Science.gov

Sample records for seu hospedeiro intermediario

  1. SEU In An Advanced Bipolar Integrated Circuit

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Secrest, Elaine C.; Berndt, Dale F.

    1989-01-01

    Report summarizes investigation of single-event upsets (SEU) in bipolar integrated-circuit set of flip-flops (memory cells). Device tested made by advanced digital bipolar silicon process of Honeywell, Inc. Circuit chip contained 4 cells. Construction enabled study of effect of size on SEU behavior. Each cell externally biased so effect of bias current on SEU behavior. Results of study provides important information for optimal design of devices fabricated using buried-layer bipolar process operating in heavy-ion SEU environments. Designers use information to provide required levels of suppression of SEU in specific applications via combinations of size and/or cell-current scaling.

  2. Critical issues regarding SEU in avionics

    SciTech Connect

    Normand, E. ); McNulty, P.J. )

    1993-01-01

    The energetic neutrons in the atmosphere cause microelectronics in avionic system to malfunction through a mechanism called single-event upsets (SEUs), and single-event latchup is a potential threat. Data from military and experimental flights as well as laboratory testing indicate that typical non-radiation-hardened 64K and 256K static random access memories (SRAMs) can experience a significant SEU rate at aircraft altitudes. Microelectronics in avionics systems have been demonstrated to be susceptible to SEU. Of all device types, RAMs are the most sensitive because they have the largest number of bits on a chip (e.g., an SRAM may have from 64K to 1M bits, a microprocessor 3K to 10K bits, and a logic device like an analog-to-digital converter, 12 bits). Avionics designers will need to take this susceptibility into account in current and future designs. A number of techniques are available for dealing with SEU: EDAC, redundancy, use of SEU-hard parts, reset and/or watchdog timer capability, etc. Specifications should be developed to guide avionics vendors in the analysis, prevention, and verification of neutron-induced SEU. Areas for additional research include better definition of the atmospheric neutrons and protons, development of better calculational models (e.g., those used for protons[sup 11]), and better characterization of neutron-induced latchup.

  3. Low power SEU immune CMOS memory circuits

    NASA Technical Reports Server (NTRS)

    Liu, M. N.; Whitaker, Sterling

    1992-01-01

    The authors report a design improvement for CMOS static memory circuits hardened against single event upset (SEU) using a recently proposed logic/circuit design technique. This improvement drastically reduces static power consumption, reduces the number of transistors required in a D flip-flop design, and eliminates the possibility of capturing an upset state in the slave section during a clock transition.

  4. SEU hardening of CMOS memory circuit

    NASA Technical Reports Server (NTRS)

    Whitaker, S.; Canaris, J.; Liu, K.

    1990-01-01

    This paper reports a design technique to harden CMOS memory circuits against Single Event Upset (SEU) in the space environment. A RAM cell and Flip Flop design are presented to demonstrate the method. The Flip Flop was used in the control circuitry for a Reed Solomon encoder designed for the Space Station.

  5. Refined Transistor Model For Simulation Of SEU

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Benumof, Reuben

    1988-01-01

    Equivalent base resistance added. Theoretical study develops equations for parameters of Gummel-Poon model of bipolar junction transistor: includes saturation current, amplification factors, charging times, knee currents, capacitances, and resistances. Portion of study concerned with base region goes beyond Gummel-Poon analysis to provide more complete understanding of transistor behavior. Extended theory useful in simulation of single-event upset (SEU) caused in logic circuits by cosmic rays or other ionizing radiation.

  6. Simulation of SEU transients in CMOS ICs

    SciTech Connect

    Kaul, N.; Bhuva, B.L.; Kerns, S.E. )

    1991-12-01

    This paper reports that available analytical models of the number of single-event-induced errors (SEU) in combinational logic systems are not easily applicable to real integrated circuits (ICs). An efficient computer simulation algorithm set, SITA, predicts the vulnerability of data stored in and processed by complex combinational logic circuits to SEU. SITA is described in detail to allow researchers to incorporate it into their error analysis packages. Required simulation algorithms are based on approximate closed-form equations modeling individual device behavior in CMOS logic units. Device-level simulation is used to estimate the probability that ion-device interactions produce erroneous signals capable of propagating to a latch (or n output node), and logic-level simulation to predict the spread of such erroneous, latched information through the IC. Simulation results are compared to those from SPICE for several circuit and logic configurations. SITA results are comparable to this established circuit-level code, and SITA can analyze circuits with state-of-the-art device densities (which SPICE cannot). At all IC complexity levels, SITAS offers several factors of 10 savings in simulation time over SPICE.

  7. SEU System Analysis: Not Just the Sum of All Parts

    NASA Technical Reports Server (NTRS)

    Berg, Melanie D.; Label, Kenneth

    2014-01-01

    Single event upset (SEU) analysis of complex systems is challenging. Currently, system SEU analysis is performed by component level partitioning and then either: the most dominant SEU cross-sections (SEUs) are used in system error rate calculations; or the partition SEUs are summed to eventually obtain a system error rate. In many cases, system error rates are overestimated because these methods generally overlook system level derating factors. The problem with overestimating is that it can cause overdesign and consequently negatively affect the following: cost, schedule, functionality, and validation/verification. The scope of this presentation is to discuss the risks involved with our current scheme of SEU analysis for complex systems; and to provide alternative methods for improvement.

  8. A SEU-Hard Flip-Flop for Antifuse FPGAs

    NASA Technical Reports Server (NTRS)

    Katz, R.; Wang, J. J.; McCollum, J.; Cronquist, B.; Chan, R.; Yu, D.; Kleyner, I.; Day, John H. (Technical Monitor)

    2001-01-01

    A single event upset (SEU)-hardened flip-flop has been designed and developed for antifuse Field Programmable Gate Array (FPGA) application. Design and application issues, testability, test methods, simulation, and results are discussed.

  9. Characterization of System Level Single Event Upset (SEU) Responses using SEU Data, Classical Reliability Models, and Space Environment Data

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Label, Kenneth; Campola, Michael; Xapsos, Michael

    2017-01-01

    We propose a method for the application of single event upset (SEU) data towards the analysis of complex systems using transformed reliability models (from the time domain to the particle fluence domain) and space environment data.

  10. A new method for using Cf-252 in SEU testing

    NASA Technical Reports Server (NTRS)

    Costantine, A.; Howard, J. W.; Becker, M.; Block, R. C.; Smith, L. S.; Soli, G. A.; Stauber, M. C.

    1990-01-01

    A system using Cf-252 and associated nuclear instrumentation has determined the single-event upset (SEU) cross section versus linear energy transfer (LET) curve for several 2K x 8 static random access memories (SRAMs). The Cf-252 fission fragments pass through a thin-film organic scintillator detector (TFD) on the way to the device under test (DUT). The TFD provides energy information for each transiting fragment. Data analysis provides the energy of the individual ion responsible for each SEU; thus, separate upset cross sections can be developed for different energy and mass regions of the californium spectrum. This californium-based device is quite small and fits onto a bench top. It provides a convenient and inexpensive supplement or alternative to accelerator and high-altitude/space SEU testing.

  11. SEU43 fuel bundle shielding analysis during spent fuel transport

    SciTech Connect

    Margeanu, C. A.; Ilie, P.; Olteanu, G.

    2006-07-01

    The basic task accomplished by the shielding calculations in a nuclear safety analysis consist in radiation doses calculation, in order to prevent any risks both for personnel protection and impact on the environment during the spent fuel manipulation, transport and storage. The paper investigates the effects induced by fuel bundle geometry modifications on the CANDU SEU spent fuel shielding analysis during transport. For this study, different CANDU-SEU43 fuel bundle projects, developed in INR Pitesti, have been considered. The spent fuel characteristics will be obtained by means of ORIGEN-S code. In order to estimate the corresponding radiation doses for different measuring points the Monte Carlo MORSE-SGC code will be used. Both codes are included in ORNL's SCALE 5 programs package. A comparison between the considered SEU43 fuel bundle projects will be also provided, with CANDU standard fuel bundle taken as reference. (authors)

  12. A new method for using Cf-252 in SEU testing

    NASA Technical Reports Server (NTRS)

    Costantine, A.; Howard, J. W.; Becker, M.; Block, R. C.; Smith, L. S.; Soli, G. A.; Stauber, M. C.

    1990-01-01

    A system using Cf-252 and associated nuclear instrumentation has determined the single-event upset (SEU) cross section versus linear energy transfer (LET) curve for several 2K x 8 static random access memories (SRAMs). The Cf-252 fission fragments pass through a thin-film organic scintillator detector (TFD) on the way to the device under test (DUT). The TFD provides energy information for each transiting fragment. Data analysis provides the energy of the individual ion responsible for each SEU; thus, separate upset cross sections can be developed for different energy and mass regions of the californium spectrum. This californium-based device is quite small and fits onto a bench top. It provides a convenient and inexpensive supplement or alternative to accelerator and high-altitude/space SEU testing.

  13. An SEU-Tolerant DICE Latch Design With Feedback Transistors

    NASA Astrophysics Data System (ADS)

    Wang, H.-B.; Li, Y.-Q.; Chen, L.; Li, L.-X.; Liu, R.; Baeg, S.; Mahatme, N.; Bhuva, B. L.; Wen, S.-J.; Wong, R.; Fung, R.

    2015-04-01

    This paper presents an SEU-tolerant Dual Interlocked Storage Cell (DICE) latch design with both PMOS and NMOS transistors in the feedback paths. The feedback transistors improve the SEU tolerance by increasing the feedback loop delay during the hold mode. The latch design was implemented in a shift register fashion at a 130-nm bulk CMOS process node. Exposures to heavy-ions exhibited a significantly higher upset LET threshold and lower cross-section compared with the traditional DICE latch design. Performance penalties in terms of write delay, power, and area are non-significant compared to traditional DICE design.

  14. Test results for SEU and SEL immune memory circuits

    NASA Technical Reports Server (NTRS)

    Wiseman, D.; Canaris, J.; Whitaker, S.; Gambles, J.; Arave, K.; Arave, L.

    1993-01-01

    Test results for three SEU logic/circuit hardened CMOS memory circuits verify upset and latch-up immunity for two configurations to be in excess of 120 MeV cm(exp 2)/mg using a commercial, non-radiation hardened CMOS process. Test chips from three separate fabrication runs in two different process were evaluated.

  15. SEU characterization and design dependence of the SA3300 microprocessor

    SciTech Connect

    Sexton, F.W.; Treece, R.K.; Axness, C.L.; Hughes, K.H.; Hash, G.L.; Hass, K.J.

    1990-01-01

    The SA3300 16-bit microprocessor is a key component for interplanetary space probes to be launched in the 1990's. A full SEU characterization of the D-latches of the SA3300 is given, including pattern sensitivity and temperature. 9 refs., 5 figs.

  16. A summary of SEU test results using californium-252

    SciTech Connect

    Sorensen, R.H.; Adams, L.; Sanderson, T.K.

    1988-12-01

    This paper presents a summary of four years Single Event Upset (SEU) test results on a wide range of devices and technologies using Californium-252 having an average Linear Energy Transfer (LET) = 43 MeV/(mg/sqcm). Sensitivity variations are highlighted, particularly for nominally identical devices. The significance of the testing and test data with respect to recent devices and technologies is discussed.

  17. SEU mitigation strategies for SRAM-based FPGA

    NASA Astrophysics Data System (ADS)

    Luo, Pei; Zhang, Jian

    2011-08-01

    The type of Field Programmable Gate Arrays (FPGAs) technology and device family used in a design is a key factor for system reliability. Though antifuse-based FPGAs are widely used in aerospace because of their high reliability, current antifuse-based FPGA devices are expensive and leave no room for mistakes or changes since they are not reprogrammable. The substitute for antifuse-based FPGAs are needed in aerospace design, they should be both reprogrammable and highly reliable to Single Event Upset effects (SEUs). SRAM-based FPGAs are widely and systematically used in complex embedding digital systems both in a single chip industry and commercial applications. They are reprogrammable and high in density because of the smaller SRAM cells and logic structures. But the SRAM-based FPGAs are especially sensitive to cosmic radiation because the configuration information is stored in SRAM memory. The ideal FPGA for aerospace use should be high-density SRAM-based which is also insensitive to cosmic radiation induced SEUs. Therefore, in order to enable the use of SRAM-based FPGAs in safety critical applications, new techniques and strategies are essential to mitigate the SEU errors in such devices. In order to improve the reliability of SRAM-based FPGAs which are very sensitive to SEU errors, techniques such as reconfiguration and Triple Module Redundancy (TMR) are widely used in the aerospace electronic systems to mitigate the SEU and Single Event Functional Interrupt (SEFI) errors. Compared to reconfiguration and triplication, scrubbing and partial reconfiguration will utilize fewer or even no internal resources of FPGA. What's more, the detection and repair process can detect and correct SEU errors in configuration memories of the FPGA without affecting or interrupting the proper working of the system while reconfiguration would terminate the operation of the FPGA. This paper presents a payload system realized on Xilinx Virtex-4 FPGA which mitigates SEU effects in the

  18. Methods for calculating SEU rates for bipolar and NMOS circuits

    NASA Astrophysics Data System (ADS)

    McNulty, P. J.; Abdel-Kader, W. G.; Bisgrove, J. M.

    1985-12-01

    Computer codes developed at Clarkson for simulating charge generation by proton-induced nuclear reactions in well-defined silicon microstructures can be used to calculate SEU rates for specific devices when the critical charge and the dimensions of all SEU sensitive junctions on the device are known, provided one can estimate the contribution from externally-generated charge which enters the sensitive junction by drift and diffusion. Calculations for two important bipolar devices, the AMD 2901B bit slice and the Fairchild 93L422 RAM, for which the dimensions of the sensitive volumes were estimated from available heavy-ion test data, have been found to be in agreement with experimental data. Circuit data for the Intel 2164A, an alpha sensitive dRAM, was provided by the manufacturer. Calculations based on crude assumptions regarding which nuclear recoils and which alphas trigger upsets in the 2164A were found to agree with experimental data.

  19. Analyzing Test-As-You-Fly Single Event Upset (SEU) Responses using SEU Data, Classical Reliability Models, and Space Environment Data

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Label, Kenneth; Campola, Michael; Xapsos, Michael

    2017-01-01

    We propose a method for the application of single event upset (SEU) data towards the analysis of complex systems using transformed reliability models (from the time domain to the particle fluence domain) and space environment data.

  20. Characterization of System on a Chip (SoC) Single Event Upset (SEU) Responses Using SEU Data, Classical Reliability Models, and Space Environment Data

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Label, Kenneth; Campola, Michael; Xapsos, Michael

    2017-01-01

    We propose a method for the application of single event upset (SEU) data towards the analysis of complex systems using transformed reliability models (from the time domain to the particle fluence domain) and space environment data.

  1. SEU-tolerant IQ detection algorithm for LLRF accelerator system

    NASA Astrophysics Data System (ADS)

    Grecki, M.

    2007-08-01

    High-energy accelerators use RF field to accelerate charged particles. Measurements of effective field parameters (amplitude and phase) are tasks of great importance in these facilities. The RF signal is downconverted in frequency but keeping the information about amplitude and phase and then sampled in ADC. One of the several tasks for LLRF control system is to estimate the amplitude and phase (or I and Q components) of the RF signal. These parameters are further used in the control algorithm. The XFEL accelerator will be built using a single-tunnel concept. Therefore electronic devices (including LLRF control system) will be exposed to ionizing radiation, particularly to a neutron flux generating SEUs in digital circuits. The algorithms implemented in FPGA/DSP should therefore be SEU-tolerant. This paper presents the application of the WCC method to obtain immunity of IQ detection algorithm to SEUs. The VHDL implementation of this algorithm in Xilinx Virtex II Pro FPGA is presented, together with results of simulation proving the algorithm suitability for systems operating in the presence of SEUs.

  2. SEU response of design- and resistor-hardened D-latches in the SA3300 microprocessor

    SciTech Connect

    Sexton, F.W.; Corbett, W.T.; Axness, C.L.; Wunsch, T.F.; Hughes, K.L.; Treece, R.K.; Hass, K.J.; Hash, G.L.; Shaneyfelt, M.R.

    1991-01-01

    The effectiveness of hardening the SA3300 against SEU using design and design-plus-resistor approaches is presented. The full performance and SEU tolerance requirements are met using R{sub fb} {le} 160 k{Omega}. Lumped-parameter circuit simulations are used to analyze results. 10 refs., 5 figs.

  3. Recent Results on SEU Hardening of SiGe HBT Logic Circuits

    NASA Technical Reports Server (NTRS)

    Krithivasan, Ramkumar; Marshall, Paul W.; Nayeem, Mustayeen; Sutton, Akil K.; Kuo, Wei-Min Lance; Haugerud, Becca M.; Najafizadeh, Laieh; Cressler, John D.; Carts, martin A.; Marshall, Cheryl J.

    2006-01-01

    A viewgraph presentation on SEU tolerant SiGe HBT technology is shown. The topics include: 1) Introduction; 2) TID and SEU in SiGe Technology; 3) RHBD Techniques; 4) Experiment; 5) Heavy-Ion Data and Analysis; and 6) Summary.

  4. Measurements of SEU and total dose in geostationary orbit under normal and solar flare conditions

    SciTech Connect

    Adams, L.; Daly, E.J.; Harboe-Sorensen, R. ); Holmes-Siedle, A.G. ); Ward, A.K.; Bull, R.A. )

    1991-12-01

    The Meteosat-3 Radiation Effects Experiment includes two 256 Kbit SRAMs configured for SEU detection and a RADFET array for dose measurement. SEU rates and doses are enhanced during solar flares. In this paper two years of orbital data are compared with ground tests and prediction.

  5. Energy-resolved neutron SEU measurements from 22 to 160 MeV

    SciTech Connect

    Johansson, K.; Dyreklev, P.; Granbom, B.; Olsson, N.; Blomgren, J.; Renberg, P.U.

    1998-12-01

    The energy dependence of the neutron- induced single-event upset (NSEU) cross section for Static RAMs have been measured, using quasi-monoenergetic neutrons of five different energies from 22 to 160 MeV. The measured SEU cross sections were corrected for the low-energy neutron tail by an iterative folding procedure. A clear energy dependence has been found. The SEU rate has been compared both with results from testing with a neutron spallation spectrum up to 800 MeV and the measured SEU rate from In-Flight experiments at 10 km.

  6. An analysis of the SEU rate of microcircuits exposed by the various components of space radiation.

    PubMed

    Bashkirov, V F; Kuznetsov, N V; Nymmik, R A

    1999-06-01

    In the present paper the experimental and calculated data of SEU rate in microcircuits operating onboard spacecraft are compared. The main features of models and the calculation methods, which are incorporated in the SEREIS software package, are considered. The main features of models, and the calculation methods are considered. The contribution of the different space radiation components (ERB Protons; GCR particles and SEPs) to the SEU rate is discussed with an allowance for the shielding thickness.

  7. Upper bound SEU rate for devices in an isotropic or nonisotropic flux

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1991-01-01

    A method for constructing upper bound estimates for device single event upset (SEU) rates is presented. A directional Heinrich flux, as a function of direction, must be known. A computer code, included, converts the directional Heinrich flux into an 'effective flux'. The effective flux provides a simple way to estimate upper bound SEU rates for devices with a known normal incident cross section versus LET curve.

  8. Observation and prediction of SEU in Hitachi SRAMs in low altitude polar orbits

    SciTech Connect

    Harboe-Sorensen, R.; Daly, E.J.; Adams, L. ); Underwood, C.I. . Surrey Satellite Technology); Mueller, R. . Institut fuer Datenverarbeitungsanlagen)

    1993-12-01

    In-orbit SEU data from three microsatellites are separated into Galactic Cosmic Ray (GCR), South Atlantic Anomaly (SAA) and solar flare upsets. Heavy ion and proton testing of the same devices are reported and predictions using LET-dependent ion cross sections and a 2-parameter fit to proton cross section data are compared with in-flight data. SEU trends in memory devices from a single manufacturer, from 16 K-bit to 4 M-bit, are identified.

  9. Single Event Upset (SEU) testing of semiconductor components at the McMaster Accelerator Laboratory

    NASA Astrophysics Data System (ADS)

    Davies, J. A.; Almeida, F. J. D.; Comedi, D.; Stark, J. W.

    1991-03-01

    Single event upsets (SEU) occur when a single ionizing particle such as a cosmic ray passes through a microelectronic device, causing a random change in the logic state of a bistable circuit. The SEU phenomenon is of great interest since it is a source of errors and failures, notably on spaceborne microelectronic chips. A Van de Graaff accelerator was used to simulate the cosmic ray heavy ion linear energy transfer (LET) distribution found in earth orbit, and accelerator experiments were conducted in a dedicated facility for SEU testing of microelectronic devices. The first set of experiments set out to compare data obtained by two different SEU memory tester systems, and a second set attempted to compare data obtained using ions of different species and energy but the same LET, and to determine the accuracy of the concept of a constant SEU cross-section for a given LET. Observation of a fluence dependent SEU cross section and transient behavior led to a third set of experiments, designed to allow observation in more detail of the dynamics of these newly observed phenomena. The charge collection efficiency of detectors to high LET ions was also measured.

  10. Research on SEU hardening of heterogeneous Dual-Core SoC

    NASA Astrophysics Data System (ADS)

    Huang, Kun; Hu, Keliu; Deng, Jun; Zhang, Tao

    2017-08-01

    The implementation of Single-Event Upsets (SEU) hardening has various schemes. However, some of them require a lot of human, material and financial resources. This paper proposes an easy scheme on SEU hardening for Heterogeneous Dual-core SoC (HD SoC) which contains three techniques. First, the automatic Triple Modular Redundancy (TMR) technique is adopted to harden the register heaps of the processor and the instruction-fetching module. Second, Hamming codes are used to harden the random access memory (RAM). Last, a software signature technique is applied to check the programs which are running on CPU. The scheme need not to consume additional resources, and has little influence on the performance of CPU. These technologies are very mature, easy to implement and needs low cost. According to the simulation result, the scheme can satisfy the basic demand of SEU-hardening.

  11. Design and qualification of the SEU/TD Radiation Monitor chip

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G.; Blaes, Brent R.; Soli, George A.; Zamani, Nasser; Hicks, Kenneth A.

    1992-01-01

    This report describes the design, fabrication, and testing of the Single-Event Upset/Total Dose (SEU/TD) Radiation Monitor chip. The Radiation Monitor is scheduled to fly on the Mid-Course Space Experiment Satellite (MSX). The Radiation Monitor chip consists of a custom-designed 4-bit SRAM for heavy ion detection and three MOSFET's for monitoring total dose. In addition the Radiation Monitor chip was tested along with three diagnostic chips: the processor monitor and the reliability and fault chips. These chips revealed the quality of the CMOS fabrication process. The SEU/TD Radiation Monitor chip had an initial functional yield of 94.6 percent. Forty-three (43) SEU SRAM's and 14 Total Dose MOSFET's passed the hermeticity and final electrical tests and were delivered to LL.

  12. The Single Event Upset (SEU) response to 590 MeV protons

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Smith, L. S.; Soli, G. A.

    1984-01-01

    The presence of high-energy protons in cosmic rays, solar flares, and trapped radiation belts around Jupiter poses a threat to the Galileo project. Results of a test of 10 device types (including 1K RAM, 4-bit microP sequencer, 4-bit slice, 9-bit data register, 4-bit shift register, octal flip-flop, and 4-bit counter) exposed to 590 MeV protons at the Swiss Institute of Nuclear Research are presented to clarify the picture of SEU response to the high-energy proton environment of Jupiter. It is concluded that the data obtained should remove the concern that nuclear reaction products generated by protons external to the device can cause significant alteration in the device SEU response. The data also show only modest increases in SEU cross section as proton energies are increased up to the upper limits of energy for both the terrestrial and Jovian trapped proton belts.

  13. SPICE analysis of the SEU sensitivity of a fully depleted SOI CMOS SRAM cell

    SciTech Connect

    Alles, M.L. )

    1994-12-01

    Fully depleted silicon-on-insulator (SOI) technologies are of interest for commercial applications as well as for use in harsh (radiation-intensive) environments. In both types of application, effects of charged particles (single-event effects) are of concern. Here, SPICE analysis of SEU sensitivity of a 6-T SRAM cell using commercially-representative fully depleted SOI CMOS technology parameters indicates that reduction of the minority carrier lifetime (parasitic bipolar gain) and use of thinner silicon can significantly reduce SEU sensitivity.

  14. Simulation of SEU Cross-sections using MRED under Conditions of Limited Device Information

    NASA Technical Reports Server (NTRS)

    Lauenstein, J. M.; Reed, R. A.; Weller, R. A.; Mendenhall, M. H.; Warren, K. M.; Pellish, J. A.; Schrimpf, R. D.; Sierawski, B. D.; Massengill, L. W.; Dodd, P. E.; Shaneyfelt, M. R.; Felix, J. A.; Schwank, J. R.

    2007-01-01

    This viewgraph presentation reviews the simulation of Single Event Upset (SEU) cross sections using the membrane electrode assembly (MEA) resistance and electrode diffusion (MRED) tool using "Best guess" assumptions about the process and geometry, and direct ionization, low-energy beam test results. This work will also simulate SEU cross-sections including angular and high energy responses and compare the simulated results with beam test data for the validation of the model. Using MRED, we produced a reasonably accurate upset response model of a low-critical charge SRAM without detailed information about the circuit, device geometry, or fabrication process

  15. Variation in proton-induced upsets rates from large solar flares using an improved SEU model

    NASA Astrophysics Data System (ADS)

    Normand, Eugene; Stapor, William J.

    1990-12-01

    Proton integral flux measurements during solar energetic particle (SEP) events, from the CPME instrument onboard the IMP-8 satellite, and the proton detector on the GOES-7 satellite, are utilized to calculate proton-induced single-event upset (SEU). An improved two-parameter SEU cross section model is used for three RAM devices. The log of the 239 actual RAM upsets on the TDRS-1 satellite during the October 19, 1989 SEP event allowed a comparison between the recorded number of upsets/chip per day and those predicted based on the GOES-7 data, the two-parameter model, and the shielding distribution curve.

  16. Empirical modeling of Single-Event Upset (SEU) in NMOS depletion-mode-load static RAM (SRAM) chips

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Smith, S. L.; Atwood, G. E.

    1986-01-01

    A detailed experimental investigation of single-event upset (SEU) in static RAM (SRAM) chips fabricated using a family of high-performance NMOS (HMOS) depletion-mode-load process technologies, has been done. Empirical SEU models have been developed with the aid of heavy-ion data obtained with a three-stage tandem van de Graaff accelerator. The results of this work demonstrate a method by which SEU may be empirically modeled in NMOS integrated circuits.

  17. Empirical modeling of Single-Event Upset (SEU) in NMOS depletion-mode-load static RAM (SRAM) chips

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Smith, S. L.; Atwood, G. E.

    1986-01-01

    A detailed experimental investigation of single-event upset (SEU) in static RAM (SRAM) chips fabricated using a family of high-performance NMOS (HMOS) depletion-mode-load process technologies, has been done. Empirical SEU models have been developed with the aid of heavy-ion data obtained with a three-stage tandem van de Graaff accelerator. The results of this work demonstrate a method by which SEU may be empirically modeled in NMOS integrated circuits.

  18. Single-Event Upset (SEU) model verification and threshold determination using heavy ions in a bipolar static RAM

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Thieberger, P.; Wegner, H. E.

    1985-01-01

    Single-Event Upset (SEU) response of a bipolar low-power Schottky-diode-clamped TTL static RAM has been observed using Br ions in the 100-240 MeV energy range and O ions in the 20-100 MeV range. These data complete the experimental verification of circuit-simulation SEU modeling for this device. The threshold for onset of SEU has been observed by the variation of energy, ion species and angle of incidence. The results obtained from the computer circuit-simulation modeling and experimental model verification demonstrate a viable methodology for modeling SEU in bipolar integrated circuits.

  19. Single-Event Upset (SEU) model verification and threshold determination using heavy ions in a bipolar static RAM

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Thieberger, P.; Wegner, H. E.

    1985-01-01

    Single-Event Upset (SEU) response of a bipolar low-power Schottky-diode-clamped TTL static RAM has been observed using Br ions in the 100-240 MeV energy range and O ions in the 20-100 MeV range. These data complete the experimental verification of circuit-simulation SEU modeling for this device. The threshold for onset of SEU has been observed by the variation of energy, ion species and angle of incidence. The results obtained from the computer circuit-simulation modeling and experimental model verification demonstrate a viable methodology for modeling SEU in bipolar integrated circuits.

  20. Preliminary SEU analysis of the SAMPEX MIL-STD-1773 space-flight data

    NASA Astrophysics Data System (ADS)

    Crabtree, Christina M.; LaBel, Kenneth A.; Stassinopoulos, E. G.; Miller, Jay T.

    1993-09-01

    The Small Explorer Data System (SEDS) relies heavily on new technologies in the electrical designs. Among the key technologies utilized are fiber optics. The effects of the harsh space radiation environment on these spacecraft components can be quite severe. This paper takes a preliminary look at the single event upset (SEU) data seen during the early portion of SAMPEX flight (launched in July 1992) versus the ground test predictions. The new technologies are addressed along with the error handling abilities of the fiber optic system (MIL-STD-1773). The predicted SAMPEX radiation environment is discussed as well as the methodology of SEU rate prediction utilizing both cosmic ray and proton concerns. A comparison of the flight data to ground test predictions is discussed along with information concerning the significance of where and when the SEUs have occurred.

  1. A method to compute SEU fault probabilities in memory arrays with error correction

    NASA Technical Reports Server (NTRS)

    Gercek, Gokhan

    1994-01-01

    With the increasing packing densities in VLSI technology, Single Event Upsets (SEU) due to cosmic radiations are becoming more of a critical issue in the design of space avionics systems. In this paper, a method is introduced to compute the fault (mishap) probability for a computer memory of size M words. It is assumed that a Hamming code is used for each word to provide single error correction. It is also assumed that every time a memory location is read, single errors are corrected. Memory is read randomly whose distribution is assumed to be known. In such a scenario, a mishap is defined as two SEU's corrupting the same memory location prior to a read. The paper introduces a method to compute the overall mishap probability for the entire memory for a mission duration of T hours.

  2. Single-event upset (SEU) in a DRAM with on-chip error correction

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Schwartz, H. R.; Watson, R. K.; Hasnain, Z.; Nevile, L. R.

    1987-01-01

    Results are given of SEU measurements on 256K dynamic RAMs with on-chip error correction. They are claimed to be the first ever reported. A (12/8) Hamming error-correcting code was incorporated in the layout. Physical separation of the bits in each code word was used to guard against multiple bits being disrupted in any given word. Significant reduction in observed errors is reported.

  3. Altitude and latitude variations in avionics SEU and atmospheric neutron flux

    SciTech Connect

    Normand, E.; Baker, T.J. )

    1993-12-01

    The direct cause of single event upsets in SRAMs at aircraft altitudes by the atmospheric neutrons has previously been documented. The variation of the in-flight SEU rate with latitude is demonstrated by new data over a wide range of geographical locations. New measurements and models of the atmospheric neutron flux are also evaluated to characterize its variation with altitude, latitude and solar activity.

  4. Assessing the SEU resistance of CMOS latches using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, M.; Blaes, B.; Nixon, R.

    1990-01-01

    The importance of Cosmic Rays on the performance of integrated circuits (IC's) in a space environment is evident in the upset rate of the Tracking and Data Relay Satellite (TDRS) launched in Apr. 1983. This satellite experiences a single-event-upset (SEU) per day which must be corrected from the ground. Such experience caused a redesign of the Galileo spacecraft with SEU resistant IC's. The solution to the SEU problem continues to be important as the complexity of spacecraft grows, the feature size of IC's decreases, and as space systems are designed with circuits fabricated at non-radiation hardened foundries. This paper describes an approach for verifying the susceptibility of CMOS latches to heavy-ion induced state changes. The approach utilizes alpha particles to induce the upsets in test circuits. These test circuits are standard cells that have offset voltages which sensitize the circuits to upsets. These results are then used to calculate the upsetability at operating voltages. In this study results are presented for the alpha particle upset of a six-transistor static random access memory (SRAM) cell. Then a methodology is described for the analysis of a standard-cell inverter latch.

  5. Fiber optic temperature sensor using a Y2O2S:Eu thermographic phosphor

    NASA Astrophysics Data System (ADS)

    Smith, Todd V.; Smith, Barton

    1994-03-01

    This report details the development and testing of a thermographic-phosphor-based fiber-optic temperature sensor. The sensor is constructed by removing a region of the fiber jacket and cladding, then coating the exposed core with yttrium oxysulfide doped with a europium activator (Y2O2S:Eu). When photoexcited, the europium in the host lattice emits a sharp-line fluorescence spectrum that is characteristic of the temperature of the host crystal lattice. By measuring fluorescence lifetimes, we can deduce the temperature of an optical fiber that is in thermal contact with the fiber. Two different distributions of Y2O2S:Eu in the cladding region were evaluated with regard to light coupling efficiency. Theoretical waveguide calculations indicate that a thin core/cladding boundary distribution of Y2O2S:Eu couples light more efficiently into the cores guided modes than does a bulk distribution of phosphor in the cladding. The sensor tests showed reproducible response from 20 to 180 degrees Celsius. This technique has several advantages over other fiber optic temperature sensing techniques.

  6. Experimental evidence for a new single-event upset (SEU) mode in a CMOS SRAM obtained from model verification

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.; Lo, R. Y.

    1987-01-01

    Modeling of SEU has been done in a CMOS static RAM containing 1-micron-channel-length transistors fabricated from a p-well epilayer process using both circuit-simulation and numerical-simulation techniques. The modeling results have been experimentally verified with the aid of heavy-ion beams obtained from a three-stage tandem van de Graaff accelerator. Experimental evidence for a novel SEU mode in an ON n-channel device is presented.

  7. The contribution of low-energy protons to the total on-orbit SEU rate

    SciTech Connect

    Dodds, Nathaniel Anson; Martinez, Marino J.; Dodd, Paul E.; Shaneyfelt, Marty R.; Sexton, Frederick W.; Black, Jeffrey D.; Lee, David S.; Swanson, Scot E.; Bhuva, B. L.; Warren, K. M.; Reed, R. A.; Trippe, J.; Sierawski, B. D.; Weller, R. A.; Mahatme, N.; Gaspard, N.; Assis, T.; Austin, R.; Massengill, L. M.; Swift, G.; Wirthlin, M.; Cannon, M.; Liu, R.; Chen, L.; Kelly, A. T.; Marshall, P.; Trinczek, M.; Blackmore, E. W.; Wen, S. -J.; Wong, R.; Narasimham, B.; Pellish, J. A.; Puchner, H.; Weeden-Wright, S. L.

    2015-11-10

    Low- and high-energy proton experimental data and error rate predictions are presented for many bulk Si and SOI circuits from the 20-90 nm technology nodes to quantify how much low-energy protons (LEPs) can contribute to the total on-orbit single-event upset (SEU) rate. Every effort was made to predict LEP error rates that are conservatively high; even secondary protons generated in the spacecraft shielding have been included in the analysis. Across all the environments and circuits investigated, and when operating within 10% of the nominal operating voltage, LEPs were found to increase the total SEU rate to up to 4.3 times as high as it would have been in the absence of LEPs. Therefore, the best approach to account for LEP effects may be to calculate the total error rate from high-energy protons and heavy ions, and then multiply it by a safety margin of 5. If that error rate can be tolerated then our findings suggest that it is justified to waive LEP tests in certain situations. Trends were observed in the LEP angular responses of the circuits tested. As a result, grazing angles were the worst case for the SOI circuits, whereas the worst-case angle was at or near normal incidence for the bulk circuits.

  8. The contribution of low-energy protons to the total on-orbit SEU rate

    DOE PAGES

    Dodds, Nathaniel Anson; Martinez, Marino J.; Dodd, Paul E.; ...

    2015-11-10

    Low- and high-energy proton experimental data and error rate predictions are presented for many bulk Si and SOI circuits from the 20-90 nm technology nodes to quantify how much low-energy protons (LEPs) can contribute to the total on-orbit single-event upset (SEU) rate. Every effort was made to predict LEP error rates that are conservatively high; even secondary protons generated in the spacecraft shielding have been included in the analysis. Across all the environments and circuits investigated, and when operating within 10% of the nominal operating voltage, LEPs were found to increase the total SEU rate to up to 4.3 timesmore » as high as it would have been in the absence of LEPs. Therefore, the best approach to account for LEP effects may be to calculate the total error rate from high-energy protons and heavy ions, and then multiply it by a safety margin of 5. If that error rate can be tolerated then our findings suggest that it is justified to waive LEP tests in certain situations. Trends were observed in the LEP angular responses of the circuits tested. As a result, grazing angles were the worst case for the SOI circuits, whereas the worst-case angle was at or near normal incidence for the bulk circuits.« less

  9. Fault-tolerant VHDL descriptions: a case study for SEU-tolerant digital library

    NASA Astrophysics Data System (ADS)

    Tomczak, M.; Swiercz, B.; Napieralski, A.

    2006-10-01

    This paper presents a new cost-effective method of designing Single Event Upset (SEU)-tolerant digital systems based on Commercial-Off-The-Shelf (COTS) Field-Programmable-Gate-Array (FPGA) devices. The project was carried out in cooperation of Technical University of Lodz (TUL) with Deutsches Elektronen-Synchrotron (DESY). DESY is a high-energy particle physics research centre, located in Hamburg, Germany, and has been chosen as a home site for a new generation particle collider - X-Ray Free Electron Laser (X-FEL) accelerator. A need of implementing digital control systems inside accelerators main tunnel, brought a new hardware approach to low-cost design reliable compex circuits with respect to Single Event Effects (SEEs). The goal was to develop a high performance method without modifications in the FPGA architecture and without high area penalties. A SEU-tolerant, digital library has been created. From basic gates, through combinational and sequential cells to some more sophisticated units like memory blocks, code converters or arithmetical functions cells, in all elements upset detection and mitigation schemes have been implemented. The library was described in Very High Speed Integrated Circuit Hardware Description Language (VHDL).

  10. The impact of software and CAE tools on SEU in field programmable gate arrays

    NASA Astrophysics Data System (ADS)

    Katz, R.; Wang, J.; McCollum, J.; Cronquist, B.

    1999-12-01

    Field programmable gate array (FPGA) devices, heavily used in spacecraft electronics, have grown substantially in size over the past few years, causing designers to work at a higher conceptual level, with computer aided engineering (CAE) tools synthesizing and optimizing the logic from a description. It is shown that the use of commercial-off-the-shelf (COTS) CAE tools can produce unreliable circuit designs when the device is used in a radiation environment and a flip-flop is upset. At a lower level, software can be used to improve the SEU performance of a flip-flop, exploiting the configurable nature of FPGA technology and on-chip delay, parasitic resistive, and capacitive circuit elements.

  11. Using Pipelined XNOR Logic to Reduce SEU Risks in State Machines

    NASA Technical Reports Server (NTRS)

    Le, Martin; Zheng, Xin; Katanyoutant, Sunant

    2008-01-01

    Single-event upsets (SEUs) pose great threats to avionic systems state machine control logic, which are frequently used to control sequence of events and to qualify protocols. The risks of SEUs manifest in two ways: (a) the state machine s state information is changed, causing the state machine to unexpectedly transition to another state; (b) due to the asynchronous nature of SEU, the state machine's state registers become metastable, consequently causing any combinational logic associated with the metastable registers to malfunction temporarily. Effect (a) can be mitigated with methods such as triplemodular redundancy (TMR). However, effect (b) cannot be eliminated and can degrade the effectiveness of any mitigation method of effect (a). Although there is no way to completely eliminate the risk of SEU-induced errors, the risk can be made very small by use of a combination of very fast state-machine logic and error-detection logic. Therefore, one goal of two main elements of the present method is to design the fastest state-machine logic circuitry by basing it on the fastest generic state-machine design, which is that of a one-hot state machine. The other of the two main design elements is to design fast error-detection logic circuitry and to optimize it for implementation in a field-programmable gate array (FPGA) architecture: In the resulting design, the one-hot state machine is fitted with a multiple-input XNOR gate for detection of illegal states. The XNOR gate is implemented with lookup tables and with pipelines for high speed. In this method, the task of designing all the logic must be performed manually because no currently available logic synthesis software tool can produce optimal solutions of design problems of this type. However, some assistance is provided by a script, written for this purpose in the Python language (an object-oriented interpretive computer language) to automatically generate hardware description language (HDL) code from state

  12. Effects of Temperature and Supply Voltage on SEU- and SET-Induced Errors in Bulk 40-nm Sequential Circuits

    NASA Astrophysics Data System (ADS)

    Chen, R. M.; Diggins, Z. J.; Mahatme, N. N.; Wang, L.; Zhang, E. X.; Chen, Y. P.; Zhang, H.; Liu, Y. N.; Narasimham, B.; Witulski, A. F.; Bhuva, B. L.; Fleetwood, D. M.

    2017-08-01

    The single-event sensitivity of bulk 40-nm sequential circuits is investigated as a function of temperature and supply voltage. An overall increase in SEU cross section versus temperature is observed at relatively high supply voltages. However, at low supply voltages, there is a threshold temperature beyond which the SEU cross section decreases with further increases in temperature. Single-event transient induced errors in flip-flops also increase versus temperature at relatively high supply voltages and are more sensitive to temperature variation than those caused by single-event upsets.

  13. Experimental determination of single-event upset (SEU) as a function of collected charge in bipolar integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Malone, C. J.; Smith, L. S.

    1984-01-01

    Single-Event Upset (SEU) in bipolar integrated circuits (ICs) is caused by charge collection from ion tracks in various regions of a bipolar transistor. This paper presents experimental data which have been obtained wherein the range-energy characteristics of heavy ions (Br) have been utilized to determine the cross section for soft-error generation as a function of charge collected from single-particle tracks which penetrate a bipolar static RAM. The results of this work provide a basis for the experimental verification of circuit-simulation SEU modeling in bipolar ICs.

  14. Validity of Using a Fixed Analog Input for Evaluating the SEU Sensitivity of a Flash Analog-to-Digital Converter

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; Campbell, Arthur B.; Sternberg, Andrew; Massengill, Lloyd; McMorrow, Dale; Dyer, Clive

    2003-01-01

    The SEU rate in a flash ADC (AD9058) on board a space experiment varied by more than an order of magnitude, depending on the input. A pulsed laser aided in elucidating the reasons, which were found to be the result of the unique design of the AD9058.

  15. IBM powerPC 405 SEU mitigation using processor voting techniques in Xilinx Virtex-I1 pro FPGA

    NASA Technical Reports Server (NTRS)

    Wang, Mandy W.; Bolotin, Gary S.

    2004-01-01

    Not until recently, Xilinx has developed a new field programmable gate array (FPGA) device family, Virtex-I1 Pro. In this single device, not only dies it have density logic cells (3K to125K), gigabit connectivity, on chip memory, digital clock management, but also it can have up to four IBM PowerPC 405 Processor hard cores, running up to 400MHz and 633 Mbps. To utilize this cutting edge device in space applications, a few Single Event Upset (SEU) mitigation techniques need to be implemented to a design for the device. At Jet Propulsion Laboratory (JPL), we have successfully demonstrated the feasibility of running multiple processors running in a lock step fashion to accomplish SEU mitigation and fault tolerance.

  16. IBM powerPC 405 SEU mitigation using processor voting techniques in Xilinx Virtex-I1 pro FPGA

    NASA Technical Reports Server (NTRS)

    Wang, Mandy W.; Bolotin, Gary S.

    2004-01-01

    Not until recently, Xilinx has developed a new field programmable gate array (FPGA) device family, Virtex-I1 Pro. In this single device, not only dies it have density logic cells (3K to125K), gigabit connectivity, on chip memory, digital clock management, but also it can have up to four IBM PowerPC 405 Processor hard cores, running up to 400MHz and 633 Mbps. To utilize this cutting edge device in space applications, a few Single Event Upset (SEU) mitigation techniques need to be implemented to a design for the device. At Jet Propulsion Laboratory (JPL), we have successfully demonstrated the feasibility of running multiple processors running in a lock step fashion to accomplish SEU mitigation and fault tolerance.

  17. Pressure/temperature sensitive inorganic phosphors. [La/sub 2/O/sub 2/S:Eu

    SciTech Connect

    Seals, W.O.; Offen, H.W.; Turley, W.D.

    1987-01-01

    Kistler gauges are presently used to monitor pressures generated in various types of experimental tests. When a one-gallon container of stores liquid propellant was impacted by a shaped charge, hydraulic pressures in excess of 100,000 psi were produced. This destroyed the gauges. A class of inorganic phosphors, including rare earth-doped lanthanum oxysulfide (La/sub 2/O/sub 2/S:Eu) and yittrium oxysulfide (Y/sub 2/O/sub 2/S:Eu), show spectral emission characteristics that are strongly pressure dependent. The intensity of the emission lines and fluorescence decay time if individual emission lines show pressure dependence in the range of several kbar to greater than 100 kbar. These properties suggest that these phosphors could be applied as remotely operated pressure transducers. In addition phosphors show temperature dependence. This paper discusses the potential of inorganic phosphors to measure high pressure and also examines temperature effects. 5 refs., 7 figs

  18. Fiber optic temperature sensor using a Y{sub 2}O{sub 2}S:Eu thermographic phosphor

    SciTech Connect

    Smith, T.V.; Smith, D.B.

    1993-09-01

    This report details the development and testing of a thermographic-phosphor-based fiber-optic temperature sensor. The sensor is constructed by removing a region of the fiber jacket and cladding, then coating the exposed core with yttrium oxysulfide doped with a europium activator (Y{sub 2}O{sub 2}S:Eu). When photoexcited, the europium in the host lattice emits a sharp-line fluorescence spectrum that is characteristic of the temperature of the host crystal lattice. By measuring fluorescence lifetimes, we can deduce the temperature of an optical fiber that is in thermal contact with the fiber. Two different distributions of Y{sub 2}O{sub 2}S:Eu in the cladding region were evaluated with regard to light coupling efficiency. Theoretical waveguide calculations indicate that a thin core/cladding boundary distribution of Y{sub 2}O{sub 2}S:Eu couples light more efficiently into the cores guided modes than does a bulk distribution of phosphor in the cladding. The sensor tests showed reproducible response from 20 to 180 degrees Celsius. This technique has several advantages over other fiber optic temperature sensing techniques: the temperature measurement is independent of the strain applied to the fiber; the measurements are potentially accurate to within half a degree centigrade; the sensor allows temperature to be measured at precise locations; and the method doesn`t preclude the use of the fiber for the simultaneous measurement of other parameters.

  19. A new approach to the analysis of SEU and SEL data to obtain the sensitive volume thickness

    SciTech Connect

    Barak, J.; Levinson, J.; Akkerman, A.; Zentner, A.; David, D.; Even, O.; Lifshitz, Y.; Hass, M.; Victoria, M.

    1996-06-01

    It is proposed to use short-range ions (along with long-range ions) to obtain the thickness of the sensitive volume, d, and the SEU and SEL cross sections vs the energy deposited in this volume, {sigma}{sub ion}({var_epsilon}). These {sigma}{sub ion}({var_epsilon}) and d can be used for calculating the proton induced cross sections {sigma}{sub p}. A study of HM65162 demonstrates this method. The calculated {sigma}{sub p} is in good agreement with the experimental {sigma}{sub p}.

  20. Tree Diversity and Dynamics of the Forest of Seu Nico, Viçosa, Minas Gerais, Brazil.

    PubMed

    Gastauer, Markus; Leyh, Werner; Meira-Neto, João A A

    2015-01-01

    To understand future changes in community composition due to global changes, the knowledge about forest community dynamics is of crucial importance. To improve our understanding about processes and patterns involved in maintaining species rich Neotropical ecosystems, we provide here a dataset from the one hectare Forest of Seu Nico (FSN) Dynamics Plot from Southeastern Brazil. We report diameter at breast height, basal area and height measurements of 2868 trees and treelets identified from two census spanning over a nine-year period. Furthermore, soil properties and understory light availability of all 100 10 x 10m subplots from the one hectare FSN Dynamics Plot during the second census are given.

  1. Measurement of SEU cross sections in the CDF SVX3 ASIC using 63 MeV protons

    NASA Astrophysics Data System (ADS)

    Grim, G. P.; Bishai, M.; Gay, C.; Hill, C.; Nahn, S.; Pellett, D. E.; Pope, G.; Shepard, P. F.; Slaughter, A. J.; Webster, W. C., III

    2000-06-01

    The single event upset (SEU) cross section has been measured for 63 MeV protons incident on static memory cells in the CDF SVX3 pipelined silicon strip readout ASIC. The device was fabricated in the Honeywell 0.8 μm RICMOS IV bulk process, and contains a number of cells with minimum gate length transistors to control the mode of operation of the chip. Cross sections per cell of (4.4±1.8)×10 -16 cm2, (2.1±0.7)×10 -15 cm2, and (3.9±0.9)×10 -15 cm2 were measured for angles of incidence of 0°, 45°, and 80°, respectively, for cells with 0.8 μm gate length. The SVX3 SEU rate in Run II at the Fermilab Tevatron was estimated to be sufficiently low that it would not affect the performance of the CDF Silicon Tracker.

  2. Spherical Lu2O2S:Eu3+ micro/nano-structure: Controlled synthesis and luminescence properties

    NASA Astrophysics Data System (ADS)

    Zhang, Bowen; Zou, Haifeng; Dai, Yunzhi; Guan, Hongxia; Song, Yanhua; Zheng, Keyan; Zhou, Xiuqing; Shi, Zhan; Sheng, Ye

    2017-02-01

    Monodisperse and uniform Lu2O2S:Eu3+ luminescent spheres have been successfully synthesized through a facile hydrothermal method followed by a subsequent calcination process. The sizes of the spheres can be tuned in the range of 65 nm-295 nm by only changing the pH value of the system. It is indicated that the luminescence properties of the spherical phosphors were strongly influenced by size of the spheres. Such a size-sensitive luminescence property was interpreted from the structures of the spheres, including the degree of crystallinity, band gap energy, crystal field symmetry around Eu3+. We expected that this study not only can provide important information for size-controlled synthesis of spherical phosphors, but also can give a reference for exploration of size-dependent luminescence.

  3. A simple algorithm for predicting proton SEU rates in space compared to the rates measured on the CRRES satellite

    SciTech Connect

    Reed, R.A.; McNulty, P.J.; Beauvais, W.J.; Abdel-Kader, W.G. . Dept. of Physics and Astronomy); Stassinopoulos, E.G.; Barth, J.C.L. )

    1994-12-01

    A new simulation code, the Clemson Omnidirectional Spallation Model for Interaction in Circuits (COSMIC), is described and its predictions agree with SEU data from four devices flown as part of the microelectronics package experiment on the CRRES satellite. The code uses CUPID for determining the energy depositions in the sensitive volumes; it allows proton exposures with arbitrary angles of incidence including random omnidirectional exposure; and the user specifies the thickness of shielding on six sides of the sensitive volume. COSMIC is used as part of an algorithm developed to predict the rate proton induced single event upsets occur in the space radiation environment given by AP-8. In testing the algorithm, the position coordinates are taken from the satellite's ephemeris data, but calculations based on position coordinates from orbital codes were also in agreement with the measured values.

  4. Tree Diversity and Dynamics of the Forest of Seu Nico, Viçosa, Minas Gerais, Brazil

    PubMed Central

    Leyh, Werner; Meira-Neto, João A.A.

    2015-01-01

    Abstract Background To understand future changes in community composition due to global changes, the knowledge about forest community dynamics is of crucial importance. To improve our understanding about processes and patterns involved in maintaining species rich Neotropical ecosystems, we provide here a dataset from the one hectare Forest of Seu Nico (FSN) Dynamics Plot from Southeastern Brazil. New information We report diameter at breast height, basal area and height measurements of 2868 trees and treelets identified from two census spanning over a nine-year period. Furthermore, soil properties and understory light availability of all 100 10 x 10m subplots from the one hectare FSN Dynamics Plot during the second census are given. PMID:26312053

  5. Application of SEU imaging for analysis of device architecture using a 25 MeV/u 86Kr ion microbeam at HIRFL

    NASA Astrophysics Data System (ADS)

    Liu, Tianqi; Yang, Zhenlei; Guo, Jinlong; Du, Guanghua; Tong, Teng; Wang, Xiaohui; Su, Hong; Liu, Wenjing; Liu, Jiande; Wang, Bin; Ye, Bing; Liu, Jie

    2017-08-01

    The heavy-ion imaging of single event upset (SEU) in a flash-based field programmable gate array (FPGA) device was carried out for the first time at Heavy Ion Research Facility in Lanzhou (HIRFL). The three shift register chains with separated input and output configurations in device under test (DUT) were used to identify the corresponding logical area rapidly once an upset occurred. The logic units in DUT were partly configured in order to distinguish the registers in SEU images. Based on the above settings, the partial architecture of shift register chains in DUT was imaged by employing the microbeam of 86Kr ion with energy of 25 MeV/u in air. The results showed that the physical distribution of registers in DUT had a high consistency with its logical arrangement by comparing SEU image with logic configuration in scanned area.

  6. Validity of Using a Fixed Analog Input for Evaluating the SEU Sensitivity of a Flash Analog-to-Digita1 Converter

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; Campbell, Arthur; Sternberg, Andrew; Massengill, Lloyd; McMorrow, Dale; Dyer, Clive

    2003-01-01

    The SEU rate in a flash ADC (AD9058) on board a space experiment varied by more than an order of magnitude, depending on the input. A pulsed laser aided in elucidating the reasons, which were found to be the result of the unique design of the AD9058.

  7. Light emission efficiency and imaging performance of Gd{sub 2}O{sub 2}S:Eu powder scintillator under x-ray radiography conditions

    SciTech Connect

    Michail, C. M.; Fountos, G. P.; Liaparinos, P. F.; Kalyvas, N. E.; Valais, I.; Kandarakis, I. S.; Panayiotakis, G. S.

    2010-07-15

    Purpose: To evaluate Gd{sub 2}O{sub 2}S:Eu powder phosphor as a radiographic image receptor and to compare it to phosphors often used in radiography. Gd{sub 2}O{sub 2}S:Eu is nonhygroscopic, emitting red light with decay time close to that of Gd{sub 2}O{sub 2}S:Tb. Methods: The light intensity emitted per unit of x-ray exposure rate (absolute luminescence efficiency) was measured for laboratory prepared screens with coating thicknesses of 33.1, 46.4, 63.1, 78.3, and 139.8 mg/cm{sup 2} and tube voltages ranging from 50 to 140 kVp. Parameters related to image quality such as the modulation transfer function (MTF) and the detective quantum efficiency (DQE) were also experimentally examined. In addition, a previously validated Monte Carlo code was used to estimate intrinsic x-ray absorption and optical properties, as well as the MTF and the Swank factor (I) of the Gd{sub 2}O{sub 2}S:Eu scintillators. Results: Gd{sub 2}O{sub 2}S:Eu light intensity was found higher than that of single CsI:Tl crystal for tube voltages up to 100 kVp. The MTF and the DQE were found to be comparable with those of Gd{sub 2}O{sub 2}S:Tb and CsI:Tl screens. MTF estimated by the Monte Carlo code was found very close to the experimental MTF values. Gd{sub 2}O{sub 2}S:Eu showed peak emission in the wavelength range 620-630 nm. Its emission spectrum was excellently matched to various optical detectors (photodiodes, photocathodes, CCDs, and CMOS) employed in flat panel detectors. Conclusions: Gd{sub 2}O{sub 2}S:Eu is an efficient phosphor potentially well suited to radiography and especially to some digital detectors sensitive to red light.

  8. Effects of target fragmentation on evaluation of LET spectra from space radiation in low-earth orbit (LEO) environment: impact on SEU predictions

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Cucinotta, F. A.; Wilson, J. W.; Badhwar, G. D.; O'Neill, P. M.; Badavi, F. F.

    1995-01-01

    Recent improvements in the radiation transport code HZETRN/BRYNTRN and galactic cosmic ray environmental model have provided an opportunity to investigate the effects of target fragmentation on estimates of single event upset (SEU) rates for spacecraft memory devices. Since target fragments are mostly of very low energy, an SEU prediction model has been derived in terms of particle energy rather than linear energy transfer (LET) to account for nonlinear relationship between range and energy. Predictions are made for SEU rates observed on two Shuttle flights, each at low and high inclination orbit. Corrections due to track structure effects are made for both high energy ions with track structure larger than device sensitive volume and for low energy ions with dense track where charge recombination is important. Results indicate contributions from target fragments are relatively important at large shield depths (or any thick structure material) and at low inclination orbit. Consequently, a more consistent set of predictions for upset rates observed in these two flights is reached when compared to an earlier analysis with CREME model. It is also observed that the errors produced by assuming linear relationship in range and energy in the earlier analysis have fortuitously canceled out the errors for not considering target fragmentation and track structure effects.

  9. Effects of target fragmentation on evaluation of LET spectra from space radiation in low-earth orbit (LEO) environment: impact on SEU predictions

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Cucinotta, F. A.; Wilson, J. W.; Badhwar, G. D.; O'Neill, P. M.; Badavi, F. F.

    1995-01-01

    Recent improvements in the radiation transport code HZETRN/BRYNTRN and galactic cosmic ray environmental model have provided an opportunity to investigate the effects of target fragmentation on estimates of single event upset (SEU) rates for spacecraft memory devices. Since target fragments are mostly of very low energy, an SEU prediction model has been derived in terms of particle energy rather than linear energy transfer (LET) to account for nonlinear relationship between range and energy. Predictions are made for SEU rates observed on two Shuttle flights, each at low and high inclination orbit. Corrections due to track structure effects are made for both high energy ions with track structure larger than device sensitive volume and for low energy ions with dense track where charge recombination is important. Results indicate contributions from target fragments are relatively important at large shield depths (or any thick structure material) and at low inclination orbit. Consequently, a more consistent set of predictions for upset rates observed in these two flights is reached when compared to an earlier analysis with CREME model. It is also observed that the errors produced by assuming linear relationship in range and energy in the earlier analysis have fortuitously canceled out the errors for not considering target fragmentation and track structure effects.

  10. Effects of Target Fragmentation on Evaluation of LET Spectra From Space Radiation in Low-Earth Orbit (LEO) Environment: Impact on SEU Predictions

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Cucinotta, F. A.; Badhwar, G. D.; ONeill, P. M.; Badavi, F. F.

    1995-01-01

    Recent improvements in the radiation transport code HZETRN/BRYNTRN and galactic cosmic ray environmental model have provided an opportunity to investigate the effects of target fragmentation on estimates of single event upset (SEU) rates for spacecraft memory devices. Since target fragments are mostly of very low energy, an SEU prediction model has been derived in terms of particle energy rather than linear energy transfer (LET) to account for nonlinear relationship between range and energy. Predictions are made for SEU rates observed on two Shuttle flights, each at low and high inclination orbit. Corrections due to track structure effects are made for both high energy ions with track structure larger than device sensitive volume and for low energy ions with dense track where charge recombination is important. Results indicate contributions from target fragments are relatively important at large shield depths (or any thick structure material) and at low inclination orbit. Consequently, a more consistent set of predictions for upset rates observed in these two flights is reached when compared to an earlier analysis with CREME model. It is also observed that the errors produced by assuming linear relationship in range and energy in the earlier analysis have fortuitously canceled out the errors for not considering target fragmentation and track structure effects.

  11. Using Classical Reliability Models and Single Event Upset (SEU) Data to Determine Optimum Implementation Schemes for Triple Modular Redundancy (TMR) in SRAM-Based Field Programmable Gate Array (FPGA) Devices

    NASA Technical Reports Server (NTRS)

    Berg, M.; Kim, H.; Phan, A.; Seidleck, C.; LaBel, K.; Pellish, J.; Campola, M.

    2015-01-01

    Space applications are complex systems that require intricate trade analyses for optimum implementations. We focus on a subset of the trade process, using classical reliability theory and SEU data, to illustrate appropriate TMR scheme selection.

  12. Absolute stereostructures of hovenidulciosides A1 and A2, bioactive novel triterpene glycosides from hoveniae semen seu fructus, the seeds and fruit of Hovenia dulcis Thunb.

    PubMed

    Yoshikawa, M; Ueda, T; Muraoka, O; Aoyama, H; Matsuda, H; Shimoda, H; Yamahara, J; Murakami, N

    1995-03-01

    Two bioactive novel triterpene glycosides named hovenidulciosides A1 and A2 have been isolated from a Chinese natural medicine, Hoveniae Semen Seu Fructus, the seeds and fruit of Hovenia dulcis Thunb. (Rhamnaceae). The absolute stereostructures of hovenidulciosides A1 and A2 with a migrated 16,17-seco-dammarane skeleton have been determined on the basis of chemical and physicochemical evidence which included the X-ray crystallographic analysis of the p-bromobenzoate of their common aglycone, hovenidulcigenin A. Hovenidulciosides A1 and A2 exhibited inhibitory activity on the histamine release from rat mast cells induced by compound 48/80 or calcium ionophore A-23187.

  13. In situ synthesis, enhanced luminescence and application in dye sensitized solar cells of Y2O3/Y2O2S:Eu3+ nanocomposites by reduction of Y2O3:Eu3+

    PubMed Central

    Yuan, Guohai; Li, Mingxia; Yu, Mingqi; Tian, Chungui; Wang, Guofeng; Fu, Honggang

    2016-01-01

    Y2O3/Y2O2S:Eu3+ nanocomposites were successfully prepared by reducing Y2O3:Eu3+ nanocrystals. The obtained Y2O3/Y2O2S:Eu3+ nanocomposites not only can emit enhanced red luminescence excited at 338 nm, but also can be used to improve the efficiency of the dye sensitized solar cells, resulting an efficiency of 8.38%, which is a noticeable enhancement of 12% compared to the cell without Y2O3/Y2O2S:Eu3+ nanocomposites. The results of the incident photon to current, dynamic light scattering, and diffuse reflectance spectra indicated that the enhancement of the cell efficiency was mainly related to the light scattering effect of Y2O3/Y2O2S:Eu3+ nanocomposites. As a phosphor powder, the emission at ~615 nm of Y2O3/Y2O2S:Eu3+ was split into two sub-bands. Compared with Y2O3:Eu3+, the 5D0 → 7F0 and 5D0 → 7F1 emissions of Y2O3/Y2O2S:Eu3+ showed a little red-shift. PMID:27872492

  14. In situ synthesis, enhanced luminescence and application in dye sensitized solar cells of Y2O3/Y2O2S:Eu3+ nanocomposites by reduction of Y2O3:Eu3+

    NASA Astrophysics Data System (ADS)

    Yuan, Guohai; Li, Mingxia; Yu, Mingqi; Tian, Chungui; Wang, Guofeng; Fu, Honggang

    2016-11-01

    Y2O3/Y2O2S:Eu3+ nanocomposites were successfully prepared by reducing Y2O3:Eu3+ nanocrystals. The obtained Y2O3/Y2O2S:Eu3+ nanocomposites not only can emit enhanced red luminescence excited at 338 nm, but also can be used to improve the efficiency of the dye sensitized solar cells, resulting an efficiency of 8.38%, which is a noticeable enhancement of 12% compared to the cell without Y2O3/Y2O2S:Eu3+ nanocomposites. The results of the incident photon to current, dynamic light scattering, and diffuse reflectance spectra indicated that the enhancement of the cell efficiency was mainly related to the light scattering effect of Y2O3/Y2O2S:Eu3+ nanocomposites. As a phosphor powder, the emission at ~615 nm of Y2O3/Y2O2S:Eu3+ was split into two sub-bands. Compared with Y2O3:Eu3+, the 5D0 → 7F0 and 5D0 → 7F1 emissions of Y2O3/Y2O2S:Eu3+ showed a little red-shift.

  15. The influence of different species of gases on the luminescent and structural properties of pulsed laser-ablated Y2O2S:Eu3+ thin films

    NASA Astrophysics Data System (ADS)

    Ali, A. G.; Dejene, B. F.; Swart, H. C.

    2016-05-01

    Y2O2S:Eu3+ films have been grown on Si (100) substrates by using a pulsed laser deposition technique. The thin films grown under vacuum, argon and oxygen ambient have been characterized using structural and luminescent measurements. The X-ray diffraction patterns showed mixed phases of cubic and hexagonal crystal structures. The crystallinity of the film deposited in vacuum is poor, but improved significantly in argon and oxygen atmosphere. Similarly, both scanning electron microscopy and atomic force microscopy confirmed that different species of gases affected the morphology of the films. The average band gap of the films calculated from diffuse reflectance spectra using the Kubelka-Munk function was about 4.69 eV. The photoluminescence measurements indicated red emission of Y2O2S:Eu3+ thin films with the most intense peak appearing at 612 nm, which is assigned to the 5 D 0-7 F 2 transition of Eu3+. The intensities of this most intense peak greatly depend on the species of gas with argon having the highest peak. This phosphor has applications in the flat panel displays.

  16. Influence of vacuum upon preparation and luminescence of Si4+ and Ti4+ codoped Gd2O2S:Eu phosphor.

    PubMed

    Wang, Fei; Yang, Bin; Liu, Dachun; Ma, Wenhui; Chen, Xiumin; Dai, Yongnian

    2014-05-21

    As a novel red long afterglow phosphor, Si(4+) and Ti(4+) ion codoped Gd2O2S:Eu phosphor with spherical morphology, sub-micrometer size and narrow particle size distribution was synthesized by solid-state reaction in vacuum. The vacuum synthesis mechanism was determined by thermal analysis. The crystal structure, luminescence properties and mechanisms were investigated respectively by XRD, SEM and fluorescence spectrophotometer. The results show that well-crystallized Gd2O2S:Eu,Si,Ti phosphors are of hexagonal structure which is in agreement with the standard powder peak positions of Gd2O2S hexagonal phase. It displays pure red emission because of the strongest peaks at 627nm and 617nm which are attributed to energy transfer ((5)D0-(7)F2). There is a little blue shift of charge transfer excitation band in the excitation spectra between the bulk and sub-micrometer-sized samples, which may stem from size dependent shift and different lattice distortion in the position of the Eu(3+)-ligand electron transfer absorption/excitation band. To further study the influence of the impurities in Gd2O2S:Eu crystals on crystal growth, the simulated crystal face and its XRD patterns were illustrated. The preferred orientation of crystal growth changed from crystal face (101) to (100) thus to result in different luminescence mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Intrinsically 89Zr-labeled Gd2O2S:Eu nanophosphors with high in vivo stability for dual-modality imaging

    PubMed Central

    Ai, Fanrong; Goel, Shreya; Zhan, Yonghua; Valdovinos, Hector F; Chen, Feng; Barnhart, Todd E; Cai, Weibo

    2016-01-01

    Radioluminescence imaging (RLI) employs high energy particles from radioisotope decay for in situ excitation of selected nanophosphors. Co-injection of radiopharmaceuticals and nanophosphors suffers from suboptimal RL efficiency owing to the large separation between the source and the emitter. In addition, vastly different pharmacokinetic profiles of the two further impede the practical applications of this approach. To overcome the above challenges, chelator-free radiolabeled nanophosphors with excellent RL efficiency and dual-modality imaging capabilities have been proposed. Abundant O2- donors on Gd2O2S:Eu could intrinsically chelate oxophilic radionuclide 89Zr with ~80 % labeling yield. Positron emission tomography demonstrated superb long-term radiostability of [89Zr]Gd2O2S:Eu@PEG nanoparticles in vivo, and a conventional optical imaging system was used to study radiouminescence properties of [89Zr]Gd2O2S:Eu@PEG nanoparticles in vitro and in vivo. PMID:28078029

  18. Charge collection and SEU mechanisms

    NASA Astrophysics Data System (ADS)

    Musseau, O.

    1994-01-01

    In the interaction of cosmic ions with microelectronic devices a dense electron-hole plasma is created along the ion track. Carriers are separated and transported by the electric field and under the action of the concentration gradient. The subsequent collection of these carriers induces a transient current at some electrical node of the device. This "ionocurrent" (single ion induced current) acts as any electrical perturbation in the device, propagating in the circuit and inducing failures. In bistable systems (registers, memories) the stored data can be upset. In clocked devices (microprocessors) the parasitic perturbation may propagate through the device to the outputs. This type of failure only effects the information, and do not degrade the functionally of the device. The purpose of this paper is to review the mechanisms of single event upset in microelectronic devices. Experimental and theoretical results are presented, and actual questions and problems are discussed. A brief introduction recalls the creation of the dense plasma of electron-hole pairs. The basic processes for charge collection in a simple np junction (drift and diffusion) are presented. The funneling-field effect is discussed and experimental results are compared to numerical simulations and semi-empirical models. Charge collection in actual microelectronic structures is then presented. Due to the parasitic elements, coupling effects are observed. Geometrical effects, in densely packed structures, results in multiple errors. Electronic couplings are due to the carriers in excess, acting as minority carriers, that trigger parasitic bipolar transistors. Single event upset of memory cells is discussed, based on numerical and experimental data. The main parameters for device characterization are presented. From the physical interpretation of charge collection mechanisms, the intrinsic sensitivity of various microelectronic technologies is determined and compared to experimental data. Scaling laws and future trends are finally discussed.

  19. An SEU immune logic family

    NASA Technical Reports Server (NTRS)

    Canaris, J.

    1991-01-01

    A new logic family, which is immune to single event upsets, is described. Members of the logic family are capable of recovery, regardless of the shape of the upsetting event. Glitch propagation from an upset node is also blocked. Logic diagrams for an Inverter, Nor, Nand, and Complex Gates are provided. The logic family can be implemented in a standard, commercial CMOS process with no additional masks. DC, transient, static power, upset recovery and layout characteristics of the new family, based on a commercial 1 micron CMOS N-Well process, are described.

  20. Bioactivity-guided fractionation of the triglyceride-lowering component and in vivo and in vitro evaluation of hypolipidemic effects of Calyx seu Fructus Physalis.

    PubMed

    Yang, Yihui; Piao, Xianmei; Zhang, Mingyu; Wang, Xiaodan; Xu, Bing; Zhu, Jiuxin; Fang, Zhiwei; Hou, Yunlong; Lu, Yanjie; Yang, Baofeng

    2012-03-14

    In folklore, some people take the decoction of Calyx seu Fructus Physalis (CSFP) for lowering blood lipids. The present study is designed to evaluate the lipid-lowering activities of CSFP, and search for its pharmacodynamical material. CSFP was extracted by water and 75% ethanol, respectively. The extracts of CSFP for reducing serum lipid levels were evaluated on mouse model of hyperlipidemia. The optimized extract was subjected to the bioactivity-guided fractionation in which the liquid-liquid extraction, collumn chromatography, the in vivo and in vitro models of hyperlipidemia were utilized. The structure of active component was determined by ¹³C-NMR and ¹H-NMR. The 75% ethanol extract of CSFP decreased the serum total cholesterol (TC) and triglyceride (TG) levels in mouse model of hyperlipidemia. Followed a separation process for the 75% ethanol extract of CSFP, the fraction B was proved to be an active fraction for lowering lipid in vivo and in vitro experiments, which could significantly decrease the serum TC and TG levels in mouse model of hyperlipidemia, and remarkably decrease the increase of TG in primary mouse hepatocytes induced by high glucose and the increase of TG in HepG2 cells induced by oleic acid. The fraction B2, isolated from B on bioactivity-guided fractionation, could significantly decrease TG level in HepG2 cells. One compound with the highest content in B2 was isolated and determined as luteolin-7-O-beta-D-glucopyranoside by NMR spectra. It could significantly reduce the TG level in HepG2 cells, and inhibited the accumulation of lipids by oil red O stain. Our results demonstrated that the 75% ethanol extract of CSFP could improve in vitro and in vivo lipid accumulation. Luteolin-7-O-beta-D-glucopyranoside might be a leading pharmacodynamical material of CSFP for lowering lipids.

  1. Bioactivity-guided fractionation of the triglyceride-lowering component and in vivo and in vitro evaluation of hypolipidemic effects of Calyx seu Fructus Physalis

    PubMed Central

    2012-01-01

    Background In folklore, some people take the decoction of Calyx seu Fructus Physalis (CSFP) for lowering blood lipids. The present study is designed to evaluate the lipid-lowering activities of CSFP, and search for its pharmacodynamical material. Methods CSFP was extracted by water and 75% ethanol, respectively. The extracts of CSFP for reducing serum lipid levels were evaluated on mouse model of hyperlipidemia. The optimized extract was subjected to the bioactivity-guided fractionation in which the liquid-liquid extraction, collumn chromatography, the in vivo and in vitro models of hyperlipidemia were utilized. The structure of active component was determined by 13 C-NMR and 1H-NMR. Results The 75% ethanol extract of CSFP decreased the serum total cholesterol (TC) and triglyceride (TG) levels in mouse model of hyperlipidemia. Followed a separation process for the 75% ethanol extract of CSFP, the fraction B was proved to be an active fraction for lowering lipid in vivo and in vitro experiments, which could significantly decrease the serum TC and TG levels in mouse model of hyperlipidemia, and remarkably decrease the increase of TG in primary mouse hepatocytes induced by high glucose and the increase of TG in HepG2 cells induced by oleic acid. The fraction B2, isolated from B on bioactivity-guided fractionation, could significantly decrease TG level in HepG2 cells. One compound with the highest content in B2 was isolated and determined as luteolin-7-O-beta-D-glucopyranoside by NMR spectra. It could significantly reduce the TG level in HepG2 cells, and inhibited the accumulation of lipids by oil red O stain. Conclusion Our results demonstrated that the 75% ethanol extract of CSFP could improve in vitro and in vivo lipid accumulation. Luteolin-7-O-beta-D-glucopyranoside might be a leading pharmacodynamical material of CSFP for lowering lipids. PMID:22413998

  2. Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement.

    PubMed

    Yap, Sook Voon; Ranson, Robert M; Cranton, Wayne M; Koutsogeorgis, Demosthenes

    2008-09-20

    We focus on the development of a remote temperature sensing technology, i.e., an optical laser-based sensor, using thermographic phosphors for medical applications, particularly within an electromagnetically hostile magnetic resonance imaging (MRI) environment. A MRI scanner uses a strong magnetic field and radio waves to generate images of the inside of the body. The quality of the image improves with increasing magnetic resonance; however, the drawback of applying a greater magnetic strength is the inducement of heat into the body tissue. Therefore, monitoring the patient's temperature inside MRI is vital, but until now, a practical solution for temperature measurement did not exist. We show europium doped lanthanum oxysulphide (La(2)O(2)S:Eu) and terbium doped lanthanum oxysulphide (La(2)O(2)S:Tb) are both temperature sensitive to a low temperature range of 10-50 degrees C when under ultraviolet (UV) excitation. The emission spectra and decay time characteristics of these phosphors were demonstrated. The results indicate that La(2)O(2)S:Eu has a quenching rate of 13.7 m degrees C(-1) and 4 m degrees C(-1) at 512 nm and 538 nm, respectively. In addition, La(2)O(2)S:Tb has a lower quenching rate of 4.19 m degrees C(-1) at 548 nm due to its faster decay time.

  3. Decay time characteristics of La2O2S:Eu and La2O2S:Tb for use within an optical sensor for human skin temperature measurement

    SciTech Connect

    Yap, Sook Voon; Ranson, Robert M.; Cranton, Wayne M.; Koutsogeorgis, Demosthenes

    2008-09-20

    We focus on the development of a remote temperature sensing technology, i.e., an optical laser-based sensor, using thermographic phosphors for medical applications, particularly within an electromagnetically hostile magnetic resonance imaging (MRI) environment. A MRI scanner uses a strong magnetic field and radio waves to generate images of the inside of the body. The quality of the image improves with increasing magnetic resonance; however, the drawback of applying a greater magnetic strength is the inducement of heat into the body tissue. Therefore, monitoring the patient's temperature inside MRI is vital, but until now, a practical solution for temperature measurement did not exist. We show europium doped lanthanum oxysulphide (La2O2S:Eu) and terbium doped lanthanum oxysulphide (La2O2S:Tb) are both temperature sensitive to a low temperature range of 10-50 deg. C when under ultraviolet (UV) excitation. The emission spectra and decay time characteristics of these phosphors were demonstrated. The results indicate that La2O2S:Eu has a quenching rate of 13.7 m deg. C{sup -1} and 4 m deg. C{sup -1} at 512 nm and 538 nm, respectively. In addition, La2O2S:Tb has a lower quenching rate of 4.19 m deg. C{sup -1} at 548 nm due to its faster decay time.

  4. The energy transfer phenomena and colour tunability in Y2O2S:Eu(3+)/Dy(3+) micro-fibers for white emission in solid state lighting applications.

    PubMed

    Som, S; Mitra, P; Kumar, Vijay; Kumar, Vinod; Terblans, J J; Swart, H C; Sharma, S K

    2014-07-14

    This paper reports on the structural, optical and photometric characterization of an Eu(3+)/Dy(3+) doped yttrium oxysulfide phosphor (Y2O2S:Eu(3+)/Dy(3+)) for near white emission in solid state lighting. A series of Y2O2S phosphors doped with Eu(3+)/Dy(3+) were prepared by the hydrothermal method. The microstructures of the as-synthesized phosphors were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results reveal that the obtained powder phosphors have a single-phase hexagonal structure and also indicate that the incorporation of the dopants/co-dopants did not affect the crystal structure. The SEM images reveal the morphology of the prepared phosphors as an intense interpenetrating network of interconnected micro-fibers with a diameter of about 0.15 μm. The band gap of the phosphors was calculated from diffuse reflectance spectra using the Kubelka-Munk function. The Eu(3+), Dy(3+) doped and Eu(3+)/Dy(3+) co-doped phosphors illuminated with ultraviolet light showed characteristic red luminescence corresponding to the (5)D0→(7)FJ transitions of Eu(3+) and characteristic blue and yellow luminescence corresponding to the (4)F9/2→(6)H15/2 or (4)F9/2→(6)H13/2 transitions of Dy(3+). The luminescence spectra, the energy transfer efficiency and the decay curves of the phosphors indicated that there exists a strong energy transfer from Dy(3+) to Eu(3+) and this was demonstrated to be a resonant type via a dipole-quadrupole reaction. Furthermore, the critical distance of the Eu(3+) and Dy(3+) ions have also been calculated. By utilizing the principle of energy transfer it was also demonstrated that with an appropriate tuning of the activator content the Y2O2S:Eu(3+)/Dy(3+) phosphors can exhibit a great potential to act as single-emitting component phosphors for white light emission in solid state lighting technology.

  5. VIRTEX-4 VQ static SEU Characterization Summary

    NASA Technical Reports Server (NTRS)

    Allen, Gregory; Swift, Gary; Carmichael, Carl

    2008-01-01

    This report is the result of the combined efforts of members within the Xilinx Radiation Test Consortium (XRTC), sometimes known as the Xilinx SEE Test Consortium. The XRTC is a voluntary association of aerospace entities, including leading aerospace companies, universities and national laboratories, combining resources to characterize reconfigurable FPGAs for aerospace applications. Previous publications of Virtex-4 radiation results are for commercial (non-epitaxial) devices; see, for example, Refs. 1-4. A notable exception is Ref. 5, which presents XRTC upset measurements of storage elements in the PowerPC405s in the XQR4VFX60. This report of upset susceptibility to heavy ions and protons of the static memory elements in the Virtex-4QV family is a direct parallel to the XRTC report on the thin epitaxial devices in the Virtex-2 family released four years ago.

  6. Bioactive saponins and glycosides. IV. Four methyl-migrated 16,17-seco-dammarane triterpene gylcosides from Chinese natural medicine, hoveniae semen seu fructus, the seeds and fruit of Hovenia dulcis THUNB.: absolute stereostructures and inhibitory activity on histamine release of hovenidulciosides A1, A2, B1, and B2.

    PubMed

    Yoshikawa, M; Murakami, T; Ueda, T; Matsuda, H; Yamahara, J; Murakami, N

    1996-09-01

    Four bioactive methyl-migrated 16,17-seco-dammarane type triterpene glycosides called hovenidulciosides A1, A2, B1, and B2 were isolated from a Chinese natural medicine, Hoveniae Semen Seu Fructus, the seeds and fruit of Hovenia dulcis THUNB. (Rhamnaceae) together with hoduloside III and (+)-gallocatechin. The absolute stereostructures of hovenidulciosides A1, A2, B1, and B2 have been elucidated by chemical and physicochemical evidence. All were found to inhibit the histamine release from rat peritoneal exudate cells induced by compound 48/80 and calcium ionophore A-23187.

  7. [Bioactive constituents of Chinese natural medicines. III. Absolute stereostructures of new dihydroflavonols, hovenitins I, II, and III, isolated from hoveniae semen seu fructus, the seed and fruit of Hovenia dulcis THUNB. (Rhamnaceae): inhibitory effect on alcohol-induced muscular relaxation and hepatoprotective activity].

    PubMed

    Yoshikawa, M; Murakami, T; Ueda, T; Yoshizumi, S; Ninomiya, K; Murakami, N; Matsuda, H; Saito, M; Fujii, W; Tanaka, T; Yamahara, J

    1997-02-01

    The methanol-soluble fraction from a Chinese natural medicine Hoveniae Semen Seu Fructus, the seed and fruit of Hovenia dulcis THUNB. (Rhamnaceae) was found to show an inhibitory effect on the alcohol-induced muscular relaxation and a protective activity on the D-galactosamine/lipopolysaccharide or carbon tetrachloride-induced liver injury. Through bioassay-guided separation using a traction performance test, three new dihydrofravonols named hovenitins I, II, and III were isolated from Hoveniae Semen Seu Fructus together with four known flavonoids, (+)-ampelopsin, laricetrin, myricetin, and (+)-gallocatechin. The absolute stereostructures of hovenitins I, II, and III were determined on the basis of chemical and physicochemical evidence to be (2R, 3R)-5,7,4',5'-tetrahydroxy-3'-methoxydihydroflavonol, (2R,3S)-5,7,4',5'-tetrahydroxy-3'-methoxy-dihydroflavonol, and (2R, 3S)-5,7,3',4',5'-pentahydroxydihydro-flavonol, respectively. Hovenitin I and (+)-ampelopsin, both of which were principal ingredients of the active fractions from this natural medicine, were found to show an inhibitory activity on the ethanol-induced muscle relaxation in rats. In addition, hovenitin I showed a protective activity on the liver injury induced by D-galactosamine/lipopolysaccharide or carbon tetrachloride in mice.

  8. The Sustainable Energy Utility (SEU) Model for Energy Service Delivery

    ERIC Educational Resources Information Center

    Houck, Jason; Rickerson, Wilson

    2009-01-01

    Climate change, energy price spikes, and concerns about energy security have reignited interest in state and local efforts to promote end-use energy efficiency, customer-sited renewable energy, and energy conservation. Government agencies and utilities have historically designed and administered such demand-side measures, but innovative…

  9. SEU/SET Tolerant Phase-Locked Loops

    NASA Technical Reports Server (NTRS)

    Shuler, Robert L., Jr.

    2010-01-01

    The phase-locked loop (PLL) is an old and widely used circuit for frequency and phase demodulation, carrier and clock recovery, and frequency synthesis [1]. Its implementations range from discrete components to fully integrated circuits and even to firmware or software. Often the PLL is a highly critical component of a system, as for example when it is used to derive the on-chip clock, but as of this writing no definitive single-event upset (SET)/single-event transient (SET) tolerant PLL circuit has been described. This chapter hopes to rectify that situation, at least in regard to PLLs that are used to generate clocks. Older literature on fault-tolerant PLLs deals with detection of a hard failure, which is recovered by replacement, repair, or manual restart of discrete component systems. Several patents exist along these lines (6349391, 6272647, and 7089442). A newer approach is to harden the parts of a PLL system, to one degree or another, such as by using a voltage-based charge pump or a triple modular redundant (TMR) voted voltage-controlled oscillator (VCO). A more comprehensive approach is to harden by triplication and voting (TMR) all the digital pieces (primarily the divider) of a frequency synthesis PLL, but this still leaves room for errors in the VCO and the loop filter. Instead of hardening or voting pieces of a system, such as a frequency synthesis system (i.e., clock multiplier), we will show how the entire system can be voted. There are two main ways of doing this, each with advantages and drawbacks. We will show how each has advantages in certain areas, depending on the lock acquisition and tracking characteristics of the PLL. Because of this dependency on PLL characteristics, we will briefly revisit the theory of PLLs. But first we will describe the characteristics of voters and their correct application, as some literature does not follow the voting procedure that guarantees elimination of errors. Additionally, we will find that voting clocks is a bit trickier than voting data where an infallible clock is assumed. It is our job here to produce (or recover) that assumed infallible clock!

  10. The Sustainable Energy Utility (SEU) Model for Energy Service Delivery

    ERIC Educational Resources Information Center

    Houck, Jason; Rickerson, Wilson

    2009-01-01

    Climate change, energy price spikes, and concerns about energy security have reignited interest in state and local efforts to promote end-use energy efficiency, customer-sited renewable energy, and energy conservation. Government agencies and utilities have historically designed and administered such demand-side measures, but innovative…

  11. Methods and circuitry for reconfigurable SEU/SET tolerance

    NASA Technical Reports Server (NTRS)

    Shuler, Jr., Robert L. (Inventor)

    2010-01-01

    A device is disclosed in one embodiment that has multiple identical sets of programmable functional elements, programmable routing resources, and majority voters that correct errors. The voters accept a mode input for a redundancy mode and a split mode. In the redundancy mode, the programmable functional elements are identical and are programmed identically so the voters produce an output corresponding to the majority of inputs that agree. In a split mode, each voter selects a particular programmable functional element output as the output of the voter. Therefore, in the split mode, the programmable functional elements can perform different functions, operate independently, and/or be connected together to process different parts of the same problem.

  12. Xilinx Virtex-5QV (V5QV) Independent SEU Data

    NASA Technical Reports Server (NTRS)

    Berg, Melanie D.; LaBel, Kenneth A.; Pellish, Jonathan

    2014-01-01

    This is an independent study to determine the single event destructive and transient susceptibility of the Xilinx Virtex-5QV (SIRF) device. A framework for evaluating complex digital systems targeted for harsh radiation environments such as space is presented.

  13. Defect-sensitivity analysis of an SEU immune CMOS logic family

    NASA Technical Reports Server (NTRS)

    Ingermann, Erik H.; Frenzel, James F.

    1992-01-01

    Fault testing of resistive manufacturing defects is done on a recently developed single event upset immune logic family. Resistive ranges and delay times are compared with those of traditional CMOS logic. Reaction of the logic to these defects is observed for a NOR gate, and an evaluation of its ability to cope with them is determined.

  14. Determination of key parameters of SEU occurrence using 3-D full cell SRAM simulations

    SciTech Connect

    Roche, P.; Palau, J.M.; Bruguier, G.; Tavernier, C.; Ecoffet, R.; Gasiot, J.

    1999-12-01

    A 3-D entire SRAM cell, based on a 0.35-{micro}m current CMOS technology, is simulated in this work with a DEVICE simulator. The transient current, resulting from a heavy ion strike in the most sensitive region of the cell, is studied as a function of the LET value, the cell layout and the ion penetration depth. A definition of the critical charge is proposed and two new methods are presented to compute this basic amount of charge only using SPICE simulations. Numerical applications are performed with two different generations of submicron CMOS technologies, including the determination of the sensitive thicknesses.

  15. Techniques of Microprocessor Testing and SEU (Single Event Upset)-Rate Prediction.

    DTIC Science & Technology

    1986-08-15

    be tested in a simple computer configuration, e.g., single board computer . The proces- sor "self-tests"~ and the result of the self-test can be...register or in the program counter. Following such an event, the single board computer would sometimes lose track of itself, and a catastrophic

  16. SEU tests performed on the digital communication system for LHC cryogenic instrumentation

    NASA Astrophysics Data System (ADS)

    Casas-Cubillos, J.; Faccio, F.; Gomes, P.; Martin, M. A.; Rodriguez-Ruiz, M. A.

    2002-06-01

    The future LHC particle accelerator will use a large number of cryogenic sensors and actuators, most of which are located inside the machine tunnel and therefore in a radiation environment. These elements will communicate through a fieldbus. This paper reports the irradiation study carried out on WorldFIP fieldbus communication system. A digital communication system based on WorldFIP fieldbus protocol has been implemented and single event effects and total ionizing dose radiation tests have been performed on it.

  17. A guideline for heavy ion radiation testing for Single Event Upset (SEU)

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Malone, C.

    1984-01-01

    A guideline for heavy ion radiation testing for single event upset was prepared to assist new experimenters in preparing and directing tests. How to estimate parts vulnerability and select an irradiation facility is described. A broad brush description of JPL equipment is given, certain necessary pre-test procedures are outlined and the roles and testing guidelines for on-site test personnel are indicated. Detailed descriptions of equipment needed to interface with JPL test crew and equipment are not provided, nor does it meet the more generalized and broader requirements of a MIL-STD document. A detailed equipment description is available upon request, and a MIL-STD document is in the early stages of preparation.

  18. UVPROM dosimetry, microdosimetry and applications to SEU and extreme value theory

    NASA Astrophysics Data System (ADS)

    Scheick, Leif Zebediah

    A new method is described for characterizing a device in terms of the statistical distribution of first failures. The method is based on the erasure of a commercial Ultra- Violet erasable Programmable Read Only Memory (UVPROM). The method of readout would be used on a spacecraft or in other restrictive radiation environments. The measurement of the charge remaining on the floating gate is used to determine absorbed dose. The method of determining dose does not require the detector to be destroyed or erased nor does it effect the ability for taking further measurements. This is compared to extreme value theory applied to the statistical distributions that apply to this device. This technique predicts the threshold of Single Event Effects (SEE), like anomalous changes in erasure time in programmable devices due to high microdose energy-deposition events. This technique also allows for advanced non-destructive, screening of a single microelectronic devices for predictable response in a stressful, i.e. radiation, environments.

  19. Single event upset (SEU) of semiconductor devices - A summary of JPL test data

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Price, W. E.; Malone, C. J.

    1983-01-01

    The data summarized describe single event upset (bit-flips) for 60 device types having data storage elements. The data are from 15 acceleration tests with both protons and heavier ions. Tables are included summarizing the upset threshold data and listing the devices tested for heavy ion induced bit-flip and the devices tested with protons. With regard to the proton data, it is noted that the data are often limited to one proton energy, since the tests were usually motivated by the engineering requirement of comparing similar candidate devices for a system. It is noted that many of the devices exhibited no upset for the given test conditions (the maximum fluence and the maximum proton energy Ep are given for these cases). It is believed, however, that some possibility of upset usually exists because there is a slight chance that the recoil atom may receive up to 10 to 20 MeV of recoil energy (with more energy at higher Ep).

  20. Proton irradiation SEU test results for the SEDS MIL-STD-1773 fiber optic data bus: integrated optoelectronics

    NASA Astrophysics Data System (ADS)

    LaBel, Kenneth A.; Stassinopoulos, E. G.; Marshall, Paul W.; Petersen, Ed L.; Dale, Cheryl J.; Crabtree, Christina M.; Stauffer, Craig A.

    1993-09-01

    The Small Explorer Data System (SEDS) is a spaceflight command and data handling system for the small explorer (SMEX) program at Goddard Space Flight Center (GSFC). A key component in this system is the SEDS MIL-STD-1773 Fiber Optic Multiplexed Data Bus. The 1773 bus provides a means of passing telemetry and commands between spacecraft subsystems. This bus is currently being considered for additional spaceflight programs inside and outside of the NASA realm. The SEDS 1773 bus uses integrated optoelectronics as part of its electrical subsystem (or user) to optical interface. Generic proton and heavy ion test results have been previously reported. Herein is presented proton test results for continuing this investigation under actual subsystem interface conditions (MIL-STD-1773) as well as for generic devices using the proton test facilities at University of California, Davis (UCD). This testing was undertaken as a joint effort between NASA/GSFC and the Naval Research Laboratories (NRL).

  1. Effectiveness of Internal vs. External SEU Scrubbing Mitigation Strategies in a Xilinx FPGA: Design, Test, and Analysis

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Poivey C.; Petrick, D.; Espinosa, D.; Lesea, Austin; LaBel, K. A.; Friendlich, M; Kim, H; Phan, A.

    2008-01-01

    We compare two scrubbing mitigation schemes for Xilinx FPGA devices. The design of the scrubbers is briefly discussed along with an examination of mitigation limitations. Proton and Heavy Ion data are then presented and analyzed.

  2. Experience, lessons learned and methodology in the design of space systems to accommodate total dose and SEU effects

    NASA Technical Reports Server (NTRS)

    Trainor, James H.

    1993-01-01

    We now have considerable experience with successfully designing science systems to function properly, even during and after exposure to ionizing radiation approaching one Megarad, and during large solar particle events with substantial high Z fluxes such as the events that happened in August, 1972 and in the fall of 1989. Nevertheless, with changing device dimensions and properties, newer technologies and new applications, new problems arise. Some recent basic research has shed light on these problems and pointed the way to better diagnostic tests. In the case of single event upsets, clearly one cannot always accurately predict upset probabilities simply by knowing the quiescent Linear Energy Transfer (LET) threshold and the asymptotic cross-section of the device.

  3. SEDS MIL-STD-1773 fiber optic data bus: Proton irradiation test results and spaceflight SEU data

    SciTech Connect

    LaBel, K.A.; Stassinopoulos, E.G.; Miller, J.T. ); Marshall, P. ); Dale, C. ); Crabtree, C.M. ); Gates, M.M. )

    1993-12-01

    The Small Explorer Data System (SEDS) was launched in July of 1992 as part of the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) mission. The SEDS utilizes NASA's first MIL-STD-1773 Fiber Optic Multiplexed Data Bus (or 1773 bus) to communicate with other spacecraft subsystems in the space environment. The 1773 bus is the fiber optic version of the MIL-STD-1553 Data Bus, a electronic wire bus used in many avionics applications. The authors present proton test and space flight single event effect data for NASA's first fiber optic data bus. Bit error rate predictions based on a new proton direct ionization model agree well with flight data for proton belt and solar flare effects.

  4. Total-dose and SEU characterization of 0.25 micron CMOS/SOI integrated circuit memory technologies

    SciTech Connect

    Brothers, C.; Pugh, R.; Duggan, P.; Chavez, J.; Schepis, D.; Yee, D.; Wu, S.

    1997-12-01

    Total-dose and single-event-effect radiation characterization of 0.25 micron test macro SRAMs fabricated at IBM`s East Fishkill research foundry in unhardened bulk and unhardened partially-depleted SOI silicon, are reported. The design and fabrication process were optimized for high-performance and short access time using supply voltages of 2.5v for the 64K-bit and 1.8v for the 144K and 288K-bit test macro SRAMs.

  5. Determining the Best-Fit FPGA for a Space Mission: An Analysis of Cost, SEU Sensitivity,and Reliability

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; LaBel, Ken

    2007-01-01

    This viewgraph presentation reviews the selection of the optimum Field Programmable Gate Arrays (FPGA) for space missions. Included in this review is a discussion on differentiating amongst various FPGAs, cost analysis of the various options, the investigation of radiation effects, an expansion of the evaluation criteria, and the application of the evaluation criteria to the selection process.

  6. Co-precipitation synthesis of Y2O2SO4:Eu3+ nanophosphor and comparison of photoluminescence properties with Y2O3:Eu3+ and Y2O2S:Eu3+ nanophosphors

    NASA Astrophysics Data System (ADS)

    Lian, Jingbao; Qin, Hua; Liang, Ping; Liu, Feng

    2015-10-01

    Eu3+ ions activated yttrium oxysulfate (Y2O2SO4:Eu3+) nanophosphor has been successfully synthesized by a co-precipitation method from commercially available Y(NO3)3·6H2O, Eu(NO3)3·6H2O, (NH4)2SO4 and NH3·H2O as the starting materials. Detailed characterizations of the synthetic products were obtained by differential thermal analysis, thermogravimetry and derivative thermogravimetry (DTA-TG-DTG), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results revealed that the precursor was composed of amorphous yttrium hydroxide sulfate when (NH4)2SO4 was introduced in the reaction system. Moreover, the precursor could be converted into pure Y2O2SO4 phase by calcining at 800 °C for 2 h in air and pure Y2O2S phase could be obtained by calcining Y2O2SO4 at 800 °C for 1 h in hydrogen atmosphere. The as-synthesized Y2O2SO4 phosphor particles are quasi-spherical in shape, slight aggregation and about 20-30 nm in size. PL spectra of the Y2O2SO4:Eu3+ nanophosphor under 270 nm ultraviolet (UV) light excitation show a red emission at 620 nm as the most prominent peak, which attributes to the 5D0→7F2 transition of Eu3+ ions. The quenching concentration of Eu3+ ions was 5 mol%, and its corresponding fluorescence lifetime was 1.49 ms according to the linear fitting result. Furthermore, the Y2O3 nanophosphor was synthesized by similar reaction and comparison of PL properties among three kinds of Eu3+ activated nanophosphors was also systematically discussed.

  7. Single event upsets calculated from new ENDF/B-VI proton and neutron data up to 150 MeV

    SciTech Connect

    Chadwick, M.B.; Normand, E.

    1999-06-01

    Single-event upsets (SEU) in microelectronics are calculated from newly-developed silicon nuclear reaction recoil data that extend up to 150 MeV, for incident protons and neutrons. Calculated SEU cross sections are compared with measured data.

  8. SEUSS Integrates Gibberellin Signaling with Transcriptional Inputs from the SHR-SCR-SCL3 Module to Regulate Middle Cortex Formation in the Arabidopsis Root1[OPEN

    PubMed Central

    Gong, Xue; Hong, Jing Han; Chu, Huangwei; Lim, Jun

    2016-01-01

    A decade of studies on middle cortex (MC) formation in the root endodermis of Arabidopsis (Arabidopsis thaliana) have revealed a complex regulatory network that is orchestrated by several GRAS family transcription factors, including SHORT-ROOT (SHR), SCARECROW (SCR), and SCARECROW-LIKE3 (SCL3). However, how their functions are regulated remains obscure. Here we show that mutations in the SEUSS (SEU) gene led to a higher frequency of MC formation. seu mutants had strongly reduced expression of SHR, SCR, and SCL3, suggesting that SEU positively regulates these genes. Our results further indicate that SEU physically associates with upstream regulatory sequences of SHR, SCR, and SCL3; and that SEU has distinct genetic interactions with these genes in the control of MC formation, with SCL3 being epistatic to SEU. Similar to SCL3, SEU was repressed by the phytohormone GA and induced by the GA biosynthesis inhibitor paclobutrazol, suggesting that SEU acts downstream of GA signaling to regulate MC formation. Consistently, we found that SEU mediates the regulation of SCL3 by GA signaling. Together, our study identifies SEU as a new critical player that integrates GA signaling with transcriptional inputs from the SHR-SCR-SCL3 module to regulate MC formation in the Arabidopsis root. PMID:26818732

  9. Studies Of Single-Event-Upset Models

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Smith, L. S.; Soli, G. A.

    1988-01-01

    Report presents latest in series of investigations of "soft" bit errors known as single-event upsets (SEU). In this investigation, SEU response of low-power, Schottky-diode-clamped, transistor/transistor-logic (TTL) static random-access memory (RAM) observed during irradiation by Br and O ions in ranges of 100 to 240 and 20 to 100 MeV, respectively. Experimental data complete verification of computer model used to simulate SEU in this circuit.

  10. The NASA Education Forum at SAO on the Structure and Evolution of the Universe

    NASA Technical Reports Server (NTRS)

    Gould, Roy; Rosendhal, Jeffrey (Technical Monitor)

    2001-01-01

    During the past year the SEU Forum has made significant progress on a number of fronts: (1) the Forum has brought several large education projects close to completion; (2) we have greatly expanded our relationship with the SEU missions and programs; and (3) we have started a significant program to better involve space scientists in education and outreach activities. Among our accomplishments for the past year: (1) completed planning and design for Cosmic Questions, a national traveling exhibition on SEU themes; (2) launched the informal Science Education Resource Directory; (3) Coordinating with the SEU and Origins missions; and (4) promoted scientist-educator partnerships.

  11. Single event upsets in semiconductor devices induced by highly ionising particles.

    PubMed

    Sannikov, A V

    2004-01-01

    A new model of single event upsets (SEUs), created in memory cells by heavy ions and high energy hadrons, has been developed. The model takes into account the spatial distribution of charge collection efficiency over the cell area not considered in previous approaches. Three-dimensional calculations made by the HADRON code have shown good agreement with experimental data for the energy dependence of proton SEU cross sections, sensitive depths and other SEU observables. The model is promising for prediction of SEU rates for memory chips exposed in space and in high-energy experiments as well as for the development of a high-energy neutron dosemeter based on the SEU effect.

  12. Establishing the Empirical Relationship Between Non-Science Majoring Undergraduate Learners' Spatial Thinking Skills and Their Conceptual Astronomy Knowledge. (Spanish Title: Estableciendo Una Relación Empírica Entre el Razonamiento Espacial de los Estudiantes de Graduación de Carreras no Científicas y su Conocimento Conceptual de la Astronomía.) Estabelecendo Uma Relação Empírica Entre o RacioCínio Espacial dos Estudantes de Graduação EM Carreiras Não Científicas e Seu Conhecimento Conceitual da Astronomia

    NASA Astrophysics Data System (ADS)

    Heyer, Inge; Slater, Stephanie J.; Slater, Timothy F.

    2013-12-01

    The astronomy education community has tacitly assumed that learning astronomy is a conceptual domain resting upon spatial thinking skills. As a first step to formally identify an empirical relationship, undergraduate students in a non-major introductory astronomy survey class at a mediumsized, Ph.D. granting, mid-western US university were given pre- and post-astronomy conceptual diagnostics and spatial reasoning diagnostics, Instruments used were the "Test Of Astronomy Standards" and "What Do You Know?" Using only fully matched data for analysis, our sample consisted of 86 undergraduate non-science majors. Students' normalized gains for astronomy surveys were low at .26 and .13 respectively. Students' spatial thinking was measured using an instrument designed specifically for this study. Correlations between the astronomy instruments' pre- to post-course gain scores and the spatial assessment instrument show moderate to strong relationships suggesting the relationship between spatial reasoning and astronomy ability can explain about 25% of the variation in student achievement. La comunidad de educación en astronomía ha supuesto de forma tácita que el aprendizaje de la astronomía consiste en un dominio conceptual fundamentado en el razonamiento espacial. Como un primer paso para identificar formalmente una relación empírica entre estas dos cosas, utilizamos como muestra los estudantes de graduación de carreras no científicas de un curso experimental en una universidad norteamericana del medioeste de porte mediano con programa de Doctorado em curso, en el cual estos estudiantes se sometieron a un diagnóstico de razonamiento espacial y conceptos astronómicos antes e después del mismo. Las herramientas utilizadas fueron el Test Of Astronomy Standards (TOAST) y el cuestionario What do you know? Utilizando solo los datos completamente consistentes para este análisis, nuestra muestra consistió en 86 estudantes de graduación. Las mejoras, depués de normalizadas, en el desempeño de los estudiantes en estos dos asuntos foram pequenas, 0.26 e 0.13 respectivamente. El razonamiento espacial de los estudiantes fue medido utilizando un instrumento específico desarrollado para este trabaljo. Las correlaciones entre los resultados de los tests astronómicos y este instrumento específico, antes y después del curso mostraron una relación entre moderada y fuerte, sugiriendo que la relación entre el razonamiento espacial y el conocimiento astronómico puede explicar hasta un 25% de la variación em el desempeño de los estudiantes. A comunidade da educação em astronomia tem suposto de forma implícita que o aprendizado da astronomia consiste em um domínio conceitual fundamentado no raciocínio espacial. Como um primeiro passo para identificar formalmente uma relação empírica entre estas duas coisas, utilizamos como amostra os estudantes de graduação de carreiras não científicas de um curso exploratório em uma universidade norte-americana do meio-oeste de médio porte com programa de Doutorado em andamento, onde estes estudantes foram submetidos a um diagnóstico de raciocino espacial e conceitos astronômicos antes e depois do mesmo. As ferramentas utilizadas foram o Test Of Astronomy Standards (TOAST) e o questionário What do you know? Utilizando somente dados completamente consistentes para esta análise, nossa amostra consistiu de 86 estudantes de graduação. As melhoras, depois de normalizadas, do desempenho dos estudantes nos dois quesitos foram pequenas, 0.26 e 0.13 respectivamente. O raciocínio espacial dos estudantes foi medido utilizando um instrumento específico desenhado para este trabalho. As correlações entre os resultados dos testes astronômicos e este instrumento específico antes e depois do curso mostraram uma relação entre moderada e forte, sugerindo que a relação entre o raciocínio espacial e o conhecimento astronômico pode explicar até um 25% na variação no desempenho dos estudantes.

  13. In-Flight Observations of Long-Term Single-Event Effect (SEE) Performance on X-ray Timing Explorer (XTE) Solid-state Recorders (SSRs)

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Gee, George; LaBel, Kenneth A.; Barth, Janet L.

    2004-01-01

    We present multi-year Single Event Upset (SEU) flight data on Solid State Recorder (SSR) memories for the X-ray Timing Explorer (XTE) NASA mission. Actual SEU rates are compared to the predicted rates based on ground test data and environment models.

  14. New Mode For Single-Event Upsets

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Smith, Lawrence S.; Soli, George A.; Lo, Roger Y.

    1988-01-01

    Report presents theory and experimental data regarding newly discovered mode for single-event upsets, (SEU's) in complementary metal-oxide/semiconductor, static random-access memories, CMOS SRAM's. SEU cross sections larger than those expected from previously known modes given rise to speculation regarding additional mode, and subsequent cross-section measurements appear to confirm speculation.

  15. The single event upset environment for avionics at high latitude

    SciTech Connect

    Sims, A.J.; Dyer, C.S.; Peerless, C.L. . Space and Communications Dept.); Johansson, K.; Pettersson, H. ); Farren, J. . Harwell Lab.)

    1994-12-01

    Modern avionic systems for civil and military applications are becoming increasingly reliant upon embedded microprocessors and associated memory devices. The phenomenon of single event upset (SEU) is well known in space systems and designers have generally been careful to use SEU tolerant devices or to implement error detection and correction (EDAC) techniques where appropriate. In the past, avionics designers have had no reason to consider SEU effects but is clear that the more prevalent use of memory devices combined with increasing levels of IC integration will make SEU mitigation an important design consideration for future avionic systems. To this end, it is necessary to work towards producing models of the avionics SEU environment which will permit system designers to choose components and EDAC techniques which are based on predictions of SEU rates correct to much better than an order of magnitude. Measurements of the high latitude SEU environment at avionics altitude have been made on board a commercial airliner. Results are compared with models of primary and secondary cosmic rays and atmospheric neutrons. Ground based SEU tests of static RAMs are used to predict rates in flight.

  16. Low energy proton induced single event upset in 65 nm DDR and QDR commercial SRAMs

    NASA Astrophysics Data System (ADS)

    Ye, B.; Liu, J.; Wang, T. S.; Liu, T. Q.; Maaz, K.; Luo, J.; Wang, B.; Yin, Y. N.; Ji, Q. G.; Sun, Y. M.; Hou, M. D.

    2017-09-01

    The single event upset (SEU) response of 65 nm commercial double data rate static random access memory (SRAM) and quad data rate SRAM was investigated by using proton beams with energies in the range of 0.15 MeV to 8.0 MeV. Experimental results show that a significant number of SEU occurrences can be triggered when the energy of incident proton is below 1 MeV. For the low energy protons, the SEU cross section measured in these SRAMs was found to increase with increasing proton energy, attaining a peak value, and then decreases as the proton energy was further increased. While in case of quad data rate SRAMs, it seems that they are more sensitive to SEU occurrences as compared with double data rate SRAMs. The bias voltage and data pattern dependence on SEU cross section induced by the low energy protons were also investigated in this work. In addition, the over-layer thickness of the SRAMs and the impact of degrader use in proton induced SEU test were also analyzed in detail. Monte Carlo simulations results indicate that the use of degrader in case of low energy proton induced SEU test results in a significant reduction of the SEU cross section.

  17. Application of RADSAFE to Model Single Event Upset Response of a 0.25 micron CMOS SRAM

    NASA Technical Reports Server (NTRS)

    Warren, Kevin M.; Weller, Robert A.; Sierawski, Brian; Reed, Robert A.; Mendenhall, Marcus H.; Schrimpf, Ronald D.; Massengill, Lloyd; Porter, Mark; Wilkerson, Jeff; LaBel, Kenneth A.; Adams, James

    2006-01-01

    The RADSAFE simulation framework is described and applied to model Single Event Upsets (SEU) in a 0.25 micron CMOS 4Mbit Static Random Access Memory (SRAM). For this circuit, the RADSAFE approach produces trends similar to those expected from classical models, but more closely represents the physical mechanisms responsible for SEU in the SRAM circuit.

  18. Computational method to estimate Single Event Upset rates in an accelerator environment

    NASA Astrophysics Data System (ADS)

    Huhtinen, M.; Faccio, F.

    2000-08-01

    We present a new method to estimate Single Event Upsets (SEU) in a hadron accelerator environment, which is characterized by a complicated radiation spectrum. Our method is based on first principles, i.e. an explicit generation and transport of nuclear fragments and detailed accounting for energy loss by ionization. However, instead of simulating also the behaviour of the circuit, we use a Weibull fit to experimental heavy-ion SEU data in order to quantify the SEU sensitivity of the circuit. Thus, in principle, we do not need to know details about the circuit and our method is almost free of adjustable parameters - we only need a reasonable guess for the Sensitive Volume (SV) size. We show by a comparison with experimental data that our method predicts the SEU cross sections for protons rather accurately. We then indicate with an example how our method could be applied to predict SEU rates at the forthcoming LHC experiments.

  19. NASA Education Forum at SAO on the Structure and Evolution of the Universe

    NASA Technical Reports Server (NTRS)

    Rosendhal, Jeffrey (Technical Monitor); Gould, Roy R.

    2003-01-01

    NASA's Structure and Evolution of the Universe (SEU) science theme offers an unparalleled opportunity to capture the public's imagination and inspire the next generation of scientific explorers-the generation that will determine America's lead in science and technology in the 21st century. The missions and research programs of SEU science are transporting the public to some of the universe's most exotic destinations: the beginning of time, the edge of space at the entrance to a black hole, and the great cycles of matter and energy that have slowly brought life to the universe. NASA's Office of Space Science (OSS) has put in place an Education and Public Outreach (EPO) initiative designed to do just that. Spanning all of NASA's OSS science themes, the initiative is a far-reaching partnership with the education community. As a result, NASA space science now reaches every avenue of education-from the nation's schools, science museums and planetariums, to libraries, community groups and after-school programs. As a partner in this enterprise, the,SEU Forum has successfully brought SEU science to a large and diverse audience. But this is an ongoing process, and much still needs to be done. Working with our colleagues in the OSS Support Network, and with our partners in the space science and education communities, we look forward to ensuring that the public supports and participates in the great explorations of the SEU theme. Working with the SEU missions and members of the OSS Support Network, the Forum will harness the assets of the SEU science community to: Inform, inspire, and involve the public in the explorations of the SEU science theme. Use the unique resources of the SEU science theme to enhance K-14 science, technology, and mathematics education. Identify and develop high-leverage opportunities for the SEU science community to contribute to education and outreach.

  20. Heavy-ion broad-beam and microprobe studies of single-event upsets in 0.20 um SiGe heterojunction bipolar transistors and circuits.

    SciTech Connect

    Fritz, Karl; Irwin, Timothy J.; Niu, Guofu; Fodness, Bryan; Carts, Martin A.; Marshall, Paul W.; Reed, Robert A.; Gilbert, Barry; Randall, Barbara; Prairie, Jason; Riggs, Pam; Pickel, James C.; LaBel, Kenneth; Cressler, John D.; Krithivasan, Ramkumar; Dodd, Paul Emerson; Vizkelethy, Gyorgy

    2003-09-01

    Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallele-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.

  1. Determination Of LETs Of SRAMs By Use Of A Laser

    NASA Technical Reports Server (NTRS)

    Kim, Quiesup; Mccarty, Kenneth P.; Barnes, Charles E.; Schwartz, Harvey R.; Coss, James R.

    1995-01-01

    Report describes experimental study of use of microelectronic advanced laser scanner (MEALS) to cause single-event upsets (SEUs) in integrated logic circuits. Basic concepts of SEU testing by use of MEALS described in "Laser Scanner Tests for Single-Event Upsets" (NPO-18216), "Single-Event-Upset Laser Scanner With Optical Bias" (NPO-18217), and "More About Laser Scanner Tests for Single-Event Upsets" (NPO-18494). Study part of continuing effort to study SEU effects of ionizing radiation on such circuits and to use MEALS as relatively inexpensive SEU-prescreening laboratory apparatus serving as alternative to heavy-ion acclerator.

  2. Heavy Ion Irradiation Fluence Dependence for Single-Event Upsets of NAND Flash Memory

    NASA Technical Reports Server (NTRS)

    Chen, Dakai; Wilcox, Edward; Ladbury, Raymond; Kim, Hak; Phan, Anthony; Seidleck, Christina; LaBel, Kenneth

    2016-01-01

    We investigated the single-event effect (SEE) susceptibility of the Micron 16 nm NAND flash, and found the single-event upset (SEU) cross section varied inversely with fluence. The SEU cross section decreased with increasing fluence. We attribute the effect to the variable upset sensitivities of the memory cells. The current test standards and procedures assume that SEU follow a Poisson process and do not take into account the variability in the error rate with fluence. Therefore, heavy ion irradiation of devices with variable upset sensitivity distribution using typical fluence levels may underestimate the cross section and on-orbit event rate.

  3. Quality of life of patients with graft-versus-host disease (GvHD) post-hematopoietic stem cell transplantation.

    PubMed

    Proença, Sibéli de Fátima Ferraz Simão; Machado, Celina Mattos; Coelho, Raquel de Castro Figueiredo Pereira; Sarquis, Leila Maria Mansano; Guimarães, Paulo Ricardo Bittencourt; Kalinke, Luciana Puchalski

    2016-01-01

    Assessing the quality of life of adult patients with hematological cancer in the 100 days after transplantation of hematopoietic stem cells and verifying whether the variable graft-versus-host disease (GvHD) is predictive of worse results. An observational correlational and quantitative study with 36 adult participants diagnosed with hematologic cancer who underwent hematopoietic stem cell transplantation from September 2013 to June 2015. The mean age was 37 years, 52.78% were female, and 61.11% were diagnosed with leukemia. Quality of life scores showed a significant impact between pre-transplantation and pre-hospital discharge, and also within the 100 days post-transplantation. The statistical analysis between the scores for the groups with and without GvHD showed a significant difference between the presence of the complication and worse results. Quality of life is altered as a result of hematopoietic stem cells transplantation, especially in patients who have graft-versus-host disease. Avaliar a qualidade de vida de pacientes adultos com câncer hematológico nos 100 dias do transplante de células-tronco hematopoéticas e verificar se a variável doença do enxerto contra o hospedeiro é preditiva de piores resultados. Estudo observacional, correlacional e quantitativo, com 36 participantes adultos, diagnosticados com câncer hematológico que se submeteram ao transplante de células-tronco hematopoéticas de setembro de 2013 a junho de 2015. A média de idade foi 37 anos, 52,78% eram do sexo feminino, e 61,11% com diagnóstico de leucemia. Os escores de qualidade de vida demonstraram impacto significativo entre o pré-transplante e a pré-alta hospitalar e entre os 100 dias pós-transplante. A análise estatística entre os escores dos grupos com e sem doença do enxerto contra o hospedeiro evidenciou significância entre a presença desta complicação e piores resultados. A qualidade de vida é alterada em decorrência do transplante de c

  4. Impact of Temporal Masking of Flip-Flop Upsets on Soft Error Rates of Sequential Circuits

    NASA Astrophysics Data System (ADS)

    Chen, R. M.; Mahatme, N. N.; Diggins, Z. J.; Wang, L.; Zhang, E. X.; Chen, Y. P.; Liu, Y. N.; Narasimham, B.; Witulski, A. F.; Bhuva, B. L.; Fleetwood, D. M.

    2017-08-01

    Reductions in single-event (SE) upset (SEU) rates for sequential circuits due to temporal masking effects are evaluated. The impacts of supply voltage, combinational-logic delay, flip-flop (FF) SEU performance, and particle linear energy transfer (LET) values are analyzed for SE cross sections of sequential circuits. Alpha particles and heavy ions with different LET values are used to characterize the circuits fabricated at the 40-nm bulk CMOS technology node. Experimental results show that increasing the delay of the logic circuit present between FFs and decreasing the supply voltage are two effective ways of reducing SE error rates for sequential circuits for particles with low LET values due to temporal masking. SEU-hardened FFs benefit less from temporal masking than conventional FFs. Circuit hardening implications for SEU-hardened and unhardened FFs are discussed.

  5. Current Radiation Issues for Programmable Elements and Devices

    NASA Technical Reports Server (NTRS)

    Katz, Richard; LaBel, K.; Reed, R.; Wang, J. J.; Cronquist, B.; McCollum, J.; Paolini, W.; Sin, B.; Koga, R.a; Crain, S.; hide

    1998-01-01

    The purpose of this presentation is to discuss the COTS performance, clock upset / single event transient, device configuration upset, antifuse hardening, heavy ion SEU, total dose, proton sensitivities, latchup, and additional information and data.

  6. A simple analytical model of single-event upsets in bulk CMOS

    NASA Astrophysics Data System (ADS)

    Sogoyan, Armen V.; Chumakov, Alexander I.; Smolin, Anatoly A.; Ulanova, Anastasia V.; Boruzdina, Anna B.

    2017-06-01

    During the last decade, multiple new methods of single event upset (SEU) rate prediction for aerospace systems have been proposed. Despite different models and approaches being employed in these methods, they all share relatively high usage complexity and require information about a device that is not always available to an end user. This work presents an alternative approach to estimating SEU cross-section as a function of linear energy transfer (LET) that can be further developed into a method of SEU rate prediction. The goal is to propose a simple, yet physics-based, approach with just two parameters that can be used even in situations when only a process node of the device is known. The developed approach is based on geometrical interpretation of SEU cross-section and an analytical solution to the diffusion problem obtained for a simplified IC topology model. A good fit of the model to the experimental data encompassing 7 generations of SRAMs is demonstrated.

  7. Single-event upset and snapback in silicon-on-insulator devices

    SciTech Connect

    DODD,PAUL E.; SHANEYFELT,MARTY R.; SCHWANK,JAMES R.; HASH,GERALD L.; DRAPER,BRUCE L.; WINOKUR,PETER S.

    2000-02-23

    SEU is studied in SOI transistors and circuits with various body tie structures. The importance of impact ionization effects, including single-event snapback, is explored. Implications for hardness assurance testing of SOI integrated circuits are discussed.

  8. 62 FR 9455 - NASA Advisory Council (NAC), Space Science Advisory Committee (SScAC), Structure and Evolution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    1997-03-03

    ... and Evolution of the Universe Advisory Subcommittee; Meeting AGENCY: National Aeronautics and Space... of the NASA Advisory Council, Space Science Advisory Committee, Structure and Evolution of the... following topics: --Status of Ongoing Missions --Structure and Evolution of Universe (SEU) Strategic...

  9. Evaluation of the Radiation Susceptibility of a 3D NAND Flash Memory

    NASA Technical Reports Server (NTRS)

    Chen, Dakai; Wilcox, Edward; Ladbury, Raymond; Seidleck, Christina; Kim, Hak; Phan, Anthony; LaBel, Kenneth

    2017-01-01

    We evaluated the heavy ion and proton-induced single-event effects (SEE) for a 3D NAND flash. The 3D NAND showed similar single-event upset (SEU) sensitivity to a planar NAND of similar density and performance in the multiple-cell level (MLC) storage mode. However, the single-level-cell (SLC) storage mode of the 3D NAND showed significantly reduced SEU susceptibility. Additionally, the 3D NAND showed less MBU susceptibility than the planar NAND, with reduced number of upset bits per byte and reduced cross sections overall. However, the 3D architecture exhibited angular sensitivities for both base and face angles, reflecting the anisotropic nature of the SEU vulnerability in space. Furthermore, the SEU cross section decreased with increasing fluence for both the 3D NAND and the latest generation planar NAND, indicating a variable upset rate for a space mission. These unique characteristics introduce complexity to traditional ground irradiation test procedures.

  10. NEPP Update of Independent Single Event Upset Field Programmable Gate Array Testing

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; Label, Kenneth; Campola, Michael; Pellish, Jonathan

    2017-01-01

    This presentation provides a NASA Electronic Parts and Packaging (NEPP) Program update of independent Single Event Upset (SEU) Field Programmable Gate Array (FPGA) testing including FPGA test guidelines, Microsemi RTG4 heavy-ion results, Xilinx Kintex-UltraScale heavy-ion results, Xilinx UltraScale+ single event effect (SEE) test plans, development of a new methodology for characterizing SEU system response, and NEPP involvement with FPGA security and trust.

  11. Complementary heterojunction FET technology for space application

    NASA Technical Reports Server (NTRS)

    Larue, George

    1993-01-01

    A 32-bit serial integer multiplier was designed to investigate the yield and performance of complementary heterojunction FET (CHFET) technology. This is the largest reported CHFET logic circuit. The maximum operating frequency was 500 MHz. Very low power dissipation of 3 mW was obtained at 5 MHz operation. Single-event upset (SEU) characteristics of CHFET devices and latches were also measured and indicates the potential for SEU hard circuits for space and military applications.

  12. Transcriptomic Characterization of a Synergistic Genetic Interaction during Carpel Margin Meristem Development in Arabidopsis thaliana

    PubMed Central

    Wynn, April N.; Rueschhoff, Elizabeth E.; Franks, Robert G.

    2011-01-01

    In flowering plants the gynoecium is the female reproductive structure. In Arabidopsis thaliana ovules initiate within the developing gynoecium from meristematic tissue located along the margins of the floral carpels. When fertilized the ovules will develop into seeds. SEUSS (SEU) and AINTEGUMENTA (ANT) encode transcriptional regulators that are critical for the proper formation of ovules from the carpel margin meristem (CMM). The synergistic loss of ovule initiation observed in the seu ant double mutant suggests that SEU and ANT share overlapping functions during CMM development. However the molecular mechanism underlying this synergistic interaction is unknown. Using the ATH1 transcriptomics platform we identified transcripts that were differentially expressed in seu ant double mutant relative to wild type and single mutant gynoecia. In particular we sought to identify transcripts whose expression was dependent on the coordinated activities of the SEU and ANT gene products. Our analysis identifies a diverse set of transcripts that display altered expression in the seu ant double mutant tissues. The analysis of overrepresented Gene Ontology classifications suggests a preponderance of transcriptional regulators including multiple members of the REPRODUCTIVE MERISTEMS (REM) and GROWTH-REGULATING FACTOR (GRF) families are mis-regulated in the seu ant gynoecia. Our in situ hybridization analyses indicate that many of these genes are preferentially expressed within the developing CMM. This study is the first step toward a detailed description of the transcriptional regulatory hierarchies that control the development of the CMM and ovule initiation. Understanding the regulatory hierarchy controlled by SEU and ANT will clarify the molecular mechanism of the functional redundancy of these two genes and illuminate the developmental and molecular events required for CMM development and ovule initiation. PMID:22031826

  13. Low-Energy Proton Testing Methodology

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.; Marshall, Paul W.; Heidel, David F.; Schwank, James R.; Shaneyfelt, Marty R.; Xapsos, M.A.; Ladbury, Raymond L.; LaBel, Kenneth A.; Berg, Melanie; Kim, Hak S.; Phan, Anthony; Friendlich, M.R.; Rodbell, Kenneth P.; Hakey, Mark C.; Dodd, Paul E.; Reed, Robert A.; Weller, Robert A.; Mendenhall, Marcus H.; Sierawski, B.D.

    2009-01-01

    Use of low-energy protons and high-energy light ions is becoming necessary to investigate current-generation SEU thresholds. Systematic errors can dominate measurements made with low-energy protons. Range and energy straggling contribute to systematic error. Low-energy proton testing is not a step-and-repeat process. Low-energy protons and high-energy light ions can be used to measure SEU cross section of single sensitive features; important for simulation.

  14. Contribution to SER Prediction: A New Metric Based on RC Transient Simulations

    NASA Astrophysics Data System (ADS)

    Micolau, G.; Castellani-Coulie, K.; Aziza, H.; Portal, J.-M.

    2012-08-01

    This work focuses on speeding up simulation time of SEU systematic detection in a 90 nm SRAM cell. Simulations were run in order to validate a simplified approach based on the injection of a noise source current at the sensitive node of an analytical RC circuit. Moreover, a new SEU reliability metric, mandatory for reliability studies, is introduced. It is based on based on transient I-V simulations.

  15. Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

    NASA Technical Reports Server (NTRS)

    Croley, D. R.; Garrett, H. B.; Murphy, G. B.; Garrard,T. L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU'S. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU'S, very dose to the 243 observed SEU'S. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU

  16. Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

    NASA Technical Reports Server (NTRS)

    Croley, D. R.; Garrett, H. B.; Murphy, G. B.; Garrard,T. L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU'S. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU'S, very dose to the 243 observed SEU'S. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU

  17. Single event mirroring and sense amplifier designs for enhanced SE tolerance of DRAMs

    SciTech Connect

    Gulati, K.; Massengill, L.W.

    1994-05-01

    This paper investigates the applicability of existing SRAM SEU hardening techniques to conventional CMOS cross-coupled sense amplifiers used in DRAM structures. We propose a novel SEU mirroring concept and implementation for hardening DRAMs to bitline hits. Simulations indicate a 24-fold improvement in critical charge during the sensing state using a 10K T-Resistor scheme and a 28-fold improvement during the highly susceptible high impedance state using 2pF dynamic capacitance coupling.

  18. Transcriptomic characterization of a synergistic genetic interaction during carpel margin meristem development in Arabidopsis thaliana.

    PubMed

    Wynn, April N; Rueschhoff, Elizabeth E; Franks, Robert G

    2011-01-01

    In flowering plants the gynoecium is the female reproductive structure. In Arabidopsis thaliana ovules initiate within the developing gynoecium from meristematic tissue located along the margins of the floral carpels. When fertilized the ovules will develop into seeds. SEUSS (SEU) and AINTEGUMENTA (ANT) encode transcriptional regulators that are critical for the proper formation of ovules from the carpel margin meristem (CMM). The synergistic loss of ovule initiation observed in the seu ant double mutant suggests that SEU and ANT share overlapping functions during CMM development. However the molecular mechanism underlying this synergistic interaction is unknown. Using the ATH1 transcriptomics platform we identified transcripts that were differentially expressed in seu ant double mutant relative to wild type and single mutant gynoecia. In particular we sought to identify transcripts whose expression was dependent on the coordinated activities of the SEU and ANT gene products. Our analysis identifies a diverse set of transcripts that display altered expression in the seu ant double mutant tissues. The analysis of overrepresented Gene Ontology classifications suggests a preponderance of transcriptional regulators including multiple members of the REPRODUCTIVE MERISTEMS (REM) and GROWTH-REGULATING FACTOR (GRF) families are mis-regulated in the seu ant gynoecia. Our in situ hybridization analyses indicate that many of these genes are preferentially expressed within the developing CMM. This study is the first step toward a detailed description of the transcriptional regulatory hierarchies that control the development of the CMM and ovule initiation. Understanding the regulatory hierarchy controlled by SEU and ANT will clarify the molecular mechanism of the functional redundancy of these two genes and illuminate the developmental and molecular events required for CMM development and ovule initiation.

  19. [In vitro effect of the S3Pvac vaccine against cysticercosis in human mononucleate cells].

    PubMed

    Díaz-Orea, María Alicia; Mijares, José Miguel; Arcega, Raúl; Gómez-Conde, Eduardo; Castellanos-Sánchez, Víctor Omar; Briones-Rojas, Rosendo; Flores-Alonso, Juan Carlos; Marín-Briones, Miguel Ángel; Santos-López, Gerardo

    2013-05-01

    Introduccion. La neurocisticercosis (NCC) es una infeccion parasitaria generada por el establecimiento de cisticercos de Taenia solium en el sistema nervioso central. La fase larvaria del parasito tambien afecta al cerdo, que es el huesped intermediario indispensable para la transmision. Por tal motivo, muchos investigadores se han enfocado en identificar antigenos protectores para prevenir la cisticercosis porcina e interrumpir la transmision. Entre ellos figuran los antigenos de la vacuna S3Pvac, constituida por tres peptidos protectores: KETc1, KETc12 y GK1. Objetivo. Evaluar el efecto de los peptidos vacunales KETc1, KETc12 y GK1 en celulas mononucleares de pacientes con NCC e individuos sanos. Sujetos y metodos. Estudio comparativo, prospectivo y transversal. Se analizo la proliferacion y el perfil de citocinas inducidos por los tres peptidos en celulas mononucleares de tres pacientes con NCC activa, 16 pacientes con NCC calcificada y 16 sujetos sanos. Resultados. KETc1 induce bajos niveles de proliferacion en las celulas de los pacientes con NCC activa y controlada, tanto en linfocitos como en monocitos. KETc12 y GK-1 inducen niveles positivos de proliferacion de monocitos en sujetos sanos. Conclusiones. El peptido KETc1 podria usarse como coadyuvante en el tratamiento de los pacientes con NCC activa, ya que indujo una respuesta Th2; y el peptido GK1, como estimulador del monocito/macrofago en inmunizaciones con otras proteinas.

  20. Test results of an ITER relevant FPGA when irradiated with neutrons

    SciTech Connect

    Batista, Antonio J. N.; Santos, Bruno; Fernandes, Ana; Goncalves, Bruno; Leong, Carlos; Teixeira, Joao P.; Ramos, Ana Rita; Santos, Joana P.; Marques, Jose G.

    2015-07-01

    The data acquisition and control instrumentation cubicles room of the ITER tokamak will be irradiated with neutrons during the fusion reactor operation. A Virtex-6 FPGA from Xilinx (XC6VLX365T-1FFG1156C) is used on the ATCA-IO-PROCESSOR board, included in the ITER Catalog of I and C products - Fast Controllers. The Virtex-6 is a re-programmable logic device where the configuration is stored in Static RAM (SRAM), functional data stored in dedicated Block RAM (BRAM) and functional state logic in Flip-Flops. Single Event Upsets (SEU) due to the ionizing radiation of neutrons causes soft errors, unintended changes (bit-flips) to the values stored in state elements of the FPGA. The SEU monitoring and soft errors repairing, when possible, were explored in this work. An FPGA built-in Soft Error Mitigation (SEM) controller detects and corrects soft errors in the FPGA configuration memory. Novel SEU sensors with Error Correction Code (ECC) detect and repair the BRAM memories. Proper management of SEU can increase reliability and availability of control instrumentation hardware for nuclear applications. The results of the tests performed using the SEM controller and the BRAM SEU sensors are presented for a Virtex-6 FPGA (XC6VLX240T-1FFG1156C) when irradiated with neutrons from the Portuguese Research Reactor (RPI), a 1 MW nuclear fission reactor operated by IST in the neighborhood of Lisbon. Results show that the proposed SEU mitigation technique is able to repair the majority of the detected SEU errors in the configuration and BRAM memories. (authors)

  1. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  2. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  3. Feasibility of a neutron detector-dosemeter based on single-event upsets in dynamic random-access memories.

    PubMed

    Phillips, G W; August, R A; Campbell, A B; Nelson, M E; Price, J L; Guardala, N A; Moscovitch, M

    2002-01-01

    The feasibility was investigated of a solid-state neutron detector/dosemeter based on single-event upset (SEU) effects in dynamic random-access memories (DRAMs), commonly used in computer memories. Such a device, which uses a neutron converter material to produce a charged particle capable of causing an upset, would be light-weight, low-power, and could be read simply by polling the memory for bit flips. It would have significant advantages over standard solid-state neutron dosemeters which require off-line processing for track etching and analysis. Previous efforts at developing an SEU neutron detector/dosemeter have suffered from poor response, which can be greatly enhanced by selecting a modern high-density DRAM chip for SEU sensitivity and by using a thin 10B film as a converter. Past attempts to use 10B were not successful because the average alpha particle energy was insufficient to penetrate to the sensitive region of the memory. This can be overcome by removing the surface passivation layer before depositing the 10B film or by implanting 10B directly into the chip. Previous experimental data show a 10(3) increase in neutron sensitivity by chips containing borosilicate glass, which could be used in an SEU detector. The results are presented of simulations showing that the absolute efficiency of an SEU neutron dosemeter can be increased by at least a factor of 1000 over earlier designs.

  4. Single-event-upset sensitivity analysis on low-swing drivers.

    PubMed

    Mahyuddin, Nor Muzlifah; Russell, Gordon

    2014-01-01

    Technology scaling relies on reduced nodal capacitances and lower voltages in order to improve performance and power consumption, resulting in significant increase in layout density, thus making these submicron technologies more susceptible to soft errors. Previous analysis indicates a significant improvement in SEU tolerance of the driver when the bias current is injected into the circuit but results in increase of power dissipation. Subsequently, other alternatives are considered. The impact of transistor sizes and temperature on SEU tolerance is tested. Results indicate no significant changes in Q(crit) when the effective transistor length is increased by 10%, but there is an improvement when high temperature and high bias currents are applied. However, this is due to other process parameters that are temperature dependent, which contribute to the sharp increase in Q(crit). It is found that, with temperature, there is no clear factor that can justify the direct impact of temperature on the SEU tolerance. Thus, in order to improve the SEU tolerance, high bias currents are still considered to be the most effective method in improving the SEU sensitivity. However, good trade-off is required for the low-swing driver in order to meet the reliability target with minimal power overhead.

  5. Heavy-ion induced single-event upset in integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1991-01-01

    The cosmic ray environment in space can affect the operation of Integrated Circuit (IC) devices via the phenomenon of Single Event Upset (SEU). In particular, heavy ions passing through an IC can induce sufficient integrated current (charge) to alter the state of a bistable circuit, for example a memory cell. The SEU effect is studied in great detail in both static and dynamic memory devices, as well as microprocessors fabricated from bipolar, Complementary Metal Oxide Semiconductor (CMOS) and N channel Metal Oxide Semiconductor (NMOS) technologies. Each device/process reflects its individual characteristics (minimum scale geometry/process parameters) via a unique response to the direct ionization of electron hole pairs by heavy ion tracks. A summary of these analytical and experimental SEU investigations is presented.

  6. New insights gained on mechanisms of low-energy proton-induced SEUs by minimizing energy straggle

    DOE PAGES

    Dodds, Nathaniel Anson; Dodd, Paul E.; Shaneyfelt, Marty R.; ...

    2015-12-01

    In this study, we present low-energy proton single-event upset (SEU) data on a 65 nm SOI SRAM whose substrate has been completely removed. Since the protons only had to penetrate a very thin buried oxide layer, these measurements were affected by far less energy loss, energy straggle, flux attrition, and angular scattering than previous datasets. The minimization of these common sources of experimental interference allows more direct interpretation of the data and deeper insight into SEU mechanisms. The results show a strong angular dependence, demonstrate that energy straggle, flux attrition, and angular scattering affect the measured SEU cross sections, andmore » prove that proton direct ionization is the dominant mechanism for low-energy proton-induced SEUs in these circuits.« less

  7. SEE characteristics of small feature size devices by using laser backside testing

    NASA Astrophysics Data System (ADS)

    Guoqiang, Feng; Shipeng, Shangguan; Yingqi, Ma; Jianwei, Han

    2012-01-01

    This paper presents single event upset (SEU) and single event latch-up (SEL) characteristics of small feature size devices by laser backside testing method, which is dedicated to dealing with the increasing metal layers on the front side of integrated circuits. The influence of test data pattern on SEU threshold and cross-section is investigated. The supply current state of micro latch-up for deep sub-micron SRAM is described. The laser energy thresholds were correlated to heavy ion thresholds LET to determine an empirical relationship between laser energy threshold and heavy ion LET. This empirical relationship was used to estimate the equivalent laser LETs for devices fabricated in small feature sizes. Moreover, the SEU of a Power PC CPU fabricated with 90 nm SOI CMOS process has been tested, which indicates that the laser backside method could be used to evaluate SOI small feature size devices.

  8. Pattern dependence in synergistic effects of total dose on single-event upset hardness

    NASA Astrophysics Data System (ADS)

    Guo, Hongxia; Ding, Lili; Xiao, Yao; Zhang, Fengqi; Luo, Yinhong; Zhao, Wen; Wang, Yuanming

    2016-09-01

    The pattern dependence in synergistic effects was studied in a 0.18 μm static random access memory (SRAM) circuit. Experiments were performed under two SEU test environments: 3 MeV protons and heavy ions. Measured results show different trends. In heavy ion SEU test, the degradation in the peripheral circuitry also existed because the measured SEU cross section decreased regardless of the patterns written to the SRAM array. TCAD simulation was performed. TID-induced degradation in nMOSFETs mainly induced the imprint effect in the SRAM cell, which is consistent with the measured results under the proton environment, but cannot explain the phenomena observed under heavy ion environment. A possible explanation could be the contribution from the radiation-induced GIDL in pMOSFETs. Project supported by the National Natural Science Foundation of China (Grant No. U1532261).

  9. New insights gained on mechanisms of low-energy proton-induced SEUs by minimizing energy straggle

    SciTech Connect

    Dodds, Nathaniel Anson; Dodd, Paul E.; Shaneyfelt, Marty R.; Sexton, Frederick W.; Martinez, Marino J.; Black, Jeffrey D.; Marshall, P. W.; Reed, R. A.; McCurdy, M. W.; Weller, R. A.; Pellish, J. A.; Rodbell, K. P.; Gordon, M. S.

    2015-12-01

    In this study, we present low-energy proton single-event upset (SEU) data on a 65 nm SOI SRAM whose substrate has been completely removed. Since the protons only had to penetrate a very thin buried oxide layer, these measurements were affected by far less energy loss, energy straggle, flux attrition, and angular scattering than previous datasets. The minimization of these common sources of experimental interference allows more direct interpretation of the data and deeper insight into SEU mechanisms. The results show a strong angular dependence, demonstrate that energy straggle, flux attrition, and angular scattering affect the measured SEU cross sections, and prove that proton direct ionization is the dominant mechanism for low-energy proton-induced SEUs in these circuits.

  10. Heavy-ion induced single-event upset in integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1991-01-01

    The cosmic ray environment in space can affect the operation of Integrated Circuit (IC) devices via the phenomenon of Single Event Upset (SEU). In particular, heavy ions passing through an IC can induce sufficient integrated current (charge) to alter the state of a bistable circuit, for example a memory cell. The SEU effect is studied in great detail in both static and dynamic memory devices, as well as microprocessors fabricated from bipolar, Complementary Metal Oxide Semiconductor (CMOS) and N channel Metal Oxide Semiconductor (NMOS) technologies. Each device/process reflects its individual characteristics (minimum scale geometry/process parameters) via a unique response to the direct ionization of electron hole pairs by heavy ion tracks. A summary of these analytical and experimental SEU investigations is presented.

  11. Single-event effects in avionics

    SciTech Connect

    Normand, E.

    1996-04-01

    The occurrence of single-event upset (SEU) in aircraft electronics has evolved from a series of interesting anecdotal incidents to accepted fact. A study completed in 1992 demonstrated that SEU`s are real, that the measured in-flight rates correlate with the atmospheric neutron flux, and that the rates can be calculated using laboratory SEU data. Once avionics DEU was shown to be an actual effect, it had to be dealt with in avionics designs. The major concern is in random access memories (RAM`s), both static (SRAM`s) and dynamic (DRAM`s), because these microelectronic devices contain the largest number of bits, but other parts, such as microprocessors, are also potentially susceptible to upset. In addition, other single-event effects (SEE`s), specifically latch-up and burnout, can also be induced by atmospheric neutrons.

  12. Development of a Nuclear Reaction Database on Silicon for Simulation of Neutron-Induced Single-Event Upsets in Microelectronics and its Application

    NASA Astrophysics Data System (ADS)

    Watanabe, Yukinobu; Kodama, Akihiro; Tukamoto, Yasuyuki; Nakashima, Hideki

    2005-05-01

    We have developed a cross-section database for neutron-induced reactions on 28Si in the energy range between 2 MeV and 3 GeV in order to analyze single-event upsets (SEUs) phenomena induced by cosmic-ray neutrons in microelectronic devices. A simplified spherical device model is proposed for simulation of the initial processes of SEUs. The model is applied to SEU cross-section calculations for semiconductor memory devices. The calculated results are compared with measured SEU cross sections and the other simulation result. The dependence of SEU cross sections on incident neutron energy and secondary ions having the most important effects on SEUs are discussed.

  13. Evaluating system for SRAM-based FPGA single event upset rate

    NASA Astrophysics Data System (ADS)

    Wang, Yunlong; Bao, Bin

    2016-09-01

    This paper takes static random-access-memory (SRAM)-based field-programmable-gate-array (FPGA) as the research object. Attention is focused on the configuration memory of this kind of FPGA, and the research has been devoted to the contents of the configuration memory and the configuration circuit to manage its contents. The single event upset (SEU) happening in the configuration memory doesn't lead to a functional failure necessarily. The dynamic SEU is SEU which happens in the configuration memory and causes necessarily function failure. This paper introduces a test method of dynamic SUE rate for the SRAM-based FPGA by designing a FPGA with self-test function.

  14. The single event upset response of the analog devices, ADSP2100A, digital signal processor

    SciTech Connect

    Harboe-Sorensen, R.; Seran, H.; Armbruster, P.; Adams, L. )

    1992-06-01

    This paper presents the results of a radiation evaluation program carried out by ESTEC on the Analog Devices, ADSP2100A, which is a single chip microprocessor optimized for 12.5 Mips Digital Signal Processing (DSP). Single Event Upset/Latch-up (SEU/SEL) testing using Californium-252 was the primary aim of this program, however, accelerator heavy ion and proton SEU/SEL data as well as total ionizing dose data are also presented. The hardware design and software used will be described and details of the various tests and test facilities will be given. Finally, the authors report on the use of the SEU data for the calculation of expected in-orbit upset rates using the CREME suite of programs.

  15. Radiation-Hardened Electronics for Advanced Communications Systems

    NASA Technical Reports Server (NTRS)

    Whitaker, Sterling

    2015-01-01

    Novel approach enables high-speed special-purpose processors Advanced reconfigurable and reprogrammable communication systems will require sub-130-nanometer electronics. Legacy single event upset (SEU) radiation-tolerant circuits are ineffective at speeds greater than 125 megahertz. In Phase I of this project, ICs, LLC, demonstrated new base-level logic circuits that provide SEU immunity for sub-130-nanometer high-speed circuits. In Phase II, the company developed an innovative self-restoring logic (SRL) circuit and a system approach that provides high-speed, SEU-tolerant solutions that are effective for sub-130-nanometer electronics scalable to at least 22-nanometer processes. The SRL system can be used in the design of NASA's next-generation special-purpose processors, especially reconfigurable communication processors.

  16. Single event upsets of spacecraft microelectronics exposed to solar cosmic rays.

    PubMed

    Kuznetsov, N V; Nymmik, R A

    1996-11-01

    The technique for evaluating the SEU rate induced by solar particle incidence on spacecraft microelectronics is described, including the contributions from the primary (heavy ion-induced) and secondary proton-induced) SEU mechanisms. The technique is based on original computational models for solar particle energy spectra and for SEU occurrence in electronics. The technique was used to analyze the data of the TDRS-1 Fairchild 93L422 IC exposed to protons and ions during the solar cosmic ray event of September-October 1989. The analysis included the distribution of the microcircuit shielding. A strong dependence of solar proton-to-ion ratio on the shielding thickness was indicated by the calculations.

  17. Analysis of radiation induced effects in high-density commercial memories on-board Alsat-1: The impact of extreme solar particle events

    NASA Astrophysics Data System (ADS)

    Bentoutou, Youcef; Bensikaddour, El-Habib

    2015-06-01

    This paper presents a long-term study on radiation effects in non-hardened high density memory devices operating within the main on-board computer system of the Algerian microsatellite Alsat-1 in Low Earth Orbit (LEO). A statistical analysis of single-event upset (SEU) activity is presented for commercial SRAM devices, and their response to extreme solar events shows SEU rate significant increases correlated with high-energy protons (E > 100 MeV). Ground based neutron monitor data are used to illustrate the long-term correlation between galactic cosmic rays and Alsat-1 upsets. The short-term effects of energetic solar particles are illustrated with space environment data from GOES-11. The Alsat-1 observed SEU rates are compared to the predicted rates based on ground test data and environment models. The prediction results are in good agreement with in-flight data.

  18. Light emission efficiency and imaging performance of Gd2O2S: Eu powder scintillator under x-ray radiography conditions.

    PubMed

    Michail, C M; Fountos, G P; Liaparinos, P F; Kalyvas, N E; Valais, I; Kandarakis, I S; Panayiotakis, G S

    2010-07-01

    To evaluate Gd2O2S:Eu powder phosphor as a radiographic image receptor and to compare it to phosphors often used in radiography. Gd2O2S:Eu is nonhygroscopic, emitting red light with decay time close to that of Gd2O2S:Tb. The light intensity emitted per unit of x-ray exposure rate (absolute luminescence efficiency) was measured for laboratory prepared screens with coating thicknesses of 33.1, 46.4, 63.1, 78.3, and 139.8 mg/cm2 and tube voltages ranging from 50 to 140 kVp. Parameters related to image quality such as the modulation transfer function (MTF) and the detective quantum efficiency (DQE) were also experimentally examined. In addition, a previously validated Monte Carlo code was used to estimate intrinsic x-ray absorption and optical properties, as well as the MTF and the Swank factor (I) of the Gd2O2S:Eu scintillators. Gd2O2S:Eu light intensity was found higher than that of single CsI:T1 crystal for tube voltages up to 100 kVp. The MTF and the DQE were found to be comparable with those of Gd2O2S:Tb and CsI:T1 screens. MTF estimated by the Monte Carlo code was found very close to the experimental MTF values. Gd2O2S:Eu showed peak emission in the wavelength range 620-630 nm. Its emission spectrum was excellently matched to various optical detectors (photodiodes, photocathodes, CCDs, and CMOS) employed in flat panel detectors. Gd2O2S:Eu is an efficient phosphor potentially well suited to radiography and especially to some digital detectors sensitive to red light.

  19. Reprogrammable field programmable gate array with integrated system for mitigating effects of single event upsets

    NASA Technical Reports Server (NTRS)

    Ng, Tak-kwong (Inventor); Herath, Jeffrey A. (Inventor)

    2010-01-01

    An integrated system mitigates the effects of a single event upset (SEU) on a reprogrammable field programmable gate array (RFPGA). The system includes (i) a RFPGA having an internal configuration memory, and (ii) a memory for storing a configuration associated with the RFPGA. Logic circuitry programmed into the RFPGA and coupled to the memory reloads a portion of the configuration from the memory into the RFPGA's internal configuration memory at predetermined times. Additional SEU mitigation can be provided by logic circuitry on the RFPGA that monitors and maintains synchronized operation of the RFPGA's digital clock managers.

  20. Method for characterizing the upset response of CMOS circuits using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Blaes, Brent R. (Inventor); Nixon, Robert H. (Inventor); Soli, George A. (Inventor)

    1995-01-01

    A method for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. A technique utilizing test structures to quickly and inexpensively characterize the SEU sensitivity of standard cell latches intended for use in a space environment. This bench-level approach utilizes alpha particles to induce upsets in a low LET sensitive 4-k bit test SRAM. This SRAM consists of cells that employ an offset voltage to adjust their upset sensitivity and an enlarged sensitive drain junction to enhance the cell's upset rate.

  1. Modeling of single-event upset in bipolar integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1983-01-01

    The results of work done on the quantitative characterization of single-event upset (SEU) in bipolar random-access memories (RAMs) have been obtained through computer simulation of SEU in RAM cells that contain circuit models for bipolar transistors. The models include current generators that emulate the charge collected from ion tracks. The computer simulation results are compared with test data obtained from a RAM in a bipolar microprocessor chip. This methodology is applicable to other bipolar integrated circuit constructions in addition to RAM cells.

  2. Cosmic ray simulation and testing program

    NASA Technical Reports Server (NTRS)

    Kolasinski, W. A.; Koga, R.; King, C. G.; Imamoto, S. I.

    1985-01-01

    Single event upset (SEU) and latchup vulnerabilities were determined for a number of parts of interest to NASA space programs. In cases where a threshold linear energy transfer (LET) for SEU could be measured, an upset rate in a low inclination Space Shuttle orbit was computed. The predicted upset rates are extremely low, except for the devices with LET thresholds below the geomagnetic cutoff for altitude and inclination of the Space Shuttle orbit. While some of the devices do exhibit latchup, the cross sections and threshold LETs are such that the risk associated with flying these devices in low, near equatorial orbits is small if not negligible.

  3. Characterization of radiation effects in 65 nm digital circuits with the DRAD digital radiation test chip

    NASA Astrophysics Data System (ADS)

    Jara Casas, L. M.; Ceresa, D.; Kulis, S.; Miryala, S.; Christiansen, J.; Francisco, R.; Gnani, D.

    2017-02-01

    A Digital RADiation (DRAD) test chip has been specifically designed to study the impact of Total Ionizing Dose (TID) (<1 Grad) and Single Event Upset (SEU) on digital logic gates in a 65 nm CMOS technology. Nine different versions of standard cell libraries are studied in this chip, basically differing in the device dimensions, Vt flavor and layout of the device. Each library has eighteen test structures specifically designed to characterize delay degradation and power consumption of the standard cells. For SEU study, a dedicated test structure based on a shift register is designed for each library. TID results up to 500 Mrad are reported.

  4. Characterization of Saccharomyces uvarum (Beijerinck, 1898) and related hybrids: assessment of molecular markers that predict the parent and hybrid genomes and a proposal to name yeast hybrids.

    PubMed

    Nguyen, Huu-Vang; Boekhout, Teun

    2017-03-03

    The use of the nuclear-DNA re-association technique has led taxonomists to consider Saccharomyces uvarum a synonym of S. bayanus. The latter, however, is not a species but a hybrid harbouring S. eubayanus (Seu) and S. uvarum (Su) sub-genomes with a minor DNA contribution from S. cerevisiae (Sc). To recognize genetically pure lines of S. uvarum and putative interspecies hybrids among so-called S. bayanus strains present in public culture collections, we propose the use of four markers that were defined from the S. bayanus CBS 380T composite genome, namely SeuNTS2 (rDNA), ScMAL31, MTY1 and SuMEL1. S. carlsbergensis CBS 1513 was found similar to S. bayanus except that it carries the SeuMEL1 allele. Different marker combinations revealed that among 33 strains examined only few strains were similar to CBS 380T, but many pure S. uvarum lines and putative Su/Seu-related hybrids occurred. Our results demonstrated that these hybrids were erroneously considered authentic S. bayanus and therefore the varietal state "Saccharomyces bayanus var. uvarum comb. nov. Naumov" is not valid. Our markers constitute a tool to get insights into the genomic makeup of Saccharomyces interspecies hybrids. We also make a proposal to name those hybrids that may also be applicable to other fungal hybrids.

  5. Reliability design of CMOS image sensor for space applications

    NASA Astrophysics Data System (ADS)

    Xie, Ning; Chen, Shijun; Chen, Yongping

    2013-08-01

    In space applications, sensors work in very harsh space environment. Thus the reliability design must be carefully considered. This paper addresses the techniques which effectively increase the reliability of CMOS image sensors. A radiation tolerant pixel design which is implemented in a sun tracker sensor is presented. Measurement results of total dose radiation, SEL, SEU, etc prove the radiation immunity of the sensor.

  6. Temperature Dependence of Single-Event Burnout in N-Channel Power MOSFET’s

    DTIC Science & Technology

    1994-03-15

    The temperature dependence of single-event burnout (SEB) in n-channel power metal-oxide-semiconductor field effect transistors (MOSFETs) is...is shown to agree with the experimental trends. SEU, DMOS, HEXFET, Single-Event- Burnout (SEB), N-Channel MOSFET, Temperature dependence .

  7. Teenage Pregnancy and Sex and Relationship Education: Myths and (Mis)conceptions

    ERIC Educational Resources Information Center

    Vincent, Kerry

    2007-01-01

    This paper explores the role of sex and relationship education (SRE) in reducing teenage pregnancy rates. It critically examines some of the assumptions underlying the emphasis placed on SRE within the teenage pregnancy strategy ( SEU, 1999)--in particular, the view that ignorance of sexual matters plays a key part in teenage conception. An…

  8. Teenage Pregnancy and Sex and Relationship Education: Myths and (Mis)conceptions

    ERIC Educational Resources Information Center

    Vincent, Kerry

    2007-01-01

    This paper explores the role of sex and relationship education (SRE) in reducing teenage pregnancy rates. It critically examines some of the assumptions underlying the emphasis placed on SRE within the teenage pregnancy strategy ( SEU, 1999)--in particular, the view that ignorance of sexual matters plays a key part in teenage conception. An…

  9. Cosmic ray heavy ion LET mapping for aluminum, silicon, and tissue targets

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Barth, J. M.; Jordan, T. M.

    1987-01-01

    Linear energy transfer (LET) values in aluminum, silicon, and tissue targets have been calculated for 31 galactic cosmic ray ion species in eight different units. The values are described for single event upset (SEU) effect assessments or radiobiological evaluations. The data are presented in graphical and tabular form.

  10. Alpha-particle emissivity screening of materials used for semiconductor manufacturing

    NASA Astrophysics Data System (ADS)

    Gordon, Michael; Rodbell, Kenneth

    2015-03-01

    Single-Event Upsets (SEU's) in semiconductor memory and logic devices continue to be a reliability issue in modern CMOS devices. SEU's result from deposited charge in the Si devices caused by the passage of ionizing radiation. With technology scaling, the device area decreases, but the critical charge required to flip bits decreases as well. The interplay between both determines how the SEU rate scales with shrinking device geometries and dimensions. In order to minimize the alpha-particle component of SEU, the radiation in the device environment has to be at the Ultra-Low Alpha (ULA) activity levels, e.g. less than 2 α/khr-cm2. Most detectors have background levels that are significantly larger than that level which makes making these measurements difficult and time consuming. A new class of alpha particle detector, utilizing pulse shape discrimination, is now available which allows one to make measurements quickly with ultra-low detector background. This talk will discuss what is involved in making alpha particle measurements of materials in the ULA activity levels, in terms of calibration, radon adsorption mitigation, the time required for obtaining reasonable statistics and comparisons to other detectors.

  11. Single Event Testing on Complex Devices: Test Like You Fly versus Test-Specific Design Structures

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; LaBel, Kenneth A.

    2014-01-01

    We present a framework for evaluating complex digital systems targeted for harsh radiation environments such as space. Focus is limited to analyzing the single event upset (SEU) susceptibility of designs implemented inside Field Programmable Gate Array (FPGA) devices. Tradeoffs are provided between application-specific versus test-specific test structures.

  12. SEE induced in SRAM operating in a superconducting electron linear accelerator environment

    NASA Astrophysics Data System (ADS)

    Makowski, D.; Mukherjee, Bhaskar; Grecki, M.; Simrock, Stefan

    2005-02-01

    Strong fields of bremsstrahlung photons and photoneutrons are produced during the operation of high-energy electron linacs. Therefore, a mixed gamma and neutron radiation field dominates the accelerators environment. The gamma radiation induced Total Ionizing Dose (TID) effect manifests the long-term deterioration of the electronic devices operating in accelerator environment. On the other hand, the neutron radiation is responsible for Single Event Effects (SEE) and may cause a temporal loss of functionality of electronic systems. This phenomenon is known as Single Event Upset (SEU). The neutron dose (KERMA) was used to scale the neutron induced SEU in the SRAM chips. Hence, in order to estimate the neutron KERMA conversion factor for Silicon (Si), dedicated calibration experiments using an Americium-Beryllium (241Am/Be) neutron standard source was carried out. Single Event Upset (SEU) influences the short-term operation of SRAM compared to the gamma induced TID effect. We are at present investigating the feasibility of an SRAM based real-time beam-loss monitor for high-energy accelerators utilizing the SEU caused by fast neutrons. This paper highlights the effects of gamma and neutron radiations on Static Random Access Memory (SRAM), placed at selected locations near the Superconducting Linear Accelerator driving the Vacuum UV Free Electron Laser (VUVFEL) of DESY.

  13. A radiation-hardened 16/32-bit microprocessor

    SciTech Connect

    Hass, K.J.; Treece, R.K.; Giddings, A.E.

    1989-01-01

    A radiation-hardened 16/32-bit microprocessor has been fabricated and tested. Our initial evaluation has demonstrated that it is functional after a total gamma dose of 5Mrad(Si) and is immune to SEU from Krypton ions. 3 refs., 2 figs.

  14. Evaluation of an Ultra-Low Power Reed Solomon Encoder for NASA's Space Technology 5 Mission

    NASA Technical Reports Server (NTRS)

    Li, K. E.; Xapsos, M. A.; Poivey, C.; LaBel, K. A.; Stone, R. F.; Yeh, P-S.; Gambles, J.; Hass, J.; Maki, G.; Marguia, J.

    2003-01-01

    This viewgraph presentation provides information on radiation tests on encoders intended for a constellation of microsatellites. The encoders use CMOS Ultra-Low Power Radiation Tolerant (CULPRiT) technology. The presentation addresses power consumption, radiation dosage, and Single Event Upset (SEU).

  15. Radiation Hardening of Computers

    NASA Technical Reports Server (NTRS)

    Nichols, D. K.; Smith, L. S.; Zoutendyk, J. A.; Giddings, A. E.; Hewlett, F. W.; Treece, R. K.

    1986-01-01

    Single-event upsets reduced by use of oversize transistors. Computers made less susceptible to ionizing radiation by replacing bipolar integrated circuits with properly designed, complementary metaloxide-semiconductor (CMOS) circuits. CMOS circuit chips made highly resistant to single-event upset (SEU), especially when certain feedback resistors are incorporated. Redesigned chips also consume less power than original chips.

  16. Effect of egg position during three and fourteen days of storage and turning frequency during subsequent incubation on hatchability of broiler hatching eggs.

    PubMed

    Elibol, O; Brake, J

    2008-06-01

    Two experiments were carried out to examine the interaction of egg storage period, egg position during storage, and turning frequency during subsequent incubation on fertile hatchability and embryonic mortality of broiler hatching eggs. Broiler hatching eggs from breeder flocks at 62 and 60 wk of age were stored for either 3 or 14 d at 18 degrees C and 75% RH in either the normal large end up or inverted small end up (SEU) position and then turned either 24 or 96 times daily to 18 d of incubation in 2 experiments. The longer storage period decreased fertile hatchability, whereas storage in the SEU position improved fertile hatchability in both experiments. There was a significant storage position x length of storage period interaction in both experiments due to better fertile hatchability for the SEU eggs stored 14 d but not 3 d. The 96-times turning frequency numerically improved fertile hatchability in both experiments. A significant storage period x turning frequency interaction in experiment 1 was related to a 6.6% increase in fertile hatchability of 14-d stored eggs due to increased turning frequency. A similar numerical increase of 4.9% was observed in experiment 2. These data show that the detrimental effects of a long storage period may be practically ameliorated by either storage in the SEU position or by an increased turning frequency during subsequent incubation.

  17. An Advanced Single Event Upset Tester

    DTIC Science & Technology

    1990-08-01

    Californium -252 and the Fission Process ............................................. 24 TFD Scintillation Theory...cross sections for two energy groups, this technique can be readily extended to finer energy divisions for the californium spectrum. The SEU cross...threshold LET values are in good agreement with the results from accelerator measurements. This californium -based device is quite small and fits onto a

  18. Empirical Modeling Of Single-Event Upset

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Smith, Lawrence S.; Soli, George A.; Thieberger, Peter; Smith, Stephen L.; Atwood, Gregory E.

    1988-01-01

    Experimental study presents examples of empirical modeling of single-event upset in negatively-doped-source/drain metal-oxide-semiconductor static random-access memory cells. Data supports adoption of simplified worst-case model in which cross sectionof SEU by ion above threshold energy equals area of memory cell.

  19. SRAM Based Re-programmable FPGA for Space Applications

    NASA Technical Reports Server (NTRS)

    Wang, J. J.; Sun, J. S.; Cronquist, B. E.; McCollum, J. L.; Speers, T. M.; Plants, W. C.; Katz, R. B.

    1999-01-01

    An SRAM (static random access memory)-based reprogrammable FPGA (field programmable gate array) is investigated for space applications. A new commercial prototype, named the RS family, was used as an example for the investigation. The device is fabricated in a 0.25 micrometers CMOS technology. Its architecture is reviewed to provide a better understanding of the impact of single event upset (SEU) on the device during operation. The SEU effect of different memories available on the device is evaluated. Heavy ion test data and SPICE simulations are used integrally to extract the threshold LET (linear energy transfer). Together with the saturation cross-section measurement from the layout, a rate prediction is done on each memory type. The SEU in the configuration SRAM is identified as the dominant failure mode and is discussed in detail. The single event transient error in combinational logic is also investigated and simulated by SPICE. SEU mitigation by hardening the memories and employing EDAC (error detection and correction) at the device level are presented. For the configuration SRAM (CSRAM) cell, the trade-off between resistor de-coupling and redundancy hardening techniques are investigated with interesting results. Preliminary heavy ion test data show no sign of SEL (single event latch-up). With regard to ionizing radiation effects, the increase in static leakage current (static I(sub CC)) measured indicates a device tolerance of approximately 50krad(Si).

  20. Neutron induced soft errors in CMOS memories under reduced bias

    SciTech Connect

    Hazucha, P.; Svensson, C.; Johansson, K. |

    1998-12-01

    A custom designed 16 kbit CMOS memory was irradiated by 14 MeV neutrons and 100 MeV neutrons. SEU cross sections were evaluated under different supply voltages. The cross section values are compared to those predicted by the BGR model.

  1. LEUNIG_HOMOLOG and LEUNIG perform partially redundant functions during Arabidopsis embryo and floral development.

    PubMed

    Sitaraman, Jayashree; Bui, Minh; Liu, Zhongchi

    2008-06-01

    Transcription corepressors play important roles in animal and plant development. In Arabidopsis (Arabidopsis thaliana), LEUNIG (LUG) and LEUNIG_HOMOLOG (LUH) encode two highly homologous proteins that are similar to the animal and fungal Gro/Tup1-type corepressors. LUG was previously shown to form a putative corepressor complex with another protein, SEUSS (SEU), and to repress the transcription of AGAMOUS in floral organ identity specification. However, the function of LUH is completely unknown. Here, we show that single luh loss-of-function mutants develop normal flowers, but lug; luh double mutants are embryo lethal, uncovering a previously unknown function of LUG and LUH in embryonic development. In addition, luh/+ enhances the floral phenotype of lug, revealing a minor role of LUH in flower development. Functional diversification between LUH and LUG is evidenced by the inability of 35S::LUH overexpression to rescue lug mutants and by the opposite expression trends of LUG and LUH in response to biotic and abiotic stresses. The luh-1 mutation does not enhance the defect of seu in flower development, but LUH could directly interact with SEU in yeast. We propose a model that explains the complex relationships among LUH, LUG, and SEU. As most eukaryotes have undergone at least one round of whole-genome duplication during evolution, gene duplication and functional diversification are important issues to consider in uncovering gene function. Our study provides important insights into the complexity in the relationship between two highly homologous paralogous genes.

  2. Single event effects and laser simulation studies

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Schwartz, H.; Mccarty, K.; Coss, J.; Barnes, C.

    1993-01-01

    The single event upset (SEU) linear energy transfer threshold (LETTH) of radiation hardened 64K Static Random Access Memories (SRAM's) was measured with a picosecond pulsed dye laser system. These results were compared with standard heavy ion accelerator (Brookhaven National Laboratory (BNL)) measurements of the same SRAM's. With heavy ions, the LETTH of the Honeywell HC6364 was 27 MeV-sq cm/mg at 125 C compared with a value of 24 MeV-sq cm/mg obtained with the laser. In the case of the second type of 64K SRAM, the IBM640lCRH no upsets were observed at 125 C with the highest LET ions used at BNL. In contrast, the pulsed dye laser tests indicated a value of 90 MeV-sq cm/mg at room temperature for the SEU-hardened IBM SRAM. No latchups or multiple SEU's were observed on any of the SRAM's even under worst case conditions. The results of this study suggest that the laser can be used as an inexpensive laboratory SEU prescreen tool in certain cases.

  3. BUSFET - A Novel Radiation-Hardened SOI Transistor

    SciTech Connect

    Dodd, P.E.; Draper, B.L.; Schwank, J.R.; Shaneyfelt, M.R.

    1999-02-04

    A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology.

  4. The Education of Refugees in Africa: The Role of Distance and Open Learning.

    ERIC Educational Resources Information Center

    Dodds, Tony

    1988-01-01

    Description of education services to refugees in Africa focuses on three case studies: Institute of In-Service Teacher Training (IITT) in Somalia; Sudan Extension Unit (SEU); and Namibian Extension Unit (NEU) in Angola and Zambia. Highlights include refugee problems, the relevance of distance and open learning approaches, and international…

  5. Empirical Modeling Of Single-Event Upset

    NASA Technical Reports Server (NTRS)

    Zoutendyk, John A.; Smith, Lawrence S.; Soli, George A.; Thieberger, Peter; Smith, Stephen L.; Atwood, Gregory E.

    1988-01-01

    Experimental study presents examples of empirical modeling of single-event upset in negatively-doped-source/drain metal-oxide-semiconductor static random-access memory cells. Data supports adoption of simplified worst-case model in which cross sectionof SEU by ion above threshold energy equals area of memory cell.

  6. 61 FR 67576 - NASA Advisory Council (NAC), Space Science Advisory Committee (SScAC), Structure and Evolution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    1996-12-23

    ... and Evolution of the Universe Advisory Subcommittee; Meeting AGENCY: National Aeronautics and Space... of the NASA Advisory Council, Space Science Advisory Committee, Structure and Evolution of the... includes the following topics: --Status of Ongoing Missions --Structure and Evolution of the Universe (SEU...

  7. The Education of Refugees in Africa: The Role of Distance and Open Learning.

    ERIC Educational Resources Information Center

    Dodds, Tony

    1988-01-01

    Description of education services to refugees in Africa focuses on three case studies: Institute of In-Service Teacher Training (IITT) in Somalia; Sudan Extension Unit (SEU); and Namibian Extension Unit (NEU) in Angola and Zambia. Highlights include refugee problems, the relevance of distance and open learning approaches, and international…

  8. Wideband speech enhancement addition

    NASA Astrophysics Data System (ADS)

    Weiss, M. R.; Aschkenasy, E.

    1981-05-01

    This report describes the completion of the development and construction of a speech enhancement unit (SEU). This is an electronic instrument that automatically detects and attenuates tones, clicks, and wideband random noises that may accompany speech signals that are transmitted, recorded, or reproduced electronically. An earlier version of this device was tested extensively by the Air Force and then was returned to Queens College for modification and completion of the system. During the period that is covered by this report, a number of major changes were made in the SEU, leading to a device that is simpler to use, more effective, and more broadly useful in its intended area or application. Some of the changes that were made in the SEU were aimed at reducing the degree of operator intervention that was required. To this end, the SEU was greatly simplified and made more automatic. The manual Digital Spectrum Shaping (DSS) system and most of the manual controls were removed. A new system was added for adjusting the level of the input signal. It keeps the signal at the level that maximizes the effectiveness of the noise attenuation processes. The INTEL process for attenuating wideband random noise was incorporated into the SEU. To make it possible for the speech enhancement unit to operate in real-time with all processes active, the hardware and software of the system were modified extensively. The MAP was upgraded by adding a second arithmetic processor and a high speed memory. The existing programs and algorithms were rewritten to reduce their execution times. These and the INTEL programs were modified to fully exploit the capabilities of the upgraded MAP.

  9. Single event effect characterization of the mixed-signal ASIC developed for CCD camera in space use

    NASA Astrophysics Data System (ADS)

    Nakajima, Hiroshi; Fujikawa, Mari; Mori, Hideki; Kan, Hiroaki; Ueda, Shutaro; Kosugi, Hiroko; Anabuki, Naohisa; Hayashida, Kiyoshi; Tsunemi, Hiroshi; Doty, John P.; Ikeda, Hirokazu; Kitamura, Hisashi; Uchihori, Yukio

    2013-12-01

    We present the single event effect (SEE) tolerance of a mixed-signal application-specific integrated circuit (ASIC) developed for a charge-coupled device camera onboard a future X-ray astronomical mission. We adopted proton and heavy ion beams at HIMAC/NIRS in Japan. The particles with high linear energy transfer (LET) of 57.9 MeV cm2/mg is used to measure the single event latch-up (SEL) tolerance, which results in a sufficiently low cross-section of σSEL<4.2×10-11 cm2/(Ion×ASIC). The single event upset (SEU) tolerance is estimated with various kinds of species with wide range of energy. Taking into account that a part of the protons creates recoiled heavy ions that have higher LET than that of the incident protons, we derived the probability of SEU event as a function of LET. Then the SEE event rate in a low-earth orbit is estimated considering a simulation result of LET spectrum. SEL rate is below once per 49 years, which satisfies the required latch-up tolerance. The upper limit of the SEU rate is derived to be 1.3×10-3 events/s. Although the SEU events cannot be distinguished from the signals of X-ray photons from astronomical objects, the derived SEU rate is below 1.3% of expected non-X-ray background rate of the detector and hence these events should not be a major component of the instrumental background.

  10. Swift heavy ion induced single event upsets in high density UV-EPROM’s

    NASA Astrophysics Data System (ADS)

    Dahiwale, S. S.; Shinde, N. S.; Kanjilal, D.; Bhoraskar, V. N.; Dhole, S. D.

    2008-04-01

    A few high density UV-EPROM's (32Kb × 8) were irradiated with 5.41 MeV energy α-particles with fluences from 104 to 108 alphas/cm2 and 100 MeV nickel, iodine and silver ions for low fluences between 5 × 107 and 108 ions/cm2. The energy and ion species was selected on the basis of predicted threshold values of linear energy transfer (LET) in silicon. The program which was stored in the memory found to be changed from 0 to 1 and 1 to 0 state, respectively. On the basis of changed states, the cross-sections (σ) were calculated to investigate the single event effects/upsets. No upset was observed in case of α-particle since it has very low LET, but the SEU cross-section found to be more in case of Iodine i.e. 2.29 × 10-3 cm2 than that of nickel, 2.12 × 10-3 cm2 and silver, 2.26 × 10-3. This mainly attributes that LET for iodine is more as compared to silver and nickel ions, which deposits large amount of energy near the sensitive node of memory cell in the form of electron-hole pairs required to change the state. These measured SEU cross-section were also compared with theoretically predicted values along with the Weibull distribution fit to the ion induced experimental SEU data. The theoretical predicted SEU cross-section 3.27 × 10-3 cm2 found to be in good agreement with the measured SEU cross-section.

  11. Redundant single event upset supression system

    DOEpatents

    Hoff, James R.

    2006-04-04

    CMOS transistors are configured to operate as either a redundant, SEU-tolerant, positive-logic, cross-coupled Nor Gate SR-flip flop or a redundant, SEU-tolerant, negative-logic, cross-coupled Nand Gate SR-flip flop. The register can operate as a memory, and further as a memory that can overcome the effects of radiation. As an SR-flip flop, the invention can be altered into any known type of latch or flip-flop by the application of external logic, thereby extending radiation tolerance to devices previously incapable of radiation tolerance. Numerous registers can be logically connected and replicated thereby being electronically configured to operate as a redundant circuit.

  12. Single event upset protection circuit and method

    DOEpatents

    Wallner, John; Gorder, Michael

    2016-03-22

    An SEU protection circuit comprises first and second storage means for receiving primary and redundant versions, respectively, of an n-bit wide data value that is to be corrected in case of an SEU occurrence; the correction circuit requires that the data value be a 1-hot encoded value. A parity engine performs a parity operation on the n bits of the primary data value. A multiplexer receives the primary and redundant data values and the parity engine output at respective inputs, and is arranged to pass the primary data value to an output when the parity engine output indicates `odd` parity, and to pass the redundant data value to the output when the parity engine output indicates `even` parity. The primary and redundant data values are suitably state variables, and the parity engine is preferably an n-bit wide XOR or XNOR gate.

  13. Method of making silicon on insalator material using oxygen implantation

    DOEpatents

    Hite, Larry R.; Houston, Ted; Matloubian, Mishel

    1989-01-01

    The described embodiments of the present invention provide a semiconductor on insulator structure providing a semiconductor layer less susceptible to single event upset errors (SEU) due to radiation. The semiconductor layer is formed by implanting ions which form an insulating layer beneath the surface of a crystalline semiconductor substrate. The remaining crystalline semiconductor layer above the insulating layer provides nucleation sites for forming a crystalline semiconductor layer above the insulating layer. The damage caused by implantation of the ions for forming an insulating layer is left unannealed before formation of the semiconductor layer by epitaxial growth. The epitaxial layer, thus formed, provides superior characteristics for prevention of SEU errors, in that the carrier lifetime within the epitaxial layer, thus formed, is less than the carrier lifetime in epitaxial layers formed on annealed material while providing adequate semiconductor characteristics.

  14. Modeling and assessing the influence of linear energy transfer on multiple bit upset susceptibility

    NASA Astrophysics Data System (ADS)

    Geng, Chao; Liu, Jie; Xi, Kai; Zhang, Zhan-Gang; Gu, Song; Liu, Tian-Qi

    2013-10-01

    The influence of the metric of linear energy transfer (LET) on single event upset (SEU), particularly multiple bit upset (MBU) in a hypothetical 90-nm static random access memory (SRAM) is explored. To explain the odd point of higher LET incident ion but induced lower cross section in the curve of SEU cross section, MBUs induced by incident ions 132Xe and 209Bi with the same LET but different energies at oblique incidence are investigated using multi-functional package for single event effect analysis (MUFPSA). In addition, a comprehensive analytical model of the radial track structure is incorporated into MUFPSA, which is a complementation for assessing and interpreting MBU susceptibility of SRAM. The results show that (i) with the increase of incident angle, MBU multiplicity and probability each present an increasing trend; (ii) due to the higher ion relative velocity and longer range of δ electrons, higher energy ions trigger the MBU with less probability than lower energy ions.

  15. On-orbit flight results from the reconfigurable cibola flight experiment satellite (CFEsat)

    SciTech Connect

    Caffrey, Michael; Morgan, Keith; Roussel-dupre, Diane; Robinson, Scott; Nelson, Anthony; Salazar, Anthony; Wirthlin, Michael; Howes, William; Richins, Daniel

    2009-01-01

    The Cibola Flight Experiment (CFE) is an experimental small satellite developed at the Los Alamos National Laboratory to demonstrate the feasibility of using FPGA-based reconfigurable computing for sensor processing in a space environment. The CFE satellite was launched on March 8, 2007 in low-earth orbit and has operated extremely well since its deployment. The nine Xilinx Virtex FPGAs used in the payload have been used for several high-throughput sensor processing applications and for single-event upset (SEU) monitoring and mitigation. This paper will describe the CFE system and summarize its operational results. In addition, this paper will describe the results from several SEU detection circuits that were performed on the spacecraft.

  16. Electronics Shielding and Reliability Design Tools

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; ONeill, P. M.; Zang, Thomas A., Jr.; Pandolf, John E.; Koontz, Steven L.; Boeder, P.; Reddell, B.; Pankop, C.

    2006-01-01

    It is well known that electronics placement in large-scale human-rated systems provides opportunity to optimize electronics shielding through materials choice and geometric arrangement. For example, several hundred single event upsets (SEUs) occur within the Shuttle avionic computers during a typical mission. An order of magnitude larger SEU rate would occur without careful placement in the Shuttle design. These results used basic physics models (linear energy transfer (LET), track structure, Auger recombination) combined with limited SEU cross section measurements allowing accurate evaluation of target fragment contributions to Shuttle avionics memory upsets. Electronics shielding design on human-rated systems provides opportunity to minimize radiation impact on critical and non-critical electronic systems. Implementation of shielding design tools requires adequate methods for evaluation of design layouts, guiding qualification testing, and an adequate follow-up on final design evaluation including results from a systems/device testing program tailored to meet design requirements.

  17. Silicon-on-sapphire fiber optic transceiver technology for space applications

    NASA Astrophysics Data System (ADS)

    Kuznia, C. P.; Ahadian, J. F.; Pommer, R. J.; Hagan, R.

    2007-09-01

    We present Single Event Upset (SEU) testing of a parallel fiber optic transceiver designed for communicating data using commercial Fibre Channel and GbE protocols at data rates up to 2.5 Gbps per channel (on eight parallel channels). This transceiver was developed for aircraft applications, such as the Joint Strike Fighter (JSF), Raptor and F/A-18 aircraft, that deploy fiber optic networks using multi-mode fiber operating at 850 nm wavelength. However, this transceiver may also have applications in space environments. This paper describes the underlying transceiver component technology, which utilizes complementary metal-oxide semiconductor (CMOS) silicon-onsapphire circuitry and GaAs VCSEL and PIN devices. We also present results of SEU testing of this transceiver using heavy ions at Brookhaven National Labs.

  18. NASA Education Forum at SAO on the Structure and Evolution of the Universe

    NASA Technical Reports Server (NTRS)

    Gould, Roy (Principal Investigator)

    2004-01-01

    Overview. The past year for the new SEU Forum has been a highly productive one and has moved us forward on three major objectives: Involving the public in the major scientific discoveries in our SEU theme this past year, especially the exciting discoveries about dark energy, cosmology, and black holes. Implementing the recommendations of the Knappenberger Report in order to strengthen the educational coherence of our collective activities. Developing strategic partnerships with underserved communities and other key customers . Among our activities for the past year are the following: Serving the Informal Science Education Communities: Summary of Goals, Plans and Activities for the Year 9/15/04 - 9/14/05. Interactions with the Space Science Community.

  19. Evaluation of an Ultra-Low Power Reed Solomon Encoder for NASA's Space Technology 5 Mission

    NASA Technical Reports Server (NTRS)

    Lei, K. E.; Xapsos, M. A.; Poivey, C.; LaBel, K. A.; Stone, R. F.; Yeh, P-S.; Gambles, J.; Hass, J.; Maki, G.; Murguia, J.

    2003-01-01

    Radiation test results and analyses are presented for ultra-low power Reed Solomon encoder circuits that are being considered for use on the Space Technology 5 (ST5) mission. The total ionizing dose tolerance is in excess of 100 krad(Si) and is due to the low supply voltage and the use of back-bias, which suppresses radiation-induced leakage currents in the n-channel devices. The circuits do not latch-up for ion LET values of at least 90 MeV-sq cm/mg. A hardened-by-design approach to SEU has achieved an upset threshold of about 20 MeV-sq cm/mg. The SEU rate expected for these circuits in the geosynchronous transfer orbit of ST5 is low.

  20. Transient SEUs in a fiber optic system for space applications

    NASA Technical Reports Server (NTRS)

    Label, Ken; Stassinopoulos, E. G.; Brucker, G. J.

    1991-01-01

    The results of an investigation on the SEU sensitivity for a fiber optic operating system are reported. Measurements were made on the upset cross sections for the system in static and dynamic modes of operation. The heavy ion SEU test facility at Brookhaven and the proton facility at Harvard University were used in this study. Cross sections were obtained for Honeywell transmitter and reciever devices operating in a system at a frequency of 100 kHz. Both devices were independently irradiated. The results show that the dynamic mode was the worst case, and the receiver was the most sensitive part type in the system. The threshold linear energy transfer (LET) for the receiver was determined to be 1.6 MeV sq cm/mg for the three input signals used in the tests, which were: a continuous high state, a low state, and a 100 kHz square wave.

  1. Total Dose Effects on Single Event Transients in Digital CMOS and Linear Bipolar Circuits

    NASA Technical Reports Server (NTRS)

    Buchner, S.; McMorrow, D.; Sibley, M.; Eaton, P.; Mavis, D.; Dusseau, L.; Roche, N. J-H.; Bernard, M.

    2009-01-01

    This presentation discusses the effects of ionizing radiation on single event transients (SETs) in circuits. The exposure of integrated circuits to ionizing radiation changes electrical parameters. The total ionizing dose effect is observed in both complementary metal-oxide-semiconductor (CMOS) and bipolar circuits. In bipolar circuits, transistors exhibit grain degradation, while in CMOS circuits, transistors exhibit threshold voltage shifts. Changes in electrical parameters can cause changes in single event upset(SEU)/SET rates. Depending on the effect, the rates may increase or decrease. Therefore, measures taken for SEU/SET mitigation might work at the beginning of a mission but not at the end following TID exposure. The effect of TID on SET rates should be considered if SETs cannot be tolerated.

  2. Computing in the presence of soft bit errors. [caused by single event upset on spacecraft

    NASA Technical Reports Server (NTRS)

    Rasmussen, R. D.

    1984-01-01

    It is shown that single-event-upsets (SEUs) due to cosmic rays are a significant source of single bit error in spacecraft computers. The physical mechanism of SEU, electron hole generation by means of Linear Energy Transfer (LET), it discussed with reference made to the results of a study of the environmental effects on computer systems of the Galileo spacecraft. Techniques for making software more tolerant of cosmic ray effects are considered, including: reducing the number of registers used by the software; continuity testing of variables; redundant execution of major procedures for error detection; and encoding state variables to detect single-bit changes. Attention is also given to design modifications which may reduce the cosmic ray exposure of on-board hardware. These modifications include: shielding components operating in LEO; removing low-power Schottky parts; and the use of CMOS diodes. The SEU parameters of different electronic components are listed in a table.

  3. The Galileo single-event upset solution and risk assessment

    NASA Technical Reports Server (NTRS)

    Burdick, Garry M.; Kopf, Edward H.; Meyer, Donald D.

    1986-01-01

    The Galileo probe will be subject to radiation fields and energetic particle bombardment during its outward bound journey and in orbit around Jupiter and its moons. To avoid the occurrence and propagation of effects of single event upset (SEU) bit state changes induced by the bombardments attempts were made to harden the Galileo electronics against SEUs. The hazards are especially acute for Schottky diode and low-power Schottky TTL parts. The preventive action options which were scheduled are reviewed, noting the selection of CMOS chips as replacements for SEU-susceptible devices. The simulation and risk assessment that were performed to evaluate the potential success of the replacements are summarized, with emphasis on the data employed to ensure the accuracy of the assessments and the predicted effects of SEUs in the various Galileo subsystems.

  4. 1986 Annual Conference on Nuclear and Space Radiation Effects, 23rd, Providence, RI, July 21-23, 1986, Proceedings

    NASA Technical Reports Server (NTRS)

    Ellis, Thomas D. (Editor)

    1986-01-01

    The present conference on the effects of nuclear and space radiation on electronic hardware gives attention to topics in the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, electronic device radiation hardness assurance, SOI/SOS radiation effects, spacecraft charging and space radiation, IC radiation effects and hardening, single-event upset (SEU) phenomena and hardening, and EMP/SGEMP/IEMP phenomena. Specific treatments encompass the generation of interface states by ionizing radiation in very thin MOS oxides, the microdosimetry of meson energy deposited on 1-micron sites in Si, total dose radiation and engineering studies, plasma interactions with biased concentrator solar cells, the transient imprint memory effect in MOS memories, mechanisms leading to SEU, and the vaporization and breakdown of thin columns of water.

  5. Single event induced transients in I/O devices - A characterization

    NASA Technical Reports Server (NTRS)

    Newberry, D. M.; Kaye, D. H.; Soli, G. A.

    1990-01-01

    The results of single-event upset (SEU) testing performed to evaluate the parametric transients, i.e., amplitude and duration, in several I/O devices, and the impact of these transients are discussed. The failure rate of these devices is dependent on the susceptibility of interconnected devices to the resulting transient change in the output of the I/O device. This failure rate, which is a function of the susceptibility of the interconnected device as well as the SEU response of the I/O device itself, may be significantly different from an upset rate calculated without taking these factors into account. The impact at the system level is discussed by way of an example.

  6. Laser-induced fluorescence of phosphors for remote cryogenic thermometry

    NASA Technical Reports Server (NTRS)

    Beshears, D. L.; Capps, G. J.; Cates, M. R.; Simmons, C. M.; Schwenterly, S. W.

    1990-01-01

    Remote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K.

  7. Single-Event Upset Characterization of Common First- and Second-Order All-Digital Phase-Locked Loops

    NASA Astrophysics Data System (ADS)

    Chen, Y. P.; Massengill, L. W.; Kauppila, J. S.; Bhuva, B. L.; Holman, W. T.; Loveless, T. D.

    2017-08-01

    The single-event upset (SEU) vulnerability of common first- and second-order all-digital-phase-locked loops (ADPLLs) is investigated through field-programmable gate array-based fault injection experiments. SEUs in the highest order pole of the loop filter and fraction-based phase detectors (PDs) may result in the worst case error response, i.e., limit cycle errors, often requiring system restart. SEUs in integer-based linear PDs may result in loss-of-lock errors, while SEUs in bang-bang PDs only result in temporary-frequency errors. ADPLLs with the same frequency tuning range but fewer bits in the control word exhibit better overall SEU performance.

  8. A comparison of heavy ion induced single event upset susceptibility in unhardened 6T/SRAM and hardened ADE/SRAM

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Zeng, Chuanbin; Geng, Chao; Liu, Tianqi; Khan, Maaz; Yan, Weiwei; Hou, Mingdong; Ye, Bing; Sun, Youmei; Yin, Yanan; Luo, Jie; Ji, Qinggang; Zhao, Fazhan; Liu, Jie

    2017-09-01

    Single event upset (SEU) susceptibility of unhardened 6T/SRAM and hardened active delay element (ADE)/SRAM, fabricated with 0.35 μm silicon-on-insulator (SOI) CMOS technology, was investigated at heavy ion accelerator. The mechanisms were revealed by the laser irradiation and resistor-capacitor hardened techniques. Compared with conventional 6T/SRAM, the hardened ADE/SRAM exhibited higher tolerance to heavy ion irradiation, with an increase of about 80% in the LET threshold and a decrease of ∼64% in the limiting upset cross-section. Moreover, different probabilities between 0 → 1 and 1 → 0 transitions were observed, which were attributed to the specific architecture of ADE/SRAM memory cell. Consequently, the radiation-hardened technology can be an attractive alternative to the SEU tolerance of the device-level.

  9. NASA Structure and Evolution of the Universe Theme: Science Overview

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Margon, Bruce

    2001-01-01

    The NASA Office of Space Science Structure and Evolution of the Universe (SEU) theme covers a wide variety of scientific investigations, from the nearest bodies to the farthest observable distances just after the time of the Big Bang. SEU supports experiments that sense radiation of all wavelengths, together with particle and gravitational wave detection. Recently completed road mapping and strategic planning exercises have identified a number of near- and medium-term space initiatives for the 2003-2023 time frame. Each of these experiments pushes the state of the art technically, but will return incredible new insights on the formation and evolution of the universe, as well as probe fundamental laws of physics in regimes never before tested. The scientific goals and technological highlights of each mission are described.

  10. SEE Sensitivity Analysis of 180 nm NAND CMOS Logic Cell for Space Applications

    NASA Astrophysics Data System (ADS)

    Sajid, Muhammad

    2016-07-01

    This paper focus on Single Event Effects caused by energetic particle strike on sensitive locations in CMOS NAND logic cell designed in 180nm technology node to be operated in space radiation environment. The generation of SE transients as well as upsets as function of LET of incident particle has been determined for logic devices onboard LEO and GEO satellites. The minimum magnitude pulse and pulse-width for threshold LET was determined to estimate the vulnerability /susceptibility of device for heavy ion strike. The impact of temperature, strike location and logic state of NAND circuit on total SEU/SET rate was estimated with physical mechanism simulations using Visual TCAD, Genius, runSEU program and Crad computer codes.

  11. Laser-induced fluorescence of phosphors for remote cryogenic thermometry

    NASA Technical Reports Server (NTRS)

    Beshears, D. L.; Capps, G. J.; Cates, M. R.; Simmons, C. M.; Schwenterly, S. W.

    1990-01-01

    Remote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K.

  12. 1986 Annual Conference on Nuclear and Space Radiation Effects, 23rd, Providence, RI, July 21-23, 1986, Proceedings

    NASA Technical Reports Server (NTRS)

    Ellis, Thomas D. (Editor)

    1986-01-01

    The present conference on the effects of nuclear and space radiation on electronic hardware gives attention to topics in the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, electronic device radiation hardness assurance, SOI/SOS radiation effects, spacecraft charging and space radiation, IC radiation effects and hardening, single-event upset (SEU) phenomena and hardening, and EMP/SGEMP/IEMP phenomena. Specific treatments encompass the generation of interface states by ionizing radiation in very thin MOS oxides, the microdosimetry of meson energy deposited on 1-micron sites in Si, total dose radiation and engineering studies, plasma interactions with biased concentrator solar cells, the transient imprint memory effect in MOS memories, mechanisms leading to SEU, and the vaporization and breakdown of thin columns of water.

  13. Laser-induced fluorescence of phosphors for remote cryogenic thermometry

    NASA Astrophysics Data System (ADS)

    Beshears, D. L.; Capps, G. J.; Cates, M. R.; Simmons, C. M.; Schwenterly, S. W.

    1990-10-01

    Remote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K.

  14. Laser-induced fluorescence of phosphors for remote cryogenic thermometry

    NASA Astrophysics Data System (ADS)

    Beshears, D. L.; Capps, G. J.; Cates, M. R.; Simmons, C. M.; Schwenterly, S. W.

    1990-12-01

    Remote cryogenic temperature measurements can be made by inducing fluorescence in phosphors with temperature-dependent emissions and measuring the emission lifetimes. The thermographic phosphor technique can be used for making precision, noncontact, cryogenic-temperature measurements in electrically hostile environments, such as high dc electric or magnetic fields. The National Aeronautics and Space Administration is interested in using these thermographic phosphors for mapping hot spots on cryogenic tank walls. Europium-doped lanthanum oxysulfide (La2O2S:Eu) and magnesium fluorogermanate doped with manganese (Mg4FGeO6:Mn) are suitable for low-temperature surface thermometry. Several emission lines, excited by a 337-nm ultraviolet laser, provide fluorescence lifetimes having logarithmic dependence with temperature from 4 to above 125 K. A calibration curve for both La2O2S:Eu and Mg4FGeO6:Mn is presented, as well as emission spectra taken at room temperature and 11 K.

  15. Heavy Ion Irradiation Fluence Dependence for Single-Event Upsets in a NAND Flash Memory

    NASA Technical Reports Server (NTRS)

    Chen, Dakai; Wilcox, Edward; Ladbury, Raymond L.; Kim, Hak; Phan, Anthony; Seidleck, Christina; Label, Kenneth

    2016-01-01

    We investigated the single-event effect (SEE) susceptibility of the Micron 16 nm NAND flash, and found that the single-event upset (SEU) cross section varied inversely with cumulative fluence. We attribute the effect to the variable upset sensitivities of the memory cells. Furthermore, the effect impacts only single cell upsets in general. The rate of multiple-bit upsets remained relatively constant with fluence. The current test standards and procedures assume that SEU follow a Poisson process and do not take into account the variability in the error rate with fluence. Therefore, traditional SEE testing techniques may underestimate the on-orbit event rate for a device with variable upset sensitivity.

  16. Heavy ion microscopy of single event upsets in CMOS SRAMs

    SciTech Connect

    Metzger, S.; Dreute, J.; Heinrich, W.; Roecher, H. ); Fischer, B.E. ); Harboe-Soerensen, R.; Adams, L. )

    1994-06-01

    The single event upset (SEU) imaging has been applied at the GSI heavy ion microprobe to determine the sensitivity of integrated circuits (IC) to heavy ion irradiation. This method offers the possibility to directly image those parts of an IC which are sensitive to ion-induced malfunctions. By a 3-dimensional simulation of charge collection across p-n-micro-junctions the authors can predict SEU cross-sections. For a MHS65162 2k [times] 8bit CMOS SRAM they found two regions per bit with different sensitivity and measured a total cross-section of (71[+-]18)[mu]m[sup 2] for a bitflip per cell and simulated 60[mu]m[sup 2] with an argon beam of 1.4 MeV/nucl. (LET of 19.7 MeV/mg/cm[sup 2]).

  17. The Cibola flight experiment

    SciTech Connect

    Caffrey, Michael Paul; Nelson, Anthony; Salazar, Anthony; Roussel - Dupre, Diane; Katko, Kim; Palmer, Joseph; Robinson, Scott; Wirthlin, Michael; Howes, William; Richins, Daniel

    2009-01-01

    The Cibola Flight Experiment (CFE) is an experimental small satellite carrying a reconfigurable processing instrument developed at the Los Alamos National Laboratory that demonstrates the feasibility of using FPGA-based high-performance computing for sensor processing in the space environment. The CFE satellite was launched on March 8, 2007 in low-earth orbit and has operated extremely well since its deployment. The nine Xilinx Virtex FPGAs used in the payload have been used for several high-throughput sensor processing applications and for single-event upset (SEU) monitoring and mitigation. This paper will describe the CFE system and summarize its operational results. In addition, this paper will describe the results from several SEU detection circuits that were performed on the spacecraft.

  18. Analysis of single-event upset of magnetic tunnel junction used in spintronic circuits caused by radiation-induced current

    SciTech Connect

    Sakimura, N.; Nebashi, R.; Sugibayashi, T.; Natsui, M.; Hanyu, T.; Ohno, H.

    2014-05-07

    This paper describes the possibility of a switching upset of a magnetic tunnel junction (MTJ) caused by a terrestrial radiation-induced single-event-upset (SEU) current in spintronic integrated circuits. The current waveforms were simulated by using a 3-D device simulator in a basic circuit including MTJs designed using 90-nm CMOS parameters and design rules. The waveforms have a 400 -μA peak and a 200-ps elapsed time when neutron particles with a linear energy transfer value of 14 MeV cm{sup 2}/mg enter the silicon surface. The authors also found that the SEU current may cause soft errors with a probability of more than 10{sup −12} per event, which was obtained by approximate solution of the ordinary differential equation of switching probability when the intrinsic critical current (I{sub C0}) became less than 30 μA.

  19. Gadolinium oxysulfide nanoparticles as multimodal imaging agents for T2-weighted MR, X-ray tomography and photoluminescence

    NASA Astrophysics Data System (ADS)

    Osseni, Sèmiyou. A.; Lechevallier, Sévérine; Verelst, Marc; Perriat, Pascal; Dexpert-Ghys, Jeannette; Neumeyer, David; Garcia, Robin; Mayer, Florian; Djanashvili, Kristina; Peters, Joop A.; Magdeleine, Eddy; Gros-Dagnac, Hélène; Celsis, Pierre; Mauricot, Robert

    2013-12-01

    We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under excitation in the NUV (365 nm). They are not cytotoxic for living cells up to 100 μg mL-1. Consequently, they are well adapted for in vitro imaging on cell cultures. Gd2O2S:Eu3+ NPs also show strong transverse relaxivity and strong X-ray absorption allowing their use as contrast agents for T2-weighted MRI and X-ray tomography. Our study shows that Gd2O2S:Eu3+ NPs are considerably better than commercial Ferumoxtran-10 NPs as negative contrast agents for MRI. Upconversion emission of Gd2O2S:Er; Yb (1; 8%) NPs under infrared excitation (λex = 980 nm) shows mainly red emission (~650-680 nm). Consequently, they are more specifically designed for in vivo deep fluorescence imaging, because both excitation and emission are located inside the ``transparency window'' of biological tissues (650-1200 nm). Magnetic relaxivity and X-ray absorption behaviors of Gd2O2S:Er; Yb NPs are almost similar to Gd2O2S:Eu3+ NPs.We have synthesized gadolinium oxysulfide nanoparticles (NPs) doped with other lanthanides (Eu3+, Er3+, Yb3+) via a hydroxycarbonate precursor precipitation route followed by a sulfuration process under a H2S-Ar atmosphere at 750 °C in order to propose new multimodal nanoplatforms for Magnetic Resonance (MR), X-ray and photoluminescence imaging. Gd2O2S:Eu3+ NPs strongly absorb near UV (~300-400 nm) and re-emit strong red light (624 nm). They can be easily internalized by cancer cells, and imaged by epifluorescence microscopy under

  20. Characterizing SRAM Single Event Upset in Terms of Single and Double Node Charge Collection

    NASA Technical Reports Server (NTRS)

    Black, J. D.; Ball, D. R., II; Robinson, W. H.; Fleetwood, D. M.; Schrimpf, R. D.; Reed, R. A.; Black, D. A.; Warren, K. M.; Tipton, A. D.; Dodd, P. E.; hide

    2008-01-01

    A well-collapse source-injection mode for SRAM SEU is demonstrated through TCAD modeling. The recovery of the SRAM s state is shown to be based upon the resistive path from the p+-sources in the SRAM to the well. Multiple cell upset patterns for direct charge collection and the well-collapse source-injection mechanisms are then predicted and compared to recent SRAM test data.

  1. Traycans: Tinplate vs. Tin-Free Steel. Phase 1

    DTIC Science & Technology

    1991-05-01

    AD-A236 686 TECHNICAL REPORT NATICK/ TR-91 / 030 AD TRAYCANS: TINPLATE VS TIN-FREE STEEL PHASE I By Jeanne M. Ross DTICELECTE May 1991 NO5 SEU B D...inspected both internally and externally for aberrations after predetermined periods of storage. Test results slxwed that tinplate did proivide improved...extended by converting the current traycan from tin-free steel to tinplated steel. To acoamplish this, an optimal traycan had to be developed composed of

  2. Radiation Test Results for Common CubeSat Microcontrollers and Microprocessors

    NASA Technical Reports Server (NTRS)

    Guertin, Steven M.; Amrbar, Mehran; Vartanian, Sergeh

    2015-01-01

    SEL, SEU, and TID results are presented for microcontrollers and microprocessors of interest for small satellite systems such as the TI MSP430F1611, MSP430F1612 and MSP430FR5739, Microchip PIC24F256GA110 and dsPIC33FJ256GP710, Atmel AT91SAM9G20, and Intel Atom E620T, and the Qualcomm Snapdragon APQ8064.

  3. An Analysis of the Effects of Tectonic Release on Short-Period P Waves Observed from Shagan River Explosions.

    DTIC Science & Technology

    1987-02-01

    Pattern am ionw/,,, Seismology IL Auebsfqt Ualofe. it. o""" CMaas (The Samel 21. Ifta. o w Page Release Unlimited UNCLASSIFIED 63 2 -Seu mce (Thee Bagel...0.1 10 20 30 40 50 60 70 80 90 Azimuth, degrees 0.5 _ Explosion + Tectonic, F = 1.3 0.4 . 0.3 AM b 0.2 0.1 - 10 20 30 40 50 60 70 80 90 Azimuth

  4. Calculations of the Interactions of Energetic Ions with Materials for Protection of Computer Memory and Biological Systems

    NASA Astrophysics Data System (ADS)

    Kim, Myung-Hee Yoon

    1995-01-01

    Theoretical calculations were performed for the propagation and interactions of particles having high atomic numbers and energy through diverse shield materials including polymeric materials and epoxy-bound lunar regolith by using transport codes for laboratory ion beams and the cosmic ray spectrum. Heavy ions fragment and lose energy upon interactions with shielding materials of specified elemental composition, density, and thickness. A fragmenting heavy iron ion produces hundreds of isotopes during nuclear reactions, which are treated in the solution of the transport problem used here. A reduced set of 80 isotopes is sufficient to represent the charge distribution, but a minimum of 122 isotopes is necessary for the mass distribution. These isotopes are adequate for ion beams with charges equal to or less than 26. To predict the single event upset (SEU) rate in electronic devices, the resultant linear energy transfer (LET) spectra from the transport code behind various materials are coupled with a measured SEU cross section versus LET curve. The SEU rate on static random access memory (SRAM) is shown as a function of shield thickness for various materials. For a given mass the most effective shields for SEU reduction are materials with high hydrogen density, such as polyethylene. The shield effectiveness for protection of biological systems is examined by using conventional quality factors to calculate the dose equivalents and also by using the probability of the neoplastic transformation of shielded C3H10T1/2 mouse cells. The attenuation of biological effects within the shield and body tissues depends on the materials properties. The results predict that hydrogenous materials are good candidates for high-performance shields. Two biological models were used. Quantitative results depended upon model.

  5. In-flight and ground testing of single event upset sensitivity in static RAMs

    SciTech Connect

    Johansson, K.; Dyreklev, P.; Granbom, B.; Calvet, C.; Fourtine, S.; Feuillatre, O.

    1998-06-01

    This paper presents the results from in-flight measurements of single event upsets (SEU) in static random access memories (SRAM) caused by the atmospheric radiation environment at aircraft altitudes. The memory devices were carried on commercial airlines at high altitude and mainly high latitudes. The SEUs were monitored by a Component Upset Test Equipment (CUTE), designed for this experiment. The in flight results are compared to ground based testing with neutrons from three different sources.

  6. Antifuse FPGA for Space Applications

    NASA Technical Reports Server (NTRS)

    Wang, Jih-Jong; Cronquist, Brian E.; Sin, Benny; Moriarta, Jennifer J.; Katz, Richard B.

    1997-01-01

    This paper presents total dose and SEE testing data of recent antifuse products. It includes ONO-antifuse FPGAS: A1020B, A1020S, RH1020, A1280XL, A1460A, A14100A, A32140DX and A32200DX. Also included are preliminary results of pre-production metal to metal (M/M) antifuse FPGAs, the I100 and the RHI100. Finally, SEU rate calculations of Actel FPGAs are discussed.

  7. The Interagency Breakdown: Why We Need Legislative Reform to Coordinate Execution of the National Security Strategy

    DTIC Science & Technology

    2008-04-01

    core areas that the reform needs to address require analysis . The analysis starts with the fact that the National Security Strategy is the centerpiece... tinder 5om!1iI𔃻 .t>:l A:s1stanl seu.Ia’~ CltIP. /JirFtlrce Marine Corps Major Commands & Agencies Cl:iH or N>\\𔃻J1 Opemlions Navy Major Commands &A

  8. Fault-Tolerant Coding for State Machines

    NASA Technical Reports Server (NTRS)

    Naegle, Stephanie Taft; Burke, Gary; Newell, Michael

    2008-01-01

    Two reliable fault-tolerant coding schemes have been proposed for state machines that are used in field-programmable gate arrays and application-specific integrated circuits to implement sequential logic functions. The schemes apply to strings of bits in state registers, which are typically implemented in practice as assemblies of flip-flop circuits. If a single-event upset (SEU, a radiation-induced change in the bit in one flip-flop) occurs in a state register, the state machine that contains the register could go into an erroneous state or could hang, by which is meant that the machine could remain in undefined states indefinitely. The proposed fault-tolerant coding schemes are intended to prevent the state machine from going into an erroneous or hang state when an SEU occurs. To ensure reliability of the state machine, the coding scheme for bits in the state register must satisfy the following criteria: 1. All possible states are defined. 2. An SEU brings the state machine to a known state. 3. There is no possibility of a hang state. 4. No false state is entered. 5. An SEU exerts no effect on the state machine. Fault-tolerant coding schemes that have been commonly used include binary encoding and "one-hot" encoding. Binary encoding is the simplest state machine encoding and satisfies criteria 1 through 3 if all possible states are defined. Binary encoding is a binary count of the state machine number in sequence; the table represents an eight-state example. In one-hot encoding, N bits are used to represent N states: All except one of the bits in a string are 0, and the position of the 1 in the string represents the state. With proper circuit design, one-hot encoding can satisfy criteria 1 through 4. Unfortunately, the requirement to use N bits to represent N states makes one-hot coding inefficient.

  9. Implementation of a Configurable Fault Tolerant Processor (CFTP)

    DTIC Science & Technology

    2003-03-01

    Programmable Gate Array ( FPGA ), Single Event Upset (SEU), 16-Bit RISC 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...A: CFTP SCHEMATICS AND CODE Appendix A contains all the schematics and VHDL code files that were specific- ally built for this thesis. It does not...associated KDLX files, as well as the state machine design from which the Interrup VHDL code was derived. The VHDL files for the KDLX processor were not

  10. Single-Event Upset and Scaling Trends in New Generation of the Commercial SOI PowerPC Microprocessors

    NASA Technical Reports Server (NTRS)

    Irom, Farokh; Farmanesh, Farhad; Kouba, Coy K.

    2006-01-01

    SEU from heavy-ions is measured for SOI PowerPC microprocessors. Results for 0.13 micron PowerPC with 1.1V core voltages increases over 1.3V versions. This suggests that improvement in SEU for scaled devices may be reversed. In recent years there has been interest in the possible use of unhardened commercial microprocessors in space because of their superior performance compared to hardened processors. However, unhardened devices are susceptible to upset from radiation space. More information is needed on how they respond to radiation before they can be used in space. Only a limited number of advanced microprocessors have been subjected to radiation tests, which are designed with lower clock frequencies and higher internal core voltage voltages than recent devices [1-6]. However the trend for commercial Silicon-on-insulator (SOI) microprocessors is to reduce feature size and internal core voltage and increase the clock frequency. Commercial microprocessors with the PowerPC architecture are now available that use partially depleted SOI processes with feature size of 90 nm and internal core voltage as low as 1.0 V and clock frequency in the GHz range. Previously, we reported SEU measurements for SOI commercial PowerPCs with feature size of 0.18 and 0.13 m [7, 8]. The results showed an order of magnitude reduction in saturated cross section compared to CMOS bulk counterparts. This paper examines SEUs in advanced commercial SOI microprocessors, focusing on SEU sensitivity of D-Cache and hangs with feature size and internal core voltage. Results are presented for the Motorola SOI processor with feature sizes of 0.13 microns and internal core voltages of 1.3 and 1.1 V. These results are compared with results for the Motorola SOI processors with feature size of 0.18 microns and internal core voltage of 1.6 and 1.3 V.

  11. Radiation Tests on 2Gb NAND Flash Memories

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc N.; Guertin, Steven M.; Patterson, J. D.

    2006-01-01

    We report on SEE and TID tests of highly scaled Samsung 2Gbits flash memories. Both in-situ and biased interval irradiations were used to characterize the response of the total accumulated dose failures. The radiation-induced failures can be categorized as followings: single event upset (SEU) read errors in biased and unbiased modes, write errors, and single-event-functional-interrupt (SEFI) failures.

  12. USAF Credits for the Destruction of Enemy Aircraft, World War II

    DTIC Science & Technology

    1978-01-01

    duty a Year• . tColonel Benjamin B. Williams, USAFR, joined the project in 1967, and has monitored the work of the other reservists who have been in...7 THIS PAGE Declassified lAW E012958 This Page Declassified lAW E012958 ~ANK SE~U~ NR ~eRVICF unIT T"’EATE~ (~E~n DArr fir: l:RFIHf (JlEW flAY 1,10

  13. Space Weather Effects on Range Operations

    DTIC Science & Technology

    2013-02-01

    monitor the accumulated dose via the measured threshold voltage shift. Example measurements from the CREDO monitor flown on APEX (352x2486 km, 70o...CREAM (Cosmic Radiation Effects and Activation Monitor) and CREDO (Cosmic Radiation Effects and Dosimetry) detectors are designed to monitor those aspects...CREAM and CREDO -I instruments the SEU environment is monitored by means of pulse-height analysis of the charge-deposition spectra in ten pin diodes

  14. Radiation Tests on 2Gb NAND Flash Memories

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc N.; Guertin, Steven M.; Patterson, J. D.

    2006-01-01

    We report on SEE and TID tests of highly scaled Samsung 2Gbits flash memories. Both in-situ and biased interval irradiations were used to characterize the response of the total accumulated dose failures. The radiation-induced failures can be categorized as followings: single event upset (SEU) read errors in biased and unbiased modes, write errors, and single-event-functional-interrupt (SEFI) failures.

  15. Single Event Upset Sensitivity of D-Flip Flop: Comparison of PDSOI With Bulk Si at 130 nm Technology Node

    NASA Astrophysics Data System (ADS)

    Zhang, Leqing; Xu, Jialing; Fan, Shuang; Dai, Lihua; Bi, Dawei; Lu, Jian; Hu, Zhiyuan; Zhang, Mengying; Zhang, Zhengxuan

    2017-01-01

    Single-event upsets are studied in digital storage cells in 130nm CMOS bulk Si and PDSOI technologies. The sensitivity of SEU to different technologies and hardening approaches is explored by using heavy-ion radiation experiments. Error numbers in D flip-flop chains are used to determine the impact of various cell designs and PDSOI hardening technique on upset sensitivity. Various flip-flops are designed and connected as shift-register chains, and the error numbers induced by irradiation are recorded to examine the effectiveness of the PDSOI technology. It was found that PDSOI technology has better performance in terms of upset robustness versus bulk Si at the 130nm technology node. The same design structure implemented in PDSOI technology has higher SEU threshold LET and much lower saturation cross section due to its full dielectric isolation structure which does not allow the charge generated in the substrate to be collected by the electrically active junctions in the thin top region of the device and reduces the sensitive volume of p-n junctions in the transistor. As shown in the experiment result, NRH_SOI (not radiation hardening SOI) saves about 25% area while having much lower SER versus DICE_Si, which means PDSOI still has obvious advantage at reducing SEU rate, even though its necessary body contact has to consume certain extra area.

  16. Apparatus for and method of eliminating single event upsets in combinational logic

    NASA Technical Reports Server (NTRS)

    Gambles, Jody W. (Inventor); Hass, Kenneth J. (Inventor); Cameron, Kelly B. (Inventor)

    2001-01-01

    An apparatus for and method of eliminating single event upsets (or SEU) in combinational logic are used to prevent error propagation as a result of cosmic particle strikes to the combinational logic. The apparatus preferably includes a combinational logic block electrically coupled to a delay element, a latch and an output buffer. In operation, a signal from the combinational logic is electrically coupled to a first input of the latch. In addition, the signal is routed through the delay element to produce a delayed signal. The delayed signal is routed to a second input of the latch. The latch used in the apparatus for preventing SEU preferably includes latch outputs and a feature that the latch outputs will not change state unless both latch inputs are correct. For example, the latch outputs may not change state unless both latch inputs have the same logical state. When a cosmic particle strikes the combinational logic, a transient disturbance with a predetermined length may appear in the signal. However, a function of the delay element is to preferably provide a time delay greater than the length of the transient disturbance. Therefore, the transient disturbance will not reach both latch inputs simultaneously. As a result, the latch outputs will not permanently change state in error due to the transient disturbance. In addition, the output buffer preferably combines the latch outputs in such a way that the correct state is preserved at all times. Thus, combinational logic with protection from SEU is provided.

  17. The physics of a single-event upset in integrated circuits: A review and critique of analytical models for charge collection

    NASA Technical Reports Server (NTRS)

    Vonroos, O.; Zoutendyk, J.

    1983-01-01

    When an energetic particle (kinetic energy 0.5 MeV) originating from a radioactive decay or a cosmic ray transverse the active regions of semiconductor devices used in integrated circuit (IC) chips, it leaves along its track a high density electron hole plasma. The subsequent decay of this plasma by drift and diffusion leads to charge collection at the electrodes large enough in most cases to engender a false reading, hence the name single-event upset (SEU). The problem of SEU's is particularly severe within the harsh environment of Jupiter's radiation belts and constitutes therefore a matter of concern for the Galileo mission. The physics of an SEU event is analyzed in some detail. Owing to the predominance of nonlinear space charge effects and the fact that positive (holes) and negative (electrons) charges must be treated on an equal footing, analytical models for the ionized-charge collection and their corresponding currents as a function of time prove to be inadequate even in the simplest case of uniformly doped, abrupt p-n junctions in a one-dimensional geometry. The necessity for full-fledged computer simulation of the pertinent equations governing the electron-hole plasma therefore becomes imperative.

  18. For ‘Physitians of the Soule’

    PubMed Central

    Firth-Godbehere, Richard

    2015-01-01

    This article attempts to understand how Thomas Wright’s 1604 work, The Passions of the Minde in Generall, might have fitted into his overall mission as an English Catholic preacher, particularly when read via Wright’s understanding of Thomas Aquinas’s passion of fuga seu abominatio. Some historians claim that Wright was a controversialist, previously describing The Passions as either a radical departure from Wright’s mission, or the work of a different Thomas Wright. Earlier attempts to find a missionary element within The Passions have been inadequate. Through a close reading of The Passions, specifically analysing Wright's interpretation of fuga seu abominatio within the context of Wright’s intended readership, the main message of The Passions, and his background, this article suggests a possible reading of the text as a work aimed specifically at fellow English Catholics. To Wright, the passions of hatred of abomination and flight or detestation, derived primarily from Aquinas’s fuga seu abominatio, were not simply a form of disgust, as often assumed, but the potential worldly or otherworldly harm that someone we love, such as a neighbour, might face from the abominable evil of sin and damnation. By linking hatred of abomination, flight or detestation, and Wright’s particular view of sin together, Wright was teaching English Catholics how these passions might be used to cure diseased souls, turning the work into a guide for preaching. PMID:26870634

  19. Seulimeum segment characteristic indicated by 2-D resistivity imaging method

    NASA Astrophysics Data System (ADS)

    Syukri, M.; Saad, R.

    2017-06-01

    The study conducted at Aceh (Indonesia) within Krueng Raya and Ie Seu Um vicinity with the same geology setting (Lam Teuba volcanic), to study Seulimeum Segment characteristic using 2-D resistivity imaging method. The 2-D resistivity survey applied Pole-dipole array with minimum electrode spacing of 2 and 5 m for Ie Seu Um study area, while 10 m for Krueng Raya area. Resistivity value of Ie Seu Um study area has been correlated and validated with existing outcrops and hot springs which the value used to identify overburden, saturated area and bedrock of Krueng Raya area. The resistivity value of overburden in Krueng Raya area was identify as <30 Ohm.m, bedrock is >30 Ohm.m and saturated zone is <9 Ohm.m. The imaging results used to identify the Seulimeum segment system, where the depth is increasing from southern part (20-50 m) to northern part (50-200 m) when approaching the Andaman Sea and breaks into two sections to produce horst and graben system which indicate that it produced from the moving plat.

  20. Solar and Galactic Cosmic Rays Observed by SOHO

    NASA Astrophysics Data System (ADS)

    Fleck, Bernhard; Curdt, Werner; Olive, Jean-Philippe; van Overbeek, Ton

    2015-04-01

    Both the Cosmic Ray Flux (CRF) and Solar Energetic Particles (SEPs) have left an imprint on SOHO technical systems. While the solar array efficiency degraded irreversibly down to 75% of its original level over 1 ½ solar cycles, Single Event Upsets (SEUs) in the solid state recorder (SSR) have been reversed by the memory protection mechanism. We compare the daily CRF observed by the Oulu station with the daily SOHO SEU rate and with the degradation curve of the solar arrays. The Oulu CRF and the SOHO SSR SEU rate are both modulated by the solar cycle and are highly correlated, except for sharp spikes in the SEU rate, caused by isolated SEP events, which also show up as discontinuities in the otherwise slowly decreasing solar ray efficiency. This allows to discriminate between effects with solar and non-solar origin and to compare the relative strength of both. We find that the total number of SSR SEUs with solar origin over the 17 ½ years from January 1996 through June 2013 is of the same order as those generated by cosmic ray hits. 49% of the total solar array degradation during that time can be attributed to proton events, i.e. the effect of a series of short-lived, violent events (SEPs) is comparable to the cycle-integrated damage by cosmic rays.

  1. The board implementation of AVR microcontroller checking for single event upsets

    NASA Astrophysics Data System (ADS)

    Lho, Young Hwan; Jang, Dae Jin; Seo, Kang Kuk; Jung, Jae Ho; Kim, Ki Yup

    2005-12-01

    Radiation hardening parts are to be used for satellites and nuclear power plants due to various kinds of radiation particles in space and radiation environment. Here, our focus is to implement a testing board of AVR Microcontroller checking for Single Event Upsets (SEU); the effects of protons on the electronic devices. The SEU results form the level change of stored information due to photon radiation and temperature in the space environment. The impact of SEU on PLD (Programmable Logic Devices) technology is most apparent in SRAM/ROM/DRAM devices wherein the state of storage cell can be upset. In this research, a simple and powerful test technique is suggested, and the results are presented for the analysis and future reference. In our experiment, the proton radiation facility (having the energy of 30 MeV with a beam current of 20 uA in the cyclotron) available at KIRAMS (Korea Institute of Radiological Medical Sciences) has been applied on two kinds of commercially available SRAM and EEPROM.

  2. Low Altitude Validation of Geomagnetic Cutoff Models Using SAMPEX Data

    NASA Astrophysics Data System (ADS)

    Young, S. L.; Kress, B. T.

    2011-12-01

    Single event upsets (SEUs) caused by MeV protons are a concern for satellite operators so AFRL is working to create a tool that can specify and/or forecast SEU probabilities. An important component of the tool's SEU probability calculation will be the local energetic ion spectrum. The portion of that spectrum due to trapped energetic ion population is relatively stable and predictable; however it is more difficult to account for the transient solar energetic particles (SEPs). These particles, which can be ejected from the solar atmosphere during a solar flare or filament eruption or can be energized by coronal mass ejection (CME) driven shocks, can penetrate the Earth's magnetosphere into regions not normally populated by energetic protons. The magnetosphere will provide energy dependent shielding that also depends on its magnetic configuration. During magnetic storms that configuration is modified and the SEP cutoff latitude for a given particle energy can be suppressed up to ~15 degrees equatorward exposing normally shielded regions. As a first step to creating the satellite SEU prediction tool, we are comparing the Smart et al. (Advances in Space Research, 2006) and CISM-Dartmouth (Kress et al., Space Weather, 2010) geomagnetic cutoff tools. While they have provided some of their own validations in the noted papers, our validation will be done consistently between models allowing us to better compare the models.

  3. Prediction of error rates in dose-imprinted memories on board CRRES by two different methods

    NASA Astrophysics Data System (ADS)

    Brucker, G. J.; Stassinopoulos, E. G.

    1991-06-01

    An analysis of the expected space radiation effects on the single event upset (SEU) properties of CMOS/bulk memories onboard the Combined Release and Radiation Effects Satellite (CRRES) is presented. Dose-imprint data from ground test irradiations of identical devices are applied to the predictions of cosmic-ray-induced space upset rates in the memories onboard the spacecraft. The calculations take into account the effect of total dose on the SEU sensitivity of the devices as the dose accumulates in orbit. Estimates of error rates, which involved an arbitrary selection of a single pair of threshold linear energy transfer (LET) and asymptotic cross-section values, were compared to the results of an integration over the cross-section curves versus LET. The integration gave lower upset rates than the use of the selected values of the SEU parameters. Since the integration approach is more accurate and eliminates the need for an arbitrary definition of threshold LET and asymptotic cross section, it is recommended for all error rate predictions where experimental sigma-versus-LET curves are available.

  4. Soft-error tolerance and energy consumption evaluation of embedded computer with magnetic random access memory in practical systems using computer simulations

    NASA Astrophysics Data System (ADS)

    Nebashi, Ryusuke; Sakimura, Noboru; Sugibayashi, Tadahiko

    2017-08-01

    We evaluated the soft-error tolerance and energy consumption of an embedded computer with magnetic random access memory (MRAM) using two computer simulators. One is a central processing unit (CPU) simulator of a typical embedded computer system. We simulated the radiation-induced single-event-upset (SEU) probability in a spin-transfer-torque MRAM cell and also the failure rate of a typical embedded computer due to its main memory SEU error. The other is a delay tolerant network (DTN) system simulator. It simulates the power dissipation of wireless sensor network nodes of the system using a revised CPU simulator and a network simulator. We demonstrated that the SEU effect on the embedded computer with 1 Gbit MRAM-based working memory is less than 1 failure in time (FIT). We also demonstrated that the energy consumption of the DTN sensor node with MRAM-based working memory can be reduced to 1/11. These results indicate that MRAM-based working memory enhances the disaster tolerance of embedded computers.

  5. A follow-up of in-orbit observations of radiation-induced effects in commercial of the shelf memories on-board Alsat-1

    NASA Astrophysics Data System (ADS)

    Bentoutou, Y.

    2011-09-01

    This paper presents a follow-up of the results of an 8-year study on radiation effects in commercial off the shelf (COTS) memory devices operating within the on-board data handling system of the Algerian micro-satellite Alsat-1 in a Low-Earth Orbit (LEO). A statistical analysis of single-event upset (SEU) and multiple-bit upset (MBU) activity in commercial memories on-board the Alsat-1 primary On-Board Computer (OBC-386) is given. The OBC-386 is an Intel 80C386EX based system that plays a dual role for Alsat-1, acting as the key component of the payload computer as well as the command and control computer for the micro-satellite. The in-orbit observations show that the typical SEU rate at Alsat-1's orbit is 4.04 × 10 -7 SEU/bit/day, where 98.6% of these SEUs cause single-bit errors, 1.22% cause double-byte errors, and the remaining SEUs result in multiple-bit and severe errors.

  6. Bronchial fistula closure with negative pressure wound therapy: a feasible and cost-effective treatment.

    PubMed

    Nunes, Rodrigo Barboza; Müller, Bruno Francisco; Cipriano, Federico Enrique Garcia; Coltro, Pedro Soler; Farina, Jayme Adriano

    2016-01-01

    Treatment of bronchial fistula (BF) after pulmonary lobectomy is a challenge. Often, patients require long hospital stay, have recurrent empyema and pneumonia, are susceptible to sepsis, often need broad-spectrum antibiotics, as well as various surgical approaches. With the advent and growing evidence of the benefits of negative pressure therapy (NPT), its use in some patients with BF has been reported with encouraging results concerning its feasibility and cost-effectiveness. The aim of this study was to demonstrate the application of NPT as a resource for BF treatment and comparatively analyze the overall cost of treatment. RESUMO O tratamento de fístula brônquica (FB) após lobectomia pulmonar é um desafio. Muitas vezes, o paciente demanda longo tempo de internação, apresenta recidivas de empiema e pneumonia, pode evoluir para sepse, frequentemente necessita de antibioticoterapia de amplo espectro, bem como de várias abordagens cirúrgicas. Com o advento e acúmulo de evidências dos benefícios da terapia por pressão negativa (TPN), seu uso em alguns pacientes com FB tem sido relatado com resultados animadores relativos à sua viabilidade e ao seu custo-efetividade. O objetivo deste estudo foi demonstrar a aplicação de TPN como recurso para tratamento da FB e analisar comparativamente o custo global do seu tratamento.

  7. Tão perto de casa, tão longe de nós: etnografia das novas margens no centro da urbe

    PubMed Central

    Fernandes, Por Luís

    2011-01-01

    Philippe Bourgois é, desde 2007, “Richard Perry University professor” no Departamento de Antropologia e de Medicina Familiar e de Práticas Comunitárias na Universidade da Pensilvânia. Esteve durante largos anos ligado ao Departamento de Antropologia, História e Medicina Social da Universidade da Califórnia, São Francisco. A publicação, em 1995, de In Search of Respect: Selling Crack in El Barrio1 projectaria o seu nome muito para além dos Estados Unidos: uma etnografia no coração porto-riquenho do Harlem, em torno dos actores e dos ambientes da venda de crack. Seguir-se-ia um longo trabalho de terreno em acampamentos de dependentes de heroína em São Francisco, orientando o seu trabalho para as formas mais radicais da pobreza e da marginalidade nos EUA. É deste trabalho de terreno que sai o seu último livro, Righteous Dopefiend2. Em Junho de 2007 esteve em Lisboa para participar na 3.a edição do “Ethnografeast”. Foi então que aproveitámos a oportunidade para ouvir um percurso invulgar contado pelo próprio: uma longa conversa no Hotel Zurique, cujo nome só vem ao caso por evocar o país onde passou uma parte da infância. PMID:22013286

  8. Legitimizing Security in the Ivory Tower: Canadian University Corporate Security Services' Public Quest for Legitimacy.

    PubMed

    Wilkinson, Blair

    2016-05-01

    This article examines how university corporate security (UCS) services engage in legitimation work in their attempts to make their university communities (i.e., faculty, staff, students) and political masters (i.e., university administrators, boards of governors, senators) believe that they are honest, trustworthy, and caring and have authority that should be deferred to. This is accomplished through the analysis of interview and observational data collected as part of a research project exploring UCS services at five Canadian universities and an examination of how UCS services at 14 Canadian universities communicate using the social media service Twitter. These UCS services were found to primarily use Twitter for the purposes of soliciting or requesting information and for networking. In communicating through Twitter, UCS services engage in public legitimation work in which they make claims about and attempt to demonstrate their expertise, authority, and accountability. This article argues that both UCS services' particular legitimacy problem (i.e., their possession of both private and public attributes) and the interactive nature of public legitimation work create tensions that may serve to disrupt UCS services' ability to attain legitimacy. Cet article examine la manière dont les services de sécurité d'entreprise à l'université (SEU) s'engagent à légitimer leurs tentatives de persuader leurs communautés universitaires (c'est-à-dire le corps professoral, le personnel et les étudiants) ainsi que la haute administration (c'est-à-dire les administrateurs de l'université, le conseil des gouverneurs et les sénateurs) qu'ils sont honnêtes, attentifs, dignes de confiance, et qu'ils possèdent un niveau d'autorité auquel quiconque devrait se référer. Ceci sera accompli en analysant un corpus d'entrevues et d'observations dans le cadre d'un projet de recherche examinant les services de type SEU dans cinq universités canadiennes, ainsi qu'une étude sur

  9. Solar and Galactic Cosmic Rays Observed by SOHO

    NASA Astrophysics Data System (ADS)

    Curdt, W.; Fleck, B.

    Both the Cosmic Ray Flux (CRF) and Solar Energetic Particles (SEPs) have left an imprint on SOHO technical systems. While the solar array efficiency degraded irreversibly down to ≈77% of its original level over roughly 1 1/2 solar cycles, Single Event Upsets (SEUs) in the solid state recorder (SSR) have been reversed by the memory protection mechanism. We compare the daily CRF observed by the Oulu station with the daily SOHO SEU rate and with the degradation curve of the solar arrays. The Oulu CRF and the SOHO SSR SEU rate are both modulated by the solar cycle and are highly correlated, except for sharp spikes in the SEU rate, caused by isolated SEP events, which also show up as discontinuities in the otherwise slowly decreasing solar ray efficiency. This allows to discriminate between effects with solar and non-solar origin and to compare the relative strength of both. We find that during solar cycle 23 (1996 Apr 1 -- 2008 Aug 31) only 6% of the total number of SSR SEUs were caused by SEPs; the remaining 94% were due to galactic cosmic rays. During the maximum period of cycle 23 (2000 Jan 1 -- 2003 Dec 31), the SEP contribution increased to 22%, and during 2001, the year with the highest SEP rate, to 30%. About 40% of the total solar array degradation during the 17 years from Jan 1996 through Feb 2013 can be attributed to proton events, i.e. the effect of a series of short-lived, violent SEP events is comparable to the cycle-integrated damage by cosmic rays.

  10. Radiation characterization report for the GPS Receiver microcontroller chip

    NASA Astrophysics Data System (ADS)

    1994-06-01

    The overall objective of this characterization test was to determine the sensitivity of the Motorola 68332 32-bit microcontroller to radiation induced single event upset and latch-up (SEU/SEL). The microcontroller is a key component of the GPS Receiver which will be a subsystem of the satellite required for the 'FORTE' experiment. Testing was conducted at the Single Event Effects Laboratory at Brookhaven National Laboratory. The results obtained included a latch-up (SEL) threshold LET (Linear Energy Transfer) of 20 MeV-sq cm/mg and an upset (SEU) threshold LET of 5 MeV-sq cm/mg. The SEU threshold is typical of this technology, commercial 0.8 micrometers HCMOS. Some flow errors were observed that were not reset by the internal watchdog timer of the 68332. It is important that the Receiver design include a monitor of the device, such as an external watch-dog timer, that would initiate a reset of the program when this type of upset occurs. The SEL threshold is lower than would be expected for this 12 micrometer epi layer process and suggests the need for a strategy that would allow for a hard reset of the controller when a latch-up event occurs. Analysis of the galactic cosmic ray spectrum for the FORTE orbit was done and the results indicate a worst case latch-up rate for this device of 6.3 x 10(exp -5) latch-ups per device day or roughly one latch-up per 43.5 device years.

  11. Reconfigurable fault tolerant avionics system

    NASA Astrophysics Data System (ADS)

    Ibrahim, M. M.; Asami, K.; Cho, Mengu

    This paper presents the design of a reconfigurable avionics system based on modern Static Random Access Memory (SRAM)-based Field Programmable Gate Array (FPGA) to be used in future generations of nano satellites. A major concern in satellite systems and especially nano satellites is to build robust systems with low-power consumption profiles. The system is designed to be flexible by providing the capability of reconfiguring itself based on its orbital position. As Single Event Upsets (SEU) do not have the same severity and intensity in all orbital locations, having the maximum at the South Atlantic Anomaly (SAA) and the polar cusps, the system does not have to be fully protected all the time in its orbit. An acceptable level of protection against high-energy cosmic rays and charged particles roaming in space is provided within the majority of the orbit through software fault tolerance. Check pointing and roll back, besides control flow assertions, is used for that level of protection. In the minority part of the orbit where severe SEUs are expected to exist, a reconfiguration for the system FPGA is initiated where the processor systems are triplicated and protection through Triple Modular Redundancy (TMR) with feedback is provided. This technique of reconfiguring the system as per the level of the threat expected from SEU-induced faults helps in reducing the average dynamic power consumption of the system to one-third of its maximum. This technique can be viewed as a smart protection through system reconfiguration. The system is built on the commercial version of the (XC5VLX50) Xilinx Virtex5 FPGA on bulk silicon with 324 IO. Simulations of orbit SEU rates were carried out using the SPENVIS web-based software package.

  12. On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

    NASA Astrophysics Data System (ADS)

    Seferis, I. E.; Zeler, J.; Michail, C.; Valais, I.; Fountos, G.; Kalyvas, N.; Bakas, A.; Kandarakis, I.; Zych, E.

    2016-05-01

    In the present work, we demonstrate the fabrication technique of highly translucent layers of nanoparticulated (~50 nm) LuPO4:Eu phosphor, present their basic luminescent properties and give results of their performance in a planar imaging system coupled to a CMOS photodetector. For comparison, the imaging performance of an opaque Gd2O2S:Eu phosphor screen prepared by sedimentation is also shown. The X-ray detection parameters as well as the luminescence efficiency of the investigated films were discussed. Results show that the in-line transmittance at ~600-700 nm, in the range of the phosphor luminescence, varies with respect to the thickness of the films from 40 to 50 % for a film of 67 μm thick to 4-12 % when the thickness increases to 460 μm. Yet, X-ray detection parameters get enhanced as the thickness of the films increases. Those results affect the luminescence efficiency curves of the films under poly-energetic X-ray radiation of various tube energies. The normalized noise power spectrum values were found similar for LuPO4:Eu films and a phosphor screen made using commercial Gd2O2S:Eu powder. The detective quantum efficiency of our films is clearly lower compared to the Gd2O2S:Eu screen from 2 to 10 cycles mm-1 frequency range while the modulation transfer function is lower from 0 to 5.5 cycles mm-1 frequency range. The acquired data allow to predict that high-temperature sintering of our films under pressure may help to improve their imaging quality, since such a processing should increase the luminescence efficiency without significant growth of the grains and thus without sacrificing their translucent character.

  13. Characterization of LT GaAs carrier lifetime in multilayer GaAs epitaxial wafers by the transient reflectivity technique

    SciTech Connect

    McMorrow, D.; Melinger, J.S.; Campbell, A.B.; Knudson, A.R.; Buchner, S.; Ikossi-Anastasiou, K.; Moss, S.C.; Engelhardt, D.; Childs, T.

    1997-12-01

    A methodology for determining the carrier lifetime of LT GaAs buffer layers in GaAs multilayer wafers utilizing the femtosecond transient reflectivity technique is introduced. Experimental results and computer simulations performed as a function of the LT GaAs growth temperature are presented for the multilayer GaAs structures that are used for device fabrication. The markedly non-exponential nature of the measured transients is a consequence of the multilayer structure of the wafers. The carrier lifetime measurements are correlated with available SEU data measured for structures fabricated with LT GaAs buffers with different growth temperatures.

  14. A 1.2 Gb/s Data Transmission Unit in CMOS 0.18 μm technology for the ALICE Inner Tracking System front-end ASIC

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Aglieri Rinella, G.; Benotto, F.; Corrales Morales, Y.; Kugathasan, T.; Lattuca, A.; Lupi, M.; Ravasenga, I.

    2017-02-01

    The upgrade of the ALICE Inner Tracking System is based on a Monolithic Active Pixel Sensor and ASIC designed in a CMOS 0.18 μ m process. In order to provide the required output bandwidth (1.2 Gb/s for the inner layers and 400 Mb/s for the outer ones) on a single high speed serial link, a custom Data Transmission Unit (DTU) has been developed in the same process. The DTU includes a clock multiplier PLL, a double data rate serializer and a pseudo-LVDS driver with pre-emphasis and is designed to be SEU tolerant.

  15. Effects of cosmic rays on single event upsets

    NASA Astrophysics Data System (ADS)

    Venable, D. D.; Zajic, V.; Lowe, C. W.; Olidapupo, A.; Fogarty, T. N.

    1989-02-01

    Assistance was provided to the Brookhaven Single Event Upset (SEU) Test Facility. Computer codes were developed for fragmentation and secondary radiation affecting Very Large Scale Integration (VLSI) in space. A computer controlled CV (HP4192) test was developed for Terman analysis. Also developed were high speed parametric tests which are independent of operator judgment and a charge pumping technique for measurement of Dit (E). The X-ray secondary effects, and parametric degradation as a function of dose rate were simulated. The SPICE simulation of static RAMs with various resistor filters was tested.

  16. Speech Processing.

    DTIC Science & Technology

    1983-05-01

    airborne environment. The SEU’s ability to remove narrowband types of noises automatically and in real-time by as much as forty (40) d& decibels would...cepstral process that can improve the signal-to-noise ratio of noisy communication channels as much as 12 to 14 decibels . An improvement of this amount in...and Forgie, C.A., 1959, "Results Obtained from a Vowel Recognition Computer Program", J. Acoust Soc. Am 31(11) 8. Vicens, P. 1969, "Aspects of

  17. A machine independent expert system for diagnosing environmentally induced spacecraft anomalies

    NASA Technical Reports Server (NTRS)

    Rolincik, Mark J.

    1991-01-01

    A new rule-based, machine independent analytical tool for diagnosing spacecraft anomalies, the EnviroNET expert system, was developed. Expert systems provide an effective method for storing knowledge, allow computers to sift through large amounts of data pinpointing significant parts, and most importantly, use heuristics in addition to algorithms which allow approximate reasoning and inference, and the ability to attack problems not rigidly defines. The EviroNET expert system knowledge base currently contains over two hundred rules, and links to databases which include past environmental data, satellite data, and previous known anomalies. The environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose.

  18. Insertion Demonstrations of Digital Gallium Arsenide. OBP-80 Final Technical Report. Volume 1. Chip Set Schematics

    DTIC Science & Technology

    1992-01-01

    Jul 91 Drawing Number: 849GOBP 100 -J_ --- ’ 0 -1 no - 5 CD W - - 3 WD u- U - - I-- U - C3 Figure 3 VOTEREG Macrocell Schematic Diagram Martin Marietta...the SEU current pulse at differnt points in the circuit. If the current pulse is deposited on the 2.2 pF output node of the VOTEBIT register, no upset...proportional to the operating clock speed. This follows since the scrub repition rate is increasing, and there appear to be no single points of sensitivity. The

  19. Radiation Issues and Applications of Floating Gate Memories

    NASA Technical Reports Server (NTRS)

    Scheick, L. Z.; Nguyen, D. N.

    2000-01-01

    The radiation effects that affect various systems that comprise floating gate memories are presented. The wear-out degradation results of unirradiated flash memories are compared to irradiated flash memories. The procedure analyzes the failure to write and erase caused by wear-out and degradation of internal charge pump circuits. A method is described for characterizing the radiation effects of the floating gate itself. The rate dependence, stopping power dependence, SEU susceptibility and applications of floating gate in radiation environment are presented. The ramifications for dosimetry and cell failure are discussed as well as for the long term use aspects of non-volatile memories.

  20. Doubly Rotated Cut SAW Devices.

    DTIC Science & Technology

    1981-04-01

    AD-AO 545 MOTOROLA INC SCOTTSDALE AZ GOVERNMENT ELECTRONICS DIV F/O 20/2 DOUBLY ROTATED CUT SAW DEVICES.( U) APR 81 0 F WILLIAMS, F Y CHO DAAK2O 79...f we Ma. he0 _TL ft . *VM or seu3f? 6 090100 cove mis interim Report.~arch 198 ’ Doubly Rotated Cut SAW Devices .r etme 9 9. SInFY T ON 6MNY mUUUUf L...exploratory development of doubly rotated cuts of quartz possessing superior Surface Acoustic Wave (SAW) properties for applications involving

  1. Right hepatic artery aneurysm.

    PubMed

    Bernal, Astrid Del Pilar Ardila; Loures, Paulo; Calle, Juan Cristóbal Ospina; Cunha, Beatriz; Córdoba, Juan Camilo

    2016-01-01

    We report a case of an aneurysm of the right hepatic artery and its multidisciplinary management by general surgery, endoscopy and radiology services. Being a case of extremely low incidence, it is important to show its diagnostic and therapeutic approach. RESUMO Relatamos um caso de aneurisma da artéria hepática direita conduzido de forma multidisciplinar pelos Serviços de Cirurgia Geral, Endoscopia e Radiologia. Em se tratando de caso de incidência baixíssima, é importante mostrar o enfoque diagnóstico e terapêutico usado em seu manejo.

  2. AVR microcontroller simulator for software implemented hardware fault tolerance algorithms research

    NASA Astrophysics Data System (ADS)

    Piotrowski, Adam; Tarnowski, Szymon; Napieralski, Andrzej

    2008-01-01

    Reliability of new, advanced electronic systems becomes a serious problem especially in places like accelerators and synchrotrons, where sophisticated digital devices operate closely to radiation sources. One of the possible solutions to harden the microprocessor-based system is a strict programming approach known as the Software Implemented Hardware Fault Tolerance. Unfortunately, in real environments it is not possible to perform precise and accurate tests of the new algorithms due to hardware limitation. This paper highlights the AVR-family microcontroller simulator project equipped with an appropriate monitoring and the SEU injection systems.

  3. Scaling and Single Event Effects (SEE) Sensitivity

    NASA Technical Reports Server (NTRS)

    Oldham, Timothy R.

    2003-01-01

    This paper begins by discussing the potential for scaling down transistors and other components to fit more of them on chips in order to increasing computer processing speed. It also addresses technical challenges to further scaling. Components have been scaled down enough to allow single particles to have an effect, known as a Single Event Effect (SEE). This paper explores the relationship between scaling and the following SEEs: Single Event Upsets (SEU) on DRAMs and SRAMs, Latch-up, Snap-back, Single Event Burnout (SEB), Single Event Gate Rupture (SEGR), and Ion-induced soft breakdown (SBD).

  4. Analysis of space radiation data of semiconductor memories

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Brucker, G. J.; Stauffer, C. A.

    1996-01-01

    This article presents an analysis of radiation effects for several select device types and technologies aboard the Combined Release and Radiation Effects Satellite (CRRES) satellite. These space-flight measurements covered a period of about 14 months of mission lifetime. Single Event Upset (SEU) data of the investigated devices from the Microelectronics Package (MEP) were processed and analyzed. Valid upset measurements were determined by correcting for invalid readings, hard failures, missing data tapes (thus voids in data), and periods over which devices were disabled from interrogation. The basic resolution time of the measurement system was confirmed to be 2 s. Lessons learned, important findings, and recommendations are presented.

  5. Development and Use of Anucleated Bacterial Cells to Assay the in vivo Activity of Pollutants

    DTIC Science & Technology

    1985-07-31

    the imune precipitate only. A 2 - +e2nd objective proved more fruitful. We have been able to successfully identify the cysteine substitution sites in...Unnece E. co + omlsrma .ar lc -Unnece ol + imun seu 4 .sr 2a - netdE cl omlseu .aru ’.𔃾 2-T7ifce o 1+abob imue.4. I+S Pru 2c -- , V i lb -UVinfected E...coli + ase immune serum 2 + S. aureus 2e T7 infected E. coli + imune serum 2 + S. aureus

  6. Neuroprotective effects of Buyang Huanwu decoction on cerebral ischemia-induced neuronal damage

    PubMed Central

    Mu, Qingchun; Liu, Pengfei; Hu, Xitong; Gao, Haijun; Zheng, Xu; Huang, Haiyan

    2014-01-01

    Among the various treatment methods for stroke, increasing attention has been paid to traditional Chinese medicines. Buyang Huanwu decoction is a commonly used traditional Chinese medicine for the treatment of stroke. This paper summarizes the active components of the Chinese herb, which is composed of Huangqi (Radix Astragali seu Hedysari), Danggui (Radix Angelica sinensis), Chishao (Radix Paeoniae Rubra), Chuanxiong (Rhizoma Ligustici Chuanxiong), Honghua (Flos Carthami), Taoren (Semen Persicae) and Dilong (Pheretima), and identifies the therapeutic targets and underlying mechanisms that contribute to the neuroprotective properties of Buyang Huanwu decoction. PMID:25368650

  7. CRRES Microelectronics Test Package (MEP)

    NASA Astrophysics Data System (ADS)

    Mullen, E. G.; Ray, K. P.

    1993-04-01

    The Microelectronics Test Package (MEP) flown on board the Combined Release and Radiation Effects Satellite (CRRES) contained over 60 device types and approximately 400 total devices which were tested for both single event upset (SEU) and total dose (parametric degradation and annealing). A description of the experiment, the method of testing devices, and the structure of data acquisition are presented. Sample flight data are shown. These included SEUs from a GaAs 1 K RAM during the March 1991 solar flare, and a comparison between passive shielding and a specially designed spot shielding package.

  8. CRRES microelectronics test package (MEP)

    SciTech Connect

    Mullen, E.G.; Ray, K.P. )

    1993-04-01

    The Microelectronics Test Package (MEP) flown on board the Combined Release and Radiation Effects Satellite (CRRES) contained over 60 device types and approximately 400 total devices which were tested for both single event upset (SEU) and total dose (parametric degradation and annealing). A description of the experiment, the method of testing devices, and the structure of data acquisition are presented. Sample flight data are shown. These included SEUs from a GaAs 1 K RAM during the March 1991 solar flare, and a comparison between passive shielding and a specially designed spot shielding package.

  9. The Imagine the Universe! E/PO Program

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    Since 1996, the Imagine the Universe! E/PO program has brought information and curriculum support materials to upper middle school, high school, and lower undergraduate students and their teachers on topics in the Structure and Evolution of the Universe (SEU) theme. The Imagine E/PO program consists of a web site, a series of posters and information/activity booklets, and a repertoire of educator workshops. We involve both scientists and educators in the development and testing of the materials. We describe here the various aspects of this program.

  10. Advanced flight computer. Special study

    NASA Technical Reports Server (NTRS)

    Coo, Dennis

    1995-01-01

    This report documents a special study to define a 32-bit radiation hardened, SEU tolerant flight computer architecture, and to investigate current or near-term technologies and development efforts that contribute to the Advanced Flight Computer (AFC) design and development. An AFC processing node architecture is defined. Each node may consist of a multi-chip processor as needed. The modular, building block approach uses VLSI technology and packaging methods that demonstrate a feasible AFC module in 1998 that meets that AFC goals. The defined architecture and approach demonstrate a clear low-risk, low-cost path to the 1998 production goal, with intermediate prototypes in 1996.

  11. [Traumatic injuries of deciduous teeth].

    PubMed

    Hidasi, G

    2001-06-01

    Review of literature regarding frequency of traumatic injuries of primary teeth, types of injuries, therapy and possible consequences in permanent dentition. The diagram of prevalence shows no direct correlation to age, whereas according to diagram of incidence 70% of injuries occur in the second and third years of life. Injuries without dislocation of the deciduous tooth: fractura coronae dentis decidui, contusio seu concussio dentis decidui, fractura radicis decidui. Injuries with dislocation: luxatio totalis dentis decidui, luxatio partialis dentis decidui, intrusio dentis decidui. Consequences of traumas can be detected in disturbances of second dentition, in developmental anomalies of enamel and in considerable deformities of homologous permanent tooth.

  12. Experimental studies of single-event effects induced by heavy ions

    NASA Astrophysics Data System (ADS)

    Liu, J.; Hou, M. D.; Li, B. Q.; Liu, C. L.; Wang, Z. G.; Cheng, S.; Sun, Y. M.; Jin, Y. F.; Lin, Y. L.; Cai, J. R.; Wang, S. J.; Ye, Z. H.; Zhu, G. W.; Du, H.; Ren, Q. Y.; Wu, W.; Mao, X. M.; Sun, Y. Q.; Guo, R.

    2000-04-01

    This paper presents the results of ground-based heavy ion test of single-event effect (SEE) vulnerability on microcircuits used in space. We observed the dependence of upset cross-sections on the incident angle of ions in Intel 8086 CPU. SEU cross-sections of various SRAMs did not depend on the stored pattern, but 0→1 and 1→0 transitions were completely different for different manufacturer products. Some SEE protection methods were verified in conditions of ground simulation experiments.

  13. Frequency Dependence of Single-event Upset in Advanced Commerical PowerPC Microprocessors

    NASA Technical Reports Server (NTRS)

    Irom, Frokh; Farmanesh, Farhad F.; Swift, Gary M.; Johnston, Allen H.

    2004-01-01

    This paper examines single-event upsets in advanced commercial SOI microprocessors in a dynamic mode, studying SEU sensitivity of General Purpose Registers (GPRs) with clock frequency. Results are presented for SOI processors with feature sizes of 0.18 microns and two different core voltages. Single-event upset from heavy ions is measured for advanced commercial microprocessors in a dynamic mode with clock frequency up to 1GHz. Frequency and core voltage dependence of single-event upsets in registers is discussed.

  14. Radiation Issues and Applications of Floating Gate Memories

    NASA Technical Reports Server (NTRS)

    Scheick, L. Z.; Nguyen, D. N.

    2000-01-01

    The radiation effects that affect various systems that comprise floating gate memories are presented. The wear-out degradation results of unirradiated flash memories are compared to irradiated flash memories. The procedure analyzes the failure to write and erase caused by wear-out and degradation of internal charge pump circuits. A method is described for characterizing the radiation effects of the floating gate itself. The rate dependence, stopping power dependence, SEU susceptibility and applications of floating gate in radiation environment are presented. The ramifications for dosimetry and cell failure are discussed as well as for the long term use aspects of non-volatile memories.

  15. Analysis of space radiation data of semiconductor memories.

    PubMed

    Stassinopoulos, E G; Brucker, G J; Stauffer, C A

    1996-11-01

    This article presents an analysis of radiation effects for several select device types and technologies aboard the Combined Release and Radiation Effects Satellite (CRRES) satellite. These space-flight measurements covered a period of about 14 months of mission lifetime. Single Event Upset (SEU) data of the investigated devices from the Microelectronics Package (MEP) were processed and analyzed. Valid upset measurements were determined by correcting for invalid readings, hard failures, missing data tapes (thus voids in data), and periods over which devices were disabled from interrogation. The basic resolution time of the measurement system was confirmed to be 2 s. Lessons learned, important findings, and recommendations are presented.

  16. Inorganic scintillation detectors based on Eu-activated phosphors for 192Ir brachytherapy

    NASA Astrophysics Data System (ADS)

    Kertzscher, Gustavo; Beddar, Sam

    2017-06-01

    The availability of real-time treatment verification during high-dose-rate (HDR) brachytherapy is currently limited. Therefore, we studied the luminescence properties of the widely commercially available scintillators using the inorganic materials Eu-activated phosphors Y2O3:Eu, YVO4:Eu, Y2O2S:Eu, and Gd2O2S:Eu to determine whether they could be used to accurately and precisely verify HDR brachytherapy doses in real time. The suitability for HDR brachytherapy of inorganic scintillation detectors (ISDs) based on the 4 Eu-activated phosphors in powder form was determined based on experiments with a 192Ir HDR brachytherapy source. The scintillation intensities of the phosphors were 16-134 times greater than that of the commonly used organic plastic scintillator BCF-12. High signal intensities were achieved with an optimized packing density of the phosphor mixture and with a shortened fiber-optic cable. The influence of contaminating Cerenkov and fluorescence light induced in the fiber-optic cable (stem signal) was adequately suppressed by inserting between the fiber-optic cable and the photodetector a 25 nm band-pass filter centered at the emission peak. The spurious photoluminescence signal induced by the stem signal was suppressed by placing a long-pass filter between the scintillation detector volume and the fiber-optic cable. The time-dependent luminescence properties of the phosphors were quantified by measuring the non-constant scintillation during irradiation and the afterglow after the brachytherapy source had retracted. We demonstrated that a mixture of Y2O3:Eu and YVO4:Eu suppressed the time-dependence of the ISDs and that the time-dependence of Y2O2S:Eu and Gd2O2S:Eu introduced large measurement inaccuracies. We conclude that ISDs based on a mixture of Y2O3:Eu and YVO4:Eu are promising candidates for accurate and precise real-time verification technology for HDR BT that is cost effective and straightforward to manufacture. Widespread dissemination of this

  17. NASA Space Engineering Research Center for VLSI systems design

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This annual review reports the center's activities and findings on very large scale integration (VLSI) systems design for 1990, including project status, financial support, publications, the NASA Space Engineering Research Center (SERC) Symposium on VLSI Design, research results, and outreach programs. Processor chips completed or under development are listed. Research results summarized include a design technique to harden complementary metal oxide semiconductors (CMOS) memory circuits against single event upset (SEU); improved circuit design procedures; and advances in computer aided design (CAD), communications, computer architectures, and reliability design. Also described is a high school teacher program that exposes teachers to the fundamentals of digital logic design.

  18. Radiation Testing, Characterization and Qualification Challenges for Modern Microelectronics and Photonics Devices and Technologies

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Cohn, Lewis M.

    2008-01-01

    At GOMAC 2007, we discussed a selection of the challenges for radiation testing of modern semiconductor devices focusing on state-of-the-art memory technologies. This included FLASH non-volatile memories (NVMs) and synchronous dynamic random access memories (SDRAMs). In this presentation, we extend this discussion in device packaging and complexity as well as single event upset (SEU) mechanisms using several technology areas as examples including: system-on-a-chip (SOC) devices and photonic or fiber optic systems. The underlying goal is intended to provoke thought for understanding the limitations and interpretation of radiation testing results.

  19. Effects of cosmic rays on single event upsets

    NASA Technical Reports Server (NTRS)

    Venable, D. D.; Zajic, V.; Lowe, C. W.; Olidapupo, A.; Fogarty, T. N.

    1989-01-01

    Assistance was provided to the Brookhaven Single Event Upset (SEU) Test Facility. Computer codes were developed for fragmentation and secondary radiation affecting Very Large Scale Integration (VLSI) in space. A computer controlled CV (HP4192) test was developed for Terman analysis. Also developed were high speed parametric tests which are independent of operator judgment and a charge pumping technique for measurement of D(sub it) (E). The X-ray secondary effects, and parametric degradation as a function of dose rate were simulated. The SPICE simulation of static RAMs with various resistor filters was tested.

  20. Arboviruses emerging in Brazil: challenges for clinic and implications for public health.

    PubMed

    Donalisio, Maria Rita; Freitas, André Ricardo Ribas; Zuben, Andrea Paula Bruno Von

    2017-04-10

    Arboviruses have been emerging in different parts of the world due to genetic changes in the virus, alteration of the host and vector population dynamics, or because of anthropogenic environmental factors. These viruses' capacity for adaptation is notable, as well as the likelihood of their emergence and establishment in new geographic areas. In Brazilian epidemiologic scenario, the most common arboviruses are DENV, CHIKV, and ZIKV, although others may spread in the country. Little is yet known of the impact of viral co-circulation, which would theoretically result in more intense viremia or other immunological alterations that could trigger autoimmune diseases, such as Guillain-Barré syndrome. The impact on morbidity and mortality intensifies as extensive epidemics lead to a high number of affected individuals, severe cases, and implications for health services, mainly due to the absence of treatment, vaccines, and effective prevention and control measures. RESUMO Notifica-se a emergência de arboviroses em diferentes regiões do planeta em decorrência de mudanças genéticas no vírus, alteração da dinâmica populacional de hospedeiros e vetores ou por fatores ambientais de origem antropogênica. É notável a capacidade de adaptação desses vírus e a possibilidade de emergirem e se estabelecerem em novas áreas geográficas. No contexto epidemiológico brasileiro, os arbovírus de maior circulação são DENV, CHIKV e ZIKV, embora existam outros com potencial de disseminação no País. O impacto da cocirculação viral ainda é pouco conhecido, a qual teoricamente resultaria em viremias mais intensas ou outras alterações imunológicas que poderiam ser o gatilho para doenças autoimunes, como a síndrome de Guillain-Barré. O impacto na morbidade e mortalidade se intensifica à medida que extensas epidemias pressupõem grande número de indivíduos acometidos, casos graves e implicações sobre os serviços de saúde, principalmente diante da aus

  1. Gigabit optical link test system for RPC muon trigger in the CMS experiment

    NASA Astrophysics Data System (ADS)

    Pozniak, Krzysztof T.; Ptak, Mariusz; Romaniuk, Ryszard S.; Kierzkowski, Krzysztof; Kudla, Ignacy M.; Pietrusinski, Michal; Wrochna, Grzegorz; Banzuzi, Kukka; Ungaro, Donatella

    2003-10-01

    High-energy experiments like Atlas, Alice, CMS or LHCb at the LHC accelerator at CERN will be performed in very harsh conditions for electronic equipment. High radiation level in the experimental halls causes that commonly available electronic devices do not work properly. A specialized optical transmitter--GOL (Gigabit Optical Link) has been designed at CERN to meet the radiation environment requirements. The design goal was to supply device resistant to high radiation, fast, and being able to transmit data through optical links. Transmitter was designed considering two important characteristics of its work environment: high radiation level and gigabit transmission speed. Proper internal structure of GOL chip allows to minimize single event upsets (SEU) caused by ionizing radiation. Unfortunately, the design does not elimiate SEU completely. This paper presents testing system for the GOL. Its main purpose is testing new prototypes of optical fiber gigabit transmission systems using GOL transmitter and commercial receiver components. The system will be implemented in the CMS experiment for control purposes. It will monitor optical link and transmission quality in the RPC detector. System consits of hardware layer and software layer. Hardware layer, based on Latera FPGA programmable devices. Software has been developed using C++ environment integrated with VME controller hardware.

  2. Monte Carlo simulation of an x-ray luminescence optical tomography scanner prototype

    SciTech Connect

    Rosas-González, S. E-mail: arnulfo@fisica.unam.mx; Martínez-Dávalos, A. E-mail: arnulfo@fisica.unam.mx; Rodríguez-Villafuerte, M. E-mail: arnulfo@fisica.unam.mx; Murrieta-Rodríguez, T. E-mail: arnulfo@fisica.unam.mx

    2014-11-07

    In this work we report the calculation of the deposited energy distribution produced by an x-ray luminescence optical tomography (XLOT) system in a phantom containing different concentrations of Gd{sub 2}O{sub 2}S:Eu nanoparticles. The calculations were performed via Monte Carlo simulation considering spectra from a W target x-ray tube operating between 30 and 90 kVp, with 1.0 mm Al added filtration. CT and XLOT tomographic images were reconstructed from the same data. The results show that XLOT has better detectability than CT alone, that the dose scales linearly with kVp for a fixed concentration of Gd{sub 2}O{sub 2}S:Eu and air-kerma rate, the scattered radiation contribution to the total dose and signal is about 20% and that the dose ratio for a 3 mm diameter insert containing 10 mg/ml Gd{sub 2}O{sub 2}S embedded in a 30 mm diameter water phantom is 6:1. This ratio drops to less than 2:1 for a 1 mg/ml concentration. Finally we show that the method of conjugate images can be used to correct for artifacts due to attenuation effects in XLOT images.

  3. Development of a radiation-hardened SRAM with EDAC algorithm for fast readout CMOS pixel sensors for charged particle tracking

    NASA Astrophysics Data System (ADS)

    Wei, X.; Li, B.; Chen, N.; Wang, J.; Zheng, R.; Gao, W.; Wei, T.; Gao, D.; Hu, Y.

    2014-08-01

    CMOS pixel sensors (CPS) are attractive for use in the innermost particle detectors for charged particle tracking due to their good trade-off between spatial resolution, material budget, radiation hardness, and readout speed. With the requirements of high readout speed and high radiation hardness to total ionizing dose (TID) for particle tracking, fast readout CPS are composed by integrating a data compression block and two SRAM IP cores. However, the radiation hardness of the SRAM IP cores is not as high as that of the other parts in CPS, and thus the radiation hardness of the whole CPS chip is lowered. Especially, when CPS are migrated into 0.18-μm processes, the single event upset (SEU) effects should be also considered besides TID and single event latchup (SEL) effects. This paper presents a radiation-hardened SRAM with enhanced radiation hardness to SEU. An error detection and correction (EDAC) algorithm and a bit-interleaving storage strategy are adopted in the design. The prototype design has been fabricated in a 0.18-μm process. The area of the new SRAM is increased 1.6 times as compared with a non-radiation-hardened SRAM due to the integration of EDAC algorithm and the adoption of radiation hardened layout. The access time is increased from 5 ns to 8 ns due to the integration of EDAC algorithm. The test results indicate that the design satisfy requirements of CPS for charged particle tracking.

  4. Contemporary Issues in Ultra-Low Alpha Particle Counting

    NASA Astrophysics Data System (ADS)

    Gordon, Michael

    Single-Event Upsets (SEU) in CMOS devices are caused by the passage of ionizing radiation either from terrestrial neutrons or from the natural alpha particle radiation within the materials surrounding the transistors. Interactions of the neutrons with the silicon cause spallation reactions which emit energetic highly ionizing elements. Alpha particles, on the other hand, can upset the devices through direct ionization rather than through a nuclear reaction as in the case of the neutrons. In order to minimize the alpha-particle component of SEU, the radiation from the materials within a distance 100 μm of the transistors, currently needs to have an alpha particle emissivity of less than 2 alpha particles per khr per square centimeter. Many alpha particle detectors have background levels that are larger than this, which can make these measurements inaccurate and time consuming. This talk will discuss what is involved in making alpha particle emissivity measurements of materials used in the semiconductor industry using an ultra-low background commercially-available ionization detector. Detector calibration and efficiency, radon adsorption on the samples, and the effect of surface charge on electrically insulating samples will be discussed.

  5. Synthesis and characterization of flexible thermographic phosphor temperature sensors

    NASA Astrophysics Data System (ADS)

    Mitchell, Katherine E.; Gardner, Victor; Allison, Stephen W.; Sabri, Firouzeh

    2016-10-01

    The temperature dependence of the emission characteristics of thermographic phosphors has been used extensively for surface temperature measurements of systems where thermal management is critical for the safe operation of the system. The instantaneous, remote, and highly accurate nature of this form of temperature measurement makes it a very attractive measurement technique. However, the destructive nature of depositing phosphors directly onto the surface of interest and the complications of working with fine powders has limited the use of this technique in all areas. This work focuses on the design and characterization of polymer-encapsulated thermographic phosphor flexible sensors for surface temperature assessment. La2O2S:Eu powder was embedded in an elastomeric sleeve at concentrations of 10%, 25%, and 50% wt. and fully characterized. The effect of spin-coating on emission characteristics of La2O2S:Eu was tested and the decay times were compared to results obtained from bulk-doped samples previously created by the authors.

  6. Injecting Artificial Memory Errors Into a Running Computer Program

    NASA Technical Reports Server (NTRS)

    Bornstein, Benjamin J.; Granat, Robert A.; Wagstaff, Kiri L.

    2008-01-01

    Single-event upsets (SEUs) or bitflips are computer memory errors caused by radiation. BITFLIPS (Basic Instrumentation Tool for Fault Localized Injection of Probabilistic SEUs) is a computer program that deliberately injects SEUs into another computer program, while the latter is running, for the purpose of evaluating the fault tolerance of that program. BITFLIPS was written as a plug-in extension of the open-source Valgrind debugging and profiling software. BITFLIPS can inject SEUs into any program that can be run on the Linux operating system, without needing to modify the program s source code. Further, if access to the original program source code is available, BITFLIPS offers fine-grained control over exactly when and which areas of memory (as specified via program variables) will be subjected to SEUs. The rate of injection of SEUs is controlled by specifying either a fault probability or a fault rate based on memory size and radiation exposure time, in units of SEUs per byte per second. BITFLIPS can also log each SEU that it injects and, if program source code is available, report the magnitude of effect of the SEU on a floating-point value or other program variable.

  7. Clinical reasoning in nursing: teaching strategies and assessment tools.

    PubMed

    Carvalho, Emília Campos de; Oliveira-Kumakura, Ana Railka de Souza; Morais, Sheila Coelho Ramalho Vasconcelos

    2017-01-01

    To present the concept and development of teaching strategies and the assessment tools regarding clinical reasoning for accurate practice. This is a theoretical reflection based on scientific studies. Comprehension of the essential concepts of the thought process and its articulation with the different teaching strategies and the assessment tools which has allowed presenting ways to improve the process of diagnostic or therapeutic clinical reasoning. The use of new strategies and assessment tools should be encouraged in order to contribute to the development of skills that lead to safe and effective decision making. Apresentar o conceito de raciocínio clínico, seu desenvolvimento, as estratégias para seu ensino e os instrumentos de avaliação para uma prática acurada. Trata-se de uma reflexão teórica fundamentada em estudos científicos. A compreensão dos conceitos essenciais do processo de pensamento e sua articulação com as diferentes estratégias de ensino e com os instrumentos de avaliação permitiram exemplificar meios de aprimorar o processo de raciocínio clínico diagnóstico ou terapêutico. A utilização de novas estratégias e instrumentos de avaliação deve ser estimulado para contribuir com o desenvolvimento das habilidades que culminam na tomada de decisão segura e eficaz.

  8. A comparison of two different types of geosynchronous statellite measurements during the 1989 solar proton events

    NASA Astrophysics Data System (ADS)

    Normand, E.

    1994-10-01

    The proton telescope aboard the Geostationary Operational Environmental Satellite (GOES-7) satellite continuously records the proton flux at geosynchronous orbit, and therefore provides a direct measurement of the energetic protons arriving during Solar Energetic Particle (SEP) events. Microelectronic devices are susceptible to Single Event Upset (SEU) caused by both energetic protons and Galactic Cosmic Ray (GCR) ions. Some devices are so sensitive that their upsets can be used as a dosimetric indicator of a high fluence of particles. The 93L422 1K Static Random Access Memory (SRAM) is one such device. Eight of them are on the Tracking and Data Relay Satellite-1 (TDRS-1) satellite in geosynchronous orbit, and collectively they had been experiencing 1-2 upset/day due to the GCR background. During the large SEP events of 1989 the upset rate increased dramatically, up to about 250 for the week of 19 Oct., due to the arrival of the SEP protons. Using the GOES proton spectra, the proton-induced SEU cross section curve for the 93L422 and the shielding distribution around the 93L422, the calculated upsets based on the GOES satellite data compared well against the log of measured upsets on TDRS-1.

  9. Light-Ion Production in the Interaction of 96 MeV Neutrons with Silicon

    NASA Astrophysics Data System (ADS)

    Tippawan, U.; Pomp, S.; Atac, A.; Bergenwall, B.; Blomgren, J.; Dangtip, S.; Hildebrand, A.; Johansson, C.; Klug, J.; Mermod, P.; Nilsson, L.; Österlund, M.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A. V.; Renberg, P.-U.; Nadel-Turonski, P.; Corcalciuc, V.; Watanabe, Y.; Koning, A. J.

    2005-05-01

    Radiation effects induced by terrestrial cosmic rays in microelectronics, on board aircrafts as well as at sea level, have recently attracted much attention. The most important particle radiation is due to spallation neutrons, created in the atmosphere by cosmic-ray protons. When, e.g., an electronic memory circuit is exposed to neutron radiation, charged particles can be produced in a nuclear reaction. The charge released by ionization can cause a flip of the memory content in a bit, which is called a single-event upset (SEU). This induces no hardware damage to the circuit, but unwanted re-programming of memories, CPUs, etc., can have consequences for the reliability, and ultimately also for the safety of the system. Data on energy and angular distributions of the secondary particles produced by neutrons in silicon nuclei are essential input for analyses and calculation of SEU rate. In this work, double-differential cross sections of inclusive light-ion (p, d, t, 3He and α) production in silicon, induced by 96 MeV neutrons, are presented. Energy distributions are measured at eight laboratory angles from 20° to 160° in steps of 20°. Deduced energy-differential and production cross sections are reported as well. Experimental cross sections are compared to theoretical reaction model calculations and existing experimental data in the literature.

  10. The influence of oxygen partial pressure on material properties of Eu3+-doped Y2O2S thin film deposited by Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Ali, A. G.; Dejene, B. F.; Swart, H. C.

    2016-01-01

    Eu3+-doping has been of interest to improve the luminescent characteristics of thin-film phosphors. Y2O2S:Eu3+ films have been grown on Si (100) substrates by using a Pulsed Laser Deposition technique. The thin films grown under different oxygen deposition pressure conditions have been characterized using structural and luminescent measurements. The X-ray diffraction patterns showed mixed phases of cubic and hexagonal crystal structures. As the oxygen partial pressure increased, the crystallinity of the films improved. Further increase of the O2 pressure to 140 mtorr reduced the crystallinity of the film. Similarly, both scanning electron microscopy and Atomic Force Microscopy confirmed that an increase in O2 pressure affected the morphology of the films. The average band gap of the films calculated from diffuse reflectance spectra using the Kubelka-Munk function was about 4.75 eV. The photoluminescence measurements indicated red emission of Y2O2S:Eu3+ thin films with the most intense peak appearing at 619 nm, which is assigned to the 5D0-7F2 transition of Eu3+. This most intense peak was totally quenched at higher O2 pressures. This phosphor may be a promising material for applications in the flat panel displays.

  11. High-Energy Electron-Induced SEUs and Jovian Environment Impact

    NASA Astrophysics Data System (ADS)

    Tali, Maris; Alía, Rubén García; Brugger, Markus; Ferlet-Cavrois, Veronique; Corsini, Roberto; Farabolini, Wilfrid; Mohammadzadeh, Ali; Santin, Giovanni; Virtanen, Ari

    2017-08-01

    We present experimental evidence of electron-induced upsets in a reference European Space Agency (ESA) single event upset (SEU) monitor, induced by a 200-MeV electron beam at the Very energetic Electronic facility for Space Planetary Exploration in harsh Radiation environments facility at CERN. Comparison of experimental cross sections and simulated cross sections is shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons, flash effects, and cumulative dose effects are discussed, showing that electronuclear reactions are the expected SEU mechanism. The ESA Jupiter Icy Moons Explorer mission, to be launched in 2022, presents a challenging radiation environment due to the intense high-energy electron flux in the trapped radiation belts. Insight is given to the possible contribution of electrons to the overall upset rates in the Jovian radiation environment. Relative contributions of both typical electron and proton spectra created when the environmental spectra are transported through a typical spacecraft shielding are shown and the different mission phases are discussed.

  12. In-Flight Observations of Long-Term Single Event Effect(SEE)Performance on Orbview-2 and Xray Timing Explorer(XTE)Solid State Recorders (SSR)

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Barth, Janet L.; LaBel, Ken A.; Gee, George; Safren, Harvey

    2003-01-01

    This paper presents Single Event Effect (SEE) in-flight data on Solid State Recorders (SSR) that have been collected over a long period of time for two NASA spacecraft: Orbview-2 and XTE. SEE flight data on solid-state memories give an opportunity to study the behavior in space of SEE sensitive commercial devices. The actual Single Event Upset (SEU) rates can be compared with the calculated rates based on environment models and ground test data. The SEE mitigation schemes can also be evaluated in actual implementation. A significant amount of data has already been published concerning observed SEE effects on memories in space. However, most of the data presented cover either a short period of time or a small number of devices. The data presented here has been collected on a large number of devices during several years. This allows statistically significant information about the effect of space weather fluctuations on SEU rates, and the effectiveness of SEE countermeasures used to be analyzed. Only Orbview-2 data is presented in this summary. XTE data will be included in the final paper.

  13. Space and military radiation effects in silicon-on-insulator devices

    SciTech Connect

    Schwank, J.R.

    1996-09-01

    Advantages in transient ionizing and single-event upset (SEU) radiation hardness of silicon-on-insulator (SOI) technology spurred much of its early development. Both of these advantages are a direct result of the reduced charge collection volume inherent to SOI technology. The fact that SOI transistor structures do not include parasitic n-p-n-p paths makes them immune to latchup. Even though considerable improvement in transient and single-event radiation hardness can be obtained by using SOI technology, there are some attributes of SOI devices and circuits that tend to limit their overall hardness. These attributes include the bipolar effect that can ultimately reduce the hardness of SOI ICs to SEU and transient ionizing radiation, and charge buildup in buried and sidewall oxides that can degrade the total-dose hardness of SOI devices. Nevertheless, high-performance SOI circuits can be fabricated that are hardened to both space and nuclear radiation environments, and radiation-hardened systems remain an active market for SOI devices. The effects of radiation on SOI MOS devices are reviewed.

  14. Results of radiation test of the cathode front-end board for CMS endcap muon chambers

    NASA Astrophysics Data System (ADS)

    Breedon, R.; Bylsma, B.; Durkin, L. S.; Gilmore, J.; Gu, J.; Hauser, J.; Holbrook, B.; Kim, C. L.; Ling, T. Y.; von der Mey, M.; Murray, P.; Rush, C. J.; Santiard, J. C.; Tripathi, M.

    2001-10-01

    After a brief overview of the CMS EMU electronics system, results on radiation induced single event effects, total ionization dose and displacement effects will be reported. These results are obtained by irradiating the components on electronics boards with 63 MeV protons and 1 MeV neutrons. During the proton irradiation, the electronics board was fully under power, all components on the board were active and the data were read out in the same way as designed for CMS. No deterioration of analog performance for each of the three CMOS ASICs on the tested board was observed, up to a dose of 10 krad. Each of the tested FPGAs survived beyond the dose of 30 krad. No single event latch-up was detected for the CMOS ASICs up to a proton fluence of 2×10 12 cm-2. Single Event Upsets (SEU) in FPGAs were detected and their cross-sections measured. SEU mitigation with triple module redundancy and voting was implemented and tested.

  15. Micro-Inspector Avionics Module (MAM): A Self-Contained Low Power, Reconfigurable Avionics Platform for Small Spacecrafts and Instruments

    NASA Technical Reports Server (NTRS)

    Ashtijou, Mohammad; He, Yutao; Watson, R. Kevin; Bolotin, Gary S.

    2006-01-01

    This paper describes development of a radiation tolerant, low power, reconfigurable avionics module aimed at meeting the avionics needs of the JPL Micro-Inspector spacecraft. This module represents a complete avionics system, consisting of two PowerPC 405 CPUs embedded within a reconfigurable FPGA fabric of over 8 Million logic gates, 64MB of EDAC protected Flash storage and 128MB of EDAC protected DDR SDRAM or SDRAM memories, along with FPGA SEU mitigation logic, and all necessary power conversion. Processor SEU mitigation is achieved by running the two processors in a lock-step and compare configuration. All of these building blocks are integrated into a double sided circuit board that takes as little as 6 square inches of board space. This module can be embedded into a user system as part of a bigger circuit assembly or as a self contained module. This module is being developed as part of a JPL led Micro-Inspector Program, funded by NASA ESMD aimed at producing a 10Kg micro spacecraft.

  16. A comparison of two different types of geosynchronous satellite measurements during the 1989 solar proton events.

    PubMed

    Normand, E

    1994-10-01

    The proton telescope aboard the GOES-7 satellite continuously records the proton flux at geosynchronous orbit, and therefore provides a direct measurement of the energetic protons arriving during solar energetic particle (SEP) events. Microelectronic devices are susceptible to single event upset (SEU) caused by both energetic protons and galactic cosmic ray (GCR) ions. Some devices are so sensitive that their upsets can be used as a dosimetric indicator of a high fluence of particles. The 93L422 1K SRAM is one such device. Eight of them are on the TDRS-1 satellite in geosynchronous orbit, and collectively they had been experiencing 1-2 upset/day due to the GCR background. During the large SEP events of 1989 the upset rate increased dramatically, up to about 250 for the week of 19 Oct, due to the arrival of the SEP protons. Using the GOES proton spectra, the proton-induced SEU cross section curve for the 93L422 and the shielding distribution around the 93L422, the calculated upsets based on the GOES satellite data compared well against the log of measured upsets on TDRS-1.

  17. Prevalence of staphylococcal enterotoxins, toxin genes and genetic-relatedness of foodborne Staphylococcus aureus strains isolated in the Marmara Region of Turkey.

    PubMed

    Aydin, Ali; Sudagidan, Mert; Muratoglu, Karlo

    2011-08-02

    Staphylococcus aureus is a major foodborne pathogen and it has the ability to produce a number of extracellular toxins. We analyzed 1070 food samples obtained from retail markets and dairy farms in the Marmara Region of Turkey for the presence of S. aureus. Out of 147 isolates, 92 (62.6%) were enterotoxigenic. PCR was used to investigate the presence of staphylococcal enterotoxin genes (sea, seb, sec, sed, see, seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq and seu), exfoliative toxin genes (eta and etb) and the toxic-shock syndrome toxin gene (tst). The PCR results showed that 53.3% of the isolates contained staphylococcal enterotoxin-like (SEl) toxin genes (seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq and seu) which were more frequent than classical enterotoxin genes (sea to see). Furthermore, seo, sei, sem, seg, seu and sec were found in 37.0, 32.7, 30.4, 29.3, 29.3 and 27.2% of the isolates, respectively. The tst gene was detected and confirmed by DNA sequencing in 9 isolates. The presence of eta and etb were not found in the isolates. Enterotoxigenic capabilities of isolates with SEA-SEE were investigated by ELISA. Enterotoxigenic S. aureus isolates produced one to three enterotoxins, with the most frequently produced types being enterotoxin A and C. There was a correlation of 72.1% between production of a specific toxin and the presence of the respective genes. PFGE analysis was used to identify genetic-relatedness of enterotoxigenic S. aureus isolates and the results revealed that 13 groups of isolates from different or the same origin that contained the same genes showed 100% homology with indistinguishable band patterns. The other enterotoxigenic isolates showed related band patterns with 72-86% homology in sea-, 61-90% homology in sec-, 80-96% homology in seh-, and 69-96% homology in sep-positive isolates. To our knowledge, this is the first study to examine enterotoxins and related gene contents of S. aureus food isolates in the Marmara

  18. Etiological agents and antimicrobial susceptibility in hospitalized children with acute pyelonephritis.

    PubMed

    Flor-de-Lima, Filipa; Martins, Tânia; Teixeira, Ana; Pinto, Helena; Botelho-Moniz, Edgar; Caldas-Afonso, Alberto

    2015-01-01

    Introdução: A resistência aos antimicrobianos, provocada pela utilização de antibióticos continua a ser um importante problema de saúde pública e uma preocupação para os profissionais de saúde. O nosso objetivo foi conhecer a prevalência local dos uropatógenos e o seu perfil de suscetibilidade aos antimicrobiannos na pielonefrite aguda. Material e Métodos: Estudo prospetivo nas crianças internadas por pielonefrite aguda no internamento de Pediatria de um hospital do norte de Portugal entre 1994-2012. Os agentes etiológicos e o seu perfil de sensibilidade aos antimicrobianos foram avaliados em quatro períodos de tempo (G1: 1994-1997, G2: 2002; G3: 2007; G4: 2012). Resultados: Avaliámos 581 doentes, 66% do sexo feminino, com idade mediana de 22 meses. A Escherichia coli foi o principal uropatógeno e a sua prevalência manteve-se estável durante os últimos 18 anos. Verificou-se um aumento da sensibilidade à amoxicilina/ácido clavulânico de 71% no G1 para 81,5% no G4 (p = 0,001) e uma diminuição da taxa de resistência de 8,7% no G1 para 2,8% G4 (p = 0,008). A sua sensibilidade às cefalosporinas de segunda e terceira geração e nitrofurantoína foi superior a 90% (p = ns). A taxa de resistência ao cotrimoxazol aumentou de 22 % para 26 % (p = 0,008). Discussão: A Escherichia coli continua a ser o uropatogénio mais frequente responsável por pielonefrite aguda, motivo pelo qual o seu perfil de sensibilidade aos antimicrobianos determina a escolha da antibioticoterapia empírica. Conclusões: A amoxicilina/ácido clavulânico mantém-se como escolha de primeira linha para o tratamento empírico da pielonefrite aguda em regime de internamento.

  19. [How xenon works: neuro and cardioprotection mechanisms].

    PubMed

    Morais, Ricardo; Andrade, Luísa; Lourenço, André; Tavares, Jorge

    2014-01-01

    Introdução: O xénon, um gás nobre, possui qualidades anestésicas, associadas a uma notável estabilidade hemodinâmica assim como propriedades cardioprotectoras e neuroprotectoras. As suas características físico-químicas conferem-lhe uma rápida indução e emergência anestésica, estando livre de efeitos deletérios importantes nos diversos orgãos e não apresentando teratogenicidade; o que suscitou um recente recrudescimento no interesse de aprofundar o conhecimento sobre este gás nobre, afim de compreender osseus mecanismos de acção e determinar as várias indicações que possui para a prática clínica.Material e Métodos: Revisão da literatura dos artigos considerados relevantes sobre o tema, com recurso à pesquisa de artigos indexados na Medline, com as palavras-chaves: xénon, xénon anestesia, xénon neuroproteção, xénon cardioproteção.Resultados: A aprovação do uso do xénon em doentes ASA I-II, ocorreu em Março 2007, após a realização de dois ensaios clínicos aleatorizados multicêntricos. No entanto, o seu uso na prática clínica, tem sido limitado pelo seu preço elevado. Parece pouco provável que as vantagens que oferece em relação aos restantes anestésicos justifique o seu uso em doentes ASA I-II. No entanto, poderá ser uma preciosa ajuda para a redução das co-morbilidades e mortalidade na anestesia de doentes ASA III-IV. As suas propriedades neuro e cardio-protectoras, são também alvo de intensa investigação, com resultados promissores.Discussão: Infelizmente, ainda não existem estudos de aleatorizados e multicêntricos que comprovem um perfil favorável do custobenefício do xénon em doentes ASA III-IV, em relação aos demais anestésicos.Conclusão: O lugar do xénon na Anestesiologia ainda se encontra por definir.

  20. Looking for the Perfect Mentor.

    PubMed

    Sá, Ana Pinheiro; Teixeira-Pinto, Cristina; Veríssimo, Rafaela; Vilas-Boas, Andreia; Firmino-Machado, João

    2015-01-01

    Introdução: A formação médica pós-graduada consiste num processo complexo no qual os orientadores assumem um papel fundamental. Apesar da sua importância, pouco se sabe sobre os orientadores dos internos portugueses. O presente estudo pretende caracterizar os orientadores de formação em Medicina Interna em Portugal. Material e Métodos: Realizado um estudo observacional, transversal e de carácter analítico, através um questionário online anónimo onde foram avaliadas as características demográficas dos orientadores, o seu percurso na Medicina Interna e envolvimento com o processo formativo. Resultados: Dos 213 questionários válidos (taxa de resposta estimada de 28,4%), a média global da satisfação com o orientador encontra-se nos 4,52 pontos (± 1,33), sendo a relação entre interno e orientador classificada nos 4,86 ± 1,04 pontos. O orientador âidealâfoi caracterizado como dedicado e responsável (4,9 ± 1,37 pontos), com domínio de competências práticas (4,8 ± 1,12 pontos) e teóricas (4,8 ± 1,07 pontos). Foram identificados como preditores da satisfação dos internos com o orientador a relação estabelecidaentre ambos, o envolvimento do orientador na formação, o seu dinamismo, inovação e disponibilidade [modelo explicativo de 82,5% da satisfação (R2 = 0,83; R2 a = 0,82)]. Discussão: O orientador desempenha um papel preponderante no sucesso da formação pós-graduada. Os internos de Medicina Interna em Portugal encontram-se globalmente satisfeitos com os seus orientadores e valorizam preferencialmente as suas capacidades pedagógicas. Conclusão: Este estudo aponta para a importância do orientador de formação na satisfação do interno com o seu internato, alertando para a necessidade de investir nos orientadores como forma de investimento na formação médica pós-graduada.

  1. Radiation Mitigation and Power Optimization Design Tools for Reconfigurable Hardware in Orbit

    NASA Technical Reports Server (NTRS)

    French, Matthew; Graham, Paul; Wirthlin, Michael; Wang, Li; Larchev, Gregory

    2005-01-01

    The Reconfigurable Hardware in Orbit (RHinO)project is focused on creating a set of design tools that facilitate and automate design techniques for reconfigurable computing in space, using SRAM-based field-programmable-gate-array (FPGA) technology. In the second year of the project, design tools that leverage an established FPGA design environment have been created to visualize and analyze an FPGA circuit for radiation weaknesses and power inefficiencies. For radiation, a single event Upset (SEU) emulator, persistence analysis tool, and a half-latch removal tool for Xilinx/Virtex-II devices have been created. Research is underway on a persistence mitigation tool and multiple bit upsets (MBU) studies. For power, synthesis level dynamic power visualization and analysis tools have been completed. Power optimization tools are under development and preliminary test results are positive.

  2. Technology for Elevated Temperature Tests of Structural Panels

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.

    1999-01-01

    A technique for full-field measurement of surface temperature and in-plane strain using a single grid imaging technique was demonstrated on a sample subjected to thermally-induced strain. The technique is based on digital imaging of a sample marked by an alternating line array of La2O2S:Eu(+3) thermographic phosphor and chromium illuminated by a UV lamp. Digital images of this array in unstrained and strained states were processed using a modified spin filter. Normal strain distribution was determined by combining unstrained and strained grid images using a single grid digital moire technique. Temperature distribution was determined by ratioing images of phosphor intensity at two wavelengths. Combined strain and temperature measurements demonstrated on the thermally heated sample were DELTA-epsilon = +/- 250 microepsilon and DELTA-T = +/- 5 K respectively with a spatial resolution of 0.8 mm.

  3. Uso de simulações na determinação de cores intrínsecas de estrelas no infravermelho

    NASA Astrophysics Data System (ADS)

    Rembold, S. B.; Ribeiro, D.; Ducati, J. R.; Bevilacqua, C.

    2003-08-01

    Apresentamos o método e alguns resultados preliminares da aplicação de simulações na determinação das cores intrínsecas de estrelas no infravermelho. A simulação consiste em gerar diagramas cor versus temperatura efetiva de estrelas sinteticas, para uma faixa de valores iniciais da cor intrínseca para cada tipo espectral. Os diagramas gerados sinteticamente são comparados com diagramas gerados a partir de observacoes e, com isso, extrai-se a cor intrínseca que melhor descreve as observações. Mostramos tabelas preliminares de cores intrínsecas e comparamos seu comportamento com determinações prévias e de outros autores.

  4. Creation of a Radiation Hard 0.13 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2010-08-01

    To support space applications we will develop an 0.13 micron CMOS library which should be radiation hard up to 200 krad. By introducing new radiation hard design rules we will minimize IC-level leakage and single event latchup (SEL). To reduce single event upset (SEU) we will add two p-MOS transistors to all flip flops. For reliability reasons we will use double contacts in all library elements. The additional rules and the library elements will then be integrated in our Cadence mixed signal designkit, Virtuoso IC6.1 [1]. A test chip will be produced with our in house 0.13 micron BiCMOS technology, see Ref. [2].Thereafter we will doing radiation tests according the ESA specifications, see Ref. [3], [4].

  5. Design of high performance and radiation hardened SPARC-V8 processor

    NASA Astrophysics Data System (ADS)

    Yuanfu, Zhao; Hui, Qin; Heping, Peng; Lixin, Yu

    2015-11-01

    Design of a highly reliable SPARC-V8 processor for space applications requires consideration single-event effects including single event upsets, single event transients, single event latch-up, as well as cumulative effects such as the total ionizing dose (TID). In this paper, the fault tolerance of the SPARC-V8 processor to radiation effects is discussed in detail. The SPARC-V8 processor, fabricated in the 65 nm CMOS process, achieves a frequency of 300 MHz with a core area of 9.78 × 9.78 mm2, and it is demonstrated that its radiation hardened performance is suitable for operating in a space environment through the key elements' experiments, which show TID resistance to 300 krad(Si), SEL immunity to greater than 92.5 MeV·cm2/mg, and an SEU error rate of 2.51 × 10-4 per day.

  6. Radiation Hard 0.13 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2013-08-01

    To support space applications we have developed an 0.13 micron CMOS library which should be radiation hard up to 200 krad. The article describes the concept to come to a radiation hard digital circuit and was introduces in 2010 [1]. By introducing new radiation hard design rules we will minimize IC-level leakage and single event latch-up (SEL). To reduce single event upset (SEU) we add two p-MOS transistors to all flip flops. For reliability reasons we use double contacts in all library elements. The additional rules and the library elements are integrated in our Cadence mixed signal design kit, “Virtuoso” IC6.1 [2]. A test chip is produced with our in house 0.13 micron BiCMOS technology, see Ref. [3]. As next step we will doing radiation tests according the european space agency (ESA) specifications, see Ref. [4], [5].

  7. [The Paduan doctor Alessandro Pellati, his library and the first edition of De medicorum astrologia].

    PubMed

    Fattori, D

    2008-01-01

    The article prints the text of a document in the Archivio di Stato, Venice, comprising a list of books intended for auction, with an estimate of their value. THey constitute the private library of Alessandro Pellati (d. 1487), a Paduan doctor about whom nothing is known, except his name appears in the colophon of the first edition of a short treatise attributed to Hippocrates, the De medicorum astrologia seu de esse aegrorum, translated into Latin and published in Padua in 1483. The considerable number of astrological works in his library show that Pellati was keenly interested in the subject which, under the title of "natural magic", had assumed a significant place in medical studies at that time, particularly in Padua.

  8. Analysis of CRRES PHA Data for Low-Energy-Deposition Events

    NASA Technical Reports Server (NTRS)

    McNulty, P. J.; Hardage, Donna

    2004-01-01

    This effort analyzed the low-energy deposition Pulse Height Analyzer (PHA) data from the Combined Release and Radiation Effects Satellite (CRRES). The high-energy deposition data had been previously analyzed and shown to be in agreement with spallation reactions predicted by the Clemson University Proton Interactions in Devices (CUPID) simulation model and existing environmental and orbit positioning models (AP-8 with USAF B-L coordinates). The scope of this project was to develop and improve the CUPID model by increasing its range to lower incident particle energies, and to expand the modeling to include contributions from elastic interactions. Before making changes, it was necessary to identify experimental data suitable for benchmarking the codes; then, the models to the CRRES PHA data could be applied. It was also planned to test the model against available low-energy proton or neutron SEU data obtained with mono-energetic beams.

  9. Heavy ion induced Single Event Phenomena (SEP) data for semiconductor devices from engineering testing

    NASA Technical Reports Server (NTRS)

    Nichols, Donald K.; Huebner, Mark A.; Price, William E.; Smith, L. S.; Coss, James R.

    1988-01-01

    The accumulation of JPL data on Single Event Phenomena (SEP), from 1979 to August 1986, is presented in full report format. It is expected that every two years a supplement report will be issued for the follow-on period. This data for 135 devices expands on the abbreviated test data presented as part of Refs. (1) and (3) by including figures of Single Event Upset (SEU) cross sections as a function of beam Linear Energy Transfer (LET) when available. It also includes some of the data complied in the JPL computer in RADATA and the SPACERAD data bank. This volume encompasses bipolar and MOS (CMOS and MHNOS) device data as two broad categories for both upsets (bit-flips) and latchup. It also includes comments on less well known phenomena, such as transient upsets and permanent damage modes.

  10. First results of the front-end ASIC for the strip detector of the PANDA MVD

    NASA Astrophysics Data System (ADS)

    Quagli, T.; Brinkmann, K.-T.; Calvo, D.; Di Pietro, V.; Lai, A.; Riccardi, A.; Ritman, J.; Rivetti, A.; Rolo, M. D.; Stockmanns, T.; Wheadon, R.; Zambanini, A.

    2017-03-01

    PANDA is a key experiment of the future FAIR facility and the Micro Vertex Detector (MVD) is the innermost part of its tracking system. PASTA (PAnda STrip ASIC) is the readout chip for the strip part of the MVD. The chip is designed to provide high resolution timestamp and charge information with the Time over Threshold (ToT) technique. Its architecture is based on Time to Digital Converters with analog interpolators, with a time bin width of 50 ps. The chip implements Single Event Upset (SEU) protection techniques for its digital parts. A first full-size prototype with 64 channels was produced in a commercial 110 nm CMOS technology and the first characterizations of the prototype were performed.

  11. Bench-level characterization of a CMOS standard-cell D-latch using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Blaes, B. R.; Soli, G. A.; Buehler, M. G.

    1991-01-01

    A methodology is described for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-micron n-well CMOS 4-kb test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 micron was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 MeV sq cm/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV sq cm/mg was determined.

  12. Silicon-on-insulator field effect transistor with improved body ties for rad-hard applications

    DOEpatents

    Schwank, James R.; Shaneyfelt, Marty R.; Draper, Bruce L.; Dodd, Paul E.

    2001-01-01

    A silicon-on-insulator (SOI) field-effect transistor (FET) and a method for making the same are disclosed. The SOI FET is characterized by a source which extends only partially (e.g. about half-way) through the active layer wherein the transistor is formed. Additionally, a minimal-area body tie contact is provided with a short-circuit electrical connection to the source for reducing floating body effects. The body tie contact improves the electrical characteristics of the transistor and also provides an improved single-event-upset (SEU) radiation hardness of the device for terrestrial and space applications. The SOI FET also provides an improvement in total-dose radiation hardness as compared to conventional SOI transistors fabricated without a specially prepared hardened buried oxide layer. Complementary n-channel and p-channel SOI FETs can be fabricated according to the present invention to form integrated circuits (ICs) for commercial and military applications.

  13. Single-event effects experienced by astronauts and microelectronic circuits flown in space

    SciTech Connect

    McNulty, P.J.

    1996-04-01

    Models developed for explaining the light flashes experienced by astronauts on Apollo and Skylab missions were used with slight modification to explain upsets observed in microelectronic circuits. Both phenomena can be explained by the simple assumption that an event occurs whenever a threshold number of ionizations or isomerizations are generated within a sensitive volume. Evidence is consistent with the threshold being sharp in both cases, but fluctuations in the physical stimuli lead to a gradual rather than sharp increase in cross section with LET. Successful use of the model requires knowledge of the dimensions of the sensitive volume and the value of threshold. Techniques have been developed to determine these SEU parameters in modern circuits.

  14. A feasibility study of a single event spectrometer based on semiconductor devices.

    PubMed

    Agosteo, S; Castoldi, A; Castellani, L; Colautti, P; D'Angelo, G; De Nardo, L; Favalli, A; Lippi, I; Martinelli, R; Tornielli, G; Zotto, P

    2002-01-01

    The electronics employed around particle accelerators can be disturbed or damaged because of single event effects (SEE). The most likely effect is the single event upset (SEU) which may affect all memory devices. In the case of high energy accelerators, SEUs are mostly produced by secondary charged particles generated by neutron interactions. The measurement of the energy and the lineal energy distribution of these neutron-induced charged particles was proposed. As a first approach, a commercial p-i-n photodiode was employed. This device was irradiated with thermal and monoenergetic fast neutrons. Some effects limiting the use of such a detector as a SEE spectrometer were observed, giving guidelines for the design of an application specific integrated circuit (ASIC). The possibility of creating a solid state microdosemeter by coupling the ASIC with a tissue-equivalent radiator is discussed. Moreover, the p-i-n photodiode covered with a hydrogenated plastic radiator may be employed as a proton-recoil spectrometer.

  15. Single Event Effects Test Results for the Actel ProASIC Plus and Altera Stratix-II Field Programmable Gate Arrays

    NASA Technical Reports Server (NTRS)

    Allen, Gregory R.; Swift, Gary M.

    2006-01-01

    This work describes radiation testing of Actel's ProASIC Plus and Altera's Stratix-II FPGAs. The Actel Device Under Test (DUT) was a ProASIC Plus APA300-PQ208 nonvolatile, field reprogrammable device which is based on a 0.22micron flash-based LVCMOS technology. Limited investigation has taken place into flash based FPGA technologies, therefore this test served as a preliminary reference point for various SEE behaviors. The Altera DUT was a Stratix-II EP2S60F1020C4. Single Event Upset (SEU) and Single Event Latchup (SEL) were the focus of these studies. For the Actel, a latchup test was done at an effective LET of 75.0 MeV-sq cm/mg at room temperature, and no latchup was detected when irradiated to a total fluence of 1 x 10(exp 7) particles/sq cm. The Altera part was shown to latchup at room temperature.

  16. Computational Algorithms for Device-Circuit Coupling

    SciTech Connect

    KEITER, ERIC R.; HUTCHINSON, SCOTT A.; HOEKSTRA, ROBERT J.; RANKIN, ERIC LAMONT; RUSSO, THOMAS V.; WATERS, LON J.

    2003-01-01

    Circuit simulation tools (e.g., SPICE) have become invaluable in the development and design of electronic circuits. Similarly, device-scale simulation tools (e.g., DaVinci) are commonly used in the design of individual semiconductor components. Some problems, such as single-event upset (SEU), require the fidelity of a mesh-based device simulator but are only meaningful when dynamically coupled with an external circuit. For such problems a mixed-level simulator is desirable, but the two types of simulation generally have different (sometimes conflicting) numerical requirements. To address these considerations, we have investigated variations of the two-level Newton algorithm, which preserves tight coupling between the circuit and the partial differential equations (PDE) device, while optimizing the numerics for both.

  17. Single event effects in static and dynamic registers in a 0.25{micro}m CMOS technology

    SciTech Connect

    Faccio, F.; Kloukinas, K.; Marchioro, A.; Calin, T.; Cosculluela, J.; Nicolaidis, M.; Velazco, R.

    1999-12-01

    The authors have studied Single Event Effects in static and dynamic registers designed in a quarter micron CMOS process. In the design, they systematically used guard rings and enclosed (edgeless) transistor geometry to improve the total dose tolerance. This design technique improved both the SEL and SEU sensitivity of the circuits. Using SPICE simulations, the measured smooth transition of the cross-section curve between LET threshold and saturation has been traced to the presence of four different upset modes, each corresponding to a different critical charge and sensitive area. A new architecture to protect the content of storage cells has been developed, and a threshold LET around 89 MeVcm{sup 2}mg{sup {minus}1} has been measured for this cell at a power supply voltage of 2 V.

  18. 2-Selenouridine triphosphate synthesis and Se-RNA transcription.

    PubMed

    Sun, Huiyan; Jiang, Sibo; Caton-Williams, Julianne; Liu, Hehua; Huang, Zhen

    2013-09-01

    2-Selenouridine ((Se)U) is one of the naturally occurring modifications of Se-tRNAs ((Se)U-RNA) at the wobble position of the anticodon loop. Its role in the RNA-RNA interaction, especially during the mRNA decoding, is elusive. To assist the research exploration, herein we report the enzymatic synthesis of the (Se)U-RNA via 2-selenouridine triphosphate ((Se)UTP) synthesis and RNA transcription. Moreover, we have demonstrated that the synthesized (Se)UTP is stable and recognizable by T7 RNA polymerase. Under the optimized conditions, the transcription yield of (Se)U-RNA can reach up to 85% of the corresponding native RNA. Furthermore, the transcribed (Se)U-hammerhead ribozyme has the similar activity as the corresponding native, which suggests usefulness of (Se)U-RNAs in function and structure studies of noncoding RNAs, including the Se-tRNAs.

  19. Radiation Hardened DDR2 SDRAM Solution

    NASA Astrophysics Data System (ADS)

    Wang, Pierre-Xiao; Sellier, Charles

    2016-08-01

    The Radiation Hardened (RH) DDR2 SDRAM Solution is a User's Friendly, Plug-and-Play and Radiation Hardened DDR2 solution, which includes the radiation tolerant stacking DDR2 modules and a radiation intelligent memory controller (RIMC) IP core. It provides a high speed radiation hardened by design DRAM solution suitable for all space applications such as commercial or scientific geo-stationary missions, earth observation, navigation, manned space vehicles and deep space scientific exploration. The DDR2 module has been guaranteed with SEL immune and TID > 100Krad(Si), on the other hand the RIMC IP core provides a full protection against the DDR2 radiation effects such as SEFI and SEU.

  20. NAND FLASH Radiation Tolerant Intelligent Memory Stack (RTIMS FLASH)

    NASA Astrophysics Data System (ADS)

    Sellier, Charles; Wang, Pierre

    2014-08-01

    The NAND Flash Radiation Tolerant and Intelligent Memory Stack (RTIMS FLASH) is a User's Friendly, Plug-and- Play and Radiation Protected high density NAND Flash Memory. It provides a very high density, radiation hardened by design and non-volatile memory module suitable for all space applications such as commercial or scientific geo-stationary missions, earth observation, navigation, manned space vehicles and deep space scientific exploration. The Intelligent Memory Module embeds a very high density of non-volatile NAND Flash memory and one Intelligent Flash Memory Controller (FMC). The FMC provides the module with a full protection against the radiation effects such as SEL, SEFI and SEU. It's also granting the module with bad block immunity as well as high level service functions that will benefit to the user's applications.

  1. Leonhard Euler and the mechanics of rigid bodies

    NASA Astrophysics Data System (ADS)

    Marquina, J. E.; Marquina, M. L.; Marquina, V.; Hernández-Gómez, J. J.

    2017-01-01

    In this work we present the original ideas and the construction of the rigid bodies theory realised by Leonhard Euler between 1738 and 1775. The number of treatises written by Euler on this subject is enormous, including the most notorious Scientia Navalis (1749), Decouverte d’un noveau principe de mecanique (1752), Du mouvement de rotation des corps solides autour d’un axe variable (1765), Theoria motus corporum solidorum seu rigidorum (1765) and Nova methodus motu corporum rigidorum determinandi (1776), in which he developed the ideas of the instantaneous rotation axis, the so-called Euler equations and angles, the components of what is now known as the inertia tensor, the principal axes of inertia, and, finally, the generalisation of the translation and rotation movement equations for any system. Euler, the man who ‘put most of mechanics into its modern form’ (Truesdell 1968 Essays in the History of Mechanics (Berlin: Springer) p 106).

  2. Summary of Proton Test on the Quick Logic QL3025 at Indiana University

    NASA Technical Reports Server (NTRS)

    Katz, Richard

    1998-01-01

    This issue of the Programmable Logic Application Notes is a compilation of topics: (1) Proton irradiation tests were performed on the Quick Logic QL3025 at the Indian University Cyclotron facility. The devices, tests, and results are discussed; (2) The functional failure of EEPROM's in heavy ion environment is presented; (3) the Act 1 architecture is summarized; (4) Antifuse hardness and hardness testing is updated; the single even upset (SEU) response of hardwired flip-flops is also presented; (4) Total dose results of the ACT 2 and ACT 3 circuits is presented in a chart; (5) Recent sub-micron devices testing of total dose is presented in a chart along with brief discussion; and (6) a reference to the WWW site for more articles of interest.

  3. Bench-level characterization of a CMOS standard-cell D-latch using alpha-particle sensitive test circuits

    NASA Technical Reports Server (NTRS)

    Blaes, B. R.; Soli, G. A.; Buehler, M. G.

    1991-01-01

    A methodology is described for predicting the SEU susceptibility of a standard-cell D-latch using an alpha-particle sensitive SRAM, SPICE critical charge simulation results, and alpha-particle interaction physics. Measurements were made on a 1.6-micron n-well CMOS 4-kb test SRAM irradiated with an Am-241 alpha-particle source. A collection depth of 6.09 micron was determined using these results and TRIM computer code. Using this collection depth and SPICE derived critical charge results on the latch design, an LET threshold of 34 MeV sq cm/mg was predicted. Heavy ion tests were then performed on the latch and an LET threshold of 41 MeV sq cm/mg was determined.

  4. Rare-earth phosphors for remote thermographic applications

    SciTech Connect

    Allison, S.W. ); Franks, L.A.; Borella, H.M.; Lutz, S.S.; Turley, W.D. ); Noel, B.W.; Beasley, A. )

    1989-04-01

    Numerous phosphors with rare-earth dopants have emissions that are strongly dependent on temperature and are therefore useful for remote-temperature measurement, especially in moving, confined, or hazardous systems. The emission properties of various phosphors of this type were measured from room temperature to {approximately}1,200{degree}C, along with data relative to their stability under thermal cycling. For practical temperature monitoring applications, thermographic phosphors must remain relatively stable under the conditions they must experience during the measurement. One important consideration then, is any change in fluorescent properties that might accompany temperature cycling. The phosphors that had the most stable behavior under cycling were La{sub 2}O{sub 2}S:Eu, YVO{sub 4}:Eu, Y{sub 2}O{sub 3}:Eu, and YVO{sub 4}:Dy. 7 refs., 11 figs., 1 tab.

  5. Single event upset sensitivity of low power Schottky devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Measel, P. R.; Wahlin, K. L.

    1982-01-01

    Data taken from tests involving heavy ions in the Berkeley 88 in. cyclotron being directed at low power Schottky barrier devices are reported. The tests also included trials in the Harvard cyclotron with 130 MeV protons, and at the U.C. Davis cyclotron using 56 MeV protons. The experiments were performed to study the single event upsets in MSI logic devices containing flip-flops. Results are presented of single-event upsets (SEU) causing functional degradation observed in post-exposure tests of six different devices. The effectiveness of the particles in producing SEUs in logic device functioning was found to be directly proportional to the proton energy. Shielding was determined to offer negligible protection from the particle bombardment. The results are considered significant for the design and fabrication of LS devices for space applications.

  6. The design and characterization of a prototype optical heat-flux gauge

    SciTech Connect

    Turley, W.D.; Borella, H.M.; Noel, B.W.; Beasley, A.; Sartory, W.K.; Cates, M.R.

    1989-01-01

    We have demonstrated the feasibility of using thermographic phosphors as the temperature sensors in an optical surface-heat-flux gauge. A heat flux of 40 kW/m/sup 2/ was measured with a gauge constructed by depositing La/sub 2/O/sub 2/S:Eu and Gd/sub 2/O/sub 2/S:Tb phosphors on the two faces of a polymethylpentene insulator. In the experiment, we measured a steady-state heat flux at a single point on a stationary surface; however, the gauge is also intended to measure transient heat flow. The technique is conceptually expandable to a two-dimensional temperature measurement. 17 refs., 10 figs., 1 tab.

  7. The ToPiX v4 prototype for the triggerless readout of the PANDA silicon pixel detector

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Calvo, D.; De Remigis, P.; Mignone, M.; Olave, J.; Rivetti, A.; Wheadon, R.; Zotti, L.

    2015-01-01

    ToPiX v4 is the prototype for the readout of the silicon pixel sensors for the Micro Vertex Detector of the PANDA experiment. ToPiX provides position, time and energy measurement of the incoming particles and is designed for the triggerless environment foreseen in PANDA. The prototype includes 640 pixels with a size of 100 × 100 μm2, a 160 MHz time stamp distribution circuit to measure both particle arrival time and released energy (via ToT technique) and the full control logic. The ASIC is designed in a 0.13 μm CMOS technology with SEU protection techniques for the digital parts.

  8. Primary expert system applied in design of electron-optical system

    NASA Astrophysics Data System (ADS)

    Lei, Wei; Tong, Linsu

    1995-09-01

    It is well known that the structure of electron optical system is complicated, so many factors, such as magnification, geometrical aberrations, and space charge effect must be taken into account in the design. At present, the main work of electron optical system CAD is solving equations and calculating numerical values. However, the designs perhaps need more inference and expertise than numerical calculations. In this paper, a primary expert system which is applied in design of electron optical system is established. This expert system is combined with the simulation software SEU-3D program to design some practical electron optical systems. Although the knowledge base is small and rules are not abundant, this paper has used this system to obtain some very useful results. The initial success with this system suggests that further work need to be done whether more rules and knowledge will be added to extend the ability of expert system.

  9. A Proposal for a Space Flight Demonstration of a Dynamically Reconfigurable Programmable Module Which Uses Firmware to Realise an Astrium Patented Cosmic Random Number Generator for Generating Secure Cryptographic Keys

    NASA Astrophysics Data System (ADS)

    Taylor, Adam; Bennie, Peter; Guyon, Fredric; Cameron, Iain; Glanfield, James; Emam, Omar

    2013-08-01

    This paper describes a proposal for a space flight demonstration of a low power, compact Dynamically Reconfigurable Programmable Board (DRPB) based upon a minor evolution of the Astrium Janus payload for UKube 1. The Janus payload is one of a number of the payloads selected to be part of the first national UK-Cube satellite (UKube) [1] to be sponsored by the UK Space Agency. In the UKube configuration the demonstrator performs two experiments the first uses firmware to realise an Astrium patented cosmic random number generator for generating secure cryptographic keys while the second monitors the large high performance SRAM based FPGA for SEU and SEFI events allowing correlation with predicted upset rates. This experiment is called the Janus experiment after the two-faced roman god of beginnings and transitions, transitioning from clear text to encrypted and marking the beginning of flying advanced FPGA's on suitable missions.

  10. Radiation-hard/high-speed array-based optical engine

    NASA Astrophysics Data System (ADS)

    Gan, K. K.; Buchholz, P.; Heidbrink, S.; Kagan, H. P.; Kass, R. D.; Moore, J.; Smith, D. S.; Vogt, M.; Ziolkowski, M.

    2016-12-01

    We have designed and fabricated a compact array-based optical engine for transmitting data at 10 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The DAC settings are stored in SEU (single event upset) tolerant registers. Several devices were irradiated with 24 GeV/c protons and the performance of the devices is satisfactory after the irradiation.

  11. The NASA Education Forum at SAO on the Structure and Evolution of the Universe

    NASA Technical Reports Server (NTRS)

    Gould, Roy; Cooper, Larry (Technical Monitor)

    2005-01-01

    The past year for the SEU Forum has been a highly productive one and has moved us forward on three major objectives: 1) Using the Einstein Centennial to involve the public in the Universe Exploration theme, with emphasis on exciting discoveries about dark energy, cosmology, and black holes; 2) Further implementing the recommendations of the Knappenberger Report, in order to strengthen the educational coherence of our collective activities and our collaborations within NASA; and 3) Developing strategic partnerships with underserved communities and other key customers. Among our activities for the past year are the following: 1) Serving the Informal Science Education Communities; 2) Serving the Formal Education (Pre-college) Community; and 3) Serving Minority and Underserved Communities. A summary of goals, plans and activities for the year 9/15/05 through 9/14/06 are also presented.

  12. Plastic optical fibre sensor for in-vivo radiation monitoring during brachytherapy

    NASA Astrophysics Data System (ADS)

    Woulfe, P.; Sullivan, F. J.; Lewis, E.; O'Keeffe, S.

    2015-09-01

    An optical fibre sensor is presented for applications in real-time in-vivo monitoring of the radiation dose a cancer patient receives during seed implantation in Brachytherapy. The sensor is based on radioluminescence whereby radiation sensitive scintillation material is embedded in the core of a 1mm plastic optical fibre. Three scintillation materials are investigated: thallium-doped caesium iodide (CsI:Tl), terbium-doped gadolinium oxysulphide (Gd2O2S:Tb) and europium-doped lanthanum oxysulphide (La2O2S:Eu). Terbium-doped gadolinium oxysulphide was identified as being the most suitable scintillator and further testing demonstrates its measureable response to different activities of Iodine-125, the radio-active source commonly used in Brachytherapy for treating prostate cancer.

  13. Charge generation by heavy ions in power MOSFETs, burnout space predictions, and dynamic SEB sensitivity

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Brucker, G. J.; Calvel, P.; Baiget, A.; Peyrotte, C.; Gaillard, R.

    1992-01-01

    The transport, energy loss, and charge production of heavy ions in the sensitive regions of IRF 150 power MOSFETs are described. The dependence and variation of transport parameters with ion type and energy relative to the requirements for single event burnout in this part type are discussed. Test data taken with this power MOSFET are used together with analyses by means of a computer code of the ion energy loss and charge production in the device to establish criteria for burnout and parameters for space predictions. These parameters are then used in an application to predict burnout rates in a geostationary orbit for power converters operating in a dynamic mode. Comparisons of rates for different geometries in simulating SEU (single event upset) sensitive volumes are presented.

  14. On Nibbles and Bytes: The Conundrum of Memory for Space Systems - NASA Electronic Parts and Packaging (NEPP) and Efforts in Memories

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Ladbury, Ray; Pellish, Jonathan; Sheldon, Douglas; Oldham, Timothy; Berg, Melanie D.; Cohn, Lewis M.

    2009-01-01

    Radiation requirements and trends. TID: 1) >90% of NASA applications are < 100 krads-Si in piecepart requirements. a) Many commercial devices (NVM and SDRAMs) meet or come close to this. b) Charge pump TID tolerance has improved an order magnitude over the last 10 years. 2) There are always a few programs with higher level needs and, of course, defense needs SEL: 1) Prefer none or rates that are considered low risk. a) Latent damage is a bear to deal with. 2) As we re packing cells tighter and even with lower Vdd, we re seeing SEL on commercial devices regularly (<90nm). a) Often in power conversion, I/O, or control areas. SEU: 1) It s not the bit errors, it s the SEFIs errors that are the biggest issues. a) Scrubbing concerns for risk, power, speed.

  15. Resources for Radiation Test Data

    NASA Technical Reports Server (NTRS)

    O'Bryan, Martha V.; Casey, Megan C.; Lauenstein, Jean-Marie; LaBel, Ken

    2016-01-01

    The performance of electronic devices in a space radiation environment is often limited by susceptibility to single-event effects (SEE), total ionizing dose (TID), and displacement damage (DD). Interpreting the results of SEE, TID, and DD testing of complex devices is quite difficult given the rapidly changing nature of both technology and the related radiation issues. Radiation testing is performed to establish the sensitivities of candidate spacecraft electronics to single-event upset (SEU), single-event latchup (SEL), single-event gate rupture (SEGR), single-event burnout (SEB), single-event transients (SETs), TID, and DD effects. Knowing where to search for these test results is a valuable resource for the aerospace engineer or spacecraft design engineer. This poster is intended to be a resource tool for finding radiation test data.

  16. [Nicolaus Steno's geometrical description of muscle: the investigation of muscle movements in the 17th century].

    PubMed

    Anzai, Natsume; Sawai, Tadashi; Sakai, Tatsuo

    2014-03-01

    Famous geologist Nicolaus Steno (1638-1686) was known as a skillful anatomist in his time. His main work about anatomy is "Elementorum myologiae specimen, seu musculi descriptio geometrica". Steno introduced geometrical representation into muscle study. His purpose was to handle muscle movements in the style of Cartesian mechanical philosophy, assuming muscle fibers as the structural and functional unit of muscle. Steno modelled muscles as parallelepiped integrations of fibers. Steno thought the shortening of muscle fibers modified parallelepiped integration and its modification resulted in muscle movements. His parallelepiped model enabled the regarding of muscles as objects of physics. Steno's assumption and model built a methodological foundation of mechanistic physiology of muscle, and influenced latter 17th century thinkers, especially Borelli.

  17. Benchmarking Ionizing Space Environment Models

    NASA Astrophysics Data System (ADS)

    Bourdarie, S.; Inguimbert, C.; Standarovski, D.; Vaillé, J.-R.; Sicard-Piet, A.; Falguere, D.; Ecoffet, R.; Poivey, C.; Lorfèvre, E.

    2017-08-01

    In-flight feedback data are collected, such as displacement damage doses, ionizing doses, and cumulated Single Event upset (SEU) on board various space vehicles and are compared to predictions performed with: 1) proton measurements performed with spectrometers data on board the same spacecraft if any and 2) protons spectrum predicted by the legacy AP8min model and the AP9 and Onera Proton Altitude Low models. When an accurate representation of the 3-D spacecraft shielding as well as appropriate ground calibrations are considered in the calculations, such comparisons provide powerful metrics to investigate engineering model accuracy. To describe >30 MeV trapped protons fluxes, the AP8 min model is found to provide closer predictions to observations than AP9 V1.30.001 (mean and perturbed mean).

  18. COST-EFFECTIVENESS OF PERIOPERATIVE IMMUNONUTRITION IN GASTROINTESTINAL ONCOLOGIC SURGERY: A SYSTEMATIC REVIEW.

    PubMed

    Reis, Audrey Machado Dos; Kabke, Geórgia Brum; Fruchtenicht, Ana Valéria Gonçalves; Barreiro, Taiane Dias; Moreira, Luis Fernando

    2016-01-01

    Costs, length of hospital staying and morbidity are frequently and significantly increased as a result of infections and other complications following surgical procedure for gastrointestinal tract cancer. Recently, improving host defence mechanisms have become a target of interest. Immunonutrition aims at improving immunity, most likely providing key nutrients to maintain T-lymphocyte and other host defence. To evaluate the immunonutrition in cancer patients who are operated by digestive diseases and assess the cost-effectiveness of this supplementation. This study consisted of a systematic review of the literature based on reference analyses retrieved from current databases such as PubMed, Lilacs and SciELO. The search strategy was defined by terms related to immunonutrition [immunonutrition, arginine, omega-3 and nucleotides] in combination with [costs, cost-effective and cost-effectiveness] as well as [gastrointestinal cancer surgery, oesophageal, gastric or pancreatic surgery] in English, Portuguese or Spanish language. For cost analyses, currencies used in the manuscripts were all converted to American dollars (US$) in order to uniform and facilitate comparison. Six prospective randomized studies were included in this review. The cost-effectiveness was positive in most of studies, demonstrating that this diet can significantly reduce hospital costs in the North hemisphere. However, similar studies needed to be carried to determine such results among us. Custos, tempo de hospitalização e morbidade estão frequentemente aumentados na presença de infecções e outras complicações decorrentes de procedimentos cirúrgicos para o câncer gastrointestinal. Recentemente, a melhora de mecanismos de defesa do hospedeiro tem se tornado um alvo de interesse. Nutrição adequada está fortemente relacionada com competência imune e redução de infeções. Imunonutrição objetiva a melhora da imunidade, principalmente para manutenção de linfócitos-T e outras

  19. Primary investigation the impacts of the external memory (DDR3) failures on the performance of Xilinx Zynq-7010 SoC based system (MicroZed) using laser irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Shuhuan; Du, Xuecheng; Du, Xiaozhi; Zhang, Yao; Mubashiru, Lawal Olarewaju; Luo, Dongyang; yuan, Yuan; Deng, Tianxiang; Li, Zhuoqi; Zang, Hang; Li, Yonghong; He, Chaohui; Ma, Yingqi; Shangguan, Shipeng

    2017-09-01

    The impacts of the external dynamic memory (DDR3) failures on the performance of 28 nm Xilinx Zynq-7010 SoC based system (MicroZed) were investigated with two sets of 1064 nm laser platforms. The failure sensitive area distributionsons on the back surface of the test DDR3 were primarily localized with a CW laser irradiation platform. During the CW laser scanning on the back surface of the DDR3 of the test board system, various failure modes except SEU and SEL (MBU, SEFI, data storage address error, rebooting, etc) were found in the testing embedded modules (ALU, PL, Register, Cache and DMA, etc) of SoC. Moreover, the experimental results demonstrated that there were 16 failure sensitive blocks symmetrically distributed on the back surface of the DDR3 with every sensitive block area measured was about 1 mm × 0.5 mm. The influence factors on the failure modes of the embedded modules were primarily analyzed and the SEE characteristics of DDR3 induced by the picoseconds pulsed laser were tested. The failure modes of DDR3 found were SEU, SEFI, SEL, test board rebooting by itself, unknown data, etc. Furthermore, the time interval distributions of failure occurrence in DDR3 changes with the pulsed laser irradiation energy and the CPU operating frequency were measured and compared. Meanwhile, the failure characteristics of DDR3 induced by pulsed laser irradiation were primarily explored. The measured results and the testing techniques designed in this paper provide some reference information for evaluating the reliability of the test system or other similar electronic system in harsh environment.

  20. The effect of fear-arousing communications on cigarette smoking: an expectancy-value approach.

    PubMed

    Sutton, S R; Eiser, J R

    1984-03-01

    This paper describes a model, derived from subjective expected utility ( SEU ) theory, which attempts to explain the effects of a fear-arousing communication about smoking and lung cancer on smokers' decisions to try to stop smoking. According to the model, the strength of the smoker's intention to try to stop smoking will depend on three factors: (1) the utility of lung cancer; (2) the perceived reduction in the risk of getting lung cancer that follows from successfully stopping smoking (probability difference); and (3) the subjective probability of successfully stopping smoking, or confidence. The usefulness of this model vis-á-vis one based on the amount of fear aroused by the communication was investigated in two experimental studies conducted in the field in which smokers watched either a videotape about smoking or one on a different health topic. The smoking videotape influenced not only attitudes and beliefs measured immediately after exposure but also subsequent self-reports of behavior (whether or not the subject tried to stop smoking or to cut down in the 3-month period following exposure to the videotape). In accordance with predictions, the three variables specified by the model together affected intention to try to stop smoking, which in turn affected behavior. The effect of confidence on intention was relatively large. There was no evidence for the multiplicative combination of utilities and subjective probabilities predicted by a strict SEU model. Contrary to the predictions of the model, but consistent with previous research, the amount of fear aroused by the videotape had an independent effect on intention, suggesting that explanations of the effects of fear-arousing communications will have to incorporate both cognitive and emotional mediation processes.

  1. [Determination of the contents of trace elements in chinese herbal medicines for treating respiratory system diseases].

    PubMed

    Han, Li-Qin; Dong, Shun-Fu; Liu, Jian-Hua

    2008-02-01

    There is an intimate connection between trace elements and body healthiness, trace elements and organism depend on each other, and each trace element exists with certain proportion, which preserve physio-function. If the balance is of maladjustment, diseases may occur or develop. The trace elements were determined in 16 kinds of Chinese herbal medicines by atomic absorption spectrometry. The medicines include lilium brownii, herba houttuyniae, licorice root, radices isatidis seu baphicacanthi, Sehizandra sinensis Bail, Scutellaria baicalensis Georgi, Beimu, Polygonum multiflorum Thunb, Lithospermum officinalel, Rhizoma acori gramjnoi, Pinellia ternate Breit, Salisburia adiantifolia, Lonicera japonica, Radices puerarire, Bupleurum falcatum and Ligusticum wallichii, all of which could be bought on the market. Sixteen kinds of Chinese herbal medicines commonly used to treat respiratroy system diseases in clinic were selected, dried and powdered, completely mixed, 1.000 0 g was weighed accurately with analytical balance, and 3 portions were used for each kind of sample. The atomic absorption spectrometry was used to determine the contents of trace elements (Cu, Zn, Fe, Cr, Ni and Mn), and the content discrepancy of the trace elements in different medicines was observed the results shows that the contents of the trace elements were rich in the 16 kinds of Chinese herbal medicines, there were more contents of Fe, Zn and Mn, but they were different in different medicines. And there were more trace elements in Salisburia adiantifolia, Polygonum multiflorum Thunb, Bupleurum falcatum, Sehizandra sinensis Bail, Pinellia ternate Breit and Lithospermum officinalel, and lower trace elements in Radices puerarire, Rhizoma acori gramjnoi and Radices isatidis seu baphicacanthi. The analytic results provided useful data for using Chinese herbal medicines and provided theoretical basis for studying Chinese herbal medicines theory.

  2. The Effectiveness of TAG or Guard-Gates in SET Suppression Using Delay and Dual-Rail Configurations at 0.35 microns

    NASA Technical Reports Server (NTRS)

    Shuler, Robert L.; Balasubramanian, Anupama; Narasimham, Balaji; Bhuva, Bharat; O'Neill, Patrick M.; Kouba, Coy

    2006-01-01

    Design options for decreasing the susceptibility of integrated circuits to Single Event Upset (SEU) fall into two categories: (1) increasing the critical charge to cause an upset at a particular node, and (2) employing redundancy to mask or correct errors. With decreasing device sizes on an Integrated Circuit (IC), the amount of charge required to represent a logic state has steadily reduced. Critical charge methods such as increasing drive strength or increasing the time required to change state as in capacitive or resistive hardening or delay based approaches extract a steadily increasing penalty as a percentage of device resources and performance. Dual redundancy is commonly assumed only to provide error detection with Triple Modular Redundancy (TMR) required for correction, but less well known methods employ dual redundancy to achieve full error correction by voting two inputs with a prior state to resolve ambiguity. This requires special circuits such as the Whitaker latch [1], or the guard-gate [2] which some of us have called a Transition AND Gate (TAG) [3]. A 2-input guard gate is shown in Figure 1. It is similar to a Muller Completion Element [4] and relies on capacitance at node "out" to retain the prior state when inputs disagree, while eliminating any output buffer which would be susceptible to radiation strikes. This paper experimentally compares delay based and dual rail flip-flop designs wherein both types of circuits employ guard-gates to optimize layout and performance, and draws conclusions about design criteria and suitability of each option. In both cases a design goal is protection against Single Event Transients (SET) in combinational logic as well as SEU in the storage elements. For the delay based design, it is also a goal to allow asynchronous clear or preset inputs on the storage elements, which are often not available in radiation tolerant designs.

  3. An Evolutionary Framework for Carpel Developmental Control Genes.

    PubMed

    Pfannebecker, Kai C; Lange, Matthias; Rupp, Oliver; Becker, Annette

    2017-02-01

    Carpels are the female reproductive organs of flowering plants (angiosperms), enclose the ovules, and develop into fruits. The presence of carpels unites angiosperms, and they are suggested to be the most important autapomorphy of the angiosperms, e.g., they prevent inbreeding and allow efficient seed dispersal. Many transcriptional regulators and coregulators essential for carpel development are encoded by diverse gene families and well characterized in Arabidopsis thaliana. Among these regulators are AGAMOUS (AG), ETTIN (ETT), LEUNIG (LUG), SEUSS (SEU), SHORT INTERNODE/STYLISH (SHI/STY), and SEPALLATA1, 2, 3, 4 (SEP1, 2, 3, 4). However, the timing of the origin and their subsequent molecular evolution of these carpel developmental regulators are largely unknown. Here, we have sampled homologs of these carpel developmental regulators from the sequenced genomes of a wide taxonomic sampling of the land plants, such as Physcomitrella patens, Selaginella moellendorfii, Picea abies, and several angiosperms. Careful phylogenetic analyses were carried out that provide a phylogenetic background for the different gene families and provide minimal estimates for the ages of these developmental regulators. Our analyses and published work show that LUG-, SEU-, and SHI/STY-like genes were already present in the Most Recent Common Ancestor (MRCA) of all land plants, AG- and SEP-like genes were present in the MRCA of seed plants and their origin may coincide with the ξ Whole Genome Duplication. Our work shows that the carpel development regulatory network was, in part, recruited from preexisting network components that were present in the MRCA of angiosperms and modified to regulate gynoecium development. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Brachial plexus morphology and vascular supply in the wistar rat.

    PubMed

    Angélica-Almeida, Maria; Casal, Diogo; Mafra, Manuela; Mascarenhas-Lemos, Luís; Martins-Ferreira, José; Ferraz-Oliveira, Mário; Amarante, José; Goyri-O'Neill, João

    2013-01-01

    Introdução: O rato é provavelmente a espécie animal mais utilizada em estudos experimentais de reparação nervosa. Com este trabalho pretendeu-se aprofundar o conhecimento da morfologia e da vascularização do plexo braquial do rato.Material e Métodos: Trinta ratos adultos foram estudados relativamente à morfologia e vascularização do plexo braquial. As técnicas usadas foram a injecção intravascular e dissecção sob microscópio operatório, bem como técnicas de microscopia óptica e microscopia electrónica de varrimento.Resultados: Morfologicamente, o plexo braquial do rato é um pouco diferente do plexo braquial humano. O suprimento arterial e venoso do plexo braquial do rato deriva direta ou indiretamente dos vasos vizinhos. Estes vasos formam plexos vasculares densos e interconectados no epinervo, perinervo e endonervo. Vários componentes do plexo braquial do rato são acompanhados durante um trajecto relativamente longo por vasos sanguíneos relativamente calibrosos e constantes que fornecem o seu plexo epineural, tornando o seu levantamento como retalhos nervosos possível.Discussão: A vascularização do plexo braquial do rato não é muito diferente da reportada na espécie humana, tornando o rato um modelo animal útil para o estudo experimental da fisiopatologia e tratamento da patologia do nervo periférico.Conclusão: Os nossos resultados apoiam a homologia entre o rato e o Homem em termos de morfologia e vascularização do plexo braquial. Este trabalho sugere que vários componentes do plexo braquial do rato podem ser utilizados como retalhos nervosos, incluindo fibras predominantemente motoras, sensitivas ou fibras mistas.

  5. Inguinodynia in patients submitted to conventional inguinal hernioplasty.

    PubMed

    Dias, Bruno Garcia; Santos, Marcelo Protásio Dos; Chaves, Ana Barbara DE Jesus; Willis, Mariana; Gomes, Marcio Couto; Andrade, Fernandes Tavares; Melo, Valdinaldo Aragão DE; Santos, Paulo Vicente Dos

    2017-01-01

    to evaluate the incidence of chronic pain and its impact on the quality of life of patients submitted to inguinal hernioplasty using the Lichtenstein technique. this was a descriptive, cross-sectional study of patients operated under spinal anesthesia from February 2013 to February 2015 and who had already completed six postoperative months. We questioned patients about the presence of chronic inguinal pain and, if confirmed, invited them to a consultation in which we assessed the pain and its impact on quality of life. out of 158 patients submitted to the procedure, we identified 7.6% as having inguinodynia. Of these, there was an impact on the quality of life in 25%. the incidence of inguinodynia after hernioplasty with repercussion in quality of life was similar to the one of found in the world literature. avaliar a incidência de dor crônica e o seu impacto na qualidade de vida de pacientes submetidos à hernioplastia inguinal pela técnica de Lichtenstein. trata-se de estudo transversal descritivo, de pacientes operados de hérnia inguinal pela técnica de Lichtenstein sob anestesia raquidiana, no período de fevereiro de 2013 a fevereiro de 2015, e que já haviam completado seis meses de pós-operatório. Os pacientes foram questionados sobre a presença de dor inguinal crônica e, caso confirmada, convidados a uma consulta na qual foi feita análise da qualidade da dor e seu impacto na qualidade de vida. do total de 158 pacientes submetidos ao procedimento, 7,6% foram identificados como portadores de inguinodinia. Destes, houve impacto na qualidade de vida em 25%. observou-se incidência de inguinodinia pós-hernioplastia com repercussão na qualidade de vida semelhante à literatura mundial.

  6. Diode and phosphor soft x-ray detectors: Studies of surface recombination, damage, and intensity effects in conversion efficiencies

    SciTech Connect

    Husk, D.E.

    1992-01-01

    The author has measured the linearity of ZnS:Ag and Y[sub 2]O[sub 2]S:Eu over some 9 orders of magnitude of intensity. The photons-out per photon-in, [open quote]absolute quantum efficiency[close quote], of Y[sub 2]O[sub 2]S:Eu was found to be linear over this range while the expected nonlinearity of ZnS:Ag was measured in terms of absolute flux. The absolute quantum efficiency of 4 photodiodes was measured in the soft x-ray regime. The structure in the efficiency vs energy curves for the diodes was explained through the use of a model that involves carrier diffusion length, thickness of the surface layer, bulk gain of the diode, reflection coefficient and surface recombination velocity. The stability of the diodes of soft x-ray flux was also measured. Further he has measured the quantum efficiency of sodium salicylate from 70 to 280 eV. He has been able to fit a model to this efficiency using carrier diffusion length, bulk gain of the diode, the reflection coefficient and surface recombination velocity. By extending this model to low energies the author has explained the different shapes of the efficiency curves reported in the literature as being due to different surface recombination velocities. He has also explained the low energy [open quote]damage[close quote] reported in the literature as being due to changing surface recombination velocity. In addition, he has measured a change in the bulk quantum efficiency that involves second-order kinetics of the incident flux. Finally the author also measured the absolute quantum efficiency of 16 phosphors over the range from [approximately]20 to 500 eV. The stability as a function of intensity over various ranges has also been measured.

  7. Study on Radiation Condition in DAMPE Orbit by Analyzing the Engineering Data of BGO Calorimeter

    NASA Astrophysics Data System (ADS)

    Feng, Changqing; Liu, Shubin; Zhang, Yunlong; Ma, Siyuan

    2016-07-01

    The DAMPE (DArk Matter Particle Explorer) is a scientific satellite which was successfully launched into a 500 Km sun-synchronous orbit, on December 17th, 2015, from the Jiuquan Satellite Launch Center of China. The major scientific objectives of the DAMPE mission are primary cosmic ray, gamma ray astronomy and dark matter particles, by observing high energy primary cosmic rays, especially positrons/electrons and gamma rays with an energy range from 5 GeV to 10 TeV. The BGO calorimeter is a critical sub-detector of DAMPE payload, for measuring the energy of cosmic particles, distinguishing positrons/electrons and gamma rays from hadron background, and providing trigger information. It utilizes 308 BGO (Bismuth Germanate Oxide) crystal logs with the size of 2.5cm*2.5cm*60cm for each log, to form a total absorption electromagnetic calorimeter. All the BGO logs are stacked in 14 layers, with each layer consisting of 22 BGO crystal logs and each log is viewed by two Hamamatsu R5610A PMTs (photomultiplier tubes), from both sides respectively. In order to achieve a large dynamic range, each PMT base incorporates a three dynode (2, 5, 8) pick off, which results in 616 PMTs and 1848 signal channels. The readout electronics system, which consists of 16 FEE (Front End Electronics) modules, was developed. Its main functions are based on the Flash-based FPGA (Field Programmable Gate Array) chip and low power, 32-channel VA160 and VATA160 ASICs (Application Specific Integrated Circuits) for precisely measuring the charge of PMT signals and providing "hit" signals as well. The hit signals are sent to the trigger module of PDPU (Payload Data Process Unit) and the hit rates of each layer is real-timely recorded by counters and packed into the engineering data, which directly reflect the flux of particles which fly into or pass through the detectors. In order to mitigate the SEU (Single Event Upset) effect in radioactive space environment, certain protecting methods, such as TMR

  8. Early geomorphological evolution of the North Polar Layered Deposits, Mars, from SHARAD radar-facies mapping

    NASA Astrophysics Data System (ADS)

    Nerozzi, Stefano; Holt, John W.

    2014-05-01

    The north polar layered deposits (NPLD) are the largest accumulation of water ice in the northern hemisphere of Mars. Since their discovery, they are thought to hold a valuable record of recent climate change within their stratigraphy (Murray et al., Icarus, 1972; Cutts, JGR, 1973b), yet little is known about their age and accumulation history. Due to exposures in trough walls, detailed stratigraphy of the uppermost layers and their evolution have been studied extensively since the first Mariner 9 images of the NPLD (e.g. Soderblom et al., JGR, 1973). However, large portions of the polar cap are still unmapped and no detailed studies of the lowermost layered deposits have been performed to date, primarily due to a general lack of visible exposures. Correlation of reflectors within radargrams acquired by the Shallow Radar (SHARAD) (Seu et al., Planet. Space Sci., 2004) onboard Mars Reconnaissance Orbiter makes a detailed stratigraphic reconstruction of the NPLD possible. An extensive set of radargrams is available over Planum Boreum and individual reflectors can be traced over hundreds of kilometers (Seu et al., JGR, 2007a; Putzig et al., Icarus, 2009; Holt et al., Nature, 2010) with a theoretical vertical resolution of ~9 m in water ice (Seu et al., JGR, 2007a). In this study, we present a highly-detailed stratigraphic reconstruction of the first ~500 m of the NPLD at a scale down to the single reflector. A set of 8 horizons was tracked across 700+ radargrams, and thicknesses were calculated for each stratigraphic interval assuming a bulk composition of water ice. Along with the quantitative analysis of derived isopach maps, this study is based on the qualitative comparison of "radar facies" in different locations of Planum Boreum with techniques borrowed from traditional sequence stratigraphy. In general, the NPLD is characterized by uniform layering. However, important layer extent and thickness variations are observed within the lowermost sequence. Limited

  9. New On-board Microprocessors

    NASA Astrophysics Data System (ADS)

    Weigand, R.

    Two new processor devices have been developed for the use on board of spacecrafts. An 8-bit 8032-microcontroller targets typical controlling applications in instruments and sub-systems, or could be used as a main processor on small satellites, whereas the LEON 32-bit SPARC processor can be used for high performance controlling and data processing tasks. The ADV80S32 is fully compliant to the Intel 80x1 architecture and instruction set, extended by additional peripherals, 512 bytes on-chip RAM and a bootstrap PROM, which allows downloading the application software using the CCSDS PacketWire pro- tocol. The memory controller provides a de-multiplexed address/data bus, and allows to access up to 16 MB data and 8 MB program RAM. The peripherals have been de- signed for the specific needs of a spacecraft, such as serial interfaces compatible to RS232, PacketWire and TTC-B-01, counters/timers for extended duration and a CRC calculation unit accelerating the CCSDS TM/TC protocol. The 0.5 um Atmel manu- facturing technology (MG2RT) provides latch-up and total dose immunity; SEU fault immunity is implemented by using SEU hardened Flip-Flops and EDAC protection of internal and external memories. The maximum clock frequency of 20 MHz allows a processing power of 3 MIPS. Engineering samples are available. For SW develop- ment, various SW packages for the 8051 architecture are on the market. The LEON processor implements a 32-bit SPARC V8 architecture, including all the multiply and divide instructions, complemented by a floating-point unit (FPU). It includes several standard peripherals, such as timers/watchdog, interrupt controller, UARTs, parallel I/Os and a memory controller, allowing to use 8, 16 and 32 bit PROM, SRAM or memory mapped I/O. With on-chip separate instruction and data caches, almost one instruction per clock cycle can be reached in some applications. A 33-MHz 32-bit PCI master/target interface and a PCI arbiter allow operating the device in a plug-in card

  10. Cosmic Journeys. To the Edge of Gravity, Space and Time: Structure and Evolution of the Universe Roadmap: 2003-2023

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Roadmap for the Structure and Evolution of the Universe (SEU) Theme embraces three fundamental, scientific quests: (1) To explain structure in the Universe and forecast our cosmic destiny, (2) To explore the cycles of matter and energy in the evolving Universe, (3) To examine the ultimate limits of gravity and energy in the Universe. We develop these quests into six focused research campaigns: (1) Identify dark matter and learn how it shapes galaxies and systems of galaxies, (2) Explore where and when the chemical elements were made (3) Understand the cycles in which matter, energy, and magnetic field are exchanged between stars and the gas between stars, (4) Discover how gas flows in disks and how cosmic jets are formed, (5) Identify the sources of gamma-ray bursts and high-energy cosmic rays, (6) Measure how strong gravity operates near black holes and how it affects the early Universe. These campaigns lead to a portfolio of future major missions of great scientific interest and popular appeal, strongly endorsed by the scientific community. Many have undergone significant initial study. Some are in a state of readiness that make them ideal candidates for the present Office of Space Science Strategic Plan; others may well feature in the next Plan. Each provides a golden scientific opportunity to advance our understanding of the Universe. We have identified three top-priority near-term science objectives together with missions to accomplish these goals. The three problems span a diverse range of subdisciplines, of observational technique, of timescales, and of cost, and are thus complementary, forming a coherent core program for the SEU theme in the 2003-2007 timeframe.These are : (1) Obtain precise measures of the chemical composition and physical conditions in objects ranging from the closest stars to the most distant quasars, (2) Utilize gravitational radiation as a probe of supermassive blackholes throughout the universe, (3) determine the nature of the

  11. The Single Event Effect Characteristics of the 486-DX4 Microprocessor

    NASA Technical Reports Server (NTRS)

    Kouba, Coy; Choi, Gwan

    1996-01-01

    This research describes the development of an experimental radiation testing environment to investigate the single event effect (SEE) susceptibility of the 486-DX4 microprocessor. SEE effects are caused by radiation particles that disrupt the logic state of an operating semiconductor, and include single event upsets (SEU) and single event latchup (SEL). The relevance of this work can be applied directly to digital devices that are used in spaceflight computer systems. The 486-DX4 is a powerful commercial microprocessor that is currently under consideration for use in several spaceflight systems. As part of its selection process, it must be rigorously tested to determine its overall reliability in the space environment, including its radiation susceptibility. The goal of this research is to experimentally test and characterize the single event effects of the 486-DX4 microprocessor using a cyclotron facility as the fault-injection source. The test philosophy is to focus on the "operational susceptibility," by executing real software and monitoring for errors while the device is under irradiation. This research encompasses both experimental and analytical techniques, and yields a characterization of the 486-DX4's behavior for different operating modes. Additionally, the test methodology can accommodate a wide range of digital devices, such as microprocessors, microcontrollers, ASICS, and memory modules, for future testing. The goals were achieved by testing with three heavy-ion species to provide different linear energy transfer rates, and a total of six microprocessor parts were tested from two different vendors. A consistent set of error modes were identified that indicate the manner in which the errors were detected in the processor. The upset cross-section curves were calculated for each error mode, and the SEU threshold and saturation levels were identified for each processor. Results show a distinct difference in the upset rate for different configurations of

  12. On-orbit performance of TOPEX/POSIEDON star trackers

    NASA Astrophysics Data System (ADS)

    Kia, Tooraj; Hanover, Gene A.

    1996-10-01

    The primary objective of the TOPEX/POSIEDON satellite is to monitor the world's oceans for scientific study of ocean circulation leading to weather and climate prediction, coastal storm warning and maritime safety. TOPEX/POSIEDON was launched on August 10, 1992 from the Kourou Space Center in French Guyana on a nominal circular orbit with an altitude of 1336 Km with a 66 degree inclination. Selection of this orbit imposed challenging requirements on the on- board electronics. At this altitude, South Atlantic Anomaly (SAA) covers a large area. During many orbits the satellite may spend up to 40 minutes in the SAA region, all the time being bombarded by heavy protons and other charged particles. The on-board electronics were required to endure an estimated total dose radiation of 70 KRAD, with an RDM of 2, over the prime mission life of three years. In addition to the total dose radiation requirement, the spacecraft is required to perform within specifications in-spite of the heavy protons present at this orbit. TOPEX/POSIEDON is the first NASA satellite to carry two CCD based star trackers on a long duration mission. TOPEX/POSIEDON star trackers, known as advanced star tracker (ASTRA), were designed and built by Hughes Danbury Optical Systems (HDOS). These trackers have experienced single-event upsets and possible radiation induced radiation changes in their characteristics. One of the trackers has been in an in-operable state since being hit by a suspected SEU in November 1992. The second tracker has also had anomalies indicative of an SEU, but has managed to recover and is performing within the TOPEX specifications. JPL has been monitoring and evaluating the performance of these star trackers, during the last forty months. The data show change in certain tracker characteristics such as the magnitude of the detected stars, the background counts and the hot pixel data. This paper addresses the CCD tracker performance and the change in their characteristics in the

  13. Path of infectious diseases in Brazil in the last 50 years: an ongoing challenge.

    PubMed

    Waldman, Eliseu Alves; Sato, Ana Paula Sayuri

    2016-12-22

    In this article, we comment on the main features of infectious diseases in Brazil in the last 50 years, highlighting how much of this path Revista de Saúde Pública could portray. From 1967 to 2016, 1,335 articles focusing on infectious diseases were published in Revista de Saúde Pública. Although the proportion of articles on the topic have decreased from about 50.0% to 15.0%, its notability remained and reflected the growing complexity of the research required for its control. It is noteworthy that studies design and analysis strategies progressively became more sophisticated, following the great development of epidemiology in Brazil in the recent decades. Thus, the journal has followed the success of public health interventions that permitted to control or eliminate numerous infectious diseases - which were responsible, in the past, for high rates of morbidity and mortality -, and also followed the reemergence of diseases already controlled and the emergence of until then unknown diseases, with a strong impact on the Brazilian population, establishing a little predictable and very challenging path. RESUMO Neste artigo, comentamos as principais características das doenças infecciosas no Brasil, nos últimos 50 anos, destacando o quanto a Revista de Saúde Pública conseguiu capturar essa trajetória. De 1967 a 2016, foram publicados 1.335 artigos na Revista de Saúde Pública com foco em doenças infecciosas. Ainda que a proporção de artigos sobre esse tema tenha declinado de cerca de 50,0% para 15,0%, seu destaque se manteve e refletiu a crescente complexidade das pesquisas necessárias para o seu controle. Nota-se que os desenhos dos estudos e as estratégias de análise ganharam progressivamente maior sofisticação, acompanhando o grande desenvolvimento da epidemiologia no Brasil, nas últimas décadas. Assim, foi registrado não apenas o sucesso de intervenções de saúde pública que permitiram o controle ou a eliminação de inúmeras doen

  14. Perception of nursing faculty on the care: Heidegger constructions.

    PubMed

    Sebold, Luciara Fabiane; Kempfer, Silvana Silveira; Girondi, Juliana Balbinot Reis; Prado, Marta Lenise

    2016-06-01

    To understand the perceptions of nursing teachers about care in the light of Heidegger's framework. It was used as theoretical and methodological reference Hei- degger's hermeneutics. To capture the meanings we used phenomenological interviews with 11 teachers. e data analysis is based on heideggerian hermeneutic. The way to be a nurse determines their way of life to the care that re ects the construction of experiences in the nursing worldliness. The existence of the nurse for nursing care is evidenced in care relations established between being careful and being caregiver, deciding the mode of being-there of the nurse who has before him and on the other the possibilities of care. It is being in the world that the being-nurse is manifested in their subjectivity in care for sensitive, is the objectivity of scienti c care, and is in the interrelationship with being careful is that manifests the being of choices and existing decisions in his way of being. Compreender as percepções dos docentes de enfermagem sobre o cuidado à luz do referencial de Heidegger. Utilizou-se como referencial teórico-metodológico hermenêutica heideggeriana. Para captar os significados utilizou-se entrevista fenomenológica realizada com 11 docentes. A análise dos dados baseou-se na hermenêutica heideggeriana. O modo de ser enfermeiro determina seu modo de ser para o cuidado, que é reflexo da construção das experiências na mundaneidade da enfermagem. A existência do ser enfermeiro para o cuidado de enfermagem é evidenciado nas relações de cuidado estabelecidas entre o ser cuidado e o ser cuidador, decidindo o modo de ser-aí do enfermeiro que tem diante de si e do outro as possibilidades de cuidado. É ser-no-mundo que o ser-enfermeiro se manifesta, em sua subjetividade no cuidar sensível, é na objetividade do cuidar científico, e é na inter-relação com o ser cuidado é que manifesta o ser de escolhas e decisões existindo em seu modo de ser.

  15. Cosmic Journeys. To the Edge of Gravity, Space and Time: Structure and Evolution of the Universe Roadmap: 2003-2023

    NASA Astrophysics Data System (ADS)

    1999-09-01

    The Roadmap for the Structure and Evolution of the Universe (SEU) Theme embraces three fundamental, scientific quests: (1) To explain structure in the Universe and forecast our cosmic destiny, (2) To explore the cycles of matter and energy in the evolving Universe, (3) To examine the ultimate limits of gravity and energy in the Universe. We develop these quests into six focused research campaigns: (1) Identify dark matter and learn how it shapes galaxies and systems of galaxies, (2) Explore where and when the chemical elements were made (3) Understand the cycles in which matter, energy, and magnetic field are exchanged between stars and the gas between stars, (4) Discover how gas flows in disks and how cosmic jets are formed, (5) Identify the sources of gamma-ray bursts and high-energy cosmic rays, (6) Measure how strong gravity operates near black holes and how it affects the early Universe. These campaigns lead to a portfolio of future major missions of great scientific interest and popular appeal, strongly endorsed by the scientific community. Many have undergone significant initial study. Some are in a state of readiness that make them ideal candidates for the present Office of Space Science Strategic Plan; others may well feature in the next Plan. Each provides a golden scientific opportunity to advance our understanding of the Universe. We have identified three top-priority near-term science objectives together with missions to accomplish these goals. The three problems span a diverse range of subdisciplines, of observational technique, of timescales, and of cost, and are thus complementary, forming a coherent core program for the SEU theme in the 2003-2007 timeframe.These are : (1) Obtain precise measures of the chemical composition and physical conditions in objects ranging from the closest stars to the most distant quasars, (2) Utilize gravitational radiation as a probe of supermassive blackholes throughout the universe, (3) determine the nature of the

  16. The Teaching of Astronomy in Uruguay. (Spanish Title: La Enseñanza de la Astronomía en Uruguay.) O Ensino da Astronomia no Uruguai

    NASA Astrophysics Data System (ADS)

    Pintos Ganón, Reina; Fernández, Julio Angel

    2008-07-01

    We present in this work the development of astronomy in Uruguay since the colony times up to the present, stressing in particular those aspects related to the formal as well as informal teaching of astronomy. The first antecedents of astronomical studies in our country go back to the beginnings of the XVIIIth century related to the scientific expeditions from Europe coming to our shores. The teaching of astronomy was generalized at the high school level as soon as the end of the XIXth century, while itsintroduction at the university level happened much later, around the middle of the last century. We analyze the current situation of this subject, its problems, and some measures to strengthen its development. Se presenta en este trabajo el desarrollo de la astronomía en el Uruguay desde la época colonial hasta el presente, destacando en particular los aspectos vinculados a su enseñanza tanto formal como informal. Los primeros antecedentes de estudios astronómicos datan de la época colonial relacionados con las expediciones científicas del Viejo Mundo que llegaban a nuestras costas. La enseñanza de la Astronomía se generalizó en el ámbito de los estudios secundarios ya a fines del siglo XIX, mientras que en la Universidad su arribo fue mucho más tardío, a mediados del siglo pasado. Se analiza la situación actual de esta disciplina, sus problemas, y algunas medidas para fortalecer su desarrollo. Apresentamos, neste trabalho, o desenvolvimento da Astronomia no Uruguai desde a época colonial até o presente, destacando em particular os aspectos vinculados ao seu ensino tanto formal quanto informal. Os primeiros antecedentes de estudos astronômicos em nosso país datam da época colonial relacionados com as expedições científicas do Velho Mundo que chegavam às nossas costas. O ensino da Astronomia se generalizou no âmbito dos estudos secundários já no final do século XIX, enquanto que sua introdução na universidade foi muito mais tardia, em

  17. Sobre a largura da última superfície de espalhamento

    NASA Astrophysics Data System (ADS)

    Nobre, M. A. S.; Pires, N.; Lima, J. A. S.

    2003-08-01

    De acordo com o modelo do "Big-Bang", no universo primordial a matéria estava em equilíbrio térmico com a radiação. Com a expansão a temperatura da radiação cai. Quando a temperatura chega em torno dos 4.000K, os espalhamentos diminuem, começando a recombinação dos prótons e elétrons em Hidrogênio neutro (era conhecida como da recombinação). Ao final da recombinação, os fótons se propagam livremente sofrendo, em princípio, somente os efeitos do "redshift" cosmológico. Esses fótons nos alcançam hoje como a radiação cósmica de fundo (RCF), e parecem vir de uma superfície esférica ao nosso redor, tal que o raio dela é a distância que ele viajou desde seu último espalhamento na época da recombinação. Naturalmente, esse processo não ocorreu abruptamente, implicando na existência de uma largura no espaço dos "redshifts" que deve depender do modelo cosmológico específico e dos processos físicos considerados. Neste trabalho analisamos os efeitos de diferentes modelos - a saber, aqueles com decaimento do vácuo L(t), criação de matéria, quintessência e gás de Chaplygin - sobre a última superfície de espalhamento da RCF, em particular sua largura e a função visibilidade, que determina a probabilidade de um fóton ter tido seu último espalhamento num "redshift" z. No caso particular dos modelos com decaimento do vácuo, existe uma forte dependência da função visibilidade com L(t). Tais efeitos poderão ser testados através da análise dos resultados de experimentos mais precisos que estão atualmente em andamento, como por exemplo, o WMAP.

  18. Health technology assessment (HTA) organizations: dimensions of the institutional and political framework.

    PubMed

    Novaes, Hillegonda Maria Dutilh; Soárez, Patrícia Coelho de

    2016-11-03

    Health technology assessment (HTA) is consolidated as a scientific and technological practice. The aim of this study is to identify HTA organizations from different settings and analyze their relevant dimensions in terms of effectiveness/impact, in order to address the challenges they face in Brazil. Narrative literature review based on data and websites of HTA organizations. There are well-established activity development processes in all organizations. These activities have specific features in their profile, in the process of technology assessment, decision and implementation of technologies that influence their potential impact on health systems. Agencies share in common the challenges of ranking the technologies to be assessed, and the implementation of their recommendations. Technical and political strengthening of the institutionalization of HTA in Brazil may foster scientific, technological and innovation policies, effectively impacting health policies. Resumo: A avaliação de tecnologias em saúde (ATS) está consolidada enquanto prática científica e tecnológica. O objetivo do estudo é identificar organizações de ATS de diferentes contextos e analisá-las de acordo com dimensões relevantes na avaliação de sua efetividade/impacto, buscando contribuir com os desafios enfrentados no contexto nacional. Revisão narrativa da literatura, realizada em bases de dados e web sites de organizações de ATS. Existem processos de desenvolvimento das atividades bem estabelecidos em todas as organizações. Elas apresentam particularidades no seu perfil, nos processos de avaliação, decisão e implementação das tecnologias que influenciam o seu impacto potencial sobre os sistemas de saúde. As agências compartilham os desafios de priorização das tecnologias a serem avaliadas e implementação das suas recomendações. O fortalecimento técnico e político do processo de institucionalização da ATS no contexto nacional poderá contribuir com as pol

  19. Cross-cultural adaptation of the EMIC Stigma Scale for people with leprosy in Brazil.

    PubMed

    Morgado, Fabiane Frota da Rocha; Silveira, Erika Maria Kopp Xavier da; Sales, Anna Maria; Nascimento, Lilian Pinheiro Rodrigues do; Sarno, Euzenir Nunes; Nery, José Augusto da Costa; Oliveira, Aldair J; Illarramendi, Ximena

    2017-09-04

    Describe the process of cross-cultural adaptation of the "Explanatory Model Interview Catalog - Stigma Scale" for people affected by leprosy in Brazil. After being authorized by the author of the scale to use it in the national context, we initiated the five steps process of cross-cultural adaptation: (1) translation, (2) synthesis meeting, (3) back-translation, (4) committee of experts and (5) pre-test. The internal consistency of the scale was evaluated using Cronbach's alpha coefficient. The 15 items of the scale's original version were translated into Brazilian Portuguese. The adapted scale showed evidence of a good understanding of its content, attested both by experts and members of the target population. Its internal consistency was 0.64. The adapted instrument shows satisfactory internal consistency. It may be useful in future studies that intend to provide broad situational analysis that supports solid public health programs with a focus on effective stigma reduction. In a later study, the construct's validity, criterion, and reproducibility will be evaluated. Descrever o processo de adaptação transcultural da "Explanatory Model Interview Catalogue - Stigma Scale" para pessoas afetadas por hanseníase no Brasil. Após a autorização do autor da escala para seu uso no contexto nacional, deu-se início aos cinco passos do processo de adaptação transcultural: (1) tradução, (2) reunião de síntese, (3) retrotradução, (4) comitê de peritos e (5) pré-teste. A consistência interna da escala foi avaliada utilizando o coeficiente alfa de Cronbach. Os 15 itens da versão original da escala foram traduzidos para a língua portuguesa do Brasil. A escala adaptada apresentou evidência de boa compreensão de seu conteúdo, atestada tanto por peritos como por membros da população alvo. Sua consistência interna foi de 0,64. O instrumento adaptado apresenta consistência interna satisfatória. Pode ser útil em estudos futuros que intencionem viabilizar

  20. Investigation of HZETRN 2010 as a Tool for Single Event Effect Qualification of Avionics Systems

    NASA Technical Reports Server (NTRS)

    Rojdev, Kristina; Atwell, William; Boeder, Paul; Koontz, Steve

    2014-01-01

    NASA's future missions are focused on deep space for human exploration that do not provide a simple emergency return to Earth. In addition, the deep space environment contains a constant background Galactic Cosmic Ray (GCR) radiation exposure, as well as periodic Solar Particle Events (SPEs) that can produce intense amounts of radiation in a short amount of time. Given these conditions, it is important that the avionics systems for deep space human missions are not susceptible to Single Event Effects (SEE) that can occur from radiation interactions with electronic components. The typical process to minimizing SEE effects is through using heritage hardware and extensive testing programs that are very costly. Previous work by Koontz, et al. [1] utilized an analysis-based method for investigating electronic component susceptibility. In their paper, FLUKA, a Monte Carlo transport code, was used to calculate SEE and single event upset (SEU) rates. This code was then validated against in-flight data. In addition, CREME-96, a deterministic code, was also compared with FLUKA and in-flight data. However, FLUKA has a long run-time (on the order of days), and CREME-96 has not been updated in several years. This paper will investigate the use of HZETRN 2010, a deterministic transport code developed at NASA Langley Research Center, as another tool that can be used to analyze SEE and SEU rates. The benefits to using HZETRN over FLUKA and CREME-96 are that it has a very fast run time (on the order of minutes) and has been shown to be of similar accuracy as other deterministic and Monte Carlo codes when considering dose [2, 3, 4]. The 2010 version of HZETRN has updated its treatment of secondary neutrons and thus has improved its accuracy over previous versions. In this paper, the Linear Energy Transfer (LET) spectra are of interest rather than the total ionizing dose. Therefore, the LET spectra output from HZETRN 2010 will be compared with the FLUKA and in-flight data to validate

  1. An occupational health programme for adults and children in the carpet weaving industry, Mirzapur, India: a case study in the informal sector.

    PubMed

    Das, P K; Shukla, K P; Ory, F G

    1992-11-01

    The Indo-Dutch Environmental and Sanitary Engineering Project under Ganga action Plan in Kanpur and Mirzapur is being executed within the framework of Indo-Dutch bilateral development cooperation. The project aims to integrate technological, social and health related improvements. It is expected that the development approach and methodology can be replicated in other urban settlements in India. The project is being supplemented by a training and institutional strengthening programme, which will facilitate the transfer of new technologies and improvements in operation and maintenance of these new technologies. One of the project's goals is to improve living conditions in the targeted areas by installing drinking water and drainage systems. A socio-economic unit (SEU) in the project supports these technical interventions by encouraging the community to participate in project activities. The Occupational Health Programme in Mirzapur was conceived by the SEU to improve the health and living conditions of child and adult weavers. At the start of the programme, 200 weavers and 60 non-weaver workers from Mirzapur city, matched for age and socio-economic status, were interviewed and underwent a physical examination. The mean age of the weavers is 27 years, reflecting the relatively large percentage of child labour (13.5%). Illiteracy among them is 73%, whereas 14% have had only a primary education. 64.5% of the carpet weavers are Muslims and 35.6% are Hindus. 61% own a loom or work in a family owned loom shed. 95% of the weavers have a monthly income of less than 600 Rs. Complaints of a persistent cough and cough with expectoration, backache, the common cold and joint pains occurred more often in the weaver population than in the comparison group and have been identified as 'occupational hazards'. An intervention programme has been implemented based on the results of the occupational health survey. These interventions include awareness camps, installment of plexiglass

  2. Fault-Tolerant, Radiation-Hard DSP

    NASA Technical Reports Server (NTRS)

    Czajkowski, David

    2011-01-01

    Commercial digital signal processors (DSPs) for use in high-speed satellite computers are challenged by the damaging effects of space radiation, mainly single event upsets (SEUs) and single event functional interrupts (SEFIs). Innovations have been developed for mitigating the effects of SEUs and SEFIs, enabling the use of very-highspeed commercial DSPs with improved SEU tolerances. Time-triple modular redundancy (TTMR) is a method of applying traditional triple modular redundancy on a single processor, exploiting the VLIW (very long instruction word) class of parallel processors. TTMR improves SEU rates substantially. SEFIs are solved by a SEFI-hardened core circuit, external to the microprocessor. It monitors the health of the processor, and if a SEFI occurs, forces the processor to return to performance through a series of escalating events. TTMR and hardened-core solutions were developed for both DSPs and reconfigurable field-programmable gate arrays (FPGAs). This includes advancement of TTMR algorithms for DSPs and reconfigurable FPGAs, plus a rad-hard, hardened-core integrated circuit that services both the DSP and FPGA. Additionally, a combined DSP and FPGA board architecture was fully developed into a rad-hard engineering product. This technology enables use of commercial off-the-shelf (COTS) DSPs in computers for satellite and other space applications, allowing rapid deployment at a much lower cost. Traditional rad-hard space computers are very expensive and typically have long lead times. These computers are either based on traditional rad-hard processors, which have extremely low computational performance, or triple modular redundant (TMR) FPGA arrays, which suffer from power and complexity issues. Even more frustrating is that the TMR arrays of FPGAs require a fixed, external rad-hard voting element, thereby causing them to lose much of their reconfiguration capability and in some cases significant speed reduction. The benefits of COTS high

  3. Cadmium(II) complex formation with selenourea and thiourea in solution: an XAS and 113Cd NMR study.

    PubMed

    Jalilehvand, Farideh; Amini, Zahra; Parmar, Karnjit

    2012-10-15

    The complexes formed in methanol solutions of Cd(CF(3)SO(3))(2) with selenourea (SeU) or thiourea (TU), for thiourea also in aqueous solution, were studied by combining (113)Cd NMR and X-ray absorption spectroscopy. At low temperature (~200 K), distinct (113)Cd NMR signals were observed, corresponding to CdL(n)(2+) species (n = 0-4, L = TU or SeU) in slow ligand exchange. Peak integrals were used to obtain the speciation in the methanol solutions, allowing stability constants to be estimated. For cadmium(II) complexes with thione (C═S) or selone (C═Se) groups coordinated in Cd(S/Se)O(5) or Cd(S/Se)(2)O(4) (O from MeOH or CF(3)SO(3)(-)) environments, the (113)Cd chemical shifts were quite similar, within 93-97 ppm and 189-193 ppm, respectively. However, the difference in the chemical shift for the Cd(SeU)(4)(2+) (578 pm) and Cd(TU)(4)(2+) (526 ppm) species, with CdSe(4) and CdS(4) coordination, respectively, shows less chemical shielding for the coordinated Se atoms than for S, in contrast to the common trend with increasing shielding in the following order: O > N > Se > S. In solutions dominated by mono- and tetra-thiourea/selenourea complexes, their coordination and bond distances could be evaluated by Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. At ~200 K and high excess of thiourea, a minor amount (up to ~30%) of [Cd(TU)(5-6)](2+) species was detected by an upfield shift of the (113)Cd NMR signal (up to 423 ppm) and an amplitude reduction of the EXAFS oscillation. The amount was estimated by fitting linear combinations of simulated EXAFS spectra for [Cd(TU)(4)](2+) and [Cd(TU)(6)](2+) complexes. At room temperature, [Cd(TU)(4)](2+) was the highest complex formed, also in aqueous solution. Cd L(3)-edge X-ray absorption near edge structure (XANES) spectra of cadmium(II) thiourea solutions in methanol were used to follow changes in the CdS(x)O(y) coordination. The correlations found from the current and previous studies between (113

  4. Cadmium(II) Complex Formation with Selenourea and Thiourea in Solution: An XAS and 113Cd NMR Study

    PubMed Central

    Jalilehvand, Farideh; Amini, Zahra; Parmar, Karnjit

    2012-01-01

    The complexes formed in methanol solutions of Cd(CF3SO3)2 with selenourea (SeU) or thiourea (TU), for thiourea also in aqueous solution, were studied by combining 113Cd NMR and X-ray absorption spectroscopy. At low temperature (~200 K) distinct 113Cd NMR signals were observed, corresponding to CdLn2+ species (n = 0 - 4, L = TU or SeU) in slow ligand exchange. Peak integrals were used to obtain the speciation in the methanol solutions, allowing stability constants to be estimated. For cadmium(II) complexes with thione (C=S) or selone (C=Se) groups coordinated in Cd(S/Se)O5 or Cd(S/Se)2O4 (O from MeOH or CF3SO3-) environments the 113Cd chemical shifts were quite similar, within 93-97 ppm and 189 – 193 ppm, respectively. However, the difference in the chemical shift for the Cd(SeU)42+ (578 pm) and Cd(TU)42+ (526 ppm) species, with CdSe4 and CdS4 coordination, respectively, shows less chemical shielding for the coordinated Se atoms than for S, in contrast to the common trend with increasing shielding in the order: O > N > Se >S. In solutions dominated by mono- and tetra-thiourea / selenourea complexes, their coordination and bond distances could be evaluated by Cd K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy. At ~200 K and high excess of thiourea a minor amount (up to ~30%) of [Cd(TU)5-6]2+ species was detected by an upfield shift of the 113Cd NMR signal (up to 423 ppm) and an amplitude reduction of the EXAFS oscillation. The amount was estimated by fitting linear combinations of simulated EXAFS spectra for [Cd(TU)4]2+ and [Cd(TU)6]2+ complexes. At room temperature, [Cd(TU)4]2+ was the highest complex formed, also in aqueous solution. Cd L3-edge X-ray absorption near edge structure (XANES) spectra of cadmium(II) thiourea solutions in methanol were used to follow changes in the CdSxOy coordination at room temperature. The correlations found from the current and previous studies between 113Cd NMR chemical shifts and different Cd(II) coordination

  5. Otimização de procedimento de manobra para indução de reentrada de um satélite retornável

    NASA Astrophysics Data System (ADS)

    Schulz, W.; Suarez, M.

    2003-08-01

    Veículos espaciais que retornam à Terra passam por regimes de velocidade e condições de vôo distintos. Estas diferenças dificultam sua concepção aerodinâmica e o planejamento de seu retorno. A partir de uma proposta de um veículo orbital retornável (satélite SARA, em desenvolvimento no IAE/CTA) para realização de experimentos científicos e tecnológicos em ambiente de baixa gravidade, surge a necessidade de realizarem-se estudos considerando-se os aspectos relativos à sua aerodinâmica. Após o lançamento, o veículo deve permanecer em órbita pelo tempo necessário para a condução de experimentos, sendo depois direcionado à Terra e recuperado em solo. A concepção aerodinâmica é de importância para o vôo em suas diversas fases e deve considerar aspectos relativos à estabilização Aerodinâmica e ao arrasto atmosférico, sendo este último de importância crucial na análise do aquecimento a ser enfrentado. A manobra de retorno inclui considerações sobre as condições atmosféricas e dinâmica de reentrada, devendo ser calculada de forma mais precisa possível. O trabalho proposto avalia estudos da dinâmica de vôo de um satélite recuperável considerando aspectos relativos à determinação orbital com GPS, técnica utilizada com sucesso na CONAE, e seu comportamento aerodinâmico em vôo balístico de retorno, com ênfase em sua fase de reentrada atmosférica. Busca-se otimizar a manobra de reentrada de tal forma que a utilização do sistema GPS garanta minimizar a área de impacto com o solo.

  6. Prediction Accuracy of Error Rates for MPTB Space Experiment

    NASA Technical Reports Server (NTRS)

    Buchner, S. P.; Campbell, A. B.; Davis, D.; McMorrow, D.; Petersen, E. L.; Stassinopoulos, E. G.; Ritter, J. C.

    1998-01-01

    This paper addresses the accuracy of radiation-induced upset-rate predictions in space using the results of ground-based measurements together with standard environmental and device models. The study is focused on two part types - 16 Mb NEC DRAM's (UPD4216) and 1 Kb SRAM's (AMD93L422) - both of which are currently in space on board the Microelectronics and Photonics Test Bed (MPTB). To date, ground-based measurements of proton-induced single event upset (SEM cross sections as a function of energy have been obtained and combined with models of the proton environment to predict proton-induced error rates in space. The role played by uncertainties in the environmental models will be determined by comparing the modeled radiation environment with the actual environment measured aboard MPTB. Heavy-ion induced upsets have also been obtained from MPTB and will be compared with the "predicted" error rate following ground testing that will be done in the near future. These results should help identify sources of uncertainty in predictions of SEU rates in space.

  7. Nonvolatile Memory Solution for Near-Term NASA Missions

    NASA Technical Reports Server (NTRS)

    Patel, J. U.; Blaes, B. R.; Mojarradi, M. M.

    2001-01-01

    Nonvolatile memory (NVM) system that could reliably function in extreme environments is one of the most critical components for many spacecrafts being developed for NASA missions to be launched in next four to seven years. NVM supports the computer system in saving and updating critical state data required for a warm restart after power cycling or in case of a power bus failure. It also provides a power independent mass storage capacity for the scientific data gathered by the instruments. In some cases the window for gathering such data is very small and occurs only once in a given mission. Commercially popular and fully developed Flash NVM technology is inappropriate for many reasons such as the limited read write cycles with slower access speeds, radiation intolerance, higher Single Event Upsets (SEU) rates, etc. It is desirable to have an NVM system based upon a robust cell technology making it immune to the SEUs and with sufficient radiation hardness. Availability of such NVM system seems to be still 5 to 10 years in the future. Meanwhile, it is possible to provide an interim hybrid solution by combining the existing rad-hard technologies. Additional information is contained in the original extended abstract.

  8. Compendium of Current Single Event Effects for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    O'Bryan, Martha V.; Label, Kenneth A.; Chen, Dakai; Campola, Michael J.; Casey, Megan C.; Lauenstein, Jean-Marie; Pellish, Jonathan A.; Ladbury, Raymond L.; Berg, Melanie D.

    2015-01-01

    NASA spacecraft are subjected to a harsh space environment that includes exposure to various types of ionizing radiation. The performance of electronic devices in a space radiation environment are often limited by their susceptibility to single event effects (SEE). Ground-based testing is used to evaluate candidate spacecraft electronics to determine risk to spaceflight applications. Interpreting the results of radiation testing of complex devices is and adequate understanding of the test condition is critical. Studies discussed herein were undertaken to establish the application-specific sensitivities of candidate spacecraft and emerging electronic devices to single-event upset (SEU), single-event latchup (SEL), single-event gate rupture (SEGR), single-event burnout (SEB), and single-event transient (SET). For total ionizing dose (TID) and displacement damage dose (DDD) results, see a companion paper submitted to the 2015 Institute of Electrical and Electronics Engineers (IEEE) Nuclear and Space Radiation Effects Conference (NSREC) Radiation Effects Data Workshop (REDW) entitled "compendium of Current Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA by M. Campola, et al.

  9. Uranium comparison by means of AMS and ICP-MS and Pu and 137Cs results around an Italian Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    De Cesare, M.; Tims, S. G.; Fifield, L. K.

    2015-04-01

    Italy built and commissioned 4 nuclear power plants between 1958-1978, which delivered a total of 1500 MW. All four were closed down after the Chernobyl accident following a referendum in 1987. One of the plants was Garigliano, commissioned in 1959. This plant used a 160 MW BWR1 (SEU of 2.3 %) and was operational from 1964 to 1979, when it was switched off for maintenance. It was definitively stopped in 1982, and is presently being decommissioned. We report here details on the chemistry procedure and on the measurements for soil samples, collected up to 4.5 km from the Nuclear Plant. A comparison between uranium (238U) concentration as determined by means of AMS (Accelerator Mass Spectrometry) and by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) techniques respectively at the ANU (Australian National University) and at the Ecowise company in Canberra, Australia, is reported, as well as 236U and 239;240Pu concentration results detected by AMS. 236U/238U and 240Pu/239Pu isotopic ratios by means of AMS are also provided. A contamination from Chernobyl is visible in the 137Cs/239+240Pu activity ratio measurements.

  10. The Arabidopsis floral meristem identity genes AP1, AGL24 and SVP directly repress class B and C floral homeotic genes.

    PubMed

    Gregis, Veronica; Sessa, Alice; Dorca-Fornell, Carmen; Kater, Martin M

    2009-11-01

    During the initial stages of flower development, floral meristems increase in size without the formation of floral organs. When a critical meristem size is reached, the floral meristem begins to develop the floral organs. The first stages of flower development are characterized by the expression of genes such as Apetala 1 (AP1), cauliflower (CAL), AGAMOUS-LIKE 24 (AGL24) and short vegetative phase (SVP). We have shown that AP1, AGL24 and SVP act redundantly to control the identity of the floral meristem and to repress expression of class B, C and E genes. Recently, it was shown that class E gene repression was direct and established by two independent pathways. We show here that repression of class B and C genes is also directly established by a co-repressor complex that comprises LEUNIG (LUG), SEUSS (SEU) and the MADS box dimers AP1-AGL24 and AP1-SVP. Furthermore, we show that the distantly related suppressor of overexpression of CO 1 (SOC1) MADS box gene can complement for the loss of AGL24 and SVP activity; however, under normal conditions, this transcription factor does not play a role during the early stages of flower development.

  11. LET spectra measurements of charged particles in the P0006 experiment on LDEF

    NASA Technical Reports Server (NTRS)

    Benton, E. V.; Csige, I.; Oda, K.; Henke, R. P.; Frank, A. L.; Benton, E. R.; Frigo, L. A.; Parnell, T. A.; Watts, J. W., Jr.; Derrickson, J. H.

    1993-01-01

    Measurements are under way of the charged particle radiation environment of the Long Duration Exposure Facility (LDEF) satellite using stacks of plastic nuclear track detectors (PNTD's) placed in different locations of the satellite. In the initial work the charge, energy, and linear energy transfer (LET) spectra of charged particles were measured with CR-39 double layer PNTD's located on the west side of the satellite (Experiment P0006). Primary and secondary stopping heavy ions were measured separately from the more energetic particles. Both trapped and galactic cosmic ray (GCR) particles are included, with the latter component being dominated by relativistic iron particles. The results from the P0006 experiment will be compared with similar measurements in other locations on LDEF with different orientation and shielding conditions. The remarkably detailed investigation of the charged particle radiation environment of the LDEF satellite will lead to a better understanding of the radiation environment of the Space Station Freedom. It will enable more accurate prediction of single event upsets (SEU's) in microelectronics and, especially, more accurate assessment of the risk - contributed by different components of the radiation field (GCR's, trapped protons, secondaries and heavy recoils, etc.) - to the health and safety of crew members.

  12. Formation Control of the MAXIM L2 Libration Orbit Mission

    NASA Technical Reports Server (NTRS)

    Folta, David; Hartman, Kate; Howell, Kathleen; Marchand, Belinda

    2004-01-01

    The Micro-Arcsecond X-ray Imaging Mission (MAXIM), a proposed concept for the Structure and Evolution of the Universe (SEU) Black Hole Imager mission, is designed to make a ten million-fold improvement in X-ray image clarity of celestial objects by providing better than 0.1 micro-arcsecond imaging. Currently the mission architecture comprises 25 spacecraft, 24 as optics modules and one as the detector, which will form sparse sub-apertures of a grazing incidence X-ray interferometer covering the 0.3-10 keV bandpass. This formation must allow for long duration continuous science observations and also for reconfiguration that permits re-pointing of the formation. To achieve these mission goals, the formation is required to cooperatively point at desired targets. Once pointed, the individual elements of the MAXIM formation must remain stable, maintaining their relative positions and attitudes below a critical threshold. These pointing and formation stability requirements impact the control and design of the formation. In this paper, we provide analysis of control efforts that are dependent upon the stability and the configuration and dimensions of the MAXIM formation. We emphasize the utilization of natural motions in the Lagrangian regions to minimize the control efforts and we address continuous control via input feedback linearization (IFL). Results provide control cost, configuration options, and capabilities as guidelines for the development of this complex mission.

  13. Formation Control of the MAXIM L2 Libration Orbit Mission

    NASA Technical Reports Server (NTRS)

    Folta, David; Hartman, Kate; Howell, Kathleen; Marchand, Belinda

    2004-01-01

    The Micro-Arcsecond Imaging Mission (MAXIM), a proposed concept for the Structure and Evolution of the Universe (SEU) Black Hole Imaging mission, is designed to make a ten million-fold improvement in X-ray image clarity of celestial objects by providing better than 0.1 microarcsecond imaging. To achieve mission requirements, MAXIM will have to improve on pointing by orders of magnitude. This pointing requirement impacts the control and design of the formation. Currently the architecture is comprised of 25 spacecraft, which will form the sparse apertures of a grazing incidence X-ray interferometer covering the 0.3-10 keV bandpass. This configuration will deploy 24 spacecraft as optics modules and one as the detector. The formation must allow for long duration continuous science observations and also for reconfiguration that permits re-pointing of the formation. In this paper, we provide analysis and trades of several control efforts that are dependent upon the pointing requirements and the configuration and dimensions of the MAXIM formation. We emphasize the utilization of natural motions in the Lagrangian regions that minimize the control efforts and we address both continuous and discrete control via LQR and feedback linearization. Results provide control cost, configuration options, and capabilities as guidelines for the development of this complex mission.

  14. Multi-physics modelling contributions to investigate the atmospheric cosmic rays on the single event upset sensitivity along the scaling trend of CMOS technologies.

    PubMed

    Hubert, G; Regis, D; Cheminet, A; Gatti, M; Lacoste, V

    2014-10-01

    Particles originating from primary cosmic radiation, which hit the Earth's atmosphere give rise to a complex field of secondary particles. These particles include neutrons, protons, muons, pions, etc. Since the 1980s it has been known that terrestrial cosmic rays can penetrate the natural shielding of buildings, equipment and circuit package and induce soft errors in integrated circuits. Recently, research has shown that commercial static random access memories are now so small and sufficiently sensitive that single event upsets (SEUs) may be induced from the electronic stopping of a proton. With continued advancements in process size, this downward trend in sensitivity is expected to continue. Then, muon soft errors have been predicted for nano-electronics. This paper describes the effects in the specific cases such as neutron-, proton- and muon-induced SEU observed in complementary metal-oxide semiconductor. The results will allow investigating the technology node sensitivity along the scaling trend. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. A built-in SRAM for radiation hard CMOS pixel sensors dedicated to high energy physics experiments

    NASA Astrophysics Data System (ADS)

    Wei, Xiaomin; Gao, Deyuan; Doziere, Guy; Hu, Yann

    2013-02-01

    CMOS pixel sensors (CPS) are attractive candidates for charged particle tracking in high energy physics experiments. However, CPS chips fabricated with standard CMOS processes, especially the built-in SRAM IP cores, are not radiation hard enough for this application. This paper presents a radiation hard SRAM for improving the CPS radiation tolerance. The SRAM cell is hardened by increasing the static noise margin (SNM) and adding P+ guard rings in layout. The peripheral circuitry is designed by building a radiation-hardened logic library. The SRAM internal timing control is hardened by a self-adaptive timing design. Finally, the SRAM design was implemented and tested in the Austriamicrosystems (AMS) 0.35 μm standard CMOS process. The prototype chips are adapted to work with frequencies up to 80 MHz, power supply voltages from 2.9 V to 3.3 V and temperatures from 0 °C to 60 °C. The single event latchup (SEL) tolerance is improved from 5.2 MeV cm2/mg to above 56 MeV cm2/mg. The total ionizing dose (TID) tolerance is enhanced by the P+ guard rings and the self-adaptive timing design. The single event upset (SEU) effects are also alleviated due to the high SNM SRAM cell and the P+ guard rings. In the near future, the presented SRAM will be integrated in the CPS chips for the STAR experiments.

  16. An expert system for diagnosing environmentally induced spacecraft anomalies

    NASA Technical Reports Server (NTRS)

    Rolincik, Mark; Lauriente, Michael; Koons, Harry C.; Gorney, David

    1992-01-01

    A new rule-based, machine independent analytical tool was designed for diagnosing spacecraft anomalies using an expert system. Expert systems provide an effective method for saving knowledge, allow computers to sift through large amounts of data pinpointing significant parts, and most importantly, use heuristics in addition to algorithms, which allow approximate reasoning and inference and the ability to attack problems not rigidly defined. The knowledge base consists of over two-hundred (200) rules and provides links to historical and environmental databases. The environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. The use of heuristics frees the user from searching through large amounts of irrelevant information and allows the user to input partial information (varying degrees of confidence in an answer) or 'unknown' to any question. The modularity of the expert system allows for easy updates and modifications. It not only provides scientists with needed risk analysis and confidence not found in algorithmic programs, but is also an effective learning tool, and the window implementation makes it very easy to use. The system currently runs on a Micro VAX II at Goddard Space Flight Center (GSFC). The inference engine used is NASA's C Language Integrated Production System (CLIPS).

  17. Nodular trombiculinosis caused by Apolonia tigipioensis, Torres and Braga (1938), in an ostrich (Struthio camelus) and a house sparrow (Passer domesticus).

    PubMed

    Ornelas-Almeida, Maria Angela; de Oliveira, Flávio Ramos Bastos; da Silva, Alessandra Estrela; Moreira, Eduardo Luiz Trindade; Maia, Paulo César Costa; de Fátima Cardoso Duarte, Larissa; Murphy, Gleeson; Ayres, Maria Consuelo Caribe

    2007-12-25

    Nodular trombiculinosis has been reported in Brazil in chickens [Torres, S., Braga, W., 1939. Apolonia tigipioensis, g. e sp. n. (Trombiculinae) parasito de Gallus gallus dom. Chave para determinação de gêneros. Boletim da S.A.I.C. 4, 37-44] and humans [Carneiro, L.S., 1952. Uma nova acaríase humana - Contribuição ao seu estudo. Imprensa Industrial, Recife. Faculdade de Medicina da Universidade do Recife, Tese Livre Docência, p. 56]. In this report, a juvenile ostrich and a house sparrow, both originating from a riverside property in the town of Petrolina in the state of Pernambuco, presented 87 and eight nodules, respectively, on various locations of their bodies. Physical expression of the nodules liberated parasites that were morphologically identified as mites from the family Trombiculidae. The mites were further identified as Apolonia tigipioensis by the presence of an elongated body form and transversely striated, three pairs of long legs each with seven segments, primary coxae with a single seta, each tarsus terminating with three claws, and a scutum with an anteromedian projection and paired anteromedian setae. Histopathologic examination of skin biopsies from these birds, stained with hematoxilin-eosin, revealed acute parasitic cystic lymphoplasmacytic dermatitis.

  18. Cometas: Das Lendas aos Fatos

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    O descobrimento de cometas, devido ao seu aparecimento espetacular, tem registro nas mais antigas culturas humanas. A primeira referência situa-se no ano de 1095 antes de Cristo [a.C.; HO; HO, 1962]. A quantidade de registros de descobrimentos cometários, principalmente provenientes do território chinês em particular e do oriente em geral, aumentou gradualmente a partir do quarto século depois de Cristo (d.C.). É de origem chinesa a primeira referência ao cometa P/Halley no ano de 240 a.C. [VOELZKE, 1993]. Com o desenvolvimento da astronomia relativamente às técnicas observacionais os descobrimentos bem como as observações cometárias aumentaram sensivelmente a partir do século XVII, sendo que a partir do século XIX um novo incremento ocorreu devido ao emprego da fotografia e a resultante melhora de sensibilidade na observação.

  19. Astragaloside IV for Experimental Focal Cerebral Ischemia: Preclinical Evidence and Possible Mechanisms

    PubMed Central

    Wang, Hui-Lin; Zhou, Qi-Hui; Xu, Meng-Bei; Zhou, Xiao-Li

    2017-01-01

    Astragaloside IV (AST-IV) is a principal component of Radix Astragali seu Hedysari (Huangqi) and exerts potential neuroprotection in experimental ischemic stroke. Here, we systematically assessed the effectiveness and possible mechanisms of AST-IV for experimental acute ischemic stroke. An electronic search in eight databases was conducted from inception to March 2016. The study quality score was evaluated using the CAMARADES. Rev Man 5.0 software was used for data analyses. Thirteen studies with 244 animals were identified. The study quality score of included studies ranged from 3/10 to 8/10. Eleven studies showed significant effects of AST-IV for ameliorating the neurological function score (P < 0.05); seven studies for reducing the infarct volume (P < 0.05); and three or two studies for reducing the brain water content and Evans blue leakage (P < 0.05), respectively, compared with the control. The mechanisms of AST-IV for ischemic stroke are multiple such as antioxidative/nitration stress reaction, anti-inflammatory, and antiapoptosis. In conclusion, the findings of present study indicated that AST-IV could improve neurological deficits and infarct volume and reduce the blood-brain barrier permeability in experimental cerebral ischemia despite some methodological flaws. Thus, AST-IV exerted a possible neuroprotective effect during the cerebral ischemia/reperfusion injury largely through its antioxidant, anti-inflammatory, and antiapoptosis properties. PMID:28303172

  20. High LET Single Event Upset Cross Sections For Bulk and SOI CMOS SRAMs

    SciTech Connect

    McDaniel, F.D.; Doyle, B.L.; Vizkelethy, G.; Dodd, P.E.; Rossi, P.

    2003-08-26

    Electronics in spacecraft and satellites are exposed to high-energy cosmic radiation. In addition, terrestrial radiation can also affect earth-based electronics. To study the effects of radiation upon integrated circuits and to insure the reliability of electronic devices, cosmic and terrestrial radiations are simulated with ion beams from particle accelerators. A new, higher Linear Energy Transfer (LET) acceleration system for heavy ions has been developed at Sandia National Laboratories. Heavy ions from a 6.5 MV EN tandem Van de Graaff accelerator at 0.25 MeV/amu are injected into a two-stage Radio Frequency Quadrupole (RFQ) linac, which accelerates the ions to 1.9 MeV/amu. These ions together with those from the Brookhaven National Laboratory MP Tandem have been used to measure single event upset (SEU) cross sections as a function of LET for both bulk and Silicon on Insulator (SOI) Complementary Metal Oxide Semiconductor, Static Random Access Memories. The magnitudes of these cross sections indicate that the upsets in both the SOI and bulk parts are caused by OFF-drain strikes.

  1. Single Event Effect Testing of the Analog Devices ADV212

    NASA Technical Reports Server (NTRS)

    Wilcox, Ted; Campola, Michael; Kadari, Madhu; Nadendla, Seshagiri R.

    2017-01-01

    The Analog Devices ADV212 was initially tested for single event effects (SEE) at the Texas AM University Cyclotron Facility (TAMU) in July of 2013. Testing revealed a sensitivity to device hang-ups classified as single event functional interrupts (SEFI), soft data errors classified as single event upsets (SEU), and, of particular concern, single event latch-ups (SEL). All error types occurred so frequently as to make accurate measurements of the exposure time, and thus total particle fluence, challenging. To mitigate some of the risk posed by single event latch-ups, circuitry was added to the electrical design to detect a high current event and automatically recycle power and reboot the device. An additional heavy-ion test was scheduled to validate the operation of the recovery circuitry and the continuing functionality of the ADV212 after a substantial number of latch-up events. As a secondary goal, more precise data would be gathered by an improved test method, described in this test report.

  2. Preliminary test results for the SVX4

    SciTech Connect

    Christofek, L.; Hanagaki, K.; Rapidis, P.; Utes, M.; /Fermilab

    2005-06-01

    We present and summarize the preliminary test results for SVX4 chip testing. There are presently two versions of the SVX4. Version 2 has on-chip bypassing and Version 1 does not. The on-chip bypassing is a layer of transistors under the front-end analog pipeline that acts as a bypassing capacitor for the voltage supply. Its size is about a microfarad. We aggressively choose to test Version 2 because of this feature. The feature is advantageous for hybrid design because it eliminates the need for an additional passive component on the hybrid itself by placing it on the actual SVX4 die. Also, the SVX4 was designed to operate in two modes: D. and CDF. One can set which mode the chip will operate by placing a jumper in the proper position on the SVX4 chip carrier. In either mode, the chip can either use the operating parameters from the shift register or the shadow register. Similarly, this is selected by placing a jumper on the SVX4 chip carrier. This chip has this feature because it was unknown whether the new design of the shadow register would be operable. The shadow register is also call the SEU register or Single Event Upset register. An introduction into the functionality of the chip and an explanation on the difference between D. and CDF mode can be found in the SVX4 User's Manual [1].

  3. Effects of space radiation on electronic microcircuits

    NASA Technical Reports Server (NTRS)

    Kolasinski, W. A.

    1989-01-01

    The single event effects or phenomena (SEP), which so far have been observed as events falling on one or another of the SE classes: Single Event Upset (SEU), Single Event Latchup (SEL) and Single Event Burnout (SEB), are examined. Single event upset is defined as a lasting, reversible change in the state of a multistable (usually bistable) electronic circuit such as a flip-flop or latch. In a computer memory, SEUs manifest themselves as unexplained bit flips. Since latchup is in general caused by a single event of short duration, the single event part of the SEL term is superfluous. Nevertheless, it is used customarily to differentiate latchup due to a single heavy charged particle striking a sensitive cell from more ordinary kinds of latchup. Single event burnout (SEB) refers usually to total instantaneous failure of a power FET when struck by a single particle, with the device shorting out the power supply. An unforeseen failure of these kinds can be catastrophic to a space mission, and the possibilities are discussed.

  4. Método numérico das diferenças finitas no domínio do tempo aplicado a ondas Alfvén em plasma astrofísico

    NASA Astrophysics Data System (ADS)

    Dos Santos, L. C.; Kintopp, J. A.; Jatenco-Pereira, V.; Opher, R.

    2003-08-01

    Ondas Alfvén em plasma astrofísico têm sido objeto de intenso estudo nas últimas décadas pelo fato de apresentarem papel importante em muitas áreas de pesquisa na astrofísica. Particularmente são importantes no mecanismo de aquecimento da coroa solar; em ventos estelares; em jatos galácticos e extragalácticos; em discos protoestelares, etc. A formulação para diferenças finitas no domínio do tempo (FDTD), aplicada a plasma magnetizado é desenvolvida para estudo das propriedades de ondas Alfvén em três dimensões (3D-FDTD). O método é aplicado inicialmente a um plasma homogêneo e isotérmico imerso em uma região com campo magnético externo B0, que sofre uma pequena perturbação. Uma vez gerada a onda, esta perturbação é retirada e, então analisamos a evolução temporal das ondas, bem como a forma de seu amortecimento.

  5. Multivitamin supplementation and multiple births.

    PubMed

    Werler, M M; Cragan, J D; Wasserman, C R; Shaw, G M; Erickson, J D; Mitchell, A A

    1997-07-11

    It is well established that maternal multivitamin supplementation reduces the risk of neural tube defects and evidence suggests that it may be associated with other reproductive outcomes. The present study was prompted by a report from a randomized trial in Hungary which showed a 40% increase in multiple births among periconceptional vitamin users. Retrospectively collected data on multivitamin supplementation were obtained on multiple and singleton births from three separate studies: Atlanta Birth Defects Case-Control Study (ABDCCS) malformed and nonmalformed infants born 1968-1980, California Birth Defects Monitoring Program (CBDMP) malformed and nonmalformed infants born 1987-1989, and Boston University Slone Epidemiology Unit Birth Defects Study (SEU-BDS) malformed infants born 1987-1994. Supplementation was divided into three mutually exclusive categories based on timing: "periconceptional" use--before through at least the third month after conception; "early" use--beginning in the first month and continuing through at least the third month after conception; and "later" use--beginning in the second or third month after conception. For periconceptional use, four of five datasets showed a 30 to 60% greater prevalence of supplementation among mothers of multiple births. In contrast, this pattern was not evident for "early" and "later" use. Overall, the study findings are tentative, due to a lack of consistency across all five datasets and they should not alter recent recommendations related to folate supplementation for the prevention of neural tube defects.

  6. South Atlantic anomaly and CubeSat design considerations

    NASA Astrophysics Data System (ADS)

    Fennelly, Judy A.; Johnston, William R.; Ober, Daniel M.; Wilson, Gordon R.; O'Brien, T. Paul; Huston, Stuart L.

    2015-09-01

    Effects of the South Atlantic Anomaly (SAA) on spacecraft in low Earth orbit (LEO) are well known and documented. The SAA exposes spacecraft in LEO to high dose of ionizing radiation as well as higher than normal rates of Single Event Upsets (SEU) and Single Event Latch-ups (SEL). CubeSats, spacecraft built around 10 x 10 x 10 cm cubes, are even more susceptible to SEUs and SELs due to the use of commercial off-the-shelf components for electronics and payload instrumentation. Examination of the SAA using both data from the Defense Meteorological Satellite Program (DMSP) and a new set of models for the flux of particles is presented. The models, AE9, AP9, and SPM for energetic electrons, energetic protons and space plasma, were developed for use in space system design. These models introduce databased statistical constraints on the uncertainties from measurements and climatological variability. Discussion of the models' capabilities and limitations with regard to LEO CubeSat design is presented.

  7. Screening, detection, and serotyping methods for toxin genes and enterotoxins in Staphylococcus strains.

    PubMed

    Hait, Jennifer M; Tallent, Sandra M; Bennett, Reginald W

    2014-01-01

    Staphylococcus aureus continues to play a significant role in foodborne outbreak investigations, with numerous individuals sickened each year after ingesting assorted foods contaminated with staphylococcal enterotoxins. The purpose of this study was to evaluate the use of several methods for the screening, detection, and enterotoxin serotyping of staphylococcal bacterial strains for classical staphylococcal enterotoxins (SEs; SEA, SEB, SEC, SED, and SEE) and the newly described SE and SE-like enterotoxin genes (seg, seh, sei, sej, sek, sel, sem, sen, seo, sep, seq, ser, ses, set, and seu). Inclusivity and exclusivity panels of staphylococcal strains were tested using a multiplex PCR method in addition to three polyvalent commercially prepared ELISA systems for the detection of SEA-SEE and one monovalent assay for the identification of classical SE serotypes. The results indicate an overall agreement between serological detection methods with a few exceptions, and molecular characterization identified an abundance of SE and SE-like enterotoxin genes including several potentially enterotoxigenic isolates that would have otherwise been missed by ELISA-based methods. These findings demonstrate the significance of PCR for future screening purposes and the use of ELISA systems for the detection and enterotoxin serotyping of staphylococcal bacterial strains.

  8. The pixel detector readout ASIC for the MicroVertex Detector of the PANDA experiment

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Calvo, D.; De Remigis, P.; Kugathasan, T.; Mignone, M.; Rivetti, A.; Toscano, L.; Wheadon, R.

    2013-08-01

    The silicon pixel detector of the PANDA experiment is characterized by both high track density and the absence of a hardware trigger signal, thus leading to a huge amount of data to be acquired and transmitted to the DAQ. In order to cope with such challenging requirements, an ASIC based custom solution for the electronic readout has been chosen. The ASIC, named ToPiX, will provide the time position of each hit and a measure of the charge released with the Time over Threshold (ToT) technique. A reduced scale prototype in a CMOS 0.13 μm technology has been designed and tested. The prototype includes four columns made of 128 pixel cells, four columns of 32 cells and the end of column readout with a 32 cells deep FIFO for each double column. Each cell embeds a charge amplifier with constant current feedback capacitor discharge, a comparator with per cell adjustable threshold, 12-bits leading and trailing edge register for time and ToT measurement and an 8 bits configuration register. All the readout logic has been SEU-hardened by design using either Hamming encoding or triple modular redundancy. The chip has been tested both electrically via a test pulse input and connected to a detector in a beam test.

  9. Group A rotavirus gastroenteritis: post-vaccine era, genotypes and zoonotic transmission.

    PubMed

    Luchs, Adriana; Timenetsky, Maria do Carmo Sampaio Tavares

    2016-01-01

    ABSTRACTThis article provides a review of immunity, diagnosis, and clinical aspects of rotavirus disease. It also informs about the changes in epidemiology of diarrheal disease and genetic diversity of circulating group A rotavirus strains following the introduction of vaccines. Group A rotavirus is the major pathogen causing gastroenteritis in animals. Its segmented RNA genome can lead to the emergence of new or unusual strains in human populations via interspecies transmission and/or reassortment events.RESUMOEste artigo fornece uma revisão sobre imunidade, diagnóstico e aspectos clínicos da doença causada por rotavírus. Também aponta as principais mudanças no perfil epidemiológico da doença diarreica e na diversidade genética das cepas circulantes de rotavírus do grupo A, após a introdução vacinal. O rotavírus do grupo A é o principal patógeno associado à gastroenterite em animais. Seu genoma RNA segmentado pode levar ao surgimento de cepas novas ou incomuns na população humana, por meio de transmissão entre espécies e eventos de rearranjo.

  10. A correlação índice espectral vs. luminosidade em QSOs e suas implicações

    NASA Astrophysics Data System (ADS)

    Garcia-Rissmann, A.

    2003-08-01

    Estudos de variabilidade de núcleos ativos já demonstraram ser comum o fato de seu contínuo óptico/UV tornar-se mais "duro" à medida que a luminosidade aumenta. Essa tendência ocorre tanto de forma individual quanto global, e pode ter implicações importantes (1) para estudos fotométricos de variabilidade conduzidos numa banda fixa no referencial do observador, comparando objetos a diferentes redshifts, e (2) no cálculo da correção K, com consequente impacto na determinação de massas de buracos negros e bojos de galáxias hospedeiras (através da relação de Magorrian). Confirmo aqui as correlações positivas entre o índice espectral e a luminosidade óptica, utilizando dados espectroscópicos de 11 QSOs monitorados no Brasil e no Chile, durante ~2 anos. O estudo é complementado com parâmetros extraídos de espectros e de dados fotométricos públicos de quasares. Destaco ainda as diferenças observadas em tais correlações para objetos do tipo radio-loud e radio-quiet. Este projeto é financiado pelo I. Milênio/CNPq.

  11. Low energy CMOS for space applications

    NASA Technical Reports Server (NTRS)

    Panwar, Ramesh; Alkalaj, Leon

    1992-01-01

    The current focus of NASA's space flight programs reflects a new thrust towards smaller, less costly, and more frequent space missions, when compared to missions such as Galileo, Magellan, or Cassini. Recently, the concept of a microspacecraft was proposed. In this concept, a small, compact spacecraft that weighs tens of kilograms performs focused scientific objectives such as imaging. Similarly, a Mars Lander micro-rover project is under study that will allow miniature robots weighing less than seven kilograms to explore the Martian surface. To bring the microspacecraft and microrover ideas to fruition, one will have to leverage compact 3D multi-chip module-based multiprocessors (MCM) technologies. Low energy CMOS will become increasingly important because of the thermodynamic considerations in cooling compact 3D MCM implementations and also from considerations of the power budget for space applications. In this paper, we show how the operating voltage is related to the threshold voltage of the CMOS transistors for accomplishing a task in VLSI with minimal energy. We also derive expressions for the noise margins at the optimal operating point. We then look at a low voltage CMOS (LVCMOS) technology developed at Stanford University which improves the power consumption over conventional CMOS by a couple of orders of magnitude and consider the suitability of the technology for space applications by characterizing its SEU immunity.

  12. Experiment in Onboard Synthetic Aperture Radar Data Processing

    NASA Technical Reports Server (NTRS)

    Holland, Matthew

    2011-01-01

    Single event upsets (SEUs) are a threat to any computing system running on hardware that has not been physically radiation hardened. In addition to mandating the use of performance-limited, hardened heritage equipment, prior techniques for dealing with the SEU problem often involved hardware-based error detection and correction (EDAC). With limited computing resources, software- based EDAC, or any more elaborate recovery methods, were often not feasible. Synthetic aperture radars (SARs), when operated in the space environment, are interesting due to their relevance to NASAs objectives, but problematic in the sense of producing prodigious amounts of raw data. Prior implementations of the SAR data processing algorithm have been too slow, too computationally intensive, and require too much application memory for onboard execution to be a realistic option when using the type of heritage processing technology described above. This standard C-language implementation of SAR data processing is distributed over many cores of a Tilera Multicore Processor, and employs novel Radiation Hardening by Software (RHBS) techniques designed to protect the component processes (one per core) and their shared application memory from the sort of SEUs expected in the space environment. The source code includes calls to Tilera APIs, and a specialized Tilera compiler is required to produce a Tilera executable. The compiled application reads input data describing the position and orientation of a radar platform, as well as its radar-burst data, over time and writes out processed data in a form that is useful for analysis of the radar observations.

  13. Reliability concerns with logical constants in Xilinx FPGA designs

    SciTech Connect

    Quinn, Heather M; Graham, Paul; Morgan, Keith; Ostler, Patrick; Allen, Greg; Swift, Gary; Tseng, Chen W

    2009-01-01

    In Xilinx Field Programmable Gate Arrays logical constants, which ground unused inputs and provide constants for designs, are implemented in SEU-susceptible logic. In the past, these logical constants have been shown to cause the user circuit to output bad data and were not resetable through off-line rcconfiguration. In the more recent devices, logical constants are less problematic, though mitigation should still be considered for high reliability applications. In conclusion, we have presented a number of reliability concerns with logical constants in the Xilinx Virtex family. There are two main categories of logical constants: implicit and explicit logical constants. In all of the Virtex devices, the implicit logical constants are implemented using half latches, which in the most recent devices are several orders of magnitudes smaller than configuration bit cells. Explicit logical constants are implemented exclusively using constant LUTs in the Virtex-I and Virtex-II, and use a combination of constant LUTs and architectural posts to the ground plane in the Virtex-4. We have also presented mitigation methods and options for these devices. While SEUs in implicit and some types of explicit logical constants can cause data corrupt, the chance of failure from these components is now much smaller than it was in the Virtex-I device. Therefore, for many cases, mitigation might not be necessary, except under extremely high reliability situations.

  14. Non-volatile, high density, high speed, Micromagnet-Hall effect Random Access Memory (MHRAM)

    NASA Technical Reports Server (NTRS)

    Wu, Jiin C.; Katti, Romney R.; Stadler, Henry L.

    1991-01-01

    The micromagnetic Hall effect random access memory (MHRAM) has the potential of replacing ROMs, EPROMs, EEPROMs, and SRAMs because of its ability to achieve non-volatility, radiation hardness, high density, and fast access times, simultaneously. Information is stored magnetically in small magnetic elements (micromagnets), allowing unlimited data retention time, unlimited numbers of rewrite cycles, and inherent radiation hardness and SEU immunity, making the MHRAM suitable for ground based as well as spaceflight applications. The MHRAM device design is not affected by areal property fluctuations in the micromagnet, so high operating margins and high yield can be achieved in large scale integrated circuit (IC) fabrication. The MHRAM has short access times (less than 100 nsec). Write access time is short because on-chip transistors are used to gate current quickly, and magnetization reversal in the micromagnet can occur in a matter of a few nanoseconds. Read access time is short because the high electron mobility sensor (InAs or InSb) produces a large signal voltage in response to the fringing magnetic field from the micromagnet. High storage density is achieved since a unit cell consists only of two transistors and one micromagnet Hall effect element. By comparison, a DRAM unit cell has one transistor and one capacitor, and a SRAM unit cell has six transistors.

  15. Nonvolatile Memory Solution for Near-Term NASA Missions

    NASA Technical Reports Server (NTRS)

    Patel, J. U.; Blaes, B. R.; Mojarradi, M. M.

    2001-01-01

    Nonvolatile memory (NVM) system that could reliably function in extreme environments is one of the most critical components for many spacecrafts being developed for NASA missions to be launched in next four to seven years. NVM supports the computer system in saving and updating critical state data required for a warm restart after power cycling or in case of a power bus failure. It also provides a power independent mass storage capacity for the scientific data gathered by the instruments. In some cases the window for gathering such data is very small and occurs only once in a given mission. Commercially popular and fully developed Flash NVM technology is inappropriate for many reasons such as the limited read write cycles with slower access speeds, radiation intolerance, higher Single Event Upsets (SEU) rates, etc. It is desirable to have an NVM system based upon a robust cell technology making it immune to the SEUs and with sufficient radiation hardness. Availability of such NVM system seems to be still 5 to 10 years in the future. Meanwhile, it is possible to provide an interim hybrid solution by combining the existing rad-hard technologies. Additional information is contained in the original extended abstract.

  16. DNABP: Identification of DNA-Binding Proteins Based on Feature Selection Using a Random Forest and Predicting Binding Residues

    PubMed Central

    Guo, Jing; Sun, Xiao

    2016-01-01

    DNA-binding proteins are fundamentally important in cellular processes. Several computational-based methods have been developed to improve the prediction of DNA-binding proteins in previous years. However, insufficient work has been done on the prediction of DNA-binding proteins from protein sequence information. In this paper, a novel predictor, DNABP (DNA-binding proteins), was designed to predict DNA-binding proteins using the random forest (RF) classifier with a hybrid feature. The hybrid feature contains two types of novel sequence features, which reflect information about the conservation of physicochemical properties of the amino acids, and the binding propensity of DNA-binding residues and non-binding propensities of non-binding residues. The comparisons with each feature demonstrated that these two novel features contributed most to the improvement in predictive ability. Furthermore, to improve the prediction performance of the DNABP model, feature selection using the minimum redundancy maximum relevance (mRMR) method combined with incremental feature selection (IFS) was carried out during the model construction. The results showed that the DNABP model could achieve 86.90% accuracy, 83.76% sensitivity, 90.03% specificity and a Matthews correlation coefficient of 0.727. High prediction accuracy and performance comparisons with previous research suggested that DNABP could be a useful approach to identify DNA-binding proteins from sequence information. The DNABP web server system is freely available at http://www.cbi.seu.edu.cn/DNABP/. PMID:27907159

  17. Psychiatry training towards a global future: trainees' perspective in Portugal.

    PubMed

    Pinto da Costa, Mariana; Guerra, Cátia; Malta, Rui; Moura, Manuela; Carvalho, Serafim; Mendonça, Denisa

    2013-01-01

    Introdução: A psiquiatria é influenciada pelas mudanças que ocorrem na sociedade, devendo estar em constante renovação, antevendo futuros comportamentos e doenças. Este estudo pretende descrever a opinião dos internos de psiquiatria em Portugal relativamente ao seu internato e às modificações que nele gostariam de assistir no futuro próximo.Material e Métodos: Um questionário estruturado de 26 perguntas foi desenvolvido pela Associação Portuguesa de Internos de Psiquiatria e enviado por email.Resultados: A percentagem de respostas obtidas foi de 41,5%. A maioria dos internos estava satisfeita com a sua formação. Contudo, algumas mudanças foram sugeridas no que diz respeitos aos estágios obrigatórios e opcionais. A maior parte dos internos requer que as psicoterapias sejam incluídas no âmbito do internato, solicitando também um acesso mais fácil à investigação e a oportunidades de estágio no estrangeiro.Discussão e Conclusão: Esta perspectiva detalhada pode facilitar a transformação dos currículos do internato em Portugal e naEuropa, permitindo a melhoria do internato de psiquiatria, bem como dos cuidados de saúde mental.

  18. Perfil de temperatura dos funis magnetosféricos de estrelas T Tauri com aquecimento alfvênico

    NASA Astrophysics Data System (ADS)

    Vasconcelos, M. J.

    2003-08-01

    Estrelas T Tauri Clássicas são objetos jovens circundados por discos de gás e poeira e que apresentam uma intensa atividade magnética. Seu espectro mostra linhas de emissão alargadas que são razoavelmente reproduzidas nos modelos de acresção magnetosférica. No entanto, o perfil de temperatura dos funis magnéticos é desconhecido. Aquecimento magnético compressional e difusão ambipolar foram considerados para estas estruturas, porém as temperaturas obtidas não são suficientes para explicar as observações. Neste trabalho, examinamos o aquecimento gerado pelo amortecimento de ondas Alfvén através de quatro mecanismos, os amortecimentos não-linear, turbulento, viscoso-resistivo e colisional como função da freqüência da onda. Inicialmente, a temperatura é ajustada para reproduzir as observações e o grau de turbulência requerido para que o mecanismo seja viável é calculado. Os resultados mostram que este é compatível com os dados observacionais. Apresentam-se, também, resultados preliminares do cálculo auto-consistente do perfil de temperatura dos funis, levando-se em conta fontes de aquecimento Alfvênica e fontes de resfriamento.

  19. [Textual research on adulteration of Chinese materia medica in ancient China].

    PubMed

    Xie, Jin; Wang, De-Qun

    2013-09-01

    By investigating the mainstream works of herbal classics of successive ages, it is found that adulteration of Chinese materia medica appeared early in ancient China. The main methods of adulteration was producing fraud medicines in the Northern-Southern Dynasties, fake medicines began to appear in the Tang Dynasty, and status of adulteration of Chinese materia medica ran unchecked since the Ming and Qing Dynasty. By statistics, there were 76 kinds of adulteration varieties before the Republican period. The main varieties were precious drugs, animal drugs and artifacts. Commonly methods used in the process included forging and adulterating, dealing with 11 kinds and 68 kinds respectively. Adulteration probably lead to the result of imposing the changes of the used medicinal parts of Herba Pogostemonis; Radix Aconiti Lateralis prepared by adding salt, Radix Angelica Sinensis processed by wine, and Radix Astragalis seu Hedysaris processed with bee honey. However, the root cause of adulteration in Chinese materia medica was the dissociation of professional physician and pharmacist, resulting in the ignorance of medical practitioners became unable to recognize Chinese materia medica; and the immorality of medicinal merchants. Besides, rating the quality of materia medica based on its producing areas without differentiating the false from the genuine may also contribute to this result passively.

  20. Thermographic phosphor strain measurements. Final report

    SciTech Connect

    Allison, S.W.; Capps, G.J.; Smith, D.B.; Cates, M.R.; Gleason, J.; Turley, W.D.

    1994-05-01

    This report describes the first phase of research aimed at developing a high-temperature strain gauge for power equipment use based on materials whose fluorescence characteristics are affected by strain. In electric power generating plants, the combined effect of temperature and strain on equipment and structures is a critical factor in safe, efficient operation and component lifetime. For the first part of this project, the pressure responses of phosphor and crystalline materials were surveyed. Next, pressure measurements on some promising materials, YVO{sub 4}:Dy and Gd{sub 2}O{sub 2}S:Tb, were performed. The latter phosphor appears to exhibit the greatest change with pressure. Its fluorescence lifetime decreases by a factor of 10 with pressure increase of 20 kbar. In a strain test configuration, a tapered sapphire rod compressed a similar phosphor material, La{sub 2}O{sub 2}S:Eu. The intensity level increased, as expected for this material, with compression. Both of the oxysulfide materials possess potential for use in an optical strain gauge for temperatures up to at least 300{degrees}C. It is suggested that a mixture of these two materials may be a useful way to obtain the maximum pressure or strain sensitivity.

  1. Plug-and-Play Environmental Monitoring Spacecraft Subsystem

    NASA Technical Reports Server (NTRS)

    Patel, Jagdish; Brinza, David E.; Tran, Tuan A.; Blaes, Brent R.

    2011-01-01

    A Space Environment Monitor (SEM) subsystem architecture has been developed and demonstrated that can benefit future spacecraft by providing (1) real-time knowledge of the spacecraft state in terms of exposure to the environment; (2) critical, instantaneous information for anomaly resolution; and (3) invaluable environmental data for designing future missions. The SEM architecture consists of a network of plug-and- play (PnP) Sensor Interface Units (SIUs), each servicing one or more environmental sensors. The SEM architecture is influenced by the IEEE Smart Transducer Interface Bus standard (IEEE Std 1451) for its PnP functionality. A network of PnP Spacecraft SIUs is enabling technology for gathering continuous real-time information critical to validating spacecraft health in harsh space environments. The demonstrated system that provided a proof-of-concept of the SEM architecture consisted of three SIUs for measurement of total ionizing dose (TID) and single event upset (SEU) radiation effects, electromagnetic interference (EMI), and deep dielectric charging through use of a prototype Internal Electro-Static Discharge Monitor (IESDM). Each SIU consists of two stacked 2X2 in. (approximately 5X5 cm) circuit boards: a Bus Interface Unit (BIU) board that provides data conversion, processing and connection to the SEM power-and-data bus, and a Sensor Interface Electronics (SIE) board that provides sensor interface needs and data path connection to the BIU.

  2. In vivo X-Ray excited optical luminescence from phosphor-doped aerogel and Sylgard 184 composites

    NASA Astrophysics Data System (ADS)

    Allison, Stephen W.; Baker, Ethan S.; Lynch, Kyle J.; Sabri, Firouzeh

    2017-06-01

    X-Ray excited optical luminescence (XEOL) is a new and noninvasive diagnostic technique suitable for in situ biochemical imaging and disease detection. The X-Ray excited optical luminescence of phosphor doping in crosslinked silica aerogel and Sylgard 184 hosts was investigated in this study. Composite silica aerogels and Sylgard 184 samples of 5%, 15%, and 50% concentrations by weight of La2O2S:Eu phosphor were prepared and inserted subcutaneously in a Sprague-Dawley rat and excited by X-Ray emission at 70 and 100 kV. A fiber optic bundle positioned within 5 mm of the sample collected the luminescence signal and conveyed it to a photomultiplier detector. The signal intensity scaled with dopant concentration. The time dependence of the predominantly red luminescence consisted of 60 cycle bursts of approximately 8 ms duration. The amplitude was modulated at about 10 Hz with a 60% depth. This indicates the time dependence of the X-Ray source. A simulation showed how to observe phosphor decay between individual burst pulses. The emission from the two types of composite samples was easily detected from the outside of the skin layer. Both Sylgard 184 and crosslinked silica aerogels are biocompatible and bio stable materials that could serve a variety of potential XEOL applications. These very strong signals imply potential for creating new In-vivo sensing applications and diagnostic tools.

  3. Noise impact of single-event upsets on an FPGA-based digital filter

    SciTech Connect

    Morgan, Keith S; Caffrey, Michael P; Graham, Paul S; Pratt, Brian H; Wirthlin, Michael J

    2009-01-01

    Field-programmable gate arrays are well-suited to DSP and digital communications applications. SRAM-based FPGAs, however, are susceptible to radiation-induced single-event upsets (SEUs) when deployed in space environments. These effects are often handled with the area and power-intensive TMR mitigation technique. This paper evaluates the effects of SEUs in the FPGA configuration memory as noise in a digital filter, showing that many SEUs in a digital communications system cause effects that could be considered noise rather than circuit failure. Since DSP and digital communications applications are designed to withstand certain types of noise, SEU mitigation techniques that are less costly than TMR may be applicable. This could result in large savings in area and power when implementing a reliable system. Our experiments show that, of the SEUs that affected the digital filter with a 20 dB SNR input signal, less than 14% caused an SNR loss of more than 1 dB at the output.

  4. Inner radiation belt source of helium and heavy hydrogen isotopes

    NASA Astrophysics Data System (ADS)

    Leonov, A. A.; Galper, A. M.; Koldashov, S. V.; Mikhailov, V. V.; Casolino, M.; Picozza, P.; Sparvoli, R.

    Nuclear interactions between inner zone protons and atoms in the upper atmosphere provide the main source of energetic H and He isotopes nuclei in the radiation belt. This paper reports on the specified calculations of these isotope intensities using various inner zone proton intensity models (AP-8 and SAMPEX/PET PSB97), the atmosphere drift-averaged composition and density model MSIS-90, and cross-sections of the interaction processes from the GNASH nuclear model code. To calculate drift-averaged densities and energy losses of secondaries, the particles were tracked in the geomagnetic field (modelled through IGRF-95) by integrating numerically the equation of the motion. The calculations take into account the kinematics of nuclear interactions along the whole trajectory of trapped proton. The comparison with new data obtained from the experiments on board RESURS-04 and MITA satellites and with data from SAMPEX and CRRES satellites taken during different phases of solar activity shows that the upper atmosphere is a sufficient source for inner zone helium and heavy hydrogen isotopes. The calculation results are energy spectra and angular distributions of light nuclear isotopes in the inner radiation belt that may be used to develop helium inner radiation belt model and to evaluate their contribution to SEU (single event upset) rates.

  5. The Appearance of the Medicean Moons in 17th Century Charts and Books—How Long Did It Take?

    NASA Astrophysics Data System (ADS)

    Mendillo, Michael

    2010-01-01

    Galileo's talents in perspective and chiaroscuro drawing led to his images of the Moon being accepted relatively quickly as the naturalistic portrayal of a truly physical place. In contrast to his resolved views of the Moon, Galileo saw the satellites of Jupiter as only points of light (as with stars). He thus used star symbols in Sidereus Nuncius (1610) for the moons, in constrast to an open disk for Jupiter. In this paper, I describe methods used in subsequent decades to portray objects that could not be seen in any detail but whose very existence challenged the scholastic approach to science. Within fifty years, the existence of the moons was such an accepted component of astronomy that they were depicted in the highly decorative “textbook” Atlas Coelestis seu Harmonia Macrocosmica by Andreas Cellarius (1660). Other symbolic methods, ranging from the routine to the dramatic, were used in subsequent centuries to portray the moons. Actual photographs using ground-based telescopes were not possible until the 20th century, just years before cameras on spaceflight missions captured the true details of the Medicean Stars.

  6. Efficient red phosphor double-perovskite Ca3WO6 with A-site substitution of Eu3+.

    PubMed

    Zhao, Xin; Wang, Jiajia; Fan, Li; Ding, Yufeng; Li, Zhaosheng; Yu, Tao; Zou, Zhigang

    2013-10-07

    Luminescent properties of Eu(3+) activated double perovskite structure Ca3WO6 were investigated. It emits an ideal red color centered at the wavelength of 618 nm with suitable excitation from f-f transitions of Eu(3+) ions (360-550 nm) matching the near ultraviolet and blue LEDs. Charge compensation effect of Li(+), Na(+), and K(+) was investigated, and K(+) proved to be the best. The co-doping ion K(+) has a great effect on the lattice distortion of the host matrix Ca3WO6, which facilitates the red emission of Eu(3+). The substitution site for Ca in Ca3WO6 was analyzed in detail by Raman spectra and calculation results. A-site substitution is responsible for the red emission of Eu(3+) activated Ca3WO6. The integrated emission intensity of optimal Ca3WO6:K(+),Eu(3+) excited at 395 nm is about 3.5 times greater than that of Y2O2S:Eu(3+) commercial phosphors, which makes it a promising red phosphor for white LEDs.

  7. [Cognitive, linguistic, motoric, and social deficits in schoolstarters with behavioral disorders].

    PubMed

    Korsch, Franziska; Petermann, Ulrike; Schmidt, Sören; Petermann, Franz

    2013-01-01

    Studies show that ADHD, conduct disorders, and anxiety disorders are clinical disorders mostly diagnosed in schoolstarters. The preschool medical examination in Bremen was therefore extended by behavioral screenings. Based on their screening results from the SEU (health examination for school entry) 2011 in Bremen, 67 preschoolers were tested for behavioral disorders. Subsequently, children with behavioral or emotional symptoms (N = 56) were compared to symptomfree controls (N = 52) for their cognitive, motoric, linguistic, and social-emotional development. Psychosocial health was obtained through external assessment by the parents and kindergarten teachers. Results of the WPPSI-III, M-ABC-2, and ET 6-6 were included in the analysis. 32 children met the criteria for behavioral disorders. Children with behavioral or emotional symptoms showed significant lower scores on tests measuring cognitive, motoric, linguistic and emotional development compared to controls. Results suggest that there is necessity to screen all preschoolers for behavioral disorders before entering school. Because children with clinical or subclinical behavioral disorders showed major developmental deficits compared to children without behavioral symptoms, it is essential to conduct a multiple assessment on children with suspected behavioral disorders to ensure early developmental support and adequate interventional programs.

  8. Detection efficiency and spatial resolution of the SIRAD ion electron emission microscope

    NASA Astrophysics Data System (ADS)

    Bisello, D.; Giubilato, P.; Kaminsky, A.; Mattiazzo, S.; Nigro, M.; Pantano, D.; Silvestrin, L.; Tessaro, M.; Wyss, J.; Bertazzoni, S.; Mongiardo, L.; Salmeri, M.; Salsano, A.

    2009-06-01

    An axial ion electron emission microscope (IEEM) has been built at the SIRAD irradiation facility at the 15 MV Tandem accelerator of INFN Legnaro National Laboratory (Padova, Italy) to obtain a micrometric sensitivity map to single event effects (SEE) of electronic devices. In this contribution we report on two experiments performed with the IEEM. Si 3N 4 ultra-thin membranes with a gold deposition were placed on the device under test (DUT) to ensure a uniform and abundant secondary electron emission In the first experiment we measured an IEEM ion detection efficiency of 83% with a 58Ni (220 MeV) beam, in good agreement with the expected value. The second experiment allowed us to estimate the lateral resolution of the IEEM. The positions of ion induced single event upsets (SEU) in a synchronous dynamic random access memory (SDRAM), used as a reference target, were compared with the corresponding ion impact points reconstructed by the IEEM. The result (FWHM ˜4.4 μm with a 79Br beam of 214 MeV) is encouraging because of the residual presence of distortions of the image and mechanical vibrations.

  9. REE radiation fault model: a tool for organizing and communication radiation test data and construction COTS based spacebourne computing systems

    NASA Technical Reports Server (NTRS)

    Ferraro, R.; Some, R.

    2002-01-01

    The growth in data rates of instruments on future NASA spacecraft continues to outstrip the improvement in communications bandwidth and processing capabilities of radiation-hardened computers. Sophisticated autonomous operations strategies will further increase the processing workload. Given the reductions in spacecraft size and available power, standard radiation hardened computing systems alone will not be able to address the requirements of future missions. The REE project was intended to overcome this obstacle by developing a COTS- based supercomputer suitable for use as a science and autonomy data processor in most space environments. This development required a detailed knowledge of system behavior in the presence of Single Event Effect (SEE) induced faults so that mitigation strategies could be designed to recover system level reliability while maintaining the COTS throughput advantage. The REE project has developed a suite of tools and a methodology for predicting SEU induced transient fault rates in a range of natural space environments from ground-based radiation testing of component parts. In this paper we provide an overview of this methodology and tool set with a concentration on the radiation fault model and its use in the REE system development methodology. Using test data reported elsewhere in this and other conferences, we predict upset rates for a particular COTS single board computer configuration in several space environments.

  10. Evaluation of commercial ADC radiation tolerance for accelerator experiments

    NASA Astrophysics Data System (ADS)

    Chen, K.; Chen, H.; Kierstead, J.; Takai, H.; Rescia, S.; Hu, X.; Xu, H.; Mead, J.; Lanni, F.; Minelli, M.

    2015-08-01

    Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detector front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on the development of a technique for testing analog to digital converters for radiation effects, in particular for single event effects. A total of seventeen commercial ADCs were evaluated for ionizing dose tolerance and extensive SEU measurements performed on a twelve and fourteen bit ADCs. Mitigation strategies for single event effects (SEE) are discussed for their use in the large hadron collider environment.

  11. On-orbit observations of single event upset in Harris HM-6508 1K RAMs, reissue A

    NASA Astrophysics Data System (ADS)

    Blake, J. B.; Mandel, R.

    1987-02-01

    The Harris HM-6508 1K x 1 RAMs are part of a subsystem of a satellite in a low, polar orbit. The memory module, used in the subsystem containing the RAMs, consists of three printed circuit cards, with each card containing eight 2K byte memory hybrids, for a total of 48K bytes. Each memory hybrid contains 16 HM-6508 RAM chips. On a regular basis all but 256 bytes of the 48K bytes are examined for bit errors. Two different techniques were used for detecting bit errors. The first technique, a memory check sum, was capable of automatically detecting all single bit and some double bit errors which occurred within a page of memory. A memory page consists of 256 bytes. Memory check sum tests are performed approximately every 90 minutes. To detect a multiple error or to determine the exact location of the bit error within the page the entire contents of the memory is dumped and compared to the load file. Memory dumps are normally performed once a month, or immediately after the check sum routine detects an error. Once the exact location of the error is found, the correct value is reloaded into memory. After the memory is reloaded, the contents of the memory location in question is verified in order to determine if the error was a soft error generated by an SEU or a hard error generated by a part failure or cosmic-ray induced latchup.

  12. Time resolved ion beam induced charge collection

    SciTech Connect

    SEXTON,FREDERICK W.; WALSH,DAVID S.; DOYLE,BARNEY L.; DODD,PAUL E.

    2000-04-01

    Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a {minus}.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients.

  13. The advances and new technologies for the study of mitochondrial diseases.

    PubMed

    Bianco, Bianca; Montagna, Erik

    2016-01-01

    ABSTRACTGenetic mitochondrial disorders are responsible for the most common inborn errors of metabolism, caused by mutations in either nuclear genes or in mitochondrial DNA. This article presents the prokaryotic origin of the organelle and the relation between nuclear and mitochondrial genomes, as well as current evolutionary models for such mechanisms. It also addresses the structure of mitochondrial genes, their expression pattern, clinical features of gene defects, risk of transmission and current techniques to avoid these events in assisted human reproduction. Finally, it discusses the ethical implications of these possibilities.RESUMOAs doenças genéticas mitocondriais são responsáveis pelos erros inatos do metabolismo mais comuns, causados por mutações tanto em genes nucleares como no DNA mitocondrial. Este artigo apresenta a origem procariótica dessa organela, e a relação entre os genomas nuclear e mitocondrial, bem como modelos evolutivos correntes para esses mecanismos. Também trata da estrutura dos genes mitocondriais, seu padrão de expressão, características clínicas de defeitos genéticos, riscos de transmissão e técnicas atualmente utilizadas para evitar esses eventos em reprodução humana assistida. Finalmente, discute as implicações éticas dessas possibilidades.

  14. Investigation of multilayer domains in large-scale CVD monolayer graphene by optical imaging

    NASA Astrophysics Data System (ADS)

    Yu, Yuanfang; Li, Zhenzhen; Wang, Wenhui; Guo, Xitao; Jiang, Jie; Nan, Haiyan; Ni, Zhenhua

    2017-03-01

    CVD graphene is a promising candidate for optoelectronic applications due to its high quality and high yield. However, multi-layer domains could inevitably form at the nucleation centers during the growth. Here, we propose an optical imaging technique to precisely identify the multilayer domains and also the ratio of their coverage in large-scale CVD monolayer graphene. We have also shown that the stacking disorder in twisted bilayer graphene as well as the impurities on the graphene surface could be distinguished by optical imaging. Finally, we investigated the effects of bilayer domains on the optical and electrical properties of CVD graphene, and found that the carrier mobility of CVD graphene is seriously limited by scattering from bilayer domains. Our results could be useful for guiding future optoelectronic applications of large-scale CVD graphene. Project supported by the National Natural Science Foundation of China (Nos. 61422503, 61376104), the Open Research Funds of Key Laboratory of MEMS of Ministry of Education (SEU, China), and the Fundamental Research Funds for the Central Universities.

  15. Formation Control of the MAXIM L2 Libration Orbit Mission

    NASA Technical Reports Server (NTRS)

    Folta, David; Hartman, Kate; Howell, Kathleen; Marchand, Belinda

    2004-01-01

    The Micro-Arcsecond Imaging Mission (MAXIM), a proposed concept for the Structure and Evolution of the Universe (SEU) Black Hole Imaging mission, is designed to make a ten million-fold improvement in X-ray image clarity of celestial objects by providing better than 0.1 microarcsecond imaging. To achieve mission requirements, MAXIM will have to improve on pointing by orders of magnitude. This pointing requirement impacts the control and design of the formation. Currently the architecture is comprised of 25 spacecraft, which will form the sparse apertures of a grazing incidence X-ray interferometer covering the 0.3-10 keV bandpass. This configuration will deploy 24 spacecraft as optics modules and one as the detector. The formation must allow for long duration continuous science observations and also for reconfiguration that permits re-pointing of the formation. In this paper, we provide analysis and trades of several control efforts that are dependent upon the pointing requirements and the configuration and dimensions of the MAXIM formation. We emphasize the utilization of natural motions in the Lagrangian regions that minimize the control efforts and we address both continuous and discrete control via LQR and feedback linearization. Results provide control cost, configuration options, and capabilities as guidelines for the development of this complex mission.

  16. Single event phenomena in atmospheric neutron environments

    SciTech Connect

    Gossett, C.A.; Hughlock, B.W.; Katoozi, M.; LaRue, G.S. ); Wender, S.A. )

    1993-12-01

    As integrated circuit technology achieves higher density through smaller feature sizes and as the airplane manufacturing industry integrates more sophisticated electronic components into the design of new aircraft, it has become increasingly important to evaluate the contribution of single event effects, primarily Single Event Upset (SEU), to the safety and reliability of commercial aircraft. In contrast to the effects of radiation on electronic systems in space applications for which protons and heavy ions are of major concern, in commercial aircraft applications the interactions of high energy neutrons are the dominant cause of single event effects. These high energy neutrons are produced by the interaction of solar and galactic cosmic rays, principally protons and heavy ions, in the upper atmosphere. This paper will describe direct experimental measurements of neutron-induced Single Event Effect (SEE) rates in commercial high density static random access memories in a neutron environment characteristic of that at commercial airplane altitudes. The first experimental measurements testing current models for neutron-silicon burst generation rates will be presented, as well as measurements of charge collection in silicon test structures as a function of neutron energy. These are the first laboratory SEE and charge collection measurements using a particle beam having a continuum energy spectrum and with a shape nearly identical to that observed during flight.

  17. [Enterobius vermicularis in preschool children from a suburban area in San Félix, Bolívar State, Venezuela].

    PubMed

    Requena, Ixora; Jiménez, Yolimar; Rodríguez, Natacha; Sandoval, Maria; Alcala, Frannegy; Blanco, Ytalia; Devera, Rodolfo

    2007-09-01

    To determine the enterobiosis prevalence in preschool children, a study was carried out from may-july 2003, in the SEU "Teresa de la Parra" in San Félix, Bolívar State, Venezuela. Three samples from the perianal region were obtained from every child, by applying the Graham method, and one sample was obtained of the subungucal deposit by scraping and cutting off their finger nails. These samples were preserved in 10% formol and processed by the formol-ether method. Also, a stool sample was collected and analyzed by direct examination and the formol-ether method. The prevalence of Enterobius vermicularis was 45.8% (27/59). No differences in relation to age (chi2 = 1.23 d. f. = 2) and sex (p > 0.05) were observed between the infected children. The eggs E. vermicularis were not observed in the 59 samples of subungueal deposits. In conclusion, although the enterobiosis prevalence was high, as determined by the Graham method, a relationship could not be found between E. vermicularis in the scotch tape and the finger nail samples of the children evaluated.

  18. A series of color tunable yellow-orange-red-emitting SrWO4:RE (Sm3+, Eu3+-Sm3+) phosphor for near ultraviolet and blue light-based warm white light emitting diodes

    NASA Astrophysics Data System (ADS)

    Ren, Yandong; Liu, Yonghao; Yang, Rui

    2016-03-01

    A series of wide-range-tunable light emissive SrWO4:Sm3+, SrWO4:Sm3+,Eu3+ phosphors were synthesized via the simple co-precipitation method. The charge compensation can greatly improve SrWO4: Sm3+ phosphors luminous intensity. The critical distance, ηT and energy transfer mechanism of SrWO4:0.01Sm3+,0.12Eu3+ were studied. These obtained phosphors exhibit a high luminous efficiency, purity and lower color temperature of the comfortable warm white LEDs. Hues varying have been generated by appropriately tuning the Sm3+ ions concentration, excitation wavelength or Sm3+, Eu3+ co-doping, which have the color tunable wide gamut light covering the yellow-green, greenish-yellow, yellow, yellow orange, orange, reddish orange and red chromaticity region. In particular, SrWO4:0.01Sm3+,0.12Eu3+ phosphors excited at 404 and 480 nm have higher color saturation than commercially available Y2O2S:Eu3+ red phosphor. These phosphors can be excited efficiently using commercial ultraviolet, blue laser diodes and LEDs, and can be used for developing new color light sources, fluorescent display devices, ultraviolet-sensors and tunable visible lasers.

  19. Estudo de cavidade reentrante supercondutora a ser utilizada nos transdutores paramétricos do detector brasileiro de ondas gravitacionais Mario Schenberg

    NASA Astrophysics Data System (ADS)

    Ribeiro, K. L.; Furtado, S. R.; Aguiar, O. D.; Frajuca, C.

    2003-08-01

    Cavidades reentrantes de nióbio vêm sendo utilizadas pelo grupo Australiano nos transdutores eletromecânicos paramétricos do detector de ondas gravitacionais Niobè. Esses transdutores paramétricos são ativados por um sinal AC na faixa de microondas (banda X), que é modulado pelo sinal mecânico da vibração da antena esférica, com a variação de um parâmetro, que, no caso, é a capacitância da cavidade. Nós estudamos esse tipo de cavidade, com o objetivo de transformá-la de reentrante aberta para reentrante fechada, de forma a utilizá-la nos transdutores paramétricos do detector brasileiro Mario Schenberg. O desempenho do transdutor depende de alguns parâmetros da cavidade, como a sua Figura de Mérito (Q elétrico) e o seu acoplamento elétrico com o circuito externo. Neste trabalho mostramos a medida do Q elétrico como função do acoplamento, do acabamento superficial interno e do vazamento de microondas da cavidade, e mostramos o desempenho esperado para o detector Mario Schenberg usando uma cavidade supercondutora reentrante fechada de nióbio.

  20. An on-line expert system for diagnosing environmentally induced spacecraft anomalies using CLIPS

    NASA Technical Reports Server (NTRS)

    Lauriente, Michael; Rolincik, Mark; Koons, Harry C; Gorney, David

    1993-01-01

    A new rule-based, expert system for diagnosing spacecraft anomalies is under development. The knowledge base consists of over two-hundred rules and provide links to historical and environmental databases. Environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. The use of heuristics frees the user from searching through large amounts of irrelevant information (varying degrees of confidence in an answer) or 'unknown' to any question. The expert system not only provides scientists with needed risk analysis and confidence estimates not available in standard numerical models or databases, but it is also an effective learning tool. In addition, the architecture of the expert system allows easy additions to the knowledge base and the database. For example, new frames concerning orbital debris and ionospheric scintillation are being considered. The system currently runs on a MicroVAX and uses the C Language Integrated Production System (CLIPS).

  1. A Re-programmable Platform for Dynamic Burn-in Test of Xilinx Virtexll 3000 FPGA for Military and Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Roosta, Ramin; Wang, Xinchen; Sadigursky, Michael; Tracton, Phil

    2004-01-01

    Field Programmable Gate Arrays (FPGA) have played increasingly important roles in military and aerospace applications. Xilinx SRAM-based FPGAs have been extensively used in commercial applications. They have been used less frequently in space flight applications due to their susceptibility to single-event upsets. Reliability of these devices in space applications is a concern that has not been addressed. The objective of this project is to design a fully programmable hardware/software platform that allows (but is not limited to) comprehensive static/dynamic burn-in test of Virtex-II 3000 FPGAs, at speed test and SEU test. Conventional methods test very few discrete AC parameters (primarily switching) of a given integrated circuit. This approach will test any possible configuration of the FPGA and any associated performance parameters. It allows complete or partial re-programming of the FPGA and verification of the program by using read back followed by dynamic test. Designers have full control over which functional elements of the FPGA to stress. They can completely simulate all possible types of configurations/functions. Another benefit of this platform is that it allows collecting information on elevation of the junction temperature as a function of gate utilization, operating frequency and functionality. A software tool has been implemented to demonstrate the various features of the system. The software consists of three major parts: the parallel interface driver, main system procedure and a graphical user interface (GUI).

  2. Virtex-II Pro SEE Test Methods and Results

    NASA Technical Reports Server (NTRS)

    Petrick, David; Powell, Wesley; Howard, James

    2004-01-01

    The Xilinx Virtex-II Pro is a platform FPGA that embeds multiple microprocessors within the fabric of an SRAM-based reprogrammable FPGA. The variety and quantity of resources provided by this family of devices make them very attractive for spaceflight applications. However, these devices will be susceptible to single event effects (SEE), which must be mitigated. To use the Virtex-II Pro reliably in space applications, these devices must first be tested to determine if they are susceptible to single event latchup (SEL), the degree to which they are susceptible to single event upsets (SEU) and single event transients (SET), and how these effects are manifested in the device. With this information, mitigations schemes can be developed and tested that address the specific susceptiblities of these devices. This initial SEE test uses a commercial off the shelf Virtex-II Pro evaluation board, with a single processor XC2VP7 FPGA. The FPGA on this board is an acid etched device, which can be partially covered with a shield. The shield covers a portion of the logic, routing, and memory resources along with some of the RocketIO transceivers. The processor, along with a large portion of logic, routing, memory, and transceivers are left exposed. This test will be performed at the Cyclotron Laboratories at Texas A&M University and Michigan State University using ions of varying energy levels and fluencies.

  3. Ion Beam Induced Charge Collection (IBICC) Studies of Integrated Circuits Using a 10MeV Carbon Microbeam

    SciTech Connect

    Aton, T.J.; Bouanani, M. E.; Doyle, B.L.; Duggan, J.L.; Guo, B.N.; McDaniel, F.D.; Renfrow, S.N.; Walsh, D.S.

    1998-09-29

    As feature sizes of Integrated Circuits (ICs) continue to shrinlL the sensitivity of these devices, particularly SRAMS and DR4Ms, to natural radiation is increasing. The radiation can lead to the uncontrolled deposition of charge within an IC, which ean alter, for example, the memoty state of a bit and thereby produce what is edled a `SOW error, or Single Event Upset (SEU). The response of ICS to natural background radiation is therefore of great coneem regarding the reliability of Mure devices. In this paper, we present results where Ion Beam Induced Charge Collection (TBICC) technique was used to simulate neutron-induced Si recoil dlkcts in IC test structures. The present wo~ wnducted at the San& National Laboratories, uses a 10 MeV Carbon mierobeam with 1 pm spot to scan test structures on specifically designed ICS. The test structure contains junctions typical of S RAMS and DRAMs. Charge is eolleeted from different areas of the IC under various conditions of junction back bias. The data are digitized and displayed as 3D images combined with KY) coordination. With the aid of IC layout informatio~ the 3D images are sepamted into difTerent layers to allow the identification of charge collection etlciency in the test structures. An analysis of the charge collection efficiency from dillerent test areas is given.

  4. Two common structural motifs for TCR recognition by staphylococcal enterotoxins

    PubMed Central

    Rödström, Karin E. J.; Regenthal, Paulina; Bahl, Christopher; Ford, Alex; Baker, David; Lindkvist-Petersson, Karin

    2016-01-01

    Superantigens are toxins produced by Staphylococcus aureus, called staphylococcal enterotoxins (abbreviated SEA to SEU). They can cross-link the T cell receptor (TCR) and major histocompatibility complex class II, triggering a massive T cell activation and hence disease. Due to high stability and toxicity, superantigens are potential agents of bioterrorism. Hence, antagonists may not only be useful in the treatment of disease but also serve as countermeasures to biological warfare. Of particular interest are inhibitors against SEA and SEB. SEA is the main cause of food poisoning, while SEB is a common toxin manufactured as a biological weapon. Here, we present the crystal structures of SEA in complex with TCR and SEE in complex with the same TCR, complemented with computational alanine-scanning mutagenesis of SEA, SEB, SEC3, SEE, and SEH. We have identified two common areas that contribute to the general TCR binding for these superantigens. This paves the way for design of single antagonists directed towards multiple toxins. PMID:27180909

  5. Report on final recommendations for IMPS engineering-science payload

    NASA Technical Reports Server (NTRS)

    Garrett, H. B.

    1984-01-01

    Six general categories of key scientific and engineering concerns for the interactions measurements payload for shuttle (IMPS) mission are addressed: (1) dielectric charging; (2) material property changes; (3) electromagnetic interference, plasma interactions, and plasma wake effects associated with high-voltage solar arrays and large space structures; (4) radio frequency distortion and nonlinearities due to the enhanced plasma in the shuttle ram/wake; (5) shuttle glow and contamination; and (6) plasma interactions with the space-based radar. Lesser concerns are the interactions associated with EVA; the radiation and SEU effects peculiar to the auroral/polar cap environments; and space debris. The measurements needed to address the concerns associated with the general categories are described and a list of generic investigations capable of making the required measurements, emphasizing the spectrum of measurements necessary to quantize the interactions in the auroral/polar environments are included. A suggested ground-test plan for the IMPS project, a description of proposed follow-on IMPS missions, and a detailed bibliography for each of the interactions discussed are included.

  6. SPi User Manual V0.1

    SciTech Connect

    Trimpl, M.; Yarema, R.; Newcomer, M.; Dressnandt, N.; Villani, G.; Weber, M.; Holt, R.; /Rutherford

    2011-05-01

    This document describes the Serial Powering Interface (SPi) ASIC. SPi is a general purpose ASIC prototype designed for use in serial powering of silicon detector instrumentation. This description is written as a user manual to aid application, not as a design description. SPi is a generic custom ASIC, manufactured in 0.25 {mu}m CMOS by TSMC, to interface between a constant current source and silicon detector read-out chips. There is no SEU (single event upset) protection, but most (not all) components are radiation tolerant design. An operating voltage of 1.2 to 2.5 volts and other design features make the IC suitable for a variety of serial powering architectures and ROICs. It should be noted that the device is likely to be a prototype for demonstration rather than a product for inclusion in a detector. The next design(s), SPin, are likely to be designed for a specific application (eg SLHC). The component includes: (1) Seven bi-directional LVDS-like buffers for high data rate links to/from the read-out chips. These are AC coupled (series capacitor) off-chip for DC level conversion; (2) A programmable internal programmable shunt regulator to provide a defined voltage to readout chips when linked in a serial powering chain; (3) A programmable internal shunt regulator control circuit for external transistor control; (4) Shunt current measurement (for internal shunt regulator); (5) A programmable internal shunt regulator current alarm; and (6) Two programmable linear regulators.

  7. Reliability of small geometry VLSI devices for microelectronics

    NASA Astrophysics Data System (ADS)

    White, Marvin H.

    1992-02-01

    This proposal is a continuation of a project which began in August 1986. The goal of the project, in a broad sense, is to perform exploratory research into the physics of carriers in silicon inversion layers with a focus on the issues which affect the reliability of small geometry VLSI devices. This project permits us to study the physical electronics of silicon surfaces and the overlying insulators. In the proposed project we stress the application of this research to the area of Wafer Scale Integration where reliability and fault tolerance are key issues for the SDI program. The extensive signal processing and data storage required to implement high-resolution, sensor-based systems demands that consideration be given to the area of system and component reliability. At the component level the issues revolve around the reliability of the scaled MOS Transistor with nanometric feature sizes. One important area is the susceptibility of the gate insulator to (1) hot electron trapping, (2) premature dielectric breakdown, and (3) space radiation environment considerations which can limit the MTTF of the SDIO mission. A second issue at the component level is the SDI need for low-power, high-density, nonvolatile data storage with nondestructive readout (NDRO), radiation tolerance and immunity to single event upsets (SEU's).

  8. A Radiation-Hardened Design Flow for Advanced SoC

    NASA Astrophysics Data System (ADS)

    Liran, Tuvia; Ginosar, Ran; Alon, Dov

    2010-08-01

    The technology and design flow used for developing two advanced Systems On Chip is described. The chips are JPIC, an image compression ASIC using JPEG2000 standard, and GR712RC, a dual core LEON3FT processor. Both chips employ the Rad-Hard-By-Design RadSafe™ technology, and are implemented on a standard 0.18μm CMOS technology. Each chip size is 12x12mm, integrating more than 40 million transistors. RadSafe™ technology provides very high immunity to all radiation effects. The library was designed for high immunity to radiation and high reliability. It includes standard cells, SRAMs, all-digital DLL and I/O cells. It was proven on several test chips, demonstrating TID immunity in excess of 300Krad, proven SEL above 80MeV and SEU at 20μ2 cross section (10-12 errors/bit/day). Logic design includes EDAC, memory BIST, and techniques to minimize soft errors. Logic synthesis was performed with large timing margins and scan insertion. Physical synthesis includes a robust power grid, careful placement of I/O cells, immunity to process sensitivities, robustness to thermomechanical stress and packaging reliability. A custom 240 pins CQFP ceramic package for GR712RC was optimized for mechanical stress, hermeticity, improved supply connection for reduced impedance, and robustness to handling. A custom 208 pins PQFP plastic package was designed for JPIC.

  9. An Analytical Overview of Spirituality in NANDA-I Taxonomies.

    PubMed

    Mesquita, Ana Cláudia; Caldeira, Sílvia; Chaves, Erika; Carvalho, Emilia Campos de

    2017-03-01

    To discuss the approach of spirituality in NANDA-I taxonomies, based on the elements that characterize this phenomenon. This study was based on concepts that are usually adopted in the literature for defining spirituality and on the analysis of the NANDA-I taxonomies from I to III. Spirituality is included in all taxonomies but all three are missing some attributes to guarantee the completeness of this dimension for nursing diagnosis. Taxonomy III makes different approaches to spirituality and some inconsistencies. Contribute to the development and review of the new proposal for taxonomy. Discutir a abordagem à espiritualidade nas taxonomias da NANDA-I, baseada nos elementos que caracterizam este fenômeno. MÉTODOS: Este estudo foi baseado em conceitos usualmente adotados na literatura de enfermagem para definir espiritualidade e na análise das taxonomias da NANDA-I, desde a I à III. A espiritualidade está incluída nas taxonomias, porém estas carecem de atributos do seu conceito. CONCLUSÕES: A taxonomia III faz diferentes abordagens à espiritualidade, porém com algumas inconsistências identificadas. IMPLICAÇÕES PARA A ENFERMAGEM: Esta análise pode contribuir para o desenvolvimento e revisão da taxonomia III. © 2017 NANDA International, Inc.

  10. Bimolecular fluorescence complementation (BiFC) assay for protein-protein interaction in onion cells using the helios gene gun.

    PubMed

    Hollender, Courtney A; Liu, Zhongchi

    2010-06-12

    Investigation of gene function in diverse organisms relies on knowledge of how the gene products interact with each other in their normal cellular environment. The Bimolecular Fluorescence Complementation (BiFC) Assay(1) allows researchers to visualize protein-protein interactions in living cells and has become an essential research tool. This assay is based on the facilitated association of two fragments of a fluorescent protein (GFP) that are each fused to a potential interacting protein partner. The interaction of the two protein partners would facilitate the association of the N-terminal and C-terminal fragment of GFP, leading to fluorescence. For plant researchers, onion epidermal cells are an ideal experimental system for conducting the BiFC assay because of the ease in obtaining and preparing onion tissues and the direct visualization of fluorescence with minimal background fluorescence. The Helios Gene Gun (BioRad) is commonly used for bombarding plasmid DNA into onion cells. We demonstrate the use of Helios Gene Gun to introduce plasmid constructs for two interacting Arabidopsis thaliana transcription factors, SEUSS (SEU) and LEUNIG HOMOLOG (LUH)(2) and the visualization of their interactions mediated by BiFC in onion epidermal cells.

  11. Virtex-II Pro SEE Test Methods and Results

    NASA Technical Reports Server (NTRS)

    Petrick, David; Powell, Wesley; Howard, James W., Jr.; LaBel, Kenneth A.

    2004-01-01

    The objective of this coarse Single Event Effect (SEE) test is to determine the suitability of the commercial Virtex-II Pro family for use in spaceflight applications. To this end, this test is primarily intended to determine any Singe Event Latchup (SEL) susceptibilities for these devices. Secondly, this test is intended to measure the level of Single Event Upset (SEU) susceptibilities and in a general sense where they occur. The coarse SEE test was performed on a commercial XC2VP7 device, a relatively small single processor version of the Virtex-II Pro. As the XC2VP7 shares the same functional block design and fabrication process with the larger Virtex-II Pro devices, the results of this test should also be applicable to the larger devices. The XC2VP7 device was tested on a commercial Virtex-II Pro development board. The testing was performed at the Cyclotron laboratories at Texas A&M and Michigan State Universities using ions of varying energy levels and fluences.

  12. Fluorescence excitation and propagation through brain phantom gelatins: measurements and potential applications

    SciTech Connect

    Allison, Stephen W; Gillies, George

    2010-01-01

    We have investigated the utility of 0.6% agarose gels as surrogate materials for brain tissues in optical propagation studies for possible diagnostic and therapeutic applications. Centimeter-scale layers of the gel exhibited a Beer's law attenuation factor, , of 0.2 mm 1 for incident illumination via a pulsed LED (100 Hz) at 405 nm. This result was different by only about a factor of 3 from the effective penetration depth at similar wavelengths through in vitro samples of the gray (cortical) matter of human brain, as measured by others. Then, films of the thermographic phosphors La2O2S:Eu, Mg4FGeO6:Mn, YAG:Cr and variants of the latter were formed on aluminum substrates and the fluorescence of these samples was stimulated and observed through layers of the gel up to 4 cm thick. In all cases, the fluorescence was easily excited and distinguishable above the background. The results demonstrate that this gel might serve as an inexpensive and robust test bed for exploratory studies of neurological modalities involving propagation of optical signals within brain tissues.

  13. Compendium of Single Event Effects, Total Ionizing Dose, and Displacement Damage for Candidate Spacecraft Electronics for NASA

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; OBryan, Martha V.; Chen, Dakai; Campola, Michael J.; Casey, Megan C.; Pellish, Jonathan A.; Lauenstein, Jean-Marie; Wilcox, Edward P.; Topper, Alyson D.; Ladbury, Raymond L.; Berg, Melanie D.; Gigliuto, Robert A.; Boutte, Alvin J.; Cochran, Donna J.; Buchner, Stephen P.; Violette, Daniel P.

    2014-01-01

    We present results and analysis investigating the effects of radiation on a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects (SEE), proton-induced displacement damage (DD), and total ionizing dose (TID). Introduction: This paper is a summary of test results.NASA spacecraft are subjected to a harsh space environment that includes exposure to various types of ionizing radiation. The performance of electronic devices in a space radiation environment is often limited by its susceptibility to single event effects (SEE), total ionizing dose (TID), and displacement damage (DD). Ground-based testing is used to evaluate candidate spacecraft electronics to determine risk to spaceflight applications. Interpreting the results of radiation testing of complex devices is quite difficult. Given the rapidly changing nature of technology, radiation test data are most often application-specific and adequate understanding of the test conditions is critical. Studies discussed herein were undertaken to establish the application-specific sensitivities of candidate spacecraft and emerging electronic devices to single-event upset (SEU), single-event latchup (SEL), single-event gate rupture (SEGR), single-event burnout (SEB), single-event transient (SET), TID, enhanced low dose rate sensitivity (ELDRS), and DD effects.

  14. An Intelligent computer-aided tutoring system for diagnosing anomalies of spacecraft in operation

    NASA Technical Reports Server (NTRS)

    Rolincik, Mark; Lauriente, Michael; Koons, Harry C.; Gorney, David

    1993-01-01

    A new rule-based, expert system for diagnosing spacecraft anomalies is under development. The knowledge base consists of over two-hundred (200) rules and provides links to historical and environmental databases. Environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. When the user selects the novice mode, the system automatically gives detailed explanations and descriptions of terms and reasoning as the session progresses, in a sense teaching the user. As such it is an effective tutoring tool. The use of heuristics frees the user from searching through large amounts of irrelevant information and allows the user to input partial information (varying degrees of confidence in an answer) or 'unknown' to any question. The system is available on-line and uses C Language Integrated Production System (CLIPS), an expert shell developed by the NASA Johnson Space Center AI Laboratory in Houston.

  15. Diagnosing anomalies of spacecraft for space maintenance and servicing

    NASA Technical Reports Server (NTRS)

    Lauriente, Michael; Rolincik, Mark; Koons, Harry C.; Gorney, David

    1994-01-01

    Very often servicing of satellites is necessary to replace components which are responsible for anomalous behavior of satellite operations due to adverse interactions with the natural space environment. A major difficulty with this diagnosis is that those responsible for diagnosing these anomalies do not have the tools to assess the role of the space environment causing the anomaly. To address this issue, we have under development a new rule-based, expert system for diagnosing spacecraft anomalies. The knowledge base consists of over two-hundred rules and provides links to historical and environmental databases. Environmental causes considered are bulk charging, single event upsets (SEU), surface charging, and total radiation dose. The system's driver translates forward chaining rules into a backward chaining sequence, prompting the user for information pertinent to the causes considered. When the user selects the novice mode, the system automatically gives detailed explanations and descriptions of terms and reasoning as the session progresses, in a sense teaching the user. As such it is an effective tutoring tool. The use of heuristics frees the user from searching through large amounts of irrelevant information and allows the user to input partial information (varying degrees of confidence in an answer) or 'unknown' to any question. The system is available on-line and uses C Language Integrated Production System (CLIPS), an expert shell developed by the NASA Johnson Space Center AI Laboratory in Houston.

  16. Use of SX Series Devices and IEEE 1149.1 JTAG Circuitry

    NASA Technical Reports Server (NTRS)

    Katz, Richard B.; Wang, J. J.

    1998-01-01

    This report summarizes the use of SX series devices and their JTAG 1149.1 circuitry. 'JTAG' circuitry was originally designed to standardize testing of boards via a simple control port interface electrically without having to use devices such as a bed of nails tester. JTAG is also used for other functions such as executing built-in-test sequences, identifying devices, or, through custom instructions, other functions designed in by the chip designer. The JTAG circuitry is designed for test only; it has no functional use in the integrated circuit during normal operations. The JTAG circuitry and the mode of the device is controlled by a circuit block known as the 'TAP controller,' which is a sixteen-state state machine along with various registers. The controller is normally in an operational state known as TEST-LOGIC-RESET. In this state, the device is held in a fully functional, operational mode. However, a Single Event Upset (SEU) may remove the TAP controller from this state, causing a loss of control of the integrated circuit, unless certain precautions are taken, such as grounding the optional JTAG TRST signal.

  17. REE radiation fault model: a tool for organizing and communication radiation test data and construction COTS based spacebourne computing systems

    NASA Technical Reports Server (NTRS)

    Ferraro, R.; Some, R.

    2002-01-01

    The growth in data rates of instruments on future NASA spacecraft continues to outstrip the improvement in communications bandwidth and processing capabilities of radiation-hardened computers. Sophisticated autonomous operations strategies will further increase the processing workload. Given the reductions in spacecraft size and available power, standard radiation hardened computing systems alone will not be able to address the requirements of future missions. The REE project was intended to overcome this obstacle by developing a COTS- based supercomputer suitable for use as a science and autonomy data processor in most space environments. This development required a detailed knowledge of system behavior in the presence of Single Event Effect (SEE) induced faults so that mitigation strategies could be designed to recover system level reliability while maintaining the COTS throughput advantage. The REE project has developed a suite of tools and a methodology for predicting SEU induced transient fault rates in a range of natural space environments from ground-based radiation testing of component parts. In this paper we provide an overview of this methodology and tool set with a concentration on the radiation fault model and its use in the REE system development methodology. Using test data reported elsewhere in this and other conferences, we predict upset rates for a particular COTS single board computer configuration in several space environments.

  18. Use of SX Series Devices and IEEE 1149.1 JTAG Circuitry. Revised

    NASA Technical Reports Server (NTRS)

    Katz, Richard B.; Wang, J. J.

    1998-01-01

    This report summarizes the use of SX series devices and their JTAG 1149.1 circuitry. 'JTAG' circuitry was originally designed to standardize testing of boards via a simple control port interface electrically without having to use devices such as a bed of nails tester. JTAG is also used for other functions such as executing built-in-test sequences, identifying devices, or, through custom instructions, other functions designed in by the chip designer. The JTAG circuitry is designed for test only; it has no functional use in the integrated circuit during normal operations. The JTAG circuitry and the mode of the device is controlled by a circuit block known as the 'TAP controller,' which is a sixteen-state state machine along with various registers. The controller is normally in an operational state known as TEST-LOGIC-RESET. In this state, the device is held in a fully functional, operating mode. However, a Single Event Upset (SEU) may remove the TAP controller from this state, causing a loss of control of the integrated circuit, unless certain precautions are taken, such as grounding the optional JTAG TRST signal.

  19. A 130 nm ASIC prototype for the NA62 Gigatracker readout

    NASA Astrophysics Data System (ADS)

    Dellacasa, G.; Garbolino, S.; Marchetto, F.; Martoiu, S.; Mazza, G.; Rivetti, A.; Wheadon, R.

    2011-09-01

    One of the most challenging detectors of the NA62 experiment is the silicon tracker, called Gigatracker. It consists of three hybrid silicon pixel stations, each one covering an area of 27 mm×60 mm. While the maximum pixel size is fairly large, 300 μm×300 μm the system has to sustain a very high particle rate, 1.5 MHz/mm 2, which corresponds to 800 MHz for each station. To obtain an efficient tracking with such a high rate the required track timing resolution is 150 ps (rms). Therefore the front-end ASIC should provide for each pixel a 200 ps time measurement capability, thus leading to the requirement of time walk compensation and very compact TDCs. Moreover, Single Event Upset protection has to be implemented in order to protect the digital circuitry. An ASIC prototype has been realized in CMOS 130 nm technology, containing three pixel columns. The chip performs the time walk compensation by a Constant Fraction Discriminator circuit, while the time measurement is performed by a Time to Amplitude Converter based TDC, both of them implemented on each pixel cell. The End of Column circuit containing only digital logic is responsible for the data readout from the pixel cell. The whole chip works with a system clock of 160 MHz and the digital logic is SEU protected by the use of Hamming codes. The detailed architecture of the ASIC prototype and test results are presented.

  20. Design considerations for a radiation hardened nonvolatile memory

    SciTech Connect

    Murray, J.R.

    1993-02-01

    The SA3823 64K EEPROM was developed for both weapon and space applications. The circuit was designed for fabrication in a CMOS/SNOS (Complementary Metal Oxide Semiconductor/Silicon Nitride Oxide Semiconductor) process since this process offers maximum radiation hardness for nonvolatile circuits. [1--6] Specific aspects of the circuit design were influenced by each of the radiation environments of concern. Total dose radiation effects were a factor in the memory cell and sense amplifier designs. Power distribution to the various latches was designed to tolerate the photocurrents generated during a transient radiation pulse. Single event upset (SEU) concerns were accounted for in the design of the latches and the control logic. The SA3823 is a 8K x 8 bit EEPROM which is partitioned into 128 pages with 64 bytes in each page. Data is programmed into the memory one page at a time. Writing data into the memory is a two step process: loading 64 bytes into the data-in latches and then programming the latched data into a page of the memory.

  1. Design considerations for a radiation hardened nonvolatile memory

    SciTech Connect

    Murray, J.R.

    1993-01-01

    The SA3823 64K EEPROM was developed for both weapon and space applications. The circuit was designed for fabrication in a CMOS/SNOS (Complementary Metal Oxide Semiconductor/Silicon Nitride Oxide Semiconductor) process since this process offers maximum radiation hardness for nonvolatile circuits. [1--6] Specific aspects of the circuit design were influenced by each of the radiation environments of concern. Total dose radiation effects were a factor in the memory cell and sense amplifier designs. Power distribution to the various latches was designed to tolerate the photocurrents generated during a transient radiation pulse. Single event upset (SEU) concerns were accounted for in the design of the latches and the control logic. The SA3823 is a 8K x 8 bit EEPROM which is partitioned into 128 pages with 64 bytes in each page. Data is programmed into the memory one page at a time. Writing data into the memory is a two step process: loading 64 bytes into the data-in latches and then programming the latched data into a page of the memory.

  2. Enhanced photosynthetic activity in Spinacia oleracea by spectral modification with a photoluminescent light converting material.

    PubMed

    Xia, Qi; Batentschuk, Miroslaw; Osvet, Andres; Richter, Peter; Häder, Donat P; Schneider, Juergen; Brabec, Christoph J; Wondraczek, Lothar; Winnacker, Albrecht

    2013-11-04

    The spectral conversion of incident sunlight by appropriate photoluminescent materials has been a widely studied issue for improving the efficiency of photovoltaic solar energy harvesting. By using phosphors with suitable excitation/emission properties, also the light conditions for plants can be adjusted to match the absorption spectra of chlorophyll dyes, in this way increasing the photosynthetic activity of the plant. Here, we report on the application of this principle to a high plant, Spinacia oleracea. We employ a calcium strontium sulfide phosphor doped with divalent europium (Ca0.4Sr0.6S:Eu(2+), CSSE) on a backlight conversion foil in photosynthesis experiments. We show that this phosphor can be used to effectively convert green to red light, centering at a wavelength of ~650 nm which overlaps the absorption peaks of chlorophyll a/b pigments. A measurement system was developed to monitor the photosynthetic activity, expressed as the CO2 assimilation rate of spinach leaves under various controlled light conditions. Results show that under identical external light supply which is rich in green photons, the CO2 assimilation rate can be enhanced by more than 25% when the actinic light is modified by the CSSE conversion foil as compared to a purely reflecting reference foil. These results show that the phosphor could be potentially applied to modify the solar spectrum by converting the green photons into photosynthetically active red photons for improved photosynthetic activity.

  3. Non Radiation Hardened Microprocessors in Spaced Based Remote Sensing Systems

    NASA Technical Reports Server (NTRS)

    Decoursey, Robert J.; Estes, Robert F.; Melton, Ryan

    2006-01-01

    (SEU) and Single Event Latch-up (SEL) rates. Although less significant, spacecraft flying in the area around the poles experience similar upsets. Finally, powerful solar proton events in the range of 10MeV/10pfu to 100MeV/1pfu as are forecasted and tracked by NOAA's Space Environment Center in Colorado can result in Single Event Upset (SEU), Single Event Latch-up (SEL) and permanent failures such as Single Event Gate Rupture (SEGR) in some technologies. (Galactic Cosmic Rays (GCRs) are another source, especially for gate rupture) CALIPSO mitigates common radiation concerns in its data handling through the use of redundant processors, radiation-hardened Application Specific Integrated Circuits (ASIC), hardware-based Error Detection and Correction (EDAC), processor and memory scrubbing, redundant boot code and mirrored files. After presenting a system overview this paper will expand on each of these strategies. Where applicable, related on-orbit data collected since the CALIPSO initial boot on May 4, 2006 will be noted.

  4. What Reliability Engineers Should Know about Space Radiation Effects

    NASA Technical Reports Server (NTRS)

    DiBari, Rebecca

    2013-01-01

    current of a nearby Thermal Electric Cooler (turning the TEC into a heater). The elevated temperature caused the PIN diode to anneal and the device to recover. It was by lot qualification testing that NEAR knew the diode would recover when annealed. This paper will look at these effects on a variety of devices in a variety of applications. Single Event Effects (SEE): (1) In contrast to TID and displacement damage, Single Event Effects (SEE) resemble random failures. SEE modes can range from changes in device logic (single-event upset, or SEU). temporary disturbances (single-event transient) to catastrophic effects such as the destructive SEE modes, single-event latchup (SEL). single-event gate rupture (SEGR) and single-event burnout (SEB) (2) The consequences of nondestructive SEE modes such as SEU and SET depend critically on their application--and may range from trivial nuisance errors to catastrophic loss of mission. It is critical not just to ensure that potentially susceptible devices are well characterized for their susceptibility, but also to work with design engineers to understand the implications of each error mode. -For destructive SEE, the predominant risk mitigation strategy is to avoid susceptible parts, or if that is not possible. to avoid conditions under which the part may be susceptible. Destructive SEE mechanisms are often not well understood, and testing is slow and expensive, making rate prediction very challenging. (3) Because the consequences of radiation failure and degradation modes depend so critically on the application as well as the component technology, it is essential that radiation, component. design and system engineers work togetherpreferably starting early in the program to ensure critical applications are addressed in time to optimize the probability of mission success.

  5. Off-Label and Unlicensed Drug Use in Neonatology: Reality in a Portuguese University Hospital.

    PubMed

    Silva, Joana; Flor-de-Lima, Filipa; Soares, Henrique; Guimarães, Hercília

    2015-01-01

    Introdução: Este estudo pretende caracterizar os medicamentos usados numa Unidade de Cuidados Intensivos Neonatais portuguesa, avaliar a frequência do uso de fármacos off-label ou não licenciados de acordo com a informação disponível no Resumo das Caraterísticas do Medicamento e comparar resultados entre recém-nascidos prematuros e de termo.Material e Métodos: Um estudo retrospetivo transversal foi conduzido na nossa Unidade de Cuidados Intensivos Neonatais no primeiro semestre de 2013. Os dados das prescrições realizadas foram comparados com a informação pediátrica contida nos Resumos das Caraterísticas do Medicamento.Resultados: Analisámos 1011 prescrições respeitantes a 84 substâncias ativas, feitas em 218 admissões. Em 42,9% dos casos, os fármacos foram usados de acordo com a informação do Resumo das Caraterísticas do Medicamento; 27,9% dos fármacos eram aprovados para o período neonatal mas usados de forma off-label; medicamentos off-label para a idade neonatal foram usados em 10,1%, enquanto aqueles com estado de aprovação indeterminado ou contraindicados foram usados em 6,0% e 8,7% dos casos, respetivamente. As prescrições não licenciadas representaram 4,4% do total. Os recém-nascidos pré-termo receberam uma taxa superiorde fármacos usados de acordo com o Resumo das Caraterísticas do Medicamento (p < 0,0001), enquanto os de termo receberam mais fármacos off-label para dose/frequência (p < 0,0001) e contraindicados para recém-nascidos (p < 0,012).Discussão: Os prematuros receberam um número mediano de fármacos superior, o que se relaciona com o seu internamento mais prolongado. A principal razão para prescrições off-label foi a utilização de doses/frequências de administração diferentes das referidas no Resumo das Caraterísticas do Medicamento, reforçando a necessidade de atualização destes documentos. A manipulação dosmedicamentos é uma das causas para o seu uso não licenciado, enfatizando a falta de

  6. Non-radiation hardened microprocessors in space-based remote sensing systems

    NASA Astrophysics Data System (ADS)

    DeCoursey, R.; Melton, Ryan; Estes, Robert R., Jr.

    2006-09-01

    normal Single Event Upset (SEU) and Single Event Latch-up (SEL) rates. Although less significant, spacecraft flying in the area around the poles experience similar upsets. Finally, powerful solar proton events in the range of 10MeV/10pfu to 100MeV/1pfu as are forecasted and tracked by NOAA's Space Environment Center in Colorado can result in SingleEvent Upset (SEU), Single Event Latch-up (SEL) and permanent failures such as Single Event Gate Rupture (SEGR) in some technologies. (Galactic Cosmic Rays (GCRs) are another source, especially for gate rupture) CALIPSO mitigates common radiation concerns in its data handling through the use of redundant processors, radiation-hardened Application Specific Integrated Circuits (ASIC), hardware-based Error Detection and Correction (EDAC), processor and memory scrubbing, redundant boot code and mirrored files. After presenting a system overview this paper will expand on each of these strategies. Where applicable, related on-orbit data collected since the CALIPSO initial boot on May 4, 2006 will be noted.

  7. Development of the TabacoQuest app for computerization of data collection on smoking in psychiatric nursing.

    PubMed

    Oliveira, Renata Marques de; Duarte, Alexandre Freitas; Alves, Domingos; Furegato, Antonia Regina Ferreira

    2016-08-29

    to develop a mobile app for research on the use of tobacco among psychiatric patients and the general population. applied research with the technological development of an app for data collection on an Android tablet. For its development, we considered three criteria: data security, benefits for participants and optimization of the time of researchers. We performed tests with twenty fictitious participants and a final test with six pilots. the app collects data, stores them in the database of the tablet and export then to an Excel spreadsheet. calculator, stopwatch, offline operation, branching logic, field validation and automatic tabulation. the app prevents human error, increases the quality of the data by validating them during the interview, allows the performing of automatic tabulation and makes the interviews less tiring. Its success may encourage the use of this and other computational resources by nurses as a research tool. desenvolver aplicativo mobile para pesquisa sobre o uso de tabaco entre pacientes psiquiátricos e a população geral. pesquisa aplicada com o desenvolvimento tecnológico de um aplicativo para coleta de dados em tablet Android. Para seu desenvolvimento, consideraram-se três critérios: segurança dos dados, benefícios para os participantes e otimização do tempo dos pesquisadores. Testes com 20 participantes fictícios e teste final com seis pilotos. o aplicativo coleta os dados, armazena-os no banco de dados do tablet e os exporta para planilha Excel. Recursos: calculadora; cronômetro; funcionamento off-line, lógica de ramificação, validação de campos e tabulação automática. o aplicativo previne erros humanos e aumenta a qualidade dos dados ao validá-los durante a entrevista, permite realizar tabulação automática e torna as entrevistas menos cansativas. Seu sucesso poderá incentivar o uso desse e outros recursos computacionais pelos enfermeiros, como ferramenta de pesquisa. desarrollar aplicativo móvil para hacer

  8. Variable Depth Bragg Peak Method for Single Event Effects Testing

    NASA Technical Reports Server (NTRS)

    Buchner, S.; Kanyogoro, N.; Foster, C.; O'Neill, P.

    2011-01-01

    Traditionally, accelerator SEE testing is accomplished by removing the tops of packages so that the IC chips are accessible to heavy ions. However, ICs in some advanced packages cannot be de-lidded so a different approach is used that involves grinding and/or chemically etching away part of the package and the chip from the back side. The parts are then tested from the back side with ions having sufficient range to reach the sensitive volume. More recently, the entire silicon substrate in an SOI/SRAM was removed, making it possible to use low-energy ions with shorter ranges. Where removal of part of the package is not possible, facilities at Michigan State, NASA Space Radiation Laboratory, GANIL (France) and GSI (Germany) offer high-energy heavy ions with long ranges so that the ions can reach the devices' sensitive volumes without much change in the LET. Unfortunately, a run will typically involve only one ion species having a single energy and LET due to the long time it takes to tune a new energy. The Variable Depth Bragg Peak (VDBP) method is similar to the above method in that it involves the use of high-energy heavy ions that are able to pass through the packaging material and reach the device, obviating the need to remove the package. However, the method provides a broad range of LETs from a single ion by inserting degraders in the beam that modify the ion energy and, therefore, the LET. The crux of the method involves establishing a fiduciary point for degrader thickness, i.e., where the Bragg peak is located precisely at the sensitive volume in the device, for which the measured SEU cross-section and the ion LET are both also maxima and can be calculated using a Monte-Carlo program, TRIM. Once the fiduciary point has been established, calibrated high density polyethylene (HDPE) degraders are inserted into or removed from the beam to vary the ion LET at the device in a known manner. After each change of degrader thickness, the SEU cross-section is measured

  9. The North Polar Layered Deposits on Mars: The Internal Layering of Gemina Lingula and Implications for Ice Flow

    NASA Astrophysics Data System (ADS)

    Karlsson, Nanna B.; Holt, John W.; Hindmarsh, Richard C. A.; Choudhary, Prateek

    2010-05-01

    The North Polar Layered Deposits (NPLD) is one of the largest reservoirs of surface water on Mars and, via an active exchange of water vapour with the atmosphere, it plays an important role in the Martian climate. The impact of ice flow on the overall shape of the NPLD is still widely debated. A study by Winebrenner et al. (2008) found evidence for relict flow lines in the southernmost part of the NPLD called Gemina Lingula (GL). Other studies have concluded that the upper part of the NPLD shows no evidence of flow (Fishbaugh and Hvidberg, 2006) and that surface mass balance alone can produce the topography (Greve et al., 2004 and Greve and Mahajan, 2005) . This paper presents results from an analysis of radar data from the SHARAD (SHallow RADar) instrument on board NASA's Mars Reconnaissance Orbiter. The SHARAD instrument operates with a 20MHz centre frequency and a 10MHz bandwidth and one of its primary mission goals is to map the state and distribution of water on Mars. For more details on the SHARAD instrument please refer to Seu et al. (2007). In the SHARAD data we identified and mapped six internal horizons from over 80 radar lines retrieved over GL. All horizons were easily identifiable in the majority of the data and were on average present in over 80% of the radar data considered. The observed layers were then compared to modelled layers from a 3D ice flow model. The model uses a smoothed surface topography, where troughs and scarps have been filled in, and assumes that the shape and the mass balance of the NPLD are constant in time. The shape of the internal layers are then calculated as they would appear in a flowing ice cap given those parameters. More information on the model can be found in Hindmarsh et al. (2009). The overall fit between modelled and observed layers is reasonably good, but the goodness of the fit varies both between the different horizons and the different regions of GL. Horizons in the upper part of the ice fit less well than

  10. Parcial Nephrectomies - results of 12 years from an Oncology Institution.

    PubMed

    Freitas, Rui; Cruz, Ricardo; Antunes, Luís; Araújo, Paulo; Silva, Pedro; Saraiva, Luis; Magalhães, Sanches; Moreira Silva, Vitor; Morais, António; Lobo, Francisco; Oliveira, Jorge

    2016-02-01

    Introdução: O diagnóstico de carcinoma de células renais tem vindo a aumentar nos últimos anos, sobretudo pelo seu diagnóstico incidental, e de forma paralela tem aumentado as indicações para cirurgia preservadora de nefrónios.Objectivos: Rever uma série de nefrectomias parciais de uma instituição oncológica em termos técnicos, sobrevida, variação da função renal. Material e Métodos: Análise retrospectiva de todos os doentes com neoplasia renal, submetidos a nefrectomia parcial na nossa instituição entre janeiro de 2000 e dezembro de 2012. Resultados: Foram realizadas 156 nefrectomias parciais, 85 em homens e 71 em mulheres, com média de idades de 62 '± 15 anos. A abordagem foi em 23 casos transperitoneal laparoscópica sendo nos restantes 133 por lombotomia. O tempo médio de isquemia foi < 25 minutos em todos os doentes. A taxa de complicações foi de 10,9%, a maioria grau 2 e 3 da escala de Clavien-Dindo. Os tumores tinham dimensões médias de 2,9 '± 1,4 cm e a margem cirúrgica estava focalmente atingida por tumor em 9,6% dos casos. Em termos histológicos, verificou-se em 26,2% dos casos a existência de carcinoma de células renais de células claras, sendo os oncocitomas a neoplasia benigna mais frequente com 14,7% do total. No seguimento dos doentes verificaram-se 4 casos de recidiva e um óbito pela doença. A variação média na taxa de filtração glomerular estimada foi de -5,3 mL/min por 1,73 m2 (p < 0,001). Não se verificou associação entre tempo de isquemia, índice de massa corporal, idade, score ASA, existência de complicações com este decréscimo da taxa de filtração glomerular. Discussão: Os casos de margens cirúrgicas positivas são ligeiramente superiores ao descrito na literatura, todavia não foram encontrados factores preditivos para tal e em última análise não foi encontrada recidiva tumoral ou qualquer influência na sobrevida destes doentes. Apesar de ter se ter verificado uma diminui

  11. [Fractional exhaled nitric oxide in monitoring and therapeutic management of asthma].

    PubMed

    Melo, Bruno; Costa, Patrício; Afonso, Ariana; Machado, Vânia; Moreira, Carla; Gonçalves, Augusta; Gonçalves, Jean-Pierre

    2014-01-01

    Introdução: A asma é uma doença respiratória crónica caracterizada pela hiper-reactividade e inflamação brônquica. A inflamação brônquica destes doentes pode ser monitorizada através da medição da fração exalada de óxido nítrico. Este estudo tem por objetivo determinar a associação do valor da fração exalada de óxido nítrico com o débito expiratório máximo instantâneo e com o controlo da asma determinado pela Classificação da Iniciativa Global para a Asma.Material e Métodos: Estudo observacional, analítico e transversal de crianças com asma, 6-12 anos, seguidas na Consulta Externa de Patologia Respiratória do Hospital de Braga. Informação sociodemográfica e clínica colhida através de um questionário. Determinado o valor da fração exalada de óxido nítrico, através do analisador portátil Niox Mino®, e do débito expiratório máximo instantâneo,através do debitómetro.Resultados: A amostra é constituída por 101 crianças asmáticas, 63 (62,4%) do sexo masculino e 38 (37,6%) do sexo feminino. A idade média dos participantes na amostra é de 9,18 (1,99) anos. A regressão logística, realizada com o valor de cutoff obtido pela curva de ROC, revelou que a fração exalada de óxido nítrico tem um efeito estatisticamente significativo (bNíveis do FENO = 0,85; χ2Wald (1) = 8,71; OR = 2,33; p = 0,003) sobre a probabilidade de mudar de nível de controlo da asma. Por cada nível de fração exalada de óxido nítrico incrementado o odds de passar a não controlada é 2,33 vezes superior.Discussão e Conclusão: A probabilidade de uma criança asmática mudar o seu nível de controlo da asma, de ‘controlada’ para ‘parcialmente controlada/não controlada’, tendo em consideração uma alteração no seu nível da fração exalada de óxido nítrico, aumenta 133%.

  12. SINGLE EVENT EFFECTS TEST FACILITY AT OAK RIDGE NATIONAL LABORATORY

    SciTech Connect

    Riemer, Bernie; Gallmeier, Franz X; Dominik, Laura J

    2015-01-01

    Increasing use of microelectronics of ever diminishing feature size in avionics systems has led to a growing Single Event Effects (SEE) susceptibility arising from the highly ionizing interactions of cosmic rays and solar particles. Single event effects caused by atmospheric radiation have been recognized in recent years as a design issue for avionics equipment and systems. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered, including testing of the components and systems in a neutron beam. Testing of ICs and systems for use in radiation environments requires the utilization of highly advanced laboratory facilities that can run evaluations on microcircuits for the effects of radiation. This paper provides a background of the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions. A study investigating requirements for future single event effect irradiation test facilities and developing options at the Spallation Neutron Source (SNS) is summarized. The relatively new SNS with its 1.0 GeV proton beam, typical operation of 5000 h per year, expertise in spallation neutron sources, user program infrastructure, and decades of useful life ahead is well suited for hosting a world-class SEE test facility in North America. Emphasis was put on testing of large avionics systems while still providing tunable high flux irradiation conditions for component tests. Makers of ground-based systems would also be served well by these facilities. Three options are described; the most capable, flexible, and highest-test-capacity option is a new stand-alone target station using about one kW of proton beam power on a gas-cooled tungsten target, with dual test enclosures. Less expensive options are also described.

  13. The effects of heavy ion radiation on digital micromirror device performance

    NASA Astrophysics Data System (ADS)

    Travinsky, Anton; Vorobiev, Dmitry; Ninkov, Zoran; Raisanen, Alan D.; Pellish, Jonathan A.; Robberto, Massimo; Heap, Sara

    2016-07-01

    There is a pressing need in the astronomical community for space-suitable multi-object spectrometers (MOSs). Several digital micromirror device (DMD)-based prototype MOSs have been developed for ground-based observatories; however, their main use will come with deployment on a space based mission. Therefore, performance of DMDs under exoatmospheric radiation needs to be evaluated. In our previous work we demonstrated that DMDs are tolerant to heavy ion irradiation in general and calculated upset rate of 4.3 micromirrors in 24 hours in orbit for 1-megapixel device. The goal of this additional experiment was to acquire more data and therefore increase the accuracy of the predicted in-orbit micromirror upset rate. Similar to the previous experiment, for this testing 0.7 XGA DMDs were re-windowed with 2 μm thick pellicle and tested under accelerated heavy-ion radiation (with control electronics shielded from radiation) with a focus on detection of single-event upsets (SEUs). We concentrated on ions with low levels of linear energy transfer (LET) 1.8 - 13 MeV•cm2•mg-1 to cover the most critical range of the Weibull curve for those devices. As during the previous experiment, we observed and documented non-destructive heavy ion-induced micromirror state changes. All SEUs were always cleared with a soft reset (that is, sending a new pattern to the device). The DMDs we tested did not experience single-event induced permanent damage or functional changes that required a hard reset (power cycle), even at high ion fluences. Based on the data obtained in the experiments we predict micromirror in-orbit upset rate of 5.6 micromirrors in 24 hours in-orbit for the tested devices. This suggests that the heavy-ion induced SEU rate burden for a DMD-based instrument will be manageable when exposed to solar particle fluxes and cosmic rays in orbit.

  14. Incorporando a variabilidade no processo de identificação do modelo de máximo global no Grade of Membership (GoM): considerações metodológicas

    PubMed Central

    Guedes, Gilvan Ramalho; Siviero, Pamila Cristina Lima; Caetano, André Junqueira; Machado, Carla Jorge; Brondízio, Eduardo

    2012-01-01

    A disponibilidade de bases de dados cada vez mais complexas e multidimensionais é um dos principais motivadores para o aumento do número de estudos que utilizam análises multivariadas baseadas em lógica de conjuntos nebulosos. Apesar da disseminação do método Grade of Membership nos trabalhos empíricos brasileiros da área de ciências sociais e saúde, questões relativas à identificabilidade e estabilidade dos parâmetros finais estimados pelo programa GoM 3.4 não foram suficientemente aprofundadas. Dada a relevância de se obterem parâmetros únicos e estáveis, Guedes et al. (2010) propuseram um procedimento empírico para localizar um modelo de máximo global (MG) com parâmetros estáveis. Entretanto, seu localizador de MG não incorpora qualquer medida de variabilidade. Neste artigo, tal limitação é contornada por meio da utilização de uma estatística de ponderação – Máximo Global Ponderado (MGP) – semelhante ao coeficiente de variação. Esse indicador busca não penalizar de forma desproporcional situações nas quais os desvios médios, apesar de diferentes de zero, são muito pequenos. Apresentam-se evidências de que o localizador MGP reduz a distância do modelo identificado à real estrutura latente dos dados em análise, quando comparados ao modelo identificado pelo localizador não ponderado, MG. PMID:23293402

  15. Education and Public Outreach Programs for Structure and Evolution of the Universe Themed Missions: CHIPS and SPIDR

    NASA Astrophysics Data System (ADS)

    Mendez, B. J.; Craig, N.

    2003-05-01

    The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) is the first NASA University-Class Explorer (UNEX) mission, and was launched on January 12th, 2003. It will study the extremely diffuse, hot gas inside the region surrounding the Sun out to a radius of about 300 light years known as the Local Bubble. The focus of the CHIPS education and outreach will be disseminating products produced during Phases C, and D to classrooms, and through professional development programs, science teacher conferences and other NASA OSS and SEU Education Forum branches. We have also developed an eight-page Educational Brief, titled "Cosmic Bubbles in the Interstellar Medium," for educators and students containing background information on the Interstellar Medium (ISM). Additional classroom testing and presentation of CHIPS activities will occur during Summer 2003 in Berkeley's Academic Talent Development (ATDP) program. One of NASA's newest SMEX missions is SPIDR (Spectroscopy and Photometry of the Intergalactic Medium's Diffuse Radiation), which when launched in 2005 will study the "cosmic web" of intergalactic gas spanning the Universe. The E/PO during Phase B of SPIDR will focus on partnerships with UC Berkeley's Lawrence Hall of Science GEMS program (Great Explorations in Math and Science). The first joint venture of GEMS and SPIDR will be the launch of a new GEMS site at the Lodestar Astronomy Center located in the New Mexico Museum of Natural History and Science in Albuquerque, NM in June, 2003. The SPIDR E/PO team is also partnering with LHS in the development of a new GEMS Space Science Strand that will include activities focused on the size and scale of the Universe.

  16. BRAZILIAN CONSENSUS FOR MULTIMODAL TREATMENT OF COLORECTAL LIVER METASTASES. MODULE 3: CONTROVERSIES AND UNRESECTABLE METASTASES.

    PubMed

    Torres, Orlando Jorge Martins; Marques, Márcio Carmona; Santos, Fabio Nasser; Farias, Igor Correia de; Coutinho, Anelisa Kruschewsky; Oliveira, Cássio Virgílio Cavalcante de; Kalil, Antonio Nocchi; Mello, Celso Abdon Lopes de; Kruger, Jaime Arthur Pirola; Fernandes, Gustavo Dos Santos; Quireze, Claudemiro; Murad, André M; Silva, Milton José de Barros E; Zurstrassen, Charles Edouard; Freitas, Helano Carioca; Cruz, Marcelo Rocha; Weschenfelder, Rui; Linhares, Marcelo Moura; Castro, Leonaldson Dos Santos; Vollmer, Charles; Dixon, Elijah; Ribeiro, Héber Salvador de Castro; Coimbra, Felipe José Fernandez

    2016-01-01

    In the last module of this consensus, controversial topics were discussed. Management of the disease after progression during first line chemotherapy was the first discussion. Next, the benefits of liver resection in the presence of extra-hepatic disease were debated, as soon as, the best sequence of treatment. Conversion chemotherapy in the presence of unresectable liver disease was also discussed in this module. Lastly, the approach to the unresectable disease was also discussed, focusing in the best chemotherapy regimens and hole of chemo-embolization. RESUMO Neste último módulo do consenso, abordou-se alguns temas controversos. O primeiro tópico discutido foi o manejo da doença após progressão na primeira linha de quimioterapia, com foco em se ainda haveria indicação cirúrgica neste cenário. A seguir, o painel debruçou-se sobre as situações de ressecção da doença hepática na presença de doença extra-hepática, assim como, qual a melhor sequência de tratamento. O tratamento de conversão para doença inicialmente irressecável também foi abordado neste módulo, incluindo as importantes definições de quando se pode esperar que a doença se torne ressecável e quais esquemas terapêuticos seriam mais efetivos à luz dos conhecimentos atuais sobre a biologia tumoral e taxas de resposta objetiva. Por último, o tratamento da doença não passível de ressecção foi discutida, focando-se nos melhores esquemas a serem empregados e seu sequenciamento, bem como o papel da quimioembolização no manejo destes pacientes.

  17. A framework for energy use indicators and their reporting in life cycle assessment.

    PubMed

    Arvidsson, Rickard; Svanström, Magdalena

    2016-07-01

    Energy use is a common impact category in life cycle assessment (LCA). Many different energy use indicators are used in LCA studies, accounting for energy use in different ways. Often, however, the choice behind which energy use indicator is applied is poorly described and motivated. To contribute to a more purposeful selection of energy use indicators and to ensure consistent and transparent reporting of energy use in LCA, a general framework for energy use indicator construction and reporting in LCA studies will be presented in this article. The framework differentiates between 1) renewable and nonrenewable energies, 2) primary and secondary energies, and 3) energy intended for energy purposes versus energy intended for material purposes. This framework is described both graphically and mathematically. Furthermore, the framework is illustrated through application to a number of energy use indicators that are frequently used in LCA studies: cumulative energy demand (CED), nonrenewable cumulative energy demand (NRCED), fossil energy use (FEU), primary fossil energy use (PFEU), and secondary energy use (SEU). To illustrate how the application of different energy use indicators may lead to different results, cradle-to-gate energy use of the bionanomaterial cellulose nanofibrils (CNF) is assessed using 5 different indicators and showing a factor of 3 differences between the highest and lowest results. The relevance of different energy use indicators to different actors and contexts will be discussed, and further developments of the framework are then suggested. Integr Environ Assess Manag 2016;12:429-436. © 2015 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC.

  18. Angioqueratomas de fordyce múltiplos de vulva associados à cirrose hepática.

    PubMed

    Souza Teixeira, Marcelo; Dos Santos Lima, Caren; De Abreu Neves Salles1, Simone; Luz, Flávio Barbosa; Roberta Duarte Bezerra Pinto, Roberta; Pantaleão, Luciana

    2016-05-15

    Fordyce angiokeratoma is a benign skin neoplasm, characterized by erythematous-violet keratotic papules with mamillated surface, which follows a chronic and minimally symptomatic course. However, symptoms can be related such as itching, burning, bleeding, dyspareunia; aesthetic and social concerns may prompt request for treatment. The condition mainly affects men and usually occurs in the scrotum, but rarely may occur in women. A 30-year-old woman with liver cirrhosis and portal hypertension is described. Over a period of two years she developed multiple angiokeratomas of the vulva, complicated by frequent bleeding. Histopathologic analysis of the lesion confirmed the diagnosis of angiokeratoma and all lesions were surgically removed. The results of the treatment were very satisfactory, with no relapses or complications.Angioqueratoma de Fordyce é uma dermatose incomum que compõe o grupo das neoplasias cutâneas benignas, caracterizando-se pelo aparecimento de lesões papuloceratósicas, eritemato-violáceas de superfície mamilonada, que apresentam curso crônico e oligossintomático. No entanto, outros sintomas podem estar associados, como prurido, ardência, sangramento e dispareunia, além de problemas estéticos e de ordem social. Afeta principalmente homens, acometendo a região escrotal, sendo raro seu surgimento em mulheres. Relata-se caso de uma paciente com 30 anos de idade, portadora de cirrose hepática e hipertensão portal evoluindo há 2 anos com múltiplos angioqueratomas na vulva de sangramento frequente. A análise histopatológica confirmou o diagnóstico de angioqueratoma e a paciente foi submetida à exérese cirúrgica das lesões. Os resultados terapêuticos foram satisfatórios, sem recidivas ou complicações.

  19. Compact CMOS Camera Demonstrator (C3D) for Ukube-1

    NASA Astrophysics Data System (ADS)

    Harriss, R. D.; Holland, A. D.; Barber, S. J.; Karout, S.; Burgon, R.; Dryer, B. J.; Murray, N. J.; Hall, D. J.; Smith, P. H.; Grieg, T.; Tutt, J. H.; Endicott, J.; Jerram, P.; Morris, D.; Robbins, M.; Prevost, V.; Holland, K.

    2011-09-01

    The Open University, in collaboration with e2v technologies and XCAM Ltd, have been selected to fly an EO (Earth Observation) technology demonstrator and in-orbit radiation damage characterisation instrument on board the UK Space Agency's UKube-1 pilot Cubesat programme. Cubesat payloads offer a unique opportunity to rapidly build and fly space hardware for minimal cost, providing easy access to the space environment. Based around the e2v 1.3 MPixel 0.18 micron process eye-on-Si CMOS devices, the instrument consists of a radiation characterisation imager as well as a narrow field imager (NFI) and a wide field imager (WFI). The narrow and wide field imagers are expected to achieve resolutions of 25 m and 350 m respectively from a 650 km orbit, providing sufficient swathe width to view the southern UK with the WFI and London with the NFI. The radiation characterisation experiment has been designed to verify and reinforce ground based testing that has been conducted on the e2v eye-on-Si family of devices and includes TEC temperature control circuitry as well as RADFET in-orbit dosimetry. Of particular interest are SEU and SEL effects. The novel instrument design allows for a wide range of capabilities within highly constrained mass, power and space budgets providing a model for future use on similarly constrained missions, such as planetary rovers. Scheduled for launch in December 2011, this 1 year low cost programme should not only provide valuable data and outreach opportunities but also help to prove flight heritage for future missions.

  20. Instruments used in the assessment of expectation toward a spine surgery: an integrative review.

    PubMed

    Nepomuceno, Eliane; Silveira, Renata Cristina de Campos Pereira; Dessotte, Carina Aparecida Marosti; Furuya, Rejane Kiyomi; Arantes, Eliana De Cássia; Cunha, Débora Cristine Prévide Teixeira da; Dantas, Rosana Aparecida Spadoti

    2016-01-01

    To identify and describe the instruments used to assess patients' expectations toward spine surgery. An integrative review was carried out in the databases PubMed, CINAHL, LILACS and PsycINFO. A total of 4,402 publications were identified, of which 25 met the selection criteria. Of the studies selected, only three used tools that had confirmed validity and reliability to be applied; in five studies, clinical scores were used, and were modified for the assessment of patients' expectations, and in 17 studies the researchers developed scales without an adequate description of the method used for their development and validation. The assessment of patients' expectations has been methodologically conducted in different ways. Until the completion of this integrative review, only two valid and reliable instruments had been used in three of the selected studies. Identificar e descrever os instrumentos usados para avaliar a expectativa dos pacientes diante do tratamento cirúrgico da coluna vertebral. Revisão Integrativa realizada nas bases de dados PubMed, CINAHL, LILACS e PsycINFO. Identificamos 4.402 publicações, das quais 25 atenderam aos critérios de seleção. Dos estudos selecionados, apenas em três os autores utilizaram instrumentos que possuíam validade e confiabilidade confirmadas para serem aplicados; em cinco estudos foram utilizados escores clínicos, modificados para a avaliação das expectativas dos pacientes, e em dezessete os pesquisadores elaboraram escalas sem adequada descrição do método usado para o seu desenvolvimento e validação. A avaliação das expectativas dos pacientes tem sido metodologicamente conduzida de diferentes maneiras. Até a finalização desta revisão integrativa, apenas dois instrumentos, válidos e confiáveis, haviam sido utilizados em três dos estudos selecionados.

  1. The role of surgery in the management of women with gestational trophoblastic disease.

    PubMed

    Lima, Lana DE Lourdes Aguiar; Padron, Lílian; Câmara, Raphael; Sun, Sue Yazaki; Rezende, Jorge; Braga, Antônio

    2017-01-01

    The Gestational Trophoblastic Disease includes an interrelated group of diseases originating from placental tissue, with distinct behaviors concerning local invasion and metastasis. The high sensitivity of the serial dosages of human chorionic gonadotrophin, combined with advances in chemotherapy treatment, have made gestational trophoblastic neoplasia curable, most often through chemotherapy. However, surgery remains of major importance in the management of patients with gestational trophoblastic disease, improving their prognosis. Surgery is necessary in the control of the disease's complications, such as hemorrhage, and in cases of resistant/relapsed neoplasia. This review discusses the indications and the role of surgical interventions in the management of women with molar pregnancy and gestational trophoblastic neoplasia. RESUMO Doença trofoblástica gestacional inclui um grupo interrelacionado de doenças originadas do tecido placentário, com tendências distintas de invasão local e metástase. A alta sensibilidade das dosagens seriadas de gonadotrofina coriônica humana aliada aos avanços do tratamento quimioterápico tornou a neoplasia trofoblástica gestacional, curável, na maioria das vezes, através da quimioterapia. No entanto, a cirurgia permanece ainda, da maior importância na condução de pacientes com doença trofoblástica gestacional, melhorando seu prognóstico. A cirurgia é necessária no controle de complicações da doença, tais como hemorragia, e em casos de neoplasia resistente/recidivada. Esta revisão discute as indicações e o papel das intervenções cirúrgicas durante o manejo de mulheres com gravidez molar e neoplasia trofoblástica gestacional.

  2. Modeling indirect detectors for performance optimization of a digital mammographic detector for dual energy applications

    NASA Astrophysics Data System (ADS)

    Martini, N.; Koukou, V.; Kalyvas, N.; Sotiropoulou, P.; Michail, C.; Valais, I.; Bakas, A.; Kandarakis, I.; Nikiforidis, G.; Fountos, G.

    2015-01-01

    Dual Energy imaging is a promising method for visualizing masses and microcalcifications in digital mammography. The advent of two X-ray energies (low and high) requires a suitable detector. The scope of this work is to determine optimum detector parameters for dual energy applications. The detector was modeled through the linear cascaded (LCS) theory. It was assumed that a phosphor material was coupled to a CMOS photodetector (indirect detection). The pixel size was 22.5 μm. The phosphor thickness was allowed to vary between 20mg/cm2 and 160mg/cm2 The phosphor materials examined where Gd2O2S:Tb and Gd2O2S:Eu. Two Tungsten (W) anode X-ray spectra at 35 kV (filtered with 100 μm Palladium (Pd)) and 70 kV (filtered with 800 pm Ytterbium (Yb)), corresponding to low and high energy respectively, were considered to be incident on the detector. For each combination the contrast- to-noise ratio (CNR) and the detector optical gain (DOG), showing the sensitivity of the detector, were calculated. The 40 mg/cm2 and 70 mg/cm2 Gd2O2S:Tb exhibited the higher DOG values for the low and high energy correspondingly. Higher CNR between microcalcification and mammary gland exhibited the 70mg/cm2 and the 100mg/cm2 Gd2O2S:Tb for the low and the high energy correspondingly.

  3. A Versatile Link for High-Speed, Radiation Resistant Optical Transmission in LHC Upgrades

    NASA Astrophysics Data System (ADS)

    Xiang, A.; Gong, D.; Hou, S.; Huffman, T.; Kwan, S.; Liu, K.; Liu, T.; Prosser, A.; Soos, C.; Su, D.; Teng, P.; Troska, J.; Vasey, F.; Weidberg, T.; Ye, J.

    The Versatile Link project is developing a general purpose physical layer optical link with high bandwidth, radiation resistance and magnetic-field tolerance that meets the requirements of LHC upgrade experiments. This paper presents recent work on system specifications, front-end transceiver prototypes, passive components studies and commercial back-end transceiver evaluations. System optical power budgets are specified for single mode (1310nm) and multi-mode (850nm) links, with a target data rate of 4.8 Gbps and a transmission length of 150 meters. Noise and interference penalties are simulated using the 10GbE link model and verified by bit error ratio measurement on reference links. The power margin is particularly constrained by radiation degradation of the front-end receivers. We report the power budgets for all link variants where at least 1.8 dB safety margins are maintained. The Versatile Transceiver (VTRx) - the front-end module to be installed on-detector - is based on a commercial small form pluggable (SFP+) package, modified to optimize size and mass, assembled to host a qualified laser, PIN photodiode, custom-designed radiation tolerant laser driver and receiving amplifier. A set of VTRxs with validated components have been prototyped and compliance tested. We also present the radiation test results on front-end components and passive components. The total fluence tests for lasers and PINs have been carried out with pions and neutrons up to 4 x 1015/cm2. SEU tests have been performed on PIN photodiodes and the full receiver optical subassembly. Radiation induced absorption in a number of single mode and multi-mode fibers, at -25¡C and up to 500 kGy, have been measured and high performance candidates identified. Commercial off-of-the-shelf parts have been examined for use as back-end transceivers. Compliance tests on SFP+, 4+4 parallel optical engines and SNAP 12 transmitter/receivers have been completed.

  4. MOPITT Mechanisms 16 Years In-Orbit Operation on TERRA

    NASA Technical Reports Server (NTRS)

    Gibson, Andrew S.; Nichitiu, Florian; Caldwell, Dwight

    2016-01-01

    and SEU effects on accelerometers are also discussed.

  5. Educational interventions to improve inhaler techniques and their impact on asthma and COPD control: a pilot effectiveness-implementation trial.

    PubMed

    Maricoto, Tiago; Madanelo, Sofia; Rodrigues, Luís; Teixeira, Gilberto; Valente, Carla; Andrade, Lília; Saraiva, Alcina

    2016-01-01

    To assess the impact that educational interventions to improve inhaler techniques have on the clinical and functional control of asthma and COPD, we evaluated 44 participants before and after such an intervention. There was a significant decrease in the number of errors, and 20 patients (46%) significantly improved their technique regarding prior exhalation and breath hold. In the asthma group, there were significant improvements in the mean FEV1, FVC, and PEF (of 6.4%, 8.6%, and 8.3% respectively). Those improvements were accompanied by improvements in Control of Allergic Rhinitis and Asthma Test scores but not in Asthma Control Test scores. In the COPD group, there were no significant variations. In asthma patients, educational interventions appear to improve inhaler technique, clinical control, and functional control. RESUMO Para avaliar o impacto do ensino da técnica inalatória no controle clínico e funcional de pacientes com asma ou DPOC, incluíram-se 44 participantes antes e após essa intervenção. Houve uma diminuição significativa no número de erros cometidos, sendo que 20 pacientes (46%) melhoraram significativamente sua técnica na expiração prévia e apneia final. No grupo asma, houve significativa melhora nas médias de FEV1 (6,4%), CVF (8,6%) e PFE (8,3%), e essa melhora correlacionou-se com os resultados no Control of Allergic Rhinitis and Asthma Test, mas não com os do Asthma Control Test. No grupo DPOC, não houve variações significativas. O ensino da técnica inalatória parece melhorar seu desempenho e os controles clínico e funcional em pacientes com asma.

  6. OV-Wav: um novo pacote para análise multiescalar em astronomia

    NASA Astrophysics Data System (ADS)

    Pereira, D. N. E.; Rabaça, C. R.

    2003-08-01

    Wavelets e outras formas de análise multiescalar têm sido amplamente empregadas em diversas áreas do conhecimento, sendo reconhecidamente superiores a técnicas mais tradicionais, como as análises de Fourier e de Gabor, em certas aplicações. Embora a teoria dos wavelets tenha começado a ser elaborada há quase trinta anos, seu impacto no estudo de imagens astronômicas tem sido pequeno até bem recentemente. Apresentamos um conjunto de programas desenvolvidos ao longo dos últimos três anos no Observatório do Valongo/UFRJ que possibilitam aplicar essa poderosa ferramenta a problemas comuns em astronomia, como a remoção de ruído, a detecção hierárquica de fontes e a modelagem de objetos com perfis de brilho arbitrários em condições não ideais. Este pacote, desenvolvido para execução em plataforma IDL, teve sua primeira versão concluída recentemente e está sendo disponibilizado à comunidade científica de forma aberta. Mostramos também resultados de testes controlados ao quais submetemos os programas, com a sua aplicação a imagens artificiais, com resultados satisfatórios. Algumas aplicações astrofísicas foram estudadas com o uso do pacote, em caráter experimental, incluindo a análise da componente de luz difusa em grupos compactos de galáxias de Hickson e o estudo de subestruturas de nebulosas planetárias no espaço multiescalar.

  7. Perda de massa em ventos empoeirados de estrelas supergigantes

    NASA Astrophysics Data System (ADS)

    Vidotto, A. A.; Jatenco-Pereira, V.

    2003-08-01

    Em praticamente todas as regiões do diagrama HR, as estrelas apresentam evidências observacionais de perda de massa. Na literatura, pode-se encontrar trabalhos que tratam tanto do diagnóstico da perda de massa como da construção de modelos que visam explicá-la. O amortecimento de ondas Alfvén tem sido utilizado como mecanismo de aceleração de ventos homogêneos. Entretanto, sabe-se que os envelopes de estrelas frias contêm grãos sólidos e moléculas. Com o intuito de estudar a interação entre as ondas Alfvén e a poeira e a sua conseqüência na aceleração do vento estelar, Falceta-Gonçalves & Jatenco-Pereira (2002) desenvolveram um modelo de perda de massa para estrelas supergigantes. Neste trabalho, apresentamos um estudo do modelo acima proposto para avaliar a dependência da taxa de perda de massa com alguns parâmetros iniciais como, por exemplo, a densidade r0, o campo magnético B0, o comprimento de amortecimento da onda L0, seu fluxo f0, entre outros. Sendo assim, aumentando f0 de 10% a partir de valores de referência, vimos que aumenta consideravelmente, enquanto que um aumento de mesmo valor em r0, B0 e L0 acarreta uma diminuição em .

  8. Staphylococcus enterotoxin profile of China isolates and the superantigenicity of some novel enterotoxins.

    PubMed

    Shen, Menglu; Li, Yi; Zhang, Linlin; Dai, Songbao; Wang, Jiashun; Li, Yongqing; Zhang, Lei; Huang, Jinhai

    2017-02-24

    The genus of staphylococcus widely distributes in environments and contributes to a variety of animal and human diseases. The enterotoxins (SEs) secreted by this type of pathogen have been the leading cause of bacterial toxic shock syndrome and food poisoning, and thus present a substantial concern to public health. In this study, we analyzed the superantigen profile of 122 staphylococcus strains isolated from diverse sources. When screened for the presence and prevalence of 17 known se or se-like (sel) genes, except selj, all other genes were detected in these isolates. In particular, 95.9% of the isolates harbored at least one se/sel gene. Moreover, 47.5% of them bore at least 5. Remarkably, several non-pathogenic species of animal- and environment-origin were also found to carry multiple se/sels. The most frequent genes detected were tsst (62.3%), sei (54.1%), and seb (46.7%), followed by some sel genes (selo, selu, and selm), which also were present at relatively high frequency (20-30%). The generated data improved understanding of strain-specific differences in enterotoxin expression. The gene products of the latter (selo and selu) were subsequently analyzed for their antigenicity in a mouse model using purified E. coli-based recombinant proteins. The studies revealed a strong activity for SEO in induction of T-lymphocyte proliferation and production of various inflammatory cytokines either in vivo or in vitro. In contrast, SEU exhibited little superantigenic effects. The molecular basis for the difference in antigenicity was analyzed by 3D homology remodeling, which revealed a difference in binding and affinities for MHC-II molecules and TCR Vβ region.

  9. Are Current SEE Test Procedures Adequate for Modern Devices and Electronics Technologies?

    NASA Technical Reports Server (NTRS)

    LaBel, Kenneth A.; Cohn, Lewis M.; Ladbury, Ray

    2008-01-01

    Believe it or not, this has been a simplistic look at starting a checklist for SEE testing. Given a memory that has 68 operating modes, when a SEU occurs that changes the mode, just how do you determine what's going on? Laser and microbeam tests can help, but not easily for modern packaged devices. Expanding this approach to other more complex devices such as ADCs or processors as well as analog devices should be considered. The recommendation is to use the existing text standards as the starting point. Just make your own checklist for the device/technology/issues being considered. At HEART 2007, we presented some of the burgeoning challenges associated with single event effect(SEE) testing of modern commercial memories: a) Package, device complexity, test fixture, and data analysis issues were discussed; b) "Complete" SEE Characterization would take 15 years; c) Qualification test costs have a greater than 4 times increase over the last decade. In this talk, we continue to explore the roles of technology with an emphasis on the existing SEE Test Procedures and some of the concerns related to modern devices. The primary objective of the briefing is to provide some overarching guidance concerning the many considerations involved in the formulation of a SEE test plan provided in a " Checklist" format.we note that there is no such thing as a complete check list and that the best approach is to develop a flexible test plan that takes into account the device type and functions, the device technology, circuit and package design, and, of course, test facility and beam characteristics.

  10. Ionizing Radiation Environment on the International Space Station: Performance vs. Expectations for Avionics and Material

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L.; Boeder, Paul A.; Pankop, Courtney; Reddell, Brandon

    2005-01-01

    The role of structural shielding mass in the design, verification, and in-flight performance of International Space Station (ISS), in both the natural and induced orbital ionizing radiation (IR) environments, is reported. Detailed consideration of the effects of both the natural and induced ionizing radiation environment during ISS design, development, and flight operations has produced a safe, efficient manned space platform that is largely immune to deleterious effects of the LEO ionizing radiation environment. The assumption of a small shielding mass for purposes of design and verification has been shown to be a valid worst-case approximation approach to design for reliability, though predicted dependences of single event effect (SEE) effects on latitude, longitude, SEP events, and spacecraft structural shielding mass are not observed. The Figure of Merit (FOM) method over predicts the rate for median shielding masses of about 10g/cm(exp 2) by only a factor of 3, while the Scott Effective Flux Approach (SEFA) method overestimated by about one order of magnitude as expected. The Integral Rectangular Parallelepiped (IRPP), SEFA, and FOM methods for estimating on-orbit (Single Event Upsets) SEU rates all utilize some version of the CREME-96 treatment of energetic particle interaction with structural shielding, which has been shown to underestimate the production of secondary particles in heavily shielded manned spacecraft. The need for more work directed to development of a practical understanding of secondary particle production in massive structural shielding for SEE design and verification is indicated. In contrast, total dose estimates using CAD based shielding mass distributions functions and the Shieldose Code provided a reasonable accurate estimate of accumulated dose in Grays internal to the ISS pressurized elements, albeit as a result of using worst-on-worst case assumptions (500 km altitude x 2) that compensate for ignoring both GCR and secondary particle

  11. Comparação de modelos para o cálculo de perturbações orbitais devidas à maré terrestre

    NASA Astrophysics Data System (ADS)

    Vieira Pinto, J.; Vilhena de Moraes, R.

    2003-08-01

    Aplicações recentes de satélites artificiais com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais tem sido medidas por diversos processos. A atração exercida pela lua e pelo sol sobre a terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na terra, consequentemente no geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas a maré terrestre podem ser estudadas a partir das equações de Lagrange, considerando-se um conveniente potencial. Por outro lado, como tem sido feito pelo IERS, as mudanças induzidas pela maré terrestre no geopotencial podem ser convenientemente modeladas como variações nos coeficientes Cnm e Snm do geopotencial. As duas teorias ainda não foram comparados para um mesmo satélite. Neste trabalho são apresentadas e comparadas as variações de longo período e seculares nas perturbações orbitais devidas à maré terrestre, calculadas por um modelo simples, o de Kozai, e pelo modelo do IERS. Resultados preliminares mostram, para os satélites SCD2 e CBERS1, e para a Lua em movimento elíptico e precessionando, as perturbações seculares no argumento do perigeu e na longitude do nodo ascendente.

  12. The history of the parathyroid surgery.

    PubMed

    Toneto, Marcelo Garcia; Prill, Shandi; Debon, Leticia Manoel; Furlan, Fernando Zucuni; Steffen, Nedio

    2016-01-01

    The authors conducted a review of the major aspects of progression of knowledge about the surgical treatment of hyperparathyroidism. Through literature review, we analyzed articles on the history of the evolution of anatomical, physiological, pathological and surgical knowledge of the parathyroid glands. Because of their unique anatomical features, the parathyroid glands were the last of the endocrine glands to be discovered, which greatly hindered proper treatment until the first decades of the twentieth century. Technological developments in the last 30 years greatly facilitated the location of the glands and hyperparathyroidism surgery. However, an experienced and dedicated surgeon is still essential to the excellence of treatment. RESUMO Os autores fizeram uma revisão dos principais aspectos históricos da progressão do conhecimento sobre o tratamento cirúrgico do hiperparatireoidismo. Por meio de revisão bibliográfica, foram analisados artigos selecionados sobre a história da evolução do conhecimento anatômico, fisiológico, patológico e cirúrgico das glândulas paratireoides. Devido às suas características anatômicas peculiares, as paratireoides foram as últimas das glândulas endócrinas a serem descobertas, o que dificultou sobremaneira seu tratamento adequado até as primeiras décadas do Século XX. A evolução tecnológica ocorrida nos últimos 30 anos facilitou sobremaneira a localização das glândulas e a cirurgia do hiperparatireoidismo. Contudo, um cirurgião experiente e dedicado ao tratamento dessa enfermidade ainda é fundamental para a excelência do tratamento.

  13. MOPITT Mechanisms 16 Years In-Orbit Operation on TERRA

    NASA Technical Reports Server (NTRS)

    Gibson, Andrew S.; Nichitiu, Florian; Caldwell, Dwight

    2016-01-01

    and SEU effects on accelerometers are also discussed.

  14. The Illness Experience: Palliative Care Given the impossibility of Healing.

    PubMed

    Dantas, Margarida Maria Florêncio; Amazonas, Maria Cristina Lopes de Almeida

    2016-06-01

    This paper presents a reflection about being terminally ill and the various ways that the subject has at its disposal to deal with this event. The objective is to understand the experience of palliation for patients undergoing no therapeutic possibilities of cure. The methodology of this study has the instruments to semi-structured interview, the participant observation and the field diary, and the Descriptive Analysis of Foucault's inspiration how the narratives of the subjects were perceived. The Results of paper there was the possibility of looking at the experience of illness through the eyes of a subject position assumed by the very sick. As conclusion we have than when choosing palliative care, the terminally ill opts for a way to feel more comfortable and resists the impositions of the medical model of prolonging life. O presente trabalho traz uma reflexão a respeito do ser um doente terminal e das várias maneiras que o sujeito tem a seu dispor para lidar com esse acontecimento. Nosso objetivo foi compreender a experiência da paliação por sujeitos doentes sem possibilidades terapêuticas de cura. A metodologia deste estudo teve como instrumentos a Entrevista Narrativa, a Observação Participante e o Diário de Campo, sendo a Análise Descritiva de inspiração foucaultiana o modo como as narrativas dos sujeitos foram percebidas. O resultado do estudo mostrou a possibilidade de olhar a experiência do adoecer através da ótica de uma posição de sujeito assumida pelo próprio enfermo. E concluímos que ao escolher os cuidados paliativos, o doente terminal opta por um modo de se sentir mais confortável e resiste às imposições do modelo médico de prolongamento da vida.

  15. Study of the VMM1 read-out chip in a neutron irradiation environment

    NASA Astrophysics Data System (ADS)

    Alexopoulos, T.; Fanourakis, G.; Geralis, T.; Kokkoris, M.; Kourkoumeli-Charalampidi, A.; Papageorgiou, K.; Tsipolitis, G.

    2016-05-01

    Within 2015, the LHC operated close to the design energy of √s = 13-14 TeV delivering instantaneous luminosities up to Script L = 5 × 1033 cm-2s-1. The ATLAS Phase-I upgrade in 2018/19 will introduce the MicroMEGAS detectors in the area of the small wheel at the end caps. Accompanying new electronics are designed and built such as the VMM front end ASIC, which provides energy, timing and triggering information and allows fast data read-out. The first VMM version (VMM1) has been widely produced and tested in various test beams, whilst the second version (VMM2) is currently being tested. This paper focuses on the VMM1 single event upset studies and more specifically on the response of the configuration registers under harsh radiation environments. Similar conditions are expected at Run III with Script L = 2 × 1034 cm-2s-1 and a mean of 55 interactions per bunch crossing. Two VMM1s were exposed in a neutron irradiation environment using the TANDEM Van Der Graaff accelerator at NSCR Demokritos, Athens, Greece. The results showed a rate of SEU occurrences at a measured cross section of (4.1±0.8)×10-14 cm2/bit for each VMM. Consequently, when extrapolating this value to the luminosity expected in Run III, the occurrence is roughly 6 SEUs/min in all the read-out system comprising 40,000 VMMs installed during the Phase-I upgrade.

  16. Sequence-based prediction of DNA-binding residues in proteins with conservation and correlation information.

    PubMed

    Ma, Xin; Guo, Jing; Liu, Hong-De; Xie, Jian-Ming; Sun, Xiao

    2012-01-01

    The recognition of DNA-binding residues in proteins is critical to our understanding of the mechanisms of DNA-protein interactions, gene expression, and for guiding drug design. Therefore, a prediction method DNABR (DNA Binding Residues) is proposed for predicting DNA-binding residues in protein sequences using the random forest (RF) classifier with sequence-based features. Two types of novel sequence features are proposed in this study, which reflect the information about the conservation of physicochemical properties of the amino acids, and the correlation of amino acids between different sequence positions in terms of physicochemical properties. The first type of feature uses the evolutionary information combined with the conservation of physicochemical properties of the amino acids while the second reflects the dependency effect of amino acids with regards to polarity charge and hydrophobic properties in the protein sequences. Those two features and an orthogonal binary vector which reflect the characteristics of 20 types of amino acids are used to build the DNABR, a model to predict DNA-binding residues in proteins. The DNABR model achieves a value of 0.6586 for Matthew’s correlation coefficient (MCC) and 93.04 percent overall accuracy (ACC) with a68.47 percent sensitivity (SE) and 98.16 percent specificity (SP), respectively. The comparisons with each feature demonstrate that these two novel features contribute most to the improvement in predictive ability. Furthermore, performance comparisons with other approaches clearly show that DNABR has an excellent prediction performance for detecting binding residues in putative DNA-binding protein. The DNABR web-server system is freely available at http://www.cbi.seu.edu.cn/DNABR/.

  17. A promising RVO4:Eu(3+), Li(+)@SiO2 (R = Gd, Y and Gd/Y) red-emitting phosphor with improved luminescence (cd/m(2)) and colour purity for optical display applications.

    PubMed

    Rambabu, Urlagaddala; Munirathnam, Nagegownivari Ramachandra; Reddy, Busireddy Sudhakar; Chatterjee, Sandip

    2016-02-01

    Red emission intensity was optimized in three stages, by investigating the effects of: (i) host composition (Gd, Y and Gd/Y), (ii) codoping Li(+) as a sensitizer and, finally, (iii) with a SiO2 shell coating as a protecting layer. Lanthanide vanadate powder phosphors were synthesized using a modified colloidal precipitation technique. The effects of SiO2 coating on phosphor particles were characterized using scanning electron microscopy (SEM)-EDAX, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and photoluminescence (PL) measurements. An improvement in the PL intensity on Li codoping was due to improved crystallinity, which led to higher oscillating strengths for the optical transitions, and also a lowering of the inversion symmetry of Eu(3+) ions. Red emission intensity due to (5)D0  → (5)D2 transition of the phosphor Y0.94VO4:Eu(3+)0.05, Li(+)0.01 was enhanced by 22.28% compared with Y0.95VO4:Eu(3+)0.05, and was further improved by 58.73% with SiO2 coating. The luminescence intensity (I) and colour coordinates (x, y) of the optimized phosphor Y0.94VO4:Eu(3+)0.05, Li(+)0.01@SiO2, where I = 13.07 cd/m(2) and (x = 0.6721, y = 0.3240), were compared with values for a commercial red phosphor (Y2O2S:Eu(3+)), where I = 27 cd/m(2) and (x = 0.6522, y = 0.3437). The measured colour coordinates are superior to those of the commercial red phosphor, and moreover, match well with standard NTSC values (x = 0.67, y = 0.33). Copyright © 2015 John Wiley & Sons, Ltd.

  18. Polymeric Materials With Additives for Durability and Radiation Shielding in Space

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard

    2011-01-01

    Polymeric materials are attractive for use in space structures because of their light weight and high strength In addition, polymers are made of elements with low atomic numbers (Z), primarily carbon (C), hydrogen (H), oxygen (0), and nitrogen (N) which provide the best shielding from galactic cosmic rays (GCR) (ref. 1). Galactic cosmic rays are composed primarily of nuclei (i.e., fully ionized atoms) plus a contribution of about 2% from electrons and positrons. There is a small but significant component of GCR particles with high charge (Z > 10) and high energy (E >100 GeV) (ref. 2). These so-called HZE particles comprise only 1 to 2% of the cosmic ray fluence but they interact with very high specific ionization and contribute 50% of the long- term dose to humans. The best shield for this radiation would be liquid hydrogen, which is not feasible. For this reason, hydrogen-containing polymers make the most effective practical shields. Moreover, neutrons are formed in the interactions of GCR particles with materials. Neutrons can only lose energy by collisions or reactions with a nucleus since they are uncharged. This is a process that is much less probable than the Coulombic interactions of charged particles. Thus, neutrons migrate far from the site of the reaction in which they were formed. This increases the probability of neutrons reaching humans or electronic equipment. Fast neutrons (> 1 MeV) can interact with silicon chips in electronic equipment resulting in the production of recoil ions which can cause single event upsets (SEU) in sensitive components (ref. 3). Neutrons lose energy most effectively by elastic collisions with light atoms, particularly hydrogen atoms. Therefore, hydrogen-containing polymers are not only effective in interacting with GCR particles; they are also effective in reducing the energy of the neutrons formed in the interactions.

  19. Fabrication of phosphor micro-grids using proton beam lithography

    NASA Astrophysics Data System (ADS)

    Auzelyte, V.; Elfman, M.; Kristiansson, P.; Pallon, J.; Wegdén, M.; Nilsson, C.; Malmqvist, K.; Doyle, B. L.; Rossi, P.; Hearne, S. J.; Provencio, P. P.; Antolak, A. J.

    2006-01-01

    A new nuclear microscopy technique called ion photon emission microscopy or IPEM was recently invented. IPEM allows analysis involving single ions, such as ion beam induced charge (IBIC) or single event upset (SEU) imaging using a slightly modified optical microscope. The spatial resolution of IPEM is currently limited to more than 10 μm by the scattering and reflection of ion-induced photons, i.e. light blooming or spreading, in the ionoluminescent phosphor layer. We are developing a "Microscopic Gridded Phosphor" (also called Black Matrix) where the phosphor nanocrystals are confined within the gaps of a micrometer scale opaque grid, which limits the amount of detrimental light blooming. MeV-energy proton beam lithography is ideally suited to lithographically form masks for the grid because of high aspect ratio, pattern density and sub-micron resolution of this technique. In brief, the fabrication of the grids was made in the following manner: (1) a MeV proton beam focused to 1.5-2 μm directly fabricated a matrix of pillars in a 15 μm thick SU-8 lithographic resist; (2) 7:1 aspect ratio pillars were then formed by developing the proton exposed area; (3) Ni (Au) was electrochemically deposited onto Cu-coated Si from a sulfamate bath (or buffered CN bath); (4) the SU-8 pillars were removed by chemical etching; finally (5) the metal micro-grid was freed from its substrate by etching the underlying Cu layer. Our proposed metal micro-grids promise an order-of-magnitude improvement in the resolution of IPEM.

  20. Clonal Complexes and Diversity of Exotoxin Gene Profiles in Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Isolates from Patients in a Spanish Hospital▿

    PubMed Central

    Argudín, M. A.; Mendoza, M. C.; Méndez, F. J.; Martín, M. C.; Guerra, B.; Rodicio, M. R.

    2009-01-01

    Molecular epidemiology studies have allowed the identification of the methicillin (meticillin)-resistant (MRSA) and methicillin-susceptible (MSSA) clonal complexes (CCs) and clones of Staphylococcus aureus circulating in a Spanish hospital recently. Of 81 isolates tested, 32.1% were MRSA. Most of them carried staphylococcal cassette chromosome mec (SCCmec) IVc (88.5%) and belonged to CC5 (88.5%; multilocus sequence typing types ST125 [mainly associated with spa type t067], ST5, and ST228). A higher diversity was found among MSSA isolates (67.9%). Eighty percent shared the genetic background of major MRSA lineages (CC5 [38.2%; ST125 and ST5], CC30 [25.5%; ST30], CC45 [14.5%; ST45 and ST47], and CC8 [1.8%; ST8]), but CC12, CC15, CC51, and CC59 were also detected. Many exotoxin genes were present in each of the 81 isolates, independent of whether they were involved in sepsis (11 to 22) or other types of infections (13 to 21), and they appeared in 73 combinations. The relevant data are that (i) all isolates were positive for hemolysin and leukotoxin genes (98.8% for lukED and 25.9% for lukPV); (ii) all contained an enterotoxin gene cluster (egc with or without seu), frequently with one or more genes encoding classical enterotoxins; (iii) about half were positive for tst and 95% were positive for exfoliatin-encoding genes (eta, etb, and/or etd); and (iv) the four agr groups were detected, with agrII (55.6%) and agrIII (23.5%) being the most frequent. Taken together, results of the present study suggest a frequent acquisition and/or loss of exotoxin genes, which may be mediated by efficient intralineage transfer of mobile genetic elements and exotoxin genes therein and by eventual breakage of interlineage barriers. PMID:19458176

  1. [Deep brain stimulation: new frontier in the treatment of CNS disorders].

    PubMed

    Gonçalves Ferreira, Antonio

    2014-01-01

    Introdução: O autor faz uma revisão das indicações atuais da estimulação cerebral profunda, dos seus desenvolvimentos e resultados, dos alvos e técnicas utilizados, dos principais neurocirurgiões e centros médicos envolvidos.Material e Métodos: Esta revisão é baseada na experiência do grupo de Neurocirurgia Funcional do Hospital de Santa Maria (Centro Hospitalar Lisboa Norte) desde 1995 e na revisão bibliográfica dos artigos publicados sobre esta matéria desde 1980 indexados na PubMed.Resultados e Discussão: São apresentadas e discutidas as aplicações da estimulação cerebral profunda nos diferentes domínios das neurociências funcionais: Doenças do Movimento, incluindo doença de Parkinson, distonias e tremores, síndrome de Gilles de la Tourette, dor crónica, epilepsia e psicocirurgia nas múltiplas áreas que esta compreende: perturbação obsessiva-compulsiva, depressão grave refratária, comportamento disruptivo com agressividade intratável, deterioração da memória e demência, perturbações do comportamento alimentar (anorexia nervosa, obesidade mórbida) e toxicodependências refratárias (álcool, opioides, cocaína).Conclusões: Na maioria das situações clínicas referidas a estimulação cerebral profunda constitui um recurso terapêutico seguro e eficaz a ter em consideração quando as terapias habituais se mostram insuficientes; nos restantes casos há que reunir maior experiência até adotar o seu uso regular.

  2. BUSFET - A Novel Radiation-Hardened SOI Transistor

    SciTech Connect

    Schwank, J.R.; Shaneyfelt, M.R.; Draper, B.L.; Dodd, P.E.

    1999-07-20

    The total-dose hardness of SOI technology is limited by radiation-induced charge trapping in gate, field, and SOI buried oxides. Charge trapping in the buried oxide can lead to back-channel leakage and makes hardening SOI transistors more challenging than hardening bulk-silicon transistors. Two avenues for hardening the back-channel are (1) to use specially prepared SOI buried oxides that reduce the net amount of trapped positive charge or (2) to design transistors that are less sensitive to the effects of trapped charge in the buried oxide. In this work, we propose a new partially-depleted SOI transistor structure that we call the BUSFET--Body Under Source FET. The BUSFET utilizes a shallow source and a deep drain. As a result, the silicon depletion region at the back channel caused by radiation-induced charge trapping in the buried oxide does not form a conducting path between source and drain. Thus, the BUSFET structure design can significantly reduce radiation-induced back-channel leakage without using specially prepared buried oxides. Total dose hardness is achieved without degrading the intrinsic SEU and dose rate hardness of SOI technology. The effectiveness of the BUSFET structure for reducing total-dose back-channel leakage depends on several variables, including the top silicon film thickness and doping concentration and the depth of the source. 3-D simulations show that for a doping concentration of 10{sup 18} cm{sup {minus}3} and a source depth of 90 nm, a silicon film thickness of 180 nm is sufficient to almost completely eliminate radiation-induced back-channel leakage. However, for a doping concentration of 3x10{sup 17} cm{sup {minus}3}, a thicker silicon film (300 nm) must be used.

  3. Virtual learning object and environment: a concept analysis.

    PubMed

    Salvador, Pétala Tuani Candido de Oliveira; Bezerril, Manacés Dos Santos; Mariz, Camila Maria Santos; Fernandes, Maria Isabel Domingues; Martins, José Carlos Amado; Santos, Viviane Euzébia Pereira

    2017-01-01

    To analyze the concept of virtual learning object and environment according to Rodgers' evolutionary perspective. Descriptive study with a mixed approach, based on the stages proposed by Rodgers in his concept analysis method. Data collection occurred in August 2015 with the search of dissertations and theses in the Bank of Theses of the Coordination for the Improvement of Higher Education Personnel. Quantitative data were analyzed based on simple descriptive statistics and the concepts through lexicographic analysis with support of the IRAMUTEQ software. The sample was made up of 161 studies. The concept of "virtual learning environment" was presented in 99 (61.5%) studies, whereas the concept of "virtual learning object" was presented in only 15 (9.3%) studies. A virtual learning environment includes several and different types of virtual learning objects in a common pedagogical context. Analisar o conceito de objeto e de ambiente virtual de aprendizagem na perspectiva evolucionária de Rodgers. Estudo descritivo, de abordagem mista, realizado a partir das etapas propostas por Rodgers em seu modelo de análise conceitual. A coleta de dados ocorreu em agosto de 2015 com a busca de dissertações e teses no Banco de Teses e Dissertações da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. Os dados quantitativos foram analisados a partir de estatística descritiva simples e os conceitos pela análise lexicográfica com suporte do IRAMUTEQ. A amostra é constituída de 161 estudos. O conceito de "ambiente virtual de aprendizagem" foi apresentado em 99 (61,5%) estudos, enquanto o de "objeto virtual de aprendizagem" em apenas 15 (9,3%). Concluiu-se que um ambiente virtual de aprendizagem reúne vários e diferentes tipos de objetos virtuais de aprendizagem em um contexto pedagógico comum.

  4. Spincoat-fabricated multilayer PDMS-phosphor composites for thermometry

    NASA Astrophysics Data System (ADS)

    Parajuli, Pratikshya; Allison, Stephen W.; Sabri, Firouzeh

    2017-06-01

    Phosphor thermometry offers unique advantages over traditional forms of temperature sensing. Polymer-encapsulated phosphor powders provide versatility and flexibility not achievable when using the thermographic phosphors in powder form. By encapsulating the powder in a polymeric sleeve custom devices with unique properties can be created. Here, the authors report on the design, synthesis, and characterization of the first multilayer thermographic phosphor structure. A thin layer of neat PDMS, Sylgard 184, was sandwiched between two layers of La2O2S:Eu phosphor-doped PDMS. The thicknesses ranged from 0.15 to 4 mm depending on spin speed. The temperature dependent luminescence of the structure was characterized from  -40 °C to 75 °C, in a low humidity environmental chamber. Results show suitability for thermometry in this range. In addition, for design guidance, quantitative values for thermal conductivity and stress/strain characteristics versus phosphor loading percentage and temperature were measured. Thermal conductivities ranged from 0.15 W mK-1 for the Sylgard 184 to a value between 0.3 and 0.4 W mK-1 for pure phosphor powder for temperatures from  -55 °C to 195 °C. Tensile properties for a strain of up to 1 revealed differences between the different phosphor loadings and phosphor batches. Young’s modulus for the spincoat layered materials was between 1.2 and 1.4 N mm-2 and 0.8 for drop casted samples.

  5. The magnitude and effects of extreme solar particle events

    NASA Astrophysics Data System (ADS)

    Jiggens, Piers; Chavy-Macdonald, Marc-Andre; Santin, Giovanni; Menicucci, Alessandra; Evans, Hugh; Hilgers, Alain

    2014-06-01

    The solar energetic particle (SEP) radiation environment is an important consideration for spacecraft design, spacecraft mission planning and human spaceflight. Herein is presented an investigation into the likely severity of effects of a very large Solar Particle Event (SPE) on technology and humans in space. Fluences for SPEs derived using statistical models are compared to historical SPEs to verify their appropriateness for use in the analysis which follows. By combining environment tools with tools to model effects behind varying layers of spacecraft shielding it is possible to predict what impact a large SPE would be likely to have on a spacecraft in Near-Earth interplanetary space or geostationary Earth orbit. Also presented is a comparison of results generated using the traditional method of inputting the environment spectra, determined using a statistical model, into effects tools and a new method developed as part of the ESA SEPEM Project allowing for the creation of an effect time series on which statistics, previously applied to the flux data, can be run directly. The SPE environment spectra is determined and presented as energy integrated proton fluence (cm-2) as a function of particle energy (in MeV). This is input into the SHIELDOSE-2, MULASSIS, NIEL, GRAS and SEU effects tools to provide the output results. In the case of the new method for analysis, the flux time series is fed directly into the MULASSIS and GEMAT tools integrated into the SEPEM system. The output effect quantities include total ionising dose (in rads), non-ionising energy loss (MeV g-1), single event upsets (upsets/bit) and the dose in humans compared to established limits for stochastic (or cancer-causing) effects and tissue reactions (such as acute radiation sickness) in humans given in grey-equivalent and sieverts respectively.

  6. On Ensino de Astronomia: Desafios para Implantação

    NASA Astrophysics Data System (ADS)

    Faria, R. Z.; Voelzke, M. R.

    2008-09-01

    Em 2002 o ensino de Astronomia foi proposto como um dos temas estruturadores pelos Parâmetros Curriculares Nacionais e sugerido como facilitador para que o aluno compreendesse a Física como construção humana e parte do seu mundo vivencial, mas raramente seus conceitos foram ensinados. A presente pesquisa discute dois aspectos relacionados à abordagem de Astronomia. O primeiro aspecto é se ela está sendo abordada pelos professores do Ensino Médio e o segundo, aborda a maneira como ela está sendo ensinada. Optou-se pela aplicação de um questionário a partir do 2° semestre de 2006 e durante o ano de 2007 com professores que ministram a disciplina de Física, os quais trabalham em escolas estaduais em Rio Grande da Serra, Ribeirão Pires e Mauá no estado São Paulo. Dos 66,2% dos professores que responderam ao questionário nos municípios de Rio Grande da Serra, Ribeirão Pires e Mauá, 57,4% não aplicaram nenhum tópico de astronomia, 70,2% não utilizaram laboratório, 89,4% não utilizaram qualquer tipo de programa computacional, 83,0% nunca fizeram visitas com alunos a museus e planetários e 38,3% não indicaram qualquer tipo de livro ou revista referente à astronomia aos seus alunos. Mesmo considerando a Astronomia um conteúdo potencialmente significativo, esta não fez parte dos planejamentos escolares. Portanto são necessárias propostas que visem estratégias para a educação continuada dos professores como, por exemplo, cursos específicos sobre o ensino em Astronomia.

  7. Treatment of retroauricular keloids: Revision of cases treated at the ENT service of HC/UFPR.

    PubMed

    Carvalho, Bettina; Ballin, Annelyse Cristine; Becker, Renata Vecentin; Ribeiro, Talita Beithum; Cavichiolo, Juliana Benthien; Ballin, Carlos Roberto; Mocellin, Marcos

    2012-04-01

    Introdução: Queloides são tumores benignos resultantes de cicatrização anômala da pele, sendo que existem diversos procedimentos disponíveis para o seu tratamento.Objetivo: O objetivo deste trabalho é avaliar os resultados de pacientes submetidos a tratamento de queloides retroauriculares após cirurgias otorrinológicas em nosso serviço.Método: Estudo retrospectivo e prospectivo, através de análise de prontuários, dos pacientes submetidos a tratamento de queloides retroauriculares em nosso serviço.Resultados: Nove pacientes foram avaliados, sendo que 6 foram submetidos a ressecção e betaterapia adjuvante, 2 foram submetidos a ressecção mais aplicação de corticoide local, 1 foi submetido apenas a ressecção sem terapia adjuvante. Não houve recidiva nos casos tratados com betaterapia no pós-operatório precoce, 1 paciente apresentou recidiva mesmo com corticoterapia e betaterapia tardia.Discussão: diversas técnicas tem sido utilizadas para tratamento dos queloides retroauriculares, sendo que a betaterapia é considerada a com melhores resultados, seguida pela utilização de corticoides intralesionais.Conclusão: o tratamento dos queloides retroauriculares continua um desafio. Enquanto novas técnicas não são desenvolvidas, a ressecção seguida de betaterapia precoce ainda é a melhor opção.

  8. [Esophageal perforation in children: a review of one pediatric surgery institution's experience (16 years)].

    PubMed

    Vieira, Elizabete; Cabral, Maria João; Gonçalves, Mroslava

    2013-01-01

    Introdução: O estudo teve por objetivo avaliar a experiência do nosso Serviço no tratamento das perfurações esofágicas. Material e Métodos: Análise retrospetiva de nove casos ocorridos entre 1 de Janeiro de 1996 e 31 de Dezembro de 2011. Destes casos, sete ocorreram após ingestão acidental de corpos estranhos e em dois tratou-se de lesões iatrogénicas após dilatação esofágica: por estenose péptica num caso e no outro por estenose da anastomose esofágica término-terminal de uma criança operada por atrésia do esófago. Resultados: Em 78% dos casos a abordagem inicial foi médica, com encerramento comprovado da perfuração em média ao fim de 20 dias; 22% dos doentes (dois casos) foram submetidos a cirurgia sem sucesso, acabando um deles por curar sem sequelas com pausa alimentar e terapêutica médica; no outro caso verificou-se necessidade de realizar posteriormente uma esofagocoloplastia. Na nossa série não se registou mortalidade. Discussão: A perfuração esofágica é uma das lesões mais graves do trato alimentar, continuando a ser devastadora, e, de difícil diagnóstico e tratamento. O reconhecimento desta complicação é fundamental para o seu tratamento com sucesso. Conclusões: O atraso do diagnóstico está associado a uma mortalidade que pode oscilar entre os 20 e 40%.

  9. Mars Express and Venus Express Data Retention In-Flight Performance

    NASA Astrophysics Data System (ADS)

    Lebrédonchel, J.; Rombeck, F.-J.

    2007-08-01

    Venus, Mars and Earth, three out of the four inner or 'rocky' planets of the Solar System, have a lot in common: a solid surface you could walk on, a comparable surface composition, an atmosphere and a weather system. European Space Agency (ESA) Mars Express (MEx) and Venus Express (VEx) pioneer scientific missions aim at exploring these two neighbours of the Earth, in order to enrich our knowledge of our planet and of the Solar System. Both projects are based on the same spacecraft bus, and in particular on 'sister' Solid State Mass Memory (SSMM) units, in charge of the acquisition, storage and retrieval of all on board data, relevant both to the platform and to the instruments. This paper recalls the common SSMM design and the inner fault tolerant memory array module architecture based on Computer Off The Shelf (COTS) Samsung 64 Mbit Synchronous Dynamic Random Access Memory (SDRAM) chips, and presents the comparative in-flight data retention performance for both MEx and Vex units, since their respective June 2003 and November 2005 launches. Both units have shown to successfully withstand the radiative deep space environment, including during the outstanding October 2003 solar flare, and no uncorrectable data corruption was ever reported. Beyond this stable retention performance over time, the memory scrubbing correctable error accounting feedback allows evaluating the deep space Single Event Upset (SEU) rates, to be compared with the theoretical SSMM radiation assessment as well as with other previous missions in-flight qualitative reference performance records, and finally enables to derive a couple of recommendations from the lessons' learnt.

  10. Single Event Effects Test Facility Options at the Oak Ridge National Laboratory

    SciTech Connect

    Riemer, Bernie; Gallmeier, Franz X; Dominik, Laura J

    2015-01-01

    Increasing use of microelectronics of ever diminishing feature size in avionics systems has led to a growing Single Event Effects (SEE) susceptibility arising from the highly ionizing interactions of cosmic rays and solar particles. Single event effects caused by atmospheric radiation have been recognized in recent years as a design issue for avionics equipment and systems. To ensure a system meets all its safety and reliability requirements, SEE induced upsets and potential system failures need to be considered, including testing of the components and systems in a neutron beam. Testing of integrated circuits (ICs) and systems for use in radiation environments requires the utilization of highly advanced laboratory facilities that can run evaluations on microcircuits for the effects of radiation. This paper provides a background of the atmospheric radiation phenomenon and the resulting single event effects, including single event upset (SEU) and latch up conditions. A study investigating requirements for future single event effect irradiation test facilities and developing options at the Spallation Neutron Source (SNS) is summarized. The relatively new SNS with its 1.0 GeV proton beam, typical operation of 5000 h per year, expertise in spallation neutron sources, user program infrastructure, and decades of useful life ahead is well suited for hosting a world-class SEE test facility in North America. Emphasis was put on testing of large avionics systems while still providing tunable high flux irradiation conditions for component tests. Makers of ground-based systems would also be served well by these facilities. Three options are described; the most capable, flexible, and highest-test-capacity option is a new stand-alone target station using about one kW of proton beam power on a gas-cooled tungsten target, with dual test enclosures. Less expensive options are also described.

  11. Synthesis and Crystal Structure Study of 2’-Se-Adenosine-Derivatized DNA

    SciTech Connect

    Sheng, J.; Salon, J; Gan, J; Huang, Z

    2010-01-01

    The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic acids. Selenium can serve as an excellent anomalous scattering center to solve the phase problem, which is one of the two major bottlenecks in macromolecule X-ray crystallography. The other major bottleneck is crystallization. It has been demonstrated that the incorporated selenium functionality at the 2'-positions of the nucleosides and nucleotides is stable and does not cause significant structure perturbation. Furthermore, it was observed that the 2'-Se-derivatization could facilitate crystallization of oligonucleotides with fast crystal growth and high diffraction quality. Herein, we describe a convenient synthesis of the 2'-Se-adenosine phosphoramidite, and report the first synthesis and X-ray crystal structure determination of the DNA containing the 2'-Se-A derivatization. The 3D structure of 2'-Se-A-DNA decamer [5'-GTACGCGT(2'-Se-A)C-3']{sub 2} was determined at 1.75 {angstrom} resolution, the 2'-Se-functionality points to the minor groove, and the Se-modified and native structures are virtually identical. Moreover, we have observed that the 2'-Se-A modification can greatly facilitate the crystal growth with high diffraction quality. In conjunction with the crystallization facilitation by the 2'-Se-U and 2'-Se-T, this novel observation on the 2'-Se-A functionality suggests that the 2'-Se moiety is sole responsible for the crystallization facilitation and the identity of nucleobases does not influence the crystal growth significantly.

  12. [Richard Morton (1637-1698)--the distinguished physician of the 17th century].

    PubMed

    Kontić, Olga; Vasiljević, Nadja; Jorga, Jagoda; Lakić, Aneta; Jasović-Gasić, Miroslava

    2009-01-01

    Richard Morton was a distinguished physician of the 17th century. He was born in Suffolk, England, on July 30th 1637. Morton published three works but his landmark paper was "Phthisiologia, seu exercitationes de phthisi, tribus libris comprehensae" published in 1689, dedicated to William III. The book established his reputation at home and abroad lasting for over a century. Pulmonary tuberculosis was very frequent in the 17th century in England. He was the first physician ever to state that tubercles were always present in its pulmonary form. When we add to these momentous observations and their rational explanation the facts that he was the first physician to state categorically that tubercles are always present in phthisis, we must agree that Morton richly deserves his honoured place in the long list of those who have contributed to the solution of the problem of tuberculosis. Morton first described and gave conclusions of numerous today well known and already examined illnesses. In 1694 he gave first notes about the psychiatric illness which we today call "anorexia nervosa", calling it "nervous consumption". His chapters on treatment are long and contain a sound basis of common sense as indicated by his instructions on general management. He stresses the need for an adequate diet, an environment free from fog and smoke, and the desirability of ensuring a moderate amount of exercise. All Morton's therapeutic dicta are in their humanity and thoughtful care in striking contrast to the regimen of copious bleeding and semi-starvation inflicted by the later generation of physicians. Confirmation of his achievements and his teaching can be found in today's medical practice.

  13. A eficiência de formação estelar em Musca

    NASA Astrophysics Data System (ADS)

    Hickel, G. R.; Vilas-Boas, J. W. S.; Roberto, A. J.., Jr.; Khan, R. P.

    2003-08-01

    Apresentamos os resultados de um survey no infravermelho próximo (bandas J e H), executado no Laboratório Nacional de Astrofísica, na direção da nuvem escura em forma de filamento de Musca (observamos ao longo de todo o filamento, além de todas as fontes pontuais IRAS e/ou fontes ROSAT brilhantes a uma distância de 2o da nuvem). Nosso objetivo é determinar a eficiência de formação estelar para esta nuvem escura (massa de estrelas formadas/massa da nuvem), procurando por objetos estelares jovens de pequena massa no seu interior e/ou evoluídos o suficiente para estarem afastados do local de nascimento, mas ainda mostrando características de objetos pré-seqüência principal como emissão de raios-X e excesso de emissão no infravermelho próximo. Este survey não estabeleceu nenhum viés na seleção de fontes pontuais IRAS ou fontes ROSAT, uma vez que a imensa maioria das fontes pontuais IRAS nesta região têm qualidade de fluxo ruim. Os candidatos a objetos estelares jovens foram selecionados pelo excesso no índice de cor (J-H), descontados os efeitos da extinção interestelar na linha de visada, determinada através da emissão estendida no infravermelho distante (IRAS). Estimativas de massa foram feitas para estes candidatos, através da relação massa-luminosidade, para calcular a eficiência de formação estelar de Musca.

  14. Splenic artery aneurysm.

    PubMed

    Tcbc-Rj, Rui Antônio Ferreira; Ferreira, Myriam Christina Lopes; Ferreira, Daniel Antônio Lopes; Ferreira, André Gustavo Lopes; Ramos, Flávia Oliveira

    2016-01-01

    Splenic artery aneurysms - the most common visceral artery aneurysms - are found most often in multiparous women and in patients with portal hypertension. Indications for treatment of splenic artery aneurysm or pseudoaneurysm include specific symptoms, female gender and childbearing age, presence of portal hypertension, planned liver transplantation, a pseudoaneurysm of any size, and an aneurysm with a diameter of more than 2.5cm. Historically, the treatment of splenic artery aneurysm has been surgical ligation of the splenic artery, ligation of the aneurysm, or aneurysmectomy with or without splenectomy, depending on the aneurysm location. There are other percutaneous interventional techniques. The authors present a case of a splenic artery aneurysm in a 51-year-old woman, detected incidentally. RESUMO Aneurismas da artéria esplênica - os aneurismas arteriais viscerais mais comuns - são encontrados mais frequentemente em mulheres multíparas e em pacientes com hipertensão portal. As indicações para o seu tratamento incluem sintomas específicos, sexo feminino e idade fértil, presença de hipertensão portal, paciente em fila de transplante hepático, um pseudoaneurisma de qualquer tamanho, e um aneurisma com um diâmetro superior a 2,5cm. Historicamente, o tratamento do aneurisma da artéria esplênica tem sido a ligadura cirúrgica da artéria esplênica, a ligadura do aneurisma ou a aneurismectomia, com ou sem esplenectomia, dependendo do local do aneurisma. Existem outras técnicas intervencionistas percutâneas. Os autores apresentam o caso de um aneurisma de artéria esplênica em uma mulher de 51 anos de idade, diagnosticado incidentalmente.

  15. Simulação de ejeções de massa coronal

    NASA Astrophysics Data System (ADS)

    Corsini, M. A.; Silva, A. V. R.

    2003-08-01

    Ejeções de massa coronal (EMC) são bolhas gigantes de gás permeadas por campos magnéticos que são ejetadas do Sol durante um período de várias horas. Caso estas ejeções atinjam a Terra, geralmente, causam uma série de distúrbios às comunicações de longa distância e navegação, além de danos a satélites e transformadores. Portanto, é desejável que sejamos capazes de prever quando estas ejeções atingirão a Terra. Para tanto, é necessário um bom entendimento dos mecanismos causadores das ejeções e, principalmente, de como se dá a propagação das EMC e sua interação com o vento solar que permeia o meio interplanetário. Nesse sentido foi desenvolvido um programa computacional para resolver as equações MHD (Magneto-Hidro-Dinâmica) que regem a evolução das EMC. Primeiramente foram estabelecidas as condições necessárias para descrever o vento solar, no estado estacionário, que permeia todo o meio interplanetário. Num primeiro momento, resolveu-se o sistema de equações para o caso do vento isotérmico, conhecida como a solução de Parker, a fim de testarmos o modelo. Então, foi considerado o caso do vento solar com temperatura variável no meio interplanetário. Este resultado foi utilizado como a base de nosso sistema em seu instante inicial. Posteriormente foram feitas as considerações necessárias para descrever a propagação da Ejeção de Massa Coronal. As EMC foram simuladas como um aumento de densidade e temperatura local na coroa solar. A órbita e a posição da Terra foram incluídas no sistema. Os dados gerados possibilitaram uma análise da evolução da EMC pelo meio interplanetário até encontrar-se com a Terra. Os perfis de densidade e temperatura a 1 Unidade Astronômica são comparados com os dados de satélites reportados na literatura.

  16. [Weight control attempts among Portuguese adults: prevalence, motives and behavioral strategies].

    PubMed

    Santos, Inês; Andrade, Ana M; Teixeira, Pedro J

    2015-01-01

    Introdução: Em Portugal não existem dados atuais sobre tentativas de controlo do peso nem sobre estratégias e motivos na base dessas tentativas na população. Este estudo teve como objectivos determinar a prevalência das tentativas de perda/manutenção do peso e identificar as estratégias comportamentais e os motivos associados, numa amostra representativa da população adulta portuguesa. Material e Métodos: Estudo transversal constituído por 1098 indivíduos adultos. A informação sociodemográfica, os dados antropométricos e as estratégias e motivos associados à perda/manutenção do peso foram recolhidos por entrevista telefónica. Resultados: Cerca de 44% dos adultos portugueses (53% de mulheres e 35% dos homens) estão ativamente a tentar controlar o peso. Salienta-se que 22% das mulheres com peso normal tentam perder peso e que 53% dos homens e 34% das mulheres com peso excessivo não o fazem. Entre os homens, 49% com nível educacional superior estão a tentar controlar o peso versus 32% com nível educacional básico. A estratégia mais frequentemente adoptada para gerir o peso é o consumo regular de hortícolas e os motivos mais referenciados são melhorar a saúde/prevenir doenças e melhorar o bem-estar. Discussão e Conclusão: Mais de metade das mulheres e cerca de um terço dos homens em Portugal estão ativamente a tentar gerir o seu peso, utilizando estratégias comportamentais consistentes com as recomendações de saúde pública. Os motivos de saúde e bem-estar predominam sobre os restantes. Este estudo contribui para o conhecimento da gestão do peso em Portugal, alertando para o desenvolvimento de estratégias de prevenção da obesidade adequadas ao perfil da população.

  17. Modelagem do vento e da fotosfera de AG Carinae

    NASA Astrophysics Data System (ADS)

    Groh, J. H.; Damineli, A.

    2003-08-01

    A trajetória evolutiva das estrelas de alta massa depende fortemente de suas taxas de perda de massa. Apesar do rápido progresso no estudo destas estrelas, a taxa de perda de massa e outros parâmetros físicos básicos, como a temperatura superficial e a velocidade terminal do vento ainda não estão bem determinados. Isto ocorre devido à presença de ventos irregulares, rápidos e fortes ao redor destas estrelas, tornando a interpretação dos seus espectros uma tarefa difícil. Assim, a modelagem do vento e da fotosfera dessas estrelas está sendo cada vez mais usada para obter tais parâmetros a partir dos espectros. O aumento da taxa de perda de massa durante a fase LBV (Variáveis Luminosas Azuis), comparado com outros tipos de estrelas, tem sido atribuído a instabilidades do tipo S Doradus. Dispomos de uma base de dados espectroscópicos cobrindo 22 anos de observações de AG Carinae, incluindo um ciclo S Doradus completo, com espectros CCD em alta resolução na faixa óptica e infravermelha. Utilizamos o programa desenvolvido por Schmutz (1997) para uma análise preliminar desse ciclo, obtendo a taxa de perda de massa a partir da linha do Ha. Não existe uma correlação clara da taxa de perda de massa com mudanças da temperatura efetiva, do raio da estrela e do fluxo na banda V. A estrela atingiu seu mínimo fotométrico (raio mínimo) em 1990 e o máximo fotométrico (raio máximo) em 1995, enquanto que o fluxo máximo da linha do Ha ocorreu em 1996. Além disso a taxa de perda de massa não segue esse ciclo, contrariamente às idéias correntes. Para fazer um modelo mais realista estamos usando o programa CMFGEN (Hillier & Miller), que trata a fotosfera e o vento estelar de forma consistente, considerando a radiação fora do equilíbrio termodinâmico (NLTE) e com blanketting total de linhas. Simulamos o espectro de AG Carinae em duas épocas extremas do ciclo S Dor para testar os resultados obtidos com o modelo mais simplificado.

  18. Camões e a cosmogonia

    NASA Astrophysics Data System (ADS)

    Costa, J. M.

    2003-08-01

    Os Lusíadas, escrito por Luis de Camões em 1572, é um poema épico renascentista e a visão Cosmogônica do autor é apresentada, principalmente, no último canto do poema, quando Tétis mostra ao Gama a Máquina do Mundo. A Cosmogonia de Camões neste poema reflete uma visão de uma época de transição, que ainda não incorporou os elementos da revolução Copernicana. É uma visão Grego- Ptolomaica e também medieval. O poeta guia-se pela tradução e notas feita por Pedro Nunes, inventor do Nonio, do Tratado da Esfera "De Sphaera" do Astrônomo Inglês John Holywood, mais conhecido pelo nome latinizado de Johannes Sacrobosco. Outra provável fonte de Camões, de acordo com Luciano Antonio Pereira da Silva em Astronomia de os Lusíadas, é o "Theoricae novae Planetarum" (1460) do astrólogo Alemão Jorge Purbáquio (1423 - 1461). A Astronomia de Os Lusíadas representa a ciência do tempo de Camões. Camões nunca emprega a palavra constelação e seu catálogo é bastante completo. A Máquina do Mundo tem a Terra no centro. Em redor, em círculos concêntricos, a lua (Diana), Mercúrio, Vênus, o Sol (Febo), Marte, Júpiter e Saturno. Envolvendo estes astros tem o firmamento seguido pelo "Céu Áqueo" ou cristalino, depois o 1o Móbil, esfera que arrasta todas as outras consigo. Este trabalho, multidisciplinar, serve tanto para ensinar aos alunos da Física como das Ciências Humanas, a concepção de mundo do renascimento de uma forma belamente poética em versos decassílabos Este trabalho também ajuda na apreciação do maior clássico da língua portuguesa e mostra como as Ciências e as artes, em geral, estão correlacionadas e refletem a visão de mundo da época em que foi produzida.

  19. Sexual Dysfunction in Breast Cancer Survivors: Cross-Cultural Adaptation of the Sexual Activity Questionnaire for Use in Portugal.

    PubMed

    da Costa, Filipa Alves; Ribeiro, Manuel Castro; Braga, Sofia; Carvalho, Elisabete; Francisco, Fátima; Miranda, Ana Costa; Moreira, António; Fallowfield, Lesley

    2016-09-01

    Introdução: A crescente população de sobreviventes de cancro da mama tem redireccionado o interesse investigacional e prático para o impacto da doença e do seu tratamento nas várias áreas da qualidade de vida. A falta de questionários para avaliar de forma objectiva a disfunção sexual conduziu à necessidade de adaptar e validar culturalmente o Sexual Activity Questionnaire para utilização em Portugal. Material e Métodos: O Sexual Activity Questionnaire foi traduzido e retrovertido, sua versão de consenso refinada após teste de compreensão, e subsequentemente auto-administrado a uma amostra alargada de sobreviventes de cancro da mama em dois momentos, espaçados 15 dias, para julgar a sua validade e fiabilidade. Resultados: Após alterações minor à versão de consenso, o Sexual Activity Questionnaire foi aplicado a 134 doentes. Obteve-se uma estrutura de três factores (75,5% da variância), compreendendo as escalas do Prazer, Hábito e Desconforto, todas com boa consistência interna (α de Cronbach > 0,70), boa validade concorrente com o FACt-An e a checklist BCPT (r de Spearman > 0,65; p-value < 0,001) e estabilidade temporal aceitável (k de Cohen > 0,44). Foi identificada inactividade sexual em 23,9% das mulheres, devido a falta de interesse ou ao facto de não ter parceiro. Discussão: Os dados reportados pelos doentes conduziram a alterações nos cuidados prestados, que passaram a contemplar a oncosexologia. Estudos futuros deverão focar-se na aplicabilidade deste questionário a amostras com diferentes características e mesmo à população global, para se poderem generalizar os resultados. Conclusão: A versão obtida do Sexual Activity Questionnaire é válida para avaliar a função sexual em sobreviventes de cancro da mama em Portugal.

  20. Cardiac Regeneration using Growth Factors: Advances and Challenges.

    PubMed

    Rebouças, Juliana de Souza; Santos-Magalhães, Nereide Stela; Formiga, Fabio Rocha

    2016-09-01

    Myocardial infarction is the most significant manifestation of ischemic heart disease and is associated with high morbidity and mortality. Novel strategies targeting at regenerating the injured myocardium have been investigated, including gene therapy, cell therapy, and the use of growth factors. Growth factor therapy has aroused interest in cardiovascular medicine because of the regeneration mechanisms induced by these biomolecules, including angiogenesis, extracellular matrix remodeling, cardiomyocyte proliferation, stem-cell recruitment, and others. Together, these mechanisms promote myocardial repair and improvement of the cardiac function. This review aims to address the strategic role of growth factor therapy in cardiac regeneration, considering its innovative and multifactorial character in myocardial repair after ischemic injury. Different issues will be discussed, with emphasis on the regeneration mechanisms as a potential therapeutic resource mediated by growth factors, and the challenges to make these proteins therapeutically viable in the field of cardiology and regenerative medicine. Resumo O infarto do miocárdio representa a manifestação mais significativa da cardiopatia isquêmica e está associado a elevada morbimortalidade. Novas estratégias vêm sendo investigadas com o intuito de regenerar o miocárdio lesionado, incluindo a terapia gênica, a terapia celular e a utilização de fatores de crescimento. A terapia com fatores de crescimento despertou interesse em medicina cardiovascular, devido aos mecanismos de regeneração induzidos por essas biomoléculas, incluindo angiogênese, remodelamento da matriz extracelular, proliferação de cardiomiócitos e recrutamento de células-tronco, dentre outros. Em conjunto, tais mecanismos promovem a reparação do miocárdio e a melhora da função cardíaca. Esta revisão pretende abordar o papel estratégico da terapia, com fatores de crescimento, para a regeneração cardíaca, considerando seu car