Acceleration Test (CODAT) was designed to assess field sport change-of-direction speed, and includes a linear 5-meter (m) sprint, 45° and 90° cuts, 3- m sprints to the left and right, and a linear 10-m sprint. This study analyzed the reliability and validity of this test, through comparisons to 20-m sprint (0-5, 0-10, 0-20 m intervals) and Illinois agility run (IAR) performance. Eighteen Australian footballers (age = 23.83 ± 7.04 yrs; height = 1.79 ± 0.06 m; mass = 85.36 ± 13.21 kg) were recruited. Following familiarization, subjects completed the 20-m sprint, CODAT, and IAR in 2 sessions, 48 hours apart. Intra-class correlation coefficients (ICC) assessed relative reliability. Absolute reliability was analyzed through paired samples t-tests (p ? 0.05) determining between-session differences. Typical error (TE), coefficient of variation (CV), and differences between the TE and smallest worthwhile change (SWC), also assessed absolute reliability and test usefulness. For the validity analysis, Pearson’s correlations (p ? 0.05) analyzed between-test relationships. Results showed no between-session differences for any test (p = 0.19-0.86). CODAT time averaged ~6 s, and the ICC and CV equaled 0.84 and 3.0%, respectively. The homogeneous sample of Australian footballers meant that the CODAT’s TE (0.19 s) exceeded the usual 0.2 x standard deviation (SD) SWC (0.10 s). However, the CODAT is capable of detecting moderate performance changes (SWC calculated as 0.5 x SD = 0.25 s). There was a near perfect correlation between the CODAT and IAR (r = 0.92), and very large correlations with the 20-m sprint (r = 0.75-0.76), suggesting that the CODAT was a valid change-of-direction speed test. Due to movement specificity, the CODAT has value for field sport assessment. Key points The change-of-direction and acceleration test (CODAT) was designed specifically for field sport athletes from specific speed research, and data derived from time-motion analyses of sports such as rugby union, soccer, and Australian football. The CODAT features a linear 5-meter (m) sprint, 45° and 90° cuts and 3-m sprints to the left and right, and a linear 10-m sprint. The CODAT was found to be a reliable change-of-direction speed assessment when considering intra-class correlations between two testing sessions, and the coefficient of variation between trials. A homogeneous sample of Australian footballers resulted in absolute reliability limitations when considering differences between the typical error and smallest worthwhile change. However, the CODAT will detect moderate (0.5 times the test’s standard deviation) changes in performance. The CODAT correlated with the Illinois agility run, highlighting that it does assess change-of-direction speed. There were also significant relationships with short sprint performance (i.e. 0-5 m and 0-10 m), demonstrating that linear acceleration is assessed within the CODAT, without the extended duration and therefore metabolic limitations of the IAR. Indeed, the average duration of the test (~6 seconds) is field sport-specific. Therefore, the CODAT could be used as an assessment of change-of-direction speed in field sport athletes. PMID:24149730

  2. Accelerating physical verification using STPRL: a novel language for test pattern generation

    NASA Astrophysics Data System (ADS)

    Nouh, Ahmed

    2007-02-01

    In this work, test-patterns, test-cases and layout-patterns generations are widely investigated in the sense of turnaround time for creation and/or modification. STPRL, a novel behavioral modeling language for test-pattern creation, is being proposed. The turn-around time for both creation and modification is hugely reduced at no degradation in either accuracy or performance. Furthermore, STPRL provides considerable performance improvements in custom test-patterns creation over available automatic layout creation tools. Our method has been verified with real data at different node-technologies and for migration from and between different technology nodes.

  3. Ischemic preconditioning accelerates muscle deoxygenation dynamics and enhances exercise endurance during the work-to-work test

    PubMed Central

    Kido, Kohei; Suga, Tadashi; Tanaka, Daichi; Honjo, Toyoyuki; Homma, Toshiyuki; Fujita, Satoshi; Hamaoka, Takafumi; Isaka, Tadao

    2015-01-01

    Ischemic preconditioning (IPC) improves maximal exercise performance. However, the potential mechanism(s) underlying the beneficial effects of IPC remain unknown. The dynamics of pulmonary oxygen uptake (VO2) and muscle deoxygenation during exercise is frequently used for assessing O2 supply and extraction. Thus, this study examined the effects of IPC on systemic and local O2 dynamics during the incremental step transitions from low- to moderate- and from moderate- to severe-intensity exercise. Fifteen healthy, male subjects were instructed to perform the work-to-work cycling exercise test, which was preceded by the control (no occlusion) or IPC (3 × 5 min, bilateral leg occlusion at >300 mmHg) treatments. The work-to-work test was performed by gradually increasing the exercise intensity as follows: low intensity at 30 W for 3 min, moderate intensity at 90% of the gas exchange threshold (GET) for 4 min, and severe intensity at 70% of the difference between the GET and VO2 peak until exhaustion. During the exercise test, the breath-by-breath pulmonary VO2 and near-infrared spectroscopy-derived muscle deoxygenation were continuously recorded. Exercise endurance during severe-intensity exercise was significantly enhanced by IPC. There were no significant differences in pulmonary VO2 dynamics between treatments. In contrast, muscle deoxygenation dynamics in the step transition from low- to moderate-intensity was significantly faster in IPC than in CON (27.2 ± 2.9 vs. 19.8 ± 0.9 sec, P < 0.05). The present findings showed that IPC accelerated muscle deoxygenation dynamics in moderate-intensity exercise and enhanced severe-intensity exercise endurance during work-to-work test. The IPC-induced effects may result from mitochondrial activation in skeletal muscle, as indicated by the accelerated O2 extraction. PMID:25952936

  4. High power testing of the 402.5 MHZ and 805 MHZ RF windows for the spallation neutron source accelerator

    SciTech Connect

    Cummings, K. A. (Karen Ann); De Baca, J. M. (John M.); Harrison, J. S. (John S.); Rodriguez, M. B. (Manuelita B.); Torrez, P. A. (Phillip A.); Warner, D. K. (David K.)

    2003-01-01

    Hisorically, Radio Frequency (RF) windows have been a common point of failure in input power couplers; therefore, reliable RF windows are critical to the success of the Spallation Neutron Source (SNS) project. The normal conducting part of the SNS accelerator requires six RF windows at 402.5 MHz and eight RF windows at 805 MHz[l]. Each RF window will transmit up to 180 kW of average power and 2.5 MW peak power at 60 Hz with 1.2 millisecond pulses. The RF windows, designed and manufactured by Thales, were tested at the full average power for 4 hours to ensure no problems with the high average power and then tested to an effective forward power level of 10 MW by testing at 2.5 MW forward power into a short and varying the phase of the standing wave. The sliding short was moved from 0 to 180 degrees to ensure no arcing or breakdown problems occur in any part of the window. This paper discusses the results of the high power testing of both the 402.5 MHz and the 805 MHz RF windows. Problems encountered during testing and the solutions for these problems are discussed.

  5. Accelerated UV test methods and selection criteria for encapsulants of photovoltaic modules

    Microsoft Academic Search

    Michael D. Kempe

    2008-01-01

    Photovoltaic modules are exposed to extremely harsh conditions of heat, humidity, high voltage, mechanical stress, thermal cycling and ultraviolet (UV) radiation. The current qualification tests (e.g. IEC 61215) do not require UV exposure high enough to evaluate a 20+ year lifespan. Methods to quickly test the UV durability of photovoltaic materials are needed. In considering encapsulant materials, the initial performance

  6. MECHANO-EROSION: A NOVEL TEST METHODOLOGY TO ACCELERATE EROSION IN ROLLING CONTACT FATIGUE EXPERIMENTS

    Microsoft Academic Search

    Balamurugan KARUNAMURTHY; Mark HADFIELD

    Rolling contact fatigue testing of rolling elements with low saturation temperature lubricants result in several difficulties. Mainly, uncontrolled phase changes due to flow dynamics often causes difficulties in assessing the lubricant effect on fatigue life. This work simulates these conditions for testing in a controlled environment to understand the mechanism of material wear. A rotary tribometer was modified to allow

  7. Methodology for designing accelerated aging tests for predicting life of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Gaines, G. B.; Thomas, R. E.; Derringer, G. C.; Kistler, C. W.; Bigg, D. M.; Carmichael, D. C.

    1977-01-01

    A methodology for designing aging tests in which life prediction was paramount was developed. The methodology builds upon experience with regard to aging behavior in those material classes which are expected to be utilized as encapsulant elements, viz., glasses and polymers, and upon experience with the design of aging tests. The experiences were reviewed, and results are discussed in detail.

  8. Redshift-Drift as a Test for Discriminating Between Decelerating Inhomogeneous and Accelerating Universe Models

    NASA Astrophysics Data System (ADS)

    Mishra, Priti; Célérier, Marie-Noëlle Singh, Tejinder P.

    2015-01-01

    Exact inhomogeneous solutions of Einstein's equations have been used in the literature to build models reproducing the cosmological data without dark energy. However, owing to the degrees of freedom pertaining to these models, it is necessary to get rid of the degeneracy often exhibited by the problem of distinguishing between them and accelerating universe models. We give an overview of redshift drift in inhomogeneous cosmologies, and explain how it serves to this purpose. One class of models which fits the data is the Szekeres Swiss-cheese class where non-spherically symmetric voids exhibit a typical size of about 400 Mpc. We present our calculation of the redshift drift in this model, and compare it with the results obtained by other authors for alternate scenarios.

  9. Test particle acceleration in a numerical MHD experiment of an anemone jet

    NASA Astrophysics Data System (ADS)

    Rosdahl, K. J.; Galsgaard, K.

    2010-02-01

    Aims: To use a 3D numerical MHD experiment representing magnetic flux emerging into an open field region as a background field for tracing charged particles. The interaction between the two flux systems generates a localised current sheet where MHD reconnection takes place. We investigate how efficiently the reconnection region accelerates charged particles and what kind of energy distribution they acquire. Methods: The particle tracing is done numerically using the Guiding Center Approximation on individual data sets from the numerical MHD experiment. Results: We derive particle and implied photon distribution functions having power law forms, and look at the impact patterns of particles hitting the photosphere. We find that particles reach energies far in excess of those seen in observations of solar flares. However the structure of the impact region in the photosphere gives a good representation of the topological structure of the magnetic field. Three movies are only available in electronic form at http://www.aanda.org

  10. Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

    SciTech Connect

    Amann, J.; Bane, K.; /SLAC

    2009-10-30

    This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

  11. Experimental test and life estimation of the OLED at normal working stress based on the luminance degradation model.

    PubMed

    Zhang, J P; Wang, C; Chen, X; Cheng, G L; Qiu, Y J; Shen, M-H H

    2015-06-01

    In order to accurately acquire the life time information for the organic light emitting diode (OLED), an experiment based on the normal stress life test was carried out to gain the data for the luminance degradation tests. The luminance degradation model of OLED was established based on the Weibull function and the least square method. Combined with luminance degradation data, Weibull parameters were estimated, the qualitative and the quantitative relationship between the initial luminance and the OLED life was obtained, and the life estimation of the product was achieved. Numerical results show that the test scheme is feasible, the luminance degradation model proves to be reliable for the OLED life estimation, and the fitting accuracy is very high by comparison with the test data fluctuation. Moreover, the real life time of the OLED is measured, which can verify the validity of the assumptions used in accelerated life test methods and provide manufacturers and customers with significant guidelines. PMID:25044460

  12. More on accelerating physical verification using STPRL: a novel language for test pattern generation

    NASA Astrophysics Data System (ADS)

    Nouh, Ahmed

    2007-03-01

    In this work, test-patterns, test-cases and layout-patterns generations are widely investigated in the sense of turnaround time for creation and/or modification. STPRL, a novel behavioral modeling language for test-pattern creation, is being proposed. The turn-around time for both creation and modification is hugely reduced at no degradation in either accuracy or performance. Furthermore, STPRL provides considerable performance improvements in custom testpatterns creation over available automatic layout creation tools. Our method has been verified with real data at different node-technologies and for migration from and between different technology nodes.

  13. USCAR FUEL CELL TECH TEAM CELL COMPONENT ACCELERATED STRESS TEST PROTOCOLS

    E-print Network

    and are less expensive than the current generation of polymer membranes. The associated testing protocols of polymer electrolyte membrane (PEM) fuel cell components under simulated automotive drive cycle conditions

  14. Corrosion behaviour of weathering steel in diluted Qinghai salt lake water in a laboratory accelerated test that involved cyclic wet\\/dry conditions

    Microsoft Academic Search

    J. Wang; Z. Y. Wang; W. Ke

    2010-01-01

    The corrosion behaviour of CortenA weathering steel has been investigated using a laboratory accelerated test that involved cyclic wet\\/dry conditions in Qinghai salt lake water diluted 30 times. The characteristics of the rust layers on tested samples were observed by SEM and EPMA, analyzed by IRS and XRD, and studied by polarization and EIS measurements. The weight loss was almost

  15. Lifetime Measurements of Carbon and Diamond Stripping Foils Tested in the Fermi National Accelerator Laboratory Linac

    Microsoft Academic Search

    Trivia Penns Frazier

    A foil testing apparatus was fabricated to test carbon versus diamond stripper foil life expectancy. The goal of this experiment is to find a target material more suitable for the proposed multi-mega-watt 8-GeV proton driver and booster system, which uses multiturn charge-exchange injection. Preparation includes tuning bending and quadrupole magnets and doing calculations of pertinent theoretical values, such as instantaneous

  16. An accelerated stability test using the peroxide value as an index

    Microsoft Academic Search

    A. E. King; H. L. Roschen; W. H. Irwin

    1933-01-01

    Summary  A quick stability test for lard is described which depends on the peroxide content for identification of the rancid point.\\u000a By its use ordinary samples of lard can be evaluated for stability in a working day. Oleo oil also is being tested by this\\u000a method. It is applicable to edible fats and oils and hydrogenated shortenings. Typical peroxide curves for

  17. Microwave power coupler for a superconducting multiple-cell cavity for accelerator application and its testing procedures

    SciTech Connect

    Li, Jianjian; /IIT, Chicago

    2008-12-01

    Superconducting cavity resonators offer the advantage of high field intensity for a given input power, making them an attractive contender for particle accelerator applications. Power coupling into a superconducting cavity employed in a particle accelerator requires unique provisions to maintain high vacuum and cryogenic temperature on the cavity side, while operating with ambient conditions on the source side. Components introduced to fulfill mechanical requirements must show negligible obstruction of the propagation of the microwave with absence of critical locations that may give rise to electron multipaction, leading to a multiple section design, instead of an aperture, a probe, or a loop structure as found in conventional cavities. A coaxial power coupler for a superconducting multiple-cell cavity at 3.9 GHz has been developed. The cavity is intended to be employed as an accelerator to provide enhanced electron beam quality in a free-electron laser in Hamburg (FLASH) user facility. The design of the coupler called for two windows to sustain high vacuum in the cavity and two bellows to accommodate mechanical dimensional changes resulting from cryogenics. Suppression of multipacting was accomplished by the choice of conductor dimensions and materials with low second yield coefficients. Prior to integration with the cavity, the coupler was tested for intrinsic properties in a back-to-back configuration and conditioned for high-power operation with increasing power input. Maximum incident power was measured to be 61 kW. When integrated with the superconducting cavity, a loaded quality factor of 9 x 10{sup 5} was measured by transient method. Coupler return loss and insertion loss were estimated to be around -21 dB and -0.2 dB, respectively.

  18. Assembly and Test of SQ01b, a Nb3Sn Quadrupole Magnet for the LHC Accelerator Research Program

    SciTech Connect

    Ferracin, P.; Ambrosio, G.; Bartlett, S. E.; Bordini, B.; Carcagno, R.H.; Caspi, S.; Dietderich, D.R.; Feher, S.; Gourlay, S.A.; Hafalia, A.R.; Lamm, M.J.; Lietzke, A.F.; Mattafirri, S.; McInturff, A.D.; Orris, D.F.; Pischalnikov, Y.M.; Sabbi, G.L.; Sylvester, C.D.; Tartaglia, M.A.; Velev, G.V.; Zlobin, A.V.; Kashikhin, V.V.

    2006-06-01

    The US LHC Accelerator Research Program (LARP) consists of four US laboratories (BNL, FNAL, LBNL, and SLAC) collaborating with CERN to achieve a successful commissioning of the LHC and to develop the next generation of Interaction Region magnets. In 2004, a large aperture Nb{sub 3}Sn racetrack quadrupole magnet (SQ01) has been fabricated and tested at LBNL. The magnet utilized four subscale racetrack coils and was instrumented with strain gauges on the support structure and directly over the coil's turns. SQ01 exhibited training quenches in two of the four coils and reached a peak field in the conductor of 10.4 T at a current of 10.6 kA. After the test, the magnet was disassembled, inspected with pressure indicating films, and reassembled with minor modifications. A second test (SQ01b) was performed at FNAL and included training studies, strain gauge measurements and magnetic measurements. Magnet inspection, test results, and magnetic measurements are reported and discussed, and a comparison between strain gauge measurements and 3D finite element computations is presented

  19. How soccer players head the ball: a test of Optic Acceleration Cancellation theory with virtual reality.

    PubMed

    McLeod, Peter; Reed, Nick; Gilson, Stuart; Glennerster, Andrew

    2008-06-01

    We measured the movements of soccer players heading a football in a fully immersive virtual reality environment. In mid-flight the ball's trajectory was altered from its normal quasi-parabolic path to a linear one, producing a jump in the rate of change of the angle of elevation of gaze (alpha) from player to ball. One reaction time later the players adjusted their speed so that the rate of change of alpha increased when it had been reduced and reduced it when it had been increased. Since the result of the player's movement was to regain a value of the rate of change close to that before the disturbance, the data suggest that the players have an expectation of, and memory for, the pattern that the rate of change of alpha will follow during the flight. The results support the general claim that players intercepting balls use servo control strategies and are consistent with the particular claim of Optic Acceleration Cancellation theory that the servo strategy is to allow alpha to increase at a steadily decreasing rate. PMID:18472123

  20. Experiments in non-perturbative electron beam characterization with the MIT microwiggler at the Accelerator Test Facility at BNL

    SciTech Connect

    Qiu, X.; Babzien, M.; Ben-Zvi, I.; Graves, W. [and others

    1996-11-01

    We report a new method through which the properties of an electron beam at linac energies may be studied using the spontaneous emission of a microwiggler. The setup is simple and the measurement efficient. A simple set of scaling laws is derived to describe broadening of spontaneous emission in a narrow bandwidth radiation cone. The relations suggest that one can obtain beam divergence from a cone at large angle in a single shot measurement. A systematic series of experiments was performed with the MIT Microwiggler at the Accelerator Test Facility at BNL which demonstrated the response of the cone to changes in the beam quality, Estimates of divergence can be obtained from the measurements of the radiation cone.

  1. Architecture, implementation, and testing of a multiple-shell gas injection system for high current implosions on the Z accelerator.

    PubMed

    Krishnan, Mahadevan; Elliott, Kristi Wilson; Madden, Robert E; Coleman, P L; Thompson, John R; Bixler, Alex; Lamppa, D C; McKenney, J L; Strizic, T; Johnson, D; Johns, O; Vigil, M P; Jones, B; Ampleford, D J; Savage, M E; Cuneo, M E; Jones, M C

    2013-06-01

    Tests are ongoing to conduct ~20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ~2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system. PMID:23822342

  2. Architecture, implementation, and testing of a multiple-shell gas injection system for high current implosions on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Krishnan, Mahadevan; Elliott, Kristi Wilson; Madden, Robert E.; Coleman, P. L.; Thompson, John R.; Bixler, Alex; Lamppa, D. C.; McKenney, J. L.; Strizic, T.; Johnson, D.; Johns, O.; Vigil, M. P.; Jones, B.; Ampleford, D. J.; Savage, M. E.; Cuneo, M. E.; Jones, M. C.

    2013-06-01

    Tests are ongoing to conduct ˜20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ˜2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system.

  3. Design and tests for the fast Faraday cup of the ALPI post-accelerator

    Microsoft Academic Search

    M. Bellato; A. Dainelli; M. Poggi

    1996-01-01

    This paper describes the design of the coaxial and strip-line fast Faraday cup as a tool, with an appropriate broadband amplifier and a sampling oscilloscope, to determine the bunch length down to 200 ps FWHM. Some beam tests and the preliminary results for the beam energy measurement with the same detector are also reported.

  4. Big Bang Nucleosynthesis: Accelerator tests and can (UC OMEGA)B really be large

    Microsoft Academic Search

    David N. Schramm

    1987-01-01

    The first collider tests of cosmological theory are now underway. The number of neutrino families in nature, Nnu, plays a key role in elementary particle physics as well as in the synthesis of the light elements during the early evolution of the Universe. Standard Big Bang Nucleosynthesis argues for Nnu = 3 plus or minus 1. Current limits on Nnu

  5. Big Bang nucleosynthesis: Accelerator tests and can. cap omega. \\/sub B\\/ really be large

    Microsoft Academic Search

    1987-01-01

    The first collider tests of cosmological theory are now underway. The number of neutrino families in nature, N\\/sub nu\\/, plays a key role in elementary particle physics as well as in the synthesis of the light elements during the early evolution of the Universe. Standard Big Bang Nucleosynthesis argues for N\\/sub nu\\/ = 3 +- 1. Current limits on N\\/sub

  6. TESTING MODELS OF ACCRETION-DRIVEN CORONAL HEATING AND STELLAR WIND ACCELERATION FOR T TAURI STARS

    SciTech Connect

    Cranmer, Steven R., E-mail: scranmer@cfa.harvard.ed [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2009-11-20

    Classical T Tauri stars are pre-main-sequence objects that undergo simultaneous accretion, wind outflow, and coronal X-ray emission. The impact of plasma on the stellar surface from magnetospheric accretion streams is likely to be a dominant source of energy and momentum in the upper atmospheres of these stars. This paper presents a set of models for the dynamics and heating of three distinct regions on T Tauri stars that are affected by accretion: (1) the shocked plasmas directly beneath the magnetospheric accretion streams, (2) stellar winds that are accelerated along open magnetic flux tubes, and (3) closed magnetic loops that resemble the Sun's coronal active regions. For the loops, a self-consistent model of coronal heating was derived from numerical simulations of solar field-line tangling and turbulent dissipation. Individual models are constructed for the properties of 14 well-observed stars in the Taurus-Auriga star-forming region. Predictions for the wind mass-loss rates are, on average, slightly lower than the observations, which suggests that disk winds or X-winds may also contribute to the measured outflows. For some of the stars, however, the modeled stellar winds do appear to contribute significantly to the measured mass fluxes. Predictions for X-ray luminosities from the shocks and loops are in general agreement with existing observations. The stars with the highest accretion rates tend to have X-ray luminosities dominated by the high-temperature (5-10 MK) loops. The X-ray luminosities for the stars having lower accretion rates are dominated by the cooler accretion shocks.

  7. Evaluation of the reliability of commercial concentrator triple-junction solar cells by means of accelerated life tests (ALT)

    NASA Astrophysics Data System (ADS)

    Espinet-González, Pilar; Algora, Carlos; Núñez, Neftalí; Orlando, Vincenzo; Vázquez, Manuel; Bautista, Jesús; Araki, Kenji

    2013-09-01

    A temperature accelerated life test on commercial concentrator lattice-matched GaInP/GaInAs/Ge triple-junction solar cells has been carried out. The solar cells have been tested at three different temperatures: 119, 126 and 164 °C and the nominal photo-current condition (820 X) has been emulated by injecting current in darkness. All the solar cells have presented catastrophic failures. The failure distributions at the three tested temperatures have been fitted to an Arrhenius-Weibull model. An Arrhenius activation energy of 1.58 eV was determined from the fit. The main reliability functions and parameters (reliability function, instantaneous failure rate, mean time to failure, warranty time) of these solar cells at the nominal working temperature (80 °C) have been obtained. The warranty time obtained for a failure population of 5 % has been 69 years. Thus, a long-term warranty could be offered for these particular solar cells working at 820 X, 8 hours per day at 80 °C.

  8. Accelerated corrosion testing, evaluation and durability design of bonded post-tensioned concrete tendons

    NASA Astrophysics Data System (ADS)

    Salas Pereira, Ruben Mario

    2003-06-01

    In the last few years, the effectiveness of cement grout in galvanized or polyethylene ducts, the most widely used corrosion protection system for multistrand bonded post-tensioned concrete tendons, has been under debate, due to significant tendon corrosion damage, several reported failures of individual tendons as well as a few collapses of non-typical structures. While experience in the USA has been generally good, some foreign experience has been less than satisfactory. This dissertation is part of a comprehensive research program started in 1993, which has the objectives to examine the use of post-tensioning in bridge substructures, identify durability concerns and existing technology, develop and carry out an experimental testing program, and conclude with durability design guidelines. Three experimental programs were developed: A long term macrocell corrosion test series, to investigate corrosion protection for internal tendons in precast segmental construction; a long term beam corrosion test series, to examine the effects of post-tensioning on corrosion protection as affected by crack width; and, a long term column corrosion test series, to examine corrosion protection in vertical elements. Preliminary design guidelines were developed previously in the overall study by the initial researchers, after an extensive literature review. This dissertation scope includes continuation of exposure testing of the macrocell, beam and column specimens, performing comprehensive autopsies of selected specimens and updating the durability design guidelines based on the exposure testing and autopsy results. After autopsies were performed, overall findings indicate negative durability effects due to the use of mixed reinforcement, small concrete covers, galvanized steel ducts, and industry standard or heat-shrink galvanized duct splices. The width of cracks was shown to have a direct negative effect on specimen performance. Grout voids were found to be detrimental to the durability of both galvanized ducts and strand. Relying on epoxy and galvanized bar coatings was also found inappropriate because of local attack. On the other hand, very positive effects were found with the use of high performance concrete, high post-tensioning levels, plastic ducts, and sound epoxy filling at the joints.

  9. Synchronization extends the life time of the desired behavior of globally coupled systems

    PubMed Central

    Kapitaniak, Marcin; Lazarek, Mateusz; Nielaczny, Michal; Czolczynski, Krzysztof; Perlikowski, Przemyslaw; Kapitaniak, Tomasz

    2014-01-01

    Synchronization occurs widely in natural and technological world, but it has not been widely used to extend the life time of the desirable behavior of the coupled systems. Here we consider the globally coupled system consisting of n units and show that the initial synchronous state extends the lifetime of desired behavior of the coupled system in the case when the excitation of one or few units is suddenly (breakdown of energy supply) or gradually (as the effect of aging and fatigue) switched off. We give evidence that for the properly chosen coupling the energy transfer from the excited units allows unexcited units to operate in the desired manner. As proof of concept, we examine the system of coupled externally excited rotating pendula. After the partial excitation switch off the initial complete synchronization of all pendula is replaced by phase synchronization with a constant phase shift between the clusters of excited and unexcited pendula. Our results show that the described extension of the system's life time occurs for the wide range of coupling parameters and is robust to the external perturbations. PMID:24633215

  10. Evaluation of HVDC cables for the St. Lawrence crossing of Hydro-Quebec 500 kV DC Line. Part 1; Dielectric and accelerated aging tests on prototypes

    Microsoft Academic Search

    D. Coudere; N. G. Trinh; M. Belec; M. Chaaban; J. Leduc; Y. Beausejour

    1992-01-01

    This paper describes the dielectric and accelerated aging tests on prototype {plus minus}500 kV dc oil-filled self-contained cables. The extensive test program was required to evaluate the High-Voltage cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper relates the main elements of the test program. It describes the required

  11. Evaluation of HVDC cables for the St. Lawrence crossing of Hydro Quebec 500 kV DC line. I. Dielectric and accelerated aging tests on prototypes

    Microsoft Academic Search

    D. Couderc; N. G. Trinh; M. Belec; M. Chaaban; J. Leduc; Y. Beausejour

    1991-01-01

    The dielectric and accelerated aging tests on prototype ±500 kV DC oil-filled self-contained cables are discussed. The extensive test program was required to evaluate the high-voltage cables for the St. Lawrence river crossing of the ±500 kV Quebec-New England HVDC power transmission system. The main elements of the test program are related. The required insulation levels, the characteristics of the

  12. An RF Waveguide Distribution System for the ILC Test Accelerator at Fermilab's NML

    SciTech Connect

    Nantista, Christopher; Adolphsen, Chris; Bowden, Gordon; Swent, Richard; McKee, Bobby; /SLAC

    2007-06-27

    An ILC R&D facility is being constructed in the NML building at Fermilab which, in addition to an injector and beam dump with spectrometer, will contain up to three cryomodules of ILC-type superconducting 9-cell cavities. This linac will be powered by a single klystron. As part of SLAC's contribution to this project, we will provide a distribution network in WR650 waveguide to the various cavity couplers. In addition to commercial waveguide components and circulators and loads, this system will include adjustable tap-offs, and customized hybrids. In one configuration, the circulators will be removed to test pair-wise cancellation of cavity reflections through hybrids. The system will be pressurized with nitrogen to 3 bar absolute to avoid the need for SF{sub 6}. The full distribution system for the first cryomodule will be delivered and installed later this year. We describe the design of the system and completed RF testing.

  13. Development of an Accelerated Test Method for the Determination of Susceptibility to Atmospheric Corrosion

    NASA Technical Reports Server (NTRS)

    Ambrose, John R.

    1991-01-01

    The theoretical rationale is presented for use of a repetitive cyclic current reversal voltammetric technique for characterization of localized corrosion processes, including atmospheric corrosion. Applicability of this proposed experimental protocol is applied to characterization of susceptibility to crevice and pitting corrosion, atmospheric corrosion and stress corrosion cracking. Criteria upon which relative susceptibility is based were determined and tested using two iron based alloys commonly in use at NASA-Kennedy; A36 (a low carbon steel) and 4130 (a low alloy steel). Practicality of the procedure was demonstrated by measuring changes in anodic polarization behavior during high frequency current reversal cycles of 25 cycles per second with 1 mA/sq cm current density amplitude in solutions containing Cl anions. The results demonstrated that, due to excessive polarization which affects conductivity of barrier corrosion product layers, A36 was less resistant to atmospheric corrosion than its 4130 counterpart; behavior which was also demonstrated during exposure tests.

  14. Ethylene propylene cable degradation during LOCA research tests: tensile properties at the completion of accelerated aging

    SciTech Connect

    Bustard, L.D.

    1982-05-01

    Six ethylene-propylene rubber (EPR) insulation materials were aged at elevated temperature and radiation stress exposures common in cable LOCA qualification tests. Material samples were subjected to various simultaneous and sequential aging simulations in preparation for accident environmental exposures. Tensile properties subsequent to the aging exposure sequences are reported. The tensile properties of some, but not all, specimens were sensitive to the order of radiation and elevated temperature stress exposure. Other specimens showed more severe degradation when simultaneously exposed to radiation and elevated temperature as opposed to the sequential exposure to the same stresses. Results illustrate the difficulty in defining a single test procedure for nuclear safety-related qualification of EPR elastomers. A common worst-case sequential aging sequence could not be identified.

  15. Neural Network Models of Simple Mechanical Systems Illustrating the Feasibility of Accelerated Life Testing

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.; Jones, Steven P.; Jansen, Ralph

    1996-01-01

    A complete evaluation of the tribological characteristics of a given material/mechanical system is a time-consuming operation since the friction and wear process is extremely systems sensitive. As a result, experimental designs (i.e., Latin Square, Taguchi) have been implemented in an attempt to not only reduce the total number of experimental combinations needed to fully characterize a material/mechanical system, but also to acquire life data for a system without having to perform an actual life test. Unfortunately, these experimental designs still require a great deal of experimental testing and the output does not always produce meaningful information. In order to further reduce the amount of experimental testing required, this study employs a computer neural network model to investigate different material/mechanical systems. The work focuses on the modeling of the wear behavior, while showing the feasibility of using neural networks to predict life data. The model is capable of defining which input variables will influence the tribological behavior of the particular material/mechanical system being studied based on the specifications of the overall system.

  16. Vacuum seals design and testing for a linear accelerator of the National Spallation Neutron Source

    SciTech Connect

    Z. Chen; C. Gautier; F. Hemez; N. K. Bultman

    2000-02-01

    Vacuum seals are very important to ensure that the Spallation Neutron Source (SNS) Linac has an optimum vacuum system. The vacuum joints between flanges must have reliable seals to minimize the leak rate and meet vacuum and electrical requirements. In addition, it is desirable to simplify the installation and thereby also simplify the maintenance required. This report summarizes an investigation of the metal vacuum seals that include the metal C-seal, Energized Spring seal, Helcoflex Copper Delta seal, Aluminum Delta seal, delta seal with limiting ring, and the prototype of the copper diamond seals. The report also contains the material certifications, design, finite element analysis, and testing for all of these seals. It is a valuable reference for any vacuum system design. To evaluate the suitability of several types of metal seals for use in the SNS Linac and to determine the torque applied on the bolts, a series of vacuum leak rate tests on the metal seals have been completed at Los Alamos Laboratory. A copper plated flange, using the same type of delta seal that was used for testing with the stainless steel flange, has also been studied and tested. A vacuum seal is desired that requires significantly less loading than a standard ConFlat flange with a copper gasket for the coupling cavity assembly. To save the intersegment space the authors use thinner flanges in the design. The leak rate of the thin ConFlat flange with a copper gasket is a baseline for the vacuum test on all seals and thin flanges. A finite element analysis of a long coupling cavity flange with a copper delta seal has been performed in order to confirm the design of the long coupling cavity flange and the welded area of a cavity body with the flange. This analysis is also necessary to predict a potential deformation of the cavity under the combined force of atmospheric pressure and the seating load of the seal. Modeling of this assembly has been achieved using both HKS/Abaqus and COSMOS/M, which are finite element packages for analysis of coupled, nonlinear problems. From these studies, the appropriate seals that are reliable for SNS long coupling cavities and beamline joints were determined.

  17. Structural Benchmark Testing for Stirling Convertor Heater Heads

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Kalluri, Sreeramesh; Bowman, Randy R.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) has identified high efficiency Stirling technology for potential use on long duration Space Science missions such as Mars rovers, deep space missions, and lunar applications. For the long life times required, a structurally significant design limit for the Stirling convertor heater head is creep deformation induced even under relatively low stress levels at high material temperatures. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and much creep data is available for the proposed Inconel-718 (IN-718) and MarM-247 nickel-based superalloy materials of construction. However, very little experimental creep information is available that directly applies to the atypical thin walls, the specific microstructures, and the low stress levels. In addition, the geometry and loading conditions apply multiaxial stress states on the heater head components, far from the conditions of uniaxial testing. For these reasons, experimental benchmark testing is underway to aid in accurately assessing the durability of Stirling heater heads. The investigation supplements uniaxial creep testing with pneumatic testing of heater head test articles at elevated temperatures and with stress levels ranging from one to seven times design stresses. This paper presents experimental methods, results, post-test microstructural analyses, and conclusions for both accelerated and non-accelerated tests. The Stirling projects use the results to calibrate deterministic and probabilistic analytical creep models of the heater heads to predict their life times.

  18. Cell Component Accelerated Stress Test and Polarization Curve Protocols for Polymer Electrolyte Membrane Fuel Cells

    NSDL National Science Digital Library

    United States Driving Research and Innovation for Vehicle Efficiency and Energy Sustainability (USDRIVE)

    This document contains test protocols to determine the performance and durability of fuel cell components such as electrocatalysts and supports, membranes, and membrane electrode assemblies (MEAs). These protocols were established with the intent to be used as a common industry standard when assessing durability of different polymer electrolyte membranes (PEM) in fuel cells for automotive applications and to be compared against DOE and FreedomCar targets. The resulting data may also help to model the performance of the fuel cell under variable load conditions and the effects of ageing on performance.

  19. The effects of irradiation and EtO-treatment on ultrahigh molecular weight polyethylene acetabular cups following accelerated aging: Degradation of mechanical properties and morphology changes during hip simulator tests

    Microsoft Academic Search

    Paola Taddei; Saverio Affatato; Mirko Rocchi; Concezio Fagnano; Marco Viceconti

    2008-01-01

    The present study was aimed at investigating the effects of the sterilization method and accelerated aging on the wear and morphology of ultrahigh molecular weight polyethylene. In a first test, gamma- and EtO-sterilized acetabular cups were tested in a hip joint simulator for two million cycles. After the test, the cups underwent an accelerated aging treatment (80°C, 4 weeks in

  20. Accelerator-based tests of radiation shielding properties of materials used in human space infrastructures.

    PubMed

    Lobascio, C; Briccarello, M; Destefanis, R; Faraud, M; Gialanella, G; Grossi, G; Guarnieri, V; Manti, L; Pugliese, M; Rusek, A; Scampoli, P; Durante, M

    2008-03-01

    Shielding is the only practical countermeasure for the exposure to cosmic radiation during space travel. It is well known that light, hydrogenated materials, such as water and polyethylene, provide the best shielding against space radiation. Kevlar and Nextel are two materials of great interest for spacecraft shielding because of their known ability to protect human space infrastructures from meteoroids and debris. We measured the response to simulated heavy-ion cosmic radiation of these shielding materials and compared it to polyethylene, Lucite (PMMA), and aluminum. As proxy to galactic nuclei we used 1 GeV n iron or titanium ions. Both physics and biology tests were performed. The results show that Kevlar, which is rich in carbon atoms (about 50% in number), is an excellent space radiation shielding material. Physics tests show that its effectiveness is close (80-90%) to that of polyethylene, and biology data suggest that it can reduce the chromosomal damage more efficiently than PMMA. Nextel is less efficient as a radiation shield, and the expected reduction on dose is roughly half that provided by the same mass of polyethylene. Both Kevlar and Nextel are more effective than aluminum in the attenuation of heavy-ion dose. PMID:18301097

  1. Component Selection, Accelerated Testing, and Improved Modeling of AMTEC Systems for Space Power (abstract)

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; Suitor, J.; O'Connor, D.

    1993-01-01

    Alkali metal thermal to electric converter (AMTEC) designs for space power are numerous, but selection of materials for construction of long-lived AMTEC devices has been limited to electrodes, current collectors, and the solid electrolyte. AMTEC devices with lifetimes greater than 5 years require careful selection and life testing of all hot-side components. The likely selection of a remote condensed design for initial flight test and probable use with a GPHS in AMTEC powered outer planet probes requires the device to be constructed to tolerate T greater than 1150K, as well as exposure to Na(sub (g)), and Na(sub (liq)) on the high pressure side. The temperatures involved make critical high strength and chemical resistance to Na containing Na(sub 2)O. Selection among materials which can be worked should not be driven by ease of fabricability, as high temperature stability is the critical issue. These concepts drive the selection of Mo alloys for Na(sub (liq)) containment in AMTEC cells for T to 1150K operation, as they are significantly stronger than comparable NB or Ta alloys, are less soluble in Na(sub (liq)) containing dissolved Na(sub 2)O, are workable compared to W alloys (which might be used for certain components), and are ductile at the T greater than 500K of proposed AMTEC modules in space applications.

  2. Study of the degradation mechanisms of carbon-supported platinum fuel cells catalyst via different accelerated stress test

    NASA Astrophysics Data System (ADS)

    Zhang, Yuanliang; Chen, Siguo; Wang, Yao; Ding, Wei; Wu, Rui; Li, Li; Qi, Xueqiang; Wei, Zidong

    2015-01-01

    A combination method based on three different accelerated stress test (AST) protocols along with the monitoring of electrochemical surface area (ECSA), oxygen reduction reaction (ORR) activities, X-Ray photoelectron spectrometer (XPS), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS) response is introduced to investigate the degradation mechanisms of carbon-supported platinum (Pt/C) catalyst. By comparing the ECSA and ORR activity loss under different AST protocols, we revealed that the activity loss in AST can be divided into recoverable activity loss and unrecoverable activity loss. The recoverable activity loss is attributed to the reduction of Pt oxide or partially due to the removal of CO formed during carbon corrosion. The unrecoverable activity loss is ascribed to the Pt dissolution/re-deposition, agglomeration, detachment and carbon corrosion. XPS results show that the Pt dissolution/re-deposition in AST can be detected by using a more negative potential window. TEM images and analysis confirmed that the Pt growth mode in this study is mainly due to the Pt agglomeration rather than dissolution/re-deposition. EIS analysis reveals that the alternative decomposition/formation of oxygen containing groups over time is the main corrosion pathway of carbon support. These findings are very important for understanding Pt/C catalyst degradation and are also useful for developing fast test protocol for screening new durable catalyst materials.

  3. Comparison of environmental degradation in Hanwha 295 W and SunPower 320 W photovoltaic modules via accelerated lifecycle testing

    NASA Astrophysics Data System (ADS)

    Biggie, R.; Lai, T.; Huang, W.-J.; Potter, B. G.; Simmons-Potter, K.

    2014-10-01

    Lifecycle testing of full-scale photovoltaic (PV) modules was conducted in a large-sized, accelerated-degradation chamber in our labs that enables full-solar-spectrum irradiance, temperature, and humidity control. In-situ measurement of both polycrystalline and monocrystalline silicon PV module energy conversion characteristics were examined under environmental lifecycle conditions representative of Tucson, AZ. Specifically, the performance degradation of a Hanwha 295 W polycrystalline PV module and of a SunPower 320 W monocrystalline PV module were evaluated and compared. Results indicate that the initial efficiency of the polycrystalline module and the subsequent annual degradation occurred within expected ranges for that system. In contrast, the single-crystal module exhibited both a significant decrease in PV module efficiency during the test cycle, and early evidence of environmentally-induced materials degradation across the module. The temperature and time-dependence of PV module behavior were extracted to provide insight into early-stage performance degradation under conditions approximating field-relevant environments.

  4. Micron-scale laser-wire scanner for the KEK Accelerator Test Facility extraction line Stewart T. Boogert,* Grahame A. Blair, Gary Boorman, Alessio Bosco, Lawrence C. Deacon,

    E-print Network

    Sheldon, Nathan D.

    [4,5], ATF damping ring laser wire [6], and PETRA laser wire [7]. A method for measuring submicronMicron-scale laser-wire scanner for the KEK Accelerator Test Facility extraction line Stewart T 3RH, United Kingdom (Received 16 July 2010; published 6 December 2010) A laser-wire transverse

  5. IEEE TRANSACTIONS ON RELIABILITY, 1996, VOL. 45, NO. 3, pp. 491-498 1 A Bayes Approach to Step-Stress Accelerated Life Testing

    E-print Network

    van Dorp, Johan René

    IEEE TRANSACTIONS ON RELIABILITY, 1996, VOL. 45, NO. 3, pp. 491-498 1 A Bayes Approach to Step develops a Bayes model for step-stress accelerated life testing. The failure times at each stress level of the failure rates in both the prior and posterior estimates. Methods are developed for Bayes point estimates

  6. Kenneth J. Turner. Formally-Based Testing of Radiotherapy Accelerators. In Robert N. Procter and Mark Rouncefield, editors, Proc. Dependability in

    E-print Network

    Turner, Ken

    Kenneth J. Turner. Formally-Based Testing of Radiotherapy Accelerators. In Robert N. Procter and Mathematics, University of Stirling Stirling FK9 4LA, UK Email kjt@cs.stir.ac.uk 20th March 2001 Abstract/Medical Devices). The three-year project is being undertaken from October 2000 at the University of Stirling

  7. Kenneth J. Turner and Qian Bing. Systematic Testing of Radiotherapy Accelerators. In Hartmut Ehrig, Berndt J. Kramer and Atilla Ertas, editors,

    E-print Network

    Turner, Ken

    , designed and tested to very high standards. A review of standards for software-controlled medical devices medical systems [8], [9]. A number of subsidiary standards concern accelerators [10]. The US Food and Drug of medical equipment (e.g. the Medical Devices Directive [2]). More general software development standards

  8. Experimental Testing of the Gigabit IPSec-Compliant Implementations of Rijndael and Triple DES Using SLAAC-1V FPGA Accelerator Board

    Microsoft Academic Search

    Pawel Chodowiec; Kris Gaj; Peter Bellows; Brian Schott

    2001-01-01

    In this paper, we present the results of the first phase of a project aimed at implementing a full suite of IPSec cryptographic transformations in reconfigurable hardware. Full implementations of the new Advanced Encryption Standard, Rijndael, and the older American federal standard, Triple DES, were developed and experimentally tested using the SLAAC-1V FPGA accelerator board, based on Xilinx Virtex 1000

  9. Simulation of launch and re-entry acceleration profiles for testing of shuttle and unmanned microgravity research payloads

    Microsoft Academic Search

    J. M. Cassanto; H. I. Ziserman; D. K. Chapman; Z. R. Korszun; P. Todd

    1988-01-01

    Microgravity experiments designed for execution in Get-Away Special canisters, Hitchhiker modules, and Reusable Re-entry Satellites will be subjected to launch and re-entry accelerations. Crew-dependent provisions for preventing acceleration damage to equipment or products will not be available for these payloads during flight; therefore, the effects of launch and re-entry accelerations on all aspects of such payloads must be evaluated prior

  10. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  11. Physics design of a 10 MeV injector test stand for an accelerator-driven subcritical system

    NASA Astrophysics Data System (ADS)

    Yan, Fang; Pei, Shilun; Geng, Huiping; Meng, Cai; Zhao, Yaliang; Sun, Biao; Cheng, Peng; Yang, Zheng; Ouyang, Huafu; Li, Zhihui; Tang, Jingyu; Wang, Jianli; Sui, Yefeng; Dai, Jianping; Sha, Peng; Ge, Rui

    2015-05-01

    The 10 MeV accelerator-driven subcritical system (ADS) Injector I test stand at Institute of High Energy Physics (IHEP) is a testing facility dedicated to demonstrate one of the two injector design schemes [Injector Scheme-I, which works at 325 MHz], for the ADS project in China. The injector is composed of two parts, the linac part and the beam dump line. The former is designed on the basis of 325 MHz four-vane type copper structure radio frequency quadrupole and superconducting (SC) spoke cavities with ? =0.12 . The latter is designed to transport the beam coming out of the SC section of the linac to the beam dump, where the beam transverse profile is fairly enlarged and unformed to simplify the beam target design. The SC section consists of two cryomodules with 14 ? =0.12 Spoke cavities, 14 solenoid and 14 BPMs in total. The first challenge in the physics design comes from the necessary space required for the cryomodule separation where the periodical lattice is destroyed at a relatively lower energy of ˜5 MeV . Another challenge is the beam dump line design, as it will be the first beam dump line being built by using a step field magnet for the transverse beam expansion and uniformity in the world. This paper gives an overview of the physics design study together with the design principles and machine construction considerations. The results of an optimized design, fabrication status and end to end simulations including machine errors are presented.

  12. Life-Time Of Internal Solitary Waves On Oceanic Shelves Based On Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Talipova, T.; Pelinovsky, E.; Grimshaw, R.; Kurkin, A.

    2004-05-01

    Due to the horizontal variability of oceanic hydrology (density and current stratification) and the variable depth over the continental shelf, internal solitary waves transform as they propagate shorewards into the coastal zone. If the background variability is smooth enough, a solitary wave possesses a soliton-like form with varying amplitude and phase. This stage is studied in detail in the framework of the variable-coefficient extended Korteweg-de Vries equation where the variation of the solitary wave parameters can be described analytically through an asymptotic description of a slowly-varying solitary wave. Direct numerical simulation of the variable-coefficient extended Korteweg-de Vries equation is performed for several oceanic shelves (North-west Shelf of Australia, Malin Shelf Edge, Arctic Shelf) to demonstrate the applicability of the asymptotic theory. It is shown that the solitary wave may maintain its soliton-like form for large distances (up to 100 km), and this confirms why internal solitons are observed widely in the world's oceans. In some cases the background stratification contains critical points (when the coefficients of the nonlinear terms in the extended Korteweg-de Vries equation change sign), or does not vary sufficiently smoothly; in such cases the solitary wave deforms a group of secondary waves. This stage is studied numerically. These results are used to estimate the life-time of the internal solitons on oceanic shelves.

  13. Lead-bismuth target design for the subcritical multiplier (SCM) of the accelerator driven test facility (ADTF).

    SciTech Connect

    Gohar, Y.; Finck, P. J.; Krajtl, L.; Herceg, J.; Pointer, W. D.; Saiveau, J.; Sofu, T.; Hanson, A. L.; Todosow, M.; Koploy, M.; Mijatovic, P.

    2002-04-18

    A lead-bismuth eutectic (LBE) target design concept has been developed to drive the subcritical multiplier (SCM) of the accelerator-driven test facility (ADTF). This report gives the target design description, the results from the parametric studies, and the design analyses including physics, heat-transfer, hydraulics, structural, radiological, and safety analyses. The design is based on a coaxial geometrical configuration to minimize the target footprint and to maximize the utilization of the spallation neutrons. The target is installed vertically along the SCM axis. LBE is the target material and the target coolant. Ferritic steel (HT-9 alloy) is the selected structural material based on the current database and the design analyses. Austenitic steel (Type 316 stainless steel) is the backup choice. A uniform proton beam is employed to perform the spallation process. The proton beam has 8.33-mA current and 8.14-cm radius resulting in a current density of 40 {micro}A/cm{sup 2}. The beam power is 5 MW and the proton energy is 600 MeV. The beam tube has 10-cm radius to accommodate the halo current. A hemi-spherical geometry is used for the target window, which is connected to the beam tube. A conical target window with a rounded tip is also considered since it has a lower average temperature relative to the spherical geometry. The beam tube is enclosed inside two coaxial tubes to provide inlet and outlet manifolds for the LBE coolant. The inlet and the outlet coolant manifolds and the proton beam are entered from the top above the SCM. Several design constraints are developed and utilized for the target design process to satisfy different engineering requirements and to minimize the design development time and cost.

  14. New methods for optical distance indicator and gantry angle quality control tests in medical linear accelerators: image processing by using a 3D phantom

    PubMed Central

    Shandiz, Mahdi Heravian; Anvari, Kazem; Khalilzadeh, Mohammadmahdi

    2015-01-01

    Purpose In order to keep the acceptable level of the radiation oncology linear accelerators, it is necessary to apply a reliable quality assurance (QA) program. Materials and Methods The QA protocols, published by authoritative organizations, such as the American Association of Physicists in Medicine (AAPM), determine the quality control (QC) tests which should be performed on the medical linear accelerators and the threshold levels for each test. The purpose of this study is to increase the accuracy and precision of the selected QC tests in order to increase the quality of treatment and also increase the speed of the tests to convince the crowded centers to start a reliable QA program. A new method has been developed for two of the QC tests; optical distance indicator (ODI) QC test as a daily test and gantry angle QC test as a monthly test. This method uses an image processing approach utilizing the snapshots taken by the CCD camera to measure the source to surface distance (SSD) and gantry angle. Results The new method of ODI QC test has an accuracy of 99.95% with a standard deviation of 0.061 cm and the new method for gantry angle QC has a precision of 0.43°. The automated proposed method which is used for both ODI and gantry angle QC tests, contains highly accurate and precise results which are objective and the human-caused errors have no effect on the results. Conclusion The results show that they are in the acceptable range for both of the QC tests, according to AAPM task group 142. PMID:25874177

  15. Observational test of shock drift and Fermi acceleration on a seed particle population upstream of earth's bow shock

    NASA Technical Reports Server (NTRS)

    Anagnostopoulos, G. C.; Sarris, E. T.; Krimigis, S. M.

    1988-01-01

    The efficiency of proposed shock acceleration mechanisms as they operate at the bow shock in the presence of a seed energetic particle population was examined using data from simultaneous observations of energetic solar-origin protons, carried out by the IMP 7 and 8 spacecraft in the vicinity of the quasi-parallel (dawn) and quasi-perpendicular (dusk) regions of the earth's bow shock, respectively. The results of observations (which include acceleration effects in the intensities of the energetic protons with energies as high as 4 MeV observed at the vicinity of the dusk bow shock, but no evidence for any particle acceleration at the energy equal to or above 50 keV at the dawn side of the bow shock) indicate that the acceleration of a seed particle population occurs only at the quasi-perpendicular bow shock through shock drift acceleration and that the major source of observed upstream ion populations is the leakage of magnetospheric ions of energies not less than 50 keV, rather than in situ acceleration.

  16. Physically Based Rendering Intersection Acceleration

    E-print Network

    Kazhdan, Michael

    Physically Based Rendering (600.657) Intersection Acceleration #12;Intersection Testing Accelerated partitions: Group objects into clusters Cluster volumes may overlap #12;Uniform (Voxel) Grid Acceleration Acceleration · Trace rays through grid cells ­ Fast ­ Incremental A B C D E F Only check primitives

  17. Rutting Performance of Airport Hot-Mix Asphalt Characterized by Laboratory Performance Testing, Full-Scale Accelerated Pavement Testing, and Finite Element Modeling

    E-print Network

    Rushing, John Ford

    2014-04-25

    test, the dynamic modulus test, and the Asphalt Pavement Analyzer (APA) test as potential performance tests to accompany airport HMA mixture design with a goal of providing acceptable threshold test results that predict rutting performance under...

  18. Combined approach to damaged wire ropes life-time assessment based on NDT results and rope mechanics

    Microsoft Academic Search

    A. Vorontsov; V. Volokhovsky; D. Slesarev

    2011-01-01

    Principles of strength assessment and life-time prediction of deteriorated wire ropes based on magnetic NDT technique are presented. The measured loss of metallic cross-section area due to abrasion, corrosion etc. and local wire breaks are treated as input data for mechanical model of rope structure. The rope is interpreted as a system with two degrees of freedom that enables to

  19. DC drift activation energy of LiNbO3 optical modulators based on thousands of hours of active accelerated aging tests

    Microsoft Academic Search

    Hirotoshi Nagata; Yagang Li; Ian Croston; David R. Maack; Andy Appleyard

    2002-01-01

    Activation energy Ea in the drift of a separate dc bias port of x-cut LiNbO3 (LN) optical modulators has been estimated based on thousands of hours of accelerated aging test data. The obtained drift curves show peaking and suggest an absence of catastrophically increasing bias voltages in these x-cut LN modulators. The Ea values calculated from the first positive drift

  20. Accelerated life test of the USDOE OC-OTEC experimental system refurbished with magnetic bearings for the 3rd stage vacuum compressor. Final report

    Microsoft Academic Search

    Vega

    1997-01-01

    This report documents the accelerated life test (time-to-failure) performed, at the request of DOE, to evaluate the viability of the magnetic bearing system installed in the stage 3 vacuum pump. To this effect the plant was successfully operated for over 500 hours during the period September-November 1996. The first part of this report discusses system performance by deriving subsystem and

  1. Stability of CIGS Solar Cells and Component Materials Evaluated by a Step-Stress Accelerated Degradation Test Method: Preprint

    SciTech Connect

    Pern, F. J.; Noufi, R.

    2012-10-01

    A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15oC and then a 15% relative humidity (RH) increment step, beginning from 40oC/40%RH (T/RH = 40/40) to 85oC/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. The best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 ?m to 0.50 ?m on the cells. No clear 'stepwise' feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ? 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and 'capacitor quality' factor (CPE-P), which were related to the cells? p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ? 70/70. At T/RH = 85/70, substantial blistering of BZO layers on CIGS cell pieces was observed that was not seen on BZO/glass, and a CdS/CIGS sample displayed a small darkening and then flaking feature. Additionally, standard AlNi grid contact was less stable than thin Ni grid contact at T/RH ? 70/70. The edge sealant and moisture-blocking films were effective to block moisture ingress, as evidenced by the good stability of most CIGS solar cells and device components at T/RH = 85/70 for 704 h, and by preservation of the initial blue color on the RH indicator strips. The SSADT experiment is ongoing to be completed at T/RH = 85/85.

  2. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  3. Evaluation of shelf life of flavored dehydrated products using accelerated shelf life testing and the Weibull Hazard sensory analysis

    Microsoft Academic Search

    M. Bili; P. S. Taoukis

    1998-01-01

    The shelf life of foods is a function of their composition, processing, packaging and environmental factors, most notably temperature. For dehydrated foods, end of shelf life is usually signaled by an unacceptable loss of sensory attributes. Since the time to reach this level of unacceptability, under normal storage conditions, is targeted to be 12 to 24 months, techniques of Accelerated

  4. The effect of magnetic topology on particle acceleration in a 3D reconnecting current sheet. Test-particle approach

    Microsoft Academic Search

    V. V. ZHARKOVA; O. V. AGAPITOV

    Electron and proton acceleration by a drifted super-Dreicer electric field is investigated in a strongly compressed non-neutral reconnecting current sheet (NRCS). The guiding field is assumed to be constant within an RCS and parallel to the direction of drifted electric field. The other two magnetic field components, transverse and tangential, are considered to vary exponentially and linearly with distances from

  5. Well width dependence of the carrier life time in InGaAs\\/InP quantum wells

    Microsoft Academic Search

    U. Cebulla; G. Bacher; G. Mayer; A. Forchel; W. T. Tsang; M. Razeghi

    1989-01-01

    Investigations of the well width dependence of the radiative excitonic life time of InGaAs\\/InP quantum wells are reported, for well widths between 1 nm and 50 nm. The luminescence of the 1-1 transition of the quantum wells is detected via time resolved frequency up-conversion with the exciting Nd-YAG laser. In our experiments the time constants reveal an interesting phenomena with

  6. Correlations of Capacitance-Voltage Hysteresis with Thin-Film CdTe Solar Cell Performance During Accelerated Lifetime Testing

    SciTech Connect

    Albin, D.; del Cueto, J.

    2011-03-01

    In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 degrees C.

  7. PV module degradation caused by thermomechanical stress: real impacts of outdoor weathering versus accelerated testing in the laboratory

    Microsoft Academic Search

    W. Herrmann; N. Bogdanski; F. Reil; M. Köhl; K.-A. Weiss; M. Assmus; M. Heck

    2010-01-01

    Temperature cycling tests are part of the IEC 61215 qualification testing of crystalline silicon (c-Si) PV modules for evaluating PV module degradation caused by the impact of thermo-mechanically induced stresses. The defined temperature gradient and the cycle time by far exceed the actual impact of natural weathering, however. As a contribution to comparisons between laboratory testing and natural weathering our

  8. Switched matrix accelerator

    SciTech Connect

    Whittum, David H.; Tantawi, Sami G.

    2001-01-01

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We also provide an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392 GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium.

  9. Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

    SciTech Connect

    Mark, J.W.K.

    1982-03-22

    Calculations suggest that experiments relating to disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics. In this regard, the low beam emittance of suggested multi-beam designs are very useful. Possibly even higher focal spot brightness could be obtained by plasma lenses which involve external fields on the beam which is stripped to a higher charge state by passing through a plasma cell. Preliminary results suggest that intensities approx. 10/sup 13/ - 10/sup 14/ W/cm/sup 2/ are achievable. Given these intensities, deposition experiments with heating of disks to greater than a million degrees Kelvin (100 eV) are expected.

  10. Effects of load connection in accelerated aging of aSi:H solar cell for long term reliability test

    Microsoft Academic Search

    Sang Hyun Park; Kyung Min Kim; Jun-Sik Cho; Jeong Chul Lee; Gi-Hwan Kang; Duck-Kyun Choi; Kyung Hoon Yoon; Jinsoo Song

    2010-01-01

    To establish reliable model for long term reliability of a-Si:H PV module, outdoor field aging results and indoor light soaking test has been investigated. For the appropriate comparisons, one type of outdoor system modules and test cells has been fabricated from the same commercial module production line. Severe early stage degradation in outdoor site has been resulted and compared to

  11. 38 CFR 21.7142 - Accelerated payments, payment of tuition assistance top-up, and licensing or certification test...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...b) Amount of tuition assistance top-up. The amount of tuition assistance...

  12. 38 CFR 21.7142 - Accelerated payments, payment of tuition assistance top-up, and licensing or certification test...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...b) Amount of tuition assistance top-up. The amount of tuition assistance...

  13. 38 CFR 21.7142 - Accelerated payments, payment of tuition assistance top-up, and licensing or certification test...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...b) Amount of tuition assistance top-up. The amount of tuition assistance...

  14. 38 CFR 21.7142 - Accelerated payments, payment of tuition assistance top-up, and licensing or certification test...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...b) Amount of tuition assistance top-up. The amount of tuition assistance...

  15. 38 CFR 21.7142 - Accelerated payments, payment of tuition assistance top-up, and licensing or certification test...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...payments, payment of tuition assistance top-up, and licensing or certification test reimbursement...b) Amount of tuition assistance top-up. The amount of tuition assistance...

  16. Black Ink and Red Ink (BIRI) Testing: A Testing Method to Evaluate Both Recall and Recognition Learning in Accelerated Adult-Learning Courses

    ERIC Educational Resources Information Center

    Rodgers, Joseph Lee; Rodgers, Jacci L.

    2011-01-01

    We propose, develop, and evaluate the black ink-red ink (BIRI) method of testing. This approach uses two different methods within the same test administration setting, one that matches recognition learning and the other that matches recall learning. Students purposively define their own tradeoff between the two approaches. Evaluation of the method…

  17. High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty.

    PubMed

    Saikko, Vesa

    2015-01-21

    The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3 Hz and an average sliding velocity of 27.4 mm/s was designed. The pins circularly translated at high frequency (1.0 mm per cycle, 24.8 Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5 Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8 mg per 24 h, which was six times higher than that in the established 1 Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation. PMID:25498368

  18. Acceleration of trapped particles and beams

    E-print Network

    Er'el Granot; Boris Malomed

    2011-07-30

    The dynamics of a quantum particle bound by an accelerating delta-functional potential is investigated. Three cases are considered, using the reference frame moving along with the {\\delta}-function, in which the acceleration is converted into the additional linear potential. (i) A stationary regime, which corresponds to a resonance state, with a minimum degree of delocalization, supported by the accelerating potential trap. (ii) A pulling scenario: an initially bound particle follows the accelerating delta-functional trap, within a finite time. (iii) The pushing scenario: the particle, which was initially localized to the right of the repulsive delta-function, is shoved to the right by the accelerating potential. For the two latter scenarios, the life time of the trapped particle, and the largest velocity to which it can be accelerated while staying trapped, are found. Analytical approximations are developed for the cases of small and large accelerations in the pulling regime, and also for a small acceleration in the stationary situation, and in the regime of pushing. The same regimes may be realized by Airy-like planar optical beams guided by a narrow bending potential channel or crest. Physical estimates are given for an atom steered by a stylus of a scanning tunneling microscope (STM), and for the optical beam guided by a bending stripe.

  19. Accelerated tests for long-term prediction of corrosion in austenitic stainless steels and Ni-Fe-Cr-Mo alloys

    SciTech Connect

    Sridhar, N.; Dunn, D.; Cragnolino, G. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    1996-10-01

    The effect of applied potential and chloride concentration on localized corrosion and stress corrosion cracking (SCC) of austenitic stainless steels (SSs) and Ni-base alloys was studied. The repassivation potential, E{sub rp} for deep pits was the same as that for crevice corrosion. Laboratory tests over a two-year period and field experience have shown that the E{sub rp} is a conservative parameter to predict the occurrence of both these failure modes. For type 316L SS, the U-bend SCC test was found to be more conservative than the slow strain rates tests under controlled potential conditions for a variety of chloride concentrations. No SCC was observed below the E{sub rp}. The E{sub rp} was also found to correlate with boiling nitric acid test results and the degree of sensitization of alloy 825. The difficulties in using cyclic potentiodynamic polarization tests for assessing localized corrosion, of highly alloyed materials such as alloy C-22 are pointed out. This study is important for high-level nuclear waste disposal programs.

  20. The need for speed: testing acceleration for estimating animal travel rates in terrestrial dead-reckoning systems.

    PubMed

    Bidder, Owen R; Soresina, Marion; Shepard, Emily L C; Halsey, Lewis G; Quintana, Flavio; Gómez-Laich, Agustina; Wilson, Rory P

    2012-02-01

    Numerous methods are currently available to track animal movements. However, only one of these, dead-reckoning, has the capacity to provide continuous data for animal movements over fine scales. Dead-reckoning has been applied almost exclusively in the study of marine species, in part due to the difficulty of accurately measuring the speed of terrestrial species. In the present study we evaluate the use of accelerometers and a metric known as overall dynamic body acceleration (ODBA) as a proxy for the measurement of speed for use in dead-reckoning. Data were collated from previous studies, for 10 species locomoting on a treadmill and their ODBA measured by an attached data logger. All species except one showed a highly significant linear relationship between speed and ODBA; however, there was appreciable inter- and intra-specific variance in this relationship. ODBA was then used to estimate speed in a simple trial run of a dead-reckoning track. Estimating distance travelled using speed derived from prior calibration for ODBA resulted in appreciable errors. We describe a method by which these errors can be minimised, by periodic ground-truthing (e.g., by GPS or VHF telemetry) of the dead-reckoned track and adjusting the relationship between speed and ODBA until actual known positions and dead-reckoned positions accord. PMID:22244455

  1. Target life time of laser ion source for low charge state ion production

    SciTech Connect

    Kanesue,T.; Tamura, J.; Okamura, M.

    2008-06-23

    Laser ion source (LIS) produces ions by irradiating pulsed high power laser shots onto the solid state target. For the low charge state ion production, laser spot diameter on the target can be over several millimeters using a high power laser such as Nd:YAG laser. In this case, a damage to the target surface is small while there is a visible crater in case of the best focused laser shot for high charge state ion production (laser spot diameter can be several tens of micrometers). So the need of target displacement after each laser shot to use fresh surface to stabilize plasma is not required for low charge state ion production. We tested target lifetime using Nd:YAG laser with 5 Hz repetition rate. Also target temperature and vacuum condition were recorded during experiment. The feasibility of a long time operation was verified.

  2. Multilayer insulation for the interconnect region in the Accelerator System String Test: A practical engineering approach for a new scheme of design and installation bridges

    SciTech Connect

    Baritchi, D.; Jalloh, A.

    1993-04-01

    In order to minimize the heat leak in the Accelerator System String Test (ASST) inter-connect region, shield bridges and multilayer insulation (MLI) are provided. A sliding joint between shield bridges on adjacent magnets accommodates the contraction that occurs during cooldown. In the original design of the MLI bridges, thermal contraction was provided for by compressing the MLI. During assembly of the interconnect region, it was realized that there was not enough room for the required compression. This resulted in a redesign of the MLI bridges. The new scheme involves splitting and overlapping the MLI. This scheme has worked very well in subsequent assembly of the interconnect region. In this paper, we are going to present the new design scheme. We will also compare this design with the original design and present its advantages.

  3. Models of fR cosmic acceleration that evade solar system tests Wayne Hu1,2

    E-print Network

    Hu, Wayne

    dark energy--a new, exotic form of matter--but rather from a modification of gravity that appears be tested by future, percent- level measurements of the linear power spectrum, while they remain disappear. The scalar degree of free- dom would become massive in the high-density solar vicinity and hidden

  4. Analytical and experimental investigation of the feasibility of accelerated lifetime testing of materials exposed to an atomic oxygen beam

    NASA Technical Reports Server (NTRS)

    Albridge, Royal; Barnes, Alan; Tolk, Norman

    1993-01-01

    The interaction of atomic particles with surfaces is of both scientific and technological interest. Past work emphasizes the measurement of high-energy sputtering yields. Very little work utilized low-energy beams for which chemical and electronic effects can be important. Even less work has been carried out using well-defined low-energy projectiles. The use of low-energy, reactive projectiles permits one to investigate surface processes that have not been well characterized. As the energy of the projectile decreases, the collisional cascades and spikes, that are common for high-energy projectiles, become less important, and chemical and electronic effects can play a significant role. Aspects of particle-surface interactions are of concern in several areas of technology. For example, the erosion, desorption, and glow of surfaces of spacecraft in orbit are important in the arena of space technology. The materials studied under this contract are of possible use on the exterior portions of the power generation system of Space Station Freedom. Under the original designs, Space Station Freedom's power generation system would generate potential differences on the surface as high as 200 volts. Ions in the plasma that often surround orbiting vehicles would be accelerated by these potentials leading to bombardment and erosion of the exposed surfaces. The major constituent of the atmosphere, approximately 90 percent, in the low earth orbit region is atomic oxygen. Since atomic oxygen is extremely reactive with most materials, chemical effects can arise in addition to the physical sputtering caused by the acceleration of the oxygen ions. Furthermore, the incident oxygen ions can remain embedded in the exposed surfaces, altering the chemical composition of the surfaces. Since the effective binding energy of a chemically altered surface can be quite different from that of the pure substrate, the sputtering yield of a chemically altered surface is usually different also. The low-energy O+ sputtering yield measurements, reported here, will help quantify the erosion rates for materials exposed to the low-earth orbit environment. These measurements are of technological importance in another respect. In most surface analysis techniques, a surface is bombarded with ions, electrons or photons. Information concerning the structure of the surface and near-surface bulk, abundance of impurities and defects, as well as other surface properties are obtained either from the desorbed species or from the scattered projectiles. Because of their low penetration depth, low-energy ions provide an advantage over other techniques because they provide information that is more indicative of conditions on the surface rather than integrated effects arising from deeper in the bulk. A better understanding of the microscopic processes involved in these interactions is not only of basic scientific interest, but will also aid the scientific community by increasing the accuracy and usefulness of these surface analysis techniques.

  5. Surface modification of nano-silica on the ligament advanced reinforcement system for accelerated bone formation: primary human osteoblasts testing in vitro and animal testing in vivo

    NASA Astrophysics Data System (ADS)

    Li, Mengmeng; Wang, Shiwen; Jiang, Jia; Sun, Jiashu; Li, Yuzhuo; Huang, Deyong; Long, Yun-Ze; Zheng, Wenfu; Chen, Shiyi; Jiang, Xingyu

    2015-04-01

    The Ligament Advanced Reinforcement System (LARS) has been considered as a promising graft for ligament reconstruction. To improve its biocompatibility and effectiveness on new bone formation, we modified the surface of a polyethylene terephthalate (PET) ligament with nanoscale silica using atom transfer radical polymerization (ATRP) and silica polymerization. The modified ligament is tested by both in vitro and in vivo experiments. Human osteoblast testing in vitro exhibits an ~21% higher value in cell viability for silica-modified grafts compared with original grafts. Animal testing in vivo shows that there is new formed bone in the case of a nanoscale silica-coated ligament. These results demonstrate that our approach for nanoscale silica surface modification on LARS could be potentially applied for ligament reconstruction.The Ligament Advanced Reinforcement System (LARS) has been considered as a promising graft for ligament reconstruction. To improve its biocompatibility and effectiveness on new bone formation, we modified the surface of a polyethylene terephthalate (PET) ligament with nanoscale silica using atom transfer radical polymerization (ATRP) and silica polymerization. The modified ligament is tested by both in vitro and in vivo experiments. Human osteoblast testing in vitro exhibits an ~21% higher value in cell viability for silica-modified grafts compared with original grafts. Animal testing in vivo shows that there is new formed bone in the case of a nanoscale silica-coated ligament. These results demonstrate that our approach for nanoscale silica surface modification on LARS could be potentially applied for ligament reconstruction. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01439e

  6. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  7. Evaluation of HVDC cables for the St. Lawrence River crossing of Hydro-Quebec's 500 kV DC line. Part 2; Cable testing facility for dielectric and accelerated aging

    Microsoft Academic Search

    N. G. Trinh; D. Couderc; P. Faucher; M. Chaaban; M. Belec; J. Leduc

    1992-01-01

    This paper describes the new cable testing facility at IREQ for long-term accelerated aging tests on HV cables. This test facility was required as part of an extensive program to evaluate the high-voltage cables for the river crossing of Hydro-Quebec's new transmission lines rated 800 kV AC and {plus minus}500 kV DC. The first application was for the evaluation of

  8. Evaluation of HVDC cables for the St. Lawrence river crossing of Hydro-Quebec's 500 kV DC line. II. Cable testing facility for dielectric and accelerated aging

    Microsoft Academic Search

    N. G. Trinh; D. Couderc; P. Faucher; M. Chaaban; M. Belec; J. Leduc

    1991-01-01

    For pt.I see ibid., p.101-9 (1991). The new cable testing facility at IREQ for long-term accelerated aging tests on HV cables is described. This test facility was required as part of an extensive program to evaluate the high-voltage cables for the river crossing of Hydro-Quebec's new transmission lines rated 800 kV AC and ±500 kV DC. The first application was

  9. Procedure for developing experimental designs for accelerated tests for service-life prediction. [for solar cell modules

    NASA Technical Reports Server (NTRS)

    Thomas, R. E.; Gaines, G. B.

    1978-01-01

    Recommended design procedures to reduce the complete factorial design by retaining information on anticipated important interaction effects, and by generally giving up information on unconditional main effects are discussed. A hypothetical photovoltaic module used in the test design is presented. Judgments were made of the relative importance of various environmental stresses such as UV radiation, abrasion, chemical attack, temperature, mechanical stress, relative humidity and voltage. Consideration is given to a complete factorial design and its graphical representation, elimination of selected test conditions, examination and improvement of an engineering design, and parametric study. The resulting design consists of a mix of conditional main effects and conditional interactions and represents a compromise between engineering and statistical requirements.

  10. Present Status And First Results of the Final Focus Beam Line at the KEK Accelerator Test Facility

    SciTech Connect

    Bambade, P.; /Orsay /KEK, Tsukuba; Alabau Pons, M.; /Valencia U., IFIC; Amann, J.; /SLAC; Angal-Kalinin, D.; /Daresbury; Apsimon, R.; /Oxford U., JAI; Araki, S.; Aryshev, A.; /KEK, Tsukuba; Bai, S.; /Beijing, Inst. High Energy Phys.; Bellomo, P.; /SLAC; Bett, D.; /Oxford U., JAI; Blair, G.; /Royal Holloway, U. of London; Bolzon, B.; /Savoie U.; Boogert, S.; Boorman, G.; /Royal Holloway, U. of London; Burrows, P.N.; Christian, G.; Coe, P.; Constance, B.; /Oxford U., JAI; Delahaye, Jean-Pierre; /CERN; Deacon, L.; /Royal Holloway, U. of London; Elsen, E.; /DESY /Valencia U., IFIC /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Savoie U. /Fermilab /Ecole Polytechnique /KEK, Tsukuba /Kyungpook Natl. U. /KEK, Tsukuba /Pohang Accelerator Lab. /Kyoto U., Inst. Chem. Res. /Savoie U. /Daresbury /Tokyo U. /Royal Holloway, U. of London /Kyungpook Natl. U. /Pohang Accelerator Lab. /Tokyo U. /KEK, Tsukuba /SLAC /University Coll. London /KEK, Tsukuba /SLAC /Royal Holloway, U. of London /KEK, Tsukuba /Tokyo U. /SLAC /Tohoku U. /KEK, Tsukuba /Tokyo U. /Pohang Accelerator Lab. /Brookhaven /SLAC /Oxford U., JAI /SLAC /Orsay /KEK, Tsukuba /Oxford U., JAI /Orsay /Fermilab /Tohoku U. /Manchester U. /CERN /SLAC /Tokyo U. /KEK, Tsukuba /Oxford U., JAI /Hiroshima U. /KEK, Tsukuba /CERN /KEK, Tsukuba /Oxford U., JAI /Ecole Polytechnique /SLAC /Oxford U., JAI /Fermilab /SLAC /Liverpool U. /SLAC /Tokyo U. /SLAC /Tokyo U. /KEK, Tsukuba /SLAC /CERN

    2011-11-11

    ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U.S. scientists. The present status and first results are described.

  11. Failure Engineering Study and Accelerated Stress Test Results for the Mars Global Surveyor Spacecraft's Power Shunt Assemblies

    NASA Technical Reports Server (NTRS)

    Gibbel, Mark; Larson, Tim

    1999-01-01

    Due to a post launch failure of a part a new plan for the Mars Global Surveyor was developed. This new plan involved the addition of many deep thermal cycles to the Power Shunt Assemblies (PSA's). This new plan exceeds the previous acceptance cold level, and fatigue life on packaging design. This presentation reviews the experiments that were used to test the capabilities of the PSA to function in the new situation. It also reviews the analyses preformed to verify the most likely failure mechanism, and the likelihood that these failures would impact the new mission requirements.

  12. Accelerating Ground-Test Cycle Time: The Six-Minute Model Change and Other Visions for the 21st Century

    NASA Technical Reports Server (NTRS)

    Kegelman, Jerome T.

    1998-01-01

    The advantage of managing organizations to minimize product development cycle time has been well established. This paper provides an overview of the wind tunnel testing cycle time reduction activities at Langley Research Center (LaRC) and gives the status of several improvements in the wind tunnel productivity and cost reductions that have resulted from these activities. Processes have been examined and optimized. Metric data from monitoring processes provides guidance for investments in advanced technologies. The most promising technologies under implementation today include the use of formally designed experiments, a diverse array of quick disconnect technology and the judicious use of advanced electronic and information technologies.

  13. Accelerated reliability testing of highly aligned single-walled carbon nanotube networks subjected to DC electrical stressing.

    PubMed

    Strus, Mark C; Chiaramonti, Ann N; Kim, Young Lae; Jung, Yung Joon; Keller, Robert R

    2011-07-01

    We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior. PMID:21586818

  14. Use of thermogravimetric analysis to develop accelerated test methods to investigate long-term environmental effects on fiber-reinforced plastics

    SciTech Connect

    Prian, L.; Pollard, R.; Shan, R.; Mastropietro, C.W.; Barkatt, A. [Catholic Univ. of America, Washington, DC (United States); Gentry, T.R. [Georgia Inst. of Tech., Atlanta, GA (United States); Bank, L.C. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering

    1997-12-31

    The development of accelerated test methods to characterize long-term environmental effects on fiber-reinforced plastics (FRPs) requires the use of physicochemical methods, as well as macromechanical measurements, in order to investigate the degradation processes and predict their course over long periods of time. Thermochemical and mechanical measurements were performed on a large number of FRPs exposed to neutral, basic, and acidic media between 23 and 80 C over periods of 7 to 224 days. The resin matrices used in the present study included vinylester, polyester, and epoxy, and the fiber materials were silicate glass, aramid, and carbon. TGA was used to study the effects of aqueous media on FRPs. In particular, the relative weight loss upon heating the previously exposed material from 150 to 300 C was found to be indicative of the extent of matrix depolymerization. Indications were obtained for correlation between this weight loss and the extent of degradation of various measures of mechanical strength. The measured weight change of the tested materials during exposure was found to reflect the extent of water absorption and could be related to the extent of the weight loss between 150 and 300 C. In basic environments, weight loss, rather than gain, took place as a result of fiber dissolution.

  15. Accelerated relative sea-level rise and rapid coastal erosion: Testing a causal relationship for the Louisiana barrier islands

    USGS Publications Warehouse

    List, J.H.; Sallenger, A.H., Jr.; Hansen, M.E.; Jaffe, B.E.

    1997-01-01

    The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline west of the Mississippi delta are derived from bathymetric surveys conducted during the 1880s. 1930s and 1980s. An RMS difference criterion is employed to test whether an equilibrium profile form is maintained between survey years. Only about half the studied profiles meet the equilibrium Criterion this represents a significant limitation on the potential applicability of the Bruun rule. The profiles meeting the equilibrium criterion, along with measured rates of relative sea-level rise, are used to hindcast shoreline retreat rates at 37 locations within the study area. Modeled and observed shoreline retreat rates show no significant correlation. Thus in terms of the Bruun approach relative sea-level rise has no power for hindcasting (and presumably forecasting) rates of coastal erosion for the Louisiana barrier islands.

  16. Testing

    MedlinePLUS

    ... curesma.org > learn about sma > causes & diagnoses > testing Testing An SMA diagnosis must be confirmed through genetic ... and must be identified through further testing. Prenatal Testing Prenatal testing is used to determine if a ...

  17. 40 CFR 1065.630 - Local acceleration of gravity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Local acceleration of gravity. 1065.630 Section 1065.630 Protection...Requirements § 1065.630 Local acceleration of gravity. (a) The acceleration of Earth's gravity, a g , varies depending on the test...

  18. Wakefield accelerators

    SciTech Connect

    Simpson, J.D.

    1990-01-01

    The search for new methods to accelerate particle beams to high energy using high gradients has resulted in a number of candidate schemes. One of these, wakefield acceleration, has been the subject of considerable R D in recent years. This effort has resulted in successful proof of principle experiments and in increased understanding of many of the practical aspects of the technique. Some wakefield basics plus the status of existing and proposed experimental work is discussed, along with speculations on the future of wake field acceleration. 10 refs., 6 figs.

  19. Testing.

    ERIC Educational Resources Information Center

    Killoran, James, Ed.

    1984-01-01

    This journal issue addresses the issue of testing in the social studies classroom. The first article, "The Role of Testing" (Bragaw), focuses on the need for tests to reflect the objectives of the study completed. The varying functions of pop quizzes, weekly tests, and unit tests are explored. "Testing Thinking Processes" (Killoran, Zimmer, and…

  20. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P. (Albuquerque, NM); Devaney, Howard F. (Cedar Crest, NM); Hake, Lewis W. (Albuquerque, NM)

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  1. Trends in electron accelerator applications

    Microsoft Academic Search

    S. P Kapitza; Yu. M Tsipenyuk

    1998-01-01

    The development of electron accelerators has led over the last decades to technologies that permit to build machines of great energies and power. For energies up to 30–40 MeV research and practical applications are numerous and they are considered in some detail. Medical and radiological uses, nondestructive testing, injectors to larger accelerators, storage rings and free electron lasers are typical

  2. Photon acceleration in vacuum

    E-print Network

    J. T. Mendonca; M. Marklund; P. K. Shukla; G. Brodin

    2006-08-16

    A new process associated with the nonlinear optical properties of the electromagnetic vacuum, as predicted by quantum electrodynamics, is described. This can be called photon acceleration in vacuum, and corresponds to the frequency shift that takes place when a given test photon interacts with an intense beam of background radiation.

  3. Shock accelerated electron beams in the corona

    NASA Astrophysics Data System (ADS)

    Mann, G.; Klassen, A.

    2003-04-01

    In the solar corona shock waves can be observed as type II radio bursts in dynamic spectra of the solar radio radiation. Some of these type II bursts show sub-structures, so-called "herringbones", which are regarded as signatures of electron beams produced by the associated shock waves. A sample of solar type II radio bursts with "herringbone" - structures has been investigated with respect to their properties in dynamic radio spectra. It is well-known, that the electrons accelerated by a quasi-perpendicular shock establish a shifted loss-cone velocity distribution. The resulting properties of such a distribution for the shock accelerated electrons is compared with the features of "herringbones" in dynamic radio spectra. This study shows that the "herringbones" are mainly produced by nearly perpendicular shocks. The rapid pitch angle diffusion in the velocity space leads to a limited life time of the electron beams associated with the "herringbones".

  4. Particle Accelerators Test Cosmological Theory.

    ERIC Educational Resources Information Center

    Schramm, David N.; Steigman, Gary

    1988-01-01

    Discusses the symbiotic relationship of cosmology and elementary-particle physics. Presents a brief overview of particle physics. Explains how cosmological considerations set limits on the number of types of elementary particles. (RT)

  5. Blind Evaluation of the Microwave-Accelerated Metal-Enhanced Fluorescence Ultrarapid and Sensitive Chlamydia trachomatis Test by Use of Clinical Samples

    PubMed Central

    Melendez, Johan H.; Huppert, Jill S.; Jett-Goheen, Mary; Hesse, Elizabeth A.; Quinn, Nicole; Gaydos, Charlotte A.

    2013-01-01

    Accurate point-of-care (POC) diagnostic tests for Chlamydia trachomatis infection are urgently needed for the rapid treatment of patients. In a blind comparative study, we evaluated microwave-accelerated metal-enhanced fluorescence (MAMEF) assays for ultrafast and sensitive detection of C. trachomatis DNA from vaginal swabs. The results of two distinct MAMEF assays were compared to those of nucleic acid amplification tests (NAATs). The first assay targeted the C. trachomatis 16S rRNA gene, and the second assay targeted the C. trachomatis cryptic plasmid. Using pure C. trachomatis, the MAMEF assays detected as few as 10 inclusion-forming units/ml of C. trachomatis in less than 9 min, including DNA extraction and detection. A total of 257 dry vaginal swabs from 245 female adolescents aged 14 to 22 years were analyzed. Swabs were eluted with water, the solutions were lysed to release and to fragment genomic DNA, and MAMEF-based DNA detection was performed. The prevalence of C. trachomatis by NAATs was 17.5%. Of the 45 samples that were C. trachomatis positive and the 212 samples that were C. trachomatis negative by NAATs, 33/45 and 197/212 were correctly identified by the MAMEF assays if both assays were required to be positive (sensitivity, 73.3%; specificity, 92.9%). Using the plasmid-based assay alone, 37/45 C. trachomatis-positive and 197/212 C. trachomatis-negative samples were detected (sensitivity, 82.2%; specificity, 92.9%). Using the 16S rRNA assay alone, 34/45 C. trachomatis-positive and 197/212 C. trachomatis-negative samples were detected (sensitivity, 75.5%; specificity, 92.9%). The overall rates of agreement with NAAT results for the individual 16S rRNA and cryptic plasmid assays were 89.5% and 91.0%, respectively. Given the sensitivity, specificity, and rapid detection of the plasmid-based assay, the plasmid-based MAMEF assay appears to be suited for clinical POC testing. PMID:23804384

  6. Accelerated/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory California Institute of Technology for the encapsulation task of the low-cost solar array project

    NASA Technical Reports Server (NTRS)

    Kolyer, J. M.

    1978-01-01

    An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants, substrates, and types of circuitry. One common failure mode was corrosion of circuitry and solar cell metallization due to moisture penetration. Another was darkening and/or opacification of encapsulant. A test program plan was proposed. It includes multicondition accelerated exposure. Another method was hyperaccelerated photochemical exposure using a solar concentrator. It simulates 20 year of sunlight exposure in a short period of one to two weeks. The study was beneficial in identifying some cost effective encapsulants and array designs.

  7. Solar system constraints on Rindler acceleration

    E-print Network

    Sante Carloni; Daniel Grumiller; Florian Preis

    2011-05-09

    We discuss the classical tests of general relativity in the presence of Rindler acceleration. Among these tests the perihelion shifts give the tightest constraints and indicate that the Pioneer anomaly cannot be caused by a universal solar system Rindler acceleration. We address potential caveats for massive test-objects. Our tightest bound on Rindler acceleration that comes with no caveats is derived from radar echo delay and yields |a|<3nm/s^2.

  8. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried [Universidade Federal do Espírito Santo, Departamento de Física, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil); Hipólito-Ricaldi, Wiliam S., E-mail: win_unac@hotmail.com, E-mail: hipolito@ceunes.ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br [Universidade Federal do Espírito Santo, Departamento de Ciências Naturais, Grupo de Física Teórica, Rodovia BR 101 Norte, km 60, Campus de São Mateus, CEP 29932-540, São Mateus, Espírito Santo (Brazil)

    2012-04-01

    According to the standard ?CDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  9. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  10. Evaluation of HVDC cables for the St. Lawrence River crossing of Hydro-Quebec's 500 kV DC line. Part 2; Cable testing facility for dielectric and accelerated aging

    SciTech Connect

    Trinh, N.G.; Couderc, D.; Faucher, P.; Chaaban, M.; Belec, M.; Leduc, J. (Inst. de Recherche d'Hydro-Quebec, Varennes, Quebec J3X 1S1 (CA))

    1992-04-01

    This paper describes the new cable testing facility at IREQ for long-term accelerated aging tests on HV cables. This test facility was required as part of an extensive program to evaluate the high-voltage cables for the river crossing of Hydro-Quebec's new transmission lines rated 800 kV AC and {plus minus}500 kV DC. The first application was for the evaluation of self-contained oil-filled (SCOF) cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper also describes the specific dielectric constraints resulting from the insertion of a short length of cable into a long line and, also, the circuits developed for the special tests, which reproduce the specific cable test conditions.

  11. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  12. Electrothermal accelerators

    Microsoft Academic Search

    M. D. Driga; M. W. Ingram; W. F. Weldon

    1989-01-01

    In electrothermal (ET) guns, the projectile acceleration is governed by gas dynamics as in explosively-driven guns. In a conventional gun, however, both the energy for heating and the material to be heated are contained in the solid propellant. Electrothermal launchers allow an external electric power supply to be used to provide the necessary energy; hence, lower atomic weight propellants may

  13. Plasma accelerator

    DOEpatents

    Wang, Zhehui (Los Alamos, NM); Barnes, Cris W. (Santa Fe, NM)

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  14. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  15. Inductive Plasma Accelerator (IPA)

    NASA Astrophysics Data System (ADS)

    Ziemba, Timothy; Slough, John

    2005-10-01

    The Inductive Plasma Accelerator (IPA) is a plasma accelerator/interaction experiment currently under constuction at MSNW. The accelerator will be capable of launching a Field Reversed Configuration (FRC) plasmoid having a mass of up to 0.2 mg with a diameter no larger than about 10 cm. In addition, the accelerator will be designed to attain plasma/plasmoid velocities up to 300 km/s while maintaining high uniformity and purity. Two IPAs will be arranged on a test bed to perform FRC merging experiments. In addition, an interaction chamber will be constucted to produce and implode a plasma liner for enhanced compression experiments on the merged FRCs thus providing the first experimental test of the plasma liner fusion concept. 2D MHD simulations show expected densities of > 10^22 m-3 with ion temperatures in excess of 800 eV for the merging FRCs. The status of design and construction of the experiment and additional simulation results will be presented

  16. Inverse Free Electron Laser accelerator

    NASA Astrophysics Data System (ADS)

    Fisher, A.; Gallardo, J.; Vansteenbergen, A.; Sandweiss, J.

    1992-09-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e(-) beam and the 10(exp 11) Watt CO2 laser beam of BNL's Accelerator Test Facility (ATF), Center for Accelerator Physics (CAP) and a wiggler. The latter element is designed as a fast excitation unit making use of alternating stacks of Vanadium Permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive, nonmagnetic laminations, which act as eddy current induced field reflectors. Wiggler parameters and field distribution data will be presented for a prototype wiggler in a constant period and in a approximately 1.5 percent/cm tapered period configuration. The CO2 laser beam will be transported through the IFEL interaction region by means of a low loss, dielectric coated, rectangular waveguide. Short waveguide test sections have been constructed and have been tested using a low power CW CO2 laser. Preliminary results of guide attenuation and mode selectivity will be given, together with a discussion of the optical issues for the IFEL accelerator. The IFEL design is supported by the development and use of 1D and 3D simulation programs. The results of simulation computations, including also wiggler errors, for a single module accelerator and for a multi-module accelerator will be presented.

  17. Inverse free electron laser accelerator

    NASA Astrophysics Data System (ADS)

    Fisher, A.; Gallardo, J.; Sandweiss, J.; van Steenbergen, A.

    1992-07-01

    The study of the INVERSE FREE ELECTRON LASER, as a potential mode of electron acceleration, is being pursued at Brookhaven National Laboratory. Recent studies have focussed on the development of a low energy, high gradient, multi stage linear accelerator. The elementary ingredients for the IFEL interaction are the 50 MeV Linac e- beam and the 1011 Watt CO2 laser beam of BNL's Accelerator Test Facility (ATF), Center for Accelerator Physics (CAP), and a wiggler. The latter element is designed as a fast excitation unit making use of alternating stacks of Vanadium Permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive, nonmagnetic laminations, which act as eddy current induced field reflectors. Wiggler parameters and field distribution data will be presented for a prototype wiggler in a constant period and in a ?1.5%/cm tapered period configuration. The CO2 laser beam will be transported through the IFEL interaction region by means of a low loss, dielectric coated, rectangular waveguide. Short waveguide test sections have been constructed and have been tested using a low power cw CO2 laser. Preliminary results of guide attenuation and mode selectivity will be given, together with a discussion of the optical issues for the IFEL accelerator. The IFEL design is supported by the development and use of 1D and 3D simulation programs. The results of simulation computations, including also wiggler errors, for a single module accelerator and for a multi-module accelerator will be presented.

  18. U. S. -French Cooperative Research Program: U. S. test results for cable insulation and jacket materials at the completion of accelerated aging

    SciTech Connect

    Bustard, L.D.

    1984-01-01

    Eight different U.S. insulation and jacket products have been accelerated aged at Sandia. The experimental variables included: (1) sequential versus simultaneous accelerated aging exposures; (2) the order of the sequential exposures; and (3) ambient versus 70/sup 0/C irradiation temperatures during sequential aging exposures. We observed that the irradiation temperature (70/sup 0/C or ambient) was secondary in importance to the choice of sequence for thermal and radiation aging. For most materials studied (except TEFZEL) the irradiation then thermal aging sequence was as severe or more severe than the thermal then irradiation aging sequence.

  19. BICEP's acceleration

    E-print Network

    Carlo R. Contaldi

    2014-07-24

    The recent BICEP2 detection of, what is claimed to be primordial $B$-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential $V(\\phi)$ for the first time - if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles $\\epsilon(N)$ as a function of $e$-fold $N$ and derived posterior distributions of the primordial power spectrum $P(k)$ and potential $V(\\phi)$. We find that the BICEP2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales $k\\sim 10^{-3}$ Mpc$^{-1}$. This is in agreement with a previous detection of a suppression in the scalar power.

  20. Investigation of accelerated thermal aging of EPDM polymer by electric tests in air and by means of a SEM technique in high vacuum

    Microsoft Academic Search

    D. Bouguedad; O. Jbara; S. Rondot; A. Mekhaldi; A. Hadjadj

    2012-01-01

    In the current work we will concentrate on the study of thermal accelerated ageing process. A specific example focuses on the degradation of Ethylene Propylene Diene Monomer (EPDM). The reference material and the aged specimens were characterized by electrical methods performed in air and by a method developed in vacuum of a scanning electron microscope (SEM). A temperature of 90°

  1. Accelerator Technology Division progress report, FY 1993

    SciTech Connect

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-12-31

    This report discusses the following topics: A Next-Generation Spallation-Neutron Source; Accelerator Performance Demonstration Facility; APEX Free-Electron Laser Project; The Ground Test Accelerator (GTA) Program; Intense Neutron Source for Materials Testing; Linac Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Radio-Frequency Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operation.

  2. An inverse free-electron-laser accelerator

    Microsoft Academic Search

    A. S. Fisher; J. C. Gallardo; A. van Steenbergen; S. Ulc; M. Woodle; J. Sandweiss; Jyan-Min Fang

    1993-01-01

    Recent work at BNL on electron acceleration using the Inverse Free-Electron Laser (IFEL) has considered a low-energy, high-gradient, multi-stage linear accelerator. Experiments are planned at BNL's Accelerator Test Facility using its 50-MeV linac and 100-GW CO2 laser. We have built and tested a fast-excitation wiggler magnet with constant field, tapered period, and overall length of 47 cm. Vanadium-Permendur ferromagnetic laminations

  3. Electrodynamics of accelerated systems

    NASA Astrophysics Data System (ADS)

    Hauck, John Christian

    The standard theory for accelerated observers relies on the premise that measurements can be made instantaneously or, equivalently, over a time interval where the change in the observer's velocity is negligible i.e. the hypothesis of locality. This theory provides good agreement with experiment for most cases. However, for very large accelerations this local theory should diverge from experimental results. This work considers measurements of frequency where the velocity of the observer appreciably changes during the time of the measurement. This is done through a numerical Fourier analysis of a pulse of electromagnetic radiation. When this is done, the frequency spectra seen by these accelerated observers have a much more complex structure than under the standard theory. Also, in this work, the phenomenon of helicity-rotation coupling is considered and some of the observation consequences of the coupling of the spin of the particle with the rotation of a gravitational source will be examined. Although at present most experiments can not produce accelerations large enough to diverge from the standard theory, recent advances in laser technology, such as Chirped Pulse Amplification, may soon allow the non-standard theory to be tested. It is in expectation of this that this work has been done.

  4. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  5. Direct and Accelerated Characterization of Formulation Stability

    Microsoft Academic Search

    D. Lerche; T. Sobisch

    2011-01-01

    Formulation of products as well as process and quality control is in need of fast and efficient measurement techniques of the state of dispersion products. We review the basics of experimental techniques of stability assessment of suspensions and emulsions, procedures of accelerated stability testing, and discuss the relationship between results of “acceleratedtests and the outcome under normal conditions of

  6. Trends in electron accelerator applications

    Microsoft Academic Search

    S. P. Kapitza; Yu. M. Tsipenyuk

    1998-01-01

    The development of electron accelerators has led over the last decades to technologies that permit to build machines of great energies and power. For energies up to 30-40MeV research and practical applications are numerous and they are considered in some detail. Medical and radiological uses, nondestructive testing, injectors to larger accelerators, storage rings and free electron lasers are typical for

  7. Acceleration using total internal reflection

    SciTech Connect

    Fernow, R.C.

    1991-06-07

    This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.

  8. Presented at the Tenth European Particle Accelerator Conference, Edinburgh, Scotland, June 2006 ERL06-3 HIGH POWER TESTING RF SYSTEM COMPONENTS FOR THE

    E-print Network

    subsequent high-potting. The 20 kWCW AFT ferrite circulator (Figure 4) was tested up to 16 kW in traveling06-3 HIGH POWER TESTING RF SYSTEM COMPONENTS FOR THE CORNELL ERL INJECTOR* S. Belomestnykh# , R for testing/processing the input couplers. The results of the first high-power tests are presented. 1

  9. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  10. Impact of flavour solvent (propylene glycol or triacetin) on vanillin, 5-(hydroxymethyl)furfural, 2,4-decadienal, 2,4-heptadienal, structural parameters and sensory perception of shortcake biscuits over accelerated shelf life testing.

    PubMed

    Yang, Ni; Hort, Joanne; Linforth, Robert; Brown, Keith; Walsh, Stuart; Fisk, Ian D

    2013-11-15

    The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was investigated during accelerated shelf life (ASL) testing of shortcake biscuits. Specifically, the differential effect on the stability of added vanillin, the natural baked marker compound 5-(hydroxymethyl)furfural (HMF), specific markers of oxidative rancidity (2,4-decadienal, 2,4-heptadienal), and the structural parameters of hardness and fracturability. Significantly more HMF was formed during baking of biscuits prepared with TA; these biscuits were also more stable to oxidative degradation and loss of vanillin during ageing than biscuits prepared with PG. Fresh TA biscuits were significantly more brittle than fresh PG biscuits. There was no impact of solvent choice on hardness. Sensory evaluation of hardness, vanilla flavour and oily off-note was tested during ASL testing. There was no significant impact of storage on sensory ratings for either the PG or TA biscuits. PMID:23790924

  11. Final report on accelerated\\/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory, California Institute of Technology for the Encapsulation Task of the Low-Cost Solar Array Project. Period covered: October 25, 1977April 30, 1978

    Microsoft Academic Search

    J. M. Kolyer; N. R. Mann; J. Farrar

    1978-01-01

    Accelerated and abbreviated test methods were developed for predicting the outdoor lifetime of solar cell encapsulants. Encapsulants are clear materials applied as covers to protect the cells from environmental hazards. An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants,

  12. Converting an AEG Cyclotron to H? Acceleration and Extraction

    NASA Astrophysics Data System (ADS)

    Ramsey, Fred; Carroll, Lewis; Rathmann, Tom; Huenges, Ernst; Bechtold, Matthias Mentler Volker

    2009-03-01

    Clinical Trials are under way to evaluate agents labeled with the nuclide 225Ac and its decay product 213Bi, in targeted alpha-immuno-therapy [1]. 225Ac can be produced on a medium-energy cyclotron via the nuclear reaction 226Ra(p,n)225Ac. To demonstrate proof-of-principle, a vintage AEG cyclotron, Model E33 [2], with an internal target, had been employed in a pilot production program at the Technical University of Munich (TUM). To enhance production capability and further support the clinical studies, the TUM facility has recently been refurbished and upgraded, adding a new external beam-line, automated target irradiation and transport systems, new laboratories, hot cells, etc. [3]. An improved high-power rotating target has been built and installed [4]. The AEG cyclotron itself has also been modified and upgraded to accelerate and extract H? ions. We have designed, built, and tested a new axial Penning-type ion source which is optimized for the production of H? ions. The ion source has continued to evolve through experiment and experience. Steady improvements in materials and mechanics have led to enhanced source stability, life-time, and H? production. We have also designed and built a precision H? charge-exchange beam-extraction system which is equipped with a vacuum lock. To fit within the tight mechanical constraint imposed by the narrow magnet gap, the system incorporates a novel chain-drive foil holder and foil-changer mechanism. The reconfigured cyclotron system has now been in operation for more than 1 year. Three long-duration target irradiations have been conducted. The most recent bombardment ran 160 continuous hours at a beam on target of ˜80 microamperes for a total yield of ˜70 milli-curies of 225Ac.

  13. High Power Beam Test and Measurement of Emittance Evolution of a 1.6-Cell Photocathode RF Gun at Pohang Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Park, Jang-Ho; Park, Sung-Ju; Kim, Changbum; Parc, Yong-Woon; Hong, Ju-Ho; Huang, Jung-Yun; Xiang, Dao; Wang, Xijie; Ko, In Soo

    2007-04-01

    A Brookhaven National Laboratory (BNL) GUN-IV type photocathode rf gun has been fabricated to use in femtosecond electron diffraction (FED), femtosecond far infrared radiation (fs-FIR) facility, and X-ray free electron laser (XFEL) facilities at the Pohang Accelerator Laboratory (PAL). The gun consists of a 1.6-cell cavity with a copper cathode, a solenoid magnet, beam diagnostic components and auxiliary systems. We report here the measurement of the basic beam parameters which confirm a successful fabrication of the photocathode RF gun system. The emittance evolution is measured by an emittance meter and compared with the PARMELA simulation, which shows a good agreement.

  14. FERMI ACCELERATION. DMITRY DOLGOPYAT

    E-print Network

    Dolgopyat, Dmitry

    FERMI ACCELERATION. DMITRY DOLGOPYAT Abstract. Fermi acceleration is a mechanism, first suggested, on average, be accelerated. Since then Fermi acceleration has been used to explain a number of natural phenomena and sev- eral simple mathematical models demonstrating Fermi acceleration have been proposed. We

  15. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  16. Development and testing of a deuterium gas target assembly for neutron production via the H-2(d,n)He-3 reaction at a low-energy accelerator facility

    SciTech Connect

    Feautrier, D.; Smith, D.L.

    1992-03-01

    This report describes the development and testing of a deuterium gas target intended for use at a low-energy accelerator facility to produce neutrons for basic research and various nuclear applications. The principle source reaction is H-2(d,n)He-3. It produces a nearly mono-energetic group of neutrons. However, a lower-energy continuum neutron spectrum is produced by the H-2(d;n,p)H-2 reaction and also by deuterons which strike various components in the target assembly. The present target is designed to achieve the following objectives: (1) minimize unwanted background neutron production from the target assembly, (2) provide a relatively low level of residual long-term activity within the target components, (3) have the capacity to dissipate up to 150 watts of beam power with good target longevity, and (4) possess a relatively modest target mass in order to minimize neutron scattering from the target components. The basic physical principles that have to be considered in designing an accelerator target are discussed and the major engineering features of this particular target design are outlined. The results of initial performance tests on this target are documented and some conclusions concerning the viability of the target design are presented.

  17. Nonlocality of Accelerated Systems

    E-print Network

    Bahram Mashhoon

    2003-05-11

    The conceptual basis for the nonlocality of accelerated systems is presented. The nonlocal theory of accelerated observers and its consequences are briefly described. Nonlocal field equations are developed for the case of the electrodynamics of linearly accelerated systems.

  18. Ion Induction Accelerators

    Microsoft Academic Search

    John J. Barnard; Kazuhiko Horioka

    2011-01-01

    \\u000a The description of beams in RF and induction accelerators share many common features. Likewise, there is considerable commonality\\u000a between electron induction accelerators (see Chap. 7) and ion induction accelerators. However, in contrast to electron induction\\u000a accelerators, there are fewer ion induction accelerators that have been operated as application-driven user facilities. Ion\\u000a induction accelerators are envisioned for applications (see Chap. 10)

  19. Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid).

    PubMed

    Fairchild, James F; Allert, Ann; Sappington, Linda S; Nelson, Karen J; Valle, Janet

    2008-03-01

    We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration:time data matrix. PMID:17975948

  20. Accelerated test methods for predicting the life of motor materials exposed to refrigerant/lubricant mixtures. Phase 1, Conceptual design: Final report

    SciTech Connect

    Ellis, P.F. II; Ferguson, A.

    1993-08-18

    The federally mandated phase-out of chlorofluorocarbon refrigerants requires screening tests for motor materials compatibility with alternative refrigerant/lubricant mixtures. In the current phase of the program, ARTI is supporting tests of promising candidate refrigeration/lubricant systems in key refrigeration component systems such as bearings and hermetic motor insulation systems to screen for more subtle detrimental effects and allow estimates of motor-compressor life. This report covers: mechanisms of failure of hermetic motor insulation, current methods for estimation of life of hermetic motors, and conceptual design of improved stator simulator device for testing of alternative refrigerant/lubricant mixtures.

  1. Simulating ion beam extraction from a single aperture triode acceleration column: A comparison of the beam transport codes IGUN and PBGUNS with test stand data

    SciTech Connect

    Patel, A.; Wills, J. S. C.; Diamond, W. T. [Chalk River Laboratories, AECL, Chalk River, Ontario K0 J 1J0 (Canada)

    2008-04-15

    Ion beam extraction from two different ion sources with single aperture triode extraction columns was simulated with the particle beam transport codes PBGUNS and IGUN. For each ion source, the simulation results are compared to experimental data generated on well-equipped test stands. Both codes reproduced the qualitative behavior of the extracted ion beams to incremental and scaled changes to the extraction electrode geometry observed on the test stands. Numerical values of optimum beam currents and beam emittance generated by the simulations also agree well with test stand data.

  2. Accelerator validation of an FPGA SEU simulator

    Microsoft Academic Search

    Eric Johnson; Michael Caffrey; Paul Graham; Nathan Rollins; Michael Wirthlin

    2003-01-01

    An accelerator test was used to validate the performance of an FPGA single event upset (SEU) simulator. The Crocker Nuclear Laboratory cyclotron proton accelerator was used to irradiate the SLAAC1-V, a Xilinx Virtex FPGA board. We also used the SLAAC1-V as the platform for a configuration bitstream SEU simulator. The simulator was used to probe the \\

  3. Parameters of a pulsed plasma accelerator torch

    Microsoft Academic Search

    S. I. Griniuk; V. I. Lisichenko; N. L. Sokolova

    1975-01-01

    Results of an investigation of plasma streams generated by a pulsed plasma accelerator actuated by electrical explosion of thin-wire conductors are reported. Al, Fe, and W conductors were tested. Plasma bunches accelerated were examined by means of ultrahigh-speed photography, spectroscopy, calorimetry, and a ballistic pendulum. The dynamics, velocity characteristics, and energy contents of the bunches were studied, and estimates of

  4. Accelerated Reader. What Works Clearinghouse Intervention Report

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2009

    2009-01-01

    "Accelerated Reader" is a computer-based reading management system designed to complement an existing classroom literacy program for grades pre-K-12. It is designed to increase the amount of time students spend reading independently. Students choose reading-level appropriate books or short stories for which Accelerated Reader tests are available…

  5. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    PubMed

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (?=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors. PMID:24387907

  6. Effect of alloy type on the life-time of torsion-preloaded nickel-titanium endodontic instruments.

    PubMed

    Ha, Jung-Hong; Kim, Sung Kyo; Cheung, Gary Shun-Pan; Jeong, Seong Hwa; Bae, Yong Chul; Kim, Hyeon-Cheol

    2015-05-01

    This study was aimed to evaluate the effect of torsional preloads on the cyclic fatigue life of nickel-titanium (NiTi) instruments with different history of heat treatments by manufacturers. WaveOne (Primary) made of M-wire, K3XF (#30/0.06) of R-phase, and ProTaper (F2) of conventional NiTi alloy was used. Each file was preloaded at four conditions (nil, 25, 50, and 75% of their mean ultimate torsional strength) before fatigue testing. The torsional preloads 10-, 30-, or 50-times were applied by securing 5?mm of the file tip, rotating it until the preset torque was attained before returning to the origin. Then, the number of cycles to failure (NCF) was evaluated by rotational bending in a simulated canal. Data were analyzed using multiple linear regression analysis and two-way ANOVA. Fractured instruments were examined under scanning electron microscope (SEM). SEM showed that most WaveOne after 75% preloading, regardless of repetitions, showed some longitudinal cracks parallel to the long axis of the file, which were rare for K3XF. Regression analysis revealed that the brand of instrument was the most critical factor. At up to 75% preloading, ProTaper and K3XF did not show any significant decline in NCF. For 30-repetition groups of WaveOne, the 50 and 25% torsion preloaded groups showed a significantly higher NCF than the 0 and 75% groups. Within the limitations of this study, the alloy type of NiTi instrument have a significant effect on the phenomenon that a certain amount of torsional preload may improve the cyclic fatigue resistance of NiTi rotary instruments. SCANNING 37:172-178, 2015. © 2015 Wiley Periodicals, Inc. PMID:25676195

  7. Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing

    NASA Technical Reports Server (NTRS)

    Bamberger, Helmut H.; Robinson, R. Craig; Jurns, John M.; Grasl, Steven J.

    2011-01-01

    Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions.

  8. Covariant Uniform Acceleration

    E-print Network

    Yaakov Friedman; Tzvi Scarr

    2013-04-29

    We show that standard Relativistic Dynamics Equation F=dp/d\\tau is only partially covariant. To achieve full Lorentz covariance, we replace the four-force F by a rank 2 antisymmetric tensor acting on the four-velocity. By taking this tensor to be constant, we obtain a covariant definition of uniformly accelerated motion. We compute explicit solutions for uniformly accelerated motion which are divided into four types: null, linear, rotational, and general. For null acceleration, the worldline is cubic in the time. Linear acceleration covariantly extends 1D hyperbolic motion, while rotational acceleration covariantly extends pure rotational motion. We use Generalized Fermi-Walker transport to construct a uniformly accelerated family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the Weak Hypothesis of Locality, we obtain local spacetime transformations from a uniformly accelerated frame K' to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. We obtain velocity and acceleration transformations from a uniformly accelerated system K' to an inertial frame K. We derive the general formula for the time dilation between accelerated clocks. We obtain a formula for the angular velocity of a uniformly accelerated object. Every rest point of K' is uniformly accelerated, and its acceleration is a function of the observer's acceleration and its position. We obtain an interpretation of the Lorentz-Abraham-Dirac equation as an acceleration transformation from K' to K.

  9. I. ACCELERATION A. Introduction

    E-print Network

    McDonald, Kirk

    I. ACCELERATION A. Introduction Following cooling and initial bunch compression, the beams must be rapidly accelerated. The acceleration needed for a Higgs collider is probably the most conventional part undertaken. A sequence of linacs would work, but would be expensive. Some form of circulating acceleration

  10. Future accelerator technology

    SciTech Connect

    Sessler, A.M.

    1986-05-01

    A general discussion is presented of the acceleration of particles. Upon this foundation is built a categorization scheme into which all accelerators can be placed. Special attention is devoted to accelerators which employ a wake-field mechanism and a restricting theorem is examined. It is shown how the theorem may be circumvented. Comments are made on various acceleration schemes.

  11. EXPONENTIATED LOG-LOGISTIC DISTRIBUTION - AN ECONOMIC RELIABILITY TEST PLAN

    Microsoft Academic Search

    K. Rosaiah; R. R. L. Kantam; Santosh Kumar

    2007-01-01

    The exponentiated log-logistic distribution introduced by Rosaiah et al (2006) is considered as a probability model for the life time of the product. Sampling plans in which items that are put to test, to collect the life of the items in order to decide upon accepting or rejecting a submitted lot, are called reliability test plans. A test plan to

  12. Plasma wakefield acceleration experiments at FACET

    NASA Astrophysics Data System (ADS)

    Hogan, M. J.; Raubenheimer, T. O.; Seryi, A.; Muggli, P.; Katsouleas, T.; Huang, C.; Lu, W.; An, W.; Marsh, K. A.; Mori, W. B.; Clayton, C. E.; Joshi, C.

    2010-05-01

    FACET—Facilities for Accelerator science and Experimental Test beams at SLAC—will provide high-energy-density electron and positron beams with peak currents of roughly 20 kA that will be focused down to a 10 ?m×10 ?m transverse spot size at an energy of ~23 GeV. With FACET, the SLAC linac will support a unique program concentrating on second-generation research in plasma wakefield acceleration. Topics include high-gradient electron acceleration with a narrow energy spread and preserved emittance, beam loading and high-gradient positron acceleration. This paper describes the FACET facility, summarizes the state of the art for plasma wakefield accelerators and discusses the plasma wakefield accelerator program to be conducted at FACET over the next five years.

  13. Technology of magnetically driven accelerators

    SciTech Connect

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-03-26

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability. 8 figs., 1 tab.

  14. HORIZON: Accelerated General Relativistic Magnetohydrodynamics

    E-print Network

    Burkhard Zink

    2011-02-25

    We present Horizon, a new graphics processing unit (GPU)-accelerated code to solve the equations of general relativistic magnetohydrodynamics in a given spacetime. We evaluate the code in several test cases, including magnetized Riemann problems and rapidly rotating neutron stars, and measure the performance benefits of the GPU acceleration in comparison to our CPU-based code Thor. We find substantial performance gains in comparison to a quad-core CPU both in single- and double-precision accuracy, and discuss these findings in the context of future numerical modeling efforts.

  15. On the Extrapolation of Accelerated Stress Conditions to Normal Stress Conditions of Germanium Transistors

    Microsoft Academic Search

    Jayne Partridge

    1963-01-01

    ACCELERATED stressing has become a popular method of evaluating high reliability devices in short periods of testing time. However, the convenience of accelerated testing should not be the prime factor for use. Tl he modes of failure generated by normal (within rating) and accelerated (exceeding rating) stressing should be compared before failure rates created bv accelerated stressing are accepted as

  16. Acceleration without Horizons

    E-print Network

    Alaric Doria; Gerardo Munoz

    2015-02-18

    We derive the metric of an accelerating observer moving with non-constant proper acceleration in flat spacetime. With the exception of a limiting case representing a Rindler observer, there are no horizons. In our solution, observers can accelerate to any desired terminal speed $v_{\\infty} accelerating observer is completely determined by the distance of closest approach and terminal velocity or, equivalently, by an acceleration parameter and terminal velocity.

  17. Lead free interfacial structures and their relationship to Au plating including accelerated thermal cycle testing of non-leaden BGA spheres

    Microsoft Academic Search

    Toshihiko Taguchi; Rikiya Kato; Satoru Akita; Atsushi Okuno; H. Suzuki; T. Okuno

    2001-01-01

    As lead is a harmful element, soldering in the electronics industry has moved toward elimination of lead from the solder alloy. Already there are a group of companies who have begun implementation of lead-free solder alloys. The scope of parts being tested for lead-free processes is not limited to the solder material; the complete absence of lead from electronics parts,

  18. Accelerated\\/abbreviated test methods, study 4 of task 3 (encapsulation) of the Low-Cose Silicon Solar Array Project. First quarterly progress report, April--June 1976

    Microsoft Academic Search

    Kolyer

    1976-01-01

    This study is part of the ERDA-funded Low-Cost Silicon Solar Array (LSSA) Project. The objective is to develop a statistical model and test methodology to allow the prediction of encapsulant performance during a 20-year outdoor exposure. The approach is to first evaluate preliminary models by fitting literature data to them, then verify a predictive model of general applicability by means

  19. Acceleration versus heart rate for estimating energy expenditure and speed during locomotion in animals: Tests with an easy model species, Homo sapiens

    Microsoft Academic Search

    Lewis G. Halsey; Emily L. C. Shepard; Carl J. Hulston; Michelle C. Venables; Craig R. White; Asker E. Jeukendrup; Rory P. Wilson

    2008-01-01

    An important element in the measurement of energy budgets of free-living animals is the estimation of energy costs during locomotion. Using humans as a particularly tractable model species, we conducted treadmill experiments to test the validity of tri-axial accelerometry loggers, designed for use with animals in the field, to estimate rate of oxygen consumption (V?O2: an indirect measure of metabolic

  20. TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

    SciTech Connect

    Jay L. Hirshfield

    2012-05-30

    Experimental results are reported for test beam acceleration and deflection in a two-channel, cm-scale, rectangular dielectric-lined wakefield accelerator structure energized by a 14-MeV drive beam. The dominant waveguide mode of the structure is at {approx}30 GHz, and the structure is configured to exhibit a high transformer ratio ({approx}12:1). Accelerated bunches in the narrow secondary channel of the structure are continuously energized via Cherenkov radiation that is emitted by a drive bunch moving in the wider primary channel. Observed energy gains and losses, transverse deflections, and changes in the test bunch charge distribution compare favorably with predictions of theory.

  1. CENTRIPETAL ACCELERATION AND CENTRIFUGAL FORCE IN GENERAL RELATIVITY

    E-print Network

    Jantzen, Robert T.

    1 CENTRIPETAL ACCELERATION AND CENTRIFUGAL FORCE IN GENERAL RELATIVITY D. BINI Istituto per mechanics non-inertial observers studying accelerated test particle motion experience a centripetal acceleration which, once interpreted as a centrifugal force acting on the particle, allows writing the particle

  2. Modeling students' conceptual understanding of force, velocity, and acceleration

    E-print Network

    Zollman, Dean

    Modeling students' conceptual understanding of force, velocity, and acceleration Rebecca Rosenblatt, velocity, and acceleration. The test was administered to more than 800 students enrolled in standard incorrect response that velocity must be in the direction of the acceleration or net force, up to 30

  3. Minimum accelerations from quantised inertia

    E-print Network

    McCulloch, M E

    2010-01-01

    It has recently been observed that there are no disc galaxies with masses less than 10^9 M_solar and this cutoff has not been explained. It is shown here that this minimum mass can be predicted using a model that assumes that 1) inertia is due to Unruh radiation, and 2) this radiation is subject to a Hubble-scale Casimir effect. The model predicts that as the acceleration of an object decreases, its inertial mass eventually decreases even faster stabilising the acceleration at a minimum value, which is close to the observed cosmic acceleration. When applied to rotating disc galaxies the same model predicts that they have a minimum rotational acceleration, ie: a minimum apparent mass of 1.1x10^9 M_solar, close to the observed minimum mass. The Hubble mass can also be predicted. It is suggested that assumption 1 above could be tested using a cyclotron to accelerate particles until the Unruh radiation they see is short enough to be supplemented by manmade radiation. The increase in inertia may be detectable.

  4. Design and testing of a high power, ultra-high vacuum, dual-directional coupler for the Advanced Photon Source (APS) linear accelerator

    SciTech Connect

    Brauer, S.O.; Grelick, A.E.; Grimmer, J.; Otocki, R.D.; Kang, Y.W.; Noonan, J.; Russell, T.

    1995-07-01

    Leaks and cracks have developed in the vacuum windows of the linac WR 284 waveguide directional couplers. In the existing coupler design the vacuum window is brazed to the waveguide. Replacement of a cracked window requires the removal of the component from the waveguide system resulting in a loss of vacuum in the waveguide. A new design has been developed and a prototype tested that utilizes bolted-in vacuum windows and allows for easier replacement of the windows in the system, while still providing suitable radio frequency (rf) specifications.

  5. TURBULENT SHEAR ACCELERATION

    SciTech Connect

    Ohira, Yutaka, E-mail: ohira@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258 (Japan)

    2013-04-10

    We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

  6. Modifications of the 85\\/85 test and the temperature cycling test for tantalum capacitors

    Microsoft Academic Search

    Johanna Virkki; Lauri Sydänheimo; Pasi Raumonen

    2011-01-01

    Purpose – Accelerated tests are commonly used to evaluate the reliability of electronic components and to detect failures caused by environmental conditions in field use. Many standard accelerated tests are available for evaluating the reliability in a commonly approved way. These tests form a good basis for reliability testing. However, sometimes standard accelerated tests may not be directly used to

  7. Acceleration of colliding shells around a black hole: Validity of the test particle approximation in the Banados-Silk-West process

    E-print Network

    Masashi Kimura; Ken-ichi Nakao; Hideyuki Tagoshi

    2011-02-05

    Recently, Banados, Silk and West (BSW) showed that the total energy of two colliding test particles has no upper limit in their center of mass frame in the neighborhood of an extreme Kerr black hole, even if these particles were at rest at infinity in the infinite past. We call this mechanism the BSW mechanism or BSW process. The large energy of such particles would generate strong gravity, although this has not been taken into account in the BSW analysis. A similar mechanism is seen in the collision of two spherical test shells in the neighborhood of an extreme Reissner-Nordstr\\"om black hole. In this paper, in order to draw some implications concerning the effects of gravity generated by colliding particles in the BSW process, we study a collision of two spherical dust shells, since their gravity can be exactly treated. We show that the energy of two colliding shells in the center of mass frame observable from infinity has an upper limit due to their own gravity. Our result suggests that an upper limit also exists for the total energy of colliding particles in the center of mass frame in the observable domain in the BSW process due the gravity of the particles.

  8. Acceleration of colliding shells around a black hole: Validity of the test particle approximation in the Banados-Silk-West process

    SciTech Connect

    Kimura, Masashi; Nakao, Ken-ichi [Department of Mathematics and Physics, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Tagoshi, Hideyuki [Department of Earth and Space Science, Graduate School of Science, Osaka University, Osaka 560-0043 (Japan)

    2011-02-15

    Recently, Banados, Silk and West (BSW) showed that the total energy of two colliding test particles has no upper limit in their center of mass frame in the neighborhood of an extreme Kerr black hole, even if these particles were at rest at infinity in the infinite past. We call this mechanism the BSW mechanism or BSW process. The large energy of such particles would generate strong gravity, although this has not been taken into account in the BSW analysis. A similar mechanism is seen in the collision of two spherical test shells in the neighborhood of an extreme Reissner-Nordstroem black hole. In this paper, in order to draw some implications concerning the effects of gravity generated by colliding particles in the BSW process, we study a collision of two spherical dust shells, since their gravity can be exactly treated. We show that the energy of two colliding shells in the center of mass frame observable from infinity has an upper limit due to their own gravity. Our result suggests that an upper limit also exists for the total energy of colliding particles in the center of mass frame in the observable domain in the BSW process due the gravity of the particles.

  9. The Two-beam accelerator

    SciTech Connect

    Sessler, A.M.; Hopkins, D.B.

    1986-06-01

    The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field, induction accelerator units are placed periodically along the length of the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have a serious option for a 1 TeV x 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). Description is given of a first test at ELF with a seven-cell 2..pi../3 mode structure which without preconditioning and with a not-very-good vacuum nevertheless at 35 GHz yielded an average accelerating gradient of 180 MV/m.

  10. The Use of a Vehicle Acceleration Exposure Limit Model and a Finite Element Crash Test Dummy Model to Evaluate the Risk of Injuries During Orion Crew Module Landings

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Fasanella, Edwin L.; Tabiei, Ala; Brinkley, James W.; Shemwell, David M.

    2008-01-01

    A review of astronaut whole body impact tolerance is discussed for land or water landings of the next generation manned space capsule named Orion. LS-DYNA simulations of Orion capsule landings are performed to produce a low, moderate, and high probability of injury. The paper evaluates finite element (FE) seat and occupant simulations for assessing injury risk for the Orion crew and compares these simulations to whole body injury models commonly referred to as the Brinkley criteria. The FE seat and crash dummy models allow for varying the occupant restraint systems, cushion materials, side constraints, flailing of limbs, and detailed seat/occupant interactions to minimize landing injuries to the crew. The FE crash test dummies used in conjunction with the Brinkley criteria provides a useful set of tools for predicting potential crew injuries during vehicle landings.

  11. Linear Accelerator (LINAC)

    MedlinePLUS

    ... equipment? How is safety ensured? What is this equipment used for? A linear accelerator (LINAC) is the ... pg=stereotactic) . top of page How does the equipment work? View larger with caption The linear accelerator ...

  12. Acceleration of Gravity 1

    NSDL National Science Digital Library

    Michael Horton

    2009-05-30

    This lab is a Level 2 inquiry activity that should be taught after students understand acceleration but before they learn the equations for calculating the acceleration of a body dropped from a certain height. After this activity, students should understa

  13. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  14. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  15. High Brightness Test Stand

    SciTech Connect

    Birx, D.L.; Caporaso, G.J.; Boyd, J.K.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Rogers, D. Jr.; Smith, M.W.

    1985-08-07

    The High Brightness Test Stand is a 2 MeV, less than or equal to 10 kA electron accelerator module. This accelerator module, designed as an upgrade prototype for the Advanced Test Accelerator (ATA), combines solid state nonlinear magnetic drives with state-of-the-art induction linac technology. The facility serves a dual role, as it not only provides a test bed for this new technology, but is used to develop high brightness electron optics. We will both further describe the accelerator, as well as present some of the preliminary electron optics measurements.

  16. Force, mass and acceleration

    Microsoft Academic Search

    Phil Dalrymple; Richard Griffiths

    2005-01-01

    Force, mass and acceleration are everyday words but often used inaccurately. Force is a physical influence, which when applied to an object causes it to accelerate in the direction from which it was applied. Mass is the amount of matter in an object and is expressed in kilograms. Acceleration is the rate of change of velocity of an object in

  17. Multistage induction mass accelerator

    Microsoft Academic Search

    T. J. Burgess; M. Cowan

    1984-01-01

    The present investigation has the objective to discuss considerations which define the design and performance of a multistage, coaxial induction mass accelerator operating at high magnetic energy density. A review is presented of the magnetohydrodynamic computational model required to design, in detail, a high energy density, coaxial, magnetic induction mass accelerator. Attention is given to the derivation of the accelerator

  18. Direction of Acceleration

    NSDL National Science Digital Library

    Mary Spaulding, Clearbrook-Gonvick Public School, Clearbrook Minnesota, based on an original activity from Physics Principles and Problems (1995) page 75.

    In this short lab, students observe the movement of an air bubble in a small level, attached to a toy truck, as it is moved from a stop, to a steady speed and back to a stop. This gives a visual to the concepts positive acceleration, zero acceleration and negative acceleration.

  19. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  20. Acceleration-Induced Nonlocality

    E-print Network

    Bahram Mashhoon

    2003-01-17

    The standard relativistic theory of accelerated reference frames in Minkowski spacetime is described. The measurements of accelerated observers are considered and the limitations of the standard theory, based on the hypothesis of locality, are pointed out. The physical principles of the nonlocal theory of accelerated observers are presented. The implications of the nonlocal theory are briefly discussed.

  1. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  2. Accelerated Laser Ageing Of Plastics

    NASA Astrophysics Data System (ADS)

    Snowdon, Kenneth G.; Rolt, Stephen

    1989-04-01

    Novel polymer ageing treatments based on 276 nm and 308 nm excimer laser radiation are reported. Comparison of laser ageing with natural and conventional artificial ageing (weatherometer) treatments has begun. Preliminary results indicate that the laser treatments offer increased acceleration factors 3200:1 to 120,000:1 over natural ageing and 50:1 to 3500:1 over weatherometers. Thus the laser treatments offer the prospect of reducing testing times from several months to a few tens of minutes.

  3. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  4. Entanglement of Accelerating Particles

    E-print Network

    W. L. Ku; M. -C. Chu

    2007-09-03

    We study how the entanglement of a maximally entangled pair of particles is affected when one or both of the pair are uniformly accelerated, while the detector remains in an inertial frame. We find that the entanglement is unchanged if all degrees of freedom are considered. However, particle pairs are produced, and the entanglements of different bipartite systems may change with the acceleration. In particular, the entanglement between accelerating fermions is transferred preferentially to the produced antiparticles when the acceleration is large, and the entanglement transfer is complete when the acceleration approaches infinity. However, for scalar particles, no entanglement transfer to the antiparticles is observed.

  5. Accelerations in Flight

    NASA Technical Reports Server (NTRS)

    Doolittle, J H

    1925-01-01

    This work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.

  6. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM); Young, Lloyd M. (Los Alamos, NM)

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  7. Relativistic electron acceleration by oblique whistler waves

    SciTech Connect

    Yoon, Peter H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States) [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Pandey, Vinay S. [National Institute of Technology Delhi, Dwarka, Delhi—110077 (India)] [National Institute of Technology Delhi, Dwarka, Delhi—110077 (India); Lee, Dong-Hun [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)] [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)

    2013-11-15

    Test-particle simulations of electrons interacting with finite-amplitude, obliquely propagating whistler waves are carried out in order to investigate the acceleration of relativistic electrons by these waves. According to the present findings, an efficient acceleration of relativistic electrons requires a narrow range of oblique propagation angles, close to the whistler resonance cone angle, when the wave amplitude is held constant at relatively low value. For a constant wave propagation angle, it is found that a range of oblique whistler wave amplitudes permits the acceleration of relativistic electrons to O(MeV) energies. An initial distribution of test electrons is shown to form a power-law distribution when plotted in energy space. It is also found that the acceleration is largely uniform in electron pitch-angle space.

  8. Stability of non-linear integrable accelerator

    SciTech Connect

    Batalov, I.; /Moscow, MIPT; Valishev, A.; /Fermilab

    2011-09-01

    The stability of non-linear Integrable Optics Test Accelerator (IOTA) model developed in [1] was tested. The area of the stable region in transverse coordinates and the maximum attainable tune spread were found as a function of non-linear lens strength. Particle loss as a function of turn number was analyzed to determine whether a dynamic aperture limitation present in the system. The system was also tested with sextupoles included in the machine for chromaticity compensation. A method of evaluation of the beam size in the linear part of the accelerator was proposed.

  9. Exercise Versus +Gz Acceleration Training

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Simonson, S. R.; Stocks, J. M.; Evans, J. M.; Knapp, C. F.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Decreased working capacity and "orthostatic" intolerance are two major problems for astronauts during and after landing from spaceflight in a return vehicle. The purpose was to test the hypotheses that (1) supine-passive-acceleration training, supine-interval-exercise plus acceleration training, and supine exercise plus acceleration training will improve orthostatic tolerance (OT) in ambulatory men; and that (2) addition of aerobic exercise conditioning will not influence this enhanced OT from that of passive-acceleration training. Seven untrained men (24-38 yr) underwent 3 training regimens (30 min/d x 5d/wk x 3wk on the human-powered centrifuge - HPC): (a) Passive acceleration (alternating +1.0 Gz to 50% Gzmax); (b) Exercise acceleration (alternating 40% - 90% V02max leg cycle exercise plus 50% of HPCmax acceleration); and (c) Combined intermittent exercise-acceleration at 40% to 90% HPCmax. Maximal supine exercise workloads increased (P < 0.05) by 8.3% with Passive, by 12.6% with Exercise, and by 15.4% with Combined; but maximal V02 and HR were unchanged in all groups. Maximal endurance (time to cessation) was unchanged with Passive, but increased (P < 0.05) with Exercise and Combined. Resting pre-tilt HR was elevated by 12.9% (P < 0.05) only after Passive training, suggesting that exercise training attenuated this HR response. All resting pre-tilt blood pressures (SBP, DBP, MAP) were not different pre- vs. post-training. Post-training tilt-tolerance time and HR were increased (P < 0.05) only with Passive training by 37.8% and by 29.1%, respectively. Thus, addition of exercise training attenuated the increased Passive tilt tolerance. Resting (pre-tilt) and post-tilt cardiac R-R interval, stroke volume, end-diastolic volume, and cardiac output were all uniformly reduced (P < 0.05) while peripheral resistance was uniformly increased (P < 0.05) pre-and post-training for the three regimens indicating no effect of any training regimen on those cardiovascular variables. Plasma volume (% delta) was uniformly decreased by 8% to 14% (P < 0.05) at tilt-tolerance pre- vs. post-training for all regimens indicating no effect of these training regimens on the level of vascular fluid shifts.

  10. Trends in electron accelerator applications

    NASA Astrophysics Data System (ADS)

    Kapitza, S. P.; Tsipenyuk, Yu. M.

    1998-04-01

    The development of electron accelerators has led over the last decades to technologies that permit to build machines of great energies and power. For energies up to 30-40 MeV research and practical applications are numerous and they are considered in some detail. Medical and radiological uses, nondestructive testing, injectors to larger accelerators, storage rings and free electron lasers are typical for medium sized acclerators. Of special interest is the use of electron accelerators for production of short-lived isotopes and activation analysis. Special attention is paid to a possibility of X-ray production through transition, parametric and channeling radiations, as well as a possibility of creation of a tunable monochromatic gamma-ray source up to 1 MeV energy. Thus a medium powered electron accelerator asa universal radiation source of electrons, bremsstrahlung, X-rays and neutrons is a modern and versatile facility, that can now be considered to take the place of research nuclear reactors.

  11. Heavy Ion Fusion Accelerator Research (HIFAR)

    SciTech Connect

    Not Available

    1991-04-01

    This report discusses the following topics: emittance variations in current-amplifying ion induction lina; transverse emittance studies of an induction accelerator of heavy ions; drift compression experiments on MBE-4 and related emittance; low emittance uniform- density C{sub s}+ sources for heavy ion fusion accelerator studies; survey of alignment of MBE-4; time-of-flight dependence on the MBE-4 quadrupole voltage; high order calculation of the multiple content of three dimensional electrostatic geometries; an induction linac injector for scaled experiments; induction accelerator test module for HIF; longitudinal instability in HIF beams; and analysis of resonant longitudinal instability in a heavy ion induction linac.

  12. Chronic Low Back Pain in Young Korean Urban Males: The Life-Time Prevalence and Its Impact on Health Related Quality of Life

    PubMed Central

    Shim, Jae-Hyun; Yoon, Sang-Young; Lee, Chang-Hoon; Doh, Jae-Won; Bae, Hack-Gun

    2014-01-01

    Objective We assessed the life-time prevalence (LTP) of chronic low back pain (LBP) in young Korean males. We also evaluated the relationship between lumbar spinal lesions and their health related quality-of-life (HRQOL). Methods A cross-sectional, self-reported survey was conducted in Korean males (aged 19-year-old) who underwent physical examinations for the conscript. We examined 3331 examinees in November 2014. We included 2411 subjects, who accepted to participate this study without any comorbidities. We interviewed using simple binary questions for their LBP experience and chronicity. HRQOL was assessed by Short-Form Health-Survey-36 (SF-36) in chronic LBP and healthy control groups. Radiological assessment was performed in chronic LBP group to determine whether there were any pathological causes of their symptoms. Results The LTP of chronic LBP was 13.4%. Most (71.7%) of them didn't have any lumbar spinal lesions (i.e., non-specific chronic LBP). The SF-36 subscale and summary scores were significantly lower in subjects with chronic LBP. Between specific and non-specific chronic LBP group, all physical and mental subscale scores were significantly lower in specific chronic LBP group, except mental health (MH) subscale score. In MH subscale and mental component summary score, statistical significant differences didn't appear between two groups (p=0.154, 0.126). Conclusion In Korean males 19 years of age, the LTP of chronic LBP was 13.4%, and more than two-thirds were non-specific chronic LBP. Chronic LBP had a significant impact on HRQOL. The presence of lumbar spinal pathoanatomical lesions affected mainly on the physical aspect of HRQOL. It influenced little on the mental health. PMID:25628807

  13. Research and development of a plasma jet mass accelerator as a driver for impact fusion

    Microsoft Academic Search

    S. A. Goldstein; D. A. Tidman; R. L. Burton; D. W. Massey; N. K. Winsor

    1984-01-01

    A ten module accelerator was designed, fabricated, and tested at projectile velocities up to 5 km\\/sec. It is shown that a projectile with mass less than a half gram is able to be accelerated by a succession of momentum kicks from plasma jets. The significance of this acceleration mechanism is that it is usable, in principle, to accelerate projectiles to

  14. Particle acceleration at oblique shocks and discon tinuities of the density profile

    E-print Network

    Gieseler, Udo D. J.

    Particle acceleration at oblique shocks and discon­ tinuities of the density profile U. D. J acceleration, the phase space spectral index s of accelerated particles depends solely on the compression ratio, the density profile of accelerated test particles is a continuous function of position (e.g., Kirk 1994, page

  15. Progress on the MIT Photonic Band Gap Accelerator Experiment

    SciTech Connect

    Smirnova, E.I. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Earley, L.M. [Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Mastovky, I.; Shapiro, M.A.; Temkin, R.J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2004-12-07

    We report the progress on the design and cold test of metallic photonic band gap (PBG) resonators and PBG accelerator structures. First, an 11 GHz PBG resonator, which can be utilized as an accelerator cavity with reduced long-range wakefields, was constructed and tested. The higher-order-modes suppression was proved in the cold test. A Q-factor of 5000 was achieved for a brazed resonator. Next, a 6-cell 17.137 GHz PBG accelerator structure with reduced long-range wakefields was designed. A high Q 6-cell 17.137 GHz PBG accelerator was electroformed and is currently cold tested. A PBG structure will be tested at high power and will be used to accelerate an electron beam at Massachusetts Institute of Technology.

  16. The data this time will be the Motorcycle Acceleration Data: A data frame giving a series of measurements of head acceleration

    E-print Network

    Zeng, Donglin

    Cosines The data this time will be the Motorcycle Acceleration Data: A data frame giving a series of measurements of head acceleration in a simulated motorcycle accident, used to test crash helmets. Usage: data

  17. Characteristics of an electron-beam rocket pellet accelerator

    SciTech Connect

    Tsai, C.C.; Foster, C.A.; Schechter, D.E.

    1989-01-01

    An electron-beam rocket pellet accelerator has been designed, built, assembled, and tested as a proof-of-principle (POP) apparatus. The main goal of accelerators based on this concept is to use intense electron-beam heating and ablation of a hydrogen propellant stick to accelerate deuterium and/or tritium pellets to ultrahigh speeds (10 to 20 km/s) for plasma fueling of next-generation fusion devices such as the International Thermonuclear Engineering Reactor (ITER). The POP apparatus is described and initial results of pellet acceleration experiments are presented. Conceptual ultrahigh-speed pellet accelerators are discussed. 14 refs., 8 figs.

  18. Studies of dished accelerator grids for 30-cm ion thrusters

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1973-01-01

    Geometrically different sets of dished accelerator grids were tested on five 30-cm thrusters. The geometric variation of the grids included the grid-to-grid spacing, the screen and accelerator hole diameters and thicknesses, the screen and accelerator open area fractions, ratio of dish depth to the dish diameter, compensation, and aperture shape. In general, the data taken over a range of beam currents for each grid set included the minimum total accelerating voltage required to extract a given beam current and the minimum accelerator grid voltage required to prevent electron backstreaming.

  19. Leaky Fermi accelerators

    NASA Astrophysics Data System (ADS)

    Shah, Kushal; Gelfreich, Vassili; Rom-Kedar, Vered; Turaev, Dmitry

    2015-06-01

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for a sufficiently long time. The heat production is found to depend strongly on the type of Fermi accelerator. An ergodic accelerator, i.e., one that has a single ergodic component, produces a weaker energy flow than a multicomponent accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multicomponent case the energy flow may be significantly increased by shrinking the hole size.

  20. Spin, Acceleration and Gravity

    E-print Network

    Donato Bini; Christian Cherubini; Bahram Mashhoon

    2004-06-14

    The massless field perturbations of the accelerating Minkowski and Schwarzschild spacetimes are studied. The results are extended to the propagation of the Proca field in Rindler spacetime. We examine critically the possibility of existence of a general spin-acceleration coupling in complete analogy with the well-known spin-rotation coupling. We argue that such a direct coupling between spin and linear acceleration does not exist.