WorldWideScience
 
 
1

Development of multi-layer thin film bolometer with fast time response and high sensitivity  

International Nuclear Information System (INIS)

[en] Impurity radiation loss is one of major cooling mechanisms in a fusion plasma. A multi-layer thin film bolometer with high sensitivity and fast time response has been developed for the measurement of radiation energy loss of a screw pinch plasma in TPE-2 device. The construction and test of the bolometer are described. High sensitivity of 2.5 mV/? Joule and fast time response of 10 ?sec with cooling time of 50 msec are obtained. (author)

1985-01-01

2

Time response of fast-gated microchannel plates used as x-ray detectors  

Energy Technology Data Exchange (ETDEWEB)

We report measurements of the time response of fast-gated, micro- channel plate (MCP) detectors, using a <10 ps pulsewidth ultra-violet laser and an electronic sampling system to measure time resolutions to better than 25 ps. The results show that framing times of less than 100 ps are attainable with high gain. The data is compared to a Monte Carlo calculation, which shows good agreement. We also measured the relative sensitivity as a function of DC bias, and saturation effects for large signal inputs. In part B, we briefly describe an electrical time-of-flight'' technique, which we have used to measure the response time of a fast-gated microchannel plate (MCP). Thinner MCP's than previously used have been tested, and, as expected, show fast gating times and smaller electron multiplication. A preliminary design for an x-ray pinhole camera, using a thin MCP, is presented. 7 refs., 6 figs.

Turner, R.E.; Bell, P.; Hanks, R.; Kilkenny, J.D.; Landen, N.; Power, G.; Wiedwald, J.; Meier, M.

1990-11-05

3

Ultra-Fast Flash Observatory: Fast Response Space Missions for Early Time Phase of Gamma Ray Bursts  

DEFF Research Database (Denmark)

One of the unexplored domains in the study of gamma-ray bursts (GRBs) is the early time phase of the optical light curve. We have proposed Ultra-Fast Flash Observatory (UFFO) to address this question through extraordinary opportunities presented by a series of small space missions. The UFFO is equipped with a fast-response Slewing Mirror Telescope that uses a rapidly moving mirror or mirror array to redirect the optical beam rather than slewing the entire spacecraft or telescope to aim the optical instrument at the GRB position. The UFFO will probe the early optical rise of GRBs with sub-second response, for the first time, opening a completely new frontier in GRB and transient studies. Its fast response measurements of the optical emission of dozens of GRB each year will provide unique probes of the burst mechanism and test the prospect of GRB as a new standard candle, potentially opening up the z > 10 universe. We describe the current limit in early photon measurements, the aspects of early photon physics, our soon-to-be-launched UFFO-pathfinder mission, and our next planned mission, the UFFO-100.

Park, I.H.; Ahmad, S.

2013-01-01

4

Polymer-stabilized liquid crystal microlens array with large dynamic range and fast response time.  

UK PubMed Central (United Kingdom)

We report a polymer-stabilized liquid crystal (LC) microlens array with a large dynamic range and fast response time. The top substrate has a planar indium-tin oxide (ITO) electrode, while the bottom substrate has two patterned ITO electrodes for generating a fringing field and uniform longitudinal field. The fringing field is utilized to create the desired gradient refractive index profile in the LC/monomer layer, which is later stabilized by UV curing to form polymer networks. To tune the focal length, we apply a longitudinal field to change the lens shape. This microlens array offers several attractive features, such as large dynamic range, fast response time, and good mechanical stability.

Ren H; Xu S; Wu ST

2013-08-01

5

Variable optical attenuator using thermo-optic two-mode interference device with fast response time.  

UK PubMed Central (United Kingdom)

A thermo-optic two-mode interference (TMI) waveguide structure with a silicon trench and heat-insulating grooves in both sides of the core has been proposed for a variable optical attenuator (VOA) with fast response time. Thermal analysis of the proposed thermo-optic TMI waveguide structure with a silicon oxinitride (SiON) core has been performed by using the implicit finite difference method. The heating power required to achieve the attenuated power of approximately -25.5 dB for a VOA with a silicon trench is 460 mW , which is approximately 1.8 times less than that of a VOA without a silicon trench. The response time is estimated as approximately 98 micros, which is faster than the response time of the existing VOA.

Sahu PP

2009-07-01

6

Mechanism and echo time dependence of the fast response in fMR.  

UK PubMed Central (United Kingdom)

The fast response (FR) is an early reduction in the amplitude of the fMR signal occurring shortly after the onset of stimulation. Owing to its potential advantages in terms of temporal and spatial resolution, it may be of considerable significance in functional experiments. A model for the mechanism of the FR was developed which accounts for the fMRS finding that the amplitude of the dip decreases with increasing echo time. Two computer simulations that confirmed the predictions of the model and showed that it is possible to select optimal echo times for the detection of the FR were performed.

Dymond RC; Norris DG

1997-07-01

7

Timing and fast control  

CERN Document Server

Abstract -------- In this paper we discuss the current understanding of the design of the LHCb Timing and Fast Control (TFC) system. In view of the fact that there exists some infrastructure for a TFC in the form of the RD-12 TTC system we focus on the applicability of this system to the LHCb TFC, subject to the special LHCb requirements imposed by the LHCb two-level trigger architecture. We conclude that the RD-12 system can be used for our application, but that we have to build a few modules to support our high Level-0 accept rate (Readout Supervisor) and to support the requirement of partitioning (Switch). We expect no major problems in implementing both modules.

Jost, B

1999-01-01

8

Time dependent aspects of the response of some avalanche photoidodes to fast neutron irradiation  

Energy Technology Data Exchange (ETDEWEB)

Using the fast neutron flux available from the beam collector on the RAL spallation neutron source (ISIS) we have irradiated the two types of avalanche photodiodes (APD) {l_brace}Hamamatsu S5345 (high capacitance) and the EG and G C30626E{r_brace} up to a maximum fluence of 2 x 10{sup 13} neutrons per cm{sup 2}. We report the recovery behaviour of the device dark currents and noise characteristics following exposure to the neutron flux. Using the parameters derived from these observations we model the evolution of the dark current and noise through likely CMS activity schedules. (author).

Bateman, J.E.; Stephenson, R.

1996-04-01

9

Time dependent aspects of the response of some avalanche photodiodes to fast neutron irradiation. Technical report  

Energy Technology Data Exchange (ETDEWEB)

Using the fast neutron flux available from the beam collector on the RAL spallation neutron source (ISI) the authors have irradiated the two types of avalanche photodiodes (APD) (Hamamatus S5345 (high capacitance) and the EG&G C30626E) up to a maximum fluence of 2 X 10(exp 13) neutrons per sq.cm. They report the recovery behavior of the device dark currents and noise characteristics following exposure to the neutron flux. Using the parameters derived from these observations they model the evolution of the dark current and noise through likely CMS activity schedules.

Bateman, J.E.; Stephenson, R.

1996-04-01

10

Fast-response signal upconversion by the use of a ``time-space conversion'' method  

Science.gov (United States)

Lanthanide-doped phosphors achieve signal wavelength conversion between visible and infrared communication systems. A long lifetime of their excited states is advantageous for inducing two-photon absorption that realizes upconversion. The long lifetime, however, restricts the conversion rate to ~500 bit/s because of the afterglow. This contradiction was solved by embedding a phosphor (YbEr:Gd2O2S) in a rotating disk. When an infrared (940 nm) pulse train of 1 Mbit/s (time domain) was focused on the disk, a fluorescent dot array (space domain) was created and moved with the disk rotation. Consequently, a visible (~550 nm) pulse train was detected on the dot trajectory.

Saito, Mitsunori; Nakamura, Shingo; Kita, Teppei

2011-11-01

11

Fast response liquid crystal devices  

Science.gov (United States)

Liquid crystal (LC) has been widely used for displays, spatial light modulators, variable optical attenuators (VOAs) and other tunable photonic devices. The response time of these devices is mainly determined by the employed liquid crystal material. The response time of a LC device depends on the visco-elastic coefficient (gamma1/K11), LC cell gap (d), and applied voltage. Hence, low visco-elastic coefficient LC materials and thinner cell gap are favorable for reducing the response time. However, low visco-elastic coefficient LCs are usually associated with a low birefringence because of shorter molecular conjugation. For display applications, such as LCD TVs, low birefringence (Deltan<0.1) LCs are commonly used. However, for optical communications at 1550 nm, low birefringence requires to a thick cell gap which, in turn, increases the response time. How to obtain fast response for the LC devices is a fundamentally important and technically challenging task. In this dissertation, we investigate several methods to improve liquid crystal response time, for examples, using dual-frequency liquid crystals, polymer stabilized liquid crystals, and sheared polymer network liquid crystals. We discover a new class of material, denoted as sheared polymer network liquid crystal (SPNLC) which exhibits a submillisecond response time. Moreover, this response time is insensitive to the LC cell gap. This is the first LC device exhibiting such an interesting property. Chapters 1 and 2 describe the motivation and background of this dissertation. From chapter 3 to chapter 6, dual-frequency liquid crystals and polymer network methods are demonstrated as examples for the variable optical attenuators. Variable optical attenuator (VOA) is a key component in optical communications. Especially, the sheared PNLC VOA shows the best result; its dynamic range reaches 43 dB while the response time is in the submillisecond range at 1550 nm wavelength, which is 50 times faster than the commercial LC-based VOA. In Chapter 7, we report a new device called axially-symmetric sheared polymer network liquid crystals (AS-SPNLC) and use it as LC devices. Through analyzing the structure of this axially-symmetric SPNLC, we construct a 3-D model to explain the observed phenomena. An axially-symmetric sheared polymer network liquid crystal has several attractive features: (1) it is polarization independent, (2) it has gradient phase change, and (3) its response time is fast. It can be used for polarization converter and divergent LC lens. In addition, a new method for simultaneously measuring the phase retardation and optic axis of a compensation film is demonstrated using an axially-symmetric sheared polymer network liquid crystal. By overlaying a tested compensation film with a calibrated SPNLC cell between crossed polarizers, the optic axis and phase retardation value of the compensation film can be determined. This simple technique can be used for simultaneously measuring the optic axis and phase retardations of both A- and C-plates. These compensation films have been used extensively in wide-view LCD industry. Therefore, this method will make an important impact to the LCD industry.

Wu, Yung-Hsun

12

Side-welded fast response sheathed thermocouple  

Energy Technology Data Exchange (ETDEWEB)

A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4-5 times faster and the thermal shock and cycling capabilities are substantially improved.

Carr, Kenneth R. (Knoxville, TN)

1981-01-01

13

Standing variation and new mutations both contribute to a fast response to selection for flowering time in maize inbreds  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In order to investigate the rate and limits of the response to selection from highly inbred genetic material and evaluate the respective contribution of standing variation and new mutations, we conducted a divergent selection experiment from maize inbred lines in open-field conditions during 7 years. Two maize commercial seed lots considered as inbred lines, F252 and MBS847, constituted two biological replicates of the experiment. In each replicate, we derived an Early and a Late population by selecting and selfing the earliest and the latest individuals, respectively, to produce the next generation. Results All populations, except the Early MBS847, responded to selection despite a short number of generations and a small effective population size. Part of the response can be attributed to standing genetic variation in the initial seed lot. Indeed, we identified one polymorphism initially segregating in the F252 seed lot at a candidate locus for flowering time, which explained 35% of the trait variation within the Late F252 population. However, the model that best explained our data takes into account both residual polymorphism in the initial seed lots and a constant input of heritable genetic variation by new (epi)mutations. Under this model, values of mutational heritability range from 0.013 to 0.025, and stand as an upper bound compare to what is reported in other species. Conclusions Our study reports a long-term divergent selection experiment for a complex trait, flowering time, conducted on maize in open-field conditions. Starting from a highly inbred material, we created within a few generations populations that strikingly differ from the initial seed lot for flowering time while preserving most of the phenotypic characteristics of the initial inbred. Such material is unique for studying the dynamics of the response to selection and its determinants. In addition to the fixation of a standing beneficial mutation associated with a large phenotypic effect, a constant input of genetic variance by new mutations has likely contributed to the response. We discuss our results in the context of the evolution and mutational dynamics of populations characterized by a small effective population size.

Durand Eléonore; Tenaillon Maud I; Ridel Céline; Coubriche Denis; Jamin Philippe; Jouanne Sophie; Ressayre Adrienne; Charcosset Alain; Dillmann Christine

2010-01-01

14

High photorefractive sensitivity and fast response time of near-stoichiometric and MgO doped LiNbO3:Fe crystals  

International Nuclear Information System (INIS)

Congruent LiNbO3:Fe and LiNbO3:Mg,Fe crystals were grown by Czochralski method, and vapor transport equilibration technique was employed to improve the [Li]/[Nb] ratios of these crystals. The influence of stoichiometry and MgO dopant on the photorefractive sensitivity and response time of LiNbO3:Fe crystals was investigated. Both stoichiometry and MgO dopant can effectively reduce the amount of intrinsic defects, but MgO can also decrease the concentration of Fe2+ ions in Li-sites. Near-stoichiometric and MgO doped LiNbO3:Fe crystal has high photorefractive sensitivity and fast response time. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2006-01-01

15

Response of fast plastic scintillator detector  

International Nuclear Information System (INIS)

Plastic scintillator detector is widely used now a days for the time of flight measurement of high velocity charged and non charged particle in many experiment of nuclear and high energy physics. The important parameters of a plastic scintillator are its luminescence response to various types of radiation, its time response characteristics (i.e., rise time, decay time, transit time of the light), and the attenuation of the light traveling through it. We are planning to build an array of detectors for TOF measurements of high energy reaction fragments. For this purpose, various types of ultra fast plastic scintillator with different types of readout have been tested using different types of sources and cosmic muons at our SINP Laboratory. Details of the testing results on the response of these detectors to electron (137Cs), gamma (60Co) and heavy charge particle like alpha (from 241Am) will be presented in the symposium

2012-01-01

16

Reducing preoperative fasting time: A trend based on evidence  

Directory of Open Access Journals (Sweden)

Full Text Available Preoperative fasting is mandatory before anesthesia to reduce the risk of aspiration. However, the prescribed 6-8 h of fasting is usually prolonged to 12-16 h for various reasons. Prolonged fasting triggers a metabolic response that precipitates gluconeogenesis and increases the organic response to trauma. Various randomized trials and meta-analyses have consistently shown that is safe to reduce the preoperative fasting time with a carbohydrate-rich drink up to 2 h before surgery. Benefits related to this shorter preoperative fasting include the reduction of postoperative gastrointestinal discomfort and insulin resistance. New formulas containing amino acids such as glutamine and other peptides are being studied and are promising candidates to be used to reduce preoperative fasting time.

José Eduardo de Aguilar-Nascimento; Diana Borges Dock-Nascimento

2010-01-01

17

Short-Time-Response measurements of nitrogen dioxide and peroxyacetyl nitrate by fast capillary gas chromatography with luminol detection.  

Energy Technology Data Exchange (ETDEWEB)

The interaction of hydrocarbons and nitrogen oxides in sunlight to produce photochemical smog has been well studied over the years. In the past, the workhorse for the measurement of NO{sub 2}and NO was the chemiluminescent reaction with ozone. This method has detection limits of approximately 0.5 ppb in most commercial instruments, but it cannot detect NO{sub 2} directly; the instrument detects NO and uses hot catalytic surfaces to decompose all other nitrogen oxides (including NO{sub 2}) to NO for detection (l). The main problem with the method is the inherent difficulty in detecting excited NO{sub 2}, which emits over a broad region beginning at approximately 660 nm and has a maximum at 1270 nm, thus requiring a red-shifted photomultiplier for detection. The use of luminol for direct chemiluminescent detection of NO{sub 2} was demonstrated to have greater inherent sensitivity (detection limits of 5 ppt) than the indirect ozone chemiluminescence detection (2). In the luminol system, a gas-liquid reaction leads to light emission with a maximum at approximately 425 nm, at the maximum sensitivity for most photomultiplier tubes. This emission is responsible for the increased detection sensitivities. The biggest problem with this method for direct measurement of NO{sub 2} has been interference due to other soluble oxidants, particularly peroxyacyl nitrates (PANs).

Marley, N. A.; Gaffney, J. S.; Drayton, P. J.

2000-12-07

18

Fast rise-time, fiber optic pin  

Energy Technology Data Exchange (ETDEWEB)

A reliable, simple fast-rise-time diagnostic has been developed for measuring the breakout time of the detonation wave in a detonating high explosive. The intrinsic rise time of the signals generated is less than one nanosecond. The technique, called FAT (Fiber Arrival Time), consists of an optical fiber with one end coated with ~1500 Å Aluminum. The coated end is placed in intimate contact with the surface of the explosive. The detonation wave interacting with the Al surface causes a prompt flash of light which is recorded at the output end of the fiber. The active area of the FAT probe end is 100 µm in diameter and centered to within ±10 µm also giving excellent spatial precision. When used in this mode, FAT overcomes difficulties of electronic and past fiber optic pins. When looking at a flyer plate arrival the time response appears to be a function of the metal plate velocity.

Roeske, F

1998-05-12

19

Fast-response protection from high currents  

International Nuclear Information System (INIS)

Protection devices for power electronic equipment from shorting current are described. The device is shunted using spark gaps with minimal possible number of spark gaps to protect it. High fast-response (

1989-01-01

20

A new scintillation counter with very fast resolving time (1961)  

International Nuclear Information System (INIS)

The rare gases used as scintillators are characterized by their short time of luminescence and by the linearity of their response as a function of the total energy imparted to the gas by the incident particle. It is possible with these scintillators, when associated with a fast response photomultiplier, to solve certain problems of nuclear physics demanding a linear detector with a very fast resolving time (a few nanoseconds). Two examples of the construction of this apparatus are described. The results obtained and future possibilities are briefly outlined. (author)

1961-01-01

 
 
 
 
21

Ultra-fast timing with plastic scintillators  

Energy Technology Data Exchange (ETDEWEB)

Fast timing detectors for time-of-flight measurements are essential identification tools for isotopes studied at fragment separators at major heavy-ion research facilities. While today's standard technique of utilizing a plastic scintillator read out by few photomultiplier tubes proofs to be efficient, it does not provide the required time resolution for future key experiments at, for example, the Super-FRS at FAIR. A common present-day approach is to use diamond detectors instead. While they do provide a better time resolution compared to scintillators, they are more difficult to use and far more expensive. Results from tests using a new design approach with standard materials will be presented. This leads to a much improved performance, but remains both cost-efficient, compact, and reliable. The design goals and how to accomplish them will be exemplified by the LYCCA (Lund-York-Cologne CAlorimeter) detector aiming for fast-beam experiments at HISPEC within NUSTAR.

Hoischen, Robert [Department of Physics, Lund University, S-22100 Lund (Sweden); Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Pietri, Stephane; Prokopowicz, Wawrzyniec; Schaffner, Henning; Gerl, Juergen; Wollersheim, Hans Juergen; Kurz, Nikolaus [Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, Dirk [Department of Physics, Lund University, S-22100 Lund (Sweden)

2009-07-01

22

Ultra-fast timing with plastic scintillators  

International Nuclear Information System (INIS)

[en] Fast timing detectors for time-of-flight measurements are essential identification tools for isotopes studied at fragment separators at major heavy-ion research facilities. While today's standard technique of utilizing a plastic scintillator read out by few photomultiplier tubes proofs to be efficient, it does not provide the required time resolution for future key experiments at, for example, the Super-FRS at FAIR. A common present-day approach is to use diamond detectors instead. While they do provide a better time resolution compared to scintillators, they are more difficult to use and far more expensive. Results from tests using a new design approach with standard materials will be presented. This leads to a much improved performance, but remains both cost-efficient, compact, and reliable. The design goals and how to accomplish them will be exemplified by the LYCCA (Lund-York-Cologne CAlorimeter) detector aiming for fast-beam experiments at HISPEC within NUSTAR.

2009-01-01

23

Time-resolved x-ray diffraction study of the piezoelectric crystal response to a fast change of an applied electric field  

Science.gov (United States)

Time-resolved measurements of the macroscopic and microscopic strains in piezoelectric crystals were performed with a novel data acquisition technique implemented on the basis of a field programmed gate array system. Both types of strains were induced in a crystal by an applied periodic high voltage with fast (within 100 ns) switches between opposite polarities and measured simultaneously by respective angular shifts and integrated intensities of synchrotron x-ray diffraction rocking curves. The time resolution achieved with the developed data acquisition system was 100 ns. The paper demonstrates the particular application of this technique for the investigations of time dynamics of lattice constants and atomic positions in a unit cell for piezoelectric BiB3O6 and Li2SO4.H2O crystals. It has been found that 100 ns fast rising time of an applied external electric field induces oscillations of the crystal lattice constants, visible as oscillations of Bragg peak angular positions. At the same time, these oscillations are not observed for the Bragg intensities, i.e., for fractional positions of atoms in the unit cell and correspondingly for bond lengths. The results allow suggesting a model for the mutual interconnection between the deformation of bond lengths and lattice constants in piezoelectric crystals.

Gorfman, Semen; Schmidt, Oleg; Ziolkowski, Michael; von Kozierowski, Marc; Pietsch, Ullrich

2010-09-01

24

Pembina spill response fast and effective  

International Nuclear Information System (INIS)

A break in a pipeline carrying light crude between Taylor and Prince George, British Columbia, occurred on Aug 1, 2000. The drop in pressure was first noted at the Federated Pipelines' control room in Calgary at 1.38 AM. The break was located within an hour. Within minutes of confirmation, the valves were closed upstream and downstream of the leak and spill response teams, equipment and Pembina officials were en route to the site, approximately 100 kms from the nearest town. By mid-afternoon of the same day three containment booms were in place and oil was already being pumped out of the river into a fleet of vacuum trucks. By Aug 4, the spill was fully contained and cleanup operations underway. At the peak of the containment operation about 40 pipeline employees and about 100 contractors and other responders were on the scene. An estimated one million litres of crude oil were released into the river; recovery operations were still in progress at press time. A post-incident review of the spill and containment efforts found that response was as fast and as well coordinated as could have been expected considering the night-time conditions. The B.C. Oil and Gas Commission considered the pipeline company's response excellent, and was also impressed by the cooperation among various pipeline companies and contractors. The break was eventually identified as a split in the lamination where two pipe edges join, a condition that cannot be detected in advance by present day technology. 1 map., 1 photo.

2000-01-01

25

Fast response bolometer for high temperature plasma  

International Nuclear Information System (INIS)

[en] A fast response bolometer is developed to measure the radiation loss from a high temperature plasma. Radiation from the plasma (mainly x-ray) is absorbed by a thin foil and heats it up. Change in far infrared (FIR) radiation, due to the change in temperature, emitted from the back surface of the foil is detected by an FIR detector which is contained in a shield box placed distant from a plasma generating machine to eliminate electrical noise. The FIR radiation is transmitted from the thin foil to the detector by a light pipe (metal pipe inner surface of which is polished). The foil (radiation absorber) consists of 5?m thick copper foil, both surfaces of which are coated with 1 ?m thick carbon to increase the sensitivity and to simplify the calibration procedure. Calibration is done by two methods: One is to obtain the relation between temperature of the foil and the output of the detector. The other is to measure the detector output when the foil is illuminated by a flashlight with known light energy. Latter calibration procedure is excellent in that it is reliable and can be carried out with the same arrangement as the radiation from the plasma is measured. The result of this calibration is 0.46mV/mJ. This figure can be increased by adoption of FIR light collecting system. Time response of the bolometer (conduction of heat from radiation absorbing surface to the back surface of the foil) is calculated to be 400 ns. The thickness of the foil is chosen in such a way that the radiation from the plasma with electron temperature of about 100 eV is almost completely absorbed. This bolometer is applicable to plasmas with higher temperature when the foil thickness is increased with the sacrifice of time response and sensitivity. (author)

1984-01-01

26

Fast response Full Bridge Power Factor Corrector  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A fast response Full Bridge Power Factor Corrector (FBPFC) is presented in this paper. The converter is combined by two interleaved boost cells and a conventional full bridge converter. As the interleaving technique is applied, the input ripple current of FBPFC are reduced. Experimental result shows...

Chan, CH; Pong, MH

27

Quartz Cherenkov Counters for Fast Timing: QUARTIC  

CERN Document Server

We have developed particle detectors based on fused silica (quartz) Cherenkov radiators read out with micro-channel plate photomultipliers (MCP-PMTs) or silicon photomultipliers (SiPMs) for high precision timing (Sigma(t) about 10-15 ps). One application is to measure the times of small angle protons from exclusive reactions, e.g. p + p - p + H + p, at the Large Hadron Collider, LHC. They may also be used to measure directional particle fluxes close to external or stored beams. The detectors have small areas (square cm), but need to be active very close (a few mm) to the intense LHC beam, and so must be radiation hard and nearly edgeless. We present results of tests of detectors with quartz bars inclined at the Cherenkov angle, and with bars in the form of an "L" (with a 90 degree corner). We also describe a possible design for a fast timing hodoscope with elements of a few square mm.

Albrow, M G; Los, S; Ramberg, E; Ronzhin, A; Samoylenko, V; Wenzel, H; Zatserklyaniy, A

2012-01-01

28

Quartz Cherenkov counters for fast timing: QUARTIC  

International Nuclear Information System (INIS)

[en] We have developed particle detectors based on fused silica (quartz) Cherenkov radiators read out with microchannel plate photomultipliers (MCP-PMTs) or silicon photomultipliers (SiPMs) for high precision timing (?t ? 10-15 ps). One application is to measure the times of small angle protons from exclusive reactions, p+p?p+X+p, at the Large Hadron Collider, LHC. They may also be used to measure directional particle fluxes close to external or stored beams. The detectors have small areas (cm2), but need to be active very close ( ? 4 mm) to the intense LHC beam, and so must be radiation hard and nearly edgeless. We present results of tests of detectors with quartz bars inclined at the Cherenkov angle, and with bars in the form of an 'L' (with a 90° corner). We also describe a possible design for a fast timing hodoscope with few mm2 elements.

2012-01-01

29

Long-time behaviour of fast breeders  

International Nuclear Information System (INIS)

For studying the long-time behaviour of fast breeders, a suitable O-dimensional model of fissile (plutonium), fertile (U238) and absorbing material (structural material and coolant) is investigated. Charging, discharging and re-charging of fissile and fertile material are idealized as continuous processes. Criticality requires continuous discharge of each specific Pu-composition . The time behaviour of the isotope composition is described by a first-order-differential- equation system whose solution was determined numerically for different initial conditions. Calculating the stationary isotope composition (stationary after a long time) leads to an eigenvalue problem with the plutonium current, to be discharged as eigenvalue and the Pu-isotope concentrations as eigenvector components. Generally, this eigenvalue problem has but one physically reasonable solution with the so-called Pu? as eigenvector. The eigenvalue determines the breeding rate. The principal structure of fuel recycling is investigated. (author)

1962-01-01

30

The Fast Tracker Real Time Processor  

CERN Document Server

As the LHC luminosity is ramped up to the SLHC Phase I level and beyond, the high rates, multiplicities, and energies of particles seen by the detectors will pose a unique challenge. Only a tiny fraction of the produced collisions can be stored on tape and immense real-time data reduction is needed. An effective trigger system must maintain high trigger efficiencies for the physics we are most interested in, and at the same time suppress the enormous QCD backgrounds. This requires massive computing power to minimize the online execution time of complex algorithms. A multi-level trigger is an effective solution for an otherwise impossible problem. The Fast Tracker (FTK)[1], is a proposed upgrade to the current ATLAS trigger system that will operate at full Level-1 output rates and provide high quality tracks reconstructed over the entire detector by the start of processing in Level-2. FTK solves the combinatorial challenge inherent to tracking by exploiting massive parallelism of associative memories [2] that ...

Annovi, A; The ATLAS collaboration

2011-01-01

31

Fast-response beam loss monitor  

International Nuclear Information System (INIS)

By connecting a polyethylene fiber to a photo-multiplier, a beam loss monitor with a fast response has been fabricated. The beam loss is measured by Cherenkov light generated by a charged particle penetrating a fiber. Although this monitor has the merits that the structure of the monitor is simple and cheap, it has the demerits that the signal has an energy dependence, and deterioration caused by radiation occurs. A plastic scintillating fiber and a quartz fiber have also been tested. The signal of the former fiber is strong and does not depend on the energy of the circulating beam. However, the deterioration is also very severe. On the contrary, the latter fiber has a long lifetime, though its signal is small. Some measurements are discussed here concerning various cases of extraction conditions. (author)

2001-01-01

32

Fast-response beam loss monitor  

Energy Technology Data Exchange (ETDEWEB)

By connecting a polyethylene fiber to a photo-multiplier, a beam loss monitor with a fast response has been fabricated. The beam loss is measured by Cherenkov light generated by a charged particle penetrating a fiber. Although this monitor has the merits that the structure of the monitor is simple and cheap, it has the demerits that the signal has an energy dependence, and deterioration caused by radiation occurs. A plastic scintillating fiber and a quartz fiber have also been tested. The signal of the former fiber is strong and does not depend on the energy of the circulating beam. However, the deterioration is also very severe. On the contrary, the latter fiber has a long lifetime, though its signal is small. Some measurements are discussed here concerning various cases of extraction conditions. (author)

Kawakubo, T.; Ishida, T.; Hiraishi, K.; Kadokura, E.; Yamaguchi, H. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

2001-03-01

33

Development of a small, nanosecond timing fast neutron spectrometer  

International Nuclear Information System (INIS)

A neutron spectrometer has been developed for use inside a fast neutron assembly. The spectrometer is small and insensitive to gamma radiation. An optical system was developed which could collect about 80 per cent of the light from an NE213 liquid scintillator and transmit it along a 450 mm quartz light guide to a high performance photomultiplier. To enable the detector to be used as a nanosecond timing spectrometer, several calibration measurements were made of the detector efficiency and response to monoenergetic neutrons

1980-01-01

34

Mutagenic response of peanut (arachis hypogaea L.) to fast neutrons  

International Nuclear Information System (INIS)

Dominant seeds of peanut were treated with varying doses of fast neutrons employing efficient pre- and post-irradiation techniques for determination of various plant responses useful in a long range program of mutation breeding. Mean reductions in seedling height and frequency of M1 somatic mutations increased with increasing radiation dose. No reduction in M1 seedset was obtained even in the dose above the LD50 of 1600 rads. The frequency of M2 macromutations ranged from only 3.60 - 5.65 per 100 M2 plants. The genetic basis of each of these radiation responses is briefly discussed. The high sensitivity of M1 peanut seedlings and growing plants to fast neutrons is probably due to the highly differentiated seed embryo at the time of irradiation while the radioresistance exhibited by the matured plant appears to be related to the polyploid genome of the species. (Auth.)

1984-01-01

35

Metabolic responses to exercise after fasting.  

UK PubMed Central (United Kingdom)

Fasting before exercise increases fat utilization and lowers the rate of muscle glycogen depletion. Since a 24-h fast also depletes liver glycogen, we were interested in blood glucose homeostasis during exercise after fasting. An experiment was conducted with human subjects to determine the effect of fasting on blood metabolite concentrations during exercise. Nine male subjects ran (70% maximum O2 consumption) two counterbalanced trials, once fed and once after a 23-h fast. Plasma glucose was elevated by exercise in the fasted trial but there was no difference between fed and fasted during exercise. Lactate was significantly higher (P less than 0.05) in fasted than fed throughout the exercise bout. Fat mobilization and utilization appeared to be greater in the fasted trial as evidenced by higher plasma concentrations of free fatty acids, glycerol, and beta-hydroxybutyrate as well as lower respiratory exchange ratio in the fasted trial during the first 30 min of exercise. These results demonstrate that in humans blood glucose concentration is maintained at normal levels during exercise after fasting despite the depletion of liver glycogen. Homeostasis is probably maintained as a result of increased gluconeogenesis and decreased utilization of glucose in the muscle as a result of lowered pyruvate dehydrogenase activity.

Dohm GL; Beeker RT; Israel RG; Tapscott EB

1986-10-01

36

A Stochastic Calculation of Fast Reactor Generation Times  

International Nuclear Information System (INIS)

Multigroup calculations for fast reactors are basically static in character, based on a representation of the system in which 25 or fewer groups are used to describe 5 or 6 decades in energy. While most of the uncertainty in calculations (as exemplified by generation times which are consistently 10 to 20% too low) is due to errors in cross sections, errors may also arise in averaging over broad groups; and in the treatment of elastic scattering by means of computed elastic removal cross-sections. Also, the multigroup method does not.permit convenient detailed study of the physics of slowing down in fast reactors. In this paper a new approach to calculation of fast reactor temporal and integral properties is described. With this method the neutron slowing down process is treated approximately as a discrete time, discrete state Markov process. Starting with an initial condition of a pulse of neutrons distributed with a fission spectrum, the neutron density as a function of energy and time over a large number ( >100) of energy 'sates' or 'groups' is evolved at discrete time steps. From this discrete representation of the time-energy dependent neutron density one is able to calculate a finely resolved discrete approximation to the distribution of slowing down times to first generation fission. The first time moment of this function is the generation time. Convolution of this distribution yields a function proportional to the time dependent response of a counter after a burst of fission spectrum neutrons. It is this function which is sampled in the Rossi-? experiment. Compared to the usual multigroup calculations the method has the advantage of not being directly dependent on spectral or adjoint calculations, and of being able to account for elastic scattering very accurately. Further, it is a dynamic calculation which follows the evolution of the neutron slowing down process in detail, as opposed to the usual calculations based on static fluxes. The method is versatile and may be applied to fast spectral and criticality calculations, and the usual spectral indicators such as central core fission ratios. Example calculations using the discrete state Markov method have been performed in systems with simple geometry. These calculational results are compared to those of other methods. (author)

1967-11-03

37

The relationship between shock response spectrum and fast Fourier transform  

International Nuclear Information System (INIS)

In this paper the basic relationship between response spectrum and fast Fourier transform is laid down. Since a long time the response spectrum has been used by structural engineers in the seismic domain and nowadays it is going to be used to define transient motions. This way to define the excitation is more general and more real than the use of classical shape pulses for the reproduction of real environment. Nevertheless the response spectrum of a real excitation represents a loss of some information with respect to the Fourier transform. A useful discussion could arise from these observations. Appendix A gives the relationship between the mathematic Fourier transform and the digital Fourier transform given by computers, while Appendix B gives some examples of response spectra and Fourier transforms of simple functions. (author)

2001-01-01

38

Wave-induced hydroelastic response of fast monohull displacement ships  

DEFF Research Database (Denmark)

High-speed ships are weight sensitive structures and high strength steel, aluminium or composites are preferred building materials. It is characteristic for these materials that they result in larger hull flexibility than more conventional materials. Therefore, for large fast ships the lowest natural frequencies of the global hull modes can be relatively low compared to the frequency of wave encounter.In the present paper the effect of hull flexibility on the wave-induced springing and whipping vibrations is investigated in stationary stochastic seaways. The calculations are performed using a quadratic strip theory formulated in the frequency domain and a fully non-linear time-domain strip theory. The hydroelastic response is thereby excited partly by resonance and partly by non-linear excitation. The calculations are carried out for a recent proposal for a fast monohull containership.

Jensen, JØrgen Juncher; Wang, Zhaohui

1998-01-01

39

Response times to conceptual questions  

Science.gov (United States)

We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.

Lasry, Nathaniel; Watkins, Jessica; Mazur, Eric; Ibrahim, Ahmed

2013-09-01

40

On DSS Method for a Fast Identification of the Static and Dynamic Responses of Servovalves  

CERN Document Server

In this work we consider a class of quasilinear systems of differential equations which allows to describe dynamics of electrohydraulic servovalves. A method for fast identification of static and dynamic responses, by a short-time experiment, is described.

Dietz, J O; Shashkov, M V

2002-01-01

 
 
 
 
41

Fast-timing methods for semiconductor detectors  

Energy Technology Data Exchange (ETDEWEB)

The basic parameters are discussed which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter.

Spieler, H.

1982-03-01

42

Fast timing methods for semiconductor detectors. Revision  

Energy Technology Data Exchange (ETDEWEB)

This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter.

Spieler, H.

1984-10-01

43

Fast Passive Summators for Timing Applications  

CERN Multimedia

Our basic present choice for the candidates to the multiplicity counters of ALICE is the Micro Channel Plate based detector (FMD-MCP) [1,2]. The signals from MCP detector are very sharp in time. The signal from a single particle has a leading edge rise time of about 200ps and a width of 1ns.

Kolojvari, A A; CERN. Geneva; Tsimbal, F A; Tulina, T A; Valiev, F F; Vinogradov, L I; Potapov, S V; Novikov, I A

1995-01-01

44

Response time of internauts  

CERN Document Server

A new experiment measuring the dynamical response of the Internet population to a ``point-like'' perturbation has been performed. The nature of the perturbation was that of an announcement, specifically a web-interview on stock market crashes, which contained the URL to the author's articles on the subject. It was established that the download rate obeys the relation ~ 1/t in qualitative agreement with previously reported results.

Johansen, A

2001-01-01

45

New charge sensitive preamplifier with a fast timing signal output  

International Nuclear Information System (INIS)

[en] A charge sensitive preamplifier with a fast timing output has been developed. Different from the Sherman's method which uses a low gain fast amplifier and a high gain slow amplifier in parallel as the second stage, the timing output of this preamplifier is extracted from the fast current signal in the collector current of the cascode type amplifier by using a current-voltage convertor. This preamplifier has a good resolution when used with a thin silicon detector which has a large capacitance. (auth.)

1977-01-01

46

Rugged calorimeter with a fast rise time  

Energy Technology Data Exchange (ETDEWEB)

An intrinsic 1-mil-thick gold foil calorimeter has been developed which rises to 95% of the energy deposited in less than 2 microseconds. This calorimeter is very rugged, and can withstand rough handling without damage. The time constant is long, in the millisecond range, because of its unique construction. Use of this calorimeter has produced 100% data recovery, and agreement with true deposition to less than 10%.

McMurtry, W.M.; Dolce, S.R.

1980-01-01

47

Directional fast neutron detection using a time projection chamber  

International Nuclear Information System (INIS)

[en] Measurement of the three dimensional trajectory and specific ionization of recoil protons using a hydrogen gas time projection chamber provides directional information about incident fast neutrons. Here we demonstrate directional fast neutron detection using such a device. The wide field of view and excellent gamma rejection that are obtained suggest that this device is well suited to searches for special nuclear materials, among other applications.

2010-12-01

48

Uncertainty evaluation of fast reactor core seismic response  

International Nuclear Information System (INIS)

Response Surface Methodology (RSM) has been applied to the evaluation of the uncertainties on the seismic behaviour of a fast reactor core. For this study preliminary data concerning the Italian PEC reactor test facility have been used. The structural dynamic analysis has been performed by means of the SAP IV code for the whole reactor block and CORALIE for the core. Once a certain acceleration time history at the ground has been assumed, the characteristics of the acceleration time-history at the core support grid, related to the vessel-core dynamic interaction, the reactor vessel stiffness, the frequency response, damping and impact coefficients of the core elements, and the number of core element rows assumed in the non-linear core calculations have been identified as the major contributors to the overall uncertainty. For each element type the responses calculated with CORALIE have been approximated by means of polynomial functions, whose adequacy in the variable space investigated has been tested by means of a further set of dynamic calculations. Finally the input uncertainties have been propagated by a Monte Carlo routine (MUP) under different assumptions to assess the sensitivity of the output distribution with respect to the kind of input probability distributions. The aim of this latter analysis step is the proposal of an adequate approach for verifying that the control rods succeed at a high probability to fall inside their guide-tubes in the case of an earth-quake, so that the reactor can be safely shut-down. The paper describes the details of the study and demonstrates RSM adequacy for the analysis of the input uncertainty effects on the core seismic response. It also shows that the core element frequencies and damping coefficients, as well as the vessel-core dynamic interaction parameters, are the main variables affecting such response, which therefore need a sufficiently precise definition. (orig.).

1983-01-01

49

Accuracy of single photoelectron time spread measurement of fast photomultipliers  

International Nuclear Information System (INIS)

[en] The accuracy of time spread measurements of fast photomultipliers was investigated, using single photoelectrons. The effect of the finite light pulse width on the measurement accuracy was determined and discussed. Experimental data were obtained on a special measuring system for light pulse widths ranging from 200 psec to 10 nsec, using fast photomultipliers 8850 and C31024 with optimized operating conditions for minimum transit time spread. A modified exponential function expression and curve-fitting parameters are given, which fit closely the experimentally obtained data over a wide dynamic range of light pulse widths. (U.S.)

1975-05-26

50

Investigating Two Different Training Time Frames during Ramadan Fasting.  

UK PubMed Central (United Kingdom)

PURPOSE: Muslim athletes may continue training and competing while they are fasting. There is a concern about negative effects of fasting on sports performance. This study aimed to investigate the influence of two training time frames on athletes' body composition and performance during Ramadan fasting. METHODS: An observational study was conducted and thirty four male volunteer athletes from different sports including volleyball, karate, taekwondo and football were assigned in two groups. The first group included 14 elite athletes who during Ramadan voluntarily participated in training sessions at 1 hour before Iftar (BI) and the second group of 20 elite athletes who during Ramadan participated in training sessions at 3 hours after Iftar (AI). Testing was performed one week before; in the first and fourth weeks of Ramadan and one week after Ramadan. Weights, heights and skinfold thickness were assessed at each time point and body mass index was calculated. Each player was assessed for agility and explosive strength as well. RESULTS: The mean weight and body mass index of both groups decreased significantly during Ramadan (P<0.001). Performance variables were not negatively affected by fasting in BI or AI group athletes. CONCLUSIONS: Weight reduction might come with either BI or AI training schedules in Ramadan. Daytime or evening training did not inversely affect the agility and power performances in a group of elite athletes during Ramadan fasting.

Kordi R; Abdollahi M; Memari AH; Najafabadi MG

2011-09-01

51

Fast Arnold Diffusion in three time scale systems  

CERN Document Server

We consider the problem of Arnold Diffusion for nearly integrable partially isochronous Hamiltonian systems with three time scales. By means of a careful shadowing analysis, based on a variational technique, we prove that, along special directions, Arnold diffusion takes place with fast (polynomial) speed, even though the ``splitting determinant'' is exponentially small.

Berti, M; Berti, Massimiliano; Bolle, Philippe

2001-01-01

52

Fast timing study of a CeBr3 crystal: Time resolution below 120 ps at 60Co energies  

Science.gov (United States)

We report on the time response of a novel inorganic scintillator, CeBr3. The measurements were performed using a cylindrical crystal of 1-in. in height and 1-in. in diameter at 22Na and 60Co photon energies. The time response was measured against a fast reference BaF2 detector. Hamamatsu R9779 and Photonis XP20D0 fast photomultipliers (PMTs) were used. The PMT bias voltages and Constant Fraction Discriminator settings were optimized with respect to the timing resolution. The Full Width at Half Maximum (FWHM) time resolution for an individual CeBr3 crystal coupled to Hamamatsu PMT is found here to be as low as 119 ps at 60Co energies, which is comparable to the resolution of 107 ps reported for LaBr3(Ce). For 511 keV photons the measured FWHM time resolution for CeBr3 coupled to the Hamamatsu PMT is 164 ps.

Fraile, L. M.; Mach, H.; Vedia, V.; Olaizola, B.; Paziy, V.; Picado, E.; Udías, J. M.

2013-02-01

53

Real time face recognition using adaboost improved fast PCA algorithm  

CERN Document Server

This paper presents an automated system for human face recognition in a real time background world for a large homemade dataset of persons face. The task is very difficult as the real time background subtraction in an image is still a challenge. Addition to this there is a huge variation in human face image in terms of size, pose and expression. The system proposed collapses most of this variance. To detect real time human face AdaBoost with Haar cascade is used and a simple fast PCA and LDA is used to recognize the faces detected. The matched face is then used to mark attendance in the laboratory, in our case. This biometric system is a real time attendance system based on the human face recognition with a simple and fast algorithms and gaining a high accuracy rate..

Kumar, K Susheel; Tripathi, R C

2011-01-01

54

Fast time-resolved aerosol collector: proof of concept  

Directory of Open Access Journals (Sweden)

Full Text Available Atmospheric particles can be collected in the field on substrates for subsequent laboratory analysis via chemically sensitive single particle methods such as scanning electron microscopy with energy dispersive x-ray analysis. With moving substrates time resolution of seconds to minutes can be achieved. In this paper, we demonstrate how to increase the time resolution when collecting particles on a substrate to a few milliseconds to provide real-time information. Our fast time-resolved aerosol collector ("Fast-TRAC") microscopically observes the particle collection on a substrate and records an on-line video. Particle arrivals are resolved to within a single frame (4–17 ms in this setup), and the spatial locations are matched to the subsequent single particle analysis. This approach also provides in-situ information on particle size and number concentration. Applications are expected in airborne studies of cloud microstructure, pollution plumes, and surface long-term monitoring.

X.-Y. Yu; J. P. Cowin; M. J. Iedema; H. Ali

2010-01-01

55

Fast time-evolution method for dynamical systems  

UK PubMed Central (United Kingdom)

A fast time-evolution method is developed for systems for which the dynamical behavior can be reduced to the eigenvector/eigenvalue problem. The method does not use the eigenvectors/eigenvalues themselves and is based on a polynominal expansion of the formal operator solution in the eigenfrequency domain. It is complementary to the standard time-integration approaches and allows one to calculate or simulate the state of a system at arbitrary times. The time evolution of, e.g., classical harmonic atomic systems and quantum systems described by linear Hamiltonians can be treated by this method.

Loh YL; Taraskin SN; Elliott SR

2000-03-01

56

Fast time-evolution method for dynamical systems  

Science.gov (United States)

A fast time-evolution method is developed for systems for which the dynamical behavior can be reduced to the eigenvector/eigenvalue problem. The method does not use the eigenvectors/eigenvalues themselves and is based on a polynominal expansion of the formal operator solution in the eigenfrequency domain. It is complementary to the standard time-integration approaches and allows one to calculate or simulate the state of a system at arbitrary times. The time evolution of, e.g., classical harmonic atomic systems and quantum systems described by linear Hamiltonians can be treated by this method. PMID:11018867

Loh; Taraskin; Elliott

2000-03-13

57

REAL TIME FACE RECOGNITION USING ADABOOST IMPROVED FAST PCA ALGORITHM  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents an automated system for human face recognition in a real time background world fora large homemade dataset of persons face. The task is very difficult as the real time backgroundsubtraction in an image is still a challenge. Addition to this there is a huge variation in human face imagein terms of size, pose and expression. The system proposed collapses most of this variance. To detect realtime human face AdaBoost with Haar cascade is used and a simple fast PCA and LDA is used torecognize the faces detected. The matched face is then used to mark attendance in the laboratory, in ourcase. This biometric system is a real time attendance system based on the human face recognition with asimple and fast algorithms and gaining a high accuracy rate..

K. Susheel Kumar; Shitala Prasad; Vijay Bhaskar Semwal; R C Tripathi

2011-01-01

58

Experimental evaluation of fast-response of eddy valves  

Energy Technology Data Exchange (ETDEWEB)

Calculated parameters of the main element, the eddy valve are examined. The model characteristics were studied on a special unit, and with the involvement of similarity methods, an evaluation was made of the fast response of a full-scale element.

Tobayakov, V.O.

1982-01-01

59

Portion sizes and obesity: responses of fast-food companies.  

Science.gov (United States)

Because the sizes of food portions, especially of fast food, have increased in parallel with rising rates of overweight, health authorities have called on fast-food chains to decrease the sizes of menu items. From 2002 to 2006, we examined responses of fast-food chains to such calls by determining the current sizes of sodas, French fries, and hamburgers at three leading chains and comparing them to sizes observed in 1998 and 2002. Although McDonald's recently phased out its largest offerings, current items are similar to 1998 sizes and greatly exceed those offered when the company opened in 1955. Burger King and Wendy's have increased portion sizes, even while health authorities are calling for portion size reductions. Fast-food portions in the United States are larger than in Europe. These observations suggest that voluntary efforts by fast-food companies to reduce portion sizes are unlikely to be effective, and that policy approaches are needed to reduce energy intake from fast food. PMID:17585324

Young, Lisa R; Nestle, Marion

2007-07-01

60

Fast exponential fitting algorithm for real-time instrumental use  

International Nuclear Information System (INIS)

We report on a very fast fitting algorithm for single exponential functions which is based on the method of successive integration. The algorithm corrects the systematic error of trapezoidal integration. The new algorithm needs only 150 ?s for a dataset of 1536 points and is around 700 times faster than the nonlinear Levenberg-Marquardt fit provided by LABVIEW. This makes it suitable for real-time instrumental use. Beside the better time resolution, the acceleration allows more averaging, which leads to higher precision. In our experiment instrumental sensitivity was improved by a factor of 3.7

2004-01-01

 
 
 
 
61

A Space/Fast-Time Adaptive Monopulse Technique  

Directory of Open Access Journals (Sweden)

Full Text Available Mainbeam jamming poses a particularly difficult challenge for conventional monopulse radars. In such cases spatially adaptive processing provides some interference suppression when the target and jammer are not exactly coaligned. However, as the target angle approaches that of the jammer, mitigation performance is increasingly hampered and distortions are introduced into the resulting beam pattern. Both of these factors limit the reliability of a spatially adaptive monopulse processor. The presence of coherent multipath in the form of terrain-scattered interference (TSI), although normally considered a nuisance, can be exploited to suppress mainbeam jamming with space/fast-time processing. A method is presented offering space/fast-time monopulse processing with distortionless spatial array patterns that can achieve improved angle estimation over spatially adaptive monopulse. Performance results for the monopulse processor are obtained for mountaintop data containing a jammer and TSI, which demonstrate a dramatic improvement in performance over conventional monopulse and spatially adaptive monopulse.

Seliktar Yaron; Williams Douglas B; Holder E Jeff

2006-01-01

62

Directional Detection of Fast Neutrons Using a Time Projection Chamber  

Energy Technology Data Exchange (ETDEWEB)

Spontaneous fission in Special Nuclear Material (SNM) such as plutonium and highly enriched uranium (HEU) results in the emission of neutrons with energies in the MeV range (hereafter 'fast neutrons'). These fast neutrons are largely unaffected by the few centimeters of intervening high-Z material that would suffice for attenuating most emitted gamma rays, while tens of centimeters of hydrogenous materials are required to achieve substantial attenuation of neutron fluxes from SNM. Neutron detectors are therefore an important complement to gamma-ray detectors in SNM search and monitoring applications. The rate at which SNM emits fast neutrons varies from about 2 per kilogram per second for typical HEU to some 60,000 per kilogram per second for metallic weapons grade plutonium. These rates can be compared with typical sea-level (cosmogenic) neutron backgrounds of roughly 5 per second per square meter per steradian in the relevant energy range [1]. The fact that the backgrounds are largely isotropic makes directional neutron detection especially attractive for SNM detection. The ability to detect, localize, and ultimately identify fast neutron sources at standoff will ultimately be limited by this background rate. Fast neutrons are particularly well suited to standoff detection and localization of SNM or other fast neutrons sources. Fast neutrons have attenuation lengths of about 60 meters in air, and retain considerable information about their source direction even after one or two scatters. Knowledge of the incoming direction of a fast neutron, from SNM or otherwise, has the potential to significantly improve signal to background in a variety of applications, since the background arriving from any one direction is a small fraction of the total background. Imaging or directional information therefore allows for source detection at a larger standoff distance or with shorter dwell times compared to nondirectional detectors, provided high detection efficiency can be maintained. Directional detection of neutrons has been previously considered for applications such as controlled fusion neutron imaging [2], nuclear fuel safety research [3], imaging of solar neutrons and SNM [4], and in nuclear science [5]. The use of scintillating crystals and fibers has been proposed for directional neutron detection [6]. Recently, a neutron scatter camera has been designed, constructed, and tested for imaging of fast neutrons, characteristic for SNM material fission [7]. The neutron scatter camera relies on the measurement of the proton recoil angle and proton energy by time of flight between two segmented solid-state detectors. A single-measurement result from the neutron scatter camera is a ring containing the possible incident neutron direction. Here we describe the development and commissioning of a directional neutron detection system based on a time projection chamber (TPC) detector. The TPC, which has been widely used in particle and nuclear physics research for several decades, provides a convenient means of measuring the full 3D trajectory, specific ionization (i.e particle type) and energy of charged particles. For this application, we observe recoil protons produced by fast neutron scatters on protons in hydrogen or methane gas. Gas pressures of a few ATM provide reasonable neutron interaction/scattering rates.

Bowden, N; Heffner, M; Carosi, G; Carter, D; Foxe, M; Jovanovic, I

2009-06-03

63

Fast response of InSb Schottky detector.  

Science.gov (United States)

An InSb Schottky detector, fabricated from an undoped InSb wafer with Hall mobility which is higher than those of previously employed InSb wafers, was used for alpha particle detection. The output pulse of this InSb detector showed a very fast rise time, which was comparable with the output pulses of scintillation detectors. PMID:17552865

Kanno, Ikuo; Hishiki, Shigeomi; Kogetsu, Yoshitaka; Nakamura, Tatsuya; Katagiri, Masaki

2007-05-01

64

Fast response of InSb Schottky detector.  

UK PubMed Central (United Kingdom)

An InSb Schottky detector, fabricated from an undoped InSb wafer with Hall mobility which is higher than those of previously employed InSb wafers, was used for alpha particle detection. The output pulse of this InSb detector showed a very fast rise time, which was comparable with the output pulses of scintillation detectors.

Kanno I; Hishiki S; Kogetsu Y; Nakamura T; Katagiri M

2007-05-01

65

Response times in healthcare systems.  

UK PubMed Central (United Kingdom)

It is a goal universally acknowledged that a healthcare system should treat its patients (and especially those in need of critical care) in a timely manner. However, this is often not achieved in practice, particularly in state-run public healthcare systems that suffer from high patient demand and limited resources. In particular, Accident and Emergency (A&E) departments in England have been placed under increasing pressure, with attendances rising year on year, and a national government target whereby 98% of patients should spend 4 hours or less in an A&E department from arrival to admission, transfer or discharge. This thesis presents techniques and tools to characterise and forecast patient arrivals, to model patient flow and to assess the response-time impact of different resource allocations, patient treatment schemes and workload scenarios. Having obtained ethical approval to access five years of pseudonymised patient timing data from a large case study A&E department, we present a number of time series models that characterise and forecast daily A&E patient arrivals. Patient arrivals are classified as one of two arrival streams (walk-in and ambulance) by mode of arrival. Using power spectrum analysis, we find the two arrival streams exhibit different statistical properties and hence require separate time series models. We find that structural time series models best characterise and forecast walk-in arrivals, but that time series analysis may not be appropriate for ambulance arrivals; this prompts us to investigate characterisation by a non-homogeneous Poisson process. Next we present a hierarchical multiclass queueing network model of patient flow in our case study A&E department. We investigate via a discrete-event simulation the impact of class and time-based priority treatment of patients, and compare the resulting service-time densities and moments with actual data. Then, by performing bottleneck analysis and investigating various workload and resource scenarios, we pinpoint the resources that have the greatest impact on mean service times. Finally we describe an approximate generating function analysis technique which efficiently approximates the first two moments of customer response time in class-dependent priority queueing networks with population constraints. This technique is applied to the model of A&E and the results compared with those from simulation. We find good agreement for mean service times especially when minors patients are given priority.

Au-Yeung SWM

66

A Fast Response Gas Tension Device for Use on Profiling Floats  

Science.gov (United States)

We present the development and testing phase of a new fast-response gas tension device (GTD) designed specifically for use on an air-deployable, buoyancy adjustable, profiling float. The GTD measures total dissolved air pressure when equilibrated with the local waters through a gas permeable membrane. Dissolved N2 levels are calculated using gas tension, water temperature, salinity and dissolved O2. The new fast-response GTD maintains the existing GTD's high precision and accuracy (0.01 %) but provides a significantly faster response. The new design physically separates the existing GTD into two primary components, a membrane interface and a precision pressure sensor. The two components communicate remotely through a low dead-volume tube. This allows the existing GTD to be minaturized for incorporation on the float and allows use of a novel, water pumped, larger surface area, fast response membrane interface. The equilibration time of the new instrument varies with depth due to compression of the membrane and its associated reduction in gas pernmeability. This effect is found to be significant to a depth of 10-20 m. In addition, the large surface area of the new fast-response interface provides a significant hydro-static response to the GTD due to degassing of the air dissolved in the membrane when it compresses. These responses are however very repeatable allowing the raw GTD signal to be corrected. The new GTD design equilibrates fastest near the sea surface and has a minimum response time (e-folding) of around 2 minutes. We suspect this can be improved further. The response time at 50 m is around 10 minutes. The depth controllable float enables an optimal 'sample-and-hold' approach at specified depths to ensure complete equilibration of the GTD. This GTD-float package allows remote upper ocean dissolved O2/N2 profiles, and time series at specified depths, to be collected for use in air-sea gas exchange and net biological productivity studies.

McNeil, C. L.; D'Asaro, E. A.; Johnson, B. D.

2004-12-01

67

Automatic Synthesis of Fast Compact Self-Timed Control Circuits  

UK PubMed Central (United Kingdom)

We present a tool called MEAT which has been designed to automatically synthesize transistorlevel, CMOS, self-timed control circuits. MEAT has been used to specify and synthesize self-timedcircuits for a fully self-timed 300,000 transistor communication coprocessor. The design is specified usingfinite state machines which permit btrst-mod inputs. Burst-mode is a limited form of MIC (multipleinput change) signalling. The primary goal of MEAT is to produce fast and compact circuits. In order toachieve this goal, MEAT implementations permit timing assumptions which can be verifiably supportedat the physical implementation level, and result in significant improvements in speed and area of thedesign. Since MEAT has been used for large designs, we have also been forced to make the algorithmsefficient. The result is a tool which is efficient, easy to use by today's hardware designers since thespecification is based on the commonly used finite state machine control model, and synthesizes CMOStransistor implementations that are self-timed, fast and compact. The paper presents a description ofthe tool, the nature of the algorithms used, and examples of its use.

Bill Coates; A Davis; Kenneth S. Stevens

68

On Fast-Decodable Space-Time Block Codes  

CERN Multimedia

We focus on full-rate, fast-decodable space-time block codes (STBCs) for 2x2 and 4x2 multiple-input multiple-output (MIMO) transmission. We first derive conditions for reduced-complexity maximum-likelihood decoding, and apply them to a unified analysis of two families of 2x2 STBCs that were recently proposed. In particular, we describe a reduced-complexity sphere decoding algorithm suitable for QAM signal constellations. Next, we derive a novel reduced-complexity 4x2 STBC, and show that it outperforms all previously known codes with certain constellations.

Biglieri, Ezio; Viterbo, Emanuele

2007-01-01

69

Modeling and Analysis of the Role of Fast-Response Energy Storage in the Smart Grid  

CERN Multimedia

The large short time-scale variability of renewable energy resources presents significant challenges to the reliable operation of power systems. This variability can be mitigated by deploying fast-ramping generators. However, these generators are costly to operate and produce environmentally harmful emissions. Fast-response energy storage devices, such as batteries and flywheels, provide an environmentally friendly alternative, but are expensive and have limited capacity. To study the environmental benefits of storage, we introduce a slotted-time dynamic residual dc power flow model with the prediction error of the difference between the generation (including renewables) and the load as input and the fast-ramping generation and the storage (charging/discharging) operation as the control variables used to ensure that the demand is satisfied (as much as possible) in each time slot. We assume the input prediction error sequence to be i.i.d. zero-mean random variables. The optimal power flow problem is then formu...

Su, Han-I

2011-01-01

70

Fast time variations of supernova neutrino fluxes and their detectability  

CERN Multimedia

In the delayed explosion scenario of core-collapse supernovae (SNe), the accretion phase shows pronounced convective overturns and a low-multipole hydrodynamic instability, the standing accretion shock instability (SASI). These effects imprint detectable fast time variations on the emerging neutrino flux. Among existing detectors, IceCube is best suited to this task, providing an event rate of ~1000 events per ms during the accretion phase for a fiducial SN distance of 10 kpc, comparable to what could be achieved with a megaton water Cherenkov detector. If the SASI activity lasts for several hundred ms, a Fourier component with an amplitude of 1% of the average signal clearly sticks out from the shot noise. We analyze in detail the output of axially symmetric hydrodynamical simulations that predict much larger amplitudes up to frequencies of a few hundred Hz. If these models are roughly representative for realistic SNe, fast time variations of the neutrino signal are easily detectable in IceCube or future meg...

Lund, Tina; Lunardini, Cecilia; Janka, Hans-Thomas; Raffelt, Georg

2010-01-01

71

Interorgan coordination of the murine adaptive response to fasting.  

UK PubMed Central (United Kingdom)

Starvation elicits a complex adaptive response in an organism. No information on transcriptional regulation of metabolic adaptations is available. We, therefore, studied the gene expression profiles of brain, small intestine, kidney, liver, and skeletal muscle in mice that were subjected to 0-72 h of fasting. Functional-category enrichment, text mining, and network analyses were employed to scrutinize the overall adaptation, aiming to identify responsive pathways, processes, and networks, and their regulation. The observed transcriptomics response did not follow the accepted "carbohydrate-lipid-protein" succession of expenditure of energy substrates. Instead, these processes were activated simultaneously in different organs during the entire period. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, and by increased proteolysis in the muscle. The brain was extremely well protected from the sequels of starvation. 60% of the identified overconnected transcription factors were organ-specific, 6% were common for 4 organs, with nuclear receptors as protagonists, accounting for almost 40% of all transcriptional regulators during fasting. The common transcription factors were PPAR?, HNF4?, GCR?, AR (androgen receptor), SREBP1 and -2, FOXOs, EGR1, c-JUN, c-MYC, SP1, YY1, and ETS1. Our data strongly suggest that the control of metabolism in four metabolically active organs is exerted by transcription factors that are activated by nutrient signals and serves, at least partly, to prevent irreversible brain damage.

Hakvoort TB; Moerland PD; Frijters R; Sokolovi? A; Labruyère WT; Vermeulen JL; Ver Loren van Themaat E; Breit TM; Wittink FR; van Kampen AH; Verhoeven AJ; Lamers WH; Sokolovi? M

2011-05-01

72

Interorgan Coordination of the Murine Adaptive Response to Fasting*  

Science.gov (United States)

Starvation elicits a complex adaptive response in an organism. No information on transcriptional regulation of metabolic adaptations is available. We, therefore, studied the gene expression profiles of brain, small intestine, kidney, liver, and skeletal muscle in mice that were subjected to 0–72 h of fasting. Functional-category enrichment, text mining, and network analyses were employed to scrutinize the overall adaptation, aiming to identify responsive pathways, processes, and networks, and their regulation. The observed transcriptomics response did not follow the accepted “carbohydrate-lipid-protein” succession of expenditure of energy substrates. Instead, these processes were activated simultaneously in different organs during the entire period. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, and by increased proteolysis in the muscle. The brain was extremely well protected from the sequels of starvation. 60% of the identified overconnected transcription factors were organ-specific, 6% were common for 4 organs, with nuclear receptors as protagonists, accounting for almost 40% of all transcriptional regulators during fasting. The common transcription factors were PPAR?, HNF4?, GCR?, AR (androgen receptor), SREBP1 and -2, FOXOs, EGR1, c-JUN, c-MYC, SP1, YY1, and ETS1. Our data strongly suggest that the control of metabolism in four metabolically active organs is exerted by transcription factors that are activated by nutrient signals and serves, at least partly, to prevent irreversible brain damage.

Hakvoort, Theodorus B. M.; Moerland, Perry D.; Frijters, Raoul; Sokolovic, Aleksandar; Labruyere, Wilhelmina T.; Vermeulen, Jacqueline L. M.; Ver Loren van Themaat, Emiel; Breit, Timo M.; Wittink, Floyd R. A.; van Kampen, Antoine H. C.; Verhoeven, Arthur J.; Lamers, Wouter H.; Sokolovic, Milka

2011-01-01

73

Response time and decision making: An experimental study  

Directory of Open Access Journals (Sweden)

Full Text Available Response time is used here to interpret choice in decision problems. I first establish that there is a close connection between short response time and choices that are clearly a mistake. I then investigate whether a correlation also exists between response time and behavior that is inconsistent with some standard theories of decision making. The lack of such a correlation could be interpreted to imply that such behavior does not reflect a mistake. It is also shown that a typology of slow and fast responders may, in some cases, be more useful than the standard typologies.

Ariel Rubenstein

2013-01-01

74

Fast response and recovery of hydrogen sensing in Pd-Pt nanoparticle-graphene composite layers  

Energy Technology Data Exchange (ETDEWEB)

This study reports the fast response and recovery of hydrogen sensing in nanoparticle-graphene composite layers fabricated using chemical methods and comprising of isolated Pd alloy nanoparticles dispersed onto graphene layers. For 2% hydrogen at 40 {sup 0}C and 1 atm pressure, a response time of < 2 s and a recovery time of 18 s are observed. The fast response and recovery observed during sensing are due to hydrogen-induced changes in the work function of the Pd alloy and modification in the distribution of defect states in the graphene band gap due to gas adsorption. The results of hydrogen sensing in the new class of Pd-Pt nanoparticle-graphene composite material are important for understanding the effect of gas adsorption on electronic conduction in graphene layers and for developing a new type of gas sensor based on changes in the electronic properties of the interface.

Kumar, Rakesh; Varandani, Deepak; Mehta, B R; Singh, V N [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Wen Zhenhai; Feng Xinliang; Muellen, Klaus, E-mail: brmehta@physics.iitd.ernet.in [Max-Planck Institute for Polymer Research, D-55128 Mainz (Germany)

2011-07-08

75

Fast and Slow Transient Response of WECS with Simultaneous Actions  

Directory of Open Access Journals (Sweden)

Full Text Available This paper details the transient operation of a wind energy conversion system (WECS) used simultaneously as an ac- tive filter and power generator. This study is intended to address the system response to two types of transient phenomena: voltage dips (fast transients) and wind speed variations (slow transients). The system response to voltage dips is governed by the electrical system dynamics and control method and results in the evaluation of the WECS low-voltage ride through capability. The study of the system response to wind speed variations requires a complete me- chanical model to be included. Simulation results are presented for a typical WECS, and a discussion is carried out dealing with the generalization of the present work to other configurations.

M.Amarendra; S.Srikanth; G. Siva Suteja; B.Prasanna Lakshmi; K.Madhavi Latha

2012-01-01

76

Wave-induced Hydroelastic response of fast monohull ships  

DEFF Research Database (Denmark)

High-speed ships are weight sensitive structures and high strength steel, aluminium or composites are preferred building materials. it is characteristic for these materials that they result in larger hull flexibility than more conventional materials. Therefore, for large fast ships the lowest natural frequencies of the global hull modes can be relatively low compared to the frequency of wave encounter. In the present paper the effect of hull flexibility on the wave-induced springing vibrations is investigated in stationary stochastic seaways. The calculations are performed within the framework of a quadratic strip theory formulated in the frequency domain. The springing response is thereby excited partly be resonance and partly by non-linear excitation. Special emphasis is given to the influence of springing on fatigue damage as the extreme responses even for very flexible ships are quite insensitive to the hull flexibility due to the high zero crossing periods associated with the extreme responses.

Jensen, JØrgen Juncher

1996-01-01

77

Uncertainty evaluation of fast reactor core seismic response  

International Nuclear Information System (INIS)

Response Surface Methodology (RSM) has been applied to a preliminary evaluation of the uncertainties on the seismic behaviour of the PEC fast reactor core. The structural analysis has been performed using the SAP IV code for the whole reactor block and CORALIE for the core. The calculated responses have been approximated with polynomial functions, whose adequacy has been tested by means of a further set of dynamic calculations. Finally the input uncertainties have been propagated by a Monte Carlo routine under different assumptions to assess the sensitivity of the output distribution with respect to the kind of input probability distributions. The paper describes the details of the study and demonstrates RSM adequacy. It also shows that, once a certain ground motion has been assumed, the core element natural frequencies and damping coefficients, as well as the vessel-core dynamic interaction parameters, are the main variables affecting the core response, which therefore need a sufficiently precise definition.

1983-01-01

78

Modeling the response of fast reactor fuel to accident transients  

International Nuclear Information System (INIS)

Progress in modeling the response of fast reactor fuel to accident transients is reported in four areas: fission gas release from grains and intragranular fuel swelling, fission gas redistribution and internal pressurization in solid fuel, fuel cracking models, and fuel plasticity modeling. Applications of models in the first two areas to assessment of the comparative dispersal potential of fuel in a CRBR hypothetical unprotected loss-of-flow accident with that in recent experiments are presented. It is concluded that the reactor case presents a greater dispersal potential.

1976-01-01

79

Seismic response analysis of the PEC fast reactor building  

International Nuclear Information System (INIS)

[en] A complete seismic response analysis taking into account the effects of soil-structure interaction is being performed for the PEC fast reactor, in order to compute the motion induced by the design earthquake at the vessel supporting structure. The mathematical models set up for the computation are calibrated using the data obtained through in situ experimental dynamic tests on the reactor building. The main aim of the analyses is to evaluate the safety margins present in the design calculations, performed with simplified methods and conservative assumptions. (orig.)

1985-01-01

80

Experimental implementation of a fast-response Hartmann sensor  

Energy Technology Data Exchange (ETDEWEB)

A fast-response automated Hartmann sensor is presented which describes the wavefront as an expansion in terms of the lowest aberrations. This sensor is capable of detecting tilt vectors of the wavefront with a dimensionality of 38 and a cyclicity of 625 Hz, and of expanding the monitored wavefront using a basis of 19 Zernike polynomials with a wavefront reconstruction frequency of 45 Hz. The possibility of using this sensor for determining the dynamic and statistical characteristics of light beams distorted by a turbulent atmosphere is also discussed. 8 refs.

Apollonov, V.V.; Vdovin, G.V.; Kiiko, V.V.; Murav' ev, S.V.; Chetkin, S.A. (Inst. Obshchei Fiziki, Moscow (Russian Federation))

1992-07-01

 
 
 
 
81

Fast Turbo Codes Concatenated With Space-Time Block Codes  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we investigate a new method for turbo codes which is dividing turbo encoder and decoder into several parallel coding and decoding blocks. These blocks work simultaneously and yield to much faster coding scheme in comparison with classical turbo codes. We compare simulation results of these new turbo codes with classical turbo codes to demonstrate that their performance is comparable with classical turbo codes, albeit they are much faster. Also, we introduce a new system by concatenating this fast turbo coding as outer code with Alamouti`s G2 space-time block coding scheme as inner code to achieve the benefits of both techniques including acceptable diversity and coding gain as well as short coding delay. We consider the performance of this new system in the block Rayleigh fading channel.

Fatemeh Afghah; Mehrdad Ardebilipour; Abolfazl Razi

2008-01-01

82

Effect of gadolinium covers on fast dosimeter response  

Energy Technology Data Exchange (ETDEWEB)

Gadolinium (Gd) has been used extensively at B and W Nuclear Technologies (BWNT) as a dosimetry shielding material for several years. Gadolinium has a significant cross section throughout the energy range of interest (i.e. above 1 MeV) in vessel fluence calculations. While Gd has a number of advantages as a dosimetry cover, it also has the potential for introducing a bias of unknown magnitude into the measured activities of covered fast response dosimeters such as U{sup 238} and iron. The Gd cover causes a reduction in the measured dosimeter activity, which means that the calculated fluxes normalized to those activities would be under-predicted. This is, of course, in the non-conservative direction. Since dosimeter covers are generally not included in the typical transport analysis model, corrections for this effect are not generally made. The calculated activities would not include the effects of the Gd while, of course, the measured activities would. The resulting calculation to measurement ratios, (C/M), which are used to remove biases in the calculated fluxes, would therefore be in error, in the non-conservative direction, by some undetermined amount. This study has determined the magnitude of the bias in the fast response dosimeters, U{sup 238} and iron caused by the absorption of fast (E > 1.0 MeV) neutrons in 2 mm (0.002 m) Gd covers. The results indicate that the bias is in the 2.9--3.4% range and that it is only a weak function of dosimeter material.

Rutherford, M.A.; King, S.Q. [B and W Nuclear Technologies, Lynchburg, VA (United States)

1994-12-31

83

UCP2 regulates the glucagon response to fasting and starvation.  

UK PubMed Central (United Kingdom)

Glucagon is important for maintaining euglycemia during fasting/starvation, and abnormal glucagon secretion is associated with type 1 and type 2 diabetes; however, the mechanisms of hypoglycemia-induced glucagon secretion are poorly understood. We previously demonstrated that global deletion of mitochondrial uncoupling protein 2 (UCP2(-/-)) in mice impaired glucagon secretion from isolated islets. Therefore, UCP2 may contribute to the regulation of hypoglycemia-induced glucagon secretion, which is supported by our current finding that UCP2 expression is increased in nutrient-deprived murine and human islets. Further to this, we created ?-cell-specific UCP2 knockout (UCP2AKO) mice, which we used to demonstrate that blood glucose recovery in response to hypoglycemia is impaired owing to attenuated glucagon secretion. UCP2-deleted ?-cells have higher levels of intracellular reactive oxygen species (ROS) due to enhanced mitochondrial coupling, which translated into defective stimulus/secretion coupling. The effects of UCP2 deletion were mimicked by the UCP2 inhibitor genipin on both murine and human islets and also by application of exogenous ROS, confirming that changes in oxidative status and electrical activity directly reduce glucagon secretion. Therefore, ?-cell UCP2 deletion perturbs the fasting/hypoglycemic glucagon response and shows that UCP2 is necessary for normal ?-cell glucose sensing and the maintenance of euglycemia.

Allister EM; Robson-Doucette CA; Prentice KJ; Hardy AB; Sultan S; Gaisano HY; Kong D; Gilon P; Herrera PL; Lowell BB; Wheeler MB

2013-05-01

84

UCP2 regulates the glucagon response to fasting and starvation.  

Science.gov (United States)

Glucagon is important for maintaining euglycemia during fasting/starvation, and abnormal glucagon secretion is associated with type 1 and type 2 diabetes; however, the mechanisms of hypoglycemia-induced glucagon secretion are poorly understood. We previously demonstrated that global deletion of mitochondrial uncoupling protein 2 (UCP2(-/-)) in mice impaired glucagon secretion from isolated islets. Therefore, UCP2 may contribute to the regulation of hypoglycemia-induced glucagon secretion, which is supported by our current finding that UCP2 expression is increased in nutrient-deprived murine and human islets. Further to this, we created ?-cell-specific UCP2 knockout (UCP2AKO) mice, which we used to demonstrate that blood glucose recovery in response to hypoglycemia is impaired owing to attenuated glucagon secretion. UCP2-deleted ?-cells have higher levels of intracellular reactive oxygen species (ROS) due to enhanced mitochondrial coupling, which translated into defective stimulus/secretion coupling. The effects of UCP2 deletion were mimicked by the UCP2 inhibitor genipin on both murine and human islets and also by application of exogenous ROS, confirming that changes in oxidative status and electrical activity directly reduce glucagon secretion. Therefore, ?-cell UCP2 deletion perturbs the fasting/hypoglycemic glucagon response and shows that UCP2 is necessary for normal ?-cell glucose sensing and the maintenance of euglycemia. PMID:23434936

Allister, Emma M; Robson-Doucette, Christine A; Prentice, Kacey J; Hardy, Alexandre B; Sultan, Sobia; Gaisano, Herbert Y; Kong, Dong; Gilon, Patrick; Herrera, Pedro L; Lowell, Bradford B; Wheeler, Michael B

2013-02-22

85

Interorgan coordination of the murine adaptive response to fasting.  

Science.gov (United States)

Starvation elicits a complex adaptive response in an organism. No information on transcriptional regulation of metabolic adaptations is available. We, therefore, studied the gene expression profiles of brain, small intestine, kidney, liver, and skeletal muscle in mice that were subjected to 0-72 h of fasting. Functional-category enrichment, text mining, and network analyses were employed to scrutinize the overall adaptation, aiming to identify responsive pathways, processes, and networks, and their regulation. The observed transcriptomics response did not follow the accepted "carbohydrate-lipid-protein" succession of expenditure of energy substrates. Instead, these processes were activated simultaneously in different organs during the entire period. The most prominent changes occurred in lipid and steroid metabolism, especially in the liver and kidney. They were accompanied by suppression of the immune response and cell turnover, particularly in the small intestine, and by increased proteolysis in the muscle. The brain was extremely well protected from the sequels of starvation. 60% of the identified overconnected transcription factors were organ-specific, 6% were common for 4 organs, with nuclear receptors as protagonists, accounting for almost 40% of all transcriptional regulators during fasting. The common transcription factors were PPAR?, HNF4?, GCR?, AR (androgen receptor), SREBP1 and -2, FOXOs, EGR1, c-JUN, c-MYC, SP1, YY1, and ETS1. Our data strongly suggest that the control of metabolism in four metabolically active organs is exerted by transcription factors that are activated by nutrient signals and serves, at least partly, to prevent irreversible brain damage. PMID:21393243

Hakvoort, Theodorus B M; Moerland, Perry D; Frijters, Raoul; Sokolovi?, Aleksandar; Labruyère, Wilhelmina T; Vermeulen, Jacqueline L M; Ver Loren van Themaat, Emiel; Breit, Timo M; Wittink, Floyd R A; van Kampen, Antoine H C; Verhoeven, Arthur J; Lamers, Wouter H; Sokolovi?, Milka

2011-03-10

86

Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments.  

Energy Technology Data Exchange (ETDEWEB)

Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different X-ray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

May, M; Halvorson, C; Perry, T; Weber, F; Young, P; Silbernagel, C

2008-05-06

87

Geosynchronous magnetic field responses to fast solar wind dynamic pressure enhancements: MHD field model  

Directory of Open Access Journals (Sweden)

Full Text Available We performed global MHD simulations of the geosynchronous magnetic field in response to fast solar wind dynamic pressure (Pd) enhancements. Taking three Pd enhancement events in 2000 as examples, we found that the main features of the total field B and the dominant component Bz can be efficiently predicted by the MHD model. The predicted B and Bz varies with local time, with the highest level near noon and a slightly lower level around mid-night. However, it is more challenging to accurately predict the responses of the smaller component at the geosynchronous orbit (i.e., Bx and By). In contrast, the limitations of T01 model in predicting responses to fast Pd enhancements are presented.

T. R. Sun; C. Wang; N. L. Borodkova; G. N. Zastenker

2012-01-01

88

Bubble masks for time-encoded imaging of fast neutrons.  

Energy Technology Data Exchange (ETDEWEB)

Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is induced-typically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixed blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gaps-bubbles-propagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.

Brubaker, Erik; Brennan, James S.; Marleau, Peter; Nowack, Aaron B.; Steele, John; Sweany, Melinda; Throckmorton, Daniel J.

2013-09-01

89

Fasting induces a biphasic adaptive metabolic response in murine small intestine  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The gut is a major energy consumer, but a comprehensive overview of the adaptive response to fasting is lacking. Gene-expression profiling, pathway analysis, and immunohistochemistry were therefore carried out on mouse small intestine after 0, 12, 24, and 72 hours of fasting. Results Intestinal weight declined to 50% of control, but this loss of tissue mass was distributed proportionally among the gut's structural components, so that the microarrays' tissue base remained unaffected. Unsupervised hierarchical clustering of the microarrays revealed that the successive time points separated into distinct branches. Pathway analysis depicted a pronounced, but transient early response that peaked at 12 hours, and a late response that became progressively more pronounced with continued fasting. Early changes in gene expression were compatible with a cellular deficiency in glutamine, and metabolic adaptations directed at glutamine conservation, inhibition of pyruvate oxidation, stimulation of glutamate catabolism via aspartate and phosphoenolpyruvate to lactate, and enhanced fatty-acid oxidation and ketone-body synthesis. In addition, the expression of key genes involved in cell cycling and apoptosis was suppressed. At 24 hours of fasting, many of the early adaptive changes abated. Major changes upon continued fasting implied the production of glucose rather than lactate from carbohydrate backbones, a downregulation of fatty-acid oxidation and a very strong downregulation of the electron-transport chain. Cell cycling and apoptosis remained suppressed. Conclusion The changes in gene expression indicate that the small intestine rapidly looses mass during fasting to generate lactate or glucose and ketone bodies. Meanwhile, intestinal architecture is maintained by downregulation of cell turnover.

Sokolovi? Milka; Wehkamp Diederik; Sokolovi? Aleksandar; Vermeulen Jacqueline; Gilhuijs-Pederson Lisa A; van Haaften Rachel IM; Nikolsky Yuri; Evelo Chris TA; van Kampen Antoine HC; Hakvoort Theodorus BM; Lamers Wouter H

2007-01-01

90

Fast response characteristics of hydrogen sensors based on Pd nanoparticle films with controlled coverage  

International Nuclear Information System (INIS)

[en] The response time of the quantum conductance-based hydrogen sensor fabricated from films consisting of closely spaced palladium nanoparticles formed with cluster beam deposition was investigated. The dependence of the response time on the coverage-regulated nanoparticle size, as well as the hydrogen pressure, was determined. At low hydrogen pressure, the response time is dominated by the hydriding time of the larger Pd nanoparticles. Fast response as short as 3 s to 1,000 Pa H2 could be realized with the lower coverage nanoparticle film, with a sensitive change of the relative conductance as high as 70 %. At 10 kPa hydrogen pressure, subsecond hydrogen response could be realized. With the increase of the hydrogen pressure, the response time of the devices becomes longer and longer as determined by the hydriding time of the Pd nanoparticles involved in the smaller size population of the size distribution, and approaches the same value for the hydrogen sensors with different nanoparticle coverages. The abnormal increase of the response time accompanied by the formation of the ? + ? coexistence phase of PdHx was also investigated.

2013-01-01

91

Seismic response analysis of the PEC fast reactor building  

International Nuclear Information System (INIS)

[en] In order to compute the motion induced by the design earthquakes at the vessel supporting structure, a seismic response analysis was performed for the PEC fast reactor, taking into account the effects of soil-structure interaction by use of experimentally determined soil parameters. The main aim of he analysis was to evaluate the safety margins present in the design calculations. A detailed 3D finite element model was set up for fixed base analysis; from the results of the 3D model a simplified equivalent model of the structure was then derived for soil-structure interaction analysis. The mathematical model was validated and calibrated by using the results of the experimental dynamic tests performed on the reactor building. The results have shown the adequacy of the computation methodologies, and in particular of those on the use of the equivalent model. (author)

1988-01-01

92

Seismic response analysis of the PEC fast reactor building  

Energy Technology Data Exchange (ETDEWEB)

In order to compute, at the vessel supporting structure, the motion induced by design earthquakes, a seismic response analysis was performed for the PEC fast reactor. Experimentally determined soil parameters were used to take into account the effects of soil-structure interactions. The main aim of the analysis was to evaluate the safety margins present in the design calculations. A detailed 3D finite element model was set up for fixed base analysis; from the results of the 3D model a simplified equivalent model of the structure was then derived for soil-structure interaction analysis. The mathematical model was validated and calibrated by using the results of the experimental dynamic tests performed on the reactor building. The results have shown the adequacy of the computational methodologies and, in particular, of those based on the use of the equivalent model.

Bonaldi, P.; Muzzi, F.; Orsi, R.; Ruggeri, G.; Martelli, A.; Masoni, P. (ISMES SpA, Bergamo (Italy); ENEA, Bologna (Italy))

1988-01-01

93

Fast Intrinsic Mode Decomposition of Time Series Data  

CERN Document Server

A fast convergent iterative method is introduced in this paper to find the intrinsic mode function (IMF) components of time series data, which is faster and more predictable than the Empirical Mode Decomposition method devised by the author of Hilbert Huang Transform. The method iteratively adjust the control points on the data function corresponding to the extrema of the refining IMF, the control points of the residue function are calculated as the median of the straight line segments passing through the data control points, the residue function is then constructed as the cubic spline function of the median points. The initial residue function is simply constructed as the straight line segments passing through the extrema of the differential of the data function. The refining IMF is the difference between the data function and the improved residue function. The IMF found can also reveal the riding waves on the steep edge of the data. The program to demonstrate the method is distributed under BSD license.

Lu, Louis Yu

2008-01-01

94

Using ferrite as a fast switch for improving rise time of IPNS extraction kicker  

International Nuclear Information System (INIS)

The Kicker system is used to extract beam from the Rapid Cycling Synchrotron (RCS). The Kicker consists of four identical pulse circuits, each providing over 3.8 kA to each magnet winding. The magnet length is restricted to the space between vacuum bellows attached to the ring magnets. This leaves 0.89 m for the magnet. To keep the voltage low the magnet conductor is broke up into 4, 1/4-turn magnet windings. Each pulse circuit consists of a Pulse Forming Network (PFN) that is charged to 50 KV. The PFN is discharged through a thyratron into a 6.3-ohm transmission line to one of the magnet windings. Our system has always had marginal rise time of around 100 ns. Although the thyratron switching time is much faster than this, losses in the transmission lines cause the slower response. By using ferrite to make a fast switch between the transmission lines and the magnet, the rise time in the magnet can be reduced. To make a fast ferrite switch, the saturation point must carefully be chosen. Parameters related to choosing the proper ferrite to provide fast saturation, at the correct current will be discussed.

2004-01-01

95

Using ferrite as a fast switch for improving rise time of IPNS extraction kicker.  

Energy Technology Data Exchange (ETDEWEB)

The Kicker system is used to extract beam from the Rapid Cycling Synchrotron (RCS). The Kicker consists of four identical pulse circuits, each providing over 3.8 kA to each magnet winding. The magnet length is restricted to the space between vacuum bellows attached to the ring magnets. This leaves 0.89 m for the magnet. To keep the voltage low the magnet conductor is broke up into 4, 1/4-turn magnet windings. Each pulse circuit consists of a Pulse Forming Network (PFN) that is charged to 50 KV. The PFN is discharged through a thyratron into a 6.3-ohm transmission line to one of the magnet windings. Our system has always had marginal rise time of around 100 ns. Although the thyratron switching time is much faster than this, losses in the transmission lines cause the slower response. By using ferrite to make a fast switch between the transmission lines and the magnet, the rise time in the magnet can be reduced. To make a fast ferrite switch, the saturation point must carefully be chosen. Parameters related to choosing the proper ferrite to provide fast saturation, at the correct current will be discussed.

Dooling, J. C.; Intense Pulsed Neutron Source

2004-01-01

96

The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons.  

UK PubMed Central (United Kingdom)

This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO(2) optical fibres subjected to (241)AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the (241)AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being made to entirely enclose the fibres). The neutron irradiations were performed for exposure times of 1-, 2-, 3-, 5- and 7-days in a neutron tank filled with water. In this study, use was also made of the Monte Carlo N-particle (MCNP) code version 5 (V5) to simulate the neutron irradiations experiment. It was found that the commercially available Ge-doped and Al-doped optical fibres show a linear dose response subjected to fast neutrons from (241)AmBe source up to seven days of irradiations. The simulation performed using MCNP5 also exhibits a similar pattern, albeit differing in sensitivity. The TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre, the total absorption cross section for Ge in both the fast and thermal neutrons region being some ten times greater than that of Al.

Hashim S; Bradley DA; Saripan MI; Ramli AT; Wagiran H

2010-04-01

97

Comparison study of fast responses in confined plasmas with diffusivity models  

International Nuclear Information System (INIS)

An equation which includes the non-local effect in the heat flux is introduced to study the transient transport phenomena. A non-local heat flux, which is expressed in terms of the integral equation, is superimposed on the conventional form of the heat flux. This model is applied to describe the fast responses in the transition from Low confinement mode (L-mode) to High confinement mode (H-mode) and in the heating power switching. Examples of diffusivity models are chosen, i.e., constant, Bohm and Rebut-Lallia-Watkins (RLW) model and the comparison study is done. A small reaction of non-local component in the heat flux is found to be very effective in reducing the response time. Independent of the diffusivity models, the fast transient transport in the heat pulse propagation is reproduced based on this non-local model. (author)

2000-01-01

98

Comparison study of fast responses in confined plasmas with diffusivity models  

Energy Technology Data Exchange (ETDEWEB)

An equation which includes the non-local effect in the heat flux is introduced to study the transient transport phenomena. A non-local heat flux, which is expressed in terms of the integral equation, is superimposed on the conventional form of the heat flux. This model is applied to describe the fast responses in the transition from Low confinement mode (L-mode) to High confinement mode (H-mode) and in the heating power switching. Examples of diffusivity models are chosen, i.e., constant, Bohm and Rebut-Lallia-Watkins (RLW) model and the comparison study is done. A small reaction of non-local component in the heat flux is found to be very effective in reducing the response time. Independent of the diffusivity models, the fast transient transport in the heat pulse propagation is reproduced based on this non-local model. (author)

Iwasaki, Takuya [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka (Japan); Itoh, Sanae-I.; Yagi, Masatoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan)

2000-03-01

99

Response times in email interchange  

CERN Multimedia

An alternative interpretation of e-mail interchange data presented by J.P. Eckmann, E. Moshes and D. Sergi in a recent preprint (cond-mat/0304433) is presented. The data agrees with the proposed frame work prosposed to explain two recent experiments on the response of ``internauts'' to a news publication.

Johansen, A

2003-01-01

100

A measurement of the response to fast neutrons of several materials dosemeters  

International Nuclear Information System (INIS)

The response to fast neutrons was measured for three types of materials testing dosemeters: fast neutron dosimetry silicon diodes; beryllia, alumina and calcium fluoride TLDs; graphite walled ionisation chambers. The calibrations were made using a 3MW positive ion accelerator. The arrangement of the target, beam monitor and devices is described, and the measured fast neutron sensitivities are presented. (UK).

1986-01-01

 
 
 
 
101

Fast and accurate calculations for cumulative first-passage time distributions in Wiener diffusion models  

DEFF Research Database (Denmark)

We propose an improved method for calculating the cumulative first-passage time distribution in Wiener diffusion models with two absorbing barriers. This distribution function is frequently used to describe responses and error probabilities in choice reaction time tasks. The present work extends related work on the density of first-passage times [Navarro, D.J., Fuss, I.G. (2009). Fast and accurate calculations for first-passage times in Wiener diffusion models. Journal of Mathematical Psychology, 53, 222-230]. Two representations exist for the distribution, both including infinite series. We derive upper bounds for the approximation error resulting from finite truncation of the series, and we determine the number of iterations required to limit the error below a pre-specified tolerance. For a given set of parameters, the representation can then be chosen which requires the least computational effort.

Blurton, S.P.; Kesselmeier, M.

2012-01-01

102

Response of a single-crystal diamond detector to fast neutrons  

Science.gov (United States)

Bi-parametric (neutron time of flight and deposited energy) measurements using a Single-crystal Diamond Detector (4.5 × 4.5 × 0.5 mm3 active volume) were performed at the n_TOF neutron facility at CERN. The time structure of the neutron beam combined with the long flight path allowed for measurements of the diamond detector response to quasi monoenergetic neutrons in the energy range up to 40 MeV. Deposited energy spectra were compared to MCNPX simulations using different cross section libraries. The results can be used for the interpretation of Single-crystal Diamond Detector measurements of fast neutrons at spallation neutron sources.

Rebai, M.; Milocco, A.; Giacomelli, L.; Perelli Cippo, E.; Tardocchi, M.; Fazzi, A.; Pietropaolo, A.; Gorini, G.

2013-10-01

103

Modeling of Responses and Response Times with the Package cirt  

Directory of Open Access Journals (Sweden)

Full Text Available In computerized testing, the test takers’ responses as well as their response times on the items are recorded. The relationship between response times and response accuracies is complex and varies over levels of observation. For example, it takes the form of a tradeoff between speed and accuracy at the level of a fixed person but may become a positive correlation for a population of test takers. In order to explore such relationships and test hypotheses about them, a conjoint model is proposed. Item responses are modeled by a two-parameter normal-ogive IRT model and response times by a lognormal model. The two models are combined using a hierarchical framework based on the fact that response times and responses are nested within individuals. All parameters can be estimated simultaneously using an MCMC estimation approach. A R-package for the MCMC algorithm is presented and explained.

Jean-Paul Fox; Rinke Klein Entink; Wim van der Linden

2007-01-01

104

A time-gating scintillation detector for the measurement of laser-induced fast neutrons.  

UK PubMed Central (United Kingdom)

A time-gating scintillation detector, in which a fast high voltage switch is used for gating a channel photomultiplier, was developed for a measurement of laser-induced fast neutrons. The x rays generated from the intense femtosecond laser and the solid target interactions were suppressed selectively and a time-of-flight signal of a laser-generated fast neutron was measured effectively. The detector was used successfully to measure the neutron yield of a femtosecond, deuterated, polystyrene plasma.

Lee S; Park S; Yea KH; Cha H

2009-06-01

105

Driving fast-spiking cells induces gamma rhythm and controls sensory responses.  

Science.gov (United States)

Cortical gamma oscillations (20-80 Hz) predict increases in focused attention, and failure in gamma regulation is a hallmark of neurological and psychiatric disease. Current theory predicts that gamma oscillations are generated by synchronous activity of fast-spiking inhibitory interneurons, with the resulting rhythmic inhibition producing neural ensemble synchrony by generating a narrow window for effective excitation. We causally tested these hypotheses in barrel cortex in vivo by targeting optogenetic manipulation selectively to fast-spiking interneurons. Here we show that light-driven activation of fast-spiking interneurons at varied frequencies (8-200 Hz) selectively amplifies gamma oscillations. In contrast, pyramidal neuron activation amplifies only lower frequency oscillations, a cell-type-specific double dissociation. We found that the timing of a sensory input relative to a gamma cycle determined the amplitude and precision of evoked responses. Our data directly support the fast-spiking-gamma hypothesis and provide the first causal evidence that distinct network activity states can be induced in vivo by cell-type-specific activation. PMID:19396156

Cardin, Jessica A; Carlén, Marie; Meletis, Konstantinos; Knoblich, Ulf; Zhang, Feng; Deisseroth, Karl; Tsai, Li-Huei; Moore, Christopher I

2009-04-26

106

Digitally Controlled Point of Load Converter with Very Fast Transient Response  

DEFF Research Database (Denmark)

This paper presents a new Digital Self-Oscillating Modulator (DiSOM) that allows the duty cycle to be changed instantly. The DiSOM modulator is shown to have variable switching that is a function of the duty cycle. Compared to a more traditional digital PWM modulator based on a counter and comparator the DiSOM modulator allows the sampling frequency of the output voltage control loop to be higher than the switching frequency of the power converter, typically a DC/DC converter. The features of the DiSOM modulator makes it possible to design a digitally controlled DC/DC converter with linear voltage mode control and very fast transient response. The DiSOM modulator is combined with a digital PID compensator algorithm is implemented in a hybrid CPLD/FPGA and is used to control a synchronous Buck converter, which is used in typical Point of Load applications. The computational time is only three clock cycles from the time the A/D converter result is read by the control algorithm to the time the duty cycle command is updated. A typical POL converter has been built and the experimental results show that the transient response of the converter is very fast. The output voltage overshoot is only 2.5% of the nominal output voltage when a load step of 50% - 100% of nominal output current is applied to the converter. The settling time is approximately 8 PWM cycles.

Jakobsen, Lars TØnnes; Andersen, Michael Andreas E.

2007-01-01

107

Fast quasi-explicit finite difference simulation of electrochemical responses initiated by a discontinuous perturbation  

Energy Technology Data Exchange (ETDEWEB)

Commencing in the early 60s the application of explicit finite difference (EFD) methods to the analysis of electrochemical problems paralleled the development and availability of fast, main-frame, digital computers. The appeal of the EFD method has been its simplicity of principle and of application. EFD algorithms, however, are notoriously inefficient for solving certain types of stiff problems (e.g., problems involving a wide dynamic range of time constants). In this presentation the author discusses the principles and some applications of a fast quasi-explicit finite difference (FQEFD) method in which the computational speed is enhanced, by many orders of magnitude in some cases, without compromising the user friendliness which has popularized the EFD method. The method is designed to treat electrochemical responses to a discontinuous (e.g, chronoamperometric) perturbation and utilizes the DuFort-Frankel algorithm (1) with exponentially expanding space (2) and exponentially expanding time grids. (A previously published version of the FQEFD method (3,4) was designed to treat electrochemical responses to a continuous (e.g., cyclic voltammetric) perturbation and utilizes the DuFort-Frankel (3) algorithm in conjunction with an exponentially expanding space grid and a uniform time grid. The development of the basic FQEFD equations was presented there). The protocol for introducing the expanding time grid is straightforward and is discussed. 7 refs., 1 fig. 1 tab.

Feldberg, S.W.

1991-01-01

108

Sufficient Conditions for Fast Switching Synchronization in Time Varying Network Topologies  

CERN Document Server

In previous work, empirical evidence indicated that a time-varying network could propagate sufficient information to allow synchronization of the sometimes coupled oscillators, despite an instantaneously disconnected topology. We prove here that if the network of oscillators synchronizes for the static time-average of the topology, then the network will synchronize with the time-varying topology if the time-average is achieved sufficiently fast. Fast switching, fast on the time-scale of the coupled oscillators, overcomes the descychnronizing decoherence suggested by disconnected instantaneous networks. This result agrees in spirit with that of where empirical evidence suggested that a moving averaged graph Laplacian could be used in the master-stability function analysis. A new fast switching stability criterion here-in gives sufficiency of a fast-switching network leading to synchronization. Although this sufficient condition appears to be very conservative, it provides new insights about the requirements fo...

Stilwell, D; Roberson, D G; Stilwell, Daniel; Bollt, Erik

2005-01-01

109

Linking survival and biomarker responses over time.  

UK PubMed Central (United Kingdom)

The practical usefulness of biomarkers is limited by the complexity of linking their responses to life-history traits of the organisms (e.g., survival, growth, reproduction) over time. Here the authors present a first attempt to model biomarker responses and survival over time simultaneously with a toxicokinetic-toxicodynamic approach. Even though more work is clearly needed, the present study provides a novel direction for interpreting biomarker responses and dynamically linking them to life-history traits.

Jager T; Hansen BH

2013-08-01

110

Impaired fasting glucose individuals: their response to oral glucose challenge  

International Nuclear Information System (INIS)

To determine the frequency of Impaired Fasting Glucose (IFG) individuals in symptom free adults and their 2-h PG (two-hour plasma glucose) concentrations in standard Oral Glucose Tolerance Test (OGTT) with 75-g glucose. Fasting plasma glucose (FPG) of 859 symptom free adults was checked. Of them, 344(40%) were found to have IFG, who were subjected to standard OGTT with 75-g glucose and their 2-h PG results were recorded. Frequency distribution of FPG of 859 symptom free adults showed, 455(53%) were Normal Fasting Glucose (NFG 7.0 mmol/l). The difference in frequency of three groups of FPG was statistically significant (p

2006-01-01

111

A display module implemented by the fast high-temperatue response of carbon nanotube thin yarns.  

UK PubMed Central (United Kingdom)

Suspending superaligned multiwalled carbon nanotube (MWCNT) films were processed into CNT thin yarns, about 1 ?m in diameter, by laser cutting and an ethanol atomization bath treatment. The fast high-temperature response under a vacuum was revealed by monitoring the incandescent light with a photo diode. The thin yarns can be electrically heated up to 2170 K in 0.79 mS, and the succeeding cool-down time is 0.36 mS. The fast response is attributed to the ultrasmall mass of the independent single yarn, large radiation coefficient, and improved thermal conductance through the two cool ends. The millisecond response time makes it possible to use the visible hot thin yarns as light-emitting elements of an incandescent display. A fully sealed display with 16 × 16 matrix was successfully fabricated using screen-printed thick electrodes and CNT thin yarns. It can display rolling characters with a low power consumption. More applications can be further developed based on the addressable CNT thermal arrays.

Wei Y; Liu P; Jiang K; Fan S

2012-05-01

112

A display module implemented by the fast high-temperatue response of carbon nanotube thin yarns.  

Science.gov (United States)

Suspending superaligned multiwalled carbon nanotube (MWCNT) films were processed into CNT thin yarns, about 1 ?m in diameter, by laser cutting and an ethanol atomization bath treatment. The fast high-temperature response under a vacuum was revealed by monitoring the incandescent light with a photo diode. The thin yarns can be electrically heated up to 2170 K in 0.79 mS, and the succeeding cool-down time is 0.36 mS. The fast response is attributed to the ultrasmall mass of the independent single yarn, large radiation coefficient, and improved thermal conductance through the two cool ends. The millisecond response time makes it possible to use the visible hot thin yarns as light-emitting elements of an incandescent display. A fully sealed display with 16 × 16 matrix was successfully fabricated using screen-printed thick electrodes and CNT thin yarns. It can display rolling characters with a low power consumption. More applications can be further developed based on the addressable CNT thermal arrays. PMID:22494045

Wei, Yang; Liu, Peng; Jiang, Kaili; Fan, Shoushan

2012-04-20

113

Ultraviolet fast-response photoelectric effects in LiTaO3 single crystal  

Science.gov (United States)

The photoelectric effects of LiTaO3 (LTO) single crystals are experimentally studied with two kinds of LTO wafers, 10° tilted and untilted, at room temperature. A transient open-circuit photoelectrical response of 143 ps rise time is observed in the 10° tilted LTO when a 266 nm pulsed laser with a duration of 25 ps is irradiated directly onto the LTO surface. The untilted LTO with interdigitated electrodes of 10 µm finger width and 10 µm interspacing exhibits a linear dependence on the applied bias and power density of incident light, a response peak at about 235 nm and a sharp cutoff at about 270 nm. The noise current is only 61 pA at 20 V bias under the illumination of sunlight outdoors at midday. The experimental results suggest the promising application of the LTO single crystal in UV detection, in particular, as a solar-blind fast-response photodetector.

Guo, Er-Jia; Xing, Jie; Lu, Hui-Bin; Jin, Kui-Juan; Wen, Juan; Yang, Guo-Zhen

2010-01-01

114

Improvements in sensitivity and response times of photon imaging tubes  

Energy Technology Data Exchange (ETDEWEB)

In order to increase the transmission and speed of response of fibreoptic faceplates in imaging tubes a method is reported which used metallization only of the interfibre glass regions. This offers maximum transmission of the fibres whilst supporting high conductivity, as required for fast response times. An initial metal layer was laser ablated with light directed through the fibre array to provide a self-aligning process. Transmission has been increased threefold compared with earlier metal layer methods, which is of particular value for long wavelength sensitivity where the cathode efficiency is low. By allowing the use of more conductive pathways the more critical values of the response times have been reduced from the nanosecond to the picosecond range for these imaging tubes.

Townsend, P D [Science and Technology, University of Sussex, Brighton, BN1 9QH (United Kingdom); Hallensleben, S [Science and Technology, University of Sussex, Brighton, BN1 9QH (United Kingdom); Phillips, M [Science and Technology, University of Sussex, Brighton, BN1 9QH (United Kingdom); Downey, R J [Science and Technology, University of Sussex, Brighton, BN1 9QH (United Kingdom); Brooks, R J [Photek Ltd, 26 Castleham Rd, St Leonards on Sea, Sussex, TN38 9NS (United Kingdom); Howorth, J [Photek Ltd, 26 Castleham Rd, St Leonards on Sea, Sussex, TN38 9NS (United Kingdom); Milnes, J [Photek Ltd, 26 Castleham Rd, St Leonards on Sea, Sussex, TN38 9NS (United Kingdom)

2006-10-21

115

EGR Control for Emisson Reduction Using Fast Response Sensors - Phase 1A  

Energy Technology Data Exchange (ETDEWEB)

The overall objective of this project was to develop exhaust gas recirculation (EGR) control strategies using fast-response Particulate Matter (PM) sensors and NOx sensors to improve the quality of particulate and gaseous emissions from diesel engines. This project initially comprised three phases: (1) Phase IA - sensor requirements to meet PM sensor specifications, NOx sensor assessment, and initial model development for EGR control; (2) Phase IB - continue development on PM and NOx sensors, integrate the sensor signals into the control simulations, and finalize model development for control strategies; and (3) Phase II - validation testing of the control strategies. Only Phase 1A was funded by DOE and executed by Honeywell. The major objectives of Phase 1A of the project included: (1) Sensor validation and operation of fast-response PM and NOx sensors; (2) Control system modeling of low-pressure EGR controls, development of control strategies, and initial evaluation of these models and strategies for EGR control in diesel engines; (3) Sensor testing to understand applicability of fast-response PM sensors in determining loading rates of the particle trap; and (4) Model validation and sensor testing under steady-state and transient operational conditions of actual engines. In particular, specific objectives included demonstration of: (1) A PM sensor response time constant (T10 - T90) of better than 100 milliseconds (msec); (2) The ability to detect PM at concentrations from 0.2 to 2 Bosch smoke number (BSN) or equivalent; (3) PM sensor accuracy to within 20% BSN over the entire range of operation; and (4) PM sensor repeatability to within 10% over the PM entire sensor range equivalent to a BSN of 0.2 to 2.

Gravel, Roland; Conley, Jason; Kittelson, David

2008-09-30

116

Sensor response time verification. Final report  

International Nuclear Information System (INIS)

[en] The final results of Research Project RP503-1 concerning pressure and differential pressure sensor response time verification are presented. A selected sample of nine typical process sensors have been tested using a specially designed hydraulic signal generator and detailed test procedures to verify their ability to produce valid sensor response time measurements in a simulated in-situ configuration. Design details are provided concerning the hydraulic signal generator, and generic test procedures are included to permit the utility user to quickly implement a response time measurement program for these and other similar sensor types

1976-01-01

117

Application of piezoelectric stress gauges to the measurement of fast-rise-time multimegampere electric currents  

Energy Technology Data Exchange (ETDEWEB)

Modeling of load behavior in Z-pinch plasma radiation sources driven by high current generators requires accurate measurement of fast-rise-time multimegampere electrical currents close to the load. Using a novel application of high pressure technology, we have demonstrated that fast-response piezoelectric stress transducers can measure such currents under conditions of extremely high current density, induced electric fields, and bremsstrahlung radiation where conventional current diagnostics fail. Large signal, nanosecond-time-resolution lithium niobate piezoelectric stress gauges are employed to directly measure the magnetic pressure B{sup 2}/2{mu}{sub 0} = {mu}{sub 0}I{sup 2}/8{pi}{sup 2}r{sup 2} generated at radius r by a current I flowing in a radial transmission line near the load of a pulsed power current source. With a current diagnostic consisting of a pure tungsten electrode on a Y-cut lithium niobate stress gauge, current densities up to 1/2{pi}cr = 78MA/m can be measured before the electrode yield strength and piezoelectric operating stress limit are exceeded. Based on this work, we have developed a compact modular current probe for use on the high current (20--25 MA) DECADE simulator being constructed for the Defense Nuclear Agency. We also describe recent work extending this measurement technique to higher current densities (125 MA/m) using a cooper-sapphire electrode impedance stack on an X-cut quartz piezoelectric element.

Hanson, D.L.; Spielman, R.B.; Seamen, J.F. [Sandia National Labs., Albuquerque, NM (United States); Struve, K.W. [Mission Research Corp., Albuquerque, NM (United States)

1993-07-01

118

Thermo-responsive Hercosett/Poly(N-isopropylacrylamide) films: a new, fast, optically responsive coating.  

UK PubMed Central (United Kingdom)

Poly(N-isopropylacrylamide) (PNIPAM) is a common thermo-responsive, water-soluble polymer, while Hercosett is a cationic resin commonly employed in the paper industry. In this paper, Hercosett™ and poly(N-isopropylacrylamide) (PNIPAM) nanoparticles were used to prepare composite films that show thermo-responsive behavior and swelling-shrinking properties in water. First, size-controlled PNIPAM hydrogel nanoparticles were synthesized. These were then embedded within a matrix of the cationic resin Kymene 577H by film casting. The distribution of nanoparticles in the resin film was investigated. The thermo-responsive properties of the as-synthesized PNIPAM hydrogel nanoparticles and of the composite films were characterized together with the repeatability of the swelling-shrinking cycles. The presence of nanoparticles endowed the film with highly enhanced water retention (in comparison with resin-only films) and, most importantly, thermo-responsiveness. A very fast optical and morphological response was in fact observed. Due to the dual (optical and morphological) response, this new system is suitable for applications in optical or morphological actuation and gating.

Wang J; Sutti A; Wang X; Lin T

2012-03-01

119

Significance of time dependent HDPE pipe response  

Energy Technology Data Exchange (ETDEWEB)

New computer models for high density polyethylene (HDPE) were used to examine time dependent pipe response in the field. One typical pipe was considered under various loading and burial conditions. The study showed that time dependent deflection of buried HDPE pipe was primarily controlled by the surrounding soil, rather than by the viscoelastic pipe response. Significant stress relaxation occurred in the pipe as a result of the time dependent HDPE characteristics and the progressive development of positive arching over time. 15 refs., 4 figs.

Moore, I.D.; Hu, F. [University of Western Ontario, London, ON (Canada). Dept. of Civil Engineering

1995-12-31

120

Fast-slow coincidence systems with very high time resolution  

International Nuclear Information System (INIS)

The measuring of very short times has recently become increasingly important. In this paper the authors describe their studies on the various parts of a timing system in an attempt to improve its parameters. The detector system, i.e. the transit time differences of the photomultipliers, the construction of the divider network, the various types of timing discriminators, the time-to-pulse height converters and the gating system were investigated. Two types of constant fraction discriminators are introduced: one for general timing applications, the other placed inside the detector head for positron lifetime measurements. (author).

1981-01-01

 
 
 
 
121

Infants' brain responses for speech sound changes in fast multifeature MMN paradigm.  

UK PubMed Central (United Kingdom)

OBJECTIVE: We investigated whether newborn speech-sound discrimination can be studied in 40 min using fast multifeature mismatch negativity (MMN) paradigm and do the results differ from those obtained with the traditional oddball paradigm. METHODS: Newborns' MMN responses to five types of changes (consonant identity, F0, intensity, vowel duration and vowel identity) were recorded in the multifeature group (N=15) and vowel duration and vowel identity changes in the oddball group (N=13), after which the MMNs from both groups were compared with each others. RESULTS: Statistically significant MMNs in the 190-600 ms time range from the stimulus onset were found for most change types in both paradigms. Newborn MMN responses were predominantly positive but a small number of participants elicited negative MMNs instead. MMN amplitudes did not differ between the multifeature and oddball groups. CONCLUSIONS: Newborn speech-sound discrimination can be assessed in a short recording time using the fast multifeature paradigm. SIGNIFICANCE: The paradigm presented here can be used to record extensive auditory discrimination profiles in newborns and assess development of speech-sound discrimination and its difficulties.

Partanen E; Pakarinen S; Kujala T; Huotilainen M

2013-08-01

122

The Fast Tracker Real Time Processor: high quality real-time tracking at ATLAS  

CERN Multimedia

As the LHC luminosity is ramped up to the design level of 1x1034 cm?2 s?1 and beyond, the high rates, multiplicities, and energies of particles seen by the detectors will pose a unique challenge. Only a tiny fraction of the produced collisions can be stored on tape and immense real-time data reduction is needed. An effective trigger system must maintain high trigger efficiencies for the most important physics and at the same time suppress the enormous QCD backgrounds. This requires massive computing power to minimize the online execution time of complex algorithms. A multi-level trigger is an effective solution for an otherwise impossible problem. The Fast Tracker (FTK)[1], [2] is a proposed upgrade to the current ATLAS trigger system that will operate at full Level-1 output rates and provide high quality tracks reconstructed over the entire detector by the start of processing in Level-2. FTK is a dedicated Super Computer based on a mixture of advanced technologies. The architecture broadly employs powerf...

Stabile, A; The ATLAS collaboration

2011-01-01

123

A fasting-responsive signaling pathway that extends life span in C. elegans.  

UK PubMed Central (United Kingdom)

Intermittent fasting is one of the most effective dietary restriction regimens that extend life span in C. elegans and mammals. Fasting-stimulus responses are key to the longevity response; however, the mechanisms that sense and transduce the fasting stimulus remain largely unknown. Through a comprehensive transcriptome analysis in C. elegans, we find that along with the FOXO transcription factor DAF-16, AP-1 (JUN-1/FOS-1) plays a central role in fasting-induced transcriptional changes. KGB-1, one of the C. elegans JNKs, acts as an activator of AP-1 and is activated in response to fasting. KGB-1 and AP-1 are involved in intermittent fasting-induced longevity. Fasting-induced upregulation of the components of the SCF E3 ubiquitin ligase complex via AP-1 and DAF-16 enhances protein ubiquitination and reduces protein carbonylation. Our results thus identify a fasting-responsive KGB-1/AP-1 signaling pathway, which, together with DAF-16, causes transcriptional changes that mediate longevity, partly through regulating proteostasis.

Uno M; Honjoh S; Matsuda M; Hoshikawa H; Kishimoto S; Yamamoto T; Ebisuya M; Yamamoto T; Matsumoto K; Nishida E

2013-01-01

124

Sensor response time monitoring using noise analysis  

International Nuclear Information System (INIS)

[en] Random noise techniques in nuclear power plants have been developed for system surveillance and for analysis of reactor core dynamics. The noise signals also contain information about sensor dynamics, and this can be extracted using frequency, amplitude and time domain analyses. Even though noise analysis has been used for sensor response time testing in some nuclear power plants, an adequate validation of this method has never been carried out. This paper presents the results of limited work recently performed to examine the validity of the noise analysis for sensor response time testing in nuclear power plants. The conclusion is that noise analysis has the potential for detecting gross changes in sensor response but it cannot be used for reliable measurement of response time until more laboratory and field experience is accumulated. The method is more advantageous for testing pressure sensors than it is for temperature sensors. This is because: 1) for temperature sensors, a method called Loop Current Step Response test is available which is quantitatively more exact than noise analysis, 2) no method currently exists for on-line testing of pressure transmitters other than the Power-Interrupt test which is applicable only to force balance pressure transmitters, and 3) pressure sensor response time is affected by sensing line degradation which is inherently taken into account by testing with noise analysis. (author)

1988-01-01

125

A fast response variable optical attenuator based on blue phase liquid crystal.  

UK PubMed Central (United Kingdom)

Blue phase liquid crystals (BPLCs) are promising candidates for next generation display thanks to their fast response and quasi-isotropic optical properties. By taking these advantages, we propose to introduce the material into fiber-optic applications. As an example, a BPLC based variable optical attenuator (VOA) is demonstrated with a polarization independent design. The device shows normally-off feature when no field is applied. Response time down to submillisecond scale is achieved in switching between two arbitrary attenuation states. The attenuation range is also measured from 1480 to 1550 nm, which cover the whole telecomm S-band and part of the C-band. The overall performances reach the requirements for practical use; while still have room for further improvement. Through this example, the applicability of BPLC in fiber-optic devices is presented, which may impel the development of many other photonic applications from infrared to even microwave regions.

Zhu G; Wei BY; Shi LY; Lin XW; Hu W; Huang ZD; Lu YQ

2013-03-01

126

Fast-response light-emitting electrochemical cells based on neutral iridium(III) complex  

Energy Technology Data Exchange (ETDEWEB)

In this study, light-emitting electrochemical cells (LECs) based on neutral iridium(III) bis(2-phenylquinolato-N,C{sup 2'})(3-isoquinaldate) were fabricated. An admixed solid supporting electrolyte tetra-n-butylammonium tetrafluoroborate (TBABF{sub 4}) is employed in the emitting layer, and it facilitates charge injection with decreasing the potential barrier under a biased voltage. The cells generate an electroluminescence (EL) of 300 cd m{sup -2} at - 3.8 V. When the molar ratio of TBABF{sub 4} to the complex in the device was 2:1, a fast EL response of 0.8 s was obtained at - 4.0 V after the several times of preconditioning. As the quantity of the supporting electrolyte increased, a faster and brighter EL response was obtained. (author)

Shin, Ik-Soo; Lim, Hong-Chul; Oh, Jeong-Wook; Lee, Jin-Kyu [Department of Chemistry, Seoul National University (Korea, Republic of); Kim, Tae Hyun [Department of Chemistry, Soonchunhyang University, Asan (Korea, Republic of); Kim, Hasuck [Department of Chemistry, Seoul National University (Korea, Republic of); Department of Energy Systems Engineering, DGIST, Daegu (Korea, Republic of)

2011-01-15

127

ARMA sensor response time analysis. Final report  

International Nuclear Information System (INIS)

[en] The Auto Regressive Moving Average time series analyis method was investigated for Resistance Temperature Detector (RTD) and pressure sensor response time measurement. The theoretical background, data acquisition, and analysis results are described and compared to expected values indicated by other methods

1980-01-01

128

Human response times in a graphic environment  

CERN Multimedia

A summary of the results obtained from measuring the response times of the users of an interactive graphics system available on the CERN central computers is presented. These results are then used to find an optimum time to wait before rolling the user's program to disc.

Yule, A

1972-01-01

129

Measurement of decay times of fast scintillating fibers  

International Nuclear Information System (INIS)

A method is described for the determination of the decay times of scintillating fibers subjected to ionizing radiation. Excitation is by beta radiation from a custom-made 90Sr/90Y source. Pulse shapes are determined using time correlated single photon counting (TCPC) techniques.

1992-05-02

130

Measurement of decay times of fast scintillating fibers  

Energy Technology Data Exchange (ETDEWEB)

A method is described for the determination of the decay times of scintillating fibers subjected to ionizing radiation. Excitation is by beta radiation from a custom-made {sup 90}Sr/{sup 90}Y source. Pulse shapes are determined using time correlated single photon counting (TCPC) techniques.

Flournoy, J.M.

1992-01-01

131

Measurement of decay times of fast scintillating fibers  

International Nuclear Information System (INIS)

A method is described for the determination of the decay times of scintillating fibers subjected to ionizing radiation. Excitation is by beta radiation from a custom-made 90Sr/90Y source. Pulse shapes are determined using time correlated single photon counting (TCPC) techniques. (Author).

1992-05-02

132

Fast ?-ray coincidence timing using a BGO detector array in a nuclear reaction experiment  

International Nuclear Information System (INIS)

[en] The (7Li, 7Be) nuclear charge-exchange reaction has been investigated at E(7Li)=350 MeV. Coincidences were measured between the charged 7Be reaction products in the focal plane of a magnetic spectrometer and 430-keV Doppler-shifted ?-rays from the decay in flight of excited 7Be ejectiles. The latter were detected in a compact BGO detector array. Fast timing was used to optimize the separation between prompt and randoms events. The BGO output signals display the statistical distribution of the arrival times of individual photoelectrons from the photocathode in the photomultiplier tubes. A timing resolution of 6.5 ns relative to the accelerator RF was obtained. A simple model was successfully developed to simulate the BGO output signals with a statistical distribution of a predetermined number of photoelectrons modulated by the light output response of the scintillator and the single-photoelectron gain distribution and transit time through the photomultiplier tube. It is concluded that the timing resolution is primarily limited by the small number of photoelectrons. ((orig.))

1994-12-30

133

Automatic Synthesis of Fast, Compact Self-Timed Control  

UK PubMed Central (United Kingdom)

An automated synthesis tool, called the Most Excellent Asynchronous Tool, or MEAT is presented.This tool has been used to specify and synthesize self-timed circuits for a fully self-timed300,000 transistor communication co-processor. The specification is done with stylized state diagrams.This is a very compact and intuitive means to specify communication, concurrency,and synchronization necessary for control structures. Of primary importance to this projectwas the efficiency and simplicity of the implementation. The tool generates from the state descriptionprovably correct self-timed CMOS implementations with outstanding performance andcompactness.1 IntroductionThree major constraints -- speed of operation, size, and design time must be considered with anycomputer architecture, be it a commercial product or a laboratory prototype. As integrated circuittechnology improves, the amount of logic that can be placed on a VLSI circuit increases quadratically.Without impro...

Kenneth S. Stevens

134

Brief Communication: Greenland's shrinking ice cover: ?fast times? but not that fast  

Directory of Open Access Journals (Sweden)

Full Text Available A map of Greenland in the 13th edition (2011) of the Times Comprehensive Atlas of the World made headlines because the publisher's media release mistakenly stated that the permanent ice cover had shrunk 15 % since the previous 10th edition (1999) revision. The claimed shrinkage was immediately challenged by glaciologists, then retracted by the publisher. Here we show: (1) accurate maps of ice extent based on 1978/1987 aerial surveys and recent MODIS imaging; and (2) shrinkage at 0.019 % a?1 in ? 50 000 km2 of ice in a part of east Greenland that is shown as ice-free in the Times Atlas.

J. S. Kargel; A. P. Ahlstrøm; R. B. Alley; J. L. Bamber; T. J. Benham; J. E. Box; C. Chen; P. Christoffersen; M. Citterio; J. G. Cogley; H. Jiskoot; G. J. Leonard; P. Morin; T. Scambos; T. Sheldon; I. Willis

2011-01-01

135

Fast Time Variability in accreting Black Holes: 35 Years later  

Science.gov (United States)

Since the discovery of the aperiodic nature of the variability of Cygnus X-1 with Uhuru, we have accumulated a large wealth of information on black-hole binaries (BHB) with increasingly sensitive instruments. Only recently, a consistent pattern of behavior throughout the outburst of transient BHB has been identified, based both on spectral and timing characteristics. Yet, most of the aperiodic variability, in the form of Quasi-Periodic Oscillations but in particular of noise components, remains largely unexplained by theoretical models. I will concentrate on the most important features observed in the variability on short time scales and outline the similarities with what observed from neutron-star binaries, ULX and AGN. These represent the most direct information that we can obtain from the regions of space closest to a black hole. Once understood, they will allow not only to investigate the properties of accretion flows, but also to explore the space-time in the vicinity of black holes.

Belloni, Tomaso

136

Fast, real-time, DFT instrument based on VMEbus  

Science.gov (United States)

An emerging class of VMEbus-based test and measurement instruments is benchmarked by a recently introduced digital spectrum analyzer. The instrument performs real-time spectrum analysis in the DC-to-10 MHz range at 5000 spectrums per second. Its architecture is based on the VMEbus and is partly adapted for high-speed pipeline processing. The keyboard and color graphic displays suit basic spectrum analysis, as well as advanced analysis of amplitude vs. both frequency and time. The instrument provides a DSP (digital signal processing) programming environment when an RS232 terminal is attached. With addition of an RF spectrum analyzer, downconverter, and software, real-time analysis is extended to 21 GHz and beyond. Postprocessable spectral output makes the instrument suitable for use in a larger signal analysis or test system. This digital spectrum analyzer, which has 17 boards on the bus, is representative of an emerging class of filled-enclosure instruments.

Snell, Jay

137

Scheduling Strategy to Improve Response Time for Web Applications  

UK PubMed Central (United Kingdom)

We propose a tunable scheduling strategy that lies betweenFIFO and shortest-first, based on the value of a coefficient Alpha. IfAlpha is set to zero then this strategy is just FIFO. Larger Alpha getsus closer to shortest-first strategy which is known to provide optimalresponse time. However, unlike the shortest-first, proposed schedulingstrategy is starvation free. This scheduling strategy, called Alpha schedulingwith no preemption, allows to improve overall response time perHTTP request more than 3 times under heavy load. We demonstrateour results with a simple simulation model using SpecWeb96 to generaterepresentative WWW workload.1 IntroductionWith the growth of the World Wide Web, HTTP (Hyper Text Transfer Protocol[FGMFB97]) use has increased dramatically. It became the dominant methodto transfer the data over Wide Area Networks. Some web sites became extremallypopular and to function efficiently they needed fast, high-performance httpservers. There are ...

Ludmila Cherkasova

138

Fast changes for tough times: employee suggestion programs.  

UK PubMed Central (United Kingdom)

In the midst of the current marketplace's turmoil, healthcare organizations (HCOs) lack two critical commodities: time and money. Today, time and money are all that stand between many HCOs current operations and their demise at the hands of healthcare reform; therefore, healthcare administrators cannot afford to spend either frivolously. Consultants have put forth an array of employee incentive programs designed to address cost containment and market positioning goals of various institutions. Many of these programs are well packaged and can be considered "politically correct" in terms of current philosophies on employee-management relations. However, many programs focus on long-term goals and strategies and, therefore, are most appropriate for organizations not in immediate danger of demise. One long-term program espoused and implemented widely by organizations is the employee suggestion system. This article looks at employee suggestion programs.

Lyons DM

1997-06-01

139

Fast changes for tough times: employee suggestion programs.  

Science.gov (United States)

In the midst of the current marketplace's turmoil, healthcare organizations (HCOs) lack two critical commodities: time and money. Today, time and money are all that stand between many HCOs current operations and their demise at the hands of healthcare reform; therefore, healthcare administrators cannot afford to spend either frivolously. Consultants have put forth an array of employee incentive programs designed to address cost containment and market positioning goals of various institutions. Many of these programs are well packaged and can be considered "politically correct" in terms of current philosophies on employee-management relations. However, many programs focus on long-term goals and strategies and, therefore, are most appropriate for organizations not in immediate danger of demise. One long-term program espoused and implemented widely by organizations is the employee suggestion system. This article looks at employee suggestion programs. PMID:10168655

Lyons, D M

1997-06-01

140

Apparatus for Measuring Fast Doubling Times of the CABRI Reactor  

International Nuclear Information System (INIS)

The paper describes an apparatus for measuring doubling times as short as 1 ms in the CABRI reactor. The principal features of the apparatus are: - A period measurement range of from 1 ms to 10 s with an accuracy of better than 0.5%; - An ionization-chamber current measurement range of 3 x 10-7 to 10-5 A ; - Instant transmission of the results to a point 300 m distant from the reactor. The apparatus includes a constant sensitivity amplifier and several triggering circuits in parallel, the thresholds of which are set at fixed values of 0.3, 0.6, 1.2, 2.4, 4.8 and 9.6 V, and which define five doubling times. The output signals of the triggering circuits are serialized on a single wire, giving a train of six pulses, the intervals between which define the five doubling times. At the reception end a register distributes the stop-go commands of several scalers; there are five scalers of four decades each, counting clock pulses of 1 Mc/s frequency. The apparatus displays the results instantaneously on Nixie tubes and also provides for an automatic print-out on an IBM machine. The paper discusses the principles adopted for the design of the apparatus and lays particular stress on the theoretical accuracy of the measurements. (author)

1966-01-01

 
 
 
 
141

The response of some avalanche photodiodes to fast neutron irradiation  

Energy Technology Data Exchange (ETDEWEB)

Using the fast neutron flux available from the beam collector on the RAL spallation neutron source (ISIS) we have irradiated two types of avalanche photoiodes (APD) {l_brace}Hamamatsu S5345 (high capacitance) and the EG and G C30626E{r_brace} up to a maximum fluence of 2x10{sup 13} neutrons per cm{sup 2}. We report the behaviour of the device dark currents and noise characteristics through the course of the exposure to the neutron flux. (Author).

Bateman, J.E.; Stephenson, R.

1996-02-01

142

Dissociation of fast ions analyzed by time-of-flight  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The fragmentation of metastable ions, having keV of kinetic energy, is analyzed by time-of-flight technique. Assuming isotropic distribution of fragments in a free field region, it is deduced an analytical expression to describe the corresponding peak shapes in linear TOF spectrometers. Metastable ion mean-life and the kinetic energy release (Q-value) are the quantities extracted from data fitting. As an illustration, the dissociation of C8H10N+ metastable ions, desorbed by 252Cf ssion fragment impact on organic target, is studied.

Ponciano, C.R.; Ladeia, R.C.C.; Collado, V.M.; Silveira, E.F. da

2001-09-01

143

Dissociation of fast ions analyzed by time-of-flight  

Directory of Open Access Journals (Sweden)

Full Text Available The fragmentation of metastable ions, having keV of kinetic energy, is analyzed by time-of-flight technique. Assuming isotropic distribution of fragments in a free field region, it is deduced an analytical expression to describe the corresponding peak shapes in linear TOF spectrometers. Metastable ion mean-life and the kinetic energy release (Q-value) are the quantities extracted from data fitting. As an illustration, the dissociation of C8H10N+ metastable ions, desorbed by 252Cf ssion fragment impact on organic target, is studied.

Ponciano C.R.; Ladeia R.C.C.; Collado V.M.; Silveira E.F. da

2001-01-01

144

The development of a fast response thermocouple for use in liquid metals  

International Nuclear Information System (INIS)

Work carried out at Berkeley Nuclear Laboratories to develop a fast-response thermocouple for use in liquid metals is described. This thermocouple because of its unique construction, has a junction mass approaching zero and hence its frequency response should be very high. Some of the problems of manufacture are discussed, in particular the high quality of seal required to avoid ingress of liquid metal. A comparison of results obtained with the fast-response thermocouple and with conventional stainless-steel-sheathed thermocouples is made. The improved response of the new thermocouple is clearly visible, hence confirming that measurements made with sheathed thermocouples suffer attenuation. It is concluded that results obtained with the fast-response thermocouple are close to the real magnitude of temperature fluctuations present in turbulent flow. It is also demonstrated that, with suitable corrections, results obtained with sheathed thermocouples can be used to estimate the real signals present in the flow. (author)

1987-01-01

145

Fast and Flexible Modelling of Real-Time Systems with RTCP-Nets  

Directory of Open Access Journals (Sweden)

Full Text Available A large number of formalisms has been proposed for real-time systems modelling. However, formal methods are not widely used in industrial software development. Such a situation could be treated as a result of a lack of suitable tools for fast designing of a model, its analysis and modification. RTCP-nets have been defined to facilitate fast modelling of embedded systems incorporating rule-based systems. Computer tools that are being developed for RTCP-nets, use a template mechanism to allow users to design models and manipulate its properties fast and effectively. Both theoretical and practical aspects of RTCP-nets are presented in the paper.

Marcin Szpyrka

2004-01-01

146

Y2K issues for real time computer systems for fast breeder test reactor  

International Nuclear Information System (INIS)

Presentation shows the classification of real time systems related to operation, control and monitoring of the fast breeder test reactor. Software life cycle includes software requirement specification, software design description, coding, commissioning, operation and management. A software scheme in supervisory computer of fast breeder test rector is described with the twenty years of experience in design, development, installation, commissioning, operation and maintenance of computer based supervision control system for nuclear installation with a particular emphasis on solving the Y2K problem

1999-01-01

147

Mainlobe Jammer Nulling via TSI Finders: A Space Fast-Time Adaptive Processor  

Directory of Open Access Journals (Sweden)

Full Text Available An algorithm based on a space fast-time adaptive processor is presented for nulling the mainlobe jammer when the jammer and the target of interest share the same bearing. The computational load involved in the conventional processor, which blindly looks for the terrain-scattered interference (TSI), is required to stack a large number of consecutive range cell returns to form the space fast-time data snapshot making it almost impossible to implement in real time. This issue is resolved via the introduction of a preprocessor (a TSI finder which detects the presence of the minute levels of multipath components of the mainlobe jammer and associated time delays) which directs the STAP processor to select only two desired range returns in order to form the space fast-time data snapshot. The end result is a computationally extremely fast processor. Also a new space fast-time adaptive processor based on the super-resolution approach (eigenvector-based) is presented.

Madurasinghe Dan; Shaw Andrew P

2006-01-01

148

Test item response time and the response likelihood  

CERN Multimedia

Test takers do not give equally reliable responses. They take different responding strategies and they do not make the same effort to solve the problem and answer the question correctly. The consequences of differential test takers' behavior are numerous: the test item parameters could be biased, there might emerge differential item functioning for certain subgroups, estimation of test taker's ability might have greater error, etc. All the consequences are becoming more prominent at low-stakes tests where test takers' motivation is additionally decreased. We had analyzed a computer based test in Physics and tried to find and describe relationship between the item response time and the item response likelihood. We have found that magnitude of such relationship depends on the item difficulty parameter. We have also noticed that boys, who respond faster, in average, give responses with greater likelihood than the boys who respond slower. The same trend was not detected for girls.

Verbic, Srdjan

2009-01-01

149

Correlation time-of-flight spectrometer for fast neutrons  

International Nuclear Information System (INIS)

[en] A correlation time-of-flight spectrometer for measuring scattered neutron spectra with initial energy of 14 MeV is considered. The spectrometer contains a pulse neutron source, measuring instruments and a data storage system. The pulse neutron source is made on the basis of a cascade accelerator with the beam interruption system and deuteron targets. An ion beam modulation by a pseudo-casual signal is used in the spectrometer simultaneously with klystron grouping. This permits to preserve ion flux in the pulse and reduce the incoherent background effect on static accuracy. Ion pulses with an amplitude of 2 mmA and duration of 2.4 ns are obtained with the accelerator target. 2 scintillation detectors on the basis of stilbene and photo-electron multipliers are used as neutron detectors. The signal formation from the first detector is carried out by a discriminator with the neutron threshold of about 10 MeV, and from the second detector - by a discriminator with the threshold of 100 keV. The n-? compensation scheme is used in the second detector. The tests conducted show that integral and differential nonlinearity of the spectrometer equal 0.5 and +-1%, respectively

1977-04-22

150

Fast response key converter for power supply correction coil of the Tuman-3 device  

International Nuclear Information System (INIS)

A fast-response key thyristor converter with the maximum outlet voltage of 330-380 V at the current from 0 up to 2 kA and the limiting frequency of commutation of 1.2 kHz is developed to assure necessary control effects providing control of the plasma filament horizontal position in the ''Tuman-3'' TOKAMAK. During operation of the converter in an unipolar mode the plasma filament was stabilized in the horizontal direction with an accuracy of approximately 0.5 cm. Approximately 23 commutations with a minimum time between commutations of approximately 1.1 ms took place at the 25-30 ms interval of operation, i.e. plasma oscillations occurred in stabilization mode with maximum frequency up to 900 Hz

1982-01-01

151

Electrochromic device of PEDOT-PANI hybrid system for fast response and high optical contrast  

Energy Technology Data Exchange (ETDEWEB)

An organic-organic hybrid system composed of the polyaniline (PANI) and poly-(3,4-ethylenedioxythiophene) (PEDOT) with controlled thickness was developed successfully in order to realize synergetic effects in electrochromic (EC) properties such as optical contrast and color-switching rate. From the UV transmittance spectra, we found that the optical contrast ({delta}%T) was enhanced up to 6-72% at the wavelength of 580 nm compared with the previous PANI-PEDOT ECDs. Furthermore, the optimized ECD showed an extremely fast response time of less than 160 ms. It is therefore concluded that such a complementary full.cell system of PEDOT-PANI ECD is applicable as an optical device. (author)

Kang, Joo-Hee; Oh, Yeon-Ji; Hwang, Seong-Ju; Choy, Jin-Ho [Center for Intelligent Nano-Bio Materials (CINBM), Department of Chemistry and Nano Sciences, Ewha Womans University, Seoul 120-750 (Korea); Paek, Seung-Min [Center for Intelligent Nano-Bio Materials (CINBM), Department of Chemistry and Nano Sciences, Ewha Womans University, Seoul 120-750 (Korea); Beamline Research Division, Pohang Accelerator Laboratory, Pohang 790-784 (Korea)

2009-12-15

152

Combining Time Reversal and Fast Marching Method in Wireless Indoor Positioning  

Directory of Open Access Journals (Sweden)

Full Text Available Most of current wireless indoor positioning methods could not accurately obtain channel model, the mapping between spatial position and received signal features. The main factor for a precise channel model in an indoor environment is multipath effect. Time reversed (TR) wireless indoor positioning method has been validated to effectively reduce signals fading or time delay affected by multipath effect. However, these advantages are depended on a prior known channel model, without this condition, the accuracy of TR method will be seriously deteriorated. To solve the shortcoming of a general TR method in an unknown channel model application, we present a combining Time Reversal and Fast Marching Method (TR-FMM) positioning method. This method locates a target with two stages. In the stage one, the precise channel model of an indoor environment is estimated by FMM and simultaneous algebraic reconstruction technique (SART). In this stage, Time of Flight (TOF) information generated by some fixed spatial position anchors are used to fulfill the indoor channel model estimation, then the needed channel impulse response (CIR) for TR method will be obtained based on the estimated channel model. In the stage two, with the obtained CIR, any new joint mobile target will be accurately located by a general TR wireless indoor positioning method. Some numerical simulations have been presented to validate the proposed method. Simulative results depict the positioning deviation is less than 3cm for a newly joined mobile target with 1cm scale in a moderate complex indoor configure, and the accuracy of the positioning is improved 30 times comparing to a general TR method. The positioning time in the stage 2 is less than 3 minutes in a PC with 1.6 GHz dual CPUs and 2G Bytes memory. Obviously, the proposed method has great advantage in high accuracy and low complexity for wireless indoor positioning system.

Guoping Chen; Wenshan Wang; Hao Zeng; Chun Guan; Feng He

2013-01-01

153

Fast Retrieval of Time Series Using a Multi-resolution Filter with Multiple Reduced Spaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fast retrieval of time series that are similar to a given pattern in large databases is a problem which has received a lot of attention in the last decade. The high dimensionality and large size of time series databases make sequential scanning inefficient to handle the similarity search problem. Se...

Muhammad Fuad, Muhammad Marwan; Marteau, Pierre-François

154

Count-to-count time interval distribution analysis in a fast reactor  

International Nuclear Information System (INIS)

The most important kinetic parameters have been measured at the zero power fast reactor CORAL-I by means of the reactor noise analysis in the time domain, using measurements of the count-to-count time intervals. (Author) 69 refs.

1973-01-01

155

Effect of fasting versus feeding on the bone metabolic response to running.  

UK PubMed Central (United Kingdom)

Individuals often perform exercise in the fasted state, but the effects on bone metabolism are not currently known. We compared the effect of an overnight fast with feeding a mixed meal on the bone metabolic response to treadmill running. Ten, physically-active males aged 28 ± 4y (mean ±SD) completed two, counterbalanced, 8d trials. After 3d on a standardised diet, participants performed 60 min of treadmill running at 65% VO(2max) on Day 4 following an overnight fast (FAST) or a standardised breakfast (FED). Blood samples were collected at baseline, before and during exercise, for 3h after exercise, and on four consecutive follow-up days (FU1-FU4). Plasma/serum were analysed for the c-terminal telopeptide region of collagen type 1 (?-CTX), n-terminal propeptides of procollagen type 1 (P1NP), osteocalcin (OC), bone alkaline phosphatase (bone ALP), parathyroid hormone (PTH), albumin-adjusted calcium, phosphate, osteoprotegerin (OPG), cortisol, leptin and ghrelin. Only the ?-CTX response was significantly affected by feeding. Pre-exercise concentrations decreased more in FED compared with FAST (47% vs 26%, P<0.001) but increased during exercise in both groups and were not significantly different from baseline at 1h post-exercise. At 3h post-exercise, concentrations were decreased (33%, P<0.001) from baseline in FAST and significantly lower (P<0.001) than in FED. P1NP and PTH increased, and OC decreased during exercise. Bone markers were not significantly different from baseline on FU1-FU4. Fasting had only a minor effect on the bone metabolic response to subsequent acute, endurance exercise, reducing the duration of the increase in ?-CTX during early recovery, but having no effect on changes in bone formation markers. The reduced duration of the ?-CTX response with fasting was not fully explained by changes in PTH, OPG, leptin or ghrelin.

Scott JP; Sale C; Greeves JP; Casey A; Dutton J; Fraser WD

2012-12-01

156

Method and apparatus for measuring response time  

Energy Technology Data Exchange (ETDEWEB)

A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: applying a step input of predetermined value to the electrical instrument to generate an output signal; simultaneously starting a timer; comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and applying the stop signal when generated to stop the timer.

Johanson, E.W.; August, C.

1985-10-22

157

Method and apparatus for measuring response time  

Science.gov (United States)

A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, in which the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises: (1) applying a step input to predetermined value to the electrical instrument to generate an output signal; (2) simultaneously starting a timer; (3) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (4) applying the stop signal when generated to stop the timer.

Johanson, E. W.; August, C.

1983-08-01

158

Method and apparatus for measuring response time  

Energy Technology Data Exchange (ETDEWEB)

A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

Johanson, E.W.; August, C.

1983-08-11

159

Method and apparatus for measuring response time  

Energy Technology Data Exchange (ETDEWEB)

A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

Johanson, Edward W. (New Lenox, IL); August, Charles (Darien, IL)

1985-01-01

160

Does system response time disrupt working memory  

Energy Technology Data Exchange (ETDEWEB)

An experiment tested whether: (1) user performance decrements due to system response time (SRT) result from working memory disruption, and (2) SRT effects vary with task complexity. Subjects performed one- and three-step tasks resembling use of a screen editor while attempting to remember zero, three, or six digits. After each task step, SRT's of either zero, two, or six seconds were imposed. SRT increased task completion time, although more for the complex than for the simple task. There was neither a significant interaction between SRT and memory load, nor a main effect of memory load, showing that SRT does not disrupt working memory. 15 refs., 3 figs.

Schultz, E.E. Jr.; Uejio, J.Y.; De Alvare, A.M.

1988-01-01

 
 
 
 
161

Ultraviolet fast-response photoelectric effects in LiTaO{sub 3} single crystal  

Energy Technology Data Exchange (ETDEWEB)

The photoelectric effects of LiTaO{sub 3} (LTO) single crystals are experimentally studied with two kinds of LTO wafers, 10{sup 0} tilted and untilted, at room temperature. A transient open-circuit photoelectrical response of 143 ps rise time is observed in the 10{sup 0} tilted LTO when a 266 nm pulsed laser with a duration of 25 ps is irradiated directly onto the LTO surface. The untilted LTO with interdigitated electrodes of 10 {mu}m finger width and 10 {mu}m interspacing exhibits a linear dependence on the applied bias and power density of incident light, a response peak at about 235 nm and a sharp cutoff at about 270 nm. The noise current is only 61 pA at 20 V bias under the illumination of sunlight outdoors at midday. The experimental results suggest the promising application of the LTO single crystal in UV detection, in particular, as a solar-blind fast-response photodetector.

Guo Erjia; Xing Jie; Lu Huibin; Jin Kuijuan; Wen Juan; Yang Guozhen, E-mail: hblu@aphy.iphy.ac.c [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

2010-01-13

162

A continuous fast-response dual-tracer analyzer for halogenated atmospheric tracer studies  

Energy Technology Data Exchange (ETDEWEB)

An apparatus for the simultaneous measurement of two tracers, sulfur hexafluoride (SF6) and a perfluorocarbon compound, is introduced. The new instrument is a modification of a commercially available fast-response, continuous analyzer for single halogenated atmospheric tracer studies. A two-channel flow system was implemented consisting of an alumina cartridge in one channel and a glass beads cartridge of equal flow resistance in the second channel. The alumina passes only sulfur hexafluoride, while the glass beads pass both SF6 and the perfluoroarbon tracer. The SF6 is quantified directly from the electron capture detector (ECD) signal in the alumina channel, and the perfluorocarbon concentration is obtained from the difference of the ECD responses in the two channels. The dual-tracer analyzer is field portable for mobile operations or fixed-location monitoring, has a response time of 1.2 s, and has limits of detection of about 15 pptv for SF6 and 10 pptv for perfluoro-methylcyclohexane, which was the principal perfluorocarbon tracer used in this study. The present instrument configuration, which requires periodic purging of the adsorbent trap, can obtain continuous measurements for a 10-15-min segment in every half hour of operation. Dual-tracer data from a field demonstration test are presented.

Rydock, J.P.; Lamb, B.K. [Washington State Univ., Pullman, WA (United States)

1994-10-01

163

Fabrication and Characteristics of Fast Photo Response ZnO/Porous Silicon UV Photoconductive Detector  

Directory of Open Access Journals (Sweden)

Full Text Available Fast response time UV photoconductive detector was fabricated based on ZnO film prepared by thermal chemical spray pyrolysis technique. The ZnO nanofilms are grown on the porous silicon (PS) nanosurface which has drastically reduced the response time of the ZnO UV detector from few seconds to few hundreds of microseconds. The surface functionalization of the ZnO film deposited on porous silicon (PS) layer by polyamide nylon has highly improved the photoresponsivity of the detector to 0.8 A/W. The normalized de-tectivity (D*) of the fabricated ZnO UV detector at wavelength of 385 nm is found to be about 2.12 × 1011 cm Hz1/2 W–1. The ZnO film grown on the porous silicon layer was oriented in the c-axis and it is found to be a p-type semiconductor, which is referred to the compensation of the excess charge carriers in the ZnO film by the nanospikes silicon layer.

Hanan A. Thjeel; Abdulla. M. Suhail; Asama N. Naji; Qahtan G. Al-zaidi; Ghaida S. Muhammed; Faten A. Naum

2011-01-01

164

Fast X-ray micro-CT for real-time 4D observation  

Energy Technology Data Exchange (ETDEWEB)

Fast X-ray computed tomography (CT) system with sub-second order measurement for single CT acquisition has been developed. The system, consisting of a high-speed sample rotation stage and a high-speed X-ray camera, is constructed at synchrotron radiation beamline in order to utilize fully intense X-rays. A time-resolving CT movie (i.e. 4D CT) can be available by operating the fast CT system continuously. Real-time observation of water absorbing process of super-absorbent polymer (SAP) has been successfully performed with the 4D CT operation.

Takano, H; Yoshida, K; Tsuji, T; Koyama, T; Tsusaka, Y; Kagoshima, Y, E-mail: htakano@sci.u-hyogo.ac.j [Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297 (Japan)

2009-09-01

165

Fast photochromism in polymer matrix with plasticizer and real-time dynamic holographic properties  

Science.gov (United States)

We have developed a photochromic polymer film for the use of real-time dynamic hologram, fabricated by the plasticized polymer doped with the fast photochromic molecule. The addition of a plasticizer into the conventional polymer is proved to be effective to improve the photochromic performances for the polymer film doped with the fast photochromic molecule that shows instantaneous coloration upon exposure to UV light and rapid fading in the dark. The plasticized photochromic polymers enable the real-time control of the writing and erasing of a holographic grating and show a higher recording sensitivity compared with other organic holographic materials.

Ishii, Norihito; Abe, Jiro

2013-04-01

166

On Fast Chromospheric Responses to Microwave Subsecond Bursts  

Science.gov (United States)

We present a multi-wavelength analysis of chromosphere responses produced during the subsecond bursts detected by Siberian Solar Radio Telescope (SSRT, 5.7 GHz) on April 26, 2003 at 08:05:30 UT. The data obtained by Nobeyama Radioheliograph (NoRH, 17 and 34 GHz), Ondrejov observatory and RHESSI were also used. A correlation of multi-wavelength observations (microwave emission, hard X-rays and the video-cadence chromospheric line spectra from the Ondrejov observatory obtained with 0.04 second resolution) was performed to study fluxes on various levels of solar atmosphere before, during and after the event. The temporal resolution was high enough to resolve responses to subsecond pulses in the individual correlated fluxes and their possible interrelations. The results and possible scenario are briefly discussed from point of view of the energy transport mechanisms.

Kashapova, L. K.; Kotrc, P.; Meshalkina, N. S.

2008-09-01

167

High temperature fast response pressure probe for use in liquid metal droplet dispensers  

Science.gov (United States)

A miniature fast response high temperature pressure probe, with demonstrated use in liquid metals up to 255 °C (528 K), has been developed. Innovative packaging technologies have been applied to integrate a conventional piezoresistive silicon pressure sensor into the probe, without the need of an auxiliary water-cooling system. In situ static calibrations are used to verify the linearity of the pressure signal and the stability of the pressure sensitivity (0.5% standard deviation over 70 min at 255 °C). Dynamic calibration, completed in an air shock tube facility, yields the probe's natural frequency. This frequency, when corrected for probe operation in liquid tin, is found to be 100 kHz. The reliability and accuracy of the probe is assessed by mounting it in a tin droplet dispenser for use in an extreme ultraviolet light source. Droplet dispensers typically include an excitation mechanism, which can be based on the generation of acoustic pressure waves to impose a desired droplet frequency. The probe accuracy is verified by the comparison of pressure measurements with laser Doppler vibrometry measurements of the pressure generating structure. A reference pressure measurement, conducted at representative conditions, shows a complex frequency response, with peaks distributed over three orders of magnitude and maximum amplitude of 440 mbar. Time variance of the excitation mechanism due to thermal transients is studied by monitoring the pressure response during operation. Finally, the linearity of the excitation system, with respect to the excitation amplitude, is verified by response measurements. In conclusion, the developed probe is capable of characterizing the excitation mechanism of a liquid metal droplet dispenser. Additionally, real-time monitoring of the performance of the excitation system during long-term operation is possible.

Rollinger, B.; Mansour, M.; Abhari, R. S.

2012-06-01

168

Development and validation of a two-dimensional fast-response flood estimation model  

Energy Technology Data Exchange (ETDEWEB)

A finite difference formulation of the shallow water equations using an upwind differencing method was developed maintaining computational efficiency and accuracy such that it can be used as a fast-response flood estimation tool. The model was validated using both laboratory controlled experiments and an actual dam breach. Through the laboratory experiments, the model was shown to give good estimations of depth and velocity when compared to the measured data, as well as when compared to a more complex two-dimensional model. Additionally, the model was compared to high water mark data obtained from the failure of the Taum Sauk dam. The simulated inundation extent agreed well with the observed extent, with the most notable differences resulting from the inability to model sediment transport. The results of these validation studies complex two-dimensional model. Additionally, the model was compared to high water mark data obtained from the failure of the Taum Sauk dam. The simulated inundation extent agreed well with the observed extent, with the most notable differences resulting from the inability to model sediment transport. The results of these validation studies show that a relatively numerical scheme used to solve the complete shallow water equations can be used to accurately estimate flood inundation. Future work will focus on further reducing the computation time needed to provide flood inundation estimates for fast-response analyses. This will be accomplished through the efficient use of multi-core, multi-processor computers coupled with an efficient domain-tracking algorithm, as well as an understanding of the impacts of grid resolution on model results.

Judi, David R [Los Alamos National Laboratory; Mcpherson, Timothy N [Los Alamos National Laboratory; Burian, Steven J [UNIV OF UTAK

2009-01-01

169

A study on the response time characteristics related to shock control in the hydraulic system using the fluid device  

International Nuclear Information System (INIS)

Control of pressure transients in a hydraulic system may be important and necessary to avoid failures and to improve the efficiency of operation. Flow restricting devices can result in a decrease in the peak pressure, but may change the response time. The response time has an important effect on both operator and operator perceived smoothness. The response time should correspond to how fast a system responds to a given disturbance at the system boundary. Occasionally the appropriate response time is not easily determined. This study is on the response time characteristics in the hydraulic system studied for the control of response time

2001-01-01

170

Response of Gut Microbiota to Fasting and Hibernation in Syrian Hamsters? †  

Science.gov (United States)

Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4°C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class Clostridia predominated in both active and torpid hamsters and that populations of Akkermansia muciniphila, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters.

Sonoyama, Kei; Fujiwara, Reiko; Takemura, Naoki; Ogasawara, Toru; Watanabe, Jun; Ito, Hiroyuki; Morita, Tatsuya

2009-01-01

171

Response of gut microbiota to fasting and hibernation in Syrian hamsters.  

UK PubMed Central (United Kingdom)

Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4 degrees C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class Clostridia predominated in both active and torpid hamsters and that populations of Akkermansia muciniphila, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters.

Sonoyama K; Fujiwara R; Takemura N; Ogasawara T; Watanabe J; Ito H; Morita T

2009-10-01

172

Response of gut microbiota to fasting and hibernation in Syrian hamsters.  

Science.gov (United States)

Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4 degrees C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class Clostridia predominated in both active and torpid hamsters and that populations of Akkermansia muciniphila, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters. PMID:19700553

Sonoyama, Kei; Fujiwara, Reiko; Takemura, Naoki; Ogasawara, Toru; Watanabe, Jun; Ito, Hiroyuki; Morita, Tatsuya

2009-08-21

173

Observation of a fast evolution in a parity-time-symmetric system.  

UK PubMed Central (United Kingdom)

In parity-time-symmetric (PT-symmetric) Hamiltonian theory, the optimal evolution time can be reduced drastically and can even be zero. In this article, we report our experimental simulation of the fast evolution of a PT-symmetric Hamiltonian in a nuclear magnetic resonance quantum system. The experimental results demonstrate that the PT-symmetric Hamiltonian system can indeed evolve much faster than the quantum system, and the evolution time can be arbitrarily close to zero.

Zheng C; Hao L; Long GL

2013-04-01

174

Lesser time of preoperative fasting and early postoperative feeding are safe?  

UK PubMed Central (United Kingdom)

INTRODUCTION: Fasting in the night before elective surgery has been established to prevent pulmonary complications, vomiting, regurgitation and aspiration of gastric contents. The year of 2005 was developed the project ACERTO. It consists in a multidisciplinary team that aims to recover the surgical patient by administering two our six hours before surgery, a carbohydrate-rich beverage (12.5% dextrinomaltose). The multidisciplinary team consists of anesthesiologists, surgeons, nutritionists, nurses and physiotherapists. METHODS: Literature review of preoperative fasting conducted during September and October of 2011 in Scielo and PubMed. CONCLUSION: Reducing the time of preoperative fasting with high carbohydrate solution until two hours before the operation as early feeding postoperatively, bring numerous benefits to the patient. The ACERTO project has shown good results and these new behaviors should be encouraged, thereby reducing the recovery time of the surgical patient.

Ludwig RB; Paludo J; Fernandes D; Scherer F

2013-01-01

175

Seismic responses of a pool-type fast reactor with different core support designs  

International Nuclear Information System (INIS)

[en] In designing the core support system for a pool-type fast reactor, there are many issues which must be considered in order to achieve an optimum and balanced design. These issues include safety, reliability, as well as costs. Several design options are possible to support the reactor core. Different core support options yield different frequency ranges and responses. Seismic responses of a large pool-type fast reactor incorporated with different core support designs have been investigated. 4 refs., 3 figs

1989-01-01

176

Effect of short-term fasting on lipolytic responsiveness in normal and obese human subjects  

International Nuclear Information System (INIS)

In this study the rate of lipolysis (fatty acid and glycerol release into blood) has been quantified in both normal weight and obese volunteers after both 15 and 87 h of fasting. In each study, the basal rate and subsequent response to epinephrine infusion were determined. The rate of appearance (R/sub a/) of free fatty acids (FFA) and glycerol were quantified by infusion of [1-13C]palmitate and D-5-glycerol, respectively. Substrate flux rates per unit of body fat mass and lean body mass were calculated from total body water measurements using H218O dilution. In normal volunteers, the basal R/sub a/ FFA and R/sub a/ glycerol rose markedly with 87 h of fasting, whereas the increases were more modest in the obese subjects. However, the rate of mobilization of fat, in relation to the lean body mass, was higher in the obese subjects than in the normal subjects after 15 h of fasting, and the values were similar in both groups after 87 h of fasting. There was an increased lipolytic response to epinephrine after fasting in both groups. This increased sensitivity may have resulted from the enhancement of fatty acid-triglyceride substrate cycling that occurred after fasting

1987-01-01

177

Effect of short-term fasting on lipolytic responsiveness in normal and obese human subjects  

Energy Technology Data Exchange (ETDEWEB)

In this study the rate of lipolysis (fatty acid and glycerol release into blood) has been quantified in both normal weight and obese volunteers after both 15 and 87 h of fasting. In each study, the basal rate and subsequent response to epinephrine infusion were determined. The rate of appearance (R/sub a/) of free fatty acids (FFA) and glycerol were quantified by infusion of (1- TC)palmitate and D-5-glycerol, respectively. Substrate flux rates per unit of body fat mass and lean body mass were calculated from total body water measurements using H2 YO dilution. In normal volunteers, the basal R/sub a/ FFA and R/sub a/ glycerol rose markedly with 87 h of fasting, whereas the increases were more modest in the obese subjects. However, the rate of mobilization of fat, in relation to the lean body mass, was higher in the obese subjects than in the normal subjects after 15 h of fasting, and the values were similar in both groups after 87 h of fasting. There was an increased lipolytic response to epinephrine after fasting in both groups. This increased sensitivity may have resulted from the enhancement of fatty acid-triglyceride substrate cycling that occurred after fasting.

Wolfe, R.R.; Peters, E.J.; Klein, S.; Holland, O.B.; Rosenblatt, J.; Gary, H. Jr.

1987-02-01

178

Apomorphine-induced yawning in the rat: influence of fasting and time of day.  

UK PubMed Central (United Kingdom)

Yawning behavior is an experimental tool to study physiological responses, to elucidate the mechanisms of action of some drugs and hormones, and it is also a paradigm for some diseases and for dopamine (DA) agonists' clinical use. In this study, the effects of 24- and 48-h fasting as well as the influence of the light-dark cycle on apomorphine (APO)-induced yawning were evaluated. Initially, control and 48-h-fasted adult male rats were tested for yawning induced by APO (50, 100, 150 micrograms/kg, SC). The most effective dose tested was 100 micrograms/kg. Fasting significantly lowered yawning in all doses tested. Comparison between 24- and 48-h-fasted rats for APO (100 micrograms/kg)-induced yawning showed no significant difference between groups. Ad lib-fed groups were tested for APO (100 micrograms/kg)-induced yawning in both the light and in the dark phases of the cycle. Total number of yawnings increased significantly in the dark period. The present data show that fasting reduces and dark period increases APO-induced yawning in rats, suggesting that these conditions modulate the expression of this behavior.

Nasello AG; Tieppo CA; Felicio LF

1995-05-01

179

Apomorphine-induced yawning in the rat: influence of fasting and time of day.  

Science.gov (United States)

Yawning behavior is an experimental tool to study physiological responses, to elucidate the mechanisms of action of some drugs and hormones, and it is also a paradigm for some diseases and for dopamine (DA) agonists' clinical use. In this study, the effects of 24- and 48-h fasting as well as the influence of the light-dark cycle on apomorphine (APO)-induced yawning were evaluated. Initially, control and 48-h-fasted adult male rats were tested for yawning induced by APO (50, 100, 150 micrograms/kg, SC). The most effective dose tested was 100 micrograms/kg. Fasting significantly lowered yawning in all doses tested. Comparison between 24- and 48-h-fasted rats for APO (100 micrograms/kg)-induced yawning showed no significant difference between groups. Ad lib-fed groups were tested for APO (100 micrograms/kg)-induced yawning in both the light and in the dark phases of the cycle. Total number of yawnings increased significantly in the dark period. The present data show that fasting reduces and dark period increases APO-induced yawning in rats, suggesting that these conditions modulate the expression of this behavior. PMID:7610151

Nasello, A G; Tieppo, C A; Felicio, L F

1995-05-01

180

Comments on "Observation of Fast Evolution in Parity-Time-Symmetric System"  

CERN Document Server

In the paper "Observation of Fast Evolution in Parity-Time-Symmetric System" the authors propose a physical apparatus for the realization of a faster than Hermitian evolution. This last appears in contrast with the conclusions obtained in our paper "Some Remarks on Quantum Brachistochrone". We will clarify this apparent contradiction and some problematic aspects of the treatment in [1].

Masillo, Fabio

2011-01-01

 
 
 
 
181

Measurement of fast assembly spectra using time-of-flight method  

International Nuclear Information System (INIS)

Measurement of neutron spectra made in fast subcritical assemblies HUG 3 and PHUG 3 (uranium-graphite and plutonium-graphite) utilizing time-of-flight techniques are described. The matrix were excited by the pulsed neutron source from the BCMN Linac beam impinging on a target of natural uranium. Details of the experimental procedure, safety studies, detector calibration and data reduction are given.

1975-01-01

182

Hormonal responses to extreme fasting in subantarctic fur seal (Arctocephalus tropicalis) pups.  

UK PubMed Central (United Kingdom)

Surviving prolonged fasting implies closely regulated alterations in fuel provisioning to meet metabolic requirements, while preserving homeostasis. Little is known, however, of the endocrine regulations governing such metabolic adaptations in naturally fasting free-ranging animals. The hormonal responses to natural prolonged fasting and how they correlate to the metabolic adaptations observed, were investigated in subantarctic fur seal (Arctocephalus tropicalis) pups, which, because of the intermittent pattern of maternal attendance, repeatedly endure exceptionally long fasting episodes throughout their development (1-3 mo). Phase I fasting was characterized by a dramatic decrease in plasma insulin, glucagon, leptin, and total l-thyroxine (T(4)) associated with reductions in mass-specific resting metabolic rate (RMR), plasma triglycerides, glycerol, and urea-to-creatine ratio, while nonesterified fatty acids (NEFA) and ?-OHB increased. In contrast, the metabolic steady-state of phase II fasting reached within 6 days was associated with minimal concentrations of insulin, glucagon, and leptin; unchanged cortisol and triiodothyronine (T(3)); and moderately increased T(4). The early fall in insulin and leptin may mediate the shift to the strategy of energy conservation, protein sparing, and primary reliance on body lipids observed in response to the cessation of feeding. In contrast to the typical mammalian starvation response, nonelevated cortisol and minimal glucagon levels may contribute to body protein preservation and downregulation of catabolic pathways, in general. Furthermore, thyroid hormones may be involved in a process of energy conservation, independent of pups' nutritional state. These original hormonal settings might reflect an adaptation to the otariid repeated fasting pattern and emphasize the crucial importance of a tight physiological control over metabolism to survive extreme energetic constraints.

Verrier D; Atkinson S; Guinet C; Groscolas R; Arnould JP

2012-04-01

183

Flexible palladium-based h2 sensor with fast response and low leakage detection by nanoimprint lithography.  

UK PubMed Central (United Kingdom)

Flexible palladium-based H2 sensors have a great potential in advanced sensing applications, as they offer advantages such as light weight, space conservation, and mechanical durability. Despite these advantages, the paucity of such sensors is due to the fact that they are difficult to fabricate while maintaining excellent sensing performance. Here, we demonstrate, using direct nanoimprint lithography of palladium, the fabrication of a flexible, durable, and fast responsive H2 sensor that is capable of detecting H2 gas concentration as low as 50 ppm. High resolution and high throughput patterning of palladium gratings over a 2 cm × 1 cm area on a rigid substrate was achieved by heat-treating nanoimprinted palladium benzyl mercaptide at 250 °C for 1 h. The flexible and robust H2 sensing device was fabricated by subsequent transfer nanoimprinting of these gratings into a polycarbonate film at its glass transition temperature. This technique produces flexible H2 sensors with improved durability, sensitivity, and response time in comparison to palladium thin films. At ambient pressure and temperature, the device showed a fast response time of 18 s at a H2 concentration of 3500 ppm. At 50 ppm concentration, the response time was found to be 57 s. The flexibility of the sensor does not appear to compromise its performance.

Lim SH; Radha B; Chan JY; Saifullah MS; Kulkarni GU; Ho GW

2013-08-01

184

Flexible palladium-based h2 sensor with fast response and low leakage detection by nanoimprint lithography.  

Science.gov (United States)

Flexible palladium-based H2 sensors have a great potential in advanced sensing applications, as they offer advantages such as light weight, space conservation, and mechanical durability. Despite these advantages, the paucity of such sensors is due to the fact that they are difficult to fabricate while maintaining excellent sensing performance. Here, we demonstrate, using direct nanoimprint lithography of palladium, the fabrication of a flexible, durable, and fast responsive H2 sensor that is capable of detecting H2 gas concentration as low as 50 ppm. High resolution and high throughput patterning of palladium gratings over a 2 cm × 1 cm area on a rigid substrate was achieved by heat-treating nanoimprinted palladium benzyl mercaptide at 250 °C for 1 h. The flexible and robust H2 sensing device was fabricated by subsequent transfer nanoimprinting of these gratings into a polycarbonate film at its glass transition temperature. This technique produces flexible H2 sensors with improved durability, sensitivity, and response time in comparison to palladium thin films. At ambient pressure and temperature, the device showed a fast response time of 18 s at a H2 concentration of 3500 ppm. At 50 ppm concentration, the response time was found to be 57 s. The flexibility of the sensor does not appear to compromise its performance. PMID:23819468

Lim, Su Hui; Radha, Boya; Chan, Jie Yong; Saifullah, Mohammad S M; Kulkarni, Giridhar U; Ho, Ghim Wei

2013-07-12

185

Rigorous time domain responses of polarizable media  

Directory of Open Access Journals (Sweden)

Full Text Available The scope of this note is to study a model of induced polarization which fits the usually accepted frequency dependent formula of Cole and Cole, but is more general and allows the time domain observations to retrieve the parameters describing the induced polarization phenomena of the medium. By introducing the memory mechanisms, represented by derivatives of fractional order, in the relation between the electric flux density and the electric field and considering the fractional order differential equation which follows, I solve it with mathematically rigorous and closed formulae and compute the responses to a step function, a box, a set of positive boxes and a set of alternating positive and negative boxes. I also introduce a method which retrieves the parameters describing the medium when comparing the theoretical curves with the observed ones. The responses to these signals also allow to estimate the temporary alteration of the medium when repeated positive (negative) signals are input; the response increases (decreases) in amplitude when the signals are all positive (negative), it decreases when the signals are alternatively positive and negative in agreement with the known attitude of the medium to induced polarization.

M. Caputo

1997-01-01

186

Simple approach for fast real-time line scan microscopic imaging.  

UK PubMed Central (United Kingdom)

A simple fast line scan microscopic imaging approach based on a wavelength-space-time mapping technique has been proposed. With a lab-made subpicosecond pulse laser with 10 dB bandwidth of 12 nm, we experimentally demonstrate a free-space optical apparatus designed for fast line scan imaging of microscopic objects. This system has a spatial resolution of 22 ?m, field-of-view of 2.5 mm, and line scan rate of 20.9 MHz. By imaging a modified unitraveling carrier photodetector, we demonstrate the application of semiconductor device inspection for speeding up quality control.

Xing F; Chen H; Chen M; Yang S; Xie S

2013-10-01

187

TRANC – a novel fast-response converter to measure total reactive atmospheric nitrogen  

Directory of Open Access Journals (Sweden)

Full Text Available The input and loss of plant available nitrogen (N) from/to the atmosphere can be an important factor for the productivity of ecosystems and thus for its carbon and greenhouse gas exchange. We present a novel converter for the measurement of total reactive nitrogen (TRANC: Total Reactive Atmospheric Nitrogen Converter), which offers the opportunity to quantify the sum of all airborne reactive nitrogen (Nr) compounds in high time resolution. The basic concept of the TRANC is the full conversion of total Nr to nitrogen monoxide (NO) within two reaction steps. Initially, reduced N compounds are being oxidised, and oxidised N compounds are thermally converted to lower oxidation states. Particulate N is being sublimated and oxidised or reduced afterwards. In a second step, remaining higher N oxides or those originated in the first step are catalytically converted to NO with carbon monoxide used as reduction gas. The converter is combined with a fast response chemiluminescence detector (CLD) for NO analysis and its performance was tested for the most relevant gaseous and particulate Nr species under both laboratory and field conditions. Recovery rates during laboratory tests for NH3 and NO2 were found to be 95 and 99%, respectively, and 97% when the two gases were combined. In-field longterm stability over an 11-month period was approved by a value of 91% for NO2. Effective conversion was also found for ammonium and nitrate containing particles. The recovery rate of total ambient Nr was tested against the sum of individual measurements of NH3, HNO3, HONO, NH4+, NO3?, and NOx using a combination of different well-established devices. The results show that the TRANC-CLD system precisely captures fluctuations in Nr concentrations and also matches the sum of all Nr compounds measured by the different single techniques. The TRANC features a specific design with very short distance between the sample air inlet and the place where the thermal and catalytic conversions to NO occur. This assures a short residence time of the sample air inside the instrument, and minimises wall sorption problems of water soluble compounds. The fast response time (half-value periods of 0.30 s were found during concentration step changes) and high accuracy in capturing the dominant Nr species enables the converter to be used in an eddy covariance setup. Although a source attribution of specific Nr compounds is not possible, the TRANC is a new reliable tool for permanent measurements of the net Nr flux between ecosystem and atmosphere at a relatively low maintenance and reasonable cost level allowing for diurnal, seasonal and annual investigations.

O. Marx; C. Brümmer; C. Ammann; V. Wolff; A. Freibauer

2011-01-01

188

Ultra fast proton response of myoglobin upon ligand dissociation  

International Nuclear Information System (INIS)

In numerous biological processes, the ensuing protein structural changes accompanying a reaction at a specific site must spatially extend to mesoscopic dimensions to achieve a biological function. The molecular mechanism of cooperativity in oxygen binding of hemoglobin (Hb) is one of the classical problems in this aspect. The binding of small molecular ligands to the hemes in Hb is a highly localized perturbation. Nonetheless, this localized perturbation initiates a sequence of propagating structural events that culminates in a change of quaternary structure. The large-amplitude motions at the quaternary level, which form a communication link at the subunit interface, are driven by changes of the tertiary structure upon ligation. In this respect, myoglobin (Mb), which is structurally very similar to a subunit of Hb serves as a model system for the tertiary relaxation processes. Figure 1 demonstrates time-resolved UVRR difference spectra expanded the region of 650-1850 cm-1. The top and bottom traces correspond to the contracted probe-only spectrum and equilibrium deoxyMb minus MbCO difference spectrum, respectively. Tryptophan (Trp) and tyrosine (Tyr) bands appeared in the UVRR spectra are labeled by W and Y. In delay times between 5 and 300 ps, negative difference bands of W18, W16, and W3 modes showed little intensity change, on the other hand, negative difference band at 1620 cm-1 appreciably decreased in intensity. The intensity of W1 band with 226-nm excitation is less than one third of that of W3 band and the intensity of Trp bands other than W1 is invariant; hence, the intensity change of difference signal at 1620 cm-1 observed at 5 to 300 ps can be attributed to the intensity restoration of Y8a band. At 2.5 ns time delay, the transient difference spectrum does not coincide with the equilibrium difference spectrum. This means that the structural rearrangements toward the deoxy structure are not completed at 2.5 ns. Horse Mb has two Tyr residues: Tyr103 and Tyr146. X-ray crystallographic studies showed Tyr103 is exposed to the solvent in both deoxyMb and MbCO. Therefore, Tyr103 is not expected to show intensity changes upon CO dissociation. On the other hand, Tyr146 has a side chain which locates in the FG corner of Mb. It forms hydrogen bond to the backbone carbonyl of the proximal histidine (His93). Therefore, Tyr146 can be perturbed by the structural changes of the heme. We previously reported structural dynamics of Mb probed by visible resonance Raman spectroscopy. The data showed that the structural changes of the heme completes within 2 picoseconds and that there is structural relaxation around the heme with the time constant of 100 ps based on the frequency shift of iron-histidine stretching mode. The present data on the Tyr band are consistent with the previous data on heme and iron-histidine stretching band. Because Tyr146 forms hydrogen bond to the backbone carbonyl of the proximal histidine, spectral changes on both sites can be ascribed to the common protein motion in the heme vicinity of Mb. The Raman bands of Trp residues showed instantaneous intensity decrease and the intensity recovery in the nanosecond regime. In 100 ps region, there is no apparent intensity change for Trp bands in contrast to the change of Tyr Y8a band. Two Trp residues are involved in horse Mb: Trp7 and Trp14. Both residues are in the A helix and contact with the E helix. Although the A helix is far from the heme, intensity change of Trp bands occurs within 5 ps. It is hard to assume that the structural changes propagate from the heme group to the A helix in such a short time. More plausible idea is that upon CO dissociation the E helix moves and the movement perturbs the environments of Trp residues. Because the E helix locates just above the heme and can respond quickly to the dissociation. Time-resolved UVRR Measurements on Mb mutants, W7F and W14F, showed that Trp 14 contributes to the spectral changes in Figure 1 more than Trp7. Spectral changes in nanoseconds can be attributed to following motion of the A helix toward the h

2006-01-01

189

Ionization chamber with fast timing properties and good energy resolution for fission fragment detection  

International Nuclear Information System (INIS)

[en] A twin ionization chamber for fission fragment detection is described. The chamber allows to extract both, fast timing- and energy proportional signals. A time resolution of 1.62 ns FWHM was obtained between two fission fragments detected in the two halves of the chamber. For 241Am ?-particles the chamber gave an energy resolution of 1.3 percent. As counting gas methane NTP was used

1976-06-28

190

A fast rise time high voltage pulse generator for bounded-wave EMP simulator  

International Nuclear Information System (INIS)

A high voltage pulse generator with fast rise time is developed. The output wave of this generator is presented. The electromagnetic environment with 1.2 ns or 2.8 ns rise time and 50 ns pulse width can be produced when this generator is connected to bounded-wave EMP simulator which is used to investigate the EMP coupling effects of electrical equipment. (authors)

2006-01-01

191

Studies on fast timing and high precision tracking performance of Resistive Plate Chamber  

CERN Document Server

Resistive plate chambers (RPC), produced in large scales, are widely used as trigger detectors with O(ns) time resolution in high energy and high intensity experiments. To confront the future high experimental frontiers, such as the super-LHC, RPCs equipped with fine-pitch readout strips were tested with 180GeV/c muon at CERN SPS H8 beam line, to assess the viability of using RPCs for both fast timing and high precision tracking trigger.

Han, L; The ATLAS collaboration

2013-01-01

192

IRT Parameter Estimation with Response Times as Collateral Information  

Science.gov (United States)

Hierarchical modeling of responses and response times on test items facilitates the use of response times as collateral information in the estimation of the response parameters. In addition to the regular information in the response data, two sources of collateral information are identified: (a) the joint information in the responses and the…

van der Linden, Wim J.; Klein Entink, Rinke H.; Fox, Jean-Paul

2010-01-01

193

Development of a new time-amplitude converter with tunnel diodes for improving fast neutron spectrometry by time of flight  

International Nuclear Information System (INIS)

[en] New time-amplitude converter with Esaki diodes, the events being preselected before analysis, allows for realizing a fast neutron spectrometer by time-of-flight with an 1.5 * 10-9 s overall time resolution for 12C (n,n') at 14 MeV. (author)[fr] Realisation d'un convertisseur temps-amplitude a diodes 'tunnel', avec preselection des impulsions; l'application pour un spectrometre de neutrons rapides a temps-de-vol permet d'obtenir une resolution totale en temps de 1,5 nanoseconde dans la diffusion 12C (n,n') a 14 MeV. (auteur)

1963-01-01

194

Response Surface Methodology to Optimize Novel Fast Disintegrating Tablets Using ? Cyclodextrin as Diluent  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this work was to apply response surface approach to investigate main and interaction effects of formulation parameters in optimizing novel fast disintegrating tablet formulation using ? cyclodextrin as a diluent. The variables studied were diluent (? cyclodextrin, X1), superdisinteg...

Late, Sameer G.; Banga, Ajay K.

195

Design of a fast response ZrCo bed  

International Nuclear Information System (INIS)

For the ITER SDS bed, several ZrCo beds have been developed. Required performance of the ITER SDS bed is rapid recovery, rapid delivery of tritium and accurate measurement of the amount of in-bed tritium. From the ZrCo bed developed by T. Hayashi, 90% of hydrogen was supplied in 60 min at 350 .deg. C and the amount of tritium was measured at ±1% accuracy within 24 hours. M. Glugla reported that 90% of hydrogen was delivered in 17 min at 400 .deg. C, but 30% of the recovery and delivery capacity was lost after 10 times of a hydriding/dehydriding by disproportionation of ZrCo hydride at high temperature at 400 .deg. C. Based on the study of two existing ZrCo beds, a new ZrCo bed was designed and fabricated in order to increase the delivery rate and minimize the disproportionation rate. In this study, a more improved ZrCo bed design is presented.

2008-01-01

196

Sources of uncertainty in eddy covariance ozone flux measurements made by dry chemiluminescence fast response analysers  

Directory of Open Access Journals (Sweden)

Full Text Available We present a systematic intercomparison study of eddy covariance ozone flux measurements made using two fast response dry chemiluminescence analysers. Ozone deposition was measured over a well characterised managed grassland near Edinburgh, Scotland, during August 2007. A data quality control procedure specific to these analysers is introduced. Absolute ozone fluxes were calculated based on the relative signals of the dry chemiluminescence analysers using three different methods and the results are compared for both analysers. It is shown that the error in the fitted analyser calibration parameters required for the flux calculations provides a substantial source of uncertainty in the fluxes. The choice of the calculation method itself can also constitute an uncertainty in the flux as the calculated fluxes by the three methods do not agree within error at all times. This finding highlights the need for a consistent and rigorous approach for comparable datasets, such as e.g. in flux networks. Ozone fluxes calculated by one of the methods were then used to compare the two analysers in more detail. This systematic analyser comparison reveals half-hourly flux values differing by up to a factor of two at times with the difference in mean hourly flux ranging from 0 to 23% with an error in the mean daily flux of ± 12%. The comparison of analysers shows that the agreement in fluxes is excellent for some days but that there is an underlying uncertainty as a result of variable analyser performance and/or non-linear sensitivity.

J. B. A. Muller; C. J. Percival; M. W. Gallagher; D. Fowler; M. Coyle; E. Nemitz

2010-01-01

197

A real-time dynamic holographic material using a fast photochromic molecule  

Science.gov (United States)

We have developed a real-time, dynamic holographic material that exhibits rapid colouration upon irradiation with UV light and successive fast thermal bleaching within tens of milliseconds at room temperature. Photochromic polymer films were prepared by a simple solution-casting method from the benzene solution of the mixture of the photochromic molecule, poly(ethyl acrylate), and poly(phenoxyethyl acrylate). The real-time control of holographic images using the photochromic polymer film yields a speed equivalent to the time resolution of the human eye. This new type of dynamic holographic material based on fast photochromism opens up an exciting new area of research in the future development of a large dynamic 3D display.

Ishii, Norihito; Kato, Tetsuya; Abe, Jiro

2012-11-01

198

Real-time imaging of regional myocardial function using fast-SENC.  

UK PubMed Central (United Kingdom)

A technique for fast imaging of regional myocardial function using a spiral acquisition in combination with strain-encoded (SENC) magnetic resonance imaging (MRI) is presented in this paper. This technique, which is termed fast-SENC, enables scan durations as short as a single heartbeat. A reduced field of view (FOV) without foldover artifacts was achieved by localized SENC, which selectively excited the region around the heart. The two images required for SENC imaging (low- and high-tuning) were acquired in an interleaved fashion throughout the cardiac cycle to further shorten the scan time. Regional circumferential contraction and longitudinal shortening of both the left ventricle (LV) and right ventricle (RV) were examined in long- and short-axis views, respectively. The in vivo results obtained from five human subjects and five infarcted dogs are presented. The results of the fast-SENC technique in a single heartbeat acquisition were comparable to those obtained by conventional SENC in a long acquisition time. Therefore, fast-SENC may prove useful for imaging during stress or arrhythmia.

Pan L; Stuber M; Kraitchman DL; Fritzges DL; Gilson WD; Osman NF

2006-02-01

199

Fast modelling of the collimator-detector response in Monte Carlo simulation of SPECT imaging using the angular response function  

International Nuclear Information System (INIS)

Interactions of incident photons with the collimator and detector, including septal penetration, scatter and x-ray fluorescence, are significant sources of image degradation in applications of SPECT including dual isotope imaging and imaging using radioisotopes that emit high- or medium-energy photons. Modelling these interactions using full Monte Carlo (MC) simulations is computationally very demanding. We present a new method based on the use of angular response functions (ARFs). The ARF is a function of the incident photon's direction and energy and represents the probability that a photon will either interact with or pass through the collimator, and be detected at the intersection of the photon's direction vector and the detection plane in an energy window of interest. The ARFs were pre-computed using full MC simulations of point sources that include propagation through the collimator-detector system. We have implemented the ARF method for use in conjunction with the SimSET/PHG MC code to provide fast modelling of both interactions in the patient and in the collimator-detector system. Validation results in the three cases studied show that there was good agreement between the projections generated using the ARF method and those from previously validated full MC simulations, but with hundred to thousand fold reductions in simulation time.

2005-04-21

200

Time domain response of electrical ceramics -- Micro to megaseconds  

Energy Technology Data Exchange (ETDEWEB)

The electrical properties of ceramics can be measured in either the time domain or in the frequency domain. But for electrically nonlinear ceramics such as varistors, time-domain measurements provide insights that are different and more relevant to material performance as well as being more physically incisive. This article focuses specifically on the electrical properties of ZnO varistors, but much of it is of relevance for other materials, in particular those materials with grain-boundary barriers and disordered ceramics or glasses. The interpretation of electrical measurements in the time domain is profoundly influenced by such practical matters as source impedance and waveform characteristics. Experimental results are presented for both high and low source impedance relative to that of a test varistor, and the different in experimental difficulty and ease of interpretation is described. Time-domain measurements of capacitance and of the inductive response of varistors to large, fast electrical pulses are presented and their implications for varistor theory are given. Experimental evidence is given of short- and long-term memory in varistors. These memory phenomena are ascribed respectively to the life time of holes that become trapped in barriers and to polarization currents originating from deep electron traps. Polarization current measurements are presented for a wide range of time and temperature. The power-law time dependence and universal behavior of these currents is discussed. The exponent that describes the power law behavior is seen to change with temperature, and the change is interpreted as a double transition from diffusive to dispersive transport that originates with current from two different electron traps.

Modine, F.A. [Oak Ridge National Lab., TN (United States). Solid State Div.

1997-11-01

 
 
 
 
201

Using a fast-gated camera for measurements of transverse beam distributions and damping times  

International Nuclear Information System (INIS)

[en] With a fast-gated camera, synchrotron light was used for studying the transverse beam distributions and damping times in the Stanford Linear Collider (SLC) damping rings. By digitizing the image in the camera signal, the turn-by-turn time evolution of the transverse beam distribution was monitored and analyzed. The projections of the digitized image were fit with Gaussian functions to determine the moments of the distribution. Practical applications include the determination of injection matching parameters and the transverse damping times. In this report we describe a synchrotron light monitor and present experimental data obtained in the SLC damping rings

1992-01-01

202

Real-time, fast radio transient searches with GPU de-dispersion  

CERN Multimedia

The identification, and subsequent discovery, of fast radio transients through blind-search surveys requires a large amount of processing power, in worst cases scaling as $\\mathcal{O}(N^3)$. For this reason, survey data are generally processed offline, using high-performance computing architectures or hardware-based designs. In recent years, graphics processing units have been extensively used for numerical analysis and scientific simulations, especially after the introduction of new high-level application programming interfaces. Here we show how GPUs can be used for fast transient discovery in real-time. We present a solution to the problem of de-dispersion, providing performance comparisons with a typical computing machine and traditional pulsar processing software. We describe the architecture of a real-time, GPU-based transient search machine. In terms of performance, our GPU solution provides a speed-up factor of between 50 and 200, depending on the parameters of the search.

Magro, Alessio; Salvini, Stefano; Mort, Benjamin; Dulwich, Fred; Adami, Kristian Zarb

2011-01-01

203

Real-time, fast radio transient searches with GPU de-dispersion  

Science.gov (United States)

The identification and subsequent discovery of fast radio transients using blind-search surveys require a large amount of processing power, in worst cases scaling as ?. For this reason, survey data are generally processed off-line, using high-performance computing architectures or hardware-based designs. In recent years, graphics processing units (GPUs) have been extensively used for numerical analysis and scientific simulations, especially after the introduction of new high-level application programming interfaces. Here, we show how GPUs can be used for fast transient discovery in real time. We present a solution to the problem of de-dispersion, providing performance comparisons with a typical computing machine and traditional pulsar processing software. We describe the architecture of a real-time, GPU-based transient search machine. In terms of performance, our GPU solution provides a speed-up factor of between 50 and 200, depending on the parameters of the search.

Magro, A.; Karastergiou, A.; Salvini, S.; Mort, B.; Dulwich, F.; Zarb Adami, K.

2011-11-01

204

Development of a fast time-to-digital converter (TDC) using a programmable gate array  

International Nuclear Information System (INIS)

A fast time-to-digital converter with a 5 ns step was designed and tested by utilizing a user-programmable gate array. The stabilities against temperature and supply voltage variation were measured. A module was built with this TDC, and was successfully used in the first-level trigger system of the ZEUS detector to reject proton-beam induced background events. (author)

1994-01-01

205

A fast readout algorithm for Cluster Counting/Timing drift chambers on a FPGA board  

Science.gov (United States)

A fast readout algorithm for Cluster Counting and Timing purposes has been implemented and tested on a Virtex 6 core FPGA board. The algorithm analyses and stores data coming from a Helium based drift tube instrumented by 1 GSPS fADC and represents the outcome of balancing between cluster identification efficiency and high speed performance. The algorithm can be implemented in electronics boards serving multiple fADC channels as an online preprocessing stage for drift chamber signals.

Cappelli, L.; Creti, P.; Grancagnolo, F.; Pepino, A.; Tassielli, G.

2013-08-01

206

Advanced vapor recognition materials for selective and fast responsive surface acoustic wave sensors: a review.  

UK PubMed Central (United Kingdom)

The necessity of selectively detecting various organic vapors is primitive not only with respect to regular environmental and industrial hazard monitoring, but also in detecting explosives to combat terrorism and for defense applications. Today, the huge arsenal of micro-sensors has revolutionized the traditional methods of analysis by, e.g. replacing expensive laboratory equipment, and has made the remote screening of atmospheric threats possible. Surface acoustic wave (SAW) sensors - based on piezoelectric crystal resonators - are extremely sensitive to even very small perturbations in the external atmosphere, because the energy associated with the acoustic waves is confined to the crystal surface. Combined with suitably designed molecular recognition materials SAW devices could develop into highly selective and fast responsive miniaturized sensors, which are capable of continuously monitoring a specific organic gas, preferably in the sub-ppm regime. For this purpose, different types of recognition layers ranging from nanostructured metal oxides and carbons to pristine or molecularly imprinted polymers and self-assembled monolayers have been applied in the past decade. We present a critical review of the recent developments in nano- and micro-engineered synthetic recognition materials predominantly used for SAW-based organic vapor sensors. Besides highlighting their potential to realize real-time vapor sensing, their limitations and future perspectives are also discussed.

Afzal A; Iqbal N; Mujahid A; Schirhagl R

2013-07-01

207

Analysis of the ballistic impact response of a composite material using FAST Infrared Imagery  

Science.gov (United States)

The level of protection offered by a given ballistic material is typically evaluated in terms of a set of projectiles and their associated velocity at which a certain percentage of the projectiles are expected to perforate. (i.e. FSP 17gr : V50 = 500m/s, 9mm FMJ; V0=500m/s). These metrics give little information about the physical phenomena by which energy is dispersed, spread or absorbed in a specific target material. Aside from post-test inspection of the impacted material, additional information on the target response is traditionally obtained during a test from the use of high speed imaging, whether it is from a single camera aimed at the impact surface or the backface, or from a set of camera allowing full 3-D reconstruction of a deformed surface. Again, this kind of data may be difficult to interpret if the interest is in the way energy is managed in the target in real time. Recent technological progress in scientific grade high-speed infrared (IR) camera demonstrated that these phenomena can straightforwardly be measured using IR thermal imaging. This paper presents promising results obtained from Telops FAST-IR 1500 infrared camera on an aramid-based ballistic composite during an impact from a small caliber fragment simulating projectile (FSP).

Marcotte, Frederick; Ouellet, Simon; Farley, Vincent

2013-05-01

208

Influence of Time-Dependent Coupling Coefficients and Delay Times on the Kinetics of a Modular Fast Reactor Core  

International Nuclear Information System (INIS)

Previous treatments of kinetics problems in modular and toroidal cores in fast breeder reactors have been based on Avery's coupled kinetics equations for partial integral fission sources. Most of these calculations do not take account of the time dependence of the reactivity coupling coefficients caused by possible flux tilting in an excursion. Furthermore, the effect of time delays for neutrons travelling between the modules, which is expected to be small, is not included in the model itself. The present investigation of the behaviour of two coupled modules is based on our recent derivation of coupled reactor kinetics equations from the Boltzmann equation. The distribution functions of delay times for neutrons are approximated by delta functions. It is shown that in three-group theory an analytical expression for the average delay time between two modules can still be derived. The calculation is based on the three-group leakage fluxes. Cross-sections are condensed from a 26-group set. Step changes in fission cross-sections are considered as perturbations. Coupling coefficients are calculated using the critical flux distribution and, to show the effect of time dependence, using the asymptotic flux distribution. Finally, a numerical method for solving coupled reactor kinetics equations is outlined. Comparing solutions of simple kinetics problems without feed-back but with time-dependent coupling coefficients and delay times to solutions without consideration of these two effects, it is found that the influence of neutron delay times is indeed negligible for the usual transients considered in the safety analysis of fast breeder reactors. However, the inclusion of time-dependent coupling coefficients can markedly alter the module power during an excursion. (author)

1967-11-03

209

Fast nonlinear response in a GaAs photonic crystal waveguide in the picosecond regime  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We identify strong and fast refractive index changes that have a time constant of less than 10 ps, whilst studying the propagation of short pulses in GaAs photonic crystal (PC) waveguides on membrane. These measurements also illustrate the nonlinearities enhancement in PC structures and reveal the f...

Baron, Alexandre; Ryasnyanskiy, Aleksandr; Tran, Quynh Vy; Combrié, Sylvain; Dubreuil, Nicolas; Husko, C.; Delaye, Philippe

210

Slow-time-scale magnetic fields driven by fast-time-scale waves in an underdense relativistic Vlasov plasma  

International Nuclear Information System (INIS)

Slow-time-scale magnetic fields driven by fast-time-scale electromagnetic waves or plasma waves are examined from the perspective of the Vlasov-Maxwell equations for a relativistic Vlasov plasma. An equation for slow-time-scale magnetic field is obtained. The field proposed in the present paper is a result of wave-wave beating which drives a solenoidal current. The magnitude of the slow-time-scale magnetic field proposed here can be as high as 20 MG at the critical surface for a laser intensity I=1018 W/cm2 at wavelength ?0=1.05 ?m. The predicted magnetic field is observed in two-dimensional particle simulations presented here.

2001-01-01

211

Response of six neutron survey meters in mixed fields of fast and thermal neutrons.  

UK PubMed Central (United Kingdom)

Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ?9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ?85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ?50 % in the thermal neutron field.

Kim SI; Kim BH; Chang I; Lee JI; Kim JL; Pradhan AS

2013-01-01

212

Euler equations on a fast rotating sphere --- time-averages and zonal flows  

CERN Multimedia

Motivated by recent studies in geophysical and planetary sciences, we investigate the PDE-analytical aspects of time-averages for barotropic, inviscid flows on a fast rotating sphere $S^2$. Of particular interests are the incompressible Euler equations. We prove that the finite-time-average of the solution stays close to a subspace of \\emph{longitude-independent zonal flows}. The intial data can be arbitrarily far away from this subspace. Meridional variation of the Coriolis parameter underlies this phenomenon. Our proofs use Riemannian geometric tools, in particular the Hodge Theory.

Cheng, Bin

2011-01-01

213

Fast Chebyshev-polynomial method for simulating the time evolution of linear dynamical systems.  

Science.gov (United States)

We present a fast method for simulating the time evolution of any linear dynamical system possessing eigenmodes. This method does not require an explicit calculation of the eigenvectors and eigenfrequencies, and is based on a Chebyshev polynomial expansion of the formal operator matrix solution in the eigenfrequency domain. It does not suffer from the limitations of ordinary time-integration methods, and can be made accurate to almost machine precision. Among its possible applications are harmonic classical mechanical systems, quantum diffusion, and stochastic transport theory. An example of its use is given for the problem of vibrational wave-packet propagation in a disordered lattice. PMID:11415044

Loh, Y L; Taraskin, S N; Elliott, S R

2001-04-26

214

Fast Chebyshev-polynomial method for simulating the time evolution of linear dynamical systems.  

UK PubMed Central (United Kingdom)

We present a fast method for simulating the time evolution of any linear dynamical system possessing eigenmodes. This method does not require an explicit calculation of the eigenvectors and eigenfrequencies, and is based on a Chebyshev polynomial expansion of the formal operator matrix solution in the eigenfrequency domain. It does not suffer from the limitations of ordinary time-integration methods, and can be made accurate to almost machine precision. Among its possible applications are harmonic classical mechanical systems, quantum diffusion, and stochastic transport theory. An example of its use is given for the problem of vibrational wave-packet propagation in a disordered lattice.

Loh YL; Taraskin SN; Elliott SR

2001-05-01

215

Time Series Technical Analysis via new Fast Estimation Methods: A Preliminary Study in Mathematical Finance  

CERN Multimedia

New fast estimation methods stemming from control theory lead to a fresh look at time series, which bears some resemblance to "technical analysis". The results are applied to a typical object of financial engineering, namely the forecast of foreign exchange rates, via a "model-free" setting, i.e., via repeated identifications of low order linear difference equations on sliding short time windows. Several convincing computer simulations, including the prediction of the position and of the volatility with respect to the forecasted trendline, are provided. $\\mathcal{Z}$-transform and differential algebra are the main mathematical tools.

Fliess, Michel

2008-01-01

216

Application of Time Projection Chambers with GEMs and Pixels to WIMP Searches and Fast Neutron Detection  

CERN Multimedia

We present work on the detection of neutral particles via nuclear recoils in gas-filled Time Projection Chambers (TPCs). We employ Gas Electron Multipliers (GEMs) to amplify the signal and silicon pixel electronics to detect the avalanche charge. These technologies allow ionization in the target gas to be detected with low noise, improved position and time resolution, and high efficiency. We review experimental results obtained in previous years, and report on ongoing simulation studies and construction of the first prototype at the University of Hawaii. We also present prospects of using such detectors to perform direction-sensitive searches for WIMP dark matter and fast neutron from fissionable material.

Yamaoka, Jared; Garcia-Sciveres, Maurice; Jaegle, Igal; Kadyk, John; Nguyen, Young; Rosen, Marc; Ross, Steven; Thorpe, Thomas; Vahsen, Sven

2012-01-01

217

New fast-neutron time-of-flight facilities at CYRIC  

CERN Multimedia

An outline of the new fast-neutron time-of-flight facilities equipped with the K=110 MeV AVF cyclotron at Cyclotron and Radioisotope Center is described. Results of the performance test for analyzing neutrons from the sup 6 Li(p,n) sup 6 Be reaction at E sub p =70 MeV show that the total system of facilities works reasonably well and present good place for extended nuclear spectroscopic studies, together with the newly installed AVF cyclotron which provides high-time resolution beams in the order of several hundred pico-seconds.

Terakawa, A; Kumagai, K; Kikuchi, Y; Uekusa, T; Uemori, T; Fujisawa, H; Sugimoto, N; Itoh, K; Baba, M; Orihara, H; Maeda, K

2002-01-01

218

3-D seismic response of a base-isolated fast reactor  

International Nuclear Information System (INIS)

[en] This paper describes a 3-D response analysis methodology development and its application to a base-isolated fast breeder reactor (FBR) plant. At first, studies on application of a base-isolation system to an FBR plant were performed to identify a range of appropriate characteristics of the system. A response analysis method was developed based on mathematical models for the restoring force characteristics of several types of the systems. A series of shaking table tests using a small scale model was carried out to verify the analysis method. A good agreement was seen between the test and analysis results in terms of the horizontal and vertical responses. Parametric studies were then made to assess the effects of various factors which might be influential to the seismic response of the system. Moreover, the method was applied to evaluate three-dimensional response of the base-isolated FBR. (author)

1992-01-01

219

Fast time-resolved imaging of diffusely scattering solid phantoms for optical mammography  

Science.gov (United States)

We have performed time-resolved imaging of diffusely scattering solid phantoms containing an optical inhomogeneity with increased absorption or scattering to simulate a human breast with a tumor inside. Images based on time-domain quantities derived from measured distributions of times of flight of photons are compared to those based on Fourier components. Investigations of contrast and signal- to-noise ratio of transillumination images recorded at different exposure times, i.e. at different numbers of photons detected, show that full images of the phantoms can be obtained within a few minutes only. In addition, we demonstrate that low power picosecond semiconductor lasers are suited for fast time-resolved imaging.

Grosenick, Dirk; Danlewski, Harald; Rinneberg, Herbert H.

1996-12-01

220

Hierarchical IDEAL: fast, robust, and multiresolution separation of multiple chemical species from multiple echo times.  

UK PubMed Central (United Kingdom)

We describe a generalized version of hierarchical IDEAL that can flexibly handle arbitrary chemical species at arbitrary echo times. The proposed work is fast and robust, and it has three key features: (1) multiresolution approach, which allows the method to handle images with disjoint regions, makes it less susceptible to local optima, and reduces the ambiguity of the separation; (2) direct phase estimation, which bypasses the phase wrapping issue, and (3) efficient algebraic formulation, which enables fast calculation and insensitivity to spatially varying phase across the image, from sources such as partial echo acquisition, receiver coils, motion, and flow. Representative results at 1.5 T and 3 T are presented from human ankle, wrist, and a water/oil/silicone phantom.

Tsao J; Jiang Y

2013-07-01

 
 
 
 
221

Lifetime, turnover time, and fast magnetic field regeneration in random flows  

International Nuclear Information System (INIS)

The fast dynamo is thought to be relevant in the regeneration of magnetic fields in astrophysics where the value of the magnetic Reynolds number (Rm) is immense. The fast dynamo picture is one in which chaotic flows provide a mechanism for the stretching of magnetic field lines. Furthermore, a cascade of energy down to small scales results in intermittent regions of a small-scale, intense magnetic field. Given this scenario it is natural to invoke the use of kinematic random flows in order to understand field regeneration mechanisms better. Here a family of random flows is used to study the effects that L, the lifetime of the cell, and ?, the turnover time of the cell, may have on magnetic field regeneration. Defining the parameter ?=L/?, it has been varied according to ?>1, ?

2007-01-01

222

INFLUENCE OF RAMADAN FASTING ON ANAEROBIC PERFORMANCE AND RECOVERY FOLLOWING SHORT TIME HIGH INTENSITY EXERCISE  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 ± 1.25 yr) participated in this study. The subjects were tested three times [3 days before the beginning of Ramadan (Pre-RF), the last 3 days of Ramadan (End-RF) and the last 3 days of the 4th week after the end of Ramadan (After-RF)]. Anaerobic power and capacity were measured by using the Wingate Anaerobic Test (WAnT) at Pre-RF, End-RF and After- RF. Capillary blood samples for lactate analyses and heart rate recordings were taken at rest, immediately after WAnT and throughout the recovery period. Repeated measures of ANOVA indicated that there were no significant changes in body weight, body mass index, fat free mass, percentage of body fat, daily sleeping time and daily caloric intake associated with Ramadan fasting. No significant changes were found in total body water either, but urinary density measured at End-RF was significantly higher than After-RF. Similarity among peak HR and peak LA values at Pre-RF, End- RF and After-RF demonstrated that cardiovascular and metabolic stress caused by WAnT was not affected by Ramadan fasting. In addition, no influence of Ramadan fasting on anaerobic power and capacity and removal rate of LA from blood following high intensity exercise was observed. The results of this study revealed that if strength-power training is performed regularly and daily food intake, body fluid balance and daily sleeping time are maintained as before Ramadan, Ramadan fasting will not have adverse effects on body composition, anaerobic power and capacity, and LA metabolism during and after high intensity exercise in power athletes

Umid Karli; Alpay Guvenc; Alper Aslan; Tahir Hazir; Caner Acikada

2007-01-01

223

Evaluation of nonlinear structural dynamic responses using a fast-running spring-mass formulation  

Science.gov (United States)

In today's world, accurate finite-element simulations of large nonlinear systems may require meshes composed of hundreds of thousands of degrees of freedom. Even with today's fast computers and the promise of ever-faster ones in the future, central processing unit (CPU) expenditures for such problems could be measured in days. Many contemporary engineering problems, such as those found in risk assessment, probabilistic structural analysis, and structural design optimization, cannot tolerate the cost or turnaround time for such CPU-intensive analyses, because these applications require a large number of cases to be run with different inputs. For many risk assessment applications, analysts would prefer running times to be measurable in minutes. There is therefore a need for approximation methods which can solve such problems far more efficiently than the very detailed methods and yet maintain an acceptable degree of accuracy. For this purpose, we have been working on two methods of approximation: neural networks and spring-mass models. This paper presents our work and results to date for spring-mass modeling and analysis, since we are further along in this area than in the neural network formulation. It describes the physical and numerical models contained in a code we developed called STRESS, which stands for 'Spring-mass Transient Response Evaluation for structural Systems'. The paper also presents results for a demonstration problem, and compares these with results obtained for the same problem using PRONTO3D, a state-of-the-art finite element code which was also developed at Sandia.

Benjamin, A. S.; Altman, B. S.; Gruda, J. D.

224

Evaluation of nonlinear structural dynamic responses using a fast-running spring-mass formulation  

Energy Technology Data Exchange (ETDEWEB)

In today`s world, accurate finite-element simulations of large nonlinear systems may require meshes composed of hundreds of thousands of degrees of freedom. Even with today`s fast computers and the promise of ever-faster ones in the future, central processing unit (CPU) expenditures for such problems could be measured in days. Many contemporary engineering problems, such as those found in risk assessment, probabilistic structural analysis, and structural design optimization, cannot tolerate the cost or turnaround time for such CPU-intensive analyses, because these applications require a large number of cases to be run with different inputs. For many risk assessment applications, analysts would prefer running times to be measurable in minutes. There is therefore a need for approximation methods which can solve such problems far more efficiently than the very detailed methods and yet maintain an acceptable degree of accuracy. For this purpose, we have been working on two methods of approximation: neural networks and spring-mass models. This paper presents our work and results to date for spring-mass modeling and analysis, since we are further along in this area than in the neural network formulation. It describes the physical and numerical models contained in a code we developed called STRESS, which stands for ``Spring-mass Transient Response Evaluation for structural Systems``. The paper also presents results for a demonstration problem, and compares these with results obtained for the same problem using PRONTO3D, a state-of-the-art finite element code which was also developed at Sandia.

Benjamin, A.S.; Altman, B.S.; Gruda, J.D.

1995-03-01

225

The genetic architecture of fasting plasma triglyceride response to fenofibrate treatment.  

Science.gov (United States)

Metabolic response to the triglyceride (TG)-lowering drug, fenofibrate, is shaped by interactions between genetic and environmental factors, yet knowledge regarding the genetic determinants of this response is primarily limited to single-gene effects. Since very low-density lipoprotein (VLDL) is the central carrier of fasting TG, identifying factors that affect both total TG and VLDL-TG response to fenofibrate is critical for predicting individual fenofibrate response. As part of the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study, 688 individuals from 161 families were genotyped for 91 single-nucleotide polymorphisms (SNPs) in 25 genes known to be involved in lipoprotein metabolism. Using generalized estimating equations to control for family structure, we performed linear modeling to investigate whether single SNPs, single covariates, SNP-SNP interactions, and/or SNP-covariate interactions had a significant association with the change in total fasting TG and fasting VLDL-TG after 3 weeks of fenofibrate treatment. A 10-iteration fourfold cross-validation procedure was used to validate significant associations and quantify their predictive abilities. More than one-third of the significant, cross-validated SNP-SNP interactions predicting each outcome involved just five SNPs, showing that these SNPs are of key importance to fenofibrate response. Multiple variable models constructed using the top-ranked SNP--covariate interactions explained 11.9% more variation in the change in TG and 7.8% more variation in the change in VLDL than baseline TG alone. These results yield insight into the complex biology of fenofibrate response, which can be used to target fenofibrate therapy to individuals who are most likely to benefit from the drug. PMID:18212815

Smith, Jennifer A; Arnett, Donna K; Kelly, Reagan J; Ordovas, Jose M; Sun, Yan V; Hopkins, Paul N; Hixson, James E; Straka, Robert J; Peacock, James M; Kardia, Sharon L R

2008-01-23

226

Fast neutron response of LiF T.L. dosimeters  

International Nuclear Information System (INIS)

[en] Generally, the intensity of the main dosimetric peak i.e. the sensitivity of the most thermoluminescence (T.L.) dosimeters (expressed as the T.L. response/absorbed dose) decreases with increasing Let. However, it is known that the 'high temperature peak' (H.T.P.) of LiF:Mg,Ti T.L. detectors increases with increasing Let, while the 'low temperature peak' (L.T.P.) of LiF:Mg,Ti decreases. H.T.P., also called peak 7, appears between 240- 270 Celsius degrees, while L.T.P. can be found in the literature as peak 5 or 'dosimetric' peak and appears in the temperature range 180 -240 Celsius degrees. The dose response results of L.T.P. and H.T.P. of LiF:Mg,Ti in the literature are ambiguous in high Let radiation field. The reason in most cases is that the gamma component in the mixed field is not taken properly into consideration. In the every day practice work place monitoring it is necessary to measure low Let (gamma) and both low and high Let (e.g. gamma-neutron) radiation in the mixed fields. T.L.D. -100 (Harshaw) and M.T.S.-N (Poland) LiF:Mg,Ti dosimeters produced from natural LiF are easily available and widely used in the practical dosimetry tasks. The aim of this study was to compare the Let sensitivity of L.T.P. and H.T.P. for T.L.D.-100 (Harshaw) and M.T.S.-N (Poland) LiF detectors for 14.5 MeV neutrons in the dose range 50 mGy-300 mGy (expressed in tissue kerma). At the same time the effect of the holder type to the dosimeter response was also studied. 14.5 MeV fast neutrons produced by Texas Nuclear Corporation 300 keV electrostatic accelerator using 3 H(d,n)4 He nuclear reaction was used for neutron irradiation. The gamma component in the mixed field was measured by Geiger-Mueller counter calibrated in standard dosimetry laboratory. Gamma irradiation was carried out by 137Cs source. It was found, that while the gamma sensitivity of M.T.S. -N compared to T.L.D.-100 is about 2.5, the fast neutron sensitivity is much lower,equal to about 0.7. The responses of the low and high temperature T.L. peaks are linear for both kinds of LiF detectors in the dose range investigated. Adequate analytical peak separation and curve fitting programme enabled estimation of the relative neutron sensitivity of both peaks and the assessment of changes on the structure of glow curves by changes of Let of radiation. With respect to different sensitivities of H.T.P. and L.T.P. both M.T.S. -N and T.L.D.-100 are suitable for simultaneous measurement of neutron and gamma component of the dose in a mixed neutron-gamma radiation field using single dosimeter. (authors)

2006-01-01

227

A new type of hybrid code for fast-electron transport with hydrodynamic response  

Science.gov (United States)

We present a new hybrid code, relevant to fast-ignition, with PIC fast-electrons coupled to a Vlasov-Fokker-Planck (VFP) background plasma. Using the VFP code IMPACT [1] for the plasma provides a more complete Ohm's law & heat-flow description than fluid models, conventionally used. Transport in the plasma includes magnetization effects & non-local effects when the background is driven hard by the beam. Phenomena such as Nernst advection of B-fields, resistive & ?nx?T B-field generation are included. The code also includes ionization. As it is a hybrid code, several picosecond timescales are easily achievable. This makes the code well suited to study the effects of hydrodynamics on fast-electron transport [2], such as re-collimation of the beam due to PdV cooling in the background plasma [3]. The code has been tested against relevant beam-plasma instabilities and is being used to study systems with parameters relevant to FI. We present new results of fast-electrons travelling though a solid density background with hydrodynamic response. [4pt] [1] Kingham RJ & Bell AR, JCP 194, 1(2004)[0pt] [2] Bush IA et al., PPCF 52 125007 (2010)[0pt] [3] Kingham RJ et al., J. Phys.: Conf. Ser. 244 022042 (2010)

Kingham, Robert; Williams, Brennig

2011-11-01

228

Event synchronization a simple and fast method to measure synchronicity and time delay patterns  

CERN Multimedia

We propose a simple method to measure synchronization and time delay patterns between signals. It is based on the relative timings of events in the time series, defined e.g. as local maxima. The degree of synchronization is obtained from the number of quasi-simultaneous appearances of events, and the delay is calculated from the precedence of events in one signal with respect to the other. Moreover, we can easily visualize the time evolution of the delay and synchronization level with an excellent resolution. We apply the algorithm to short rat EEG signals, some of them containing spikes. We also apply it to an intracranial human EEG recording containing an epileptic seizure, and we propose that the method might be useful for the detection of foci and for seizure prediction. It can be easily extended to other types of data and it is very simple and fast, thus being suitable for on-line implementations.

Quiroga, R Q; Grassberger, Peter

2002-01-01

229

Hormonal responses to a fast-food meal compared with nutritionally comparable meals of different composition.  

UK PubMed Central (United Kingdom)

BACKGROUND: Fast food is consumed in large quantities each day. Whether there are differences in the acute metabolic response to these meals as compared to 'healthy' meals with similar composition is unknown. DESIGN: Three-way crossover. METHODS: Six overweight men were given a standard breakfast at 8:00 a.m. on each of 3 occasions, followed by 1 of 3 lunches at noon. The 3 lunches included: (1) a fast-food meal consisting of a burger, French fries and root beer sweetened with high fructose corn syrup; (2) an organic beef meal prepared with organic foods and a root beer containing sucrose, and (3) a turkey meal consisting of a turkey sandwich and granola made with organic foods and an organic orange juice. Glucose, insulin, free fatty acids, ghrelin, leptin, triglycerides, LDL-cholesterol and HDL-cholesterol were measured at 30-min intervals over 6 h. Salivary cortisol was measured after lunch. RESULTS: Total fat, protein and energy content were similar in the 3 meals, but the fatty acid content differed. The fast-food meal had more myristic (C14:0), palmitic (C16:0), stearic (C18:0) and trans fatty acids (C18:1) than the other 2 meals. The pattern of nutrient and hormonal response was similar for a given subject to each of the 3 meals. The only statistically significant acute difference observed was a decrease in the AUC of LDL cholesterol after the organic beef meal relative to that for the other two meals. Other metabolic responses were not different. CONCLUSION: LDL-cholesterol decreased more with the organic beef meal which had lesser amounts of saturated and trans fatty acids than in the fast-food beef meal.

Bray GA; Most M; Rood J; Redmann S; Smith SR

2007-01-01

230

Effect of time of day and fasting duration on measures of glycaemia: analysis from the Whitehall II Study.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We aimed to study diurnal variation in glucose regulation by examining the effects of time of day and fasting duration on fasting plasma glucose (FPG), 2 h post-load plasma glucose (2hPG) and HbA(1c) levels.

Hulmán, A; Færch, K; Vistisen, D; Karsai, J; Nyári, TA; Tabák, AG; Brunner, EJ; Kivimäki, M; Witte, DR

231

MOS hydrogen sensor with very fast response based on ultra-thin thermal SiO{sub 2} film  

Energy Technology Data Exchange (ETDEWEB)

An MOS capacitor-type hydrogen gas sensor was fabricated with the structure of Ni/SiO{sub 2}/Si by using conventional silicon wafer technologies. Grown by dry oxidation at 900 C, the thickness of the SiO{sub 2} film was only 24A. At 150 C, comparing to another MOS capacitor with 148A-thick oxide and otherwise identical configurations, this sensor showed much faster response speed (the time interval to reach half of the magnitude of the steady-state signal, or t{sub 50%}, was only 4 s in response to 1% H{sub 2} without deduction of the delay from the gas delivery system), as well as enhanced signal magnitude (about two times of the former for 1% H{sub 2}). Based on the hydrogen-binding to the traps in the bulk SiO{sub 2}, a mechanism was proposed to explain the very short response time on the device with the ultra-thin SiO{sub 2}. The gate leakage in the device is also discussed. The presented sensor demonstrates a promising step in designing low-cost H{sub 2} detectors with very fast responses. (author)

Lu, Chi [Department of Electrical and Computer Engineering and Center for Nanoscale Science and Engineering, University of Kentucky, Lexington, KY 40506 (United States); National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States); Chen, Zhi [Department of Electrical and Computer Engineering and Center for Nanoscale Science and Engineering, University of Kentucky, Lexington, KY 40506 (United States)

2010-11-15

232

Response of some French beans (Phaseolus vulgaris L) varieties to fast neutron irradiation  

International Nuclear Information System (INIS)

[en] Response of some French beans (Phaseolus vulgaris L.) varieties to fast neutron irradiation. Seeds of French beans varieties, i.e. Local Bandung (white seed), Local Surakarta and Monel (black seed), and Hawaiian Wonder (brown seed) were irradiated with fast neutrons. Irradiation was carried out in the USIF of the TRIGA MARK II Reactor in the Research Centre for Nuclear Techniques Bandung, with doses of 7,5, 15,0, 22,5, 30,0, 37,5 and 45,0 Gy. Irradiated seeds were planted in plastic pots and grown in the green house. The responses of the seedlings to neutron irradiation were observed by measuring the length of hypocotyl, epicotyl and primary leaf size (length and width). The result of the study showed that epicotyl is the most sensitive to fast neutron irradiation followed by primary leaf size and hypocotyl. The D50 for the four varieties measured were significantly different. It was also shown that the black seed varieties were relatively more radioresistant than the other two. (author). 3 figs, 13 refs

1987-01-01

233

Measurement of time performances of the fast component of plastic scintillator fluorescence  

International Nuclear Information System (INIS)

[en] Described is a spectrometer with three counters in a telescope, operating in a single-photon regime, developed for studying the processes of energy transformation in plastic scintillators beginning from the moment of a charged particle getting into a telescope. Considered are the method and results of measuring the time performance (rise time constant and decay time) of the fluorescence fast component for five types of polystyrene scintillators with different additions. The measurements have been performed using photomultipliers. The samples of 1x50x50 mm scintillators were exposed to electrons from a strontium-90 ?-source with a maximum energy of 2.26 MeV. Cherenkov light was used as a zero-time reference in time-distribution measurements. The rise time constant of a scintillator with 2-phenyl-5(4-biphenyl) 1,3,4 oxadiazol (PBD) addition is about 60 ps and the decay time of this scintillator is equal to 1.4 ns. Typical time spectra, obtained from the experimental results and on the base of calculations, are presented. It is pointed out that fluorescence amplitude of a scintillator with PBD addition is two times greater than that of a scintillator with p-terphenyl+POPOP

1980-01-01

234

Fast time resolution measurements of high concentrations of iodine above a Laminaria Digitata seaweed bed  

Science.gov (United States)

We report observations of extremely large concentrations of molecular iodine (I2) measured in situ above a seaweed bed composed of laminaria digitata (90%) and laminaria hyperborea (10%) growing in its natural habitat. Measurements were made off the coast of Roscoff in Brittany, France, during day-time low tides on several days in September and November 2012 with the greatest tidal amplitudes. Iodine was quantified using a portable, battery-powered broadband cavity enhanced absorption spectrometer (BBCEAS) deployed from the in-shore research vessel "Aurelia" operated by the Station Biologique de Roscoff. For the 5 second integration times used here, the BBCEAS instrument has a detection limit for iodine of 12 pptv (parts per trillion by volume). The boat was anchored above the seaweed bed before it was exposed to air by the ebbing tide; the boat was grounded on the seaweed bed around the tidal minimum, and then refloated as the incoming tide covered the seaweed. I2 concentrations were strongly anti-correlated with water depth. Initially little I2 was seen above background levels whilst the blades of the seaweed plants were floating on the water surface. However several hundred pptv of I2 was observed within a few minutes of the plants' stipes breaking the surface and first blades coming to rest on rocks out of the water. Iodine concentrations increased further as the tide ebbed, typically peaking around 1500 pptv around the tidal minimum (by which time the seaweed had been exposed for 45 minutes). I2 concentrations decreased rapidly back to background levels as the returning tide submerged the seaweeds. The concentration profiles showed a lot of high frequency structure, with I2 concentrations commonly varying by a factor 2 (or more) within 60 seconds. Additionally the profiles of I2 emitted from the seaweeds immediately below the instrument's inlet typically sat on a smoothly-varying background of approximately 100 pptv, which we attribute to I2 from other more-distant seaweeds whose emissions are better-mixed into the atmosphere. The peak I2 concentrations observed here are three to five times greater than the maximum amounts recorded above/closeby laminaria beds in previous studies: 350 pptv max in O Grove, Galicia, Spain (Mahajan et al., ACP, 11, 2545, 2011), and 302 and 547 pptv max at Mweenish Bay, near Mace Head, County Galway, Ireland (Huang et al., GRL, 37, L03803, 2010; ACPD, 12, 25915, 2012). In part, the larger peak concentrations seen here are a consequence of deploying a fast response instrument very close to the source, enabling the emission's high temporal variability to be captured with fewer averaging effects. Nevertheless, the I2 concentrations averaged over the 30 minute period around the tidal minimum were still typically 750 pptv, suggesting laminaria beds are even stronger emitters of I2 into coastal atmospheres than previously thought. Some implications for such high concentrations of iodine for the local atmospheric chemistry are considered. We acknowledge support from the European Community FP7 project "ASSEMBLE", grant 227799.

Ball, Stephen; Adams, Thomas; Leblanc, Catherine; Potin, Philippe

2013-04-01

235

Fast elaboration of diagnostic data for real time control in FTU tokamak  

Directory of Open Access Journals (Sweden)

Full Text Available The automatic controller developed for MHD instability control on FTU via the real time (RT) EC launcher [1, 2] is based on the a-priori estimate of the instabilities location and on the fast elaboration of the stream of diagnostic data. A fast data acquisition system, based on existing standard FTU diagnostics, collects thermal and magnetic signals by a 12-channels ECE polychromator [3] and by a set of 22 Mirnov coils respectively. Moreover, the EC time waveform from directional couplers along the transmission line is acquired as well. This set of signals is processed in a timescale significantly shorter than the typical time step of the controller (1ms). RT elaboration algorithms aim at supplying the controller [4] with reliable information about the existence and the spatial location of the instability and about the actual ECRH deposition layer in plasma. The main algorithms blocks are ECE-ECE, ECE-Mirnov and ECE-ECRH cross-correlation, and SVD (Singular Value Decomposition) of Mirnov signals. The capabilities of effective detection, false positive resilience, and mode discrimination will be discussed through the application to actual plasma data.

Alessi E.; Boncagni L.; Botrugno A.; Cirant S.; Galperti C.; Marchetto C.; Nowak S.; Sozzi C.; Tudisco O.

2012-01-01

236

Time and energy response of ZnO:Ga crystal to hard X-ray  

International Nuclear Information System (INIS)

This paper introduces the time response of a new type ZnO. Ga crystal to a fast rep-rate pulse hard X-ray. The hard X-ray energy spectrum (from 10 keV to 100 keV) was measured by X-ray fluorescence analysis apparatus. The results show that the rise time is 316 ps, the FWHM is 440 ps, and the energy response to hard X-ray is flat when the X-ray energy greater than 40 keV. The ZnO:Ga crystal could be used as a component for hard X-ray detection. (authors)

2008-01-01

237

Technical Proposal for the ALICE START Fast Timing Detector Based on Fine-Mesh Phototubes  

CERN Multimedia

Technical Proposal for the ALICE START Fast Timing Detector Based on Fine-Mesh Phototubes A scintillation detector based on fine-mesh phototubes with good timing proporties ( ~ 50 ps) is proposed as a complementary detector for two existing options of the ALICE Forward Multiplicity Detector. Experimental results show high time resolution (up to 35 ps) and high gain in a magnetic field up to 0.5 T of fine-mesh Russian phototubes FEU-527. The proposed detector consists of two arrays of scintillation (or Cherenkov) counters, 24 counters each. The Monte-Carlo simulations made for the proposed design of the detector for p-p collisions give the average efficiency of the detector about 80%. The physical characteristics of the proposed detector are compared with those expected for the MCP version of the FMD.

Kaplin, V A; CERN. Geneva; Loginov, V A; Strikhanov, M N; Gavrilov, Yu K; Filippov, S N; Kurepin, A B; Mayevskaya, A I

1997-01-01

238

Using Graphs for Fast Error Term Approximation of Time-varying Datasets  

Energy Technology Data Exchange (ETDEWEB)

We present a method for the efficient computation and storage of approximations of error tables used for error estimation of a region between different time steps in time-varying datasets. The error between two time steps is defined as the distance between the data of these time steps. Error tables are used to look up the error between different time steps of a time-varying dataset, especially when run time error computation is expensive. However, even the generation of error tables itself can be expensive. For n time steps, the exact error look-up table (which stores the error values for all pairs of time steps in a matrix) has a memory complexity and pre-processing time complexity of O(n2), and O(1) for error retrieval. Our approximate error look-up table approach uses trees, where the leaf nodes represent original time steps, and interior nodes contain an average (or best-representative) of the children nodes. The error computed on an edge of a tree describes the distance between the two nodes on that edge. Evaluating the error between two different time steps requires traversing a path between the two leaf nodes, and accumulating the errors on the traversed edges. For n time steps, this scheme has a memory complexity and pre-processing time complexity of O(nlog(n)), a significant improvement over the exact scheme; the error retrieval complexity is O(log(n)). As we do not need to calculate all possible n2 error terms, our approach is a fast way to generate the approximation.

Nuber, C; LaMar, E C; Pascucci, V; Hamann, B; Joy, K I

2003-02-27

239

Response Time Measurements of the NIF DANTE XRD-31 X-Ray Diodes (Pre-print)  

Energy Technology Data Exchange (ETDEWEB)

The XRD-31 is a fast, windowless X-ray vacuum photodiode developed by EG&G. It is currently the primary fast X-ray detector used to diagnose the X-rays on NIF and OMEGA on the multichannel DANTE spectrometer. The XRD-31 has a dynamic range of less than 1e-12 amps to more than 10 amps. A technique is described to measure the impulse response of the diodes to a 150 fs pulse of 200 nm laser light and a method to calculate the “risetime” for a square pulse and compare it with the computed electron transit time from the photocathode to the anode. Measured response time for 5 XRD-31s assembled in early 2004 was 149.7 ps +-2.75 ps.

Don Pellinen and Michael Griffin

2009-01-23

240

A fasting-induced decrease in plasma glucose concentration does not affect the insulin response to ingested protein in people with type 2 diabetes.  

UK PubMed Central (United Kingdom)

We previously have reported that protein, on a weight basis, is just as potent as glucose in increasing the insulin concentration in people with type 2 diabetes. In people without diabetes, protein is only approximately 30% as potent as glucose in this regard. In the present study, we tested the hypothesis that the increased insulin responsiveness to protein in people with type 2 diabetes is due to the elevated plasma glucose concentration in these individuals. Seven male subjects with untreated type 2 diabetes were given 50 g protein in the form of very lean beef at 8 AM after an overnight fast. On another occasion, the same individuals were fasted for an additional 24 hours to lower their plasma glucose concentration to near the normal reference range. They were then given 50 g protein. The 8 AM glucose concentration was lower after 24 hours of additional fasting, as expected. After ingestion of the protein meal, there was an unexpected, modest increase in glucose concentration after an additional 24 hours of fasting that was not observed with only an overnight fast. Despite the approximately 15% lower plasma glucose concentration at the time of the protein meal, the insulin responses were nearly identical. Thus, the greater insulin response to ingested protein is not likely to be due merely to a higher initial glucose concentration.

Saeed A; Jones SA; Nuttall FQ; Gannon MC

2002-08-01

 
 
 
 
241

Spectral time modal combination (STMC) in response spectrum analysis  

International Nuclear Information System (INIS)

In the piping response spectrum method of analysis, all time phasing among the maximum modal responses is lost. In addition, for multiple support input, the time phasing among the individual support contributions to each modal response is lost. A number of methods have been developed in an attempt to compensate for the lost time phasing; however, none of the methods utilize the methodology of Spectral Time Modal Combination (STMC), which is presented in this paper. (orig.).

1985-01-01

242

Effect of educational kinesiology upon simple response times and choice response times.  

UK PubMed Central (United Kingdom)

The purpose of this study was to determine whether Educational Kinesiology integration movements or repatterning in conjunction with the integration movements affect the response times of college students to a visual stimulus. Ten men and ten women were randomly assigned to each of the three conditions: control, Edu-K movement, or repatterned Edu-K movements. Each subject was pretested on simple and choice response-time tasks. Following the pretest, subjects in the control group sat quietly for 10 minutes. The movement group utilized seven Brain Gym activities. Subjects in the repatterned group experienced Dennison's Laterality Repatterning prior to doing the same Brain Gym activities. All subjects were then retested to assess changes in performance using 30 trials of each task. Statistical analyses indicated significant differences in improvement between the groups on the 4-choice task, with the repatterned group showing greater change than the Edu-K movement-only group, who in turn showed greater improvement than the control group. The groups improved by 6%, 3 1/2%, and 1%, respectively. No group differences were significant on the simple task, although a similar trend was indicated. Men responded faster than women on both tasks; however, the amount of improvement was similar for both.

Sifft JM; Khalsa GC

1991-12-01

243

Fast Inversion Method for Determination of Planetary Parameters from Transit Timing Variations  

CERN Document Server

The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Non-transiting planets in the system can be inferred from TTVs by their gravitational interaction with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Here we describe a fast algorithm that can be used to determine the mass and orbit of the non-transiting planets from the TTV data. We apply our code, ttvim.f, to a wide variety of planetary systems to test the uniqueness of the TTV inversion problem and its dependence on the precision of TTV observations. We find that planetary parameters, including the mass and mutual orbital inclination of planets, can be determined from the TTV datasets that should become available in near future. Unlike the radial velocity technique, the TTV method can therefore be used to characterize the inclination distribution of multi-planet systems.

Nesvorny, David

2009-01-01

244

Response of multiferroic composites inferred from a fast-Fourier-transform-based numerical scheme  

Science.gov (United States)

The effective response and the local fields within periodic magneto-electric multiferroic composites are investigated by means of a numerical scheme based on fast Fourier transforms. This computational framework relies on the iterative resolution of coupled series expansions for the magnetic, electric and strain fields. By using an augmented Lagrangian formulation, a simple and robust procedure which makes use of the uncoupled Green operators for the elastic, electrostatics and magnetostatics problems is proposed. Its accuracy is assessed in the cases of laminated and fibrous two-phase composites for which analytical solutions exist.

Brenner, Renald; Bravo-Castillero, Julián

2010-11-01

245

[Effects of Viscum coloratum flavonoids on fast response action potentials of hearts].  

Science.gov (United States)

The effects of the total flavonoids of Viscum coloratum (VCF) on the fast response action potentials (FAP) of canine Purkinje fibers and guinea pig ventricular papillary muscles were studied by glass-microelectrode technique. The effects of VCF on the ionic currents through cellular membrane were analysed with selective ion blockers (CsCl, verapamil, and TEA+), respectively. VCF (100 micrograms.ml-1) accelerated the repolarization of FAP and increased delta ERP/delta APD ratio, which were related to decreasing Isi and increasing Ix. It was suggested that the anti-tachyarrhythmic mechanism of VCF was attributed to prolonging ERP relatively and to abolishing reentrant excitation. PMID:8010115

Wu, J X; Yu, G R; Wang, B Y; Zhong, D S; Huang, D J

1994-03-01

246

[Effects of Viscum coloratum flavonoids on fast response action potentials of hearts  

UK PubMed Central (United Kingdom)

The effects of the total flavonoids of Viscum coloratum (VCF) on the fast response action potentials (FAP) of canine Purkinje fibers and guinea pig ventricular papillary muscles were studied by glass-microelectrode technique. The effects of VCF on the ionic currents through cellular membrane were analysed with selective ion blockers (CsCl, verapamil, and TEA+), respectively. VCF (100 micrograms.ml-1) accelerated the repolarization of FAP and increased delta ERP/delta APD ratio, which were related to decreasing Isi and increasing Ix. It was suggested that the anti-tachyarrhythmic mechanism of VCF was attributed to prolonging ERP relatively and to abolishing reentrant excitation.

Wu JX; Yu GR; Wang BY; Zhong DS; Huang DJ

1994-03-01

247

Seismic response analysis for the main vessel of pool-type fast breeder reactor  

International Nuclear Information System (INIS)

The structure of pool-type fast breeder reactor (FBR) is quite simplified in order that the calculation model may both be reflecting the structural dynamic characteristics and convenient to compute it. A simple spring-mass system could be approximatively in effect replacing a complex structure. The vessel deformation and appointed dynamic fluid pressure suppositions are taken. The motion equation of the system under horizontal seismic ground motion can be obtained by means of virtual displacement principle. Finally, the seismic response of the structure is computed

2000-01-01

248

Slowed down: response time deficits in well recovered subjects with incomplete spinal cord injury.  

UK PubMed Central (United Kingdom)

OBJECTIVE: : To quantify remaining motor deficits in well recovered subjects with incomplete spinal cord injury. DESIGN: : Case-control study. SETTING: : SCI center of a university hospital in Switzerland PARTICIPANTS: : Out of a volunteer sample we recruited 15 subjects with incomplete paraplegia (mean age 50 years, 67% men, neurological level from T4 to L4, mean time since injury 6.3 years) and close-to-normal walking pattern. They were compared with 15 age- and gender-matched controls. INTERVENTIONS: : Not applicable. MAIN OUTCOME MEASURES: : Response time and its 4 subparts processing time, conduction time, motor time and movement time. These were assessed with an electromyography-supported lower limb response time task and single-pulse transcranial magnetic stimulation to measure the motor evoked potential latency of the M. tibialis anterior. Additionally, participants were tested for lower extremity muscle strength, gait capacity, visual acuity and upper extremity response time. RESULTS: : Well recovered subjects with incomplete paraplegia still suffered from deficits in conduction and movement time, whereas their processing and motor times were essentially normal. Additionally, these patients also showed delayed movement times of the upper limb, even if their injury was located in the thoracic or lumbar region. CONCLUSIONS: : Well recovered patients with incomplete paraplegia still experience difficulties with quick and accurate movements. Furthermore, combining transcranial magnetic stimulation, electromyography and a response time task proved useful for investigating deficits in executing fast and accurate movements.

Labruyère R; Zimmerli M; van Hedel HJ

2013-04-01

249

Vlasov-Fokker-Planck simulations of fast-electron transport with hydrodynamic plasma response  

International Nuclear Information System (INIS)

We report on kinetic simulations of the transport of laser-produced relativistic electron beams (REB) through solid-density plasma, including the hydrodynamic response of the plasma. We consider REBs with parameters relevant to fast-ignition of compressed inertial confinement fusion capsules. We show that over the 10-20ps timescales required for fast-ignition, thermal pressure (from Ohmic heating) can significantly modify the density which in turn strongly affects the propagation of injected fast-electrons; it allows them to re-collimate into a narrow, intense beam under conditions where they initially undergo beam-hollowing. Similar static-density calculations do not show re-collimation. The re-collimation effect is attributed to PdV cooling in the pressure-induced density-channel, which in turn suppresses defocusing magnetic fields generated by resistivity gradients. These simulations have been carried out using the new 2D-3V Vlasov-Fokker-Planck (VFP) code FIDO running in hybrid mode.

2010-08-01

250

Fast simulation of reconstructed phylogenies under global time-dependent birth-death processes.  

UK PubMed Central (United Kingdom)

MOTIVATION: Diversification rates and patterns may be inferred from reconstructed phylogenies. Both the time-dependent and the diversity-dependent birth-death process can produce the same observed patterns of diversity over time. To develop and test new models describing the macro-evolutionary process of diversification, generic and fast algorithms to simulate under these models are necessary. Simulations are not only important for testing and developing models but play an influential role in the assessment of model fit. RESULTS: In the present article, I consider as the model a global time-dependent birth-death process where each species has the same rates but rates may vary over time. For this model, I derive the likelihood of the speciation times from a reconstructed phylogenetic tree and show that each speciation event is independent and identically distributed. This fact can be used to simulate efficiently reconstructed phylogenetic trees when conditioning on the number of species, the time of the process or both. I show the usability of the simulation by approximating the posterior predictive distribution of a birth-death process with decreasing diversification rates applied on a published bird phylogeny (family Cettiidae). AVAILABILITY: The methods described in this manuscript are implemented in the R package TESS, available from the repository CRAN (http://cran.r-project.org/web/packages/TESS/). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Höhna S

2013-06-01

251

Sources of uncertainty in eddy covariance ozone flux measurements made by dry chemiluminescence fast response analysers  

Directory of Open Access Journals (Sweden)

Full Text Available Eddy covariance ozone flux measurements are the most direct way to estimate ozone removal near the surface. Over vegetated surfaces, high quality ozone fluxes are required to probe the underlying processes for which it is necessary to separate the flux into the components of stomatal and non-stomatal deposition. Detailed knowledge of the processes that control non-stomatal deposition is limited and more accurate ozone flux measurements are needed to quantify this component of the deposited flux. We present a systematic intercomparison study of eddy covariance ozone flux measurements made using two fast response dry chemiluminescence analysers. Ozone deposition was measured over a well characterised managed grassland near Edinburgh, Scotland, during August 2007. A data quality control procedure specific to these analysers is introduced. Absolute ozone fluxes were calculated based on the relative signals of the dry chemiluminescence analysers using three different calibration methods and the results are compared for both analysers. It is shown that the error in the fitted parameters required for the flux calculations provides a substantial source of uncertainty in the fluxes. The choice of the calculation method itself can also constitute an uncertainty in the flux as the calculated fluxes by the three methods do not agree within error at all times. This finding highlights the need for a consistent and rigorous approach for comparable data-sets, such as e.g. in flux networks. Ozone fluxes calculated by one of the methods were then used to compare the two analysers in more detail. This systematic analyser comparison reveals half-hourly flux values differing by up to a factor of two at times with the difference in mean hourly flux ranging from 0 to 23% with an error in the mean daily flux of ±12%. The comparison of analysers shows that the agreement in fluxes is excellent for some days but that there is an underlying uncertainty as a result of variable analyser performance and/or non-linear behaviour of disc sensitivity.

J. B. A. Muller; C. J. Percival; M. W. Gallagher; D. Fowler; M. Coyle; E. Nemitz

2009-01-01

252

Time Domain Response of Biconical Horns.  

Science.gov (United States)

Time domain reflectometry derived from 40 GHz vector network analyser data is used to analyse a pair of biconical horn antennas. Such a technique provides insight into the operation of these antennas and is useful to the designer who wishes to optimise pe...

K. M. Harvey

1992-01-01

253

Transcriptomic and metabolomic profiling of chicken adipose tissue in response to insulin neutralization and fasting  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Domestic broiler chickens rapidly accumulate adipose tissue due to intensive genetic selection for rapid growth and are naturally hyperglycemic and insulin resistant, making them an attractive addition to the suite of rodent models used for studies of obesity and type 2 diabetes in humans. Furthermore, chicken adipose tissue is considered as poorly sensitive to insulin and lipolysis is under glucagon control. Excessive fat accumulation is also an economic and environmental concern for the broiler industry due to the loss of feed efficiency and excessive nitrogen wasting, as well as a negative trait for consumers who are increasingly conscious of dietary fat intake. Understanding the control of avian adipose tissue metabolism would both enhance the utility of chicken as a model organism for human obesity and insulin resistance and highlight new approaches to reduce fat deposition in commercial chickens. Results We combined transcriptomics and metabolomics to characterize the response of chicken adipose tissue to two energy manipulations, fasting and insulin deprivation in the fed state. Sixteen to 17 day-old commercial broiler chickens (ISA915) were fed ad libitum, fasted for five hours, or fed but deprived of insulin by injections of anti-insulin serum. Pair-wise contrasts of expression data identified a total of 2016 genes that were differentially expressed after correction for multiple testing, with the vast majority of differences due to fasting (1780 genes). Gene Ontology and KEGG pathway analyses indicated that a short term fast impacted expression of genes in a broad selection of pathways related to metabolism, signaling and adipogenesis. The effects of insulin neutralization largely overlapped with the response to fasting, but with more modest effects on adipose tissue metabolism. Tissue metabolomics indicated unique effects of insulin on amino acid metabolism. Conclusions Collectively, these data provide a foundation for further study into the molecular basis for adipose expansion in commercial poultry and identify potential pathways through which fat accretion may be attenuated in the future through genetic selection or management practices. They also highlight chicken as a useful model organism in which to study the dynamic relationship between food intake, metabolism, and adipose tissue biology.

Ji Bo; Ernest Ben; Gooding Jessica R; Das Suchita; Saxton Arnold M; Simon Jean; Dupont Joelle; Métayer-Coustard Sonia; Campagna Shawn R; Voy Brynn H

2012-01-01

254

Thyroid hormone regulation of Sirtuin 1 expression and implications to integrated responses in fasted mice.  

UK PubMed Central (United Kingdom)

Sirtuin 1 (SIRT1), a NAD(+)-dependent deacetylase, has been connected to beneficial effects elicited by calorie restriction. Physiological adaptation to starvation requires higher activity of SIRT1 and also the suppression of thyroid hormone (TH) action to achieve energy conservation. Here, we tested the hypothesis that those two events are correlated and that TH may be a regulator of SIRT1 expression. Forty-eight-hour fasting mice exhibited reduced serum TH and increased SIRT1 protein content in liver and brown adipose tissue (BAT), and physiological thyroxine replacement prevented or attenuated the increment of SIRT1 in liver and BAT of fasted mice. Hypothyroid mice exhibited increased liver SIRT1 protein, while hyperthyroid ones showed decreased SIRT1 in liver and BAT. In the liver, decreased protein is accompanied by reduced SIRT1 activity and no alteration in its mRNA. Hyperthyroid and hypothyroid mice exhibited increases and decreases in food intake and body weight gain respectively. Food-restricted hyperthyroid animals (pair-fed to euthyroid group) exhibited liver and BAT SIRT1 protein levels intermediary between euthyroid and hyperthyroid mice fed ad libitum. Mice with TH resistance at the liver presented increased hepatic SIRT1 protein and activity, with no alteration in Sirt1 mRNA. These results suggest that TH decreases SIRT1 protein, directly and indirectly, via food ingestion control and, in the liver, this reduction involves TR?. The SIRT1 reduction induced by TH has important implication to integrated metabolic responses to fasting, as the increase in SIRT1 protein requires the fasting-associated suppression of TH serum levels.

Cordeiro A; de Souza LL; Oliveira LS; Faustino LC; Santiago LA; Bloise FF; Ortiga-Carvalho TM; Almeida NA; Pazos-Moura CC

2013-02-01

255

Development of turbochargers with reduced response time during acceleration  

Energy Technology Data Exchange (ETDEWEB)

The response time of the turbocharger during an acceleration is considered today as a prime objective for improvement for passenger car turbocharged engines. This paper is an attempt to characterize the effects of turbocharger response time reduction on car performances and driveability as perceived by the user. Turbocharger evolutions for reduced response time are described and results obtained by Garrett Automotive Products Company in the field of variable nozzle turbine and ceramic turbine wheel are analysed and discussed.

Parois, A.

1985-01-01

256

Response times of operators in a control room  

International Nuclear Information System (INIS)

A statistical analysis was made of operator response times recorded in the control room of a research reactor during the years 1972-1974. A homogeneity test revealed that the data consist of a mixture of populations. A small but statistically significant difference is found between day and night response times. Lognormal distributions are found to provide the best fit of the day and the night response times. (author)

1982-01-01

257

The first synchrotron infrared beamlines at the Advanced Light Source: Spectromicroscopy and fast timing  

Energy Technology Data Exchange (ETDEWEB)

Two recently commissioned infrared beamlines on the 1.4 bending magnet port at the Advanced Light Source, LBNL, are described. Using a synchrotron as an IR source provides three primary advantages: increased brightness, very fast light pulses, and enhanced far-IR flux. The considerable brightness advantage manifests itself most beneficially when performing spectroscopy on a microscopic length scale. Beamline (BL) 1.4.3 is a dedicated FTIR spectromicroscopy beamline, where a diffraction-limited spot size using the synchrotron source is utilized. BL 1.4.2 consists of a vacuum FTIR bench with a wide spectral range and step-scan capability. This BL makes use of the pulsed nature of the synchrotron light as well as the far-IR flux. Fast timing is demonstrated by observing the pulses from the electron bunch storage pattern at the ALS. Results from several experiments from both IR beamlines will be presented as an overview of the IR research currently being done at the ALS.

Martin, Michael C.; McKinney, Wayne R.

1999-09-01

258

The First Synchrotron Infrared Beamlines at the ALS Spectromicroscopy and Fast Timing  

CERN Multimedia

Two recently commissioned infrared beamlines on the 1.4 bending magnet port at the Advanced Light Source, LBNL, are described. Using a synchrotron as an IR source provides three primary advantages: increased brightness, very fast light pulses, and enhanced far-IR flux. The considerable brightness advantage manifests itself most beneficially when performing spectroscopy on a microscopic length scale. Beamline (BL) 1.4.3 is a dedicated FTIR spectromicroscopy beamline, where a diffraction-limited spot size using the synchrotron source is utilized. BL 1.4.2 consists of a vacuum FTIR bench with a wide spectral range and step-scan capability. This BL makes use of the pulsed nature of the synchrotron light as well as the far-IR flux. Fast timing is demonstrated by observing the pulses from the electron bunch storage pattern at the ALS. Results from several experiments from both IR beamlines will be presented as an overview of the IR research currently being done at the ALS.

Martin, M C; Martin, Michael C.; Kinney, Wayne R. Mc

1999-01-01

259

The first synchrotron infrared beamlines at the Advanced Light Source: Spectromicroscopy and fast timing  

International Nuclear Information System (INIS)

Two recently commissioned infrared beamlines on the 1.4 bending magnet port at the Advanced Light Source, LBNL, are described. Using a synchrotron as an IR source provides three primary advantages: increased brightness, very fast light pulses, and enhanced far-IR flux. The considerable brightness advantage manifests itself most beneficially when performing spectroscopy on a microscopic length scale. Beamline (BL) 1.4.3 is a dedicated FTIR spectromicroscopy beamline, where a diffraction-limited spot size using the synchrotron source is utilized. BL 1.4.2 consists of a vacuum FTIR bench with a wide spectral range and step-scan capability. This BL makes use of the pulsed nature of the synchrotron light as well as the far-IR flux. Fast timing is demonstrated by observing the pulses from the electron bunch storage pattern at the ALS. Results from several experiments from both IR beamlines will be presented as an overview of the IR research currently being done at the ALS.

1999-01-01

260

Observations of plasma response to RMP using fast movable magnetic probe on TEXTOR  

Energy Technology Data Exchange (ETDEWEB)

Plasma response to resonant magnetic perturbation fields (RMPs) is important for understanding the physical mechanism of instability control using RMP fields in the next generation of fusion devices, i.e. ITER. Such an investigation has been carried out in TEXTOR under different dynamic ergodic divertor (DED) configurations. The perturbed magnetic field is measured by the Fast Movable Magnetic Probe (FMMP) installed at the outer equatorial plane (low-field side). Preliminary results show that the perturbed plasma edge magnetic topology is different from the case simulated with a vacuum assumption. Plasma response to RMP depends strongly on both the location of the resonant rational flux surface and the frequency difference between the drift of the rational surface in the plasma and the external perturbation.

Yang, Yao; Liang, Yunfeng; Sun, Youwen; Zhang, Tao; Assmann, Jochen; Bertschinger, Guenter; Jaegers, Hubert; Koslowski, Hans Rudolf; Pearson, Jonathan; Schweer, Bernd; Wiegmann, Christopher; Xu, Yuhong [Institute of Energy and Climate Research/Plasma Physics, Forschungszentrum Juelich GmbH, Association EURATOM-FZJ, Juelich (Germany)

2011-07-01

 
 
 
 
261

Observations of plasma response to RMP using fast movable magnetic probe on TEXTOR  

International Nuclear Information System (INIS)

[en] Plasma response to resonant magnetic perturbation fields (RMPs) is important for understanding the physical mechanism of instability control using RMP fields in the next generation of fusion devices, i.e. ITER. Such an investigation has been carried out in TEXTOR under different dynamic ergodic divertor (DED) configurations. The perturbed magnetic field is measured by the Fast Movable Magnetic Probe (FMMP) installed at the outer equatorial plane (low-field side). Preliminary results show that the perturbed plasma edge magnetic topology is different from the case simulated with a vacuum assumption. Plasma response to RMP depends strongly on both the location of the resonant rational flux surface and the frequency difference between the drift of the rational surface in the plasma and the external perturbation.

2011-01-01

262

A Box-Cox normal model for response times.  

UK PubMed Central (United Kingdom)

The log-transform has been a convenient choice in response time modelling on test items. However, motivated by a dataset of the Medical College Admission Test where the lognormal model violated the normality assumption, the possibilities of the broader class of Box-Cox transformations for response time modelling are investigated. After an introduction and an outline of a broader framework for analysing responses and response times simultaneously, the performance of a Box-Cox normal model for describing response times is investigated using simulation studies and a real data example. A transformation-invariant implementation of the deviance information criterium (DIC) is developed that allows for comparing model fit between models with different transformation parameters. Showing an enhanced description of the shape of the response time distributions, its application in an educational measurement context is discussed at length.

Klein Entink RH; van der Linden WJ; Fox JP

2009-11-01

263

A Box-Cox normal model for response times.  

Science.gov (United States)

The log-transform has been a convenient choice in response time modelling on test items. However, motivated by a dataset of the Medical College Admission Test where the lognormal model violated the normality assumption, the possibilities of the broader class of Box-Cox transformations for response time modelling are investigated. After an introduction and an outline of a broader framework for analysing responses and response times simultaneously, the performance of a Box-Cox normal model for describing response times is investigated using simulation studies and a real data example. A transformation-invariant implementation of the deviance information criterium (DIC) is developed that allows for comparing model fit between models with different transformation parameters. Showing an enhanced description of the shape of the response time distributions, its application in an educational measurement context is discussed at length. PMID:19187574

Klein Entink, R H; van der Linden, W J; Fox, J-P

2009-01-30

264

Fast Rise Time High Voltage Pulse Generator Applying The Marx Generator  

Energy Technology Data Exchange (ETDEWEB)

A compact size high voltage pulse generator with nanosecond rise time has been designed and investigated experimentally. The inductance of a pulse generator can be reduced by fixing the Marx generator and pulse forming network components into a single cylindrical unit. As a result, nanosecond rise time about 8{approx}10[ns] and pulse width of several hundred [ns] can be obtained from a modified Marx pulse generator. And parametric studies showed that the rise time of the output pulse was depended little on the change of the load resistance and the charging capacitance while the pulse width of the output pulse was depended greatly upon the change of the load resistance and the charging capacitance. The theoretical simulation results of the Marx generators from equivalent circuit agreed well with the experimental results in 10%, and which showed the possibility to design the laboratory-size pulse generator very fast rising time and a proper pulse width by minimizing stray inductance and varying resistance and capacitance. (author). 17 refs., 8 figs., 1 tab.

Park, S. L.; Kim, J. G.; Moon, J. D. [Kyungpook National University, Taegu (Korea); Chung, S. H. [Sangrok Korea Co. Ltd., Taegu (Korea)

2001-02-01

265

System-level Specifications of the Timing and Fast Control system for the LHCb Upgrade  

CERN Multimedia

The LHCb experiment has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times the initial design luminosity. The various sub-systems in the readout architecture will need to be upgraded in order to cope with higher sub-detector occupancies, higher rate and higher network load. In this paper, we describe the specifications of the new Timing and Fast Control (S- TFC) system. We define the requirements for the new S-TFC, and specify its architecture and the individual components. The system is based on a single new Readout Supervisor (S-ODIN) instantiating several S-TFC masters to allow partitioning. The communication with the readout electronics is ensured by a shared high-speed optical link network for both the distribution of timing and synchronous control information, as well as trigger/throttle communication. An interface board (SOL40) with fan-out capabilities for timing and synchronous information and fan-in capabilities for throttle and rate regulation of the...

Alessio, Federico

2013-01-01

266

A UV LED-based fast-pulsed photoelectron source for time-of-flight studies  

International Nuclear Information System (INIS)

[en] We report on spectroscopy and time-of-flight measurements using an 18 keV fast-pulsed photoelectron source of adjustable intensity, ranging from single photoelectrons per pulse to 5 photoelectrons per ?s at pulse repetition rates of up to 10 kHz. Short pulses between 40 ns and 4 ?s in length were produced by switching light emitting diodes with central output wavelengths of 265 and 257 nm, in the deep ultraviolet (or UV-C) regime, at kHz frequencies. Such photoelectron sources can be useful calibration devices for testing the properties of high-resolution electrostatic spectrometers, like the ones used in current neutrino mass searches.

2009-01-01

267

On very fast frequence drifting solar radiobursts with short time of decay  

International Nuclear Information System (INIS)

[en] An analysis of the radio echo probing of the Sun data reveals the existence of the regions of the rapid acceleration and intense heating of the solar wind (RAIH) 2.4. Investigations are made to find out what peculiarities are acquired by the bursts of type 3 excited in RAIH. Numerical solution of the equations governing the evolution of the Langmuir waves spectrum excited by the electron beam enables us to demonstrate that along with a very fast frequency drift these bursts are distinguished by the very short time of decay determined by the Landau damping. The anticipation is made that the pulsating structures or groups of spikes, especially those connected with bursts of type 3 appearing on the lower frequencies 18.21, are excited in RAIH

1976-01-01

268

Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei  

Energy Technology Data Exchange (ETDEWEB)

Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for {sup 32}Mg and {sup 96}Pd, they include the first determination of the half-life of the 8{sup +} state in {sup 80}Ge, T{sub 1/2} = 2.95(6) ns, and significantly more precise results for {sup 51}Mn (3680 keV level) and {sup 48}V (421 keV level), T{sub 1/2} = 1760(40) ps and T{sub 1/2} {<=} 135 ps, respectively. Development of new scintillators will steadily improve precision and sensitivity of future measurements.

Mach, H [Department of Radiation Sciences, Uppsala University, S-75121 Uppsala (Sweden); Walker, P M [Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Julin, R [Department of Physics, PO Box 35 (YFL), FIN-40014 University of Jyvaeskylae (Finland)] [and others

2005-10-01

269

In-beam fast-timing measurements in 103,105,107Cd  

CERN Multimedia

Fast-timing measurements were performed recently in the region of the medium-mass 103,105,107Cd isotopes, produced in fusion evaporation reactions. Emitted gamma-rays were detected by eight HPGe and five LaBr3:Ce detectors working in coincidence. Results on new and re-evaluated half-lives are discussed within a systematic of transition rates. The $7/2_1^+$ states in 103,105,107Cd are interpreted as arising from a single-particle excitation. The half-life analysis of the $11/2_1^-$ states in 103,105,107Cd shows no change in the single-particle transition strength as a function of the neutron number.

Kisyov, S; Marginean, N; Bucurescu, D; Atanasova, L; Balabanski, D L; Cata-Danil, Gh; Cata-Danil, I; Daugas, J -M; Deleanu, D; Detistov, P; Filipescu, D; Georgiev, G; Ghita, D; Glodariu, T; Jolie, J; Judson, D S; Lozeva, R; Marginean, R; Mihai, C; Negret, A; Pascu, S; Radulov, D; Regis, J -M; Rudigier, M; Sava, T; Stroe, L; Suliman, G; Zamfir, N V; Zell, K O; Zhekova, M

2011-01-01

270

Real time measurement of crystal growth by glancing angle scattering of fast ions  

International Nuclear Information System (INIS)

We have constructed a new system for real time measurements of crystal growth by glancing angle scattering of fast ions. The system is composed of a microchannel plate, a fluorescence screen and a CCD video camera in order to measure the dynamical change in the angular distribution of the scattered ions during crystal growth. Initial stage of epitaxial growth of lead chalcogenides on SnTe (100) under UHV conditions is studied with the system. Anomalous broadening of the angular distribution of scattered 0.7-MeV He ions is observed when the thickness of the growing layer is between 1 and about 10 nm. From the Monte Carlo simulation of ion trajectories at glancing angle scattering from several model surfaces, this anomaly is attributed to the surface wrinkles caused by a square network of misfit edge dislocations. (orig.)

1993-01-01

271

The first synchrotron infrared beamlines at the Advanced Light Source: Microspectroscopy and fast timing  

International Nuclear Information System (INIS)

[en] A set of new infrared (IR) beamlines on the 1.4 bending magnet port at the Advanced Light Source, LBNL, are described. Using a synchrotron as an IR source provides considerable brightness advantages, which manifests itself most beneficially when performing spectroscopy on a microscopic length scale. Beamline (BL) 1.4.3 is a dedicated microspectroscopy beamline, where the much smaller focused spot size using the synchrotron source is utilized. This enables an entirely new set of experiments to be performed where spectroscopy on a truly microscopic scale is now possible. BL 1.4.2 consists of a vacuum FTIR bench with a wide spectral range and step-scan capabilities. The fast timing is demonstrated by observing the synchrotron electron storage pattern at the ALS

1998-01-01

272

Web Service Response Time Monitoring: Architecture and Validation  

Directory of Open Access Journals (Sweden)

Full Text Available Web services are used in many Web applications in order to save time and cost during software development process. To peruse Web service response time, a suitable tool is needed to automate the measurement of the response time. However, not many suitable tools are available for automatic measurement of response time. This research is carried out in the context of quality of Web services in order to measure and visualize Web service response time. The method proposed in this research for accomplishing this goal is based on creating a proxy for connecting to the required Web service, and then calculating the Web services response time via the proxy. A software tool is designed based on the proposed method in order to guide the implementation that is still in progress. The tool can be validated through empirical validation using three test cases for three different Web service access situations.

Sara Abbaspour Asadollah; Thiam Kian Chiew

2012-01-01

273

Dynamic Response of a fast near infra-red Mueller matrix ellipsometer  

CERN Multimedia

The dynamic response of a near infrared Ferroelectric Liquid Crystal based Mueller matrix ellipsometer (NIR FLC-MME) is presented. A time dependent simulation model, using the measured time response of the individual FLCs, is used to describe the measured temporal response. Furthermore, the impulse response of the detector and the pre-amplifier is characterized and included in the simulation model. The measured time-dependent intensity response of the MME is reproduced in simulations, and it is concluded that the switching time of the FLCs is the limiting factor for the Mueller matrix measurement time of the FLC-based MME. Based on measurements and simulations our FLC based NIR-MME system is estimated to operate at the maximum speed of approximately 16 ms per Mueller matrix measurement. The FLC-MME may be operated several times faster, since the switching time of the crystals depends on the individual crystal being switched, and to what state it is switched. As a demonstration, the measured temporal response ...

Aas, Lars Martin Sandvik; Kildemo, Morten; Lindgren, Mikael

2010-01-01

274

Organic scintillators response function modeling for Monte Carlo simulation of Time-of-Flight measurements.  

Science.gov (United States)

In neutron Time-of-Flight (TOF) measurements performed with fast organic scintillation detectors, both pulse arrival time and amplitude are relevant. Monte Carlo simulation can be used to calculate the time-energy dependant neutron flux at the detector position. To convert the flux into a pulse height spectrum, one must calculate the detector response function for mono-energetic neutrons. MCNP can be used to design TOF systems, but standard MCNP versions cannot reliably calculate the energy deposited by fast neutrons in the detector since multiple scattering effects must be taken into account in an analog way, the individual recoil particles energy deposit being summed with the appropriate scintillation efficiency. In this paper, the energy response function of 2?×2? and 5?×5? liquid scintillation BC-501 A (Bicron) detectors to fast neutrons ranging from 20 keV to 5.0 MeV is computed with GEANT4 to be coupled with MCNPX through the "MCNP Output Data Analysis" software developed under ROOT (Carasco, 2010). PMID:22100378

Carasco, C

2011-11-11

275

Organic scintillators response function modeling for Monte Carlo simulation of Time-of-Flight measurements.  

UK PubMed Central (United Kingdom)

In neutron Time-of-Flight (TOF) measurements performed with fast organic scintillation detectors, both pulse arrival time and amplitude are relevant. Monte Carlo simulation can be used to calculate the time-energy dependant neutron flux at the detector position. To convert the flux into a pulse height spectrum, one must calculate the detector response function for mono-energetic neutrons. MCNP can be used to design TOF systems, but standard MCNP versions cannot reliably calculate the energy deposited by fast neutrons in the detector since multiple scattering effects must be taken into account in an analog way, the individual recoil particles energy deposit being summed with the appropriate scintillation efficiency. In this paper, the energy response function of 2?×2? and 5?×5? liquid scintillation BC-501 A (Bicron) detectors to fast neutrons ranging from 20 keV to 5.0 MeV is computed with GEANT4 to be coupled with MCNPX through the "MCNP Output Data Analysis" software developed under ROOT (Carasco, 2010).

Carasco C

2012-07-01

276

The Effect of Holly Fasting Month of Ramadan on the Delayed Type Hypersensitivity Response to Purified Protein Derivative  

Directory of Open Access Journals (Sweden)

Full Text Available Studies during recent decade indicate that low calorie intake has potentiating effect on immune response . So the effect of fasting in holly month of Ramadan on cellular immune was studied. In this study , delayed type hypersensitivity (DTH) to purified protein derivative (PPD) test was selected to evaluate cellular immune response , because this test is not only very simple but also is valuable and reliable. This research studied DTH to PPD in two groups of students before and after the holly fasting month of Ramadan. The range of age in the both groups was 20-30 year. Mantoux method was the selected method to evaluate DTH response to PPD. DTH response to PPD in fasting group increased from 8.8 to 13 mm , which is statistically significant (P<0.05). It is noticeable that the differences between the rates of increasing DTH response to PPD in control group and fasting group was statistically significant (P<0.05). Based on the above finding it can be concluded that fasting has potentiating effect on cellular immune response.

M. Rahmani; M. Zarei

2003-01-01

277

Control dynamics and timing a discrete motor response.  

UK PubMed Central (United Kingdom)

Altering the resistive dynamics of a handle moved 60 cm. to fill a 2-sec. interval manipulated the proprioceptive feedback (PFB) from the response. Spelling aloud 2-, 3-, and 4-letter words during the motor response prevented overt counting. 84 11-14 year old boys were given immediate KR, the lapsed time for the motor response, for 50 or 60 trials according to the design. Only the condition reducing time varying PFB to a minimum, no movement and no spelling, prevented accurate timing of the responses, but above the minimal level, accuracy, consistency and rapidity of learning was increased by the addition of large resistances varying with velocity and acceleration.

Ellis MJ

1969-06-01

278

Hierarchical Diffusion Models for Two-Choice Response Times  

Science.gov (United States)

Two-choice response times are a common type of data, and much research has been devoted to the development of process models for such data. However, the practical application of these models is notoriously complicated, and flexible methods are largely nonexistent. We combine a popular model for choice response times--the Wiener diffusion…

Vandekerckhove, Joachim; Tuerlinckx, Francis; Lee, Michael D.

2011-01-01

279

Linking Response-Time Parameters onto a Common Scale  

Science.gov (United States)

|Although response times on test items are recorded on a natural scale, the scale for some of the parameters in the lognormal response-time model (van der Linden, 2006) is not fixed. As a result, when the model is used to periodically calibrate new items in a testing program, the parameter are not automatically mapped onto a common scale. Several…

van der Linden, Wim J.

2010-01-01

280

Fast and Accurate Method for Determining a Lower Bound on Execution Time  

UK PubMed Central (United Kingdom)

In performance critical applications, memory latency is frequently the dominant overhead. In many cases, automatic compiler-based optimizations to improve memory performance are limited and programmers frequently resort to manual optimization techniques. However, this process is tedious and time-consuming. Furthermore, as the potential benefit from optimization is unknown there is no way to judge the amount of effort worth expending, nor when the process can stop, i.e. when optimal memory performance has been achieved or sufficiently approached. Architecture simulators can provide such information but designing an accurate model of an existing architecture is difficult and simulation times are excessively long. In this article, we propose and implement a technique that is both fast and reasonably accurate for estimating a lower bound on execution time for scientific applications. This technique has been tested on a wide range of programs from the SPEC benchmark suite and two commercial applications, where it has been used to guide a manual optimization process and iterative compilation. We compare our technique with that of a simulator with an ideal memory behaviour and demonstrate that our technique provides comparable information on memory performance and yet is over two orders of magnitude faster. We further show that our technique is considerably more accurate than hardware counters. KEY WORDS: memory performance; optimization tool; memory latency analysis

G. Fursin

 
 
 
 
281

Study of Fast Pulsars Using Continuous Time Tagged Events from the GBM Detectors  

Science.gov (United States)

The time tagged event (TTE) data from the Gamma-ray Burst Monitor (GBM) onboard the Fermi Gamma-ray Space Telescope have excellent time resolution of 2 usec. Untriggered TTE data from the 12 Sodium Iodide (NaI which operate in the gamma-ray energy range: 10-1000 keV) and 2 Bismuth Germanate (BGO which operate in the gamma-ray energy range: 0.15-40 MeV) detectors have been produced since July 2010. These are being generated only within pre-defined boxes in the Fermi orbit, which are designed for the study of Terrestrial Gamma-ray Flashes (TGF). Using these data we obtain pulse profiles for the Crab pulsar by the well known epoch folding technique. The phasogram exhibits both the main and the inter-pulse as expected. Our sensitivity calculations show that we may be able to produce similar pulse profiles for weaker fast pulsars like the Vela pulsar and Geminga using the continuous TTE data. We need to integrate the data over longer ( 106 s) exposure times in order detect weaker signals from these pulsars. This would entail the production of TTE data continuously through out the orbit. The measurement of pulsed fluxes from these pulsars in the GBM energy range will enhance the Science capability of Fermi. In addition, we can also search for untriggered weak GRBs as well as other galactic transients and investigate their location and spectral information.

Bhat, Narayana P.; Finger, M. H.; Jenke, P. A.; Camero-Arranz, A.; Wilson-Hodge, C. A.; Briggs, M. S.

2012-01-01

282

Development of a fast-timing LaBr3(Ce) array for NuSTAR  

International Nuclear Information System (INIS)

[en] The development of a new fragment separator (Super-FRS) at the future Facility for Anti-proton and Ion Research (FAIR) will allow the study of proton- and neutron-rich short-lived nuclei. As one of the nine proposed set-ups established under the NuSTAR international collaboration, the DESPEC group plan to develop a new fast-timing array to be located at the focal point of the separator, which will use LaBr3(Ce) scintillators to measure the half-lives of excited states in these exotic nuclei. In order to optimise the efficiency of the array while maintaining the intrinsically good timing properties of the detectors, Monte-Carlo simulations will be carried out for 1, 1.5 and 2'' cylindrical and 1×1.5×1.5'' conical detectors. These simulations will inform the final design of the array based on the criteria of efficiency as a function of ?-ray energy, and timing performance. The simulations will be validated by comparing them with the results of an experiment at Bucharest, where sub-nanosecond lifetime measurements were successfully performed for excited states in 138Ce. The results of the simulations will dictate the final design, and how it will be used in future experimental conditions.

2012-09-18

283

Function parametrization applied to capacitive pressure sensor response time  

International Nuclear Information System (INIS)

[en] The response time associated to monitoring pressure sensors, can be estimated from a set of measurements based on power spectral density of pressure fluctuations (PSD). Surveillance and predictive analysis methods are important for achieving a monitoring of pressure sensors. The function parametrization method is an information treatment technique, that allows setting a relationship between a set of measurements, or input (in this case the frequencies associated to the real and complex poles appearing in the PSD), and the physical parameters, or outputs (response time) of a system (the pressure sensors). These measurements and response time proceed from a database, subjected to a statistical analysis which yields a new response time calculation. Consequently, sensor response time can be estimated from the database, without performing any further noise analysis. (author)

1996-01-01

284

High responsivity, fast ultraviolet photodetector fabricated from ZnO nanoparticle-graphene core-shell structures.  

UK PubMed Central (United Kingdom)

We report a simple, efficient and versatile method for assembling metal oxide nanomaterial-graphene core-shell structures. An ultraviolet photodetector fabricated from the ZnO nanoparticle-graphene core-shell structures showed high responsivity and fast transient response, which are attributed to the improved carrier transport efficiency arising from graphene encapsulation.

Shao D; Yu M; Sun H; Hu T; Lian J; Sawyer S

2013-05-01

285

High responsivity, fast ultraviolet photodetector fabricated from ZnO nanoparticle-graphene core-shell structures  

Science.gov (United States)

We report a simple, efficient and versatile method for assembling metal oxide nanomaterial-graphene core-shell structures. An ultraviolet photodetector fabricated from the ZnO nanoparticle-graphene core-shell structures showed high responsivity and fast transient response, which are attributed to the improved carrier transport efficiency arising from graphene encapsulation.

Shao, Dali; Yu, Mingpeng; Sun, Hongtao; Hu, Tao; Lian, Jie; Sawyer, Shayla

2013-04-01

286

Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake  

DEFF Research Database (Denmark)

Skeletal muscle gene response to exercise depends on nutritional status during and after exercise, but it is unknown whether muscle adaptations to endurance training are affected by nutritional status during training sessions. Therefore, this study investigated the effect of an endurance training program (6 wk, 3 day/wk, 1-2 h, 75% of peak Vo(2)) in moderately active males. They trained in the fasted (F; n = 10) or carbohydrate-fed state (CHO; n = 10) while receiving a standardized diet [65 percent of total energy intake (En) from carbohydrates, 20%En fat, 15%En protein]. Before and after the training period, substrate use during a 2-h exercise bout was determined. During these experimental sessions, all subjects were in a fed condition and received extra carbohydrates (1 g.kg body wt(-1) .h(-1)). Peak Vo(2) (+7%), succinate dehydrogenase activity, GLUT4, and hexokinase II content were similarly increased between F and CHO. Fatty acid binding protein (FABPm) content increased significantly in F (P = 0.007). Intramyocellular triglyceride content (IMCL) remained unchanged in both groups. After training, pre-exercise glycogen content was higher in CHO (545 +/- 19 mmol/kg dry wt; P = 0.02), but not in F (434 +/- 32 mmol/kg dry wt; P = 0.23). For a given initial glycogen content, F blunted exercise-induced glycogen breakdown when compared with CHO (P = 0.04). Neither IMCL breakdown (P = 0.23) nor fat oxidation rates during exercise were altered by training. Thus short-term training elicits similar adaptations in peak Vo(2) whether carried out in the fasted or carbohydrate-fed state. Although there was a decrease in exercise-induced glycogen breakdown and an increase in proteins involved in fat handling after fasting training, fat oxidation during exercise with carbohydrate intake was not changed.

De Bock, K; Derave, W

2008-01-01

287

Time resolved mass flow measurements for a fast gas delivery system  

International Nuclear Information System (INIS)

A technique is demonstrated whereby the delivered mass and flow rate vs. time of a short rise time gas delivery system may be accurately determined. The gas mass M which flows past a point in a gas delivery system by an arbitrary time t may be accurately measured if that point is sealed off within a time interval short compared to the mass flow time scale. If the ejected mass is allowed to equilibrate in a known volume after being cut off from its source, a conventional static pressure measurement before and after injection, and application of the ideal gas law suffices. Assuming reproducibility, a time history M(t) may be generated, allowing the flow rate vs. time dM(t)/dt to be determined. Mass flow measurements are presented for a fast delivery system in which the flow of argon through a 3.2 mm I.D., 0.76 mm thick copper tube is cut off by imploding (? pinching) the tube using a single turn tungsten magnetic field coil. Pinch discharge parameters are 44 ?f, 20 kV, 47 nH, 3.5 m?, 584 kA, and 8.63 ps current period. Optical measurements of the tube's internal area vs. time indicate that the tube is sealed 2 ps from the time the tube is still 90% open (7 ?s from the start of pinch current). The pinch delay is varied from 500--1,500 ps from the valve trigger (0--1,000 ps from the start of gas flow). The mass injected into the test volume is ? 100 ?g during this interval. The leak rate of the sealed tube results in a mass increase of only ? 0.1 ?g by the time the pressure gauge stabilizes (6 s). Results are correlated with piezoelectric probe measurements of the gas flow and 2-D axisymmetric numerical simulations of the ? pinch process. Simulations of a ? pinch suitable for characterizing an annular supersonic nozzle typical of those used in gas puff z pinches are discussed.

1992-01-01

288

Effect of time of day and fasting duration on measures of glycaemia: analysis from the Whitehall II Study.  

UK PubMed Central (United Kingdom)

AIMS/HYPOTHESIS: We aimed to study diurnal variation in glucose regulation by examining the effects of time of day and fasting duration on fasting plasma glucose (FPG), 2 h post-load plasma glucose (2hPG) and HbA(1c) levels. METHODS: We analysed data from 5,978 non-diabetic white men and women from the prospective Whitehall II Study. All studied participants fasted for at least 8 h before a clinical examination, which included an OGTT and anthropometric measurements. We fitted mixed-effects models for FPG, 2hPG and HbA(1c) as outcome variables, and time of day and/or fasting duration as explanatory variables. Models were adjusted for age, BMI and study phase. RESULTS: Time of day and fasting duration were associated inversely with FPG and positively with 2hPG. The mean difference between measures at 08:00 and 15:00 hours in men/women was -0.46 (95% CI -0.50, -0.42) mmol/l/-0.39 (95% CI -0.46, -0.31) mmol/l and 1.39 (95% CI 1.25, 1.52) mmol/l/1.19 (95% CI 0.96, 1.42) mmol/l for FPG and 2hPG, respectively. HbA(1c) levels were independent of either time. Time of day and fasting duration were independently associated with 2hPG. In contrast, the effect of fasting duration on FPG was markedly attenuated with adjustment for time of day. Ageing, but not obesity, was associated with increased diurnal variation in glucose tolerance. CONCLUSIONS/INTERPRETATION: Both time of day and fasting duration should be considered in clinical practice and epidemiological studies, since they have clinically relevant effects on FPG and 2hPG levels. As biochemically expected, HbA(1c) levels are independent of time of blood sampling and fasting duration.

Hulmán A; Færch K; Vistisen D; Karsai J; Nyári TA; Tabák AG; Brunner EJ; Kivimäki M; Witte DR

2013-02-01

289

Fast nonlinear optical response from proton-bombarded multiple quantum well structures  

Energy Technology Data Exchange (ETDEWEB)

Proton bombardment is shown to shorten the recovery time of the excitonic absorption in GaAs/GaAlAs multiple quantum well saturable absorbers. The response time can be reduced from 30 ns to 150 ps without affecting the absorption characteristics or the saturation energy.

Silberberg, Y.; Smith, P.W.; Miller, D.A.B.; Tell, B.; Gossard, A.C.; Wiegmann, W.

1985-04-15

290

Fast nonlinear optical response from proton-bombarded multiple quantum well structures  

International Nuclear Information System (INIS)

Proton bombardment is shown to shorten the recovery time of the excitonic absorption in GaAs/GaAlAs multiple quantum well saturable absorbers. The response time can be reduced from 30 ns to 150 ps without affecting the absorption characteristics or the saturation energy

1985-04-15

291

Temporal response and real time measurements with 5GHz photocell-oscilloscope system at low light levels  

International Nuclear Information System (INIS)

Experiments were carried out to investigate by means of picosecond mode-locked laser pulses the performance of fast vacuum photoelectric cells associated with a high sensitivity and high speed cathode-ray tube provided with a channel plate electron multiplier. With an amplitude sensitivity of 140mV/cm an overall time of response of less than 100 ps was measured

1975-01-01

292

Design and development of a fast-response ionization gauge controller  

Energy Technology Data Exchange (ETDEWEB)

Fast pressure measurements in the divertor and pump limiter chambers used in magnetic confinement fusion experiments require a system that can respond to a broad range of pressures while maintaining good noise immunity. Available designs of gauge controllers were unable to provide a acceptable noise immunity. A fast ionization gauge controller that can respond to pressure changes in the range from 1 {times} 10{sup {minus}1} to 2 {times} 10{sup {minus}5} Torr in less than 10 ms using a Schultz-Phelps gauge assembly has been developed. The Schultz-Phelps gauge provides full coverage of the desired pressure range and is less susceptible to magnetic field interference than other available types of ionization gauges. The gauge controller as designed provides simultaneous readout of three decades of pressure. Major design concerns have been to minimize noise induced by the gauge tube filament drive and noise pickup by the ionization current electrometer. By using DC filament drive, a major shortcoming of available gauge controllers, i.e., 60-Hz pickup caused by filament modulation of the electron current, has been overcome. Second, by locating the electrometer amplifier as close to the Schultz-Phelps gauge as possible, cable-induced noise pickup has been reduced to an acceptable level. Problems encountered in the design and test of the gauge controller and future improvements are discussed. 3 refs., 4 figs.

Halliwell, J.W.; Dyer, G.R.; Simpkins, J.E (Oak Ridge National Lab., TN (USA))

1989-01-01

293

Model for Predicting End User Web Page Response Time  

CERN Multimedia

Perceived responsiveness of a web page is one of the most important and least understood metrics of web page design, and is critical for attracting and maintaining a large audience. Web pages can be designed to meet performance SLAs early in the product lifecycle if there is a way to predict the apparent responsiveness of a particular page layout. Response time of a web page is largely influenced by page layout and various network characteristics. Since the network characteristics vary widely from country to country, accurately modeling and predicting the perceived responsiveness of a web page from the end user's perspective has traditionally proven very difficult. We propose a model for predicting end user web page response time based on web page, network, browser download and browser rendering characteristics. We start by understanding the key parameters that affect perceived response time. We then model each of these parameters individually using experimental tests and statistical techniques. Finally, we d...

Nagarajan, Sathya Narayanan

2012-01-01

294

Analytical study of the pressure sensor response times  

International Nuclear Information System (INIS)

[en] The pressure sensor response times are required by the Nuclear Authority. The response time limits are indicated in the technical specifications. Nowadays, noise analysis techniques are used for the response time calculation. These are more advantageous than the step response classic method. The knowledge of the sensor dynamics is necessary for a correct interpretation of the noise analysis results. The rosemount capacitive pressure sensor dynamics is well explained by a real pole due to the sensor inner structure and a conjugate complex pole pair, depending on sensing line. Deterministic experiences in laboratory confirm the validity of the dynamic model and show us the interesting frequency range. The real pole contribution in the response time is dominant. However it exists a small complex pole dependency. (Author) 9 refs

1997-01-01

295

Fast-timing measurements performed at ALTO on 137,139Cs  

International Nuclear Information System (INIS)

Fast-timing measurements were performed on 137,139Cs obtained from the ?- decay of 137'139Xe. The neutron-rich Xe nuclei were produced by the 238U photofission induced by the 50 MeV electron beam delivered by the ALTO facility. The half-lives of the first excited state in 137Cs and of six excited states in 139Cs were measured for the first time. These T1/2 results give new information on the structure of the 137,13955Cs82,84 nuclei located near the neutron closed shell N = 82. In particular, it is shown that, in both nuclei, the first excited 5/2+ level corresponds mainly to the one-proton state issued from the ?2d5/2 orbital. From the comparison with other N = 84 isotones, the most probable spin values for the states located at 289.8, 393.5, and 393.8 keV in 139Cs appear to be 5/2+, 3/2+, and 1/2+.

2012-05-28

296

The effect of time-of-day and Ramadan fasting on anaerobic performances.  

UK PubMed Central (United Kingdom)

This study was designed to assess the effects of Ramadan-intermittent-fasting (RIF) and time-of-day on muscle power and fatigue during the Wingate test. In a randomized design, 10 football players completed a Wingate test at 07:00 and 17:00?h on 3 different occasions: one week before Ramadan (BR), the second week of Ramadan (SWR) and the fourth week of Ramadan (ER). There was an interval of 36-h between any 2 successive tests. During the Wingate test, peak power (PP), mean power (MP) and the fatigue index (FI) were recorded. While PP, MP and FI were greater in the evening than in the morning during BR (p<0.001), these diurnal variations in muscle power disappeared during the month of Ramadan (i.?e., SWR and ER) due to a significant decrease in PP and MP in the evening (p<0.001). However, the diurnal variation in FI when measured at 17:00?h increased during this month (p<0.001). In addition, ratings of perceived exertion and fatigue were higher in the evening during Ramadan in comparison with BR. These results suggest that Ramadan might modify the circadian rhythm of muscle power and fatigue during the Wingate test by decreasing power output and increasing muscle fatigue at the time of the acrophase.

Chtourou H; Hammouda O; Chaouachi A; Chamari K; Souissi N

2012-02-01

297

Fast Inversion Method for Determination of Planetary Parameters from Transit Timing Variations  

Science.gov (United States)

The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Non-transiting planets in the system can be inferred from TTVs by their gravitational interaction with the transiting planet. The TTV method is sensitive to low-mass companions and can be used to validate planetary candidates from Kepler. We developed a fast algorithm that can be used to determine the mass and orbit of planets from TTVs. We applied our code, known as TTVIM, to a wide variety of planetary systems to test the uniqueness of the TTV inversion problem, and its dependence on S/N of TTV measurements. We found that planetary parameters, including the mass and mutual orbital inclination of planets, can be determined for most systems where the amplitude of short-period TTVs exceeds noise. In principle, the TTV method can therefore be used to characterize the inclination distribution of multi-planet systems. We are applying the code to the available Kepler data and will discuss the interesting systems at the meeting. This research was supported by the NSF Award AST 1008890.

Nesvorny, David; Beauge, C.

2011-09-01

298

FAST INVERSION METHOD FOR DETERMINATION OF PLANETARY PARAMETERS FROM TRANSIT TIMING VARIATIONS  

International Nuclear Information System (INIS)

[en] The transit timing variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Non-transiting planets in the system can be inferred from TTVs by their gravitational interaction with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Here we describe a fast algorithm that can be used to determine the mass and orbit of the non-transiting planets from the TTV data. We apply our code, ttvim.f, to a wide variety of planetary systems to test the uniqueness of the TTV inversion problem and its dependence on the precision of TTV observations. We find that planetary parameters, including the mass and mutual orbital inclination of planets, can be determined from the TTV data sets that should become available in near future. Unlike the radial velocity technique, the TTV method can therefore be used to characterize the inclination distribution of multi-planet systems.

2010-01-20

299

High time resolution electron measurement by Fast Electron energy Spectrum Analyzer (FESA)  

International Nuclear Information System (INIS)

[en] We have newly developed an electron energy analyzer FESA (Fast Electron energy Spectrum Analyzer) for a future magnetospheric satellite mission SCOPE. The SCOPE mission is designed in order that observational studies from the cross-scale coupling viewpoint are enabled. One of the key observations necessary for the SCOPE mission is high-time resolution electron measurement. Eight FESAs on a spinning spacecraft are capable of measuring three dimensional electron distribution function with time resolution of 8 msec. FESA consists of two electrostatic analyzers that are composed of three nested hemispherical deflectors. Single FESA functions as four top-hat type electrostatic analyzers that can measure electrons with four different energies simultaneously. By measuring the characteristics of the test model FESA, we proved the validity of the design concept of FESA. Based on the measured characteristics, we designed FESA optimized for the SCOPE mission. This optimized analyzer has good enough performance to measure three dimensional electron distribution functions around the magnetic reconnection region in the Earth's magnetotail.

2009-06-16

300

Parvalbumin tunes spike-timing and efferent short-term plasticity in striatal fast spiking interneurons.  

Science.gov (United States)

? Striatal fast spiking interneurons (FSIs) modulate output of the striatum by synchronizing medium-sized spiny neurons (MSNs). Recent studies have broadened our understanding of FSIs, showing that they are implicated in severe motor disorders such as parkinsonism, dystonia and Tourette syndrome. FSIs are the only striatal neurons to express the calcium-binding protein parvalbumin (PV). This selective expression of PV raises questions about the functional role of this Ca(2+) buffer in controlling FSI Ca(2+) dynamics and, consequently, FSI spiking mode and neurotransmission. To study the functional involvement of FSIs in striatal microcircuit activity and the role of PV in FSI function, we performed perforated patch recordings on enhanced green fluorescent protein-expressing FSIs in brain slices from control and PV-/- mice. Our results revealed that PV-/- FSIs fired more regularly and were more excitable than control FSIs by a mechanism in which Ca(2+) buffering is linked to spiking activity as a result of the activation of small conductance Ca(2+)-dependent K(+) channels. A modelling approach of striatal FSIs supports our experimental results. Furthermore, PV deletion modified frequency-specific short-term plasticity at inhibitory FSI to MSN synapses. Our results therefore reinforce the hypothesis that in FSIs, PV is crucial for fine-tuning of the temporal responses of the FSI network and for the orchestration of MSN populations. This, in turn, may play a direct role in the generation and pathology-related worsening of motor rhythms. PMID:23551945

Orduz, David; Bischop, Don Patrick; Schwaller, Beat; Schiffmann, Serge N; Gall, David

2013-04-03

 
 
 
 
301

Parvalbumin tunes spike-timing and efferent short-term plasticity in striatal fast spiking interneurons.  

UK PubMed Central (United Kingdom)

? Striatal fast spiking interneurons (FSIs) modulate output of the striatum by synchronizing medium-sized spiny neurons (MSNs). Recent studies have broadened our understanding of FSIs, showing that they are implicated in severe motor disorders such as parkinsonism, dystonia and Tourette syndrome. FSIs are the only striatal neurons to express the calcium-binding protein parvalbumin (PV). This selective expression of PV raises questions about the functional role of this Ca(2+) buffer in controlling FSI Ca(2+) dynamics and, consequently, FSI spiking mode and neurotransmission. To study the functional involvement of FSIs in striatal microcircuit activity and the role of PV in FSI function, we performed perforated patch recordings on enhanced green fluorescent protein-expressing FSIs in brain slices from control and PV-/- mice. Our results revealed that PV-/- FSIs fired more regularly and were more excitable than control FSIs by a mechanism in which Ca(2+) buffering is linked to spiking activity as a result of the activation of small conductance Ca(2+)-dependent K(+) channels. A modelling approach of striatal FSIs supports our experimental results. Furthermore, PV deletion modified frequency-specific short-term plasticity at inhibitory FSI to MSN synapses. Our results therefore reinforce the hypothesis that in FSIs, PV is crucial for fine-tuning of the temporal responses of the FSI network and for the orchestration of MSN populations. This, in turn, may play a direct role in the generation and pathology-related worsening of motor rhythms.

Orduz D; Bischop DP; Schwaller B; Schiffmann SN; Gall D

2013-07-01

302

Fast response neutron emission monitor for fusion reactor using stilbene scintillator and Flash-ADC.  

UK PubMed Central (United Kingdom)

The stilbene neutron detector which has been used for neutron emission profile monitoring in JT-60U has been improved, to respond to the requirement to observe the high-frequency phenomena in megahertz region such as toroidicity-induced Alfvén Eigen mode in burning plasma as well as the spatial profile and the energy spectrum. This high-frequency phenomenon is of great interest and one of the key issues in plasma physics in recent years. To achieve a fast response in the stilbene detector, a Flash-ADC is applied and the wave form of the anode signal stored directly, and neutron/gamma discrimination was carried out via software with a new scheme for data acquisition mode to extend the count rate limit to MHz region from 1.3 x 10(5) neutron/s in the past, and confirmed the adequacy of the method.

Itoga T; Ishikawa M; Baba M; Okuji T; Oishi T; Nakhostin M; Nishitani T

2007-01-01

303

Kinematic factors affecting fast and slow straight and change-of-direction acceleration times.  

UK PubMed Central (United Kingdom)

In many sports, players are often required to accelerate immediately after rapid changes of direction (CODs) before performing a subsequent COD movement. Therefore, court-based players will often not attain their maximum velocity before having to decelerate and change direction. The purpose of this study was to determine what kinematic factors affected fast and slow straight acceleration (SA) and change-of-direction acceleration (CODA) times. National under-21 netball players performed 3 trials each of a 2.5-m SA and a CODA involving a 180° COD followed immediately by a 2.5-m sprint. Players were grouped into either a faster or slower category based on performance times (2.5-m time). Significantly higher average step frequency (4%, p = 0.03) was observed for the faster group when compared with the slower group in the CODA task. For the SA task, faster times were associated with significantly smaller average step lengths (SLs; 7%, p = 0.03), greater torso angles (i.e., greater forward lean; 30-37%, p < 0.001), and smaller hip angle (less knee lift) in the first step (21-22%, p = 0.00). The SA task was associated with significantly longer average SLs (21-23%, p = 0.00) and significantly longer SL across all 3 steps as compared with the CODA task (17-27%, p < 0.001) A significantly increased forward lean was associated with the first step of the SA task (34%, p < 0.001) and significantly higher knee lift for the first and second steps of the SA task (11-22%, p = 0.00 and 0.04, respectively). These kinematic differences can be used for training purposes for both coaches and strength and conditioning practitioners.

Hewit JK; Cronin JB; Hume PA

2013-01-01

304

Objective assessment of drowsiness and reaction time during intermittent Ramadan fasting in young men: a case-crossover study.  

UK PubMed Central (United Kingdom)

BACKGROUND: Ramadan fasting and its attendant lifestyle changes induce changes in the circadian rhythm and in associated physiological and metabolic functions. Previous studies that have assessed psychomotor performance during Ramadan fasting have reported conflicting results. Therefore, we designed this study to objectively assess the effects of intermittent fasting during and outside Ramadan (to control for lifestyle changes) on drowsiness, blink total duration and mean reaction time (MRT) test while controlling for potential confounders. METHODS: Eight healthy volunteers with a mean age of 25.3 ± 2.9 years and a mean body mass index (BMI) of 23.4 ± 3.2 kg/m2 reported to the sleep laboratory on four occasions for polysomnography (PSG) and drowsiness and psychomotor assessments as follows: 1) adaptation; 2) 4 weeks before Ramadan while performing the Islamic fasting for 1 week (baseline fasting) (BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting (Ramadan). OPTALERT™ was used to objectively assess daytime drowsiness using the Johns Drowsiness Scale (JDS), and blink total duration and a visual reaction time test were used to assess MRT. RESULTS: Rapid eye movement (REM) sleep percentage was significantly lower at BLF (17.7 ± 8.1%) and at Ramadan (18.6 ± 10.7%) compared with BL (25.6 ± 4.8%) (p?fasting has no impact on drowsiness and vigilance as measured by the JDS, total blink duration and MRT.

Bahammam AS; Nashwan S; Hammad O; Sharif MM; Pandi-Perumal SR

2013-01-01

305

Time-delayed summation as a means of improving resolution on fast rotating computed tomography systems.  

UK PubMed Central (United Kingdom)

PURPOSE: Modern computed tomography (CT) systems are supporting increasingly fast rotation speeds, which are a prerequisite for fast dynamic acquisition, e.g. in perfusion imaging, and for new modalities such as dedicated breast CT, where breathhold scanning is indicated. However, not all detector technologies are supporting the high frame rates that are necessary to retain high resolution for objects far away from the isocenter. Even on systems that would support a sufficiently high frame rate, the necessary bandwidth of the data transfer from the rotating gantry stills remains challenging. The authors evaluated a pixel shifting technique termed time-delayed summation (TDS) as a method of increasing resolution on fast rotating CT systems without the need to increase the frame rate. METHODS: In TDS mode, detector pixel values are shifted along rows during image acquisition to compensate for detector motion. In order to fully exploit TDS, focal spot position control (FSC) was used in combination with TDS. FSC applies a counter movement to the x-ray focal spot during image acquisition such that it is kept fixed in space. As a proof of concept, measurements were performed on a prototype photon counting detector capable of TDS. The detector was mounted on a movable table and a gold wire phantom was imaged with different TDS settings and detector velocities. Additionally, simulations of a broad range of TDS and FSC settings on two different modalities, a clinical CT scanner and a breast CT scanner, and two different detector geometries, flat and cylindrical, were performed to assess the gain in resolution and contrast in cylindrical water phantoms containing a small wire at distances from the phantom center varied from 5% to 90% of the phantom radius. As figures of merit, the modulation transfer function (MTF) at 10% and the maximum contrast were used and compared against the respective values when using step-and-shoot acquisition, which means stopping the rotation when a projection image is acquired. RESULTS: Measurements showed that detector movement and the resulting blurring of the wire projections were compensated to the expected degree when using the appropriate number of TDS shifts per frame (TDS factor). Using simulations it was found that when using the optimal TDS factor, over 90% of the resolution achieved in step-and-shot mode was reached for all investigated wire positions. TDS showed better performance on a cylindrical detector that on the same system with a flat detector. TDS factors that were deviating from the optimum by more than 1 shift led to a performance below that of standard continuous acquisition. CONCLUSIONS: The findings of this study encourage the combined usage of TDS and FSC in systems that require fast rotation. The integration of TDS in state-of-the-art x-ray detectors is feasible.

Nowak T; Hupfer M; Althoff F; Brauweiler R; Eisa F; Steiding C; Kalender WA

2012-04-01

306

A fast-response production-inventory model for deteriorating seasonal products with learning in set-ups  

Directory of Open Access Journals (Sweden)

Full Text Available The classical production-inventory model assumes that both demand and set-up costs are constant. However, in real manufacturing environment, managers usually embark on continuous improvement programmes that often lead to more effective use of tools and machineries and consequently reduction in set-up costs. In fact, constant emphasis on reduction of set-up costs is usually cited as one of the factors responsible for the efficiency of Japanese manufacturing methods. On the other hand, the demand for seasonal product is often characterized by a mixture of time-dependent patterns over the entire season. This paper investigates the effect of learning-based reduction in set-up costs on the optimal schedules and costs of a production-inventory system for deteriorating seasonal products. The demand pattern is a general three-phase ramp-type demand function that represents the various phases of demand commonly observed in many seasonal products in the market. A two-parameter Weibull-distribution function is used for the deterioration of items in order to make the model more generalized and realistic. The study further presents two different multi-period production strategies that can ensure a fast-response to customers’ demand and compare them with the usual single period strategy. The Numerical example and sensitivity analysis shows that learning-based reduction in set-up costs leads to higher production frequency and shorter production runs which are vital aspects of the just-in-time (JIT) philosophy.

Ibraheem Abdul; Atsuo Murata

2011-01-01

307

Modeling of the Response Time of Thermal Flow Sensors  

Directory of Open Access Journals (Sweden)

Full Text Available This paper introduces a simple theoretical model for the response time of thermal flow sensors. Response time is defined here as the time needed by the sensor output signal to reach 63.2% of amplitude due to a change of fluid flow. This model uses the finite-difference method to solve the heat transfer equations, taking into consideration the transient conduction and convection between the sensor membrane and the surrounding fluid. Program results agree with experimental measurements and explain the response time dependence on the velocity and the sensor geometry. Values of the response time vary from about 5 ms in the case of stagnant flow to 1.5 ms for a flow velocity of 44 m/s.

Safir Issa; Hannes Sturm; Walter Lang

2011-01-01

308

Multifractal analyses of response time series: A comparative study.  

UK PubMed Central (United Kingdom)

Response time series with a non-Gaussian distribution and long-range dependent dynamics have been reported for several cognitive tasks. Conventional monofractal analyses numerically define a long-range dependency as a single scaling exponent, but they assume that the response times are Gaussian distributed. Ihlen and Vereijken (Journal of Experimental Psychology: General, 139, 436-463, 2010) suggested multifractal extensions of the conventional monofractal analyses that are more suitable when the response time has a non-Gaussian distribution. Multifractal analyses estimate a multifractal spectrum of scaling exponents that contain the single exponent estimated by the conventional monofractal analyses. However, a comparison of the performance of multifractal analyses with behavioral variables has not yet been addressed. The present study compares the performance of seven multifractal analyses. The multifractal analyses were tested on multiplicative cascading noise that generates time series with a predefined multifractal spectrum and with a structure of variation that mimics intermittent response time variation. Time series with 1,024 and 4,096 samples were generated with additive noise and multiharmonic trends of two different magnitudes (signal-to-noise/trend ratio; 0.33 and 1). The results indicate that all multifractal analysis has individual pros and cons related to sample size, multifractality, and the presence of additive noise and trends in the response time series. The summary of pros and cons of the seven multifractal analyses provides a guideline for the choice of multifractal analyses of response time series and other behavioral variables.

Ihlen EA

2013-03-01

309

Proposal for a fast, zero suppressing circuit for the digitization of analog pulses over long memory times  

International Nuclear Information System (INIS)

This report describes the design principles of a fast (100 MHz) time and pulse height digitizer that can record up to 15 analog pulses over 10-80 ?s memory times. Unlike other triggered circuits prepulse samples are recorded without the help of an analog delay line. The low power requirements of the circuit as well as its fast read-out characteristics make it very attractive for detectors with many digitizing channels. Conventional circuits are described as a reference for the evaluation of this new design. An ECL 10 K implementation of the circuit is presented in the third section. (orig.)

1984-01-01

310

Planck 2013 results. VII. HFI time response and beams  

CERN Multimedia

This paper characterizes the effective beams, the effective beam window functions (EBWF) and the associated errors for the Planck High Frequency Instrument (HFI) detectors. The effective beam is the angular response including the effect of the optics, detectors, data processing and the scan strategy. The EBWF is the representation of this beam in the harmonic domain that is required to recover an unbiased measurement of the Cosmic Microwave Background (CMB) angular power spectrum. The HFI is a scanning instrument and its effective beams are the convolution of the optical response of the telescope and feeds, the processing of the time-ordered data and deconvolution of the bolometric and electronic time response, and the merging of several surveys to produce maps. The time response transfer functions are measured with observations of Jupiter and Saturn and by minimizing survey difference residuals. The scanning beam is the post-deconvolution angular response of the instrument, and is characterized with observat...

Ade, P A R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bond, J R; Borrill, J; Bouchet, F R; Bowyer, J W; Bridges, M; Bucher, M; Burigana, C; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chary, R -R; Chiang, L -Y; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dunkley, J; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Haissinski, J; Hansen, F K; Hanson, D; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hou, Z; Hovest, W; Huffenberger, K M; Jaffe, T R; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leonardi, R; Leroy, C; Lesgourgues, J; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; MacTavish, C J; Maffei, B; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Matsumura, T; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polegre, A M; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rowan-Robinson, M; Rusholme, B; Sandri, M; Santos, D; Sauvé, A; Savini, G; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Yvon, D; Zacchei, A; Zonca, A

2013-01-01

311

Elements for Response Time Statistics in ERP Transaction Systems  

CERN Multimedia

We present some measurements and ideas for response time statistics in ERP systems. It is shown that the response time distribution of a given transaction in a given system is generically a log-normal distribution or, in some situations, a sum of two or more log-normal distributions. We present some arguments for this form of the distribution based on heuristic rules for response times, and we show data from performance measurements in actual systems to support the log-normal form. Deviations of the log-normal form can often be traced back to performance problems in the system. Consequences for the interpretation of response time data and for service level agreements are discussed.

Mielke, A

2004-01-01

312

Considerations for human exposure standards for fast-rise-time high-peak-power electromagnetic pulses.  

UK PubMed Central (United Kingdom)

Development of new emitter systems capable of producing high-peak-power electromagnetic pulses with very fast rise times and narrow pulse widths is continuing. Such directed energy weapons systems will be used in the future to defeat electronically vulnerable targets. Human exposures to these pulses can be expected during testing and operations. Development of these technologies for radar and communications purposes has the potential for wider environmental exposure, as well. Current IEEE C95.1-1991 human exposure guidelines do not specifically address these types of pulses, though limits are stated for pulsed emissions. The process for developing standards includes an evaluation of the relevant bioeffects data base. A recommendation has been made that human exposure to ultrashort electromagnetic pulses that engender electromagnetic transients, called precursor waves, should be avoided. Studies that purport to show the potential for tissue damage induced by such pulses were described. The studies cited in support of the recommendation were not relevant to the issues of tissue damage by propagated pulses. A number of investigations are cited in this review that directly address the biological effects of electromagnetic pulses. These studies have not shown evidence of tissue damage as a result of exposure to high-peak-power pulsed microwaves. It is our opinion that the current guidelines are sufficiently protective for human exposure to these pulses.

Merritt JH; Kiel JL; Hurt WD

1995-06-01

313

A 200 kV fast rise time, low jitter, trigger system with magnetic pulse sharpener  

Energy Technology Data Exchange (ETDEWEB)

The DARHT Facility is being designed at Los Alamos National Laboratory to produce high resolution flash radiographs of hydrodynamic experiments. Two linear induction accelerators (LIA), each in the range of 16 to 20 MeV, will be used to produce intense bremsstrahlung X-ray pulses of short duration (60 ns flat top). Each LIA will produce a 3 kA, high brightness, electron beam using a 4 MeV injector and a series of 250 kV induction cells. Technology demonstration of key accelerator subsystems is under progress at the DARHT Integrated Test Stand (ITS). The eight inductions cells present in the ITS are driven by a Maxwell prototype Induction Cell Pulsed Power Supply (ICPPS) which provides 250 kV, 70ns pulses via four Blumleins. Each Blumlein drives two cells and is triggered using independently controlled trigger units. This turnkey DARHT Trigger System, consisting of four separate trigger units, provides 200 kV trigger pulses with low jitter and fast rise time to each of the four Blumlein coaxial spark gaps. Details of the trigger system design and results obtained during extensive testing at Maxwell are described.

Jaitly, N.C.; Ramrus, A. [Maxwell Labs., Inc., San Diego, CA (United States); Coleman, M.D. [Directed Technologies, Inc., San Diego, CA (United States); Earley, L.M.; Downing, J.N.; Reisch, H.H.; Caudill, L.D.; Eversol, S.A. [Los Alamos National Lab., NM (United States)

1993-12-31

314

Experience with RTD response time testing in nuclear power plants  

International Nuclear Information System (INIS)

The reactor coolant temperatures in pressurized water reactors are measured with platinum resistance temperature detectors (RTDs). The information furnished by these RTDs is used for plant protection as well as control. As a part of the plant protection system, the RTDs must respond to temperature changes in a timely fashion. The RTD response time requirements are different for the various plant types. These requirements are specified in the plant technical specifications in terms of an RTd time constant. The current time constant requirements for nuclear plant RTDs varies from 0.5 seconds to 13.0 seconds depending on the type of the plant. Therefore, different types of RTDs are used in different plants to achieve the required time constants. In addition, in-situ response time tests are periodically performed on protective system RTDs to ensure that the in-service time constants are within acceptable limits as the plant is operating. The periodic testing is important because response time degradation may occur while the RTD ages in the process. Recent response time tests in operating plants revealed unacceptable time constants for several protection system RTDs. As a result, these plants had to be shut down to resolve the problem which in one case was due to improper installation and in another case was because of degradation of a thermal compound used in the thermowell.

1985-01-01

315

Influence of a fed or fasted state on the s-IgA response to prolonged cycling in active men and women.  

Science.gov (United States)

This study investigated the effect of a fed or fasted state on the salivary immunoglobulin A (s-IgA) response to prolonged cycling. Using a randomized, crossover design, 16 active adults (8 men and 8 women) performed 2 hr of cycling on a stationary ergometer at 65% of maximal oxygen uptake on 1 occasion after an overnight fast (FAST) and on another occasion 2 hr after consuming a 2.2-MJ high-carbohydrate meal (FED). Timed, unstimulated whole saliva samples were collected immediately before ingestion of the meal, immediately preexercise, 5 min before cessation of exercise, immediately postexercise, and 1 hr postexercise. The samples were analyzed for s-IgA concentration, osmolality, and cortisol, and saliva flow rates were determined to calculate s-IgA secretion rate. Saliva flow rate decreased by 50% during exercise (p < .05), and s-IgA concentration increased by 42% (p < .05), but s-IgA secretion rate remained unchanged. There was a 37% reduction in s-IgA:osmolality postexercise (p < .05), and salivary cortisol increased by 68% (p < .05). There was no effect of FED vs. FAST on these salivary responses. The s-IgA concentration, secretion rate, and osmolality were found to be significantly lower in women than in men throughout the exercise protocol (p < .05); however, there was no difference between genders in saliva flow rate, s-IgA:osmolality ratio, or cortisol. These data demonstrate that a fed or fasted state 2 hr before exercise does not influence resting s-IgA or the response to prolonged cycling. Furthermore, these results show lower levels of s-IgA and osmolality in women than in men at rest. PMID:19574610

Allgrove, Judith E; Geneen, Louise; Latif, Sarah; Gleeson, Michael

2009-06-01

316

Influence of a fed or fasted state on the s-IgA response to prolonged cycling in active men and women.  

UK PubMed Central (United Kingdom)

This study investigated the effect of a fed or fasted state on the salivary immunoglobulin A (s-IgA) response to prolonged cycling. Using a randomized, crossover design, 16 active adults (8 men and 8 women) performed 2 hr of cycling on a stationary ergometer at 65% of maximal oxygen uptake on 1 occasion after an overnight fast (FAST) and on another occasion 2 hr after consuming a 2.2-MJ high-carbohydrate meal (FED). Timed, unstimulated whole saliva samples were collected immediately before ingestion of the meal, immediately preexercise, 5 min before cessation of exercise, immediately postexercise, and 1 hr postexercise. The samples were analyzed for s-IgA concentration, osmolality, and cortisol, and saliva flow rates were determined to calculate s-IgA secretion rate. Saliva flow rate decreased by 50% during exercise (p < .05), and s-IgA concentration increased by 42% (p < .05), but s-IgA secretion rate remained unchanged. There was a 37% reduction in s-IgA:osmolality postexercise (p < .05), and salivary cortisol increased by 68% (p < .05). There was no effect of FED vs. FAST on these salivary responses. The s-IgA concentration, secretion rate, and osmolality were found to be significantly lower in women than in men throughout the exercise protocol (p < .05); however, there was no difference between genders in saliva flow rate, s-IgA:osmolality ratio, or cortisol. These data demonstrate that a fed or fasted state 2 hr before exercise does not influence resting s-IgA or the response to prolonged cycling. Furthermore, these results show lower levels of s-IgA and osmolality in women than in men at rest.

Allgrove JE; Geneen L; Latif S; Gleeson M

2009-06-01

317

Real-time study of fast-electron transport inside dense hot plasmas  

International Nuclear Information System (INIS)

[en] We offer a method to study transport of fast electrons in dense hot media. The technique relies on temporal profiling of the laser induced magnetic fields and offers a unique capability to map the hot electron currents and their neutralization (or lack of it) by the return currents in the plasma. We report direct quantitative measurements of strong electric inhibition in insulators and turbulence induced anomalous stopping of hot electrons in conductors. The present technique can prove extremely important from the point of view of fast ignition scheme, which relies on the penetration of fast electrons into the fusion core

2006-01-01

318

Development of a fast response rotating polarimeter for a faraday rotation measurement  

International Nuclear Information System (INIS)

This paper describes a method for using a spindle sustained with active magnetic bearing to make a rotating half waveplate frequency more fast. The time interval of the zero-cross phase measurement is 189 ?sec in this experiment. The magnetic bearing is applicable to increase the rotating waveplate frequency by a factor of 2-3 compared with the conventional one. The waveplate speed as well as the deviation with respect to the stationary laser beam has no influence on the amplitude and phase shift of the rotating polarized beam signal. There is also no influence of the mirror reflections on the phase shift. The overall phase resolution is estimated to be about 0.1 degrees. (author)

1994-01-01

319

A microprocessor-controlled fast-response speed regulator with dual mode current loop for DCM drives  

Science.gov (United States)

A new control method is described in which a microprocessor is used to regulate the speed of a dc motor driven by antiparallel-connected three-phase dual thyristor converters. A distinct feature of this speed regulating system is that speed response is improved by using a fast-response current controller for the internal loop. A fast-response current controller is obtained by employing a nonlinear compensation subloop and a proportional plus integral compensation subloop. The nonlinear compensation subloop is used to linearize the nonlinear load characteristics of the thyristor converter, which are encountered under discontinuous conduction states of current. The proportional plus integral compensation subloop reduces the deviation of detected current from the current reference. With these two current-control subloops a fast motor speed response is achieved under discontinuous as well as continuous conduction states; hence the steady-state accuracy of speed is improved. A speed regulator using a microprocessor was trial manufactured and tested with a 20-kW dc motor. It was found that an extremely fast controlled current response can be obtained even with a relatively long sampling period. Further, normal action was confirmed in four-quadrant operation.

Ohmae, T.; Matsuda, T.; Suzuki, T.; Azusawa, N.; Kamiyama, K.; Konishi, T.

1980-06-01

320

A fast least-squares arrival time estimator for scintillation pulses  

International Nuclear Information System (INIS)

[en] The true weighted least-squares (WLS) arrival time estimator for scintillation pulse detection was previously found to out-perform conventional arrival time estimators such as leading-edge and constant-fraction timers, but has limited applications because of its complexity. A new diagonalized version of the weighted least-squares (DWLS) estimator has been developed which, like the true WLS, incorporates the statistical properties of the scintillation detector. The new DWLS reduces estimator complexity at the expense of fundamental timing resolution. The advantage of the DWLS implementation is that only scalar multiplications and additions are needed instead of the matrix operations used in the true WLS. It also preserves the true WLS's ability to effectively separate piled-up pulses. The DWLS estimator has been applied to pulses which approximate the response of BGO and NaI(Tl) scintillation detectors. The timing resolution obtained with the DWLS estimator is then compared to conventional analog timers along with the Cramer-Rao lower bound on achievable timing error. The DWLS out-performs the conventional arrival time estimators but does not provide optimal performance compared to the lower bound; however, it is more robust than the true WLS estimator

1993-11-06

 
 
 
 
321

A fast least-squares arrival time estimator for scintillation pulses  

Energy Technology Data Exchange (ETDEWEB)

The true weighted least-squares (WLS) arrival time estimator for scintillation pulse detection was previously found to out-perform conventional arrival time estimators such as leading-edge and constant-fraction timers, but has limited applications because of its complexity. A new diagonalized version of the weighted least-squares (DWLS) estimator has been developed which, like the true WLS, incorporates the statistical properties of the scintillation detector. The new DWLS reduces estimator complexity at the expense of fundamental timing resolution. The advantage of the DWLS implementation is that only scalar multiplications and additions are needed instead of the matrix operations used in the true WLS. It also preserves the true WLS's ability to effectively separate piled-up pulses. The DWLS estimator has been applied to pulses which approximate the response of BGO and NaI(Tl) scintillation detectors. The timing resolution obtained with the DWLS estimator is then compared to conventional analog timers along with the Cramer-Rao lower bound on achievable timing error. The DWLS out-performs the conventional arrival time estimators but does not provide optimal performance compared to the lower bound; however, it is more robust than the true WLS estimator.

Petrick, N.; Hero, A.O. III; Clinthorne, N.H.; Rogers, W.L. (Univ. of Michigan, Ann Arbor, MI (United States))

1994-08-01

322

Creating fast flow channels in paper fluidic devices to control timing of sequential reactions.  

Science.gov (United States)

This paper reports the development of a method to control the flow rate of fluids within paper-based microfluidic analytical devices. We demonstrate that by simply sandwiching paper channels between two flexible films, it is possible to accelerate the flow of water through paper by over 10-fold. The dynamics of this process are such that the height of the liquid is dependent on time to the power of 1/3. This dependence was validated using three different flexible films (with markedly different contact angles) and three different fluids (water and two silicon oils with different viscosities). These covered channels provide a low-cost method for controlling the flow rate of fluid in paper channels, and can be added following printing of reagents to control fluid flow in selected fluidic channels. Using this method, we redesigned a previously published bidirectional lateral flow pesticide sensor to allow more rapid detection of pesticides while eliminating the need to run the assay in two stages. The sensor is fabricated with sol-gel entrapped reagents (indoxyl acetate in a substrate zone and acetylcholinesterase, AChE, in a sensing zone) present in an uncovered "slow" flow channel, with a second, covered "fast" channel used to transport pesticide samples to the sensing region through a simple paper-flap valve. In this manner, pesticides reach the sensing region first to allow preincubation, followed by delivery of the substrate to generate a colorimetric signal. This format results in a uni-directional device that detects the presence of pesticides two times faster than the original bidirectional sensors. PMID:23079674

Jahanshahi-Anbuhi, Sana; Chavan, Puneet; Sicard, Clémence; Leung, Vincent; Hossain, S M Zakir; Pelton, Robert; Brennan, John D; Filipe, Carlos D M

2012-12-01

323

Time response of temperature sensors using neural networks  

International Nuclear Information System (INIS)

In a PWR nuclear power plant, the primary coolant temperature and feedwater temperature are measured using RTDs (Resistance Temperature Detectors). These RTDs typically feed the plant's control and safety systems and must, therefore, be very accurate and have good dynamic performance. The response time of RTDs is characterized by a single parameter called the Plunge Time Constant defined as the time it takes the sensor output to achieve 63.2 percent of its final value after a step change in temperature. Nuclear reactor service conditions are difficult to reproduce in the laboratory, and an in-situ test method called LCSR (Loop Current Step Response) test was developed to measure remotely the response time of RTDs. >From this test, the time constant of the sensor is identified by means of the LCSR transformation that involves the dynamic response modal time constants determination using a nodal heat-transfer model. This calculation is not simple and requires specialized personnel. For this reason an Artificial Neural Network has been developed to predict the time constant of RTD from LCSR test transient. It eliminates the transformations involved in the LCSR application. A series of LCSR tests on RTDs generates the response transients of the sensors, the input data of the networks. Plunge tests are used to determine the time constants of the RTDs, the desired output of the ANN, trained using these sets of input/output data. This methodology was firstly applied to theoretical data simulating 10 RTDs with different time constant values, resulting in an average error of about 0.74 %. Experimental data from three different RTDs was used to predict time constant resulting in a maximum error of 3,34 %. The time constants values predicted from ANN were compared with those obtained from traditional way resulting in an average error of about 18 % and that shows the network is able to predict accurately the sensor time constant. (author)

2010-01-01

324

Research on a Fast Delivery Production System: Just-in-time production system  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we analyzed calling the age to product or service for consumer demand living in the word. We come to a conclusion that speed or time is the key factors for enterpriser for competing intensely. So, the paper proposes JIT system achieve the tasks. Later, we address thoroughly the meaning of Just-in-time production system from speed and time angles and present two goals ultimate goal and the supporting goals implementation successfully. According to goal, this paper analyzed that implementing JIT should be achieved requires and carry out approaches. At last, this paper provided that JIT contribute benefits and causes to problem. Nonetheless, JIT is a robust production system for manufacturer and consumer. Moreover, I believe that it advent and it will be a main stream of a fluid production system for the future. Key words: just-in-time production system; fast delivery; continue quality improvement; manufacturing cells Résumé: Dans cette mémoire, nous analysons la vocation de l’âge à produire ou à servir pour la vie de la demande consommatrice dans le monde. Nous venons à une conclusion que la vitesse ou le temps est les facteurs clés en faveur de l’entrepreneur dans le but de rivaliser profondément. Donc, la mémoire propose le système JIT accomplit les tâches. Ensuite, nous adressons à fond le sens du système producteur JIT de la vitesse et les angles de temps et présentons deux buts, but ultime et l’implémentation des buts soutenant successivement. D’après le but, cette mémoire analyse que l’implémentation JIT doit être accomplie les demandes et exécuter les propositions. Enfin, cette mémoire fournit que le JIT contribue les avantages et les causes au problème. Malgré tout, JIT est un système robuste producteur pour les fabricants et les consommateurs. En plus, je crois qu’il se réalisera et sera un torrent d’un système producteur fluide pour l’avenir. Mots-Clés: Système producteur JIT ; livraison rapide ; amélioration qualitative continuelle; cellule fabricante

Cai-feng LI

2009-01-01

325

A Fast Topological Trigger for Real Time Analysis of Nanosecond Phenomena; Opening the Gamma Ray Window to Our Universe  

Energy Technology Data Exchange (ETDEWEB)

This work was to enable the development of a proof-of-principle nanosecond trigger system that is designed to perform a real time analysis of fast Cherenkov light flashes from air showers. The basic building blocks of the trigger system have been designed and constructed, and a real world system is now operating in the VERITAS experiment.

Krennrich, Frank [Iowa State University

2013-09-24

326

Analytic Calculus of Response Time in Networked Automation Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a novel approach to evaluate the response time in networked automation systems (NAS) that use a client/server protocol. The developments introduced are derived from modeling the entire architecture in the form of timed event graphs (TEGs), as well as from the resulting state repr...

Addad, Boussad; Amari, Saïd; Lesage, Jean-Jacques

327

Response time evaluation in Ethernet-based automation architectures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, a new method to evaluate the response time in switched Ethernet automation architectures is developed. It is based on the modeling of the whole system in the form of timed event graphs and on the resulting state representation in Max-Plus algebra. After the resolution of the state equ...

Addad, Boussad; Amari, Saïd

328

Dose-time-response cumulative multinomial generalized linear model.  

Science.gov (United States)

In toxicological and pharmaceutical experiments, a type of quantal bioassay experiment is designed in which a response, such as mortality, in a group of animals is recorded over time points under different dose levels in the course of the experiment. The application of the typical logit and probit analyses is no longer valid in this situation because it neglects the dependency on time and also the possible interaction of time and dose concentration on the response in the experiment. In this paper, a dose-time-response model is proposed for this type of experiment and a cumulative multinomial generalized linear model that incorporates time and the other experimental conditions as covariates is developed by the theory of maximum likelihood estimation. Both the point estimator and confidence bands for ED50(t), the concentration of a toxicant that will kill 50% of the animals by a specific time, t; as well as LT50(d), the time to 50% mortalities for a specific concentration, d, is then formulated in closed form from the newly proposed dose-time-response model. Finally, the newly proposed model is considered for a real data set to demonstrate the application. PMID:17219762

Chen, D G

2007-01-01

329

Analysis of Shiraz Solar Thermal Power Plant Response Time  

Directory of Open Access Journals (Sweden)

Full Text Available Shiraz pilot solar thermal power plant is the first Iranian solar power plant constructed near the city of Shiraz, Iran. The main purpose of constructing this pilot plant was to acquire the technology of developing parabolic trough solar thermal power plants for future energy production from solar energy. This plant consists of 48 parabolic trough collectors; each one has 25m long and 3.4 m wide. The plant consists of two cycles, oil heat absorbing cycle and steam production cycle. The plant performance and transition period to reach steady state condition or damping some disturbances as well as oil cycle heating and steam generation rate depends on several factors such as oil cycle response time. Response time is a parameter that can be used for efficient control of solar power plant. To study response time, field experimental measurements have been made during the years 2009 to 2010 based on the standard procedure and plant simulation. The experiments include: plant start up, evaluation of oil temperature increase in the field of collectors, solar radiation measurements, temperature and pressure changes in the heat exchangers, weather temperature changes and wind speed and the effect of above changes on the system response time are determined. Two modeling methods (based on the recommended standards) of finding response time are employed. Results show that response time of the oil cycle varies from 150 seconds to 400 seconds by measurements, while by modeling simulation it is about 400-500 seconds. Response time is strongly depends on the environmental conditions such as oil temperture, wind and ambient temperature and specially the oil mass flow rate.

K. Azizian; M. Yaghoubi; I. Niknia; P. Kanan

2013-01-01

330

Tracking the speech signal--time-locked MEG signals during perception of ultra-fast and moderately fast speech in blind and in sighted listeners.  

UK PubMed Central (United Kingdom)

Blind people can learn to understand speech at ultra-high syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. To further elucidate the neural mechanisms underlying this skill, magnetoencephalographic (MEG) measurements during listening to sentence utterances were cross-correlated with time courses derived from the speech signal (envelope, syllable onsets and pitch periodicity) to capture phase-locked MEG components (14 blind, 12 sighted subjects; speech rate=8 or 16 syllables/s, pre-defined source regions: auditory and visual cortex, inferior frontal gyrus). Blind individuals showed stronger phase locking in auditory cortex than sighted controls, and right-hemisphere visual cortex activity correlated with syllable onsets in case of ultra-fast speech. Furthermore, inferior-frontal MEG components time-locked to pitch periodicity displayed opposite lateralization effects in sighted (towards right hemisphere) and blind subjects (left). Thus, ultra-fast speech comprehension in blind individuals appears associated with changes in early signal-related processing mechanisms both within and outside the central-auditory terrain.

Hertrich I; Dietrich S; Ackermann H

2013-01-01

331

Response Time Optimization for Replica Selection Service in Data Grids  

Directory of Open Access Journals (Sweden)

Full Text Available Problem Statement: Data Grid architecture provides a scalable infrastructure for grid services in order to manage data files and their corresponding replicas that were distributed across the globe. The grid services are designed to support a variety of data grid applications (jobs) and projects. Replica selection is a high-level service that chooses a replica location from among many distributed replicas with the minimum response time for the users' jobs. Estimating the response time accurately in the grid environment is not an easy task. The current systems expose high response time in selecting the required replicas because the response time is estimated by considering the data transfer time only. Approach: We proposed a replica selection system that selects the best replica location for the users' running jobs in a minimum response time that can be estimated by considering new factors besides the data transfer time, namely, the storage access latency and the replica requests that waiting in the storage queue. Results: The performance of the proposed system was compared with a similar system that exists in the literature namely, SimpleOptimiser. The simulation results demonstrated that our system performed better than the SimpleOptimiser on an average of 6%. Conclusions: The proposed system can select the best replica location in a lesser response time than the SimpleOptimise. The efficiency of the proposed system is 6% higher than the SimpleOptimise. The efficiency level has a high impact on the quality of service that is perceived by grid users in a data grid environment where the data files are relatively big. For example, the data files produced from the scientific applications are of the size hundreds of Terabytes.

Husni H.E. AL-Mistarihi; Chan H. Yong

2008-01-01

332

Macroporous gels with fast response prepared by e-beam crosslinking of poly(N-isopropylacrylamide) solution  

Energy Technology Data Exchange (ETDEWEB)

Macroporous temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) gels exhibiting fast response rates were obtained by electron beam irradiation of aqueous polymer solutions. The effect of polymer concentration, irradiation temperature and dose, as well as addition of crosslinker was studied. The gels synthesized above the critical temperature from 20 wt.% polymer solution without crosslinker exhibited the highest equilibrium swelling and fastest response rate measured by seconds. The gels show reversible response to cyclical changes in temperature and might be used as actuators or pulsed drug release.

Safrany, Agnes [Institute of Isotopes, CRC HAS, P.O. Box 77, H-1525 Budapest (Hungary)]. E-mail: safrany@iki.kfki.hu

2005-07-01

333

Fast analytical methods for the correction of signal random time-shifts and application to segmented HPGe detectors  

CERN Document Server

Detection systems rely more and more on on-line or off-line comparison of detected signals with basis signals in order to determine the characteristics of the impinging particles. Unfortunately, these comparisons are very sensitive to the random time shifts that may alter the signal delivered by the detectors. We present two fast algebraic methods to determine the value of the time shift and to enhance the reliability of the comparison to the basis signals.

Désesquelles, P; Korichi, A; Blanc, F Le; Olariu, A; Petrache, C M; 10.1016/j.nimb.2008.11.042

2009-01-01

334

Planck 2013 results. VII. HFI time response and beams  

DEFF Research Database (Denmark)

This paper characterizes the effective beams, the effective beam window functions (EBWF) and the associated errors for the Planck High Frequency Instrument (HFI) detectors. The effective beam is the angular response including the effect of the optics, detectors, data processing and the scan strategy. The EBWF is the representation of this beam in the harmonic domain that is required to recover an unbiased measurement of the Cosmic Microwave Background (CMB) angular power spectrum. The HFI is a scanning instrument and its effective beams are the convolution of the optical response of the telescope and feeds, the processing of the time-ordered data and deconvolution of the bolometric and electronic time response, and the merging of several surveys to produce maps. The time response transfer functions are measured with observations of Jupiter and Saturn and by minimizing survey difference residuals. The scanning beam is the post-deconvolution angular response of the instrument, and is characterized with observations of Mars. The main beam solid angles are determined to better than 0.5% at each HFI frequency band. Observations of Jupiter and Saturn limit near sidelobes to ~0.1% of the total solid angle. Time response residuals remain as long tails in the scanning beams, but contribute

Planck Collaboration,, no-firstname; Ade, P. A. R.

2013-01-01

335

Low grade glioma - extent and timing of response to radiotherapy  

International Nuclear Information System (INIS)

Purpose/Objective: While postoperative radiotherapy has been suggested to improve survival in patients with subtotally resected low grade gliomas, their rate of radiographic response and correlation of response with outcome has not been well documented. Material and Methods: Twenty adults with non-pilocytic, supratentorial low grade gliomas treated between 1988-1995 who had measurable residual tumor after surgery and complete followup imaging were analysed for radiographic response to radiotherapy. The degree and timing of response to radiation were determined by comparing tumor volumes on post-operative/pre-radiation; post-radiation and subsequent follow-up CT scans. Radiographic response to radiotherapy was correlated with clinical symptomatology and progression free survival. Results: Median postoperative/pre-radiotherapy tumor volume was 32.5 cm3. At the time of maximal response post radiotherapy, volumes were reduced to a median of 13.5 cm3 for a median volume decrease of 7.5 cm3. Tumor response was judged as complete in(3(20)) , partial in (7(20)), minor in (6(20)) and stable in (4(20)) for an overall response rate of (16(20)) (80%). Of the 16 patients responding to radiotherapy, maximal response was seen on the first follow-up scan in 15 (median time to follow-up scan was 2.8 months following initiation of radiation treatments). Only one tumor had a protracted response, continuing to decrease in size between the end of radiation treatment and approximately 18 months later. A greater proportion of those patients exhibiting a response to radiation had an improvement in clinical symptomatology ((7(16))) versus non-responders ((0(4))). There were (5(20)) patients who developed recurrent tumor at a median of 32 months post-radiation for an actuarial 5 year progression free survival of 75%. All 5 who recurred had demonstrated an initial response to radiotherapy and all recurrences were within the previously radiated field. On univariate analysis of progression free survival KPS ? 70 was associated with improved survival (HR 0.928, p=0.037). Response to radiotherapy was inversely correlated with progression free survival (HR 3.599, p=0.040). Age, histology, extent of surgery and pre-radiation tumor volume were not significant predictors of progression free survival. Conclusions: This retrospective review of radiographic response of low grade gliomas to radiotherapy confirms that these tumors are radioresponsive. The majority demonstrated a 25% or greater reduction in volume as measured on serial CT scanning; usually by the first post radiation scan. Response of the tumors to radiotherapy predicted improved clinical symptomatology but not improved progression free survival.

336

Very fast two-dimensional NMR spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds.  

Science.gov (United States)

We demonstrate for different protein samples that 2D 1H-15N correlation NMR spectra can be recorded in a few seconds of acquisition time using a new band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence experiment. This has enabled us to measure fast hydrogen-deuterium exchange rate constants along the backbone of a small globular protein fragment by real-time 2D NMR. PMID:15926816

Schanda, Paul; Brutscher, Bernhard

2005-06-01

337

Very fast two-dimensional NMR spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds.  

UK PubMed Central (United Kingdom)

We demonstrate for different protein samples that 2D 1H-15N correlation NMR spectra can be recorded in a few seconds of acquisition time using a new band-selective optimized flip-angle short-transient heteronuclear multiple quantum coherence experiment. This has enabled us to measure fast hydrogen-deuterium exchange rate constants along the backbone of a small globular protein fragment by real-time 2D NMR.

Schanda P; Brutscher B

2005-06-01

338

A fast dynamic response dc-dc converter for high voltage applications  

International Nuclear Information System (INIS)

This paper present a fast dynamic response de-de converter for high voltage application such as medical use X-ray generator. In the proposed de-de converter a zero-current switching series resonant inverter is used to drive input terminals of voltage multiplier circuit. The zero-current switching series resonant inverter operates at fixed frequency and duly ratio. A control circuit is used at the lower arm of the inverter, to control the effective input voltage across the inverter. At the turn on the inverter is supplied with maximum effective input voltage, which results in quick rise-up of the output voltage. As the output voltage approaches to 80% of it target voltage, the effective input voltage is reduced to a value which corresponds to the target output voltage, as a result the rise rate of the output voltage becomes slow and overshoot is avoided. The effectiveness of the proposed control scheme has been confirmed experimentally with a laboratory scale- down prototype. (author)

2008-01-01

339

Hydriding/dehydriding characteristics on fast heat transfer response ZrCo bed for ITER  

Energy Technology Data Exchange (ETDEWEB)

Three models of fast heat transfer response ZrCo hydride bed were tested to examine their hydriding and dehydriding performance, and the hydrogen retention of the ZrCo during multiple hydriding and dehydriding operation. The design features of the present models are (i) very thin layer (3 mm) of ZrCo powder packing, (ii) large heating area in contact with the ZrCo powder (2.04 cm{sup 2}/g-ZrCo), and (iii) large filter surface area (1.76 cm{sup 2}/g-ZrCo) to reduce pressure drop across the filter during hydrogen delivery. To evaluate pumping conductance effect during dehydriding with vacuum pumping, two sizes of hydrogen pumping line were applied. Extremely high delivery rate of 1.3 x 10{sup -2} Pam{sup 3}/s for 90% delivery was observed in the 2nd and 3rd model tests. Hydrogen retention of {approx}1.5 x 10{sup -2} L-STP/g-ZrCo ({approx}2 L-STP/bed model) was observed in all models after multiple repetitions of hydridings and dehydriding under vacuum pumping: 25 cycles (1st model), 14 cycles (2nd model) and 70 cycles (3rd model). It was experimentally confirmed that the differences in the delivery rate and hydrogen retention the three model beds were predominantly generated by the difference in the pumping conductance (effective pumping speed) in the delivery pipeline.

Shim, Myunghwa [Korea Atomic Energy Research Institute, Yuseong, Daejeon 305-353 (Korea, Republic of); Chung, Hongsuk [Korea Atomic Energy Research Institute, Yuseong, Daejeon 305-353 (Korea, Republic of)], E-mail: hschung1@kaeri.kr; Yoshida, Hiroshi [Fusion Science Consultant, 3288-10, Sakado-cyo, Mito-shi, 310-0841 Ibakaki-ken (Japan); Jin, Haksu; Lee, Jongkuk [Korea Atomic Energy Research Institute, Yuseong, Daejeon 305-353 (Korea, Republic of); Song, Kyu-Min [KEPRI, Yuseong, Daejeon 305-380 (Korea, Republic of); Chang, Min Ho; Kang, Hyun-Goo; Yun, Sei-Hun; Cho, Seungyon [National Fusion Research Institute, Yuseong, Daejeon 305-333 (Korea, Republic of)

2009-06-15

340

Modeling the viscoplastic micromechanical response of two-phase materials using fast Fourier transforms  

Energy Technology Data Exchange (ETDEWEB)

A viscoplastic approach using the Fast Fourier Transform (FFT) method for obtaining local mechanical response is utilized to study microstructure-property relationships in composite materials. Specifically, three-dimensional, two-phase digital materials containing isotropically coarsened particles surrounded by a matrix phase, generated through a Kinetic Monte Carlo Potts model for Ostwald ripening, are used as instantiations in order to calculate the stress and strain rate fields under uniaxial tension. The effects of the morphology of the matrix phase, the volume fraction and the contiguity of particles, and the polycrystallinity of matrix phase, on the stress and strain rate fields under uniaxial tension are examined. It is found that the first moments of the stress and strain rate fields have a different dependence on the particle volume fraction and the particle contiguity from their second moments. The average stresses and average strain rates of both phases and of the overall composite have rather simple relationships with the particle volume fraction whereas their standard deviations vary strongly, especially when the particle volume fraction is high, and the contiguity of particles has a noticeable effect on the mechanical response. It is also found that the shape of stress distribution in the BCC hard particle phase evolves as the volume fraction of particles in the composite varies, such that it agrees with the stress field in the BCC polycrystal as the volume of particles approaches unity. Finally, it is observed that the stress and strain rate fields in the microstructures with a polycrystalline matrix are less sensitive to changes in volume fraction and contiguity of particles.

Lebensohn, Ricardo A [Los Alamos National Laboratory; Lee, Sukbin [CMU; Rollett, Anthony D [CMU

2009-01-01

 
 
 
 
341

Time domains of the hypoxic ventilatory response in ectothermic vertebrates.  

UK PubMed Central (United Kingdom)

Over a decade has passed since Powell et al. (Respir Physiol 112:123-134, 1998) described and defined the time domains of the hypoxic ventilatory response (HVR) in adult mammals. These time domains, however, have yet to receive much attention in other vertebrate groups. The initial, acute HVR of fish, amphibians and reptiles serves to minimize the imbalance between oxygen supply and demand. If the hypoxia is sustained, a suite of secondary adjustments occur giving rise to a more long-term balance (acclimatization) that allows the behaviors of normal life. These secondary responses can change over time as a function of the nature of the stimulus (the pattern and intensity of the hypoxic exposure). To add to the complexity of this process, hypoxia can also lead to metabolic suppression (the hypoxic metabolic response) and the magnitude of this is also time dependent. Unlike the original review of Powell et al. (Respir Physiol 112:123-134, 1998) that only considered the HVR in adult animals, we also consider relevant developmental time points where information is available. Finally, in amphibians and reptiles with incompletely divided hearts the magnitude of the ventilatory response will be modulated by hypoxia-induced changes in intra-cardiac shunting that also improve the match between O(2) supply and demand, and these too change in a time-dependent fashion. While the current literature on this topic is reviewed here, it is noted that this area has received little attention. We attempt to redefine time domains in a more 'holistic' fashion that better accommodates research on ectotherms. If we are to distinguish between the genetic, developmental and environmental influences underlying the various ventilatory responses to hypoxia, however, we must design future experiments with time domains in mind.

Porteus C; Hedrick MS; Hicks JW; Wang T; Milsom WK

2011-04-01

342

4? bismuth germanate (BGO) detector array for heavy ion physics and the prompt response of BGO to fast neutrons  

International Nuclear Information System (INIS)

[en] The properties of a gamma-ray facility proposed for the Chalk River MP tandem superconducting-cyclotron accelerator are described. The target is surrounded by a multi-segmented 4? BGO detector that determines, for each event, the ?-ray multiplicity, the spin orientation, and the total energy of the entry state in a ?-ray cascade. A small fraction of the ?-rays is detected outside the 4? array in up to eleven intrinsic Ge detectors, each of them inside a BGO Compton suppressor. The facility will allow high-resolution spectroscopy of discrete lines, with low Compton background and with strong enhancement of high-multiplicity events. Results of Monte Carlo calculations on the gamma-ray response of the facility are described. We have measured the prompt response of a 7.6 x 7.6 cm BGO detector to fast neutrons in the energy range from 0.4 to 10 MeV, using pulsed proton beams and time-of-flight methods. Both monoenergetic neutrons from the 7Li(p,n) reaction, and continuous neutron energy distributions from the 197Au(p,n) reaction were employed. The observed energy spectra in the BGO detector are dominated by ?-rays from the (n,n'?) reaction from Bi and Ge. Compared with a NaI(Tl) detector of the same volume, the neutron response of BGO is much smaller below E/sub n/ = 2 MeV because of the low density of levels in 209Bi, whereas above 3.5 MeV the neutron efficiencies are roughly the same. These results imply that a 4? detector made of BGO has a gamma-to-neutron detection ratio much superior to that of NaI(Tl)

1982-01-01

343

The time reversal effect of the impulse response of crust  

Science.gov (United States)

In this paper, the time reversal processes of impulse response of crust are simulated by means of a dynamical finite element method (DFEM). The results indicate that a small undulating load during a long period may cause a focused brevity impact in a chaos-response system. The physical principle for this phenomenon is that the wave interferes or multiples superposition. Based on this knowledge, a new view toward the mechanism for preparing and triggering an earthquake is proposed. Finally, an interpretation of crust response to the sea tides is given.

Zheng, Wen-Heng; Wang, Cheng; Chen, Xiang-Peng

2001-07-01

344

Sensors Response Time validation using Dimensionality Reduction Techniques  

Directory of Open Access Journals (Sweden)

Full Text Available The temperature and Pressure sensors play a vital role in Nuclear Power Plants (NPP). The Rosemount temperature sensor helps to produce the exact temperature and pressure measurement of the nuclear power plant. The sensors that supply real data must respond quickly to the safety systems of NPP. In this paper, first the Dimensionality of the Original dataset is reduced by using Principal Component Analysis (PCA), Independent Component Analysis (ICA) and Singular Value Decomposition (SVD). Finally the sensors Response Time is computed and compared with original response time.

S. Gayathri; N. Sairam

2013-01-01

345

Dynamical theory of responsivity and response time of a high temperature superconductor photo-thermoelectrical bolometer  

Energy Technology Data Exchange (ETDEWEB)

Dynamical theory of responsivity and response time for an high temperature superconductor (HTSC) photo-thermoelectrical bolometer is analysed in this paper. There is a thermoelectric feedback (TEF) due to the heat transfer from the sensitive area (HTSC-BiSb thermojunction) towards the cold junction of the thermocouple. This is in addition to the normal electrothermal feedback (ETF) between the detector and the substrate, in a photoelectrical bolometer. The two legs of the thermocouple are connected in a parallel geometry configuration. It is seen that TEF can be used in combination with the ETF to enhance responsivity and response time of the detector.

Kaila, M.M

2002-11-01

346

Dynamical theory of responsivity and response time of a high temperature superconductor photo-thermoelectrical bolometer  

International Nuclear Information System (INIS)

[en] Dynamical theory of responsivity and response time for an high temperature superconductor (HTSC) photo-thermoelectrical bolometer is analysed in this paper. There is a thermoelectric feedback (TEF) due to the heat transfer from the sensitive area (HTSC-BiSb thermojunction) towards the cold junction of the thermocouple. This is in addition to the normal electrothermal feedback (ETF) between the detector and the substrate, in a photoelectrical bolometer. The two legs of the thermocouple are connected in a parallel geometry configuration. It is seen that TEF can be used in combination with the ETF to enhance responsivity and response time of the detector

2002-11-01

347

Fast Geometric T2-Fuzzy Based Improved Lower Extremities Stimulation Response  

Directory of Open Access Journals (Sweden)

Full Text Available This study emphasizes the use of type-2 fuzzy (T2-Fuzzy) adaptive proportional-integrative-derivative (PID) control to replace the previous research. The problem that emerged in previous studies is the achievement of the target angle is slow, and the oscillations in the achievement of the target blade. Alleged causes of the oscillations due to the early adaptive PID have not been enough to overcome the nonlinearity lower extremities. The difference between methods of using T2-Fuzzy with others T2-Fuzzy lies in the method defuzzification. This research used defuzzification fast geometric that maintain the level of T2-Fuzzy uncertainty, can also be applied in real-time. A functional electrical stimulation (FES) stimulator designed and connected to the computer as a processing T2-Fuzzy. It stimulates lower extremities of normal subjects each cycle, and the computer recorded the point of achievement as measured using a goniometer sensors mounted on a knee joint. The results of the achievement of the target point of the lower extremities of range at three initial cycles, and no oscillations occur in the achievement of the angle. It also found that T2-Fuzzy able to immediately restore the point of achievement when the external parameters of control occurs.

Hendi Wicaksono

2010-01-01

348

Fast response double series resonant high-voltage DC-DC converter  

International Nuclear Information System (INIS)

In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

2012-01-01

349

Fast response double series resonant high-voltage DC-DC converter  

Science.gov (United States)

In this paper, a novel double series resonant high-voltage dc-dc converter with dual-mode pulse frequency modulation (PFM) control scheme is proposed. The proposed topology consists of two series resonant tanks and hence two resonant currents flow in each switching period. Moreover, it consists of two high-voltage transformer with the leakage inductances are absorbed as resonant inductor in the series resonant tanks. The secondary output of both transformers are rectified and mixed before supplying to load. In the resonant mode operation, the series resonant tanks are energized alternately by controlling two Insulated Gate Bipolar Transistor (IGBT) switches with pulse frequency modulation (PFM). This topology operates in discontinuous conduction mode (DCM) with all IGBT switches operating in zero current switching (ZCS) condition and hence no switching loss occurs. To achieve fast rise in output voltage, a dual-mode PFM control during start-up of the converter is proposed. In this operation, the inverter is started at a high switching frequency and as the output voltage reaches 90% of the target value, the switching frequency is reduced to a value which corresponds to the target output voltage. This can effectively reduce the rise time of the output voltage and prevent overshoot. Experimental results collected from a 100-W laboratory prototype are presented to verify the effectiveness of the proposed system.

Lee, S. S.; Iqbal, S.; Kamarol, M.

2012-10-01

350

Time response of protection in event of vacuum failure based on Nude ionization gauge controller  

Science.gov (United States)

This article describes the design and application of fast-response vacuum protection sensor module, based on the Nude ionization gauge and a homemade controller named GH07X. A simulative test indicated that the controller's response time was less than 200 ?s when 1 atm air rushed into the vacuum system through a pulsed valve with 0.8 mm orifice nozzle and the emitting current of the Nude gauge was 4 mA. The experiment result showed that the response time mainly depended on the gas density as well as the electron emitting current of the Nude gauge filament. Compared with the vacuum protection sensors based on sputter ion pump and cold-cathode gauge, GH07X is faster and reliable besides, GH07X can be used as an ultrahigh-vacuum slow valve interlock controller with response time of 100 ms, which is faster than other gauge controllers. The widely used field-bus interface CAN and common serial interface RS232/RS485 are embedded in GH07X controller system.

Gao, Hui; Wang, Qiuping; Wang, Weibin; Wu, Qinglin; Chen, Wentong; Sheng, Liusi; Zhang, Yunwu

2001-10-01

351

Radiation response in 10 high-grade human soft tissue sarcoma xenografts to photons and fast neutrons  

Energy Technology Data Exchange (ETDEWEB)

From a panel of 48 human soft tissue sarcomas growing as permanent xenografts, 10 tumor lines (five leiomyosarcomas, three malignant fibrous histiocytomas, two neurofibrosarcomas) have been selected to determine the radiation response to photons and fast neutrons. Using the specific growth delay (SGD) as an end-point, considerable variability of inherent radiosensitivity was observed. Isoeffective radiation doses varied by a factor of 27 for photons and of 9.4 for neutrons at a specific growth delay level of 0.5. The heterogeneity of the relative biological effectiveness (RBE) at this specific growth delay-level differed by a factor of 8. Relative biological effectiveness values for clamped tumors exceeded those of the normal tissues (RBE approximately 3) in 6 out of 10 tumor lines. Assuming a ratio of 0.5 for oxygen enhancement ratio-values of neutrons and photons, a therapeutic gain for neutrons existed in 4 out of 10 tumor lines under oxic conditions. No correlation between volume doubling times and relative biological effectiveness was seen.

Budach, V.; Stuschke, M.; Budach, W.; Molls, M.; Sack, H. (Univ. of Essen (Germany, F.R.))

1990-10-01

352

Properties of excitatory synaptic responses in fast-spiking interneurons and pyramidal cells from monkey and rat prefrontal cortex.  

UK PubMed Central (United Kingdom)

In the prefrontal cortex (PFC) during working memory tasks fast-spiking (FS) interneurons might shape the spatial selectivity of pyramidal cell firing. In order to provide time control of pyramidal cell activity, incoming excitatory inputs should excite FS interneurons more vigorously than pyramidal cells. This can be achieved if subthreshold excitatory responses of interneurons are considerably stronger and faster than those in pyramidal neurons. Here we compared the functional properties of excitatory post-synaptic potentials (EPSPs) between pyramidal cells and FS interneurons in slices from monkey dorsolateral PFC and rat prelimbic cortex. Miniature, unitary (in connected pairs or by minimal stimulation) and compound (evoked by electrical stimulation of the white matter) EPSPs were recorded in whole cell mode. We found that EPSPs were significantly larger and faster in FS interneurons than those recorded from pyramidal cells, consistent with the idea of more efficient recruitment of FS interneurons compared to pyramidal neurons. Similar results were obtained in monkey and rat PFC, suggesting a stable role of FS interneurons in this circuitry across species.

Povysheva NV; Gonzalez-Burgos G; Zaitsev AV; Kröner S; Barrionuevo G; Lewis DA; Krimer LS

2006-04-01

353

Study of toroidal current penetration during current ramp in JIPP T-IIU with fast response Zeeman polarimeter  

Energy Technology Data Exchange (ETDEWEB)

The toroidal current penetration is studied in current ramp experiments of the JIPP T-IIU tokamak. The poloidal magnetic field profile in the peripheral region of a plasma (0.5 {<=} {rho} {<=} 1.0) has been measured directly with a newly developed fast response Zeeman polarimeter. The experimental results indicate that an obvious skin effect of toroidal current density is clearly observed during both the current ramp-up and ramp-down experiments. The experimentally obtained toroidal current density profiles are well described by the profiles calculated on the assumption of the neoclassical electrical conductivity. Quasi-linear {Delta}`-analysis of tearing modes for the measured current density profile is consistent with time behaviour of coherent MHD modes such as m=4/n=1 or m=3/n=1 (m: poloidal mode number, n: toroidal mode number) often observed during the current ramp-up phase. The effect of these MHD modes on current penetration during the current ramp-up discharges is studied. (author)

Kuramoto, H.; Hiraki, N. [Kyushu Inst. of Tech., Kitakyushu, Fukuoka (Japan); Toi, K. [and others

1997-01-01

354

Unsaturated-zone fast-path flow calculations for Yucca Mountain groundwater travel time analyses (GWTT-94)  

Energy Technology Data Exchange (ETDEWEB)

Evaluation of groundwater travel time (GWTT) is required as part of the investigation of the suitability of Yucca Mountain as a potential high-level nuclear-waste repository site. The Nuclear Regulatory Commission`s GWTT regulation is considered to be a measure of the intrinsic ability of the site to contain radionuclide releases from the repository. The work reported here is the first step in a program to provide an estimate of GWTT at the Yucca Mountain site in support of the DOE`s Technical Site Suitability and as a component of a license application. Preliminary estimation of the GWTT distribution in the unsaturated zone was accomplished using a numerical model of the physical processes of groundwater flow in the fractured, porous medium of the bedrock. Based on prior investigations of groundwater flow at the site, fractures are thought to provide the fastest paths for groundwater flow; conditions that lead to flow in fractures were investigated and simulated. Uncertainty in the geologic interpretation of Yucca Mountain was incorporated through the use of geostatistical simulations, while variability of hydrogeologic parameters within each unit was accounted for by the random sampling of parameter probability density functions. The composite-porosity formulation of groundwater flow was employed to simulate flow in both the matrix and fracture domains. In this conceptualization, the occurrence of locally saturated conditions within the unsaturated zone is responsible for the initiation of fast-path flow through fractures. The results of the GWTT-94 study show that heterogeneity in the hydraulic properties of the model domain is an important factor in simulating local regions of high groundwater saturation. Capillary-pressure conditions at the surface boundary influence the extent of the local saturation simulated.

Arnold, B.W.; Altman, S.J. [Sandia National Labs., Albuquerque, NM (United States); Robey, T.H. [Spectra Research Institute, Albuquerque, NM (United States)] [and others

1995-08-01

355

Unsaturated-zone fast-path flow calculations for Yucca Mountain groundwater travel time analyses (GWTT-94)  

International Nuclear Information System (INIS)

Evaluation of groundwater travel time (GWTT) is required as part of the investigation of the suitability of Yucca Mountain as a potential high-level nuclear-waste repository site. The Nuclear Regulatory Commission's GWTT regulation is considered to be a measure of the intrinsic ability of the site to contain radionuclide releases from the repository. The work reported here is the first step in a program to provide an estimate of GWTT at the Yucca Mountain site in support of the DOE's Technical Site Suitability and as a component of a license application. Preliminary estimation of the GWTT distribution in the unsaturated zone was accomplished using a numerical model of the physical processes of groundwater flow in the fractured, porous medium of the bedrock. Based on prior investigations of groundwater flow at the site, fractures are thought to provide the fastest paths for groundwater flow; conditions that lead to flow in fractures were investigated and simulated. Uncertainty in the geologic interpretation of Yucca Mountain was incorporated through the use of geostatistical simulations, while variability of hydrogeologic parameters within each unit was accounted for by the random sampling of parameter probability density functions. The composite-porosity formulation of groundwater flow was employed to simulate flow in both the matrix and fracture domains. In this conceptualization, the occurrence of locally saturated conditions within the unsaturated zone is responsible for the initiation of fast-path flow through fractures. The results of the GWTT-94 study show that heterogeneity in the hydraulic properties of the model domain is an important factor in simulating local regions of high groundwater saturation. Capillary-pressure conditions at the surface boundary influence the extent of the local saturation simulated.

1995-01-01

356

Vectorised simulation of the response of a time projection chamber  

International Nuclear Information System (INIS)

A Monte Carlo code used for the detailed simulation of the response of the ALEPH time projection chamber has been successfully restructed to exploit the vector architectures of the CDC CYBER-205, ETA10 and CRAY X-MP supercomputers. Some aspects of the vector implementation are discussed and the performance on the various processors is compared. (orig.).

1989-01-01

357

Changing Roles, Relationships and Responsibilities in Changing Times  

Science.gov (United States)

Professional experience in initial teacher education continues to be a very challenging area in which to work in Australian universities, given the changing times in which we live and the multiplicity of political, professional, economic and pragmatic issues that surround professional placements. The past decades have seen myriad responses to…

Le Cornu, Rosie

2010-01-01

358

Mathematical programming modelling of the response time variability problem  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Response Time Variability Problem (RTVP) is a scheduling problem that has recently been defined in the literature. The RTVP has a broad range of real-life applications. For example, in the automobile industry it an be used to sequence the models to be produced on a mixed-model assembly line. A p...

Corominas Subias, Albert; Pastor Moreno, Rafael; Kubiak, Wieslaw

359

Improvement in MFTF data base system response times  

Energy Technology Data Exchange (ETDEWEB)

The Supervisory Control and Diagnostic System for the Mirror Fusion Test Facility (MFTF) has been designed as an event driven system. To this end we have designed a data base notification facility in which a task can request that it be loaded and started whenever an element in the data base is changed beyond some user defined range. Our initial implementation of the notify facility exhibited marginal response times whenever a data base table with a large number of outstanding notifies was written into. In this paper we discuss the sources of the slow response and describe in detail a new structure for the list of notifies which minimizes search time resulting in significantly faster response.

Lang, N.C.; Nelson, B.C.

1983-11-28

360

Improvement in MFTF data base system response times  

International Nuclear Information System (INIS)

The Supervisory Control and Diagnostic System for the Mirror Fusion Test Facility (MFTF) has been designed as an event driven system. To this end we have designed a data base notification facility in which a task can request that it be loaded and started whenever an element in the data base is changed beyond some user defined range. Our initial implementation of the notify facility exhibited marginal response times whenever a data base table with a large number of outstanding notifies was written into. In this paper we discuss the sources of the slow response and describe in detail a new structure for the list of notifies which minimizes search time resulting in significantly faster response

1983-01-01

 
 
 
 
361

Time course of tension development of knee extensor muscle on twitch, tetanic, and fast voluntary contraction in normal subjects.  

UK PubMed Central (United Kingdom)

Tension lag time (TLT), a latency from the onset of electromyographic activities of prime mover muscle to the rise of tension, of knee extensor muscle was measured at twitch, tetanic, and fast voluntary contraction in three normal subjects. Twitch and tetanic contractions were evoked by four different strengths of electrical stimuli, and the peak tensions attained at fast voluntary contraction were within the range of tensions evoked by electrical stimulation. In each mode of contraction, the relationship between TLT and peak tension (Fmax) was approximated by a hyperbolic function of Fmax (TLT-a) = b. TLT was influenced by three factors: (1) Fmax, the greater Fmax, the shorter TLT; (2) force detection level to point out timing of the rise of tension, the higher the level, the longer TLT was; and (3) the mode of contraction, shortest at the twitch, longest at the voluntary, and intermediate in the tetanic contraction.

Tsuji I; Nakamura R

1988-07-01

362

Well vertically aligned ZnO nanowire arrays with an ultra-fast recovery time for UV photodetector  

Energy Technology Data Exchange (ETDEWEB)

Well-crystallized ZnO nanowire arrays were grown on GaN/sapphire by one-step chemical vapor deposition under control of the fabrication pressure of 1000-2500 Pa and the best-aligned arrays were obtained at 1000 Pa. A photoluminescence study shows a red shift with nanowire diameter increase. Under 365-nm UV irradiation of 0.3 mW/cm{sup 2}, the photoresponse study of the best ZnO arrays shows an ultra-fast tri-exponential rise with three constants of 0.148, 0.064 and 0.613 s, and a bi-exponential decay behavior with two recovery constants of 30 and 270 ms. The ZnO/GaN heterojunction barriers could be responsible for the ultra-fast tri-exponential rise and bi-exponential decay behavior. (orig.)

Zhang, Xianghui; Su, Jun; Zhang, Qi; Gao, Yihua [Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, School of Physics, College of Optoelectronic Science and Engineering, Wuhan, Hubei (China); Han, Xiangyun [Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, School of Physics, College of Optoelectronic Science and Engineering, Wuhan, Hubei (China); Chongqing Police College, Chongqing (China)

2012-05-15

363

The noise-time of response compromise in d.c. period meters. A new type of circuit (1961)  

International Nuclear Information System (INIS)

The report compares the characteristics of three period meter circuits: - a linear circuit - a circuit which is non-linear according to the nuclear reactor period - a circuit which is non-linear according to the period and the power of the reactor. This last type of reactor has a fast time of response if the power is high or if the period is short, and it has a slow time of response when the power is low and the period long; this system makes it possible to maintain the noise at an acceptable level under all normal working conditions of the reactor. (author)

1961-01-01

364

Implementation of rooftop reciculation parameterization into the QUIC fast response urban wind model  

Energy Technology Data Exchange (ETDEWEB)

The QUIC (Quick Urban & Industrial Complex) dispersion modeling system has been developed to provide high-resolution wind and concentration fields in cities. The fast response 3D urban wind model QUIC-URB explicitly solves for the flow field around buildings using a suite of empirical parameterizations and mass conservation. This procedure is based on the work of Rockle (1990). The current Rockle (1990) model does not capture the rooftop recirculation region associated with flow separation from the leading edge of an isolated building. According to Banks et al. (2001), there are two forms of separation depending on the incident wind angle. For an incident wind angle within 20{sup o} of perpendicular to the front face of the building, 'bubble separation' occurs in which cylindrical vortices whose axis are orthogonal to the flow are generated along the rooftop surface (see Fig. 1). For a 'corner wind' flow or incident wind angle of 30{sup o} to 70{sup o} of perpendicular to the front face of the building, 'conical' or 'delta wing' vortices form along the roof surface (Fig. 3). In this work, a model for rooftop recirculation is implemented into the QUIC- URB model for the two incident wind angle regimes described above. The parameterizations for the length and height of the recirculation region are from Wilson (1979) for the case of flow perpendicular or near perpendicular to the building and from Banks et al. (2000) for the case of off-angle flow. In this paper, we describe the rooftop algorithms and show how the model results are improved through comparisons to experimental data (Snyder and Lawson 1994).

Bagal, N. (Nilesh); Singh, B. (Balwinder); Pardyjak, E. R. (Eric R.); Brown, M. J. (Michael J.)

2004-01-01

365

Comparison of LMFBR piping response obtained using response spectrum and time history methods  

International Nuclear Information System (INIS)

The dynamic response to a seismic event is calculated for a piping system using a response spectrum analysis method and two time history analysis methods. The results from the analytical methods are compared to identify causes for the differences between the sets of analytical results. Comparative methods are also presented which help to gain confidence in the accuracy of the analytical methods in predicting piping system structure response during seismic events

1981-06-26

366

Dose-time-response modeling using negative binomial distribution.  

Science.gov (United States)

People exposed to certain diseases are required to be treated with a safe and effective dose level of a drug. In epidemiological studies to find out an effective dose level, different dose levels are applied to the exposed and a certain number of cures is observed. Negative binomial distribution is considered to fit overdispersed Poisson count data. This study investigates the time effect on the response at different time points as well as at different dose levels. The point estimation and confidence bands for ED 100p (t) and LT 100p (d) are formulated in closed form for the proposed dose-time-response model with the negative binomial distribution. Numerical illustrations are carried out in order to check the performance level of the proposed model. PMID:24138430

Roy, Munmun; Choudhury, Kanak; Islam, M M; Matin, M A

2013-01-01

367

Dose-time-response modeling using negative binomial distribution.  

UK PubMed Central (United Kingdom)

People exposed to certain diseases are required to be treated with a safe and effective dose level of a drug. In epidemiological studies to find out an effective dose level, different dose levels are applied to the exposed and a certain number of cures is observed. Negative binomial distribution is considered to fit overdispersed Poisson count data. This study investigates the time effect on the response at different time points as well as at different dose levels. The point estimation and confidence bands for ED 100p (t) and LT 100p (d) are formulated in closed form for the proposed dose-time-response model with the negative binomial distribution. Numerical illustrations are carried out in order to check the performance level of the proposed model.

Roy M; Choudhury K; Islam MM; Matin MA

2013-01-01

368

Mesh-Shrink: Real-Time Fast Moving Object Tracking with Sporadic Occlusion  

Directory of Open Access Journals (Sweden)

Full Text Available This paper proposes a new method for real-timeobject tracking in scenarios where the target moves fast but itsappearance does not change quickly. By creating a mesh on thecurrent frame, we set nodes of the mesh as candidate positionsof the target. Several adjacent nodes which are more similar tothe target constitute a new smaller search region, on which anew finer mesh is created. The approach iterates until certainconditions are satisfied. Finally, one of the nodes is identified asthe target location. Unlike existing tracking methods, thisapproach achieves tracking of fast moving object in real timeand is capable of recovering tracking when the target is missingdue to full occlusion, or moving out of the image area andreappearing in the near future frames. The method does notrequire complicated computation and thus can be applied to theenvironment which permits only limited computing resources.The capabilities of the tracking based on our method aredemonstrated by several image sequences.

Wei Quan; Jim X. Chen; Nanyang Yu

2013-01-01

369

A fast, flexible and low cost real time data acquisition system for nuclear physics experiments  

International Nuclear Information System (INIS)

A system has been developed to permit fast, efficient data collection from a relatively complex nuclear experiment. Incorporated into this system is the communication framework for on-line analysis of the incoming data. The system makes extensive use of readily available low cost Intel based microprocessors. Results from recent measurements of the 16O(?,n) cross section made using tagged photons, performed at previously unachievable collection rates are presented. 6 refs., 6 figs

1991-01-01

370

Injection-time effects on falloff responses from composite reservoirs  

Energy Technology Data Exchange (ETDEWEB)

An analytical solution for a radial, composite reservoir is used to establish dimensionless injection time based on the front radius as a correlating parameter for falloff responses of all front radii. Effects of short injection time on the accuracy of methods used to estimate swept volume (or front radius) are discussed. If injection-time effects are ignored, the pseudo-steady-stage method may overestimate swept volume by an order of magnitude. For short injection times, model selection (a two- vs. three-region model) for type-curve matching can be difficult. Finally, a correlation is presented for the magnitude of injection time to analyze falloff data with an injectivity type curve.

Ambastha, A.K. (Univ. of Tulsa, Tulsa, OK (US)); Ramey, H.J. Jr. (Stanford Univ., Stanford, CA (US))

1990-12-01

371

Comparison of Intestinal Response of Chicks from Light and Heavy Eggs to Posthatch Fasting  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of posthatch fasting on villi height and number, crypt depth and number of globet cells in duodenum, jejunum and ileum of broiler chicks from heavy and light eggs were compared. The 2 x 3 x 3 factorial design (egg weight: light and heavy eggs; treatments: with water and feed, with water, without water and feed; treatment duration: 24, 48 and 72 h) was used. The villi presented higher size in chicks from heavy than from light eggs. The fasting resulted in lower villi in duodenum (at 48 h), jejunum and ileum (at 72 h). The villi number increased in duodenum and jejunum of chicks from light eggs and only in jejunum of chicks from heavy eggs, but the increase was more accented in chicks from light ones. The fasting reduced the globet cells number in jejunum. Water intake avoided the fasting effects on villi height but had no effect on villi number. Chicks from heavy eggs fed with water and ration presented deeper crypts in all regions of the small intestine. The duodenum and ileum crypt depth of the chicks from heavy eggs reduced when they were submitted to fasting and when they were fed only with water. The results showed that chicks from light eggs were more affected than chicks from heavy eggs. The water intake partially avoided the fasting effects.

Rafael Raile Riccardi; Euclides Braga Malheiros; Isabel Cristina Boleli

2011-01-01

372

A GEANT4 study on the time resolution of a fast plastic scintillator read out by a G-APD  

Science.gov (United States)

The time resolution of a fast scintillation counter, consisting of a plastic scintillator read out by a Geiger-mode Avalanche Photodiode, is studied over a wide range of the number of detected photons (primary photoelectrons) using the GEANT4 simulation toolkit. Different timing definitions such as first photon detection, leading edge and constant fraction discrimination are considered. In the latter case the predictions are compared with the existing experimental data. We also show that due to the finite scintillation rise time, finite scintillator dimensions and also due to the finite single photon time resolution in G-APD cells, the time resolution for the first detected photon in real detectors substantially deviates from the ??1/Nphe dependence, theoretically predicted for a scintillator with zero rise time.

Sedlak, K.; Stoykov, A.; Scheuermann, R.

2012-12-01

373

Response times follow lognormal or gamma distribution in arthritis patients.  

UK PubMed Central (United Kingdom)

OBJECTIVE: This study evaluated the statistical distribution of time to treatment response in patients with rheumatic diseases. STUDY DESIGN AND SETTING: The study used a secondary data analysis design. Data from the trial of etanercept and methotrexate with radiographic patient outcomes were used to model the response times for etanercept (ETN), methotrexate (MTX), and combined ETN+MTX in patients with rheumatoid arthritis. The German etanercept registry was used to evaluate the response time distributions in patients with juvenile idiopathic arthritis. RESULTS: For MTX, the lognormal distribution was considered to be the best model for the outcome American College of Rheumatology (ACR20), lognormal, generalized gamma, and log-logistic distributions for ACR50, and lognormal and generalized gamma for ACR70. For ETN, the lognormal model was best for ACR20, the generalized gamma for ACR50, and both lognormal and generalized gamma distributions for ACR70. For combined treatment, the best model was the log-logistic distribution for ACR20, generalized gamma for ACR50, and both lognormal and generalized gamma distributions for ACR70. For the German etanercept registry, the lognormal distribution was the best model for all three outcomes of pediatric ACR30, ACR50, and ACR70 without interval censoring. CONCLUSION: Study designs might be more efficient if the response distributions are taken into consideration during planning.

Abrahamyan L; Beyene J; Feng J; Chon Y; Willan AR; Schmeling H; Horneff G; Keystone EC; Feldman BM

2010-12-01

374

"Real-time" disintegration analysis and D-optimal experimental design for the optimization of diclofenac sodium fast-dissolving films.  

Science.gov (United States)

The objective of this work was to study the dissolution and mechanical properties of fast-dissolving films prepared from a tertiary mixture of pullulan, polyvinylpyrrolidone and hypromellose. Disintegration studies were performed in real-time by probe spectroscopy to detect the onset of film disintegration. Tensile strength and elastic modulus of the films were measured by texture analysis. Disintegration time of the films ranged from 21 to 105 seconds whereas their mechanical properties ranged from approximately 2 to 49?MPa for tensile strength and 1 to 21 MPa% for young's modulus. After generating polynomial models correlating the variables using a D-Optimal mixture design, an optimal formulation with desired responses was proposed by the statistical package. For validation, a new film formulation loaded with diclofenac sodium based on the optimized composition was prepared and tested for dissolution and tensile strength. Dissolution of the optimized film was found to commence almost immediately with 50% of the drug released within one minute. Tensile strength and young's modulus of the film were 11.21?MPa and 6, 78 MPa%, respectively. Real-time spectroscopy in conjunction with statistical design were shown to be very efficient for the optimization and development of non-conventional intraoral delivery system such as fast dissolving films. PMID:22780708

El-Malah, Yasser; Nazzal, Sami

2012-07-11

375

Effect of a carbohydrate mouth rinse on simulated cycling time-trial performance commenced in a fed or fasted state.  

UK PubMed Central (United Kingdom)

It is presently unclear whether the reported ergogenic effect of a carbohydrate (CHO) mouth rinse on cycling time-trial performance is affected by the acute nutritional status of an individual. Hence, the aim of this study was to investigate the effect of a CHO mouth rinse on a 60-min simulated cycling time-trial performance commenced in a fed or fasted state. Twelve competitive male cyclists each completed 4 experimental trials using a double-blinded Latin square design. Two trials were commenced 2 h after a meal that contained 2.5 g·kg(-1) body mass of CHO (FED) and 2 after an overnight fast (FST). Prior to and after every 12.5% of total time during a performance ride, either a 10% maltodextrin (CHO) or a taste-matched placebo (PLB) solution was mouth rinsed for 10 s then immediately expectorated. There were significant main effects for both pre-ride nutritional status (FED vs. FST; p < 0.01) and CHO mouth rinse (CHO vs. PLB; p < 0.01) on power output with an interaction evident between the interventions (p < 0.05). The CHO mouth rinse improved mean power to a greater extent after an overnight fast (282 vs. 273 W, 3.4%; p < 0.01) compared with a fed state (286 vs. 281 W, 1.8%; p < 0.05). We concluded that a CHO mouth rinse improved performance to a greater extent in a fasted compared with a fed state; however, optimal performance was achieved in a fed state with the addition of a CHO mouth rinse.

Lane SC; Bird SR; Burke LM; Hawley JA

2013-02-01

376

Residential response to voluntary time-of-use electricity rates  

Energy Technology Data Exchange (ETDEWEB)

The response of residential households to voluntary Time-of-Use (TOU) electricity rates is estimated using data from a recent experiment at Midwest Power Systems of Iowa. The study`s design allows us to examine both the participation decision and the customer`s load pattern changes once the TOU rate structure was in effect. Substitution elasticities between on-peak and off-peak electricity usage are estimated and compared to those obtained in earlier mandatory programs, indicating whether program volunteers are more responsive to TOU pricing than the typical household. Attitudinal questionnaires allow us to examine the role of usage perceptions in program participation

Mostafa Baladi, S. [Laurits R. Christensen Associates, Inc. Ames, IA 50011-1070 (United States); Herriges, Joseph A. [Iowa State University, 280D Heady Hall, Department of Economics, Iowa State University, Ames, IA 50011-1070 (United States); Sweeney, Thomas J. [MidAmerican Energy, Des Moines, Iowa (United States)

1998-09-01

377

Timely response to secure messages from primary care patients.  

UK PubMed Central (United Kingdom)

PURPOSE: To assess delays in response to patient secure e-mail messages in primary care. BACKGROUND: Secure electronic messages are initiated by primary care patients. Timely response is necessary for patient safety and quality. DATA SOURCE: A database of secure messages. SAMPLE: A random sample of 353 secure electronic messages initiated by primary care patients treated in 4 clinics. OUTCOME MEASURES: Message not opened after 12 hours or messages not responded to after 36 hours. RESULTS: A total of 8.5% of electronic messages were not opened within 12 hours, and 17.6% did not receive a response in 36 hours. Clinic location, being a clinic employee, and patient sex were not related to delays. Patients older than 50 years were more likely to receive a delayed response (25.7% delayed, P = .013). The risk of both kinds of delays was higher on weekends (P < .001 for both). CONCLUSION: The e-mail message system resulted in high rates of delayed response. Delays were concentrated on weekends (Friday-Sunday). Reducing delayed responses may require automatic rerouting of messages to message centers staffed 24-7 or other mechanisms to manage this after-hours work flow.

Rohrer JE; North F; Angstman KB; Oberhelman SS; Meunier MR

2013-04-01

378

A Novel of Hybrid Magnet Engine Valve Actuator Using Shorted Turn for Fast Initial Response  

Directory of Open Access Journals (Sweden)

Full Text Available A variable valve timing (VVT) can improve fuel efficiency, reduce CO2 emission and increase torque output. To achieve VVT in internal combustion engine, new devices such as mechanical, hydraulic, motor-driven and electromagnetic actuator have been developed in past years to replace the conventional camshaft valve train system used currently. Among these, the electromagnetic actuator using solenoids is the most advance system to provide the most flexibility to valve timing, but it has critical drawback of high power consumption. This paper presents a novel design of Hybrid Magnet Engine Valve Actuator (HMEVA) using shorted turn. A shorted turn is placed into existing design in order to reduce the inductance of coil and improve the initial response. Dynamic finite element analysis using commercial electromagnetic solver “MAXWEL” is performed to simulate the improvement of dynamic characteristic of model.

DucThuan Vu; Hwang Pyung

2013-01-01

379

A "package solution" fast track program can reduce the diagnostic waiting time in head and neck cancer.  

Science.gov (United States)

In 2007, a fast track program for patients with suspicion of head and neck cancer (HNC) was introduced in Denmark to reduce unnecessary waiting time. The program was based on so called "package solutions" including pre-booked slots for outpatient evaluation, imaging, and diagnostic surgical procedures. The purpose of this study is to present a model for fast track handling of patients suspicious of cancer in the head and neck region and to evaluate the effect of implementation on the diagnostic work up time. Patients with suspicion of HNC referred to the same university department of ENT Head and Neck Surgery during three comparable time intervals 2006-2007, 2007-2008, and 2011-2012 (groups 1-3) were investigated. We recorded the time from patient referral, to first consultation and final diagnosis. The first interval was before initiation of the "package solution", the second just after the introduction, and the third interval represents the current situation. The median time from referral to first consultation was reduced from eight calendar days in group 1 to only one day in groups 2 and 3 (p HNC was 19 % in group 1, 21 % in group 2, and 17 % in group 3 (p = 0.52). A "package solution" including pre-booked slots for diagnostic procedures is feasible and can significantly reduce the waiting time for patients with suspicion of HNC. PMID:23775302

Sorensen, Jesper Roed; Johansen, Jørgen; Gano, Lars; Sørensen, Jens Ahm; Larsen, Stine Rosenkilde; Andersen, Peter Bøgeskov; Thomassen, Anders; Godballe, Christian

2013-06-18

380

Response time of Saguenay fjord sediments to metal contamination  

International Nuclear Information System (INIS)

Dated sediment cores record, with varying degrees of time lag, the recent (1946-1976) history of natural and industrial inputs of Hg and other metals into the Saguenay Fjord, Quebec. This is illustrated in a dated core from an oxic basin near the head of the fjord. The core was analyzed at 1 cm intervals for Hg, Zn, Pb, Cu, Co, Ni, Cr, V, Cd, organic carbon Pb210, and Cs137. Partitioning of the metals between the silicate, organic, and non-detrial phases and factor analyses of the data indicate that terrigenous organic matter is the main scavenging agent and carrier for the transport and deposition of Hg and available Zn, and V to the sediments. Radiometric dating indicates that Hg and other small but significant amounts of Zn, Pb, and V contamination began about 1948 after a chlor-alkali plant began production on the river entering the fjord. Inputs of Hg and other metals to the sediments from the plant and associated industries increased with time and reached maximum rates in the late 1960s and early 1970s before declining in response to pollution controls. Comparison of the variation in Hg fluxes recorded in the core with changes in the calculated industrial inputs shows that the time lag between the two curves is 1 to 2 years at this site, but at other sites the time response varied from a few months at the head of the fjord to 10-15 years at the seaward end. These variations in time response relate to sedimentation rates, residence times in the water column, distance from source and to changes in the flux of terrigenous organic matter to the fjord sediments.(author)

1983-01-01

 
 
 
 
381

Slow-fast dynamics of a time-delayed electro-optic oscillator.  

UK PubMed Central (United Kingdom)

Square-wave oscillations exhibiting different plateau lengths have been observed experimentally by investigating an electro-optic oscillator. In a previous study, we analysed the model delay differential equations and determined an asymptotic approximation of the two plateaus. In this paper, we concentrate on the fast transition layers between plateaus and show how they contribute to the total period. We also investigate the bifurcation diagram of all possible stable solutions. We show that the square waves emerge from the first Hopf bifurcation of the basic steady state and that they may coexist with stable low-frequency periodic oscillations for the same value of the control parameter.

Weicker L; Erneux T; D'Huys O; Danckaert J; Jacquot M; Chembo Y; Larger L

2013-01-01

382

A time-dependent semiclassical wavepacket method using a fast Fourier transform (FFT) algorithm  

International Nuclear Information System (INIS)

A new semiclassical propagator based on a local expansion of the potential up to second order around the moving center of the wavepackt is proposed. Formulas for the propagator are derived and the implementation using grid and fast Fourier transform (FFT) methods is discussed. The semiclassical propagator can be improved up to the exact quantum mechanical limit by including anharmonic corrections using a split operator approach. Preliminary applications to the CH3I photodissociation problem show the applicability and accuracy of the proposed method. (orig.)D.

1991-01-01

383

Fast time resolution charge-exchange measurements during the fishbone instability in the poloidal divertor experiment  

International Nuclear Information System (INIS)

Measurements of fast ion losses due to the fishbone instability during high ?/sub T/q neutral beam heated discharges in the Poloidal Divertor Experiment have been made using two new vertical-viewing charge-exchange analyzers. The measurements show that the instability has an n=1 toroidal mode number, and that it ejects beam ions in a toroidally rotating beacon directed outward along a major radius. Observations of ejected ions with energies up to twice the beam injection energy at R approx. = R0 + a indicate the presence of a non-?-conserving acceleration mechanism

1984-01-01

384

Collecting response times using Amazon Mechanical Turk and Adobe Flash.  

Science.gov (United States)

Crowdsourcing systems like Amazon's Mechanical Turk (AMT) allow data to be collected from a large sample of people in a short amount of time. This use has garnered considerable interest from behavioral scientists. So far, most experiments conducted on AMT have focused on survey-type instruments because of difficulties inherent in running many experimental paradigms over the Internet. This study investigated the viability of presenting stimuli and collecting response times using Adobe Flash to run ActionScript 3 code in conjunction with AMT. First, the timing properties of Adobe Flash were investigated using a phototransistor and two desktop computers running under several conditions mimicking those that may be present in research using AMT. This experiment revealed some strengths and weaknesses of the timing capabilities of this method. Next, a flanker task and a lexical decision task implemented in Adobe Flash were administered to participants recruited with AMT. The expected effects in these tasks were replicated. Power analyses were conducted to describe the number of participants needed to replicate these effects. A questionnaire was used to investigate previously undescribed computer use habits of 100 participants on AMT. We conclude that a Flash program in conjunction with AMT can be successfully used for running many experimental paradigms that rely on response times, although experimenters must understand the limitations of the method. PMID:23670340

Simcox, Travis; Fiez, Julie A

2013-05-14

385

A "package solution" fast track program can reduce the diagnostic waiting time in head and neck cancer  

DEFF Research Database (Denmark)

In 2007, a fast track program for patients with suspicion of head and neck cancer (HNC) was introduced in Denmark to reduce unnecessary waiting time. The program was based on so called "package solutions" including pre-booked slots for outpatient evaluation, imaging, and diagnostic surgical procedures. The purpose of this study is to present a model for fast track handling of patients suspicious of cancer in the head and neck region and to evaluate the effect of implementation on the diagnostic work up time. Patients with suspicion of HNC referred to the same university department of ENT Head and Neck Surgery during three comparable time intervals 2006-2007, 2007-2008, and 2011-2012 (groups 1-3) were investigated. We recorded the time from patient referral, to first consultation and final diagnosis. The first interval was before initiation of the "package solution", the second just after the introduction, and the third interval represents the current situation. The median time from referral to first consultation was reduced from eight calendar days in group 1 to only one day in groups 2 and 3 (p 

Sorensen, Jesper Roed; Johansen, JØrgen

2013-01-01

386

Processes in current sheets responsible for fast energy conversion in the magnetospheric collisionless plasma  

CERN Multimedia

Dynamics of the magnetospheric plasma configuration intrinsically features intermittent slow and fast phases. The fast transition is a nonlinear process, loss of equilibrium which ends up the slow quasi-static evolution. The process is analysed as a dynamical bifurcation. It appears when marginal stability state is reached in the course of that evolution, either for tearing mode or for ballooning mode disturbances. The resulting force imbalance leads to spontaneous formation of nonlinear kinetic thin current structures. Those are either a pair of slow collisionless shocks or a specific anisotropic thin current sheet embedded in a thicker plasma sheet structure. Both are the sites of intense energy conversion, and they implement fast magnetic reconnection in the magnetospheric collisionless plasma.

Kropotkin, Alexey

2013-01-01

387

Total and pathogenic Vibrio parahaemolyticus in shrimp: fast and reliable quantification by real-time PCR.  

UK PubMed Central (United Kingdom)

Vibrio parahaemolyticus is found in aquatic environments and is the leading cause of gastroenteritis due to seafood consumption worldwide. We evaluated a quantitative real-time PCR (Q-PCR) assay with hydrolysis probes, to determine whether this method could be used for the efficient counting of total, tdh and trh-positive V. parahaemolyticus in shrimps. We assessed the specificity of this assay, using 62 strains from 12 non target bacterial species of the Vibrio, Photobacterium, Shewanella and Aeromonas genera. Only V. parahaemolyticus with the appropriate target gene generated a fluorescent signal. We assessed the robustness of this assay, by analyzing spiked shrimps by Q-PCR and traditional culture methods, using most probable number (MPN)-PCR. After a 6h enrichment period, the assay successfully detected total and pathogenic V. parahaemolyticus in shrimps samples spiked with less than 5 V. parahaemolyticuscells/g of shrimp. The Q-PCR results obtained were compared with those obtained by most probable number (MPN)-PCR format. An excellent correlation between the two methods was observed in all cases (R² > 0.9742). The application of this Q-PCR assay to 85 natural shrimp samples also resulted in the successful quantification of V. parahaemolyticus in this matrix, and the counts obtained were correlated with those obtained by (MPN)-PCR (P=0.2598). Thus, this rapid and sensitive Q-PCR can be used to quantify V. parahaemolyticus in natural shrimp samples. This assay could be proposed, in response to the demands of the European Commission, as a tool for testing for the presence of vibrios in crustaceans, making it possible to legislate in this domain.

Robert-Pillot A; Copin S; Gay M; Malle P; Quilici ML

2010-10-01

388

High-fat diet feeding alters metabolic response to fasting/non fasting conditions. Effect on caveolin expression and insulin signalling  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The effect of food intake on caveolin expression in relation to insulin signalling was studied in skeletal muscle and adipocytes from retroperitoneal (RP) and subcutaneous (SC) adipose tissue, comparing fasted (F) to not fasted (NF) rats that had been fed a control or high-fat (HF) diet for 72 days. Methods Serum glucose was analysed enzymatically and insulin and leptin by ELISA. Caveolins and insulin signalling intermediaries (IR, IRS-1 and 2 and GLUT4) were determined by RT-PCR and western blotting. Caveolin and IR phosphorylation was measured by immunoprecipitation. Data were analysed with Mann-Whitney U test. Results High-fat fed animals showed metabolic alterations and developed obesity and insulin resistance. In skeletal muscle, food intake (NF) induced activation of IR and increased expression of IRS-2 in control animals with normal metabolic response. HF animals became overweight, hyperglycaemic, hyperinsulinemic, hyperleptinemic and showed insulin resistance. In skeletal muscle of these animals, food intake (NF) also induced IRS-2 expression together with IR, although this was not active. Caveolin 3 expression in this tissue was increased by food intake (NF) in animals fed either diet. In RP adipocytes of control animals, food intake (NF) decreased IR and IRS-2 expression but increased that of GLUT4. A similar but less intense response was found in SC adipocytes. Food intake (NF) did not change caveolin expression in RP adipocytes with either diet, but in SC adipocytes of HF animals a reduction was observed. Food intake (NF) decreased caveolin-1 phosphorylation in RP but increased it in SC adipocytes of control animals, whereas it increased caveolin-2 phosphorylation in both types of adipocytes independently of the diet. Conclusions Animals fed a control-diet show a normal response to food intake (NF), with activation of the insulin signalling pathway but without appreciable changes in caveolin expression, except a small increase of caveolin-3 in muscle. Animals fed a high-fat diet develop metabolic changes that result in insulin signalling impairment. In these animals, caveolin expression in muscle and adipocytes seems to be regulated independently of insulin signalling.

Gómez-Ruiz Ana; Milagro Fermín I; Campión Javier; Martínez J Alfredo; de Miguel Carlos

2011-01-01

389

An Efficient Approach to Improve Response Time in Multibiometric Patterns Retrieval from Large Database  

Directory of Open Access Journals (Sweden)

Full Text Available Biometric technologies are automated methods of verifying or recognizing the identity of a livingperson based on a physiological or behavioural characteristics. In a biometric identification system, theidentity corresponding to the input data (probe/investigation) is typically determined by comparing it againstthe templates of all identities in a database (gallery).Exhaustive/in-depth matching against a large number ofidentities increases the response time of the system and may also reduce the accuracy of identification. Oneway to reduce the response time is by designing biometric templates that allow for rapid matching. Analternative approach is to limit the number of identities against which matching is performed based oncriteria that are fast to evaluate. In the Existing system the search space is reduced by partitioning thedatabase into several bins. Following such binning, the biometric database will be partitioned such that thetemplates in each bin are similar and correspond to some natural or statistical class. In case of the traditional1: N comparisons for identification, the time needed for the system would be to determine the distancebetween the test template and the N templates in database. Thus the total time needed in such a case could begiven as: Q (N). The proposed work focuses on reducing the search space using Gittins index algorithm andalso improves the accuracy of identification.

S. Balgani; S. Sangeetha?

2013-01-01

390

Effect of treatment time on low temperature plasma nitriding of stainless steel by saddle field neutral fast atom beam source  

Energy Technology Data Exchange (ETDEWEB)

Recent research carried out in laboratories showed that Saddle field neutral fast atom beam source is a promising method for nitriding of stainless steel. In the present work, the effect of treatment time on the microstructural and mechanical properties of plasma-nitrided stainless steel sample was investigated by this new method. Plasma nitriding was carried out at 420 deg. C and at a pressure of 0.1 Pa for a time range of 1 to 12 h. SEM-EDX, microhardness tests, optical microscopy and X-ray diffraction (XRD) were used to evaluate the mechanical and structural properties of the nitrided layer. It was found that nitriding time has a pronounced effect on the structural and mechanical properties of low-temperature plasma-nitrided samples and produced a precipitation-free thin hard nitrided layer within a short processing time.

Rahman, Mahfujur [NCPST and MPRC, Dublin City University, Dublin-9 (Ireland)]. E-mail: md.rahman5@mail.dcu.ie; Hashmi, M.S.J. [NCPST and MPRC, Dublin City University, Dublin-9 (Ireland); School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin-9 (Ireland)

2006-09-25

391

Effect of treatment time on low temperature plasma nitriding of stainless steel by saddle field neutral fast atom beam source  

International Nuclear Information System (INIS)

[en] Recent research carried out in laboratories showed that Saddle field neutral fast atom beam source is a promising method for nitriding of stainless steel. In the present work, the effect of treatment time on the microstructural and mechanical properties of plasma-nitrided stainless steel sample was investigated by this new method. Plasma nitriding was carried out at 420 deg. C and at a pressure of 0.1 Pa for a time range of 1 to 12 h. SEM-EDX, microhardness tests, optical microscopy and X-ray diffraction (XRD) were used to evaluate the mechanical and structural properties of the nitrided layer. It was found that nitriding time has a pronounced effect on the structural and mechanical properties of low-temperature plasma-nitrided samples and produced a precipitation-free thin hard nitrided layer within a short processing time

2006-09-25

392

Prior exercise reduces fast-start duration and end-spurt magnitude during cycling time-trial.  

UK PubMed Central (United Kingdom)

We examined the pacing strategy and the magnitude of the end spurt during a 200-kJ cycling time trial performed 12-14 h after an exercise protocol designed to reduce muscle glycogen content. 9 physically-active men performed 5 familiarization sessions and 2 experimental 200-kJ time trials in either a control condition (CON) or after an exercise protocol performed the previous evening that was designed to induce muscle glycogen depletion (EP). Mean total time was faster and power output was higher in the CON than in the EP (P<0.01). A fast-start was maintained until the 50-kJ section in CON, but only the 25-kJ section for EP (P<0.05). The power outputs during the 50-, 150- and 200-kJ sections, and the magnitude of the end-spurt, were significantly higher for the CON than for the EP condition (P<0.05). There was no significant difference in the rating of perceived exertion (overall feeling and feeling in legs) between conditions. In conclusion, a protocol designed to decrease muscle glycogen stores reduced the duration of the fast-start and the magnitude of the end spurt during a 200-kJ cycling time trial, impairing the overall performance.

Lima-Silva AE; Correia-Oliveira CR; Tenorio L; Melo AA; Bertuzzi R; Bishop D

2013-08-01

393

The comparative assessment of different echo time in 3D heavily T2-weighted fast spin-echo MR sialography  

International Nuclear Information System (INIS)

Objective: To chose the best echo time of 3D MR sialography on a Philips 1.5-T unit by comparative study of different echo time. Methods: Ten volunteers without salivary gland diseases were included in this study. SENSE-FLEX-M coil was used in every volunteer. Repitated time and other scan parameters were fixed and serial heavily T2-weighted fast spin echo sequences of different echo time and signal intensity of salivary ducts and background tissue were measured in 6 different regions of interest. Contrast to noise ratio (CNR) was measured and compared. Results: The salivary gland duets and its peripheral branches can be displayed on images of MR sialography in all volunteers. The CNR of parotid gland duct using TE 500 ms was statistically lower than those using other TEs (P0.05). The CNR of submandibular gland duet using TE 800 ms was statistically higher than those using other TEs(P0.05). Conclusion: It is the best choice for 3D heavily T2-weighted fast spin echo MR Sialography using TE 800 ms. (authors)

2008-01-01

394

LHCb: Beam and Background Monitoring and the Upgrade of the Timing and Fast Control System of the LHCb experiment at CERN  

CERN Document Server

The LHCb experiment at CERN is preparing for first real data taking, foreseen by the end of the year 2009 with the start-up of the LHC. A large amount of work of commissioning, tests and improvements of the full detector has been done in order to optimize its performance. During my first year as a Doctoral Student at CERN, I have been working on the timing and readout control of the LHCb experiment in the frame of the LHCb Online group. The group is responsible for the full data acquisition of the LHCb experiment, from the Front-End Electronics (FEE) to the storage of the data for offline analysis, as well as the Timing and Fast Control (TFC) system. The latter controls and distributes centrally timing and trigger information, as well as synchronous and asynchronous commands to the readout system. It is also responsible for receiving and adjusting the bunch and orbit clocks of the LHC machine and distributing it to the electronics of the whole experiment. It is of vital importance to assure that the timing o...

Alessio, F

2009-01-01

395

TDC-1/TDC-2. Full custom ASICs for fast time encoding; TDC-1/TDC-2. Circuits integres d`evaluation pour le codage rapide du temps  

Energy Technology Data Exchange (ETDEWEB)

Following the pre-diffused fast time encoder CRT-C, the Electronics Department has begun the design of a full custom fast encoder. We have realized an estimation circuit in 0.8 {mu} BiCMOS technology performing 3 multiphase VCO with 125 ps between phases. (author) 1 fig.

Wanlin, E. [Services Techniques, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

1999-11-01

396

Time response measurements of pressure sensors using pink noise technique  

International Nuclear Information System (INIS)

[en] This work presents an experimental setup for Pink Noise method application on pressure transmitters' response times. The Pink Noise method consists on injecting artificial pressure noise into the pressure transmitter. The artificial pressure noise is generated using a current-to-pressure (I-to-P) converter, which is driven by a random noise signal generator. The output pressure transmitter noise is then analyzed using conventional Noise Analysis Technique. Noise signals may be interpreted using spectral techniques or empirical time series models. The frequency domain method consists of evaluating the Power Spectral Density (PSD) function. The information needed for time constant estimation can be obtained by fitting an all-pole transfer function to this power spectral density. (author)

2009-10-02

397

Sensitivity and response time improvements in millimeter-wave spectrometers  

Energy Technology Data Exchange (ETDEWEB)

A new version of a microwave spectrometer for the detection of gaseous pollutants and other atmospheric constituents is described. The spectrometer, which operates in the vicinity of 70 GHz, employs a Fabry-Perot resonator as a sample cell and uses superhetrodyne detection for high sensitivity. The spectrometer has been modified to incorporate a frequency doubler modulated at 30 MHz to permit operation with a single Gunn oscillator source. As a result, faster response time and somewhat greater sensitivity are obtained. The spectrometer is capable of detecting a minimum concentration of 1 ppM of SO/sub 2/ diluted in air with a 1 second time constant. For OCS diluted in air, the minimum detectable concentration is 800 ppB and with a 10 second time constant 300 ppB.

Kolbe, W.F.; Leskovar, B.

1980-09-01

398

Fasting levels of ghrelin covary with the brain response to food pictures.  

UK PubMed Central (United Kingdom)

Ghrelin figures prominently in the regulation of appetite in normal-weighed individuals. The apparent failure of this mechanism in eating disorders and the connection to addictive behavior in general demand a deeper understanding of the endogenous central-nervous processes related to ghrelin. Thus, we investigated processing of pictures showing palatable food after overnight fasting and following a standardized caloric intake (i.e. a 75-g oral glucose tolerance test) using functional magnetic resonance imaging and correlated it with blood plasma levels of ghrelin. Twenty-six healthy female and male volunteers viewed food and control pictures in a block design and rated their appetite after each block. Fasting levels of ghrelin correlated positively with food-cue reactivity in a bilateral network of visual processing-, reward- and taste-related regions, including limbic and paralimbic regions. Notably, among those regions were the hypothalamus and the midbrain where ghrelin receptors are densely concentrated. In addition, high fasting ghrelin levels were associated with stronger increases of subjective appetite during the food-cue-reactivity task. In conclusion, brain activation and subjective appetite ratings suggest that ghrelin elevates the hedonic effects of food pictures. Thereby, fasting ghrelin levels may generally enhance subjective craving when confronted with reward cues.

Kroemer NB; Krebs L; Kobiella A; Grimm O; Pilhatsch M; Bidlingmaier M; Zimmermann US; Smolka MN

2013-09-01

399

A single phase voltage regulator module (VRM) with stepping inductance for fast transient response  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A single-phase fast transient converter topology with stepping inductance is proposed. The stepping inductance method is implemented by replacing the conventional inductor in a buck converter by two inductors connecting in series. One has large inductance and the other has small inductance. The indu...

Lu, DDC; Liu, JCP; Poon, FNK; Pong, BMH

400

TREAT fast-neutron hodoscope: improvements in time and mass resolution of fuel motion  

International Nuclear Information System (INIS)

The fast-neutron hodoscope at the Transient Reactor Test Facility detects fuel motion in thick opaque capsules during in-core destructive transient tests. Counts from several hundred detectors, each with rates up to a megahertz, are collected at intervals as short as a millisecond for up to tens of seconds. The large amount of data must be decoded, normalized, represented in suitable forms, and analyzed. A computer-controlled magnet disk data acquisition system has been installed which provides shorter data collection intervals, simplifies decoding, and permits immediate data analysis. Data normalizations and representations have been developed which significantly increase the dynamic range, yield sensitive quantitative indications of fuel mass motion, and render the data intuitively comprehensible. The improved hodoscope system performance level is demonstrated by results from a recent transient test, Pinex-2, which show the quantitative evolution of fuel mass motion from 1515 MW peak reactor power through a 1 MW post-scram radiation level

1978-10-20

 
 
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