WorldWideScience

Sample records for continuous implanted drift

  1. An Universal packaging technique for low-drift implantable pressure sensors.

    Science.gov (United States)

    Kim, Albert; Powell, Charles R; Ziaie, Babak

    2016-04-01

    Monitoring bodily pressures provide valuable diagnostic and prognostic information. In particular, long-term measurement through implantable sensors is highly desirable in situations where percutaneous access can be complicated or dangerous (e.g., intracranial pressure in hydrocephalic patients). In spite of decades of progress in the fabrication of miniature solid-state pressure sensors, sensor drift has so far severely limited their application in implantable systems. In this paper, we report on a universal packaging technique for reducing the sensor drift. The described method isolates the pressure sensor from a major source of drift, i.e., contact with the aqueous surrounding environment, by encasing the sensor in a silicone-filled medical-grade polyurethane balloon. In-vitro soak tests for 100 days using commercial micromachined piezoresistive pressure sensors demonstrate a stable operation with the output remaining within 1.8 cmH2O (1.3 mmHg) of a reference pressure transducer. Under similar test conditions, a non-isolated sensor fluctuates between 10 and 20 cmH2O (7.4-14.7 mmHg) of the reference, without ever settling to a stable operation regime. Implantation in Ossabow pigs demonstrate the robustness of the package and its in-vivo efficacy in reducing the baseline drift.

  2. A GENERIC PACKAGING TECHNIQUE USING FLUIDIC ISOLATION FOR LOW-DRIFT IMPLANTABLE PRESSURE SENSORS.

    Science.gov (United States)

    Kim, A; Powell, C R; Ziaie, B

    2015-06-01

    This paper reports on a generic packaging method for reducing drift in implantable pressure sensors. The described technique uses fluidic isolation by encasing the pressure sensor in a liquid-filled medical-grade polyurethane balloon; thus, isolating it from surrounding aqueous environment that is the major source of baseline drift. In-vitro tests using commercial micromachined piezoresistive pressure sensors show an average baseline drift of 0.006 cmH 2 O/day (0.13 mmHg/month) for over 100 days of saline soak test, as compared to 0.101 cmH 2 O/day (2.23 mmHg/month) for a non-fluidic-isolated one soaked for 18 days. To our knowledge, this is the lowest reported drift for an implantable pressure sensor.

  3. Spectroscopic measurements with a silicon drift detector having a continuous implanted drift cathode-voltage divider

    CERN Document Server

    Bonvicini, V; D'Acunto, L; Franck, D; Gregorio, A; Pihet, P; Rashevsky, A; Vacchi, A; Vinogradov, L I; Zampa, N

    2000-01-01

    A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2x130 mm sup 2) and the charge is collected by two anodes (butterfly-like detector). The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from sup 5 sup 5 Fe and sup 2 sup 4 sup 1 Am are presented.

  4. Continuously live image processor for drift chamber track segment triggering

    International Nuclear Information System (INIS)

    Berenyi, A.; Chen, H.K.; Dao, K.

    1999-01-01

    The first portion of the BaBar experiment Level 1 Drift Chamber Trigger pipeline is the Track Segment Finder (TSF). Using a novel method incorporating both occupancy and drift-time information, the TSF system continually searches for segments in the supercells of the full 7104-wire Drift Chamber hit image at 3.7 MHz. The TSF was constructed to operate in a potentially high beam-background environment while achieving high segment-finding efficiency, deadtime-free operation, a spatial resolution of 5 simulated physics events

  5. Drift vortices in continuous media

    International Nuclear Information System (INIS)

    Chernousenko, V.M.; Chernenko, I.V.; Chernyshenko, S.V.

    1989-01-01

    The work is devoted to investigation into the problems of large-scale cortex drift and generation in continuous media based on the solution of notably non-linear differential equations. Using the capability of the modern computer technique it is possible to consider a series of cases with regard to medium viscosity and its inhomogeneity and with regard to three-dimensional vortex nature. Based on the solutions obtained the large-scale steady-state vortex generation processes are considered. The results can be used when studying non-linear phenomena in plasma and processes of substance and energy transfer in non-equilibrium media. 16 refs.; 5 figs

  6. Implantable Nanosensors: Towards Continuous Physiologic Monitoring

    OpenAIRE

    Ruckh, Timothy T.; Clark', Heather A.

    2013-01-01

    Continuous physiologic monitoring would add greatly to both home and clinical medical treatment for chronic conditions. Implantable nanosensors are a promising platform for designing continuous monitoring systems. This feature reviews design considerations and current approaches towards such devices.

  7. Subgeometric Ergodicity Analysis of Continuous-Time Markov Chains under Random-Time State-Dependent Lyapunov Drift Conditions

    Directory of Open Access Journals (Sweden)

    Mokaedi V. Lekgari

    2014-01-01

    Full Text Available We investigate random-time state-dependent Foster-Lyapunov analysis on subgeometric rate ergodicity of continuous-time Markov chains (CTMCs. We are mainly concerned with making use of the available results on deterministic state-dependent drift conditions for CTMCs and on random-time state-dependent drift conditions for discrete-time Markov chains and transferring them to CTMCs.

  8. [Guided and computer-assisted implant surgery and prosthetic: The continuous digital workflow].

    Science.gov (United States)

    Pascual, D; Vaysse, J

    2016-02-01

    New continuous digital workflow protocols of guided and computer-assisted implant surgery improve accuracy of implant positioning. The design of the future prosthesis is based on the available prosthetic space, gingival height and occlusal relationship with the opposing and adjacent teeth. The implant position and length depend on volume, density and bone quality, gingival height, tooth-implant and implant-implant distances, implant parallelism, axis and type of the future prosthesis. The crown modeled on the software will therefore serve as a guide to the future implant axis and not the reverse. The guide is made by 3D printing. The software determines surgical protocol with the drilling sequences. The unitary or plural prosthesis, modeled on the software and built before surgery, is loaded directly after implant placing, if needed. These protocols allow for a full continuity of the digital workflow. The software provides the surgeon and the dental technician a total freedom for the prosthetic-surgery guide design and the position of the implants. The prosthetic project, occlusal and aesthetic, taking the bony and surgical constraints into account, is optimized. The implant surgery is simplified and becomes less "stressful" for the patient and the surgeon. Guided and computer-assisted surgery with continuous digital workflow is becoming the technique of choice to improve the accuracy and quality of implant rehabilitation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  9. P-type silicon drift detectors

    International Nuclear Information System (INIS)

    Walton, J.T.; Krieger, B.; Krofcheck, D.; O'Donnell, R.; Odyniec, G.; Partlan, M.D.; Wang, N.W.

    1995-06-01

    Preliminary results on 16 CM 2 , position-sensitive silicon drift detectors, fabricated for the first time on p-type silicon substrates, are presented. The detectors were designed, fabricated, and tested recently at LBL and show interesting properties which make them attractive for use in future physics experiments. A pulse count rate of approximately 8 x l0 6 s -1 is demonstrated by the p-type silicon drift detectors. This count rate estimate is derived by measuring simultaneous tracks produced by a laser and photolithographic mask collimator that generates double tracks separated by 50 μm to 1200 μm. A new method of using ion-implanted polysilicon to produce precise valued bias resistors on the silicon drift detectors is also discussed

  10. Evaluation of dual-tip micromanometers during 21-day implantation in goats

    Science.gov (United States)

    Reister, C. A.; Koenig, S. C.; Schaub, J. D.; Ewert, D. L.; Swope, R. D.; Latham, R. D.; Fanton, J. W.; Convertino, V. A. (Principal Investigator)

    1998-01-01

    Investigative research efforts using a cardiovascular model required the determination of central circulatory haemodynamic and arterial system parameters for the evaluation of cardiovascular performance. These calculations required continuous beat-to-beat measurement of pressure within the four chambers of the heart and great vessels. Sensitivity and offset drift, longevity, and sources of error for eight 3F dual-tipped micromanometers were determined during 21 days of implantation in goats. Subjects were instrumented with pairs of chronically implanted fluid-filled access catheters in the left and right ventricles, through which dual-tipped (test) micromanometers were chronically inserted and single-tip (standard) micromanometers were acutely inserted. Acutely inserted sensors were calibrated daily and measured pressures were compared in vivo to the chronically inserted sensors. Comparison of the pre- and post-gain calibration of the chronically inserted sensors showed a mean sensitivity drift of 1.0 +/- 0.4% (99% confidence, n = 9 sensors) and mean offset drift of 5.0 +/- 1.5 mmHg (99% confidence, n = 9 sensors). Potential sources of error for these drifts were identified, and included measurement system inaccuracies, temperature drift, hydrostatic column gradients, and dynamic pressure changes. Based upon these findings, we determined that these micromanometers may be chronically inserted in high-pressure chambers for up to 17 days with an acceptable error, but should be limited to acute (hours) insertions in low-pressure applications.

  11. A novel self-biased linear silicon drift detector

    International Nuclear Information System (INIS)

    Corsi, F.; Gramegna, G.; Marzocca, C.

    1999-01-01

    A novel linear silicon drift detector (SDD) is proposed in which the proper potential profile is established by the voltage drop along a unique p + cathode implanted across the surfaces. This p + implant, arranged in a zigzag shape, acts at the same time as voltage divider and field cathode and allows one to increase the sensitive area, improving also the uniformity of the thermal distribution and thus minimizing the fluctuation of the electron mobility on the sensitive zone of the SDD. The perturbations of the drift field due to the asymmetry of the strips constituting the zigzag cathode have been evaluated by solving analytically Poisson's equation for a simplified model of the structure. Three-dimensional numerical simulations have been carried out to prove the negligible amount of the perturbation and the effectiveness of the proposed structure. Based on this principle, a prototype has been manufactured at Canberra Semiconductor Company. Dynamic measurements of the time-of-flight of an injected charge prove that the linearity of the prototype and the drift uniformity in the anode direction are very high

  12. Continued Drift, but without the Acrimony

    DEFF Research Database (Denmark)

    Nielsen, Kristian L.

    2013-01-01

    If the measure of Barack Obama's success in mending US–European relations is whether the tone has improved, his presidency has been a great success. If the measure of success, however, is halting the drifting apart of policy preferences, the picture looks a lot less rosy. This article argues....... The Obama administration realises that, and by this more limited measure, it has succeeded brilliantly....

  13. 4H-SiC vertical double implanted metal–oxide–semiconductor drift region—energy aspects of its formation and analysis

    International Nuclear Information System (INIS)

    Alkhem, Abdel; Šašić, Rajko M; Ostojić, Stanko M; Lukić, Petar M

    2014-01-01

    A conventional vertical double implanted metal–oxide–semiconductor structure contains two n +  regions beneath two symmetrically posed source biases. These n +  regions are surrounded by a p-doped layer, which itself has an abrupt transition to the vertical drift region. Owing to the existence of these p-layers, the ‘drift’ region has varying cross sections: it is reduced going upward from the bottom (drain bias) to the top. Such a drift region is usually described either by a three piecewise model, which begins with constant cross section that at some point starts narrowing until at some other point it becomes reduced to the region between two p-regions, or by a two piecewise model, whose narrowing region starts right above the drain bias and finishes in the manner described before. The crucial geometrical parameters of the flow profile in the drift region, such as the slope of the cross-section reducing region and the length of the narrowest (accumulation) region are widely used but never determined, or even estimated, in the available literature. In this paper, the least-action principle has been utilized successfully in order to determine the exact values of these parameters and so make the existing models closed. The proof has also been provided, which shows that the three piecewise model described the flow profile better than a two piecewise model more adequately as long as it was permitted by the length of the entire drift region (the energy necessary to restore the specific value of drain current is smaller than for the three piecewise model). The two piecewise model can be accepted in practical calculations only for higher values of drain current far from a triode regime. (paper)

  14. Continuous PECS II block for postoperative analgesia in patients undergoing transapical transcatheter aortic valve implantation.

    Science.gov (United States)

    Shakuo, Tomoharu; Kakumoto, Shinichi; Kuribayashi, Junya; Oe, Katsunori; Seo, Katsuhiro

    2017-01-01

    It has been reported that PECS II block can alleviate postoperative pain following transapical transcatheter aortic valve implantation (TA-TAVI). However, the effectiveness of continuous PECS II block with catheterization has not yet been reported on the postoperative pain in patients undergoing TA-TAVI. We experienced two cases of TA-TAVI who received PECS II block with catheterization to manage postoperative pain. In the first case, a bolus injection for intraoperative pain and subsequent catheterization were performed before the implantation. However, the patient developed severe pain postoperatively in spite of the continuous block due to displacement of the catheter. In the second case, a bolus injection and the catheterization for the continuous block were performed before and after the implantation, respectively, which provided high-quality pain control. Continuous PECS II block may be useful to control perioperative pain associated with TA-TAVI. The insertion of the catheter after the implantation could be useful to avoid its displacement during the surgery.

  15. Characterising large area silicon drift detectors with MOS injectors

    International Nuclear Information System (INIS)

    Bonvicini, V.; Rashevsky, A.; Vacchi, A.

    1999-01-01

    In the framework of the INFN DSI project, the first prototypes of a large-area Silicon Drift Detector (SDD) have been designed and produced on 5'' diameter wafers of Neutron Transmutation Doped (NTD) silicon with a resistivity of 3000 Ω·cm. The detector is a 'butterfly' bi-directional structure with a drift length of 32 mm and the drifting charge is collected by two arrays of anodes having a pitch of 200 μm. The high-voltage divider is integrated on-board and is realised with p + implantations. For test and calibration purposes, the detector has a new type of MOS injector. The paper presents results obtained to injecting charge at the maximum drift distance (32mm) from the anodes by means of the MOS injecting structure, As front-end electronics, the authors have used a 32-channels low-noise bipolar VLSI circuit (OLA, Omni-purpose Low-noise Amplifer) specifically designed for silicon drift detectors. The uniformity of the drift time in different regions of the sensitive area and its dependence on the ambient temperature are studied

  16. Continuous Thoracic Sympathetic Ganglion Block in Complex Regional Pain Syndrome Patients with Spinal Cord Stimulation Implantation

    Directory of Open Access Journals (Sweden)

    EungDon Kim

    2016-01-01

    Full Text Available The sympathetic block is widely used for treating neuropathic pain such as complex regional pain syndrome (CRPS. However, single sympathetic block often provides only short-term effect. Moreover, frequent procedures for sympathetic block may increase the risk of complications. The use of epidural route may be limited by concern of infection in case of previous implantation of the spinal cord stimulation (SCS. In contrast, a continuous sympathetic block can be administered without such concerns. The continuous thoracic sympathetic block (TSGB has been used to treat the ischemic disease and other neuropathic conditions such as postherpetic neuralgia. We administered continuous thoracic sympathetic block using catheter in CRPS patients who underwent SCS implantations and achieved desirable outcomes. We believe a continuous sympathetic block is a considerable option before performing neurolysis or radiofrequency rhizotomy and even after SCS implantation.

  17. Continuously Operating Biosensor and Its Integration into a Hermetically Sealed Medical Implant

    Directory of Open Access Journals (Sweden)

    Mario Birkholz

    2016-10-01

    Full Text Available An integration concept for an implantable biosensor for the continuous monitoring of blood sugar levels is presented. The system architecture is based on technical modules used in cardiovascular implants in order to minimize legal certification efforts for its perspective usage in medical applications. The sensor chip operates via the principle of affinity viscometry, which is realized by a fully embedded biomedical microelectromechanical systems (BioMEMS prepared in 0.25-µm complementary metal–oxide–semiconductor (CMOS/BiCMOS technology. Communication with a base station is established in the 402–405 MHz band used for medical implant communication services (MICS. The implant shall operate within the interstitial tissue, and the hermetical sealing of the electronic system against interaction with the body fluid is established using titanium housing. Only the sensor chip and the antenna are encapsulated in an epoxy header closely connected to the metallic housing. The study demonstrates that biosensor implants for the sensing of low-molecular-weight metabolites in the interstitial may successfully rely on components already established in cardiovascular implantology.

  18. The Drift Burst Hypothesis

    DEFF Research Database (Denmark)

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the continuous-time Itô semi-martingale model in such a way that the fundamental arbitrage-free property is preserved......, currencies and commodities. We find that the majority of identified drift bursts are accompanied by strong price reversals and these can therefore be regarded as “flash crashes” that span brief periods of severe market disruption without any material longer term price impacts....

  19. Evaluation on the movement of endosseous titanium implants under continuous orthodontic forces: an experimental study in the dog.

    Science.gov (United States)

    Hsieh, Yao-Dung; Su, Ching-Ming; Yang, Yi-Hsin; Fu, Earl; Chen, Hui-Lin; Kung, Suefang

    2008-06-01

    The purpose of this study was to evaluate the movement of pure titanium implants under different continuous forces in the edentulous alveolar ridge. Four pairs of titanium implants were inserted into the right maxillary and mandibular post-extraction edentulous ridge of the experimental dog. Three different levels of continuous force (100, 200, and 500 g) were loaded onto three pairs of adjacent implant abutments using a memory Ni-Ti coil spring for up to 6 months and the remaining two implant abutments as the control group received no force. The positions of implant abutments were observed and the distances between the implants abutment at the top, middle and base levels were measured at the 0th, 2nd, 3rd, 6th and 8th month of the follow-up period. There was no significant change in the distances between adjacent abutments loaded with 100 or 200 g continuous forces throughout the entire study period. However, significantly more movement of implant abutments was noted in the 500 g pair after the 3rd month of loading when compared with the 200 or the 100 g pair (both P < 0.001). This change further increased at the 6th month (P < 0.001, 0.01, respectively). Moreover, the difference in the measurements at the top, middle and base level indicated that the two adjacent implants moved in a tipping manner in the 500 g pair after 3 and 6 months of loading. The osseointegrated implants remained stable and rigid with a pulling force of 100 and 200 g after 6 months of loading. However, when the force reached 500 g, the implants moved in an inward-tipping pattern. The results suggested that endosseous titanium implants might not necessarily be rigid anchorages under all circumstances.

  20. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  1. A Fully Implantable, NFC Enabled, Continuous Interstitial Glucose Monitor

    OpenAIRE

    Anabtawi, Nijad; Freeman, Sabrina; Ferzli, Rony

    2016-01-01

    This work presents an integrated system-on-chip (SoC) that forms the core of a long-term, fully implantable, battery assisted, passive continuous glucose monitor. It integrates an amperometric glucose sensor interface, a near field communication (NFC) wireless front-end and a fully digital switched mode power management unit for supply regulation and on board battery charging. It uses 13.56 MHz (ISM) band to harvest energy and backscatter data to an NFC reader. System was implemented in 14nm ...

  2. Experimental Analysis of Temperature Differences During Implant Site Preparation: Continuous Drilling Technique Versus Intermittent Drilling Technique.

    Science.gov (United States)

    Di Fiore, Adolfo; Sivolella, Stefano; Stocco, Elena; Favero, Vittorio; Stellini, Edoardo

    2018-02-01

    Implant site preparation through drilling procedures may cause bone thermonecrosis. The aim of this in vitro study was to evaluate, using a thermal probe, overheating at implant sites during osteotomies through 2 different drilling methods (continuous drilling technique versus intermittent drilling technique) using irrigation at different temperatures. Five implant sites 13 mm in length were performed on 16 blocks (fresh bovine ribs), for a total of 80 implant sites. The PT-100 thermal probe was positioned 5 mm from each site. Two physiological refrigerant solutions were used: one at 23.7°C and one at 6.0°C. Four experimental groups were considered: group A (continuous drilling with physiological solution at 23.7°C), group B (intermittent drilling with physiological solution at 23.7°C), group C (continuous drilling with physiological solution at 6.0°C), and group D (intermittent drilling with physiological solution at 6.0°C). The Wilcoxon rank-sum test (2-tailed) was used to compare groups. While there was no difference between group A and group B (W = 86; P = .45), statistically significant differences were observed between experimental groups A and C (W = 0; P =.0001), B and D (W = 45; P =.0005), and C and D (W = 41; P = .003). Implant site preparation did not affect the overheating of the bone. Statistically significant differences were found with the refrigerant solutions. Using both irrigating solutions, bone temperature did not exceed 47°C.

  3. Autoregressive Modeling of Drift and Random Error to Characterize a Continuous Intravascular Glucose Monitoring Sensor.

    Science.gov (United States)

    Zhou, Tony; Dickson, Jennifer L; Geoffrey Chase, J

    2018-01-01

    Continuous glucose monitoring (CGM) devices have been effective in managing diabetes and offer potential benefits for use in the intensive care unit (ICU). Use of CGM devices in the ICU has been limited, primarily due to the higher point accuracy errors over currently used traditional intermittent blood glucose (BG) measures. General models of CGM errors, including drift and random errors, are lacking, but would enable better design of protocols to utilize these devices. This article presents an autoregressive (AR) based modeling method that separately characterizes the drift and random noise of the GlySure CGM sensor (GlySure Limited, Oxfordshire, UK). Clinical sensor data (n = 33) and reference measurements were used to generate 2 AR models to describe sensor drift and noise. These models were used to generate 100 Monte Carlo simulations based on reference blood glucose measurements. These were then compared to the original CGM clinical data using mean absolute relative difference (MARD) and a Trend Compass. The point accuracy MARD was very similar between simulated and clinical data (9.6% vs 9.9%). A Trend Compass was used to assess trend accuracy, and found simulated and clinical sensor profiles were similar (simulated trend index 11.4° vs clinical trend index 10.9°). The model and method accurately represents cohort sensor behavior over patients, providing a general modeling approach to any such sensor by separately characterizing each type of error that can arise in the data. Overall, it enables better protocol design based on accurate expected CGM sensor behavior, as well as enabling the analysis of what level of each type of sensor error would be necessary to obtain desired glycemic control safety and performance with a given protocol.

  4. A Fully Implantable, NFC Enabled, Continuous Interstitial Glucose Monitor.

    Science.gov (United States)

    Anabtawi, Nijad; Freeman, Sabrina; Ferzli, Rony

    2016-02-01

    This work presents an integrated system-on-chip (SoC) that forms the core of a long-term, fully implantable, battery assisted, passive continuous glucose monitor. It integrates an amperometric glucose sensor interface, a near field communication (NFC) wireless front-end and a fully digital switched mode power management unit for supply regulation and on board battery charging. It uses 13.56 MHz (ISM) band to harvest energy and backscatter data to an NFC reader. System was implemented in 14nm CMOS technology and validated with post layout simulations.

  5. Height drift correction in non-raster atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Travis R. [Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095 (United States); Ziegler, Dominik [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Brune, Christoph [Institute for Computational and Applied Mathematics, University of Münster (Germany); Chen, Alex [Statistical and Applied Mathematical Sciences Institute, Research Triangle Park, NC 27709 (United States); Farnham, Rodrigo; Huynh, Nen; Chang, Jen-Mei [Department of Mathematics and Statistics, California State University Long Beach, Long Beach, CA 90840 (United States); Bertozzi, Andrea L., E-mail: bertozzi@math.ucla.edu [Department of Mathematics, University of California Los Angeles, Los Angeles, CA 90095 (United States); Ashby, Paul D., E-mail: pdashby@lbl.gov [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2014-02-01

    We propose a novel method to detect and correct drift in non-raster scanning probe microscopy. In conventional raster scanning drift is usually corrected by subtracting a fitted polynomial from each scan line, but sample tilt or large topographic features can result in severe artifacts. Our method uses self-intersecting scan paths to distinguish drift from topographic features. Observing the height differences when passing the same position at different times enables the reconstruction of a continuous function of drift. We show that a small number of self-intersections is adequate for automatic and reliable drift correction. Additionally, we introduce a fitness function which provides a quantitative measure of drift correctability for any arbitrary scan shape. - Highlights: • We propose a novel height drift correction method for non-raster SPM. • Self-intersecting scans enable the distinction of drift from topographic features. • Unlike conventional techniques our method is unsupervised and tilt-invariant. • We introduce a fitness measure to quantify correctability for general scan paths.

  6. Collisional drift waves in the H-mode edge

    International Nuclear Information System (INIS)

    Sen, S.

    1994-01-01

    The stability of the collisional drift wave in a sheared slab geometry is found to be severely restricted at the H-mode edge plasma due to the very steep density gradient. However, a radially varying transverse velocity field is found to play the key role in stability. Velocity profiles usually found in the H-mode plasma stabilize drift waves. On the other hand, velocity profiles corresponding to the L-mode render collisional drift waves unstable even though the magnetic shear continues to play its stabilizing role. (author). 24 refs

  7. Non-linear coupling of drift modes in a quadrupole

    International Nuclear Information System (INIS)

    Elliott, J.A.; Sandeman, J.C.; Tessema, G.Y.

    1990-01-01

    We report continuing experimental studies of non-linear interactions of drift waves, with direct evidence of a growth saturation mechanism by transfer of energy to lower frequency modes. Wave launching experiments show that the decay rate of drift waves can be strongly amplitude dependent. (author) 9 refs., 5 figs

  8. Design Feature 7: Continuous Preclosure Ventilation

    International Nuclear Information System (INIS)

    A.T. Watkins

    1999-01-01

    This design feature (DF) is intended to evaluate the effects of continuous ventilation in the emplacement drifts during preclosure and how the effects, if any, compare to the Viability Assessment (VA) reference design for postclosure long term performance. This DF will be evaluated against a set of criteria provided by the License Application Design Selection (LADS) group. The VA reference design included a continuous ventilation airflow quantity of 0.1 m 3 /s in the emplacement drifts in the design of the repository subsurface facilities. The effects of this continuous ventilation during the preclosure was considered to have a negligible effect on postclosure performance and therefore is not included during postclosure in the assessment of the long term performance. This DF discusses the effects of continuous ventilation on the emplacement drift environment and surrounding rock conditions during preclosure for three increased airflow quantities. The three cases of continuous ventilation systems are: System A, 1.0 m 3 /s (Section 8), System B, 5.0 m 3 /s (Section 9), and System C, 10.0 m 3 /s (Section 10) in each emplacement drift split. An emplacement drift split is half total length of emplacement drift going from the east or west main to the exhaust main. The difference in each system is the quantity of airflow in the emplacement drifts

  9. Reducing Pesticide Drift

    Science.gov (United States)

    Provides information about pesticide spray drift, including problems associated with drift, managing risks from drift and the voluntary Drift Reduction Technology program that seeks to reduce spray drift through improved spray equipment design.

  10. Efficacy of Vancomycin-based Continuous Triple Antibiotic Irrigation in Immediate, Implant-based Breast Reconstruction

    Directory of Open Access Journals (Sweden)

    Lisa M. Hunsicker, MD, FACS

    2017-12-01

    Conclusions:. Continuous breast irrigation with a vancomycin-based triple antibiotic solution is a safe and effective accompaniment for immediate implant reconstruction. Use of intramuscular anesthetic injection for postoperative pain control allows the elastomeric infusion pump to be available for local tissue antibiotic irrigation.

  11. Computer simulations for intense continuous beam transport in electrostatic lens systems

    International Nuclear Information System (INIS)

    Zhao Xiaosong; Lv Jianqin

    2008-01-01

    A code LEADS based on the Lie algebraic analysis for the continuous beam dynamics with space charge effect in beam transport has been developed. The program is used for the simulations of axial-symmetric and unsymmetrical intense continuous beam in the channels including drift spaces, electrostatic lenses and DC electrostatic accelerating tubes. In order to get the accuracy required, all elements are divided into many small segments, and the electric field in the segments is regarded as uniform field, and the dividing points are treated as thin lenses. Iteration procedures are adopted in the program to obtain self-consistent solutions. The code can be used in the designs of low energy beam transport systems, electrostatic accelerators and ion implantation machines. (authors)

  12. Electron drift time in silicon drift detectors: A technique for high precision measurement of electron drift mobility

    International Nuclear Information System (INIS)

    Castoldi, A.; Rehak, P.

    1995-01-01

    This paper presents a precise absolute measurement of the drift velocity and mobility of electrons in high resistivity silicon at room temperature. The electron velocity is obtained from the differential measurement of the drift time of an electron cloud in a silicon drift detector. The main features of the transport scheme of this class of detectors are: the high uniformity of the electron motion, the transport of the signal electrons entirely contained in the high-purity bulk, the low noise timing due to the very small anode capacitance (typical value 100 fF), and the possibility to measure different drift distances, up to the wafer diameter, in the same semiconductor sample. These features make the silicon drift detector an optimal device for high precision measurements of carrier drift properties. The electron drift velocity and mobility in a 10 kΩ cm NTD n-type silicon wafer have been measured as a function of the electric field in the range of possible operation of a typical drift detector (167--633 V/cm). The electron ohmic mobility is found to be 1394 cm 2 /V s. The measurement precision is better than 1%. copyright 1995 American Institute of Physics

  13. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Dwayne C. Kicker

    2001-09-28

    A statistical description of the probable block sizes formed by fractures around the emplacement drifts has been developed for each of the lithologic units of the repository host horizon. A range of drift orientations with the drift azimuth varied in 15{sup o} increments has been considered in the static analysis. For the quasi-static seismic analysis, and the time-dependent and thermal effects analysis, two drift orientations have been considered: a drift azimuth of 105{sup o} and the current emplacement drift azimuth of 75{sup o}. The change in drift profile resulting from progressive deterioration of the emplacement drifts has been assessed both with and without backfill. Drift profiles have been determined for four different time increments, including static (i.e., upon excavation), 200 years, 2,000 years, and 10,000 years. The effect of seismic events on rock fall has been analyzed. Block size distributions and drift profiles have been determined for three seismic levels, including a 1,000-year event, a 5,000-year event, and a 10,000-year event. Data developed in this modeling and analysis activity have been entered into the TDMS (DTN: MO0109RDDAAMRR.003). The following conclusions have resulted from this drift degradation analysis: (1) The available fracture data are suitable for supporting a detailed key block analysis of the repository host horizon rock mass. The available data from the north-south Main Drift and the east-west Cross Drift provide a sufficient representative fracture sample of the repository emplacement drift horizon. However, the Tptpln fracture data are only available from a relatively small section of the Cross Drift, resulting in a smaller fracture sample size compared to the other lithologic units. This results in a lower degree of confidence that the key block data based on the Tptpln data set is actually representative of the overall Tptpln key block population. (2) The seismic effect on the rock fall size distribution for all events

  14. SOI detector with drift field due to majority carrier flow - an alternative to biasing in depletion

    Energy Technology Data Exchange (ETDEWEB)

    Trimpl, M.; Deptuch, G.; Yarema, R.; /Fermilab

    2010-11-01

    This paper reports on a SOI detector with drift field induced by the flow of majority carriers. It is proposed as an alternative method of detector biasing compared to standard depletion. N-drift rings in n-substrate are used at the front side of the detector to provide charge collecting field in depth as well as to improve the lateral charge collection. The concept was verified on a 2.5 x 2.5 mm{sup 2} large detector array with 20 {micro}m and 40 {micro}m pixel pitch fabricated in August 2009 using the OKI semiconductor process. First results, obtained with a radioactive source to demonstrate spatial resolution and spectroscopic performance of the detector for the two different pixel sizes will be shown and compared to results obtained with a standard depletion scheme. Two different diode designs, one using a standard p-implantation and one surrounded by an additional BPW implant will be compared as well.

  15. SOI detector with drift field due to majority carrier flow - an alternative to biasing in depletion

    International Nuclear Information System (INIS)

    Trimpl, M.; Deptuch, G.; Yarema, R.

    2010-01-01

    This paper reports on a SOI detector with drift field induced by the flow of majority carriers. It is proposed as an alternative method of detector biasing compared to standard depletion. N-drift rings in n-substrate are used at the front side of the detector to provide charge collecting field in depth as well as to improve the lateral charge collection. The concept was verified on a 2.5 x 2.5 mm 2 large detector array with 20 (micro)m and 40 (micro)m pixel pitch fabricated in August 2009 using the OKI semiconductor process. First results, obtained with a radioactive source to demonstrate spatial resolution and spectroscopic performance of the detector for the two different pixel sizes will be shown and compared to results obtained with a standard depletion scheme. Two different diode designs, one using a standard p-implantation and one surrounded by an additional BPW implant will be compared as well.

  16. Dike/Drift Interactions

    Energy Technology Data Exchange (ETDEWEB)

    E.S. Gaffney

    2003-10-08

    This report documents the model of events associated with a potential intrusion of magma from a volcanic dike into a drift or drifts in the Yucca Mountain Nuclear Waste Repository. The following topics are included in this report: (1) A discussion of dike propagation, which provides the basis for describing the path that a representative dike, or swarm of dikes, would follow during an event. (2) A discussion of magma flow, which evaluates the interaction at the junction of the propagating dike with the drift and the movement of magmatic products into and down drifts and, potentially, through a drift to the surface by way of access drift or a secondary dike opened up along the drift. (3) A discussion of gas flow and conductive cooling of a magma-filled drift, describing how an adjacent drift that has not been intersected by a dike could be affected by post-intrusion phenomena. Note that a gas flow analysis is also addressed in ''Igneous Intrusion Impacts on Waste Form and Waste Packages'' (BSC 2003 [DIRS 161810]), and those results are consistent with the results presented in this report.

  17. Dike/Drift Interactions

    International Nuclear Information System (INIS)

    E.S. Gaffney

    2003-01-01

    This report documents the model of events associated with a potential intrusion of magma from a volcanic dike into a drift or drifts in the Yucca Mountain Nuclear Waste Repository. The following topics are included in this report: (1) A discussion of dike propagation, which provides the basis for describing the path that a representative dike, or swarm of dikes, would follow during an event. (2) A discussion of magma flow, which evaluates the interaction at the junction of the propagating dike with the drift and the movement of magmatic products into and down drifts and, potentially, through a drift to the surface by way of access drift or a secondary dike opened up along the drift. (3) A discussion of gas flow and conductive cooling of a magma-filled drift, describing how an adjacent drift that has not been intersected by a dike could be affected by post-intrusion phenomena. Note that a gas flow analysis is also addressed in ''Igneous Intrusion Impacts on Waste Form and Waste Packages'' (BSC 2003 [DIRS 161810]), and those results are consistent with the results presented in this report

  18. Drift velocity monitoring of the CMS muon drift chambers

    CERN Document Server

    Sonnenschein, Lars

    2010-01-01

    The drift velocity in drift tubes of the CMS muon chambers is a key parameter for the muon track reconstruction and trigger. It needs to be monitored precisely in order to detect any deviation from its nominal value. A change in absolute pressure, a variation of the gas admixture or a contamination of the chamber gas by air affect the drift velocity. Furthermore the temperature and magnetic field influence its value. First data, taken with a dedicated Velocity Drift Chamber (VDC) built by RWTH Aachen IIIA are presented.

  19. Measurement of the positron-drift time relation of a high-pressure drift chamber

    International Nuclear Information System (INIS)

    Pruefert, W.

    1989-04-01

    As a test of its performance, the measurement of the drift time versus drift distance relation of a high pressure drift chamber using cosmic rays is described. Two multiwire proportional chambers, mounted above and below the detector, are used to define the track of the cosmic particle in the drift chamber. The drift chamber is read out by FADCs (Flash Analog to Digital Converter), and the drift time is determined from the FADC signals by the DOS- (Difference Of Samples) method. The measured drift time versus drift distance relation showed good agreement with the relation, which is expected from the spatial dependence of the electric field and the dependence of the drift velocity on this field. (orig.) [de

  20. Plasma source ion implantation

    International Nuclear Information System (INIS)

    Conrad, J.R.; Forest, C.

    1986-01-01

    The authors' technique allows the ion implantation to be performed directly within the ion source at higher currents without ion beam extraction and transport. The potential benefits include greatly increased production rates (factors of 10-1000) and the ability to implant non-planar targets without rastering or shadowing. The technique eliminates the ion extractor grid set, beam raster equipment, drift space and target manipulator equipment. The target to be implanted is placed directly within the plasma source and is biased to a large negative potential so that plasma ions gain energy as they accelerate through the potential drop across the sheath that forms at the plasma boundary. Because the sheath surrounds the target on all sides, all surfaces of the target are implanted without the necessity to raster the beam or to rotate the target. The authors have succeeded in implanting nitrogen ions in a silicon target to the depths and concentrations required for surface treatment of materials like stainless steel and titanium alloys. They have performed ESCA measurements of the penetration depth profile of a silicon target that was biased to 30 kV in a nitrogen discharge plasma. Nitrogen ions were implanted to a depth of 700A at a peak concentration of 30% atomic. The measured profile is quite similar to a previously obtained profile in titanium targets with conventional techniques

  1. Silicon Drift Detectors development for position sensing

    International Nuclear Information System (INIS)

    Castoldi, A.; Guazzoni, C.; Hartmann, R.; Strueder, L.

    2007-01-01

    Novel Silicon Drift Detectors (SDDs) with multi-linear architecture specifically intended for 2D position sensing and imaging applications are presented and their achievable spatial, energy and time resolution are discussed. The capability of providing a fast timing of the interaction with nanosecond time resolution is a new available feature that allows operating the drift detector in continuous readout mode for coincidence imaging applications either with an external trigger or in self-timing. The application of SDDs with multi-linear architecture to Compton electrons' tracking within a single silicon layer and the achieved experimental results will be discussed

  2. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    G.H. Nieder-Westermann

    2005-01-01

    The outputs from the drift degradation analysis support scientific analyses, models, and design calculations, including the following: (1) Abstraction of Drift Seepage; (2) Seismic Consequence Abstraction; (3) Structural Stability of a Drip Shield Under Quasi-Static Pressure; and (4) Drip Shield Structural Response to Rock Fall. This report has been developed in accordance with ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The drift degradation analysis includes the development and validation of rockfall models that approximate phenomenon associated with various components of rock mass behavior anticipated within the repository horizon. Two drift degradation rockfall models have been developed: the rockfall model for nonlithophysal rock and the rockfall model for lithophysal rock. These models reflect the two distinct types of tuffaceous rock at Yucca Mountain. The output of this modeling and analysis activity documents the expected drift deterioration for drifts constructed in accordance with the repository layout configuration (BSC 2004 [DIRS 172801])

  3. Drift velocity and pressure monitoring of the CMS muon drift chambers

    CERN Document Server

    Sonnenschein, Lars

    2011-01-01

    The drift velocity in drift tubes of the CMS muon chambers is a key parameter for the muon track reconstruction and trigger. It needs to be monitored precisely in order to detect any deviation from its nominal value. A change in absolute pressure, a variation of the gas admixture or a contamination of the chamber gas by air affect the drift velocity. Furthermore, the temperature and magnetic field influence its value. First data, taken with a dedicated Velocity Drift Chamber (VDC) built by RWTH Aachen IIIA are presented. Another important parameter to be monitored is the pressure inside the muon drift tube chambers. The differential pressure must not exceed a certain value and the absolute pressure has to be kept slightly above ambient pressure to prevent air from entering into the muon drift tube chambers in case of a leak. Latest drift velocity monitoring results are discussed.

  4. Design of a lead-glass drift calorimeter with MWPC detection

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; del Guerra, A.; Mulera, T.; Hirayama, H.; Nelson, W.R.

    1983-02-01

    A drift collection calorimeter having a combined radiator and field-shaping structure made of lead-glass tubing is described. A high-resistance metallic layer is formed by reduction of the lead oxide at the surface of the glass and forms a continuous voltage divider for drift-field shaping. The energy resolution of such a calorimeter is modeled, for several configurations, by the Monte Carlo technique

  5. Stokes drift

    Science.gov (United States)

    van den Bremer, T. S.; Breivik, Ø.

    2017-12-01

    During its periodic motion, a particle floating at the free surface of a water wave experiences a net drift velocity in the direction of wave propagation, known as the Stokes drift (Stokes 1847 Trans. Camb. Philos. Soc. 8, 441-455). More generally, the Stokes drift velocity is the difference between the average Lagrangian flow velocity of a fluid parcel and the average Eulerian flow velocity of the fluid. This paper reviews progress in fundamental and applied research on the induced mean flow associated with surface gravity waves since the first description of the Stokes drift, now 170 years ago. After briefly reviewing the fundamental physical processes, most of which have been established for decades, the review addresses progress in laboratory and field observations of the Stokes drift. Despite more than a century of experimental studies, laboratory studies of the mean circulation set up by waves in a laboratory flume remain somewhat contentious. In the field, rapid advances are expected due to increasingly small and cheap sensors and transmitters, making widespread use of small surface-following drifters possible. We also discuss remote sensing of the Stokes drift from high-frequency radar. Finally, the paper discusses the three main areas of application of the Stokes drift: in the coastal zone, in Eulerian models of the upper ocean layer and in the modelling of tracer transport, such as oil and plastic pollution. Future climate models will probably involve full coupling of ocean and atmosphere systems, in which the wave model provides consistent forcing on the ocean surface boundary layer. Together with the advent of new space-borne instruments that can measure surface Stokes drift, such models hold the promise of quantifying the impact of wave effects on the global atmosphere-ocean system and hopefully contribute to improved climate projections. This article is part of the theme issue 'Nonlinear water waves'.

  6. Drift velocity and pressure monitoring of the CMS muon drift chambers

    CERN Document Server

    Sonnenschein, Lars

    2010-01-01

    The drift velocity in drift tubes of the CMS muon chambers is a key parameter for the muon track reconstruction and trigger. It needs to be monitored precisely in order to detect any deviation from its nominal value. A change in absolute pressure, a variation of the gas admixture or a contamination of the chamber gas by air affect the drift velocity. Furthermore, the temperature and magnetic field influence its value. First data, taken with a dedicated Velocity Drift Chamber (VDC) built by RWTH Aachen IIIA are presented. Another important parameter to be monitored is the pressure inside the muon drift tube chambers because the drift velocity depends on it. Furthermore the differential pressure must not exceed a certain value and the absolute pressure has to be kept slightly above ambient pressure to prevent air from entering into the muon drift tube chambers in case of a leak. Latest pressure monitoring results are discussed.

  7. Dike/Drift Interactions

    Energy Technology Data Exchange (ETDEWEB)

    E. Gaffiney

    2004-11-23

    This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses of the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1).

  8. Dike/Drift Interactions

    International Nuclear Information System (INIS)

    Gaffiney, E.

    2004-01-01

    This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses of the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1)

  9. A detection system for charged-particle decay studies with a continuous-implantation method

    Energy Technology Data Exchange (ETDEWEB)

    Sun, L.J. [China Institute of Atomic Energy, Beijing 102413 (China); Xu, X.X., E-mail: xuxinxing@ciae.ac.cn [China Institute of Atomic Energy, Beijing 102413 (China); Lin, C.J., E-mail: cjlin@ciae.ac.cn [China Institute of Atomic Energy, Beijing 102413 (China); Wang, J.S. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fang, D.Q. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Z.H. [School of Physic and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wang, Y.T. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, J. [School of Physic and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Yang, L.; Ma, N.R. [China Institute of Atomic Energy, Beijing 102413 (China); Wang, K. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zang, H.L. [School of Physic and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wang, H.W.; Li, C.; Shi, C.Z.; Nie, M.W.; Li, X.F.; Li, H. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Ma, J.B.; Ma, P. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); and others

    2015-12-21

    A new detection system with high detection efficiency and low detection threshold has been developed for charged-particle decay studies, including β-delayed proton, α decay or direct proton emission from proton-rich nuclei. The performance was evaluated by using the β-delayed proton emitter {sup 24}Si produced by projectile fragmentation at the First Radioactive Ion Beam Line in Lanzhou. Under a continuous-beam mode, the isotopes of interest were implanted into two double-sided silicon strip detectors, where the subsequent decays were measured and correlated to the preceding implantations by using position and time information. The system allows us to measure protons with energies down to about 200 keV without obvious β background in the proton spectrum. Further application of the detection system can be extended to the measurements of β-delayed proton decay and the direct proton emission of more exotic proton-rich nuclei.

  10. Dimethyl ether as a drift-chamber gas

    International Nuclear Information System (INIS)

    Bari, G.; Basile, M.; Bonvicini, G.; Cara Romeo, G.; Casaccia, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; D'Ali, G.; Del Papa, C.; Focardi, S.; Iacobucci, G.; Maccarrone, G.; Massam, T.; Motta, F.; Nania, R.; Palmonari, F.; Prisco, G.; Sartorelli, G.; Susinno, G.; Votano, L.; Zichichi, A.; Istituto Nazionale di Fisica Nucleare, Bologna; European Organization for Nuclear Research, Geneva; Istituto Nazionale di Fisica Nucleare, Frascati; Michigan Univ., Ann Arbor; Palermo Univ.

    1986-01-01

    We have continued the testing of dimethyl ether as a drift-chamber gas in order to improve the understanding of its properties. In particular, we report on measurement accuracy, on systematic effects, and some preliminary data on the ageing of a detector filled with dimethyl ether. (orig.)

  11. Chronically implanted pressure sensors: challenges and state of the field.

    Science.gov (United States)

    Yu, Lawrence; Kim, Brian J; Meng, Ellis

    2014-10-31

    Several conditions and diseases are linked to the elevation or depression of internal pressures from a healthy, normal range, motivating the need for chronic implantable pressure sensors. A simple implantable pressure transduction system consists of a pressure-sensing element with a method to transmit the data to an external unit. The biological environment presents a host of engineering issues that must be considered for long term monitoring. Therefore, the design of such systems must carefully consider interactions between the implanted system and the body, including biocompatibility, surgical placement, and patient comfort. Here we review research developments on implantable sensors for chronic pressure monitoring within the body, focusing on general design requirements for implantable pressure sensors as well as specifications for different medical applications. We also discuss recent efforts to address biocompatibility, efficient telemetry, and drift management, and explore emerging trends.

  12. Drift-Scale Radionuclide Transport

    International Nuclear Information System (INIS)

    Houseworth, J.

    2004-01-01

    The purpose of this model report is to document the drift scale radionuclide transport model, taking into account the effects of emplacement drifts on flow and transport in the vicinity of the drift, which are not captured in the mountain-scale unsaturated zone (UZ) flow and transport models ''UZ Flow Models and Submodels'' (BSC 2004 [DIRS 169861]), ''Radionuclide Transport Models Under Ambient Conditions'' (BSC 2004 [DIRS 164500]), and ''Particle Tracking Model and Abstraction of Transport Process'' (BSC 2004 [DIRS 170041]). The drift scale radionuclide transport model is intended to be used as an alternative model for comparison with the engineered barrier system (EBS) radionuclide transport model ''EBS Radionuclide Transport Abstraction'' (BSC 2004 [DIRS 169868]). For that purpose, two alternative models have been developed for drift-scale radionuclide transport. One of the alternative models is a dual continuum flow and transport model called the drift shadow model. The effects of variations in the flow field and fracture-matrix interaction in the vicinity of a waste emplacement drift are investigated through sensitivity studies using the drift shadow model (Houseworth et al. 2003 [DIRS 164394]). In this model, the flow is significantly perturbed (reduced) beneath the waste emplacement drifts. However, comparisons of transport in this perturbed flow field with transport in an unperturbed flow field show similar results if the transport is initiated in the rock matrix. This has led to a second alternative model, called the fracture-matrix partitioning model, that focuses on the partitioning of radionuclide transport between the fractures and matrix upon exiting the waste emplacement drift. The fracture-matrix partitioning model computes the partitioning, between fractures and matrix, of diffusive radionuclide transport from the invert (for drifts without seepage) into the rock water. The invert is the structure constructed in a drift to provide the floor of the

  13. Self-shielding flex-circuit drift tube, drift tube assembly and method of making

    Science.gov (United States)

    Jones, David Alexander

    2016-04-26

    The present disclosure is directed to an ion mobility drift tube fabricated using flex-circuit technology in which every other drift electrode is on a different layer of the flex-circuit and each drift electrode partially overlaps the adjacent electrodes on the other layer. This results in a self-shielding effect where the drift electrodes themselves shield the interior of the drift tube from unwanted electro-magnetic noise. In addition, this drift tube can be manufactured with an integral flex-heater for temperature control. This design will significantly improve the noise immunity, size, weight, and power requirements of hand-held ion mobility systems such as those used for explosive detection.

  14. Drift chamber detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez Laso, L.

    1989-01-01

    A review of High Energy Physics detectors based on drift chambers is presented. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysied, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author)

  15. Simple chloride sensors for continuous groundwater monitoring

    DEFF Research Database (Denmark)

    Thorn, Paul; Mortensen, John

    2012-01-01

    The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used in continu......The development of chloride sensors which can be used for continuous, on-line monitoring of groundwater could be very valuable in the management of our coastal water resources. However, sensor stability, drift, and durability all need to be addressed in order for the sensors to be used...... in continuous application. This study looks at the development of a simple, inexpensive chloride electrode, and evaluates its performance under continuous use, both in the laboratory and in a field test in a monitoring well. The results from the study showed a consistent response to changing chloride...... concentrations over longer periods. The signal was seen to be stable, with regular drift in both laboratory and field test. In the field application, the sensor signal was corrected for drift, and errors were observed to be under 7% of that of conductivity measurements. The study also found that the chloride...

  16. The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

    Energy Technology Data Exchange (ETDEWEB)

    Nsengiyumva, S. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Department of Physics, Kigali Institute of Education, P.O. Box 5039 Kigali (Rwanda)], E-mail: schadrack.nsengiyumva@uct.ac.za; Ntsoane, T.P. [Nuclear Energy Corporation of South Africa (NECSA), P.O. Box 582 (South Africa); Raji, A.T. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa); Topic, M. [iThemba LABS, Somerset West 7129 (South Africa); Kellermann, G. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas (Brazil); Riviere, J.P. [Laboratoire de Physique des Materiaux UMR6630-CNRS, 86960 (France); Britton, D.T.; Haerting, M. [Department of Physics, University of Cape Town, Rondebosch 7701 (South Africa)

    2009-08-15

    The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

  17. The mutual influence of krypton implantation and pre-existing stress states in polycrystalline alpha titanium

    International Nuclear Information System (INIS)

    Nsengiyumva, S.; Ntsoane, T.P.; Raji, A.T.; Topic, M.; Kellermann, G.; Riviere, J.P.; Britton, D.T.; Haerting, M.

    2009-01-01

    The stress profile in polycrystalline titanium implanted with krypton ions at different fluences has been determined using synchrotron radiation diffraction. For each fluence, the krypton profile has been measured using Rutherford backscattering geometry. The results were compared to model calculations obtained from the SRIM 2008 computer code. A strong stress relaxation was found for high fluence implantation, whereas for low fluence implantation an additional source of tensile stress was introduced in the near surface region. The projected range of the implanted krypton was significantly reduced compared to the expected range. A possible cause of this discrepancy is the drift of implanted ions under the influence of the pre-existing stress gradient.

  18. Construction update and drift velocity calibration for the CLAS drift chamber system

    International Nuclear Information System (INIS)

    Mestayer, M.D.; Barbosa, F.J.; Bonneau, P.; Burtin, E.; Christo, S.; Doolittle, G.; Dytman, S.A.; Gilfoyle, G.P.; Hyde-Wright, C.E.; Klein, A.; Kossov, M.V.; Kuhn, S.E.; Magahiz, R.; Miskimen, R.A.; Murphy, L.Y.; O'Meara, J.E.; Pyron, T.D.; Qin, L.; Raue, B.A.; Schumacher, R.A.; Tuzel, W.; Weinstein, L.B.; Yegneswaran, A.

    1995-01-01

    We briefly describe the drift chamber system for the CLAS detector at CEBAF, concentrating on the method which will be used to calibrate the drift velocity function. We identify key features of the function which should apply to any small-cell drift chamber geometry in which the cathode and anode surfaces are wires. Using these ideas, we describe a simple method to compensate for variations in the drift velocity function due to environmental changes. (orig.)

  19. Construction update and drift velocity calibration for the CLAS drift chamber system

    Energy Technology Data Exchange (ETDEWEB)

    Mestayer, M.D. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Barbosa, F.J. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Bonneau, P. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Burtin, E. [University of South Carolina, Columbia, SC (United States); Christo, S. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Doolittle, G. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Dytman, S.A. [University of Pittsburg, Pittsburg, PA (United States); Gilfoyle, G.P. [University of Richmond, Richmond, VA (United States); Hyde-Wright, C.E. [Old Dominion University, Norfolk, VA (United States); Klein, A. [Old Dominion University, Norfolk, VA (United States); Kossov, M.V. [Christopher Newport University, Newport News, VA (United States); Kuhn, S.E. [Old Dominion University, Norfolk, VA (United States); Magahiz, R. [Carnegie-Mellon Univ., Pittsburgh, PA (United States); Miskimen, R.A. [University of Massachussetts, Amherst, MA (United States); Murphy, L.Y. [CE Saclay, Gif sur Yvette (France); O`Meara, J.E. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Pyron, T.D. [Old Dominion University, Norfolk, VA (United States); Qin, L. [Old Dominion University, Norfolk, VA (United States); Raue, B.A. [Old Dominion University, Norfolk, VA (United States); Schumacher, R.A. [Carnegie-Mellon Univ., Pittsburgh, PA (United States); Tuzel, W. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Weinstein, L.B. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States); Yegneswaran, A. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

    1995-12-11

    We briefly describe the drift chamber system for the CLAS detector at CEBAF, concentrating on the method which will be used to calibrate the drift velocity function. We identify key features of the function which should apply to any small-cell drift chamber geometry in which the cathode and anode surfaces are wires. Using these ideas, we describe a simple method to compensate for variations in the drift velocity function due to environmental changes. (orig.).

  20. Drift Chambers detectors

    International Nuclear Information System (INIS)

    Duran, I.; Martinez laso, L.

    1989-01-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs

  1. Glass Polarization Induced Drift of a Closed-Loop Micro-Accelerometer

    Directory of Open Access Journals (Sweden)

    Wu Zhou

    2018-01-01

    Full Text Available The glass polarization effects were introduced in this paper to study the main cause of turn-on drift phenomenon of closed-loop micro-accelerometers. The glass substrate underneath the sensitive silicon structure underwent a polarizing process when the DC bias voltage was applied. The slow polarizing process induced an additional electrostatic field to continually drag the movable mass block from one position to another so that the sensing capacitance was changed, which led to an output drift of micro-accelerometers. This drift was indirectly tested by experiments and could be sharply reduced by a shielding layer deposited on the glass substrate because the extra electrical filed was prohibited from generating extra electrostatic forces on the movable fingers of the mass block. The experimental results indicate the average magnitude of drift decreased about 73%, from 3.69 to 0.99 mV. The conclusions proposed in this paper showed a meaningful guideline to improve the stability of micro-devices based on silicon-on-glass structures.

  2. Glass Polarization Induced Drift of a Closed-Loop Micro-Accelerometer.

    Science.gov (United States)

    Zhou, Wu; He, Jiangbo; Yu, Huijun; Peng, Bei; He, Xiaoping

    2018-01-20

    The glass polarization effects were introduced in this paper to study the main cause of turn-on drift phenomenon of closed-loop micro-accelerometers. The glass substrate underneath the sensitive silicon structure underwent a polarizing process when the DC bias voltage was applied. The slow polarizing process induced an additional electrostatic field to continually drag the movable mass block from one position to another so that the sensing capacitance was changed, which led to an output drift of micro-accelerometers. This drift was indirectly tested by experiments and could be sharply reduced by a shielding layer deposited on the glass substrate because the extra electrical filed was prohibited from generating extra electrostatic forces on the movable fingers of the mass block. The experimental results indicate the average magnitude of drift decreased about 73%, from 3.69 to 0.99 mV. The conclusions proposed in this paper showed a meaningful guideline to improve the stability of micro-devices based on silicon-on-glass structures.

  3. Abstraction of Drift Seepage

    International Nuclear Information System (INIS)

    J.T. Birkholzer

    2004-01-01

    This model report documents the abstraction of drift seepage, conducted to provide seepage-relevant parameters and their probability distributions for use in Total System Performance Assessment for License Application (TSPA-LA). Drift seepage refers to the flow of liquid water into waste emplacement drifts. Water that seeps into drifts may contact waste packages and potentially mobilize radionuclides, and may result in advective transport of radionuclides through breached waste packages [''Risk Information to Support Prioritization of Performance Assessment Models'' (BSC 2003 [DIRS 168796], Section 3.3.2)]. The unsaturated rock layers overlying and hosting the repository form a natural barrier that reduces the amount of water entering emplacement drifts by natural subsurface processes. For example, drift seepage is limited by the capillary barrier forming at the drift crown, which decreases or even eliminates water flow from the unsaturated fractured rock into the drift. During the first few hundred years after waste emplacement, when above-boiling rock temperatures will develop as a result of heat generated by the decay of the radioactive waste, vaporization of percolation water is an additional factor limiting seepage. Estimating the effectiveness of these natural barrier capabilities and predicting the amount of seepage into drifts is an important aspect of assessing the performance of the repository. The TSPA-LA therefore includes a seepage component that calculates the amount of seepage into drifts [''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504], Section 6.3.3.1)]. The TSPA-LA calculation is performed with a probabilistic approach that accounts for the spatial and temporal variability and inherent uncertainty of seepage-relevant properties and processes. Results are used for subsequent TSPA-LA components that may handle, for example, waste package corrosion or radionuclide transport

  4. Time dependent drift Hamiltonian

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1982-04-01

    The motion of individual charged particles in a given magnetic and an electric fields is discussed. An idea of a guiding center distribution function f is introduced. The guiding center distribution function is connected to the asymptotic Hamiltonian through the drift kinetic equation. The general non-stochastic magnetic field can be written in a contravariant and a covariant forms. The drift Hamiltonian is proposed, and the canonical gyroradius is presented. The proposed drift Hamiltonian agrees with Alfven's drift velocity to lowest non-vanishing order in the gyroradius. The relation between the exact, time dependent equations of motion and the guiding center equation is clarified by a Lagrangian analysis. The deduced Lagrangian represents the drift motion. (Kato, T.)

  5. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    D. Kicker

    2004-01-01

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal stress. (3) The DRKBA

  6. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. Kicker

    2004-09-16

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal

  7. Occlusal considerations for dental implant restorations.

    Science.gov (United States)

    Bergmann, Ranier H

    2014-01-01

    When placed, dental implants are put into an ever-changing oral environment in which teeth can continue to migrate. Yet, the implants themselves are ankylosed. This can lead to occlusal instability. Teeth may continue to erupt, leaving the implants in infraocclusion. Teeth may move mesially away from an implant, requiring modification to close an open contact point. Friction in the connection between teeth and implants can lead to intrusion of teeth and damage to the periodontal attachment apparatus. Implant occlusion with shallow incisal guidance minimizes lateral and tipping forces. Cross-arch stabilization allows the best distribution of occlusal forces. The choice of restorative materials influences long-term occlusal stability.

  8. Construction of a long-distance, sharply curved underground sewerage system by the pit/drift continuous shielding method. Construction of the Arakawa trunk line by the Tokyo Metropolitan Government; Juo renzoku shield koho ni yoru chokyori kyukyokusen seko. Tokyoto gesuidokyoku Arakawa kansen koji

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, Y.; Okai, F.; Akasaka, J.

    1998-06-25

    The problems encountered in construction of sewarage systems in urban areas are reduced pitting sites, and construction of deeper, longer-distance and more sharply curved systems, resulting from overpopulation both on and under the ground. The Arakawa trunk line, constructed by the Tokyo Metropolitan Government, is to connect the existing Mikawashima sewage plant to Higashioku Sewage Purification Center now under construction, 2400m in total length, 40m as pit depth and 15m in the minimum curvature R, and needs shielding works for segment external forms of 4700mm. The construction method employed is the pit/drift continuous shielding method, which allows continuous works from a pit to drift by a single shielding machine. The machine is equipped with a spherical body holding a drift shielding machine built in a pit shielding machine, to excavate a pit to a given depth, and then a drift after turning the spherical body by 90deg. Each pit is equipped with a lift and each drift with an adequate system to move the segments. Bag-equipped segments are used for sharp curves. The pit/drift shielding method has been already applied to 5 cases, including the Arakawa trunk line construction, centered by those for sewarage systems. 1 ref., 6 figs.

  9. Continuous non-invasive blood glucose monitoring by spectral image differencing method

    Science.gov (United States)

    Huang, Hao; Liao, Ningfang; Cheng, Haobo; Liang, Jing

    2018-01-01

    Currently, the use of implantable enzyme electrode sensor is the main method for continuous blood glucose monitoring. But the effect of electrochemical reactions and the significant drift caused by bioelectricity in body will reduce the accuracy of the glucose measurements. So the enzyme-based glucose sensors need to be calibrated several times each day by the finger-prick blood corrections. This increases the patient's pain. In this paper, we proposed a method for continuous Non-invasive blood glucose monitoring by spectral image differencing method in the near infrared band. The method uses a high-precision CCD detector to switch the filter in a very short period of time, obtains the spectral images. And then by using the morphological method to obtain the spectral image differences, the dynamic change of blood sugar is reflected in the image difference data. Through the experiment proved that this method can be used to monitor blood glucose dynamically to a certain extent.

  10. Drift chamber

    International Nuclear Information System (INIS)

    Inagaki, Yosuke

    1977-01-01

    Drift chamber is becoming an important detector in high energy physics as a precision and fast position detector because of its high spatial resolution and count-rate. The basic principle is that it utilizes the drift at constant speed of electrons ionized along the tracks of charged particles towards the anode wire in the nearly uniform electric field. The method of measuring drift time includes the analog and digital ones. This report describes about the construction of and the application of electric field to the drift chamber, mathematical analysis on the electric field and equipotential curve, derivation of spatial resolution and the factor for its determination, and selection of gas to be used. The performance test of the chamber was carried out using a small test chamber, the collimated β source of Sr-90, and 500 MeV/C electron beam from the 1.3 GeV electron synchrotron in the Institute of Nuclear Study, University of Tokyo. Most chambers to date adopted one dimensional read-out, but it is very advantageous if the two dimensional read-out is feasible with one chamber when the resolution in that direction is low. The typical methods of delay line and charge division for two dimensional read-out are described. The development of digital read-out system is underway, which can process the signal of a large scale drift chamber at high speed. (Wakatsuki, Y.)

  11. Consistent guiding center drift theories

    International Nuclear Information System (INIS)

    Wimmel, H.K.

    1982-04-01

    Various guiding-center drift theories are presented that are optimized in respect of consistency. They satisfy exact energy conservation theorems (in time-independent fields), Liouville's theorems, and appropriate power balance equations. A theoretical framework is given that allows direct and exact derivation of associated drift-kinetic equations from the respective guiding-center drift-orbit theories. These drift-kinetic equations are listed. Northrop's non-optimized theory is discussed for reference, and internal consistency relations of G.C. drift theories are presented. (orig.)

  12. Spray particle drift mitigation using field corn (Zea mays L.) as a drift barrier.

    Science.gov (United States)

    Vieira, Bruno C; Butts, Thomas R; Rodrigues, Andre O; Golus, Jeffrey A; Schroeder, Kasey; Kruger, Greg R

    2018-04-24

    Herbicide particle drift reduces application efficacy and can cause severe impacts on nearby vegetation depending on the herbicide mode-of-action, exposure level, and tolerance to the herbicide. A particle drift mitigation effort placing windbreaks or barriers on the field boundaries to reduce off-target movement of spray particles has been utilized in the past. The objective of this research was to evaluate the effectiveness of field corn (Zea mays L.) at different heights as a particle drift barrier. Applications with a non-air inclusion flat fan nozzle (ER11004) resulted in greater particle drift when compared to an air inclusion nozzle (TTI11004). Eight rows of corn were used as barriers (0.91, 1.22, and 1.98 m height) which reduced the particle drift for both nozzles, especially at shorter downwind distances. Applications with the ER11004 nozzle without corn barriers had 1% of the applied rate (D 99 ) predicted to deposit at 14.8 m downwind, whereas this distance was reduced (up to 7-fold) when applications were performed with corn barriers. The combination of corn drift barriers and nozzle selection (TTI11004) provided satisfactory particle drift reduction when the D 99 estimates were compared to applications with the ER11004 nozzle without corn barriers (up to 10-fold difference). The corn drift barriers were effective in reducing particle drift from applications with the ER11004 and the TTI11004 nozzles (Fine and Ultra Coarse spray classifications, respectively). The corn drift barrier had appropriate porosity and width as the airborne spray was captured within its canopy instead of deflecting up and over it. This article is protected by copyright. All rights reserved.

  13. Collisional drift fluids and drift waves

    International Nuclear Information System (INIS)

    Pfirsch, D.; Correa-Restrepo, D.

    1995-05-01

    The usual theoretical description of drift-wave turbulence (considered to be one possible cause of anomalous transport in a plasma), e.g. the Hasegawa-Wakatani theory, makes use of various approximations, the effect of which is extremely difficult to assess. This concerns in particular the conservation laws for energy and momentum. The latter is important as concerns charge separation and resulting electric fields which are possibly related to the L-H transition. Energy conservation is crucial for the stability behaviour; it will be discussed via an example. New collisional multispecies drift-fluid equations were derived by a new method which yields in a transparent way conservation of energy and total angular momentum, and the law for energy dissipation. Both electrostatic and electromagnetic field variations are considered. The method is based primarily on a Lagrangian for dissipationless fluids in drift approximation with isotropic pressures. The dissipative terms are introduced by adding corresponding terms to the ideal equations of motion and of the pressures. The equations of motion, of course, no longer result from a Lagrangian via Hamilton's principle. Their relation to the ideal equations imply, however, also a relation to the ideal Lagrangian of which one can take advantage. Instead of introducing heat conduction one can also assume isothermal behaviour, e.g. T ν (x)=const. Assumptions of this kind are often made in the literature. The new method of introducing dissipation is not restricted to the present kind of theories; it can equally well be applied to theories such as multi-fluid theories without using the drift approximation of the present paper. Linear instability is investigated via energy considerations and the implications of taking ohmic resistivity into account are discussed. (orig./WL)

  14. A novel silicon drift detector with two dimensional drift time measurement

    International Nuclear Information System (INIS)

    Hijzen, E.A.; Schooneveld, E.M.; Van Eijk, C.W.E.; Hollander, R.W.; Sarro, P.M.; Van den Bogaard, A.

    1994-01-01

    Until now silicon drift detectors with two dimensional position resolution made use of drift time measurement in one dimension only. The resolution in the other dimension was obtained by dividing the collecting anode into small pixels. In this paper we present a new type of drift detector that uses drift time measurements for both dimensions. The design consists of concentric quadrilateral closed strips with a small collecting anode in the centre. At first electrons will travel perpendicular to the strips until they reach a diagonal. Then they will proceed along this diagonal until they are collected at the centre. Position resolution in two dimensions can be obtained when both the time the electrons need to reach the diagonal and the time they need to reach the centre are measured. The latter is obtained from the collecting anode, the former from a diagonal strip present at the back side of the detector. Compared to common 2D drift detectors this detector offers the advantage of a small amount of readout electronics. It also has the advantage of having just one small collecting anode with a very low capacitance, resulting in low noise and therefore in a good energy resolution. ((orig.))

  15. Drift Scale THM Model

    International Nuclear Information System (INIS)

    Rutqvist, J.

    2004-01-01

    This model report documents the drift scale coupled thermal-hydrological-mechanical (THM) processes model development and presents simulations of the THM behavior in fractured rock close to emplacement drifts. The modeling and analyses are used to evaluate the impact of THM processes on permeability and flow in the near-field of the emplacement drifts. The results from this report are used to assess the importance of THM processes on seepage and support in the model reports ''Seepage Model for PA Including Drift Collapse'' and ''Abstraction of Drift Seepage'', and to support arguments for exclusion of features, events, and processes (FEPs) in the analysis reports ''Features, Events, and Processes in Unsaturated Zone Flow and Transport and Features, Events, and Processes: Disruptive Events''. The total system performance assessment (TSPA) calculations do not use any output from this report. Specifically, the coupled THM process model is applied to simulate the impact of THM processes on hydrologic properties (permeability and capillary strength) and flow in the near-field rock around a heat-releasing emplacement drift. The heat generated by the decay of radioactive waste results in elevated rock temperatures for thousands of years after waste emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, resulting in water redistribution and altered flow paths. These temperatures will also cause thermal expansion of the rock, with the potential of opening or closing fractures and thus changing fracture permeability in the near-field. Understanding the THM coupled processes is important for the performance of the repository because the thermally induced permeability changes potentially effect the magnitude and spatial distribution of percolation flux in the vicinity of the drift, and hence the seepage of water into the drift. This is important because a sufficient amount of water must be available within a

  16. The modulation of galactic cosmic rays as described by a three-dimensional drift model

    International Nuclear Information System (INIS)

    Potgieter, M.S.

    1984-01-01

    An outline of the present state of knowledge about the effect of drift on the modulation of galactic cosmic rays is given. Various observations related to the reversal of the solar magnetic field polarity are discussed. Comprehensive numerical solutions of the steady-state cosmic-ray transport equation in an axially-symmetric three-dimensional heliosphere, including drift are presented. This is an extention of the continuing effort of the past six years to understand the effect and importance of drift on the transport of galactic cosmic rays in the heliosphere. A flat neutral sheet which coincides with the equatorial plane is assumed. A general method of calculating the drift velocity in the neutral sheet including that used previously by other authors is presented. The effect of changing various modulation parameters on the drift solutions are illustrated in detail. The real significance of drift is illustrated by using Gaussian input spectra on the modulation boundary. A carefully selected set of modulation parameters is used to illustrate to what extent a drift model can explain prominent observational features. It is concluded that drift is important in in the process of cosmic-ray transport and must as such be considered in all modulation studies, but that it is not overwhelmingly dominant as previously anticipated

  17. Developing implant dentistry education in Europe: the continuum from undergraduate to postgraduate education and continuing professional development.

    Science.gov (United States)

    Mattheos, N; de Bruyn, H; Hultin, M; Jepsen, S; Klinge, B; Koole, S; Sanz, M; Ucer, C; Lang, N P

    2014-03-01

    Implant dentistry is a treatment modality which has mainstream clinical practice of comprehensive care, which however is not adequately represented in the undergraduate dental curricula. A consensus workshop organised by ADEE in 2008, set the benchmarks for the knowledge and competences a modern dental practitioner must possess with regard to implant dentistry, as well as defined undergraduate and postgraduate pathways for the acquisition of these competences. Today, 5 years later, there exist several challenges for the implementation of these benchmarks in both undergraduate curricula but also post-graduation educational pathways. A consensus workshop was organised by ADEE, bringing together 48 opinion leaders, including academic teachers of all disciplines related to implant dentistry, specialists, representatives of relevant scientific and professional associations, as well as industry delegates. The objectives of the workshop were to evaluate the existing scientific literature, reported experience and best practices in order to identify potential and limitations for the implementation of implant dentistry in the undergraduate curriculum, as well produce recommendations for the optimal educational structures for postgraduate programmes and continuing professional development. The scientific committee conducted two European-wide questionnaire surveys to better document the current state of education in implant dentistry. Upon completion of the surveys, reviewers were appointed to produce three scientific review papers, identifying current achievements and future challenges. Finally, during the 3 days of the workshop, all the evidence was reviewed and the main conclusions and recommendations that were adopted by all participants are reported in the present Consensus Paper. Implementation of implant dentistry in the undergraduate curriculum has improved significantly, but still lags behind the benchmarks set in 2008 and the diversity between institutions remains

  18. Laboratory Course on Drift Chambers

    International Nuclear Information System (INIS)

    Garcia-Ferreira, Ix-B.; Garcia-Herrera, J.; Villasenor, L.

    2006-01-01

    Drift chambers play an important role in particle physics experiments as tracking detectors. We started this laboratory course with a brief review of the theoretical background and then moved on to the the experimental setup which consisted of a single-sided, single-cell drift chamber. We also used a plastic scintillator paddle, standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. During the laboratory session the students performend measurements of the following quantities: a) drift velocities and their variations as function of the drift field; b) gas gains and c) diffusion of electrons as they drifted in the gas

  19. Characteristic parameters of drift chambers calculation

    International Nuclear Information System (INIS)

    Duran, I.; Martinez-Laso, L.

    1989-01-01

    We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs

  20. Treatment of PPROM with anhydramnion in humans: first experience with different amniotic fluid substitutes for continuous amnioinfusion through a subcutaneously implanted port system.

    Science.gov (United States)

    Tchirikov, Michael; Bapayeva, Gauri; Zhumadilov, Zhaxybay Sh; Dridi, Yasmina; Harnisch, Ralf; Herrmann, Angelika

    2013-11-01

    This study aims to treat patients with preterm premature rupture of the membranes (PPROM) and anhydramnion using continuous amnioinfusion through a subcutaneously implanted port system. An amniotic fluid replacement port system was implanted in seven patients with PPROM and anhydramnion starting at the 20th week of gestation (range, 14-26 weeks) for long-term amnioinfusion. Saline solutions (2 L/day; Jonosteril(®), Sterofundin(®), isotonic NaCl 0.9% solution, lactated Ringer's solution) and a hypotonic aqueous composition with reduced chloride content similar to the electrolyte concentration of human amniotic fluid were used for the continuous amnioinfusion. The mean duration of the PPROM delivery interval continued for 49 days (range, 9-69 days), with 3 weeks of amnioinfusion via the port system (range, 4-49). The newborns showed no signs of lung hypoplasia. Long-term lavage of the amniotic cavity via a subcutaneously implanted port system in patients with PPROM and anhydramnion may help prolong the pregnancy and avoid fetal lung hypoplasia. A hypotonic aqueous composition with reduced chloride content similar to human amniotic fluid can be safely used for amnioinfusion. Prospective randomized studies are ongoing.

  1. Limits of neutral drift: lessons from the in vitro evolution of two ribozymes.

    Science.gov (United States)

    Petrie, Katherine L; Joyce, Gerald F

    2014-10-01

    The relative contributions of adaptive selection and neutral drift to genetic change are unknown but likely depend on the inherent abundance of functional genotypes in sequence space and how accessible those genotypes are to one another. To better understand the relative roles of selection and drift in evolution, local fitness landscapes for two different RNA ligase ribozymes were examined using a continuous in vitro evolution system under conditions that foster the capacity for neutral drift to mediate genetic change. The exploration of sequence space was accelerated by increasing the mutation rate using mutagenic nucleotide analogs. Drift was encouraged by carrying out evolution within millions of separate compartments to exploit the founder effect. Deep sequencing of individuals from the evolved populations revealed that the distribution of genotypes did not escape the starting local fitness peak, remaining clustered around the sequence used to initiate evolution. This is consistent with a fitness landscape where high-fitness genotypes are sparse and well isolated, and suggests, at least in this context, that neutral drift alone is not a primary driver of genetic change. Neutral drift does, however, provide a repository of genetic variation upon which adaptive selection can act.

  2. The successful implantation of continuous-flow left ventricular assist device as a destination therapy in Korea: echocardiographic assessment.

    Science.gov (United States)

    Lee, Ga Yeon; Park, Sung-Ji; Kim, Sujin; Choi, Namgyung; Jeong, Dong Seop; Jeon, Eun-Seok; Lee, Young Tak

    2014-01-01

    Left ventricular assist device (LVAD) is a good treatment option for the patients ineligible for cardiac transplantation. Several studies have demonstrated that a ventricular assist device improves the quality of life and prognosis of the patients with end-stage heart failure. A 75-yr-old man debilitated with New York Heart Association (NYHA) functional class III-IV due to severe left ventricular systolic dysfunction received LVAD implantation as a destination therapy. The patient was discharged with improved functional status (NYHA functional class II) after appropriate cardiac rehabilitation and education about how to manage the device and potential emergency situations. This is the first case of successful continuous-flow LVAD implantation as a destination therapy in Korea.

  3. Generalized drift-flux correlation

    International Nuclear Information System (INIS)

    Takeuchi, K.; Young, M.Y.; Hochreiter, L.E.

    1991-01-01

    A one-dimensional drift-flux model with five conservation equations is frequently employed in major computer codes, such as TRAC-PD2, and in simulator codes. In this method, the relative velocity between liquid and vapor phases, or slip ratio, is given by correlations, rather than by direct solution of the phasic momentum equations, as in the case of the two-fluid model used in TRAC-PF1. The correlations for churn-turbulent bubbly flow and slug flow regimes were given in terms of drift velocities by Zuber and Findlay. For the annular flow regime, the drift velocity correlations were developed by Ishii et al., using interphasic force balances. Another approach is to define the drift velocity so that flooding and liquid hold-up conditions are properly simulated, as reported here. The generalized correlation is used to reanalyze the MB-2 test data for two-phase flow in a large-diameter pipe. The results are applied to the generalized drift flux velocity, whose relationship to the other correlations is discussed. Finally, the generalized drift flux correlation is implemented in TRAC-PD2. Flow reversal from countercurrent to cocurrent flow is computed in small-diameter U-shaped tubes and is compared with the flooding curve

  4. The CLEO III drift chamber

    CERN Document Server

    Peterson, D; Briere, R A; Chen, G; Cronin-Hennessy, D; Csorna, S; Dickson, M; Dombrowski, S V; Ecklund, K M; Lyon, A; Marka, S; Meyer, T O; Patterson, J R; Sadoff, A; Thies, P; Thorndike, E H; Urner, D

    2002-01-01

    The CLEO group at the Cornell Electron Storage Ring has constructed and commissioned a new central drift chamber. With 9796 cells arranged in 47 layers ranging in radius from 13.2 to 79 cm, the new drift chamber has a smaller outer radius and fewer wires than the drift chamber it replaces, but allows the CLEO tracking system to have improved momentum resolution. Reduced scattering material in the chamber gas and in the inner skin separating the drift chamber from the silicon vertex detector provides a reduction of the multiple scattering component of the momentum resolution and an extension of the usable measurement length into the silicon. Momentum resolution is further improved through quality control in wire positioning and symmetry of the electric fields in the drift cells which have provided a reduction in the spatial resolution to 88 mu m (averaged over the full drift range).

  5. Rectangular drift tube characteristics

    International Nuclear Information System (INIS)

    Denisov, D.S.; Musienko, Yu.V.

    1985-01-01

    Results on the study of the characteristics of a 50 x 100 mm aluminium drift tube are presented. The tube was filled with argon-methane and argon-isobutane mixtures. With 16 per cent methane concentration the largest deviation from a linear relation between the drift time and the drift path over 50 mm is less than 2 mm. The tube filled with argon-isobutane mixture is capable of operating in a limited streamer mode

  6. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    Energy Technology Data Exchange (ETDEWEB)

    E. Gonnenthal; N. Spyoher

    2001-02-05

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) 2000 [153447]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M and O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: (1) Performance Assessment (PA); (2) Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); (3) UZ Flow and Transport Process Model Report (PMR); and (4) Near-Field Environment (NFE) PMR. The work scope for this activity is presented in the TWPs cited above, and summarized as follows: continue development of the repository drift-scale THC seepage model used in support of the TSPA in-drift geochemical model; incorporate heterogeneous fracture property realizations; study sensitivity of results to changes in input data and mineral assemblage; validate the DST model by comparison with field data; perform simulations to predict mineral dissolution and precipitation and their effects on fracture properties and chemistry of water (but not flow rates) that may seep into drifts; submit modeling results to the TDMS and document the models. The model development, input data

  7. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    International Nuclear Information System (INIS)

    Sonnenthale, E.

    2001-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) 2000 [1534471]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M and O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: Performance Assessment (PA); Near-Field Environment (NFE) PMR; Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); and UZ Flow and Transport Process Model Report (PMR). The work scope for this activity is presented in the TWPs cited above, and summarized as follows: Continue development of the repository drift-scale THC seepage model used in support of the TSPA in-drift geochemical model; incorporate heterogeneous fracture property realizations; study sensitivity of results to changes in input data and mineral assemblage; validate the DST model by comparison with field data; perform simulations to predict mineral dissolution and precipitation and their effects on fracture properties and chemistry of water (but not flow rates) that may seep into drifts; submit modeling results to the TDMS and document the models. The model development, input data, sensitivity and validation studies described in this AMR are

  8. Drift-modeling and monitoring comparisons

    International Nuclear Information System (INIS)

    Chen, N.C.J.; Hanna, S.R.

    1977-01-01

    Congress is looking into the conglomeration of nuclear reactors into energy centers of limited area. Drift from cooling towers can corrode and damage structures in the immediate vicinity of the towers, cause a public nuisance if located near parking lots or high-density traffic areas, and endanger local vegetation. The estimation of salt deposition has relied primarily on predictions from a variety of models, with very few direct measurements. One of the major efforts in our program is to evaluate the assumptions, limitations, and applicabilities of various analytical models for drift deposition prediction. Several drift deposition models are compared using a set of standard input conditions. The predicted maximum drift deposition differs by two orders of magnitude, and the downwind locations of the maximum differ by one order of magnitude. The discrepancies are attributed mainly to different assumptions in the models regarding the initial effective height of the droplets. Current programs in which drift characteristics at the tower mouth and drift deposition downwind of the tower are being measured are summarized. At the present time, drift deposition measurements, sufficiently comprehensive for model verifications, are unavailable. Hopefully, the Chalk Point Program will satisfy this need

  9. Drifting oscillations in axion monodromy

    Energy Technology Data Exchange (ETDEWEB)

    Flauger, Raphael [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); McAllister, Liam [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Silverstein, Eva [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States); Westphal, Alexander, E-mail: flauger@physics.ucsd.edu, E-mail: mcallister@cornell.edu, E-mail: evas@stanford.edu, E-mail: alexander.westphal@desy.de [Theory Group, Deutsches Elektronen-Synchrotron DESY, D-22603 Hamburg (Germany)

    2017-10-01

    We study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. We use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.

  10. Drifting oscillations in axion monodromy

    International Nuclear Information System (INIS)

    Flauger, Raphael; Westphal, Alexander

    2014-12-01

    We study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. We use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.

  11. Style drift in private equity

    NARCIS (Netherlands)

    Cumming, D.; Fleming, G.; Schwienbacher, A.

    2009-01-01

    We introduce the concept of style drift to private equity investment. We present theory and evidence pertaining to style drifts in terms of a fund manager's stated focus on particular stages of entrepreneurial development. We develop a model that derives conditions under which style drifts are less

  12. Implant experience with an implantable hemodynamic monitor for the management of symptomatic heart failure.

    Science.gov (United States)

    Steinhaus, David; Reynolds, Dwight W; Gadler, Fredrik; Kay, G Neal; Hess, Mike F; Bennett, Tom

    2005-08-01

    Management of congestive heart failure is a serious public health problem. The use of implantable hemodynamic monitors (IHMs) may assist in this management by providing continuous ambulatory filling pressure status for optimal volume management. The Chronicle system includes an implanted monitor, a pressure sensor lead with passive fixation, an external pressure reference (EPR), and data retrieval and viewing components. The tip of the lead is placed near the right ventricular outflow tract to minimize risk of sensor tissue encapsulation. Implant technique and lead placement is similar to that of a permanent pacemaker. After the system had been successfully implanted in 148 patients, the type and frequency of implant-related adverse events were similar to a single-chamber pacemaker implant. R-wave amplitude was 15.2 +/- 6.7 mV and the pressure waveform signal was acceptable in all but two patients in whom presence of artifacts required lead repositioning. Implant procedure time was not influenced by experience, remaining constant throughout the study. Based on this evaluation, permanent placement of an IHM in symptomatic heart failure patients is technically feasible. Further investigation is warranted to evaluate the use of the continuous hemodynamic data in management of heart failure patients.

  13. Collisional drift fluid equations and implications for drift waves

    International Nuclear Information System (INIS)

    Pfirsch, Dieter; Correa-Restrepo, Dario

    1996-01-01

    The usual theoretical description of drift-wave turbulence (considered to be one possible cause of anomalous transport in a plasma), e.g. the Hasegawa-Wakatani theory, makes use of various approximations, the effects of which are extremely difficult to assess. This concerns in particular the conservation laws for energy and momentum. The latter law is important in relation to charge separation and the resulting electric fields, which are possibly related to the L-H transition. Energy conservation is crucial to the stability behaviour, it will be discussed by means of an example. New collisional multi-species drift-fluid equations were derived by a new method which yields, in a transparent way, conservation of energy and total angular momentum and the law for energy dissipation. Both electrostatic and electromagnetic field variations are considered. The only restriction involved is the validity of the drift approximation; in particular, there are no assumptions restricting the geometry of the system. The method is based primarily on a Lagrangian for dissipationless fluids in the drift approximation with isotropic pressures. The dissipative terms are introduced by adding corresponding terms to the ideal equations of motion and of the pressures. The equations of motion, of course, no longer result from a Lagrangian via Hamilton's principle. However, their relation to the ideal equations also implies a relation to the ideal Lagrangian, which can be used to advantage. Instead of introducing heat conduction one can also assume isothermal behaviour, e.g. T v (x) = constant. Assumptions of this kind are often made in the literature. The new method of introducing dissipation is not restricted to the present kind of theory; it can equally well be applied to theories such as multi-fluid theories without using the drift approximation of the present paper. (author)

  14. Drift chamber performance in the field of a superconducting magnet: measurement of the drift angle

    International Nuclear Information System (INIS)

    Sanders, G.H.; Sherman, S.; McDonald, K.T.; Smith, A.J.S.; Thaler, J.J.

    1977-01-01

    Results are presented of the first measurements in a study of drift chamber performance in magnetic fields up to 6 tesla. The angle of the electron drift was measured as a function of electric and magnetic field intensity. It appears that even at the high fields of superconducting magnets (3 to 6 tesla) the drift angle induced by the Lorentz force can be corrected for with tilted electric drift fields and/or the use of Xenon gas. At 3 tesla a drift field tilted at 45 0 with a magnitude of 3.5 kV/cm should restore normal operating conditions. At 4 tesla, a 45 0 tilt field would have a magnitude 5 kV/cm

  15. Clean industrial room for drift tube assembling

    International Nuclear Information System (INIS)

    Glonti, G.L.; Gongadze, A.L.; Evtukhovich, P.G.

    2001-01-01

    Description of a clean industrial room for assembly of drift tubes for the muon spectrometer of the ATLAS experiment is presented. High quality specifications on the detectors to be produced demanded creation of a workplace with stable temperature and humidity, as well as minimum quantity of dust in the room. Checking of parameters of intra-room air during long period of continuous work has confirmed correctness of the designed characteristics of the climatic system installed in the clean room. The room large volume (∼ 190 m 3 ), the powerful and flexible climatic system, and simplicity of service allow assembling of detectors with length up to 5 m. Subsequent checking of functionality of the assembled detectors has shown high quality of assembling (the amount of rejected tubes does not exceed 2%). It demonstrates conformity to the assembling quality requirements for mass production of drift chambers for the muon spectrometer. (author)

  16. Clean Industrial Room for Drift Tube Assembling

    CERN Document Server

    Glonti, GL; Evtoukhovitch, P G; Kroa, G; Manz, A; Potrap, I N; Rihter, P; Stoletov, G D; Tskhadadze, E G; Chepurnov, V F; Chirkov, A V; Shelkov, G A

    2001-01-01

    Description of a clean industrial room for assembly of drift tubes for the muon spectrometer of the ATLAS experiment is presented. High quality specifications on the detectors to be produced demanded creation of a workplace with stable temperature and humidity, as well as minimum quantity of dust in the room. Checking of parameters of intra-room air during long period of continuous work has been confirmed correctness of the designed characteristics of the climatic system installed in the clean room. The room large volum (\\sim 190 m^3), the powerful and flexible climatic system, and simplicity of service allow assembling of detectors with length up to 5 m. Subsequent checking of functionality of the assembled detectors has shown high quality of assembling (the amount of rejected tubes does not exceed 2 %). It demonstrates conformity to the assembling quality requirements for mass production of drift chambers for the muon spectrometer.

  17. Dynamic Portfolio Optimization with Transaction Costs and State-Dependent Drift

    DEFF Research Database (Denmark)

    Palczewski, Jan; Poulsen, Rolf; Schenk-Hoppe, Klaus Reiner

    2015-01-01

    The problem of dynamic portfolio choice with transaction costs is often addressed by constructing a Markov Chain approximation of the continuous time price processes. Using this approximation, we present an efficient numerical method to determine optimal portfolio strategies under time- and state......-dependent drift and proportional transaction costs. This scenario arises when investors have behavioral biases or the actual drift is unknown and needs to be estimated. Our numerical method solves dynamic optimal portfolio problems with an exponential utility function for time-horizons of up to 40 years....... It is applied to measure the value of information and the loss from transaction costs using the indifference principle....

  18. Computer controlled drifting of Si(Li) detectors

    International Nuclear Information System (INIS)

    Landis, D.A.; Wong, Y.K.; Walton, J.T.; Goulding, F.S.

    1989-01-01

    A relatively inexpensive computer-controlled system for performing the drift process used in fabricating Si(Li) detectors is described. The system employs a small computer to monitor the leakage current, applied voltage and temperature on eight individual drift stations. The associated computer program initializes the drift process, monitors the drift progress and then terminates the drift when an operator set drift time has elapsed. The improved control of the drift with this system has been well demonstrated over the past three years in the fabrication of a variety of Si(Li) detectors. A few representative system responses to detector behavior during the drift process are described

  19. Modeling concept drift

    DEFF Research Database (Denmark)

    Borchani, Hanen; Martinez, Ana Maria; Masegosa, Andrés R.

    2015-01-01

    An often used approach for detecting and adapting to concept drift when doing classification is to treat the data as i.i.d. and use changes in classification accuracy as an indication of concept drift. In this paper, we take a different perspective and propose a framework, based on probabilistic ...... data set from a Spanish bank....

  20. The Drift Burst Hypothesis

    OpenAIRE

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    2016-01-01

    The Drift Burst Hypothesis postulates the existence of short-lived locally explosive trends in the price paths of financial assets. The recent US equity and Treasury flash crashes can be viewed as two high profile manifestations of such dynamics, but we argue that drift bursts of varying magnitude are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the...

  1. Field investigation of the drift shadow

    International Nuclear Information System (INIS)

    Su, Grace W.; Kneafsey, Timothy J.; Ghezzehei, Teamrat A.; Marshall, Brian D.; Cook, Paul J.

    2005-01-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rockmass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming its existence have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow and the corresponding hydrological process at the Hazel-Atlas silica-sandmine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine Formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rockmass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content and chemical constituents. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift. Tensiometers, electrical resistance probes, neutron probes, and ground

  2. FIELD INVESTIGATION OF THE DRIFT SHADOW

    International Nuclear Information System (INIS)

    G.W. Su; T.J. Kneafsey

    2006-01-01

    A drift shadow is an area immediately beneath an underground void that, in theory, will be relatively drier than the surrounding rock mass. Numerical and analytical models of water flow through unsaturated rock predict the existence of a drift shadow, but field tests confirming the existence of the drift shadow have yet to be performed. Proving the existence of drift shadows and understanding their hydrologic and transport characteristics could provide a better understanding of how contaminants move in the subsurface if released from waste emplacement drifts such as the proposed nuclear waste repository at Yucca Mountain, Nevada. We describe the field program that will be used to investigate the existence of a drift shadow--and the corresponding hydrological process at the Hazel-Atlas silica-sand mine located at the Black Diamond Mines Regional Preserve in Antioch, California. The location and configuration of this mine makes it an excellent site to observe and measure drift shadow characteristics. The mine is located in a porous sandstone unit of the Domengine formation, an approximately 230 meter thick series of interbedded Eocene-age shales, coals, and massive-bedded sandstones. The mining method used at the mine required the development of two parallel drifts, one above the other, driven along the strike of the mined sandstone stratum. This configuration provides the opportunity to introduce water into the rock mass in the upper drift and to observe and measure its flow around the underlying drift. The passive and active hydrologic tests to be performed are described. In the passive method, cores will be obtained in a radial pattern around a drift and will be sectioned and analyzed for in-situ water content using a gravimetric technique, as well as analyzed for chemistry. With the active hydrologic test, water will be introduced into the upper drift of the two parallel drifts and the flow of the water will be tracked as it passes near the bottom drift

  3. CTF Void Drift Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Salko, Robert K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gosdin, Chris [Pennsylvania State Univ., University Park, PA (United States); Avramova, Maria N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gergar, Marcus [Pennsylvania State Univ., University Park, PA (United States)

    2015-10-26

    This milestone report is a summary of work performed in support of expansion of the validation and verification (V&V) matrix for the thermal-hydraulic subchannel code, CTF. The focus of this study is on validating the void drift modeling capabilities of CTF and verifying the supporting models that impact the void drift phenomenon. CTF uses a simple turbulent-diffusion approximation to model lateral cross-flow due to turbulent mixing and void drift. The void drift component of the model is based on the Lahey and Moody model. The models are a function of two-phase mass, momentum, and energy distribution in the system; therefore, it is necessary to correctly model the ow distribution in rod bundle geometry as a first step to correctly calculating the void distribution due to void drift.

  4. Ion acceleration in non-equilibrium plasmas driven by fast drifting electron

    Energy Technology Data Exchange (ETDEWEB)

    Castro, G. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Di Bartolo, F., E-mail: fdibartolo@unime.it [Università di Messina, V.le F. Stagno D’Alcontres 31, 98166, Messina (Italy); Gambino, N. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Metodologie Fisiche e Chimiche per L’ingegneria, Viale A.Doria 6, 95125 Catania (Italy); Mascali, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Romano, F.P. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CNR-IBAM Via Biblioteca 4, 95124 Catania (Italy); Anzalone, A.; Celona, L.; Gammino, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Di Giugno, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Lanaia, D. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Miracoli, R. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Università degli Studi di Catania, Dipartimento di Fisica e Astronomia, V. S.Sofia 64, 95123 Catania (Italy); Serafino, T. [CSFNSM, Viale A. Doria 6, 95125 Catania (Italy); Tudisco, S. [INFN- Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); CSFNSM, Viale A. Doria 6, 95125 Catania (Italy)

    2013-05-01

    We hereby present results on ion acceleration mechanisms in non equilibrium plasmas generated by microwaves or high intensity laser pulses. Experiments point out that in magnetized plasmas X–B conversion takes place for under resonance values of the magnetic field, i.e. an electromagnetic mode is converted into an electrostatic wave. The strong self-generated electric field, of the order of 10{sup 7} V/m, causes a E × B drift which accelerates both ions and electrons, as it is evident by localized sputtering in the plasma chamber. These fields are similar (in magnitude) to the ones obtainable in laser generated plasmas at intensity of 10{sup 12} W/cm{sup 2}. In this latter case, we observe that the acceleration mechanism is driven by electrons drifting much faster than plasma bulk, thus generating an extremely strong electric field ∼10{sup 7} V/m. The two experiments confirm that ions acceleration at low energy is possible with table-top devices and following complementary techniques: i.e. by using microwave-driven (producing CW beams) plasmas, or non-equilibrium laser-driven plasmas (producing pulsed beams). Possible applications involve ion implantation, materials surface modifications, ion beam assisted lithography, etc.

  5. Implants for orthodontic anchorage

    Science.gov (United States)

    Zheng, Xiaowen; Sun, Yannan; Zhang, Yimei; Cai, Ting; Sun, Feng; Lin, Jiuxiang

    2018-01-01

    Abstract Implantanchorage continues to receive much attention as an important orthodontic anchorage. Since the development of orthodontic implants, the scope of applications has continued to increase. Although multiple reviews detailing implants have been published, no comprehensive evaluations have been performed. Thus, the purpose of this study was to comprehensively evaluate the effects of implants based on data published in review articles. An electronic search of the Cochrane Library, Medline, Embase, Ebsco and Sicencedirect for reviews with “orthodontic” and “systematic review or meta analysis” in the title, abstract, keywords, or full text was performed. A subsequent manual search was then performed to identify reviews concerning orthodontic implants. A manual search of the orthodontic journals American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), European Journal of Orthodontics (EJO), and Angle Othodontist was also performed. Such systematic reviews that evaluated the efficacy and safety of orthodontic implants were used to indicate success rates and molar movements. A total of 23 reviews were included in the analysis. The quality of each review was assessed using a measurement tool for Assessment of Multiple Systematic Reviews (AMSTAR), and the review chosen to summarize outcomes had a quality score of >6. Most reviews were less than moderate quality. Success rates of implants ranged in a broad scope, and movement of the maxillary first molar was superior with implants compared with traditional anchorage. PMID:29595673

  6. Continuous ambulatory right heart pressure measurements with an implantable hemodynamic monitor: a multicenter, 12-month follow-up study of patients with chronic heart failure.

    Science.gov (United States)

    Magalski, Anthony; Adamson, Philip; Gadler, Frederick; Böehm, Michael; Steinhaus, David; Reynolds, Dwight; Vlach, Kathryn; Linde, Cecilia; Cremers, Bodo; Sparks, Brandon; Bennett, Tom

    2002-04-01

    We describe the performance of an implantable hemodynamic monitor (IHM) that allows continuous recording of heart rate, patient activity levels, and right ventricular systolic, right ventricular diastolic, and estimated pulmonary artery diastolic pressures. Pressure parameters derived from the implantable monitor were correlated to measurements made with a balloon-tipped catheter to establish accuracy and reproducibility over time in patients with chronic heart failure (CHF). IHM devices were implanted in 32 patients with CHF (left ventricular ejection fraction, 29% +/- 11%; range, 14%-62%) and were tested with right heart catheterization at implantation and 3, 6, and 12 months later. Hemodynamic variables were digitally recorded simultaneously from the IHM and catheter. Values were recorded during supine rest, peak response of Valsalva maneuver, sitting, peak of a 2-stage (25-50 W) bicycle exercise test, and final rest period. The median of 21 paired beat-to-beat cardiac cycles was analyzed for each intervention. A total of 217 paired data values from all maneuvers were analyzed for 32 patients at implantation and 129 paired data values for 20 patients at 1 year. The IHM and catheter values were not different at baseline or at 1 year (P >.05). Combining all interventions, correlation coefficients were 0.96 and 0.94 for right ventricular systolic pressure, 0.96 and 0.83 for right ventricular diastolic pressure, and 0.87 and 0.87 for estimated pulmonary artery diastolic pressure at implantation and 1 year, respectively. The IHM and a standard reference pressure system recorded comparable right heart pressure values in patients with CHF. This implantable pressure transducer is accurate over time and provides a means to precisely monitor the hemodynamic condition of patients with CHF in a continuous fashion.

  7. Evaluation of intensity drift correction strategies using MetaboDrift, a normalization tool for multi-batch metabolomics data.

    Science.gov (United States)

    Thonusin, Chanisa; IglayReger, Heidi B; Soni, Tanu; Rothberg, Amy E; Burant, Charles F; Evans, Charles R

    2017-11-10

    In recent years, mass spectrometry-based metabolomics has increasingly been applied to large-scale epidemiological studies of human subjects. However, the successful use of metabolomics in this context is subject to the challenge of detecting biologically significant effects despite substantial intensity drift that often occurs when data are acquired over a long period or in multiple batches. Numerous computational strategies and software tools have been developed to aid in correcting for intensity drift in metabolomics data, but most of these techniques are implemented using command-line driven software and custom scripts which are not accessible to all end users of metabolomics data. Further, it has not yet become routine practice to assess the quantitative accuracy of drift correction against techniques which enable true absolute quantitation such as isotope dilution mass spectrometry. We developed an Excel-based tool, MetaboDrift, to visually evaluate and correct for intensity drift in a multi-batch liquid chromatography - mass spectrometry (LC-MS) metabolomics dataset. The tool enables drift correction based on either quality control (QC) samples analyzed throughout the batches or using QC-sample independent methods. We applied MetaboDrift to an original set of clinical metabolomics data from a mixed-meal tolerance test (MMTT). The performance of the method was evaluated for multiple classes of metabolites by comparison with normalization using isotope-labeled internal standards. QC sample-based intensity drift correction significantly improved correlation with IS-normalized data, and resulted in detection of additional metabolites with significant physiological response to the MMTT. The relative merits of different QC-sample curve fitting strategies are discussed in the context of batch size and drift pattern complexity. Our drift correction tool offers a practical, simplified approach to drift correction and batch combination in large metabolomics studies

  8. Evaluation in vitro and in vivo of biomimetic hydroxyapatite coated on titanium dental implants

    International Nuclear Information System (INIS)

    Rigo, E.C.S.; Boschi, A.O.; Yoshimoto, M.; Allegrini, S.; Konig, B.; Carbonari, M.J.

    2004-01-01

    Among several materials used as dental implants, metals present relatively high tensile strengths. Although metals are biotolerable, they do not adhere to bone tissues. On the other hand, bioactive ceramics are known to chemically bind to bone tissues, but they are not enough mechanically resistant to tension stresses. To overcome this drawback, biotolerable metals can be coated with bioactive ceramics. Various methods can be employed for coating ceramic layers on metal substrates, among them ion sputtering, plasma spray, sol-gel, electrodeposition and a biomimetic process [E.C.S. Rigo, L.C. Oliveira, L.A. Santos, A.O. Boschi, R.G. Carrodeguas. Implantes metalicos recobertos com hidroxiapatita. Revista de Engenharia Biomedica, vol. 15 (1999), numeros 1-2, 21-29. Rio de Janeiro]. The aim of this work was to study the effect of the substitution of G glass, employed in the conventional biomimetic method during the nucleation stage, by a solution of sodium silicate (SS) on the chemical and morphological characteristics, and the adhesion of biomimetic coatings deposited on Ti implants. The obtained coatings were analyzed by diffuse reflectance FTIR spectroscopy (DRIFT) and scanning electron microscopy (SEM). Titanium implants were immersed in synthetic body fluid (SBF) and SS. All implants were left inside an incubator at 37 deg. C for 7 days, followed by immersion in 1.5 SBF and taken back to the incubator for additional 6 days at 37 deg. C. The 1.5 SBF were refreshed every 2 days. At the end of the treatment, the implants were washed in distilled and deionized water and dried at room temperature. To check the osseointegration, titanium implants coated with biomimetic method were inserted in rabbit's tibia, remaining there for 8 weeks. During the healing period, polyfluorochrome sequential labeling was inoculated in the rabbits to determine the period of bone remodeling. Results from DRIFT and SEM showed that, for all processing variants employed, a HA coating was

  9. Hydrogen high pressure proportional drift detector

    International Nuclear Information System (INIS)

    Arefiev, A.; Balaev, A.

    1983-01-01

    The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

  10. Small-scale lacustrine drifts in Lake Champlain, Vermont

    Science.gov (United States)

    Manley, Patricia L.; Manley, T.O.; Hayo, Kathryn; Cronin, Thomas

    2012-01-01

    High resolution CHIRP (Compressed High Intensity Radar Pulse) seismic profiles reveal the presence of two lacustrine sediment drifts located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments. Drift B sits on a basement high while Drift A is built on a trough-filling acoustically-transparent sediment unit inferred to be a mass-transport event. These drifts are oriented approximately north–south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of upslope asymmetric mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was investigated using Acoustic Doppler Current Profilers (ADCPs) located across Drift A. Sediment cores were taken at the crest and at the edges of the Drift A and were dated. Drift source, deposition, and evolution show that these drifts are formed by a water column shear with the highest deposition occurring along its crest and western flank and began developing circa 8700–8800 year BP.

  11. Spatial and temporal variations of Cocconeis placentula var. euglypta (Ehrenb. 1854 Grunow, 1884 in drift and periphyton

    Directory of Open Access Journals (Sweden)

    EN. Gari

    Full Text Available Spatial and temporal variations of Cocconeis placentula var. euglypta in drift and periphyton were studied in mountain streams of the Córdoba Province (Argentina. The sampling program was conducted in study sites located on a confluence between different order streams during an annual cycle. Samples were also taken every two hours during the daylight period in high and low water conditions. The relationship between drift and cellular reproduction was evaluated by valve length biometrics analysis. C. placentula var. euglypta drift was continuous; its density was not always dependent on periphyton density in each locality. C. placentula var. euglypta drift could be related to abiotic factors such as temperature and flow during the annual cycle. There were significant differences between periphyton and drift valve lengths. Moreover, drift can be associated with cellular reproduction because density was higher when valve lengths were shorter at different hours of the day. C. placentula var. euglypta epiphytims on Cladophora glomerata also influenced drift density and size distribution, modifying the relationship between periphyton and drift during the late spring when C. placentula var. euglypta was detached from senescent mats.

  12. Tabulated In-Drift Geometric and Thermal Properties Used In Drift-Scale Models for TSPA-SR

    International Nuclear Information System (INIS)

    N.D. Francis

    2000-01-01

    The objective of this calculation is to provide in-drift physical properties required by the drift-scale models (both two- and three-dimensional) used in total system performance assessments (TSPA). The physical properties include waste package geometry, waste package thermal properties, emplacement drift geometry including backfill and invert geometry and properties (both thermal and hydrologic), drip shield geometry and thermal properties, all tabulated in a single source

  13. Argus drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Danilov, M; Nagovizin, V; Hasemann, H; Michel, E; Schmidt-Parzefall, W; Wurth, R; Kim, P

    1983-11-15

    The ARGUS detector came into operation at the DORIS-II e/sup +/s/sup -/ storage ring at the end of 1982. Its two meter long drift chamber contains 5940 sense and 24588 field wires organized in uniform 18x18.8 mm/sup 2/ drift cells filling the whole volume. These cells form 36 layers, 18 of which provide stereo views. Each sense wire is equipped with a single hit TDC and ADC for coordinate and dE/dx measurements. The chamber is operated with propane to improve momentum and dE/dx resolution. The drift chamber design and initial performance are presented. With a very crude space-time relation approximation and without all the necessary corrections applied a spatial resolution of about 200 ..mu..m was obtained for half of the drift cell volume. Further corrections should improve this result. An intrinsic dE/dx resolution of 4.2% and an actual resolution of 5% were obtained for cosmic muons and also for Bhabha scattered electrons. An actual dE/dx resolution of 5.6% was obtained for pions from e/sup +/e/sup -/ annihilation data with almost no track selection. A relativistic rise of 30% was observed in good agreement with theory. The long-term stability is still to be investigated.

  14. Continuous corticosterone delivery via the drinking water or pellet implantation: A comparative study in mice.

    Science.gov (United States)

    Gasparini, Sylvia J; Weber, Marie-Christin; Henneicke, Holger; Kim, Sarah; Zhou, Hong; Seibel, Markus J

    2016-12-01

    In order to investigate the effects of glucocorticoid excess in rodent models, reliable methods of continuous glucocorticoid delivery are essential. The current study compares two methods of corticosterone (CS) delivery in regards to their ability to induce typical adverse outcomes such as fat accrual, insulin resistance, sarcopenia and bone loss. Eight-week-old mice received CS for 4weeks either via the drinking water (25-100μgCS/mL) or through weekly surgical implantation of slow release pellets containing 1.5mg CS. Both methods induced abnormal fat mass accrual, inhibited lean mass accretion and bone expansion, suppressed serum osteocalcin levels and induced severe insulin resistance. There was a clear dose dependant relationship between the CS concentrations in the drinking water and the severity of the phenotype, with a concentration of 50μg CS/mL drinking water most closely matching the metabolic changes induced by weekly pellet implantations. In contrast to pellets, however, delivery of CS via the drinking water resulted in a consistent diurnal exposure pattern, closely mimicking the kinetics of clinical glucocorticoid therapy. In addition, the method is safe, inexpensive, easily adjustable, non-invasive and avoids operative stress to the animals. Our data demonstrate that delivery of CS via the drinking water has advantages over weekly implantations of slow-release pellets. A dose of 50μg CS/mL drinking water is appropriate for the investigation of chronic glucocorticoid excess in mice. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  15. Seepage Model for PA Including Drift Collapse

    International Nuclear Information System (INIS)

    Li, G.; Tsang, C.

    2000-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the predictions and analysis performed using the Seepage Model for Performance Assessment (PA) and the Disturbed Drift Seepage Submodel for both the Topopah Spring middle nonlithophysal and lower lithophysal lithostratigraphic units at Yucca Mountain. These results will be used by PA to develop the probability distribution of water seepage into waste-emplacement drifts at Yucca Mountain, Nevada, as part of the evaluation of the long term performance of the potential repository. This AMR is in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (CRWMS M andO 2000 [153447]). This purpose is accomplished by performing numerical simulations with stochastic representations of hydrological properties, using the Seepage Model for PA, and evaluating the effects of an alternative drift geometry representing a partially collapsed drift using the Disturbed Drift Seepage Submodel. Seepage of water into waste-emplacement drifts is considered one of the principal factors having the greatest impact of long-term safety of the repository system (CRWMS M andO 2000 [153225], Table 4-1). This AMR supports the analysis and simulation that are used by PA to develop the probability distribution of water seepage into drift, and is therefore a model of primary (Level 1) importance (AP-3.15Q, ''Managing Technical Product Inputs''). The intended purpose of the Seepage Model for PA is to support: (1) PA; (2) Abstraction of Drift-Scale Seepage; and (3) Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR). Seepage into drifts is evaluated by applying numerical models with stochastic representations of hydrological properties and performing flow simulations with multiple realizations of the permeability field around the drift. The Seepage Model for PA uses the distribution of permeabilities derived from air injection testing in niches and in the cross drift to

  16. Seepage into drifts with mechanical degradation

    International Nuclear Information System (INIS)

    Li, Guomin; Tsang, Chin-Fu

    2002-01-01

    Seepage into drifts in unsaturated tuff is an important issue for the long-term performance of the potential nuclear waste repository at Yucca Mountain, Nevada. Drifts in which waste packages will potentially be emplaced are subject to degradation in the form of rockfall from the drift ceiling induced by stress relief, seismic, or thermal effects. The objective of this study is to calculate seepage rates for various drift-degradation scenarios and for different values of percolation flux for the Topopah Spring middle nonlithophysal (Tptpmn) and the Topopah Spring lower lithophysal (Tptpll) units. Seepage calculations are conducted by (1) defining a heterogeneous permeability model on the drift scale that is consistent with field data, (2) selecting calibrated parameters associated with the Tptpmn and Tptpll units, and (3) simulating seepage on detailed degraded-drift profiles, which were obtained from a separate rock mechanics engineering analysis. The simulation results indicate (1) that the seepage threshold (i.e., the percolation flux at which seepage first occurs) is not significantly changed by drift degradation, and (2) the degradation-induced increase in seepage above the threshold is influenced more by the shape of the cavity created by rockfall than the rockfall volume

  17. Electronics for proportional drift tubes

    International Nuclear Information System (INIS)

    Fremont, G.; Friend, B.; Mess, K.H.; Schmidt-Parzefall, W.; Tarle, J.C.; Verweij, H.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration); Geske, K.; Riege, H.; Schuett, J.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration); Semenov, Y.; CERN-Hamburg-Amsterdam-Rome-Moscow Collaboration)

    1980-01-01

    An electronic system for the read-out of a large number of proportional drift tubes (16,000) has been designed. This system measures deposited charge and drift-time of the charge of a particle traversing a proportional drift tube. A second event can be accepted during the read-out of the system. Up to 40 typical events can be collected and buffered before a data transfer to a computer is necessary. (orig.)

  18. Evolving practices in augmentation operative technique with Sientra HSC round implants.

    Science.gov (United States)

    Calobrace, M Bradley; Kaufman, David L; Gordon, Ashley E; Reid, Dustin L

    2014-07-01

    As of 2012, breast augmentation surgery continues to be the most commonly performed aesthetic surgical procedure in the United States. Surgeons consider a multitude of factors when choosing the type and style of breast implant for a patient. With the continuous evolution of breast implant designs, there are a variety of breast implant options for plastic surgeons to choose from; however, round implants remain the implant of choice for breast augmentation. This article discusses preoperative planning, implant selection, surgical techniques, and postoperative management using Sientra's Silimed brand smooth and textured round implants.

  19. Implementation of drift-flux correlations in ARTIST and its assessment in comparison with THETIS void distribution

    International Nuclear Information System (INIS)

    Yun, B. J.; Kim, H. C.; Moon, S. K.; Lee, W. J.

    1998-01-01

    Non-homogeneous, non-equilibrium drift-flux model was developed in ARTIST code to enhance capability of predicting two-phase flow void distribution at low pressure and low flow conditions. The governing equations of ARTIST code consist of three continuity equations (mixture, liquid, and noncondensibles), two energy equations (gas and mixture) and one mixture momentum equation constituted with the drift-flux model. In order to provide the Co and the Vgj of drift-flux model, four drift-flux correlations, which are Chexal-Lellouche, Ohkawa-Lahey, GE Ramp and Dix models, are implemented. In order to evaluate the accuracy of the drift flux correlations, the steady state void distributions of the THETIS boil-off tests are simulated. The results show that the drift-flux model is quite satisfactory in terms of accuracy and computational efficiency. Among the four drift-flux correlations, the Chexal-Lellouche model showed wide applicability in the prediction of void fraction from low to high pressure condition. Especially, the axial void distribution at low pressure and low flow is far better than those of both the two-fluid model of RELAP5/MOD3 code and the homogeneous model. Thus, the drift-flux model of the ARTIST code can be used as an efficient tool in predicting the void distribution of two-phase flow at low pressure and low flow conditions

  20. [Silastic implant and synovitis].

    Science.gov (United States)

    Sennwald, G

    1989-07-22

    The silastic implant based on siloxane polymere induces granulomatous synovitis in certain predisposed individuals, a reaction which may continue even after removal of the implant. This is also true of a prosthesis of the trapezium in two of our patients, though to a lesser degree. This is probably the reason why the problem has not yet been widely recognized. The hypothesis is put forward that an enzymatic predisposition may allow chemical degradation of the fragmented silastic implant into a toxic component responsible for the pathologic condition. The slow progression of the lesions is a challenge for the future and puts in question the further use of silastic implants.

  1. The launching and propagation of drift waves in a steady-state plasma

    International Nuclear Information System (INIS)

    Sandeman, J.; Elliott, J.A.; Sutcliffe, M.; Rusbridge, M.G.

    1992-01-01

    The UMIST linear quadrupole GOLUX is a steady-state device in which hydrogen plasma is continuously injected axially, at one end, from an external duoplasmatron source. The electron temperature in the drift wave region is about 1 eV, and the density about 10 15 m -3 . Self-excited intrinsic drift modes are observed in the shared flux region of GOLUX, forming a broad band between 30 and 50 kHz. Drift waves may also be launched into the system, by passing an AC current through the plasma between the two flag antennae. These coherent launched waves present a powerful means of studying drift wave phenomena. We obtain information about the launched wave by detecting both density and potential fluctuations, using a small cylindrical Langmuir probe and lock-in amplifier techniques. Scanning the probe in the longitudinal (z) direction yields the spatial variation of amplitude and phase with respect to the launching signal; the ratio of the wave potential, extrapolated back to the probe, to the launching current gives the launching impedance, a measure of the effectiveness of the launching process. (author) 5 refs., 6 figs

  2. Lifetime control of the minority carrier in PiN diodes by He+ ion implantation

    International Nuclear Information System (INIS)

    Tanaka, Y.; Kojima, K.; Takao, K.; Okamoto, M.; Kawasaki, M.; Takatsuka, A.; Yatsuo, T.; Arai, K.

    2005-01-01

    This paper reports the first demonstration of the lifetime control of the minority carrier in 4H-SiC PiN diodes by He + ion implantation. In this work, we fabricated 4H-SiC PiN diodes with the epitaxial junction and the blocking voltage of 2.6 kV, precisely corresponding to the theoretical blocking voltage calculated from the doping concentration (4.0 x 10 15 /cm 2 ) and the thickness of the drift layer (16.5 μm). He + ion implantation was performed with the energy and the dose of 400 kV and 1.0 x 10 13 -2.0 x 10 14 /cm 2 , respectively. We observed no different characteristics in the blocking voltage (2.6kV) and leakage current ( + ion implantation. However, we confirmed the improvement of the current recovery characteristics in the diodes with He + ion implantation. (orig.)

  3. Nitrogen implantation in steel with an impulsive ion implanter

    International Nuclear Information System (INIS)

    Feugeas, J.N.; Gonzalez, C.O.; Hermida, J.; Nieto, M.; Peyronel, M.F.; Sanchez, G.

    1990-01-01

    This work describes the results of steel implantation with nitrogen, with a pulsed accelerator which provides a continuous ion energy spectrum giving a uniform profile of nitrogen without changing its operative conditions. (Author)

  4. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.

    2002-10-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  5. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.; Matsuoka, K.; Nakajima, N.; Itoh, S.-I.; Neilson, G.H.; Zarnstorff, M.C.; Rewoldt, G.

    2003-01-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  6. 21 CFR 872.3645 - Subperiosteal implant material.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3645 Subperiosteal implant material. (a) Identification. Subperiosteal implant material is a device composed of titanium or cobalt chrome molybdenum... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Subperiosteal implant material. 872.3645 Section...

  7. Calibration of the CMS Drift Tube Chambers and Measurement of the Drift Velocity with Cosmic Rays

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Nysten, J; Tuominen, E; Tuominiemi, J; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Nedelec, P; Sillou, D; Besancon, M; Chipaux, R; Dejardin, M; Denegri, D; Descamps, J; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Lemaire, M C; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Rousseau, D; Titov, M; Verrecchia, P; Baffioni, S; Bianchini, L; Bluj, M; Busson, P; Charlot, C; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Paganini, P; Sirois, Y; Thiebaux, C; Zabi, A; Agram, J L; Besson, A; Bloch, D; Bodin, D; Brom, J M; Conte, E; Drouhin, F; Fontaine, J C; Gelé, D; Goerlach, U; Gross, L; Juillot, P; Le Bihan, A C; Patois, Y; Speck, J; Van Hove, P; Baty, C; Bedjidian, M; Blaha, J; Boudoul, G; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; Dupasquier, T; El Mamouni, H; Fassi, F; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Lumb, N; Mirabito, L; Perries, S; Vander Donckt, M; Verdier, P; Djaoshvili, N; Roinishvili, N; Roinishvili, V; Amaglobeli, N; Adolphi, R; Anagnostou, G; Brauer, R; Braunschweig, W; Edelhoff, M; Esser, H; Feld, L; Karpinski, W; Khomich, A; Klein, K; Mohr, N; Ostaptchouk, A; Pandoulas, D; Pierschel, G; Raupach, F; Schael, S; Schultz von Dratzig, A; Schwering, G; Sprenger, D; Thomas, M; Weber, M; Wittmer, B; Wlochal, M; Actis, O; Altenhöfer, G; Bender, W; Biallass, P; Erdmann, M; Fetchenhauer, G; Frangenheim, J; Hebbeker, T; Hilgers, G; Hinzmann, A; Hoepfner, K; Hof, C; Kirsch, M; Klimkovich, T; Kreuzer, P; Lanske, D; Merschmeyer, M; Meyer, A; Philipps, B; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Sowa, M; Steggemann, J; Szczesny, H; Teyssier, D; Zeidler, C; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Hermanns, T; Heydhausen, D; Kalinin, S; Kress, T; Linn, A; Nowack, A; Perchalla, L; Poettgens, M; Pooth, O; Sauerland, P; Stahl, A; Tornier, D; Zoeller, M H; Aldaya Martin, M; Behrens, U; Borras, K; Campbell, A; Castro, E; Dammann, D; Eckerlin, G; Flossdorf, A; Flucke, G; Geiser, A; Hatton, D; Hauk, J; Jung, H; Kasemann, M; Katkov, I; Kleinwort, C; Kluge, H; Knutsson, A; Kuznetsova, E; Lange, W; Lohmann, W; Mankel, R; Marienfeld, M; Meyer, A B; Miglioranzi, S; Mnich, J; Ohlerich, M; Olzem, J; Parenti, A; Rosemann, C; Schmidt, R; Schoerner-Sadenius, T; Volyanskyy, D; Wissing, C; Zeuner, W D; Autermann, C; Bechtel, F; Draeger, J; Eckstein, D; Gebbert, U; Kaschube, K; Kaussen, G; Klanner, R; Mura, B; Naumann-Emme, S; Nowak, F; Pein, U; Sander, C; Schleper, P; Schum, T; Stadie, H; Steinbrück, G; Thomsen, J; Wolf, R; Bauer, J; Blüm, P; Buege, V; Cakir, A; Chwalek, T; De Boer, W; Dierlamm, A; Dirkes, G; Feindt, M; Felzmann, U; Frey, M; Furgeri, A; Gruschke, J; Hackstein, C; Hartmann, F; Heier, S; Heinrich, M; Held, H; Hirschbuehl, D; Hoffmann, K H; Honc, S; Jung, C; Kuhr, T; Liamsuwan, T; Martschei, D; Mueller, S; Müller, Th; Neuland, M B; 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Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    This paper describes the calibration procedure for the drift tubes of the CMS barrel muon system and reports the main results obtained with data collected during a high statistics cosmic ray data-taking period. The main goal of the calibration is to determine, for each drift cell, the minimum time delay for signals relative to the trigger, accounting for the drift velocity within the cell. The accuracy of the calibration procedure is influenced by the random arrival time of cosmic muons. A more refined analysis of the drift velocity was performed during the offline reconstruction phase, which takes into account this feature of cosmic ray events.

  8. Comparison of electrostatic and electromagnetic synchronization of drift waves and suppression of drift wave turbulence in a linear device

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, C; Grulke, O; Klinger, T, E-mail: christian.brandt@lpmi.uhp-nancy.f [Max-Planck-Institute for Plasma Physics, EURATOM Association, Wendelsteinstrasse 1, D-17491 Greifswald (Germany)

    2010-05-15

    Experiments in a cylindrical magnetized plasma on the control of drift waves by means of two different spatiotemporal open-loop control systems-an electrostatic and an electromagnetic exciter-are reported. The drift wave dynamics is controlled by a mode-selective signal created with azimuthal arrangements of eight electrodes and eight saddle coils, respectively. Nonlinear interaction between the control signals and drift waves is observed, leading to synchronization of coherent drift waves and suppression of broadband drift wave turbulence. The cross-phase between density and potential fluctuations reduces from {approx}{pi}/2 in turbulence to {approx}0 in controlled turbulence. Hence, the cross-field transport is reduced to the level of coherent drift waves. For both control systems the coupling to the drift wave can be ascribed to the drive of parallel currents, on the one hand via direct electric contact and, on the other hand, via electromagnetic induction.

  9. Drift chamber data readout system

    International Nuclear Information System (INIS)

    Basiladze, S.G.; Lokhonyai, L.

    1980-01-01

    An electronic system for processing drift chamber signals is described. The system consists of 4-channel fast amplifier-discriminators of low threshold, 16-channel time-expanders transforming 0.5 μs time intervals to 10 μs and a 9-bit time-to-digital converter (TDC) recording up to 16 expanded time intervals. If the average track multiplicity is small, TDC is capable to process signals from 4 time-expanders (i.e., 64 drift gaps). In order to record multiple tracks per drift gap discriminator outputs can be connected to a number of time-expander channels. The fast clear input enables the system to be cleared within 0.5 μs. Efficient readout from TDC is facilated by reading only those channels which contain non-zero data (9 bits - drift time; 6 bits - wire number)

  10. Ion implantation for microelectronics

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1977-01-01

    Ion implantation has proved to be a versatile and efficient means of producing microelectronic devices. This review summarizes the relevant physics and technology and assesses the advantages of the method. Examples are then given of widely different device structures which have been made by ion implantation. While most of the industrial application has been in silicon, good progress continues to be made in the more difficult field of compound semiconductors. Equipment designed for the industrial ion implantation of microelectronic devices is discussed briefly. (Auth.)

  11. Effects of continual intermittent administration of parathyroid hormone on implant stability in the presence of osteoporosis: an in vivo study using resonance frequency analysis in a rabbit model

    Directory of Open Access Journals (Sweden)

    Yoshifumi Oki

    Full Text Available Abstract Objective: This study aimed to evaluate the effects of continual intermittent administration of parathyroid hormone (PTH on implant stability in the presence of osteoporosis, using rabbit models. Material and Methods: Fifteen female New Zealand white rabbits underwent ovariectomy and were administered glucocorticoids to induce osteoporosis, following which they were divided into three groups. The first group received intermittent subcutaneous PTH for 4 weeks until implant placement (PTH1, while the second and third groups received PTH (PTH2 and saline (control, respectively, for 4 weeks before and after implant placement. After intermittent administration of PTH or saline, titanium implants were inserted into the left femoral epiphyses of all animals, and the implant stability quotient (ISQ was measured immediately after placement to assess the primary stability and at 2 and 4 weeks after implant placement to assess osseointegration. At 4 weeks after implant placement, histological and histomorphometric evaluations were conducted and the bone area around the implant socket was measured as a ratio of the total bone area to the total tissue area. Results: Regarding primary stability, the ISQ values for the PTH1 and PTH2 groups were significantly higher than those for the control group (p<0.05. Concerning osseointegration, the ISQ values at 2 and 4 weeks were significantly higher for the PTH2 group than for the PTH1 and control (p<0.05 groups. Histological assessments showed a thicker and more trabecular bone around the implant sockets in the PTH2 specimens than in the PTH1 and control specimens. The bone area around the implant socket was significantly greater in the PTH2 group than in the PTH1 and control groups (p<0.05. Conclusions: Our results suggest that continual intermittent PTH administration before and after dental implant placement is effective for the achievement of favorable stability and osseointegration in the presence of

  12. An electrodeless drift chamber

    International Nuclear Information System (INIS)

    Allison, J.; Barlow, R.J.; Bowdery, C.K.; Duerdoth, I.; Rowe, P.G.

    1982-01-01

    We describe a chamber in which the drift field is controlled by the deposition of electrostatic charge on an insulating surface. The chamber operates with good efficiency and precision for observed drift distances of up to 45 cm, promises to be extremely robust and adaptable and offers a very cheap way of making particle detectors. (orig.)

  13. Implantable enzyme amperometric biosensors.

    Science.gov (United States)

    Kotanen, Christian N; Moussy, Francis Gabriel; Carrara, Sandro; Guiseppi-Elie, Anthony

    2012-05-15

    The implantable enzyme amperometric biosensor continues as the dominant in vivo format for the detection, monitoring and reporting of biochemical analytes related to a wide range of pathologies. Widely used in animal studies, there is increasing emphasis on their use in diabetes care and management, the management of trauma-associated hemorrhage and in critical care monitoring by intensivists in the ICU. These frontier opportunities demand continuous indwelling performance for up to several years, well in excess of the currently approved seven days. This review outlines the many challenges to successful deployment of chronically implantable amperometric enzyme biosensors and emphasizes the emerging technological approaches in their continued development. The foreign body response plays a prominent role in implantable biotransducer failure. Topics considering the approaches to mitigate the inflammatory response, use of biomimetic chemistries, nanostructured topographies, drug eluting constructs, and tissue-to-device interface modulus matching are reviewed. Similarly, factors that influence biotransducer performance such as enzyme stability, substrate interference, mediator selection and calibration are reviewed. For the biosensor system, the opportunities and challenges of integration, guided by footprint requirements, the limitations of mixed signal electronics, and power requirements, has produced three systems approaches. The potential is great. However, integration along the multiple length scales needed to address fundamental issues and integration across the diverse disciplines needed to achieve success of these highly integrated systems, continues to be a challenge in the development and deployment of implantable amperometric enzyme biosensor systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. In-Drift Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    D. Jolley

    2000-11-09

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

  15. In-Drift Microbial Communities

    International Nuclear Information System (INIS)

    Jolley, D.

    2000-01-01

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses

  16. Dissipative drift instability in dusty plasma

    Directory of Open Access Journals (Sweden)

    Nilakshi Das

    2012-03-01

    Full Text Available An investigation has been done on the very low-frequency electrostatic drift waves in a collisional dusty plasma. The dust density gradient is taken perpendicular to the magnetic field B0⃗, which causes the drift wave. In this case, low-frequency drift instabilities can be driven by E1⃗×B0⃗ and diamagnetic drifts, where E1⃗ is the perturbed electric field. Dust charge fluctuation is also taken into consideration for our study. The dust- neutral and ion-neutral collision terms have been included in equations of motion. It is seen that the low-frequency drift instability gets damped in such a system. Both dust charging and collision of plasma particles with the neutrals may be responsible for the damping of the wave. Both analytical and numerical techniques have been used while developing the theory.

  17. Single nozzle spray drift measurements of drift reducing nozzles at two forward speeds

    NARCIS (Netherlands)

    Stallinga, H.; Zande, van de J.C.; Michielsen, J.G.P.; Velde, van P.

    2016-01-01

    In 2011‒2012 single nozzle field experiments were carried out to determine the effect of different flat fan spray nozzles of the spray drift reduction classes 50, 75, 90 and 95% on spray drift at two different forward speeds (7.2 km h-1 and 14.4 km h-1). Experiments were performed with a single

  18. Drift Chambers detectors; Detectores de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I; Martinez laso, L

    1989-07-01

    We present here a review of High Energy Physics detectors based on drift chambers. The ionization, drift diffusion, multiplication and detection principles are described. Most common drift media are analysed, and a classification of the detectors according to its geometry is done. Finally the standard read-out methods are displayed and the limits of the spatial resolution are discussed. (Author) 115 refs.

  19. Drift mechanism for energetic charged particles at shocks

    International Nuclear Information System (INIS)

    Webb, G.M.; Axford, W.I.; Terasawa, T.

    1983-01-01

    The energy changes of energetic charged particles at a plane shock due to the so-called drift mechanism are analyzed by using the ''adiabatic treatment.'' The analysis shows that for a fast MHD shock, particles lose energy owing to acceleration (curvature) drift in the magnetic field at the shock with the drift velocity being antiparallel to the electric field, and they gain energy owing to gradient drift parallel to the electric field. It is shown that particles with pitch angles aligned along the magnetic field which pass through the shock tend to lose energy owing to acceleration drift, whereas particles with pitch angles nonaligned to the magnetic field gain energy owing to gradient drift. Particles that are reflected by the shock always gain energy. Slow-mode shocks may be similarly analyzed, but in this case curvature drifts give rise to particle energy gains, and gradient drifts result in particle energy losses

  20. IN DRIFT CORROSION PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  1. Ion implantation for semiconductors

    International Nuclear Information System (INIS)

    Grey-Morgan, T.

    1995-01-01

    Full text: Over the past two decades, thousands of particle accelerators have been used to implant foreign atoms like boron, phosphorus and arsenic into silicon crystal wafers to produce special embedded layers for manufacturing semiconductor devices. Depending on the device required, the atomic species, the depth of implant and doping levels are the main parameters for the implantation process; the selection and parameter control is totally automated. The depth of the implant, usually less than 1 micron, is determined by the ion energy, which can be varied between 2 and 600 keV. The ion beam is extracted from a Freeman or Bernas type ion source and accelerated to 60 keV before mass analysis. For higher beam energies postacceleration is applied up to 200 keV and even higher energies can be achieved by mass selecting multiplycharged ions, but with a corresponding reduction in beam output. Depending on the device to be manufactured, doping levels can range from 10 10 to 10 15 atoms/cm 2 and are controlled by implanter beam currents in the range up to 30mA; continuous process monitoring ensures uniformity across the wafer of better than 1 % . As semiconductor devices get smaller, additional sophistication is required in the design of the implanter. The silicon wafers charge electrically during implantation and this charge must be dissipated continuously to reduce the electrical stress in the device and avoid destructive electrical breakdown. Electron flood guns produce low energy electrons (below 10 electronvolts) to neutralize positive charge buildup and implanter design must ensure minimum contamination by other isotopic species and ensure low internal sputter rates. The pace of technology in the semiconductor industry is such that implanters are being built now for 256 Megabit circuits but which are only likely to be widely available five years from now. Several specialist companies manufacture implanter systems, each costing around US$5 million, depending on the

  2. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices intended...

  3. Intrafractional Baseline Shift or Drift of Lung Tumor Motion During Gated Radiation Therapy With a Real-Time Tumor-Tracking System

    International Nuclear Information System (INIS)

    Takao, Seishin; Miyamoto, Naoki; Matsuura, Taeko; Onimaru, Rikiya; Katoh, Norio; Inoue, Tetsuya; Sutherland, Kenneth Lee; Suzuki, Ryusuke; Shirato, Hiroki; Shimizu, Shinichi

    2016-01-01

    Purpose: To investigate the frequency and amplitude of baseline shift or drift (shift/drift) of lung tumors in stereotactic body radiation therapy (SBRT), using a real-time tumor-tracking radiation therapy (RTRT) system. Methods and Materials: Sixty-eight patients with peripheral lung tumors were treated with SBRT using the RTRT system. One of the fiducial markers implanted near the tumor was used for the real-time monitoring of the intrafractional tumor motion every 0.033 seconds by the RTRT system. When baseline shift/drift is determined by the system, the position of the treatment couch is adjusted to compensate for the shift/drift. Therefore, the changes in the couch position correspond to the baseline shift/drift in the tumor motion. The frequency and amount of adjustment to the couch positions in the left-right (LR), cranio-caudal (CC), and antero-posterior (AP) directions have been analyzed for 335 fractions administered to 68 patients. Results: The average change in position of the treatment couch during the treatment time was 0.45 ± 2.23 mm (mean ± standard deviation), −1.65 ± 5.95 mm, and 1.50 ± 2.54 mm in the LR, CC, and AP directions, respectively. Overall the baseline shift/drift occurs toward the cranial and posterior directions. The incidence of baseline shift/drift exceeding 3 mm was 6.0%, 15.5%, 14.0%, and 42.1% for the LR, CC, AP, and for the square-root of sum of 3 directions, respectively, within 10 minutes of the start of treatment, and 23.0%, 37.6%, 32.5%, and 71.6% within 30 minutes. Conclusions: Real-time monitoring and frequent adjustments of the couch position and/or adding appropriate margins are suggested to be essential to compensate for possible underdosages due to baseline shift/drift in SBRT for lung cancers.

  4. Characteristics of shock-associated fast-drift kilometric radio bursts

    Science.gov (United States)

    Macdowall, R. J.; Kundu, M. R.; Stone, R. G.

    1987-01-01

    The existence of a class of fast-drift, shock-associated (SA), kilometric radio bursts which occur at the time of metric type II emission and which are not entirely the kilometric continuation of metric type III bursts has been reported previously (Cane et al., 1981). In this paper unambiguous SA event criteria are established for the purpose of statistically comparing SA events with conventional kilometric type III bursts. Applying these criteria to all long-duration, fast-drift bursts observed by the ISEE-3 spacecraft during a 28-month interval, it is found that more than 70 percent of the events satisfying the criteria are associated with the radio signatures of coronal shocks. If a given event is associated with a metric type II or type IV burst, it is 13 times more likely to satisfy the SA criteria than an event associated only with metric type III activity.

  5. Analytic solution of the potential and electric field of a jet type drift chamber

    Energy Technology Data Exchange (ETDEWEB)

    Weltin, A

    1988-02-15

    Starting from the known two-dimensional potential of a multiwire proportional chamber, the analytic expressions of the potential and the electric field are derived for a jet type drift chamber with a central wire plane of alternating sense and potential wires. The design goal of any jet chamber, namely the periodicity of the electric drift field, is imposed as a boundary condition at the beginning. In this way, the formulae are short and can be easily evaluated. In particular, expressions are given for the mean potential of the central wire plane, the drift field and the wire surface fields. Moreover, wire cathodes frequently used in jet chambers are described by analytic expressions. For a given drift field the difference of the potential as compared to a continuous metal cathode is presented. These results allowed to construct a two-dimensional computer simulation of the full OPAL jet chamber with no explicit periodicity but all its boundaries. Using field shaping electrodes a geometrically short yet quite satisfactory termination of a sense wire plane is demonstrated. Finally an example is presented, which is calculated in detail.

  6. Implementation of drift-flux model in artist and assessment to thetis void distribution

    International Nuclear Information System (INIS)

    Kim, H. C.; Yun, B. J.; Moon, S. K.; Jeong, J. J.; Lee, W. J.

    1998-01-01

    A system transient analysis code, ARTIST, based on the drift-flux model is being developed to enhance capability of predicting two-phase flow void distribution at low pressure and low flow conditions. The governing equations of the ARTIST code consist of three continuity equations (mixture, liquid, and noncondensibles), two energy equations (gas and mixture) and one mixture momentum euqation constituted with the drift-flux model. Area averaged one-dimensional conservation equations are established using the flow quality expressed in terms of the relative velocity. The relative velocity is obtained from the drift flux relationship. The Chexal-Lellouche void fraction correlation is used to provide the drift velocity and the concentration parameter. The implicit one-step method and the block elimination technique are employed as numerical solution scheme for the node-flowpath thermal-hydraulic network. In order to validate the ARIST code, the steady state void distributions of the THETIS boil-off tests are simulated. The axial void distributions calculated by the Chexal-Lellouche fraction correlation at low pressure and low flow are better than those of both the two-fluid model of RELAP5/MOD3 code and the homogeneous model. The drift-flux model of the ARTIST code is an efficient tool in predicting the void distribution of two-phase flow at low pressure and low flow condtions

  7. Right ventricular failure after implantation of a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Cordtz, Johan Joakim; Nilsson, Jens C; Hansen, Peter B

    2014-01-01

    Right ventricular failure (RVF) is a significant complication after implantation of a left ventricular assist device. We aimed to identify haemodynamic changes in the early postoperative phase that predicted subsequent development of RVF in a cohort of HeartMate II (HMII) implanted patients....

  8. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  9. 21 CFR 872.3630 - Endosseous dental implant abutment.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant abutment. 872.3630... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3630 Endosseous dental implant abutment. (a) Identification. An endosseous dental implant abutment is a premanufactured prosthetic component...

  10. Role of drifts in diffusive shock acceleration

    International Nuclear Information System (INIS)

    Decker, R.B.

    1988-01-01

    The role played by shock-associated drifts during the diffusive acceleration of charged particles at collisionless MHD shocks is evaluated. In the rest frame of the shock, the total energy gained by a particle is shown to result from two coupled acceleration mechanisms, the usual first-order Fermi mechanism and the drift mechanism. When averaged over a distribution of particles, the ratio of the drift-associated energy gain to the total energy is found to be independent of the total energy at a given theta1 (the angle between the shock normal and the unperturbed upstream magnetic field) in agreement with theoretical predictions. No evidence is found for drift-associated deceleration, suggesting that drifts always augment acceleration. 35 references

  11. TBV 361 RESOLUTION ANALYSIS: EMPLACEMENT DRIFT ORIENTATION

    International Nuclear Information System (INIS)

    Lin, M.; Kicker, D.C.; Sellers, M.D.

    1999-01-01

    The purpose of this To Be Verified/To Be Determined (TBX) resolution analysis is to release ''To Be Verified'' (TBV)-361 related to the emplacement drift orientation. The system design criterion in ''Subsurface Facility System Description Document'' (CRWMS M andO 1998a, p.9) specifies that the emplacement drift orientation relative to the dominant joint orientations should be at least 30 degrees. The specific objectives for this analysis include the following: (1) Collect and evaluate key block data developed for the repository host horizon rock mass. (2) Assess the dominant joint orientations based on available fracture data. (3) Document the maximum block size as a function of drift orientation. (4) Assess the applicability of the drift orientation/joint orientation offset criterion in the ''Subsurface Facility System Description Document'' (CRWMS M andO 1998a, p.9). (5) Consider the effects of seepage on drift orientation. (6) Verify that the viability assessment (VA) drift orientation complies with the drift orientation/joint orientation offset criterion, or provide justifications and make recommendations for modifying the VA emplacement drift layout. In addition to providing direct support to the System Description Document (SDD), the release of TBV-361 will provide support to the Repository Subsurface Design Department. The results from this activity may also provide data and information needs to support the MGR Requirements Department, the MGR Safety Assurance Department, and the Performance Assessment Organization

  12. Elders with implant overdentures: a 22-year clinical report.

    Science.gov (United States)

    Alsabeeha, Nabeel H M

    2012-09-01

    To report on the long-term survival and prosthodontic maintenance of two edentulous adults with mandibular overdentures supported by hydroxyapatite (HA)-coated implants. Mandibular implant overdentures are a successful treatment option with positive impact on the quality of life of elderly edentulous adults. Long-term survival of the implants requires continued rigorous prosthodontic maintenance. Two elderly edentulous adults with mandibular overdentures supported by 2 HA-coated implants were presented for prosthodontic rehabilitation after 22 years of placement. The implants were osseo-integrated and surviving at presentation based on accepted criteria. The mandibular implant overdentures suffered recurrent loss of retention and stability. Prosthodontic treatment involving the replacement of defective attachment systems and construction of new sets of mandibular implant overdentures opposing complete maxillary dentures is presented. The long-term survival of mandibular 2-implant overdentures requires continued prosthodontic maintenance. A conservative approach in the rehabilitation of two older edentulous adults with mandibular 2-implant overdentures was described including proper selection of attachment systems. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

  13. Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant. [Transport of drift-derived chromium in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, F.G.; Hanna, S.R.; Parr, P.D.

    1979-01-01

    The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant.

  14. Precision alignment of permanent-magnet drift tubes

    International Nuclear Information System (INIS)

    Liska, D.J.; Dauelsberg, L.B.; Spalek, G.

    1986-01-01

    The Lawrence Berkeley National Laboratory (LBNL) technique of drift-tube alignment has been resurrected at Los Alamos for the precision alignment of 1-cm-bore drift tubes that carry high-gradient rare-earth-cobalt quadrupole. Because the quadrupole cannot be switched off, this technique is not applicable to a drift-tube assembly, but tests indicate that individual magnetic centers can be detected with a precision of +- 0.003 mm. Methods of transferring this information to machined alignment flats on the sides of the drift-tube body are discussed. With measurements of drift tubes designed for a 100-mA. 425-MHz drift-tube linac, we have detected offsets between the geometric and magnetic axes of up to +- 0.05 mm following final assembly and welding. This degree of offset is serious if not accommodated, because it represents the entire alignment tolerance for the 40-cell tank. The measurement equipment and technique are described

  15. Cooling tower drift: comprehensive case study

    International Nuclear Information System (INIS)

    Laulainen, N.S.; Ulanski, S.L.

    1979-01-01

    A comprehensive experiment to study drift from mechanical drift cooling towers was conducted during June 1978 at the PG and E Pittsburg Power Plant. The data from this study will be used for validation of drift deposition models. Preliminary results show the effects of tower geometry and orientation with respect to the wind and to single- or two-tower operation. The effect of decreasing relative humidity during a test run can also be seen

  16. Variable-energy drift-tube linacs

    International Nuclear Information System (INIS)

    Swenson, D.A.; Boyd, T.J. Jr.; Potter, J.M.; Stovall, J.E.

    1982-01-01

    Practical applications of ion linacs are more viable now than ever before because of the recent development of the radio-frequency quadrupole accelerating structure, as well as other technological advances developed under the Pion Generator for Medical Irradiations program. This report describes a practical technique for varying the energy of drift-tube linacs and thus further broadening the possibilities for linac applications. This technique involves using the post couplers (normally used to flatten and stabilize the electric fields) to create a step in the fields, thus terminating the acceleration process. In the examples given for a 70-MeV accelerator design, when using this technique the energy is continually variable down to 20 MeV, while maintaining a small energy spread

  17. Implantation doping of GaN

    International Nuclear Information System (INIS)

    Zolper, J.C.

    1996-01-01

    Ion implantation has played an enabling role in the realization of many high performance photonic and electronic devices in mature semiconductor materials systems such as Si and GaAs. This can also be expected to be the case in III-Nitride based devices as the material quality continues to improve. This paper reviews the progress in ion implantation processing of the III-Nitride materials, namely, GaN, AlN, InN and their alloys. Details are presented of the successful demonstrations of implant isolation as well as n- and p-type implantation doping of GaN. Implant doping has required activation annealing at temperatures in excess of 1,000 C. The nature of the implantation induced damage and its response to annealing is addressed using Rutherford Backscattering. Finally, results are given for the first demonstration of a GaN device fabricated using ion implantation doping, a GaN junction field effect transistor (JFET)

  18. Progress in semiconductor drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Walton, J.; Gatti, E.

    1985-01-01

    Progress in testing semiconductor drift detectors is reported. Generally better position and energy resolutions were obtained than resolutions published previously. The improvement is mostly due to new electronics better matched to different detectors. It is shown that semiconductor drift detectors are becoming versatile and reliable detectors for position and energy measurements

  19. Electron injection in semiconductor drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Castoldi, A.; Vacchi, A.

    1990-01-01

    The paper reports the first successful results of a simple MOS structure to inject electrons at a given position in Silicon Drift Detectors. The structure allows on-line calibration of the drift velocity of electrons within the detector. The calibration is a practical method to trace the temperature dependence of the electron mobility. Several of these injection structures can be implemented in silicon drift detectors without additional steps in the fabrication process. 5 refs., 11 figs

  20. World in the drift-ice; Ryuhyo no sekai

    Energy Technology Data Exchange (ETDEWEB)

    Aota, M. [Hokkaido Univ., Hokkaido (Japan)

    1999-06-07

    What freezes in the sea in the circumference in our country is only Sea of Okhotsk. What will be the drift-ice for the people who live in this beach? The distress by the drift-ice often occurred. The drift-ice spoils tearing, shell in the pickpocket in respect of the fishing gear in respect of destruction and kelp. The boat was landed, when the drift-ice came, the fisherman came out, and it went to the labor. The seafood processing field becomes also the closure condition. The drift-ice was a white demon for people of the beach, and it was a troublesome person. In the meantime, the drift-ice soothes the wave, and it becomes a natural float breakwater, the coast is kept, and the salt damage does be held. There is some that it is faced the sea off beach cleaning. People of the seashore in Okohtsk live with the drift-ice with merits and both demerit sideses. (NEDO)

  1. Ground Control for Emplacement Drifts for LA

    International Nuclear Information System (INIS)

    Y. Sun

    2004-01-01

    The purpose of this calculation is to analyze the stability of repository emplacement drifts during the preclosure period, and to provide a final ground support method for emplacement drifts for the License Application (LA). The scope of the work includes determination of input parameter values and loads, selection of appropriate process and methods for the calculation, application of selected methods, such as empirical or analytical, to the calculation, development and execution of numerical models, and evaluation of results. Results from this calculation are limited to use for design of the emplacement drifts and the final ground support system installed in these drifts. The design of non-emplacement openings and their ground support systems is covered in the ''Ground Control for Non-Emplacement Drifts for LA'' (BSC 2004c)

  2. MUON DETECTOR: BARREL DRIFT TUBES (DT) AND ALIGNMENT

    CERN Multimedia

    Marco Dallavalle

    After months of cosmics data taking the drift tube (DT) detector is in good shape, ready for LHC beams. Several hundreds of millions of cosmics events have been recorded; out of those, more than 90% were triggered by the DT system. Data integrity analyses have shown a very reliable read-out system, also during high rate tests. With a 98% of the detector operational, only awaiting the arrival of some low voltage modules and for the completion of the DT Track Finder system, data taking is starting to become routine job. These continuous running exercises have been very useful to study performance and reliability of the detector in a medium term period, allowing understanding and fixing failures that have occurred with low frequency. Drift tubes have become a very stable system, becoming a service of muon triggering for the tracker after its final installation. During the last months, major efforts have taken place in synchronization tasks, within the DT system (250 chambers) and also with the rest of the CMS su...

  3. Drift-Scale THC Seepage Model

    International Nuclear Information System (INIS)

    C.R. Bryan

    2005-01-01

    The purpose of this report (REV04) is to document the thermal-hydrologic-chemical (THC) seepage model, which simulates the composition of waters that could potentially seep into emplacement drifts, and the composition of the gas phase. The THC seepage model is processed and abstracted for use in the total system performance assessment (TSPA) for the license application (LA). This report has been developed in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2005 [DIRS 172761]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this report. The plan for validation of the models documented in this report is given in Section 2.2.2, ''Model Validation for the DS THC Seepage Model,'' of the TWP. The TWP (Section 3.2.2) identifies Acceptance Criteria 1 to 4 for ''Quantity and Chemistry of Water Contacting Engineered Barriers and Waste Forms'' (NRC 2003 [DIRS 163274]) as being applicable to this report; however, in variance to the TWP, Acceptance Criterion 5 has also been determined to be applicable, and is addressed, along with the other Acceptance Criteria, in Section 4.2 of this report. Also, three FEPS not listed in the TWP (2.2.10.01.0A, 2.2.10.06.0A, and 2.2.11.02.0A) are partially addressed in this report, and have been added to the list of excluded FEPS in Table 6.1-2. This report has been developed in accordance with LP-SIII.10Q-BSC, ''Models''. This report documents the THC seepage model and a derivative used for validation, the Drift Scale Test (DST) THC submodel. The THC seepage model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC submodel uses a drift

  4. Spin drift and spin diffusion currents in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

    2008-09-15

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  5. Spin drift and spin diffusion currents in semiconductors

    Directory of Open Access Journals (Sweden)

    M Idrish Miah

    2008-01-01

    Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  6. Spin drift and spin diffusion currents in semiconductors

    International Nuclear Information System (INIS)

    Idrish Miah, M

    2008-01-01

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  7. Drift chamber tracking with neural networks

    International Nuclear Information System (INIS)

    Lindsey, C.S.; Denby, B.; Haggerty, H.

    1992-10-01

    We discuss drift chamber tracking with a commercial log VLSI neural network chip. Voltages proportional to the drift times in a 4-layer drift chamber were presented to the Intel ETANN chip. The network was trained to provide the intercept and slope of straight tracks traversing the chamber. The outputs were recorded and later compared off line to conventional track fits. Two types of network architectures were studied. Applications of neural network tracking to high energy physics detector triggers is discussed

  8. Dike Propagation Near Drifts

    International Nuclear Information System (INIS)

    2002-01-01

    The purpose of this Analysis and Model Report (AMR) supporting the Site Recommendation/License Application (SR/LA) for the Yucca Mountain Project is the development of elementary analyses of the interactions of a hypothetical dike with a repository drift (i.e., tunnel) and with the drift contents at the potential Yucca Mountain repository. This effort is intended to support the analysis of disruptive events for Total System Performance Assessment (TSPA). This AMR supports the Process Model Report (PMR) on disruptive events (CRWMS M and O 2000a). This purpose is documented in the development plan (DP) ''Coordinate Modeling of Dike Propagation Near Drifts Consequences for TSPA-SR/LA'' (CRWMS M and O 2000b). Evaluation of that Development Plan and the work to be conducted to prepare Interim Change Notice (ICN) 1 of this report, which now includes the design option of ''Open'' drifts, indicated that no revision to that DP was needed. These analyses are intended to provide reasonable bounds for a number of expected effects: (1) Temperature changes to the waste package from exposure to magma; (2) The gas flow available to degrade waste containers during the intrusion; (3) Movement of the waste package as it is displaced by the gas, pyroclasts and magma from the intruding dike (the number of packages damaged); (4) Movement of the backfill (Backfill is treated here as a design option); (5) The nature of the mechanics of the dike/drift interaction. These analyses serve two objectives: to provide preliminary analyses needed to support evaluation of the consequences of an intrusive event and to provide a basis for addressing some of the concerns of the Nuclear Regulatory Commission (NRC) expressed in the Igneous Activity Issue Resolution Status Report

  9. Ground Control for Non-Emplacement Drifts for LA

    International Nuclear Information System (INIS)

    Tang, D.

    2004-01-01

    The purpose of this calculation is to analyze the stability of repository non-emplacement drifts during the preclosure period, and to provide a final ground support method for non-emplacement drifts for the License Application (LA). This calculation will provide input for the development of LA documents. The scope of this calculation is limited to the non-emplacement drifts including access mains, ramps, exhaust mains, turnouts, intersections between access mains and turnouts, and intersections between exhaust mains and emplacement drifts, portals, TBM launch chambers, observation drift and test alcove in the performance confirmation (PC) facilities, etc. The calculation is limited to the non-emplacement drifts subjected to a combined loading of in-situ stress, seismic stress, and/or thermal stress. Other effects such as hydrological and chemical effects are not considered in this analysis

  10. Optimality and stability of intentional and unintentional actions: I. Origins of drifts in performance.

    Science.gov (United States)

    Parsa, Behnoosh; Terekhov, Alexander; Zatsiorsky, Vladimir M; Latash, Mark L

    2017-02-01

    We address the nature of unintentional changes in performance in two papers. This first paper tested a hypothesis that unintentional changes in performance variables during continuous tasks without visual feedback are due to two processes. First, there is a drift of the referent coordinate for the salient performance variable toward the actual coordinate of the effector. Second, there is a drift toward minimum of a cost function. We tested this hypothesis in four-finger isometric pressing tasks that required the accurate production of a combination of total moment and total force with natural and modified finger involvement. Subjects performed accurate force-moment production tasks under visual feedback, and then visual feedback was removed for some or all of the salient variables. Analytical inverse optimization was used to compute a cost function. Without visual feedback, both force and moment drifted slowly toward lower absolute magnitudes. Over 15 s, the force drop could reach 20% of its initial magnitude while moment drop could reach 30% of its initial magnitude. Individual finger forces could show drifts toward both higher and lower forces. The cost function estimated using the analytical inverse optimization reduced its value as a consequence of the drift. We interpret the results within the framework of hierarchical control with referent spatial coordinates for salient variables at each level of the hierarchy combined with synergic control of salient variables. The force drift is discussed as a natural relaxation process toward states with lower potential energy in the physical (physiological) system involved in the task.

  11. Solar Drift-Pair Bursts

    Science.gov (United States)

    Stanislavsky, A.; Volvach, Ya.; Konovalenko, A.; Koval, A.

    2017-08-01

    In this paper a new sight on the study of solar bursts historically called drift pairs (DPs) is presented. Having a simple morphology on dynamic spectra of radio records (two short components separated in time, and often they are very similar) and discovered at the dawn of radio astronomy, their features remain unexplained totally up to now. Generally, the DPs are observed during the solar storms of type III bursts, but not every storm of type III bursts is linked with DPs. Detected by ground-based instruments at decameter and meter wavelengths, the DP bursts are limited in frequency bandwidth. They can drift from high frequencies to low ones and vice versa. Their frequency drift rate may be both lower and higher than typical rates of type III bursts at the same frequency range. The development of low-frequency radio telescopes and data processing provide additional possibilities in the research. In this context the fresh analysis of DPs, made from recent observations in the summer campaign of 2015, are just considered. Their study was implemented by updated tools of the UTR-2 radio telescope at 9-33 MHz. During 10-12 July of 2015, DPs forming the longest patterns on dynamic spectra are about 7% of the total number of recorded DPs. Their marvelous resemblance in frequency drift rates with the solar S-bursts is discussed.

  12. Strong drifts effects on neoclassical transport

    International Nuclear Information System (INIS)

    Tessarotto, M.; Gregoratto, D.; White, R.B.

    1996-01-01

    It is well known that strong drifts play an important role in plasma equilibrium, stability and confinement A significant example concerns, in particular for tokamak plasmas, the case of strong toroidal differential rotation produced by E x B drift which is currently regarded as potentially important for its influence in equilibrium, stability and transport. In fact, theoretically, it has been found that shear flow can substantially affect the stability of microinstabilities as well modify substantially transport. Recent experimental observations of enhanced confinement and transport regimes in Tokamaks, show, however, evidence of the existence of strong drifts in the plasma core. These are produced not only by the radial electric field [which gives rise to the E x B drift], but also by density [N s ], temperature [T s ] and mass flow [V = ωRe var-phi , with e var-phi the toroidal unit vector, R the distance for the symmetry axis of the torus and ω being the toroidal angular rotation velocity] profiles which are suitably steep. This implies that, in a significant part of the plasma core, the relevant scale lengths of the gradients [of N s , T s , ω], i.e., respectively L N , L T and L ω can be as large as the radial scale length characterizing the banana orbits, L b . Interestingly enough, the transport estimates obtained appear close or even lower than the predictions based on the simplest neoclassical model. However, as is well known, the latter applies, in a strict sense only in the case of weak drifts and also ignoring even the contribution of shear flow related to strong E x B drift. Thus a fundamental problem appears the extension of neoclassical transport theory to include the effect of strong drifts in Tokamak confinement systems. The goal of this investigation is to develop a general formulation of neoclassical transport embodying such important feature

  13. Optical drift effects in general relativity

    Science.gov (United States)

    Korzyński, Mikołaj; Kopiński, Jarosław

    2018-03-01

    We consider the question of determining the optical drift effects in general relativity, i.e. the rate of change of the apparent position, redshift, Jacobi matrix, angular distance and luminosity distance of a distant object as registered by an observer in an arbitrary spacetime. We present a fully relativistic and covariant approach, in which the problem is reduced to a hierarchy of ODE's solved along the line of sight. The 4-velocities and 4-accelerations of the observer and the emitter and the geometry of the spacetime along the line of sight constitute the input data. We build on the standard relativistic geometric optics formalism and extend it to include the time derivatives of the observables. In the process we obtain two general, non-perturbative relations: the first one between the gravitational lensing, represented by the Jacobi matrix, and the apparent position drift, also called the cosmic parallax, and the second one between the apparent position drift and the redshift drift. The applications of the results include the theoretical study of the drift effects of cosmological origin (so-called real-time cosmology) in numerical or exact Universe models.

  14. Effects of Fault Displacement on Emplacement Drifts

    International Nuclear Information System (INIS)

    Duan, F.

    2000-01-01

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10 -5 adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M and O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure

  15. Pixelated CdZnTe drift detectors

    DEFF Research Database (Denmark)

    Kuvvetli, Irfan; Budtz-Jørgensen, Carl

    2005-01-01

    A technique, the so-called Drift Strip Method (DSM), for improving the CdZnTe detector energy response to hard X-rays and gamma-rays was applied as a pixel geometry. First tests have confirmed that this detector type provides excellent energy resolution and imaging performance. We specifically...... report on the performance of 3 mm thick prototype CZT drift pixel detectors fabricated using material from eV-products. We discuss issues associated with detector module performance. Characterization results obtained from several prototype drift pixel detectors are presented. Results of position...

  16. Drift-Scale THC Seepage Model

    Energy Technology Data Exchange (ETDEWEB)

    C.R. Bryan

    2005-02-17

    The purpose of this report (REV04) is to document the thermal-hydrologic-chemical (THC) seepage model, which simulates the composition of waters that could potentially seep into emplacement drifts, and the composition of the gas phase. The THC seepage model is processed and abstracted for use in the total system performance assessment (TSPA) for the license application (LA). This report has been developed in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2005 [DIRS 172761]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this report. The plan for validation of the models documented in this report is given in Section 2.2.2, ''Model Validation for the DS THC Seepage Model,'' of the TWP. The TWP (Section 3.2.2) identifies Acceptance Criteria 1 to 4 for ''Quantity and Chemistry of Water Contacting Engineered Barriers and Waste Forms'' (NRC 2003 [DIRS 163274]) as being applicable to this report; however, in variance to the TWP, Acceptance Criterion 5 has also been determined to be applicable, and is addressed, along with the other Acceptance Criteria, in Section 4.2 of this report. Also, three FEPS not listed in the TWP (2.2.10.01.0A, 2.2.10.06.0A, and 2.2.11.02.0A) are partially addressed in this report, and have been added to the list of excluded FEPS in Table 6.1-2. This report has been developed in accordance with LP-SIII.10Q-BSC, ''Models''. This report documents the THC seepage model and a derivative used for validation, the Drift Scale Test (DST) THC submodel. The THC seepage model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral

  17. Energy drift in reversible time integration

    International Nuclear Information System (INIS)

    McLachlan, R I; Perlmutter, M

    2004-01-01

    Energy drift is commonly observed in reversible integrations of systems of molecular dynamics. We show that this drift can be modelled as a diffusion and that the typical energy error after time T is O(√T). (letter to the editor)

  18. Electromagnetic drift waves dispersion for arbitrarily collisional plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wonjae, E-mail: wol023@ucsd.edu; Krasheninnikov, Sergei I., E-mail: skrash@mae.ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); Angus, J. R. [Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375 (United States)

    2015-07-15

    The impacts of the electromagnetic effects on resistive and collisionless drift waves are studied. A local linear analysis on an electromagnetic drift-kinetic equation with Bhatnagar-Gross-Krook-like collision operator demonstrates that the model is valid for describing linear growth rates of drift wave instabilities in a wide range of plasma parameters showing convergence to reference models for limiting cases. The wave-particle interactions drive collisionless drift-Alfvén wave instability in low collisionality and high beta plasma regime. The Landau resonance effects not only excite collisionless drift wave modes but also suppress high frequency electron inertia modes observed from an electromagnetic fluid model in collisionless and low beta regime. Considering ion temperature effects, it is found that the impact of finite Larmor radius effects significantly reduces the growth rate of the drift-Alfvén wave instability with synergistic effects of high beta stabilization and Landau resonance.

  19. A preliminary comparison of F region plasma drifts and E region irregularity drifts in the auroral zone

    International Nuclear Information System (INIS)

    Ecklund, W.L.; Balsley, B.B.; Carter, D.A.

    1977-01-01

    During several days in April--May 1976 the Chatanika, Alaska, incoherent scatter radar and a temporary Doppler auroral radar located at Aniak, Alaska, were directed toward ionospheric volumes along a common magnetic field line in order to compare E region and F region drifts and associated electric fields. The Chatanika radar measured F region plasma drifts via the incoherent scatter technique, while the Aniak radar measured the drifts of E region irregularities (i.e., the radar aurora). The radar geometry was arranged so that both radars measured approximately the same velocity component of a magnetically westward or eastward motion. Preliminary data show good agreement between the drift velocity components measured by the two techniques during most of the experimental period. This result indicates that relatively modest auroral radar systems may be used, with some qualifications, to determine auroral electric fields

  20. Wireless, Ultra-Low-Power Implantable Sensor for Chronic Bladder Pressure Monitoring.

    Science.gov (United States)

    Majerus, Steve J A; Garverick, Steven L; Suster, Michael A; Fletter, Paul C; Damaser, Margot S

    2012-06-01

    The wireless implantable/intracavity micromanometer (WIMM) system was designed to fulfill the unmet need for a chronic bladder pressure sensing device in urological fields such as urodynamics for diagnosis and neuromodulation for bladder control. Neuromodulation in particular would benefit from a wireless bladder pressure sensor which could provide real-time pressure feedback to an implanted stimulator, resulting in greater bladder capacity while using less power. The WIMM uses custom integrated circuitry, a MEMS transducer, and a wireless antenna to transmit pressure telemetry at a rate of 10 Hz. Aggressive power management techniques yield an average current draw of 9 μ A from a 3.6-Volt micro-battery, which minimizes the implant size. Automatic pressure offset cancellation circuits maximize the sensing dynamic range to account for drifting pressure offset due to environmental factors, and a custom telemetry protocol allows transmission with minimum overhead. Wireless operation of the WIMM has demonstrated that the external receiver can receive the telemetry packets, and the low power consumption allows for at least 24 hours of operation with a 4-hour wireless recharge session.

  1. A Novel Scheme and Evaluations on a Long-Term and Continuous Biosensor Platform Integrated with a Dental Implant Fixture and Its Prosthetic Abutment.

    Science.gov (United States)

    Li, Yu-Jung; Lu, Chih-Cheng

    2015-09-25

    A miniature intra-oral dental implant system including a built-in biosensor device is proposed in this article. The dental implant system, or platform, is replaced over maxilla and allows relatively non-invasive procedures for a novel biosensing scheme for human blood analysis. Due to placement of the implant fixture, periodontal ligaments and the pulp structure, which are regarded as the main origin of pain, are thus removed, and long-term, continuous blood analysis and management through maxillary bone marrow becomes achievable through the dental implant platform. The new pathway of biological sensing is for the first time presented to realize an accurate and painless approach without injections. The dental implant system mainly consists of an implant fixture and a prosthetic abutment, a biosensor module, a bluetooth 4.0 wireless module and a dc button cell battery. The electrochemical biosensor possesses three electrodes, including working, reference and counter ones, which are arranged to pass through the titanium implant fixture below the biosensor module. The electrodes are exposed to the blood pool inside the maxillary bone marrow and perform oxidation/reduction reactions with the coating of biosensing enzyme. To prove the proposed platform, the immobilization process of glucose oxidase (GOD) enzyme and in vitro detections of glucose levels are successfully carried out, and proven sensitivity, linearity and repeatability of the glucose biosensor system are obtained. Moreover, a preliminary canine animal model adopting the new pathway shows significant consistency with the traditional method through dermal pricks for blood sugar detection. Despite the prospective results, further challenges in engineering implementation and clinical practices are addressed and discussed. In brief, the novel biosensing pathway and intra-oral biosensor platform may increasingly reveal their promising value and feasibilities in current bio-medical analysis, diagnosis, drug

  2. A Novel Scheme and Evaluations on a Long-Term and Continuous Biosensor Platform Integrated with a Dental Implant Fixture and Its Prosthetic Abutment

    Directory of Open Access Journals (Sweden)

    Yu-Jung Li

    2015-09-01

    Full Text Available A miniature intra-oral dental implant system including a built-in biosensor device is proposed in this article. The dental implant system, or platform, is replaced over maxilla and allows relatively non-invasive procedures for a novel biosensing scheme for human blood analysis. Due to placement of the implant fixture, periodontal ligaments and the pulp structure, which are regarded as the main origin of pain, are thus removed, and long-term, continuous blood analysis and management through maxillary bone marrow becomes achievable through the dental implant platform. The new pathway of biological sensing is for the first time presented to realize an accurate and painless approach without injections. The dental implant system mainly consists of an implant fixture and a prosthetic abutment, a biosensor module, a bluetooth 4.0 wireless module and a dc button cell battery. The electrochemical biosensor possesses three electrodes, including working, reference and counter ones, which are arranged to pass through the titanium implant fixture below the biosensor module. The electrodes are exposed to the blood pool inside the maxillary bone marrow and perform oxidation/reduction reactions with the coating of biosensing enzyme. To prove the proposed platform, the immobilization process of glucose oxidase (GOD enzyme and in vitro detections of glucose levels are successfully carried out, and proven sensitivity, linearity and repeatability of the glucose biosensor system are obtained. Moreover, a preliminary canine animal model adopting the new pathway shows significant consistency with the traditional method through dermal pricks for blood sugar detection. Despite the prospective results, further challenges in engineering implementation and clinical practices are addressed and discussed. In brief, the novel biosensing pathway and intra-oral biosensor platform may increasingly reveal their promising value and feasibilities in current bio-medical analysis

  3. SEEPAGE MODEL FOR PA INCLUDING DRIFT COLLAPSE

    International Nuclear Information System (INIS)

    C. Tsang

    2004-01-01

    The purpose of this report is to document the predictions and analyses performed using the seepage model for performance assessment (SMPA) for both the Topopah Spring middle nonlithophysal (Tptpmn) and lower lithophysal (Tptpll) lithostratigraphic units at Yucca Mountain, Nevada. Look-up tables of seepage flow rates into a drift (and their uncertainty) are generated by performing numerical simulations with the seepage model for many combinations of the three most important seepage-relevant parameters: the fracture permeability, the capillary-strength parameter 1/a, and the percolation flux. The percolation flux values chosen take into account flow focusing effects, which are evaluated based on a flow-focusing model. Moreover, multiple realizations of the underlying stochastic permeability field are conducted. Selected sensitivity studies are performed, including the effects of an alternative drift geometry representing a partially collapsed drift from an independent drift-degradation analysis (BSC 2004 [DIRS 166107]). The intended purpose of the seepage model is to provide results of drift-scale seepage rates under a series of parameters and scenarios in support of the Total System Performance Assessment for License Application (TSPA-LA). The SMPA is intended for the evaluation of drift-scale seepage rates under the full range of parameter values for three parameters found to be key (fracture permeability, the van Genuchten 1/a parameter, and percolation flux) and drift degradation shape scenarios in support of the TSPA-LA during the period of compliance for postclosure performance [Technical Work Plan for: Performance Assessment Unsaturated Zone (BSC 2002 [DIRS 160819], Section I-4-2-1)]. The flow-focusing model in the Topopah Spring welded (TSw) unit is intended to provide an estimate of flow focusing factors (FFFs) that (1) bridge the gap between the mountain-scale and drift-scale models, and (2) account for variability in local percolation flux due to

  4. Development of an equipment diagnostic system that evaluates sensor drift

    International Nuclear Information System (INIS)

    Kanada, Masaki; Arita, Setsuo; Tada, Nobuo; Yokota, Katsuo

    2011-01-01

    The importance of condition monitoring technology for equipment has increased with the introduction of condition-based maintenance in nuclear power plants. We are developing a diagnostic system using process signals for plant equipment, such as pumps and motors. It is important to enable the diagnostic system to distinguish sensor drift and equipment failure. We have developed a sensor drift diagnostic method that combines some highly correlative sensor signals by using the MT (Mahalanobis-Taguchi) method. Furthermore, we have developed an equipment failure diagnostic method that measures the Mahalanobis distance from the normal state of equipment by the MT method. These methods can respectively detect sensor drift and equipment failure, but there are the following problems. In the sensor drift diagnosis, there is a possibility of misjudging the sensor drift when the equipment failure occurs and the process signal changes because the behavior of the process signal is the same as that of the sensor drift. Oppositely, in the equipment failure diagnosis, there is a possibility of misjudging the equipment failure when the sensor drift occurs because the sensor drift influences the change of process signal. To solve these problems, we propose a diagnostic method combining the sensor drift diagnosis and the equipment failure diagnosis by the MT method. Firstly, the sensor drift values are estimated by the sensor drift diagnosis, and the sensor drift is removed from the process signal. It is necessary to judge the validity of the estimated sensor drift values before removing the sensor drift from the process signal. We developed a method for judging the validity of the estimated sensor drift values by using the drift distribution based on the sensor calibration data. And then, the equipment failure is diagnosed by using the process signals after removal of the sensor drifts. To verify the developed diagnostic system, several sets of simulation data based on abnormal cases

  5. Early Right Ventricular Assist Device Use in Patients Undergoing Continuous-Flow Left Ventricular Assist Device Implantation: Incidence and Risk Factors From the Interagency Registry for Mechanically Assisted Circulatory Support.

    Science.gov (United States)

    Kiernan, Michael S; Grandin, E Wilson; Brinkley, Marshall; Kapur, Navin K; Pham, Duc Thinh; Ruthazer, Robin; Rame, J Eduardo; Atluri, Pavan; Birati, Edo Y; Oliveira, Guilherme H; Pagani, Francis D; Kirklin, James K; Naftel, David; Kormos, Robert L; Teuteberg, Jeffrey J; DeNofrio, David

    2017-10-01

    To investigate preimplant risk factors associated with early right ventricular assist device (RVAD) use in patients undergoing continuous-flow left ventricular assist device (LVAD) surgery. Patients in the Interagency Registry for Mechanically Assisted Circulatory Support who underwent primary continuous-flow-LVAD surgery were examined for concurrent or subsequent RVAD implantation within 14 days of LVAD. Risk factors for RVAD implantation and the combined end point of RVAD or death within 14 days of LVAD were assessed with stepwise logistic regression. We compared survival between patients with and without RVAD using Kaplan-Meier method and Cox proportional hazards modeling. Of 9976 patients undergoing continuous-flow-LVAD implantation, 386 patients (3.9%) required an RVAD within 14 days of LVAD surgery. Preimplant characteristics associated with RVAD use included interagency registry for mechanically assisted circulatory support patient profiles 1 and 2, the need for preoperative extracorporeal membrane oxygenation or renal replacement therapy, severe preimplant tricuspid regurgitation, history of cardiac surgery, and concomitant procedures other than tricuspid valve repair at the time of LVAD. Hemodynamic determinants included elevated right atrial pressure, reduced pulmonary artery pulse pressure, and reduced stroke volume. The final model demonstrated good performance for both RVAD implant (area under the curve, 0.78) and the combined end point of RVAD or death within 14 days (area under the curve, 0.73). Compared with patients receiving an isolated LVAD, patients requiring RVAD had decreased 1- and 6-month survival: 78.1% versus 95.8% and 63.6% versus 87.9%, respectively ( P The need for RVAD implantation after LVAD is associated with indices of global illness severity, markers of end-organ dysfunction, and profiles of hemodynamic instability. © 2017 American Heart Association, Inc.

  6. Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

    Science.gov (United States)

    Kim, Y. H.; Kwon, H. J.; Cho, Y. S.

    2006-12-01

    The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful.

  7. Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.H. [PEFP, KAERI, DaeJeon (Korea, Republic of)]. E-mail: yhkim72@kaeri.re.kr; Kwon, H.J. [PEFP, KAERI, DaeJeon (Korea, Republic of); Cho, Y.S. [PEFP, KAERI, DaeJeon (Korea, Republic of)

    2006-12-21

    The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful.

  8. Drift tube with an electro-quadrupole magnet made with a conventional enamel wire for the proton engineering frontier project drift tube linac

    International Nuclear Information System (INIS)

    Kim, Y.H.; Kwon, H.J.; Cho, Y.S.

    2006-01-01

    The proton engineering frontier project (PEFP) drift tube linac (DTL) chose the new type of electro-quadrupole magnet (EQM) using an enameled wire for a drift tube. By using this kind of EQM, we could simplify the drift tube structure. We verified the structural stability and thermal stability of this drift tube structure through a computational analysis and a simple experiment. We also verified the stability of the enameled wire regarding corrosion through a long period test of about 1 year. It was concluded that the design and fabrication of the drift tube and the EQM were successful

  9. Nonlinear Gyrokinetic Theory With Polarization Drift

    International Nuclear Information System (INIS)

    Wang, L.; Hahm, T.S.

    2010-01-01

    A set of the electrostatic toroidal gyrokinetic Vlasov equation and the Poisson equation, which explicitly includes the polarization drift, is derived systematically by using Lie-transform method. The polarization drift is introduced in the gyrocenter equations of motion, and the corresponding polarization density is derived. Contrary to the wide-spread expectation, the inclusion of the polarization drift in the gyrocenter equations of motion does not affect the expression for the polarization density significantly. This is due to modification of the gyrocenter phase-space volume caused by the electrostatic potential [T. S. Hahm, Phys. Plasmas 3, 4658 (1996)].

  10. Spontaneous progression of ligature induced peri-implantitis at implants with different surface roughness: an experimental study in dogs

    DEFF Research Database (Denmark)

    Berglundh, T; Gotfredsen, K; Zitzmann, N U

    2007-01-01

    : The aim of the current experiment was to study the progression of peri-implantitis around implants with different surface roughness. MATERIAL AND METHODS: In five beagle dogs, three implants with either a sandblasted acid-etched surface (SLA) or a polished surface (P) were installed bilaterally......BACKGROUND: Peri-implantitis is associated with the presence of submarginal plaque, soft-tissue inflammation and advanced breakdown of the supporting bone. The progression of peri-implantitis following varying periods of continuing plaque accumulation has been studied in animal models. OBJECTIVE...... in the edentulous premolar regions. After 3 months on a plaque control regimen, experimental peri-implantitis was induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. After this 4-month period, ligatures were removed...

  11. Dental Implants in an Aged Population: Evaluation of Periodontal Health, Bone Loss, Implant Survival, and Quality of Life.

    Science.gov (United States)

    Becker, William; Hujoel, Philippe; Becker, Burton E; Wohrle, Peter

    2016-06-01

    To evaluate aged partially and fully edentulous patients who received dental implants and were maintained over time. Further, to determine how the partially and edentulous ageing populations (65 and above) with dental implants maintain bone levels, proper oral hygiene, and perceive benefits of dental implants. Since 1995, patients receiving dental implants have been prospectively entered into an Access-based computerized program (Triton Tacking System). Patient demographics (age, sex), bone quality, quantity, implant location, and type of surgery have been continuously entered into the database. The database was queried for patients receiving implants (first stage) between 66 and 93 years of age. Thirty-one patients were within this age group. Twenty-five patients returned to the clinic for periodontal and dental implant evaluation. The Periodontal Index was used to evaluate selected teeth in terms of probing depth, bleeding on probing, plaque accumulation, and mobility. Using NIH Image J, radiographs taken at second stage and last examination were measured for changes in interproximal bone levels. Once identified, each patient anomalously filled out an abbreviated quality of health life form. Due to small sample size, descriptive statistics were used to compare clinical findings. Fifteen males ranging from 78 to 84 (mean age 84 years) years and 16 females from 66 to 93 (mean age 83 years) (age range 66-93) were contacted by phone or mail and asked to return to our office for a re-examination. For this group, the first dental implants were placed in 1996 (n = initial two implants) and continuously recorded through 2013 (n = last seven implants). Thirty-one patients received a total of 84 implants. Two patients were edentulous, and the remaining were partially edentulous. Four implants were lost. Between implant placement and 6- to 7-year interval, 13 patients with 40 implants had a cumulative survival rate of 94.6%. Of the original group (n = 33), three

  12. Effect of Polyvinyl Siloxane Viscosity on Accuracy of Dental Implant Impressions

    Directory of Open Access Journals (Sweden)

    Ahmad Ghahremanloo

    2017-02-01

    Full Text Available Objectives: The aim of this study was to compare the accuracy of dental implant impressions obtained by a combination of different impression techniques and viscosities of polyvinyl siloxane (PVS.Materials and Methods: Four parallel fixtures were placed between mental foramina in a master model of lower dental arch. Three different viscosities (putty/light body, medium body/light body, and monophase: heavy body and direct and indirect techniques (six groups were used, and seven impressions were obtained from each group (n=42. To measure the accuracy of impressions, drift, horizontal, and vertical angles of the implants, as well as the hex rotation of the implants in casts were evaluated using a digitizer device (1μm accuracy, in comparison with master arch. Data were analyzed using five-factor two-way ANOVA and Tukey’s post-hoc test.Results: The accuracy of impressions was assessed and the results showed that direct technique was not significantly different from indirect technique (P>0.05. Also, there were no significant differences between the mentioned viscosities except for the horizontal angle (P=0.006.Conclusions: Viscosity of impression materials is of high significance for the accuracy of dental impressions.Keywords: Dental Materials; Dental Implants; Dental Impression Technique; Viscosity; Vinyl Polysiloxane; Dimensional Measurement Accuracy

  13. A new variable transformation technique for the nonlinear drift vortex

    International Nuclear Information System (INIS)

    Orito, Kohtaro

    1996-02-01

    The dipole vortex solution of the Hasegawa-Mima equation describing the nonlinear drift wave is a stable solitary wave which is called the modon. The profile of the modon depends on the nonlinearity of the ExB drift. In order to investigate the nonlinear drift wave more accurately, the effect of the polarization drift needs to be considered. In case of containing the effect of the polarization drift the profile of the electrostatic potential is distorted in the direction perpendicular to the ExB drift. (author)

  14. The OPAL vertex drift chamber

    International Nuclear Information System (INIS)

    Carter, J.R.; Elcombe, P.A.; Hill, J.C.; Roach, C.M.; Armitage, J.C.; Carnegie, R.K.; Estabrooks, P.; Hemingway, R.; Karlen, D.; McPherson, A.; Pinfold, J.; Roney, J.M.; Routenburg, P.; Waterhouse, J.; Hargrove, C.K.; Klem, D.; Oakham, F.G.; Carter, A.A.; Jones, R.W.L.; Lasota, M.M.B.; Lloyd, S.L.; Pritchard, T.W.; Wyatt, T.R.

    1990-01-01

    A high precision vertex drift chamber has been installed in the OPAL experiment at LEP. The design of the chamber and the associated readout electronics is described. The performance of the system has been studied using cosmic ray muons and the results of these studies are presented. A space resolution of 50 μm in the drift direction is obtained using the OPAL central detector gas mixture at 4 bar. (orig.)

  15. Intrafractional baseline drift during free breathing breast cancer radiation therapy.

    Science.gov (United States)

    Jensen, Christer Andre; Acosta Roa, Ana María; Lund, Jo-Åsmund; Frengen, Jomar

    2017-06-01

    Intrafraction motion in breast cancer radiation therapy (BCRT) has not yet been thoroughly described in the literature. It has been observed that baseline drift occurs as part of the intrafraction motion. This study aims to measure baseline drift and its incidence in free-breathing BCRT patients using an in-house developed laser system for tracking the position of the sternum. Baseline drift was monitored in 20 right-sided breast cancer patients receiving free breathing 3D-conformal RT by using an in-house developed laser system which measures one-dimensional distance in the AP direction. A total of 357 patient respiratory traces from treatment sessions were logged and analysed. Baseline drift was compared to patient positioning error measured from in-field portal imaging. The mean overall baseline drift at end of treatment sessions was -1.3 mm for the patient population. Relatively small baseline drift was observed during the first fraction; however it was clearly detected already at the second fraction. Over 90% of the baseline drift occurs during the first 3 min of each treatment session. The baseline drift rate for the population was -0.5 ± 0.2 mm/min in the posterior direction the first minute after localization. Only 4% of the treatment sessions had a 5 mm or larger baseline drift at 5 min, all towards the posterior direction. Mean baseline drift in the posterior direction in free breathing BCRT was observed in 18 of 20 patients over all treatment sessions. This study shows that there is a substantial baseline drift in free breathing BCRT patients. No clear baseline drift was observed during the first treatment session; however, baseline drift was markedly present at the rest of the sessions. Intrafraction motion due to baseline drift should be accounted for in margin calculations.

  16. Adaptive Online Sequential ELM for Concept Drift Tackling

    Directory of Open Access Journals (Sweden)

    Arif Budiman

    2016-01-01

    Full Text Available A machine learning method needs to adapt to over time changes in the environment. Such changes are known as concept drift. In this paper, we propose concept drift tackling method as an enhancement of Online Sequential Extreme Learning Machine (OS-ELM and Constructive Enhancement OS-ELM (CEOS-ELM by adding adaptive capability for classification and regression problem. The scheme is named as adaptive OS-ELM (AOS-ELM. It is a single classifier scheme that works well to handle real drift, virtual drift, and hybrid drift. The AOS-ELM also works well for sudden drift and recurrent context change type. The scheme is a simple unified method implemented in simple lines of code. We evaluated AOS-ELM on regression and classification problem by using concept drift public data set (SEA and STAGGER and other public data sets such as MNIST, USPS, and IDS. Experiments show that our method gives higher kappa value compared to the multiclassifier ELM ensemble. Even though AOS-ELM in practice does not need hidden nodes increase, we address some issues related to the increasing of the hidden nodes such as error condition and rank values. We propose taking the rank of the pseudoinverse matrix as an indicator parameter to detect “underfitting” condition.

  17. Characterizing the nature of subpulse drifting in pulsars

    Science.gov (United States)

    Basu, Rahul; Mitra, Dipanjan

    2018-04-01

    We report a detailed study of subpulse drifting in four long-period pulsars. These pulsars were observed in the Meterwavelength Single-pulse Polarimetric Emission Survey and the presence of phase-modulated subpulse drifting was reported in each case. We carried out longer duration and more sensitive observations lasting 7000-12 000 periods in the frequency range 306-339 MHz. The drifting features were characterized in great detail, including the phase variations across the pulse window. For two pulsars, J0820-1350 and J1720-2933, the phases changed steadily across the pulse window. The pulsar J1034-3224 has five components. The leading component was very weak and was barely detectable in our single-pulse observations. The four trailing components showed subpulse drifting. The phase variations changed in alternate components with a reversal in the sign of the gradient. This phenomenon is known as bi-drifting. The pulsar J1555-3134 showed two distinct peak frequencies of comparable strengths in the fluctuation spectrum. The two peaks did not appear to be harmonically related and were most likely a result of different physical processes. Additionally, the long observations enabled us to explore the temporal variations of the drifting features. The subpulse drifting was largely constant with time but small fluctuations around a mean value were seen.

  18. The large cylindrical drift chamber of TASSO

    International Nuclear Information System (INIS)

    Boerner, H.; Fischer, H.M.; Hartmann, H.; Loehr, B.; Wollstadt, M.; Fohrmann, R.; Schmueser, P.; Cassel, D.G.; Koetz, U.; Kowalski, H.

    1980-03-01

    We have built and operated a large cylindrical drift chamber for the TASSO experiment at the DESY storage ring, PETRA. The chamber has a length of 3.5 m, a diameter of 2.5 m, and a total of 2340 drift cells. The cells are arranged in 15 concentric layers such that tracks can be reconstructed in three dimensions. A spatial resolution of 220 μm has been achieved for tracks of normal incidence on the drift cells. (orig.)

  19. Electron drift in a large scale solid xenon

    International Nuclear Information System (INIS)

    Yoo, J.; Jaskierny, W.F.

    2015-01-01

    A study of charge drift in a large scale optically transparent solid xenon is reported. A pulsed high power xenon light source is used to liberate electrons from a photocathode. The drift speeds of the electrons are measured using a 8.7 cm long electrode in both the liquid and solid phase of xenon. In the liquid phase (163 K), the drift speed is 0.193 ± 0.003 cm/μs while the drift speed in the solid phase (157 K) is 0.397 ± 0.006 cm/μs at 900 V/cm over 8.0 cm of uniform electric fields. Therefore, it is demonstrated that a factor two faster electron drift speed in solid phase xenon compared to that in liquid in a large scale solid xenon

  20. New orthopaedic implant management tool for computer-assisted planning, navigation, and simulation: from implant CAD files to a standardized XML-based implant database.

    Science.gov (United States)

    Sagbo, S; Blochaou, F; Langlotz, F; Vangenot, C; Nolte, L-P; Zheng, G

    2005-01-01

    Computer-Assisted Orthopaedic Surgery (CAOS) has made much progress over the last 10 years. Navigation systems have been recognized as important tools that help surgeons, and various such systems have been developed. A disadvantage of these systems is that they use non-standard formalisms and techniques. As a result, there are no standard concepts for implant and tool management or data formats to store information for use in 3D planning and navigation. We addressed these limitations and developed a practical and generic solution that offers benefits for surgeons, implant manufacturers, and CAS application developers. We developed a virtual implant database containing geometrical as well as calibration information for orthopedic implants and instruments, with a focus on trauma. This database has been successfully tested for various applications in the client/server mode. The implant information is not static, however, because manufacturers periodically revise their implants, resulting in the deletion of some implants and the introduction of new ones. Tracking these continuous changes and keeping CAS systems up to date is a tedious task if done manually. This leads to additional costs for system development, and some errors are inevitably generated due to the huge amount of information that has to be processed. To ease management with respect to implant life cycle, we developed a tool to assist end-users (surgeons, hospitals, CAS system providers, and implant manufacturers) in managing their implants. Our system can be used for pre-operative planning and intra-operative navigation, and also for any surgical simulation involving orthopedic implants. Currently, this tool allows addition of new implants, modification of existing ones, deletion of obsolete implants, export of a given implant, and also creation of backups. Our implant management system has been successfully tested in the laboratory with very promising results. It makes it possible to fill the current gap

  1. New Criteria of Indication and Selection of Patients to Cochlear Implant

    Directory of Open Access Journals (Sweden)

    André L. L. Sampaio

    2011-01-01

    Full Text Available Numerous changes continue to occur in cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound unilateral hearing loss rather then the prior requirement of a bilateral profound loss. Furthermore, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low-frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. This paper will review the new concepts in the candidacy of cochlear implant. Medline data base was used to search articles dealing with the following topics: cochlear implant in younger children, cochlear implant and hearing preservation, cochlear implant for unilateral deafness and tinnitus, genetic hearing loss and cochlear implant, bilateral cochlear implant, neuropathy and cochlear implant and neural plasticity, and the selection of patients for cochlear implant.

  2. PAIN RELIEF MEDIATED BY IMPLANTABLE DRUG-DELIVERY DEVICES

    NARCIS (Netherlands)

    HOEKSTRA, A

    Various totally implantable drug delivery systems from single access ports to micropumps are now available for administration of repeated boluses, and continuous or programmable infusions. In this respect, emphasis is given to a relatively cheap, totally implantable system for self-administering

  3. Construction of a full-length prototype of the BESIII drift chamber and on-detector test for the BESIII drift chamber electronics

    International Nuclear Information System (INIS)

    Qin Zhonghua; Wu Linghui; Liu Jianbei; Chinese Academy of Sciences, Beijing; Yan Zhikang; Hunan Univ., Changsha; Chen Yuanbo; Chen Chang; Xu Meihang; Wang Lan; Ma Xiaoyan; Jin Yan; Liu Rongguang; Tang Xiao; Zhang Guifang; Zhu Qiming; Sheng Huayi; Zhu Kejun

    2007-01-01

    A full-length prototype of the BESIII drift chamber was built. The experience gained on gas sealing, high voltage supply and front-end electronics installation should be greatly beneficial to the successful construction of the BESIII drift chamber. An on-detector test of the BESIII drift chamber electronics was carried out with the constructed prototype chamber. The noise performance, drift time and charge measurements, and electronics gains were examined specifically. The final test results indicate that the electronics have a good performance and can satisfy their design requirements. (authors)

  4. Drift tubes of Linac 2

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    With the advent of the 800 MeV PS Booster in 1972, the original injector of the PS, a 50 MeV Alvarez-type proton linac, had reached its limits, in terms of intensity and stability. In 1973 one therefore decided to build a new linac (Linac 2), also with a drift-tube Alvarez structure and an energy of 50 MeV. It had a new Cockcroft-Walton preinjector with 750 keV, instead of the previous one with 500 keV. Linac 2 was put into service in 1980. The old Linac 1 was then used for the study of, and later operation with, various types of ions. This picture shows Linac 2 drift-tubes, suspended on stems coming from the top, in contrast to Linac 1, where the drift-tubes stood on stems coming from the bottom.

  5. Measurements of electron drift and diffusion properties in a large cylindrical drift chamber (TPC) with parallel electric and magnetic fields

    International Nuclear Information System (INIS)

    Richstein, J.

    1986-01-01

    This work describes measurements on the drift of electrons in gases, using the TPC90, the prototype of the ALEPH Time Projection Chamber. Tracks which were created by UV-Laser ionization have been drifted over distances of up to 1.3 m in parallel electric and magnetic fields. Electron drift properties have been systematically measured as a function of these, in several gas mixtures. (orig./HSI)

  6. Calculation of drift seepage for alternative emplacement designs

    International Nuclear Information System (INIS)

    Li, Guomin; Tsang, Chin-Fu; Birkholzer, Jens

    1999-01-01

    The calculations presented in this report are performed to obtain seepage rates into drift and boreholes for two alternative designs of drift and waste emplacement at Yucca Mountain. The two designs are defined according to the Scope of Work 14012021M1, activity 399621, drafted October 6, 1998, and further refined in a conference telephone call on October 13, 1998, between Mark Balady, Jim Blink, Rob Howard and Chin-Fu Tsang. The 2 designs considered are: (1) Design A--Horizontal boreholes 1.0 m in diameter on both sides of the drift, with each borehole 8 m long and inclined to the drift axis by 30 degrees. The pillar between boreholes, measured parallel to the drift axis, is 3.3 m. In the current calculations, a simplified model of an isolated horizontal borehole 8 m long will be simulated. The horizontal borehole will be located in a heterogeneous fracture continuum representing the repository layer. Three different realizations will be taken from the heterogeneous field, representing three different locations in the rock. Seepage for each realization is calculated as a function of the percolation flux. Design B--Vertical boreholes, 1.0 m in diameter and 8.0 m deep, drilled from the bottom of an excavated 8.0 m diameter drift. Again, the drift with the vertical borehole will be assumed to be located in a heterogeneous fracture continuum, representing the rock at the repository horizon. Two realizations are considered, and seepage is calculated for the 8-m drift with and without the vertical 1-m borehole at its bottom

  7. Continuous functionally graded porous titanium scaffolds manufactured by selective laser melting for bone implants.

    Science.gov (United States)

    Han, Changjun; Li, Yan; Wang, Qian; Wen, Shifeng; Wei, Qingsong; Yan, Chunze; Hao, Liang; Liu, Jie; Shi, Yusheng

    2018-04-01

    A significant requirement for a bone implant is to replicate the functional gradient across the bone to mimic the localization change in stiffness. In this work, continuous functionally graded porous scaffolds (FGPSs) based on the Schwartz diamond unit cell with a wide range of graded volume fraction were manufactured by selective laser melting (SLM). The micro-topology, strut dimension characterization and effect of graded volume fraction on the mechanical properties of SLM-processed FGPSs were systematically investigated. The micro-topology observations indicate that diamond FGPSs with a wide range of graded volume fraction from 7.97% to 19.99% were fabricated without any defects, showing a good geometric reproduction of the original designs. The dimensional characterization demonstrates the capability of SLM in manufacturing titanium diamond FGPSs with the strut size of 483-905µm. The elastic modulus and yield strength of the titanium diamond FGPSs can be tailored in the range of 0.28-0.59GPa and 3.79-17.75MPa respectively by adjusting the graded volume fraction, which are comparable to those of the cancellous bone. The mathematical relationship between the graded porosity and compression properties of a FGPS was revealed. Furthermore, two equations based on the Gibson and Ashby model have been established to predict the modulus and yield strength of SLM-processed diamond FGPSs. Compared to homogeneous diamond porous scaffolds, FGPSs provide a wide range of mutative pore size and porosity, which are potential to be tailored to optimize the pore space for bone tissue growth. The findings provide a basis of new methodologies to design and manufacture superior graded scaffolds for bone implant applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. New iGrav superconducting gravimeter: accuracy, drift and first results

    Science.gov (United States)

    Le Moigne, N.; Champollion, C.; Warburton, R. J.; Bayer, R.; Deville, S.; Doerflinger, E.; chery, J.; Vernant, P.; Boudin, F.; Collard, P.

    2011-12-01

    A GWR iGrav superconducting gravimeter has been installed in the Larzac karstic area (Southern France near the Mediterranean Sea, elevation 800m, karst thickness 200m). Continuous sub-μGal gravity measurements are needed to study water storage and transfer in the non-saturated zone of the karstic area. The GWR iGrav is a new generation of superconducting gravimeter of reduced size (Dewar 15L) with simplified installation. At first, the specifications of the iGrav site will be presented, then the drift behaviour and the data processing. The drift quickly decreases to less than 0.1 μGal per day and only a few offsets are observed in the data. In order to look at the stability of the iGrav over a wide time period, a FG5 gravimeter is used for bi-monthly absolute gravity measurements and for frequent calibrations. As a result of the installation, the iGrav allows sub-μGal gravity monitoring only a few weeks after the beginning of the installation. After having discussed the instrumental and data processing points of view, preliminary results on the local karstic water storage will be presented and interpreted by combining different geophysical data. Continuous gravity data allow to study processes at different timescale such as summer evapotranspiration or high precipitating event characteristic of the Mediterranean autumn.

  9. Modelling of the space-to-drift-time relationship of the ATLAS monitored drift-tube chambers in the presence of magnetic fields

    International Nuclear Information System (INIS)

    Dubbert, J.; Horvat, S.; Khartchenko, D.; Kortner, O.; Kotov, S.; Kroha, H.; Manz, A.; Nikolaev, K.; Rauscher, F.; Richter, R.; Staude, A.; Valderanis, Ch.

    2007-01-01

    The ATLAS muon spectrometer uses tracking chambers consisting of up to 5m long drift tubes filled with Ar:CO 2 (93:7) at 3bar. The chambers are run in a average toroidal magnetic field of 0.4T created by 8 air core coils. They provide a track-point accuracy of 40μm if the space-to-drift-time relationship r(t) is known with 20μm accuracy. The magnetic field B influences the electron drift inside the tubes: the maximum drift time t max =700ns increases by ∼70ns/T 2 B 2 . B varies by up to +/-0.4T along the tubes of the chambers mounted near the magnet coils which translates into a variation of t max of up to 45ns. The dependence of r(t) on B must be taken into account. Test-beam measurements show that the electron drift in case of B 0 can be modelled with the required accuracy by a Langevin equation with a friction term which is slightly non-linear in the drift velocity

  10. Indoor spray measurement of spray drift potential using a spray drift test bench : effect of drift-reducing nozzle types, spray boom height, nozzle spacing and forward speed

    NARCIS (Netherlands)

    Moreno Ruiz, J.R.

    2014-01-01

    In a series of indoor experiments spray drift potential was assessed when spraying over a spray drift testbench with two different driving speeds, 2m/s and 4m/s, two different spray boom heights, 30 cm and 50 cm, and two different nozzle spacing, 25 cm and 50 cm, for six different nozzle types. The

  11. A single pre-operative antibiotic dose is as effective as continued antibiotic prophylaxis in implant-based breast reconstruction: A matched cohort study.

    Science.gov (United States)

    Townley, William A; Baluch, Narges; Bagher, Shaghayegh; Maass, Saskia W M C; O'Neill, Anne; Zhong, Toni; Hofer, Stefan O P

    2015-05-01

    Infections following implant-based breast reconstruction can lead to devastating consequences. There is currently no consensus on the need for post-operative antibiotics in preventing immediate infection. This study compared two different methods of infection prevention in this group of patients. A retrospective matched cohort study was performed on consecutive women undergoing implant-based breast reconstruction at University Health Network, Toronto (November 2008-December 2012). All patients received a single pre-operative intravenous antibiotic dose. Group A received minimal interventions and Group B underwent maximal prophylactic measures. Patient (age, smoking, diabetes, co-morbidities), oncologic and procedural variables (timing and laterality) were collected. Univariate and multivariate logistic regression were performed to compare outcomes between the two groups. Two hundred and eight patients underwent 647 implant procedures. After matching the two treatment groups by BMI, 94 patients in each treatment group yielding a total of 605 implant procedures were selected for analysis. The two groups were comparable in terms of patient and disease variables. Post-operative wound infection was similar in Group A (n = 11, 12%) compared with Group B (n = 9, 10%; p = 0.8). Univariate analysis revealed only pre-operative radiotherapy to be associated with the development of infection (0.004). Controlling for the effect of radiotherapy, multivariate analysis demonstrated that there was no statistically significant difference between the two methods for infection prevention. Our findings suggest that a single pre-operative dose of intravenous antibiotics is equally as effective as continued antibiotic prophylaxis in preventing immediate infection in patients undergoing implant-based breast reconstructions. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Low Drift Type N Thermocouples for Nuclear Applications

    International Nuclear Information System (INIS)

    Scervini, M.; Rae, C.

    2013-06-01

    Thermocouples are the most commonly used sensors for temperature measurement in nuclear reactors. They are crucial for the control of current nuclear reactors and for the development of GEN IV reactors. In nuclear applications thermocouples are strongly affected by intense neutron fluxes. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time dependent change in composition and, as a consequence, a time dependent drift of the thermocouple signal. Thermocouple drift can be very significant for in-pile temperature measurements and may render the temperature sensors unreliable after exposure to nuclear radiation for relatively short times compared to the life required for temperature sensors in nuclear applications. Previous experiences with type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly type N thermocouples are expected to be only slightly affected by neutron fluxes. Currently the use of Nickel based thermocouples is limited to temperatures lower than 1000 deg. C due to drift related to phenomena other than nuclear irradiation. In this work, undertaken as part of the European project METROFISSION, the drift of type N thermocouples has been investigated in the temperature range 600-1300 deg. C. The approach of this study is based on the attempt to separate the contributions of each thermo-element to drift. In order to identify the dominant thermo-element for drift, the contributions of both positive (NP) and negative (NN) thermo-elements to the total drift of 3.2 mm diameter MIMS thermocouples have been measured in each drift test using a pure Pt thermo-element as a reference. Conventional Inconel-600 sheathed type N thermocouples have been compared with type N thermocouples sheathed in a new alloy. At temperatures higher than 1000 deg. C conventional Inconel600 sheathed type N thermocouples can experience a

  13. Chitosan-Recombinamer Layer-by-Layer Coatings for Multifunctional Implants

    Directory of Open Access Journals (Sweden)

    Jeevan Prasaad Govindharajulu

    2017-02-01

    Full Text Available The main clinical problems for dental implants are (1 formation of biofilm around the implant—a condition known as peri-implantitis and (2 inadequate bone formation around the implant—lack of osseointegration. Therefore, developing an implant to overcome these problems is of significant interest to the dental community. Chitosan has been reported to have good biocompatibility and anti-bacterial activity. An osseo-inductive recombinant elastin-like biopolymer (P-HAP, that contains a peptide derived from the protein statherin, has been reported to induce biomineralization and osteoblast differentiation. In this study, chitosan/P-HAP bi-layers were built on a titanium surface using a layer-by-layer (LbL assembly technique. The difference in the water contact angle between consecutive layers, the representative peaks in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS, X-ray photoelectron spectroscopy (XPS, and the changes in the topography between surfaces with a different number of bi-layers observed using atomic force microscopy (AFM, all indicated the successful establishment of chitosan/P-HAP LbL assembly on the titanium surface. The LbL-modified surfaces showed increased biomineralization, an appropriate mouse pre-osteoblastic cell response, and significant anti-bacterial activity against Streptococcus gordonii, a primary colonizer of tissues in the oral environment

  14. Predicting public sector accountability : From agency drift to forum drift

    NARCIS (Netherlands)

    Schillemans, Thomas|info:eu-repo/dai/nl/229913881; Busuioc, Madalina

    2015-01-01

    Principal-agent theory has been the dominant theory at the heart of public sector accountability research. The notion of the potentially drifting agent-such as independent public agencies, opaque transnational institutions, or recalcitrant street-level bureaucrats-has been the guiding paradigm in

  15. On nonlinear periodic drift waves

    International Nuclear Information System (INIS)

    Kauschke, U.; Schlueter, H.

    1990-09-01

    Nonlinear periodic drift waves are investigated on the basis of a simple perturbation scheme for both the amplitude and inverse frequency. The coefficients for the generation of the forced harmonics are derived, a nonlinear dispersion relation is suggested and a criterion for the onset of the modulational instability is obtained. The results are compared with the ones obtained with the help of a standard KBM-treatment. Moreover cnoidal drift waves are suggested and compared to an experimental observation. (orig.)

  16. Long-drift calorimeter modules for the Soudan 2 nucleon decay detector

    International Nuclear Information System (INIS)

    Hoftiezer, J.

    1985-01-01

    The first full size 5-ton detector modules for the Soudan 2 nucleon decay experiment have been assembled and operated. Modules consist of a hexagonal array of drift tubes and corrugated steel, instrumented to read out three-dimensional track positions and pulse height. These will be assembled to form an isotropic, continuously sensitive, self-triggering detector. Details of the design, construction, operation and performance of the modules are discussed. 7 refs., 10 figs

  17. Variable-energy drift-tube linear accelerator

    Science.gov (United States)

    Swenson, Donald A.; Boyd, Jr., Thomas J.; Potter, James M.; Stovall, James E.

    1984-01-01

    A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.

  18. Field experiment on spray drift: deposition and airborne drift during application to a winter wheat crop.

    Science.gov (United States)

    Wolters, André; Linnemann, Volker; van de Zande, Jan C; Vereecken, Harry

    2008-11-01

    A field experiment was performed to evaluate various techniques for measuring spray deposition and airborne drift during spray application to a winter wheat crop. The application of a spraying agent containing the fluorescent dye Brilliant Sulfo Flavine by a conventional boom sprayer was done according to good agricultural practice. Deposition was measured by horizontal collectors in various arrangements in and outside the treated area. Airborne spray drift was measured both with a passive and an active air collecting system. Spray deposits on top of the treated canopy ranged between 68 and 71% of the applied dose and showed only small differences for various arrangements of the collectors. Furthermore, only small variations were measured within the various groups of collectors used for these arrangements. Generally, the highest spray deposition outside the treated area was measured close to the sprayed plot and was accompanied by a high variability of values, while a rapid decline of deposits was detected in more remote areas. Estimations of spray deposits with the IMAG Drift Calculator were in accordance with experimental findings only for areas located at a distance of 0.5-4.5 m from the last nozzle, while there was an overestimation of a factor of 4 at a distance of 2.0-3.0 m, thus revealing a high level of uncertainty of the estimation of deposition for short distances. Airborne spray drift measured by passive and active air collecting systems was approximately at the same level, when taking into consideration the collector efficiency of the woven nylon wire used as sampling material for the passive collecting system. The maximum value of total airborne spray drift for both spray applications (0.79% of the applied dose) was determined by the active collecting system. However, the comparatively high variability of measurements at various heights above the soil by active and passive collecting systems revealed need for further studies to elucidate the spatial

  19. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  20. Zonal Flows Driven by Small-Scale Drift-Alfven Modes

    International Nuclear Information System (INIS)

    Li Dehui; Zhou Deng

    2011-01-01

    Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary modes propagating at both electron and ion diamagnetic drift directions in contrast to the assertion in previous studies that only primary modes propagating in the ion diamagnetic drift directions can drive zonal instabilities. Generally, the growth rate of the driven zonal mode is in the same order as that in previous study. However, different from the previous work, the growth rate is no longer proportional to the difference between the diamagnetic drift frequencies of electrons and ions. (magnetically confined plasma)

  1. 21 CFR 874.3695 - Mandibular implant facial prosthesis.

    Science.gov (United States)

    2010-04-01

    ... made of materials such as stainless steel, tantalum, titanium, cobalt-chromium based alloy... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mandibular implant facial prosthesis. 874.3695... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3695 Mandibular implant...

  2. Effect of Polyvinyl Siloxane Viscosity on Accuracy of Dental Implant Impressions.

    Science.gov (United States)

    Ghahremanloo, Ahmad; Seifi, Mahdieh; Ghanbarzade, Jalil; Abrisham, Seyyed Mohammad; Javan, Rashid Abdolah

    2017-01-01

    The aim of this study was to compare the accuracy of dental implant impressions obtained by a combination of different impression techniques and viscosities of polyvinyl siloxane (PVS). Four parallel fixtures were placed between mental foramina in a master model of lower dental arch. Three different viscosities (putty/light body, medium body/light body, and monophase: heavy body) and direct and indirect techniques (six groups) were used, and seven impressions were obtained from each group (n=42). To measure the accuracy of impressions, drift, horizontal, and vertical angles of the implants, as well as the hex rotation of the implants in casts were evaluated using a digitizer device (1μm accuracy), in comparison with master arch. Data were analyzed using five-factor two-way ANOVA and Tukey's post-hoc test. The accuracy of impressions was assessed and the results showed that direct technique was not significantly different from indirect technique (P>0.05). Also, there were no significant differences between the mentioned viscosities except for the horizontal angle (P=0.006). Viscosity of impression materials is of high significance for the accuracy of dental impressions.

  3. The Geodiversity in Drift Sand Landscapes of The Netherlands

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk; Riksen, Michel

    2015-04-01

    The authors carried out detailed field studies of more than twelve drift sand landscapes in The Netherlands. The objective of these studies was to restore Natura-2000 values by restoring the wind activity. Active drift sands occur almost exclusively in The Netherlands, Natura 2000 habitat 2330 'Inland dunes with open Corynephorus and Agrostis grasslands', for which reason our country is largely responsible for this European landscape. Active drift sands had almost disappeared for two reasons: first, the stabilization of the drift sands by air pollution, mainly nitrogen, which stimulates the growth of algae and grasses that initiate soil formation, and second, by the growth of forests surrounding the sands, which decreases the wind force. The restoration studies revealed differences in the geodiversity between and within the drift sand areas. Whereas the drift sands on geological and soil maps show as almost homogenous areas, they have in fact highly variable geo-conditions of which examples will be given. These geodiversity aspects concern differences in geomorphological structure, origin, sediments and age of the drift sands. Differences in wind and water erosion, trampling and soil formation add to the geodiversity within the drift sand areas. Especially in the primary stages of succession the differences in geodiversity are relevant for the Natura-2000 values. We discerned three main types of active sands. Firstly, the impressive drift sands with large parabolic dune structures, often consisting of series of interlocking parabolic dunes. They developed from the northeast towards the southwest, against the direction of the dominant wind, and must have taken centuries to develop. Small parts of these systems are still active, other parts show different degrees of soil formation. Their origin is still unclear but probably dates from medieval times (Heidinga, 1985, Jungerius & Riksen, 2008). Second are the drift sand areas with irregular hills from 0.5 to about 2

  4. Mechanical properties of ion-implanted alumina

    International Nuclear Information System (INIS)

    Pope, S.G.

    1988-01-01

    Monolithic oxide ceramics are being proposed as structural materials in continuously more-demanding applications. The demands being placed on these materials have caused concern pertaining to the continued growth of oxide structural ceramics due to limited toughness. The realization that ceramic strength and toughness can be affected by surface conditions has led to many surface-modification techniques, all striving to improve the mechanical properties of ceramics. Along these lines, the effects of ion implantation as a surface modification technique for improvement of the mechanical properties of alumina were studied. Initially, sapphire samples were implanted with elemental ion species that would produce oxide precipitates within the sapphire surface when annealed in an oxygen-containing atmosphere. Optimum conditions as determined from implantation into sapphire were then used to modify a polycrystalline alumina. Specific modifications in microhardness, indentation fracture toughness and flexure strength are reported for the parameters studied. Microstructure and phase relationships related to modified surfaces properties are also reported

  5. The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account.

    Science.gov (United States)

    Cohen Hoffing, Russell; Karvelis, Povilas; Rupprechter, Samuel; Seriès, Peggy; Seitz, Aaron R

    2018-01-01

    Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM) to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB) to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB), rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch). While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT) switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.

  6. DRIFT-SCALE COUPLED PROCESSES (DST AND TH SEEPAGE) MODELS

    International Nuclear Information System (INIS)

    J.T. Birkholzer; S. Mukhopadhyay

    2005-01-01

    The purpose of this report is to document drift-scale modeling work performed to evaluate the thermal-hydrological (TH) behavior in Yucca Mountain fractured rock close to waste emplacement drifts. The heat generated by the decay of radioactive waste results in rock temperatures elevated from ambient for thousands of years after emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, giving rise to water redistribution and altered flow paths. The predictive simulations described in this report are intended to investigate fluid flow in the vicinity of an emplacement drift for a range of thermal loads. Understanding the TH coupled processes is important for the performance of the repository because the thermally driven water saturation changes affect the potential seepage of water into waste emplacement drifts. Seepage of water is important because if enough water gets into the emplacement drifts and comes into contact with any exposed radionuclides, it may then be possible for the radionuclides to be transported out of the drifts and to the groundwater below the drifts. For above-boiling rock temperatures, vaporization of percolating water in the fractured rock overlying the repository can provide an important barrier capability that greatly reduces (and possibly eliminates) the potential of water seeping into the emplacement drifts. In addition to this thermal process, water is inhibited from entering the drift opening by capillary forces, which occur under both ambient and thermal conditions (capillary barrier). The combined barrier capability of vaporization processes and capillary forces in the near-field rock during the thermal period of the repository is analyzed and discussed in this report

  7. Noise-induced drift in two-dimensional anisotropic systems

    Science.gov (United States)

    Farago, Oded

    2017-10-01

    We study the isothermal Brownian dynamics of a particle in a system with spatially varying diffusivity. Due to the heterogeneity of the system, the particle's mean displacement does not vanish even if it does not experience any physical force. This phenomenon has been termed "noise-induced drift," and has been extensively studied for one-dimensional systems. Here, we examine the noise-induced drift in a two-dimensional anisotropic system, characterized by a symmetric diffusion tensor with unequal diagonal elements. A general expression for the mean displacement vector is derived and presented as a sum of two vectors, depicting two distinct drifting effects. The first vector describes the tendency of the particle to drift toward the high diffusivity side in each orthogonal principal diffusion direction. This is a generalization of the well-known expression for the noise-induced drift in one-dimensional systems. The second vector represents a novel drifting effect, not found in one-dimensional systems, originating from the spatial rotation in the directions of the principal axes. The validity of the derived expressions is verified by using Langevin dynamics simulations. As a specific example, we consider the relative diffusion of two transmembrane proteins, and demonstrate that the average distance between them increases at a surprisingly fast rate of several tens of micrometers per second.

  8. Ultra-low mass drift chambers

    Science.gov (United States)

    Assiro, R.; Cappelli, L.; Cascella, M.; De Lorenzis, L.; Grancagnolo, F.; Ignatov, F.; L'Erario, A.; Maffezzoli, A.; Miccoli, A.; Onorato, G.; Perillo, M.; Piacentino, G.; Rella, S.; Rossetti, F.; Spedicato, M.; Tassielli, G.; Zavarise, G.

    2013-08-01

    We present a novel low mass drift chamber concept, developed in order to fulfill the stringent requirements imposed by the experiments for extremely rare processes, which require high resolutions (order of 100-200 keV/c) for particle momenta in a range (50-100 MeV/c) totally dominated by the multiple scattering contribution. We describe a geometry optimization procedure and a new wiring strategy with a feed-through-less wire anchoring system developed and tested on a drift chamber prototype under completion at INFN-Lecce .

  9. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Science.gov (United States)

    2010-04-01

    ... implant). 872.3970 Section 872.3970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3970 Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis...

  10. Silicon drift detectors with on-chip electronics for x-ray spectroscopy.

    Science.gov (United States)

    Fiorini, C; Longoni, A; Hartmann, R; Lechner, P; Strüder, L

    1997-01-01

    The silicon drift detector (SDD) is a semiconductor device based on high resistivity silicon fully depleted through junctions implanted on both sides of the semiconductor wafer. The electrons generated by the ionizing radiation are driven by means of a suitable electric field from the point of interaction toward a collecting anode of small capacitance, independent of the active area of the detector. A suitably designed front-end JFET has been directly integrated on the detector chip close to the anode region, in order to obtain a nearly ideal capacitive matching between detector and transistor and to minimize the stray capacitances of the connections. This feature allows it to reach high energy resolution also at high count rates and near room temperature. The present work describes the structure and the performance of SDDs specially designed for high resolution spectroscopy with soft x rays at high detection rate. Experimental results of SDDs used in spectroscopy applications are also reported.

  11. Advanced AEM by Comprehensive Analysis and Modeling of System Drift

    Science.gov (United States)

    Schiller, Arnulf; Klune, Klaus; Schattauer, Ingrid

    2010-05-01

    The quality of the assessment of risks outgoing from environmental hazards strongly depends on the spatial and temporal distribution of the data collected in a survey area. Natural hazards generally emerge from wide areas as it is in the case of volcanoes or land slides. Conventional surface measurements are restricted to few lines or locations and often can't be conducted in difficult terrain. So they only give a spatial and temporary limited data set and therefore limit the reliability of risk analysis. Aero-geophysical measurements potentially provide a valuable tool for completing the data set as they can be performed over a wide area, even above difficult terrain within a short time. A most desirable opportunity in course of such measurements is the ascertainment of the dynamics of such potentially hazardous environmental processes. This necessitates repeated and reproducible measurements. Current HEM systems can't accomplish this adequately due to their system immanent drift and - in some cases - bad signal to noise ratio. So, to develop comprising concepts for advancing state of the art HEM-systems to a valuable tool for data acquisition in risk assessment or hydrological problems, different studies have been undertaken which form the contents of the presented work conducted in course of the project HIRISK (Helicopter Based Electromagnetic System for Advanced Environmental Risk Assessment - FWF L-354 N10, supported by the Austrian Science Fund). The methodology is based upon two paths: A - Comprehensive experimental testing on an existing HEM system serving as an experimental platform. B - The setup of a numerical model which is continuously refined according to the results of the experimental data. The model then serves to simulate the experimental as well as alternative configurations and to analyze them subject to their drift behavior. Finally, concepts for minimizing the drift are derived and tested. Different test series - stationary on ground as well

  12. Fully-coupled hydro-mechanical modelling of the D-holes and validation drift inflow

    International Nuclear Information System (INIS)

    Monsen, K.; Barton, N.; Makurat, A.

    1992-02-01

    This report presents the results from fully-coupled hydro-mechanical modelling of the D-hole and drift inflows. Joints represented in Harwells stochastically generated 8m x 8m x 8m cubes were used to select two possible joint geometries for two-dimensional rock mechanics simulations of the 2.8 x 2.2m validation drift, and the rock mass response to its excavation. The joints intersecting the four end faces of these cubes were set up in distinct element UDEC-BB models and loaded with boundary stresses of 10 MPa vertically and 14 MPa horizontally. In numerical models 5 and 8, which were run first as mechanical response (M) models (TR 91-05), full H-M coupling was performed, with calculations of inflow. In general, response to excavation was a little stronger than in hte un-coupled mechanical response (M) modelling. In the D-hole simulations, however, channel development int he disturbed zone could not occur due to less displacement taking place in the rock mass. For this reason, the stress levels were also generally much more moderate, preventing the joints from closing as much as in the drift simulations. Consequently, the D-hole model had a much better radial connectivity. It was possible to observe that the radial inflow to the D-holes was significantly higher than the flow into the drift models. However, due to the extremely small joint apertures involved (<1μm), time steps and calculation times were very slow in the H-M models, and although mechanical behaviour appeared to have reached equilibrium, there was evidence of continued transients in some of the flow regions. The drift excavation caused nearly total closing of critical joints due to local normal stress inceases. Near-blockage of fluid transportation routes was demonstrated. (au)

  13. Current trends in ion implantation

    International Nuclear Information System (INIS)

    Gwilliam, R.M.

    2001-01-01

    As semiconductor device dimensions continue to shrink, the drive beyond 250 nm is creating significant problems for the device processor. In particular, trends toward shallower-junctions, lower thermal budgets and simplified processing steps present severe challenges to ion implantation. In parallel with greater control of the implant process goes the need for a better understanding of the physical processes involved during implantation and subsequent activation annealing. For instance, the need for an understanding of dopant-defect interaction is paramount as defects mediate a number of technologically important phenomena such as transient enhanced diffusion and impurity gettering. This paper will outline the current trends in the ion implantation and some of the challenges it faces in the next decade, as described in the semiconductor roadmap. It will highlight some recent positron annihilation work that has made a contribution to addressing one of these challenges, namely the need for tighter control of implant uniformity and dose. Additionally, some vacancy-mediated processes are described with the implication that these may provide areas in which positron annihilation spectroscopy could make a significant contribution. (orig.)

  14. Drift curves from spray applications on commom bean crop

    Directory of Open Access Journals (Sweden)

    Mariana Rodrigues Bueno

    Full Text Available ABSTRACT In order to avoid the occurrence of drift in pesticide applications, it is fundamental to know the behavior of sprayed droplets. This study aimed to determine drift curves in pesticide applications on common bean crop under brazilian weather conditions, using different nozzle types and compared them with the "German" and "Dutch" drift prediction models. The experiment was conducted in Uberlândia, Minas Gerais/Brazil, in completely randomized design with ten replications and 4 x 20 split-plot arrangement in space. Drift deposited on collectors located over ground level was resulted by 150 L ha-1 carrier volume applications through four nozzle types (XR 11002 (fine droplets; AIXR 11002 (coarse droplets; TT 11002 (medium droplets; TTI 11002 (extremely coarse droplets, collected in 20 downwind distances, parallel to the crop line outside the target area, spaced by 2.5 m. The tracer rhodamine B was added to the spray to be quantified by fluorimetry. Drift prediction models adjusted by exponential functions were obtained considering the 90th percentile for XR, TT, AIXR and TTI nozzles. It is suggested to use the estimated drift models from this study for each nozzle type in drift prediction evaluations on bean crops under brazilian weather conditions.

  15. Relative drift between black aurora and the ionospheric plasma

    Directory of Open Access Journals (Sweden)

    E. M. Blixt

    2005-07-01

    Full Text Available Black auroras are recognized as spatially well-defined regions within uniform diffuse aurora where the optical emission is significantly reduced. Although a well studied phenomenon, there is no generally accepted theory for black auroras. One theory suggests that black regions are formed when energetic magnetospheric electrons no longer have access to the loss cone. If this blocking mechanism drifts with the source electron population in the magnetosphere, black auroras in the ionosphere should drift eastward with a velocity that increases with the energy of the precipitating electrons in the surrounding aurora, since the gradient-B curvature drift is energy dependent. It is the purpose of this paper to test this hypothesis. To do so we have used simultaneous measurements by the European Incoherent Scatter (EISCAT radar and an auroral TV camera at Tromsø, Norway. We have analyzed 8 periods in which a black aurora occurred frequently to determine their relative drift with respect to the ionospheric plasma. The black aurora was found to drift eastward with a velocity of 1.5–4km/s, which is in accordance with earlier observations. However, one case was found where a black patch was moving westward, this being the first report of such behaviour in the literature. In general, the drift was parallel to the ionospheric flow but at a much higher velocity. This suggests that the generating mechanism is not of ionospheric origin. The characteristic energy of the precipitating electron population was estimated through inversion of E-region plasma density profiles. We show that the drift speed of the black patches increased with the energy of the precipitating electrons in a way consistent with the gradient-B curvature drift, suggesting a magnetospheric mechanism for the black aurora. As expected, a comparison of the drift speeds with a rudimentary dipole field model of the gradient-B curvature drift speed only yields order-of-magnitude agreement, which

  16. Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model

    Science.gov (United States)

    Thran, Amanda C.; Dutkiewicz, Adriana; Spence, Paul; Müller, R. Dietmar

    2018-05-01

    Contourite drifts are anomalously high sediment accumulations that form due to reworking by bottom currents. Due to the lack of a comprehensive contourite database, the link between vigorous bottom water activity and drift occurrence has yet to be demonstrated on a global scale. Using an eddy-resolving ocean model and a new georeferenced database of 267 contourites, we show that the global distribution of modern contourite drifts strongly depends on the configuration of the world's most powerful bottom currents, many of which are associated with global meridional overturning circulation. Bathymetric obstacles frequently modify flow direction and intensity, imposing additional finer-scale control on drift occurrence. Mean bottom current speed over contourite-covered areas is only slightly higher (2.2 cm/s) than the rest of the global ocean (1.1 cm/s), falling below proposed thresholds deemed necessary to re-suspend and redistribute sediments (10-15 cm/s). However, currents fluctuate more frequently and intensely over areas with drifts, highlighting the role of intermittent, high-energy bottom current events in sediment erosion, transport, and subsequent drift accumulation. We identify eddies as a major driver of these bottom current fluctuations, and we find that simulated bottom eddy kinetic energy is over three times higher in contourite-covered areas in comparison to the rest of the ocean. Our work supports previous hypotheses which suggest that contourite deposition predominantly occurs due to repeated acute events as opposed to continuous reworking under average-intensity background flow conditions. This suggests that the contourite record should be interpreted in terms of a bottom current's susceptibility to experiencing periodic, high-speed current events. Our results also highlight the potential role of upper ocean dynamics in contourite sedimentation through its direct influence on deep eddy circulation.

  17. Simplified Drift Analysis for Proving Lower Bounds in Evolutionary Computation

    DEFF Research Database (Denmark)

    Oliveto, Pietro S.; Witt, Carsten

    2011-01-01

    Drift analysis is a powerful tool used to bound the optimization time of evolutionary algorithms (EAs). Various previous works apply a drift theorem going back to Hajek in order to show exponential lower bounds on the optimization time of EAs. However, this drift theorem is tedious to read...... and to apply since it requires two bounds on the moment-generating (exponential) function of the drift. A recent work identifies a specialization of this drift theorem that is much easier to apply. Nevertheless, it is not as simple and not as general as possible. The present paper picks up Hajek’s line...

  18. Drift data of the sea-gravity meter (SL-2) installed on the R/V Hakurei-maru; `Hakureimaru` senjo jurokei (SL-2) no drift ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Joshima, M [Geological Survey of Japan, Tsukuba (Japan); Ishihara, T [Japan National Oil Corp., Tokyo (Japan)

    1996-05-01

    This paper reports a rapid change in the drift of a sea-gravity meter SL-2 after 1987 and after its modification in 1993. In order to confirm the accuracy of the sea-gravity meter of the Hakurei-maru, changes in the lapse of time were summarized on the relative gravity value at the Funabashi base and on the drift rate in each voyage. The drift rates in the case of departing from and returning to Funabashi base were all less than 0.1mgal/day except the first year of 1987, which was presumably due to the growing stability of the gravimeter. The drift value of 1992 was 0.05mgal/day, producing an error of only 2mgal without drift compensation at the end of a 40 day voyage. The gravimeter after the total renewal of the control part in 1993 produced a large drift in the direction opposite to the conventional drift. The cause of these phenomena was supposed to be some kind of change in the spring property during the gap of one year; this large drift seemed to be settling down after the elapse of approximately one year. 4 refs., 8 figs., 2 tabs.

  19. Silicon drift-chamber studies for possible use at RHIC

    International Nuclear Information System (INIS)

    Humanic, T.J.

    1990-01-01

    It is proposed to continue the program now underway at the University of Pittsburgh to study the feasibility of using silicon drift-chambers as particle tracking devices at RHIC. We are currently testing a UA6-type detector obtained from BNL and plan to also study a new device that will become available this year: a cylindrical geometry detector designed for NA45 (CERN). In addition we propose to fabricate and study a detector to be used in vertex determination for the RHIC OASIS experiment. The two-year budget for this proposal is $246.962. 5 refs., 12 figs

  20. Ultra-low mass drift chambers

    International Nuclear Information System (INIS)

    Assiro, R.; Cappelli, L.; Cascella, M.; De Lorenzis, L.; Grancagnolo, F.; Ignatov, F.; L'Erario, A.; Maffezzoli, A.; Miccoli, A.; Onorato, G.; Perillo, M.; Piacentino, G.; Rella, S.; Rossetti, F.; Spedicato, M.; Tassielli, G.

    2013-01-01

    We present a novel low mass drift chamber concept, developed in order to fulfill the stringent requirements imposed by the experiments for extremely rare processes, which require high resolutions (order of 100–200 keV/c) for particle momenta in a range (50–100 MeV/c) totally dominated by the multiple scattering contribution. We describe a geometry optimization procedure and a new wiring strategy with a feed-through-less wire anchoring system developed and tested on a drift chamber prototype under completion at INFN-Lecce

  1. Test of a high resolution drift chamber prototype

    International Nuclear Information System (INIS)

    Comminchau, V.; Deutschmann, M.; Draheim, K.J.; Fritze, P.; Hangarter, K.; Hawelka, P.; Herten, U.; Tonutti, M.; Anderhub, H.; Fehlmann, J.; Hofer, H.; Klein, M.; Paradiso, J.A.; Schreiber, J.; Viertel, G.

    1984-06-01

    The performance of a drift chamber prototype for a colliding beam vertex detector in a test beam at DESY is described. At one (two) atmosphere gas pressure a spatial resolution of 40 μm (30 μm) per wire for one cm drift length was achieved with a 100 MHz Flash-ADC system. An excellent double track resolution of better than 300 μm over the full drift length of 5 cm can be estimated. (orig.)

  2. Diel drift of Chironomidae larvae in a pristine Idaho mountain stream

    Science.gov (United States)

    Tilley, L.J.

    1989-01-01

    Simultaneous hourly net collections in a meadow and canyon reach of a mountain stream determined diel and spatial abundances of drifting Chironomidae larvae. Sixty-one taxa were identified to the lowest practical level, 52 in the meadow and 41 in the canyon. Orthocladiinae was the most abundant subfamily with 32 taxa and a 24 h mean density of 294 individuals 100 m-3 (meadow) and 26 taxa and a mean of 648 individuals 100 m-3 (canyon). Chironominae was the second most abundant subfamily. Nonchironomid invertebrates at both sites and total Chironomidae larvae (meadow) were predominantly night-drifting. Parakiefferiella and Psectrocladius were day-drifting (meadow) whereas 8 other chironomid taxa (meadow) and 2 taxa (canyon) were night-drifting. All others were aperiodic or too rare to test periodicity, Stempellinella cf brevis Edwards exhibited catastrophic drift in the canyon only. The different drift patterns between sites is attributed to greater loss of streambed habitat in the canyon compared to the meadow as streamflow decreased. Consequent crowding of chironomid larvae in the canyon caused catastrophic drift or interfered with drift periodicty. This study adds to knowledge of Chironomidae drift and shows influences on drift of hydrologic and geomorphic conditions. ?? 1989 Kluwer Academic Publishers.

  3. In-Drift Precipitates/Salts Analysis

    International Nuclear Information System (INIS)

    Mariner, P.

    2001-01-01

    As directed by a written development plan (CRWMS M and O 1999a), an analysis of the effects of salts and precipitates on the repository chemical environment is to be developed and documented in an Analyses/Model Report (AMR). The purpose of this analysis is to assist Performance Assessment Operations (PAO) and the Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). The purpose of this ICN is to qualify and document qualification of the AMR's technical products. The scope of this document is to develop a model of the processes that govern salt precipitation and dissolution and resulting water composition in the Engineered Barrier System (EBS). This model is developed to serve as a basis for the in-drift geochemical modeling work performed by PAO and is to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. However, the concepts may also apply to some near and far field geochemical processes and can have conceptual application within the unsaturated zone and saturated zone transport modeling efforts. The intended use of the model developed in this report is to estimate, within an appropriate level of confidence, the pH, chloride concentration, and ionic strength of water on the drip shield or other location within the drift during the post-closure period. These estimates are based on evaporative processes that are subject to a broad range of potential environmental conditions and are independent of the presence or absence of backfill. An additional intended use is to estimate the environmental conditions required for complete vaporization of water. The presence and composition of liquid water

  4. In-Drift Precipitates/Salts Analysis

    Energy Technology Data Exchange (ETDEWEB)

    P. Mariner

    2001-01-10

    As directed by a written development plan (CRWMS M&O 1999a), an analysis of the effects of salts and precipitates on the repository chemical environment is to be developed and documented in an Analyses/Model Report (AMR). The purpose of this analysis is to assist Performance Assessment Operations (PAO) and the Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). The purpose of this ICN is to qualify and document qualification of the AMR's technical products. The scope of this document is to develop a model of the processes that govern salt precipitation and dissolution and resulting water composition in the Engineered Barrier System (EBS). This model is developed to serve as a basis for the in-drift geochemical modeling work performed by PAO and is to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. However, the concepts may also apply to some near and far field geochemical processes and can have conceptual application within the unsaturated zone and saturated zone transport modeling efforts. The intended use of the model developed in this report is to estimate, within an appropriate level of confidence, the pH, chloride concentration, and ionic strength of water on the drip shield or other location within the drift during the post-closure period. These estimates are based on evaporative processes that are subject to a broad range of potential environmental conditions and are independent of the presence or absence of backfill. An additional intended use is to estimate the environmental conditions required for complete vaporization of water. The presence and composition of liquid water

  5. Construction and test of a silicon drift chamber

    International Nuclear Information System (INIS)

    Holl, P.

    1985-06-01

    The present thesis presents the first fully applicable silicon detectors which work as drift chambers. Four different types of detectors were constructed. By a suitable geometry and electronic lay-out one- and two-dimensional position measurements were made possible. Chapter 2 describes function and construction of the detectors, chapter 3 their fabrication process. In chapter 4 construction and results of the test of a silicon drift chamber under laboratory conditions are described. By variation of the applied voltages the optimal operational conditions could be determined and material properties of the silicon, as for instance the electron mobility measured. A position resolution better than 5 μm at a drift length up to 4 mm was reached. Chapter 5 presents the results of the test of a silicon drift chamber under real experimental conditions in a particle beam of the super proton synchroton (SPS) of CERN. The best position resolution measured there is 10 μm. Chapter 6 summarizes the obtained results and discusses finally application possibilities and improvement proposals for silicon drift chambers. (orig./HSI) [de

  6. Extreme event statistics in a drifting Markov chain

    Science.gov (United States)

    Kindermann, Farina; Hohmann, Michael; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Widera, Artur

    2017-07-01

    We analyze extreme event statistics of experimentally realized Markov chains with various drifts. Our Markov chains are individual trajectories of a single atom diffusing in a one-dimensional periodic potential. Based on more than 500 individual atomic traces we verify the applicability of the Sparre Andersen theorem to our system despite the presence of a drift. We present detailed analysis of four different rare-event statistics for our system: the distributions of extreme values, of record values, of extreme value occurrence in the chain, and of the number of records in the chain. We observe that, for our data, the shape of the extreme event distributions is dominated by the underlying exponential distance distribution extracted from the atomic traces. Furthermore, we find that even small drifts influence the statistics of extreme events and record values, which is supported by numerical simulations, and we identify cases in which the drift can be determined without information about the underlying random variable distributions. Our results facilitate the use of extreme event statistics as a signal for small drifts in correlated trajectories.

  7. Parametric decay of lower hybrid wave into drift waves

    International Nuclear Information System (INIS)

    Sanuki, Heiji.

    1976-12-01

    A dispersion relation describing the parametric decay of a lower hybrid wave into an electrostatic drift wave and a drift Alfven wave is derived for an inhomogeneous magnetized plasma. Particularly the stimulated scattering of a drift Alfven wave in such a plasma was investigated in detail. The resonance backscattering instability is found to yield the minimum threshold. (auth.)

  8. Discovery of remarkable subpulse drifting pattern in PSR B0818-41

    Science.gov (United States)

    Bhattacharyya, B.; Gupta, Y.; Gil, J.; Sendyk, M.

    The study of pulsars showing systematic subpulse drift patterns provides important clues for understanding of pulsar emission mechanism. Pulsars with wide profiles provide extra insights because of the presence of multiple drift bands (e.g PSR B0826-34). We report the discovery of a remarkable subpulse drift pattern in a relatively less studied wide profile pulsar, PSR B0818-41, using the GMRT. We find simultaneous occurrence of three drift regions with two drift rates, an inner region with steeper apparent drift rate flanked on each side by a region of slower apparent drift rate. Furthermore, the two closely spaced drift regions always maintain a constant phase relationship. These unique drift properties seen for this pulsar is very rare. We interpret that the observed drift pattern is created by intersection of our line of sight (LOS) with two conal rings in a inner LOS (negative beta) geometry. We argue that the carousel rotation periodicity (P_4) and the number of sparks (N_sp) are the same for the rings and claim that P_4 is close to the measured P_3. Based on our analysis results and interpretations, we simulate the radiation from B0818-41. The simulations support our interpretations and reproduce the average profile and the observed drift pattern. The results of our study show that PSR B0818-41 is a powerful system to explore the pulsar radio emission mechanism, the implications of which are also discussed in our work.

  9. DRIFT-INDUCED PERPENDICULAR TRANSPORT OF SOLAR ENERGETIC PARTICLES

    International Nuclear Information System (INIS)

    Marsh, M. S.; Dalla, S.; Kelly, J.; Laitinen, T.

    2013-01-01

    Drifts are known to play a role in galactic cosmic ray transport within the heliosphere and are a standard component of cosmic ray propagation models. However, the current paradigm of solar energetic particle (SEP) propagation holds the effects of drifts to be negligible, and they are not accounted for in most current SEP modeling efforts. We present full-orbit test particle simulations of SEP propagation in a Parker spiral interplanetary magnetic field (IMF), which demonstrate that high-energy particle drifts cause significant asymmetric propagation perpendicular to the IMF. Thus in many cases the assumption of field-aligned propagation of SEPs may not be valid. We show that SEP drifts have dependencies on energy, heliographic latitude, and charge-to-mass ratio that are capable of transporting energetic particles perpendicular to the field over significant distances within interplanetary space, e.g., protons of initial energy 100 MeV propagate distances across the field on the order of 1 AU, over timescales typical of a gradual SEP event. Our results demonstrate the need for current models of SEP events to include the effects of particle drift. We show that the drift is considerably stronger for heavy ion SEPs due to their larger mass-to-charge ratio. This paradigm shift has important consequences for the modeling of SEP events and is crucial to the understanding and interpretation of in situ observations

  10. Multilevel Drift-Implicit Tau-Leap

    KAUST Repository

    Ben Hammouda, Chiheb

    2016-01-06

    The dynamics of biochemical reactive systems with small copy numbers of one or more reactant molecules is dominated by stochastic effects. For those systems, discrete state-space and stochastic simulation approaches were proved to be more relevant than continuous state-space and deterministic ones. In systems characterized by having simultaneously fast and slowtimescales, the existing discrete space-state stochastic path simulation methods such as the stochastic simulation algorithm (SSA) and the explicit tauleap method can be very slow. Implicit approximations were developed in the literature to improve numerical stability and provide efficient simulation algorithms for those systems. In this work, we propose an efficient Multilevel Monte Carlo method in the spirit of the work by Anderson and Higham (2012) that uses drift-implicit tau-leap approximations at levels where the explicit tauleap method is not applicable due to numerical stability issues. We present numerical examples that illustrate the performance of the proposed method.

  11. Optimization of curved drift tubes for ultraviolet-ion mobility spectrometry

    Science.gov (United States)

    Ni, Kai; Ou, Guangli; Zhang, Xiaoguo; Yu, Zhou; Yu, Quan; Qian, Xiang; Wang, Xiaohao

    2015-08-01

    Ion mobility spectrometry (IMS) is a key trace detection technique for toxic pollutants and explosives in the atmosphere. Ultraviolet radiation photoionization source is widely used as an ionization source for IMS due to its advantages of high selectivity and non-radioactivity. However, UV-IMS bring problems that UV rays will be launched into the drift tube which will cause secondary ionization and lead to the photoelectric effect of the Faraday disk. So air is often used as working gas to reduce the effective distance of UV rays, but it will limit the application areas of UV-IMS. In this paper, we propose a new structure of curved drift tube, which can avoid abnormally incident UV rays. Furthermore, using curved drift tube may increase the length of drift tube and then improve the resolution of UV-IMS according to previous research. We studied the homogeneity of electric field in the curved drift tube, which determined the performance of UV-IMS. Numerical simulation of electric field in curved drift tube was conducted by SIMION in our study. In addition, modeling method and homogeneity standard for electric field were also presented. The influences of key parameters include radius of gyration, gap between electrode as well as inner diameter of curved drift tube, on the homogeneity of electric field were researched and some useful laws were summarized. Finally, an optimized curved drift tube is designed to achieve homogenous drift electric field. There is more than 98.75% of the region inside the curved drift tube where the fluctuation of the electric field strength along the radial direction is less than 0.2% of that along the axial direction.

  12. The Storm Time Evolution of the Ionospheric Disturbance Plasma Drifts

    Science.gov (United States)

    Zhang, Ruilong; Liu, Libo; Le, Huijun; Chen, Yiding; Kuai, Jiawei

    2017-11-01

    In this paper, we use the C/NOFS and ROCSAT-1 satellites observations to analyze the storm time evolution of the disturbance plasma drifts in a 24 h local time scale during three magnetic storms driven by long-lasting southward IMF Bz. The disturbance plasma drifts during the three storms present some common features in the periods dominated by the disturbance dynamo. The newly formed disturbance plasma drifts are upward and westward at night, and downward and eastward during daytime. Further, the disturbance plasma drifts are gradually evolved to present significant local time shifts. The westward disturbance plasma drifts gradually migrate from nightside to dayside. Meanwhile, the dayside downward disturbance plasma drifts become enhanced and shift to later local time. The local time shifts in disturbance plasma drifts are suggested to be mainly attributed to the evolution of the disturbance winds. The strong disturbance winds arisen around midnight can constantly corotate to later local time. At dayside the westward and equatorward disturbance winds can drive the F region dynamo to produce the poleward and westward polarization electric fields (or the westward and downward disturbance drifts). The present results indicate that the disturbance winds corotated to later local time can affect the local time features of the disturbance dynamo electric field.

  13. Performance of silicon drift detectors in a magnetic field

    International Nuclear Information System (INIS)

    Castoldi, A.; Gatti, E.; Manzari, V.; Rehak, P.

    1997-01-01

    A study of the properties of silicon drift detectors in a magnetic field was carried out. A silicon drift detector with 41 anodes, providing unambiguous x and y position information, was used for measurements. Studies were done in three principal orientations of the detector relative to the direction of the magnetic field. The magnetic field was varied between 0 and 0.7 T and the drift field between 300 and 600 V/cm. Basic agreement with the theory of electron transport in semiconductors in a magnetic field was found. The transport properties of electrons in a magnetic field can be described by a mobility matrix. The components of the matrix depend on the electron mobility, Hall mobility and on the vector of the magnetic field. The precision of measurement was better than 0.2% for most of the parameters. For the electric field of a silicon drift detector, there is a first-order effect of the magnetic field only in one out of three principal directions. In this direction, the plane of the detector is perpendicular to the magnetic field and electrons drift at an angle α relative to the direction of the drift field. In two other principal directions, which are more important for tracking of the particles with drift detectors, there are no first-order magnetic effects. (orig.)

  14. Management of antithrombotic therapy during cardiac implantable device surgery.

    Science.gov (United States)

    AlTurki, Ahmed; Proietti, Riccardo; Birnie, David H; Essebag, Vidal

    2016-06-01

    Anticoagulants are commonly used drugs that are frequently encountered during device placement. Deciding when to halt or continue the use of anticoagulants is a balance between the risks of thromboembolism versus bleeding. Patients taking warfarin with a high risk of thromboembolism should continue to take their warfarin without interruption during device placement while ensuring their international normalized ratio remains below 3. For patients who are taking warfarin and have low risk of thromboembolism, either interrupted or continued warfarin may be used, with no evidence to clearly support either strategy. There is little evidence to support continuing direct acting oral anticoagulants (DOACs) for device implantation. The timing of halting these medications depends largely on renal function. If bleeding occurs, warfarin׳s anticoagulation effect is reversible with vitamin K and activated prothrombin complex concentrate. There are no DOAC reversal agents currently available, but some are under development. Regarding antiplatelet agents, aspirin alone can be safely continued while clopidogrel alone may also be continued, but with a slightly higher bleeding risk. Dual antiplatelet therapy for bare-metal stent/drug-eluting stent implanted within 4 weeks/6 months, respectively, should be continued due to high risk of stent thrombosis; however, if they are implanted after this period, then clopidogrel can be halted 5 days before the procedure and resumed soon after, while aspirin is continued. If the patient is taking both aspirin and warfarin, aspirin should be halted 5 days prior to the procedure, while warfarin is continued.

  15. Telemetric implantable pressure sensor for short- and long-term monitoring of intracranial pressure.

    Science.gov (United States)

    Frischholz, M; Sarmento, L; Wenzel, M; Aquilina, K; Edwards, R; Coakham, H B

    2007-01-01

    Patients with hydrocephalus, idiopathic intracranial hypertension and head injury frequently require monitoring of intracranial pressure (ICP) and may need repeated episodes of monitoring months or years apart. The gold standard for measurement of ICP remains the external ventricular catheter. This is a fluid-filled catheter transducer system that allows regular recalibration and correction of zero drift by its position relative to a fixed anatomical reference. It also allows drainage of cerebrospinal fluid (CSF), providing a means of lowering the ICP. Several catheter tip transducer systems are currently in clinical use, including using strain gauges or fiber-optical pressure sensing techniques. In these devices, zero drift and calibration cannot be checked in vivo. All the ICP monitoring devices in current clinical use require a physical connection between the brain and the external environment. This is a source of infection and limits the duration of monitoring. A number of telemetric monitoring devices, in which data is in some way transmitted transcutaneously, have been developed over the last twenty years, but significant technical problems have precluded their use in routine clinical practice. All current ICP monitors are temporary percutaneous implanted devices. Placement of these devices carries significant morbidity, particularly infection. Patients undergoing repeated monitoring require multiple surgical procedures. Apart from decreasing the risk of infection in patients with severe head injury, the clinical value of an accurate telemetric ICP monitoring system which maintains its reliability over a long period of implantation is high.

  16. Linear theory of drift-tearing and interchange modes in a screw pinch

    International Nuclear Information System (INIS)

    Copenhaver, C.

    1978-04-01

    A drift dispersion relation, as applied to a resistive incompressible plasma in a screw pinch, is derived. This dispersion relation incorporates both drift-tearing and drift-interchange modes and is valid throughout the collisional regime by including kinetic theory factors. The dispersion relation reduces to the drift-tearing dispersion relation in the zero pressure gradient limit, and to the classical resistive dispersion relation in the zero drift limit. The electron temperature gradient instability is still present. Now, however, the introduction of the interchange-drift instability increases the growth rate further above the tearing-drift case. (orig.) [de

  17. Electron Drift Properties in High Pressure Gaseous Xenon

    Energy Technology Data Exchange (ETDEWEB)

    Simón, A.; et al.

    2018-04-05

    Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White is a High Pressure Xenon gas TPC with electroluminescent amplification, a 1:2 scale model of the future NEXT-100 detector, which will be dedicated to neutrinoless double beta decay searches. NEXT-White has been operating at Canfranc Underground Laboratory (LSC) since December 2016. The drift parameters have been measured using $^{83m}$Kr for a range of reduced drift fields at two different pressure regimes, namely 7.2 bar and 9.1 bar. The results have been compared with Magboltz simulations. Agreement at the 5% level or better has been found for drift velocity, longitudinal diffusion and transverse diffusion.

  18. Seepage into drifts in unsaturated fractured rock at Yucca Mountain

    International Nuclear Information System (INIS)

    Birkholzer, Jens; Li, Guomin; Tsang, Chin-Fu; Tsang, Yvonne

    1998-01-01

    An important issue for the long-term performance of underground nuclear waste repository is the rate of seepage into the waste emplacement drifts. A prediction of the future seepage rate is particularly complicated for the potential repository site at Yucca Mountain, Nevada, as it is located in thick, partially saturated, fractured tuff formations. The long-term situation in the drifts several thousand years after waste emplacement will be characterized by a relative humidity level close to or equal to 100%, as the drifts will be sealed and unventilated, and the waste packages will have cooled. The underground tunnels will then act as capillary barriers for the unsaturated flow, ideally diverting water around them, if the capillary forces are stronger than gravity and viscous forces. Seepage into the drifts will only be possible if the hydraulic pressure in the rock close to the drift walls increases to positive values; i.e., the flow field becomes locally saturated. In the present work, they have developed and applied a methodology to study the potential rate of seepage into underground cavities embedded in a variably saturated, heterogeneous fractured rock formation. The fractured rock mass is represented as a stochastic continuum where the fracture permeabilities vary by several orders of magnitude. Three different realizations of random fracture permeability fields are generated, with the random permeability structure based on extensive fracture mapping, borehole video analysis, and in-situ air permeability testing. A 3-D numerical model is used to simulate the heterogeneous steady-state flow field around the drift, with the drift geometry explicitly represented within the numerical discretization grid. A variety of flow scenarios are considered assuming present-day and future climate conditions at Yucca Mountain. The numerical study is complemented by theoretical evaluations of the drift seepage problem, using stochastic perturbation theory to develop a better

  19. Correcting sample drift using Fourier harmonics.

    Science.gov (United States)

    Bárcena-González, G; Guerrero-Lebrero, M P; Guerrero, E; Reyes, D F; Braza, V; Yañez, A; Nuñez-Moraleda, B; González, D; Galindo, P L

    2018-07-01

    During image acquisition of crystalline materials by high-resolution scanning transmission electron microscopy, the sample drift could lead to distortions and shears that hinder their quantitative analysis and characterization. In order to measure and correct this effect, several authors have proposed different methodologies making use of series of images. In this work, we introduce a methodology to determine the drift angle via Fourier analysis by using a single image based on the measurements between the angles of the second Fourier harmonics in different quadrants. Two different approaches, that are independent of the angle of acquisition of the image, are evaluated. In addition, our results demonstrate that the determination of the drift angle is more accurate by using the measurements of non-consecutive quadrants when the angle of acquisition is an odd multiple of 45°. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. A drift chamber constructed of aluminized mylar tubes

    Science.gov (United States)

    Baringer, P.; Jung, C.; Ogren, H. O.; Rust, D. R.

    1987-03-01

    A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls.

  1. Silicon drift detectors, present and future prospects

    Science.gov (United States)

    Takahashi, J.; Bellwied, R.; Beuttenmuller, R.; Caines, H.; Chen, W.; Dyke, H.; Hoffmann, G. W.; Humanic, T.; Kotov, I.; Kuczewski, P.; Leonhardt, W.; Li, Z.; Lynn, D.; Minor, R.; Munhoz, M.; Ott, G.; Pandey, S. U.; Schambach, J.; Soja, R.; Sugarbaker, E.; Willson, R. M.

    2001-04-01

    Silicon drift detectors provide unambiguous two-dimensional position information for charged particle detection with a single detector layer. A large area silicon drift detector was developed for the inner tracking detector of the STAR experiment at RHIC. In this paper, we discuss the lessons learned and the future prospects of this technology.

  2. The F-Region Equatorial Ionospheric Electrodynamics Drifts ...

    African Journals Online (AJOL)

    The ionospheric plasma drift is one of the most essential parameters for understanding the dynamics of ionospheric F-region. F-region electromagnetic drifts are calculated for three seasonal conditions from ionosonde observations acquired during quiet period of a typical year of high and low solar activity at Ibadan (7.4oN, ...

  3. Spin-drift transport in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M Idrish [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong, Chittagong-4331 (Bangladesh)

    2008-02-07

    We present a study on spin transport in semiconductors under applied electric fields. Our experiments detect photoinjected electron spins and their relaxation during drift transport in intrinsic and moderately n-doped GaAs, based on the extraordinary Hall (eH) effect. For relatively low electric field (E), the optically spin-induced eH effect in n-doped GaAs is found to be enhanced with increasing doping density and not to depend much on E, indicating that a substantial amount of optical spin polarization is preserved during the drift transport in these extrinsic semiconductors. However, when the spin-oriented electrons are injected with a high E, a very significant decrease is observed in the eH voltage (V{sub eH}) due to an increase in the spin precession frequency of the hot electrons. Spin relaxation by the D'yakonov-Perel' mechanism is calculated, and is suggested to be the reason for such a rapid spin relaxation for hot electrons under a high E. However, in an intrinsic GaAs (i-GaAs), a much weaker V{sub eH} is observed and, as the electron spins scattered by holes due to the Coulomb interaction in i-GaAs, the spin relaxation by the Bir-Aronov-Pikus mechanism is considered. Skew scattering and side jump as possible mechanisms of the optically spin-induced transverse Hall currents are discussed. Based on a spin drift-diffusion model, drift and diffusion contributions to the V{sub eH} are examined. The results are also discussed in comparison with theoretical investigations.

  4. The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account

    Directory of Open Access Journals (Sweden)

    Russell Cohen Hoffing

    2018-02-01

    Full Text Available Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB, rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch. While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.

  5. A drift chamber constructed of aluminized mylar tubes

    International Nuclear Information System (INIS)

    Baringer, P.; Jung, C.; Ogren, H.O.; Rust, D.R.

    1987-01-01

    A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls. (orig.)

  6. Final predictions of ambient conditions along the east-west cross drift using the 3-D UZ site-scale model. Level 4 milestone SP33ABM4

    International Nuclear Information System (INIS)

    Ritcey, A.C.; Sonnenthal, E.L.; Wu, Y.S.; Haukwa, C.; Bodvarsson, G.S.

    1998-01-01

    In 1998, the Yucca Mountain Site Characterization Project (YMP) is expected to continue construction of an East-West Cross Drift. The 5-meter diameter drift will extend from the North Ramp of the Exploratory Studies Facility (ESF), near Station 19+92, southwest through the repository block, and over to and through the Solitario Canyon Fault. This drift is part of a program designed to enhance characterization of Yucca Mountain and to complement existing surface-based and ESF testing studies. The objective of this milestone is to use the three-dimensional (3-D) unsaturated zone (UZ) site-scale model to predict ambient conditions along the East-West Cross Drift. These predictions provide scientists and engineers with a priori information that can support design and construction of the East-West Cross Drift and associated testing program. The predictions also provide, when compared with data collected after drift construction, an opportunity to test and verify the calibration of the 3-D UZ site-scale model

  7. Looking for chemical reaction networks exhibiting a drift along a manifold of marginally stable states.

    Science.gov (United States)

    Brogioli, Doriano

    2013-02-07

    I recently reported some examples of mass-action equations that have a continuous manifold of marginally stable stationary states [Brogioli, D., 2010. Marginally stable chemical systems as precursors of life. Phys. Rev. Lett. 105, 058102; Brogioli, D., 2011. Marginal stability in chemical systems and its relevance in the origin of life. Phys. Rev. E 84, 031931]. The corresponding chemical reaction networks show nonclassical effects, i.e. a violation of the mass-action equations, under the effect of the concentration fluctuations: the chemical system drifts along the marginally stable states. I proposed that this effect is potentially involved in abiogenesis. In the present paper, I analyze the mathematical properties of mass-action equations of marginally stable chemical reaction networks. The marginal stability implies that the mass-action equations obey some conservation law; I show that the mathematical properties of the conserved quantity characterize the motion along the marginally stable stationary state manifold, i.e. they allow to predict if the fluctuations give rise to a random walk or a drift under the effect of concentration fluctuations. Moreover, I show that the presence of the drift along the manifold of marginally stable stationary-states is a critical property, i.e. at least one of the reaction constants must be fine tuned in order to obtain the drift. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Contraceptive implants: current perspectives

    Directory of Open Access Journals (Sweden)

    Rowlands S

    2014-09-01

    Full Text Available Sam Rowlands,1,2 Stephen Searle3 1Centre of Postgraduate Medical Research and Education, School of Health and Social Care, Bournemouth University, Bournemouth, United Kingdom; 2Dorset HealthCare, Bournemouth, United Kingdom; 3Sexual Health Services, Chesterfield, United KingdomAbstract: Progestin-only contraceptive implants are a highly cost-effective form of long-acting reversible contraception. They are the most effective reversible contraceptives and are of a similar effectiveness to sterilization. Pregnancies are rare in women using this method of contraception, and those that do occur must be fully investigated, with an ultrasound scan of the arm and serum etonogestrel level if the implant cannot be located. There are very few contraindications to use of implants, and they have an excellent safety profile. Both acceptability and continuation with the method are high. Noncontraceptive benefits include improvements in dysmenorrhea, ovulatory pain, and endometriosis. Problematic bleeding is a relatively common adverse effect that must be covered in preinsertion information-giving and supported adequately if it occurs. Recognized training for both insertion and removal should be undertaken. Care needs to be taken at both insertion and removal to avoid neurovascular injury. Implants should always be palpable; if they are not, noninsertion should be assumed until disproven. Etonogestrel implants are now radiopaque, which aids localization. Anticipated difficult removals should be performed by specially trained experts. Keywords: contraceptive, subdermal implant, etonogestrel, levonorgestrel, progestin-only, long-acting reversible contraception

  9. Minimum intervention dentistry: periodontics and implant dentistry.

    Science.gov (United States)

    Darby, I B; Ngo, L

    2013-06-01

    This article will look at the role of minimum intervention dentistry in the management of periodontal disease. It will discuss the role of appropriate assessment, treatment and risk factors/indicators. In addition, the role of the patient and early intervention in the continuing care of dental implants will be discussed as well as the management of peri-implant disease. © 2013 Australian Dental Association.

  10. Determining factors for implant referral rates.

    Science.gov (United States)

    Levin, Roger P

    2002-01-01

    The research findings indicate that the field of implant dentistry will only grow at a moderately low level unless certain changes are made. Findings indicated that the effort by the implant companies has been nothing short of dramatic, and yet almost 60% of restorative doctors do not participate annually in any implant case. There was no clear indication that younger restorative doctors will significantly increase the number of implant referrals, as their overall implant education has not dramatically differed from those dentists who graduated in earlier years. Once the research was completed, it became obvious to Levin Group that the driving force behind implant referral growth will be implant surgeons, because of their one-to-one relationship with restorative doctors. The Levin Group Implant Management and Marketing Consulting Program is based on approaching restorative doctors in several different levels, starting with awareness all the way through to case facilitation and long-term tracking and communication. Finally, a continuing marketing/education effort needs to be consistently in place with effective materials, not only to create a high level of awareness, but also to motivate restorative doctors to refer cases and then work through the case with the implant surgeon to a satisfactory completion for the restorative doctor, implant surgeon, and patient. While the surgical insertion of implants may seem to carry a high-profit margin relative to the restoration of implants, the truth is that the restoration of implants usually provides a 40% higher profit margin for the restorative doctor than traditional dental services. One of the key issues is that referring doctors have not necessarily learned how to set fees and present cases with regard to implant dentistry. The key factor here is to ensure that the patient understands that implant services involve higher fees than traditional services, because of the necessarily higher levels of experience, education

  11. Study and analysis of drift chamber parameters

    International Nuclear Information System (INIS)

    Martinez Laso, L.

    1988-01-01

    The present work deals mainly with drift chambers. In the first chapter a summary of drift chamber properties is presented. The information has been collected from the extensive bibliography available in this field. A very simple calculation procedure of drift chamber parameters has been developed and is presented in detail in the second chapter. Some prototypes have been made following two geometries (multidrift chamber and Z-chambers). Several installations have been used for test and calibration of these prototypes. A complete description of these installations is given in the third chapter. Cosmic rays, beta particles from a Ru106 radiactive source and a test beam in the WA (West Area) of SPS at CERN have been used for experimental purposes. The analysis and the results are described for the different setups. The experimental measurements have been used to produce a complete cell parametrization (position as function of drift time) and to obtain spatial resolution values (in the range of 200-250 um). Experimental results are in good agreement with numerical calculations. (Author)

  12. Nonlinear radial propagation of drift wave turbulence

    International Nuclear Information System (INIS)

    Prakash, M.

    1985-01-01

    We study the linear and the nonlinear radial propagation of drift wave energy in an inhomogeneous plasma. The drift mode excited in such a plasma is dispersive in nature. The drift wave energy spreads out symmetrically along the direction of inhomogeneity with a finite group velocity. To study the effect of the nonlinear coupling on the propagation of energy in a collision free plasma, we solve the Hasegawa-Mima equation as a mixed initial boundary-value problem. The solutions of the linearized equation are used to check the reliability of our numerical calculations. Additional checks are also performed on the invariants of the system. Our results reveal that a pulse gets distorted as it propagates through the medium. The peak of the pulse propagates with a finite velocity that depends on the amplitude of the initial pulse. The polarity of propagation depends on the initial parameters of the pulse. We have also studied drift wave propagation in a resistive plasma. The Hasegawa-Wakatani equations are used to investigate this problem

  13. Construction and operation of a drift-collection calorimeter

    International Nuclear Information System (INIS)

    Ambats, I.; Ayres, D.S.; Dawson, J.W.

    1984-01-01

    Large areas planar drift chambers with long drift distance (up to 50 cm) have been developed for possible use in the new Soudan 2 nucleon decay detector. Design goals included fine sampling to determine the topology of complex events with several low-energy tracks. The large scale of the experiment (> 1000 metric tons) required large area inexpensive chambers, which also had good position resolution and multi-track separation. The chambers were to be installed between thin sheets of steel to form a finegrained detector. A second goal was the sampling of dE/dx with each position measurement, in order to determine the direction and particle identity of each track. In this paper we report on the construction and operation of a prototype dectector consisting of 50 chambers, separated by 3 mm-thick steel plates. Readout of drift time and pulse height from anode wires and an orthogonal grid of bussed cathode pads utilized 6-bit flash ADC's. This application of the drift-collection calorimeter technique to a nucleon decay detector follows the investigation by a number of groups of calorimeters for high energy detectors based on long drifting

  14. Ocean modelling aspects for drift applications

    Science.gov (United States)

    Stephane, L.; Pierre, D.

    2010-12-01

    Nowadays, many authorities in charge of rescue-at-sea operations lean on operational oceanography products to outline research perimeters. Moreover, current fields estimated with sophisticated ocean forecasting systems can be used as input data for oil spill/ adrift object fate models. This emphasises the necessity of an accurate sea state forecast, with a mastered level of reliability. This work focuses on several problems inherent to drift modeling, dealing in the first place with the efficiency of the oceanic current field representation. As we want to discriminate the relevance of a particular physical process or modeling option, the idea is to generate series of current fields of different characteristics and then qualify them in term of drift prediction efficiency. Benchmarked drift scenarios were set up from real surface drifters data, collected in the Mediterranean sea and off the coasts of Angola. The time and space scales that we are interested in are about 72 hr forecasts (typical timescale communicated in case of crisis), for distance errors that we hope about a few dozen of km around the forecast (acceptable for reconnaissance by aircrafts) For the ocean prediction, we used some regional oceanic configurations based on the NEMO 2.3 code, nested into Mercator 1/12° operational system. Drift forecasts were computed offline with Mothy (Météo France oil spill modeling system) and Ariane (B. Blanke, 1997), a Lagrangian diagnostic tool. We were particularly interested in the importance of the horizontal resolution, vertical mixing schemes, and any processes that may impact the surface layer. The aim of the study is to ultimately point at the most suitable set of parameters for drift forecast use inside operational oceanic systems. We are also motivated in assessing the relevancy of ensemble forecasts regarding determinist predictions. Several tests showed that mis-described observed trajectories can finally be modelled statistically by using uncertainties

  15. OpenDrift v1.0: a generic framework for trajectory modelling

    Science.gov (United States)

    Dagestad, Knut-Frode; Röhrs, Johannes; Breivik, Øyvind; Ådlandsvik, Bjørn

    2018-04-01

    OpenDrift is an open-source Python-based framework for Lagrangian particle modelling under development at the Norwegian Meteorological Institute with contributions from the wider scientific community. The framework is highly generic and modular, and is designed to be used for any type of drift calculations in the ocean or atmosphere. A specific module within the OpenDrift framework corresponds to a Lagrangian particle model in the traditional sense. A number of modules have already been developed, including an oil drift module, a stochastic search-and-rescue module, a pelagic egg module, and a basic module for atmospheric drift. The framework allows for the ingestion of an unspecified number of forcing fields (scalar and vectorial) from various sources, including Eulerian ocean, atmosphere and wave models, but also measurements or a priori values for the same variables. A basic backtracking mechanism is inherent, using sign reversal of the total displacement vector and negative time stepping. OpenDrift is fast and simple to set up and use on Linux, Mac and Windows environments, and can be used with minimal or no Python experience. It is designed for flexibility, and researchers may easily adapt or write modules for their specific purpose. OpenDrift is also designed for performance, and simulations with millions of particles may be performed on a laptop. Further, OpenDrift is designed for robustness and is in daily operational use for emergency preparedness modelling (oil drift, search and rescue, and drifting ships) at the Norwegian Meteorological Institute.

  16. Electromagnetic drift modes in an inhomogeneous electron gas

    DEFF Research Database (Denmark)

    Shukla, P. K.; Pecseli, H. L.; Juul Rasmussen, Jens

    1986-01-01

    A pair of nonlinear equations is derived which describes the dynamics of the electromagnetic drift oscillations in a nonuniform magnetized electron gas. It is shown that the nonlinear electromagnetic drift modes can propagate in the form of dipole vortices...

  17. Strange Attractors in Drift Wave Turbulence

    International Nuclear Information System (INIS)

    Lewandowski, J.L.V.

    2003-01-01

    A multi-grid part-in-cell algorithm for a shearless slab drift wave model with kinetic electrons is presented. The algorithm, which is based on an exact separation of adiabatic and nonadiabatic electron responses, is used to investigate the presence of strange attractors in drift wave turbulence. Although the simulation model has a large number of degrees of freedom, it is found that the strange attractor is low-dimensional and that it is strongly affected by dissipative (collisional) effects

  18. Ion implantation control system

    International Nuclear Information System (INIS)

    Gault, R. B.; Keutzer, L. L.

    1985-01-01

    A control system is disclosed for an ion implantation system of the type in which the wafers to be implanted are mounted around the periphery of a disk which rotates and also moves in a radial direction relative to an ion beam to expose successive sections of each wafer to the radiation. The control system senses beam current which passes through one or more apertures in the disk and is collected by a Faraday cup. This current is integrated to obtain a measure of charge which is compared with a calculated value based upon the desired ion dosage and other parameters. The resultant controls the number of incremental steps the rotating disk moves radially to expose the adjacent sections of each wafer. This process is continued usually with two or more traverses until the entire surface of each wafer has been implanted with the proper ion dosage

  19. The drift velocity monitoring system of the CMS barrel muon chambers

    CERN Document Server

    Altenhoefer, Georg Friedrich; Heidemann, Carsten Andreas; Reithler, Hans; Sonnenschein, Lars; Teyssier, Daniel Francois

    2017-01-01

    The drift velocity is a key parameter of drift chambers. Its value depends on several parameters: electric field, pressure, temperature, gas mixture, and contamination, for example, by ambient air. A dedicated Velocity Drift Chamber (VDC) with 1-L volume has been built at the III. Phys. Institute A, RWTH Aachen, in order to monitor the drift velocity of all CMS barrel muon Drift Tube chambers. A system of six VDCs was installed at CMS and has been running since January 2011. We present the VDC monitoring system, its principle of operation, and measurements performed.

  20. The drift velocity monitoring system of the CMS barrel muon chambers

    Science.gov (United States)

    Altenhöfer, Georg; Hebbeker, Thomas; Heidemann, Carsten; Reithler, Hans; Sonnenschein, Lars; Teyssier, Daniel

    2018-04-01

    The drift velocity is a key parameter of drift chambers. Its value depends on several parameters: electric field, pressure, temperature, gas mixture, and contamination, for example, by ambient air. A dedicated Velocity Drift Chamber (VDC) with 1-L volume has been built at the III. Phys. Institute A, RWTH Aachen, in order to monitor the drift velocity of all CMS barrel muon Drift Tube chambers. A system of six VDCs was installed at CMS and has been running since January 2011. We present the VDC monitoring system, its principle of operation, and measurements performed.

  1. Implantable Cardiac Pacemakers – 50 Years from the First Implantation

    Directory of Open Access Journals (Sweden)

    Ratko Magjarević

    2010-01-01

    Overview: Development of implantable cardiac pacemaker was enabled by another important invention, the silicon transistor. h ough the invention of suitable lithium cells as appropriate power supply was essential for prolongation of battery life cycle and for increased reliability of pacemakers, main milestones in the development were associated with technological breakthroughs in electronics: from transistors, which introduced such features as small size and low power consumption, to hybrid and integrated circuits, which enabled programmability, microprocessors, which added more options in programming (multiprogrammability, diagnostics and telemetry, and the ICT (information communication technology that enabled physicians remote access to patients and interrogation of their implantable devices. Conclusions: Implantable pacemakers are reliable devices indicated for a wide range of dif erent therapies of cardiac rhythm disorders and heart failure. h ere is still a lot to learn about the physiology of a normal heart and even more about the failing heart. Modern pacemakers provide physicians valuable information from pacemakers’ memory via the built-in telemetry system. h ese information help physicians to better understand pathologic processes within the heart, thus contributing to the development of new ideas for treatment of diseases and for precise tailoring of the therapy to the patient’s needs. Although implantable pacemakers have reached the level of mature technology, they will continue to develop with therapies and diagnostics to facilitate a higher quality of life.

  2. MALDI-TOF Baseline Drift Removal Using Stochastic Bernstein Approximation

    Directory of Open Access Journals (Sweden)

    Howard Daniel

    2006-01-01

    Full Text Available Stochastic Bernstein (SB approximation can tackle the problem of baseline drift correction of instrumentation data. This is demonstrated for spectral data: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF data. Two SB schemes for removing the baseline drift are presented: iterative and direct. Following an explanation of the origin of the MALDI-TOF baseline drift that sheds light on the inherent difficulty of its removal by chemical means, SB baseline drift removal is illustrated for both proteomics and genomics MALDI-TOF data sets. SB is an elegant signal processing method to obtain a numerically straightforward baseline shift removal method as it includes a free parameter that can be optimized for different baseline drift removal applications. Therefore, research that determines putative biomarkers from the spectral data might benefit from a sensitivity analysis to the underlying spectral measurement that is made possible by varying the SB free parameter. This can be manually tuned (for constant or tuned with evolutionary computation (for .

  3. Dimethylether: a low velocity, low diffusion drift chamber gas

    International Nuclear Information System (INIS)

    Villa, F.

    1983-01-01

    There are two main motivations to look for a low electron mobility gas: the first is that a low drift velocity relaxes the need to measure drift times with nanosecond (or even subnanosecond) precision; the second is that (in an ideal drift geometry), the capability of resolving two closely spaced tracks depends upon the ratio of electron mobility to ion mobility μ/sub e//μ/sub i/. Since μ/sub i/ is rather constant, the way to separate two tracks is to slow down the electrons. Many other properties are required besides low mobility and low drifting electron temperature: the gas should have a large (> 10 3 ) stable gain; it must be chemically stable and not oxic; it should not attack materials commonly used to fabricate drift chambers, etc. With these requirements in mind, we have tried a few promising (on paper) gases, either pure or in admixture with Argon. One of the gases examined, dimethylether [(CH 3 ) 2 )], has shown interesting characteristics

  4. Investigation of long drift chambers for a nucleon-decay detector

    International Nuclear Information System (INIS)

    Price, L.E.; Dawson, J.; Ayres, D.; Denis, R.S.

    1981-01-01

    The use of long drift chambers for a nucleon-decay detector is discussed as a means of achieving a detector with very fine tracking, but with a modest number of readout channels. Strategies for reducing the attenuation of drifting electrons are considered, particularly the necessity of shaping the electric field to reduce the effects of diffusion and of nearby grounded conductors. Measured results are presented for a chamber with 1 cm drift gap and 50 cm maximum drift distance. The measured attenuation is 12%

  5. Site characterization and validation - Inflow to the validation drift

    International Nuclear Information System (INIS)

    Harding, W.G.C.; Black, J.H.

    1992-01-01

    Hydrogeological experiments have had an essential role in the characterization of the drift site on the Stripa project. This report focuses on the methods employed and the results obtained from inflow experiments performed on the excavated drift in stage 5 of the SCV programme. Inflows were collected in sumps on the floor, in plastic sheeting on the upper walls and ceiling, and measured by means of differential humidity of ventilated air at the bulkhead. Detailed evaporation experiments were also undertaken on uncovered areas of the excavated drift. The inflow distribution was determined on the basis of a system of roughly equal sized grid rectangles. The results have highlighted the overriding importance of fractures in the supply of water to the drift site. The validation drift experiment has revealed that in excess of 99% of inflow comes from a 5 m section corresponding to the 'H' zone, and that as much as 57% was observed coming from a single grid square (267). There was considerable heterogeneity even within the 'H' zone, with 38% of such samples areas yielding no flow at all. Model predictions in stage 4 underestimated the very substantial declines in inflow observed in the validation drift when compared to the SDE; this was especially so in the 'good' rock areas. Increased drawdowns in the drift have generated less flow and reduced head responses in nearby boreholes by a similar proportion. This behaviour has been the focus for considerable study in the latter part of the SCV project, and a number of potential processes have been proposed. These include 'transience', stress redistribution resulting from the creation of the drift, chemical precipitation, blast-induced dynamic unloading and related gas intrusion, and degassing. (au)

  6. Nonlinear excitation of geodesic acoustic modes by drift waves

    International Nuclear Information System (INIS)

    Chakrabarti, N.; Singh, R.; Kaw, P. K.; Guzdar, P. N.

    2007-01-01

    In this paper, two mode-coupling analyses for the nonlinear excitation of the geodesic acoustic modes (GAMs) in tokamak plasmas by drift waves are presented. The first approach is a coherent parametric process, which leads to a three-wave resonant interaction. This investigation allows for the drift waves and the GAMs to have comparable scales. The second approach uses the wave-kinetic equations for the drift waves, which then couples to the GAMs. This requires that the GAM scale length be large compared to the wave packet associated with the drift waves. The resonance conditions for these two cases lead to specific predictions of the radial wave number of the excited GAMs

  7. Current use of implantable electrical devices in Sweden: data from the Swedish pacemaker and implantable cardioverter-defibrillator registry.

    Science.gov (United States)

    Gadler, Fredrik; Valzania, Cinzia; Linde, Cecilia

    2015-01-01

    The National Swedish Pacemaker and Implantable Cardioverter-Defibrillator (ICD) Registry collects prospective data on all pacemaker and ICD implants in Sweden. We aimed to report the 2012 findings of the Registry concerning electrical devices implantation rates and changes over time, 1 year complications, long-term device longevity and patient survival. Forty-four Swedish implanting centres continuously contribute implantation of pacemakers and ICDs to the Registry by direct data entry on a specific website. Clinical and technical information on 2012 first implants and postoperative complications were analysed and compared with previous years. Patient survival data were obtained from the Swedish population register database. In 2012, the mean pacemaker and ICD first implantation rates were 697 and 136 per million inhabitants, respectively. The number of cardiac resynchronization therapy (CRT) first implantations/million capita was 41 (CRT pacemakers) and 55 (CRT defibrillators), with only a slight increase in CRT-ICD rate compared with 2011. Most device implantations were performed in men. Complication rates for pacemaker and ICD procedures were 5.3 and 10.1% at 1 year, respectively. Device and lead longevity differed among manufacturers. Pacemaker patients were older at the time of first implant and had generally worse survival rate than ICD patients (63 vs. 82% after 5 years). Pacemaker and ICD implantation rates seem to have reached a level phase in Sweden. Implantable cardioverter-defibrillator and CRT implantation rates are very low and do not reflect guideline indications. Gender differences in CRT and ICD implantations are pronounced. Device and patient survival rates are variable, and should be considered when deciding device type. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  8. Prediction of littoral drift with artificial neural networks

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.K.; Deo, M.C.; SanilKumar, V.

    of the rate of sand drift has still remained as a problem. The current study addresses this issue through the use of artificial neural networks (ANN). Feed forward networks were developed to predict the sand drift from a variety of causative variables...

  9. Drift tube suspension for high intensity linear accelerators

    International Nuclear Information System (INIS)

    Clark, D.C.; Frank, J.A.; Liska, D.J.; Potter, R.C.; Schamaun, R.G.

    1982-01-01

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder

  10. Drift tube suspension for high intensity linear accelerators

    Science.gov (United States)

    Liska, Donald J.; Schamaun, Roger G.; Clark, Donald C.; Potter, R. Christopher; Frank, Joseph A.

    1982-01-01

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  11. Shear wall ultimate drift limits

    International Nuclear Information System (INIS)

    Duffey, T.A.; Goldman, A.; Farrar, C.R.

    1994-04-01

    Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated

  12. OpenDrift v1.0: a generic framework for trajectory modelling

    Directory of Open Access Journals (Sweden)

    K.-F. Dagestad

    2018-04-01

    Full Text Available OpenDrift is an open-source Python-based framework for Lagrangian particle modelling under development at the Norwegian Meteorological Institute with contributions from the wider scientific community. The framework is highly generic and modular, and is designed to be used for any type of drift calculations in the ocean or atmosphere. A specific module within the OpenDrift framework corresponds to a Lagrangian particle model in the traditional sense. A number of modules have already been developed, including an oil drift module, a stochastic search-and-rescue module, a pelagic egg module, and a basic module for atmospheric drift. The framework allows for the ingestion of an unspecified number of forcing fields (scalar and vectorial from various sources, including Eulerian ocean, atmosphere and wave models, but also measurements or a priori values for the same variables. A basic backtracking mechanism is inherent, using sign reversal of the total displacement vector and negative time stepping. OpenDrift is fast and simple to set up and use on Linux, Mac and Windows environments, and can be used with minimal or no Python experience. It is designed for flexibility, and researchers may easily adapt or write modules for their specific purpose. OpenDrift is also designed for performance, and simulations with millions of particles may be performed on a laptop. Further, OpenDrift is designed for robustness and is in daily operational use for emergency preparedness modelling (oil drift, search and rescue, and drifting ships at the Norwegian Meteorological Institute.

  13. Ponderomotive modification of drift tearing modes

    International Nuclear Information System (INIS)

    Urquijo, G.; Singh, R.; Sen, A.

    1997-01-01

    The linear characteristics of drift tearing modes are investigated in the presence of a significant background of radio-frequency (RF) waves in the ion cyclotron range of frequencies. The ponderomotive force, arising from the radial gradients in the RF field energy, is found to significantly modify the inner layer solutions of the drift tearing modes. It can have a stabilizing influence, even at moderate RF powers, provided the field energy has a decreasing radial profile at the mode rational surface. (author)

  14. Dynamics of zonal flows and self-regulating drift-wave turbulence

    International Nuclear Information System (INIS)

    Diamond, P.H.; Fleischer, J.; Rosenbluth, M.N.; Hinton, F.L.; Malkov, M.; Smolyakov, A.

    1999-01-01

    We present a theory of zonal flow - drift wave dynamics. Zonal flows are generated by modulational instability of a drift wave spectrum, and are damped by collisions. Drift waves undergo random shearing-induced refraction, resulting in increased mean square radial wavenumber. Drift waves and zonal flows together form a simple dynamical system, which has a single stable fixed point. In this state, the fluctuation intensity and turbulent diffusivity are ultimately proportional to the collisional zonal flow damping. The implications of these results for transport models is discussed. (author)

  15. Dynamics of zonal flows and self-regulating drift-wave turbulence

    International Nuclear Information System (INIS)

    Diamond, P.H.; Fleischer, J.; Rosenbluth, M.; Hinton, F.L.; Malkov, M.; Smolyakov, A.

    2001-01-01

    We present a theory of zonal flow - drift wave dynamics. Zonal flows are generated by modulational instability of a drift wave spectrum, and are damped by collisions. Drift waves undergo random shearing-induced refraction, resulting in increased mean square radial wavenumber. Drift waves and zonal flows together form a simple dynamical system, which has a single stable fixed point. In this state, the fluctuation intensity and turbulent diffusivity are ultimately proportional to the collisional zonal flow damping. The implications of these results for transport models is discussed. (author)

  16. Optical and Electrical Properties of Ar+ Implanted PET

    Science.gov (United States)

    Kumar, Rajiv; Shekhawat, Nidhi; Sharma, Annu; Aggarwal, Sanjeev; Kumar, Praveen; Kanjilal, D.

    2011-07-01

    In the present work, the effect of 100 keV argon ion implantation on the optical and electrical properties of PET has been studied. A continuous reduction in optical band gap (from 3.63 to 1.93 eV) with increasing implantation dose has been observed as analyzed using UV-Visible absorption spectroscopy. Current-Voltage (I-V) characteristics have been studied which clearly indicate the enhancement in the conductivity of PET specimens as an effect of implantation. This increase in conductivity has been correlated with the decrease in optical band gap.

  17. A conceptual knowledge-link model for supporting dental implant process

    OpenAIRE

    Szejka , Anderson Luis; Canciglieri , Osiris ,; Rudek , Marcelo; Panetto , Hervé

    2014-01-01

    International audience; Computer aided techniques widely used as diagnostic and surgical procedures tools are scarcely applied in implantology, which continues using visualization of CT images to define the parameters for dental implant process leaving to the dentist discretion the implant determination, since only the images analysis is non-deterministic. Thus, this research proposes the development of a knowledge-link model integrated to a reasoner system to support dental implant process t...

  18. Image-guided navigation system for placing dental implants.

    Science.gov (United States)

    Casap, Nardy; Wexler, Alon; Lustmann, Joshua

    2004-10-01

    Navigation-guided surgery has recently been introduced into various surgical disciplines, including oral and maxillofacial surgery. Since the advent of dental implants, dental computed tomography (CT) scans have been used as a diagnostic tool for preoperative planning, but not as part of the surgical phase. This article explains the principles of computer-assisted surgery and describes the use of a computer-guided navigation system in dental implantology. The system uses preoperative dental CT scans for planning and as an integral part of the surgical procedure. This system allows continuous intraoperative coordination of the implantation phase with the preoperative plan, optimizing the accuracy of implant surgery. Deviations from the planned location of the implants are minimal. Several cases are discussed.

  19. Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, F. G.; Hanna, S. R.; Parr, P. D.

    1978-12-01

    The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified with concentrations in plant materials (fescue grass) decreasing with increasing distance from the cooling tower. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. Results suggest that differences in retention in litter and foliage are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil-water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Preliminary model estimates of drift deposition are compared to deposition measurements.

  20. Nearshore drift dynamics of natural versus artificial seagrass wrack

    Science.gov (United States)

    Baring, Ryan J.; Fairweather, Peter G.; Lester, Rebecca E.

    2018-03-01

    Drifting macrophytes such as seagrass and macroalgae are commonly found washed ashore on sandy beaches but few studies have investigated the drift trajectories of macrophytes whilst near to the coast. This is the first study to investigate the surface drifting of small clumps of seagrass released at various distances from shore, across multiple days with contrasting wind and tidal conditions, in a large gulf in southern Australia. Natural and artificial radio-tagged seagrass units generally travelled in the same directions as tides but trajectories were variable across sampling days and when tagged units were released at different distances from shore. Natural and artificial units diverged from each other particularly on days when wind speeds increased but generally drifted in the same direction and ended up within close proximity to each other at the 6-h endpoint. During calm conditions, tagged seagrass units drifted with tides for 0.25-5 km and, during one sampling day when wind speeds increased, drifted for >5 km over the 6-h time period. Only tagged units that were released closest to shore stranded on sandy beaches within the six hours of observation, so it would be difficult to predict the eventual stranding location on shorelines for macrophytes released further offshore. This study provides evidence of the variability of macrophyte drift dynamics near to coastlines. Acknowledging this variability is essential for further understanding of the ecological significance of allochthonous material arriving at shorelines, which should be integrated into future research and management of sandy-beach ecosystems.

  1. Terminal Posterior Tilted Implants Planned as a Sinus Graft Alternative for Fixed Full-Arch Implant-Supported Maxillary Restoration: A Case Series with 10- to 19-Year Results on 44 Consecutive Patients Presenting for Routine Maintenance.

    Science.gov (United States)

    Fortin, Yvan; Sullivan, Richard M

    2017-02-01

    Posterior maxillary tilted implants are gaining prevalence as an alternative to sinus grafts supporting fixed maxillary restorations. This paper reports long-term results after loading using this technique. Consecutive patients presenting for either routine hygiene maintenance or unplanned emergency care who had received tilted implants as a sinus graft alternative to support fixed fully implant-supported restoration of an edentulous maxilla and were followed for a minimum of 10 years from initial implant placement were included in this evaluation. Forty-four patients were identified: 40 with bilateral tilted implants and 4 with one tilted and one axial posterior implant. Eight patients received one-piece fixed porcelain-to-gold screw-retained restorations, and thirty-six patients received a fully implant-supported patient-removable Marius Bridge. Seventy-nine out of 84 originally loaded posterior tilted implants survived a minimum of 10 years loading; one tilted implant was lost at 10 years. Eight additional posterior implants were placed for either these lost tilted posterior implants or as proactive supplemental support; one of these replacement tilted implants survived for at least 10 years and is included in the data. All patients have maintained continuous fixed function throughout the follow-up period. Forty-one out of 44 patients continue with the original restoration, 33 without modification or removal of the fixed restoration or implant-connecting bar. One porcelain-to-gold and seven Marius Bridges had framework modifications to accommodate additional implants; 3 Marius Bridge restorations were replaced with a newer generation. Within the limits of this retrospective study, the results show that continuous fixed function of fully implant-supported maxillary restorations using posterior tilted implants in terminal positions of support as a sinus graft alternative combined with axial anterior implants is possible over a prolonged period. Loss of a posterior

  2. Drift Compression and Final Focus Options for Heavy Ion Fusion

    International Nuclear Information System (INIS)

    Hong Qin; Davidson, Ronald C.; Barnard, John J.; Lee, Edward P.

    2005-01-01

    A drift compression and final focus lattice for heavy ion beams should focus the entire beam pulse onto the same focal spot on the target. We show that this requirement implies that the drift compression design needs to satisfy a self-similar symmetry condition. For un-neutralized beams, the Lie symmetry group analysis is applied to the warm-fluid model to systematically derive the self-similar drift compression solutions. For neutralized beams, the 1-D Vlasov equation is solved explicitly, and families of self-similar drift compression solutions are constructed. To compensate for the deviation from the self-similar symmetry condition due to the transverse emittance, four time-dependent magnets are introduced in the upstream of the drift compression such that the entire beam pulse can be focused onto the same focal spot

  3. Drift of suspended ferromagnetic particles due to the Magnus effect

    Science.gov (United States)

    Denisov, S. I.; Pedchenko, B. O.

    2017-01-01

    A minimal system of equations is introduced and applied to study the drift motion of ferromagnetic particles suspended in a viscous fluid and subjected to a time-periodic driving force and a nonuniformly rotating magnetic field. It is demonstrated that the synchronized translational and rotational oscillations of these particles are accompanied by their drift in a preferred direction, which occurs under the action of the Magnus force. We calculate both analytically and numerically the drift velocity of particles characterized by single-domain cores and nonmagnetic shells and show that there are two types of drift, unidirectional and bidirectional, which can be realized in suspensions composed of particles with different core-shell ratios. The possibility of using the phenomenon of bidirectional drift for the separation of core-shell particles in suspensions is also discussed.

  4. Learning From Short Text Streams With Topic Drifts.

    Science.gov (United States)

    Li, Peipei; He, Lu; Wang, Haiyan; Hu, Xuegang; Zhang, Yuhong; Li, Lei; Wu, Xindong

    2017-09-18

    Short text streams such as search snippets and micro blogs have been popular on the Web with the emergence of social media. Unlike traditional normal text streams, these data present the characteristics of short length, weak signal, high volume, high velocity, topic drift, etc. Short text stream classification is hence a very challenging and significant task. However, this challenge has received little attention from the research community. Therefore, a new feature extension approach is proposed for short text stream classification with the help of a large-scale semantic network obtained from a Web corpus. It is built on an incremental ensemble classification model for efficiency. First, more semantic contexts based on the senses of terms in short texts are introduced to make up of the data sparsity using the open semantic network, in which all terms are disambiguated by their semantics to reduce the noise impact. Second, a concept cluster-based topic drifting detection method is proposed to effectively track hidden topic drifts. Finally, extensive studies demonstrate that as compared to several well-known concept drifting detection methods in data stream, our approach can detect topic drifts effectively, and it enables handling short text streams effectively while maintaining the efficiency as compared to several state-of-the-art short text classification approaches.

  5. Surface modifications of dental implants.

    Science.gov (United States)

    Stanford, C M

    2008-06-01

    Dental implant surface technologies have been evolving rapidly to enhance a more rapid bone formation on their surface and hold a potential to increase the predictability of expedited implant therapy. While implant outcomes have become highly predictable, there are sites and conditions that result in elevated implant loss. This paper reviews the impact of macro-retentive features which includes approaches to surface oxide modification, thread design, press-fit and sintered-bead technologies to increase predictability of outcomes. Implant designs that lead to controlled lateral compression of the bone can improve primary stability as long as the stress does not exceed the localized yield strength of the cortical bone. Some implant designs have reduced crestal bone loss by use of multiple cutting threads that are closely spaced, smoothed on the tip but designed to create a hoop-stress stability of the implant as it is completely seated in the osteotomy. Following the placement of the implant, there is a predictable sequence of bone turnover and replacement at the interface that allows the newly formed bone to adapt to microscopic roughness on the implant surface, and on some surfaces, a nanotopography (<10(-9) m scale) that has been shown to preferably influence the formation of bone. Newly emerging studies show that bone cells are exquisitely sensitive to these topographical features and will upregulate the expression of bone related genes for new bone formation when grown on these surfaces. We live in an exciting time of rapid changes in the modalities we can offer patients for tooth replacement therapy. Given this, it is our responsibility to be critical when claims are made, incorporate into our practice what is proven and worthwhile, and to continue to support and provide the best patient care possible.

  6. Non-Linear MDT Drift Gases like Ar/CO2

    CERN Document Server

    Aleksa, Martin

    1998-01-01

    Detailed measurements and simulations have been performed, investigating the properties of Ar/CO2 mixtures as a MDT drift gas. This note presents these measurements and compares them to other drift gases that have been simulated using GARFIELD, HEED and MAGBOLTZ.This note also describes systematic errors to be considered in the operation of precision drift chambers using such gases. In particular we analyze effects of background rate variations, gas-density changes, variations of the gas composition, autocalibration, magnetic field differences and non-concentricity of the wire. Their impact on the reconstructed muon momentum resolution was simulated with DICE/ATRECON.The different properties of linear and non-linear drift gases and their relative advantages and disadvantages are discussed in detail.

  7. Tracking chamber made of 15-mm mylar drift tubes

    Science.gov (United States)

    Kozhin, A.; Borisov, A.; Bozhko, N.; Fakhrutdinov, R.; Plotnikov, I.

    2017-05-01

    We are presenting a drift chamber composed from three layers of mylar drift tubes with outer diameter 15 mm. The pipe is made of strip of mylar film 125 micrometers thick covered with aluminium from the both sides. A strip of mylar is wrapped around the mandrel. Pipe is created by ultrasonic welding. A single drift tube is self-supported structure withstanding 350 g wire tension without supports and internal overpressure. About 400 such tubes were assembled. Design, quality control procedures of the drift tubes are described. Seven chambers were glued from these tubes of 560 mm length. Each chamber consists of 3 layers, 16 tubes per layer. Several chambers were tested with cosmic rays. Results of the tests, counting rate plateau and coordinate resolution are presented.

  8. Tracking chamber made of 15-mm mylar drift tubes

    International Nuclear Information System (INIS)

    Kozhin, A.; Borisov, A.; Bozhko, N.; Fakhrutdinov, R.; Plotnikov, I.

    2017-01-01

    We are presenting a drift chamber composed from three layers of mylar drift tubes with outer diameter 15 mm. The pipe is made of strip of mylar film 125 micrometers thick covered with aluminium from the both sides. A strip of mylar is wrapped around the mandrel. Pipe is created by ultrasonic welding. A single drift tube is self-supported structure withstanding 350 g wire tension without supports and internal overpressure. About 400 such tubes were assembled. Design, quality control procedures of the drift tubes are described. Seven chambers were glued from these tubes of 560 mm length. Each chamber consists of 3 layers, 16 tubes per layer. Several chambers were tested with cosmic rays. Results of the tests, counting rate plateau and coordinate resolution are presented.

  9. Pulse shape simulation for drift chambers with long drift paths

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, H J

    1987-09-15

    A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution.

  10. Pulse shape simulation for drift chambers with long drift paths

    International Nuclear Information System (INIS)

    Mayer, H.J.

    1987-01-01

    A detailed Monte Carlo program for the simulation of drift chamber pulse shapes is described. It has been applied to the case of a jet chamber with drift paths up to 24 cm. Results on pulse shapes and corresponding spatial and double hit resolution are discussed and compared to recent measurements of the OPAL central detector jet chamber full size prototype and to measurements of a small 20-wire prototype, which was designed to study the pulse shapes generated by tracks in a magnetic field. Simulated pulse shapes and spatial resolutions agree well with the experimental data. Clustering, saturation and wire crosstalk are shown to be necessary ingredients in the simulation. A deterioration in resolution due to the influence of crosstalk signals is correctly reproduced, as well as the cancellation of this effect by a hardwired first and second neighbour crosstalk compensation. The simulation correctly describes the asymmetry in spatial resolution observed for tracks with positive or negative inclination against the wire plane when a magnetic field is present. The effect of saturation on double hit resolution is found to be small. The magnetic field is predicted to improve the double hit resolution. (orig.)

  11. Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Taylor, F.G.; Hanna, S.R.; Parr, P.D.

    1979-01-01

    The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant

  12. Microsecond-scale X-ray imaging with Controlled-Drift Detectors

    International Nuclear Information System (INIS)

    Castoldi, A.; Galimberti, A.; Guazzoni, C.; Rehak, P.; Strueder, L.

    2006-01-01

    The Controlled-Drift Detector is a fully-depleted silicon detector that allows 2-D position sensing and energy spectroscopy of X-rays in the range 0.5-20keV with excellent time resolution (few tens of μs) and limited readout channels. In this paper we review the Controlled-Drift Detector operating principle and we present the X-ray imaging and spectroscopic capabilities of Controlled Drift Detectors in microsecond-scale experiments and the more relevant applications fields

  13. Diogene pictorial drift chamber

    International Nuclear Information System (INIS)

    Gosset, J.

    1984-01-01

    A pictorial drift chamber, called DIOGENE, has been installed at Saturne in order to study central collisions of high energy heavy ions. It has been adapted from the JADE internal detector, with two major differences to be taken into account. First, the center-of-mass of these collisions is not identical to the laboratory reference frame. Second, the energy loss and the momentum ranges of the particles to be detected are different from the ones in JADE. It was also tried to keep the cost as small as possible, hence the choice of minimum size and minimum number of sensitive wires. Moreover the wire planes are shifted from the beam axis: this trick helps very much to quickly reject the bad tracks caused by the ambiguity of measuring drift distances (positive or negative) through times (always positive)

  14. Beam Profile Disturbances from Implantable Pacemakers or Implantable Cardioverter-Defibrillator Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gossman, Michael S., E-mail: mgossman@tsrcc.com [Tri-State Regional Cancer Center, Medical Physics Section, Ashland, KY (United States); Comprehensive Heart and Vascular Associates, Heart and Vascular Center, Ashland, KY (United States); Medtronic, Inc., External Research Program, Mounds View, MN (United States); Nagra, Bipinpreet; Graves-Calhoun, Alison; Wilkinson, Jeffrey [Tri-State Regional Cancer Center, Medical Physics Section, Ashland, KY (United States); Comprehensive Heart and Vascular Associates, Heart and Vascular Center, Ashland, KY (United States); Medtronic, Inc., External Research Program, Mounds View, MN (United States)

    2011-01-01

    The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of a medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.

  15. Automated Burris gravity meter for single and continuous observation

    Directory of Open Access Journals (Sweden)

    Gerhard Jentzsch

    2018-05-01

    Full Text Available The Burris Gravity Meter™ manufactured by ZLS Corporation, Austin/Texas, USA, is based on the invention of L&R (L. LaCoste and A. Romberg: The ZLS (zero-length spring. A digital feedback system (range of about 50 mGal is used to null the beam. Now, more than 120 gravity meters of this make exist worldwide and are used successfully in exploration, volcanology, geodetic work and surveying.The sensor is made of the well-known (L&R metal-alloy zero-length spring providing a low drift characteristic. The drifts observed are comparable to L&R gravimeters and are less than 0.3 mGal per month, which is much lower than the drifts known for the fused quartz sensors.The dial is calibrated every 50 mGal over the entire 7000 mGal meter range. Since the gravity value is determined at these points, there are no periodic errors. By a fourth heater circuit temperature effects are totally avoided. The gravity meter is controlled via Bluetooth® either to a handheld computer (tablet or a notebook computer.The feedback responds with high stability and accuracy. The nulling of the beam is controlled by the UltraGrav™ control system which incorporates an inherently linear PWM (pulse-width modulated electrostatic feedback system. In order to improve the handling of the gravimeter we have developed two Windows based programs: AGESfield for single measurements and AGEScont for continuous readings. Keywords: Gravimeter, Micro-gravity measurements, Drift, Resolution, Single and continuous observations

  16. Drift waves in a weakly ionized plasma

    DEFF Research Database (Denmark)

    Popovic, M.; Melchior, H.

    1968-01-01

    A dispersion relation for low frequency drift waves in a weakly ionized plasma has been derived, and through numerical calculations the effect of collisions between the charged and the neutral particles is estimated.......A dispersion relation for low frequency drift waves in a weakly ionized plasma has been derived, and through numerical calculations the effect of collisions between the charged and the neutral particles is estimated....

  17. Charge collection in the Silicon Drift Detectors of the ALICE experiment

    CERN Document Server

    Alessandro, B; Batigne, G; Beolé, S; Biolcati, E; Cerello, P; Coli, S; Corrales Morales, Y; Crescio, E; De Remigis, P; Falchieri, D; Giraudo, G; Giubellino, P; Lea, R; Marzari Chiesa, A; Masera, M; Mazza, G; Ortona, G; Prino, F; Ramello, L; Rashevsky, A; Riccati, L; Rivetti, A; Senyukov, S; Siciliano, M; Sitta, M; Subieta, M; Toscano, L; Tosello, F

    2010-01-01

    A detailed study of charge collection efficiency has been performed on the Silicon Drift Detectors (SDD) of the ALICE experiment. Three different methods to study the collected charge as a function of the drift time have been implemented. The first approach consists in measuring the charge at different injection distances moving an infrared laser by means of micrometric step motors. The second method is based on the measurement of the charge injected by the laser at fixed drift distance and varying the drift field, thus changing the drift time. In the last method, the measurement of the charge deposited by atmospheric muons is used to study the charge collection efficiency as a function of the drift time. The three methods gave consistent results and indicated that no charge loss during the drift is observed for the sensor types used in 99% of the SDD modules mounted on the ALICE Inner Tracking System. The atmospheric muons have also been used to test the effect of the zero-suppression applied to reduce the d...

  18. Mean Lagrangian drift in continental shelf waves

    Science.gov (United States)

    Drivdal, M.; Weber, J. E. H.

    2012-04-01

    The time- and depth-averaged mean drift induced by barotropic continental shelf waves (CSW's) is studied theoretically for idealized shelf topography by calculating the mean volume fluxes to second order in wave amplitude. The waves suffer weak spatial damping due to bottom friction, which leads to radiation stress forcing of the mean fluxes. In terms of the total wave energy density E¯ over the shelf region, the radiation stress tensor component S¯11 for CSW's is found to be different from that of shallow water surface waves in a non-rotating ocean. For CSW's, the ratio ¯S11/¯E depends strongly on the wave number. The mean Lagrangian flow forced by the radiation stress can be subdivided into a Stokes drift and a mean Eulerian drift current. The magnitude of the latter depends on the ratio between the radiation stress and the bottom stress acting on the mean flow. When the effect of bottom friction acts equally strong on the waves and the mean current, calculations for short CSW's show that the Stokes drift and the friction-dependent wave-induced mean Eulerian current varies approximately in anti-phase over the shelf, and that the latter is numerically the largest. For long CSW's they are approximately in phase. In both cases the mean Lagrangian current, which is responsible for the net particle drift, has its largest numerical value at the coast on the shallow part of the shelf. Enhancing the effect of bottom friction on the Eulerian mean flow, results in a general current speed reduction, as well as a change in spatial structure for long waves. Applying realistic physical parameters for the continental shelf west of Norway, calculations yield along-shelf mean drift velocities for short CSW's that may be important for the transport of biological material, neutral tracers, and underwater plumes of dissolved oil from deep water drilling accidents.

  19. Fast non-explosive gases for drift chambers

    International Nuclear Information System (INIS)

    Green, D.; Haggerty, H.; Oshima, N.; Yamada, R.

    1988-05-01

    Typical gases which are stock at Fermilab are Ar:C 2 H 6 (50:50) and Ar:CO 2 (80:20). Argon:Ethane has the virtue of high gas gain and a saturated drift velocity. In fact, parametrizing the drift velocity as a function of electric field we find v/sub d/(E) = v/sub o/(1/minus/e/sup -E/E/o) with v/sub o/ ≅ 5.4 cm/μsec and E/sub o/ = 160 V/cm. However, safety considerations make this gas somewhat inconvenient. The addition of alcohol as quencher also raises the saturation field to, for example, E/sub o/ ≅ 500 V/cm for 1.5% added alcohol. This gas also tends to break up in a high-beam flux environment and leave carbon deposits. The addition of alcohol to avoid such aging often takes a unit cell out of saturation over its entire volume. Finally, for collider applications it is useful to exclude free protons from the gas in order to reduce the sensitivity to the sea of slow neutrons which are present in the collider environment. In contrast, Ar:CO 2 (80:20) is a gas with more moderate gas gain. The drift velocity at high field is v/sub d/(E > 1.5 kV/cm) ≅ 5.8 cm/μsec. For most field configurations this gas does not saturate, causing a long tail in the drift time distrubtion due to low field regions in the unit cell. The virtues of this gas mixture are that it is cheap, not flammable, and stable under high-beam flux. However as the Collider Upgrade progresses, we wish to find a gas which is faster than 5.0 cm/μsec since the time separation between collisions will at some point be less than drift time of 1μsec for drift distance of 5 cm. 3 refs., 5 figs

  20. Unsteady force estimation using a Lagrangian drift-volume approach

    Science.gov (United States)

    McPhaden, Cameron J.; Rival, David E.

    2018-04-01

    A novel Lagrangian force estimation technique for unsteady fluid flows has been developed, using the concept of a Darwinian drift volume to measure unsteady forces on accelerating bodies. The construct of added mass in viscous flows, calculated from a series of drift volumes, is used to calculate the reaction force on an accelerating circular flat plate, containing highly-separated, vortical flow. The net displacement of fluid contained within the drift volumes is, through Darwin's drift-volume added-mass proposition, equal to the added mass of the plate and provides the reaction force of the fluid on the body. The resultant unsteady force estimates from the proposed technique are shown to align with the measured drag force associated with a rapid acceleration. The critical aspects of understanding unsteady flows, relating to peak and time-resolved forces, often lie within the acceleration phase of the motions, which are well-captured by the drift-volume approach. Therefore, this Lagrangian added-mass estimation technique opens the door to fluid-dynamic analyses in areas that, until now, were inaccessible by conventional means.

  1. The Study of Westward Drift in the Main Geomagnetic Field

    Directory of Open Access Journals (Sweden)

    G. Bayanjargal

    2013-01-01

    Full Text Available We have obtained a solution for the velocity of westward drift from the induction equation in which an approach for main geomagnetic field was built. Distribution functions B(r, t entered into the induction equation have been built by the observatories' data in North America and the Europe from 1991 to 2006. The longitudinal −0.123 degree/year and latitudinal 0.068 degree/year drifts were defined in North America. And the longitudinal −0.257 degree/year drift was defined in Europe from 1991 to 2006. These drifts are similar to results of other studies.

  2. Simulation of peri-implant bone healing due to immediate loading in dental implant treatments.

    Science.gov (United States)

    Chou, Hsuan-Yu; Müftü, Sinan

    2013-03-15

    The goal of this work was to investigate the role of immediate loading on the peri-implant bone healing in dental implant treatments. A mechano-regulatory tissue differentiation model that takes into account the stimuli through the solid and the fluid components of the healing tissue, and the diffusion of pluripotent stem cells into the healing callus was used. A two-dimensional axisymmetric model consisting of a dental implant, the healing callus tissue and the host bone tissue was constructed for the finite element analysis. Poroelastic material properties were assigned to the healing callus and the bone tissue. The effects of micro-motion, healing callus size, and implant thread design on the length of the bone-to-implant contact (BIC) and the bone volume (BV) formed in the healing callus were investigated. In general, the analysis predicted formation of a continuous layer of soft tissue along the faces of the implant which are parallel to the loading direction. This was predicted to be correlated with the high levels of distortional strain transferred through the solid component of the stimulus. It was also predicted that the external threads on the implant, redistribute the interfacial load, thus help reduce the high distortional stimulus and also help the cells to differentiate to bone tissue. In addition, the region underneath the implant apex was predicted to experience high fluid stimulus that results in the development of soft tissue. The relationship between the variables considered in this study and the outcome measures, BV and BIC, was found to be highly nonlinear. A three-way analysis of variance (ANOVA) of the results was conducted and it showed that micro-motion presents the largest hindrance to bone formation during healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. A simple method to produce quasi-simultaneous multiple energy helium implantation

    International Nuclear Information System (INIS)

    Paszti, F.; Fried, M.; Manuaba, A.; Mezey, G.; Kotai, E.; Lohner, T.

    1982-11-01

    If a monoenergetic ion beam is bombarding a target through an absorber foil tilted continuously (i.e. its effective thickness changing continuously), the depth distribution of the implanted ions in the sample depends on the way the absorber is moving. The present paper describes a way of absorber tilting for obtaining a uniform depth distribution and its experimental verification in the case of MeV energy helium ions implanted into aluminium target. (author)

  4. Approximate Stokes Drift Profiles in Deep Water

    Science.gov (United States)

    Breivik, Øyvind; Janssen, Peter A. E. M.; Bidlot, Jean-Raymond

    2014-09-01

    A deep-water approximation to the Stokes drift velocity profile is explored as an alternative to the monochromatic profile. The alternative profile investigated relies on the same two quantities required for the monochromatic profile, viz the Stokes transport and the surface Stokes drift velocity. Comparisons with parametric spectra and profiles under wave spectra from the ERA-Interim reanalysis and buoy observations reveal much better agreement than the monochromatic profile even for complex sea states. That the profile gives a closer match and a more correct shear has implications for ocean circulation models since the Coriolis-Stokes force depends on the magnitude and direction of the Stokes drift profile and Langmuir turbulence parameterizations depend sensitively on the shear of the profile. The alternative profile comes at no added numerical cost compared to the monochromatic profile.

  5. Nonlinear propagation of short wavelength drift-Alfven waves

    DEFF Research Database (Denmark)

    Shukla, P. K.; Pecseli, H. L.; Juul Rasmussen, Jens

    1986-01-01

    Making use of a kinetic ion and a hydrodynamic electron description together with the Maxwell equation, the authors derive a set of nonlinear equations which governs the dynamics of short wavelength ion drift-Alfven waves. It is shown that the nonlinear drift-Alfven waves can propagate as two-dim...

  6. Amplifying the helicopter drift in a conformal HMD

    Science.gov (United States)

    Schmerwitz, Sven; Knabl, Patrizia M.; Lueken, Thomas; Doehler, Hans-Ullrich

    2016-05-01

    Helicopter operations require a well-controlled and minimal lateral drift shortly before ground contact. Any lateral speed exceeding this small threshold can cause a dangerous momentum around the roll axis, which may cause a total roll over of the helicopter. As long as pilots can observe visual cues from the ground, they are able to easily control the helicopter drift. But whenever natural vision is reduced or even obscured, e.g. due to night, fog, or dust, this controllability diminishes. Therefore helicopter operators could benefit from some type of "drift indication" that mitigates the influence of a degraded visual environment. Generally humans derive ego motion by the perceived environmental object flow. The visual cues perceived are located close to the helicopter, therefore even small movements can be recognized. This fact was used to investigate a modified drift indication. To enhance the perception of ego motion in a conformal HMD symbol set the measured movement was used to generate a pattern motion in the forward field of view close or on the landing pad. The paper will discuss the method of amplified ego motion drift indication. Aspects concerning impact factors like visualization type, location, gain and more will be addressed. Further conclusions from previous studies, a high fidelity experiment and a part task experiment, will be provided. A part task study will be presented that compared different amplified drift indications against a predictor. 24 participants, 15 holding a fixed wing license and 4 helicopter pilots, had to perform a dual task on a virtual reality headset. A simplified control model was used to steer a "helicopter" down to a landing pad while acknowledging randomly placed characters.

  7. Properties of low-pressure drift chambers

    International Nuclear Information System (INIS)

    Breskin, A.; Trautner, N.

    1976-01-01

    Drift chambers operated with methylal vapour or ethylene at pressures in the range of 10-110 torr are described. A systematic study of position resolution, pulse height and rise time shows that especially for ethylene they are strongly influenced by electron diffusion. Intrinsic position resolution was found to be at least as good as found at atmospheric pressure. A relative pulse height resolution of 10% was obtained with 5.5 MeV alpha-particles. A simple mathematical model which can describe the processes in the drift chamber is presented. (Auth.)

  8. Search for the best timing strategy in high-precision drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1983-06-01

    Computer simulated drift chamber pulses are used to investigate various possible timing strategies in the drift chambers. In particular, the leading edge, the multiple threshold and the flash ADC timing methods are compared. Although the presented method is general for any drift geometry, we concentrate our discussion on the jet chambers where the drift velocity is about 3 to 5 cm/μsec and the individual ionization clusters are not resolved due to a finite speed of our electronics

  9. Viscose kink and drift-kink modes in a tokamak

    International Nuclear Information System (INIS)

    Kuvshinov, B.N.; Mikhajlovskij, A.B.

    1988-01-01

    Intristic kink modes in a tokamak are theoretically investigated taking account of longitudinal viscosity of ions and electrons and drift effect. It is marked that dispersion equation of investigated modes coinsides in form with that for ballooning modes. It is shown that five types of intrinsic kink instability may be distinguished in disregard of viscosity and drift effects. Effect of stabilizing quasiideal viscose kink and viscose resistive kink modes by finite Larmuir ion radius is investigated. A branch of viscose reclosure mode which instability is due to electron viscosity is pointed out. A series of other viscose and drift-kink tokamak modes is considered. Both general disperse equations of the above-mentioned kink instability varieties, taking account of viscose and drift ones, and disperse equations of separate branches are presented

  10. Exploiting Rating Abstention Intervals for Addressing Concept Drift in Social Network Recommender Systems

    Directory of Open Access Journals (Sweden)

    Dionisis Margaris

    2018-04-01

    Full Text Available One of the major problems that social networks face is the continuous production of successful, user-targeted information in the form of recommendations, which are produced exploiting technology from the field of recommender systems. Recommender systems are based on information about users’ past behavior to formulate recommendations about their future actions. However, as time goes by, social network users may change preferences and likings: they may like different types of clothes, listen to different singers or even different genres of music and so on. This phenomenon has been termed as concept drift. In this paper: (1 we establish that when a social network user abstains from rating submission for a long time, it is a strong indication that concept drift has occurred and (2 we present a technique that exploits the abstention interval concept, to drop from the database ratings that do not reflect the current social network user’s interests, thus improving prediction quality.

  11. A drift free nernstian iridium oxide PH sensor

    NARCIS (Netherlands)

    Hendrikse, J.; Olthuis, Wouter; Bergveld, Piet

    1997-01-01

    A novel way of eliminating drift problems in metal oxide pH sensors is presented. The method employs a FET-structure under the electrode that uses the metal oxide as a gate contact. In addition to the enhanced drift properties, the new sensor has an almost ideal nernstian response. First a

  12. Simultaneous recordings of human microsaccades and drifts with a contemporary video eye tracker and the search coil technique.

    Directory of Open Access Journals (Sweden)

    Michael B McCamy

    Full Text Available Human eyes move continuously, even during visual fixation. These "fixational eye movements" (FEMs include microsaccades, intersaccadic drift and oculomotor tremor. Research in human FEMs has grown considerably in the last decade, facilitated by the manufacture of noninvasive, high-resolution/speed video-oculography eye trackers. Due to the small magnitude of FEMs, obtaining reliable data can be challenging, however, and depends critically on the sensitivity and precision of the eye tracking system. Yet, no study has conducted an in-depth comparison of human FEM recordings obtained with the search coil (considered the gold standard for measuring microsaccades and drift and with contemporary, state-of-the art video trackers. Here we measured human microsaccades and drift simultaneously with the search coil and a popular state-of-the-art video tracker. We found that 95% of microsaccades detected with the search coil were also detected with the video tracker, and 95% of microsaccades detected with video tracking were also detected with the search coil, indicating substantial agreement between the two systems. Peak/mean velocities and main sequence slopes of microsaccades detected with video tracking were significantly higher than those of the same microsaccades detected with the search coil, however. Ocular drift was significantly correlated between the two systems, but drift speeds were higher with video tracking than with the search coil. Overall, our combined results suggest that contemporary video tracking now approaches the search coil for measuring FEMs.

  13. Abstraction of Drift-Scale Coupled Processes

    International Nuclear Information System (INIS)

    Francis, N.D.; Sassani, D.

    2000-01-01

    This Analysis/Model Report (AMR) describes an abstraction, for the performance assessment total system model, of the near-field host rock water chemistry and gas-phase composition. It also provides an abstracted process model analysis of potentially important differences in the thermal hydrologic (TH) variables used to describe the performance of a geologic repository obtained from models that include fully coupled reactive transport with thermal hydrology and those that include thermal hydrology alone. Specifically, the motivation of the process-level model comparison between fully coupled thermal-hydrologic-chemical (THC) and thermal-hydrologic-only (TH-only) is to provide the necessary justification as to why the in-drift thermodynamic environment and the near-field host rock percolation flux, the essential TH variables used to describe the performance of a geologic repository, can be obtained using a TH-only model and applied directly into a TSPA abstraction without recourse to a fully coupled reactive transport model. Abstraction as used in the context of this AMR refers to an extraction of essential data or information from the process-level model. The abstraction analysis reproduces and bounds the results of the underlying detailed process-level model. The primary purpose of this AMR is to abstract the results of the fully-coupled, THC model (CRWMS M andO 2000a) for effects on water and gas-phase composition adjacent to the drift wall (in the near-field host rock). It is assumed that drift wall fracture water and gas compositions may enter the emplacement drift before, during, and after the heating period. The heating period includes both the preclosure, in which the repository drifts are ventilated, and the postclosure periods, with backfill and drip shield emplacement at the time of repository closure. Although the preclosure period (50 years) is included in the process models, the postclosure performance assessment starts at the end of this initial period

  14. Drift-free MPEG-4 AVC semi-fragile watermarking

    Science.gov (United States)

    Hasnaoui, M.; Mitrea, M.

    2014-02-01

    While intra frame drifting is a concern for all types of MPEG-4 AVC compressed-domain video processing applications, it has a particular negative impact in watermarking. In order to avoid the drift drawbacks, two classes of solutions are currently considered in the literature. They try either to compensate the drift distortions at the expense of complex decoding/estimation algorithms or to restrict the insertion to the blocks which are not involved in the prediction, thus reducing the data payload. The present study follows a different approach. First, it algebraically models the drift distortion spread problem by considering the analytic expressions of the MPEG-4 AVC encoding operations. Secondly, it solves the underlying algebraic system under drift-free constraints. Finally, the advanced solution is adapted to take into account the watermarking peculiarities. The experiments consider an m-QIM semi-fragile watermarking method and a video surveillance corpus of 80 minutes. For prescribed data payload (100 bit/s), robustness (BER < 0.1 against transcoding at 50% in stream size), fragility (frame modification detection with accuracies of 1/81 from the frame size and 3s) and complexity constraints, the modified insertion results in gains in transparency of 2 dB in PSNR, of 0.4 in AAD, of 0.002 in IF, of 0.03 in SC, of 0.017 NCC and 22 in DVQ.

  15. Short Implants: New Horizon in Implant Dentistry.

    Science.gov (United States)

    Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-09-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

  16. Gigantic uphill drift of vacancies and self-interstitials in silicon

    International Nuclear Information System (INIS)

    Voronkov, V.V.; Falster, R.

    2009-01-01

    Point defect transport in a growing crystal includes a drift along the temperature gradient, G, at a velocity αG. It was not clear if the drift is negligible or strong in silicon crystal growth. It is now found that reported microdefect patterns in crystals grown with a temporarily halt provide a clear evidence in favour of a strong (even gigantic) drift of both kinds of intrinsic point defects. The drift coefficients α V (for vacancies) and α I (for self-interstitials) are deduced by fitting the simulating defect profiles to the observed location of halt-induced interstitial region immersed into a vacancy-type crystal.

  17. Effect of magnetic shear on dissipative drift instabilities

    International Nuclear Information System (INIS)

    Guzdar, P.N.; Chen, L.; Kaw, P.K.; Oberman, C.

    1978-03-01

    In this letter we report the results of a linear radial eigenmode analysis of dissipative drift waves in a plasma with magnetic shear and spatially varying density gradient. The results of the analysis are shown to be consistent with a recent experiment on the study of dissipative drift instabilities in a toroidal stellarator

  18. Influence of Palatal Coverage and Implant Distribution on Implant Strain in Maxillary Implant Overdentures.

    Science.gov (United States)

    Takahashi, Toshihito; Gonda, Tomoya; Mizuno, Yoko; Fujinami, Yozo; Maeda, Yoshinobu

    2016-01-01

    Maxillary implant overdentures are often used in clinical practice. However, there is no agreement or established guidelines regarding prosthetic design or optimal implant placement configuration. The purpose of this study was to examine the influence of palatal coverage and implant number and distribution in relation to impact strain under maxillary implant overdentures. A maxillary edentulous model with implants and experimental overdentures with and without palatal coverage was fabricated. Four strain gauges were attached to each implant, and they were positioned in the anterior, premolar, and molar areas. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the implant strains were compared using one-way analysis of variance (P = .05). The palatolabial strain was much higher on anterior implants than on other implants in both denture types. Although there was no significant difference between the strain under dentures with and without palatal coverage, palateless dentures tended to result in higher implant strain than dentures with palatal coverage. Dentures supported by only two implants registered higher strain than those supported by four or six implants. Implants under palateless dentures registered higher strain than those under dentures with palatal coverage. Anterior implants exhibited higher palatolabial strain than other implants regardless of palatal coverage and implant configuration; it is therefore recommended that maxillary implant overdentures should be supported by six implants with support extending to the distal end of the arch.

  19. Short Dental Implants Retaining Two-Implant Mandibular Overdentures in Very Old, Dependent Patients: Radiologic and Clinical Observation Up to 5 Years.

    Science.gov (United States)

    Maniewicz, Sabrina; Buser, Ramona; Duvernay, Elena; Vazquez, Lydia; Loup, Angelica; Perneger, Thomas V; Schimmel, Martin; Müller, Frauke

    To describe the survival rate and peri-implant bone loss in very old patients dependent for their activities of daily living (ADL), treated with mandibular two-implant overdentures (IODs) in the context of a previously reported randomized controlled trial. A total of 19 patients received two interforaminal Straumann implants (Regular Neck, 4.1 mm diameter, 8 mm length) that were subsequently loaded with Locator attachments, transforming their preexisting inferior conventional denture into an IOD. The primary outcome measures were implant survival rate and radiographically assessed peri-implant bone loss. Secondary outcome measures included peri-implant probing depth and Plaque Index scores, as well as implant mobility. Nutritional state (body mass index and blood markers) and cognitive state (Mini-Mental State Examination) were also analyzed. The patient cohort comprised eight men and 11 women with a mean age of 85.7 ± 6.6 years. The implant survival rate up to 5 years was 94.7%, with one early and one late implant failure. The mean loss of peri-implant bone height was 0.17 mm per year (95% confidence interval: 0.09 to 0.24; P implant probing depth and Plaque Index scores were low and stable during the first 2 years, and thereafter increased continuously. Correlation analysis suggests that a reduced cognitive function and nutritional state are not a particular risk factor for accelerated peri-implant bone loss. The high implant survival and acceptable peri-implant health suggest that neither age nor dependency for the ADLs is a contraindication for the placement of implants. Nevertheless, close monitoring of the patients concerning a potential further functional decline precluding denture management and performing oral hygiene measures is advised.

  20. Drift orbits in the TMX and MFTF-B tandem mirrors

    International Nuclear Information System (INIS)

    Byers, J.A.

    1982-01-01

    Drift orbits for the TMX and MFTF-B tandem-mirror designs are followed by using a long-thin expansion of the drift equations. Unexpected asymmetries in the field-line curvatures in the yin-yang end-mirror traps, caused by the transition coils between the solenoid and the yin-yang, result in an elliptical distortion of the drift surface with a/b=1.5 at most, a perhaps tolerable deviation from omnigenity. Yushmanov-trapped particles are no worse than the bulk hot particles. Finite-beta plasma fields, coupled to the asymmetric curvature, produce sizeable banana orbits with widths comparable to the plasma radius, but these orbits are possible for only a few of the particles. Details of the transition through resonance in the solenoid are shown, including the banana shapes of the drift surfaces and the disruption of the surface in the stochastic regime. The orbits in the original design for the A-cell of MFTF-B are the most extreme; in the vacuum fields they all have an extended peanut shape that finally closes only at about 3m. This shape is strongly non-omnigenous and suggests a hollow plasma-density profile. Finite-beta B vectorxnablaB drifts can help to minimize the radial extent of these orbits, but the strength of the vacuum curvatures makes omnigenity only marginally possible. Including B vectorxnablaphi drifts makes omnigenity even more unlikely for the ions, for which the B vectorxnablaB and B vectorxnablaphi drifts are of opposite sign, and conversely helps to omnigenize the drift surfaces of the ECRH 200-keV electrons. It is argued that not every class of particles can have good, i.e. near-omnigenous drifts, regardless of the ability of phi(r) to adjust to limit the radial extent of the orbits. This lack of omnigenity leaves one with no theoretical base for describing the MHD equilibrium in the original designs, but a new magnetic field design for MFTF-B A-cell has apparently completely restored omnigenous orbits. (author)

  1. Silicon drift-chamber studies for possible use at RHIC

    International Nuclear Information System (INIS)

    Humanic, T.J.

    1990-01-01

    It is proposed to continue the program now underway at the University of Pittsburgh to study the feasibility of using silicon drift-chambers as particle tracking devices at RHIC. We are currently testing a UA6-type detector obtained from BNL, and propose to also study a new device that will become available this year: a cylindrical geometry detector design for NA45 (CERN). This new detector will be produced at BNL and the MPI-Institute in Munich and will incorporate updated techniques which should result in a reliable device with improved performance over the UA6-type detector. The one-year budget for this proposal is $50,079. 28 refs., 2 figs

  2. Longevity of Emplacement Drift Ground Support Materials, Rev. 01

    International Nuclear Information System (INIS)

    David H. Tang

    2000-01-01

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for the selection of materials for ground support that will function throughout the preclosure period of a potential repository at Yucca Mountain. The Development Plan (DP) for this analysis is given in Longevity of Emplacement Drift Ground Support Materials (CRWMS M and O 1999a). The objective of this analysis is to update the previous analysis (CRWMS M and O 2000a) to account for related changes in the Ground Control System Description Document (CRWMS M and O 2000b), the Monitored Geologic Repository Project Description Document (CRWMS M and O 1999b), and in environmental conditions, and to provide updated information on candidate ground support materials. Candidate materials for ground support are carbon steel and cement grout. Steel is mainly used for steel sets, lagging, channel, rock bolts, and wire mesh. Cement grout is only considered in the case of grouted rock bolts. Candidate materials for the emplacement drift invert are carbon steel and crushed rock ballast. Materials are evaluated for the repository emplacement drift environment based on the updated thermal loading condition and waste package design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground support materials for use in emplacement drifts; (2) Review existing documents concerning the behavior of candidate ground support materials during the preclosure period; (3) Evaluate impacts of temperature and radiation effects on mechanical and thermal properties of steel. Assess corrosion potential of steel at emplacement drift environment; (4) Evaluate factors affecting longevity of cement grouts for fully grouted rock bolt system. Provide updated information on cement grout mix design for fully grouted rock bolt system; and (5) Evaluate longevity of materials for the emplacement drift invert

  3. Barber's Point, Oahu, Hawaii Drift Card Study 2002-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Drift cards were be released from Barber's Point, Oahu, approximately once a month during the two year span to get an idea of the distribution of card drift under...

  4. Principle and applications of Controlled-Drift Detectors

    International Nuclear Information System (INIS)

    Castoldi, A.; Guazzoni, C.; Hartmann, R.; Strueder, L.

    2007-01-01

    The Controlled-Drift Detector is a fully depleted silicon detector that allows 2D position sensing and energy spectroscopy of X-rays in the range 0.5-30 keV with imaging capability up to 100 kframe/s, event timing of few ns and limited readout channels. In this paper we review the Controlled-Drift Detector operating principle and we present its applications in X-ray absorption imaging and in Compton electrons tracking

  5. The development of magnetic field measurement system for drift-tube linac quadrupole

    Science.gov (United States)

    Zhou, Jianxin; Kang, Wen; Yin, Baogui; Peng, Quanling; Li, Li; Liu, Huachang; Gong, Keyun; Li, Bo; Chen, Qiang; Li, Shuai; Liu, Yiqin

    2015-06-01

    In the China Spallation Neutron Source (CSNS) linac, a conventional 324 MHz drift-tube linac (DTL) accelerating an H- ion beam from 3 MeV to 80 MeV has been designed and manufactured. The electromagnetic quadrupoles (EMQs) are widely used in a DTL accelerator. The main challenge of DTLQ's structure is to house a strong gradient EMQ in the much reduced space of the drift-tube (DT). To verify the DTLQ's design specifications and fabrication quality, a precision harmonic coil measurement system has been developed, which is based on the high precision movement platform, the harmonic coil with ceramic frame and the special method to make the harmonic coil and the quadrupoles coaxial. After more than one year's continuous running, the magnetic field measurement system still performs accurately and stably. The field measurement of more than one hundred DTLQ has been finished. The components and function of the measurement system, the key point of the technology and the repeatability of the measurement results are described in this paper.

  6. Analysis of the SPS Long Term Orbit Drifts

    Energy Technology Data Exchange (ETDEWEB)

    Velotti, Francesco [CERN; Bracco, Chiara [CERN; Cornelis, Karel [CERN; Drøsdal, Lene [CERN; Fraser, Matthew [CERN; Gianfelice-Wendt, Eliana [Fermilab; Goddard, Brennan [CERN; Kain, Verena [CERN; Meddahi, Malika [CERN

    2016-06-01

    The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain, and has to deliver the two high-intensity 450 GeV proton beams to the LHC. The transport from SPS to LHC is done through the two Transfer Lines (TL), TI2 and TI8, for Beam 1 (B1) and Beam 2 (B2) respectively. During the first LHC operation period Run 1, a long term drift of the SPS orbit was observed, causing changes in the LHC injection due to the resulting changes in the TL trajectories. This translated into longer LHC turnaround because of the necessity to periodically correct the TL trajectories in order to preserve the beam quality at injection into the LHC. Different sources for the SPS orbit drifts have been investigated: each of them can account only partially for the total orbit drift observed. In this paper, the possible sources of such drift are described, together with the simulated and measured effect they cause. Possible solutions and countermeasures are also discussed.

  7. Position reconstruction in drift chambers operated with Xe, $CO_{2}$ (15\\%)

    CERN Document Server

    Adler, C; Appelshäuser, H; Bielcikova, J; Blume, C; Braun-Munzinger, P; Bucher, D; Busch, O; Catanescu, V; Ciobanu, M; Daues, H W; Emschermann, D; Fateev, O V; Foka, P; Garabatos, C; Gunji, T; Herrmann, N; Inuzuka, M; Ivanov, M; Kislov, E; Lindenstruth, V; Lippmann, C; Ludolphs, W; Mahmoud, T; Petracek, V; Petrovici, M; Radomski, S; Rusanov, I; Sandoval, A; Santo, R; Schicker, R; Schwarz, K; Simon, R S; Smykov, L P; Soltveit, H K; Stachel, J; Stelzer, H; Tsiledakis, G; Vulpescu, B; Wessels, J P; Windelband, B; Yurevich, V; Zanevsky, Yu; Zaudtke, O

    2005-01-01

    We present measurements of position and angular resolution of drift chambers operated with a Xe, CO2 (15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects - in particular the dispersive nature of the absorption of transition radiation and non-linearities - are discussed. The measurements were carried out with prototype drift chambers of the ALICE Transition Radiation Detector, but our findings can be generalized to other drift chambers with similar geometry, where the electron drift is perpendicular to the wire planes.

  8. Drift motions of small-scale irregularities in the high-latitude F region: An experimental comparison with plasma drift motions

    International Nuclear Information System (INIS)

    Ruohoniemi, J.M.; Greenwald, R.A.; Baker, K.B.; Villain, J.P.; McCready, M.A.

    1987-01-01

    On the evening of January 6, 1986, coordinated observations were carried out with the Johns Hopkins University Applied Physics Laboratory HF coherent scatter radar at Goose Bay, Labrador, and the SRI International incoherent scatter radar at Sondre Stromfjord, Greenland. The common field of view comprised a section of high-latitude F region ionosphere centered on the great circle plane between the radar sites. Over a 40-min period, the HF radar observed strong backscatter from small-scale (13.9 m) field-aligned irregularities. The bulk line-of-sight drift velocity of the irregularities is deduced from the backscatter data. The returns collected simultaneously with the incoherent scatter radar are processed for estimates of the mean line-of-sight ion velocity. Approximately 100 distinct comparisons are possible between the two sets of velocity estimates. Reversals exceeding 1,000 m/s are present in both. In this paper, the authors demonstrate a correspondence between the measured irregularity and ion drifts that is consistent with the supposition that the motion of the irregularities is dominated by convective drift of the ambient plasma. This indicates that the small-scale irregularities detected by HF radars in the high-latitude F region can serve as tracers of ionospheric convective drift

  9. SEEPAGE INTO DRIFTS IN UNSATRUATED FRACTURED ROCK AT YUCCA MOUNTAIN

    International Nuclear Information System (INIS)

    JENS BIRHOLZER; GUOMIN LI; CHIN-FU TSANG; YVONNE TSANG

    1998-01-01

    An important issue for the long-term performance of underground nuclear waste repositories is the rate of seepage into the waste emplacement drifts. A prediction of the future seepage rate is particularly complicated for the potential repository site at Yucca Mountain, Nevada, as it is located in thick, partially saturated, fractured tuff formations. The long-term situation in the drifts several thousand years after waste emplacement will be characterized by a relative humidity level close to or equal to 100%. as the drifts will be sealed and unventilated, and the waste packages will have cooled. The underground tunnels will then act as capillary barriers for the unsaturated flow, ideally diverting water around them, if the capillary forces are stronger than gravity and viscous forces. Seepage into the drifts will only be possible if the hydraulic pressure in the rock close to the drift walls increases to positive values; i.e., the flow field becomes locally saturated. In the present work, we have developed and applied a methodology to study the potential rate of seepage into underground cavities embedded in a variably saturated, heterogeneous fractured rock formation. The fractured rock mass is represented as a stochastic continuum where the fracture permeabilities vary by several orders of magnitude. Three different realizations of random fracture permeability fields are generated, with the random permeability structure based on extensive fracture mapping, borehole video analysis, and in-situ air permeability testing. A 3-D numerical model is used to simulate the heterogeneous steady-state flow field around the drift, with the drift geometry explicitly represented within the numerical discretization grid. A variety of flow scenarios are considered assuming present-day and future climate conditions at Yucca Mountain. The numerical study is complemented by theoretical evaluations of the drift seepage problem, using stochastic perturbation theory to develop a better

  10. A chopper-stabilized long pulse integrator with low drift

    International Nuclear Information System (INIS)

    Wei Yongqing; Xie Jikang; Wan Baonian; Shen Biao

    2006-01-01

    A chopper-stabilized integrator for tokamak with a digital signal processing unit to dynamically suppress the primary drift factors of analog integrator, has been designed. Long pulse integrations with low drift have been obtained with this apparatus in experiments. (authors)

  11. Beam test of a large area silicon drift detector

    International Nuclear Information System (INIS)

    Castoldi, A.; Chinnici, S.; Gatti, E.; Longoni, A.; Palma, F.; Sampietro, M.; Rehak, P.; Ballocchi, G.; Kemmer, J.; Holl, P.; Cox, P.T.; Giacomelli, P.; Vacchi, A.

    1992-01-01

    The results from the tests of the first large area (4 x 4 cm 2 ) planar silicon drift detector prototype in a pion beam are reported. The measured position resolution in the drift direction is (σ=40 ± 10)μm

  12. The Effects of Radial and Poloidal ExB Drifts in the Tokamak SOL

    International Nuclear Information System (INIS)

    Ou Jing; Zhu Sizheng

    2006-01-01

    The effects of radial and poloidal ExB drifts in the scrape-off layer (SOL) of a limiter tokamak are studied with a one-dimensional fluid code. The transport equations are solved in the poloidal direction with the radial influxes as the source terms. The simulation results show that in the high recycling regime, the effect of the radial ExB drift on plasma density tends to be stronger than that of the poloidal ExB drift. In the sheath-limited regime, the effects of the radial ExB drift and poloidal ExB drift on plasma density are almost equally important. Considering the influence on the electron temperature, the poloidal ExB drift tends to be more important than the radial ExB drift in both the high recycling regime and sheath-limited regime. For the normal B φ , the poloidal ExB drift tends to raise the pressure at the low field side while the radial ExB drift favours the high field side. The simulation results also show that the ExB drift influences the asymmetries on the parameter distributions at the high field side and low field side, and the distributions are much more symmetric with the field reversal

  13. Ionospheric drift measurements: Skymap points selection

    Czech Academy of Sciences Publication Activity Database

    Kouba, Daniel; Boška, Josef; Galkin, I. A.; Santolík, Ondřej; Šauli, Petra

    2008-01-01

    Roč. 43, č. 1 (2008), RS1S90/1-RS1S90/11 ISSN 0048-6604 R&D Projects: GA ČR GA205/06/1619; GA ČR GA205/06/1267; GA AV ČR IAA300420504 Grant - others:GA MŠk(CZ) OC 296; MIERS(XE) COST 296 Institutional research plan: CEZ:AV0Z30420517 Keywords : digisonde drift measurement * plasma drift * radio sounding * ionosphere * Doppler shift * skymap processing Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.092, year: 2008 http://www.agu.org/pubs/crossref/2008/2007RS003633.shtml

  14. Longevity of Emplacement Drift Ground Support Materials

    International Nuclear Information System (INIS)

    D.H.Tang

    2001-01-01

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for the selection of materials for ground support that will function throughout the preclosure period of a potential repository at Yucca Mountain. REV 01 ICN 01 of this analysis is developed in accordance with AP-3.10Q, Analyses and Models, Revision 2, ICN 4, and prepared in accordance with the Technical Work Plan for Subsurface Design Section FY 01 Work Activities (CRWMS M and O 2001a). The objective of this analysis is to update the previous analysis (CRWMS M and O 2000a) to account for related changes in the Ground Control System Description Document (CRWMS M and O 2000b), the Monitored Geologic Repository Project Description Document, which is included in the Requirements and Criteria for Implementing a Repository Design that can be Operated Over a Range of Thermal Modes (BSC 2001), input information, and in environmental conditions, and to provide updated information on candidate ground support materials. Candidate materials for ground support are carbon steel and cement grout. Steel is mainly used for steel sets, lagging, channel, rock bolts, and wire mesh. Cement grout is only considered in the case of grouted rock bolts. Candidate materials for the emplacement drift invert are carbon steel and granular natural material. Materials are evaluated for the repository emplacement drift environment based on the updated thermal loading condition and waste package design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground support materials for use in emplacement drifts. (2) Review existing documents concerning the behavior of candidate ground support materials during the preclosure period. (3) Evaluate impacts of temperature and radiation effects on mechanical and thermal properties of steel. Assess corrosion potential of steel at emplacement drift environment. (4

  15. Tapping with intentional drift

    NARCIS (Netherlands)

    Vardy, A.N.; Daffertshofer, A.; Beek, P.J.

    2009-01-01

    When tapping a desired frequency, subjects tend to drift away from this target frequency. This compromises the estimate of the correlation between inter-tap intervals (ITIs) as predicted by the two-level model of Wing and Kristofferson which consists of an internal timer ('clock') and motor delays.

  16. Semiconductor Ion Implanters

    International Nuclear Information System (INIS)

    MacKinnon, Barry A.; Ruffell, John P.

    2011-01-01

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion! Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  17. Measurement of Spray Drift with a Specifically Designed Lidar System.

    Science.gov (United States)

    Gregorio, Eduard; Torrent, Xavier; Planas de Martí, Santiago; Solanelles, Francesc; Sanz, Ricardo; Rocadenbosch, Francesc; Masip, Joan; Ribes-Dasi, Manel; Rosell-Polo, Joan R

    2016-04-08

    Field measurements of spray drift are usually carried out by passive collectors and tracers. However, these methods are labour- and time-intensive and only provide point- and time-integrated measurements. Unlike these methods, the light detection and ranging (lidar) technique allows real-time measurements, obtaining information with temporal and spatial resolution. Recently, the authors have developed the first eye-safe lidar system specifically designed for spray drift monitoring. This prototype is based on a 1534 nm erbium-doped glass laser and an 80 mm diameter telescope, has scanning capability, and is easily transportable. This paper presents the results of the first experimental campaign carried out with this instrument. High coefficients of determination (R² > 0.85) were observed by comparing lidar measurements of the spray drift with those obtained by horizontal collectors. Furthermore, the lidar system allowed an assessment of the drift reduction potential (DRP) when comparing low-drift nozzles with standard ones, resulting in a DRP of 57% (preliminary result) for the tested nozzles. The lidar system was also used for monitoring the evolution of the spray flux over the canopy and to generate 2-D images of these plumes. The developed instrument is an advantageous alternative to passive collectors and opens the possibility of new methods for field measurement of spray drift.

  18. Incremental learning of concept drift in nonstationary environments.

    Science.gov (United States)

    Elwell, Ryan; Polikar, Robi

    2011-10-01

    We introduce an ensemble of classifiers-based approach for incremental learning of concept drift, characterized by nonstationary environments (NSEs), where the underlying data distributions change over time. The proposed algorithm, named Learn(++). NSE, learns from consecutive batches of data without making any assumptions on the nature or rate of drift; it can learn from such environments that experience constant or variable rate of drift, addition or deletion of concept classes, as well as cyclical drift. The algorithm learns incrementally, as other members of the Learn(++) family of algorithms, that is, without requiring access to previously seen data. Learn(++). NSE trains one new classifier for each batch of data it receives, and combines these classifiers using a dynamically weighted majority voting. The novelty of the approach is in determining the voting weights, based on each classifier's time-adjusted accuracy on current and past environments. This approach allows the algorithm to recognize, and act accordingly, to the changes in underlying data distributions, as well as to a possible reoccurrence of an earlier distribution. We evaluate the algorithm on several synthetic datasets designed to simulate a variety of nonstationary environments, as well as a real-world weather prediction dataset. Comparisons with several other approaches are also included. Results indicate that Learn(++). NSE can track the changing environments very closely, regardless of the type of concept drift. To allow future use, comparison and benchmarking by interested researchers, we also release our data used in this paper. © 2011 IEEE

  19. Pulsar bi-drifting: implications for polar cap geometry

    Science.gov (United States)

    Wright, Geoff; Weltevrede, Patrick

    2017-01-01

    For many years it has been considered puzzling how pulsar radio emission, supposedly created by a circulating carousel of sub-beams, can produce the drift bands demonstrated by PSR J0815+0939, and more recently PSR B1839-04, which simultaneously drifts in opposing directions. Here, we suggest that the carousels of these pulsars, and hence their beams, are not circular but elliptical with axes tilted with respect to the fiducial plane. We show that certain relatively unusual lines of sight can cause bi-drifting to be observed, and a simulation of the two known exemplars is presented. Although bi-drifting is rare, non-circular beams may be common among pulsars and reveal themselves by having profile centroids displaced from the fiducial plane identified by polarization position angle swings. They may also result in profiles with asymmetric- and frequency-dependent component evolution. It is further suggested that the carousels may change their tilt by specific amounts and later reverse them. This may occur suddenly, accompanying a mode change (e.g. PSR B0943+10), or more gradually and short lived as in `flare' pulsars (e.g. PSR B1859+07). A range of pulsar behaviour (e.g. the shifting drift patterns of PSRs B0818-41 and B0826-34) may also be the result of non-circular carousels with varying orientation. The underlying nature of these carousels - whether they are exclusively generated by polar cap physics or driven by magnetospheric effects - is briefly discussed.

  20. Unstable universal drift eigenmodes in toroidal plasmas

    International Nuclear Information System (INIS)

    Cheng, C.Z.; Chen, L.

    1980-01-01

    The eigenmode equation describing ballooning collisionless drift instabilities is analyzed both analytically and numerically. A new branch of eigenmodes, which corresponds to quasi-bound states due to toroidal coupling effects such as ion delB drifts, is shown to be destabilized by electron Landau damping for typical tokamak parameters. This branch cannot be understood by the strong coupling approximation. However, the slab-like (Pearlstein--Berk-type) branch is found to remain stable and experience enhanced shear damping

  1. Cochlear implant: the family's perspective.

    Science.gov (United States)

    Vieira, Sheila de Souza; Dupas, Giselle; Chiari, Brasilia Maria

    2018-07-01

    To understand the family's experience of a child who uses a cochlear implant (CI). Specifically, to identify the difficulties, changes, and feelings entailed by deafness and the use of the CI; the coping strategies; and to understand the role of the family for the child with a CI. Qualitative research, using Symbolic Interactionism and Straussian Grounded Theory as the theoretical and methodological frameworks, respectively. Data collection instrument: semi-structured interview. A total of 9 families (32 individuals) participated in the study. The children's ages ranged from 6 to 11 years old (mean = 8.9 years old). Their experience is described in the following categories: Having to fight for results, Coping with difficult situations, Recognizing that you are not alone, Learning to overcome, and Having one's life restored by the implant. Cochlear implantation changes the direction of the child and the family's life by restoring the child's opportunity to hear and to obtain good results in her personal, social, and academic development. Even after implantation, the child continues to experience difficulties and requires the family's mobilization in order to be successful. The family is the principal actor in the process of the child's rehabilitation.

  2. Discovery of a remarkable subpulse drift pattern in PSR B0818-41

    Science.gov (United States)

    Bhattacharyya, B.; Gupta, Y.; Gil, J.; Sendyk, M.

    2007-05-01

    We report the discovery of a remarkable subpulse drift pattern in the relatively less-studied wide profile pulsar B0818-41 using high-sensitivity Giant Metrewave Radio Telescope (GMRT) observations. We find simultaneous occurrences of three drift regions with two different drift rates: an inner region with steeper apparent drift rate flanked on each side by a region of slower apparent drift rate. Furthermore, these closely spaced drift bands always maintain a constant phase relationship. Though these drift regions have significantly different values for the measured P2, the measured P3 value is the same and equal to 18.3P1. We interpret the unique drift pattern of this pulsar as being created by the intersection of our line of sight (LOS) with two conal rings on the polar cap of a fairly aligned rotator (inclination angle α ~ 11°), with an `inner' LOS geometry (impact angle ). We argue that both rings have the same values for the carousel rotation periodicity P4 and the number of sparks Nsp. We find that Nsp is 19-21 and show that it is very likely that P4 is the same as the measured P3, making it a truly unique pulsar. We present results from simulations of the radiation pattern using the inferred parameters, which support our interpretations and reproduce the average profile as well as the observed features in the drift pattern quite well.

  3. Thin hydroxyapatite surface layers on titanium produced by ion implantation

    CERN Document Server

    Baumann, H; Bilger, G; Jones, D; Symietz, I

    2002-01-01

    In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha,alpha) backscattering and the resonant nuclear reaction sup 1 H( sup 1 sup 5 N,alpha gamma) sup 1 sup 2 C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of m...

  4. Inland drift sand landscapes

    NARCIS (Netherlands)

    Fanta, J.; Siepel, H.

    2010-01-01

    Man has had a complex relationship with inland drift sands through the ages. For some centuries these landscapes were seen as a threat to society, especially agriculture and housing. At present we conserve these landscapes as important Natura 2000 priority habitats. In this book you may find these

  5. Dφ vertex drift chamber construction and test results

    International Nuclear Information System (INIS)

    Clark, A.R.; Goozen, F.; Grudberg, P.; Klopfenstein, C.; Kerth, L.T.; Loken, S.C.; Oltman, E.; Strovink, M.; Trippe, T.G.

    1991-05-01

    A jet-cell based vertex chamber has been built for the D OE experiment at Fermilab and operated in a test beam there. Low drift velocity and diffusion properties were achieved using CO 2 (95%)-ethane(5%) at atmospheric pressure. The drift velocity is found to be consistent with [9.74+8.68(|E|-1.25)] μm/nsec where E is the electric field strength in (kV/cm < |E| z 1.6 kV/cm.) An intrinsic spatial resolution of 60 μm or better for drift distances greater than 2 mm is measured. The track pair efficiency is estimated to be better than 90% for separations greater than 630 μm. 8 refs., 6 figs., 1 tab

  6. Drift velocity of free electrons in liquid argon

    International Nuclear Information System (INIS)

    Walkowiak, W.

    2000-01-01

    A measurement of the drift velocity of free electrons in liquid argon has been performed. Free electrons have been produced by photoelectric effect using laser light in a so-called 'laser chamber'. The results on the drift velocity v d are given as a function of the electric field strength in the range 0.5 kV/cm≤|E|≤12.6 kV/cm and the temperature in the range 87 K≤T≤94 K. A global parametrization of v d (|E|,T) has been fitted to the data. A temperature dependence of the electron drift velocity is observed, with a mean value of Δv d /(ΔT v d )=(-1.72±0.08)%/K in the range of 87-94 K

  7. The drift chamber system of the MEG experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Malte, E-mail: malte.hildebrandt@psi.c [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2010-11-01

    The MEG experiment searches for the lepton flavour violating decay {mu}{yields}e{gamma} and is aiming for a sensitivity of 10{sup -13} in the branching ratio in order to probe new physics beyond the standard model. The experiment is located at the Paul Scherrer Institut (PSI) in Switzerland, where one of the world's most intensive surface muon beams is located. Physics data taking started in September 2008. The drift chamber system is part of the innovative positron spectrometer of the MEG experiment and consists of 16 drift chamber modules. The system is designed to ensure precision measurement of 52.8 MeV/c positrons. Design, construction, geometrical alignment and performance of the drift chamber system are presented.

  8. Drift-scale thermomechanical analysis for the retrievability systems study

    International Nuclear Information System (INIS)

    Tsai, F.C.

    1996-01-01

    A numerical method was used to estimate the stability of potential emplacement drifts without considering a ground support system as a part of the Thermal Loading Systems Study for the Yucca Mountain Site Characterization Project. The stability of the drift is evaluated with two variables: the level of thermal loading and the diameter of the emplacement drift. The analyses include the thermomechanical effects generated by the excavation of the drift, subsequently by the thermal loads from heat-emitting waste packages, and finally by the thermal reduction resulting from rapid cooling ventilation required for the waste retrieval if required. The Discontinuous Deformation Analysis (DDA) code was used to analyze the thermomechanical response of the rock mass of multiple blocks separated by joints. The result of this stability analysis is used to discuss the geomechanical considerations for the advanced conceptual design (ACD) with respect to retrievability. In particular, based on the rock mass strength of the host rock described in the current version of the Reference Information Base, the computed thermal stresses, generated by 111 MTU/acre thermal loads in the near field at 100 years after waste emplacement, is beyond the criterion for the rock mass strength used to predict the stability of the rock mass surrounding the emplacement drift

  9. Drift Chambers Simulations in BM@N Experiment

    Directory of Open Access Journals (Sweden)

    Fedorišin Ján

    2016-01-01

    Full Text Available Drift chambers constitute an important part of the tracking system of the BM@N experiment designed to study the production of baryonic matter at the Nuclotron energies. GEANT programming package is employed to investigate the drift chamber response to particles produced in relativistic nuclear collisions of C+C nuclei, which are simulated by the UrQMD and LAQGSM Monte Carlo generators. These simulations are combined with the first BM@N experimental data to estimate particle track coordinates and their errors.

  10. Nonlinear drift waves in a dusty plasma with sheared flows

    Energy Technology Data Exchange (ETDEWEB)

    Vranjes, J. [K.U. Leuven (Belgium). Center for Plasma Astrophysics; Shukla, R.K. [Ruhr-Univ. Bochum (Germany). Inst. fuer Theoretische Physik IV

    2002-01-01

    Nonlinear properties of dust-modified drift waves and dust-drift waves in a dusty magnetoplasma with equilibrium sheared flows are examined. For this purpose, the relevant nonlinear equations for drift waves are analyzed for various profiles of the perpendicular and parallel plasma flows, and a variety of nonlinear solutions (viz. single and double vortex chains accompanied with zonal flows, tripolar and global vortices), which are driven by nommiform shear flows and nommiform dust density, is presented.

  11. Nonlinear drift waves in a dusty plasma with sheared flows

    International Nuclear Information System (INIS)

    Vranjes, J.; Shukla, R.K.

    2002-01-01

    Nonlinear properties of dust-modified drift waves and dust-drift waves in a dusty magnetoplasma with equilibrium sheared flows are examined. For this purpose, the relevant nonlinear equations for drift waves are analyzed for various profiles of the perpendicular and parallel plasma flows, and a variety of nonlinear solutions (viz. single and double vortex chains accompanied with zonal flows, tripolar and global vortices), which are driven by nommiform shear flows and nommiform dust density, is presented

  12. High pressure gas scintillation drift chambers with wave-shifter fiber readout

    International Nuclear Information System (INIS)

    Parsons, A.; Edberg, T.K.; Sadoulet, B.; Weiss, S.; Wilkerson, J.; Hurley, K.; Lin, R.P.

    1990-01-01

    The authors present results from a prototype high pressure xenon gas scintillation drift chamber using a novel wave-shifter fiber readout scheme. They have measured the primary scintillation light yield to be one photon per 76 ± 12 eV deposited energy. They present initial results of our chamber for the two-interaction separation (< 4 mm in the drift direction, ∼ 7 mm orthogonal to the drift); for the position resolution (< 400 μm rms in the plane orthogonal to the drift direction); and for the energy resolution (ΔE/E < 6% FWHM at 122 keV)

  13. Controlling qubit drift by recycling error correction syndromes

    Science.gov (United States)

    Blume-Kohout, Robin

    2015-03-01

    Physical qubits are susceptible to systematic drift, above and beyond the stochastic Markovian noise that motivates quantum error correction. This parameter drift must be compensated - if it is ignored, error rates will rise to intolerable levels - but compensation requires knowing the parameters' current value, which appears to require halting experimental work to recalibrate (e.g. via quantum tomography). Fortunately, this is untrue. I show how to perform on-the-fly recalibration on the physical qubits in an error correcting code, using only information from the error correction syndromes. The algorithm for detecting and compensating drift is very simple - yet, remarkably, when used to compensate Brownian drift in the qubit Hamiltonian, it achieves a stabilized error rate very close to the theoretical lower bound. Against 1/f noise, it is less effective only because 1/f noise is (like white noise) dominated by high-frequency fluctuations that are uncompensatable. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE

  14. The KLOE drift chamber

    International Nuclear Information System (INIS)

    Ferrari, A.

    2002-01-01

    The design and construction of the large drift chamber of the KLOE experiment is presented. The track reconstruction is described, together with the calibration method and the monitoring systems. The stability of operation and the performance are studied with samples of e + e - , K S K L and K + K - events

  15. Guiding center drift equations

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1979-03-01

    The quations for particle guiding center drift orbits are given in a new magnetic coordinate system. This form of the equations not only separates the fast motion along the lines from the slow motion across, but also requires less information about the magnetic field than many other formulations of the problem

  16. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    International Nuclear Information System (INIS)

    Dixon, P.

    2004-01-01

    The purpose of this Model Report (REV02) is to document the unsaturated zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrological-chemical (THC) processes on UZ flow and transport. This Model Report has been developed in accordance with the ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this Model Report in Section 1.12, Work Package AUZM08, ''Coupled Effects on Flow and Seepage''. The plan for validation of the models documented in this Model Report is given in Attachment I, Model Validation Plans, Section I-3-4, of the TWP. Except for variations in acceptance criteria (Section 4.2), there were no deviations from this TWP. This report was developed in accordance with AP-SIII.10Q, ''Models''. This Model Report documents the THC Seepage Model and the Drift Scale Test (DST) THC Model. The THC Seepage Model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC model is a drift-scale process model relying on the same conceptual model and much of the same input data (i.e., physical, hydrological, thermodynamic, and kinetic) as the THC Seepage Model. The DST THC Model is the primary method for validating the THC Seepage Model. The DST THC Model compares predicted water and gas compositions, as well as mineral alteration patterns, with observed data from the DST. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal-loading conditions, and predict the evolution of mineral alteration and fluid chemistry around potential waste emplacement drifts. The DST THC Model is used solely for the validation of the THC

  17. Using different drift gases to change separation factors (alpha) in ion mobility spectrometry

    Science.gov (United States)

    Asbury; Hill

    2000-02-01

    The use of different drift gases to alter separation factors (alpha) in ion mobility spectrometry has been demonstrated. The mobility of a series of low molecular weight compounds and three small peptides was determined in four different drift gases. The drift gases chosen were helium, argon, nitrogen, and carbon dioxide. These drift gases provide a range of polarizabilities and molecular weights. In all instances, the compounds showed the greatest mobility in helium and the lowest mobility in carbon dioxide; however the percentage change of mobility for each compound was different, effectively changing the alpha value. The alpha value changes were primarily due to differences in drift gas polarizability but were also influenced by the mass of the drift gas. In addition, gas-phase ion radii were calculated in each of the different drift gases. These radii were then plotted against drift gas polarizability producing linear plots with r2 values greater than 0.99. The intercept of these plots provides the gas-phase radius of an ion in a nonpolarizing environment, whereas the slope is indicative of the magnitude of the ion's mobility change related to polarizability. It therefore, should be possible to separate any two compounds that have different slopes with the appropriate drift gas.

  18. Modeling spray drift and runoff-related inputs of pesticides to receiving water.

    Science.gov (United States)

    Zhang, Xuyang; Luo, Yuzhou; Goh, Kean S

    2018-03-01

    Pesticides move to surface water via various pathways including surface runoff, spray drift and subsurface flow. Little is known about the relative contributions of surface runoff and spray drift in agricultural watersheds. This study develops a modeling framework to address the contribution of spray drift to the total loadings of pesticides in receiving water bodies. The modeling framework consists of a GIS module for identifying drift potential, the AgDRIFT model for simulating spray drift, and the Soil and Water Assessment Tool (SWAT) for simulating various hydrological and landscape processes including surface runoff and transport of pesticides. The modeling framework was applied on the Orestimba Creek Watershed, California. Monitoring data collected from daily samples were used for model evaluation. Pesticide mass deposition on the Orestimba Creek ranged from 0.08 to 6.09% of applied mass. Monitoring data suggests that surface runoff was the major pathway for pesticide entering water bodies, accounting for 76% of the annual loading; the rest 24% from spray drift. The results from the modeling framework showed 81 and 19%, respectively, for runoff and spray drift. Spray drift contributed over half of the mass loading during summer months. The slightly lower spray drift contribution as predicted by the modeling framework was mainly due to SWAT's under-prediction of pesticide mass loading during summer and over-prediction of the loading during winter. Although model simulations were associated with various sources of uncertainties, the overall performance of the modeling framework was satisfactory as evaluated by multiple statistics: for simulation of daily flow, the Nash-Sutcliffe Efficiency Coefficient (NSE) ranged from 0.61 to 0.74 and the percent bias (PBIAS) runoff in receiving waters and the design of management practices for mitigating pesticide exposure within a watershed. Published by Elsevier Ltd.

  19. Simulation study of a high power density rectenna array for biomedical implantable devices

    Science.gov (United States)

    Day, John; Yoon, Hargsoon; Kim, Jaehwan; Choi, Sang H.; Song, Kyo D.

    2016-04-01

    The integration of wireless power transmission devices using microwaves into the biomedical field is close to a practical reality. Implanted biomedical devices need a long lasting power source or continuous power supply. Recent development of high efficiency rectenna technology enables continuous power supply to these implanted devices. Due to the size limit of most of medical devices, it is imperative to minimize the rectenna as well. The research reported in this paper reviews the effects of close packing the rectenna elements which show the potential of directly empowering the implanted devices, especially within a confined area. The rectenna array is tested in the X band frequency range.

  20. An effective drift correction for dynamical downscaling of decadal global climate predictions

    Science.gov (United States)

    Paeth, Heiko; Li, Jingmin; Pollinger, Felix; Müller, Wolfgang A.; Pohlmann, Holger; Feldmann, Hendrik; Panitz, Hans-Jürgen

    2018-04-01

    Initialized decadal climate predictions with coupled climate models are often marked by substantial climate drifts that emanate from a mismatch between the climatology of the coupled model system and the data set used for initialization. While such drifts may be easily removed from the prediction system when analyzing individual variables, a major problem prevails for multivariate issues and, especially, when the output of the global prediction system shall be used for dynamical downscaling. In this study, we present a statistical approach to remove climate drifts in a multivariate context and demonstrate the effect of this drift correction on regional climate model simulations over the Euro-Atlantic sector. The statistical approach is based on an empirical orthogonal function (EOF) analysis adapted to a very large data matrix. The climate drift emerges as a dramatic cooling trend in North Atlantic sea surface temperatures (SSTs) and is captured by the leading EOF of the multivariate output from the global prediction system, accounting for 7.7% of total variability. The SST cooling pattern also imposes drifts in various atmospheric variables and levels. The removal of the first EOF effectuates the drift correction while retaining other components of intra-annual, inter-annual and decadal variability. In the regional climate model, the multivariate drift correction of the input data removes the cooling trends in most western European land regions and systematically reduces the discrepancy between the output of the regional climate model and observational data. In contrast, removing the drift only in the SST field from the global model has hardly any positive effect on the regional climate model.

  1. Using Institutional Theory To Reframe Research on Academic Drift.

    Science.gov (United States)

    Morphew, Christopher C.; Huisman, Jeroen

    2002-01-01

    Examines patterns of academic drift (a drift toward the structure and norms typical of more prestigious universities) in multiple higher education systems and tests the concept of "isomorphism in organizational fields" as discussed in institutional theory. Argues that the theoretical framework provided by institutional theory presents a useful…

  2. Approximation of the characteristics of ion drift in parent gas

    Energy Technology Data Exchange (ETDEWEB)

    Golyatina, R. I.; Maiorov, S. A., E-mail: mayorov-sa@mail.ru [Russian Academy of Science, Prokhorov General Physics Institute (Russian Federation)

    2017-01-15

    The drift velocities of noble-gas and mercury ions in a constant homogeneous electric field are calculated using Monte Carlo simulations. The ion mobility is analyzed as a function of the field strength and gas temperature. The fitting parameters for calculating the drift velocity by the Frost formula at gas temperatures of 4.2, 77, 300, 1000, and 2000 K are obtained. A general approximate formula for the drift velocity as a function of the reduced field and gas temperature is derived.

  3. Modeling of Drift Effects on Solar Tower Concentrated Flux Distributions

    Directory of Open Access Journals (Sweden)

    Luis O. Lara-Cerecedo

    2016-01-01

    Full Text Available A novel modeling tool for calculation of central receiver concentrated flux distributions is presented, which takes into account drift effects. This tool is based on a drift model that includes different geometrical error sources in a rigorous manner and on a simple analytic approximation for the individual flux distribution of a heliostat. The model is applied to a group of heliostats of a real field to obtain the resulting flux distribution and its variation along the day. The distributions differ strongly from those obtained assuming the ideal case without drift or a case with a Gaussian tracking error function. The time evolution of peak flux is also calculated to demonstrate the capabilities of the model. The evolution of this parameter also shows strong differences in comparison to the case without drift.

  4. Beneficial aspects of real time flow measurements for the management of acute right ventricular heart failure following continuous flow ventricular assist device implantation

    Directory of Open Access Journals (Sweden)

    Spiliopoulos Sotirios

    2012-11-01

    Full Text Available Abstract Background Optimal management of acute right heart failure following the implantation of a left ventricular assist device requires a reliable estimation of left ventricular preload and contractility. This is possible by real-time pump blood flow measurements. Clinical case We performed implantation of a continuous flow left ventricular assist device in a 66 years old female patient with an end-stage heart failure on the grounds of a dilated cardiomyopathy. Real-time pump blood flow was directly measured by an ultrasonic flow probe placed around the outflow graft. Diagnosis The progressive decline of real time flow and the loss of pulsatility were associated with an increase of central venous pressure, inotropic therapy and progressive renal failure suggesting the presence of an acute right heart failure. Diagnosis was validated by echocardiography and thermodilution measurements. Treatment Temporary mechanical circulatory support of the right ventricle was successfully performed. Real time flow measurement proved to be a useful tool for the diagnosis and ultimately for the management of right heart failure including the weaning from extracorporeal membrane oxygenation.

  5. Diffusion and drift of charges in semiconductor detectors

    International Nuclear Information System (INIS)

    Meidinger, N.

    1991-01-01

    For this analysis, a fully depleteable pn-CCD (a novel, energy and local resolution semiconductor using the drift chamber principle) has been tested for verification at different temperatures, photon energies, and drift times, including theoretical calculations. Experimental results are in good agreement with calculated data, and deviations (≤11%) have been understood to an extent that proposals can be made for improving the accuracy. Charge splitting has been found to be reduced in the case of reduced charge collecting areas, i.e. for example at lower temperatures, or with shorter drift times. This effect is also reduced in the case of larger charge collecting areas (pixels). With the given topology of the cell structure, the charge splitting can be much more strongly suppressed as compared to other X-ray CCD design types. (orig.) [de

  6. Drift compression and final focus systems for heavy ion inertial fusion

    Energy Technology Data Exchange (ETDEWEB)

    de Hoon, Michiel Jan Laurens [Univ. of California, Berkeley, CA (United States)

    2001-01-01

    Longitudinal compression of space-charge dominated beams can be achieved by imposing a head-to-tail velocity tilt on the beam. This tilt has to be carefully tailored, such that it is removed by the longitudinal space-charge repulsion by the time the beam reaches the end of the drift compression section. The transverse focusing lattice should be designed such that all parts of the beam stay approximately matched, while the beam smoothly expands transversely to the larger beam radius needed in the final focus system following drift compression. In this thesis, several drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression. The occurrence of mismatches due to a rapidly increasing current was analyzed. In addition, the sensitivity of drift compression to errors in the initial velocity tilt and current profile was studied. These calculations were done using a new computer code that accurately calculates the longitudinal electric field in the space-charge dominated regime.

  7. Perturbed GUE Minor Process and Warren's Process with Drifts

    Science.gov (United States)

    Ferrari, Patrik L.; Frings, René

    2014-01-01

    We consider the minor process of (Hermitian) matrix diffusions with constant diagonal drifts. At any given time, this process is determinantal and we provide an explicit expression for its correlation kernel. This is a measure on the Gelfand-Tsetlin pattern that also appears in a generalization of Warren's process (Electron. J. Probab. 12:573-590, 2007), in which Brownian motions have level-dependent drifts. Finally, we show that this process arises in a diffusion scaling limit from an interacting particle system in the anisotropic KPZ class in 2+1 dimensions introduced in Borodin and Ferrari (Commun. Math. Phys., 2008). Our results generalize the known results for the zero drift situation.

  8. Studies of dynamics of electron clouds in STAR silicon drift detectors

    CERN Document Server

    Bellwied, R; Brandon, N; Caines, H; Chen, W; Dimassimo, D; Dyke, H; Hall, J R; Hardtke, D; Hoffmann, G W; Humanic, T J; Kotova, A I; Kotov, I V; Kraner, H W; Li, Z; Lynn, D; Middelkamp, P; Ott, G; Pandey, S U; Pruneau, C A; Rykov, V L; Schambach, J; Sedlmeir, J; Sugarbaker, E R; Takahashi, J; Wilson, W K

    2000-01-01

    The dynamics of electrons generated in silicon drift detectors was studied using an IR LED. Electrons were generated at different drift distances. In this way, the evolution of the cloud as a function of drift time was measured. Two methods were used to measure the cloud size. The method of cumulative functions was used to extract the electron cloud profiles. Another method obtains the cloud width from measurements of the charge collected on a single anode as a function of coordinate of the light spot. The evolution of the electron cloud width with drift time is compared with theoretical calculations. Experimental results agreed with theoretical expectations.

  9. Ion implantation

    International Nuclear Information System (INIS)

    Dearnaley, Geoffrey

    1975-01-01

    First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

  10. Double site-bond percolation model for biomaterial implants

    OpenAIRE

    Mely, H.; Mathiot, J. -F.

    2011-01-01

    9 figures - 10 pages; We present a double site-bond percolation model to account, on the one hand, for the vascularization and/or resorption of biomaterial implant in bones, and on the other hand, for its mechanical continuity. The transformation of the implant into osseous material, and the dynamical formation/destruction of this osseous material is accounted for by creation and destruction of links and sites in two, entangled, networks. We identify the relevant parameters to describe the im...

  11. The Study of Westward Drift in the Main Geomagnetic Field

    OpenAIRE

    Bayanjargal, G.

    2013-01-01

    We have obtained a solution for the velocity of westward drift from the induction equation in which an approach for main geomagnetic field was built. Distribution functions B(r, t) entered into the induction equation have been built by the observatories' data in North America and the Europe from 1991 to 2006. The longitudinal −0.123 degree/year and latitudinal 0.068 degree/year drifts were defined in North America. And the longitudinal −0.257 degree/year drift was defined in Europe from 1991...

  12. Drift-Implicit Multi-Level Monte Carlo Tau-Leap Methods for Stochastic Reaction Networks

    KAUST Repository

    Ben Hammouda, Chiheb

    2015-05-12

    In biochemical systems, stochastic e↵ects can be caused by the presence of small numbers of certain reactant molecules. In this setting, discrete state-space and stochastic simulation approaches were proved to be more relevant than continuous state-space and deterministic ones. These stochastic models constitute the theory of stochastic reaction networks (SRNs). Furthermore, in some cases, the dynamics of fast and slow time scales can be well separated and this is characterized by what is called sti↵ness. For such problems, the existing discrete space-state stochastic path simulation methods, such as the stochastic simulation algorithm (SSA) and the explicit tau-leap method, can be very slow. Therefore, implicit tau-leap approxima- tions were developed to improve the numerical stability and provide more e cient simulation algorithms for these systems. One of the interesting tasks for SRNs is to approximate the expected values of some observables of the process at a certain fixed time T. This is can be achieved using Monte Carlo (MC) techniques. However, in a recent work, Anderson and Higham in 2013, proposed a more computationally e cient method which combines multi-level Monte Carlo (MLMC) technique with explicit tau-leap schemes. In this MSc thesis, we propose new fast stochastic algorithm, particularly designed 5 to address sti↵ systems, for approximating the expected values of some observables of SRNs. In fact, we take advantage of the idea of MLMC techniques and drift-implicit tau-leap approximation to construct a drift-implicit MLMC tau-leap estimator. In addition to accurately estimating the expected values of a given observable of SRNs at a final time T , our proposed estimator ensures the numerical stability with a lower cost than the MLMC explicit tau-leap algorithm, for systems including simultane- ously fast and slow species. The key contribution of our work is the coupling of two drift-implicit tau-leap paths, which is the basic brick for

  13. A Pascalian lateral drift sensor

    International Nuclear Information System (INIS)

    Jansen, H.

    2016-01-01

    A novel concept of a layer-wise produced semiconductor sensor for precise particle tracking is proposed herein. In contrast to common semiconductor sensors, local regions with increased doping concentration deep in the bulk termed charge guides increase the lateral drift of free charges on their way to the read-out electrode. This lateral drift enables charge sharing independent of the incident position of the traversing particle. With a regular grid of charge guides the lateral charge distribution resembles a normalised Pascal's triangle for particles that are stopped in depths lower than the depth of the first layer of the charge guides. For minimum ionising particles a sum of binomial distributions describes the lateral charge distribution. This concept decouples the achievable sensor resolution from the pitch size as the characteristic length is replaced by the lateral distance of the charge guides.

  14. ATLAS Muon Drift Tube Electronics

    CERN Document Server

    Arai, Y; Beretta, M; Boterenbrood, H; Brandenburg, G W; Ceradini, F; Chapman, J W; Dai, T; Ferretti, C; Fries, T; Gregory, J; Guimarães da Costa, J; Harder, S; Hazen, E; Huth, J; Jansweijer, P P M; Kirsch, L E; König, A C; Lanza, A; Mikenberg, G; Oliver, J; Posch, C; Richter, R; Riegler, W; Spiriti, E; Taylor, F E; Vermeulen, J; Wadsworth, B; Wijnen, T A M

    2008-01-01

    This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 microns, which corresponds to a momentum accuracy of about 10% at pT = 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

  15. A Pascalian lateral drift sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, H., E-mail: hendrik.jansen@desy.de

    2016-09-21

    A novel concept of a layer-wise produced semiconductor sensor for precise particle tracking is proposed herein. In contrast to common semiconductor sensors, local regions with increased doping concentration deep in the bulk termed charge guides increase the lateral drift of free charges on their way to the read-out electrode. This lateral drift enables charge sharing independent of the incident position of the traversing particle. With a regular grid of charge guides the lateral charge distribution resembles a normalised Pascal's triangle for particles that are stopped in depths lower than the depth of the first layer of the charge guides. For minimum ionising particles a sum of binomial distributions describes the lateral charge distribution. This concept decouples the achievable sensor resolution from the pitch size as the characteristic length is replaced by the lateral distance of the charge guides.

  16. Intracranial EEG fluctuates over months after implanting electrodes in human brain

    Science.gov (United States)

    Ung, Hoameng; Baldassano, Steven N.; Bink, Hank; Krieger, Abba M.; Williams, Shawniqua; Vitale, Flavia; Wu, Chengyuan; Freestone, Dean; Nurse, Ewan; Leyde, Kent; Davis, Kathryn A.; Cook, Mark; Litt, Brian

    2017-10-01

    Objective. Implanting subdural and penetrating electrodes in the brain causes acute trauma and inflammation that affect intracranial electroencephalographic (iEEG) recordings. This behavior and its potential impact on clinical decision-making and algorithms for implanted devices have not been assessed in detail. In this study we aim to characterize the temporal and spatial variability of continuous, prolonged human iEEG recordings. Approach. Intracranial electroencephalography from 15 patients with drug-refractory epilepsy, each implanted with 16 subdural electrodes and continuously monitored for an average of 18 months, was included in this study. Time and spectral domain features were computed each day for each channel for the duration of each patient’s recording. Metrics to capture post-implantation feature changes and inflexion points were computed on group and individual levels. A linear mixed model was used to characterize transient group-level changes in feature values post-implantation and independent linear models were used to describe individual variability. Main results. A significant decline in features important to seizure detection and prediction algorithms (mean line length, energy, and half-wave), as well as mean power in the Berger and high gamma bands, was observed in many patients over 100 d following implantation. In addition, spatial variability across electrodes declines post-implantation following a similar timeframe. All selected features decreased by 14-50% in the initial 75 d of recording on the group level, and at least one feature demonstrated this pattern in 13 of the 15 patients. Our findings indicate that iEEG signal features demonstrate increased variability following implantation, most notably in the weeks immediately post-implant. Significance. These findings suggest that conclusions drawn from iEEG, both clinically and for research, should account for spatiotemporal signal variability and that properly assessing the iEEG in

  17. Drift estimation from a simple field theory

    International Nuclear Information System (INIS)

    Mendes, F. M.; Figueiredo, A.

    2008-01-01

    Given the outcome of a Wiener process, what can be said about the drift and diffusion coefficients? If the process is stationary, these coefficients are related to the mean and variance of the position displacements distribution. However, if either drift or diffusion are time-dependent, very little can be said unless some assumption about that dependency is made. In Bayesian statistics, this should be translated into some specific prior probability. We use Bayes rule to estimate these coefficients from a single trajectory. This defines a simple, and analytically tractable, field theory.

  18. Nonlinear dynamics of resistive electrostatic drift waves

    DEFF Research Database (Denmark)

    Korsholm, Søren Bang; Michelsen, Poul; Pécseli, H.L.

    1999-01-01

    The evolution of weakly nonlinear electrostatic drift waves in an externally imposed strong homogeneous magnetic field is investigated numerically in three spatial dimensions. The analysis is based on a set of coupled, nonlinear equations, which are solved for an initial condition which is pertur......The evolution of weakly nonlinear electrostatic drift waves in an externally imposed strong homogeneous magnetic field is investigated numerically in three spatial dimensions. The analysis is based on a set of coupled, nonlinear equations, which are solved for an initial condition which...... polarity, i.e. a pair of electrostatic convective cells....

  19. Drift tubes of Linac 2

    CERN Multimedia

    Photographic Service

    1977-01-01

    Being redied for installation, those at the right are for tank 1, those on the left for tank 2. Contrary to Linac 1, which had drift-tubes supported on stems, here the tubes are suspended, for better mechanical stability.

  20. Interception and retention of simulated cooling tower drift by vegetation

    International Nuclear Information System (INIS)

    Taylor, F.G. Jr.; Parr, P.D.

    1978-01-01

    A key issue concerning environmental impacts from cooling tower operation is the interception of drift by vegetation and the efficiency of plants in retaining the residue scavenged from the atmosphere. Chromated drift water, typical of the cooling towers of the Department of Energy's uranium enrichment facilities at Oak Ridge, Tennessee, was prepared using radio-labelled chromium. A portable aerosol generator was used to produce a spectrum of droplets with diameters (100 to 1300 μ) characteristic of cooling towers using state-of-the-art drift eliminators. Efficiency of interception by foliage varied according to leaf morphology with yellow poplar seedlings intercepting 72% of the deposition mass in contrast to 45% by loblolly pine and 24% by fescue grass. Retention patterns of intercepted deposition consisted of a short-time component (0 to 3 days) and a long-time component (3 to 63 days). Retention times, estimated from the regression equation of the long component, indicated that drift contamination from any deposition event may persist from between 8 and 12 weeks. In field situations adjacent to cooling towers, the average annual concentration of drift on vegetation at any distance remains relatively constant, with losses from weathering being compensated by chronic deposition

  1. Post-annealing recrystallization and damage recovery process in Fe ion implanted Si

    International Nuclear Information System (INIS)

    Naito, Muneyuki; Hirata, Akihiko; Ishimaru, Manabu; Hirotsu, Yoshihiko

    2007-01-01

    We have investigated ion-beam-induced and thermal annealing-induced microstructures in high fluence Fe implanted Si using transmission electron microscopy. Si(1 1 1) substrates were irradiated with 120 keV Fe ions at 120 K to fluences of 0.4 x 10 17 and 4.0 x 10 17 cm -2 . A continuous amorphous layer was formed on Si substrates in both as-implanted samples. After thermal annealing at 1073 K for 2 h, β-FeSi 2 fine particles buried in a polycrystalline Si layer were observed in the low fluence sample, while a continuous β-FeSi 2 layer was formed in the high fluence sample. We discuss the relationship between ion fluence and defects recovery process in Fe ion implanted Si

  2. Stabilizing effects of hot electrons on low frequency plasma drift waves

    International Nuclear Information System (INIS)

    Huang Chaosong; Qiu Lijian; Ren Zhaoxing

    1988-01-01

    The MHD equation is used to study the stabilization of low frequency drift waves driven by density gradient of plasma in a hot electron plasma. The dispersion relation is derived, and the stabilizing effects of hot electrons are discussed. The physical mechanism for hot electron stabilization of the low frequency plasma perturbations is charge uncovering due to the hot electron component, which depends only on α, the ratio of N h /N i , but not on the value of β h . The hot electrons can reduce the growth rate of the interchange mode and drift wave driven by the plasma, and suppress the enomalous plasma transport caused by the drift wave. Without including the effectof β h , the stabilization of the interchange mode requires α≅2%, and the stabilization of the drift wave requires α≅40%. The theoretical analyses predict that the drift wave is the most dangerous low frequency instability in the hot electron plasma

  3. Operational SAR-based sea ice drift monitoring over the Baltic Sea

    Directory of Open Access Journals (Sweden)

    J. Karvonen

    2012-07-01

    Full Text Available An algorithm for computing ice drift from pairs of synthetic aperture radar (SAR images covering a common area has been developed at FMI. The algorithm has been developed based on the C-band SAR data over the Baltic Sea. It is based on phase correlation in two scales (coarse and fine with some additional constraints. The algorithm has been running operationally in the Baltic Sea from the beginning of 2011, using Radarsat-1 ScanSAR wide mode and Envisat ASAR wide swath mode data. The resulting ice drift fields are publicly available as part of the MyOcean EC project. The SAR-based ice drift vectors have been compared to the drift vectors from drifter buoys in the Baltic Sea during the first operational season, and also these validation results are shown in this paper. Also some navigationally useful sea ice quantities, which can be derived from ice drift vector fields, are presented.

  4. Development of Implantable Medical Devices: From an Engineering Perspective

    Directory of Open Access Journals (Sweden)

    Yeun-Ho Joung

    2013-09-01

    Full Text Available From the first pacemaker implant in 1958, numerous engineering and medical activities for implantable medical device development have faced challenges in materials, battery power, functionality, electrical power consumption, size shrinkage, system delivery, and wireless communication. With explosive advances in scientific and engineering technology, many implantable medical devices such as the pacemaker, cochlear implant, and real-time blood pressure sensors have been developed and improved. This trend of progress in medical devices will continue because of the coming super-aged society, which will result in more consumers for the devices. The inner body is a special space filled with electrical, chemical, mechanical, and marine-salted reactions. Therefore, electrical connectivity and communication, corrosion, robustness, and hermeticity are key factors to be considered during the development stage. The main participants in the development stage are the user, the medical staff, and the engineer or technician. Thus, there are three different viewpoints in the development of implantable devices. In this review paper, considerations in the development of implantable medical devices will be presented from the viewpoint of an engineering mind.

  5. Eelgrass re-establishment in shallow estuaries is affected by drifting macroalgae

    DEFF Research Database (Denmark)

    Canal-Verges, Paula; Potthoff, M.; Hansen, F. T.

    2014-01-01

    surface sediment. Furthermore, drifting macroalgae ballistically damage eelgrass beds and increase seedling mortality. The frequency and impact of drifting macroalgae in Odense Fjord was evaluated with an agent-based model. The aims of this model were to understand and predict the mobility...... resuspension in bare bottoms and on rooted vegetation due to ballistic impacts in areas affected by algae drift. (C) 2013 Elsevier B.V. All rights reserved....

  6. Pulsar magnetic alignment. The drifting subpulses

    International Nuclear Information System (INIS)

    Jones, P.B.

    1977-01-01

    According to Ruderman and Sutherland (Ap.J.;196:51 (1975)) the subpulse drift observed in certain pulsars is a consequence of the circulation around the magnetic axis of electron-positron discharges occurring within an acceleration region near the polar cap. The predicted period of circulation P 3 is of the correct order of magnitude, but the sense of circulation and therefore the direction of subpulse drift is not consistent with indirect evidence, from observed integrated pulse widths, on the variation with pulsar age of the angle between the spin and magnetic axes. It is shown that this problem is resolved by a model of the acceleration electric field based on space charge limited ion flow. (author)

  7. Radiation stress and mean drift in continental shelf waves

    Science.gov (United States)

    Weber, Jan Erik H.; Drivdal, Magnus

    2012-03-01

    The time- and depth-averaged mean drift induced by barotropic continental shelf waves (CSW's) is studied theoretically for idealized shelf topography by calculating the mean volume fluxes to second order in wave amplitude. The waves suffer weak spatial damping due to bottom friction, which leads to radiation stress forcing of the mean fluxes. In terms of the total wave energy density E̅̅ over the shelf region, the radiation stress tensor component S̅11 for CSW's is found to be different from that of shallow water surface waves in a non-rotating ocean. For CSW's, the ratio S̅11/E̅ depends strongly on the wave number. The mean Lagrangian flow forced by the radiation stress can be subdivided into a Stokes drift and a mean Eulerian drift current. The magnitude of latter depends on ratio between the radiation stress and the bottom stress acting on the mean flow. When the effect of bottom friction acts equally strong on the waves and the mean current, calculations for short CSW's show that the Stokes drift and the friction-dependent wave-induced mean Eulerian current varies approximately in anti-phase over the shelf, and that the latter is numerically the largest. For long CSW's they are approximately in phase. In both cases the mean Lagrangian current, which is responsible for the net particle drift, has its largest numerical value at the coast on the shallow part of the shelf. Enhancing the effect of bottom friction on the Eulerian mean flow, results in a general current speed reduction, as well as a change in spatial structure for long waves. Applying realistic physical parameters for the continental shelf west of Norway, calculations yield along-shelf mean drift velocities for short CSW's that may be important for the transport of biological material, neutral tracers, and underwater plumes of dissolved oil from deepwater drilling accidents.

  8. Studies of electron drift velocity in nitrogen and isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Pontificia Univ. Catolica de Sao Paulo (PUC/SP), SP (Brazil); Vivaldini, Tulio C.; Lima, Iara B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Fonte, Paulo; Mangiarotti, Alessio [Universidade de Coimbra (Portugal). Dept. de fisica. Lab. de Instrumentacao e Fisica Experimental de Particulas

    2009-07-01

    Full text: The electron drift velocity is one of the most important transport parameters used to describe the physical behaviour of gas discharges and the development of avalanches in gaseous detectors, mainly when temporal information is significant, as in drift chambers and in the recent Resistive Plate Chambers (RPCs). Although many filling gases, isobutane is frequently used in RPCs, due to its excellent timing properties, but at high electric fields conditions there are insufficient data available in literature. In the present work we report the preliminary results related to the dependence of the electron drift velocity for isobutane as function of the reduced electric field E/N, in the range of 100 Td up to 216 Td. There are different methods to determine electron drift velocity in a gas, and our measurements were based on the Pulsed Townsend technique, which consists of extracting electrons from a metallic cathode and accelerates them toward the anode by a uniform electric field. Once the drift distance and the transit time are known, the drift velocities can be determined. In our system, the incidence of a nitrogen laser beam (LTB MNL200-LD) liberates electron from the cathode made of aluminium (40mm diameter). By means of a high voltage supply (Bertan, 225-30), these electrons are accelerated toward the anode (made of a high resistivity glass - 2:10{sup 12}{omega} cm) and this movement produces a fast electric signal in the anode, which is digitalized in an oscilloscope (LeCroy WavePro 7000) with 1 GHz bandwidth and 10 GS/s. The values obtained were compared to that ones of a Bolsig+ simulation code. In order to validate the technique and to analyze non-uniformity effects, results for nitrogen are also presented. (author)

  9. Studies of electron drift velocity in nitrogen and isobutane

    International Nuclear Information System (INIS)

    Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B.; Vivaldini, Tulio C.; Lima, Iara B.; Ridenti, Marco A.; Pascholati, Paulo R.; Fonte, Paulo; Mangiarotti, Alessio

    2009-01-01

    Full text: The electron drift velocity is one of the most important transport parameters used to describe the physical behaviour of gas discharges and the development of avalanches in gaseous detectors, mainly when temporal information is significant, as in drift chambers and in the recent Resistive Plate Chambers (RPCs). Although many filling gases, isobutane is frequently used in RPCs, due to its excellent timing properties, but at high electric fields conditions there are insufficient data available in literature. In the present work we report the preliminary results related to the dependence of the electron drift velocity for isobutane as function of the reduced electric field E/N, in the range of 100 Td up to 216 Td. There are different methods to determine electron drift velocity in a gas, and our measurements were based on the Pulsed Townsend technique, which consists of extracting electrons from a metallic cathode and accelerates them toward the anode by a uniform electric field. Once the drift distance and the transit time are known, the drift velocities can be determined. In our system, the incidence of a nitrogen laser beam (LTB MNL200-LD) liberates electron from the cathode made of aluminium (40mm diameter). By means of a high voltage supply (Bertan, 225-30), these electrons are accelerated toward the anode (made of a high resistivity glass - 2:10 12 Ω cm) and this movement produces a fast electric signal in the anode, which is digitalized in an oscilloscope (LeCroy WavePro 7000) with 1 GHz bandwidth and 10 GS/s. The values obtained were compared to that ones of a Bolsig+ simulation code. In order to validate the technique and to analyze non-uniformity effects, results for nitrogen are also presented. (author)

  10. Solitary drift waves in the presence of magnetic shear

    International Nuclear Information System (INIS)

    Meiss, J.D.; Horton, W.

    1982-07-01

    The two-component fluid equations describing electron drift and ion acoustic waves in a nonuniform magnetized plasma are shown to possess nonlinear two-dimensional solitary wave solutions. In the presence of magnetic shear, radiative shear damping is exponentially small in L/sub s//L/sub n/ for solitary drift waves, in contrast to linear waves

  11. Observation and analysis of pellet material del B drift on MAST

    Energy Technology Data Exchange (ETDEWEB)

    Garzotti, L. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Baylor, Larry R [ORNL; Kochi, F. [Austrian Academy of Sciences, Vienna, Austria; Pegourie, B. [CEA Cadarache, St. Paul lex Durance, France; Valovic, M [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Axon, K. B. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Dowling, J. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Guri, C. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Maddison, G. P. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Nehme, H. [CEA Cadarache, St. Paul lex Durance, France; O' Gorman, T. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Patel, A. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Price, M. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Scannell, R. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England; Walsh, M. [EURATOM, Culham Sci Ctr, Abingdon, Oxon England

    2010-01-01

    Pellet material deposited in a tokamak plasma experiences a drift towards the low field side of the torus induced by the magnetic field gradient. Plasma fuelling in ITER relies on the beneficial effect of this drift to increase the pellet deposition depth and fuelling efficiency. It is therefore important to analyse this phenomenon in present machines to improve the understanding of the del B induced drift and the accuracy of the predictions for ITER. This paper presents a detailed analysis of pellet material drift in MAST pellet injection experiments based on the unique diagnostic capabilities available on this machine and compares the observations with predictions of state-of-the-art ablation and deposition codes.

  12. Surface sputtering in high-dose Fe ion implanted Si

    International Nuclear Information System (INIS)

    Ishimaru, Manabu

    2007-01-01

    Microstructures and elemental distributions in high-dose Fe ion implanted Si were characterized by means of transmission electron microscopy and Rutherford backscattering spectroscopy. Single crystalline Si(0 0 1) substrates were implanted at 350 deg. C with 120 keV Fe ions to fluences ranging from 0.1 x 10 17 to 4.0 x 10 17 /cm 2 . Extensive damage induced by ion implantation was observed inside the substrate below 1.0 x 10 17 /cm 2 , while a continuous iron silicide layer was formed at 4.0 x 10 17 /cm 2 . It was found that the spatial distribution of Fe projectiles drastically changes at the fluence between 1.0 x 10 17 and 4.0 x 10 17 /cm 2 due to surface sputtering during implantation

  13. Curvature-induced electrostatic drift modes in a toroidal plasma

    International Nuclear Information System (INIS)

    Venema, M.

    1985-01-01

    This thesis deals with a number of problems in the theory of linear stability of a hot, fully ionized plasma immersed in a strong magnetic field. The most widely used system to magnetically confine a plasma is the tokamak. This is a toroidal, current carrying device with a strong, externally imposed, magnetic field. The author discusses the linear theory of unstable, low-frequency waves in the gradient region, restricted to electrostatic waves. In that case the resulting radial fluxes of particles and energy are due to electric cross-field drifts. In the presence of magnetic fluctuations and small-scale reconnection phenomena, radial transport could also be predominantly along field lines. At present, it is not clear which of the two mechanisms is the dominant feature of the observed anomalous transport. First, the author introduces the theory of drift waves in toroidal geometry. Next, the electrostratic drift modes in toroidal geometry (weakly collisional regime), the equations for low-frequency waves in the strongly collisional regime and the electrostatic drift modes (strongly collisional regime) are discussed. (Auth.)

  14. Metocean input data for drift models applications: Loustic study

    International Nuclear Information System (INIS)

    Michon, P.; Bossart, C.; Cabioc'h, M.

    1995-01-01

    Real-time monitoring and crisis management of oil slicks or floating structures displacement require a good knowledge of local winds, waves and currents used as input data for operational drift models. Fortunately, thanks to world-wide and all-weather coverage, satellite measurements have recently enabled the introduction of new methods for the remote sensing of the marine environment. Within a French joint industry project, a procedure has been developed using basically satellite measurements combined to metocean models in order to provide marine operators' drift models with reliable wind, wave and current analyses and short term forecasts. Particularly, a model now allows the calculation of the drift current, under the joint action of wind and sea-state, thus radically improving the classical laws. This global procedure either directly uses satellite wind and waves measurements (if available on the study area) or indirectly, as calibration of metocean models results which are brought to the oil slick or floating structure location. The operational use of this procedure is reported here with an example of floating structure drift offshore from the Brittany coasts

  15. Radio-tagging technology reveals extreme nest-drifting behavior in a eusocial insect.

    Science.gov (United States)

    Sumner, Seirian; Lucas, Eric; Barker, Jessie; Isaac, Nick

    2007-01-23

    Kin-selection theory underlies our basic understanding of social evolution [1, 2]. Nest drifting in eusocial insects (where workers move between nests) presents a challenge to this paradigm, since a worker should remain as a helper on her natal colony, rather than visit other colonies to which she is less closely related. Here we reveal nest drifting as a strategy by which workers may maximize their indirect fitness by helping on several related nests, preferring those where the marginal return from their help is greatest. By using a novel monitoring technique, radio frequency identification (RFID) tagging, we provide the first accurate estimate of drifting in a eusocial insect: 56% of females drifted in a natural population of the eusocial paper wasp Polistes canadensis, exceeding previous records of drifting in natural populations by more than 30-fold. We demonstrate that drifting cannot be explained through social parasitism, queen succession, mistakes in nest identity, or methodological bias. Instead, workers appear to gain indirect fitness benefits by helping on several related colonies in a viscous population structure. The potential importance of this strategy as a component of the kin-selected benefits for a social insect worker has previously been overlooked because of methodological difficulties in quantifying and studying drifting.

  16. In-Drift Precipitates/Salts Model

    International Nuclear Information System (INIS)

    P. Mariner

    2004-01-01

    This report documents the development and validation of the in-drift precipitates/salts (IDPS) model. The IDPS model is a geochemical model designed to predict the postclosure effects of evaporation and deliquescence on the chemical composition of water within the Engineered Barrier System (EBS) in support of the Total System Performance Assessment for the License Application (TSPA-LA). Application of the model in support of TSPA-LA is documented in ''Engineered Barrier System: Physical and Chemical Environment Model'' (BSC 2004 [DIRS 169860]). Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration (BSC 2004 [DIRS 171156]) is the technical work plan (TWP) for this report. It called for a revision of the previous version of the report (BSC 2004 [DIRS 167734]) to achieve greater transparency, readability, data traceability, and report integration. The intended use of the IDPS model is to estimate and tabulate, within an appropriate level of confidence, the effects of evaporation, deliquescence, and potential environmental conditions on the pH, ionic strength, and chemical compositions of water and minerals on the drip shield or other location within the drift during the postclosure period. Specifically, the intended use is as follows: (1) To estimate, within an appropriate level of confidence, the effects of evaporation and deliquescence on the presence and composition of water occurring within the repository during the postclosure period (i.e., effects on pH, ionic strength, deliquescence relative humidity, total concentrations of dissolved components in the system Na-K-H-Mg-Ca-Al-Cl-F-NO 3 -SO 4 -Br-CO 3 -SiO 2 -CO 2 -O 2 -H 2 O, and concentrations of the following aqueous species that potentially affect acid neutralizing capacity: HCO 3 - , CO 3 2- , OH - , H + , HSO 4 - , Ca 2+ , Mg 2+ , CaHCO 3 + , MgHCO 3 + , HSiO 3 - , and MgOH + ); (2) To estimate, within an appropriate level of confidence, mineral

  17. Mechanical structure of the TOPAZ barrel drift chamber

    International Nuclear Information System (INIS)

    Morimoto, T.; Maruyama, K.; Okuno, H.

    1987-07-01

    A Barrel Drift Chamber (BDC) is constructed for the TOPAZ experiment at TRISTAN, KEK. The BDC has a cylindrical shape with dimensions of 325.2 cm in inner diameter, 347.2 cm in outer diameter and 500 cm long. It consists of 1232 drift tubes made of conductive plastic cathodes, which are staggered in four layers. In this report, a design of the mechanical structure and construction procedures are described in detail. (author)

  18. A Full Front End Chain for Drift Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Chiarello, G. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Corvaglia, A.; Grancagnolo, F. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Panareo, M. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Pepino, A., E-mail: aurora.pepino@le.infn.it [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Università del Salento, Lecce (Italy); Primiceri, P. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Tassielli, G. [Istituto Nazionale di Fisica Nucleare, Lecce (Italy); Fermilab, Batavia, Illinois (United States); Università Marconi, Roma (Italy)

    2014-03-01

    We developed a high performance full chain for drift chamber signals processing. The Front End electronics is a multistage amplifier board based on high performance commercial devices. In addition a fast readout algorithm for Cluster Counting and Timing purposes has been implemented on a Xilinx-Virtex 4 core FPGA. The algorithm analyzes and stores data coming from a Helium based drift tube and represents the outcome of balancing between efficiency and high speed performance.

  19. Investigation of magnetic drift on transport of plasma across magnetic field

    International Nuclear Information System (INIS)

    Hazarika, Parismita; Chakraborty, Monojit; Das, Bidyut; Bandyopadhyay, Mainak

    2015-01-01

    When a metallic body is inserted inside plasma chamber it is always associated with sheath which depends on plasma and wall condition. The effect of sheath formed in the magnetic drift and magnetic field direction on cross field plasma transport has been investigated in a double Plasma device (DPD). The drifts exist inside the chamber in the transverse magnetic field (TMF) region in a direction perpendicular to both magnetic field direction and axis of the DPD chamber. The sheath are formed in the magnetic drift direction in the experimental chamber is due to the insertion of two metallic plates in these directions and in the magnetic field direction sheath is formed at the surface of the TMF channels. These metallic plates are inserted in order to obstruct the magnetic drift so that we can minimised the loss of plasma along drift direction and density in the target region is expected to increase due to the obstruction. It ultimately improves the negative ion formation parameters. The formation of sheath in the transverse magnetic field region is studied by applying electric field both parallel and antiparallel to drift direction. Data are acquired by Langmuir probe in source and target region of our chamber. (author)

  20. Osseointegration of titanium, titanium alloy and zirconia dental implants: current knowledge and open questions.

    Science.gov (United States)

    Bosshardt, Dieter D; Chappuis, Vivianne; Buser, Daniel

    2017-02-01

    Bone healing around dental implants follows the pattern and sequence of intramembraneous osteogenesis with formation of woven bone first of all followed later by formation of parallel-fibered and lamellar bone. Bone apposition onto the implant surface starts earlier in trabecular bone than in compact bone. While the first new bone may be found on the implant surface around 1 week after installation, bone remodeling starts at between 6 and 12 weeks and continues throughout life. Bone remodeling also involves the bone-implant interface, thus transiently exposing portions of the implant surface. Surface modifications creating micro-rough implant surfaces accelerate the osseointegration process of titanium implants, as demonstrated in numerous animal experiments. Sandblasting followed by acid-etching may currently be regarded as the gold standard technique to create micro-rough surfaces. Chemical surface modifications, resulting in higher hydrophilicity, further increase the speed of osseointegration of titanium and titanium-zirconium implants in both animals and humans. Surface modifications of zirconia and alumina-toughened zirconia implants also have an influence on the speed of osseointegration, and some implant types reach high bone-to-implant contact values in animals. Although often discussed independently of each other, surface characteristics, such as topography and chemistry, are virtually inseparable. Contemporary, well-documented implant systems with micro-rough implant surfaces, placed by properly trained and experienced clinicians, demonstrate high long-term survival rates. Nevertheless, implant failures do occur. A low percentage of implants are diagnosed with peri-implantitis after 10 years in function. In addition, a low number of implants seem to be lost for primarily reasons other than biofilm-induced infection. Patient factors, such as medications interfering with the immune system and bone cells, may be an element contributing to continuous bone

  1. Toward biomaterial-based implantable photonic devices

    Directory of Open Access Journals (Sweden)

    Humar Matjaž

    2017-03-01

    Full Text Available Optical technologies are essential for the rapid and efficient delivery of health care to patients. Efforts have begun to implement these technologies in miniature devices that are implantable in patients for continuous or chronic uses. In this review, we discuss guidelines for biomaterials suitable for use in vivo. Basic optical functions such as focusing, reflection, and diffraction have been realized with biopolymers. Biocompatible optical fibers can deliver sensing or therapeutic-inducing light into tissues and enable optical communications with implanted photonic devices. Wirelessly powered, light-emitting diodes (LEDs and miniature lasers made of biocompatible materials may offer new approaches in optical sensing and therapy. Advances in biotechnologies, such as optogenetics, enable more sophisticated photonic devices with a high level of integration with neurological or physiological circuits. With further innovations and translational development, implantable photonic devices offer a pathway to improve health monitoring, diagnostics, and light-activated therapies.

  2. Monitored Drift Chambers in the ATLAS Detector

    CERN Multimedia

    Herten, G

    Monitored Drift Chambers (MDT) are used in the ATLAS Detector to measure the momentum of high energy muons. They consist of drift tubes, which are filled with an Ar-CO2 gas mixture at 3 bar gas pressure. About 1200 drift chambers are required for ATLAS. They are up to 6 m long. Nevertheless the position of every wire needs to be known with a precision of 20 µm within a chamber. In addition, optical alignment sensors are required to measure the relative position of adjacent chambers with a precision of 30µm. This gigantic task seems impossible at first instance. Indeed it took many years of R&D to invent the right tools and methods before the first chamber could be built according to specifications. Today, at the time when 50% of the chambers have been produced, we are confident that the goal for ATLAS can be reached. The mechanical precision of the chambers could be verified with the x-ray tomograph at CERN. This ingenious device, developed for the MDT system, is able to measure the wire position insid...

  3. Hydrogeology and ground-water flow of the drift and Platteville aquifer system, St Louis Park, Minnesota

    Science.gov (United States)

    Lindgren, R.J.

    1995-01-01

    Three aquifers and two confining units have been delineated within the drift underlying the area near the site of a former coal-tar distillation and wood-preserving plant in St. Louis Park, Minnesota. The hydrogeologic units of the drift, in descending order, are the upper drift aquifer, the upper drift confining unit, the middle drift aquifer, the lower drift confining unit. and the lower drift aquifer. A contamination plume consisting of coal-tar derivatives exists in the drift aquifers and in the Platteville aquifer underlying the southern part of the plant site and areas to the south and east of the plant site.

  4. Theory of modulational interaction of trapped ion convective cells and drift wave turbulence

    International Nuclear Information System (INIS)

    Shapiro, V.D.; Diamond, P.H.; Lebedev, V.; Soloviev, G.; Shevchenko, V.

    1993-01-01

    Theoretical and computational studies of the modulational interaction between trapped ion convective cells and short wavelength drift wave turbulence are discussed. These studies are motivated by the fact that cells and drift waves are expected to coexist in tokamaks so that: (a) cells strain and modulate drift waves, and (b) drift waves open-quote ride on close-quote a background of cells. The results of the authors' investigation indicate that: (1) (nonlinear) parametric growth rates of trapped ion convective cells can exceed linear predictions (for drift wave levels at the mixing length limit); (2) a set of coupled envelope equations, akin to the Zakharov equations from Langmuir turbulence, can be derived and used to predict the formation of a dipole pair of convective cells trapped by the drift wave envelope. This dipole pair is strongly anisotropic, due to the structure of the drift wave Reynolds stress which drives the cell flow. Numerical solutions of the envelope equations are in good agreement with theoretical predictions, and indicate the persistence of the structure in time; (3) strong modulation and trapping of drift waves with k perpendicular ρ > 1 occurs. Extensions to magnetically sheared systems and the broader implications of this work as a paradigm for the dynamics of persistent structures in shearing flows are discussed

  5. Method for Providing Semiconductors Having Self-Aligned Ion Implant

    Science.gov (United States)

    Neudeck, Philip G. (Inventor)

    2014-01-01

    A method is disclosed that provides a self-aligned nitrogen-implant particularly suited for a Junction Field Effect Transistor (JFET) semiconductor device preferably comprised of a silicon carbide (SiC). This self-aligned nitrogen-implant allows for the realization of durable and stable electrical functionality of high temperature transistors such as JFETs. The method implements the self-aligned nitrogen-implant having predetermined dimensions, at a particular step in the fabrication process, so that the SiC junction field effect transistors are capable of being electrically operating continuously at 500.degree. C. for over 10,000 hours in an air ambient with less than a 10% change in operational transistor parameters.

  6. ABSTRACTION OF DRIFT SEEPAGE

    International Nuclear Information System (INIS)

    Wilson, Michael L.

    2001-01-01

    Drift seepage refers to flow of liquid water into repository emplacement drifts, where it can potentially contribute to degradation of the engineered systems and release and transport of radionuclides within the drifts. Because of these important effects, seepage into emplacement drifts is listed as a ''principal factor for the postclosure safety case'' in the screening criteria for grading of data in Attachment 1 of AP-3.15Q, Rev. 2, ''Managing Technical Product Inputs''. Abstraction refers to distillation of the essential components of a process model into a form suitable for use in total-system performance assessment (TSPA). Thus, the purpose of this analysis/model is to put the information generated by the seepage process modeling in a form appropriate for use in the TSPA for the Site Recommendation. This report also supports the Unsaturated-Zone Flow and Transport Process Model Report. The scope of the work is discussed below. This analysis/model is governed by the ''Technical Work Plan for Unsaturated Zone Flow and Transport Process Model Report'' (CRWMS MandO 2000a). Details of this activity are in Addendum A of the technical work plan. The original Work Direction and Planning Document is included as Attachment 7 of Addendum A. Note that the Work Direction and Planning Document contains tasks identified for both Performance Assessment Operations (PAO) and Natural Environment Program Operations (NEPO). Only the PAO tasks are documented here. The planning for the NEPO activities is now in Addendum D of the same technical work plan and the work is documented in a separate report (CRWMS MandO 2000b). The Project has been reorganized since the document was written. The responsible organizations in the new structure are the Performance Assessment Department and the Unsaturated Zone Department, respectively. The work plan for the seepage abstraction calls for determining an appropriate abstraction methodology, determining uncertainties in seepage, and providing

  7. Drift in salinity data from Argo profiling floats in the Sea of Japan

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Bajish, C.C.; Behera, S.; Gopalakrishna, V.V.

    In drift analysis of salinity sensors, one major problem is the difficulty in delineating sensor drift from water mass changes. In the present study, a new method is proposed for finding sensor drift that is free from water mass changes...

  8. ATLAS Muon Drift Tube Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Y [KEK, High Energy Accelerator Research Organisation, Tsukuba (Japan); Ball, B; Chapman, J W; Dai, T; Ferretti, C; Gregory, J [University of Michigan, Department of Physics, Ann Arbor, MI (United States); Beretta, M [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Boterenbrood, H; Jansweijer, P P M [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands); Brandenburg, G W; Fries, T; Costa, J Guimaraes da; Harder, S; Huth, J [Harvard University, Laboratory for Particle Physics and Cosmology, Cambridge, MA (United States); Ceradini, F [INFN Roma Tre and Universita Roma Tre, Dipartimento di Fisica, Roma (Italy); Hazen, E [Boston University, Physics Department, Boston, MA (United States); Kirsch, L E [Brandeis University, Department of Physics, Waltham, MA (United States); Koenig, A C [Radboud University Nijmegen/Nikhef, Dept. of Exp. High Energy Physics, Nijmegen (Netherlands); Lanza, A [INFN Pavia, Pavia (Italy); Mikenberg, G [Weizmann Institute of Science, Department of Particle Physics, Rehovot (Israel)], E-mail: brandenburg@physics.harvard.edu (and others)

    2008-09-15

    This paper describes the electronics used for the ATLAS monitored drift tube (MDT) chambers. These chambers are the main component of the precision tracking system in the ATLAS muon spectrometer. The MDT detector system consists of 1,150 chambers containing a total of 354,000 drift tubes. It is capable of measuring the sagitta of muon tracks to an accuracy of 60 {mu}m, which corresponds to a momentum accuracy of about 10% at p{sub T}= 1 TeV. The design and performance of the MDT readout electronics as well as the electronics for controlling, monitoring and powering the detector will be discussed. These electronics have been extensively tested under simulated running conditions and have undergone radiation testing certifying them for more than 10 years of LHC operation. They are now installed on the ATLAS detector and are operating during cosmic ray commissioning runs.

  9. A drift chamber system for a toroidal detector

    International Nuclear Information System (INIS)

    Barbosa, F.J.; Christo, S.; Cuevas, C.; Doolittle, G.; Doughty, D.C.; Hutton, C.; Joyce, D.; Mecking, B.A.; Mestayer, M.D.; Niczyporuk, B.; O'Meara, J.E.; Tilles, D.; Tuzel, W.; Yegneswaran, A.

    1992-01-01

    We present design details for drift chambers to be used in the CLAS detector at CEBAF. Novel features include nonparallel endplates fabricated from composite materials, a gas mixture which includes helium to reduce multiple scattering, low wire tension, and a hexagonal cell layout. Magnetic field strength in the active region ranges from 0 to 2 T, and wire length varies from 10 to 300 cm. We discuss specific construction details for the outer drift chambers. (orig.)

  10. A drift chamber system for a toroidal detector

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, F.J.; Christo, S.; Cuevas, C.; Doolittle, G.; Doughty, D.C.; Hutton, C.; Joyce, D.; Mecking, B.A.; Mestayer, M.D.; Niczyporuk, B.; O' Meara, J.E.; Tilles, D.; Tuzel, W.; Yegneswaran, A. (CEBAF, Newport News, VA (United States))

    1992-12-01

    We present design details for drift chambers to be used in the CLAS detector at CEBAF. Novel features include nonparallel endplates fabricated from composite materials, a gas mixture which includes helium to reduce multiple scattering, low wire tension, and a hexagonal cell layout. Magnetic field strength in the active region ranges from 0 to 2 T, and wire length varies from 10 to 300 cm. We discuss specific construction details for the outer drift chambers. (orig.).

  11. Accurate computer simulation of a drift chamber

    International Nuclear Information System (INIS)

    Killian, T.J.

    1980-01-01

    A general purpose program for drift chamber studies is described. First the capacitance matrix is calculated using a Green's function technique. The matrix is used in a linear-least-squares fit to choose optimal operating voltages. Next the electric field is computed, and given knowledge of gas parameters and magnetic field environment, a family of electron trajectories is determined. These are finally used to make drift distance vs time curves which may be used directly by a track reconstruction program. Results are compared with data obtained from the cylindrical chamber in the Axial Field Magnet experiment at the CERN ISR

  12. Collisional transport across the magnetic field in drift-fluid models

    DEFF Research Database (Denmark)

    Madsen, Jens; Naulin, Volker; Nielsen, Anders Henry

    2016-01-01

    Drift ordered fluid models are widely applied in studies of low-frequency turbulence in the edge and scrape-off layer regions of magnetically confined plasmas. Here, we show how collisional transport across the magnetic field is self-consistently incorporated into drift-fluid models without...

  13. Thermal-wave balancing flow sensor with low-drift power feedback

    NARCIS (Netherlands)

    Dijkstra, Marcel; Lammerink, Theodorus S.J.; Pjetri, O.; de Boer, Meint J.; Berenschot, Johan W.; Wiegerink, Remco J.; Elwenspoek, Michael Curt

    2014-01-01

    A control system using a low-drift power-feedback signal was implemented applying thermal waves, giving a sensor output independent of resistance drift and thermo-electric offset voltages on interface wires. Kelvin-contact sensing and power control is used on heater resistors, thereby inhibiting the

  14. Near-drift thermal analysis including combined modes of conduction, convection, and radiation

    International Nuclear Information System (INIS)

    Ho, C.K.; Francis, N.D.

    1995-01-01

    The performance of waste packages containing high-level nuclear wastes at underground repositories such as the potential repository at Yucca Mountain, Nevada, depends, in part, on the thermodynamic environment immediately surrounding the buried waste packages. For example, degradation of the waste packages can be caused by corrosive and microbial processes, which are influenced by both the relative humidity and temperature within the emplacement drifts. In this paper, the effects of conduction, convection, and radiation are investigated for a heat-generating waste package in an empty-drift. Simulations explicitly modeling radiation from the waste package to the drift wall are compared simulations using only conduction. Temperatures, relative humidities, and vapor mass fractions are compared at various locations within the drift. In addition, the effects of convection on relative humidity and moisture distribution within the drift are presented

  15. Drift wave coherent vortex structures in inhomogeneous plasmas

    International Nuclear Information System (INIS)

    Su, X.N.

    1992-01-01

    Nonlinear drift wave vortex structures in magnetized plasmas are studied theoretically and numerically in the various physical environments. The effects of density and temperature gradients on drift wave vortex dynamics are analyzed using a fully nonlinear model with the Boltzmann density distribution. The equation, based on the full Boltzmann relation, possess no localized monopole solution in the short wavelength (∼ρ s ) region, while in the longer wavelength (∼(ρ s (r) n ) 1/2 ) region the density profile governs the existence of monopole-like solutions. In the longer wavelength regime, however, the monopoles cannot be localized sufficiently to avoid coupling to propagating drift waves due to the inhomogeneity of the plasma. Thus, the monopole vortex is a long lived coherent structure, but it is not precisely a stationary structure since the coupling results in a open-quote flapping close-quote tail. The tail causes energy of the vortex to leak out, but the effect of the temperature gradient is to reduce the leaking of this energy. Nonlinear coherent structures governing by the coupled drift wave-ion acoustic mode equations in sheared magnetic field are studied analytically and numerically. A solitary vortex equation that includes the effects of density and temperature gradients and magnetic shear is derived and analyzed. The results show that for a plasma in a sheared magnetic field, there exist the solitary vortex solutions. The new vortex structures are dipole-like in their symmetry, but not the modon type of dipoles. The numerical simulations are performed in 2-D with the coupled vorticity and parallel mass flow equations. The vortex structures in an unstable drift wave system driven by parallel shear flow are studied. The nonlinear solitary vortex solutions are given and the formation of the vortices from a turbulent state is observed from the numerical simulations

  16. Characteristic parameters of drift chambers calculation; Calculo de los parametros caracteristicos de camaras de deriva

    Energy Technology Data Exchange (ETDEWEB)

    Duran, I; Martinez-Laso, L

    1989-07-01

    We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs.

  17. Preliminary drift design analyses for nuclear waste repository in tuff

    International Nuclear Information System (INIS)

    Hardy, M.P.; Brechtel, C.E.; Goodrich, R.R.; Bauer, S.J.

    1990-01-01

    The Yucca Mountain Project (YMP) is examining the feasibility of siting a repository for high-level nuclear waste at Yucca Mountain, on and adjacent to the Nevada Test Site (NTS). The proposed repository will be excavated in the Topopah Spring Member, which is a moderately fractured, unsaturated, welded tuff. Excavation stability will be required during construction, waste emplacement, retrieval (if required), and closure to ensure worker safety. The subsurface excavations will be subject to stress changes resulting from thermal expansion of the rock mass and seismic events associated with regional tectonic activity and underground nuclear explosions (UNEs). Analyses of drift stability are required to assess the acceptable waste emplacement density, to design the drift shapes and ground support systems, and to establish schedules and cost of construction. This paper outlines the proposed methodology to assess drift stability and then focuses on an example of its application to the YMP repository drifts based on preliminary site data. Because site characterization activities have not begun, the database currently lacks the extensive site-specific field and laboratory data needed to form conclusions as to the final ground support requirements. This drift design methodology will be applied and refined as more site-specific data are generated and as analytical techniques and methodologies are verified during the site characterization process

  18. High resolution drift chambers

    International Nuclear Information System (INIS)

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 μm resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs

  19. Negative Drift in Populations

    DEFF Research Database (Denmark)

    Lehre, Per Kristian

    2011-01-01

    An important step in gaining a better understanding of the stochastic dynamics of evolving populations, is the development of appropriate analytical tools. We present a new drift theorem for populations that allows properties of their long-term behaviour, e.g. the runtime of evolutionary algorithms......, to be derived from simple conditions on the one-step behaviour of their variation operators and selection mechanisms....

  20. The Use of Implants to Improve Removable Partial Denture Function.

    Science.gov (United States)

    Pimentel, Marcele Jardim; Arréllaga, Juan Pablo; Bacchi, Ataís; Del Bel Cury, Altair A

    2014-12-01

    The oral rehabilitation with conventional removable partial dentures in Kennedy class I patients allows continuous bone resorption, dislodgment of the prosthesis during the mastication caused by the resilience of the mucosa, and rotation of the prosthesis. Thus, the associations of distal implants become an attractive modality of treatment for these patients. This case report presented an association of removable partial dentures, milled crowns and osseointegrated implants to rehabilitate a partial edentulous patient. A removable partial denture associated with implants and metal-ceramic milled crowns can offer excellent esthetics, and will improve function and biomechanics, at a reduced cost.

  1. Electromagnetic nonlinear gyrokinetics with polarization drift

    International Nuclear Information System (INIS)

    Duthoit, F.-X.; Hahm, T. S.; Wang, Lu

    2014-01-01

    A set of new nonlinear electromagnetic gyrokinetic Vlasov equation with polarization drift and gyrokinetic Maxwell equations is systematically derived by using the Lie-transform perturbation method in toroidal geometry. For the first time, we recover the drift-kinetic expression for parallel acceleration [R. M. Kulsrud, in Basic Plasma Physics, edited by A. A. Galeev and R. N. Sudan (North-Holland, Amsterdam, 1983)] from the nonlinear gyrokinetic equations, thereby bridging a gap between the two formulations. This formalism should be useful in addressing nonlinear ion Compton scattering of intermediate-mode-number toroidal Alfvén eigenmodes for which the polarization current nonlinearity [T. S. Hahm and L. Chen, Phys. Rev. Lett. 74, 266 (1995)] and the usual finite Larmor radius effects should compete

  2. Bottle appeal drifts across the Pacific

    Science.gov (United States)

    Ebbesmeyer, Curtis; Ingraham, W. James, Jr.; McKinnon, Richard; Okubo, Akira; Wang, Dong-Ping; Strickland, Richard; Willing, Peter

    Pacific drift currents were used by a group of oceanographers to estimate the path of a drift bottle that was found on a beach of Barkley Sound in Vancouver Island by Richard Strickland on June 10, 1990. The Chinese rice wine bottle, which remained unopened until December 18, 1991, contained six leaflets, one appealing for the release of China's well-known dissident, Wei Jingsheng. The bottle was one of thousands set adrift as part of a propaganda effort from the islands of Quemoy and Matsu off mainland China shortly after Wei was sentenced in 1979 to 15 years in prison (see Figure 1 for locations). Wei was in poor health and still in prison when the bottle made its way across the Pacific Ocean.

  3. Short dental implants: an emerging concept in implant treatment.

    Science.gov (United States)

    Al-Hashedi, Ashwaq Ali; Taiyeb Ali, Tara Bai; Yunus, Norsiah

    2014-06-01

    Short implants have been advocated as a treatment option in many clinical situations where the use of conventional implants is limited. This review outlines the effectiveness and clinical outcomes of using short implants as a valid treatment option in the rehabilitation of edentulous atrophic alveolar ridges. Initially, an electronic search was performed on the following databases: Medline, PubMed, Embase, Cochrane Database of Systematic Reviews, and DARE using key words from January 1990 until May 2012. An additional hand search was included for the relevant articles in the following journals: International Journal of Oral and Maxillofacial Implants, Clinical Oral Implants Research, Journal of Clinical Periodontology, International Journal of Periodontics, Journal of Periodontology, and Clinical Implant Dentistry and Related Research. Any relevant papers from the journals' references were hand searched. Articles were included if they provided detailed data on implant length, reported survival rates, mentioned measures for implant failure, were in the English language, involved human subjects, and researched implants inserted in healed atrophic ridges with a follow-up period of at least 1 year after implant-prosthesis loading. Short implants demonstrated a high rate of success in the replacement of missing teeth in especially atrophic alveolar ridges. The advanced technology and improvement of the implant surfaces have encouraged the success of short implants to a comparable level to that of standard implants. However, further randomized controlled clinical trials and prospective studies with longer follow-up periods are needed.

  4. Drift-Diffusion Equation

    Directory of Open Access Journals (Sweden)

    K. Banoo

    1998-01-01

    equation in the discrete momentum space. This is shown to be similar to the conventional drift-diffusion equation except that it is a more rigorous solution to the Boltzmann equation because the current and carrier densities are resolved into M×1 vectors, where M is the number of modes in the discrete momentum space. The mobility and diffusion coefficient become M×M matrices which connect the M momentum space modes. This approach is demonstrated by simulating electron transport in bulk silicon.

  5. Geomorphology and drift potential of major aeolian sand deposits in Egypt

    Science.gov (United States)

    Hereher, Mohamed E.

    2018-03-01

    Aeolian sand deposits cover a significant area of the Egyptian deserts. They are mostly found in the Western Desert and Northern Sinai. In order to understand the distribution, pattern and forms of sand dunes in these dune fields it is crucial to analyze the wind regimes throughout the sandy deserts of the country. Therefore, a set of wind data acquired from twelve meteorological stations were processed in order to determine the drift potential (DP), the resultant drift potential (RDP) and the resultant drift direction (RDD) of sand in each dune field. The study showed that the significant aeolian sand deposits occur in low-energy wind environments with the dominance of linear and transverse dunes. Regions of high-energy wind environments occur in the south of the country and exhibit evidence of deflation rather than accumulation with the occurrence of migratory crescentic dunes. Analysis of the sand drift potentials and their directions help us to interpret the formation of major sand seas in Egypt. The pattern of sand drift potential/direction suggests that the sands in these seas might be inherited from exogenous sources.

  6. Do insect repellents induce drift behaviour in aquatic non-target organisms?

    Science.gov (United States)

    Fink, Patrick; Moelzner, Jana; Berghahn, Ruediger; von Elert, Eric

    2017-01-01

    Synthetic insect repellents are compounds applied to surfaces to discourage insects, mainly mosquitoes, from landing on those surfaces. As some of these repellents have repeatedly been detected in surface waters at significant concentrations, they may also exert repellent effects on aquatic non-target organisms. In running water systems, aquatic invertebrates actively enter downstream drift in order to avoid unfavourable environmental conditions. We thus tested the hypothesis that the widely used insect repellents DEET (N,N-Diethyl-m-toluamide), EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester) and Icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropyl ester) induce downstream drift behaviour in the aquatic invertebrates Gammarus pulex (Crustacea, Amphipoda) and Cloeon dipterum (Insecta, Ephemeroptera), using a laboratory-scale drift assay. We found no clear increase in the drift behaviour of both invertebrate species across a concentration gradient of eight orders of magnitude and even beyond maximum environmental concentrations for any of the three repellents. We found no evidence for a direct drift-inducing activity of insect repellents on aquatic non-target organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Drift Wave Test Particle Transport in Reversed Shear Profile

    International Nuclear Information System (INIS)

    Horton, W.; Park, H.B.; Kwon, J.M.; Stronzzi, D.; Morrison, P.J.; Choi, D.I.

    1998-01-01

    Drift wave maps, area preserving maps that describe the motion of charged particles in drift waves, are derived. The maps allow the integration of particle orbits on the long time scale needed to describe transport. Calculations using the drift wave maps show that dramatic improvement in the particle confinement, in the presence of a given level and spectrum of E x B turbulence, can occur for q(r)-profiles with reversed shear. A similar reduction in the transport, i.e. one that is independent of the turbulence, is observed in the presence of an equilibrium radial electric field with shear. The transport reduction, caused by the combined effects of radial electric field shear and both monotonic and reversed shear magnetic q-profiles, is also investigated

  8. Detection and estimation of sensor drifts using Kalman filters with a demonstration on a pressurizer

    International Nuclear Information System (INIS)

    Cho, Sungwhan; Jiang, Jin

    2012-01-01

    Highlights: ► How the expectation of the innovations changes in the drift case is formulated. ► Using the divergence in the expectation for detection of the drift is demonstrated. ► An augmented system model is proposed for estimation of the drift. ► Demonstration of the proposed algorithm is presented using a pressurizer model. - Abstract: An algorithm for detection and estimation of sensor drifts is proposed in this paper. The algorithm is based on estimation of the process states from which the measurements are made and the rate of drifts using a state augmented Kalman filter. The detection and the estimation of a drift are carried out by evaluating the mean of the innovation sequence of the Kalman filter. The relationship between the mean and the drift is analyzed in detail to provide insights on the connection between the innovation sequence and the drift. The developed algorithm has been successfully applied to a pressurizer for detection and estimation of pressure sensor drifts. The results convincingly demonstrate the capability of the algorithm.

  9. The properties of the cylindrical drift chambers of the CELLO detector

    International Nuclear Information System (INIS)

    Binder, U.

    1983-12-01

    In the present thesis the study of the properties of the cylindrical drift chamber of the CELLO interior detector by muons from the cosmic radiation is described. An iterative procedure for the parametrization of the timepath relation is presented. The numerical approximation obtained by means of this procedure deviated in all ranges of drift time by less than 50 μm from the experimentally determined, nonlinear time-path relation. The chamber properties were determined with and without magnetic fields: With an argon-ethane 50%/50% gas mixture a long plateau of the detection probabilities was reached. Without magnetic field by the drift chambers a mean spatial resolution of 170 μm was obtained. From the dependence of the spatial resolution from the drift path results that the drift chambers respond if the electrons from the first 2 to 3 primary ionizations reach the signal wire. The mean response probability of the drift chambers contributes to 97.5% and the overresponse probability to 3.6%. The mean spatial resolution in the magnetic field was determined by means of the chi 2 -distribution, it contributes to 170 μm. For the response probability the value of 98.3% was determined. The errors in the track parameters were determined by comparison of the cosmic ray tracks in the upper and lower half of the detector. (orig./HSI) [de

  10. Tillage techniques to reactivate aeolian erosion on inland drift-sand

    NARCIS (Netherlands)

    Riksen, M.J.P.M.; Goossens, D.

    2005-01-01

    The inland drift-sand areas in northern Europe are characterised by a rapid decline in both aeolian activity and areal size. Many former drift-sand surfaces have become immobilised by natural or man-induced processes, such as conversion into forest or other terrain for agricultural, economic or

  11. A Fast Faraday Cup for the Neutralized Drift Compression Experiment

    CERN Document Server

    Sefkow, Adam; Coleman, Joshua E; Davidson, Ronald C; Efthimion, Philip; Eylon, Shmuel; Gilson, Erik P; Greenway, Wayne; Henestroza, Enrique; Kwan, Joe W; Roy, Prabir K; Vanecek, David; Waldron, William; Welch, Dale; Yu, Simon

    2005-01-01

    Heavy ion drivers for high energy density physics applications and inertial fusion energy use space-charge-dominated beams which require longitudinal bunch compression in order to achieve sufficiently high beam intensity at the target. The Neutralized Drift Compression Experiment-1A (NDCX-1A) at Lawrence Berkeley National Laboratory (LBNL) is used to determine the effective limits of neutralized drift compression. NDCX-1A investigates the physics of longitudinal drift compression of an intense ion beam, achieved by imposing an initial velocity tilt on the drifting beam and neutralizing the beam's space-charge with background plasma. Accurately measuring the longitudinal compression of the beam pulse with high resolution is critical for NDCX-1A, and an understanding of the accessible parameter space is modeled using the LSP particle-in-cell (PIC) code. The design and preliminary experimental results for an ion beam probe which measures the total beam current at the focal plane as a function of time are summari...

  12. Drift-flux parameters for upward gas flow in stagnant liquid

    International Nuclear Information System (INIS)

    Kataoka, Yoshiyuki; Suzuki, Hiroaki; Murase, Michio

    1987-01-01

    The drift-flux model is widely used for gas-liquid two phase flow analysis, because it is applicable to various flow patterns and a wide range of void fractions. The drift-flux parameters for upward gas flow in stagnant liquid, however, have not been well examined. In this study, the distribution parameter C o and the drift velocity V gj for stagnant liquid were derived from the void fraction correlation and boundary conditions of drift-flux parameters, and then compared with C o and V gj for high liquid velocities. Also using the two region model where a circular flow area was divided into an inner region of cocurrent up-flow and an outer annulus region of liquid down flow, C o and V gj for stagnant liquid and for high liquid velocity were compared. The results showed that C o values for stagnant liquid were larger than values for high liquid velocity, while V gj values were almost the same for both cases. (author)

  13. Quantum-corrected drift-diffusion models for transport in semiconductor devices

    International Nuclear Information System (INIS)

    De Falco, Carlo; Gatti, Emilio; Lacaita, Andrea L.; Sacco, Riccardo

    2005-01-01

    In this paper, we propose a unified framework for Quantum-corrected drift-diffusion (QCDD) models in nanoscale semiconductor device simulation. QCDD models are presented as a suitable generalization of the classical drift-diffusion (DD) system, each particular model being identified by the constitutive relation for the quantum-correction to the electric potential. We examine two special, and relevant, examples of QCDD models; the first one is the modified DD model named Schroedinger-Poisson-drift-diffusion, and the second one is the quantum-drift-diffusion (QDD) model. For the decoupled solution of the two models, we introduce a functional iteration technique that extends the classical Gummel algorithm widely used in the iterative solution of the DD system. We discuss the finite element discretization of the various differential subsystems, with special emphasis on their stability properties, and illustrate the performance of the proposed algorithms and models on the numerical simulation of nanoscale devices in two spatial dimensions

  14. Friction coefficient and effective interference at the implant-bone interface.

    Science.gov (United States)

    Damm, Niklas B; Morlock, Michael M; Bishop, Nicholas E

    2015-09-18

    Although the contact pressure increases during implantation of a wedge-shaped implant, friction coefficients tend to be measured under constant contact pressure, as endorsed in standard procedures. Abrasion and plastic deformation of the bone during implantation are rarely reported, although they define the effective interference, by reducing the nominal interference between implant and bone cavity. In this study radial forces were analysed during simulated implantation and explantation of angled porous and polished implant surfaces against trabecular bone specimens, to determine the corresponding friction coefficients. Permanent deformation was also analysed to determine the effective interference after implantation. For the most porous surface tested, the friction coefficient initially increased with increasing normal contact stress during implantation and then decreased at higher contact stresses. For a less porous surface, the friction coefficient increased continually with normal contact stress during implantation but did not reach the peak magnitude measured for the rougher surface. Friction coefficients for the polished surface were independent of normal contact stress and much lower than for the porous surfaces. Friction coefficients were slightly lower for pull-out than for push-in for the porous surfaces but not for the polished surface. The effective interference was as little as 30% of the nominal interference for the porous surfaces. The determined variation in friction coefficient with radial contact force, as well as the loss of interference during implantation will enable a more accurate representation of implant press-fitting for simulations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Number of implants for mandibular implant overdentures: a systematic review

    Science.gov (United States)

    Lee, Jeong-Yol; Kim, Ha-Young; Bryant, S. Ross

    2012-01-01

    PURPOSE The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction. MATERIALS AND METHODS A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants. RESULTS Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants. CONCLUSION The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants. PMID:23236572

  16. Development of Fast High-Resolution Muon Drift-Tube Detectors for High Counting Rates

    CERN Document Server

    INSPIRE-00287945; Dubbert, J.; Horvat, S.; Kortner, O.; Kroha, H.; Legger, F.; Richter, R.; Adomeit, S.; Biebel, O.; Engl, A.; Hertenberger, R.; Rauscher, F.; Zibell, A.

    2011-01-01

    Pressurized drift-tube chambers are e?cient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 micons and almost 100% tracking e?ciency with 6 layers of 30 mm diameter drift tubes operated with Ar:CO2 (93:7) gas mixture at 3 bar and a gas gain of 20000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and gamma-rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities larger than the design value of 10-34 per square cm and second. Decreasing the drift-tube diameter to 15 mm while keeping the other parameters, including the gas gain, unchanged reduces the maximum drift time from about 700 ns to 200 ns and the drift-tube occupancy by a factor of 7. New drift-tube chambers for the endcap regions of the ATLAS muon spectrometer have been designed. A prototype chamber consisting of 12 times 8 l...

  17. Exacerbation of electrical storm subsequent to implantation of a right vagal stimulator.

    Science.gov (United States)

    Shalaby, Alaa A; El-Saed, Aiman; Nemec, Jan; Moossy, John J; Balzer, Jeffrey R

    2007-12-01

    A patient with advanced ischemic cardiomyopathy underwent implantation of a vagal stimulator in an attempt to control recurrent drug refractory ventricular arrhythmia. Electrical storm was exacerbated after the implant and continued after neurostimulation was discontinued. The report aims to provide a cautionary note to application of vagal stimulation for control of cardiac arrhythmia.

  18. Algorithm for statistical noise reduction in three-dimensional ion implant simulations

    International Nuclear Information System (INIS)

    Hernandez-Mangas, J.M.; Arias, J.; Jaraiz, M.; Bailon, L.; Barbolla, J.

    2001-01-01

    As integrated circuit devices scale into the deep sub-micron regime, ion implantation will continue to be the primary means of introducing dopant atoms into silicon. Different types of impurity profiles such as ultra-shallow profiles and retrograde profiles are necessary for deep submicron devices in order to realize the desired device performance. A new algorithm to reduce the statistical noise in three-dimensional ion implant simulations both in the lateral and shallow/deep regions of the profile is presented. The computational effort in BCA Monte Carlo ion implant simulation is also reduced

  19. [Study of spectrum drifting of primary colors and its impact on color rendering properties].

    Science.gov (United States)

    Cui, Xiao-yan; Zhang, Xiao-dong

    2012-08-01

    LEDs are currently used widely to display text, graphics and images in large screens. With red, green and blue LEDs as three primary colors, color rendition will be realized through color mixing. However, LEDs' spectrum will produce drifts with the changes in the temperature environment. With the changes in the driving current simulating changes in the temperature, the three primary color LEDs' spectral drifts were tested, and the drift characteristics of the three primary colors were obtained respectively. Based on the typical characteristics of the LEDs and the differences between LEDs with different colors in composition and molecular structure, the paper analyzed the reason for the spectrum drifts and the drift characteristics of different color LEDs, and proposed the equations of spectrum drifts. Putting the experimental data into the spectrum drift equations, the paper analyzed the impacts of primary colors on the mixed color, pointed out a way to reduce the chromatic aberration, and provided the theory for engineering application of color LEDs.

  20. Drift chamber tracking with a VLSI neural network

    International Nuclear Information System (INIS)

    Lindsey, C.S.; Denby, B.; Haggerty, H.; Johns, K.

    1992-10-01

    We have tested a commercial analog VLSI neural network chip for finding in real time the intercept and slope of charged particles traversing a drift chamber. Voltages proportional to the drift times were input to the Intel ETANN chip and the outputs were recorded and later compared off line to conventional track fits. We will discuss the chamber and test setup, the chip specifications, and results of recent tests. We'll briefly discuss possible applications in high energy physics detector triggers

  1. Measurements of electron drift velocity in pure isobutane

    Energy Technology Data Exchange (ETDEWEB)

    Vivaldini, Tulio C.; Lima, Iara B.; Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B., E-mail: ccbueno@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ridenti, Marco A.; Pascholati, Paulo R. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear; Fonte, Paulo; Mangiarotti, Alessio [Universidade de Coimbra (Portugal). Dept de Fisica. Lab. de Instrumentacao e Fisica Experimental de Particulas

    2009-07-01

    In this work we report on preliminary results related to the dependence of the electron drift velocity for pure isobutane as a function of reduced electric field (E/N) in the range from 100 Td up to 216 Td. The measurements of electron drift velocity were based on the Pulsed Townsend technique. In order to validate the technique and analyzing non-uniformity effects, results for nitrogen are also presented and compared with a numerical simulation of the Bolsig+ code. (author)

  2. Measurements of electron drift velocity in pure isobutane

    International Nuclear Information System (INIS)

    Vivaldini, Tulio C.; Lima, Iara B.; Goncalves, Josemary A.C.; Botelho, Suzana; Tobias, Carmen C.B.; Ridenti, Marco A.; Pascholati, Paulo R.; Fonte, Paulo; Mangiarotti, Alessio

    2009-01-01

    In this work we report on preliminary results related to the dependence of the electron drift velocity for pure isobutane as a function of reduced electric field (E/N) in the range from 100 Td up to 216 Td. The measurements of electron drift velocity were based on the Pulsed Townsend technique. In order to validate the technique and analyzing non-uniformity effects, results for nitrogen are also presented and compared with a numerical simulation of the Bolsig+ code. (author)

  3. Power Approaches for Implantable Medical Devices

    Directory of Open Access Journals (Sweden)

    Achraf Ben Amar

    2015-11-01

    Full Text Available Implantable medical devices have been implemented to provide treatment and to assess in vivo physiological information in humans as well as animal models for medical diagnosis and prognosis, therapeutic applications and biological science studies. The advances of micro/nanotechnology dovetailed with novel biomaterials have further enhanced biocompatibility, sensitivity, longevity and reliability in newly-emerged low-cost and compact devices. Close-loop systems with both sensing and treatment functions have also been developed to provide point-of-care and personalized medicine. Nevertheless, one of the remaining challenges is whether power can be supplied sufficiently and continuously for the operation of the entire system. This issue is becoming more and more critical to the increasing need of power for wireless communication in implanted devices towards the future healthcare infrastructure, namely mobile health (m-Health. In this review paper, methodologies to transfer and harvest energy in implantable medical devices are introduced and discussed to highlight the uses and significances of various potential power sources.

  4. Drift Correction of Lightweight Microbolometer Thermal Sensors On-Board Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Mesas-Carrascosa

    2018-04-01

    Full Text Available The development of lightweight sensors compatible with mini unmanned aerial vehicles (UAVs has expanded the agronomical applications of remote sensing. Of particular interest in this paper are thermal sensors based on lightweight microbolometer technology. These are mainly used to assess crop water stress with thermal images where an accuracy greater than 1 °C is necessary. However, these sensors lack precise temperature control, resulting in thermal drift during image acquisition that requires correction. Currently, there are several strategies to manage thermal drift effect. However, these strategies reduce useful flight time over crops due to the additional in-flight calibration operations. This study presents a drift correction methodology for microbolometer sensors based on redundant information from multiple overlapping images. An empirical study was performed in an orchard of high-density hedgerow olive trees with flights at different times of the day. Six mathematical drift correction models were developed and assessed to explain and correct drift effect on thermal images. Using the proposed methodology, the resulting thermally corrected orthomosaics yielded a rate of error lower than 1° C compared to those where no drift correction was applied.

  5. Drift study of SU8 cantilevers in liquid and gaseous environments.

    Science.gov (United States)

    Tenje, Maria; Keller, Stephan; Dohn, Søren; Davis, Zachary J; Boisen, Anja

    2010-05-01

    We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum.

  6. Drift study of SU8 cantilevers in liquid and gaseous environments

    DEFF Research Database (Denmark)

    Tenje, Maria; Keller, Stephan Sylvest; Dohn, Søren

    2010-01-01

    We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1 mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe...... coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum....... this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we...

  7. Concentrated Hitting Times of Randomized Search Heuristics with Variable Drift

    DEFF Research Database (Denmark)

    Lehre, Per Kristian; Witt, Carsten

    2014-01-01

    Drift analysis is one of the state-of-the-art techniques for the runtime analysis of randomized search heuristics (RSHs) such as evolutionary algorithms (EAs), simulated annealing etc. The vast majority of existing drift theorems yield bounds on the expected value of the hitting time for a target...

  8. Primary prevention of peri-implantitis: managing peri-implant mucositis.

    Science.gov (United States)

    Jepsen, Søren; Berglundh, Tord; Genco, Robert; Aass, Anne Merete; Demirel, Korkud; Derks, Jan; Figuero, Elena; Giovannoli, Jean Louis; Goldstein, Moshe; Lambert, France; Ortiz-Vigon, Alberto; Polyzois, Ioannis; Salvi, Giovanni E; Schwarz, Frank; Serino, Giovanni; Tomasi, Cristiano; Zitzmann, Nicola U

    2015-04-01

    Over the past decades, the placement of dental implants has become a routine procedure in the oral rehabilitation of fully and partially edentulous patients. However, the number of patients/implants affected by peri-implant diseases is increasing. As there are--in contrast to periodontitis--at present no established and predictable concepts for the treatment of peri-implantitis, primary prevention is of key importance. The management of peri-implant mucositis is considered as a preventive measure for the onset of peri-implantitis. Therefore, the remit of this working group was to assess the prevalence of peri-implant diseases, as well as risks for peri-implant mucositis and to evaluate measures for the management of peri-implant mucositis. Discussions were informed by four systematic reviews on the current epidemiology of peri-implant diseases, on potential risks contributing to the development of peri-implant mucositis, and on the effect of patient and of professionally administered measures to manage peri-implant mucositis. This consensus report is based on the outcomes of these systematic reviews and on the expert opinion of the participants. Key findings included: (i) meta-analysis estimated a weighted mean prevalence for peri-implant mucositis of 43% (CI: 32-54%) and for peri-implantitis of 22% (CI: 14-30%); (ii) bleeding on probing is considered as key clinical measure to distinguish between peri-implant health and disease; (iii) lack of regular supportive therapy in patients with peri-implant mucositis was associated with increased risk for onset of peri-implantitis; (iv) whereas plaque accumulation has been established as aetiological factor, smoking was identified as modifiable patient-related and excess cement as local risk indicator for the development of peri-implant mucositis; (v) patient-administered mechanical plaque control (with manual or powered toothbrushes) has been shown to be an effective preventive measure; (vi) professional intervention

  9. Simulation of heat transfer around a canister placed horizontally in a drift

    International Nuclear Information System (INIS)

    Moujaes, S.; Bhargava, A.

    1994-01-01

    The Yucca Mountain Site Characterization Project is investigating the feasibility of locating a high level radioactive nuclear waste repository at Yucca Mountain, Nevada. The bore hole and the in-drift waste emplacement schemes are under evaluation as potential repository drift geometries. This paper presents a two-dimensional finite element thermal analysis of the nuclear waste canister placed horizontally in a drift. Simulation has been carried out for 1000 years and the peak temperatures at the walls of the drift and at the center of the canister have been determined. The effect of the three modes of heat transfer, conduction, natural convection and radiation, is also discussed

  10. Proximal thoracic aorta dimensions after continuous-flow left ventricular assist device implantation: Longitudinal changes and relation to aortic valve insufficiency.

    Science.gov (United States)

    Fine, Nowell M; Park, Soon J; Stulak, John M; Topilsky, Yan; Daly, Richard C; Joyce, Lyle D; Pereira, Naveen L; Schirger, John A; Edwards, Brooks S; Lin, Grace; Kushwaha, Sudhir S

    2016-04-01

    In this study we examined the impact of continuous-flow left ventricular assist device (CF-LVAD) support on proximal thoracic aorta dimensions. Aortic root and ascending aorta diameter were measured from serial echocardiograms before and after CF-LVAD implantation in patients with ≥6 months of support, and correlated with the development of >mild aortic valve insufficiency (AI). Of 162 patients included, mean age was 58 ± 11 years and 128 (79%) were male. Seventy-nine (63%) were destination therapy patients. Mean aortic root and ascending aorta diameters at baseline, 1 month, 6 months, 12 months and long-term follow-up (mean 2.0 ± 1.4 years) were 3.5 ± 0.4, 3.5 ± 0.3, 3.9 ± 0.3, 3.9 ± 0.2 and 4.0 ± 0.3, and 3.3 ± 0.2, 3.3 ± 0.3, 3.6 ± 0.2, 3.6 ± 0.3 and 3.6 ± 0.3 cm, respectively. Only change in aortic root diameter from 1-month to 6-month follow-up reached statistical significance (p = 0.03). Nine (6%) patients had accelerated proximal thoracic aorta expansion (>0.5 cm/year), occurring predominantly in the first 6 months after implantation. These patients were older and more likely to have hypertension and baseline proximal thoracic aorta dilation. Forty-five (28%) patients developed >mild AI at long-term follow-up, including 7 of 9 (78%) of those with accelerated proximal thoracic aorta expansion. All 7 had aortic valves that remained closed throughout the cardiac cycle, and this, along with duration of CF-LVAD support and increase in aortic root diameter, were significantly associated with developing >mild AI. CF-LVAD patients have small increases in proximal thoracic aorta dimensions that predominantly occur within the first 6 months after implantation and then stabilize. Increasing aortic root diameter was associated with AI development. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  11. Driving safety among patients with automatic implantable cardioverter defibrillators.

    Science.gov (United States)

    Finch, N J; Leman, R B; Kratz, J M; Gillette, P C

    1993-10-06

    To determine the driving behavior of patients following the placement of automatic implantable cardioverter defibrillators (AICDs). Forty patients with AICDs (33 men, seven women; mean age, 62.7 years) responded to a questionnaire designed to ascertain driving behavior after hospital discharge. Despite medical advice never to drive again, 28 patients (70%) resumed driving, with the majority doing so by 8 months after AICD implantation. Of these, 11 (40%) identified themselves as the primary driver in their household. Fourteen (50%) drove daily. Two (7%) were driving and continued to drive during discharge of their AICDs. Twenty-five (91%) reported that they felt comfortable and safe while driving. A majority of patients with AICDs continue to drive after a proscription of this activity by health care workers.

  12. Cap Bubble Drift Velocity in a Confined Test Section

    International Nuclear Information System (INIS)

    Xiaodong Sun; Seungjin Kim; Mamoru Ishii; Lincoln, Frank W.; Beus, Stephen G.

    2002-01-01

    In the two-group interfacial area transport equation, bubbles are categorized into two groups, i.e., spherical/distorted bubbles as group 1 and cap/slug/churn-turbulent bubbles as group 2. The bubble rise velocities for both groups of bubbles may be estimated by the drift flux model by applying different distribution parameters and drift velocities for both groups. However, the drift velocity for group 2 bubbles is not always applicable (when the wall effect becomes important) as in the current test loop of interest where the flow channel is confined by two parallel flat walls, with a dimension of 200-mm in width and 10-mm in gap. The previous experiments indicated that no stable slug flow existed in this test section, which was designed to permit visualization of the flow patterns and bubble characteristics without the distortion associated with curved surfaces. In fact, distorted cap bubbly and churn-turbulent flow was observed. Therefore, it is essential to developed a correlation for cap bubble drift velocity in this confined flow channel. Since the rise velocity of a cap bubble depends on its size, a high-speed movie camera is used to capture images of cap bubbles to obtain the bubble size information. Meanwhile, the rise velocity of cap and elongated bubbles (called cap bubbles hereafter) is investigated by examining the captured images frame by frame. As a result, the conventional correlation of drift velocity for slug bubbles is modified and acceptable agreements between the measurements and correlation estimation are achieved

  13. Thirty-five years of drift-tube linac experience

    International Nuclear Information System (INIS)

    Knowles, H.B.

    1984-10-01

    The history of the drift-tube linear accelerator (linac) for the first 35 years of its existence is briefly reviewed. Both US and foreign experience is included. Particular attention is given to technological improvements, operational reliability, capital investment, and number of personnel committed to drift-tube linac (DTL) development. Preliminary data indicate that second- and third-generation (post-1960) DTLs have, in the US alone, operated for a combined total period of more than 75 machine-years and that very high reliability (>90%) has been achieved. Existing US drift-tube linacs represent a capital investment of at least $250 million (1983). Additional statistical evidence, derived from the proceedings of the last 11 linear accelerator conferences, supports the view that the DTL has achieved a mature technological base. The report concludes with a discussion of important recent advances in technology and their applications to the fourth generation of DTLs, many of which are now becoming operational

  14. Image processing for drift compensation in fluorescence microscopy

    DEFF Research Database (Denmark)

    Petersen, Steffen; Thiagarajan, Viruthachalam; Coutinho, Isabel

    2013-01-01

    Fluorescence microscopy is characterized by low background noise, thus a fluorescent object appears as an area of high signal/noise. Thermal gradients may result in apparent motion of the object, leading to a blurred image. Here, we have developed an image processing methodology that may remove....../reduce blur significantly for any type of microscopy. A total of ~100 images were acquired with a pixel size of 30 nm. The acquisition time for each image was approximately 1second. We can quantity the drift in X and Y using the sub pixel accuracy computed centroid location of an image object in each frame....... We can measure drifts down to approximately 10 nm in size and a drift-compensated image can therefore be reconstructed on a grid of the same size using the “Shift and Add” approach leading to an image of identical size asthe individual image. We have also reconstructed the image using a 3 fold larger...

  15. Het effect van spuitboombeweging en windvector op de drift : Randvariatie metingen 2007-2008

    NARCIS (Netherlands)

    Groot, T.T.; Stallinga, H.; Michielsen, J.G.P.; Velde, van P.; Zande, van de J.C.

    2014-01-01

    Spray drift measurements have been performed to quantify the effect of variations in wind angle and wind speed during application and the sprayer boom movement alongside the sprayed edge of the field on spray drift deposition alongside a sprayed potato field (2007-2008). Results of these spray drift

  16. Ground Control for Emplacement Drifts for SR

    International Nuclear Information System (INIS)

    Y. Sun

    2000-01-01

    This analysis demonstrates that a satisfactory ground control system can be designed for the Yucca Mountain site, and provides the technical basis for the design of ground support systems to be used in repository emplacement and non-emplacement drifts. The repository ground support design was based on analytical methods using acquired computer codes, and focused on the final support systems. A literature review of case histories, including the lessons learned from the design and construction of the ESF, the studies on the seismic damages of underground openings, and the use of rock mass classification systems in the ground support design, was conducted (Sections 6.3.4 and 6.4). This review provided some basis for determining the inputs and methodologies used in this analysis. Stability of the supported and unsupported emplacement and non-emplacement drifts was evaluated in this analysis. The excavation effects (i.e., state of the stress change due to excavation), thermal effects (i.e., due to heat output from waste packages), and seismic effects (i.e., from potential earthquake events) were evaluated, and stress controlled modes of failure were examined for two in situ stress conditions (k 0 =0.3 and 1.0) using rock properties representing rock mass categories of 1 and 5. Variation of rock mass units such as the non-lithophysal (Tptpmn) and lithophysal (Tptpll) was considered in the analysis. The focus was on the non-lithophysal unit because this unit appears to be relatively weaker and has much smaller joint spacing. Therefore, the drift stability and ground support needs were considered to be controlled by the design for this rock unit. The ground support systems for both emplacement and non-emplacement drifts were incorporated into the models to assess their performance under in situ, thermal, and seismic loading conditions. Both continuum and discontinuum modeling approaches were employed in the analyses of the rock mass behavior and in the evaluation of the

  17. SYSTEMS SAFETY ANALYSIS FOR FIRE EVENTS ASSOCIATED WITH THE ECRB CROSS DRIFT

    International Nuclear Information System (INIS)

    R. J. Garrett

    2001-01-01

    The purpose of this analysis is to systematically identify and evaluate fire hazards related to the Yucca Mountain Site Characterization Project (YMP) Enhanced Characterization of the Repository Block (ECRB) East-West Cross Drift (commonly referred to as the ECRB Cross-Drift). This analysis builds upon prior Exploratory Studies Facility (ESF) System Safety Analyses and incorporates Topopah Springs (TS) Main Drift fire scenarios and ECRB Cross-Drift fire scenarios. Accident scenarios involving the fires in the Main Drift and the ECRB Cross-Drift were previously evaluated in ''Topopah Springs Main Drift System Safety Analysis'' (CRWMS M and O 1995) and the ''Yucca Mountain Site Characterization Project East-West Drift System Safety Analysis'' (CRWMS M and O 1998). In addition to listing required mitigation/control features, this analysis identifies the potential need for procedures and training as part of defense-in-depth mitigation/control features. The inclusion of this information in the System Safety Analysis (SSA) is intended to assist the organization(s) (e.g., Construction, Environmental Safety and Health, Design) responsible for these aspects of the ECRB Cross-Drift in developing mitigation/control features for fire events, including Emergency Refuge Station(s). This SSA was prepared, in part, in response to Condition/Issue Identification and Reporting/Resolution System (CIRS) item 1966. The SSA is an integral part of the systems engineering process, whereby safety is considered during planning, design, testing, and construction. A largely qualitative approach is used which incorporates operating experiences and recommendations from vendors, the constructor and the operating contractor. The risk assessment in this analysis characterizes the scenarios associated with fires in terms of relative risk and includes recommendations for mitigating all identified hazards. The priority for recommending and implementing mitigation control features is: (1) Incorporate

  18. In-Drift Precipitates/Salts Model

    Energy Technology Data Exchange (ETDEWEB)

    P. Mariner

    2004-11-09

    This report documents the development and validation of the in-drift precipitates/salts (IDPS) model. The IDPS model is a geochemical model designed to predict the postclosure effects of evaporation and deliquescence on the chemical composition of water within the Engineered Barrier System (EBS) in support of the Total System Performance Assessment for the License Application (TSPA-LA). Application of the model in support of TSPA-LA is documented in ''Engineered Barrier System: Physical and Chemical Environment Model'' (BSC 2004 [DIRS 169860]). Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration (BSC 2004 [DIRS 171156]) is the technical work plan (TWP) for this report. It called for a revision of the previous version of the report (BSC 2004 [DIRS 167734]) to achieve greater transparency, readability, data traceability, and report integration. The intended use of the IDPS model is to estimate and tabulate, within an appropriate level of confidence, the effects of evaporation, deliquescence, and potential environmental conditions on the pH, ionic strength, and chemical compositions of water and minerals on the drip shield or other location within the drift during the postclosure period. Specifically, the intended use is as follows: (1) To estimate, within an appropriate level of confidence, the effects of evaporation and deliquescence on the presence and composition of water occurring within the repository during the postclosure period (i.e., effects on pH, ionic strength, deliquescence relative humidity, total concentrations of dissolved components in the system Na-K-H-Mg-Ca-Al-Cl-F-NO{sub 3}-SO{sub 4}-Br-CO{sub 3}-SiO{sub 2}-CO{sub 2}-O{sub 2}-H{sub 2}O, and concentrations of the following aqueous species that potentially affect acid neutralizing capacity: HCO{sub 3}{sup -}, CO{sub 3}{sup 2-}, OH{sup -}, H{sup +}, HSO{sub 4}{sup -}, Ca{sup 2+}, Mg{sup 2+}, CaHCO{sub 3}{sup +}, MgHCO{sub 3

  19. Increased Arctic sea ice drift alters adult female polar bear movements and energetics.

    Science.gov (United States)

    Durner, George M; Douglas, David C; Albeke, Shannon E; Whiteman, John P; Amstrup, Steven C; Richardson, Evan; Wilson, Ryan R; Ben-David, Merav

    2017-09-01

    Recent reductions in thickness and extent have increased drift rates of Arctic sea ice. Increased ice drift could significantly affect the movements and the energy balance of polar bears (Ursus maritimus) which forage, nearly exclusively, on this substrate. We used radio-tracking and ice drift data to quantify the influence of increased drift on bear movements, and we modeled the consequences for energy demands of adult females in the Beaufort and Chukchi seas during two periods with different sea ice characteristics. Westward and northward drift of the sea ice used by polar bears in both regions increased between 1987-1998 and 1999-2013. To remain within their home ranges, polar bears responded to the higher westward ice drift with greater eastward movements, while their movements north in the spring and south in fall were frequently aided by ice motion. To compensate for more rapid westward ice drift in recent years, polar bears covered greater daily distances either by increasing their time spent active (7.6%-9.6%) or by increasing their travel speed (8.5%-8.9%). This increased their calculated annual energy expenditure by 1.8%-3.6% (depending on region and reproductive status), a cost that could be met by capturing an additional 1-3 seals/year. Polar bears selected similar habitats in both periods, indicating that faster drift did not alter habitat preferences. Compounding reduced foraging opportunities that result from habitat loss; changes in ice drift, and associated activity increases, likely exacerbate the physiological stress experienced by polar bears in a warming Arctic. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  20. Performance of drift chambers in a magnetic rigidity spectrometer for measuring the cosmic radiation

    International Nuclear Information System (INIS)

    Hof, M.; Bremerich, M.; Menn, W.; Pfeifer, C.; Reimer, O.; Simon, M.; Mitchell, J.W.; Barbier, L.M.; Christian, E.R.; Ormes, J.F.; Streitmatter, R.E.; Golden, R.L.; Stochaj, S.J.

    1994-01-01

    A drift chamber tracking system was developed and flown as part of the IMAX balloon-borne magnetic spectrometer. The drift chamber uses a hexagonal drift-cell structure and is filled with pure CO 2 gas. It operated with high efficiency in the strong and inhomogenous field of a superconducting magnet, demonstrating a spatial resolution of better than 100 μm over most of the drift path for singly charged particles, as well as for helium and lithium nuclei. The drift chamber portion of the spectrometer achieved a maximum detectable rigidity of 175 and 250 GV/c for protons and helium respectively. ((orig.))

  1. Scalloped Implant-Abutment Connection Compared to Conventional Flat Implant-Abutment Connection

    DEFF Research Database (Denmark)

    Starch-Jensen, Thomas; Christensen, Ann-Eva; Lorenzen, Henning

    2017-01-01

    OBJECTIVES: The objective was to test the hypothesis of no difference in implant treatment outcome after installation of implants with a scalloped implant-abutment connection compared to a flat implant-abutment connection. MATERIAL AND METHODS: A MEDLINE (PubMed), Embase and Cochrane library search...... of suprastructures has never been compared within the same study. High implant survival rate was reported in all the included studies. Significantly more peri-implant marginal bone loss, higher probing depth score, bleeding score and gingival score was observed around implants with a scalloped implant-abutment...... loss around implants with a scalloped implant-abutment connection. CONCLUSIONS: A scalloped implant-abutment connection seems to be associated with higher peri-implant marginal bone loss compared to a flat implant-abutment connection. Therefore, the hypothesis of the present systematic review must...

  2. Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Lukco, Dorothy; Nguyen, Vu; Savrun, Ender

    2012-01-01

    We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 C. The previously observed maximum drift of +/- 10 mV of the reference offset voltage at 600 C was reduced to within +/- 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 C.

  3. Precise muon drift tube detectors for high background rate conditions

    Energy Technology Data Exchange (ETDEWEB)

    Engl, Albert

    2011-08-04

    The muon spectrometer of the ATLAS-experiment at the Large Hadron Collider consists of drift tube chambers, which provide the precise measurement of trajectories of traversing muons. In order to determine the momentum of the muons with high precision, the measurement of the position of the muon in a single tube has to be more accurate than {sigma}{<=}100 {mu}m. The large cross section of proton-proton-collisions and the high luminosity of the accelerator cause relevant background of neutrons and {gamma}s in the muon spectrometer. During the next decade a luminosity upgrade to 5.10{sup 34} cm{sup -2}s{sup -1} is planned, which will increase the background counting rates considerably. In this context this work deals with the further development of the existing drift chamber technology to provide the required accuracy of the position measurement under high background conditions. Two approaches of improving the drift tube chambers are described: - In regions of moderate background rates a faster and more linear drift gas can provide precise position measurement without changing the existing hardware. - At very high background rates drift tube chambers consisting of tubes with a diameter of 15 mm are a valuable candidate to substitute the CSC muon chambers. The single tube resolution of the gas mixture Ar:CO{sub 2}:N{sub 2} in the ratio of 96:3:1 Vol %, which is more linear and faster as the currently used drift gas Ar:CO{sub 2} in the ratio of 97:3 Vol %, was determined at the Cosmic Ray Measurement Facility at Garching and at high {gamma}-background counting rates at the Gamma Irradiation Facility at CERN. The alternative gas mixture shows similar resolution without background. At high background counting rates it shows better resolution as the standard gas. To analyse the data the various parts of the setup have to be aligned precisely to each other. The change to an alternative gas mixture allows the use of the existing hardware. The second approach are drift tubes

  4. Transient chaotic transport in dissipative drift motion

    Energy Technology Data Exchange (ETDEWEB)

    Oyarzabal, R.S. [Pós-Graduação em Ciências/Física, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Szezech, J.D. [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Batista, A.M., E-mail: antoniomarcosbatista@gmail.com [Departamento de Matemática e Estatística, Universidade Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR (Brazil); Souza, S.L.T. de [Departamento de Física e Matemática, Universidade Federal de São João del Rei, 36420-000, Ouro Branco, MG (Brazil); Caldas, I.L. [Instituto de Física, Universidade de São Paulo, 05315-970, São Paulo, SP (Brazil); Viana, R.L. [Departamento de Física, Universidade Federal do Paraná, 81531-990, Curitiba, PR (Brazil); Sanjuán, M.A.F. [Departamento de Física, Universidad Rey Juan Carlos, Tulipán s/n, 28933 Móstoles, Madrid (Spain)

    2016-04-22

    Highlights: • We consider a situation for which a chaotic transient is present in the dynamics of the two-wave model with damping. • The damping in plasma models can be a way for study a realistic behavior of confinement due the collisional effect. • The escape time as a function of the damping obey a power-law scaling. • We have made a qualitative transport analysis with a simple model that can be useful for more complete models. • We have shown that the pattern of the basin of attraction depends on the damping parameter. - Abstract: We investigate chaotic particle transport in magnetised plasmas with two electrostatic drift waves. Considering dissipation in the drift motion, we verify that the removed KAM surfaces originate periodic attractors with their corresponding basins of attraction. We show that the properties of the basins depend on the dissipation and the space-averaged escape time decays exponentially when the dissipation increases. We find positive finite time Lyapunov exponents in dissipative drift motion, consequently the trajectories exhibit transient chaotic transport. These features indicate how the transient plasma transport depends on the dissipation.

  5. Drift-free equilibrium reconstruction using magnetic probes

    International Nuclear Information System (INIS)

    Lister, J.B.; Saint-Laurent, F.; Moreau, Ph.; Lukash, V.E.

    2004-01-01

    Tore Supra has recently demonstrated the existence of a new effect, causing magnetic diagnostic drift and not previously taken into consideration, which is slight rotation of the magnetic probes by thermo-mechanical distortion during 300 second pulses absorbing more than 1 GJ into the plasma, resulting in time-dependent pick-up of the toroidal magnetic field. The Tore Supra control system tracks these offsets and displaces the last closed flux surface from its reference location. This new effect of long high-power pulses has the properties of a drift, generating a slowly evolving unmeasured offset to the integrated magnetic signals. For this reason, we have decided to take another look at methods of reconstructing an offset-free equilibrium from magnetic diagnostics, whereas most proposed approaches to drift compensation rely on non-magnetic, non-integrated measurements of plasma emission or reflectometry. We note that a similar approach was tested on HT-7 using the induction in the poloidal field coils as the sole measurement of the radial position, modulating in a similar way. Although this present work uses magnetic diagnostics, we are extending this idea to include the vertical position and the deformation of highly shaped plasmas

  6. SU-F-T-279: Impact of Beam Energy Drifts On IMRT Delivery Accuracy

    International Nuclear Information System (INIS)

    Goddu, S; Kamal, G; Herman, A; Edwards, S; Cai, B; Yaddanapudi, S; Oddiraju, S; Rangaraj, D; Mutic, S

    2016-01-01

    Purpose: According to TG-40 percent-depth-dose (PDD) tolerance is ±2% but TG-142 is ±1%. Now the question is, which one is relevant in IMRT era? The primary objective of this study is to evaluate dosimetric impact of beam-energy-drifts on IMRT-delivery. Methods: Beam-energy drifts were simulated by adjusting Linac’s bending-magnet-current (BMC) followed by tuning the pulse-forming network and adjusting gun-current. PDD change of −0.6% and +1.2% were tested. Planar-dosimetry measurements were performed using an ionization-chamber-array in solid-water phantoms. Study includes 10-head-and-neck and 3-breast cancer patients. en-face beam-deliveries were also tested at 1.3cm and 5.3cm depths. Composite and single-field dose-distributions were compared against the plans to determine %Gamma pass-rates (%GPRs). For plan dose comparisons, changes in %Gamma pass-rates (cPGPRs) were computed/reported to exclude the differences between dose-computation and delivery. Dose distributions of the drifted-energies were compared against their baseline measurements to determine the% GPRs. A Gamma criteria of 3%/3mm was considered for plan-dose comparisons while 3%/1mm used for measured dose intercomparisons. Results: For composite-dose delivery, average cPGPRs were 0.41%±2.48% and −2.54%±3.65% for low-energy (LE) and high-energy (HE) drifts, respectively. For measured dose inter-comparisons, the average%GPRs were 98.4%±2.2% (LE-drift) and 95.8%±4.0 (HE-drift). The average %GPR of 92.6%±4.3% was noted for the worst-case scenario comparing LE-drift to HE-drift. All en-face beams at 5.3 cm depth have cPGPRs within ±4% of the baseline-energy measurements. However, greater variations were noted for 1.3cm depth. Average %GPRs for drifted energies were >99% at 5.3cm and >97% at 1.3cm depths. However, for the worst-case scenario (LE-drift to HE-drift) these numbers dropped to 95.2% at 5.3cm and 93.1% at 1.3cm depths. Conclusion: The dosimetric impact of beam-energy drifts was

  7. Low Power Measurements on a Finger Drift Tube Linac

    CERN Document Server

    Schempp, A

    2004-01-01

    The efficiency of RFQs decreases at higher particle energies. The DTL structures used in this energy regions have a defocusing influence on the beam. To achieve a focusing effect, fingers with quadrupole symmetry were added to the drift tubes. Driven by the same power supply as the drift tubes, the fingers do not need an additional power source or feedthrough. Beam dynamics have been studied with PARMTEQ . Detailed analysis of the field distribution was done and the geometry of the finger array has been optimized with respect to beam dynamics. A spiral loaded cavity with finger drift tubes was built up and low power measurements were done. In this contribution, the results of the rf simulating with Microwave Studio are shown in comparison with bead pertubation measurement on a prototype cavity.

  8. Noncontact measurement of electrostatic fields: Verification of modeled potentials within ion mobility spectrometer drift tube designs

    International Nuclear Information System (INIS)

    Scott, Jill R.; Tremblay, Paul L.

    2007-01-01

    The heart of an ion mobility spectrometer is the drift region where ion separation occurs. While the electrostatic potentials within a drift tube design can be modeled, no method for independently validating the electrostatic field has previously been reported. Two basic drift tube designs were modeled using SIMION 7.0 to reveal the expected electrostatic fields: (1) A traditional alternating set of electrodes and insulators and (2) a truly linear drift tube. One version of the alternating electrode/insulator drift tube and two versions of linear drift tubes were then fabricated. The stacked alternating electrodes/insulators were connected through a resistor network to generate the electrostatic gradient in the drift tube. The two linear drift tube designs consisted of two types of resistive drift tubes with one tube consisting of a resistive coating within an insulating tube and the other tube composed of resistive ferrites. The electrostatic fields within each type of drift tube were then evaluated by a noncontact method using a Kelvin-Zisman type electrostatic voltmeter and probe (results for alternative measurement methods provided in supplementary material). The experimental results were then compared with the electrostatic fields predicted by SIMION. Both the modeling and experimental measurements reveal that the electrostatic fields within a stacked ion mobility spectrometer drift tube are only pseudo-linear, while the electrostatic fields within a resistive drift tube approach perfect linearity

  9. Job satisfaction and preference drift.

    NARCIS (Netherlands)

    Maassen van den Brink, H.; Groot, W.J.N.

    1999-01-01

    Most empirical studies do not find that higher wages lead to more job satisfaction. In this paper we argue that the insignificant effect of wages on job satisfaction is due to preference drift. We adapt the standard ordered response model to allow for preference shifts. The empirical results support

  10. Effects of magnetic drift tangential to magnetic surfaces on neoclassical transport in non-axisymmetric plasmas

    International Nuclear Information System (INIS)

    Matsuoka, Seikichi; Satake, Shinsuke; Kanno, Ryutaro; Sugama, Hideo

    2015-01-01

    In evaluating neoclassical transport by radially local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic drift on the local neoclassical transport is investigated. To retain the effect of the tangential magnetic drift in the local treatment of neoclassical transport, a new local formulation for the drift kinetic simulation is developed. The compressibility of the phase-space volume caused by the tangential magnetic drift is regarded as a source term for the drift kinetic equation, which is solved by using a two-weight δf Monte Carlo method for non-Hamiltonian system [G. Hu and J. A. Krommes, Phys. Plasmas 1, 863 (1994)]. It is demonstrated that the effect of the drift is negligible for the neoclassical transport in tokamaks. In non-axisymmetric systems, however, the tangential magnetic drift substantially changes the dependence of the neoclassical transport on the radial electric field E r . The peaked behavior of the neoclassical radial fluxes around E r  =   0 observed in conventional local neoclassical transport simulations is removed by taking the tangential magnetic drift into account

  11. Effects of magnetic drift tangential to magnetic surfaces on neoclassical transport in non-axisymmetric plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Seikichi, E-mail: matsuoka@rist.or.jp [Research Organization for Information Science and Technology, 6F Kimec-Center Build., 1-5-2 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047 (Japan); Satake, Shinsuke; Kanno, Ryutaro [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Department of Fusion Science, SOKENDAI (The Graduate University for Advanced Studies), 322-6 Oroshi-cho, Toki 509-5292 (Japan); Sugama, Hideo [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2015-07-15

    In evaluating neoclassical transport by radially local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic drift on the local neoclassical transport is investigated. To retain the effect of the tangential magnetic drift in the local treatment of neoclassical transport, a new local formulation for the drift kinetic simulation is developed. The compressibility of the phase-space volume caused by the tangential magnetic drift is regarded as a source term for the drift kinetic equation, which is solved by using a two-weight δf Monte Carlo method for non-Hamiltonian system [G. Hu and J. A. Krommes, Phys. Plasmas 1, 863 (1994)]. It is demonstrated that the effect of the drift is negligible for the neoclassical transport in tokamaks. In non-axisymmetric systems, however, the tangential magnetic drift substantially changes the dependence of the neoclassical transport on the radial electric field E{sub r}. The peaked behavior of the neoclassical radial fluxes around E{sub r }={sub  }0 observed in conventional local neoclassical transport simulations is removed by taking the tangential magnetic drift into account.

  12. Electron drift velocity in argon-methane mixture

    International Nuclear Information System (INIS)

    Hakeem, N.El; Mathieson, E.

    1978-01-01

    Described are the results of a series of measurements of electron drift velocity taken with samples of chemically pure grade gas mixture of Ar-10% CH 4 (N 2 2 2 2 O<2 ppm). The measured drift velocity is plotted as a function of the ratio of electric field to pressure in the range from 0.05 to 0.8 V/cmxtorr. The measurements are reproducible only to within 4%. The results of numerical calculations employing the well-established argon elastic and methane elastic and inelastic cross sections are also included. The disagreement from the present experimental results, and from those obtained elsewhere, is rather puzzling

  13. Accurate computer simulation of a drift chamber

    CERN Document Server

    Killian, T J

    1980-01-01

    The author describes a general purpose program for drift chamber studies. First the capacitance matrix is calculated using a Green's function technique. The matrix is used in a linear-least-squares fit to choose optimal operating voltages. Next the electric field is computed, and given knowledge of gas parameters and magnetic field environment, a family of electron trajectories is determined. These are finally used to make drift distance vs time curves which may be used directly by a track reconstruction program. The results are compared with data obtained from the cylindrical chamber in the Axial Field Magnet experiment at the CERN ISR. (1 refs).

  14. Lagrangians for plasmas in drift-fluid approximation

    International Nuclear Information System (INIS)

    Pfirsch, D.; Correa-Restrepo, D.

    1996-10-01

    For drift waves and related instabilities conservation laws can play a crucial role. In an ideal theory these conservation laws are guaranteed when a Lagrangian can be found from which the equations for the various quantities result by Hamilton's principle. Such a Lagrangian for plasmas in drift-fluid approximation was obtained by a heuristic method in a recent paper by Pfirsch and Correa-Restrepo. In the present paper the same Lagrangian is derived from the exact multi-fluid Lagrangian via an iterative approximation procedure which resembles the standard method usually applied to the equations of motion. That method, however, does not guarantee all the conservation laws to hold. (orig.)

  15. Organic Scintillator Detector Response Simulations with DRiFT

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Madison Theresa [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bates, Cameron Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mckigney, Edward Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pinilla, Maria Isabel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solomon, Jr., Clell Jeffrey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sood, Avneet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-19

    Accurate detector modeling is a requirement to design systems in many non-proliferation scenarios; by determining a Detector’s Response Function (DRF) to incident radiation, it is possible characterize measurements of unknown sources. DRiFT is intended to post-process MCNP® output and create realistic detector spectra. Capabilities currently under development include the simulation of semiconductor, gas, and (as is discussed in this work) scintillator detector physics. Energy spectra and pulse shape discrimination (PSD) trends for incident photon and neutron radiation have been reproduced by DRiFT.

  16. Phenomena accompanying gradient-B drift injection of energetic ions into Tokamak plasmas

    International Nuclear Information System (INIS)

    Goldston, R.J.; Jassby, D.L.

    1976-01-01

    The application of vertically asymmetric toroidal-field ripple, in order to permit the gradient B-drift injection and subsequent capture of energetic ions, results in a new radial diffusion of banana orbits. The nearly mono-kinetic velocity distribution of gradient B-drifting ions in the outer plasma region represents a large source of free energy; and the nonambipolar inward drift of these ions modifies the radial electric field

  17. Quantification of Stokes Drift as a Mechanism for Surface Oil Advection in the DWH Oil Spill

    Science.gov (United States)

    Clark, M.

    2013-12-01

    Stokes drift has previously been qualitatively shown to be a factor in ocean surface particle transport, but has never been comprehensively quantified. In addition, most operational ocean particle advection models used during the Deepwater Horizon oil spill do not explicitly account for Stokes drift, instead using a simple parameterization based on wind drift (or ignoring it completely). This research works to quantify Stokes drift via direct calculation, with a focus on shallow water, where Stokes drift is more likely to have a relatively large impact compared to other transport processes such as ocean currents. For this study, WaveWatch III modeled waves in the Gulf of Mexico are used, from which Stokes drift is calculated using the peak wave period and significant wave height outputs. Trajectories are also calculated to examine the role Stokes drift plays in bringing surface particles (and specifically surface oil slicks) onshore. The impact of Stokes drift is compared to transport by currents and traditional estimates of wind drift.

  18. Analysis of zonal flow bifurcations in 3D drift wave turbulence simulations

    International Nuclear Information System (INIS)

    Kammel, Andreas

    2012-01-01

    The main issue of experimental magnetic fusion devices lies with their inherently high turbulent transport, preventing long-term plasma confinement. A deeper understanding of the underlying transport processes is therefore desirable, especially in the high-gradient tokamak edge which marks the location of the drift wave regime as well as the outer boundary of the still badly understood high confinement mode. One of the most promising plasma features possibly connected to a complete bifurcation theory for the transition to this H-mode is found in large-scale phenomena capable of regulating radial transport through vortex shearing - i.e. zonal flows, linearly stable large-scale poloidal vector E x vector B-modes based on radial flux surface averages of the potential gradient generated through turbulent self-organization. Despite their relevance, few detailed turbulence studies of drift wave-based zonal flows have been undertaken, and none of them have explicitly targeted bifurcations - or, within a resistive sheared-slab environment, observed zonal flows at all. In this work, both analytical means and the two-fluid code NLET are used to analyze a reduced set of Hasegawa-Wakatani equations, describing a sheared collisional drift wave system without curvature. The characteristics of the drift waves themselves, as well as those of the drift wave-based zonal flows and their retroaction on the drift wave turbulence are examined. The single dimensionless parameter ρ s proposed in previous analytical models is examined numerically and shown to divide the drift wave scale into two transport regimes, the behavioral characteristics of which agree perfectly with theoretical expectations. This transport transition correlates with a transition from pure drift wave turbulence at low ρ s into the high-ρ s zonal flow regime. The associated threshold has been more clearly identified by tracing it back to a tipping of the ratio between a newly proposed frequency gradient length at

  19. Nonparametric estimates of drift and diffusion profiles via Fokker-Planck algebra.

    Science.gov (United States)

    Lund, Steven P; Hubbard, Joseph B; Halter, Michael

    2014-11-06

    Diffusion processes superimposed upon deterministic motion play a key role in understanding and controlling the transport of matter, energy, momentum, and even information in physics, chemistry, material science, biology, and communications technology. Given functions defining these random and deterministic components, the Fokker-Planck (FP) equation is often used to model these diffusive systems. Many methods exist for estimating the drift and diffusion profiles from one or more identifiable diffusive trajectories; however, when many identical entities diffuse simultaneously, it may not be possible to identify individual trajectories. Here we present a method capable of simultaneously providing nonparametric estimates for both drift and diffusion profiles from evolving density profiles, requiring only the validity of Langevin/FP dynamics. This algebraic FP manipulation provides a flexible and robust framework for estimating stationary drift and diffusion coefficient profiles, is not based on fluctuation theory or solved diffusion equations, and may facilitate predictions for many experimental systems. We illustrate this approach on experimental data obtained from a model lipid bilayer system exhibiting free diffusion and electric field induced drift. The wide range over which this approach provides accurate estimates for drift and diffusion profiles is demonstrated through simulation.

  20. System of cylindrical drift chambers in a superconducting solenoid

    International Nuclear Information System (INIS)

    Camilleri, L.; Blumenfeld, B.J.; Dimcovski, Z.

    1978-01-01

    A superconducting solenoid at the CERN ISR was equipped with a system of high accuracy cylindrical drift chambers. This detector consists of eight layers of field shaped drift cells with a delay line opposite each sense wire to provide coupled two dimensional readout. The design, construction, and operation of this system are discussed. The resolution and performance of the delay lines and sense wires under ISR running conditions are shown