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1

Fast-Response-Time Shape-Memory-Effect Foam Actuators  

Science.gov (United States)

Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating the need for welding, adhesives, or mechanical crimping. Inexpensive net-shape processing was used, which reduces the cost of the actuator by over a factor of 10 over nonporous TiNi made by hot drawing of tube or electrical discharge machining. By forming the alloy as an open-celled foam, the surface area for heat transfer is dramatically increased, allowing for much faster response times. The technology also allows for netshape fabrication of the actuator, which allows for structural connections to be integrated into the actuator material, making these actuators significantly less expensive. Commercial applications include actuators for concepts such as the variable area chevron and nozzle in jet aircraft. Lightweight tube or rod components can be supplied to interested parties.

Jardine, Peter

2010-01-01

2

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

3

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

Science.gov (United States)

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. PMID:24104671

Ren, Hongwen; Xu, Su; Wu, Shin-Tson

2013-08-15

4

Time-resolved flow measurements with fast-response aerodynamic probes in turbomachines  

Energy Technology Data Exchange (ETDEWEB)

A better understanding of unsteady flow phenomena encountered in rotor-stator interactions is a key to further improvements in turbomachinery. Besides CFD methods yielding 3D flow field predictions, time-resolving measurement techniques are necessary to determine the instantaneous flow quantities of interest. Fast-response aerodynamic probes are a promising alternative to other time-resolving measurement techniques such as hot-wire anemometry or laser anemometry. This contribution gives an overview of the fast-response probe measurement technique, with the emphasis on the total system and its components, the development methods, the operation of such systems and the data processing requirements. A thorough optimisation of all system components (such as sensor selection and packaging, probe tip construction, probe aerodynamics and data analysis) is the key of successful development. After description of the technique, examples of applications are given to illustrate its potential. Some remarks will refer to recent experiences gained by the development and application of the ETH FRAP{sup reg} system. (Author)

Kupferschmied, Peter; Koeppel, Pascal; Gizzi, William; Roduner, Christian; Gyarmathy, Georg [ETH Zurich, Inst. of Energy Technology, Zurich (Switzerland)

2000-07-01

5

Fast timing discriminator  

International Nuclear Information System (INIS)

The processing of pulses with very fast risetimes for timing purposes involves many problems because of the large equivalent bandwidths involved. For pulses with risetimes in the 150 ps range (and full widths at half maximum (FWHM) of 400 ps) bandwidths in excess of 1GHz are required. Furthermore, these very narrow pulses with current amplitudes as small as 1 mA carry very small charges (<10"-"1"2 coulomb), therefore, requiring very sensitive trigger circuits. The difficulty increases when timing characteristics in the picosecond range are sought especially when a wide input signal amplitude range causes a time-walk problem. The fast timing discriminator described has a time-walk of approximately +-75 ps over the input signal range from 80 mV to 3V. A schematic of the discriminator is included, and operation and performance are discussed

1977-01-01

6

Time-resolved entropy measurements using a fast response entropy probe  

International Nuclear Information System (INIS)

This paper describes a recently developed miniature fast response entropy probe and its application in the turbomachinery facilities at ETH Zurich. The development of the probe is motivated by the need to more clearly document the loss generation mechanisms in the harsh environment of turbomachines. The probe is comprised of a piezoresistive sensor and a pair of thin-film gauges that measure the unsteady pressure and temperature, respectively. The unsteady relative entropy can thus be determined. The design, manufacture and calibration of the probe are first presented in detail. Its application to detail the unsteady entropy field, and associated losses, in a centrifugal compressor, axial turbine and film cooling flows are then described

2008-11-01

7

Conversion efficiency and time response of phosphors for fast X-ray imaging with synchrotron radiation  

International Nuclear Information System (INIS)

X-ray imagers meeting the requirements of synchrotron radiation experiments are being developed at the ESRF. The phosphors used in these imagers will determine their final properties, and particularly the time response and dynamic range. The conversion efficiencies for low energy X-rays, and mainly the time behaviour of different compounds are presented in this article. Detectors based on X-ray image intensifiers (XRII) using CsI:Na as the input converter and P46 as the output screen, optically coupled to CCD cameras will make it possible to acquire images with a frame rate up to 1000 images/s, and a dynamic range of more than 1000. (orig.)

1993-03-10

8

Fast water oil spill response  

International Nuclear Information System (INIS)

Of the many manuals currently available for oil spill response, few have any information on fast-water conditions even though just more than half of all oil spilled by volume in the United States between 1992 and 1997 happened in waterways with currents exceeding one knot. The Coast Guard recognized the absence of standard terminology that could be used for fast-water responses. For that reason, an initiative was undertaken to create a document that addresses only fast-water issues. Two major parts of the project were to provide information on deployment strategies and techniques to identify equipment that could improve recovery capabilities where existing systems do not work well. This paper described field demonstrations where boom deflectors and boom vanes were used. Efforts to increase the capability of booms and skimmers were also described. A field guide was developed for training and response purposes for spills in fast-water which makes it possible for on-scene commanders and area supervisors to define techniques and terminology for responders in the field. It is particularly useful for Coast Guard Marine Safety Units when working with Coast Guard operational units during an emergency response. 20 refs., 4 figs

2002-06-11

9

The time-walk of analog constant fraction discriminators using very fast scintillator detectors with linear and non-linear energy response  

International Nuclear Information System (INIS)

The electronic ?–? fast timing technique allows for direct nuclear lifetime determination down to the few picoseconds region by measuring the time difference between two coincident ?-ray transitions. Using high resolution ultra-fast LaBr3(Ce) scintillator detectors in combination with the recently developed mirror symmetric centroid difference method, nuclear lifetimes are measured with a time resolving power of around 5 ps. The essence of the method is to calibrate the energy dependent position (centroid) of the prompt response function of the setup which is obtained for simultaneously occurring events. This time-walk of the prompt response function induced by the analog constant fraction discriminator has been determined by systematic measurements using different photomultiplier tubes and timing adjustments of the constant fraction discriminator. We propose a universal calibration function which describes the time-walk or the combined ?–? time-walk characteristics, respectively, for either a linear or a non-linear amplitude versus energy dependency of the scintillator detector output pulses.

2012-08-21

10

Fast-Response Liquid Crystal Microlens  

Directory of Open Access Journals (Sweden)

Full Text Available Electrically tunable liquid crystal microlenses have attracted strong research attention due to their advantages of tunable focusing, voltage actuation, low power consumption, simple fabrication, compact structure, and good stability. They are expected to be essential optical devices with widespread applications. However, the slow response time of nematic liquid crystal (LC microlenses has been a significant technical barrier to practical applications and commercialization. LC/polymer composites, consisting of LC and monomer, are an important extension of pure LC systems, which offer more flexibility and much richer functionality than LC alone. Due to the anchoring effect of a polymer network, microlenses, based on LC/polymer composites, have relatively fast response time in comparison with pure nematic LC microlenses. In addition, polymer-stabilized blue phase liquid crystal (PS-BPLC based on Kerr effect is emerging as a promising candidate for new photonics application. The major attractions of PS-BPLC are submillisecond response time and no need for surface alignment layer. In this paper, we review two types of fast-response microlenses based on LC/polymer composites: polymer dispersed/stabilized nematic LC and polymer-stabilized blue phase LC. Their basic operating principles are introduced and recent progress is reviewed by examples from recent literature. Finally, the major challenges and future perspectives are discussed.

Su Xu

2014-06-01

11

The high contrast ratio and fast response time of a liquid crystal display lit by a carbon nanotube field emission backlight unit  

International Nuclear Information System (INIS)

We report on the fabrication of a carbon nanotube field emission backlight unit (CNT-BLU) and its application for liquid crystal displays (LCD). The CNT-BLU was operated with locally controllable luminance and impulse-type scanning. The local luminance control, which is based on a very small block size of 1 cm2, consisted of local dimming and local brightening. This resulted in the contrast ratio of the LCD-TV to be as high as 300 000:1. A fast response time of ?5.7 ms was also achieved from the LCD-TV lit by CNT-BLU, originating from the impulse-type scanning. In addition, the CNT-BLU showed long-term emission stability and high luminance uniformity

2008-06-11

12

High sensitivity and fast response and recovery times in a ZnO nanorod array/p-Si self-powered ultraviolet detector  

Science.gov (United States)

High quality, vertically aligned ZnO nanorods were grown on a silicon substrate, using microwave-assisted chemical bath deposition with poly (vinyl alcohol)-Zn(OH)2 nanocomposites as seed layer. The structure and surface morphology of the prepared ZnO nanorod arrays were characterized using X-ray diffraction and scanning electron microscopy. The optical properties were assessed using photoluminescence measurements; the results showed a high-intensity UV peak, and a lower intensity, broader visible peak. Upon exposure to 395 nm light at a zero-bias voltage, the UV detector showed a high sensitivity of 8000% and fast response and recovery times of 25 and 22 ms, respectively.

Hassan, J. J.; Mahdi, M. A.; Kasim, S. J.; Ahmed, Naser M.; Abu Hassan, H.; Hassan, Z.

2012-12-01

13

LCD response time estimation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Techniques to reduce LCD motion blur are extensively used in industry and they depend on an inherent LCD parameter: response time. However, normative response time is not a sufficient reference to improve LCD performance. Rather, all the gray-to-gray response times quantities are required to obtain a good improvement quality. Consequently, we propose a novel LCD model to simulate as well as compute gray-to-gray transitions (response time and behavior) from a reduced measurement set.

Adam, Pierre; Bertolino, Pascal; Chassery, Jean-marc; Lebowsky, Fritz

2006-01-01

14

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

15

Fast response bolometer for high temperature plasma  

International Nuclear Information System (INIS)

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

16

The response of mouse skin to fractionated doses of fast neutrons (66 Me Vp-Be) with variable interfraction and overall treatment times  

International Nuclear Information System (INIS)

Beam availability for neutron therapy at the National Accelerator Centre at Faure, South Africa is such that treatment fractions are given at irregularly spaced intervals. Such treatment scheduling may not be optimal. Investigations were made using the acute skin reaction of the mouse foot to determine the effect of different numbers of regularly and irregularly spaced fractions of p(66)/Be neutrons. Assessment of results was both by average skin reaction and by ED50 values for the incidence of moist desquamation as established by probit analysis. Different numbers of fractions (between 6 and 11) and different times between fractions did not appear to affect the mouse foot response significantly when fractionation was completed within 11 days, i.e. before repopulation began to have an effect. When overall treatment times were longer than 11 days, the mouse foot responses to 6 and 9 fractions with variable interfraction times were similar, provided the overall treatment times were the same and the fractions were at least 24 h apart. The ?/? ratio was 87±27 (SE) Gy for the early response of the BALB/c mouse foot skin to p(66)/Be neutrons. The response of mouse skin to fractionated p(66)/Be neutrons was independent of fraction number or interfraction time, provided that the overall treatment time was the same. (orig.)

1995-01-01

17

Fast response stainless steel sodium thermocouple  

International Nuclear Information System (INIS)

The design and construction of SS-Na thermocouple to be used in pool type reactors are described. The distinguishing feature of SS-Na thermocouple is that they are very fast responding type, (instantaneous measurement), since the temperature sensitive points or functions are just on the outer surface of the tip of the SS well, and the sodium itself is already carrying the heat. This instantaneous response makes its application very useful in detecting the transient temperature fluctuations in sodium. Various tests on these types of thermocouples have been conducted to evaluate their response characteristics, and their suitability for application to sodium flow measurement. (K.B.)

1976-12-23

18

Fast reactor response matrix nodal analysis  

International Nuclear Information System (INIS)

A general nodal coupling scheme, including a number of common options as special cases, under a response matrix form, has been utilized within the one-group light water reactor code SIMULATE. In this work an extension to multigroup was developed and implemented in the nodal test code SIMMG. It was tested to demonstrate that the assumptions associated with the extension of the formalism were satisfactory for fast reactor situations. A number of nodal options were applied to a range of cases involving configurations of importance in fast reactors. Among those options: coarse mesh diffusion theory, modified coarse mesh diffusion theory, nodal expansion method, to second order, and to fourth order, one particular options, reflection based coarse mesh theory, has yielded consistently better results than the other methods considered. The results obtained were compared to fine mesh calculations, using the code 2DB, and they show that nodal methods, in the response matrix form used in the Simulate Multigroup formalism, may be applied to fast reactor problems with very good results and savings

1982-01-01

19

Time of flight fast neutron radiography  

Energy Technology Data Exchange (ETDEWEB)

Neutron radiography with fast or thermal neutrons is a standard technique for non-destructive testing (NDT). Here we report results for fast neutron radiography both as an adjunct to pulsed fast neutron analysis (PFNA) and as a stand-alone method for NDT. PFNA is a new technique for utilizing a collimated pulsed neutron beam to interrogate items and determine their elemental composition. By determining the time of flight for gamma-rays produced by (n,n` gamma X) reactions, a three dimensional image can be produced. Neutron radiography data taken with the same beam provides an important constraint for image reconstruction, and in particular is important in inferring the amount of hydrogen within the interrogated item. As a stand-alone device, the radiography measurement can be used to image items as large as cargo containers as long as their density is not too high. The use of a pulsed beam gives the further advantage of a time of flight measurement on the transmitted neutrons. By gating the radiography signal on the time of flight appropriate to the energy of the primary neutrons, most build-up from scattered neutrons can be eliminated. The pulsed beam also greatly improves the signal to background and extends the range of the neutron radiography. Simulation results will be presented which display the advantage of this constraint in particular for statistically limited data. Experimental results will be presented which show some of the limitations likely in a PFNA system utilizing neutron radiography data. Experimental and simulation results will demonstrate possible uses for this type of radiographic data in identifying contraband substances such as drugs. (orig.).

Loveman, R. [Science Applications Int. Corp., Santa Clara, CA (United States); Bendahan, J. [Science Applications Int. Corp., Santa Clara, CA (United States); Gozani, T. [Science Applications Int. Corp., Santa Clara, CA (United States); Stevenson, J. [Science Applications Int. Corp., Santa Clara, CA (United States)

1995-05-01

20

Magnetostrictive actuators with large displacement and fast response  

International Nuclear Information System (INIS)

This paper presents the development of a giant magnetostrictive actuator (GMA) with large displacement and fast response. An elliptical flexure hinge lever amplification structure is designed and applied in the GMA. The finite element method is adopted for analyzing and optimizing flexure hinge geometry. Furthermore, the coil and magnetic circuit are studied to improve the driving system. Static and dynamic performances of the GMA are tested. As a result, displacement output amplification ratio can be 2.68 times in the static test. The dynamic performance testing indicates that the GMA with amplification structure can achieve a steady output on average of 140 µm between 0 and 130 Hz driving by 240 Oe, and the time response is 0.6 ms. These results show that large displacement and fast response are obtained simultaneously. (paper)

2012-05-01

 
 
 
 
21

Fast Responses in L/H transition  

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). A small fraction of non-local component in the heat flux is found to be very effective in modifying the response against L/H transition. The transient features of the transport property, which are observed in the response of heat pulse propagation, are qualitatively reproduced by the transport simulations based on this model. (author)

2001-05-01

22

Fast responses in L/H transition  

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). A small fraction of non-local component in the heat flux is found to be very effective in modifying the response against L/H transition. The transient features of the transport property, which are observed in the response of heat pulse propagation, are qualitatively reproduced by the transport simulations based on this model. (author)

1999-12-01

23

Fast responses in L-H transitions  

International Nuclear Information System (INIS)

An equation which includes a non-local effect in the heat flux is introduced to study transient transport phenomena. A non-local heat flux, which is expressed in terms of an 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 L mode to H mode. A small fraction of non-local component in the heat flux is found to be very effective in modifying the response against an L-H transition. The transient features of the transport property, which are observed in the response of heat pulse propagation, are qualitatively reproduced by the transport simulations based on this model. (author)

1999-11-01

24

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)

1962-03-01

25

A constant fraction differential discriminator for use in a fast-fast timing system  

International Nuclear Information System (INIS)

A constant fraction differential discriminator used in a fast-fast timing system is described. The discriminator performs both timing and energy range selection funcitons. The time walk is 120 ps for 1 ns risetime input signal from -50 mV to -5 V. The time resolution as a function of dynamic range in a fast-fast timing system is given. The FWHM is 201 ps when measured with 1.4:1 dynamic range

1986-01-01

26

Concomitant Effects of Ramadan Fasting and Time-Of-Day on Apolipoprotein AI, B, Lp-a and Homocysteine Responses during Aerobic Exercise in Tunisian Soccer Players  

Science.gov (United States)

Objective To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT). Design Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER). Setting For each session, subjects performed the YYIRT, and blood samples were taken before and 3-min after the test for biochemical measures. Participants Fifteen soccer players. Main Outcome Measures Total distance during the YYIRT, core temperature, body composition, dietary intakes, lipid (HDL-C, LDL-C, Apo-AI, B and Lp-a) and inflammatory (hs-CRP and Hcy) profiles. Results Performances during the YYIRT were higher in the evening than the morning BR (P < 0.05), but this fluctuation was not observed during RF. Moreover, LDL-C, ApoB, and Lp-a were stable throughout the daytime BR. However, during RF, they decreased at 17:00 h (P < 0.05). Likewise, HDL-C and Apo-AI increased after the exercise and were higher at 17:00 h BR (P < 0.001). Moreover, these parameters increased during RF (P < 0.01). Furthermore, Hcy and hs-CRP increased during the exercise (P < 0.01) with higher evening levels BR. During ER, the diurnal pattern of Hcy was inversed (P < 0.001). Conclusions This study concluded that caloric restriction induced by RF seems to ameliorate lipid and inflammatory markers of cardiovascular health during intermittent exercise performed in the evening.

Hammouda, Omar; Chtourou, Hamdi; Aloui, Asma; Chahed, Henda; Kallel, Choumous; Miled, Abdelhedi; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

2013-01-01

27

Time-resolved and time-integrated radiography of fast reactor fuel elements  

International Nuclear Information System (INIS)

The fast-reactor safety program has some unusual requirements in radiography. Applications may be divided into two areas: time-resolved or time-integrated radiography. The fast-neutron hodoscope has supplied all recent time-resolved cineradiographic in-pile fuel-motion data, and various x-ray and photographic techniques have been used for out-of-pile experiments. Thick containers and the large number of radioactive fuel pins involved in safety research have been responsible for some nonconventional applications of time-integrated radiography of stationary objects. Hodoscopes record fuel-motion during transient experiments at the TREAT reactor in the United States and CABRI in France. Other special techniques have been under development for out-of-pile nondestructive radiography of fuel element subassemblies, including fast-neutron and gamma-ray tomographic methods

1981-10-15

28

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)

2001-03-01

29

Testing Time Dilation on Fast Ion Beams  

International Nuclear Information System (INIS)

We report the status of an experimental test of time dilation in Special Relativity. This is accomplished by simultaneously measuring the forward and backward Doppler shifts of an electronic transition of fast moving ions, using high-precision laser spectroscopy. From these two Doppler shifts both the ion velocity ? = v/c and the time dilation factor can be derived. From measurements based on saturation spectroscopy on lithium ions stored at ? = 0.03 and ? = 0.06 in the TSR heavy-ion storage ring, we achieved an upper limit for a O[?2] deviation from Special Relativity of ?? 8x10-8. In recent measurements on a ? = 0.34 Li+ beam in the ESR storage ring we used optical-optical double-resonance spectroscopy which, in combination with the TSR result, gives improved sensitivity on the O[?4] term of ?2 ?1.2x10-5. We discuss current limitations and possible improvements that promise an enhancement of the sensitivity by at least one order of magnitude in the future.

2011-09-23

30

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

31

Characteristics of fast response InSb submillimeter detector  

International Nuclear Information System (INIS)

A highly sensitive, fast responding n-InSb detector for the millimeter and submillimeter region has been fabricated and optimized for use to measure the electron cyclotron emission from tokamak plasmas, in connection with bandpass filters or a rapid scanning Fourier transform spectrometer. The detector element is made of high purity n-type InSb and is in magnetic fields up to 12 kG. The spectral responsivity, response time and noise equivalent power (NEP) of the detector have been measured. The response time of 0.2 ?sec, and NEP of 1.0 x 10-10 W/?H sub(z) at 4.2 K and 8 kG and that of 2.3 x 10-11 W/?H sub(z) at 1.8 K and 10 kG are obtained. These values are useful for the measurements of electron cyclotron emission from tokamak plasmas. (author)

1979-01-01

32

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)

2001-09-10

33

A fast response electrometer for pulse reactor experiments  

International Nuclear Information System (INIS)

This paper clarifies the relation between stability and response speed of an electrometer and then shows a new guard technique and experimental results of the fast response electrometer to which this technique was applied. (Auth.)

1978-06-15

34

Modeling response signal and response time data?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The diffusion model (Ratcliff, 1978) and the leaky competing accumulator model (LCA, Usher & McClelland, 2001) were tested against two-choice data collected from the same subjects with the standard response time procedure and the response signal procedure. In the response signal procedure, a stimulus is presented and then, at one of a number of experimenter-determined times, a signal to respond is presented. The models were fit to the data from the two procedures simultaneously under the assu...

2006-01-01

35

Fast stratocumulus time scale in mixed layer model and large eddy simulation  

Science.gov (United States)

mixed layer model (MLM) and large eddy simulation (LES) are used to analyze the internal response time scales of a stratocumulus-topped boundary layer (STBL). Three separate time scales are identified: a slow time scale associated with boundary layer deepening (several days), an intermediate thermodynamic time scale (approximately 1 day), and a fast time scale (6-12 h) for cloud water path adjustment associated with an internal entrainment-liquid flux (ELF) feedback. The nocturnal DYCOMSII-RF01 case study is used to establish and interpret the previously unidentified fast STBL adjustment time scale with the MLM. The role of the entrainment closure is investigated by repeating the analysis with several different closures. Nearly every closure considered exhibits a fast time scale. Perturbations are applied to the well-mixed CGILS stratocumulus case in both MLM and LES in order to elicit a short time scale response. Purely radiative perturbations do not project strongly onto the fast scale, while perturbations to the free tropospheric humidity do. A 2K surface and atmospheric temperature perturbation also projects strongly onto the fast scale. We show that the ELF adjustment mechanism behind the fast time scale is responsible for much of the steady state liquid water path response in the perturbed case, acting as a cloud-thinning feedback mechanism in a uniformly warmed climate.

Jones, C. R.; Bretherton, C. S.; Blossey, P. N.

2014-03-01

36

New Charge Sensitive Preamplifier with a Fast Timing Signal Output.  

Science.gov (United States)

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 i...

S. Watanabe

1977-01-01

37

Fast optical response to electrical activation in peripheral nerves  

Science.gov (United States)

Complex neuronal structures and interactions make studying fast optical signals associated with brain activation difficult, especially in non-invasive measurements that are further complicated by the filtering effect of the scalp and skull. We have chosen to study fast optical signals in the peripheral nervous system to look at a more simplified biological neuronal structure and a system that is more accessible to non-invasive optical studies. In this study, we recorded spatially resolved electrical and optical responses of the human sural nerve to electrical stimulation. A 0.1 ms electrical stimulation was used to activate the sural nerve. Electrical signals were collected by an electromyogram machine and results showed an electrical response spanning a distance of 8 mm across the nerve. Optical signals were collected by a two-wavelength (690 and 830 nm) near-infrared spectrometer and displayed a characteristic decrease in intensity at both wavelengths. Data were taken at multiple positions and then reproduced five times. The average optical data over the five trials showed an optical signal that was spatially consistent with the electrical response to sural nerve stimulation.

Chen, Debbie K.; Tong, Yunjie; Sassaroli, Angelo; Bergethon, Peter R.; Fantini, Sergio

2007-03-01

38

Fast response, high resolution heterodyne quadrature interferometer  

International Nuclear Information System (INIS)

For measuring the line integral density of plasma in nuclear fusion research, the use of laser interferometers has become common. Especially recently, effort has been exerted toward the use of interferometers as high reliable, automatic, real time density measuring instruments by automating the processing of interference signals. Since interferometers are the effective means to know the macroscopic behavior of plasma, if they can be used conveniently, it can be expected to use them as routine plasma monitors. The authors made for trial and developed an interferometer of quadrature detection type, which can be applied to pinch plasma measurement, by the following improvement. Increase modulation frequency to 60 MHz, expand the band width of a phase detector to twice, and use Tsub(e)O_2 sonic-optical elements of high efficiency. The authors analyzed the response to transient phase change by modeling the action characteristics of the phase detector. This interferometer was applied to the measurement of FRC plasma, and on the basis of the results of measurement, the propriety of the analysis was confirmed. The constitution of the interferometer, its response characteristics, and the application to the measurement of the line integral density of FRC plasma are reported. (Kako, I.)

1985-01-01

39

Polycrystalline CVD diamond detector: Fast response and high sensitivity with large area  

Directory of Open Access Journals (Sweden)

Full Text Available Polycrystalline diamond was successfully used to fabricate a large area (diameter up to 46 mm radiation detector. It was proven that the developed detector shows a fast pulsed response time and a high sensitivity, therefore its rise time is lower than 5 ns, which is two times faster than that of a Si-PIN detector of the same size. And because of the large sensitive area, this detector shows good dominance in fast pulsed and low density radiation detection.

Linyue Liu

2014-01-01

40

The Role of FAST in Pulsar Timing Arrays  

CERN Document Server

The Five-hundred-meter Aperture Spherical Telescope (FAST) will become one of the world-leading telescopes for pulsar timing array (PTA) research. The primary goals for PTAs are to detect (and subsequently study) ultra-low-frequency gravitational waves, to develop a pulsar-based time standard and to improve solar system planetary ephemerides. FAST will have the sensitivity to observe known pulsars with significantly improved signal-to-noise ratios and will discover a large number of currently unknown pulsars. We describe how FAST will contribute to PTA research and show that jitter- and timing-noise will be the limiting noise processes for FAST data sets. Jitter noise will limit the timing precision achievable over data spans of a few years while timing noise will limit the precision achievable over many years.

Hobbs, G; Manchester, R N; Shannon, R M; Kerr, M; Lee, K J; Xu, R

2014-01-01

 
 
 
 
41

Fast neutron response of alanine probes  

International Nuclear Information System (INIS)

The energy response of alanine dosimeter probes with 20% paraffin admixtures for neutron energies between 0.6 and 15 MeV was determined experimentally using accelerator-produced monoenergetic neutrons. Theoretical considerations are made to estimate the energy dependence of the response relative to the response to photons. An optimum mixture of alanine and paraffin is derived which would give an energy-independent neutron tissue dose-response, if the kerma ratio were the only factor influencing the energy response. (author)

1989-01-01

42

Fast Passive Summators for Timing Applications  

CERN Document Server

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

43

A Fast Time-to-Pulse Height Converter  

International Nuclear Information System (INIS)

A fast time-to-pulse height converter representing a development of Green and Bell's gated beam converter is described. The converter is compatible with 2 input pulses in the stop channel and exhibits excellent linearity and time resolution properties. High stability and large output pulses are obtained by using a large time constant in the converting network

1962-01-01

44

Security-constrained expansion planning of fast-response units for wind integration  

International Nuclear Information System (INIS)

This paper proposes a stochastic expansion planning of fast-response thermal units for the large-scale integration of wind generation (WG). The paper assumes that the WG integration level is given and considers the short-term thermal constraints and the volatility of wind units in the planning of fast-response thermal units. The new fast-response units are proposed by market participants. The security-constrained expansion planning approach will be used by an ISO or a regulatory body to secure the optimal planning of the participants' proposed fast-response units with the WG integration. Random outages of generating units and transmission lines as well as hourly load and wind speed forecast errors are modeled in Monte Carlo scenarios. The Monte Carlo simplification methods are introduced to handle large-scale stochastic expansion planning as a tradeoff between the solution accuracy and the calculation time. The effectiveness of the proposed approach is demonstrated through numerical simulations. (author)

2011-01-01

45

Fast timing: Lifetime measurements with LaBr3 scintillators  

International Nuclear Information System (INIS)

In order to perform half-life measurements at Alto, we developed a fast-timing setup using fast scintillators : LaBr3. The main components of our setup and their characteristics (timing properties) are presented. The resulting time resolution, obtained after optimization, and measured off-line with radioactive sources is discussed. This set-up was tested on-line by measuring using the slope method half-lives of 137-139Cs levels fed by the ?- decay of 137-139Xe. The neutron-rich Xe nuclei were produced by 238U photofission using, at low intensity, the electron beam and the line of the future facility ALTO. Our results show the ability of such a fast-timing system to measure half-lives lower than the total time resolution. Off-line and on-line results are discussed.

2010-01-01

46

Analysis of the seismic response of a fast reactor core  

International Nuclear Information System (INIS)

This report deals with the methods to apply for a correct evaluation of the reactor core seismic response. Reference is made to up-to-date design data concerning the PEC core, taking into account the presence of the core-restraint plate located close to the PEC core elements top and applying the optimized iterative procedure between the vessel linear calculation and the non-linear ones limited to the core, which had been described in a previous report. It is demonstrated that the convergence of this procedure is very fast, similar to what obtained in the calculations of the cited report, carried out with preliminary data, and it is shown that the cited methods allow a reliable evaluation of the excitation time histories for the experimental tests in support of the seismic verification of the shutdown system and the core of a fast reactor, as well as relevant data for the experimental, structural and functional, verification of the core elements in the case of seismic loads

1984-01-01

47

Actual preoperative fasting time in Brazilian hospitals: the BIGFAST multicenter study  

Directory of Open Access Journals (Sweden)

Full Text Available José E de Aguilar-Nascimento,1 Ana L de Almeida Dias,2 Diana B Dock-Nascimento,3 Maria Isabel TD Correia,4 Antonio CL Campos,5 Pedro Eder Portari-Filho,6 Sergio S Oliveira71Department of Surgery, Julio Muller University Hospital, Cuiaba, Brazil; 2Federal University of Mato Grosso, Cuiaba, Brazil; 3Department of Sciences and Food, Federal University of Mato Grosso, Cuiaba, Brazil; 4Department of Surgery, Federal University of Minas Gerais, Belo Horizonte, Brazil; 5Department of Surgery, Federal University of Parana, Curitiba, Brazil; 6Department of Surgery, Federal University of Rio de Janeiro State, Rio de Janeiro, Brazil; 7Service of Anesthesiology, Julio Muller University Hospital, Cuiaba, Brazil On behalf of the BIGFAST (Brazilian Group for the Study of Preoperative Fasting Time group Background: Prolonged fasting increases organic response to trauma. This multicenter study investigated the gap between the prescribed and the actual preoperative fasting times in Brazilian hospitals and factors associated with this gap. Methods: Patients (18–90-years-old who underwent elective operations between August 2011 and September 2012 were included in the study. The actual and prescribed times for fasting were collected and correlated with sex, age, surgical disease (malignancies or benign disease, operation type, American Society of Anesthesiologists score, type of hospital (public or private, and nutritional status. Results: A total of 3,715 patients (58.1% females with a median age of 49 (18–94 years from 16 Brazilian hospitals entered the study. The median (range preoperative fasting time was 12 (2–216 hours, and fasting time was longer (P<0.001 in hospitals using a traditional fasting protocol (13 [6–216] hours than in others that had adopted new guidelines (8 [2–48] hours. Almost 80% (n=2,962 of the patients were operated on after 8 or more hours of fasting and 46.2% (n=1,718 after more than 12 hours. Prolonged fasting was not associated with physical score, age, sex, type of surgery, or type of hospital. Patients operated on due to a benign disease had an extended duration of preoperative fasting. Conclusion: Actual preoperative fasting time is significantly longer than prescribed fasting time in Brazilian hospitals. Most of these hospitals still adopt traditional rather than modern fasting guidelines. All patients are at risk of long periods of fasting, especially those in hospitals that follow traditional practices. Keywords: preoperative fasting, preoperative care, multicenter study, intraoperative complications, guideline adherence, perioperative risk

Aguilar-Nascimento JE

2014-02-01

48

Long time response of soft magnetorheological gels.  

Science.gov (United States)

Swollen physical magnetorheological (MR) gels were obtained by self-assembling of triblock copolymers containing dispersed soft magnetic particles. The transient rheological responses of these systems were investigated experimentally. Upon sudden application of a homogeneous magnetic field step change, the storage modulus of MR gels continued to increase with time. Such increase trend of the storage modulus could be expressed by a double-exponential function with two distinct modes, a fast and a slow one. The result was compared with the transient rheological response of equivalent MR fluids (paraffin oil without copolymer) and a MR elastomer (PDMS) and interpreted as the consequence of strong rearrangement of the original particle network under magnetic field. Similar to the structure evolution of MR fluids, the ensemble of results suggests that "chaining" and "clustering" processes are also happening inside the gel and are responsible for the rheological behavior, provided they are happening on a smaller length scale (long chains and clusters are hindered). We show that response times of several minutes are typical for the slow response of MR gels. The characteristic time t(2) for the slow process is significantly dependent on the magnetic flux density, the matrix viscoelastic property, particle volume fraction, and sample's initial particle distribution. In order to validate our results, the role of dynamic strain history was clarified. We show that, in the linear viscoelastic region, the particle rearrangement of MR gels was not hindered or accelerated by the dynamic strain history. PMID:22439870

An, Hai-Ning; Sun, Bin; Picken, Stephen J; Mendes, Eduardo

2012-04-19

49

Fast quantitative characterisation of differential mobility responses.  

Science.gov (United States)

A chromatography-based method for producing mass flux-response surfaces for differential mobility spectrometers is described as a replacement for exponential dilution and mixing approaches. An exponential dilution or mixing experiment typically takes 150 min; while the exponential function in the Gaussian elution profile obtained from linear chromatography may be exploited in approximately 10 s. The approach was demonstrated with a gas chromatograph-mass spectrometer and the correlation of the calibration results to nominal on-column masses was within experimental error for 19 separate analyses. The method was then applied to a gas chromatographic (10.6 eV UV) differential mobility spectrometer. Mass fluxes in the range 10 pg s(-1) to 250 ng s(-1) were generated over the 5 s to 10 s associated with the elution of a chromatographic peak. The characterisations were repeated for a range of electrical field strengths from 10 kV cm(-1) to 30 kV cm(-1). Triplicate runs indicated that the approach was reproducible and that response surfaces could be generated rapidly from chromatographic data. The effects of trace impurities associated with the chromatographic eluent on the relationship between compensation voltage and electrical field strength was observed. This emphasised the importance of managing this aspect of the operation if reliable estimates of alpha functions for the compounds under study were to be obtained. Application of this approach to other detection systems with an 85% reduction in the analytical operations required to produce a reliable calibration function was also noted. PMID:14978520

Veasey, Catherine A; Thomas, C L P

2004-03-01

50

Diving chamber fire response times  

Energy Technology Data Exchange (ETDEWEB)

This study looks at fire risks in diving chambers and the necessary response times to such fires in order to save the occupants of such chambers. A literature search on combustion in hyperbaric or oxygen-enriched environments and on accounts of such incidents was conducted. The likelihood of combustible materials being present in seven hyperbaric chambers was assessed and studied to ascertain appropriate response times. Fire fighting must, it was determined, be fully active within 20 seconds with detection and initiation commencing within 10 seconds. (UK)

NONE

1990-12-31

51

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

International Nuclear Information System (INIS)

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.

2013-02-11

52

Time-resolved fast neutron imaging: simulation of detector performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Using MCNP and GEANT code simulations of neutron and charged-particle transport in the detectors, key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been evaluated.

Vartsky, D.; Mor, I.; Goldberg, M. B.; Mardor, I.; Feldman, G.; Bar, D.; Shor, A.; Dangendorf, V.; Laczko, G.; Breskin, A.; Chechik, R.

2004-01-01

53

Time-resolved fast neutron imaging: simulation of detector performance  

Energy Technology Data Exchange (ETDEWEB)

We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been simulated by means of neutron and charged-particle transport codes.

Vartsky, D. [Soreq NRC, Yavne 81800 (Israel)]. E-mail: david@soreq.gov.il; Mor, I. [Soreq NRC, Yavne 81800 (Israel); Goldberg, M.B. [Soreq NRC, Yavne 81800 (Israel); Mardor, I. [Soreq NRC, Yavne 81800 (Israel); Feldman, G. [Soreq NRC, Yavne 81800 (Israel); Bar, D. [Soreq NRC, Yavne 81800 (Israel); Shor, A. [Soreq NRC, Yavne 81800 (Israel); Dangendorf, V. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Laczko, G. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Breskin, A. [Weizmann Institute of Science, Rehovot (Israel); Chechik, R. [Weizmann Institute of Science, Rehovot (Israel)

2005-04-21

54

Time-resolved fast neutron imaging: simulation of detector performance  

International Nuclear Information System (INIS)

We have analyzed and compared the performance of two novel fast-neutron imaging methods with time-of-flight spectroscopy capability. Key parameters such as detection efficiency, the amount of energy deposited in the converter and the spatial resolution of both detector variants have been simulated by means of neutron and charged-particle transport codes

2005-04-21

55

A new dual threshold time-over-threshold circuit for fast timing in PET  

Science.gov (United States)

Time-over-threshold (ToT) is attractive as a method of combined timing and energy encoding in positron emission tomography (PET) due to its simplicity in implementation and readout. However, conventional single threshold ToT has a nonlinear response and generally suffers from a tradeoff between timing and energy resolution. The resulting poor performance is not fit for applications requiring fast timing, such as time-of-flight (ToF) PET. In this work it is shown experimentally that by replacing single threshold ToT with a dual threshold method in a new compact circuit, excellent time resolution can be achieved (154 ps FWHM for 3 × 3 × 5 mm3 LYSO crystals), suitable for ToF. Dual threshold ToT timing results have been compared to a similar single threshold design, demonstrating that dual threshold ToT performance is far superior to that of single threshold ToT (154 ps versus 418 ps coincidence time resolution for the dual and single threshold cases, respectively). A method of correcting for nonlinearity in dual threshold ToT energy spectra is also demonstrated.

Grant, Alexander M.; Levin, Craig S.

2014-07-01

56

Real time face recognition using adaboost improved fast PCA algorithm  

CERN Multimedia

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

57

NASA AVOSS Fast-Time Wake Prediction Models: User's Guide  

Science.gov (United States)

The National Aeronautics and Space Administration (NASA) is developing and testing fast-time wake transport and decay models to safely enhance the capacity of the National Airspace System (NAS). The fast-time wake models are empirical algorithms used for real-time predictions of wake transport and decay based on aircraft parameters and ambient weather conditions. The aircraft dependent parameters include the initial vortex descent velocity and the vortex pair separation distance. The atmospheric initial conditions include vertical profiles of temperature or potential temperature, eddy dissipation rate, and crosswind. The current distribution includes the latest versions of the APA (3.4) and the TDP (2.1) models. This User's Guide provides detailed information on the model inputs, file formats, and the model output. An example of a model run and a brief description of the Memphis 1995 Wake Vortex Dataset is also provided.

Ahmad, Nash'at N.; VanValkenburg, Randal L.; Pruis, Matthew

2014-01-01

58

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

59

Fast computation of recurrences in long time series  

Science.gov (United States)

The quadratic time complexity of calculating basic RQA measures, doubling the size of the input time series leads to a quadrupling in operations, impairs the fast computation of RQA in many application scenarios. As an example, we analyze the Potsdamer Reihe, an ongoing non-interrupted hourly temperature profile since 1893, consisting of 1,043,112 data points. Using an optimized single-threaded CPU implementation this analysis requires about six hours. Our approach conducts RQA for the Potsdamer Reihe in five minutes. We automatically split a long time series into smaller chunks (Divide) and distribute the computation of RQA measures across multiple GPU devices. To guarantee valid RQA results, we employ carryover buffers that allow sharing information between pairs of chunks (Recombine). We demonstrate the capabilities of our Divide and Recombine approach to process long time series by comparing the runtime of our implementation to existing RQA tools. We support a variety of platforms by employing the computing framework OpenCL. Our current implementation supports the computation of standard RQA measures (recurrence rate, determinism, laminarity, ratio, average diagonal line length, trapping time, longest diagonal line, longest vertical line, divergence, entropy, trend) and also calculates recurrence times. To utilize the potential of our approach for a number of applications, we plan to release our implementation under an Open Source software license. It will be available at http://www.gfz-potsdam.de/fast-rqa/. Since our approach allows to compute RQA measures for a long time series fast, we plan to extend our implementation to support multi-scale RQA.

Rawald, Tobias; Sips, Mike; Marwan, Norbert; Dransch, Doris

2014-05-01

60

A CMOS integrated timing discriminator circuit for fast scintillation counters  

International Nuclear Information System (INIS)

Based on a zero-crossing discriminator using a CR differentiation network for pulse shaping, a new CMOS integrated timing discriminator circuit is proposed for fast (tr ? 2 ns) scintillation counters at the cooler synchrotron COSY-Juelich. By eliminating the input signal's amplitude information by means of an analog continuous-time divider, a normalized pulse shape at the zero-crossing point is gained over a wide dynamic input amplitude range. In combination with an arming comparator and a monostable multivibrator this yields in a highly precise timing discriminator circuit, that is expected to be useful in different time measurement applications. First measurement results of a CMOS integrated logarithmic amplifier, which is part of the analog continuous-time divider, agree well with the corresponding simulations. Moreover, SPICE simulations of the integrated discriminator circuit promise a time walk well below 200 ps (FWHM) over a 40 dB input amplitude dynamic range

1998-06-01

 
 
 
 
61

A CMOS integrated timing discriminator circuit for fast scintillation counters  

Energy Technology Data Exchange (ETDEWEB)

Based on a zero-crossing discriminator using a CR differentiation network for pulse shaping, a new CMOS integrated timing discriminator circuit is proposed for fast (t{sub r} {ge} 2 ns) scintillation counters at the cooler synchrotron COSY-Juelich. By eliminating the input signal`s amplitude information by means of an analog continuous-time divider, a normalized pulse shape at the zero-crossing point is gained over a wide dynamic input amplitude range. In combination with an arming comparator and a monostable multivibrator this yields in a highly precise timing discriminator circuit, that is expected to be useful in different time measurement applications. First measurement results of a CMOS integrated logarithmic amplifier, which is part of the analog continuous-time divider, agree well with the corresponding simulations. Moreover, SPICE simulations of the integrated discriminator circuit promise a time walk well below 200 ps (FWHM) over a 40 dB input amplitude dynamic range.

Jochmann, M.W. [Forschungszentrum Juelich (Germany). Zentrallabor fuer Elektronik

1998-06-01

62

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

CERN Document Server

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

63

Platelet nitrate responsiveness in fasting and postprandial type 2 diabetes.  

Science.gov (United States)

Vascular responsiveness to exogenous nitrates in type 2 diabetes (T2DM) is attenuated in brachial and coronary vessels. We determined platelet responsiveness to nitric oxide (NO) in T2DM and control subjects. We examined whether the postprandial (PP) state affected platelet sensitivity to NO donors in T2DM patients and the extent of correlation between this and measures of oxidative stress, compared to changes in endothelial function. Twelve T2DM subjects were studied fasting and four hours after a test meal and compared with 15 healthy controls. We assessed the inhibitory effects of NO donors on adenosine 5'-diphosphate (ADP)-induced platelet aggregation. Oxidative stress was assessed by lipid-derived free radicals, ex vivo by electron paramagnetic resonance spectroscopy and markers of lipid peroxidation. Endothelial function was assessed by flow-mediated vasodilatation (FMD) of the brachial artery. Results are expressed as (mean +/- SEM). Fasting platelet aggregation was increased in diabetics versus controls (14.86 +/- 1.1 Ohms vs. 10.76 +/- 1.1 Ohms, p < 0.05). Sodium nitroprusside (SNP) and glyceryl trinitrate (GTN) inhibited ADP-induced aggregation by 73.1 +/- 5.9% and 50.3 +/- 7.7% in healthy controls compared to 15.4 +/- 7% and 19.5 +/- 8.2% in T2DM (p < 0.05). Fasting and postprandial inhibition of platelet aggregation with NO donors in T2DM was similar. T2DM patients had higher levels of oxidative stress in the fasting state and postprandially. There were no PP correlations with platelet NO resistance. In conclusion, there is platelet hyporesponsiveness to NO donors (SNP/GTN) in T2DM compared to controls, with increased ADP-induced platelet aggregation. Platelet abnormalities were associated with increased oxidative stress. PMID:16305064

Anderson, Richard A; Ellis, Gethin R; Evans, L Marc; Morris, Keith; Chirkov, Yuri Y; Horowitz, John D; Jackson, Simon K; Rees, Alan; Lewis, Malcolm J; Frenneaux, Michael P

2005-05-01

64

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

65

XTRA: The fast X-ray timing detector on XEUS  

International Nuclear Information System (INIS)

The Rossi X-ray Timing Explorer (RXTE) has demonstrated that the dynamical variation of the X-ray emission from accreting neutron stars and stellar mass black holes is a powerful probe of their strong gravitational fields. At the same time, the X-ray burst oscillations at the neutron star spin frequency have been used to set important constraints on the mass and radius of neutron stars, hence on the equation of state of their high density cores. The X-ray Evolving Universe Spectroscopy mission (XEUS), the potential follow-on mission to XMM-Newton, will have a mirror aperture more than ten times larger than the effective area of the RXTE proportional counter array (PCA). Combined with a small dedicated fast X-ray timing detector in the focal plane (XTRA: XEUS Timing for Relativistic Astrophysics), this collecting area will provide a leap in timing sensitivity by more than one order of magnitude over the PCA for bright sources, and will open a brand new window on faint X-ray sources, owing to the negligible detector background. The use of advanced Silicon drift chambers will further improve the energy resolution by a factor of ? 6 over the PCA, so that spectroscopic diagnostics of the strong field region, such as the relativistically broadened Iron line, will become exploitable. By combining fast X-ray timing and spectroscopy, XTRA will thus provide the first real opportunity to test general relativity in the strong gravity field regime and to constrain with unprecedented accuracy the equation of state of matter at supranuclear density

2004-07-05

66

A fast rise time high voltage pulse burst generator  

International Nuclear Information System (INIS)

A novel type of pulse generator for kicker magnet excitation is described. Series connected thyratrons and coaxial lines are used to produce a burst of four 20 kv, 800 a, fixed length pulses of fast rise and fall time. Inter-pulse spacing is independently adjustable, typically between 200 ns and 20 ?s. The coaxial lines are simultaneously resonantly charged to 40 kv in 1 ms, and the subsequent triggered discharge of each pulse forming network (PFN) initiates the pulse bursts which may be produced at a repetition frequency of 100 hz. This paper presents some of the results obtained with a prototype pulse generator

1983-01-01

67

Time-resolved neutron radiography using a fast pulse reactor  

International Nuclear Information System (INIS)

The feasibility of using a fast pulse reactor as a neutron source in the production of time-resolved neutron radiographs has been demonstrated at the U. S. Army Pulse Radiation Facility. The radiographs were obtained using the transfer radiographic method. Pulses with a full width at half maximum of 50 ?sec and 1.2 x 1017 fissions were utilized to obtain time-resolved radiographs of objects moving at speeds up to 76 m/sec. Investigation of double images, observed in radiographs of test objects moving within this speed range, suggests a method of producing ''motion pictures'' of these objects using one reactor pulse and a suitable stack of detection foils. Resolution of objects moving at speeds greater than 76 m/sec can be obtained by reducing source exposure time to a lower limit of 1 ? sec through employment of electronic gating and image intensification techniques. (11 references) (U.S.)

1975-01-01

68

High stability fast neutron time-of-flight spectrometer  

International Nuclear Information System (INIS)

A fast neutron time-of-flight spectrometer with electronic system of parameter stabilization, in which bench mark signals transmit in the same circuits that the signals of the processes investigated, is described. The time-of-flight spectrometer is developed on the basis of a low-voltage accelerator, tritium target of which serves as a neutron source. As a result a twofold improvement in the instrumental resolution in long-time measurements is achieved, being 1.2 ns. On the flight basis of 7 m the energy width of neutron beam equalling 200 ± 12 keV at the average neutron energy 14.6 MeV has been measured

1986-01-01

69

Observation of Fast Evolution in Parity-Time-Symmetric System  

CERN Document Server

To find and realize the optimal evolution between two states is significant both in theory and application. In quantum mechanics, the minimal evolution is bounded by the gap between the largest and smallest eigenvalue of the Hamiltonian. In the parity-time-symmetric(PT-symmetric) Hamiltonian theory, it was predicted that the optimized evolution time can be reduced drastically comparing to the bound in the Hermitian case, and can become even zero. In this Letter, we report the experimental observation of the fast evolution of a PT-symmetric Hamiltonian in an nuclear magnetic resonance (NMR) quantum system. The experimental results demonstrate that the PT-symmetric Hamiltonian can indeed evolve much faster than that in a quantum system, and time it takes can be arbitrary close to zero.

Zheng, Chao; Long, Gui Lu

2011-01-01

70

Seismic response analysis of the PEC fast reactor building  

International Nuclear Information System (INIS)

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

71

Pediatric fasting times before surgical and radiologic procedures: benchmarking institutional practices against national standards.  

Science.gov (United States)

Prolonged preoperative fasting can be associated with adverse outcomes, particularly in children. Our aims were to assess the time pediatric patients fasted prior to surgical or radiologic procedures and evaluate whether fasting (NPO) orders complied with national guidelines. We measured NPO start time, time of last intake, and time test or surgery was scheduled, took place, or was cancelled in 219 pediatric patients. Findings demonstrate that pediatric patients experienced prolonged fasting before procedures and that the majority of NPO orders were non-compliant with national guidelines. We have developed strategies to reduce fasting times and ensure compliance with recommended national fasting standards. PMID:24365219

Williams, Catherine; Johnson, Pat A; Guzzetta, Cathie E; Guzzetta, Philip C; Cohen, Ira Todd; Sill, Anne M; Vezina, Gilbert; Cain, Sherry; Harris, Christine; Murray, Jodi

2014-01-01

72

Fast-response liquid-crystal lens for 3D displays  

Science.gov (United States)

Three-dimensional (3D) display has become an increasingly important technology trend for information display applications. Dozens of different 3D display solutions have been proposed. The autostereoscopic 3D display based on lenticular microlens array is a promising approach, and fast-switching microlens array enables this system to display both 3D and conventional 2D images. Here we report two different fast-response microlens array designs. The first one is a blue phase liquid crystal lens driven by the Pedot: PSS resistive film electrodes. This BPLC lens exhibits several attractive features, such as polarization insensitivity, fast response time, simple driving scheme, and relatively low driving voltage, as compared to other BPLC lens designs. The second lens design has a double-layered structure. The first layer is a polarization dependent polymer microlens array, and the second layer is a thin twisted-nematic (TN) liquid crystal cell. When the TN cell is switched on/off, the traversing light through the polymeric lens array is either focused or defocused, so that 2D/3D images are displayed correspondingly. This lens design has low driving voltage, fast response time, and simple driving scheme. Simulation and experiment demonstrate that the performance of both switchable lenses meet the requirement of 3D display system design.

Liu, Yifan; Ren, Hongwen; Xu, Su; Li, Yan; Wu, Shin-Tson

2014-02-01

73

Fast time variations of supernova neutrino fluxes and their detectability  

Energy Technology Data Exchange (ETDEWEB)

In the delayed explosion scenario of core-collapse supernovae, the accretion phase shows pronounced convective overturns and a low-multipole hydrodynamic instability, the standing accretion shock instability. 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 {approx}1000 ms{sup -1} 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 standing accretion shock instability 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 megaton-class instruments. We also discuss the information that could be deduced from such a measurement about the physics in the SN core and the explosion mechanism of the SN.

Lunardini, C.; Lund, T., Marek, A., Janka, H.T., Raffelt, G.

2010-09-21

74

Fast time variations of supernova neutrino fluxes and their detectability  

CERN Document Server

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

75

Effect of gadolinium covers on fast dosimeter response  

International Nuclear Information System (INIS)

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 U238 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, U238 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

1993-09-03

76

Fast responsive, optical trace level ammonia sensor for environmental monitoring  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Ammonia is a ubiquitous chemical substance which is created in technical and biological processes and harmful to many different organisms. One specific problem is the toxicity of ammonia in fish at levels of 25 ?g/l - a very common issue in today’s aqua culture. In this study we report a development of a fast responsive, optical ammonia sensor for trace concentrations. Results Different hydrogels have been investigated as host polymers for a pH based sensing mechanism based on fluorescent dyes. A porous hydrophobic fluoropolymer membrane was used as an ion barrier cover layer to achieve a good ammonia permeability. The sensor’s sensitivity towards ammonia as well as crosssensitivity towards pH-value and salinity, and the temperature dependency have been determined. Two different methods to reference fluorescence signals have been employed to eliminate intensity-based measurement drawbacks. Conclusion The presented sensor features high sensitivity and a fast response even at concentrations near 1 ppb. No cross sensitivity towards pH and salinity could be observed and temperature dependency was determined as compensateable. Both referencing approaches prove themselves to be able to provide a simple use of the sensor for in-field applications.

Abel Tobias

2012-10-01

77

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.

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.

2013-01-01

78

XTRA: The fast X-ray timing detector on XEUS  

CERN Document Server

The Rossi X-ray Timing Explorer (RXTE) has demonstrated that the dynamical variation of the X-ray emission from accreting neutron stars and stellar mass black holes is a powerful probe of their strong gravitational fields. At the same time, the X-ray burst oscillations at the neutron star spin frequency have been used to set important constraints on the mass and radius of neutron stars, hence on the equation of state of their high density cores. The X-ray Evolving Universe Spectroscopy mission (XEUS), the potential follow-on mission to XMM-Newton, will have a mirror aperture more than ten times larger than the effective area of the RXTE proportional counter array (PCA). Combined with a small dedicated fast X-ray timing detector in the focal plane (XTRA: XEUS Timing for Relativistic Astrophysics), this collecting area will provide a leap in timing sensitivity by more than one order of magnitude over the PCA for bright sources, and will open a brand new window on faint X-ray sources, owing to the negligible det...

Barret, D

2004-01-01

79

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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....

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

2011-01-01

80

Response time of nuclear plant RTDs  

Energy Technology Data Exchange (ETDEWEB)

Resistance temperature detectors (RTDs) are used for safety-related measurements in nuclear power plants and must therefore respond to temperature changes in a timely fashion. Experience has shown that RTD response time degradation can occur with aging. Therefore, periodic response time testing is performed to ensure that the acceptable response time limits are not exceeded. Periodic tests performed over the last 9 yr have revealed unacceptable response times for a number of RTDs in several nuclear power plants. This paper presents the laboratory and field experience with response time testing of nuclear plant RTDs.

Hashemian, H.M.

1987-01-01

 
 
 
 
81

Response time of nuclear plant RTDs  

International Nuclear Information System (INIS)

Resistance temperature detectors (RTDs) are used for safety-related measurements in nuclear power plants and must therefore respond to temperature changes in a timely fashion. Experience has shown that RTD response time degradation can occur with aging. Therefore, periodic response time testing is performed to ensure that the acceptable response time limits are not exceeded. Periodic tests performed over the last 9 yr have revealed unacceptable response times for a number of RTDs in several nuclear power plants. This paper presents the laboratory and field experience with response time testing of nuclear plant RTDs

1987-06-07

82

Synchronous timing of multi-energy fast beam extraction  

International Nuclear Information System (INIS)

Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering2 combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating RF waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a hole, which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous RF/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the hole in any desired location within the second extraction. The RF/12 signal is used also to synchronize experimenters triggers

1985-05-13

83

Calibration procedure for a fast neutron time-of-flight spectrometer  

International Nuclear Information System (INIS)

The technique for the energy calibration of a fast neutron time-of-flight spectrometer in an interval from 0.4 MeV to 15.5 MeV is described in detail. The calibration is done using 'monoenergetic' neutrons from the T(p,n), T(d,n) and 9Be(d,n) reactions. A response function is deduced which makes it possible to determine the energies of neutron spectra with an accuracy of 1% or better. Such a response function is of great use especially in measurements of continuous neutron spectra, for instance fission neutron spectra. (orig.)

1985-02-15

84

Moderate-fast transient response of the Ge:Ga photoconductors  

Science.gov (United States)

We have fabricated unstressed gallium-doped germanium (Ge:Ga) far-infrared photoconductors for astronomical observations in space. A photoconductor's size as small as 0.5 by 0.5 by 0.5 mm3 is designed to reduce the influence of cosmic high-energy particles. The concentration of Ga in the Ge crystal is 1 X 1014 cm-3. The responsivity of this type of Ge:Ga photoconductor has been improved by decreasing the Ga concentration from 2 X 1014 cm-3 to 1 X 1014 cm-3. Extrinsic semiconductor photoconductors, such as Ge:Ga, which operate at low temperature (less than 4.2 K) and low background photon influx (less than 1 X 108 photons/sec) for space infrared astronomy, have undesirable behavior such as spike noise, hook response, and slow transient response. These phenomena limit the usefulness of the device as a photodetector. The optimum operating temperature of our Ge:Ga photoconductors at which we get the best noise equivalent power (NEP) is 3 K. The response to step increase in influx has a large amplitude with a time constant within 1 sec. This transient response of the photoconductor can be fitted by the model with three time constants. The curve-fitting shows the existence of a component with a time constant of around 0.05 - 0.5 sec, which we define as a moderate-fast transient response. We derived the time constant and the amplitude fraction of the moderate-fast transient response as a function of bias fields at several temperatures. The amplitude ratio of this component to the total response decreases as the bias field increases, and the time constant shortens as the operating temperature rises. Following, we estimated hole life time at the low temperature and under the low background photon influx from hole mobility and responsivity. Moreover, we found good agreement between the time constant of the moderate-fast transient response to the transient time that Hiromoto et al. (1992) pointed from a two-region model of a Ge:Ga photoconductor with ion- planted ohmic contact.

Fujiwara, Mikio; Hiromoto, Norihisa; Araki, Kenichi

1995-09-01

85

Metabolomics of Ramadan fasting: an opportunity for the controlled study of physiological responses to food intake.  

Science.gov (United States)

High-throughput screening techniques that analyze the metabolic endpoints of biological processes can identify the contributions of genetic predisposition and environmental factors to the development of common diseases. Studies applying controlled physiological challenges can reveal dysregulation in metabolic responses that may be predictive for or associated with these diseases. However, large-scale epidemiological studies with well controlled physiological challenge conditions, such as extended fasting periods and defined food intake, pose logistic challenges. Culturally and religiously motivated behavioral patterns of life style changes provide a natural setting that can be used to enroll a large number of study volunteers. Here we report a proof of principle study conducted within a Muslim community, showing that a metabolomics study during the Holy Month of Ramadan can provide a unique opportunity to explore the pre-prandial and postprandial response of human metabolism to nutritional challenges. Up to five blood samples were obtained from eleven healthy male volunteers, taken directly before and two hours after consumption of a controlled meal in the evening on days 7 and 26 of Ramadan, and after an over-night fast several weeks after Ramadan. The observed increases in glucose, insulin and lactate levels at the postprandial time point confirm the expected physiological response to food intake. Targeted metabolomics further revealed significant and physiologically plausible responses to food intake by an increase in bile acid and amino acid levels and a decrease in long-chain acyl-carnitine and polyamine levels. A decrease in the concentrations of a number of phospholipids between samples taken on days 7 and 26 of Ramadan shows that the long-term response to extended fasting may differ from the response to short-term fasting. The present study design is scalable to larger populations and may be extended to the study of the metabolic response in defined patient groups such as individuals with type 2 diabetes. PMID:24906381

Mathew, Sweety; Krug, Susanne; Skurk, Thomas; Halama, Anna; Stank, Antonia; Artati, Anna; Prehn, Cornelia; Malek, Joel A; Kastenmüller, Gabi; Römisch-Margl, Werner; Adamski, Jerzy; Hauner, Hans; Suhre, Karsten

2014-01-01

86

Fast, Linear Time Hierarchical Clustering using the Baire Metric  

CERN Document Server

The Baire metric induces an ultrametric on a dataset and is of linear computational complexity, contrasted with the standard quadratic time agglomerative hierarchical clustering algorithm. In this work we evaluate empirically this new approach to hierarchical clustering. We compare hierarchical clustering based on the Baire metric with (i) agglomerative hierarchical clustering, in terms of algorithm properties; (ii) generalized ultrametrics, in terms of definition; and (iii) fast clustering through k-means partititioning, in terms of quality of results. For the latter, we carry out an in depth astronomical study. We apply the Baire distance to spectrometric and photometric redshifts from the Sloan Digital Sky Survey using, in this work, about half a million astronomical objects. We want to know how well the (more costly to determine) spectrometric redshifts can predict the (more easily obtained) photometric redshifts, i.e. we seek to regress the spectrometric on the photometric redshifts, and we use clusterwi...

Contreras, Pedro

2011-01-01

87

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

2008-01-01

88

Fast minute magnetic field coil for time-resolved nanospintronics  

CERN Document Server

Nanospintronic and related research often requires the application of fast rising magnetic field pulses in the plane of the studied planar structure. We have designed and fabricated sub-milimeter-sized coils capable of delivering pulses of the magnetic field up to ~ 500 Oe in the plane of the sample with the rise time of order of 10 ns. The placement of the sample above the coil allows for an easy access to its surface with manipulators or light beams for, e.g., Kerr microscopy. We use the fabricated coil to drive magnetic domain walls in 1 ${\\mu}$ m wide permalloy wires and measure magnetic domain wall velocity as a function of the applied magnetic field.

Pawliszak, ?ukasz; Zgirski, Maciej

2014-01-01

89

A fast response wide range solid state densitometer  

International Nuclear Information System (INIS)

Routine assessment of radiation doses for about 18,000 persons per month is still being carried out by the Radiation Protection Services Division through its Film Badge Service, in addition to 21,000 per month through TLD. This necessitated, earlier, the development of a semiautomatic Film Densitometer Reader which uses a densitometer having an expensive photomultiplier with associated high voltage supply and elaborate electronic circuitry covering a linear range of 0-4 optical density. This paper describes a linear densitometer developed using an ultrasensitive fast response silicon photodiode (which forms part of a solid state photo detector - amplifier combination) and a temperature compensated log ratio amplifier. The instrument is simple cost-effective and reliable. It measures diffuse optical density of the monitor film in the range of 0 to 5 with a least measurable density of 0.01. (author). 6 refs., 2 figs

1993-01-01

90

Seismic response analysis of the PEC fast reactor building  

International Nuclear Information System (INIS)

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)

1987-05-04

91

Fast cognitive decline at the time of dementia diagnosis: a major prognostic factor for survival in the community.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

BACKGROUND/AIMS: Current findings suggest the existence of a category of fast cognitive decliners with a poorer prognosis but better treatment response. Our study aimed at confirming the concept of fast decliners at the time of Alzheimer's disease (AD) diagnosis which best predicts mortality, in an unselected sample. METHODS: 245 incident cases of AD were selected from the French longitudinal cohort PAQUID. We investigated a different threshold of cognitive decline [measured by the annual los...

2007-01-01

92

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

93

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

2007-02-01

94

Time response of microencapsulated liquid crystals. 1. Steady state characteristics  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work is to investigate steady state characteristics as a first step to develop fast quantitative thermometer using thermochromic liquid crystals, especially to evaluate inherent response time. Spectral characteristics are measured by means of a spectrometer, and their optical properties are evaluated by CIE 1931 standard colorimetric system, XYZ. Wavelength of maximum intensity and hue value show good correlation between temperature. (author).

Akino, Norio; Kubo, Shinji (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment); Morimoto, S.; Ichimiya, K.; Sagiya, S.; Nakanishi, M.

1994-05-01

95

Response surface methodology to optimize novel fast disintegrating tablets using ? cyclodextrin as diluent.  

Science.gov (United States)

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, X (1)), superdisintegrant (Croscarmellose sodium, X (2)), and direct compression aid (Spray dried lactose, X (3)). Tablets were prepared by direct compression method on B2 rotary tablet press using flat plain-face punches and characterized for weight variation, thickness, disintegration time (Y (1)), and hardness (Y (2)). Disintegration time was strongly affected by quadratic terms of ? cyclodextrin, croscarmellose sodium, and spray-dried lactose. The positive value of regression coefficient for ? cyclodextrin suggested that hardness increased with increased amount of ? cyclodextrin. In general, disintegration of tablets has been reported to slow down with increase in hardness. However in the present study, higher concentration of ? cyclodextrin was found to improve tablet hardness without increasing the disintegration time. Thus, ? cyclodextrin is proposed as a suitable diluent to achieve fast disintegrating tablets with sufficient hardness. Good correlation between the predicted values and experimental data of the optimized formulation validated prognostic ability of response surface methodology in optimizing fast disintegrating tablets using ? cyclodextrin as a diluent. PMID:21086083

Late, Sameer G; Banga, Ajay K

2010-12-01

96

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

97

Response of a single-crystal diamond detector to fast neutrons  

International Nuclear Information System (INIS)

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 nTOF 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

2013-10-01

98

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

99

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.

2003-05-12

100

Fast stability analysis of power oscillations by frequency response method  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the examination result of high speed frequency response testing method used for analysis of a large scale power system. For enhancement of the computation speed of each frequency response, it was proposed that a transfer matrix is expressed by three matrixes, and is determined by utilizing the sparsity of the matrixes. Furthermore, for reduction of the number of frequencies to be used for the frequency response, it was proposed that the chopped frequency interval is not fixed on a constant value, but is varied, depending on the variation speed of the response. The above method was applied to a model power system comprising 107 model electric generators. As a result, the computation time for the frequency response required by the former supposed method was about one-22nd of that by a conventional method. Also, the computation amount required by the latter supposed method was about one-sixth of that by the conventional method. The overall computation time by this proposed method was about 9 seconds, that is about one-137th based on about 21 minutes by the conventional method. This reveals the usefulness of this method. (8 figs, 2 tabs, 16 refs)

Kakimoto, Naoto; Hayashi, Muneaki; Onogi, Yukio

1987-11-20

 
 
 
 
101

Fast simulated annealing algorithm for BAEP time delay estimation using a reduced order dynamic model.  

Science.gov (United States)

The extraction of Brainstem Auditory Evoked Potentials (BAEPs), from the EEG background, is of high clinical interest. The present paper can be considered as a continuation of our previous work related to the BAEP estimation in endocochlear pathologies. In our previous published work, we proposed a technique for time delay estimation on the basis of the BAEPs in response to successive stimulations. Put in a different manner, our objective was the estimation of the dynamics of the cochlea that is responsible for the delayed responses. The estimation technique was based on optimization of a non-linear criterion by means of Simulated Annealing Time Delay Estimation (SATDE) algorithm. However, it is well known that such heuristic algorithms are time consuming and largely depend on the number of parameters to be estimated. The present paper demonstrates that modeling the non-stationarity of responses considerably decreases the convergence time to the global minimum. The newly proposed method in this paper, called Fast Simulated Annealing Time Delay Estimation (FSATDE) algorithm, has been validated on both simulated and real signals. PMID:16139768

Cherrid, Nada; Naït-Ali, Amine; Siarry, Patrick

2005-10-01

102

Mathematical modeling of the LCD response time  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Techniques to reduce LCD motion blur are extensively used in industry and they depend on an inherent LCD parameter: response time. However, normative response time is not a sufficient reference to improve LCD performance and all the gray-to-gray response-time quantities are required to obtain good improvement. However, measuring and gathering all the gray-to-gray transitions takes an excessive amount of time. Consequently, we propose a novel LCD model to simulate as well as compute gray-to-gr...

Adam, Pierre; Bertolino, Pascal; Lebowsky, Fritz

2007-01-01

103

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

2009-06-01

104

A LaBr3: Ce fast-timing array for DESPEC at FAIR  

Science.gov (United States)

The design of a fast-timing ?-ray detection array aimed at measuring sub-nanosecond half-lives using LaBr3:Ce scintillation crystals is presented. This array will complement novel and existing charged particle and neutron detector arrays at the low-energy branch of a fragment separator (Super-FRS) to be built within the NuSTAR collaboration as part of the future Facility for Anti-proton and Ion Research (FAIR). The array will be used in conjunction with the Advanced Implantation Detector Array (AIDA), to measure implant-decay correlations. Monte-Carlo simulations have been performed to determine the design of the proposed fast-timing array around a localised implantation point. In particular, simulations were used to determine the full-energy peak efficiencies for single cylindrical, conical and 'hybrid' detector geometries, as well as complete array configurations of 'hybrid' and ?1.5 in.×2 in. cylindrical crystals. Timing precision calculations were then used to determine the timing response for each configuration based on its simulated efficiency. An informed decision based on the simulated efficiencies and timing precision calculations allowed the optimum configuration for the array to be determined.

Roberts, Oliver J.; Bruce, Alison M.; Regan, Patrick H.; Podolyák, Zsolt; Townsley, Christopher M.; Smith, John F.; Mulholland, Kieran F.; Smith, Andrew

2014-06-01

105

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

106

Ultraviolet fast-response photoelectric effects in LiTaO3 single crystal  

International Nuclear Information System (INIS)

The photoelectric effects of LiTaO3 (LTO) single crystals are experimentally studied with two kinds of LTO wafers, 100 tilted and untilted, at room temperature. A transient open-circuit photoelectrical response of 143 ps rise time is observed in the 100 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 ?m finger width and 10 ?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.

2010-01-13

107

CVD diamond based soft X-ray detector with fast response  

International Nuclear Information System (INIS)

A soft X-ray detector has been made with high quality chemical vapor deposited (CVD) diamond and the electrical structure of micro-strip. Through the measurement of response time on a laser with the pulse width of 10 ps, the full width at half maximum of the data got in the oscilloscope was 115 ps. The rise time of the CVD diamond detector was calculated to be 49 ps. In the experiment on the laser prototype facility, the signal got by the CVD diamond detector was compared with that got by a soft X-ray spectrometer. Both signals coincided well. The detector is proved to be a kind of reliable soft X-ray detector with fast response and high signal-to-noise ratio. (authors)

2010-06-01

108

A sex difference in the response to fasting.  

Science.gov (United States)

We determined whether women and men would alter their pattern of food intake after they had deprived themselves of food. We found that women consumed 12% less food after fasting and that men ate 28% more food after fasting. Serving more food on the test day did not increase food intake of women. Women, who ate at a nearly constant rate (linear eaters), consumed less food than those eating at an initially high speed which decreased over the course of the meal (decelerated eaters). Women decreased their food intake after fasting as their eating pattern became more linear. After fasting, men increased their food intake, and the rate at which they ate became more decelerated. Food intake of both women and men was normalized after fasting by providing feedback that encouraged them to eat according to the pattern they showed in the non-fasted condition. The results support the hypothesis that linear eating, and the dieting that elicits linear eating, are risk factors for the development of the abnormal linear eating pattern that characterizes patients with anorexia nervosa. The data also provide additional support for the use of behavioral feedback to normalize the pattern of eating for individuals who have difficulty maintaining their body weight. PMID:21514312

Zandian, Modjtaba; Ioakimidis, Ioannis; Bergh, Cecilia; Leon, Michael; Södersten, Per

2011-07-01

109

Response Time Optimization of a Reactor's Monitoring and Alarm System  

International Nuclear Information System (INIS)

The reactor's monitoring system under development [1], measures neutron flux density using Boron lined ionization chambers. The current signal from the ionization chambers is amplified and digitized, and a digital processor calculates the momentary flux and its doubling time. An alarm signal is further generated whenever the flux is too high or grows too rapidly. The alarm signal is sent to the reactor's automatic emergency shut down circuit. Unfortunately, fluctuations and noise in the sampled signal have a significant influence on the calculated doubling time and may generate false alarms. Low-pass filtering of the signal will slow down the response time. An optimal filter should balance the conflicting requirements for fast response and for low rate false alarms

2002-05-22

110

Sensor response time monitoring using noise analysis  

International Nuclear Information System (INIS)

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

111

Sensor response time monitoring using noise analysis  

Energy Technology Data Exchange (ETDEWEB)

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.

Hashemian, H.M.; Thie, J.A.; Upadhyaya, B.R.; Holbert, K.E.

1988-01-01

112

Fast Clustering for Time-series Data with Average-time-sequence-vector Generation Based on Dynamic Time Warping  

Science.gov (United States)

This paper proposes a fast clustering method for time-series data based on average time sequence vector. A clustering procedure based on an exhaustive search method is time-consuming although its result typically exhibits high quality. BIRCH, which reduces the number of examples by data squashing based on a data structure CF (Clustering Feature) tree, represents an effective solution for such a method when the data set consists of numerical attributes only. For time-series data, however, a straightforward application of BIRCH based on a Euclidean distance for a pair of sequences, miserably fails since such a distance typically differs from human's perception. A dissimilarity measure based on DTW (Dynamic Time Warping) is desirable, but to the best of our knowledge no methods have been proposed for time-series data in the context of data squashing. In order to circumvent this problem, we propose DTWS (Dynamic Time Warping Squashed) tree, which employs a dissimilarity measure based on DTW, and compresses time sequences to the average time sequence vector. An average time sequence vector is obtained by a novel procedure which estimates correct shrinkage of a result of DTW. Experiments using the Australian sign language data demonstrate the superiority of the proposed method in terms of correctness of clustering, while its degradation of time efficiency is negligible.

Nakamoto, Kazuki; Yamada, Yuu; Suzuki, Einoshin

113

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

114

Real time computers for safety critical and safety related systems of prototype Fast Breeder Reactor  

International Nuclear Information System (INIS)

Prototype Fast Breeder Reactor (PFBR), the 500 MWe fast reactor under construction at Kalpakkam extensively uses Real time Computers (RTC) in the Instrumentation and Control systems. The computer systems are designed as per the safety guides of AERB and other international standards. The hardware and software architecture of the computers are explained in this paper. (author)

2005-02-01

115

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

116

Fast versus slow response in climate change: implications for the global hydrological cycle  

Energy Technology Data Exchange (ETDEWEB)

Recent studies have shown that changes in global mean precipitation are larger for solar forcing than for CO{sub 2} forcing of similar magnitude. In this paper, we use an atmospheric general circulation model to show that the differences originate from differing fast responses of the climate system. We estimate the adjusted radiative forcing and fast response using Hansen's ''fixed-SST forcing'' method. Total climate system response is calculated using mixed layer simulations using the same model. Our analysis shows that the fast response is almost 40% of the total response for few key variables like precipitation and evaporation. We further demonstrate that the hydrologic sensitivity, defined as the change in global mean precipitation per unit warming, is the same for the two forcings when the fast responses are excluded from the definition of hydrologic sensitivity, suggesting that the slow response (feedback) of the hydrological cycle is independent of the forcing mechanism. Based on our results, we recommend that the fast and slow response be compared separately in multi-model intercomparisons to discover and understand robust responses in hydrologic cycle. The significance of this study to geoengineering is discussed. (orig.)

Bala, Govindasamy [Indian Institute of Science, Divecha Center for Climate Change and Center for Atmospheric and Oceanic Sciences, Bangalore (India); Caldeira, K. [Carnegie Institution, Department of Global Ecology, Stanford, CA (United States); Nemani, R. [NASA Ames Research Center, Santa Clara, CA (United States)

2010-08-15

117

Fast Human Brain Magnetic Resonance Responses Associated With Epileptiform Spikes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Neuronal currents produce local electromagnetic fields that can potentially modulate the phase of the magnetic resonance signal and thus provide a contrast mechanism tightly linked to neuronal activity. Previous work has demonstrated the feasibility of direct MRI of neuronal activity in phantoms and cell culture, but in vivo efforts have yielded inconclusive, conflicting results. The likelihood of detecting and validating such signals can be increased with (i) fast gradient-echo echo-planar i...

Sundaram, Padmavathi; Wells, William M.; Mulkern, Robert V.; Bubrick, Ellen J.; Bromfield, Edward B.; Mu?nch, Mirjam; Orbach, Darren B.

2010-01-01

118

A note on fast times of Brownian motion with variable drift  

CERN Document Server

A famous result of Orey and Taylor gives the Hausdorff dimension of the set of fast times, that is the set of points where linear Brownian motion moves faster than according to the law of iterated logarithm. In this paper we examine what happens to the set of fast times if a variable drift is added to linear Brownian motion. In particular, we will show that the Hausdorff dimension of the set of fast times cannot be decreased by adding a function to Brownian motion.

Ruscher, Julia

2012-01-01

119

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

International Nuclear Information System (INIS)

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

1989-08-14

120

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<0.0001). Of 344 IFG individuals, who were subjected to standard OGTT, 182(53%) had Normal Glucose Tolerance (NGT), 127(37%) were Impaired Glucose Tolerance (IGT) and 35(10%) were diabetics. The difference in frequency of the three groups was statistically significant (p<0.0001). A significantly large number of asymptomatic adults are suffering from IFG in our set up. When IFG individuals are subjected to 75-g OGTT, their 2-h PG results showed about one third have IGT and also a significant number of IFG individuals are found to be patients of diabetes. (author)

2006-01-01

 
 
 
 
121

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

122

Time Domain Response of the ARIANNA Detector  

CERN Document Server

The Antarctic Ross Ice Shelf Antenna Neutrino Array (ARIANNA) is a high-energy neutrino detector designed to record the Askaryan electric field signature of cosmogenic neutrino interactions in ice. To understand the inherent radio-frequency (RF) neutrino signature, the time-domain response of the ARIANNA RF receiver must be measured. ARIANNA uses Create CLP5130-2N log-periodic dipole arrays (LPDAs). The associated effective height operator converts incident electric fields to voltage waveforms at the LDPA terminals. The effective height versus time and incident angle was measured, along with the associated response of the ARIANNA RF amplifier. The results are verified by correlating to field measurements in air and ice, using oscilloscopes. Finally, theoretical models for the Askaryan electric field are combined with the detector response to predict the neutrino signature.

Barwick, S W; Besson, D Z; Hanson, J C; Klein, S R; Kleinfelder, S A; Piasecki, M; Ratzlaff, K; Reed, C; Roumi, M; Stezelberger, T; Tatar, J; Walker, J; Young, R; Zou, L

2014-01-01

123

Investigation of response time testing requirements  

Energy Technology Data Exchange (ETDEWEB)

The purpose of the Response Time Testing (RTT) Program was to determine if requirements for RTT could be eliminated for specific pressure and differential pressure transmitters and switches. This program was initiated when experience and historical data from a significant number of nuclear power plants indicated that, while RTT is both resource and exposure intensive, an insignificant number of pressure sensor failures have been detected through this type of testing. Assessment of plant response time data and performance of Failure Modes and Effects Analysis (FMEA) on sensor hardware were the mechanisms used by the program to determine the redundancy of RTT in conjunction with other required periodic testing (e.g., calibrations, channel checks, surveillance tests). In general, the FMEA results indicated RTT is redundant to other periodic tests. Results of the program identified only two response time failure modes and two manufacturing/handling defects that may not concurrently affect sensor output. The two failure modes affect a limited number of sensor models. Appropriate testing has been identified in cases where response time degradation may not be coincident with significant sensor output change. 14 refs., 19 figs., 39 tabs.

Swisher, V.I. (Performance Associates, Inc., Niantic, CT (USA)); Mayo, C.W. (Science Applications International Corp., Lynchburg, VA (USA)); Weiss, J. (Electric Power Research Inst., Palo Alto, CA (USA))

1991-05-01

124

Time resolved LIF with a fast-scanning diode laser  

International Nuclear Information System (INIS)

Ion phase-space resolved fluctuations carry detailed information pertaining to transport as well as to the plasma degrees of freedom. Using a 500 mW diode laser that can scan over Doppler broadened Argon ion lines in less than 50 microseconds we observe fluctuations and correlations with an adjustable bandwidth by means of a comb-filter. The high laser intensity coupled with fast scanning makes optical pumping between the Zeeman sublevels observable. This opens a new strategy for optical tagging as well as observing correlations between fluctuations at different ion velocities. The experiments are performed in a 2 meter length 0.1 meter diameter CW Argon gas discharge created by a 10 MHz inductive plasma source in a uniform 1 kG magnetic field. The plasma density is typically 109 cm-3, the electron temperature is 2 eV and the ions have a temperature of 0.1 eV. Under these conditions the ions are weakly collisional.

2010-05-01

125

Time-resolved fast-neutron imaging with a pulse-counting image intensifier  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new imaging method that combines high-efficiency fast-neutron detection with sub-ns time resolution is presented. This is achieved by exploiting the high neutron detection efficiency of a thick scintillator and the fast timing capability and flexibility of light-pulse detection with a dedicated image intensifier. The neutron converter is a plastic scintillator slab or, alternatively, a scintillating fibre screen. The scintillator is optically coupled to a pulse counting image intensifier wh...

Dangendorf, Volker

2007-01-01

126

Fast and Flexible Multivariate Time Series Subsequence Search.  

Science.gov (United States)

Multivariate Time-Series (MTS) are ubiquitous, and are generated in areas as disparate as sensor recordings in aerospace systems, music and video streams, medical monitoring, and financial systems. Domain experts are often interested in searching for inte...

A. N. Srivastava K. Bhaduri N. C. Oza Q. Zhu

2010-01-01

127

Time-of-flight measurement of fast neutrons with Timepix detectors  

Science.gov (United States)

Timepix pixel detectors have been used to study the response of silicon hybrid pixel detectors to fast neutrons from a pulsed neutron beam at WNR FP30R, a 14 m long flight path, in the Los Alamos Neutron Science Center. Neutrons with kinetic energies up to 600 MeV were available. In order to enhance the conversion of neutrons to energetic charged particles, several converter foils and filters were attached to the 300 ?m thick silicon sensor, i.e. polyethylene, polyethylene with aluminum, 6LiF, 6LiF with aluminum, aluminum. The Time-of-Arrival mode of the Timepix detectors has permitted the application of the Time-of-Flight (TOF) technique for the assignment of the detected interactions in the form of clusters (groups of adjacent pixels) in the pixel matrix, to the kinetic energies of the incident neutrons. It was found that, for lower neutron energies ( ~ MeV range) the cluster rates below the polyethylene and the polyethylene and aluminum region, produced by recoil protons, are a good measure for the mean kinetic energies of neutrons. For energies above 50 MeV nuclear reactions in the silicon dominate the detector response. In this energy range the shape of the clusters indicates the neutron kinetic energy.

Bergmann, B.; Nelson, R. O.; O'Donnell, J. M.; Pospisil, S.; Solc, J.; Takai, H.; Vykydal, Z.

2014-05-01

128

XTRA: The fast X-ray timing detector on XEUS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Rossi X-ray Timing Explorer (RXTE) has demonstrated that the dynamical variation of the X-ray emission from accreting neutron stars and stellar mass black holes is a powerful probe of their strong gravitational fields. At the same time, the X-ray burst oscillations at the neutron star spin frequency have been used to set important constraints on the mass and radius of neutron stars, hence on the equation of state of their high density cores. The X-ray Evolving Universe S...

Barret, Didier

2004-01-01

129

Parallel Configuration For Fast Superconducting Strip Line Detectors With Very Large Area In Time Of Flight Mass Spectrometry  

International Nuclear Information System (INIS)

We realized a very fast and large Superconducting Strip Line Detector based on a parallel configuration of nanowires. The detector with size 200x200 ?m2 recorded a sub-nanosecond pulse width of 700 ps in FWHM (400 ps rise time and 530 ps relaxation time) for lysozyme monomers/multimers molecules accelerated at 175 keV in a Time of Flight Mass Spectrometer. This record is the best in the class of superconducting detectors and comparable with the fastest NbN superconducting single photon detector of 10x10 ?m2. We succeeded in acquiring mass spectra as the first step for a scale-up to ?mm pixel size for high throughput MS analysis, while keeping a fast response.

2009-12-16

130

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

131

Fast and Flexible Multivariate Time Series Subsequence Search  

Science.gov (United States)

Multivariate Time-Series (MTS) are ubiquitous, and are generated in areas as disparate as sensor recordings in aerospace systems, music and video streams, medical monitoring, and financial systems. Domain experts are often interested in searching for interesting multivariate patterns from these MTS databases which often contain several gigabytes of data. Surprisingly, research on MTS search is very limited. Most of the existing work only supports queries with the same length of data, or queries on a fixed set of variables. In this paper, we propose an efficient and flexible subsequence search framework for massive MTS databases, that, for the first time, enables querying on any subset of variables with arbitrary time delays between them. We propose two algorithms to solve this problem (1) a List Based Search (LBS) algorithm which uses sorted lists for indexing, and (2) a R*-tree Based Search (RBS) which uses Minimum Bounding Rectangles (MBR) to organize the subsequences. Both algorithms guarantee that all matching patterns within the specified thresholds will be returned (no false dismissals). The very few false alarms can be removed by a post-processing step. Since our framework is also capable of Univariate Time-Series (UTS) subsequence search, we first demonstrate the efficiency of our algorithms on several UTS datasets previously used in the literature. We follow this up with experiments using two large MTS databases from the aviation domain, each containing several millions of observations. Both these tests show that our algorithms have very high prune rates (>99%) thus needing actual disk access for only less than 1% of the observations. To the best of our knowledge, MTS subsequence search has never been attempted on datasets of the size we have used in this paper.

Bhaduri, Kanishka; Oza, Nikunj C.; Zhu, Qiang; Srivastava, Ashok N.

2010-01-01

132

Continuous data recording on fast real-time systems  

International Nuclear Information System (INIS)

The PCU-Project launched for the enhancement of the vertical stabilisation system at JET required the design of a new real-time control system with the challenging specifications of 2Gops and a cycle time of 50 ?s. The RTAI based architecture running on an x86 multi-core processor technology demonstrated to be the best platform for meeting the high requirements. Moreover, on this architecture thanks to the smart allocation of the interrupts it was possible to demonstrate simultaneous data streaming at 50 MBs on Ethernet while handling a real-time 100 kHz interrupt source with a maximum jitter of just 3 ?s. Because of the memory limitation imposed by 32 bit version Linux running in kernel mode, the RTAI-based new controller allows a maximum practical data storage of 800 MB per pulse. While this amount of data can be accepted for JET normal operation it posed some limitations in the debugging and commissioning of the system. In order to increase the capability of the data acquisition of the system we have designed a mechanism that allows continuous full bandwidth (56 MB/s) data streaming from the real-time task (running in kernel mode) to either a data collector (running in user mode) or an external data acquisition server. The exploited architecture involves a peer to peer mechanisms where the sender running in RTAI kernel mode broadcasts large chunks of data using UDP packets, implemented using the 'fcomm' RTAI extension , to a receiver that will store the data. The paper will present the results of the initial RTAI operating system tests, the design of the streaming architecture and the first experimental results.

2010-07-01

133

Renal responses to plasma volume expansion and hyperosmolality in fasting seal pups  

Science.gov (United States)

Renal responses were quantified in northern elephant seal (Mirounga angustirostris) pups during their postweaning fast to examine their excretory capabilities. Pups were infused with either isotonic (0.9%; n = 8; Iso) or hypertonic (16.7%; n = 7; Hyper) saline via an indwelling catheter such that each pup received 3 mmol NaCl/kg. Diuresis after the infusions was similar in magnitude between the two treatments. Osmotic clearance increased by 37% in Iso and 252% in Hyper. Free water clearance was reduced 3.4-fold in Hyper but was not significantly altered in Iso. Glomerular filtration rate increased 71% in the 24-h period after Hyper, but no net change occurred during the same time after Iso. Natriuresis increased 3.6-fold in Iso and 5.3-fold in Hyper. Iso decreased plasma arginine vasopressin (AVP) and cortisol acutely, whereas Hyper increased plasma and excreted AVP and cortisol. Iso was accompanied by the retention of water and electrolytes, whereas the Hyper load was excreted within 24 h. Natriuresis is attributed to increased filtration and is independent of an increase in atrial natriuretic peptide and decreases in ANG II and aldosterone. Fasting pups appear to have well-developed kidneys capable of both extreme conservation and excretion of Na(+).

Ortiz, Rudy M.; Wade, Charles E.; Costa, Daniel P.; Ortiz, C. Leo

2002-01-01

134

A Preliminary Study of Fast Time-Resolved Luminescence in Al2O3:C  

International Nuclear Information System (INIS)

Fast time-resolved optically stimulated luminescence has been observed in alpha-Al2O3:C single crystals under near-IR stimulation. The time-resolved measurements were performed with a spectrometer system comprising a Quanta-Ray MOPO 710 laser as stimulation source and a detection system including a fast photomultiplier detector coupled to a multi-scalar with a minimum dwell time of 5 ns. Results of multi-exponential lifetime analysis of the time-resolved data are reported and comparisons made with other relevant data produced by slower pulsed optically stimulated luminescence and pulsed radioluminescence measurements. (author)

1998-07-05

135

The generalized centroid difference method for picosecond sensitive determination of lifetimes of nuclear excited states using large fast-timing arrays  

Energy Technology Data Exchange (ETDEWEB)

A novel method for direct electronic “fast-timing” lifetime measurements of nuclear excited states via ?–? coincidences using an array equipped with N?N equally shaped very fast high-resolution LaBr{sub 3}(Ce) scintillator detectors is presented. Analogous to the mirror symmetric centroid difference method, the generalized centroid difference method provides two independent “start” and “stop” time spectra obtained by a superposition of the N(N?1)?–? time difference spectra of the N detector fast-timing system. The two fast-timing array time spectra correspond to a forward and reverse gating of a specific ?–? cascade. Provided that the energy response and the electronic time pick-off of the detectors are almost equal, a mean prompt response difference between start and stop events is calibrated and used as a single correction for lifetime determination. These combined fast-timing arrays mean ?–? time-walk characteristics can be determined for 40keVfast-timing array delivered an absolute time resolving power of 3 ps for 10 000 ?–? events per total fast timing array start and stop time spectrum. The new method is tested over the total dynamic range by the measurements of known picosecond lifetimes in standard ?-ray sources.

Régis, J.-M., E-mail: regis@ikp.uni-koeln.de [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Mach, H. [Departamento de Física Atómica y Nuclear, Universidad Complutense, 28040 Madrid (Spain); Simpson, G.S. [Laboratoire de Physique Subatomique et de Cosmologie Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Jolie, J.; Pascovici, G.; Saed-Samii, N.; Warr, N. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Bruce, A. [School of Computing, Engineering and Mathematics, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Degenkolb, J. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Fraile, L.M. [Departamento de Física Atómica y Nuclear, Universidad Complutense, 28040 Madrid (Spain); Fransen, C. [Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany); Ghita, D.G. [Horia Hulubei National Institute for Physics and Nuclear Engineering, 77125 Bucharest (Romania); and others

2013-10-21

136

Time to positivity of neonatal blood cultures: fast and furious?  

Science.gov (United States)

The aim of this study was to determine the time to positivity (TTP) of neonatal blood cultures, to investigate differences between early onset versus late-onset sepsis, and non-proven versus proven sepsis, and to examine differences in TTP by organism type using a retrospective observational study at the Neonatal Intensive Care Unit, Antwerp University Hospital, Belgium. The subjects were 1828 neonates with suspected sepsis who were treated with antimicrobials for at least 3 days. The TTP was recorded for all episodes of suspected sepsis in an approximately 6.5 year period. A total of 2916 blood cultures were collected, of which 437 (15%) became positive. The overall TTP was 21.33 h (Q1-Q3 13.17-32.46). The difference between the median TTP in early onset versus late-onset sepsis was 0.83 h (22.00 versus 21.17 h, P=0.75). The median TTP for Gram-negative organisms was 11.17 h (Q1-Q3 8.84-15.67), whereas the median TTP for Gram-positive organisms was 23.59 h (Q1-Q3 15.29-34.58, P<0.001). In Gram-positive isolates, the median TTP for coagulase-negative staphylococci (CNS) was 26.67 h (Q1-Q3 19.00-38.17), whereas the median TTP for non-CNS was 12.83 h (Q1-Q3 10.50-18.17, P<0.001). The median TTP in proven sepsis was 20.17 h (Q1-Q3 13.00-30.37), whereas it was 29.67 h (Q1-Q3 21.17-50.63, P<0.001) in non-proven sepsis. TTP of neonatal blood cultures was significantly shorter for Gram-negative organisms. We suggest shortening the total incubation time of neonatal blood cultures to a maximum of 3 days. However, blood cultures collected in infants<72 h of age might require a longer incubation time. According to our results, it may be safe to narrow the antimicrobial spectrum to solely target Gram-positive bacteria when the culture is still negative after 48 h, and to cease antimicrobial therapy when the culture is still negative after 72 h in clinically well infants. PMID:21163823

Guerti, Khadija; Devos, Helena; Ieven, Margareta M; Mahieu, Ludo M

2011-04-01

137

Ultra-high throughput real-time instruments for capturing fast signals and rare events  

Science.gov (United States)

Wide-band signals play important roles in the most exciting areas of science, engineering, and medicine. To keep up with the demands of exploding internet traffic, modern data centers and communication networks are employing increasingly faster data rates. Wide-band techniques such as pulsed radar jamming and spread spectrum frequency hopping are used on the battlefield to wrestle control of the electromagnetic spectrum. Neurons communicate with each other using transient action potentials that last for only milliseconds at a time. And in the search for rare cells, biologists flow large populations of cells single file down microfluidic channels, interrogating them one-by-one, tens of thousands of times per second. Studying and enabling such high-speed phenomena pose enormous technical challenges. For one, parasitic capacitance inherent in analog electrical components limits their response time. Additionally, converting these fast analog signals to the digital domain requires enormous sampling speeds, which can lead to significant jitter and distortion. State-of-the-art imaging technologies, essential for studying biological dynamics and cells in flow, are limited in speed and sensitivity by finite charge transfer and read rates, and by the small numbers of photo-electrons accumulated in short integration times. And finally, ultra-high throughput real-time digital processing is required at the backend to analyze the streaming data. In this thesis, I discuss my work in developing real-time instruments, employing ultrafast optical techniques, which overcome some of these obstacles. In particular, I use broadband dispersive optics to slow down fast signals to speeds accessible to high-bit depth digitizers and signal processors. I also apply telecommunication multiplexing techniques to boost the speeds of confocal fluorescence microscopy. The photonic time stretcher (TiSER) uses dispersive Fourier transformation to slow down analog signals before digitization and processing. The act of time-stretching effectively boosts the performance of the back-end electronics and digital signal processors. The slowed down signals reach the back-end electronics with reduced bandwidth, and are therefore less affected by high-frequency roll-off and distortion. Time-stretching also increases the effective sampling rate of analog-to-digital converters and reduces aperture jitter, thereby improving resolution. Finally, the instantaneous throughputs of digital signal processors are enhanced by the stretch factor to otherwise unattainable speeds. Leveraging these unique capabilities, TiSER becomes the ideal tool for capturing high-speed signals and characterizing rare phenomena. For this thesis, I have developed techniques to improve the spectral efficiency, bandwidth, and resolution of TiSER using polarization multiplexing, all-optical modulation, and coherent dispersive Fourier transformation. To reduce the latency and improve the data handling capacity, I have also designed and implemented a real-time digital signal processing electronic backend, achieving 1.5 tera-bit per second instantaneous processing throughput. Finally, I will present results from experiments highlighting TiSER's impact in real-world applications. Confocal fluorescence microscopy is the most widely used method for unveiling the molecular composition of biological specimens. However, the weak optical emission of fluorescent probes and the tradeoff between imaging speed and sensitivity is problematic for acquiring blur-free images of fast phenomena and cells flowing at high speed. Here I introduce a new fluorescence imaging modality, which leverages techniques from wireless communication to reach record pixel and frame rates. Termed Fluorescence Imaging using Radio-frequency tagged Emission (FIRE), this new imaging modality is capable of resolving never before seen dynamics in living cells - such as action potentials in neurons and metabolic waves in astrocytes - as well as performing high-content image assays of cells and particles in high-speed flow.

Buckley, Brandon Walter

138

A novel fast neutron time-of-flight system  

International Nuclear Information System (INIS)

A time-of-flight spectrometer for the measurement of 14 MeV neutron elastic and inelastic differential cross sections is described which was devised to provide a flight path of 13 m within a restricted laboratory space. Instead of rotating the neutron detector around the scattering sample, the scattering sample was rotated around the neutron producing target with the neutron detector fixed. By taking the line of the beam incident on the neutron producing target as the axis of rotation of the scattering sample a constant reaction angle was maintained for the neutrons incident on the sample and hence a constant incident energy. This provided a simple way of working with a fixed neutron detector. Aspects of the system may be of interest to others constrained to work within a restricted space or seeking the advantage of having the neutron detector in a fixed position. The system is assessed relative to more conventional configurations. (orig.)

1990-12-10

139

Achieving a response from fast-growing companies: the case of Slovenian gazelles  

Directory of Open Access Journals (Sweden)

Full Text Available Non-mandatory business surveys generally suffer from low response rates and potential non-response bias. Achieving a response is most problematic in small- and medium-sized enterprises because of their scarce human resources. The problem becomes exacerbated in fast-growing companies – ‘gazelles’. The paper addresses the effectiveness of data collection efforts to achieve a response among the top Slovenian gazelles in 2008. We analyse the impact on response rates and data quality. Finally, we look for evidence of non-response bias.

Aleša Lotri? Dolinar

2009-11-01

140

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

1999-02-01

 
 
 
 
141

Signal and Noise Analysis in TRION -Time-Resolved Integrative Optical Fast Neutron Detector  

Digital Repository Infrastructure Vision for European Research (DRIVER)

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In...

Vartsky, D.; Feldman, G.; Mor, I.; Goldberg, M. B.; Bar, D.; Dangendorf, V.

2008-01-01

142

Ultra Fast Timing Measurements at $^{78}$Ni and $^{132}$Sn  

CERN Multimedia

We propose to measure level lifetimes in the exotic nuclei of $^{81}$Ga and $^{80}$Ga in the vicinity of $^{78}$Ni and of $^{135}$Sb and $^{134}$Sb above $^{132}$Sn by the time-delayed technique. These are relatively simple nuclear systems with a few particles and/or holes outside of the doubly-magic core thus can be treated rather precisely within the shell model. The anticipated new structure information on these nuclei, and in particular the lifetime results will put constrains on the model parameters and will serve to verify their predictions. The selected nuclei are some of the most exotic ones just above $^{78}$Ni or $^{132}$Sn, where the transition rates can be studied at present. Of the strongest interest is the nucleus of $^{81}$Ga, which has only 3 valence protons outside of $^{78}$Ni with the lowest proton orbits being $\\emph{p}_{3/2}$ and $\\emph{f}_{5/2}$. The Ml transition between these states, although allowed by the selection rules, should be $\\emph{l}$-forbidden thus very slow. This should giv...

Hoff, P

2002-01-01

143

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

2011-12-01

144

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. PMID:22755655

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

2012-06-01

145

Time response of CVD diamond film detectors  

International Nuclear Information System (INIS)

The speed of a CVD diamond detector is faster than a Si-PIN detector with the same size. Two CVD diamond film detectors of different size and quality are made and factors which may affect the time response of a CVD diamond film detector are discussed through theoretic and experimental researches. The area and thickness of the film are the main factors. And the impurities and traps in the film slow the detectors. CVD diamond detectors for ns pulsed radiation detection can be made by using high quality diamond films with the proper size. (authors)

2007-11-05

146

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

147

Improvement of photomultiplier tube voltage divider ORTEC 269 for fast neutron time-of-flight spectrometer  

International Nuclear Information System (INIS)

Improvement of photomultiplier tube voltage divider ORTEC 269 for fast neutron time-of-flight spectrometer is described. As a result the performances of pulse-height, PSD (pulse shape discrimination) and timing resolution for neutron spectrometer have been greatly improved

1993-03-01

148

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

149

Fast Time and Space Parallel Algorithms for Solution of Parabolic Partial Differential Equations  

Science.gov (United States)

In this paper, fast time- and Space -Parallel agorithms for solution of linear parabolic PDEs are developed. It is shown that the seemingly strictly serial iterations of the time-stepping procedure for solution of the problem can be completed decoupled.

Fijany, Amir

1993-01-01

150

Adaptive responses of GLUT-4 and citrate synthase in fast-twitch muscle of voluntary running rats  

Science.gov (United States)

Glucose transporter (GLUT-4) protein, hexokinase, and citrate synthase (proteins involved in oxidative energy production from blood glucose catabolism) increase in response to chronically elevated neuromuscular activity. It is currently unclear whether these proteins increase in a coordinated manner in response to this stimulus. Therefore, voluntary wheel running (WR) was used to chronically overload the fast-twitch rat plantaris muscle and the myocardium, and the early time courses of adaptative responses of GLUT-4 protein and the activities of hexokinase and citrate synthase were characterized and compared. Plantaris hexokinase activity increased 51% after just 1 wk of WR, whereas GLUT-4 and citrate synthase were increased by 51 and 40%, respectively, only after 2 wk of WR. All three variables remained comparably elevated (+50-64%) through 4 wk of WR. Despite the overload of the myocardium with this protocol, no substantial elevations in these variables were observed. These findings are consistent with a coordinated upregulation of GLUT-4 and citrate synthase in the fast-twitch plantaris, but not in the myocardium, in response to this increased neuromuscular activity. Regulation of hexokinase in fast-twitch muscle appears to be uncoupled from regulation of GLUT-4 and citrate synthase, as increases in the former are detectable well before increases in the latter.

Henriksen, E. J.; Halseth, A. E.

1995-01-01

151

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

152

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

153

Formulation and optimization of fast dissolving intraoral drug delivery system for clobazam using response surface methodology.  

Science.gov (United States)

Clobazam is a newer 1,5-benzodiazepine used for the treatment of epilepsy. It is better tolerated and less sedating than other benzodiazepines. Absorption of the drug can be impacted by oral fast dissolving dosage form; this may have implications for epilepsy in pediatrics and those having difficulty in swallowing tablets/capsules resulting in improved patient compliance. The purpose of the present investigation was to formulate and optimize clobazam oro-dissolving tablets by direct compression method using response surface methodology (RSM). Oro-dispersible tablets of clobazam were prepared by direct compression method using crospovidone (2-6%) as a superdisintegrant, microcrystalline cellulose (MCC) (20-40%) was used as diluents along with directly compressible mannitol to enhance mouth feel. A 3(2) full factorial design was applied to investigate the combined effect of two formulation variables: amount of crospovidone and MCC over the independent variables disintegration time, wetting time and percent drug release. Disintegration time showed by all formulations was found to be in the range of 24.3-193 s based on evaluation parameters the formulation containing 6% of crospovidone and 30% of MCC showed promising performance against all other formulations. The results demonstrated that the RSM could efficiently be applied for the formulation of clobazam oro-dispersible tablets; therefore, constitute an advance in the management of epileptic attacks. PMID:24083203

Bala, Rajni; Khanna, Sushil; Pawar, Pravin K

2013-07-01

154

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

International Nuclear Information System (INIS)

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.

2009-09-01

155

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

156

Fast orthogonal-transform algorithms for multiresolution time-sequency signal decomposition and processing  

Science.gov (United States)

In this paper we present orthogonal transforms as a signal analysis and processing tool with the capability of variable multiresolution time-spectral decomposition of discrete signals. Our prime interest is in the representation of square summable sequences in terms of wavelet packet matrices used as discrete orthogonal systems, and we concentrate on the fast transform algorithms for such systems. We analyze polyphase and lattice-tree structures which are common for multiple block-size orthogonal transforms, multiresolution multirate filter banks, and wavelet packet transforms. The purpose of this present paper is to compare and contrast the wavelet packet based approach to the traditional techniques for fast orthogonal transform algorithms. We consider results from this technique that influence the design of filter banks and we indicate some results from lattice-structured filter banks which can be useful for the design of fast wavelet packet transform algorithms. A time-varying structure that is based on fast algorithms of orthogonal transforms and their orthogonal sub-transforms is presented. In this case, orthogonal bases consist of a finite collection of wavelet packets which provide a fairly rich family of orthogonal decompositions of the time-scale plane. In particular, the time- sequence plane representation, one of many possible time-spectral and time-scale plane representations is discussed.

Drygajlo, Andrzej

1993-11-01

157

FAST-RESPONSE ISOTOPIC ALPHA CONTINUOUS AIR MONITOR (CAM)  

Energy Technology Data Exchange (ETDEWEB)

The objective of this effort is to develop and test a novel Continuous Air Monitor (CAM) instrument for monitoring alpha-emitting radionuclides, using a technology that can be applied to Continuous Emission Monitoring (CEM) of thermal treatment system off gas streams. The CAM instrument will have very high alpha spectral resolution and provide real-time, on-line monitoring suitable for alerting workers of high concentrations of alpha-emitting radionuclides in the ambient air and for improved control of decontamination, dismantlement, and air emission control equipment. Base Phase I involves the design, development, and preliminary testing of a laboratory-scale instrument. Testing will initially be conducted using naturally-occurring radon progeny in ambient air. In the Optional Phase II, the Base Phase I instrument will be critically evaluated at the Lovelace Respiratory Research Institute (LRRI) with characterized plutonium aerosols; then an improved instrument will be built and field-tested at a suitable DOE site.

Keith D. Patch

2000-04-28

158

Concatenated Space-Time Block Coding with Asymmetric MPSK TCM for Fast Fading Channels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The field of concatenated space-time block coding (inner) with trellis coded modulation (outer) has recently attracted interest as a means of jointly considering the error correction coding gain and diversity gain possible without bandwidth expansion and power expansion over fading channels. In this research, a concatenated Space-Time Block Coding (STBC)with asymmetric MPSK TCM scheme, based on the design criteria for constructing concatenated space-time block coding with TCM for fast R...

2008-01-01

159

Hydrogel-based microactuators with remote-controlled locomotion and fast Pb2+-response for micromanipulation.  

Science.gov (United States)

Hydrogel-based microactuators that enable remote-controlled locomotion and fast Pb(2+)-response for micromanipulation in Pb(2+)-polluted microenvironment have been fabricated from quadruple-component double emulsions. The microactuators are Pb(2+)-responsive poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) microgels, each with an eccentric magnetic core for magnetic manipulation and a hollow cavity for fast Pb(2+)-response. Micromanipulation of the microactuators is demonstrated by using them for preventing Pb(2+)-leakage from microchannel. The microactuators can be remotely and precisely transported to the Pb(2+)-leaking site under magnetic guide, and then clog the microchannel with Pb(2+)-responsive volume swelling to prevent flowing out of Pb(2+)-contaminated solution. The proposed microactuator structure provides a potential and novel model for developing multifunctional actuators and sensors, biomimetic soft microrobots, microelectro-mechanical systems and drug delivery systems. PMID:23865475

Liu, Ying-Mei; Wang, Wei; Zheng, Wei-Chao; Ju, Xiao-Jie; Xie, Rui; Zerrouki, Djamal; Deng, Nan-Nan; Chu, Liang-Yin

2013-08-14

160

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

2008-10-01

 
 
 
 
161

Design of a fast response ZrCo bed  

Energy Technology Data Exchange (ETDEWEB)

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.

Shim, Myunghwa; Chung, Hongsuk; Jin, Haksoo; Lee, Jongkuk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yoshida, Hiroshi [Fusion Science Consultant, Ibakaki (Japan); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of); Song, Kyumin [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2008-10-15

162

Aroclor 1254 exposure reduces disease resistance and innate immune responses in fasted arctic charr  

Science.gov (United States)

To examine the immunological impacts of polychlorinated biphenyls (PCBs) in an environmentally relevant way, we orally contaminated Arctic charr (Salvelinus alpinus) with Aroclor 1254. After contamination, fish were either fed (0 and 100 mg Aroclor 1254 kg-1 fish wt) or fasted (0, 1, 10, and 100 mg kg-1) to mimic cycles of feeding-fasting experienced by Arctic animals. After four months, PCB concentrations in muscle were the same in fasted and fed fish; however, PCBs in kidneys of fed fish were 33 to 50% of those in fasted fish. Arctic charr were exposed to Aeromonas salmonicida, the bacteria responsible for furunculosis, by cohabitation with infected conspecifics. Fasted fish had a significant trend toward lower survival with higher dose of PCBs - from 68% in controls to 48% in treatment involving 100 mg kg-1. Independent of PCB contamination, fed fish had the lowest survival; we attribute this to stress associated with establishing and maintaining feeding hierarchies. A significant decrease in the activity of lysozyme was observed in skin mucus, as was hemagglutination ability of a putative rhamnose lectin in fasted, but not in fed, PCB-treated fish. These results demonstrate the immunosuppressive effects of PCBs on Arctic charr, and they illustrate the importance of considering environmentally relevant nutritional status in ecotoxicological studies.

Maule, A. G.; Jorgensen, E. H.; Vijayan, M. M.; Killie, J. -E. A.

2005-01-01

163

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

164

A measurement of the fast luminescent decay time of P-15 phosphor.  

Science.gov (United States)

The fast decay time of a 3900-A spectral component of an electron-beam excited P-15 phosphor has been measured using a delayed coincidence technique. The result, 1.04 nsec plus or minus nearly 2%, is in good agreement with previous estimates.

Sutton, J. F.

1972-01-01

165

Digital timing walk correction and its application to a time-dependent fast neutron energy spectrum measurement  

International Nuclear Information System (INIS)

Timing walk is the pulse height dependent shift in the mean time at which a discriminator triggers. If there is any such walk, when a pulse height spectrum is sampled over short time intervals, as is the case in time-dependent fast neutron spectroscopy, severe distortions to the pulse height spectrum can occur. Results are given of measurements of walk and consequent pulse height spectrum distortions. A procedure which uses an on-line computer to compensate for walk is described and its effectiveness evaluated. A study is made of distortions of time-dependent spectra, resulting from noise which broadens time resolution at low pulse amplitudes. The reduction of timing walk to +- 35 ps is illustrated for a time-dependent neutron energy spectrum measurement. (orig.)

1980-11-15

166

Enhanced response of the regular networks to local signals in presence of a fast impurity  

CERN Document Server

We consider an array of inductively coupled Josephson junctions with a fast impurity (a junction with a smaller value of critical current), and study the consequences of imposing a small amplitude periodic signal at some point in the array. We find that when external signal is imposed at the impurity, the response of the array is boosted and a small amplitude signal can be detected throughout the array. When the signal is imposed elsewhere, minor effects is seen on the dynamics of the array. The same results have been also seen in presence of a single fast spiking neuron in a chain of diffusively coupled FitzHugh-Nagumo neurons.

Valizadeh, Alireza

2012-01-01

167

Fast MCMC sampling for Markov jump processes and continuous time Bayesian networks  

CERN Multimedia

Markov jump processes and continuous time Bayesian networks are important classes of continuous time dynamical systems. In this paper, we tackle the problem of inferring unobserved paths in these models by introducing a fast auxiliary variable Gibbs sampler. Our approach is based on the idea of uniformization, and sets up a Markov chain over paths by sampling a finite set of virtual jump times and then running a standard hidden Markov model forward filtering-backward sampling algorithm over states at the set of extant and virtual jump times. We demonstrate significant computational benefits over a state-of-the-art Gibbs sampler on a number of continuous time Bayesian networks.

Rao, Vinayak

2012-01-01

168

Fast response measurements of the dispersion of nanoparticles in a vehicle wake and a street canyon  

Science.gov (United States)

The distributions of nanoparticles (below 300 nm in diameter) change rapidly after emission from the tail pipe of a moving vehicle due to the influence of transformation processes. Information on this time scale is important for modelling of nanoparticle dispersion but is unknown because the sampling frequencies of available instruments are unable to capture these rapid processes. In this study, a fast response differential mobility spectrometer (Cambustion Instruments DMS500), originally designed to measure particle number distributions (PNDs) and concentrations in engine exhaust emissions, was deployed to measure particles in the 5-1000 nm size range at a sampling frequency of 10 Hz. This article presents results of two separate studies; one, measurements along the roadside in a Cambridge (UK) street canyon and, two, measurements at a fixed position (20 cm above road level), centrally, in the wake of a single moving diesel-engined car. The aims of the first measurements were to test the suitability and recommend optimum operating conditions of the DMS500 for ambient measurements. The aim of the second study was to investigate the time scale over which competing influences of dilution and transformation processes (nucleation, condensation and coagulation) affect the PNDs in the wake of a moving car. Results suggested that the effect of transformation processes was nearly complete within about 1 s after emission due to rapid dilution in the vehicle wake. Furthermore, roadside measurements in a street canyon showed that the time for traffic emissions to reach the roadside in calm wind conditions was about 45 ± 6 s. These observations suggest the hypothesis that the effects of transformation processes are generally complete by the time particles are observed at roadside and the total particle numbers can then be assumed as conserved. A corollary of this hypothesis is that complex transformation processes can be ignored when modelling the behaviour of nanoparticles in street canyons once the very near-exhaust processes are complete.

Kumar, Prashant; Robins, Alan; Britter, Rex

2009-12-01

169

Fast and Slow Responses of the South Asian Monsoon System to Anthropogenic Aerosols  

Energy Technology Data Exchange (ETDEWEB)

Using a global climate model with fully predictive aerosol life cycle, we investigate the fast and slow responses of the South Asian monsoon system to anthropogenic aerosol forcing. Our results show that the feedbacks associated with sea surface temperature (SST) change caused by aerosols play a more important role than the aerosol's direct impact on radiation, clouds and land surface (rapid adjustments) in shaping the total equilibrium climate response of the monsoon system to aerosol forcing. Inhomogeneous SST cooling caused by anthropogenic aerosols eventually reduces the meridional tropospheric temperature gradient and the easterly shear of zonal winds over the region, slowing down the local Hadley cell circulation, decreasing the northward moisture transport, and causing a reduction in precipitation over South Asia. Although total responses in precipitation are closer to the slow responses in general, the fast component dominates over land areas north of 25°N. Our results also show an east-west asymmetry in the fast responses to anthropogenic aerosols causing increases in precipitation west of 80°E but decreases east of it.

Ganguly, Dilip; Rasch, Philip J.; Wang, Hailong; Yoon, Jin-Ho

2012-09-25

170

A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air  

Science.gov (United States)

Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in ambient air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C9-C15 BVOC composition of single plant emissions may be characterised within a 14.5 min analysis time. Moreover, in-situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an 11.7 min chromatographic separation time (increasing to 19.7 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). These analysis times potentially allow for a twofold to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in-situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC (OBVOC) linalool in ambient air. During this field deployment within a suburban forest ~30 km west of central Tokyo, Japan, the Fast-GC limit of detection with respect to monoterpenes was 4-5 ppt, and the agreement between Fast-GC and PTR-MS derived total monoterpene mixing ratios was consistent with previous GC/PTR-MS comparisons. The measurement uncertainties associated with the Fast-GC quantification of monoterpenes are ? 12%, while larger uncertainties (up to ~25%) are associated with the OBVOC and sesquiterpene measurements.

Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

2014-05-01

171

Web Service Response Time Monitoring: Architecture and Validation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 accom...

2012-01-01

172

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 vola...

Fliess, Michel; Join, Ce?dric

2008-01-01

173

Thermal response of a field emitter subjected to ultra-fast laser illumination  

International Nuclear Information System (INIS)

Using an ultra-fast laser assisted atom probe, the temporal evolution of the temperature of a tungsten field emitter subjected to illumination is studied. The combination of pump probe experiments and evaporation rate measurements is used to estimate the duration of field evaporation, the induced peak temperature and the cooling time. The main conclusion of the measurements is that, despite a significant heating of the tip by the laser pulse, the cooling time is anomalously fast, below 0.5 ns. Hence, thermal effects are considered to play a major role in ion emission in contrast to conclusions of our previous works. It is shown that the really fast anomalous cooling rate can only be related to a confined heating zone at the tip apex smaller than the wavelength of the laser.

2009-06-21

174

An efficient fast response and high-gain solar-blind flexible ultraviolet photodetector employing hybrid geometry  

Science.gov (United States)

We report high performance flexible hybrid ultraviolet photodetector with solar-blind sensitivity using nanocomposite film of plasma polymerized aniline-titanium dioxide. A facile solvent-free plasma technique is used to synthesize superior quality hybrid material with high yield. The hybrid photodetector exhibited high photoconductive gain of the order of ˜105 and fast speed with response and recovery time of 22.87 ms and 34.23 ms. This is an excellent result towards getting a balance in the response speed and photoconductive gain trade-off of the photodetectors reported so far. In addition, the device has the advantages of enhanced photosensitivity ((Ilight - Idark)/Idark) of the order of ˜102 and high responsivity of ˜104 AW-1. All the merits substantiates that, to prepare hybrid material, plasma based method holds potential to be an easy way for realizing large scale nanostructured photodetectors for practical applications.

Hussain, Amreen A.; Pal, Arup R.; Patil, Dinkar S.

2014-05-01

175

Investigaing the response of hot QCD matter to fast partons using bare thermal perturbation theory  

Science.gov (United States)

The response of hot QCD matter to energetic partons has gained tremendous interest in light of two- and three- particle correlation measurements from heavy-ion collisions at RHIC that show a conical emission structure. While the association of this conical structure with Mach cone formation is uncertain, investigation of the medium response to fast partons is still very relevant. Within the perturbative framework, the traditional approach to such an investigation has been to treat the fast parton as a source of soft external color fields which perturb an otherwise thermal medium. In that approach, the appropriate formalism is the hard thermal loop effective theory. However, when the external fields generated by a fast parton are of the order of the temperature or higher, a different approach is needed. I will here present an approach for such a situation, in which bare thermal perturbation theory is used to evaluate the thermal average of the energy-momentum tensor. I will present results for components of the energy-momentum tensor for a gluonic medium in the presence of a fast parton.

Neufeld, R. B.

2010-11-01

176

Observation of very fast response signals from Pb absorber coupled transition edge sensor gamma-ray microcalorimeter  

Energy Technology Data Exchange (ETDEWEB)

We are developing a gamma-ray microcalorimeter for Positron Annihilation Spectroscopy. Our detector composed of a transition edge sensor (TES) thermometer and an epoxy coupled bulk Pb absorber has been reported an energy resolution of 4.7 keV FWHM at 662 keV with a tens of milliseconds long response time. To enhance the detector properties, we designed a new attachment method in the focus of improving the thermal coupling between the absorber and the TES. In the new design, we created epoxy-posts both on the TES film and on the absorber, and then they were connected together using an epoxy-dot put on the epoxy-post on the absorber. Measured current signal of this epoxy-post TES gamma-ray detector showed an ultra fast response with 80 {mu}s fall time.

Damayanthi, R.M.T., E-mail: thushara@sophie.q.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Ohno, M.; Hatakeyama, S.; Takahashi, H. [Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Maehata, K.; Yasumune, T.; Iyomoto, N. [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

2012-11-01

177

Fast monitoring of epileptic seizures using recurrence time statistics of electroencephalography  

Directory of Open Access Journals (Sweden)

Full Text Available Epilepsy is one of the most common disorders of the brain. Currently, determination of epileptic seizures often involves tedious, time-consuming visual inspection of electroencephalography (EEG data by medical experts. To better monitor seizures and make medications more effective, we propose a recurrence time based approach to characterize brain electrical activity. Recurrence times have a number of distinguished properties that make it very effective for forwarning epileptic seizures as well as studying propagation of seizures: 1 recurrence times amount to periods of periodic signals, 2 recurrence times are closely related to information dimension, Lyapunov exponent, and Kolmogorov entropy of chaotic signals, 3 recurrence times embody Shannon and Renyi entropies of random fields, and 4 recurrence times can readily detect bifurcation-like transitions in dynamical systems. In particular, property 4 dictates that unlike many other nonlinear methods, recurrence time method does not require the EEG data be chaotic and/or stationary. Moreover, the method only contains a few parameters that are largely signal-independent, and hence, is very easy to use. The method is also very fast—it is fast enough to on-line process multi-channel EEG data with a typical PC. Therefore, it has the potential to be an excellent candidate for real-time monitoring of epileptic seizures in a clinical setting.

JianboGao

2013-10-01

178

Fast monitoring of epileptic seizures using recurrence time statistics of electroencephalography.  

Science.gov (United States)

Epilepsy is a relatively common brain disorder which may be very debilitating. Currently, determination of epileptic seizures often involves tedious, time-consuming visual inspection of electroencephalography (EEG) data by medical experts. To better monitor seizures and make medications more effective, we propose a recurrence time based approach to characterize brain electrical activity. Recurrence times have a number of distinguished properties that make it very effective for forewarning epileptic seizures as well as studying propagation of seizures: (1) recurrence times amount to periods of periodic signals, (2) recurrence times are closely related to information dimension, Lyapunov exponent, and Kolmogorov entropy of chaotic signals, (3) recurrence times embody Shannon and Renyi entropies of random fields, and (4) recurrence times can readily detect bifurcation-like transitions in dynamical systems. In particular, property (4) dictates that unlike many other non-linear methods, recurrence time method does not require the EEG data be chaotic and/or stationary. Moreover, the method only contains a few parameters that are largely signal-independent, and hence, is very easy to use. The method is also very fast-it is fast enough to on-line process multi-channel EEG data with a typical PC. Therefore, it has the potential to be an excellent candidate for real-time monitoring of epileptic seizures in a clinical setting. PMID:24137126

Gao, Jianbo; Hu, Jing

2013-01-01

179

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

International Nuclear Information System (INIS)

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 (). - Highlights: ? GEANT4 has been used to model organic scintillators response to neutrons up to 5 MeV. ? The response of 2?×2? and 5?×5? BC501A detectors has been parameterized with simple functions. ? Parameterization will allow the modeling of neutron Time of Flight measurements with MCNP using tools based on CERN's ROOT.

2012-07-01

180

Effect of fasting on the transit time of 144Ce in the mouse gut  

International Nuclear Information System (INIS)

Our work with G.I. absorption of actinide elements indicates greater absorption by fasted animals than by animals on regular diets (Weiss and Walburg, undated). Residence time of a metallic compound in the gut may be an important factor influencing G.I. absorption. Cerium-144 (III) chloride was administered by gavage to fasted mice and to mice on regular feed. The G.I. tract was excised, cut into sections, and the activity of each section determined as a function of time after dosing. Our results indicate rapid transit of 144CeCl3 along the empty mouse gut. One hour after dosing, about half the Ce is in the cecal contents; about 40% remains in stomach contents. Twelve hours after dosing, only about 2% remains in the cecum; by 16 hours, almost the entire dose has been cleared from the intestine. Transit times in mice with stomach and intestines containing food were 12 hours longer than in fasted mice. These results lead to the conclusion that factors other than G.I. residence time determine G.I. absorption of actinides in mice

1978-06-01

 
 
 
 
181

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

International Nuclear Information System (INIS)

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)

1992-03-18

182

Fast-ion response to energetic-particle-driven MHD activity in Heliotron J  

International Nuclear Information System (INIS)

In Heliotron J, low magnetic shear configuration, instabilities with frequency chirping in the frequency range of Alfven eigenmodes have been observed in tangentially injected neutral beam plasmas. These modes are induced by energetic-particle driven magnetohydrodynamic (MHD) instabilities such as global Alfven eigenmode or energetic particle mode. A hybrid directional Langmuir probe system has been installed into Heliotron J to investigate the response of fast-ion fluxes to the MHD modes. A high coherent response of the ion flux to the bursting modes has been observed not only by the co-directed probe but also by the counter-directed one. A linear correlation between the response of the co-directed ion flux and the mode amplitude has been found. The radial profile of the response of the co-directed ions has decreased with the minor radius and has not been obtained significantly outside last closed flux surface. These results indicate that the fast-ion response is due to a resonant convective oscillation. The ion flux response of the counter-directed probe has appeared in the growth phase of the mode burst. Its phase relation is different from that of co-directed one and magnetic probe located at the Heliotron J vacuum vessel. Two candidates of the detected ion flux of the counter-directed probe have been discussed. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

2010-08-01

183

Fast Response to Infection Spread and Cyber Attacks on Large-Scale Networks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a strategy for designing fast methods of response to cyber attacks and infection spread on complex weighted networks. In these networks, nodes can be interpreted as primitive elements of the system, and weighted edges reflect the strength of interaction among these elements. The proposed strategy belongs to the family of multiscale methods whose goal is to approximate the system at multiple scales of coarseness and to obtain a solution of microscopic scale by comb...

Leyffer, Sven; Safro, Ilya

2012-01-01

184

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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&l...

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

2012-01-01

185

Effects of spacetime curvature and rotation on arrival times of pulses from fast pulsars  

International Nuclear Information System (INIS)

General relativistic effects, due to spacetime curvature and rotation, on the arrival times of pulsar signals are investigated using a rotationally perturbed spherical metric. For the millisecond pulsar PSR 1937 + 214, the advancement in arrival time (assuming the usual polar cap model for emission mechanism and a radius-to-frequency mapping) due to these effects is found to be nontrivial. The results are compared with recent multifrequency timing measurements on PSR 1937 + 214, and the implications regarding emission region thickness and emission mechanism for fast pulsars are discussed. 19 references

1986-01-01

186

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

International Nuclear Information System (INIS)

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

1992-10-27

187

Fast and slow timescales in the tropical low-cloud response to increasing CO2 in two climate models  

Science.gov (United States)

To obtain physical insights into the response and feedback of low clouds (C l ) to global warming, ensemble 4 × CO2 experiments were carried out with two climate models, the Model for Interdisciplinary Research on Climate (MIROC) versions 3.2 and 5. For quadrupling CO2, tropical-mean C l decreases, and hence, acts as positive feedback in MIROC3, whereas it increases and serves as negative feedback in MIROC5. Three time scales of tropical-mean C l change were identified—an initial adjustment without change in the global-mean surface air temperature, a slow response emerging after 10-20 years, and a fast response in between. The two models share common features for the former two changes in which C l decreases. The slow response reflects the variability of C l associated with the El Niño-Southern Oscillation in the control integration, and may therefore be constrained by observations. However, the fast response is opposite in the two models and dominates the total response of C l . Its sign is determined by a subtle residual of the C l increase and decrease over the ascending and subsidence regions, respectively. The regional C l increase is consistent with a more frequent occurrence of a stable condition, and vice versa, as measured by lower-tropospheric stability (LTS). The above frequency change in LTS is similarly found in six other climate models despite a large difference in both the mean and the changes in the low-cloud fraction for a given LTS. This suggests that the response of the thermodynamic constraint for C l to increasing CO2 concentrations is a robust part of the climate change.

Watanabe, Masahiro; Shiogama, Hideo; Yoshimori, Masakazu; Ogura, Tomoo; Yokohata, Tokuta; Okamoto, Hajime; Emori, Seita; Kimoto, Masahide

2012-10-01

188

Fast response of lake plankton and nutrients to river inundations on floodplain lakes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Key variables in ecosystems tend to operate on widely different time-scales. These time-scales become relevant when a disturbance rocks the ecosystem. Here we try to explain the fast dynamics of plankton and nutrients in the water column of floodplain lakes after disturbances (inundations). We take advantage of natural experiments, that is occasional massive overflow of floodplain lakes with river water. We sampled 10 lakes in two floodplains along the Dutch river Waal monthly for 3 years, ca...

Roozen, F. C. J. M.; Peeters, E. T. H. M.; Roijackers, R. M. M.; Wyngaert, I. J. J.; Wolters, H.; Coninck, H. C.; Ibelings, B. W.; Buijse, A. D.; Scheffer, M.

2008-01-01

189

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

CERN Document Server

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

190

A Fast-Time Simulation Environment for Airborne Merging and Spacing Research  

Science.gov (United States)

As part of NASA's Distributed Air/Ground Traffic Management (DAG-TM) effort, NASA Langley Research Center is developing concepts and algorithms for merging multiple aircraft arrival streams and precisely spacing aircraft over the runway threshold. An airborne tool has been created for this purpose, called Airborne Merging and Spacing for Terminal Arrivals (AMSTAR). To evaluate the performance of AMSTAR and complement human-in-the-loop experiments, a simulation environment has been developed that enables fast-time studies of AMSTAR operations. The environment is based on TMX, a multiple aircraft desktop simulation program created by the Netherlands National Aerospace Laboratory (NLR). This paper reviews the AMSTAR concept, discusses the integration of the AMSTAR algorithm into TMX and the enhancements added to TMX to support fast-time AMSTAR studies, and presents initial simulation results.

Bussink, Frank J. L.; Doble, Nathan A.; Barmore, Bryan E.; Singer, Sharon

2005-01-01

191

Preparation and properties of fast temperature-responsive soy protein/PNIPAAm IPN hydrogels  

Directory of Open Access Journals (Sweden)

Full Text Available The interpenetrating polymer network of fast temperature-responsive hydrogels based on soy protein and poly(N-isopropylacrylamide were successfully prepared using the sodium bicarbonate (NaHCO3 solutions as the reaction medium. The structure and properties of the hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermal gravimetric analysis. The swelling and deswelling kinetics were also investigated in detail. The results have shown that the proposed hydrogels had high porous structure, good miscibility and thermal stability, and fast temperature responsivity. The presence of NaHCO3 had little effect on the volume phase transition temperature (VPTT of the hydrogels, and the VPTTs were at about 32°C. Compared with the traditional hydrogels, the proposed hydrogels had much faster swelling and deswelling rate. The swelling mechanism of the hydrogels was the non-Fickian diffusion. This fast temperature-responsive hydrogels may have potential applications in the field of biomedical materials.

Liu Yong

2014-01-01

192

Timing resolution of fast neutron and gamma counting with plastic microchannel plates  

International Nuclear Information System (INIS)

The performance of novel plastic Microchannel plates (MCPs) with nano-engineered conduction and emission films have been shown to match the performance of conventional glass MCPs, widely used in image intensifying and event counting devices. In this paper we investigate the timing resolution of event detection with a 5 mm-thick polymethyl methacrylate (PMMA) microchannel plate with 50 ?m circular pores hexagonally packed at 70 ?m center-to-center spacing, which was developed for fast neutron detection. A detector consisting of the PMMA plastic MCP followed by a chevron stack of conventional glass MCPs for event multiplication was used in the timing experiments. The resolution of event counting was measured with Co-60 (1.17, 1.33 MeV ?) source. The timing accuracy was derived from the time difference of event detection with plastic MCP and a detector with liquid scintillator (BC519) coupled to a photomultiplier tube. The measured ?4 ns FWHM timing accuracy of gamma photon counting agrees well with the results of our predictions performed with the help of a fully 3-dimensional model of the MCP amplification process. The same model and measurements of photon detection with conventional glass MCPs indicate that substantially better (sub-ns) accuracy can be achieved with smaller pores. Although we could not directly measure the timing accuracy of fast neutron detection with our plastic MCP due to the time of flight limitation of non-monoenergetic source the fast neutron timing resolution should be on the same scale due to the similarity of amplification process once the secondary electrons are produced within a pore.

2011-12-11

193

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

Energy Technology Data Exchange (ETDEWEB)

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).

Mine, Shun-ichi; Tokushuku, Katsuo; Yamada, Sakue

1994-09-01

194

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

Energy Technology Data Exchange (ETDEWEB)

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. ((orig.)).

Mine, S.I. [Tokyo Univ. (Japan). Inst. for Nuclear Study; Tokushuku, K. [Tokyo Univ. (Japan). Inst. for Nuclear Study; Yamada, S. [Tokyo Univ. (Japan). Inst. for Nuclear Study

1995-04-21

195

Development of a fast time-to-digital converter 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. ((orig.))

1995-04-21

196

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

197

Time dependent solutions of the Fokker-Planck equation for fast fusion ions  

International Nuclear Information System (INIS)

Approximate time dependent solutions for the Fokker-Planck equation for fast fusion ions from an isotropic, monoenergetic source are presented, for the problem of D - T - He3 reactions. The equations include the effect of diffusion, which is particularly noticeable in the distribution of particles of lower energy and in the formation of a tail of particles with energy higher than that of the source. (Author)

1990-07-16

198

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)

1968-04-01

199

Dispersion of Response Times Reveals Cognitive Dynamics  

Science.gov (United States)

Trial-to-trial variation in word-pronunciation times exhibits 1/f scaling. One explanation is that human performances are consequent on multiplicative interactions among interdependent processes-interaction dominant dynamics. This article describes simulated distributions of pronunciation times in a further test for multiplicative interactions and…

Holden, John G.; Van Orden, Guy C.; Turvey, Michael T.

2009-01-01

200

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

2001-05-01

 
 
 
 
201

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

CERN Document Server

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

202

A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives  

International Nuclear Information System (INIS)

AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at ?10-50 Hz and emits ?106n/pulse at a peak current of 100 kA. Both sources emit 2.45±0.1 MeV(DD) neutron pulses of ?25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is 3 in volume.

2011-12-13

203

A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives  

Science.gov (United States)

AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at ~10-50 Hz and emits ~106n/pulse at a peak current of 100 kA. Both sources emit 2.45+/-0.1 MeV (DD) neutron pulses of ~25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm3 in volume.

Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

2011-12-01

204

A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives  

Energy Technology Data Exchange (ETDEWEB)

AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at {approx}10-50 Hz and emits {approx}10{sup 6}n/pulse at a peak current of 100 kA. Both sources emit 2.45{+-}0.1 MeV(DD) neutron pulses of {approx}25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm{sup 3} in volume.

Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert [Alameda Applied Sciences Corporation, 3077 Teagarden Street, San Leandro, CA 94577 (United States); Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Lane, Stephen [NSF Center for Biophotonics and School of Medicine, University of California Davis, Sacramento CA, 95817 (United States)

2011-12-13

205

Using Response Times for Item Selection in Adaptive Testing  

Science.gov (United States)

Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a second-level model for the distribution of the…

van der Linden, Wim J.

2008-01-01

206

Time-structure of thermal neutron leakage from fast and slow moderators for spallation neutron sources  

International Nuclear Information System (INIS)

The dwell-times of neutrons slowed down either in small polyethylene moderators or a large D"2O volume have been measured. The fast neutrons have been produced by bombarding lead, lead-bismuth, depleted uranium and tungsten targets of slab or cylindrical shape with short pulses of 490 MeV protons. Lead and beryllium reflectors have been employed for the rectangular shaped grooved polyethylene moderators. The geometry-adapted (jagged) polyethylene moderators used with the cylindrical target have been measured only in D"2O-reflected configuration. The essential result of the numerical analysis of about 40 target-moderator-reflector configurations tested is that for the fast (light hydrogen) moderators the most intense flux component decays in 100 ?s or less

1983-01-01

207

Fast and Practical Head Tracking in Brain Imaging with Time-of-Flight Camera  

DEFF Research Database (Denmark)

This paper investigates the potential use of Time-of-Flight cameras (TOF) for motion correction in medical brain scans. TOF cameras have previously been used for tracking purposes, but recent progress in TOF technology has made it relevant for high speed optical tracking in high resolution medical scanners. Particularly in MRI and PET, the newest generation of TOF cameras could become a method of tracking small and large scale patient movement in a fast and user friendly way required in clinical environments. We present a novel methodology for fast tracking from TOF point clouds without the need of expensive triangulation and surface reconstruction. Tracking experiments with a motion controlled head phantom were performed with a translational tracking error below 2mm and a rotational tracking error below 0:5.

Wilm, Jakob; Olesen, Oline Vinter

2013-01-01

208

Fast and practical head tracking in brain imaging with Time-of-Flight camera  

DEFF Research Database (Denmark)

This paper investigates the potential use of Time-of-Flight cameras (TOF) for motion correction in medical brain scans. TOF cameras have previously been used for tracking purposes, but recent progress in TOF technology has made it relevant for high speed optical tracking in high resolution medical scanners. Particularly in MRI and PET, the newest generation of TOF cameras could become a method of tracking small and large scale patient movement in a fast and user friendly way required in clinical environments. We present a novel methodology for fast tracking from TOF point clouds without the need of expensive triangulation and surface reconstruction. Tracking experiments with a motion controlled head phantom were performed with a translational tracking error below 2mm and a rotational tracking error below 0.5°.

Wilm, Jakob; Olesen, Oline Vinter

2013-01-01

209

Sputter ion pump based real time steam generator leak detection system for Fast Breeder Test Reactor  

International Nuclear Information System (INIS)

The energy produced in Fast Breeder Test Reactor (FBTR) is transferred to feed water for generating superheated steam in once-through shell and tube type countercurrent steam generator (SG). Sodium and water/steam flow in shell and tube side respectively are separated by thin-walls of ferritic steel tubes. Material defects in these tubes can lead to leakage of water/steam into sodium, resulting in sodium water reactions leading to undesirable consequences. Detection of a leak at its inception, therefore, is important for the safe and reliable operation of the reactor. Monitoring hydrogen in sodium, produced during reaction of sodium with the leaked water or steam is a convenient way to accomplish this. This paper report the development of instrumentation using sputter ion pump and nickel diffuser for real time hydrogen detection in sodium for FBTR at Kalpakkam, which is the fore runner of Fast Reactor Technology in India. (author)

2005-03-01

210

Optimal output fast feedback in two-time scale control of flexible arms  

Science.gov (United States)

Control of lightweight flexible arms moving along predefined paths can be successfully synthesized on the basis of a two-time scale approach. A model following control can be designed for the reduced order slow subsystem. The fast subsystem is a linear system in which the slow variables act as parameters. The flexible fast variables which model the deflections of the arm along the trajectory can be sensed through strain gage measurements. For full state feedback design the derivatives of the deflections need to be estimated. The main contribution of this work is the design of an output feedback controller which includes a fixed order dynamic compensator, based on a recent convergent numerical algorithm for calculating LQ optimal gains. The design procedure is tested by means of simulation results for the one link flexible arm prototype in the laboratory.

Siciliano, B.; Calise, A. J.; Jonnalagadda, V. R. P.

1986-01-01

211

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

2007-12-01

212

Down-regulation of urinary AQP2 and unaffected response to hypertonic saline after 24 hours of fasting in humans  

DEFF Research Database (Denmark)

In rats, 24 hours of fasting impairs urinary concentrating ability by down-regulation of aquaporin-2 (AQP2). We tested the hypothesis that 24 hours of fasting in humans reduces the capability to form AQP2 and impairs the antidiuretic response to hypertonic saline infusion.

Starklint, Jørn; Bech, Jesper Nørgaard

2005-01-01

213

Measurement of heating laser injection time in a fast-ignition experiment  

Science.gov (United States)

The ability to measure the injection time of a heating laser synchronized to the imploded core plasma is very important in fast-ignition experiments. In this research, we demonstrate the successful measurement of the injection time using a new x-ray framing camera design. Thermal x-rays for imploded core measurement and hard x-rays for measurement of the heating laser injection time were discriminated using x-ray reflectors made of platinum. The measured hard x-ray signal was evaluated with numerical calculations and found to agree well with the calculated values. We have established a technique for estimating the heating laser injection time from the position of the peak intensity of the hard x-ray signal.

Koga, M.; Ishii, Y.; Shigemori, K.; Shiraga, H.; Azechi, H.

2014-04-01

214

Fast differential discriminator with time coupling for scintillation and semiconductor detectors  

International Nuclear Information System (INIS)

Fast differential discriminator with time fixation (DDTF) for a time-of-flight spectrometer of high resolution is developed. Principal flowsheet of DDTF containing a discriminator of upper level, discriminator of lower level, time fixation, delay circuit and priority discriminator is described. Principle of discriminator operation is based on the difference method of shaping of a bipolar signal when using integral circuit engineering. When placing the discriminator in the detector head envisaged is remote control of thresholds in 0.05-2.5 v range for lower threshold and 0.1-5 v for upper. DDTF time resolution amounts to 70 ns for 3 ns pulse front and 570 ns for 20 ns front

1980-09-19

215

The Importance of Responsibility in Times of Crisis  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper I would like to show the importance of the concept of responsibility as the foundation of ethics in times of crisis in particular in the fields of politics and economics in the modern civilisation marked by globalization and technological progres. I consider the concept of responsibility as the key notion in order to understand the ethical duty in a modern technological civilisation. We can indeed observe a moralization of the concept of responsibility going beyond a strict legal definition in terms of imputability. The paper begins by discussing the humanistic foundations of such a concept of responsibility. It treats the historical origins of responsibility and it relates this concept to the concept of accountability. On the basis of this historical determination of the concept I would like to present the definition of the concept of responsibility as fundamental ethical principle that has increasing importance as the foundation of the principles of governance in modern welfare states. In this context the paper discusses the extension of the concept of responsibility towards institutional or corporate responsibility where responsibility does not only concerns the responsibility of individuals but also deals with the responsibility of institutional collectivities. In this way the paper is based on the following structure : 1 The ethical foundation of the concept of responsibility 2 Responsibility in technological civilisation 3 Political responsibility for good governance in the welfare state 4 Social responsibility of business corporations in times of globalization 5 Conclusion and discussion : changed conditions of responsibility in modern times.

Jacob Dahl Rendtorff

2014-06-01

216

Development of a LaBr3(Ce Fast-timing Array for FAIR  

Directory of Open Access Journals (Sweden)

Full Text Available A ?-ray spectrometer with fast-timing capabilities, constructed of LaBr3(Ce:5% detectors, is under development for use at the future Facility for Anti-proton and Ion Research (FAIR. The physics aims of this device are to measure the half-lives of excited states in the region of ~50 ps to several ns, in exotic nuclei. Monte-Carlo simulations using the GEANT4 software package have determined the final design of this fast-timing array by calculating the full-energy peak efficiencies of several different detector geometries. The results of the simulated efficiencies for each configuration were used to calculate the timing precision. Consequently, an array of thirty six, ø3.8×5.1 cm cylindrical crystals was found to be the optimum configuration. The detectors were purchased and subsequently characterised, with each detector found to have intrinsic energy and timing resolutions of ~ 2.8 % (FWHM and ~ 210 ps (FWHM for the 1173 and 1332 keV decays from 60Co.

Roberts O.J.

2013-12-01

217

Development of a LaBr3(Ce) Fast-timing Array for FAIR  

International Nuclear Information System (INIS)

A ?-ray spectrometer with fast-timing capabilities, constructed of LaBr3(Ce:5%) detectors, is under development for use at the future Facility for Anti-proton and Ion Research (FAIR). The physics aims of this device are to measure the half-lives of excited states in the region of ?50 ps to several ns, in exotic nuclei. Monte-Carlo simulations using the GEANT4 software package have determined the final design of this fast-timing array by calculating the full-energy peak efficiencies of several different detector geometries. The results of the simulated efficiencies for each configuration were used to calculate the timing precision. Consequently, an array of thirty six, section 3.8 x 5.1 cm cylindrical crystals was found to be the optimum configuration. The detectors were purchased and subsequently characterised, with each detector found to have intrinsic energy and timing resolutions of ? 2.8 % (FWHM) and ? 210 ps (FWHM) for the 1173 and 1332 keV decays from 60Co. (authors)

2013-04-08

218

Signal and noise analysis in TRION—Time-Resolved Integrative Optical Fast Neutron detector  

Science.gov (United States)

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event-counting detectors where the signal-to-noise ratio is dependent only on the number of detected events (quantum noise), in an energy-integrating detector additional factors, such as the fluctuations in imparted energy, number of photoelectrons, system gain and other factors will contribute to the noise. The excess noise factor (over the quantum noise) due to these processes was 4.3, 2.7, 2.1, 1.9 and 1.9 for incident neutron energies of 2, 4, 7.5, 10 and 14 MeV, respectively. It is shown that, even under ideal light collection conditions, a fast neutron detection system operating in an integrative mode cannot be quantum-noise-limited due to the relatively large variance in the imparted proton energy and the resulting scintillation light distributions.

Vartsky, D.; Feldman, G.; Mor, I.; Goldberg, M. B.; Bar, D.; Dangendorf, V.

2009-02-01

219

Signal and noise analysis in TRION-Time-Resolved Integrative Optical Fast Neutron detector  

International Nuclear Information System (INIS)

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event-counting detectors where the signal-to-noise ratio is dependent only on the number of detected events (quantum noise), in an energy-integrating detector additional factors, such as the fluctuations in imparted energy, number of photoelectrons, system gain and other factors will contribute to the noise. The excess noise factor (over the quantum noise) due to these processes was 4.3, 2.7, 2.1, 1.9 and 1.9 for incident neutron energies of 2, 4, 7.5, 10 and 14 MeV, respectively. It is shown that, even under ideal light collection conditions, a fast neutron detection system operating in an integrative mode cannot be quantum-noise-limited due to the relatively large variance in the imparted proton energy and the resulting scintillation light distributions.

2009-02-01

220

Signal and noise analysis in TRION-Time-Resolved Integrative Optical Fast Neutron detector  

Energy Technology Data Exchange (ETDEWEB)

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event-counting detectors where the signal-to-noise ratio is dependent only on the number of detected events (quantum noise), in an energy-integrating detector additional factors, such as the fluctuations in imparted energy, number of photoelectrons, system gain and other factors will contribute to the noise. The excess noise factor (over the quantum noise) due to these processes was 4.3, 2.7, 2.1, 1.9 and 1.9 for incident neutron energies of 2, 4, 7.5, 10 and 14 MeV, respectively. It is shown that, even under ideal light collection conditions, a fast neutron detection system operating in an integrative mode cannot be quantum-noise-limited due to the relatively large variance in the imparted proton energy and the resulting scintillation light distributions.

Vartsky, D; Feldman, G; Mor, I; Goldberg, M B; Bar, D [Soreq NRC, 81800 Yavne (Israel); Dangendorf, V [Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig (Germany)], E-mail: david@soreq.gov.il

2009-02-15

 
 
 
 
221

Efficient allocation of heterogeneous response times in information spreading process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recently, the impacts of spatiotemporal heterogeneities of human activities on spreading dynamics have attracted extensive attention. In this paper, to study heterogeneous response times on information spreading, we focus on the susceptible-infected spreading dynamics with adjustable power-law response time distribution based on uncorrelated scale-free networks. We find that the stronger the heterogeneity of response times is, the faster the information spreading is in the e...

Cui, Ai-xiang; Wang, Wei; Tang, Ming; Fu, Yan; Liang, Xiaoming; Do, Younghae

2014-01-01

222

Modeling response times with latent variables: Principles and applications  

Directory of Open Access Journals (Sweden)

Full Text Available The introduction of the computer in psychological and educational testing has enabled us to record response times on test items in real time, without any interruption of the response process. This article reviews key principles for probabilistic modeling of these response times and discusses a hierarchical model that follows from the principles. It then shows the potential of the model for improving the current practices of item calibration, adaptive testing, controlling test speededness, and detection of cheating.

2011-09-01

223

Development of fast-response temperature sensitive poly (n-isopropyl acrylamide) hydrogel by electron beam irradiation  

International Nuclear Information System (INIS)

The potential of electron beam (EB) irradiation to synthesize thermally sensitive fast-response poly(n-isopropyl acrylamide) (PNIPAm) hydrogel has been demonstrated by simultaneously polymerising and crosslinking aqueous NIPAm monomer solutions. The volume-change kinetic studies show that EB crosslinked hydrogels swell/deswell to attain equilibrium at much faster rate compared to conventionally crosslinked hydrogels. The fast-response has been attributed to formation of inhomogeneously crosslinked network under EB irradiation conditions. (author)

1998-01-01

224

Rapid response and wide range neutronic power measuring systems for fast pulsed reactors  

International Nuclear Information System (INIS)

This paper summarizes our investigation on design principles of the rapid, stable and wide range neutronic power measuring system for fast pulsed reactors. The picoammeter, the logarithmic amplifier, the reactivity meter and the neutron current chamber are the items of investigation. In order to get a rapid response, the method of compensation for the stray capacitance of the feedback circuits and the capacitance of signal cables is applied to the picoammeter, the logarithmic amplifier and the reactivity meter with consideration for the stability margin of a whole detecting system. The response of an ionization current chamber and the method for compensating the ion component of the chamber output to get optimum responses high pass filters are investigated. Statistical fluctuations of the current chamber output are also considered in those works. The optimum thickness of the surrounding moderator of the neutron detector is also discussed from the viewpoint of the pulse shape deformation and the neutron sensitivity increase. The experimental results are reported, which were observed in the pulse operations of the one shot fast pulsed reactor ''YAYOI'' and the one shot TRIGA ''NSRR'' with the measuring systems using those principles. (auth.)

1976-01-19

225

Spectral Effects of Fast Response Cross Kerr Non-Linearity on Quantum Gate  

CERN Document Server

According to idealized models, a strong Kerr non-linearity may be used to build optical quantum gates for optical quantum information processing by inducing conditional phase shifts on quantum states. Recently, Shapiro (PRA 73, 062305 (2006)) argued that for a Kerr medium with non-instantaneous but fast response, essentially no phase shift is induced on two-single-photon input states, and thus a quantum gate build from such a medium cannot work. Here we show that a fast response Kerr medium induces some but very little phase shifts on a two-single-photon input state, and it is insufficient for high fidelity quantum computation. We point out that this is caused by the medium imparting spectral entanglement to the input photons. We further show that a way to circumvent this problem and achieve a high fidelity gate, is to engineer the dispersion properties of the medium to give a dominant spectral effect over the non-instantaneous response, in addition to satisfying a phase matching condition.

Leung, P M; Munro, William J; Nemoto, Kae

2008-01-01

226

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

227

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

International Nuclear Information System (INIS)

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

2010-11-01

228

Parallelized fast multipole BEM based on the convolution quadrature method for 3-D wave propagation problems in time-domain  

International Nuclear Information System (INIS)

This paper presents a new time-domain boundary element method (BEM) using a convolution quadrature method (CQM) and a fast multipole method (FMM) in 3-D scalar wave propagation. In general, the use of direct time-domain BEM sometimes causes the numerical instability of time-stepping solutions and needs much computational time and memory. To overcome these difficulties, in this paper, the convolution quadrature method developed by Lubich is applied to establish the stability behavior of the time-stepping scheme. Moreover, the fast multipole method and parallelization techniques are adapted to improve the computational efficiency for large size problems. The formulation and numerical implementation of the new boundary element method, and the basic formulas for the fast multipole method such as the multipole expansion, the local expansion, and the translation relations of them in the fast multipole algorithm are presented. The accuracy, the computational efficiency and the applicability are checked by solving 3-D large scale wave scattering problems.

2010-06-01

229

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

International Nuclear Information System (INIS)

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.

2009-06-01

230

Fast Tracker: a hardware real time track finder for the ATLAS trigger system  

Science.gov (United States)

The Fast Tracker (FTK) is an integral part of the trigger upgrade program of the ATLAS detector at the Large Hadron Collider (LHC). As the LHC luminosity approaches its design level of 1034 cm?2s?1, the combinatorial problem posed by charged particle tracking becomes increasingly difficult due to the swelling of multiple interactions per bunch crossing. The FTK is a highly-parallel hardware system intended to provide high-quality tracks with transverse momentum above 1 GeV in real time for online trigger system. The FTK system's design, based on a mixture of advanced technologies, and the expected physics performance will be presented.

Kimura, N.

2014-04-01

231

Fast X-ray tomography for time-resolved measurements of flow velocities  

International Nuclear Information System (INIS)

A given fast X-ray tomograph with two parallel measuring planes is used for spatially resolved measurements of flow velocities by design. Now it is to be extended to time-resolved measurements avoiding any additional technical effort. But the spacing between the planes is too big. Thus, an additional indirect measuring plane is defined utilizing radiation which propagates between the regular planes during the tomographic scan. This indirect plane is close enough to one of the regular planes. A practical example illustrates the mode of measurement using the new method. (orig.)

2013-01-01

232

A CFD-based wind solver for a fast response transport and dispersion model  

Energy Technology Data Exchange (ETDEWEB)

In many cities, ambient air quality is deteriorating leading to concerns about the health of city inhabitants. In urban areas with narrow streets surrounded by clusters of tall buildings, called street canyons, air pollution from traffic emissions and other sources is difficult to disperse and may accumulate resulting in high pollutant concentrations. For various situations, including the evacuation of populated areas in the event of an accidental or deliberate release of chemical, biological and radiological agents, it is important that models should be developed that produce urban flow fields quickly. For these reasons it has become important to predict the flow field in urban street canyons. Various computational techniques have been used to calculate these flow fields, but these techniques are often computationally intensive. Most fast response models currently in use are at a disadvantage in these cases as they are unable to correlate highly heterogeneous urban structures with the diagnostic parameterizations on which they are based. In this paper, a fast and reasonably accurate computational fluid dynamics (CFD) technique that solves the Navier-Stokes equations for complex urban areas has been developed called QUIC-CFD (Q-CFD). This technique represents an intermediate balance between fast (on the order of minutes for a several block problem) and reasonably accurate solutions. The paper details the solution procedure and validates this model for various simple and complex urban geometries.

Gowardhan, Akshay A [Los Alamos National Laboratory; Brown, Michael J [Los Alamos National Laboratory; Pardyjak, Eric R [UNIV OF UTAH; Senocak, Inanc [BOISE STATE UNIV

2010-01-01

233

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.

Nowak S.

2012-09-01

234

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

2009-09-01

235

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

CERN Document Server

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

236

Concatenated Space-Time Block Coding with Asymmetric MPSK TCM for Fast Fading Channels  

Directory of Open Access Journals (Sweden)

Full Text Available The field of concatenated space-time block coding (inner with trellis coded modulation (outer has recently attracted interest as a means of jointly considering the error correction coding gain and diversity gain possible without bandwidth expansion and power expansion over fading channels. In this research, a concatenated Space-Time Block Coding (STBCwith asymmetric MPSK TCM scheme, based on the design criteria for constructing concatenated space-time block coding with TCM for fast Rayleigh fading channels, is presented by introducing the new optimal signal point assignment. Using parameter comparison and simulation results, the proposed concatenated STBC with asymmetric MPSK TCM is shown to have better coding gain than traditional concatenated STBC with TCM under the same spectral efficiency, decoding complexity.

Ao Ju

2008-01-01

237

Fast real-time PCR for the detection of crustacean allergen in foods.  

Science.gov (United States)

Crustaceans are one of the most common allergens causing severe food reaction. These food allergens are a health problem, and they have become very important; there are various regulations that establish that labeling must be present regarding these allergens to warn consumers. In the present work a fast real-time PCR, by a LNA probe, was developed. This allows the detection of crustaceans in all kinds of products, including processed products in which very aggressive treatments of temperature and pressure during the manufacturing process are used. This methodology provides greater sensitivity and specificity and reduces the analysis time of real-time PCR to 40 min. This methodology was further validated by means of simulating products likely to contain this allergen. For this, products present on the market were spiked with crustacean cooking water. The assay is a potential tool in issues related to the labeling of products and food security to protect the allergic consumer. PMID:22339490

Herrero, Beatriz; Vieites, Juan M; Espiñeira, Montserrat

2012-02-29

238

The ITER Fast Plant System Controller ATCA prototype Real-Time Software Architecture  

International Nuclear Information System (INIS)

Highlights: ? High performance ATCA systems for fast control and data acquisition. ? IEEE1588 timing system and synchronization. ? Plasma control algorithms. ? Real-time control software frameworks. ? Targeted for nuclear fusion experiments with long duration discharges. -- Abstract: IPFN is developing a prototype Fast Plant System Controller (FPSC) based in ATCA embedded technologies dedicated to ITER CODAC data acquisition and control tasks in the sub-millisecond range. The main goal is to demonstrate the usability of the ATCA standard and its enhanced specifications for the high speed, very high density parallel data acquisition needs of the most demanding ITER tokamak plasma Instrumentation and Control (I and C) systems. This effort included the in-house development of a new family of high performance ATCA I/O and timing boards. The standard ITER software system CODAC Core System (CCS) v3.1, with the control based in the EPICS system does not cover yet the real-time requirements fulfilled by this hardware, so a new set of software components was developed for this specific platform, attempting to integrate and leverage the new features in CSS, for example the Multithreaded Application Real Time executor (MARTe) software framework, the new Data Archiving Network (DAN) solution, an ATCA IEEE-1588-2008 timing interface, and the Intelligent Platform Management Interface (IPMI) for system monitoring and remote management. This paper presents the overall software architecture for the ATCA FPSC, as well a discussion on the ITER constrains and design choices and finally a detailed description of the software components already developed

2013-10-01

239

The ITER Fast Plant System Controller ATCA prototype Real-Time Software Architecture  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? High performance ATCA systems for fast control and data acquisition. ? IEEE1588 timing system and synchronization. ? Plasma control algorithms. ? Real-time control software frameworks. ? Targeted for nuclear fusion experiments with long duration discharges. -- Abstract: IPFN is developing a prototype Fast Plant System Controller (FPSC) based in ATCA embedded technologies dedicated to ITER CODAC data acquisition and control tasks in the sub-millisecond range. The main goal is to demonstrate the usability of the ATCA standard and its enhanced specifications for the high speed, very high density parallel data acquisition needs of the most demanding ITER tokamak plasma Instrumentation and Control (I and C) systems. This effort included the in-house development of a new family of high performance ATCA I/O and timing boards. The standard ITER software system CODAC Core System (CCS) v3.1, with the control based in the EPICS system does not cover yet the real-time requirements fulfilled by this hardware, so a new set of software components was developed for this specific platform, attempting to integrate and leverage the new features in CSS, for example the Multithreaded Application Real Time executor (MARTe) software framework, the new Data Archiving Network (DAN) solution, an ATCA IEEE-1588-2008 timing interface, and the Intelligent Platform Management Interface (IPMI) for system monitoring and remote management. This paper presents the overall software architecture for the ATCA FPSC, as well a discussion on the ITER constrains and design choices and finally a detailed description of the software components already developed.

Carvalho, B.B., E-mail: bernardo@ipfn.ist.utl.pt [Associacao EURATOM/IST Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, P-1049-001 Lisboa (Portugal); Santos, B.; Carvalho, P.F.; Neto, A. [Associacao EURATOM/IST Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, P-1049-001 Lisboa (Portugal); Boncagni, L. [Associazione Euratom-ENEA sulla Fusione, Frascati Research Centre, Division of Fusion Physics, Frascati, Rome (Italy); Batista, A.J.N.; Correia, M.; Sousa, J.; Gonçalves, B. [Associacao EURATOM/IST Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, P-1049-001 Lisboa (Portugal)

2013-10-15

240

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

2012-09-01

 
 
 
 
241

Physiotherapy Exercise After Fast-Track Total Hip and Knee Arthroplasty: Time for Reconsideration?  

DEFF Research Database (Denmark)

Bandholm T, Kehlet H. Physiotherapy exercise after fast-track total hip and knee arthroplasty: time for reconsideration? Major surgery, including total hip arthroplasty (THA) and total knee arthroplasty (TKA), is followed by a convalescence period, during which the loss of muscle strength and function is considerable, especially early after surgery. In recent years, a combination of unimodal evidence-based perioperative care components has been demonstrated to enhance recovery, with decreased need for hospitalization, convalescence, and risk of medical complications after major surgery-the fast-track methodology or enhanced recovery programs. It is the nature of this methodology to systematically and scientifically optimize all perioperative care components, with the overall goal of enhancing recovery. This is also the case for the care component "physiotherapy exercise" after THA and TKA. The 2 latest meta-analyses on the effectiveness of physiotherapy exercise after THA and TKA generally conclude that physiotherapy exercise after THA and TKA either does not work or is not very effective. The reason for this may be that the "pill" of physiotherapy exercise typically offered after THA and TKA does not contain the right active ingredients (too little intensity) or is offered at the wrong time (too late after surgery). We propose changing the focus to earlier initiated and more intensive physiotherapy exercise after THA and TKA (fast-track physiotherapy exercise), to reduce the early loss of muscle strength and function after surgery. Ideally, the physiotherapy exercise interventions after THA and TKA should be simple, using few and well-chosen exercises that are described in detail, adhering to basic exercise physiology principles, if possible.

Bandholm, Thomas; Kehlet, Henrik

2012-01-01

242

Design and evaluation of a device for fast multispectral time-resolved fluorescence spectroscopy and imaging  

Science.gov (United States)

The application of time-resolved fluorescence spectroscopy (TRFS) to in vivo tissue diagnosis requires a method for fast acquisition of fluorescence decay profiles in multiple spectral bands. This study focusses on development of a clinically compatible fiber-optic based multispectral TRFS (ms-TRFS) system together with validation of its accuracy and precision for fluorescence lifetime measurements. It also presents the expansion of this technique into an imaging spectroscopy method. A tandem array of dichroic beamsplitters and filters was used to record TRFS decay profiles at four distinct spectral bands where biological tissue typically presents fluorescence emission maxima, namely, 390, 452, 542, and 629 nm. Each emission channel was temporally separated by using transmission delays through 200 ?m diameter multimode optical fibers of 1, 10, 19, and 28 m lengths. A Laguerre-expansion deconvolution algorithm was used to compensate for modal dispersion inherent to large diameter optical fibers and the finite bandwidth of detectors and digitizers. The system was found to be highly efficient and fast requiring a few nano-Joule of laser pulse energy and tissue autofluorescent components. Organic and biological chromophores with lifetimes that spanned a 0.8-7 ns range were used for system validation, and the measured lifetimes from the organic fluorophores deviated by less than 10% from values reported in the literature. Multi-spectral lifetime images of organic dye solutions contained in glass capillary tubes were recorded by raster scanning the single fiber probe in a 2D plane to validate the system as an imaging tool. The lifetime measurement variability was measured indicating that the system provides reproducible results with a standard deviation smaller than 50 ps. The ms-TRFS is a compact apparatus that makes possible the fast, accurate, and precise multispectral time-resolved fluorescence lifetime measurements of low quantum efficiency sub-nanosecond fluorophores.

Yankelevich, Diego R.; Ma, Dinglong; Liu, Jing; Sun, Yang; Sun, Yinghua; Bec, Julien; Elson, Daniel S.; Marcu, Laura

2014-03-01

243

The usefulness of time-dependent reactor accident consequence modelling for emergency response planning  

International Nuclear Information System (INIS)

After major releases of radionuclides into the atmosphere fast reaction of authorities will be necessary to inform the public of potential consequences and to consider and optimize mitigating actions. These activities require availability of well designed computer models, adequate and fast measurements and prior training of responsible persons. The quantitative assessment models should be capable of taking into account of actual atmospheric dispersion conditions, actual deposition situation (dry, rain, snow, fog), seasonal status of the agriculture, food processing and distribution pathways, etc. In this paper the usefulness of such models will be discussed, their limitations, the relative importance of exposure pathways and a selection of important methods to decrease the activity in food products after an accident. Real-time reactor accident consequence models should be considered as a condition sine qua non for responsible use of nuclear power for electricity production

1989-01-01

244

In-situ response time testing of force-balance pressure transmitters in nuclear power plants  

International Nuclear Information System (INIS)

This paper reports on recommendations for response time testing of safety system pressure transmitters in nuclear power plants that are found in Regulatory Guide 1.118 and requirements are defined in plant technical specifications. The conventional testing method involves simultaneously applying a pressure ramp signal to the process transmitter and to a fast-response reference transmitter. The time delay between the response of the two transmitters, when they obtain a predetermined value, is called the process transmitter response time. This method is referred to as the ramp test. Although the ramp test is an accepted method, large variations in its results are sometimes encountered because of empirical difficulties associated with the test. This test requires access to each transmitter, and it must be performed inside the containment during shutdown. The in-situ test is accomplished by interrupting the power to the transmitter for a few seconds. It is referred to as the Power Interrupt (PI) test, and it can be conducted while the plant is operating. The test includes the entire electromechanical system and the response time is obtained by analyzing the transient response following the restoration of power to the transmitter. Response times obtained from the PI test and the ramp test are in good agreement and usually differ by less than 50 ms

1989-05-15

245

Highly responsive Y-Ba-Cu-O thin film THz detectors with picosecond time resolution  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High-temperature superconducting YBa2Cu3O7-d (YBCO) thin-film detectors with improved responsivities were developed for fast time-domain measurements in the THz frequency range. YBCO thin films of 30 nm thickness were patterned to micro- and nanobridges and embedded into planar log-spiral THz antennas. The YBCO thin-film detectors were characterized with continuous wave radiation at 0.65 THz. Responsivity values as high as 710 V/W were found for the YBCO nanobridges. Pulsed ...

Thoma, P.; Raasch, J.; Scheuring, A.; Hofherr, M.; Ilin, K.; Wu?nsch, S.; Semenov, A.; Hu?bers, H. -w; Judin, V.; Mu?ller, A. -s; Smale, N.; Ha?nisch, J.; Holzapfel, B.; Siegel, M.

2012-01-01

246

Development of a generalized model to analyze time and frequency responses for SAW sensors  

Science.gov (United States)

Most of the research on applications of wireless surface acoustic wave (SAW) sensors has focused on the fabrication process. No detailed theoretical models have been developed to illustrate the time and frequency domain characteristics of SAW devices. In this paper, the generalized model of the wireless SAW sensor is established by using the coupling-of-modes (COM) model together with the wave equations. The generalized model is developed to analyze four main applications, which include tag-ID design, the bio-reaction process, tension measurement and temperature sensing. Both the time response and frequency response are investigated to determine the appropriate signal processing for different applications. It is found that for the time response using the inverse fast Fourier transform (IFFT) is more suitable for tag-ID and the phase shift is better for bio-sensing, tension and temperature sensing. Furthermore, the developed model can be utilized to expedite the design process for wireless sensing devices.

Tsai, Meng-Shiun; Jeng, Jie-Ting

2011-02-01

247

Development of a generalized model to analyze time and frequency responses for SAW sensors  

International Nuclear Information System (INIS)

Most of the research on applications of wireless surface acoustic wave (SAW) sensors has focused on the fabrication process. No detailed theoretical models have been developed to illustrate the time and frequency domain characteristics of SAW devices. In this paper, the generalized model of the wireless SAW sensor is established by using the coupling-of-modes (COM) model together with the wave equations. The generalized model is developed to analyze four main applications, which include tag-ID design, the bio-reaction process, tension measurement and temperature sensing. Both the time response and frequency response are investigated to determine the appropriate signal processing for different applications. It is found that for the time response using the inverse fast Fourier transform (IFFT) is more suitable for tag-ID and the phase shift is better for bio-sensing, tension and temperature sensing. Furthermore, the developed model can be utilized to expedite the design process for wireless sensing devices

2011-02-01

248

A fast and accurate 3-D prestack Kirchhoff summation time migration  

Energy Technology Data Exchange (ETDEWEB)

Prestack migration is more accurate than stack plus poststack migration, and it is not difficult to find the differences between them; these differences tend to increase with increasing offset. Typically, 3-D data sets lack near offsets, hence prestack migration is more important for 3-D data than for 2-D data. However, 3-D stack migration usually is expensive, especially for data sets with high frequency content. It may not be possible to reduce the cost dramatically when lateral velocity gradients are large and 3-D prestack depth migration is necessary. However, for many 3-D seismic data sets, lateral velocity changes are relatively small. In such cases, the Kirchhoff prestack time migration can be fast and accurate, even if data show high frequency content. The approximations made in usual Kirchhoff time migration compared to real time migration are summarized. They are that a 1-D velocity profile at the source-receiver midpoint is used to approximate real velocity distributions in which rays pass from the source to the receiver; a simple formula based on RMS velocity is used to determine travel time from the source-receiver point to each image point instead of ray tracing or wave propagation; and amplitude adjustments assume that the amplitude is proportional to the cosine of the angle between the direction of wave propagation and the vertical coordinate divided by the distance from the source to the wavefront for 3-D, and that the amplitude is proportional to the cosine and the square root of the distance for 2-D. Prestack migration is more accurate than poststack migration especially for 3-D sets. If lateral velocity changes are relatively small, the fast and accurate Kirchhoff summation time migration presented herein can produce good results. 1 ref.

Wu Wen-Jing [Geo-X Systems Ltd., Calgary, AB (Canada)

1999-11-01

249

A Correlation-based Timing Calibration and Diagnostic Technique for Fast Digitizing ASICs  

Science.gov (United States)

A general procedure for precision timing calibration of waveform digitizing systems is presented. Application speci?c integrated circuits (ASICs) implementing this functionality are increasingly used in high-energy physics as replacements for stand-alone time-to-digital and analog-to-digital modules. However, process variations cause such ASICs to have irregularly spaced timing intervals between samples, so careful calibration is required to improve the timing resolution of such systems. The procedure presented here exploits correlations between nearby samples of a sine wave of known frequency to obtain the time difference between them. As only the correlations are used, the procedure can be performed without knowledge of the phase of the input signal, and converges with smaller data samples than other common techniques. It also serves as a valuable diagnostic tool, allowing a fast, visual, qualitative check of gain mismatches between sampling cells and other ADC artifacts. Work is continuing to extend the procedure to ?t for timing intervals in the face of such non-idealities. We present both the algorithm and example calibration results from a commercial oscilloscope and the PSEC-3 ASIC. For the latter, we have also applied the calibration to improve timing resolution in the readout of a prototype microchannel plate photomultiplier tube with a stripline anode con?guration.

Nishimura, Kurtis; Romero-Wolf, Andrés; For the Large Area Picosecond Photodetector Collaboration [1

250

Time and space resolved interferometry for laser-generated fast electron measurements  

Energy Technology Data Exchange (ETDEWEB)

A technique developed to measure in time and space the dynamics of the electron populations resulting from the irradiation of thin solids by ultraintense lasers is presented. It is a phase reflectometry technique that uses an optical probe beam reflecting off the target rear surface. The phase of the probe beam is sensitive to both laser-produced fast electrons of low-density streaming into vacuum and warm solid density electrons that are heated by the fast electrons. A time and space resolved interferometer allows to recover the phase of the probe beam sampling the target. The entire diagnostic is computationally modeled by calculating the probe beam phase when propagating through plasma density profiles originating from numerical calculations of plasma expansion. Matching the modeling to the experimental measurements allows retrieving the initial electron density and temperature of both populations locally at the target surface with very high temporal and spatial resolution ({approx}4 ps,6 {mu}m). Limitations and approximations of the diagnostic are discussed and analyzed.

Antici, P. [Istituto Nazionale di Fisica Nucleare, Via E. Fermi, Frascati 40-00044 (Italy); ILE-Ecole Polytechnique-CNRS-ENSTA-Iogs-UP Sud, Batterie de l' Yvette, Palaiseau 91761 (France) and Dipartimento di Scienze di Base e Applicate per l' Ingegneria, Sapienza-Universita di Roma, Via A. Scarpa 14, Roma 00161 (Italy); LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, Palaiseau 91128 (France); Chen, S. N. [Livermore National Laboratory, L-209, P.O. Box 808, Livermore, California 94550 (United States); Gremillet, L. [CEA, DAM, DIF, Arpajon, F-91297 (France); Grismayer, T.; Mora, P. [Centre de Physique Theorique, Ecole Polytechnique, CNRS, Palaiseau 91128 (France); Audebert, P.; Fuchs, J. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, Palaiseau 91128 (France)

2010-11-15

251

Time and space resolved interferometry for laser-generated fast electron measurements  

International Nuclear Information System (INIS)

A technique developed to measure in time and space the dynamics of the electron populations resulting from the irradiation of thin solids by ultraintense lasers is presented. It is a phase reflectometry technique that uses an optical probe beam reflecting off the target rear surface. The phase of the probe beam is sensitive to both laser-produced fast electrons of low-density streaming into vacuum and warm solid density electrons that are heated by the fast electrons. A time and space resolved interferometer allows to recover the phase of the probe beam sampling the target. The entire diagnostic is computationally modeled by calculating the probe beam phase when propagating through plasma density profiles originating from numerical calculations of plasma expansion. Matching the modeling to the experimental measurements allows retrieving the initial electron density and temperature of both populations locally at the target surface with very high temporal and spatial resolution (?4 ps,6 ?m). Limitations and approximations of the diagnostic are discussed and analyzed.

2010-11-01

252

Performance evaluation of response time in ATM LANs  

Energy Technology Data Exchange (ETDEWEB)

This contribution compares the response-time performance of ATM LANs using ABR EFCI, UBR FIFO, and UBR with per VC queuing switches. Our study is based on experimental as well as simulation results. We found that, with or without congestion, UBR switches with per VC queuing provide the best response times.

Chen, H.; Brandt, J.

1995-12-11

253

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

254

A Statistical Approach to Response-Time Analysis of Complex Real-Time Embedded Systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents RapidRT, a novel statistical approach to Worst-Case Response-Time (WCRT) analysis targeting complex embedded real-time systems. The proposed algorithm combines Extreme Value Theory (EVT) and other statistical methods in order to produce a probabilistic WCRT estimate. This estimate is calculated using response time data from either Monte Carlo simulations of a detailed model of the system, or from response-time measurements of the real system. The method could be considered...

Lu, Yue; Nolte, Thomas; Kraft, Johan; Norstro?m, Christer

2010-01-01

255

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

CERN Document Server

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

256

Function parametrization applied to capacitive pressure sensor response time  

International Nuclear Information System (INIS)

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)

1995-06-19

257

Equilibrium free energies from fast-switching trajectories with large time steps  

CERN Document Server

Jarzynski's identity for the free energy difference between two equilibrium states can be viewed as a special case of a more general procedure based on phase space mappings. Solving a system's equation of motion by approximate means generates a mapping that is perfectly valid for this purpose, regardless of how closely the solution mimics true time evolution. We exploit this fact, using crudely dynamical trajectories to compute free energy differences that are in principle exact. Numerical simulations show that Newton's equation can be discretized to low order over very large time steps (limited only by the computer's ability to represent resulting values of dynamical variables) without sacrificing thermodynamic accuracy. For computing the reversible work required to move a particle through a dense liquid, these calculations are more efficient than conventional fast switching simulations by more than an order of magnitude. We also explore consequences of the phase space mapping perspective for systems at equi...

Lechner, W; Dellago, C; Geissler, Phillip L; Lechner, Wolfgang; Oberhofer, Harald; Dellago, Christoph; Geissler, Phillip L.

2005-01-01

258

Comparative study of fast MR imaging: quantitative analysis on image quality and efficiency among various time frames and contrast behaviors.  

Science.gov (United States)

The purpose of this study is to quantitatively compare the image quality and efficiency provided by widely available fast MR imaging pulse sequences. A composite phantom with various T1 and T2 values and subjected to periodic motion was imaged at 1.5 T. The fast MRI sequences evaluated included fast spin-echo (FSE), single shot fast spin-echo (SSFSE), echo-planar imaging (EPI), multi-slice gradient recalled (MPGR), fast MPGR (FMPGR), and fast multi-slice spoiled gradient echo (FMPSPGR). T1-weighted (T1WI), T2-weighted (T2WI), proton-density-weighted (PDWI), and T2*-weighted (T2*WI) images were evaluated in breath-hold and non-breath-hold time frames. Analysis included measurement of image signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), nonuniformity, ghosting ratio, SNR per unit time and CNR per unit time. Among fast T2WI sequences, FSE with breath-hold time frame resulted in the highest image quality and in superior SNR and CNR efficiency by a factor of 5 or 6 as compared with conventional spin echo sequence. Among fast T1WI sequences, FMPGR and FMPSPGR both with non-breath-hold time frame produced the highest image quality and SNR and CNR efficiency by a factor of greater than 5 as compared with conventional spin echo. Among fast PDWI and T2*WI sequences, FSE produced the highest SNR and CNR, and was maximally efficient with a factors of greater than 6 as compared with conventional spin echo. PMID:12361794

Li, Tao; Mirowitz, Scott A

2002-07-01

259

Improving the Average Response Time in Collective I/O  

Energy Technology Data Exchange (ETDEWEB)

In collective I/O, MPI processes exchange requests so that the rearranged requests can result in the shortest file system access time. Scheduling the exchange sequence determines the response time of participating processes. Existing implementations that simply follow the increasing order of file ofsets do not necessary produce the best performance. To minimize the average response time, we propose three scheduling algorithms that consider the number of processes per file stripe and the number of accesses per process. Our experimental results demonstrate improvements of up to 50% in the average response time using two synthetic benchmarks and a high-resolution climate application.

Jin, Chen; Sehrish, Saba; Liao, Wei-keng; Choudhary, Alok; Schuchardt, Karen L.

2011-09-21

260

Fast response detection of H2S by CuO-doped SnO2 films prepared by electrodeposition and oxidization at low temperature  

International Nuclear Information System (INIS)

Highlights: ? The low temperature and fast response films for H2S gas detection. ? Preparation by an electrodeposition and oxidization method. ? Improve the response and recovery properties of gas detection. - Abstract: Fast response detection of H2S by CuO-doped SnO2 films prepared was prepared by a simple two-step process: electrodeposition from aqueous solutions of SnCl2 and CuCl2, and oxidization at 600 deg. C. The phase constitution and morphology of the CuO-doped SnO2 films were characterized by X-ray diffraction and scanning electron microscopy. In all cases, a polycrystalline porous film of SnO2 was the product, with the CuO deposited on the individual SnO2 particles. Two types of CuO-doped SnO2 films with different microstructures were obtained via control of oxidation time: nanosized CuO dotted island doped SnO2 and ultra-uniform, porous, and thin CuO film coated SnO2. The sensor response of the CuO doped SnO2 films to H2S gas at 50-300 ppm was investigated within the temperature range of 25-125 deg. C. Both of the CuO-doped SnO2 films show fast response and recovery properties. The response time of the ultra-uniform, porous, and thin CuO coated SnO2 to H2S gas at 50 ppm was 34 s at 100 deg. C, and its corresponding recovery time was about 1/3 of the response time.

2011-11-01

 
 
 
 
261

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

2003-04-01

262

A fast neutron time-of-flight and scattering angle measuring system with online flight time correction  

International Nuclear Information System (INIS)

The paper describes a microprocessor controlled VMEbus system for neutron scattering experiments at the new Berlin Experimental Reactor BER 2. The system measures the distribution of neutron time-of-flight by spatially distributed detectors (400 single detectors or a multi-detector array with 4,096 elements) and generates a two-dimensional histogram with 4 K time channels and 4 K detector position channels in a 32 MB memory. Several outstanding features are described in detail: (1) An online time-of-flight correction compensates different lengths of neutron flight paths, in order to obtain undistorted spectra if, e.g., a planar detector array is used. (2) The system is designed for very fast processing of the events detected, to allow high neutron counting rates of up to 500,000 neutrons/s in average and up to 2 x 106 neutrons/s as peak rate. (3) To provide a maximum of flexibility for the user, the operation of the system is based on pre-calculated tables and parameters which allow a wide variety of system configurations to satisfy very different requirements of the experiments

1994-02-01

263

Model for Predicting End User Web Page Response Time  

CERN Document Server

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

264

Analytical study of the pressure sensor response times  

International Nuclear Information System (INIS)

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

265

Synchronous timing of multi-energy fast beam extraction during a single AGS cycle  

International Nuclear Information System (INIS)

Synchronous triggering of fast beams is required because the field of Kicker Magnets must rise within the open space between one beam bunch and the next. Within the Brookhaven AGS, Fast Extracted Beam (FEB) triggering combines nominal timing, based on beam energy with bunch-to-bunch synchronization, based on the accelerating rf waveform. During beam acceleration, a single bunch is extracted at 22 GeV/c and within the same AGS cycle, the remaining eleven bunches are extracted at 28.4 GeV/c. When the single bunch is extracted, a ''hole'', which is left in the remaining circulating beam, can appear in random locations within the second extraction during successive AGS cycles. To overcome this problem, a synchronous rf/12 counting scheme and logic circuitry are used to keep track of the bunch positions relative to each other, and to place the ''hole'' in any desired location within the second extraction. The rf/12 signal is used also to synchronize experimenters triggers

1985-10-01

266

Signal and Noise Analysis in TRION -Time-Resolved Integrative Optical Fast Neutron Detector  

CERN Multimedia

TRION is a sub-mm spatial resolution fast neutron imaging detector, which employs an integrative optical time-of-flight technique. The detector was developed for fast neutron resonance radiography, a method capable of detecting a broad range of conventional and improvised explosives. In this study we have analyzed in detail, using Monte-Carlo calculations and experimentally determined parameters, all the processes that influence the signal and noise in the TRION detector. In contrast to event-counting detectors where the signal-to-noise ratio is dependent only on the number of detected events (quantum noise), in an energy-integrating detector additional factors, such as the fluctuations in imparted energy, number of photoelectrons, system gain and other factors will contribute to the noise. The excess noise factor (over the quantum noise) due to these processes was 4.3, 2.7, 2.1, 1.9 and 1.9 for incident neutron energies of 2, 4, 7.5, 10 and 14 MeV, respectively. It is shown that, even under ideal light colle...

Vartsky, D; Mor, I; Goldberg, M B; Bar, D; Dangendorf, V

2009-01-01

267

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

268

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

1999-06-21

269

Physiotherapy exercise after fast-track total hip and knee arthroplasty: time for reconsideration?  

Science.gov (United States)

Major surgery, including total hip arthroplasty (THA) and total knee arthroplasty (TKA), is followed by a convalescence period, during which the loss of muscle strength and function is considerable, especially early after surgery. In recent years, a combination of unimodal evidence-based perioperative care components has been demonstrated to enhance recovery, with decreased need for hospitalization, convalescence, and risk of medical complications after major surgery-the fast-track methodology or enhanced recovery programs. It is the nature of this methodology to systematically and scientifically optimize all perioperative care components, with the overall goal of enhancing recovery. This is also the case for the care component "physiotherapy exercise" after THA and TKA. The 2 latest meta-analyses on the effectiveness of physiotherapy exercise after THA and TKA generally conclude that physiotherapy exercise after THA and TKA either does not work or is not very effective. The reason for this may be that the "pill" of physiotherapy exercise typically offered after THA and TKA does not contain the right active ingredients (too little intensity) or is offered at the wrong time (too late after surgery). We propose changing the focus to earlier initiated and more intensive physiotherapy exercise after THA and TKA (fast-track physiotherapy exercise), to reduce the early loss of muscle strength and function after surgery. Ideally, the physiotherapy exercise interventions after THA and TKA should be simple, using few and well-chosen exercises that are described in detail, adhering to basic exercise physiology principles, if possible. PMID:22494947

Bandholm, Thomas; Kehlet, Henrik

2012-07-01

270

Performance of Downlink DSTBC-WCDMA in Fast-Varying Time-Dispersive Channels  

Science.gov (United States)

This paper presents the performance of DSTBC when applied on the downlink transmission of WCDMA cellular systems in fast-varying time-dispersive channels. First, three DSTBC-WCDMA receiver architectures are proposed and they are: (1) the DSTBC Rake receiver for combined-code (D-Rake-C), (2) the DSTBC deterministic receiver for combined-code (D-Det-C), and (3) the DSTBC deterministic de-prefix receiver for combined-code (D-Det-DP-C). Detection can be divided into a correlator that combines descrambling and despreading, and a DSTBC decoder. The correlator is designed to perform signal separation of the multipath-multiuser signal via least-square (LS) estimation. To enable the correlator to perform signal separation at every block period, the long combined spreading and scrambling codes are divided into shorter codes. Then, the proposed receivers are theoretically analyzed in time-dispersive channels and multiple-user environment using the moment generating function (MGF) of fading distributions. For analyzing interference tolerance, the standard Gaussian approximation is employed. Finally, simulations are performed. Theoretical performance well matches simulated results. Among the three receivers, the D-Det-DP-C receiver has the best performance in time-dispersive channels with a maximum excess delay of 4 chips and a maximum Doppler frequency of 250Hz. Results also show minimal performance degradation for fast fading channels with a maximum Doppler frequency of 1200Hz. The best performance is obtained when the receiver has the information on the maximum excess delay and all users' spreading codes.

Umali, Edwin M.; Marciano, Joel Joseph S., Jr.; Yamao, Yasushi

271

Comparison of measurement data at the impeller exit of a centrifugal compressor measured with both pneumatic and fast-response probes  

Energy Technology Data Exchange (ETDEWEB)

The main goal of these investigations was the refined measurement of unsteady high speed flow in a centrifugal compressor using the advanced FRAP{reg_sign} fast-response aerodynamic probe system. The present contribution focuses on the impeller exit region and shows critical comparisons between fast-response (time-resolving) and conventional pneumatic probe measurement results. Three probes of identical geometry (one fast and two pneumatic) were used to perform wall-to-wall traverses close to impeller exit. The data shown refer to a single running condition near the best point of the stage. The mass flow obtained from different probe measurements and from the standard orifice measurement were compared. Stage work obtained from temperature rise measured with a FRAP{reg_sign} probe and from impeller outlet velocity vectors fields by using Euler`s turbine equation are presented. The comparison in terms of velocity magnitude and angle distribution is quite satisfactory, indicating the superior DC measurement capabilities of the fast-response probe system.

Roduner, C.; Koeppel, P.; Kupferschmied, P.; Gyarmathy, G. [ETH-Swiss Federal Inst. of Tech., Zurich (Switzerland)

1999-07-01

272

Fast-response magnet coil system for controlling plasma equilibrium in a tokamak with a strong magnetic field  

International Nuclear Information System (INIS)

Two special fast-control coils are used to provide stability of a plasma filament in a horizontal plane of a tokamak with a strong magnetic field. According to the fast-response conditions satisfying the control system, power of the supply system for these coils is to constitute 35 MW (U=2.5 kV, I=14 kA). A basic circuit of the supply system with a capacitor is given, the circuit consists of a capacitor bank with a rectifier providing for a preliminary chage of a capacitor bank, thyristor switches, a shut-down system, circuit breakers, valve devices. A basic circuit of supply system for plasma equilibrium coil built on the base of fast-response and reliability priciples is presented. Fast voltage removal is provided by shorting out a c

1984-06-20

273

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

274

Metabolic response to a glucagon challenge varies with adiposity and life-history stage in fasting northern elephant seals.  

Science.gov (United States)

Metabolic adaptations for extended fasting in wildlife prioritize beta-oxidation of lipids and reduced glucose utilization to support energy metabolism. The pancreatic hormone glucagon plays key roles in regulating glycemia and lipid metabolism during fasting in model species but its function in wildlife species adapted for extended fasting is not well understood. Northern elephant seals (NES) undergo natural fasts of 1-3months while under constraints of high nutrient demands including lactation and development. We performed a glucagon challenge on lactating, molting and developing NES, early and late in their natural fasts, to examine the impact of this important regulatory hormone on metabolism. Glucagon caused increases in plasma glucose, insulin, fatty acids, ketones and urea, but the magnitude of these effects varied widely with adiposity and life-history stage. The strong impact of adiposity on glucose and insulin responses suggest a potential role for adipose derived factors in regulating hepatic metabolism and pancreatic sensitivity. Elevations in plasma glucose in response to glucagon were strongly associated with increases in protein catabolism, suggesting negative impacts of elevated glucagon on protein sparing. Glucagon promoted rapid ketone accumulation suggesting that low ketoacid levels in NES reflect low rates of production. These results demonstrate strong metabolic impacts of glucagon and support the idea that glucagon levels are downregulated in the context of metabolic adaptation to extended fasting. These results suggest that the regulation of carbohydrate and lipid metabolism in NES changes with adiposity, fasting duration and under various constraints of nutrient demands. PMID:24239794

Crocker, Daniel E; Fowler, Melinda A; Champagne, Cory D; Vanderlugt, Anna L; Houser, Dorian S

2014-01-01

275

Response time testing of pressure transmitters in nuclear power plants  

International Nuclear Information System (INIS)

This paper presents a review of the response time testing practice in the nuclear power industry for the safety-related pressure, level, and flow transmitters. Two methods which have been developed and recently validated for response time testing of these transmitters are described. The advantage of the new methods is that they permit remote testing of installed transmitters from the control room while the plant is operating. Also presented in this paper are experimental data on the contribution of sensing lines to the overall response time of pressure sensing systems, and the delays that can result from blockages or air entrapped in the sensing lines

1991-06-03

276

Thermal emittance and response time of a cesium antimonide photocathode  

Science.gov (United States)

Measurements of the intrinsic emittance and response time of a Cs3Sb photocathode are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. Photoemission response time is evaluated using a RF deflecting cavity synchronized to a picosecond laser pulse train. We find that Cs3Sb has both small mean transverse energy, 160 +/- 10 meV at 532 nm laser wavelength, and a prompt response time (below the resolution of our measurement) making it a suitable material for high brightness electron photoinjectors.

Cultrera, Luca; Bazarov, Ivan; Bartnik, Adam; Dunham, Bruce; Karkare, Siddharth; Merluzzi, Richard; Nichols, Matthew

2011-10-01

277

Dose Ramadan Fasting Affects Inflammatory Responses: Evidences for Modulatory Roles of This Unique Nutritional Status via Chemokine Network  

Science.gov (United States)

Objective(s): The impact of fasting in Ramadan as a unique type of nutritional regimen on biochemical and hematological parameters is still an issue of debate. Almost very little is known regarding the regulatory role(s) of this nutritional status on immune responses or inflammation. Materials and Methods: The levels of biochemical parameters were determined using commercial diagnostic kits. Hematological parameters were also examined. We also employed ELISA for detection of CXCL1, CXCL10 and CXCL12 chemokines. The Student-T test was used to compare the values of different parameters obtained in the first and last day of Ramadan fasting by employing SPSS (version 18) software. Results: As our findings demonstrated, there was a markedly difference between before and after Ramadan BMI of the individuals who fast. Our results also revealed that there was a remarkable difference between the levels of total cholesterol, FBS, Triglycerides and LDL before and after Ramadan fasting. Results revealed that among studied hematological parameters only the numbers of platelets were markedly different before and after Ramadan fasting program in individuals who practice fasting. Our results also showed decreased levels of pro-inflammatory CXC chemokines but unaltered levels of homoeostatic ones. Conclusion: The results of this study may reveal that Ramadan fasting is quite safe for normal healthy adults and so very useful in reduction of cholesterol and triglycerides in relation with dyslipidemia. It is also possible to conclude that fasting is important in controlling of inflammation via chemokines.

Akrami Mohajeri, Fateme; Ahmadi, Zahra; Hassanshahi, Gholamhossein; Akrami Mohajeri, Elham; Ravari, Ali; Ghalebi, Seyed Razi

2013-01-01

278

Chitin-based fast responsive pH sensitive microspheres for controlled drug release.  

Science.gov (United States)

Ionically crosslinked chitin microspheres were prepared by using electrostatic droplet method and the drug release from the microspheres was controlled by adjusting external pH. Specifically, chitin was dissolved in NaOH/urea solution at low temperature and functionalized with acrylamide moieties. Acrylamide-modified chitin microspheres with a diameter of 400-500 ?m can be obtained at the voltage of 6 kV and the pump speed of 5 mL h(-1). The formed microspheres were ionically crosslinked with Fe(3+) and then complexed with polycationic polysaccharide chitosan. The structure of the microspheres was characterized by FT IR, SEM, and EDS analyses. Besides, the drug release behavior of the microspheres exhibited a fast responsive and pH sensitive release of vancomycin. It took 30 h for complete release of vancomycin in pH 4.0 buffer and pH 1.2 HCl solution while a fast release (10 min) occurred in pH 7.4 buffer. The results showed that the microspheres could be used in drug delivery. PMID:24507299

Shang, Yu; Ding, Fuyuan; Xiao, Ling; Deng, Hongbing; Du, Yumin; Shi, Xiaowen

2014-02-15

279

Fast time-to-digital converter for position-sensitive radiation detectors with delay line readouts  

Energy Technology Data Exchange (ETDEWEB)

A fast time-to-digital converter (TDC) has been developed for use with position-sensitive radiation detectors having delay line readouts. The device is recommended for detector applications where high position resolution and low distortion are required at high rates. The device has 2 ns time resolution, less than 0.1% differential nonlinearity, and a recovery time of 70 ns. When used with a detector system having a delay line of temporal length tau, the following performance has been achieved: (1) a position digitization of 1 position resolution element per ns of delay line; (2) an average dead time of (3/4 tau + 70) ns; (3) a maximum incident radiation rate of approx. =4/tau; and (4) a maximum conversion rate of approx. = 1/(3tau). Discriminator circuits reduce pile-up distortion to negligible levels for rates as high as those listed above. Finally, two converters may be connected together for synchronous operation as required by 2-dimensional (chi-..gamma..) detectors.

Harder, J.A.

1988-03-15

280

Diamonds as fast timing detectors for MIPS: The HADES proton-beam monitor/start detector  

Energy Technology Data Exchange (ETDEWEB)

Position sensitive mono-crystalline diamond detectors were used successfully as start/beam-monitoring detectors for proton beams (1.2 GeV-3.5 GeV) at rates of up to 3.10{sup 6}/s/10 mm{sup 2}. Two different detector sizes of 3.5 x 3.5 mm{sup 2} (4 segments) and 4.7 x 4.7 mm{sup 2} (8 segments) were used with thicknesses of 300 {mu}m and 500 {mu}m, respectively. Utilizing dedicated fast amplifiers directly attached to the diamond segments, a time resolution of about 100 ps could be achieved with a signal base width of about 8-10 ns and {>=}95% detection efficiency. The signal/RMS-noise ratio amounted to 22 (300 {mu}m) and 26 (500 {mu}m) at rise times of 1.2 ns and 1.3 ns, respectively. The measured time resolution is about a factor of two worse than expected from the signal/noise ratio. A significant variation of rise times was observed which most likely results from rather inhomogeneous intrinsic fields (upcharging effects due to charge trapping). Furthermore, at high rates unreasonably large leakage currents appeared for some detectors which eventually resulted in sudden discharges, tripping the detector bias. These effects seem to depend strongly on the metallization procedure. An optimization of this procedure is currently investigated.

Koenig, Wolfgang; Pietraszko, Jerzy [GSI, Darmstadt (Germany)

2009-07-01

 
 
 
 
281

Diamonds as fast timing detectors for MIPS: The HADES proton-beam monitor/start detector  

International Nuclear Information System (INIS)

Position sensitive mono-crystalline diamond detectors were used successfully as start/beam-monitoring detectors for proton beams (1.2 GeV-3.5 GeV) at rates of up to 3.106/s/10 mm2. Two different detector sizes of 3.5 x 3.5 mm2 (4 segments) and 4.7 x 4.7 mm2 (8 segments) were used with thicknesses of 300 ?m and 500 ?m, respectively. Utilizing dedicated fast amplifiers directly attached to the diamond segments, a time resolution of about 100 ps could be achieved with a signal base width of about 8-10 ns and ?95% detection efficiency. The signal/RMS-noise ratio amounted to 22 (300 ?m) and 26 (500 ?m) at rise times of 1.2 ns and 1.3 ns, respectively. The measured time resolution is about a factor of two worse than expected from the signal/noise ratio. A significant variation of rise times was observed which most likely results from rather inhomogeneous intrinsic fields (upcharging effects due to charge trapping). Furthermore, at high rates unreasonably large leakage currents appeared for some detectors which eventually resulted in sudden discharges, tripping the detector bias. These effects seem to depend strongly on the metallization procedure. An optimization of this procedure is currently investigated.

2009-03-16

282

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

CERN Document Server

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

2014-01-01

283

Fast response methods in the radiation chemistry of lethal damage in intact cells  

International Nuclear Information System (INIS)

The radiation-induced lethal damage in bacteria and mammalian cells involves some important chemical processes which extend up to about 10-2s after the initiating energy deposition. The gas explosion technique, analogous to the use of flash photolysis in photochemistry and pulse radiolysis in radiation chemistry, was applied to examine the kinetics of some of the fast processes within intact cells. The time resolution of this technique is about 100 ?s. Five nanosecond electron pulses and the rapid transition from virtually anoxic (2) to well oxygenated (>105 ppm O2) conditions can be used as the fast probes to determine the time scale of the radiosensitization by oxygen. The apparent differences between the observed intracellular kinetics of the reactions of O2 and of TAN (triacetoneamine-N-oxyl) with target damage and the reactions of these agents with DNA radicals support the view that O2 is not sensitized by reacting directly with DNA damage. In general, the processes described in this review appear to conform to simple bimolecular reaction kinetics. The intracellular reaction rates of the various agents tested are all slower than those expected from the rates of their reactions with radicals in dilute aqueous solution probably due to the complex structure of the cells. (Yamashita, S.)

1979-05-19

284

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

CERN Document Server

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

285

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

Energy Technology Data Exchange (ETDEWEB)

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.

Martin, M.C.; McKinney, W.R.

1998-05-01

286

Fast Tracker: A Hardware Real Time Track Finder for the ATLAS Trigger System  

CERN Document Server

The Fast Tracker (FTK) is an integral part of the trigger upgrade program for the ATLAS detector at the Large Hadron Collider (LHC). As the LHC luminosity approaches its design level of 10^34cm^?2s^?1, the combinatorial problem posed by charged particle tracking becomes increasingly difficult due to the swelling of multiple interactions per bunch crossing (pile-up). The FTK is a highly-parallel hardware system intended to provide high-quality tracks with transverse momentum above 1 GeV/c in real time for online trigger system. The FTK system’s design, based on a mixture of advanced technologies, and expected physics performance will be presented.

Kimura, N; The ATLAS collaboration

2013-01-01

287

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}s at pulse repetition rates of up to 10 kHz. Short pulses between 40 ns and 4 {mu}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.

Valerius, K; Beck, M; Arlinghaus, H; Hannen, V M; Hein, H; Ostrick, B; Streubel, S; Weinheimer, Ch; Zboril, M [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster (Germany); Bonn, J [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz (Germany)], E-mail: valerius@uni-muenster.de

2009-06-15

288

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.)

1993-06-01

289

Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing  

International Nuclear Information System (INIS)

In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from 252Cf (0.5MeV/u9 fission-fragments/cm2 together with more than 3.5×109 neutrons/cm2 and 3×1010?-particles/cm2. This fluence is characteristic for fission experiments. The pre-requisite for the observed signal stability is the application of priming of the diamond material with a strong ?-source for about 48 h. The intrinsic timing resolution of a 100?m thick polycrystalline CVD diamond detector with a size of 1×1 cm2 was determined to ?int=(283±41)ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180?m show an intrinsic timing resolution of ?int=(106±21)ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%. -- Highlights: ? First use of chemical vapor deposited diamond for heavy ions with kinetic energies below 2 MeV per nucleon. ? Fission-fragment time-of-flight measurements with a timing resolution better than 150 ps. ? Radiation-hard fission event trigger to be used in an intense neutron field

2013-06-21

290

Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing  

Energy Technology Data Exchange (ETDEWEB)

In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from {sup 252}Cf (0.5MeV/utiming resolution of a 100?m thick polycrystalline CVD diamond detector with a size of 1×1 cm{sup 2} was determined to ?{sub int}=(283±41)ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180?m show an intrinsic timing resolution of ?{sub int}=(106±21)ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%. -- Highlights: ? First use of chemical vapor deposited diamond for heavy ions with kinetic energies below 2 MeV per nucleon. ? Fission-fragment time-of-flight measurements with a timing resolution better than 150 ps. ? Radiation-hard fission event trigger to be used in an intense neutron field.

Oberstedt, S., E-mail: stephan.oberstedt@ec.europa.eu [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium); Borcea, R.; Bry?, T.; Gamboni, Th.; Geerts, W.; Hambsch, F.-J. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium); Oberstedt, A. [Fundamental Fysik, Chalmers Tekniska Högskola, S-41296 Göteborg (Sweden); Akademin för Naturvetenskap och Technik, Örebro Universitet, S-70182 Örebro (Sweden); Vidali, M. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium)

2013-06-21

291

Quantitative FRET analysis by fast acquisition time domain FLIM at high spatial resolution in living cells.  

Science.gov (United States)

Quantitative analysis in Förster resonance energy transfer (FRET) experiments in live cells for protein interaction studies is still a challenging issue. In a two-component system (FRET and no FRET donor species), fitting of fluorescence lifetime imaging microscopy (FLIM) data gives the fraction of donor molecules involved in FRET (f(D)) and the intrinsic transfer efficiency. But when fast FLIM acquisitions are used to monitor dynamic changes in protein-protein interactions at high spatial and temporal resolutions in living cells, photon statistics and time resolution are limited. In this case, fitting procedures are not reliable, even for single lifetime donors. We introduce the new concept of a minimal fraction of donor molecules involved in FRET (mf(D)), coming from the mathematical minimization of f(D). We find particular advantage in the use of mf(D) because it can be obtained without fitting procedures and it is derived directly from FLIM data. mf(D) constitutes an interesting quantitative parameter for live cell studies because it is related to the minimal relative concentration of interacting proteins. For multi-lifetime donors, the process of fitting complex fluorescence decays to find at least four reliable lifetimes is a near impossible task. Here, mf(D) extension for multi-lifetime donors is the only quantitative determinant. We applied this methodology for imaging the interaction between the bromodomains of TAF(II250) and acetylated histones H4 in living cells at high resolution. We show the existence of discrete acetylated chromatin domains where the minimal fraction of bromodomain interacting with acetylated H4 oscillates from 0.26 to 0.36 and whose size is smaller than half of one micron cube. We demonstrate that mf(D) by itself is a useful tool to investigate quantitatively protein interactions in live cells, especially when using fast FRET-FLIM acquisition times. PMID:18539634

Padilla-Parra, Sergi; Audugé, Nicolas; Coppey-Moisan, Maïté; Tramier, Marc

2008-09-15

292

Planck 2013 results. VII. HFI time response and beams  

CERN Document Server

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

293

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

Science.gov (United States)

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. PMID:17517674

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

2007-01-01

294

Containment response to postulated ex-vessel core meltdown accidents in the fast flux test facility  

International Nuclear Information System (INIS)

An evaluation of the containment response to ex-vessel core meltdown accidents in the Fast Flux Test Facility is discussed. Particular attention is given to the possibility of the molten fuel/steel mixture remaining in a molten form after entering the reactor cavity. For the molten pool configurations considered, significant H2 concentrations were reached in the RCB before the reactor cavity floor was penetrated. The melt-front impacts the pressure transient, not through gas generation, but through penetration into the unlined subcavity resulting in an enhanced sodium-concrete reaction. Hence, if H2 recombination is neglected, then steps would have to be taken to decrease the H2 concentration before the RCB design ressure is reached

1979-08-23

295

Containment response to postulated ex-vessel core meltdown accidents in the fast flux test facility  

Energy Technology Data Exchange (ETDEWEB)

An evaluation of the containment response to ex-vessel core meltdown accidents in the Fast Flux Test Facility is discussed. Particular attention is given to the possibility of the molten fuel/steel mixture remaining in a molten form after entering the reactor cavity. For the molten pool configurations considered, significant H/sub 2/ concentrations were reached in the RCB before the reactor cavity floor was penetrated. The melt-front impacts the pressure transient, not through gas generation, but through penetration into the unlined subcavity resulting in an enhanced sodium-concrete reaction. Hence, if H/sub 2/ recombination is neglected, then steps would have to be taken to decrease the H/sub 2/ concentration before the RCB design ressure is reached.

Pratt, W.T.; Gasser, R.D.; Marchese, A.R.

1979-01-01

296

Response of the rat dunning R3327-AT1 prostate tumor to fractionated fast neutron treatment  

International Nuclear Information System (INIS)

Clinically, certain categories of tumors respond well to fast neutrons. To understand the action of neutrons on tumor tissues, the authors are studying the Dunning rat prostate tumor system. The authors report the treatment response of the anaplastic AT-1 subline (volume doubling, 5.2 days) to 10 fraction of neutrons (0-1.6 Gy per fraction) versus Co-60 (2.4-4.8 Gy per fraction). As with one fraction, the tumors continued to increase in volume for 2 weeks after radiation, followed by a regrowth with no local control. Based on regrowth kinetics, a radiobiologic effectiveness (RBE) of about 3.3 was found, compared with an RBE of 3 for one fraction found in an earlier study

1989-12-01

297

Elements for Response Time Statistics in ERP Transaction Systems  

CERN Document Server

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

298

Time domain modeling of tunable response of graphene  

DEFF Research Database (Denmark)

We present a causal numerical model for time domain simulations of the optical response of graphene. The dielectric function is approximated with a conductivity term, a Drude term and a number of the critical points terms.

Prokopeva, Ludmila; Emani, Naresh K.

2013-01-01

299

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

300

Study on risk-informed determination method of allowed outage time in fast reactor systems  

International Nuclear Information System (INIS)

The present report describes a study aiming at proposing a method to determine the allowed outage time (AOT) after detecting a failure in the equipment that stands by during fast reactor power operation by taking into account risk information rationally. In the present study, an improved risk estimation model based on the previous study was constructed so as to consider properly that the repaired component was returned to the standby state again when the repair action completed within the range of AOT. Based on the improved model, core damage probability (CDP) per each detection of the failure is expressed as a function depending on the elapsed time after failure detection. In addition, there are the upper and lower bound values of CDP, and the CDP changes monotonously (i.e., either decreases or increases) between a pair of both the bound values. If a target value of CDP that is not lower than the lower bound can be given, it is possible to determine AOT, where the point-estimation value of CDP becomes lower than or equal to the target value because CDP depends on the elapsed time. Finally, we developed the procedure for determining the AOT from the view point of maintaining the total core damage frequency less than or equal to a prescribed target value. (author)

2005-01-01

 
 
 
 
301

Response function of accelerated monopole detector in R times T sup 3 space-time  

Energy Technology Data Exchange (ETDEWEB)

The response function of a uniformly accelerated monopole detector interacting with a free scalar field is studied in {ital R}{times}{ital T}{sup 3} space-time. The response function depends not only on the periodicity lengths but also on the direction of the acceleration of the detector.

Abe, O. (Physics Laboratory, Asahikawa College, Hokkaido University of Education, Asahikawa 070, Japan (JP))

1990-03-15

302

An eigenvalue and eigenfunction study of time-dependent fast-neutron spectra in "2"3"2Th  

International Nuclear Information System (INIS)

The pulsed problem for fast neutrons in Th has been studied using the multigroup diffusion equation and eigenfunction expansion method. The time-dependent fast-neutron spectra have been obtained up to 8000 ns inside Th systems with buckling ranging from 0.0 to 0.015 cm"-"2. The results have been obtained using the 27-group BARC data set. It has been shown that for a fast Th system, unlike a fast U system, all the time eigenvalues lie in the continuum and no discrete time eigenvalue exists. A fast Th system behaves more like a non-multiplying system. The spectra shift continuously to lower energies with increasing time. However, pseudo-asymptotic conditions are established in certain time intervals. The start of pseudo-equilibrium conditions and the duration for which they persist is seen to increase with decreasing buckling. The reason for the establishment of pseudo-equilibrium conditions has been discussed. The theoretical results for the instantaneous decay constant inside a 40 cm cube of Th have been compared with the experimental results of Moo et al. (1973). The present results are in good agreement with the above experimental results based on the "2"3"9Pu detector. (author)

1986-01-01

303

Fast response varifocal lenses using KTa(1-x)Nb(x)O3 crystals and a simulation method with electrostrictive calculations.  

Science.gov (United States)

We fabricated cylindrical varifocal lenses with fast responses by using the strong Kerr effect of KTa(1-x)Nb(x)O(3) (KTN) single crystals. We observed focus shifts of up to 87 mm with the assistance of a 250 mm focal length lens, which corresponds to a focus shift from infinity to 720 mm by the KTN lens itself. The response time was as fast as 1 ?s. We also present a simulation method for calculating refractive index distributions in KTN single crystals, which is essential when designing the lens. The method is characterized by the strain contribution, which has not conventionally been typical of electro-optic simulations. We used this method to explain the refractive index modulations that are characteristic of the varifocal lenses. PMID:22505071

Imai, Tadayuki; Yagi, Shogo; Toyoda, Seiji; Miyazu, Jun; Naganuma, Kazunori; Kawamura, Sohan; Sasaura, Masahiro; Fujiura, Kazuo

2012-04-01

304

Preoperative Management of Surgical Patients by “Shortened Fasting Time”: A Study on the Amount of Total Body Water by Multi-Frequency Impedance Method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aim: Preoperative fasting is an established procedure to be practiced for patients before surgery, but optimal preoperative fasting time still remains controversial. The aim of this study was to investigate the effect of “shortened preoperative fasting time” on the change in the amount of total body water (TBW) in elective surgical patients. TBW was measured by multi-frequency impedance method.

Taniguchi, Hideki; Sasaki, Toshio; Fujita, Hisae

2012-01-01

305

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

306

Measure of the speed of gamma-rays as a test of the performance of a fast timing coincidence system  

International Nuclear Information System (INIS)

The speed of the gamma-rays obtained from positron annihilation has been measured as a test of the long-term stability of a fast timing coincidence system. The value c=(2.9978±0.0002)108 m/s has been obtained, whose precision is the best among those obtained from nuclear timing techniques. ((orig.))

1995-02-15

307

A Fast-Time Study of Aircraft Reordering in Arrival Sequencing and Scheduling  

Science.gov (United States)

In order to ensure that the safe capacity of the terminal area is not exceeded, Air Traffic Management ATM often places restrictions on arriving flights transitioning from en route airspace to terminal airspace. This restriction of arrival traffic is commonly referred to as arrival flow management, and includes techniques such as metering, vectoring, fix-load balancing, and the imposition of miles-in-trail separations. These restrictions are enacted without regard for the relative priority which airlines may be placing on individual flights based on factors such as crew criticality, passenger connectivity, critical turn times, gate availability, on-time performance, fuel status, or runway preference. The development of new arrival flow management techniques which take into consideration priorities expressed by air carriers will likely reduce the economic impact of ATM restrictions on the airlines and lead to increased airline economic efficiency by allowing airlines to have greater control over their individual arrival banks of aircraft. NASA and the Federal Aviation Administration (FAA) have designed and developed a suite of software decision support tools (DSTs) collectively known as the Center TRACON Automation System (CTAS). One of these tools, the Traffic Management Advisor (TMA) is currently being used at the Fort Worth Air Route Traffic Control Center to perform arrival flow management of traffic into the Dallas/Fort Worth airport (DFW). The TMA is a time-based strategic planning tool that assists Traffic Management Coordinators (TMCs) and En Route Air Traffic Controllers in efficiently balancing arrival demand with airport capacity. The primary algorithm in the TMA is a real-time scheduler which generates efficient landing sequences and landing times for arrivals within about 200 no a. from touchdown. This scheduler will sequence aircraft so that they arrive in a first- come - first-served (FCFS) order. While FCFS sequencing establishes a fair order based on estimated times of arrival, it does not take into account individual airline priorities among incoming flights. NASA is exploring the possibility of allowing airlines to express relative arrival priorities to air traffic management through the development of new CTAS scheduling algorithms which take into consideration airline arrival preferences. The accommodation of airline priorities in arrival sequencing and scheduling would under most circumstances result in a deviation from a "natural" or FCFS arrival order. As a First step toward developing airline influenced sequencing algorithms, an investigation was conducted to determine the feasibility of reordering arrival traffic from a strict FCFS sequence. A fast-time simulation has been developed which allows statistical evaluation of sequencing and scheduling algorithms for arrival traffic at the Dallas/Fort Worth Airport. In contrast to real-time simulation or field tests, which would require on the order of ninety minutes to examine a single traffic rush period, the fast-time simulation allows examination of multiple rush periods in a matter of seconds.

Carr, Greg; Neuman, Frank; Tobias, Leonard (Technical Monitor)

1998-01-01

308

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

2013-07-01

309

Fast magnetosonic wave excitation by an array of wires with time-modulated currents  

Directory of Open Access Journals (Sweden)

Full Text Available The excitation of Fast Magnetosonic (FMS waves by a cylindrical array of parallel tethers carrying time-modulated current is discussed. The tethers would fly vertical in the equatorial plane, which is perpendicular to the geomagnetic field when its tilt is ignored, and would be stabilized by the gravity gradient. The tether array would radiate a single FMS wave. In the time-dependent background made of geomagnetic field plus radiated wave, plasma FMS perturbations are excited in the array vicinity through a parametric instability. The growth rate is estimated by truncating the evolution equation for FMS perturbations to the two azimuthal modes of lowest order. Design parameters such as tether length and number, required power and mass are discussed for Low Earth Orbit conditions. The array-attached wave structure would have the radiated wave controlled by the intensity and modulation frequency of the currents, making an active experiment on non-linear low frequency waves possible in real space plasma conditions.

G. Sanchez-Arriaga

2010-02-01

310

Computationally Efficient Partial Crosstalk Cancellation in Fast Time-Varying DSL Crosstalk Environments  

Directory of Open Access Journals (Sweden)

Full Text Available Line selection (LS, tone selection (TS, and joint tone-line selection (JTLS partial crosstalk cancellers have been proposed to reduce the online computational complexity of far-end crosstalk (FEXT cancellers in digital subscriber lines (DSL. However, when the crosstalk profile changes rapidly over time, there is an additional requirement that the partial crosstalk cancellers, particularly the LS and JTLS schemes, should also provide a low preprocessing complexity. This is in contrast to the case for perfect crosstalk cancellers. In this paper, we propose two novel channel matrix inversion methods, the approximate inverse (AI and reduced inverse (RI schemes, which reduce the recurrent complexity of the LS and JTLS schemes. Moreover, we propose two new classes of JTLS algorithms, the subsort and Lagrange JTLS algorithms, with significantly lower computational complexity than the recently proposed optimal greedy JTLS scheme. The computational complexity analysis of our algorithms shows that they provide much lower recurrent complexities than the greedy JTLS algorithm, allowing them to work efficiently in very fast time-varying crosstalk environments. Moreover, the analytical and simulation results demonstrate that our techniques are close to the optimal solution from the crosstalk cancellation point of view. The results also reveal that partial crosstalk cancellation is more beneficial in upstream DSL, particularly for short loops.

Lee M. Garth

2007-01-01

311

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

312

Time resolved measurement of FEL micropulses using fast hot electron bolometers  

International Nuclear Information System (INIS)

Radiation at 3THz or light of a 100?m wavelength generated with the THz-FEL at the Institute of Scientific and Industrial Research (ISIR), Osaka University is measured using two superconducting hot-electron bolometers (SHEB); one with a NbN (normal superconductor) detector and the other a YBCO (YBa2Cu3O7, high temperature superconductor) detector. Both detectors are fast enough to separately measure FEL micropulse at interval of 9.2 ns, which comprise four families of independent FEL micropulses. The single-shot time spectra, however, include significant amplitude noises compared to signals and hence it is difficult to analyze these spectra quantitatively. We try some kinds of numerical methods to reduce noises of the spectra measured with the YBCO detector and find the so-called MMSE-STSA (Minimum Mean-Square Error Short-Time Spectral Amplitude Estimator) method can significantly reduce effects of the noises. As a result, it is experimentally shown that four families of FEL micropulses develop independently and differently in the power saturation region. (author)

2012-08-08

313

Gigantic enhancement in response and reset time of ZnO UV nanosensor by utilizing Schottky contact and surface functionalization.  

Science.gov (United States)

UV response of ZnO nanowire nanosensor has been studied under ambient condition. By utilizing Schottky contact instead of Ohmic contact in device fabrication, the UV sensitivity of the nanosensor has been improved by four orders of magnitude, and the reset time has been drastically reduced from approximately 417 to approximately 0.8 s. By further surface functionalization with function polymers, the reset time has been reduced to approximately 20 ms even without correcting the electronic response of the measurement system. These results demonstrate an effective approach for building high response and fast reset UV detectors. PMID:19654881

Zhou, Jun; Gu, Yudong; Hu, Youfan; Mai, Wenjie; Yeh, Ping-Hung; Bao, Gang; Sood, Ashok K; Polla, Dennis L; Wang, Zhong Lin

2009-05-11

314

High-Voltage Power Supply With Fast Rise and Fall Times  

Science.gov (United States)

A special-purpose high-voltage power supply can be electronically switched on and off with fast rise and fall times, respectively. The output potential is programmable from 20 to 1,250 V. An output current of 50 A can be sustained at 1,250 V. The power supply was designed specifically for electronically shuttering a microchannel plate in an x-ray detector that must operate with exposure times as short as 1 ms. The basic design of the power supply is also adaptable to other applications in which there are requirements for rapid slewing of high voltages. The power-supply circuitry (see figure) includes a preregulator, which is used to program the output at 1/30 of the desired output potential. After the desired voltage has been set, the outputs of a pulse width modulator (PWM) are enabled and used to amplify the preregulator output potential by 30. The amplification is achieved by use of two voltage doublers with a transformer that has two primary and two secondary windings. A resistor is used to limit the current by controlling the drive voltage of two field-effect transistors (FETs) during turn-on of the PWM. A pulse transformer is used to turn on four FETs to short-circuit four output capacitors when the outputs of the PWM have been disabled. The most notable aspects of the performance of the power supply are a rise time of only 80 s and a fall time of only 60 s at a load current of 50 A or less. Another notable aspect is that the application of a 0-to-5-V square wave to a shutdown pin of the PWM causes the production of a 0-to-1,250-V square wave at the output terminals.

Bearden, Douglas B.; Acker, Richard M.; Kapuslka, Robert E.

2007-01-01

315

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

2013-01-01

316

Modeling fast electron dynamics with real-time time-dependent density functional theory: application to small molecules and chromophores  

Energy Technology Data Exchange (ETDEWEB)

The response of matter to external fields forms the basis for a vast wealth of fundamental physical processes ranging from light harvesting to nanoscale electron transport. Accurately modeling ultrafast electron dynamics in excited systems thus o_ers unparalleled insight, but requires an inherently non-linear time-resolved approach. To this end, an e_cient and massively parallel real-time real-space time-dependent density functional theory (RT-TDDFT) implementation in NWChem is presented. The implementation is first validated against linearresponse TDDFT and experimental results for a series of molecules subjected to small electric field perturbations. Second, non-linear excitation of green fluorescent protein is studied, which shows a blue-shift in the spectrum with increasing perturbation, as well as a saturation in absorption. Next, the charge dynamics of optically excited zinc porphyrin is presented in real-time and real-space, with relevance to charge injection in photovoltaic devices. Finally, intermolecular excitation in an adenine-thymine base pair is studied using the BNL range separated functional [Baer, R.; Neuhauser, D. Phys. Rev. Lett. 2005, 94, 043002], demonstrating the utility of a real-time approach in capturing charge transfer processes.

Lopata, Kenneth A.; Govind, Niranjan

2011-05-10

317

Time gap between oocyst shedding and antibody responses in mice infected with Cryptosporidium parvum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We observed the time gap between oocyst shedding and antibody responses in mice (3-week-old C57BL/6J females) infected with Cryptosporidium parvum. Oocyst shedding was verified by modified acid-fast staining. The individually collected mouse sera were assessed for C. parvum IgM and IgG antibodies by enzyme-linked immunosorbent assay from 5 to 25 weeks after infection. The results showed that C. parvum oocysts were shed from day 5 to 51 post-infection (PI). The IgM antibody titers to C. parvum...

Yu, Jae-ran; Lee, Soo-ung

2007-01-01

318

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

Hornstrup, Allan; Linden-Vørnle, Michael

2013-01-01

319

Combined, Time-Resolved ?-Ray and Fast Neutron Radiography for Contraband Detection  

International Nuclear Information System (INIS)

Soreq NRC and PTB are developing dual-probe (gamma-ray and fast neutron) high-spatial-resolution radiography for detection of explosives and special nuclear materials (SNM). The explosives are detected by Fast Neutron Resonance Radiography (FNRR), that exploits the specific energy-dependent cross-section characteristics of several low-Z elements in the neutron energy-range En=1-10 MeV. The neutrons are produced in 1-2 ns bursts using a pulsed beam of 12 MeV deuterons impinging on a thick Be target. Neutron spectroscopy is performed by means of a novel, integral-mode variant of the time of flight (TOF) technique. This method holds promise for detecting a broad range of conventional and improvised explosives, by determining the identity and density distribution of light elements such as C, N and O within an inspected object. It is expected that the high spatial resolution and the capability of operating at very high counting rates particular to this method will ultimately permit a significant improvement in baggage screening capabilities at airports, in terms of enhanced throughput and operator-independent detection of sheet explosives. In addition to neutrons, the d-Be reaction also yields prompt gamma-rays in the 0.5-6 MeV range. These gamma-rays are readily distinguished from neutrons by TOF. By taking the attenuation ratio of neutrons to gamma-rays through the inspected object it is possible to distinguish materials according to their atomic number. For example, the ratio for tungsten is higher by a factor of 4.2 and 2.3 than that of water and iron, respectively. The method produces high resolution images and also has the potential to detect small quantities of SNM. In this paper we shall describe the time-resolved neutron-gamma ray imaging detector and present studies of various detector parameters, such as spatial and energy resolution, imaging and material discrimination capabilities. (author)

2007-11-26

320

Monitoring the immune response using real-time PCR.  

Science.gov (United States)

Induction of an immune response to a particular antigen is the basis of vaccination. This has been done for years to prevent infectious diseases, and has the potential for the treatment of cancer. The immune response is nowadays more precisely modulated rather than simply induced, like in case of immunotherapy of allergic diseases. Likewise, autoimmune diseases are associated with an inappropriate immune response, and many efforts are made for specifically inhibiting this unwanted response. A possible line of attack is the induction of an antigen-specific immune tolerance, which also has a use in the field of transplantation, where allogeneic responses are deleterious for the graft. In all of these fields of fundamental and clinical medicine, the modulation of immune response requires the assistance of laboratory tests, among which real-time PCR appears more and more helpful. This chapter describes a protocol to quantify immune-related mRNAs using reverse transcription-real-time PCR. The transcripts can be quantified in cultured cells or in cultured whole blood, after an incubation period in the presence of the antigen to which the immune response is analyzed. This is the typical approach to evaluate the efficacy of a vaccine. The transcripts can also be quantified directly in the biological sample, giving information about the in vivo immune status of the individual. The techniques to achieve these different methods are described, and are illustrated by the analysis of the response against the toxoid tetanus antigen. PMID:18839121

Stordeur, Patrick

2009-01-01

 
 
 
 
321

SeaMon-HC Buoy. A specific real-time-lightweight-moored platform as a tool for fast hydrocarbon detection  

Science.gov (United States)

The present paper-work describes the design, last development stages and the derived results from a specific buoy platform for fast hydrocarbon detection in seawater. Under the name of SeaMon-HC, (Patent No. P200302219/8) the buoy represents a very chief tool for coastal monitoring, mainly surrounding areas with a high oil-spill risk level, like harbours, off-shore fish farming, beaches and so on. Nowadays, the Macaronesian area has nine units working in real-time, under the frame of the Red ACOMAR Network. The main innovative aspect from this buoy is the detection system. It's based in polymer technology, working as a resistance, who increase its value when the pollutant on water surface is detected. The response time from the sensor is a direct function of the hydrocarbon volatility level. For hydrocarbons with high volatility levels (like petrol), the sensor needs less time (around 3 minutes) than others with less volatility such as oils. SeaMon-HC is an autonomous, modular, reusable and a very low-cost development integrated by four subsystems (SS): SS-Flotation (different materials and shapes available); SS-Sensors (hydrocarbon detector and additional sensors -up to 15-, to solve specific sensor configuration requirements); SS-Power Supply (equipped in its basic configuration with a couple of solar modules and two 12V batteries) and the SS-Communication (based on a RF or GSM/GPRS modem technology, with a selectable communication frequency). All SeaMon-HC units, as well the rest of the ODAS buoys who joint together the Red ACOMAR Network, works in real-time, sending the collected information to the control centre that manages the communications, providing data, in a useful form (as a web site), to diverse socio-economic important sectors which make an exhaustive use of the littoral in the Macaronesian region. The access to the information by the users is done through a specific GIS software application.

Barrera, C.; Rueda, M. J.; Moran, R.; Llerandi, C.; Llinas, O.

2009-04-01

322

Real-time 3D medical structure segmentation using fast evolving active contours  

Science.gov (United States)

Segmentation of 3D medical structures in real-time is an important as well as intractable problem for clinical applications due to the high computation and memory cost. We propose a novel fast evolving active contour model in this paper to reduce the requirements of computation and memory. The basic idea is to evolve the brief represented dynamic contour interface as far as possible per iteration. Our method encodes zero level set via a single unordered list, and evolves the list recursively by adding activated adjacent neighbors to its end, resulting in active parts of the zero level set moves far enough per iteration along with list scanning. To guarantee the robustness of this process, a new approximation of curvature for integer valued level set is proposed as the internal force to penalize the list smoothness and restrain the list continual growth. Besides, list scanning times are also used as an upper hard constraint to control the list growing. Together with the internal force, efficient regional and constrained external forces, whose computations are only performed along the unordered list, are also provided to attract the list toward object boundaries. Specially, our model calculates regional force only in a narrowband outside the zero level set and can efficiently segment multiple regions simultaneously as well as handle the background with multiple components. Compared with state-of-the-art algorithms, our algorithm is one-order of magnitude faster with similar segmentation accuracy and can achieve real-time performance for the segmentation of 3D medical structures on a standard PC.

Wang, Xiaotao; Wang, Qiang; Hao, Zhihui; Xu, Kuanhong; Guo, Ping; Ren, Haibing; Jang, Wooyoung; Kim, Jung-bae

2014-03-01

323

Fast time-correlated multi-element photon detector and method  

Energy Technology Data Exchange (ETDEWEB)

Photons emitted from a sample responsive to being excited by laser pulses are directed through a prism onto a photomultiplier tube having several spaced-apart anodes. The prism alters the path of each photon as a function of its wavelength so that the wavelength determines the anode to which the photon is directed. Taps of first and second delay lines that are coupled to respective alternating anodes. When an anode receives the photon, it generates a pulse that propagates through the delay line in opposite directions from its associated tap. A timer determines first and second times from the laser pulse to the pulse reaching the first and second ends of the delay line. The difference between the first and second times corresponds to the wavelength of the emitted photon and the sum of the first and second times corresponds to the emission delay of the emitted photon.

Hayden, Carl C. (Dublin, CA); Chandler, David W. (Livermore, CA); Luong, A. Khai (Dublin, CA)

2007-12-18

324

Fast Turn-Off Times Observed in Experimental 4H SiC Thyristors  

Science.gov (United States)

Room temperature measurements of the turn-off time (t(sub q)) are reported for several packaged, npnp developmental power thyristors based on 4H-type SiC and rated 400 V, 2 A. Turn-off is effected by a 50 V pulse of applied reverse voltage, from a state of a steady 1 A forward current. Plots of t(sub q) against the ramp rate (dV(sub AK)/dt) of reapplied forward voltage are presented for preset values of limiting anode-to-cathode voltage (V(sub AK,max)). The lowest t(sub q) measured was about 180 ns. A rapid rise of these t(sub q) curves was observed for values of V(sub AK,max) that are only about a fifth of the rated voltage, whereas comparative t(sub q) plots for a commercial, fast turn-off, Si-based thyristor at a proportionately reduced V(sub AK,max) showed no such behavior. Hence these SiC thyristors may have problems arising from material defects or surface passivation. The influence the R-C-D gate bypass circuit that was used is briefly discussed.

Niedra, Janis M.

2006-01-01

325

Fast Timing Analysis of Cygnus X-1 using SPI on board INTEGRAL  

CERN Document Server

For the very first time, we report the high frequency analysis of Cyg X-1 up to hard X-ray using SPI on-board INTEGRAL. After analyzing the possible contribution fromthe background, and using INTEGRAL archive from March 2005 to May 2008, Power Density Spectra (PDS) were obtained until 130 keV. First, we show that their overall shape is very similar to that observed at lower energies, as they are well described by sets of Lorentzians. The strength of this fast variability (up to 40 Hz) does not drop at high energy since we show that it remains at ~25% rms, even in the highest energy bands. Second, the hard X-ray variability patterns of Cyg X-1 are state dependent: the softer the spectrum (or the lower the hardness ratio), the lower the total fractional variability and the higher the typical frequencies observed. The strength of total variability as a function of energy and state is then investigated. By comparison with simultaneous and published RXTE/PCA data, we showed that in the hard state, it remains quite...

Cabanac, C; Jourdain, E

2011-01-01

326

Fast-Time Evaluations of Airborne Merging and Spacing in Terminal Arrival Operations  

Science.gov (United States)

NASA researchers are developing new airborne technologies and procedures to increase runway throughput at capacity-constrained airports by improving the precision of inter-arrival spacing at the runway threshold. In this new operational concept, pilots of equipped aircraft are cleared to adjust aircraft speed to achieve a designated spacing interval at the runway threshold, relative to a designated lead aircraft. A new airborne toolset, prototypes of which are being developed at the NASA Langley Research Center, assists pilots in achieving this objective. The current prototype allows precision spacing operations to commence even when the aircraft and its lead are not yet in-trail, but are on merging arrival routes to the runway. A series of fast-time evaluations of the new toolset were conducted at the Langley Research Center during the summer of 2004. The study assessed toolset performance in a mixed fleet of aircraft on three merging arrival streams under a range of operating conditions. The results of the study indicate that the prototype possesses a high degree of robustness to moderate variations in operating conditions.

Krishnamurthy, Karthik; Barmore, Bryan; Bussink, Frank; Weitz, Lesley; Dahlene, Laura

2005-01-01

327

A fast least-squares arrival time estimator for scintillation pulses  

International Nuclear Information System (INIS)

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

1994-08-01

328

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

329

Measurement of time-dependent fast neutron energy spectra in a depleted uranium assembly  

International Nuclear Information System (INIS)

Time-dependent neutron energy spectra in the range 0.6 to 6.4 MeV have been measured in a depleted uranium assembly. By selecting windows in the time range 0.9 to 82 ns after the beam pulse, it was possible to observe the change of the neutron energy distributions from spectra of predominantly 4 to 6 MeV neutrons to spectra composed almost entirely of fission neutrons. The measured spectra were compared to a Monte Carlo calculation of the experiment using the ENDF/B-IV data file. At times and energies at which the calculation predicted a fission spectrum, the experiment agreed with the calculation, confirming the accuracy of the neutron spectroscopy system. However, the presence of discrepancies at other times and energies suggested that there are significant inconsistencies in the inelastic cross sections in the 1 to 6 MeV range. The time response generated concurrently with the energy spectra was compared to the Monte Carlo calculation. From this comparison, and from examination of time spectra measured by other workers using 235U and 237Np fission detectors, it would appear that there are discrepancies in the ENDF/B-IV cross sections below 1 MeV. The predicted decay rates were too low below and too high above 0.8 MeV

1980-01-01

330

Reaction-time response of a large commercial aircraft  

International Nuclear Information System (INIS)

The reaction-time response of a large commercial aircraft is defined. The aircraft is examined as a thin-walled tubular missile. The impact is assumed soft, and the target's effect on the reaction-time response is neglected. The reaction-time response is defined assuming a normal impact on a rigid wall. The reaction-time response is defined with the analytical Riera method and with the numerical explicit finite element method. The Riera force history is solved with the finite difference method. For the finite element method, two codes are used: Abaqus/Explicit and LS-DYNA. Focus is on the sensitivity study of the used methods. The outer shell of the aircraft is modeled, and an approximation for the mass-distribution is made. Sensitivity to modeling assumptions is studied in order to get information on the adequacy of modeling. The results indicate relatively small sensitivity to modeling assumptions. The wings should be modeled more accurately in order to obtain the dominant frequency response in global structural analysis. (author)

2011-10-24

331

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

332

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

International Nuclear Information System (INIS)

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

333

The Long-Time Behaviour of Fast Power Reactors with Pu-Recycling  

International Nuclear Information System (INIS)

A study is made of the long-time behaviour of fast power reactors with Pu-recycling, taking into account the internal core and blanket management and the external management of the fuel concerning the reprocessing and refabricating plants. The investigations are based on a suitable reactor model which includes a cylindrical reactor core, an axial and radial blanket, and the external plants for reprocessing the irradiated fuel and refabricating the fuel elements. Charging and discharging of the core and blanket elements are treated as discontinuous processes. The calculation of the U and Pu output of the core and blankets at a given time is performed in two steps: first the well-known burn-up equations for the fuel with space-dependent coefficients are solved, yielding the space-dependent U and Pu concentrations in the irradiated and discharged elements. Then the total U and Pu content of the discharged elements follow by volume integration. The coefficients of the burn-up equations are determined by the one-group neutron flux ?(r, z) and the microscopic one-group cross-sections o(r, z) for absorption and capture at the points of neutron irradiation. To limit the numerical efforts by calculating the long-time behaviour, the one-group constants are regarded as time independent. The feedback of the burn-up of the fuel on the neutron flux and spectrum can be taken into account for a first-order approximation by calculating the one-group constants for an average burn-up state of the reactor. By this procedure it is possible to calculate the U and Pu content of the discharged elements with sufficient accuracy. The one-group neutron flux of the average state of the reactor is normalized to the given total power of the reactor. From these conditions, the U and Pu output of the core, axial and radial blanket are calculated as functions of time, thereby taking the time-dependent initial composition of the core elements into account completely. The initial composition of the fuel elements is re-calculated for every fuel cycle by satisfying two algebraic conditions for each core zone. The first condition maintains criticality of the reactor by keeping the difference of neutron production and consumption per cm3 and sec constant in respect to time. The second condition keeps the total number of the heavy nuclei per cm3 constant. The breeding gain is also determined by these conditions. The numerical results for a 1000-MW(e) sodium-cooled reactor show a strong coupling between the operation of the radial blanket by joint reprocessing of the core and radial blanket elements. This is shown by the time dependence of.the Pu-isotopic composition in the fresh and irradiated fuel elements. Furthermore, it is shown that this time behaviour leads to time variations of the amount of Pu which must be charged into the core for criticality, and the breeding gain of the system. (author)

1968-05-01

334

Lithium niobate stress gauge current diagnostic for noninductive measurement of fast-rise-time multimegampere currents  

International Nuclear Information System (INIS)

Accurate modeling of load behavior in Z-pinch plasma radiation sources driven by high-current generators requires the measurement of fast-rise-time multimegampere currents close to the load. Conventional current diagnostics mounted in inductive cavities (such as B loops and Rogowski coils) fail at small radius because of electrical breakdown produced by high dI/dt. In this paper, we describe the use of large-signal, nanosecond-time-resolution lithium niobate piezoelectric stress gauges to directly measure the magnetic pressure B2/2?0=?0I2/8?2r2 generated at radius r by a current I flowing in a radial transmission line. Current measurements have been performed at radius r=2.54x10-2 m on Sandia National Laboratories' Proto-II (10 TW) and SATURN (30 TW) gas puff Z-pinch experiments with maximum currents of 10.1 MA and dI/dt to 2.1x1014 A/s. Comparisons with Faraday rotation and B current diagnostic measurements at large radius are presented. Bremsstrahlung noise problems unique to the SATURN gas puff source are discussed. For a Y-cut lithium niobate stress gauge on a pure tungsten electrode, current densities up to I/2?r=78 MA/m can be measured before the electrode yield strength and the piezoelectric operating stress limit are exceeded. Above the Hugoniot elastic limit of the electrode material, the dynamic range and accuracy of the diagnostic are greatly reduced, but it appears that the technique can be extended to higher current densities using an X-cut quartz piezoelectric element and a tungsten-sapphire electrode impedance stack

1990-11-15

335

Fast and wide-band response infrared detector using porous PZT pyroelectric thick film  

Science.gov (United States)

Porous lead zirconate titanate (PbZr0.3Ti0.7O3, PZT30/70) thick films and detectors for pyroelectric applications have been fabricated on alumina substrates by screen-printing technology. Low temperature sintering of PZT thick films have been achieved at 850 °C by using Li2CO3 and Bi2O3 sintering aids. The microstructure of PZT thick film has been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The dielectric properties were measured using HP 4284 at 1 kHz under 25 °C. The permittivity and loss tangent of the thick films were 94 and 0.017, respectively. Curie temperature of PZT thick film was 425 °C as revealed by dielectric constant temperature measurement. The pyroelectric coefficient was determined to be 0.9 × 10-8 Ccm-2 K-1 by dynamic current measurement. Infrared detector sensitive element of dual capacitance was fabricated by laser directly write technology. Detectivity of the detectors were measured using mechanically chopped blackbody radiation. Detectivity ranging from 1.23 × 108 to 1.75 × 108 (cm Hz1/2 W-1) was derived at frequency range from 175.5 Hz to 1367 Hz, and D*'s -3 dB cut-off frequency bandwidth was 1.2 kHz. The results indicate that the infrared detectors based on porous thick films have great potential applications in fast and wide-band frequency response conditions.

Wu, C. G.; Sun, X. Y.; Meng, J.; Luo, W. B.; Li, P.; Peng, Q. X.; Luo, Y. S.; Shuai, Y.

2014-03-01

336

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

337

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

2009-06-01

338

Assessing the Value of Regulation Resources Based on Their Time Response Characteristics  

Energy Technology Data Exchange (ETDEWEB)

Fast responsive regulation resources are potentially more valuable as a power system regulation resource (more efficient) because they allow applying controls at the exact moment and in the exact amount as needed. Faster control is desirable because it facilitates more reliable compliance with the NERC Control Performance Standards at relatively lesser regulation capacity procurements. The current California ISO practices and markets do not provide a differentiation among the regulation resources based on their speed of response (with the exception of some minimum ramping capabilities). Some demand response technologies, including some generation and energy storage resources, can provide quicker control actions. California ISO practices and markets could be updated to welcome more fast regulation resources into the California ISO service area. The project work reported in this work was pursuing the following objectives: • Develop methodology to assess the relative value of generation resources used for regulation and load following California ISO functions • This assessment should be done based on physical characteristics including the ability to quickly change their output following California ISO signals • Evaluate what power is worth on different time scales • Analyze the benefits of new regulation resources to provide effective compliance with the mandatory NERC Control Performance Standards • Evaluate impacts of the newly proposed BAAL and FRR standards on the potential value of fast regulation and distributed regulation resources • Develop a scope for the follow-up projects to pave a road for the new efficient types of balancing resources in California. The work included the following studies: • Analysis of California ISO regulating units characteristics • California ISO automatic generation system (AGC) analysis • California ISO regulation procurement and market analysis • Fast regulation efficiency analysis • Projection of the California ISO load following and regulation requirements into the future • Value of fast responsive resources depending on their ramping capability • Potential impacts of the balancing authority area control error limit (BAAL), which is a part of the newly proposed NERC standard “Balancing Resources and Demand” • Potential impacts of the Western Electricity Coordinating Council (WECC) frequency responsive reserve (FRR) standard • Recommendations for the next phase of the project. The following main conclusions and suggestions for the future have been made: • The analysis of regulation ramping requirements shows that the regulation system should be able to provide ramps of at least 40-60 MW per minute for a period up to 6 minutes. • Evaluate if changes are needed in the California ISO AGC system to effectively accommodate new types of fast regulation resources and minimize the California ISO regulation procurement. • California ISO may consider creating better market opportunities for and incentives for fast responsive resources. • An additional study of low probability high ramp events can be recommended to the California ISO. • The California ISO may be willing to consider establishing a more relaxed target CPS2 compliance level. • A BAAL-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the BAAL standard and its numerical values for the California ISO. The study may involve an assessment of advantages of the distributed frequency-based control for the California ISO system. The market-related issues that arise in this connection can be also investigated. • A FRR-related study can be recommended for the California ISO as soon as more clarity is achieved concerning the actual enforcement of the FRR standard and its numerical values for the California ISO.

Makarov, Yuri V.; Lu, Shuai; Ma, Jian; Nguyen, Tony B.

2008-06-01

339

Critical response time (time available to implement effective measures for epidemic control): Model building and evaluation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The time available to implement successful control measures against epidemics was estimated. Critical response time (CRT), defined as the time interval within which the number of epidemic cases remains stationary (so that interventions implemented within CRT may be the most effective or least costly), was assessed during the early epidemic phase, when the number of cases grows linearly over time. The CRT was calculated from data of the 2001 foot-and-mouth disease (FMD) epidemic that occurred ...

Rivas, A. L.; Tennenbaum, S. E.; Aparicio, J. P.; Hoogesteijn, A. L.; Mohammed, H. O.; Castillo-cha?vez, C.; Schwager, S. J.

2003-01-01

340

Timing and Causality in the Generation of Learned Eyelid Responses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The cerebellum-red nucleus-facial motoneuron (Mn) pathway has been reported as being involved in the proper timing of classically conditioned eyelid responses. This special type of associative learning serves as a model of event timing for studying the role of the cerebellum in dynamic motor control. Here, we have re-analyzed the firing activities of cerebellar posterior interpositus (IP) neurons and orbicularis oculi (OO) Mns in alert behaving cats during classical eyeblink conditioning, usi...

Sa?nchez-campusano, Raudel; Gruart, Agne?s; Delgado-garci?a, Jose? M.

2011-01-01

 
 
 
 
341

Effect of the fissile bead's and thermocouple wires' sizes on the response time of a fission couple  

Science.gov (United States)

The fission couple is proposed as a fast response miniature neutron detector in the measurement of time dependent energy depositions within the fissile material based on theoretical analysis, but the response time of a fission couple is relatively slow in practice. The time lag originated from heat transfer process was demonstrated to be the dominating factor by theoretical simulations and experimental verification in this paper. The response of a fission couple as a function of the bead size and the thermocouple wires' sizes are simulated using ANSYS workbench. The decrease of wires' diameter results in the decrease of response time, and the increase of bead's diameter leads to a slight increase of response time. During a pulse heating transient in the fuel of Chinese Fast Burst Reactor II with a FWHM of 181?s, the time lag originated from heat transfer process is about tens of microseconds for the peaks of the change rate of temperature, and is of the order of milliseconds to achieve 85% of the temperature rise for a typical fission couple with a ? 1 mm fissile bead and two ? 0.05 mm thermocouple wires. The results obtained provide foundation for the optimization of fission couples.

Liang, Wenfeng; Lu, Yi; Li, Meng; Fan, Xiaoqiang; Lu, Wei

2014-05-01

342

Multiplex Fast Real-Time PCR for Quantitative Detection and Identification of cos- and pac-Type Streptococcus thermophilus Bacteriophages? †  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The fermentation of milk by Streptococcus thermophilus is a widespread industrial process that is susceptible to bacteriophage attack. In this work, a preventive fast real-time PCR method for the detection, quantification, and identification of types of S. thermophilus phages in 30 min is described.

Del Rio, Beatriz; Marti?n, Mari?a Cruz; Marti?nez, Noelia; Magada?n, Alfonso H.; Alvarez, Miguel A.

2008-01-01

343

Multiplex Fast Real-Time Polymerase Chain Reaction for quantitative detection and identification of cos and pac Streptococcus thermophilus bacteriophages  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The fermentation of milk by S. thermophilus is a widespread industrial process that is susceptible to bacteriophage attacks. In this work, it is described a preventive Fast Real-time PCR method for the detection, quantification and typification of S. thermophilus phages in thirty minutes.

Ri?o Lagar, Beatriz Del; Marti?n Marti?n, M. Cruz; Marti?nez, Noelia; Herna?ndez Magada?n, Alfonso; A?lvarez Gonza?lez, Miguel A?ngel

2008-01-01

344

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

345

Determinants of Children's Use of and Time Spent in Fast-Food and Full-Service Restaurants  

Science.gov (United States)

Objective: Identify parental and children's determinants of children's use of and time spent in fast-food (FF) and full-service (FS) restaurants. Design: Analysis of cross-sectional data. Setting: Parents were interviewed by phone; children were interviewed in their homes. Participants: Parents and children ages 9-11 or 13-15 from 312 families…

McIntosh, Alex; Kubena, Karen S.; Tolle, Glen; Dean, Wesley; Kim, Mi-Jeong; Jan, Jie-Sheng; Anding, Jenna

2011-01-01

346

Some Measurements of Fast Reactor Spectra by the Time-of-Flight Technique Using a Pulsed Neutron Source  

International Nuclear Information System (INIS)

The zero-energy fast reactor VERA is equipped with a pulsed neutron source and a 50-m neutron flight path and these facilities have been used for time-of-flight neutron spectrometry in the energy range 100 eV to 50 keV. The results are discussed and are compared with calculated values. (author)

1965-10-01

347

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

1983-12-05

348

From Zero to Sixty: Calibrating Real-Time Responses  

Science.gov (United States)

Recent advances in data recording technology have given researchers new ways of collecting on-line and continuous data for analyzing input-output systems. For example, continuous response digital interfaces are increasingly used in psychophysics. The statistical problem related to these input-output systems reduces to linking time-varying…

Koulis, Theodoro; Ramsay, James O.; Levitin, Daniel J.

2008-01-01

349

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

350

Liquid-metal fast breeder reactor intermediate heat exchanger transient modeling for faster than real-time analysis  

International Nuclear Information System (INIS)

A method was developed for faster than real-time liquid-metal fast breeder reactor intermediate heat exchanger (IHX) analysis for purposes of continuous on-line data validation, plant state verification, and fault identification. The basic feature of this method is the utilization of spatial nodes whose sizes vary with time. The use of time-variant node sizes leads to adequately accurate solutions with a few nodes and at short computation times. Applications of this methodology to reference IHX problems with the IBM 3033 machine showed that the computation time for steady-state analysis was --6 ms

1987-01-01

351

Fast, high peak capacity separations in gas chromatography-time-of-flight mass spectrometry.  

Science.gov (United States)

Peak capacity production (i.e., peak capacity per separation run time) is substantially improved for gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) and applied to the fast separation of complex samples. The increase in peak capacity production is achieved by selecting appropriate experimental conditions based on theoretical modeling of on-column band broadening, and by reducing the injection pulse width. Modeling to estimate the on-column band broadening from experimental parameters provided insight for the potential of achieving GC separations in the absence of off-column band broadening, i.e., the additional band broadening not due to the on-column separation process. To optimize GC-TOFMS separations collected with a commercial instrumental platform, off-column band broadening from injection and detection needed to be significantly reduced. Specifically for injection, a commercially available thermal modulator is adapted and applied (referred to herein as thermal injection) to provide a narrow injection pulse, while the TOFMS provided a data collection rate of 500 Hz, initially averaged to 100 Hz for data storage. The use of long, relatively narrow open tubular capillary columns and a 30 °C/min programming rate were explored for GC-TOFMS, specifically a 20 m, 100 ?m inner diameter (i.d.) capillary column with a 0.4 ?m film thickness to benefit column capacity, operated slightly below the optimal average linear gas velocity (at ~2 mL/min, due to the flow rate constraint of the TOFMS). Standard autoinjection with a 1:100 split resulted in an average peak width of ~1.2 s, hence a peak capacity production of 50 peaks/min. Metabolites in the headspace of urine were sampled by solid-phase microextraction (SPME), followed by thermal injection and a ~7 min GC separation (with a ~6 min separation time window), producing ~660 ms peak widths on average, resulting in a total peak capacity of ~550 peaks (at unit resolution) and a peak capacity production of ~90 peaks/min (~2-fold improvement relative to standard autoinjection with the 1:100 split). This total peak capacity production achieved is equivalent to, or greater than, that currently utilized in metabolomics studies using GC/MS, but with much slower separations, on the order of 40 to 60 min, corresponding to a 5-fold or greater GC/MS analysis throughput rate. PMID:22448931

Wilson, Ryan B; Hoggard, Jamin C; Synovec, Robert E

2012-05-01

352

Cubic response functions in time-dependent density functional theory.  

Science.gov (United States)

We present density-functional theory for time-dependent response functions up to and including cubic response. The working expressions are derived from an explicit exponential parametrization of the density operator and the Ehrenfest principle, alternatively, the quasienergy ansatz. While the theory retains the adiabatic approximation, implying that the time-dependency of the functional is obtained only implicitly-through the time dependence of the density itself rather than through the form of the exchange-correlation functionals-it generalizes previous time-dependent implementations in that arbitrary functionals can be chosen for the perturbed densities (energy derivatives or response functions). In particular, general density functionals beyond the local density approximation can be applied, such as hybrid functionals with exchange correlation at the generalized-gradient approximation level and fractional exact Hartree-Fock exchange. With our implementation the response of the density can always be obtained using the stated density functional, or optionally different functionals can be applied for the unperturbed and perturbed densities, even different functionals for different response order. As illustration we explore the use of various combinations of functionals for applications of nonlinear optical hyperpolarizabilities of a few centrosymmetric systems; molecular nitrogen, benzene, and the C(60) fullerene. Considering that vibrational, solvent, and local field factors effects are left out, we find in general that very good experimental agreement can be obtained for the second dynamic hyperpolarizability of these systems. It is shown that a treatment of the response of the density beyond the local density approximation gives a significant effect. The use of different functional combinations are motivated and discussed, and it is concluded that the choice of higher order kernels can be of similar importance as the choice of the potential which governs the Kohn-Sham orbitals. PMID:15740310

Jansik, Branislav; Sa?ek, Pawe?; Jonsson, Dan; Vahtras, Olav; Agren, Hans

2005-02-01

353

Statistical Tests of Conditional Independence between Responses and/or Response Times on Test Items  

Science.gov (United States)

Three plausible assumptions of conditional independence in a hierarchical model for responses and response times on test items are identified. For each of the assumptions, a Lagrange multiplier test of the null hypothesis of conditional independence against a parametric alternative is derived. The tests have closed-form statistics that are easy to…

van der Linden, Wim J.; Glas, Cees A. W.

2010-01-01

354

Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors  

Science.gov (United States)

Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

355

Fast time-resolved X-ray diffraction for studying laser T-jump-induced phase transitions  

International Nuclear Information System (INIS)

Phase transitions of phospholipid/water systems, triggered by a short 1-2 ms infrared laser heat pulse (Er-laser, wavelength: 1.5 ?m, energy 1-2 J), were studied by recording their real time X-ray powder diffraction patterns at a time resolution down to 0.5 ms using synchrotron radiation. Theoretical calculations of the temperature (T) profile show that the thermal gradient within the heated region of the aqueous sample is less than 2deg C and that the influence of temporal heat diffusion can be neglected on the time scale of these experiments, i.e. ?5 s. With this technique, combining the fast heating source with a fast X-ray detection system, it is possible to study the molecular spatial rearrangements and to evaluate the kinetics of thermotropic phase transitions of phospholipids in the millisecond time range. (orig.)

1990-05-20

356

Short-time T2-weighted MR imaging of the brain: Clinical evaluation of the hybrid fast-scan technique  

International Nuclear Information System (INIS)

The hybrid fast-scan technique (HFST) is designed to achieve acceptably short imaging times while maintaining T2 weighting as well as sufficient spatial and contrast resolution. The authors studied 20 patients with infarcts, primary tumors, metastatic tumors, or demyelinating disease of the brain, examining each prospectively with the HFST (imaging time, 4.3. minutes) as well as the standard two-dimensional Fourier transform method (imaging time 17.1 minutes). The two methods had equivalent accuracy. The HFST method, allowed fast data acquisition while maintaining the high T2 contrast necessary for lesion detection. It provided images with adequate T2 weighting in one-fourth the normal imaging time, with no loss in diagnostic accuracy

1986-12-05

357

Destruction of hazardous air pollutants using a fast rise time pulsed corona reactor  

Energy Technology Data Exchange (ETDEWEB)

Increasingly stringent environmental regulation imposed on both the military and civilian sectors has created a growing demand for alternative abatement methods for a variety of hazardous compounds. One alternative, the nonthermal plasma, shows promise of providing an efficient means for the destruction of dilute concentrations of hazardous air pollutants. The Dahlgren Laboratory of the Naval Surface Warfare Center has extensively investigated one type of nonthermal plasma discharge, the pulsed corona reactor, for the destruction of volatile organic compounds and chemical warfare agents. In this reactor, a fast rise time ({approximately}10ns), short duration ({lt}100ns), high-voltage pulse is repetitively delivered to a wire-cylinder electrode geometry, thereby producing a multitude of streamer discharges along its length. The resulting nonthermal plasma contains highly reactive chemical radicals which can interact with and destroy the hazardous molecules entrained in the ambient atmosphere flowing through the reactor volume. Increased electrical efficiency was obtained using a combination of high efficiency constant-current capacitor-charging, high repetition-rate spark gap switching, and resonant energy transfer to the reactor. Promising results have been obtained for toluene, methylene chloride, and dichlorodifluoromethane in air at concentrations of a few hundred parts per million. The device has been operated at voltages up to 30 kV, pulse repetition rates up to 1.4 kHz, and flow rates up to 60 scr(l)/min. Detailed electrical measurements have been made to properly characterize the electrical properties of the pulsed corona reactor and to validate subsequent improvements in the reactor energy efficiency. {copyright} {ital 1998 American Institute of Physics.}

Korzekwa, R.A. [Los Alamos National Laboratory, Los Alamos, New Mexico87545-1663 (United States); Grothaus, M.G. [Southwest Research Institute, 6220 Culebra Road, P.O. Drawer 28510, San Antonio, Texas78228-0510 (United States); Hutcherson, R.K. [OSRAM Sylvania, Inc., 71 Cherry Hill Drive, Beverly, Massachusetts 01915 (United States); Roush, R.A. [Federal Bureau of Investigation, Engineering Research Facility, MS EST-5, Building 27958-A, Quantico, Virginia22135 (United States); Brown, R. [Naval Surface Warfare Center, Dahlgren, Virginia22448-5100 (United States)

1998-04-01

358

Association of consecutive Pi2-Ps6 band pulsations with earthward fast flows in the plasma sheet in response to IMF variations  

Science.gov (United States)

11 March 2009, the H component had four consecutive bay-like variations accompanied by positive and negative deflections in the D component across the Atlantic like those affected by the substorm current wedge formation. A train of pulsations with a frequency range 2-10 mHz (referred to as Pi2-Ps6 band), sensed by Time History of Events and Macroscale Interactions during Substorms (THEMIS)/Canadian Array for Real-time Investigations of Magnetic Activity (CARISMA) magnetometers, had clearly three consecutive Pi2s followed by a Ps6 at low latitudes, but first Pi2 and then Ps6 at high latitudes mixed with large-amplitude Ps6 at midlatitudes. The geostationary orbit magnetometers sensed similar magnetic perturbations. THEMIS probes first observed earthward fast flows, magnetic dipolarizations, and modulated energetic particle fluxes at ~ XGSM -9.2 RE, then at ~ XGSM -7.5 RE for Pi2 and at ~ XGSM -18.0 RE only for Ps6. They appeared during a very quiet period for northward interplanetary magnetic field (IMF) with a clock angle variation of low to high and then low. The H spectrum shows two harmonic frequencies ~2-4 mHz and ~8-10 mHz but the D spectrum one dominant frequency ~2-4 mHz. Pi2 can result from a combination of fast magnetospheric and plasmaspheric cavity resonances and Ps6 from a fast magnetospheric cavity resonance. The surface waves at the interface separating braking earthward fast flows from the ambient plasma convection region could lead to large-amplitude Ps6 at midlatitudes. Hence, consecutive Pi2-Ps6 band pulsations can be associated with earthward fast flows in the plasma sheet, expectedly driven by magnetotail reconnection, respectively, in the near-Earth region and the distant Earth one in response to IMF variations as in the two-neutral-point model.

Cheng, Ching-Chang; Mann, Ian R.; Baumjohann, Wolfgang

2014-05-01

359

Exactly solvable model for the time response function of RPCs  

International Nuclear Information System (INIS)

The fluctuation theory for the growth of several avalanches is briefly summarized and extended to include the case of electronegative gas mixtures. Based on such physical picture, the intrinsic time response function of an RPC can be calculated in a closed form and its average and rms extracted from series representations. The corresponding timing resolution, expressed in units of 1/((?-?)vd), is a universal function of the mean number of 'effective' clusters n0 reduced by electron attachment: n0(1-?/?). A comparison to a few selected good-quality experimental data is attempted for the timing resolution of both 1-gap and 4-gaps RPCs, finding a reasonable agreement

2004-11-01

360

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

 
 
 
 
361

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory  

Science.gov (United States)

Physics related to fast ions in magnetically confined fusion plasmas is a very important issue, since these particles will play an important role in future burning plasmas. Indeed, they will act as primary heating source and will sustain the self-ignited condition. To measure the fast ion slowing-down times in a magnetohydrodynamic-quiescent plasmas in different scenarios, very short pulses of a deuterium neutral beam, so-called ``blip,'' with duration of about 5 ms were tangentially co-injected into a deuterium plasmas at the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak [L. W. Yan, Nucl. Fusion 51, 094016 (2011)]. The decay rate of 2.45 MeV D-D fusion neutrons produced by beam-plasma reactions following neutral beam termination was measured by means of a 235U fission chamber. Experimental results were compared with those predicted by a classical slowing-down model. These results show that the fast ions are well confined with a peaked profile and the ions are slowed down classically without significant loss in the HL-2A tokamak. Moreover, it has been observed that during electron cyclotron resonance heating the fast ions have a longer slowing-down time and the neutron emission rate decay time becomes longer.

Zhang, Y. P.; Isobe, M.; Liu, Yi; Yuan, G. L.; Yang, J. W.; Song, X. Y.; Song, X. M.; Cao, J. Y.; Lei, G. J.; Wei, H. L.; Li, Y. G.; Shi, Z. B.; Li, X.; Yan, L. W.; Yang, Q. W.; Duan, X. R.; HL-2A Team

2012-11-01

362

Measurements of the fast ion slowing-down times in the HL-2A tokamak and comparison to classical theory  

Energy Technology Data Exchange (ETDEWEB)

Physics related to fast ions in magnetically confined fusion plasmas is a very important issue, since these particles will play an important role in future burning plasmas. Indeed, they will act as primary heating source and will sustain the self-ignited condition. To measure the fast ion slowing-down times in a magnetohydrodynamic-quiescent plasmas in different scenarios, very short pulses of a deuterium neutral beam, so-called 'blip,' with duration of about 5 ms were tangentially co-injected into a deuterium plasmas at the HuanLiuqi-2A (commonly referred to as HL-2A) tokamak [L. W. Yan, Nucl. Fusion 51, 094016 (2011)]. The decay rate of 2.45 MeV D-D fusion neutrons produced by beam-plasma reactions following neutral beam termination was measured by means of a {sup 235}U fission chamber. Experimental results were compared with those predicted by a classical slowing-down model. These results show that the fast ions are well confined with a peaked profile and the ions are slowed down classically without significant loss in the HL-2A tokamak. Moreover, it has been observed that during electron cyclotron resonance heating the fast ions have a longer slowing-down time and the neutron emission rate decay time becomes longer.

Zhang, Y. P.; Liu, Yi; Yuan, G. L.; Yang, J. W.; Song, X. Y.; Song, X. M.; Cao, J. Y.; Lei, G. J.; Wei, H. L.; Li, Y. G.; Shi, Z. B.; Li, X.; Yan, L. W.; Yang, Q. W.; Duan, X. R. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Isobe, M. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Collaboration: HL-2A Team

2012-11-15

363

Equilibrium and response properties of the integrate-and-fire neuron in discrete time  

Directory of Open Access Journals (Sweden)

Full Text Available The integrate-and-fire neuron with exponential postsynaptic potentials is a frequently employed model to study neural networks. Simulations in discrete time still have highest performance at moderate numerical errors, which makes them first choice for long-term simulations of plastic networks. Here we extend the population density approach to investigate how the equilibrium and response properties of the leaky integrate-and-fire neuron are affected by time discretization. We present a novel analytical treatment of the boundary condition at threshold, taking both discretization of time and finite synaptic weights into account. We uncover an increased membrane potential density just below threshold as the decisive property that explains the deviations found between simulations and the classical diffusion approximation. Temporal discretization and finite synaptic weights both contribute to this effect. Our treatment improves the standard formula to calculate the neuron’s equilibrium firing rate. Direct solution of the Markov process describing the evolution of the membrane potential density confirms our analysis and yields a method to calculate the firing rate exactly. Knowing the shape of the membrane potential distribution near threshold enables us to devise the transient response properties of the neuron model to synaptic input. We find a pronounced non-linear fast response component that has not been described by the prevailing continuous time theory for Gaussian white noise input.

MoritzHelias

2010-01-01

364

Effects of training the coincidence-anticipation timing task on response time and activity in the cortical region.  

Science.gov (United States)

We examined the effects of training the coincidence-anticipation timing task on response time and activity in the cortical region. The task, which used a partially masked stimulus runway, required 12 participants to press a button at the time that they anticipated a moving visual target would arrive at the end of the runway. Training involved practicing the task a total of 10 times (once per day) over a 3-week period. Continuous electroencephalograms were recorded while performing the task before training and after training. The electroencephalograms were subjected to fast Fourier transform to obtain the power density in the beta bands. Peak amplitude and peak latency of event-related potentials were also determined. The results showed that, compared with before training, in the masked section of the task, the percentage of beta band activity was significantly increased in Brodmann's area 6 and significantly decreased in Brodmann's area 46 bilaterally after training. In addition, peak latency was significantly shorter in Brodmann's area 6 after training. These findings suggest that activation of Brodmann's area 6 in the masked section of the task after training might reflect the transfer from processing visual information of the moving target in the visible section of the task to predicting the target's movement in the masked section. In addition, the shortened peak latency in Brodmann's area 6 after training might reflect facilitation of information processing, which is why the mean absolute error was decreased after training. PMID:24513706

Koshizawa, Ryo; Mori, Akio; Oki, Kazuma; Takayose, Masaki; Minakawa, Nahoko Therese

2014-05-01

365

Classic dose-response and time postinoculation models for leptospira.  

Science.gov (United States)

Leptospirosis is a preeminent zoonotic disease concentrated in tropical areas, and prevalent in both industrialized and rural settings. Dose-response models were generated from 22 data sets reported in 10 different studies. All of the selected studies used rodent subjects, primarily hamsters, with the predominant endpoint as mortality with the challenge strain administered intraperitoneally. Dose-response models based on a single evaluation postinfection displayed median lethal dose (LD50 ) estimates that ranged between 1 and 10(7) leptospirae depending upon the strain's virulence and the period elapsed since the initial exposure inoculation. Twelve of the 22 data sets measured the number of affected subjects daily over an extended period, so dose-response models with time-dependent parameters were estimated. Pooling between data sets produced seven common dose-response models and one time-dependent model. These pooled common models had data sets with different test subject hosts, and between disparate leptospiral strains tested on identical hosts. Comparative modeling was done with parallel tests to test the effects of a single different variable of either strain or test host and quantify the difference by calculating a dose multiplication factor. Statistical pooling implies that the mechanistic processes of leptospirosis can be represented by the same dose-response model for different experimental infection tests even though they may involve different host species, routes, and leptospiral strains, although the cause of this pathophysiological phenomenon has not yet been identified. PMID:24117870

Watanabe, Toru; Teske, Sondra S; Haas, Charles N

2014-03-01

366

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

367

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

International Nuclear Information System (INIS)

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 ? ? ? 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 ?'-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)

1997-01-01

368

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

369

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

370

A fast time-amplitude converter for low-energy physics measurements  

International Nuclear Information System (INIS)

This converter permits the measurement of neutron times of flight up to 150 ns. The saw-tooth generator employs a 6BN6 tube fed at low voltage. There are two main points to be noted. The first relates to the tube itself: the influence of the inter-electrode capacitances increases with the speed of the signals, so that it was necessary to provide efficient neutrodyning of the No. 3 grid anode capacitance, which disturbed the conversion. The other point is that the exactness of the time definition is limited owing to the amplitude spectrum of the signals from the photomultiplier which makes it difficult to determine the instant that corresponds to a pulse. To reduce this difficulty, the authors took a selection of measurements. The performance of the equipment was checked under simulated normal working conditions: the two instants are defined by two distinct detection channels, each having a photomultiplier and a scintillator. The half-height width of a peak corresponding to a fixed delay gives the time definition; values were obtained from 0.8 to 1.3 ns for the half-height width of the peak, depending on the setting, and the drift for 15 hours of operation remained less than 0.3 % of the range. The linearity of the response curve as measured by accident coincidence is better than ± 0.3 % between 5 and 95 % of the measured area. (author)

1962-04-01

371

Fast time-correlated single-photon counting fluorescence lifetime acquisition using a 100 MHz semiconductor excitation source  

International Nuclear Information System (INIS)

The fast and efficient collection of time-resolved fluorescence decay data is shown using a high repetition rate semiconductor laser excitation source optimally matched to low dead-time counting electronics. The 100 MHz repetition rate allows a measurement range of 10 ns without re-excitation of the sample. Rapid acquisition of time-resolved fluorescence data is essential for microscopy applications, such as fluorescence lifetime imaging. With this in mind we measured a representative dye (lifetime 376 ps) to determine the fastest collection time for a single exponential decay. Other dyes were also used with lifetimes ranging from ?90 ps to 4 ns. (technical design note)

2011-06-01

372

Fast Mode Decision on H.264/AVC Baseline Profile for real-time performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper a new fast mode decision (FMD) algorithm is proposed for the recent H.264/AVC video coding standard, aiming to reduce its computational load without loosing coding efficiency. This algorithm identifies redundancy and selects the minimum sub-set of modes for each macroblock (MB) required to provide high rate-distortion (RD) efficiency. It is based on a fast analysis of the histogram of the difference image between frames which classifies the areas of each frame as active or non-a...

Nieto Doncel, Marcos; Salgado A?lvarez Sotomayor, Luis; Cabrera Quesada, Julian; Garci?a Santos, Narciso

2008-01-01

373

Fast magnetic response in gigahertz-band for columnar-structured Fe nanoparticle assembly  

Science.gov (United States)

High density Fe-based ferromagnetic nanoparticle (NP) assembly is expected to have unique magnetic properties, such as superferromagnetism and super-spin-glass, different from magnetically isolated NP systems due to strong dipole interactions among the NPs. A high dipole interaction field, Hdip, of ˜3.5 kOe can result in a high effective internal field to the magnetic moment of the NP, expecting for ultra-fast magnetic response, that is, a high magnetic resonance frequency, fr, of ˜10 GHz. However, for a simply molded Fe NP assembly, a low fr was observed due to inhomogeneous distribution of the internal field, implying the necessity of a unidirectional state of Hdip for higher fr. In this study, we fabricated a columnar Fe NP assembly for realizing the unidirectional state of Hdip by applying our uniquely developed external field-induced agglomeration method for monodispersed Fe NPs (13 nm in average size) as a function of the field (0-30 kOe) and volume fraction of the Fe NPs (0.5%-51%) in a polymer matrix with dimensions of 4 mm × 4 mm × 0.7 mmt. A columnar-structured Fe NP assembly was successfully achieved along an in-plane direction (defined as the x-axis) under optimized conditions. From static magnetization curves, induced uniaxial magnetic anisotropy was observed according to the shape of the columnar structure of the Fe NP assembly, where easy and hard axes of magnetization were realized along the parallel (x-axis) and normal directions (in-plane y-axis and z-axis in the thickness direction) to the external field during the process, respectively. Interestingly, this fabricated columnar-structured Fe NP assembly exhibited very high fr in the range from 3 to 11 GHz judging from the complex susceptibility spectra obtained. The fr values were well-scaled by a modified Snoek's-limit-law using demagnetization factors quantitatively estimated from the static magnetization curves. Thus, shape-induced anisotropy originating from the unidirectional state of Hdip in the columnar structure of the Fe NP assembly plays an important role for high frequency magnetic response in the GHz-band.

Ogawa, T.; Kura, H.; Tate, R.; Oikawa, T.; Hata, K.

2014-05-01

374

EVALUATION OF A FAST-RESPONSE URBAN WIND MODEL - COMPARISON TO SINGLE-BUILDING WIND TUNNEL DATA  

International Nuclear Information System (INIS)

Prediction of the 3-dimensional flow field around buildings and other obstacles is important for a number of applications, including urban air quality studies, the tracking of plumes from accidental releases of toxic air contaminants, indoor/outdoor air pollution problems, and thermal comfort assessments. Various types of computational fluid dynamics (CFD) models have been used for determining the flow fields around buildings (e.g., Reisner et al., 1998; Eichhorn et al., 1988). Comparisons to measurements show that these models work reasonably well for the most part (e.g., Ehrhard et al., 2 ; Johnson and Hunter, 1998; Murakami, 1997). However, CFD models are computationally intensive and for some applications turn-around time is of the essence. For example, planning and assessment studies in which hundreds of cases must be analyzed or emergency response scenarios in which plume transport must be computed quickly. Several fast-response dispersion models of varying levels of fidelity have been developed to explicitly account for the effects of a single building or groups of buildings (e.g., UDM - Hall et al. (2000), NRC-Ramsdell and Fosmire (1995), CBP-3 - Yamartino and Wiegand (1986), APRAC - Daerdt et al. (1973)). Although a few of these models include the Hotchkiss and Harlow (1973) analytical solution for potential flow in a notch to describe the velocity field within an urban canyon, in general, these models do not explicitly compute the velocity field around groups of buildings. The EPA PRIME model (Schulman et al., 2000) has been empirically derived to provide streamlines around a single isolated building

2001-01-01

375

Effects of thermodynamics parameters of steam generator on the response behavior of leak detection system for liquid metal-cooled fast breeder reactor  

International Nuclear Information System (INIS)

The one dimension mathematics model is established for the diffusion of sodium-water reaction products in steam generator (SG) and leak detection system (LDS) for liquid metal-cooled fast breeder reactor. The effects of sodium temperature and flowrate of SG and LDS are analyzed and the useful results are obtained from numerical calculations and experiments in a sodium loop. The results show that increasing the sodium flowrate of SG and LDS, the response time of LDS is decreased, but the sensitivity is lowered. The effect of sodium temperature of SG on the response time of LDS is less than that of sodium flowrate in SD, however, it can make the sensitivity of LDS higher when the sodium temperature is raised

2001-01-01

376

Consumer responses to time varying prices for electricity  

International Nuclear Information System (INIS)

We report new experimental evidence of the household response to weekday differentials in peak and off-peak electricity prices. The data come from Auckland, New Zealand, where peak residential electricity consumption occurs in winter for heating. Peak/off-peak price differentials ranged over four randomly selected groups from 1.0 to 3.5. On average, there was no response except in winter. In winter, participant households reduced electricity consumption by at least 10%, took advantage of lower off-peak prices but did not respond to the peak price differentials. Response varied with house and household size, time spent away from home, and whether water was heated with electricity. - Highlights: ? Seasonal effects in winter. ? High conservation effect from information. ? Higher peak prices no effect on peak use. ? Low off-peak prices encourage less conservation off-peak.

2012-10-01

377

Studies of fast-ion transport induced by energetic particle modes using fast-particle diagnostics with high time resolution in CHS  

Science.gov (United States)

The purpose of this work is to reveal the effects of the energetic particle mode (EPM) on fast-ion transport and consequent fast-ion loss in the compact helical system (CHS). For this purpose, fast particle diagnostics capable of following fast events originating from the EPM (f CHS. Experiments show that the EPM excited by co-circulating fast ions in an outward-shifted configuration is identified as a mode of m/n = 3/2 and can enhance fast-ion loss when its magnetic fluctuation amplitude exceeds ~4 × 10-5 T at the magnetic probe position. The lost fast-ion probe (LIP) located at the outboard side of the torus indicates that bursting EPMs lead to periodically enhanced losses of co-going fast ions having smaller pitch angles in addition to losses of marginally co-passing fast ions. Coinciding with EPM bursts, the H? light detector viewing the peripheral region at the outboard side also shows large pulsed increases similar to that of the LIP whereas the detector viewing the peripheral region at the inboard side does not. This is also evidence that fast ions are expelled to the outboard side due to the EPM. The charge-exchange neutral particle analyser indicates that only fast ions whose energy is close to the beam injection energy Eb are strongly affected by EPM, suggesting in turn that observed EPMs are excited by fast ions having energy close to Eb.

Isobe, M.; Toi, K.; Matsushita, H.; Goto, K.; Suzuki, C.; Nagaoka, K.; Nakajima, N.; Yamamoto, S.; Murakami, S.; Shimizu, A.; Yoshimura, Y.; Akiyama, T.; Minami, T.; Nishiura, M.; Nishimura, S.; Darrow, D. S.; Spong, D. A.; Shinohara, K.; Sasao, M.; Matsuoka, K.; Okamura, S.; CHS Team

2006-10-01

378

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 all...

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

2009-01-01

379

Metabolomics reveals differences in postprandial responses to breads and fasting metabolic characteristics associated with postprandial insulin demand in postmenopausal women.  

Science.gov (United States)

Changes in serum metabolic profile after the intake of different food products (e.g., bread) can provide insight into their interaction with human metabolism. Postprandial metabolic responses were compared after the intake of refined wheat (RWB), whole-meal rye (WRB), and refined rye (RRB) breads. In addition, associations between the metabolic profile in fasting serum and the postprandial concentration of insulin in response to different breads were investigated. Nineteen postmenopausal women with normal fasting glucose and normal glucose tolerance participated in a randomized, controlled, crossover meal study. The test breads, RWB (control), RRB, and WRB, providing 50 g of available carbohydrate, were each served as a single meal. The postprandial metabolic profile was measured using nuclear magnetic resonance and targeted LC-mass spectrometry and was compared between different breads using ANOVA and multivariate models. Eight amino acids had a significant treatment effect (P personalized nutrition. PMID:24717363

Moazzami, Ali A; Shrestha, Aahana; Morrison, David A; Poutanen, Kaisa; Mykkänen, Hannu

2014-06-01

380

Optimal time interval for induction of immunologic adaptive response  

International Nuclear Information System (INIS)

The optimal time interval between prior dose (D1) and challenge dose (D2) for the induction of immunologic adaptive response was investigated. Kunming mice were exposed to 75 mGy X-rays at a dose rate of 12.5 mGy/min. 3, 6, 12, 24 or 60 h after the prior irradiation the mice were challenged with a dose of 1.5 Gy at a dose rate of 0.33 Gy/min. 18h after D2, the mice were sacrificed for examination of immunological parameters. The results showed that with an interval of 6 h between D1 and D2, the adaptive response of the reaction of splenocytes to LPS was induced, and with an interval of 12 h the adaptive responses of spontaneous incorporation of 3H-TdR into thymocytes and the reaction of splenocytes to Con A and LPS were induced with 75 mGy prior irradiation. The data suggested that the optimal time intervals between D1 and D2 for the induction of immunologic adaptive response were 6 h and 12 h with a D1 of 75 mGy and a D2 of 1.5 Gy. The mechanism of immunologic adaptation following low dose radiation is discussed

1994-10-01

 
 
 
 
381

Time to peak serum antibody response to influenza vaccine.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The time to the appearance of a peak serum antibody response to influenza virus vaccine is not clearly defined. We compared the most commonly used time intervals described in the literature--4 and 6 weeks after vaccination. We studied 118 elderly patients from three different geographic sites. The 1992 to 1993 trivalent inactivated influenza virus vaccine containing influenza virus A/Beijing/353/89 (H3N2), influenza virus A/Texas/36/91 (H1N1), and influenza virus B/Panama/45/90 was used. No s...

1995-01-01

382

SOA Does Not Reveal the Absolute Time Course of Cognitive Processing in Fast Priming Experiments  

Science.gov (United States)

Applying Bloch's law to visual word recognition research, both exposure duration of the prime and its luminance determine the prime's overall energy, and consequently determine the size of the priming effect. Nevertheless, experimenters using fast-priming paradigms traditionally focus only on the SOA between prime and target to reflect the…

Tzur, Boaz; Frost, Ram

2007-01-01

383

In-situ response time testing of platinum resistance thermometers  

International Nuclear Information System (INIS)

Interim results are presented of Research Project 503-3, concerned with in-situ resistance temperature detector (RTD) time response verification. The report covers the theoretical bases, laboratory experimentation, and limited in-plant testing of three prospective methods. Sensors employed in this project represent those which are presently employed in safety-related applications in the field, namely Rosemount models 176KF, 177GY, and 104AFC

1977-01-01

384

Object Oriented Query Response Time for UML Models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays, the size of database of any business organization is increasing and many of the companies are shifted the old structured database into the object oriented database. Due to increase of size of database complexity of database is increasing therefore, it is necessary to optimize the object oriented query response time from the complex object oriented database. In the present paper, a real case study of Life Insurance Corporation of India is taken and sample object oriented database is ...

Vipin Saxena; Santosh Kumar

2012-01-01

385

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

2013-01-01

386

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.

Duc Thuan Vu

2013-05-01

387

Surface Response-based Behavioral Modeling of Accurate Digitizers a Case Study on a Fast Digital Integrator at CERN  

CERN Document Server

A statistical approach to behavioral modeling for assessing dynamic metrological performance during the concept design of accurate digitizers is proposed. A surface-response approach based on statistical experiment design is exploited for avoiding unrealistic hypothesis of linearity, optimizing simulation, exploring operating conditions systematically, as well as verifying identification and validation uncertainty. An actual case study on the dynamic metrological characterization of a Fast Digital Integrator for high-performance magnetic measurements at the European Organization for Nuclear Research (CERN) is presented.

Arpaia, P; Spiezia, G; Tiso, S

2007-01-01

388

Frequency analysis of the visual steady-state response measured with the fast optical signal in younger and older adults  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Relatively high frequency activity (>4 Hz) carries important information about the state of the brain or its response to high frequency events. The electroencephalogram (EEG) is commonly used to study these changes because it possesses high temporal resolution and a good signal-to-noise ratio. However, it provides limited spatial information. Non-invasive fast optical signals (FOS) have been proposed as a neuroimaging tool combining spatial and temporal resolution. Yet, this technique has not...

Tse, Chun-yu; Gordon, Brian A.; Fabiani, Monica; Gratton, Gabriele

2010-01-01

389

Fast and slow timescales in the tropical low-cloud response to increasing CO{sub 2} in two climate models  

Energy Technology Data Exchange (ETDEWEB)

To obtain physical insights into the response and feedback of low clouds (C{sub l}) to global warming, ensemble 4 x CO{sub 2} experiments were carried out with two climate models, the Model for Interdisciplinary Research on Climate (MIROC) versions 3.2 and 5. For quadrupling CO{sub 2}, tropical-mean C{sub l} decreases, and hence, acts as positive feedback in MIROC3, whereas it increases and serves as negative feedback in MIROC5. Three time scales of tropical-mean C{sub l} change were identified - an initial adjustment without change in the global-mean surface air temperature, a slow response emerging after 10-20 years, and a fast response in between. The two models share common features for the former two changes in which C{sub l} decreases. The slow response reflects the variability of C{sub l} associated with the El Nino-Southern Oscillation in the control integration, and may therefore be constrained by observations. However, the fast response is opposite in the two models and dominates the total response of C{sub l}. Its sign is determined by a subtle residual of the C{sub l} increase and decrease over the ascending and subsidence regions, respectively. The regional C{sub l} increase is consistent with a more frequent occurrence of a stable condition, and vice versa, as measured by lower-tropospheric stability (LTS). The above frequency change in LTS is similarly found in six other climate models despite a large difference in both the mean and the changes in the low-cloud fraction for a given LTS. This suggests that the response of the thermodynamic constraint for C{sub l} to increasing CO{sub 2} concentrations is a robust part of the climate change. (orig.)

Watanabe, Masahiro; Yoshimori, Masakazu; Kimoto, Masahide [The University of Tokyo, Atmosphere and Ocean Research Institute, Chiba (Japan); Shiogama, Hideo; Ogura, Tomoo; Yokohata, Tokuta [National Institute for Environmental Studies, Tsukuba (Japan); Okamoto, Hajime [Kyushu University, Research Institute for Applied Mechanics, Fukuoka (Japan); Emori, Seita [The University of Tokyo, Atmosphere and Ocean Research Institute, Chiba (Japan); National Institute for Environmental Studies, Tsukuba (Japan)

2012-10-15

390

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

391

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

392

Development of a very fast spectral response measurement system for analysis of hydrogenated amorphous silicon solar cells and modules  

International Nuclear Information System (INIS)

Highlights: ? Spectral response equipment for measuring a-Si:H solar cells in a few seconds. ? Equipment based on 16 LEDs with simultaneous illumination of the solar cell. ? The current generated by each LED is analyzed by a Fast Fourier Transform. ? Cheap equipment without lock-in technology for the current measurement. ? Measurement error vs. conventional measurement less than 1% in Jsc. - Abstract: An important requirement for a very fast spectral response measurement system is the simultaneous illumination of the solar cell at multiple well defined wavelengths. Nowadays this can be done by means of light emitting diodes (LEDs) available for a multitude of wavelengths. For the purpose to measure the spectral response (SR) of amorphous silicon solar cells a detailed characterization of LEDs emitting in the wavelength range from 300 nm to 800 nm was performed. In the here developed equipment the LED illumination is modulated in the frequency range from 100 Hz to 200 Hz and the current generated by each LED is analyzed by a Fast Fourier Transform (FFT) to determine the current component corresponding to each wavelength. The equipment provides a signal to noise ratio of 2–4 orders of magnitude for individual wavelengths resulting in a precise measurement of the SR over the whole wavelength range. The difference of the short circuit current determined from the SR is less than 1% in comparison to a conventional system with monochromator.

2013-01-01

393

Fast Response, Vertically Oriented Graphene Nanosheet Electric Double Layer Capacitors Synthesized from C2H2.  

Science.gov (United States)

The growth and electrical characteristics of vertically oriented graphene nanosheets grown by radio frequency plasma-enhanced chemical vapor deposition from C2H2 feedstock on nickel substrates and used as electrodes in symmetric electric double layer capacitors (EDLC) are presented. The nanosheets exhibited 2.7 times faster growth rate and much greater specific capacitance for a given growth time than CH4 synthesized films. Raman spectra showed that the intensity ratio of the D band to G band versus temperature initially decreased to a minimum value of 0.45 at a growth temperature of 750 °C, but increased rapidly with further temperature increase (1.15 at 850 °C). The AC specific capacitance at 120 Hz of these EDLC devices increased in a linear fashion with growth temperature, up to 265 ?F/cm(2) (2 ?m high film, 850 °C with 10 min growth). These devices exhibited ultrafast frequency response: the frequency response at -45° phase angle reached over 20 kHz. Consistent with the increase in D band to G band ratio, the morphology of the films became less vertical, less crystalline, and disordered at substrate temperatures of 800 °C and above. This deterioration in morphology resulted in an increase in graphene surface area and defect density, which, in turn, contributed to the increased capacitance, as well as a slight decrease