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Sample records for pulse pressure analysis

  1. Single pulse analysis of intracranial pressure for a hydrocephalus implant.

    Science.gov (United States)

    Elixmann, I M; Hansinger, J; Goffin, C; Antes, S; Radermacher, K; Leonhardt, S

    2012-01-01

    The intracranial pressure (ICP) waveform contains important diagnostic information. Changes in ICP are associated with changes of the pulse waveform. This change has explicitly been observed in 13 infusion tests by analyzing 100 Hz ICP data. An algorithm is proposed which automatically extracts the pulse waves and categorizes them into predefined patterns. A developed algorithm determined 88 %±8 % (mean ±SD) of all classified pulse waves correctly on predefined patterns. This algorithm has low computational cost and is independent of a pressure drift in the sensor by using only the relationship between special waveform characteristics. Hence, it could be implemented on a microcontroller of a future electromechanic hydrocephalus shunt system to control the drainage of cerebrospinal fluid (CSF).

  2. Central venous pulse pressure analysis using an R-synchronized pressure measurement system.

    Science.gov (United States)

    Fujita, Yoshihisa; Hayashi, Daisuke; Wada, Shinya; Yoshioka, Naoki; Yasukawa, Takeshi; Pestel, Gunther

    2006-12-01

    The information derived from central venous catheters is underused. We developed an EKG-R synchronization and averaging system to obtained distinct CVP waveforms and analyzed components of these. Twenty-five paralyzed surgical patients undergoing CVP monitoring under mechanical ventilation were studied. CVP and EKG signals were analyzed employing our system, the mean CVP and CVP at end-diastole during expiration were compared, and CVP waveform components were measured using this system. CVP waveforms were clearly visualized in all patients. They showed the a peak to be 1.8+/- 0.7 mmHg, which was the highest of three peaks, and the x trough to be lower than the y trough (-1.6+/- 0.7 mmHg and -0.9+/- 0.5 mmHg, respectively), with a mean pulse pressure of 3.4 mmHg. The difference between the mean CVP and CVP at end-diastole during expiration was 0.58+/- 0.81 mmHg. The mean CVP can be used as an index of right ventricular preload in patients under mechanical ventilation with regular sinus rhythm. Our newly developed system is useful for clinical monitoring and for education in circulatory physiology.

  3. Hydraulic pressure pulses with elastic and plastic structural flexibility: test and analysis (LWBR Development Program)

    International Nuclear Information System (INIS)

    Schwirian, R.E.

    1978-03-01

    Pressure pulse tests were conducted with a flexible test section in a test vessel filled with room temperature water. The pressure pulses were generated with a drop hammer and piston pulse generator and were of a sufficient magnitude to cause plastic deformation of the test section. Because of the strong pressure relief effect of the deforming test section, pressure pulse magnitudes were below 265 psig in magnitude and had durations of 50 to 55 msecs. Calculations performed with the FLASH-35 bi-linear hysteresis model of structural deformation show good agreement with experiment. In particular, FLASH 35 adequately predicts the decrease in peak pressure and the increase in pulse duration due to elastic and plastic deformation of the test section. Predictions of flexible member motion are good, but are less satisfactory than the pressure pulse results due to uncertainties in the values of yield point and beyond yield stiffness used to model the various flexible members. Coupled with this is a strong sensitivity of the FLASH 35 predictions to the values of yield point and beyond yield stiffness chosen for the various flexible members. The test data versus calculation comparisons presented here provide preliminary qualification for FLASH 35 calculations of transient hydraulic pressures and pressure differentials in the presence of flexible structural members which deform both elastically and plastically

  4. Computer code for the analysis of destructive pressure generation process during a fuel failure accident, PULSE-2

    International Nuclear Information System (INIS)

    Fujishiro, Toshio

    1978-03-01

    The computer code PULSE-2 has been developed for the analysis of pressure pulse generation process when hot fuel particles come into contact with the coolant in a fuel rod failure accident. In the program, it is assumed that hot fuel fragments mix with the coolant instantly and homogeneously in the failure region. Then, the rapid vaporization of the coolant and transient pressure rise in failure region, and the movement of ejected coolant slugs are calculated. The effect of a fuel-particle size distribution is taken into consideration. Heat conduction in the fuel particles and heat transfer at fuel-coolant interface are calculated. Temperature, pressure and void fraction in the mixed region are calculated from the average enthalpy. With physical property subroutines for liquid sodium and water, the model is usable for both LMFBR and LWR conditions. (auth.)

  5. Morning pulse pressure is associated more strongly with elevated albuminuria than systolic blood pressure in patients with type 2 diabetes mellitus: post hoc analysis of a cross-sectional multicenter study.

    Science.gov (United States)

    Ushigome, Emi; Fukui, Michiaki; Hamaguchi, Masahide; Matsumoto, Shinobu; Mineoka, Yusuke; Nakanishi, Naoko; Senmaru, Takafumi; Yamazaki, Masahiro; Hasegawa, Goji; Nakamura, Naoto

    2013-09-01

    Recently, focus has been directed toward pulse pressure as a potentially independent risk factor for micro- and macrovascular disease. This study was designed to examine the relationship between pulse pressure taken at home and elevated albuminuria in patients with type 2 diabetes. This study is a post hoc analysis of a cross-sectional multicenter study. Home blood pressure measurements were performed for 14 consecutive days in 858 patients with type 2 diabetes. We investigated the relationship between systolic blood pressure or pulse pressure in the morning or in the evening and urinary albumin excretion using univariate and multivariate analyses. Furthermore, we measured area under the receiver-operating characteristic curve (AUC) to compare the ability to identify elevated albuminuria, defined as urinary albumin excretion equal to or more than 30 mg/g creatinine, of systolic blood pressure or pulse pressure. Morning systolic blood pressure (β=0.339, Ppressure (β=0.378, PAUC for elevated albuminuria in morning systolic blood pressure and morning pulse pressure were 0.668 (0.632-0.705; PAUC of morning pulse pressure was significantly greater than that of morning systolic blood pressure (P=0.040). Our findings implicate that morning pulse pressure is associated with elevated albuminuria in patients with type 2 diabetes, which suggests that lowering morning pulse pressure could prevent the development and progression of diabetic nephropathy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Pulse pressure and diurnal blood pressure variation

    DEFF Research Database (Denmark)

    Knudsen, Søren Tang; Poulsen, Per Løgstrup; Hansen, Klavs Würgler

    2002-01-01

    retinopathy, nephropathy, macrovascular disease, PP, and diurnal BP variation in a group of type 2 diabetic patients. METHODS: In 80 type 2 diabetic patients we performed 24-h ambulatory BP (AMBP) and fundus photographs. Urinary albumin excretion was evaluated by urinary albumin/creatinine ratio. Presence...... or absence of macrovascular disease was assessed by an independent physician. RESULTS: Forty-nine patients had no detectable retinal changes (grade 1), 13 had grade 2 retinopathy, and 18 had more advanced retinopathy (grades 3-6). Compared to patients without retinopathy (grade 1), patients with grades 2......BACKGROUND: In nondiabetic subjects pulse pressure (PP) is an independent predictor of cardiovascular disease and microalbuminuria. Reduced circadian blood pressure (BP) variation is a potential risk factor for the development of diabetic complications. We investigated the association between...

  7. Analysis of the scintillation mechanism in a pressurized 4He fast neutron detector using pulse shape fitting

    Directory of Open Access Journals (Sweden)

    R.P. Kelley

    2015-03-01

    Full Text Available An empirical investigation of the scintillation mechanism in a pressurized 4He gas fast neutron detector was conducted using pulse shape fitting. Scintillation signals from neutron interactions were measured and averaged to produce a single generic neutron pulse shape from both a 252Cf spontaneous fission source and a (d,d neutron generator. An expression for light output over time was then developed by treating the decay of helium excited states in the same manner as the decay of radioactive isotopes. This pulse shape expression was fitted to the measured neutron pulse shape using a least-squares optimization algorithm, allowing an empirical analysis of the mechanism of scintillation inside the 4He detector. A further understanding of this mechanism in the 4He detector will advance the use of this system as a neutron spectrometer. For 252Cf neutrons, the triplet and singlet time constants were found to be 970 ns and 686 ns, respectively. For neutrons from the (d,d generator, the time constants were found to be 884 ns and 636 ns. Differences were noted in the magnitude of these parameters compared to previously published data, however the general relationships were noted to be the same and checked with expected trends from theory. Of the excited helium states produced from a 252Cf neutron interaction, 76% were found to be born as triplet states, similar to the result from the neutron generator of 71%. The two sources yielded similar pulse shapes despite having very different neutron energy spectra, validating the robustness of the fits across various neutron energies.

  8. Pulse Pressure: An Indicator of Heart Health?

    Science.gov (United States)

    ... pressure should also be considered alongside pulse pressure values. Higher systolic and diastolic pairs imply higher risk than ... endorse any of the third party products and services advertised. Advertising ... Education and Research. © 1998-2018 Mayo Foundation for Medical ...

  9. Electrical and spectroscopic analysis of mono- and multi-tip pulsed corona discharges in air at atmospheric pressure

    Science.gov (United States)

    Mraihi, A.; Merbahi, N.; Yousfi, M.; Abahazem, A.; Eichwald, O.

    2011-12-01

    This work is devoted to the analysis of experimental results obtained in dry air at atmospheric pressure in a positive point-to-plane corona discharge under a pulsed applied voltage in the cases of anodic mono- and multi-tips. In the mono-tip case, the peak corona current is analysed as a function of several experimental parameters such as magnitude, frequency and duration of pulsed voltage and gap distance. The variation of the corona discharge current is correlated with the ozone production. Then in the multi-tip case, the electrical behaviour is analysed as a function of the distance between two contiguous tips and the tip number in order to highlight the region of creation active species for the lowest dissipated power. Intensified charge-coupled device pictures and electric field calculations as a function of inter-tip distance are performed to analyse the mutual effect between two contiguous tips. The optical emission spectra are measured in the UV-visible-NIR wavelength range between 200 nm and 800 nm, in order to identify the main excited species formed in an air corona discharge such as the usual first and second positive systems with first negative systems of molecular nitrogen. The identification of atomic species (O triplet and N) and the quenching of NOγ emission bands are also emphasized.

  10. Electrical and spectroscopic analysis of mono- and multi-tip pulsed corona discharges in air at atmospheric pressure

    International Nuclear Information System (INIS)

    Mraihi, A; Merbahi, N; Yousfi, M; Abahazem, A; Eichwald, O

    2011-01-01

    This work is devoted to the analysis of experimental results obtained in dry air at atmospheric pressure in a positive point-to-plane corona discharge under a pulsed applied voltage in the cases of anodic mono- and multi-tips. In the mono-tip case, the peak corona current is analysed as a function of several experimental parameters such as magnitude, frequency and duration of pulsed voltage and gap distance. The variation of the corona discharge current is correlated with the ozone production. Then in the multi-tip case, the electrical behaviour is analysed as a function of the distance between two contiguous tips and the tip number in order to highlight the region of creation active species for the lowest dissipated power. Intensified charge-coupled device pictures and electric field calculations as a function of inter-tip distance are performed to analyse the mutual effect between two contiguous tips. The optical emission spectra are measured in the UV–visible–NIR wavelength range between 200 nm and 800 nm, in order to identify the main excited species formed in an air corona discharge such as the usual first and second positive systems with first negative systems of molecular nitrogen. The identification of atomic species (O triplet and N) and the quenching of NOγ emission bands are also emphasized.

  11. Considerations for SphygmoCor radial artery pulse wave analysis: side selection and peripheral arterial blood pressure calibration.

    Science.gov (United States)

    Martin, Jeffrey S; Borges, Alexandra R; Christy, John B; Beck, Darren T

    2015-10-01

    Methods employed for pulse wave analysis (PWA) and peripheral blood pressure (PBP) calibration vary. The purpose of this study was to evaluate the agreement of SphygmoCor PWA parameters derived from radial artery tonometry when considering (1) timing (before vs. after tonometry) and side selection (ipsilateral vs. contralateral limb) for PBP calibration and (2) side selection for tonometry (left vs. right arm). In 34 subjects (aged 21.9 ± 2.3 years), bilateral radial artery tonometry was performed simultaneously on three instances. PBP assessment via oscillometric sphygmomanometry in the left arm only and both arms simultaneously occurred following the first and second instances of tonometry, respectively. Significant within arm differences in PWA parameters derived before and after PBP measurement were observed in the right arm only (for example, aortic systolic blood pressure, Δ=0.38 ± 0.64 mm Hg). Simultaneously captured bilateral PWA variables demonstrated significant between arm differences in 88% (14/16) and 56% (9/16) of outcome variables when calibrated to within arm and equivalent PBP, respectively. Moreover, the right arm consistently demonstrated lower values for clinical PWA variables (for example, augmentation index, bias=-2.79%). However, 26% (n=9) of participants presented with clinically significant differences (>10 mm Hg) in bilateral PBP and their exclusion from analysis abolished most between arm differences observed. SphygmoCor PWA in the right radial artery results in greater variability independent of the timing of PBP measurement and magnitude of calibration pressures in young subjects. Moreover, bilateral PBP measurement is imperative to identify subjects in whom a significant difference in bilateral PWA outcomes may exist.

  12. Pulse Waveform and Transcranial Doppler Analysis during Lower Body Negative Pressure

    Science.gov (United States)

    1993-04-01

    26, 23]. The application of negative pressure to the body for scientific or medical purposes was first used in 1841 by Junod , who used it to create a...localized hyperemia [26]. Junod also suggested that it could be used prior to invasive surgical procedures, since the syncope it was able to produce

  13. Analysis of physiological (pao/sub 2/, pulse and blood pressure) changes during modified ect under general anaesthesia

    International Nuclear Information System (INIS)

    Shah, M.; Shah, H.A.; Shah, F.S.

    2015-01-01

    To study the changes in physiological parameters i e PAO2, pulse and blood pressure changes during ECT under GA. Study Design: Quasi-experimental study. Place and Duration of Study: Department of Psychiatry and Department of Anaesthesiology, Combined Military Hospital Abbottabad from Sep 2009 to Feb 2010. Patients and Methods: A total of 50 patients with depression were given four separate ECT sessions each. All patients were anaesthetized using propofol 180-200 mg I/V and suxamethonium 50 mg i e 0.75-1 mg per kg I/V without atropine. They were stratified according to physiological changes including PAO2, pulse and blood pressure at 1, 2 and 5 min after ECT. Oxygen saturation was measured using a pulse oximeter, which measures saturations in the range of 65-100%. Results: Age range was 19-65 years; mean 46 years (SD+-13). Mean diastolic BP before ECT was 84.72 that decreased post ECT ie 78.02 and 77.46 and 74.44 at interval of 1, 2 and 5 minute respectively. Post-ECT pulse and PAO2 behaved similarly. Post ECT systolic BP decreased at 1 and 5 minutes. Pulse rate decreased after ECT. Conclusion: ECT under propofol is one of the most effective and safe modality of treatment for psychiatric patients under the supervision of qualified psychiatrists and anaesthesiologists and it gives more stable hemodynamic changes. (author)

  14. Analysis of the dynamic response of a double rupture disc assembly to simulated sodium-water reaction pressure pulses

    International Nuclear Information System (INIS)

    Leonard, J.R.

    1980-03-01

    A series of double rupture disc experiments were conducted in 1979 to evaluate the dynamic response characteristics of this pressure relief apparatus. The tests were performed in a facility with water simulating sodium and rising pressure pulses representative of the pressure increase resulting from a water/steam leak from a steam generator into sodium in the intermediate heat transport system of a breeder reactor power plant. Maximum source pressures ranged in magnitude from 50 psi to 800 psi. Dynamic response characteristics of each of the two rupture discs were similar to those observed in larger scale sodium-water experiments conducted in the Series I and Series II Large Leak Test Program at the Energy Technology Engineering Center. The SRI double rupture disc dynamic behavior was found to be consistent and amendable to modelling in the TRANSWRAP II computer code. A series of correlations which represent rupture disc buckling parameters were developed for use in the TRANSWRAP II code. The semi-empirical modeling of the rupture discs in the TRANSWRAP II code showed very good agreement with the experimental results

  15. Monitoring of deposits in pipelines using pressure pulse technology

    Energy Technology Data Exchange (ETDEWEB)

    Gudmundsson, Jon S.; Celius, Harald K.

    2005-07-01

    The basis of pressure pulse technology is presented in terms of the water hammer equation, the pipeline pressure drop equation and the equation for speed of sound in multiphase mixtures. The technology can be used for a range of applications, from on-line monitoring of flowing conditions to on-demand measurements and analysis to locate and quantify deposits in wells and pipelines. While pressure pulse measurements are low-cost and easy to implement, the commercial use of pressure pulse technology has resulted from extensive field experience and substantial in-house software development. Simulation tools were used to illustrate the effect of a 2 mm thick deposit, 500 m long and located 375 m from a quick-acting valve. The simulation conditions used are typical for multiphase gas-oil flow along a horizontal 2 km long pipeline from wellhead to manifold. (Author)

  16. Pulsed rf operation analysis

    International Nuclear Information System (INIS)

    Puglisi, M.; Cornacchia, M.

    1981-01-01

    The need for a very low final amplifier output impedance, always associated with class A operation, requires a very large power waste in the final tube. The recently suggested pulsed rf operation, while saving a large amount of power, increases the inherent final amplifier non linearity. A method is presented for avoiding the large signal non linear analysis and it is shown how each component of the beam induced voltage depends upon all the beam harmonics via some coupling coefficients which are evaluated

  17. Pulse pressure and diabetes treatments: Blood pressure and pulse pressure difference among glucose lowering modality groups in type 2 diabetes.

    Science.gov (United States)

    Alemi, Hamid; Khaloo, Pegah; Mansournia, Mohammad Ali; Rabizadeh, Soghra; Salehi, Salome Sadat; Mirmiranpour, Hossein; Meftah, Neda; Esteghamati, Alireza; Nakhjavani, Manouchehr

    2018-02-01

    Type 2 diabetes is associated with higher pulse pressure. In this study, we assessed and compared effects of classic diabetes treatments on pulse pressure (PP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) in patients with type 2 diabetes.In a retrospective cohort study, 718 non-hypertensive patients with type 2 diabetes were selected and divided into 4 groups including metformin, insulin, glibenclamide+metformin, and metformin+insulin. They were followed for 4 consecutive visits lasting about 45.5 months. Effects of drug regimens on pulse and blood pressure over time were assessed separately and compared in regression models with generalized estimating equation method and were adjusted for age, duration of diabetes, sex, smoking, and body mass index (BMI).Studied groups had no significant change in PP, SBP, and DBP over time. No significant difference in PP and DBP among studied groups was observed (PP:P = 0.090; DBP:P = 0.063). Pairwise comparisons of PP, SBP, and DBP showed no statistically significant contrast between any 2 studied groups. Interactions of time and treatment were not different among groups.Our results demonstrate patients using metformin got higher PP and SBP over time. Averagely, pulse and blood pressure among groups were not different. Trends of variation in pulse and blood pressure were not different among studied diabetes treatments.

  18. Effect of pulse pressure on borehole stability during shear swirling flow vibration cementing.

    Directory of Open Access Journals (Sweden)

    Zhihua Cui

    Full Text Available The shear swirling flow vibration cementing (SSFVC technique rotates the downhole eccentric cascade by circulating cementing fluid. It makes the casing eccentrically revolve at high speed around the borehole axis. It produces strong agitation action to the annulus fluid, makes it in the state of shear turbulent flow, and results in the formation of pulse pressure which affects the surrounding rock stress. This study was focused on 1 the calculation of the pulse pressure in an annular turbulent flow field based on the finite volume method, and 2 the analysis of the effect of pulse pressure on borehole stability. On the upside, the pulse pressure is conducive to enhancing the liquidity of the annulus fluid, reducing the fluid gel strength, and preventing the formation of fluid from channeling. But greater pulse pressure may cause lost circulation and even formation fracturing. Therefore, in order to ensure smooth cementing during SSFVC, the effect of pulse pressure should be considered when cementing design.

  19. Does the pulse pressure in people of European, African and South Asian descent differ? A systematic review and meta-analysis of UK data

    NARCIS (Netherlands)

    Agyemang, C.; Bhopal, R.; Redekop, W. K.

    2007-01-01

    The aim of this study was to assess whether the pulse pressures (PPs) in people of African and South Asian descent differ from those of the European-origin White (henceforth, White) in the UK. A systematic literature review was carried out using MEDLINE 1966-2006 and EMBASE 1980-2006. The

  20. The effect of positive end-expiratory pressure on pulse pressure ...

    African Journals Online (AJOL)

    The effect of positive end-expiratory pressure on pulse pressure variation. FJ Smith, M Geyser, I Schreuder, PJ Becker. Abstract. Objectives: To determine the effect of different levels of positive end-expiratory pressure (PEEP) on pulse pressure variation (PPV). Design: An observational study. Setting: Operating theatres of a ...

  1. Integrated experimental test program on waterhammer pressure pulses and associated structural responses within a feedwater sparger

    International Nuclear Information System (INIS)

    Nurkkala, P.; Hoikkanen, J.

    1997-01-01

    This paper describes the methods and systems as utilized in an integrated experimental thermohydraulic/mechanics analysis test program on waterhammer pressure pulses within a revised feedwater sparger of a Loviisa generation VVER-440-type reactor. This program was carried out in two stages: (1) measurements with a strictly limited set of operating parameters at Loviisa NPP, and (2) measurements with the full set of operating parameters on a test article simulating the revised feedwater sparger. The experiments at Loviisa NPS served as an invaluable source of information on the nature of waterhammer pressure pulses and structural responses. These tests thus helped to set the objectives and formulate the concept for series of tests on a test article to study the water hammer phenomena. The heavily instrumented full size test article of a steam generator feedwater sparger was placed within a pressure vessel simulating the steam generator. The feedwater sparger was subjected to the full range of operating parameters which were to result in waterhammer pressure pulse trains of various magnitudes and duration. Two different designs of revised feedwater sparger were investigated (i.e. 'grounded' and 'with goose neck'). The following objects were to be met within this program: (1) establish the thermohydraulic parameters that facilitate the occurrence of water hammer pressure pulses, (2) provide a database for further analysis of the pressure pulse phenomena, (3) establish location and severity of these water hammer pressure pulses, (4) establish the structural response due to these pressure pulses, (5) provide input data for structural integrity analysis. (orig.)

  2. Pressure pulses generated by gas released from a breached fuel element

    International Nuclear Information System (INIS)

    Wu, T.S.

    1979-01-01

    In experimental measurements of liquid pressure pulses generated by rapid release of gas from breached fuel elements in a nuclear reactor, different peak pressures were observed at locations equidistant from the origin of the release. Using the model of a submerged spherical bubble with a nonstationary center, this analysis predicts not only that the peak pressure would be higher at a point in front of the advancing bubble than that at a point the same distance behind the bubble origin, but also that the pressure pulse in front of the bubble reaches its peak later than the pulse behind the origin

  3. Long-duration nano-second single pulse lasers for observation of spectra from bulk liquids at high hydrostatic pressures

    International Nuclear Information System (INIS)

    Thornton, Blair; Sakka, Tetsuo; Masamura, Tatsuya; Tamura, Ayaka; Takahashi, Tomoko; Matsumoto, Ayumu

    2014-01-01

    The influence of laser pulse duration on the spectral emissions observed from bulk ionic solutions has been investigated for hydrostatic pressures between 0.1 and 30 MPa. Transient pressure, shadowgraph imaging and spectroscopic measurements were performed for single pulses of duration 20 and 150 ns. The transient pressure measurements show that for hydrostatic pressures up to 30 MPa, propagation of the high-pressure shockwave generated by the focused laser causes the local pressure to reduce below ambient levels during the time frame that spectroscopic measurements can be made. The pressure impulse and subsequent reduction in pressure are larger, with the latter lasting longer for the 150 ns pulse compared to a 20 ns pulse of the same energy. The 150 ns pulse generates larger cavities with significant enhancement of the spectral emissions observed compared to the 20 ns duration pulse for pressures up to 30 MPa. The results demonstrate that laser-induced breakdown using a long ns duration pulse offers an advantage over conventional, short ns duration pulses for the analysis of bulk ionic solutions at hydrostatic pressures between 0.1 and 30 MPa. - Highlights: • Long-ns-duration laser pulses enhance the spectra observed from bulk solutions. • Laser-induced shockwaves momentarily reduce pressures to below ambient levels. • 150 ns pulses generate larger cavities than 20 ns pulses of the same energy. • Hydrostatic pressures < 30 MPa have no significant effect on the observed spectra

  4. Tensile Strength of Water Exposed to Pressure Pulses

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Mørch, Knud Aage

    2012-01-01

    at an extended water-solid interface by imposing a tensile stress pulse which easily causes cavitation. Next, a compressive pulse of duration ~1 ms and a peak intensity of a few bar is imposed prior to the tensile stress pulse. A dramatic increase of the tensile strength is observed immediately after......It is well known that pressurization for an extended period of time increases the tensile strength of water, but little information is available on the effect of pressure pulses of short duration. This is addressed in the present paper where we first measure the tensile strength of water...

  5. Tracking a Solar Wind Dynamic Pressure Pulses' Impact Through the Magnetosphere Using the Heliophysics System Observatory

    Science.gov (United States)

    Vidal-Luengo, S.; Moldwin, M.

    2017-12-01

    During northward Interplanetary Magnetic Field (IMF) Bz conditions, the magnetosphere acts as a closed "cavity" and reacts to solar wind dynamic pressure pulses more simply than during southward IMF conditions. Effects of solar wind dynamic pressure have been observed as geomagnetic lobe compressions depending on the characteristics of the pressure pulse and the spacecraft location. One of the most important aspects of this study is the incorporation of simultaneous observations by different missions, such as WIND, CLUSTER, THEMIS, MMS, Van Allen Probes and GOES as well as magnetometer ground stations that allow us to map the magnetosphere response at different locations during the propagation of a pressure pulse. In this study we used the SYM-H as an indicator of dynamic pressure pulses occurrence from 2007 to 2016. The selection criteria for events are: (1) the increase in the index must be bigger than 10 [nT] and (2) the rise time must be in less than 5 minutes. Additionally, the events must occur under northward IMF and at the same time at least one spacecraft has to be located in the magnetosphere nightside. Using this methodology we found 66 pressure pulse events for analysis. Most of them can be classified as step function pressure pulses or as sudden impulses (increase followed immediately by a decrease of the dynamic pressure). Under these two categories the results show some systematic signatures depending of the location of the spacecraft. For both kind of pressure pulse signatures, compressions are observed on the dayside. However, on the nightside compressions and/or South-then-North magnetic signatures can be observed for step function like pressure pulses, meanwhile for the sudden impulse kind of pressure pulses the magnetospheric response seems to be less global and more dependent on the local conditions.

  6. Quantitative pulsed eddy current analysis

    International Nuclear Information System (INIS)

    Morris, R.A.

    1975-01-01

    The potential of pulsed eddy current testing for furnishing more information than conventional single-frequency eddy current methods has been known for some time. However, a fundamental problem has been analyzing the pulse shape with sufficient precision to produce accurate quantitative results. Accordingly, the primary goal of this investigation was to: demonstrate ways of digitizing the short pulses encountered in PEC testing, and to develop empirical analysis techniques that would predict some of the parameters (e.g., depth) of simple types of defect. This report describes a digitizing technique using a computer and either a conventional nuclear ADC or a fast transient analyzer; the computer software used to collect and analyze pulses; and some of the results obtained. (U.S.)

  7. The impact of sedation on pulse pressure variation

    Czech Academy of Sciences Publication Activity Database

    Zvoníček, V.; Jurák, Pavel; Halámek, Josef; Kružliak, P.; Vondra, Vlastimil; Leinveber, P.; Cundrle, I.; Pavlík, M.; Suk, P.; Šrámek, V.

    2015-01-01

    Roč. 28, č. 4 (2015), s. 203-207 ISSN 1036-7314 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : pulse pressure variation * sedation * heart lung interactions * mechanical ventilation * brain death * oesophageal pressure Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.479, year: 2015

  8. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    NARCIS (Netherlands)

    L.V. Wain (Louise); G.C. Verwoert (Germaine); P.F. O'Reilly (Paul); G. Shi (Gang); T. Johnson (Toby); M. Bochud (Murielle); K. Rice (Kenneth); P. Henneman (Peter); A.V. Smith (Albert Vernon); G.B. Ehret (Georg); N. Amin (Najaf); M.G. Larson (Martin); V. Mooser (Vincent); D. Hadley (David); M. Dörr (Marcus); J.C. Bis (Joshua); T. Aspelund (Thor); T. Esko (Tõnu); A.C.J.W. Janssens (Cécile); J.H. Zhao (Jing Hua); S.C. Heath (Simon); M. Laan (Maris); J. Fu (Jingyuan); G. Pistis (Giorgio); J. Luan; G. Lucas (Gavin); N. Pirastu (Nicola); I. Pichler (Irene); A.U. Jackson (Anne); R.J. Webster (Rebecca J.); F.F. Zhang; J. Peden (John); R. Schmidt (Reinhold); T. Tanaka (Toshiko); H. Campbell (Harry); W. Igl (Wilmar); Y. Milaneschi (Yuri); J.J. Hottenga (Jouke Jan); V. Vitart (Veronique); D.I. Chasman (Daniel); S. Trompet (Stella); J.L. Bragg-Gresham (Jennifer L.); B.Z. Alizadeh (Behrooz); J.C. Chambers (John); X. Guo (Xiuqing); T. Lehtimäki (Terho); B. Kuhnel (Brigitte); L.M. Lopez; O. Polasek (Ozren); M. Boban (Mladen); C.P. Nelson (Christopher P.); A.C. Morrison (Alanna); V. Pihur (Vasyl); S.K. Ganesh (Santhi); A. Hofman (Albert); S. Kundu (Suman); F.U.S. Mattace Raso (Francesco); F. Rivadeneira Ramirez (Fernando); E.J.G. Sijbrands (Eric); A.G. Uitterlinden (André); S.J. Hwang; R.S. Vasan (Ramachandran Srini); Y.A. Wang (Ying); S.M. Bergmann (Sven); P. Vollenweider (Peter); G. Waeber (Gérard); J. Laitinen (Jaana); A. Pouta (Anneli); P. Zitting (Paavo); W.L. McArdle (Wendy); H.K. Kroemer (Heyo); U. Völker (Uwe); H. Völzke (Henry); N.L. Glazer (Nicole); K.D. Taylor (Kent); T.B. Harris (Tamara); H. Alavere (Helene); T. Haller (Toomas); A. Keis (Aime); M.L. Tammesoo; Y.S. Aulchenko (Yurii); K-T. Khaw (Kay-Tee); P. Galan (Pilar); S. Hercberg (Serge); G.M. Lathrop (Mark); S. Eyheramendy (Susana); E. Org (Elin); S. Sõber (Siim); X. Lu (Xiaowen); I.M. Nolte (Ilja); B.W.J.H. Penninx (Brenda); T. Corre (Tanguy); C. Masciullo (Corrado); C. Sala (Cinzia); L. Groop (Leif); B.F. Voight (Benjamin); O. Melander (Olle); C.J. O'Donnell (Christopher); V. Salomaa (Veikko); P. d' Adamo (Pio); A. Fabretto (Antonella); F. Faletra (Flavio); S. Ulivi (Shelia); F. Del Greco M (Fabiola); M.F. Facheris (Maurizio); F.S. Collins (Francis); R.N. Bergman (Richard); J.P. Beilby (John); J. Hung (Judy); A.W. Musk (Arthur); M. Mangino (Massimo); S.Y. Shin (So Youn); N. Soranzo (Nicole); H. Watkins (Hugh); A. Goel (Anuj); A. Hamsten (Anders); P. Gider (Pierre); M. Loitfelder (Marisa); M. Zeginigg (Marion); D.G. Hernandez (Dena); S.S. Najjar (Samer); P. Navarro (Pau); S.H. Wild (Sarah); A.M. Corsi (Anna Maria); A. Singleton (Andrew); E.J.C. de Geus (Eco); G.A.H.M. Willemsen (Gonneke); A.N. Parker (Alex); L.M. Rose (Lynda); B.M. Buckley (Brendan M.); D.J. Stott (David. J.); M. Orrù (Marco); M. Uda (Manuela); M.M. van der Klauw (Melanie); X. Li (Xiaohui); J. Scott (James); Y.D.I. Chen (Yii-Der Ida); G.L. Burke (Greg); M. Kähönen (Mika); J. Viikari (Jorma); A. Döring (Angela); T. Meitinger (Thomas); G.S. Davis; J.M. Starr (John); V. Emilsson (Valur); A.S. Plump (Andrew); J.H. Lindeman (Jan H.); P.A.C. 't Hoen (Peter); I.R. König (Inke); J.F. Felix (Janine); R. Clarke; J. Hopewell; H. Ongen (Halit); M.M.B. Breteler (Monique); S. Debette (Stéphanie); A.L. DeStefano (Anita); M. Fornage (Myriam); G.F. Mitchell (Gary); H. Holm (Hilma); K. Stefansson (Kari); G. Thorleifsson (Gudmar); U. Thorsteinsdottir (Unnur); N.J. Samani (Nilesh); M. Preuss (Michael); I. Rudan (Igor); C. Hayward (Caroline); I.J. Deary (Ian); H.E. Wichmann (Heinz Erich); O. Raitakari (Olli); W. Palmas (Walter); J.S. Kooner (Jaspal); R.P. Stolk (Ronald); J.W. Jukema (Jan Wouter); A.F. Wright (Alan); D.I. Boomsma (Dorret); S. Bandinelli (Stefania); U. Gyllensten (Ulf); J.F. Wilson (James); L. Ferrucci (Luigi); M. Farrall (Martin); T.D. Spector (Timothy); L.J. Palmer; J. Tuomilehto (Jaakko); A. Pfeufer (Arne); P. Gasparini (Paolo); D.S. Siscovick (David); D. Altshuler (David); R.J.F. Loos (Ruth); D. Toniolo (Daniela); H. Snieder (Harold); C. Gieger (Christian); P. Meneton (Pierre); N.J. Wareham (Nick); B.A. Oostra (Ben); A. Metspalu (Andres); L.J. Launer (Lenore); R. Rettig (Rainer); D.P. Strachan (David); J.S. Beckmann (Jacques); J.C.M. Witteman (Jacqueline); J.A.P. Willems van Dijk (Ko); E.A. Boerwinkle (Eric); M. Boehnke (Michael); P.M. Ridker (Paul); M.R. Järvelin; A. Chakravarti (Aravinda); J. Erdmann (Jeanette); V. Gudnason (Vilmundur); C. Newton-Cheh (Christopher); D. Levy (Daniel); P. Arora (Pankaj); P. Munroe (Patricia); B.M. Psaty (Bruce); M. Caulfield (Mark); D.C. Rao (Dabeeru C.); P. Elliott (Paul); P. Tikka-Kleemola (Päivi); G.R. Abecasis (Gonçalo); I.E. Barroso (Inês)

    2011-01-01

    textabstractNumerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N =

  9. Arterial blood pressure measurement and pulse wave analysis—their role in enhancing cardiovascular assessment

    International Nuclear Information System (INIS)

    Avolio, Alberto P; Butlin, Mark; Walsh, Andrew

    2010-01-01

    The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. (topical review)

  10. Models of brachial to finger pulse wave distortion and pressure decrement.

    Science.gov (United States)

    Gizdulich, P; Prentza, A; Wesseling, K H

    1997-03-01

    To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by the Finapres technique in 53 adult human subjects. Mean pressure was subtracted from each pressure waveform and Fourier analysis applied to the pulsations. A distortion model was estimated for each subject and averaged over the group. The average inverse model was applied to the full finger pressure waveform. The pressure decrement was modelled by multiple regression on finger systolic and diastolic levels. Waveform distortion could be described by a general, frequency dependent model having a resonance at 7.3 Hz. The general inverse model has an anti-resonance at this frequency. It converts finger to brachial pulsations thereby reducing average waveform distortion from 9.7 (s.d. 3.2) mmHg per sample for the finger pulse to 3.7 (1.7) mmHg for the converted pulse. Systolic and diastolic level differences between finger and brachial arterial pressures changed from -4 (15) and -8 (11) to +8 (14) and +8 (12) mmHg, respectively, after inverse modelling, with pulse pressures correct on average. The pressure decrement model reduced both the mean and the standard deviation of systolic and diastolic level differences to 0 (13) and 0 (8) mmHg. Diastolic differences were thus reduced most. Brachial to finger pulse wave distortion due to wave reflection in arteries is almost identical in all subjects and can be modelled by a single resonance. The pressure decrement due to flow in arteries is greatest for high pulse pressures superimposed on low means.

  11. Integrated experimental test program on waterhammer pressure pulses and associated structural responses within a feedwater sparger

    Energy Technology Data Exchange (ETDEWEB)

    Nurkkala, P.; Hoikkanen, J. [Imatran Voima Oy, Vantaa (Finland)

    1997-12-31

    This paper describes the methods and systems as utilized in an integrated experimental thermohydraulic/mechanics analysis test program on waterhammer pressure pulses within a revised feedwater sparger of a Loviisa generation VVER-440-type reactor. This program was carried out in two stages: (1) measurements with a strictly limited set of operating parameters at Loviisa NPP, and (2) measurements with the full set of operating parameters on a test article simulating the revised feedwater sparger. The experiments at Loviisa NPS served as an invaluable source of information on the nature of waterhammer pressure pulses and structural responses. These tests thus helped to set the objectives and formulate the concept for series of tests on a test article to study the water hammer phenomena. The heavily instrumented full size test article of a steam generator feedwater sparger was placed within a pressure vessel simulating the steam generator. The feedwater sparger was subjected to the full range of operating parameters which were to result in waterhammer pressure pulse trains of various magnitudes and duration. Two different designs of revised feedwater sparger were investigated (i.e. `grounded` and `with goose neck`). The following objects were to be met within this program: (1) establish the thermohydraulic parameters that facilitate the occurrence of water hammer pressure pulses, (2) provide a database for further analysis of the pressure pulse phenomena, (3) establish location and severity of these water hammer pressure pulses, (4) establish the structural response due to these pressure pulses, (5) provide input data for structural integrity analysis. (orig.). 3 refs.

  12. Integrated experimental test program on waterhammer pressure pulses and associated structural responses within a feedwater sparger

    Energy Technology Data Exchange (ETDEWEB)

    Nurkkala, P; Hoikkanen, J [Imatran Voima Oy, Vantaa (Finland)

    1998-12-31

    This paper describes the methods and systems as utilized in an integrated experimental thermohydraulic/mechanics analysis test program on waterhammer pressure pulses within a revised feedwater sparger of a Loviisa generation VVER-440-type reactor. This program was carried out in two stages: (1) measurements with a strictly limited set of operating parameters at Loviisa NPP, and (2) measurements with the full set of operating parameters on a test article simulating the revised feedwater sparger. The experiments at Loviisa NPS served as an invaluable source of information on the nature of waterhammer pressure pulses and structural responses. These tests thus helped to set the objectives and formulate the concept for series of tests on a test article to study the water hammer phenomena. The heavily instrumented full size test article of a steam generator feedwater sparger was placed within a pressure vessel simulating the steam generator. The feedwater sparger was subjected to the full range of operating parameters which were to result in waterhammer pressure pulse trains of various magnitudes and duration. Two different designs of revised feedwater sparger were investigated (i.e. `grounded` and `with goose neck`). The following objects were to be met within this program: (1) establish the thermohydraulic parameters that facilitate the occurrence of water hammer pressure pulses, (2) provide a database for further analysis of the pressure pulse phenomena, (3) establish location and severity of these water hammer pressure pulses, (4) establish the structural response due to these pressure pulses, (5) provide input data for structural integrity analysis. (orig.). 3 refs.

  13. Pulsed pressure treatment for inactivation of escherichia coli and listeria innocua in whole milk

    Energy Technology Data Exchange (ETDEWEB)

    Buzrul, S; Largeteau, A; Demazeau, G [ICMCB, CNRS, Universite Bordeaux 1, site de l' ENSCPB, 87 avenue du Dr. A. Schweitzer, 33608 PESSAC cedex (France); Alpas, H [Food Engineering Department, Middle East Technical University, 06531, Ankara (Turkey)], E-mail: sbuzrul@metu.edu.tr

    2008-07-15

    E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min x 2 pulses, 1 min x 5 pulses and 0.5 min x 10 pulses), 10 min (5 min x 2 pulses, 2 min x 5 pulses and 1 min x 10 pulses), 15 min (5 min x 3 pulses, 3 min x 5 pulses and 1.5 min x 10 pulses) and 20 min (10 min x 2 pulses, 5 min x 4 pulses, 4 min x 5 pulses and 2 min x 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms.

  14. Pulsed pressure treatment for inactivation of escherichia coli and listeria innocua in whole milk

    Science.gov (United States)

    Buzrul, S.; Largeteau, A.; Alpas, H.; Demazeau, G.

    2008-07-01

    E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min × 2 pulses, 1 min × 5 pulses and 0.5 min × 10 pulses), 10 min (5 min × 2 pulses, 2 min × 5 pulses and 1 min × 10 pulses), 15 min (5 min × 3 pulses, 3 min × 5 pulses and 1.5 min × 10 pulses) and 20 min (10 min × 2 pulses, 5 min × 4 pulses, 4 min × 5 pulses and 2 min × 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms.

  15. Pulsed pressure treatment for inactivation of escherichia coli and listeria innocua in whole milk

    International Nuclear Information System (INIS)

    Buzrul, S; Largeteau, A; Demazeau, G; Alpas, H

    2008-01-01

    E. coli and L. innocua in whole milk were subjected to continuous pressure treatments (300, 350, 400, 450, 500, 550 and 600 MPa) at ambient temperature for 5, 10, 15 and 20 min. These treatments underlined that at moderate pressure values (300, 350 and 400 MPa), increasing the pressurization time from 5 to 20 min did not improve cell death to a great extent. Therefore, pulsed pressure treatments (at 300, 350 and 400 MPa) for 5 min (2.5 min x 2 pulses, 1 min x 5 pulses and 0.5 min x 10 pulses), 10 min (5 min x 2 pulses, 2 min x 5 pulses and 1 min x 10 pulses), 15 min (5 min x 3 pulses, 3 min x 5 pulses and 1.5 min x 10 pulses) and 20 min (10 min x 2 pulses, 5 min x 4 pulses, 4 min x 5 pulses and 2 min x 10 pulses) were applied. As already observed in continuous pressure experiments, in pulsed pressure treatments the inactivation level is improved with increasing pressure level and in addition with the number of applied pulses; however, the effect of pulse number is not additive. Results obtained in this study indicated that pulsed pressure treatments could be used to pasteurize the whole milk at lower pressure values than the continuous pressure treatments. Nevertheless, an optimization appears definetely necessary between the number of pulses and pressure levels to reach the desirable number of log-reduction of microorganisms

  16. Ozone formation in pulsed SDBD in a wide pressure range

    Science.gov (United States)

    Starikovskiy, Andrey; Nudnova, Maryia; mipt Team

    2011-10-01

    Ozone concentration in surface anode-directed DBD for wide pressure range (150 - 1300 torr) was experimentally measured. Voltage and pressure effect were investigated. Reduced electric field was measured for anode-directed and cathode-directed SDBD. E/n values in cathode-directed SDBD is higher than in cathode-directed on 50 percent at atmospheric pressure. E/n value increase leads to decrease the rate of oxygen dissociation and Ozone formation at lower pressures. Radiating region thickness of sliding discharge was measured. Typical thickness of radiating zone is 0.4-1.0 mm within pressure range 220-740 torr. It was shown that high-voltage pulsed nanosecond discharge due to high E/n value produces less Ozone with compare to other discharges. Kinetic model was proposed to describe Ozone formation in the pulsed nanosecond SDBD.

  17. Prehospital shock index and pulse pressure/heart rate ratio to predict massive transfusion after severe trauma: Retrospective analysis of a large regional trauma database.

    Science.gov (United States)

    Pottecher, Julien; Ageron, François-Xavier; Fauché, Clémence; Chemla, Denis; Noll, Eric; Duranteau, Jacques; Chapiteau, Laurent; Payen, Jean-François; Bouzat, Pierre

    2016-10-01

    Early and accurate detection of severe hemorrhage is critical for a timely trigger of massive transfusion (MT). Hemodynamic indices combining heart rate (HR) and either systolic (shock index [SI]) or pulse pressure (PP) (PP/HR ratio) have been shown to track blood loss during hemorrhage. The present study assessed the accuracy of prehospital SI and PP/HR ratio to predict subsequent MT, using the gray-zone approach. This was a retrospective analysis (January 1, 2009, to December 31, 2011) of a prospectively developed trauma registry (TRENAU), in which the triage scheme combines patient severity and hospital facilities. Thresholds for MT were defined as either classic (≥10 red blood cell units within the first 24 hours [MT1]) or critical (≥3 red blood cells within the first hour [MT2]). The receiver operating characteristic curves and gray zones were defined for SI and PP/HR ratio to predict MT1 and MT2 and faced with initial triage scheme. The TRENAU registry included 3,689 trauma patients, of which 2,557 had complete chart recovery and 176 (6.9%) required MT. In the whole population, PP/HR ratio and SI moderately and similarly predicted MT1 (area under the receiver operating characteristic curve, 0.77 [95% confidence interval {CI}, 0.70-0.84] and 0.80 [95% CI, 0.74-0.87], respectively, p = 0.064) and MT2 (0.71 [95% CI, 0.67-0.76] and 0.72 [95% CI, 0.68-0.77], respectively, p = 0.48). The proportions of patients in the gray zone for PP/HR ratio and SI were 61% versus 40%, respectively, to predict MT1 (p ratio outperformed SI to predict MT2 (0.72 [95% CI, 0.59-0.84] vs. 0.54 [95% CI, 0.33-0.74]; p ratio were moderately accurate in predicting MT. In the seemingly least severe patients, an improvement of prehospital undertriage for MT may be gained by using the PP/HR ratio. Epidemiolgic study, level III.

  18. Piston cylinder cell for high pressure ultrasonic pulse echo measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kepa, M. W., E-mail: mkepa@staffmail.ed.ac.uk; Huxley, A. D. [SUPA, Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Ridley, C. J.; Kamenev, K. V. [Centre for Science at Extreme Conditions and School of Engineering, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)

    2016-08-15

    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe{sub 2}.

  19. Pulsed operation of high-pressure-sodium discharge lamps

    International Nuclear Information System (INIS)

    Guenther, K.; Kloss, H.G.; Lehmann, T.; Radtke, R.; Serick, F.

    1990-01-01

    Results of spectral and photometric measurements are presented for pulsed operated high-pressure-sodium lamps. Choosing for the colour temperature a value of 3000 K, the output spectrum was optimized with respect to colour rendition and lamp efficacy taking the pulse parameters, the sodium mole fraction, and the cold spot temperature as quantities to be varied. For the nominal rating of 70 W a maximum lamp efficacy of 70 lm/W and a colour rendering index of 40 can be obtained. Further improvements of the colour rendition require an enhanced sodium vapour pressure which can be achieved by operating the lamp at rised cold spot temperature. (orig.)

  20. Pulsed operation of high-pressure-sodium discharge lamps

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, K; Kloss, H G; Lehmann, T [Zentrum fuer Forschung und Technologie, Berlin (Germany, F.R.); Radtke, R; Serick, F [Zentralinstitut fuer Elektronenphysik, Berlin (Germany, F.R.)

    1990-01-01

    Results of spectral and photometric measurements are presented for pulsed operated high-pressure-sodium lamps. Choosing for the colour temperature a value of 3000 K, the output spectrum was optimized with respect to colour rendition and lamp efficacy taking the pulse parameters, the sodium mole fraction, and the cold spot temperature as quantities to be varied. For the nominal rating of 70 W a maximum lamp efficacy of 70 lm/W and a colour rendering index of 40 can be obtained. Further improvements of the colour rendition require an enhanced sodium vapour pressure which can be achieved by operating the lamp at rised cold spot temperature. (orig.).

  1. Measuring sub-bandage pressure: comparing the use of pressure monitors and pulse oximeters.

    Science.gov (United States)

    Satpathy, A; Hayes, S; Dodds, S R

    2006-03-01

    To test the use of low-cost sub-bandage pressure monitors and pulse oximeters as part of a quality-control measure for graduated compression bandaging in leg ulcer clinics. Twenty-five healthy volunteers (mean age 40 years) providing 50 limbs were bandaged with a four-layer compression bandaging system. The ankle systolic pressure (ASP) was measured using a pulse oximeter (Nellcor NBP-40) before applying the graduated compression bandages. Interface pressure was measured by placing pressure sensors on the skin at three points (2cm above the medial malleolus; the widest part of the calf; and a point midway between them) in the supine and standing positions. The ASP was measured again with the pulse oximeter after the bandage had been applied, and the effect of the bandage on the ASP was recorded. The actual pressure created by the bandage was compared with the required pressure profile. Interface pressures varied with change of position and movement. With the operator blinded to the pressure monitors while applying the bandages, the target pressure of 35-40mmHg at the ankle was achieved in only 36% of limbs ([mean +/- 95% confidence interval]; 32.3 +/- 1.6mmHg [supine]; 38.4 +/- 2.4mmHg [standing position]). With the help of the pressure monitors, the target pressure was achieved in 78% of the limbs. There was no correlation between the pressure monitors and pulse oximeter pressures, demonstrating that the pulse oximeter is not a useful tool for measuring sub-bandage pressures. The results suggest a tool (interface pressure monitors) that is easy to operate should be available as part of quality assurance for treatment, training of care providers and education.

  2. Pressure heat pumping in the orifice pulse-tube refrigerator

    International Nuclear Information System (INIS)

    Boer, P.C.T. de

    1996-01-01

    The mechanism by which heat is pumped as a result of pressure changes in an orifice pulse-tube refrigerator (OPTR) is analyzed thermodynamically. The thermodynamic cycle considered consists of four steps: (1) the pressure is increased by a factor π 1 due to motion of a piston in the heat exchanger at the warm end of the regenerator; (2) the pressure is decreased by a factor π 2 due to leakage out of the orifice; (3) the pressure is further decreased due to motion of the piston back to its original position; (4) the pressure is increased to its value at the start of the cycle due to leakage through the orifice back into the pulse tube. The regenerator and the heat exchangers are taken to be perfect. The pressure is assumed to be uniform during the entire cycle. The temperature profiles of the gas in the pulse tube after each step are derived analytically. Knowledge of the temperature at which gas enters the cold heat exchanger during steps 3 and 4 provides the heat removed per cycle from this exchanger. Knowledge of the pressure as a function of piston position provides the work done per cycle by the piston. The pressure heat pumping mechanism considered is effective only in the presence of a regenerator. Detailed results are presented for the heat removed per cycle, for the coefficient of performance, and for the refrigeration efficiency as a function of the compression ratio π 1 and the expansion ratio π 2 . Results are also given for the influence on performance of the ratio of specific heats. The results obtained are compared with corresponding results for the basic pulse-tube refrigerator (BPTR) operating by surface heat pumping

  3. Viscoelastic fingering with a pulsed pressure signal

    International Nuclear Information System (INIS)

    Corvera Poire, E; Rio, J A del

    2004-01-01

    We derive a generalized Darcy's law in the frequency domain for a linear viscoelastic fluid flowing in a Hele-Shaw cell. This leads to an analytic expression for the dynamic permeability that has maxima which are several orders of magnitude larger than the static permeability. We then follow an argument of de Gennes (1987 Europhys. Lett. 2 195) to obtain the smallest possible finger width when viscoelasticity is important. Using this and a conservation law, we obtain the lowest bound for the width of a single finger displacing a viscoelastic fluid. When the driving force consists of a constant pressure gradient plus an oscillatory signal, our results indicate that the finger width varies in time following the frequency of the incident signal. Also, the amplitude of the finger width in time depends on the value of the dynamic permeability at the imposed frequency. When the finger is driven with a frequency that maximizes the permeability, variations in the amplitude are also maximized. This gives results that are very different for Newtonian and viscoelastic fluids. For the former ones the amplitude of the oscillation decays with frequency. For the latter ones on the other hand, the amplitude has maxima at the same frequencies that maximize the dynamic permeability

  4. Fluctuation of blood pressure and pulse rate during colostomy irrigation.

    Science.gov (United States)

    Sadahiro, S; Noto, T; Tajima, T; Mitomi, T; Miyazaki, T; Numata, M

    1995-06-01

    The aim of this study was to determine the effects of colostomy irrigation on the vital signs of patients with left colostomy. Twenty-two consecutive patients who underwent abdominoperineal resection for cancer of the lower rectum and had left lower quadrant end colostomy were included in this study. Subjective symptoms, blood pressure, and pulse rate during the first irrigation were investigated. Fluctuation of blood pressure during instillation was 8.0/8.5 mmHg (average) and 25.0/17.9 mmHg during evacuation. Fluctuation of pulse rate was 5.5 per minute (average) during instillation and 11.5 per minute during evacuation. The number of subjects who showed more than 20% fluctuation of systolic pressure was 12 (54.5 percent) and that of diastolic pressure was 14 (63.6 percent). One of 22 patients complained of illness during irrigation. Although colostomy irrigation showed no significant effects on vital signs in the majority of patients, it caused a significant reduction in both blood pressure and pulse rate in a small number of patients. Careful attention should be paid to vital signs considering the possibility of such effects, especially on the initial irrigation.

  5. Numerical simulation of the pressure pulses produced by a pressure screen foil rotor

    International Nuclear Information System (INIS)

    Feng, M.; Ollivier-Gooch, C.; Gooding, R.W.; Olson, J.A.

    2003-01-01

    Pressure screening is the most industrially efficient and effective means of removing contaminants that degrade the appearance and strength of paper and fractionating fibres for selective treatments and specialty products. A critical design component of a screen is the rotor which produces pressure pulses on the screen cylinder surface to keep the screening apertures clear. To understand the effect of the key design and operating variables for a NACA 0012 foil rotor, a computational fluid dynamic (CFD) simulation tool was developed with FLUENT software, and the numerical results were compared with experimental measurements. The computational results of pressure pulses were shown to be in good agreement with experimental pressure measurements over a wide range of foil tip-speeds, clearances and angles of attack. In addition, it was shown that the magnitude of the pressure pulse peak increases as the rotating speed increases linearly with the square of tip-speed for all the angles of attack studied. The maximum negative pressure pulse occurred for the foil at 5 degrees angle of attack. Flow began to separate from foil surface near the screen plate beyond 10 degrees angle of attack. The positive pressure peak near the leading edge of the foil is completely eliminated for foils operating at a positive angle of attack. The magnitude of the negative pressure peak increased as clearance decreased. In addition to, and more important than, these specific results, we have shown that CFD is a viable tool for the optimal design and operation of rotors in industrial pressure screens. (author)

  6. Differing prognostic value of pulse pressure in patients with heart failure with reduced or preserved ejection fraction

    DEFF Research Database (Denmark)

    Jackson, Colette E; Castagno, Davide; Maggioni, Aldo P

    2015-01-01

    ) and 5008 with HF-PEF (828 deaths). Pulse pressure was analysed in quintiles in a multivariable model adjusted for the previously reported Meta-Analysis Global Group in Chronic Heart Failure prognostic variables. Heart failure and reduced ejection fraction patients in the lowest pulse pressure quintile had...... in patients with HF-PEF [ejection fraction (EF) ≥ 50%] and HF-REF. METHODS AND RESULTS: Data from 22 HF studies were examined. Preserved left ventricular ejection fraction (LVEF) was defined as LVEF ≥ 50%. All-cause mortality at 3 years was evaluated in 27 046 patients: 22 038 with HF-REF (4980 deaths......AIMS: Low pulse pressure is a marker of adverse outcome in patients with heart failure (HF) and reduced ejection fraction (HF-REF) but the prognostic value of pulse pressure in patients with HF and preserved ejection fraction (HF-PEF) is unknown. We examined the prognostic value of pulse pressure...

  7. Temporal evolution of atmosphere pressure plasma jets driven by microsecond pulses with positive and negative polarities

    Science.gov (United States)

    Shao, Tao; Yang, Wenjin; Zhang, Cheng; Fang, Zhi; Zhou, Yixiao; Schamiloglu, Edl

    2014-09-01

    Current-voltage characteristics, discharge images, and optical spectra of atmospheric pressure plasma jets (APPJs) are studied using a microsecond pulse length generator producing repetitive output pulses with different polarities. The experimental results show that the APPJs excited by the pulses with positive polarity have longer plume, faster propagation speed, higher power, and more excited species, such as \\text{N}2 , O, He, \\text{N}2+ , than that with the negatively excited APPJs. The images taken using an intensified charge-coupled device show that the APPJs excited by pulses with positive polarity are characterized by a bullet-like structure, while the APPJs excited by pulses with negative polarity are continuous. The propagation speed of the APPJs driven by a microsecond pulse length generator is about tens of km/s, which is similar to the APPJs driven by a kHz frequency sinusoidal voltage source. The analysis shows that the space charge accumulation effect plays an important role during the discharge. The transient enhanced electric field induced by the accumulated ions between the needle-like electrode and the nozzle in the APPJs excited by pulses with negative polarity enhances electron field emission from the cathode, which is illustrated by the bright line on the time-integrated images. This makes the shape of the APPJ excited using pulses with negative polarity different from the bullet-like shape of the APPJs excited by pulses with positive polarity.

  8. Effects of oxygen gas pressure on properties of iron oxide films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Guo, Qixin; Shi, Wangzhou; Liu, Feng; Arita, Makoto; Ikoma, Yoshifumi; Saito, Katsuhiko; Tanaka, Tooru; Nishio, Mitsuhiro

    2013-01-01

    Highlights: ► Pulsed laser deposition is a promising technique for growing iron oxide films. ► Crystal structure of the iron oxide films strongly depends on oxygen gas pressure. ► Optimum of the oxygen gas pressure leads single phase magnetite films with high crystal quality. -- Abstract: Iron oxide films were grown on sapphire substrates by pulsed laser deposition at oxygen gas pressures between 1 × 10 −5 and 1 × 10 −1 Pa with a substrate temperature of 600 °C. Atomic force microscope, X-ray diffraction, Raman spectroscopy, X-ray absorption fine structure, and vibrational sample magnetometer analysis revealed that surface morphology and crystal structure of the iron oxide films strongly depend on the oxygen gas pressure during the growth and the optimum oxygen gas pressure range is very narrow around 1 × 10 −3 Pa for obtaining single phase magnetite films with high crystal quality

  9. FEASIBILITY STUDY OF PRESSURE PULSING PIPELINE UNPLUGGING TECHNOLOGIES FOR HANFORD

    Energy Technology Data Exchange (ETDEWEB)

    Servin, M. A. [Washington River Protection Solutions, LLC, Richland, WA (United States); Garfield, J. S. [AEM Consulting, LLC (United States); Golcar, G. R. [AEM Consulting, LLC (United States)

    2012-12-20

    The ability to unplug key waste transfer routes is generally essential for successful tank farms operations. All transfer lines run the risk of plugging but the cross site transfer line poses increased risk due to its longer length. The loss of a transfer route needed to support the waste feed delivery mission impacts the cost and schedule of the Hanford clean up mission. This report addresses the engineering feasibility for two pressure pulse technologies, which are similar in concept, for pipeline unplugging.

  10. Feasibility Study Of Pressure Pulsing Pipeline Unplugging Technologies For Hanford

    International Nuclear Information System (INIS)

    Servin, M. A.; Garfield, J. S.; Golcar, G. R.

    2012-01-01

    The ability to unplug key waste transfer routes is generally essential for successful tank farms operations. All transfer lines run the risk of plugging but the cross site transfer line poses increased risk due to its longer length. The loss of a transfer route needed to support the waste feed delivery mission impacts the cost and schedule of the Hanford clean up mission. This report addresses the engineering feasibility for two pressure pulse technologies, which are similar in concept, for pipeline unplugging

  11. Association of pulse wave velocity and pulse pressure with decline in kidney function.

    Science.gov (United States)

    Kim, Chang Seong; Kim, Ha Yeon; Kang, Yong Un; Choi, Joon Seok; Bae, Eun Hui; Ma, Seong Kwon; Kim, Soo Wan

    2014-05-01

    The association between arterial stiffness and decline in kidney function in patients with mild to moderate chronic kidney disease (CKD) is not well established. This study investigated whether pulse wave velocity (PWV) and pulse pressure (PP) are independently associated with glomerular filtration rate (GFR) and rapid decline in kidney function in early CKD. Carotid femoral PWV (cfPWV), brachial-ankle PWV (baPWV), and PP were measured in a cohort of 913 patients (mean age, 63±10 years; baseline estimated GFR, 84±18 mL/min/1.73 m(2) ). Estimated GFR was measured at baseline and at follow-up. The renal outcome examined was rapid decline in kidney function (estimated GFR loss, >3 mL/min/1.73 m(2) per year). The median follow-up duration was 3.2 years. Multivariable adjusted linear regression model indicated that arterial PWV (both cfPWV and baPWV) and PP increased as estimated GFR declined, but neither was associated with kidney function after adjustment for various covariates. Multivariable logistic regression analysis found that cfPWV and baPWV were not associated with rapid decline in kidney function (odds ratio [OR], 1.39, 95% confidence interval [CI], 0.41-4.65; OR, 2.51, 95% CI, 0.66-9.46, respectively), but PP was (OR, 1.22, 95% CI, 1.01-1.48; P=.045). Arterial stiffness assessed using cfPWV and baPWV was not correlated with lower estimated GFR and rapid decline in kidney function after adjustment for various confounders. Thus, PP is an independent risk factor for rapid decline in kidney function in populations with relatively preserved kidney function (estimated GFR ≥30 mL/min/1.73 m(2) ). ©2014 Wiley Periodicals, Inc.

  12. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Abhay B. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Kalange, Ashok E. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Tuljaram Chaturchand College, Baramati 413 102 (India); Bodas, Dhananjay, E-mail: dhananjay.bodas@gmail.co [Center for Nanobio Sciences, Agharkar Research Institute, Pune 411 004 (India); Gangal, S.A. [Department of Electronic Science, University of Pune, Pune 411 007 (India)

    2010-04-15

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  13. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    International Nuclear Information System (INIS)

    Joshi, Abhay B.; Kalange, Ashok E.; Bodas, Dhananjay; Gangal, S.A.

    2010-01-01

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  14. Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

    Science.gov (United States)

    Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

    2009-06-01

    Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

  15. Relationship between Resting Heart Rate, Blood Pressure and Pulse Pressure in Adolescents.

    Science.gov (United States)

    Christofaro, Diego Giulliano Destro; Casonatto, Juliano; Vanderlei, Luiz Carlos Marques; Cucato, Gabriel Grizzo; Dias, Raphael Mendes Ritti

    2017-05-01

    High resting heart rate is considered an important factor for increasing mortality chance in adults. However, it remains unclear whether the observed associations would remain after adjustment for confounders in adolescents. To analyze the relationship between resting heart rate, blood pressure and pulse pressure in adolescents of both sexes. A cross-sectional study with 1231 adolescents (716 girls and 515 boys) aged 14-17 years. Heart rate, blood pressure and pulse pressure were evaluated using an oscillometric blood pressure device, validated for this population. Weight and height were measured with an electronic scale and a stadiometer, respectively, and waist circumference with a non-elastic tape. Multivariate analysis using linear regression investigated the relationship between resting heart rate and blood pressure and pulse pressure in boys and girls, controlling for general and abdominal obesity. Higher resting heart rate values were observed in girls (80.1 ± 11.0 beats/min) compared to boys (75.9 ± 12.7 beats/min) (p ≤ 0.001). Resting heart rate was associated with systolic blood pressure in boys (Beta = 0.15 [0.04; 0.26]) and girls (Beta = 0.24 [0.16; 0.33]), with diastolic blood pressure in boys (Beta = 0.50 [0.37; 0.64]) and girls (Beta = 0.41 [0.30; 0.53]), and with pulse pressure in boys (Beta = -0.16 [-0.27; -0.04]). This study demonstrated a relationship between elevated resting heart rate and increased systolic and diastolic blood pressure in both sexes and pulse pressure in boys even after controlling for potential confounders, such as general and abdominal obesity. A frequência cardíaca de repouso é considerada um importante fator de aumento de mortalidade em adultos. Entretanto, ainda é incerto se as associações observadas permanecem após ajuste para fatores de confusão em adolescentes. Analisar a relação entre frequência cardíaca de repouso, pressão arterial e pressão de pulso em adolescentes dos dois sexos. Estudo transversal

  16. Abdominal Obesity Is Characterized by Higher Pulse Pressure: Possible Role of Free Triiodothyronine

    Directory of Open Access Journals (Sweden)

    Giovanni De Pergola

    2012-01-01

    Full Text Available Objective. This study examined whether obesity is characterized by higher 24 h mean pulse pressure (24 h mean SBP-24 h mean DBP and whether free thyroid hormones (FT3 and FT4 have a relationship with 24 h mean pulse pressure. Methods. A total of 231 euthyroid overweight and obese patients, 103 women and 128 men, aged 18–68 yrs, normotensive ( or with recently developed hypertension (, never treated with antihypertensive drugs, were investigated. Fasting insulin, TSH, FT3, FT4, glucose, and lipid serum concentrations were measured. Waist circumference was measured as an indirect parameter of central fat accumulation. Ambulatory blood pressure monitoring (ABPM was performed. Results. 24 h mean pulse pressure (PP showed a significant positive correlation with BMI (, waist circumference (, and FT3 ( and insulin serum levels (. When a multivariate analysis was performed, and 24 h PP was considered as the dependent variable, and waist circumference, FT3, insulin, male sex, and age as independent parameters, 24 h mean PP maintained a significant association only with waist circumference ( and FT3 levels (. Conclusion. Our results suggest that FT3 per se may contribute to higher pulse pressure in obese subjects.

  17. Vasodilation increases pulse pressure variation, mimicking hypovolemic status in rabbits

    Directory of Open Access Journals (Sweden)

    Glauco A Westphal

    2010-01-01

    Full Text Available OBJECTIVE: To test the hypothesis that pulse pressure respiratory variation (PPV amplification, observed in hypovolemia, can also be observed during sodium nitroprusside (SNP-induced vasodilation. INTRODUCTION: PPV is largely used for early identification of cardiac responsiveness, especially when hypovolemia is suspected. PPV results from respiratory variation in transpulmonary blood flow and reflects the left ventricular preload variations during respiratory cycles. Any factor that decreases left ventricular preload can be associated with PPV amplification, as seen in hypovolemia. METHODS: Ten anesthetized and mechanically ventilated rabbits underwent progressive hypotension by either controlled hemorrhage (Group 1 or intravenous SNP infusion (Group 2. Animals in Group 1 (n = 5 had graded hemorrhage induced at 10% steps until 50% of the total volume was bled. Mean arterial pressure (MAP steps were registered and assumed as pressure targets to be reached in Group 2. Group 2 (n = 5 was subjected to a progressive SNP infusion to reach similar pressure targets as those defined in Group 1. Heart rate (HR, systolic pressure variation (SPV and PPV were measured at each MAP step, and the values were compared between the groups. RESULTS: SPV and PPV were similar between the experimental models in all steps (p > 0.16. SPV increased earlier in Group 2. CONCLUSION: Both pharmacologic vasodilation and graded hemorrhage induced PPV amplification similar to that observed in hypovolemia, reinforcing the idea that amplified arterial pressure variation does not necessarily represent hypovolemic status but rather potential cardiovascular responsiveness to fluid infusion.

  18. Multi-Pulsed High Hydrostatic Pressure Treatment of Foods

    Directory of Open Access Journals (Sweden)

    Sencer Buzrul

    2015-05-01

    Full Text Available Multi-pulsed high hydrostatic pressure (mpHHP treatment of foods has been investigated for more than two decades. It was reported that the mpHHP treatment, with few exceptions, is more effective than the classical or single-pulsed HHP (spHHP treatment for inactivation of microorganisms in fruit juice, dairy products, liquid whole egg, meat products, and sea foods. Moreover, the mpHHP treatment could be also used to inactivate enzymes in foods and to increase the shelf-life of foods. The effects of the mpHHP treatment of foods are summarized and the differences between the mpHHP and spHHP are also emphasized.

  19. Measurement of the pressure pulse from a detonating explosive

    International Nuclear Information System (INIS)

    Bourne, N K; Milne, A M; Biers, R A

    2005-01-01

    A series of experiments has been carried out to determine the pressure pulse exiting from a polymethylmethacrylate (PMMA) plate, of varying thickness, subject to the shock pulse exerted by a detonating charge of fixed mass. This calibration will define a new donor explosive and inert gap material for use in one of the qualification tests for energetic materials, the large scale gap test. The peak pressure was recorded on the central axis of the attenuator using calibrated piezoresistive manganin gauges as a function of the quantity of PMMA applied to the output of the donor charge. The stress history within the PMMA was measured as a function of run distance and the peak pressure plotted against thickness as a calibration. The shock front was known to have curvature and a measurement of this was attempted. The behaviour of the transmitted shock at small gap thicknesses was shown to be anomalous since the front was partially in a reactive and partially within an inert medium

  20. Computation of the effect of pipe plasticity on pressure-pulse propagation in a fluid system

    International Nuclear Information System (INIS)

    Youngdahl, C.K.; Kot, C.A.

    1975-04-01

    A simple computational model is developed for incorporating the effect of elastic-plastic deformation of piping on pressure-transient propagation in a fluid system. A computer program (PLWV) is described that incorporates this structural interaction model into a one-dimensional method-of-characteristics procedure for fluid-hammer analysis. Computed results are shown to be in good agreement with available experimental data. The most significant effect of plastic deformation is to limit the peak pressure of a pulse leaving a pipe to approximately the yield pressure of the pipe, if the pipe is sufficiently long. 7 references. (U.S.)

  1. On random pressure pulses in the turbine draft tube

    Science.gov (United States)

    Kuibin, P. A.; Shtork, S. I.; Skripkin, S. G.; Tsoy, M. A.

    2017-04-01

    The flow in the conical part of the hydroturbine draft tube undergoes various instabilities due to deceleration and flow swirling at off-design operation points. In particular, the precessing vortex rope develops at part-load regimes in the draft tube. This rope induces periodical low-frequency pressure oscillations in the draft tube. Interaction of rotational (asynchronous) mode of disturbances with the elbow can bring to strong oscillations in the whole hydrodynamical system. Recent researches on flow structure in the discharge cone in a regime of free runner had revealed that helical-like vortex rope can be unstable itself. Some coils of helix close to each other and reconnection appears with generation of a vortex ring. The vortex ring moves toward the draft tube wall and downstream. The present research is focused on interaction of vortex ring with wall and generation of pressure pulses.

  2. Systolic Blood Pressure Accuracy Enhancement in the Electronic Palpation Method Using Pulse Waveform

    National Research Council Canada - National Science Library

    Sorvoja, H

    2001-01-01

    .... Systolic pressure errors were defined and correlations with other specific values, like pressure rise time, pulse wave velocity, systolic pressure, augmentation, arm circumference and body mass index were calculated...

  3. Carbon dioxide reforming of methane by atmospheric pressure pulsed glow discharge: The effect of pulse compression

    International Nuclear Information System (INIS)

    Ghorbanzadeh, A.; Modarresi, H.

    2006-01-01

    Methane reforming by carbon dioxide in atmospheric pressure pulsed glow discharge was examined. The pulse duration of plasma was compressed to ∼50 ns or lower. This compression allowed working at higher frequencies, more than 3 k Hz, without glow to arc transition. The main outlet gases were synthetic gases (H 2 , CO) and C 2 (ethylene, ethane, and acetylene) products. At equal reactants proportion CO 2 /CH 4 =1, about 42 p ercent o f plasma energy went to chemical dissociation while reactant conversions were relatively high, i.e. near 55 p ercent % (CH 4 ) and 42 p ercent ( CO 2 ). At this point, the energy expenditure was less than 3.8 eV per each converted molecule. The reactor energy performance even gets better at higher CO 2 /CH 4 proportions. At CO 2 /CH 4 =5, The conversions of about 65 p ercent a nd 45 p ercent w ere obtained for methane and carbon dioxide respectively, while energy efficiency reached near 45 p ercent . It is discussed that high nonequilibrium state of vibrational energy at short pulses, especially in carbon dioxide, leads to this improvement.

  4. On the propagation of the pressure pulse due to an unconfined gas cloud explosion

    International Nuclear Information System (INIS)

    Essers, J.A.

    1985-01-01

    A critical analysis of flow models used in computer codes for the simulation of the propagation in air of a pressure pulse due to a gas cloud explosion is presented. In particular, weaknesses of simple linear acoustic model are pointed out, and a more reliable non-linear isentropic model is proposed. A simple one-dimensional theory is used to evaluate as a function of the relative overpressure the speed of an incident normal shock-wave, as well as the strength and speed of the wave after reflection on a simplified rigid obstacle. Results obtained with the different models are compared to those obtained from the full Euler equations. A theoretical analysis of pulse deformation during its propagation is presented, and the ability of each model to correctly simulate that purely non-linear phenomenon is discussed. In particular, the formation of a sharp pressure pulse (shock-up phenomenon) is analyzed in detail. From the analysis, the accuracy of the linear acoustic model for the evaluation of strength and speed of incident and reflected waves is found to be quite poor except for very weak overpressures. Additionally, such a model is completely unable to simulate pulse deformations. As a result, it should be expected to lead to important errors in the simulation of pulse interaction with non-rigid obstacles, even at very weak overpressures. As opposed to that very simple model, the proposed non-linear isentropic model is found to lead to an excellent accuracy in the prediction of all wave characteristics mentioned above and in the simulation of pulse deformation if overpressure is not too large. (author)

  5. Pulmonary artery pulse pressure and wave reflection in chronic pulmonary thromboembolism and primary pulmonary hypertension.

    Science.gov (United States)

    Castelain, V; Hervé, P; Lecarpentier, Y; Duroux, P; Simonneau, G; Chemla, D

    2001-03-15

    The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH). Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform. High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), deltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (deltaP/PPAP). At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m2), mean PAP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01). Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload.

  6. Pulsed microwave discharge at atmospheric pressure for NOx decomposition

    International Nuclear Information System (INIS)

    Baeva, M; Gier, H; Pott, A; Uhlenbusch, J; Hoeschele, J; Steinwandel, J

    2002-01-01

    A 3.0 GHz pulsed microwave source operated at atmospheric pressure with a pulse power of 1.4 MW, a maximum repetition rate of 40 Hz, and a pulse length of 3.5 μs is experimentally studied with respect to the ability to remove NO x from synthetic exhaust gases. Experiments in gas mixtures containing N 2 /O 2 /NO with typically 500 ppm NO are carried out. The discharge is embedded in a high-Q microwave resonator, which provides a reliable plasma ignition. Vortex flow is applied to the exhaust gas to improve gas treatment. Concentration measurements by Fourier transform infrared spectroscopy confirm an NO x reduction of more than 90% in the case of N 2 /NO mixtures. The admixture of oxygen lowers the reductive potential of the reactor, but NO x reduction can still be observed up to 9% O 2 concentration. Coherent anti-Stokes Raman scattering technique is applied to measure the vibrational and rotational temperature of N 2 . Gas temperatures of about 400 K are found, whilst the vibrational temperature is 3000-3500 K in pure N 2 . The vibrational temperature drops to 1500 K when O 2 and/or NO are present. The randomly distributed relative frequency of occurrence of selected breakdown field intensities is measured by a calibrated, short linear-antenna. The breakdown field strength in pure N 2 amounts to 2.2x10 6 V m -1 , a value that is reproducible within 2%. In the case of O 2 and/or NO admixture, the frequency distribution of the breakdown field strength scatters more and extends over a range from 3 to 8x10 6 V m -1

  7. Pulsed, atmospheric pressure plasma source for emission spectrometry

    Science.gov (United States)

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2004-05-11

    A low-power, plasma source-based, portable molecular light emission generator/detector employing an atmospheric pressure pulsed-plasma for molecular fragmentation and excitation is described. The average power required for the operation of the plasma is between 0.02 W and 5 W. The features of the optical emission spectra obtained with the pulsed plasma source are significantly different from those obtained with direct current (dc) discharge higher power; for example, strong CH emission at 431.2 nm which is only weakly observed with dc plasma sources was observed, and the intense CN emission observed at 383-388 nm using dc plasma sources was weak in most cases. Strong CN emission was only observed using the present apparatus when compounds containing nitrogen, such as aniline were employed as samples. The present apparatus detects dimethylsulfoxide at 200 ppb using helium as the plasma gas by observing the emission band of the CH radical. When coupled with a gas chromatograph for separating components present in a sample to be analyzed, the present invention provides an apparatus for detecting the arrival of a particular component in the sample at the end of the chromatographic column and the identity thereof.

  8. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    Science.gov (United States)

    Li, Lee; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-01

    Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

  9. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    Science.gov (United States)

    Wain, Louise V; Verwoert, Germaine C; O’Reilly, Paul F; Shi, Gang; Johnson, Toby; Johnson, Andrew D; Bochud, Murielle; Rice, Kenneth M; Henneman, Peter; Smith, Albert V; Ehret, Georg B; Amin, Najaf; Larson, Martin G; Mooser, Vincent; Hadley, David; Dörr, Marcus; Bis, Joshua C; Aspelund, Thor; Esko, Tõnu; Janssens, A Cecile JW; Zhao, Jing Hua; Heath, Simon; Laan, Maris; Fu, Jingyuan; Pistis, Giorgio; Luan, Jian’an; Arora, Pankaj; Lucas, Gavin; Pirastu, Nicola; Pichler, Irene; Jackson, Anne U; Webster, Rebecca J; Zhang, Feng; Peden, John F; Schmidt, Helena; Tanaka, Toshiko; Campbell, Harry; Igl, Wilmar; Milaneschi, Yuri; Hotteng, Jouke-Jan; Vitart, Veronique; Chasman, Daniel I; Trompet, Stella; Bragg-Gresham, Jennifer L; Alizadeh, Behrooz Z; Chambers, John C; Guo, Xiuqing; Lehtimäki, Terho; Kühnel, Brigitte; Lopez, Lorna M; Polašek, Ozren; Boban, Mladen; Nelson, Christopher P; Morrison, Alanna C; Pihur, Vasyl; Ganesh, Santhi K; Hofman, Albert; Kundu, Suman; Mattace-Raso, Francesco US; Rivadeneira, Fernando; Sijbrands, Eric JG; Uitterlinden, Andre G; Hwang, Shih-Jen; Vasan, Ramachandran S; Wang, Thomas J; Bergmann, Sven; Vollenweider, Peter; Waeber, Gérard; Laitinen, Jaana; Pouta, Anneli; Zitting, Paavo; McArdle, Wendy L; Kroemer, Heyo K; Völker, Uwe; Völzke, Henry; Glazer, Nicole L; Taylor, Kent D; Harris, Tamara B; Alavere, Helene; Haller, Toomas; Keis, Aime; Tammesoo, Mari-Liis; Aulchenko, Yurii; Barroso, Inês; Khaw, Kay-Tee; Galan, Pilar; Hercberg, Serge; Lathrop, Mark; Eyheramendy, Susana; Org, Elin; Sõber, Siim; Lu, Xiaowen; Nolte, Ilja M; Penninx, Brenda W; Corre, Tanguy; Masciullo, Corrado; Sala, Cinzia; Groop, Leif; Voight, Benjamin F; Melander, Olle; O’Donnell, Christopher J; Salomaa, Veikko; d’Adamo, Adamo Pio; Fabretto, Antonella; Faletra, Flavio; Ulivi, Sheila; Del Greco, M Fabiola; Facheris, Maurizio; Collins, Francis S; Bergman, Richard N; Beilby, John P; Hung, Joseph; Musk, A William; Mangino, Massimo; Shin, So-Youn; Soranzo, Nicole; Watkins, Hugh; Goel, Anuj; Hamsten, Anders; Gider, Pierre; Loitfelder, Marisa; Zeginigg, Marion; Hernandez, Dena; Najjar, Samer S; Navarro, Pau; Wild, Sarah H; Corsi, Anna Maria; Singleton, Andrew; de Geus, Eco JC; Willemsen, Gonneke; Parker, Alex N; Rose, Lynda M; Buckley, Brendan; Stott, David; Orru, Marco; Uda, Manuela; van der Klauw, Melanie M; Zhang, Weihua; Li, Xinzhong; Scott, James; Chen, Yii-Der Ida; Burke, Gregory L; Kähönen, Mika; Viikari, Jorma; Döring, Angela; Meitinger, Thomas; Davies, Gail; Starr, John M; Emilsson, Valur; Plump, Andrew; Lindeman, Jan H; ’t Hoen, Peter AC; König, Inke R; Felix, Janine F; Clarke, Robert; Hopewell, Jemma C; Ongen, Halit; Breteler, Monique; Debette, Stéphanie; DeStefano, Anita L; Fornage, Myriam; Mitchell, Gary F; Smith, Nicholas L; Holm, Hilma; Stefansson, Kari; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Samani, Nilesh J; Preuss, Michael; Rudan, Igor; Hayward, Caroline; Deary, Ian J; Wichmann, H-Erich; Raitakari, Olli T; Palmas, Walter; Kooner, Jaspal S; Stolk, Ronald P; Jukema, J Wouter; Wright, Alan F; Boomsma, Dorret I; Bandinelli, Stefania; Gyllensten, Ulf B; Wilson, James F; Ferrucci, Luigi; Schmidt, Reinhold; Farrall, Martin; Spector, Tim D; Palmer, Lyle J; Tuomilehto, Jaakko; Pfeufer, Arne; Gasparini, Paolo; Siscovick, David; Altshuler, David; Loos, Ruth JF; Toniolo, Daniela; Snieder, Harold; Gieger, Christian; Meneton, Pierre; Wareham, Nicholas J; Oostra, Ben A; Metspalu, Andres; Launer, Lenore; Rettig, Rainer; Strachan, David P; Beckmann, Jacques S; Witteman, Jacqueline CM; Erdmann, Jeanette; van Dijk, Ko Willems; Boerwinkle, Eric; Boehnke, Michael; Ridker, Paul M; Jarvelin, Marjo-Riitta; Chakravarti, Aravinda; Abecasis, Goncalo R; Gudnason, Vilmundur; Newton-Cheh, Christopher; Levy, Daniel; Munroe, Patricia B; Psaty, Bruce M; Caulfield, Mark J; Rao, Dabeeru C

    2012-01-01

    Numerous genetic loci influence systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans 1-3. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N=74,064) and follow-up studies (N=48,607), we identified at genome-wide significance (P= 2.7×10-8 to P=2.3×10-13) four novel PP loci (at 4q12 near CHIC2/PDGFRAI, 7q22.3 near PIK3CG, 8q24.12 in NOV, 11q24.3 near ADAMTS-8), two novel MAP loci (3p21.31 in MAP4, 10q25.3 near ADRB1) and one locus associated with both traits (2q24.3 near FIGN) which has recently been associated with SBP in east Asians. For three of the novel PP signals, the estimated effect for SBP was opposite to that for DBP, in contrast to the majority of common SBP- and DBP-associated variants which show concordant effects on both traits. These findings indicate novel genetic mechanisms underlying blood pressure variation, including pathways that may differentially influence SBP and DBP. PMID:21909110

  10. Effect of Fuel Injection and Mixing Characteristics on Pulse-Combustor Performance at High-Pressure

    Science.gov (United States)

    Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

    2014-01-01

    Recent calculations of pulse-combustors operating at high-pressure conditions produced pressure gains significantly lower than those observed experimentally and computationally at atmospheric conditions. The factors limiting the pressure-gain at high-pressure conditions are identified, and the effects of fuel injection and air mixing characteristics on performance are investigated. New pulse-combustor configurations were developed, and the results show that by suitable changes to the combustor geometry, fuel injection scheme and valve dynamics the performance of the pulse-combustor operating at high-pressure conditions can be increased to levels comparable to those observed at atmospheric conditions. In addition, the new configurations can significantly reduce the levels of NOx emissions. One particular configuration resulted in extremely low levels of NO, producing an emission index much less than one, although at a lower pressure-gain. Calculations at representative cruise conditions demonstrated that pulse-combustors can achieve a high level of performance at such conditions.

  11. A search for upstream pressure pulses associated with flux transfer events: An AMPTE/ISEE case study

    Science.gov (United States)

    Elphic, R. C.; Baumjohann, W.; Cattell, C. A.; Luehr, H.; Smith, M. F.

    1994-01-01

    On September 19, 1984, the Active Magnetospheric Particle Tracers Explorers (AMPTE) United Kingdom Satellite (UKS) and Ion Release Module (IRM) and International Sun Earth Explorers (ISEE) 1 and 2 spacecraft passed outbound through the dayside magnetopause at about the same time. The AMPTE spacecraft pair crossed first and were in the near-subsolar magnetosheath for more than an hour. Meanwhile the ISEE pair, about 5 R(sub E) to the south, observed flux transfer event (FTE) signatures. We use the AMPTE UKS and IRM plasma and field observations of magnetosheath conditions directly upstream of the subsolar magnetopause to check whether pressure pulses are responsible for the FTE signatures seen at ISEE. Pulses in both the ion thermal pressure and the dynamic pressure are observed in the magnetosheath early on when IRM and UKS are close to the magnetopause, but not later. These large pulses appear to be related to reconnection going on at the magnetopause nearby. AMPTE magnetosheath data far from the magnetopause do not show a pressure pulse correlation with FTEs at ISEE. Moreover, the magnetic pressure and tension effects seen in the ISEE FTEs are much larger than any pressure effects seen in the magnetosheath. A superposed epoch analysis based on small-amplitude peaks in the AMPTE magnetosheath total static pressure (nkT + B(exp 2)/2 mu(sub 0)) hint at some boundary effects, less than 5 nT peak-to-peak variations in the ISEE 1 and 2 B(sub N) signature starting about 1 min after the pressure peak epoch. However, these variations are much smaller than the standard deviations of the B(sub N) field component. Thus the evidence from this case study suggests that upstream magnetosheath pressure pulses do not give rise to FTEs, but may produce very small amplitude signatures in the magnetic field at the magnetopause.

  12. The physics of pulsed streamer discharge in high pressure air and applications to engine techonologies

    Science.gov (United States)

    Lin, Yung-Hsu

    The goal of this dissertation is to study high pressure streamers in air and apply it to diesel engine technologies. Nanosecond scale pulsed high voltage discharges in air/fuel mixtures can generate radicals which in turn have been shown to improve combustion efficiency in gasoline fueled internal combustion engines. We are exploring the possibility to extend such transient plasma generation and expected radical species generation to the range of pressures encountered in compression-ignition (diesel) engines having compression ratios of ˜20:1, thereby improving lean burning efficiency and extending the range of lean combustion. At the beginning of this dissertation, research into streamer discharges is reviewed. Then, we conducted experiments of streamer propagation at high pressures, calculated the streamer velocity based on both optical and electrical measurements, and the similarity law was checked by analyzing the streamer velocity as a function of the reduced electric field, E/P. Our results showed that the similarity law is invalid, and an empirical scaling factor, E/√P, is obtained and verified by dimensional analysis. The equation derived from the dimensional analysis will be beneficial to proper electrode and pulse generator design for transient plasma assisted internal engine experiments. Along with the high pressure study, we applied such technique on diesel engine to improve the fuel efficiency and exhaust treatment. We observed a small effect of transient plasma on peak pressure, which implied that transient plasma has the capability to improve the fuel consumption. In addition, the NO can be reduced effectively by the same technique and the energy cost is 30 eV per NO molecule.

  13. Models of brachial to finger pulse wave distortion and pressure decrement

    NARCIS (Netherlands)

    Gizdulich, P.; Prentza, A.; Wesseling, K.H.

    1997-01-01

    Objective: To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Methods: Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by

  14. Parametric Study of Pulse-Combustor-Driven Ejectors at High-Pressure

    Science.gov (United States)

    Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

    2015-01-01

    Pulse-combustor configurations developed in recent studies have demonstrated performance levels at high-pressure operating conditions comparable to those observed at atmospheric conditions. However, problems related to the way fuel was being distributed within the pulse combustor were still limiting performance. In the first part of this study, new configurations are investigated computationally aimed at improving the fuel distribution and performance of the pulse-combustor. Subsequent sections investigate the performance of various pulse-combustor driven ejector configurations operating at highpressure conditions, focusing on the effects of fuel equivalence ratio and ejector throat area. The goal is to design pulse-combustor-ejector configurations that maximize pressure gain while achieving a thermal environment acceptable to a turbine, and at the same time maintain acceptable levels of NOx emissions and flow non-uniformities. The computations presented here have demonstrated pressure gains of up to 2.8%.

  15. Effects of Acupuncture Stimulation on the Radial artery’s Pressure Pulse Wave in Healthy Young Participants: Protocol for a prospective, single-Arm, Exploratory, Clinical Study

    Directory of Open Access Journals (Sweden)

    Jae-Young Shin

    2016-09-01

    Full Text Available Introduction: This study aims to investigate the effects of acupuncture stimulation on the radial artery’s pressure pulse wave, along with various hemodynamic parameters, and to explore the possible underlying mechanism of pulse diagnosis in healthy participants in their twenties. Methods and analysis: This study is a prospective, si

  16. Time-resolved investigation of an asymmetric bipolar pulsed magnetron deposition discharge: Influence of pressure

    NARCIS (Netherlands)

    Dunger, Th.; Welzel, Th.; Welzel, S.; Richter, F.

    2005-01-01

    A bipolar pulsed magnetron deposition discharge has been studied with pulse frequencies of 100 and 150 kHz, respectively. The discharge was operated in an argon/oxygen mixture at different total pressures with a circular magnesium target as cathode. Time-resolved Langmuir double probe measurements

  17. PIEZOELECTRIC WAVEGUIDE SENSOR FOR MEASURING PULSE PRESSURE IN CLOSED LIQUID VOLUMES AT HIGH VOLTAGE ELECTRIC DISCHARGE

    Directory of Open Access Journals (Sweden)

    V. G. Zhekul

    2017-10-01

    Full Text Available Purpose. Investigations of the characteristics of pressure waves presuppose the registration of the total profile of the pressure wave at a given point in space. For these purposes, various types of «pressure to the electrical signal» transmitters (sensors are used. Most of the common sensors are unsuitable for measuring the pulse pressure in a closed water volume at high hydrostatic pressures, in particular to study the effect of a powerful high-voltage pulse discharge on increasing the inflow of minerals and drinking water in wells. The purpose of the work was to develop antijamming piezoelectric waveguide sensor for measuring pulse pressure at a close distance from a high-voltage discharge channel in a closed volume of a liquid. Methodology. We have applied the calibration method as used as a secondary standard, the theory of electrical circuits. Results. We have selected the design and the circuit solution of the waveguide pressure sensor. We have developed a waveguide pulse-pressure sensor DTX-1 with a measuring loop. This sensor makes it possible to study the spectral characteristics of pressure waves of high-voltage pulse discharge in closed volumes of liquid at a hydrostatic pressure of up to 20 MPa and a temperature of up to 80 °C. The sensor can be used to study pressure waves with a maximum amplitude value of up to 150 MPa and duration of up to 80 µs. According to the results of the calibration, the sensitivity of the developed sensor DTX-1 with a measuring loop is 0.0346 V/MPa. Originality. We have further developed the theory of designing the waveguide piezoelectric pulse pressure sensors for measuring the pulse pressure at a close distance from a high-voltage discharge channel in a closed fluid volume by controlling the attenuation of the amplitude of the pressure signal. Practical value. We have developed, created, calibrated, used in scientific research waveguide pressure pulse sensors DTX-1. We propose sensors DTX-1 for sale

  18. Ankle Blood Pressure and Pulse Pressure as Predictors of Cerebrovascular Morbidity and Mortality in a Prospective Follow-Up Study

    Directory of Open Access Journals (Sweden)

    Heikki J. Hietanen

    2010-01-01

    Full Text Available Background and Objective. We examined the association of elevated ankle blood pressure (ABP, together with exercise blood pressure, with incident cerebrovascular (CV morbidity and mortality in a prospective follow-up study of 3,808 patients. The results were compared with pulse pressure, another indicator of arterial stiffness. Methods. Patients with normal ankle and exercise brachial blood pressures were taken as the reference group. Pulse pressure was considered as quartiles with the lowest quartile as the reference category. Results. A total of 170 subjects had a CV event during the follow-up. Multivariate adjusted hazard ratio of a CV event was 2.24 (95% CI 1.43–3.52, <.0001 in patients with abnormal ABP. The pulse pressure was significant only in the model adjusted for age and sex. Conclusion. The risk of a future CV event was elevated already in those patients among whom elevated ABP was the only abnormal finding. As a risk marker, ABP is superior to the pulse pressure.

  19. Design of a high-pressure single pulse shock tube for chemical kinetic investigations

    International Nuclear Information System (INIS)

    Tranter, R. S.; Brezinsky, K.; Fulle, D.

    2001-01-01

    A single pulse shock tube has been designed and constructed in order to achieve extremely high pressures and temperatures to facilitate gas-phase chemical kinetic experiments. Postshock pressures of greater than 1000 atmospheres have been obtained. Temperatures greater than 1400 K have been achieved and, in principle, temperatures greater than 2000 K are easily attainable. These high temperatures and pressures permit the investigation of hydrocarbon species pyrolysis and oxidation reactions. Since these reactions occur on the time scale of 0.5--2 ms the shock tube has been constructed with an adjustable length driven section that permits variation of reaction viewing times. For any given reaction viewing time, samples can be withdrawn through a specially constructed automated sampling apparatus for subsequent species analysis with gas chromatography and mass spectrometry. The details of the design and construction that have permitted the successful generation of very high-pressure shocks in this unique apparatus are described. Additional information is provided concerning the diaphragms used in the high-pressure shock tube

  20. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 µm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of ...

  1. Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors

    International Nuclear Information System (INIS)

    Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk

    2010-01-01

    A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations

  2. Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors.

    Science.gov (United States)

    Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk

    2010-02-01

    A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations.

  3. Elevated pulse pressure is associated with hemolysis, proteinuria and chronic kidney disease in sickle cell disease.

    Directory of Open Access Journals (Sweden)

    Enrico M Novelli

    Full Text Available A seeming paradox of sickle cell disease is that patients do not suffer from a high prevalence of systemic hypertension in spite of endothelial dysfunction, chronic inflammation and vasculopathy. However, some patients do develop systolic hypertension and increased pulse pressure, an increasingly recognized major cardiovascular risk factor in other populations. Hence, we hypothesized that pulse pressure, unlike other blood pressure parameters, is independently associated with markers of hemolytic anemia and cardiovascular risk in sickle cell disease. We analyzed the correlates of pulse pressure in patients (n  =  661 enrolled in a multicenter international sickle cell trial. Markers of hemolysis were analyzed as independent variables and as a previously validated hemolytic index that includes multiple variables. We found that pulse pressure, not systolic, diastolic or mean arterial pressure, independently correlated with high reticulocyte count (beta  =  2.37, p  =  0.02 and high hemolytic index (beta  =  1.53, p = 0.002 in patients with homozygous sickle cell disease in two multiple linear regression models which include the markers of hemolysis as independent variables or the hemolytic index, respectively. Pulse pressure was also independently associated with elevated serum creatinine (beta  =  3.21, p  =  0.02, and with proteinuria (beta  =  2.52, p  =  0.04. These results from the largest sickle cell disease cohort to date since the Cooperative Study of Sickle Cell Disease show that pulse pressure is independently associated with hemolysis, proteinuria and chronic kidney disease. We propose that high pulse pressure may be a risk factor for clinical complications of vascular dysfunction in sickle cell disease. Longitudinal and mechanistic studies should be conducted to confirm these hypotheses.

  4. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J.P. (GRECO ILM, Laboratoire d' Energetique et Detonique, E.N.S.M.A., 86 - Poitiers (France))

    1984-11-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 ..mu..m wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined.

  5. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 μm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined

  6. Bruce and Darlington power pulse and pressure tube integrity programs -status 1995

    Energy Technology Data Exchange (ETDEWEB)

    Field, G J [Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Wylie, J [Ontario Hydro, Tiverton, ON (Canada). Bruce Nuclear Generating Station-A

    1996-12-31

    The optimum solution to pressure tube fretting at the inlet of the Bruce and Darlington channels, a concern which became very serious following inspections in early 1992, is to remove the inlet bundle and operate with a 12 fuel bundle channel. During analysis of this operating mode a `power pulse` was identified which could occur during an inlet header break where all the fuel in the channel moved rapidly to the inlet of the channel. The pulse was unacceptable and the units were derated until solutions could be implemented. A number of solutions were identified and each station has begun implementation of their specific solution. Implementation has not been without problems and this paper provides a status report on the progress to date of the long bundle implementation solution for Bruce B and Darlington and the fuelling with the flow solution being implemented at Bruce A. Both types of solution have a significant impact on the original concern, fretting of the pressure tube. (author). 1 ref., 6 figs.

  7. Pressure tunable cascaded third order nonlinearity and temporal pulse switching

    DEFF Research Database (Denmark)

    Eilenberger, Falk; Bache, Morten; Minardi, Stefano

    2013-01-01

    Effects based on the χ(3)-nonlinearity are arguably the most commonly discussed nonlinear interactions in photonics. In the description of pulse propagation, however, the generation of the third harmonic (TH) is commonly neglected, because it is strongly phase mismatched in most materials...

  8. Increased pulse pressure is associated with left atrial enlargement in resistant hypertensive patients.

    Science.gov (United States)

    Armario, Pedro; Oliveras, Anna; Hernández-Del-Rey, Raquel; Suárez, Carmen; Martell, Nieves; Ruilope, Luis M; De La Sierra, Alejandro

    2013-02-01

    Resistant hypertension (RH) is frequently associated with a high prevalence of target organ damage, which impairs the prognosis of these patients. Considering cardiac alterations in RH, most attention has been devoted to left ventricular hypertrophy (LVH), but data concerning left atrial enlargement (LAE) is less known. This cross-sectional study assessed the factors associated with LAE, with special focus on blood pressure (BP) estimates obtained by ambulatory blood pressure monitoring (ABPM), in 250 patients with RH, aged 64 ± 11 years. LAE and LVH were observed in 10.0% (95% CI 6.3-13.7) and 57.1% (95% CI 50.8-63.5) of patients, respectively. Compared with patients with normal atrium size, those exhibiting LAE were older, more frequently women, had elevated pulse pressure (PP) measured both at the office and by ABPM, and showed higher prevalence of LVH (83% vs 54%; p = 0.016). In a logistic regression analysis, adjusting for age, gender, body mass index, left ventricular mass index and BP pressure estimates, night-time PP was independently associated with LAE (OR for 5 mmHg = 1.28, 95% CI 1.24-1.32; p = 0.001). In conclusion, besides classical determinants of LAE, such as age and LVH, an elevated night-time PP was independently associated with LAE in patients with RH.

  9. Models of WO x films growth during pulsed laser deposition at elevated pressures of reactive gas

    Science.gov (United States)

    Gnedovets, A. G.; Fominski, V. Y.; Nevolin, V. N.; Romanov, R. I.; Fominski, D. V.; Soloviev, A. A.

    2017-12-01

    The films of tungsten oxides were prepared by pulsed laser ablation of W target in a reactive gas atmosphere (air of laboratory humidity). Optical analysis and ion signal measurements for the laser plume allowed to recognise a threshold gas pressure that suppresses the deposition of non-scattered atomic flux from the plume. When the pressure exceeds about 40 Pa, the films grow due to the deposition of species that could be formed in collisions of W atoms with reactive molecules (e.g., O2). Kinetic Monte Carlo method was used for modelling film growth. Comparison of the model structures with the experimentally prepared films has shown that the growth mechanism of ballistic deposition at a pressure of 40 Pa could be changed on the diffusion limited aggregation at a pressure of ~100 Pa. Thus, a cauliflower structure of the film transformed to a web-like structure. For good correlation of experimental and model structures of WO x , a dimension of structural elements in the model should coincide with W-O cluster size.

  10. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    International Nuclear Information System (INIS)

    Huo, W. G.; Jian, S. J.; Yao, J.; Ding, Z. F.

    2014-01-01

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times

  11. Stress analysis of pressure vessels

    International Nuclear Information System (INIS)

    Kim, B.K.; Song, D.H.; Son, K.H.; Kim, K.S.; Park, K.B.; Song, H.K.; So, J.Y.

    1979-01-01

    This interim report contains the results of the effort to establish the stress report preparation capability under the research project ''Stress analysis of pressure vessels.'' 1978 was the first year in this effort to lay the foundation through the acquisition of SAP V structural analysis code and a graphic terminal system for improved efficiency of using such code. Software programming work was developed in pre- and post processing, such as graphic presentation of input FEM mesh geometry and output deformation or mode shope patterns, which was proven to be useful when using the FEM computer code. Also, a scheme to apply fracture mechanics concept was developed in fatigue analysis of pressure vessels. (author)

  12. LOFT differential pressure uncertainty analysis

    International Nuclear Information System (INIS)

    Evans, R.P.; Biladeau, G.L.; Quinn, P.A.

    1977-03-01

    A performance analysis of the LOFT differential pressure (ΔP) measurement is presented. Along with completed descriptions of test programs and theoretical studies that have been conducted on the ΔP, specific sources of measurement uncertainty are identified, quantified, and combined to provide an assessment of the ability of this measurement to satisfy the SDD 1.4.1C (June 1975) requirement of measurement of differential pressure

  13. Ejector-Enhanced, Pulsed, Pressure-Gain Combustor

    Science.gov (United States)

    Paxson, Daniel E.; Dougherty, Kevin T.

    2009-01-01

    An experimental combination of an off-the-shelf valved pulsejet combustor and an aerodynamically optimized ejector has shown promise as a prototype of improved combustors for gas turbine engines. Despite their name, the constant pressure combustors heretofore used in gas turbine engines exhibit typical pressure losses ranging from 4 to 8 percent of the total pressures delivered by upstream compressors. In contrast, the present ejector-enhanced pulsejet combustor exhibits a pressure rise of about 3.5 percent at overall enthalpy and temperature ratios compatible with those of modern turbomachines. The modest pressure rise translates to a comparable increase in overall engine efficiency and, consequently, a comparable decrease in specific fuel consumption. The ejector-enhanced pulsejet combustor may also offer potential for reducing the emission of harmful exhaust compounds by making it practical to employ a low-loss rich-burn/quench/lean-burn sequence. Like all prior concepts for pressure-gain combustion, the present concept involves an approximation of constant-volume combustion, which is inherently unsteady (in this case, more specifically, cyclic). The consequent unsteadiness in combustor exit flow is generally regarded as detrimental to the performance of downstream turbomachinery. Among other adverse effects, this unsteadiness tends to detract from the thermodynamic benefits of pressure gain. Therefore, it is desirable in any intermittent combustion process to minimize unsteadiness in the exhaust path.

  14. Prediction of electromagnetic pulse generation by picosecond avalanches in high-pressure air

    International Nuclear Information System (INIS)

    Mayhall, D.J.; Yee, J.H.

    1993-01-01

    The gas avalanche switch is a laser-activated, high-voltage switch, consisting of a set of pulse-charged electrodes in a high-pressure gas. Induced electrons from a picosecond-scale laser pulse initiate an avalanche discharge between high-voltage and grounded electrodes. If the voltage, pressure, and dimensions are correct, the rapid avalanche, fueled by the immense number of electrons available in the gas, collapses the applied voltage in picoseconds and generates electromagnetic pulses with widths as short as 1-10 ps and 3 dB bandwidths of 20-120 GHz. With proper voltage or pressure detuning, wider pulses and lower bandwidths occur. In addition to picosecond electromagnetic pulse generation, application of this switch should result in ultra-fast Marx bank pulsers. A number of versions of the switch are possible. The simplest is a parallel plate capacitor, consisting of a gas between two parallel plate conductors. High voltage is applied across the two plates. A parallel plate, Blumlein geometry features a center electrode between two grounded parallel plates. This geometry emits a single pulse in each direction along the parallel plates. A frozen wave geometry with multiple, oppositely charged center electrodes will emit AC pulses. Series switches consisting of gas gaps between two electrodes are also possible

  15. Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Lotte [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Buczynska, Anna [Departement of Chemistry, UA, Wilrijk (Belgium); Walgraeve, Christophe [Research group EnVOC, Department of Sustainable Organic Chemistry and Technology, UGent, Gent (Belgium); Delcloo, Andy [Royal Meteorological Institute, Brussels (Belgium); Potgieter-Vermaak, Sanja [Departement of Chemistry, UA, Wilrijk (Belgium); Molecular Science Institute, School of Chemistry, University of Witwatersrand, Johannesburg (South Africa); Division of Chemistry and Environmental Science, Manchester Metropolitan University, Manchester (United Kingdom); Van Grieken, Rene [Departement of Chemistry, UA, Wilrijk (Belgium); Demeestere, Kristof; Dewulf, Jo; Van Langenhove, Herman [Research group EnVOC, Department of Sustainable Organic Chemistry and Technology, UGent, Gent (Belgium); De Backer, Hugo [Royal Meteorological Institute, Brussels (Belgium); Nemery, Benoit, E-mail: ben.nemery@med.kuleuven.be [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Nawrot, Tim S. [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Centre for Environmental Sciences, Hasselt University, Diepenbeek (Belgium)

    2012-08-15

    An increased pulse pressure (difference between systolic and diastolic blood pressure) suggests aortic stiffening. The objective of this study was to examine the acute effects of both particulate matter (PM) mass and composition on blood pressure, among elderly persons. We carried out a panel study in persons living in elderly homes in Antwerp, Belgium. We recruited 88 non-smoking persons, 70% women with a mean age of 83 years (standard deviation: 5.2). Blood pressure was measured and a blood sample was collected on two time points, which were chosen so that there was an exposure contrast in ambient PM exposure. The elemental content of the collected indoor and outdoor PM{sub 2.5} (particulate matter with an aerodynamic diameter <2.5 {mu}m) mass concentration was measured. Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on outdoor PM{sub 10} (particulate matter with an aerodynamic diameter <10 {mu}m) were measured. Each interquartile range increase of 20.8 {mu}g/m Superscript-Three in 24-h mean outdoor PM{sub 2.5} was associated with an increase in pulse pressure of 4.0 mmHg (95% confidence interval: 1.8-6.2), in persons taking antihypertensive medication (n=57), but not in persons not using antihypertensive medication (n=31) (p for interaction: 0.02). Vanadium, iron and nickel contents of PM{sub 2.5} were significantly associated with systolic blood pressure and pulse pressure, among persons on antihypertensive medication. Similar results were found for indoor concentrations. Of the oxy-PAHs, chrysene-5,6-dione and benzo[a]pyrene-3,6-dione were significantly associated with increases in systolic blood pressure and pulse pressure. In elderly, pulse pressure was positively associated with acute increases in outdoor and indoor air pollution, among persons taking antihypertensive medication. These results might form a mechanistic pathway linking air pollution as a trigger of cardiovascular events.

  16. Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

    Science.gov (United States)

    Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

    2017-05-01

    Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Tree shoot bending generates hydraulic pressure pulses: a new long-distance signal?

    Science.gov (United States)

    Lopez, Rosana; Badel, Eric; Peraudeau, Sebastien; Leblanc-Fournier, Nathalie; Beaujard, François; Julien, Jean-Louis; Cochard, Hervé; Moulia, Bruno

    2014-05-01

    When tree stems are mechanically stimulated, a rapid long-distance signal is induced that slows down primary growth. An investigation was carried out to determine whether the signal might be borne by a mechanically induced pressure pulse in the xylem. Coupling xylem flow meters and pressure sensors with a mechanical testing device, the hydraulic effects of mechanical deformation of tree stem and branches were measured. Organs of several tree species were studied, including gymnosperms and angiosperms with different wood densities and anatomies. Bending had a negligible effect on xylem conductivity, even when deformations were sustained or were larger than would be encountered in nature. It was found that bending caused transient variation in the hydraulic pressure within the xylem of branch segments. This local transient increase in pressure in the xylem was rapidly propagated along the vascular system in planta to the upper and lower regions of the stem. It was shown that this hydraulic pulse originates from the apoplast. Water that was mobilized in the hydraulic pulses came from the saturated porous material of the conduits and their walls, suggesting that the poroelastic behaviour of xylem might be a key factor. Although likely to be a generic mechanical response, quantitative differences in the hydraulic pulse were found in different species, possibly related to differences in xylem anatomy. Importantly the hydraulic pulse was proportional to the strained volume, similar to known thigmomorphogenetic responses. It is hypothesized that the hydraulic pulse may be the signal that rapidly transmits mechanobiological information to leaves, roots, and apices.

  18. Investigation of HEPA filters subjected to tornado pressure pulses

    International Nuclear Information System (INIS)

    Gregory, W.S.; Horak, H.L.; Smith, P.R.; Ricketts, C.

    1977-03-01

    An experimental program is described that will determine the response of 0.6-x 0.6-m (24-x 24-in.) high-efficiency particulate air (HEPA) filters to tornado-induced pressure transients. A blow-down system will be used to impose pressure differentials across the filters. Progress in construction of this system is reported with a description of the component parts and their functions. The test facility is essentially complete with the exception of an air dryer system that has not yet been delivered. Initial structural testing will begin in March 1977. A description is given of the instrumentation needed to measure air pressure, velocity, turbulence, humidity and particulate concentration. This instrumentation includes pressure transducers, humidity equipment, laser Doppler velocimeters (LDV), signal processors and a data acquisition system. Operational theory of the LDV and its proposed use as a particle counting device are described

  19. Effect of interval training programme on pulse pressure in the ...

    African Journals Online (AJOL)

    EB

    2013-09-03

    Systolic Blood Pressure ... are consistent with the pathophysiological processes ... Hospitals Management Board and the faculty of ... et al13 using an automated digital electronic BP ..... however, warrants attention in future studies.

  20. Pulse pressure and nocturnal fall in blood pressure are predictors of vascular, cardiac and renal target organ damage in hypertensive patients (LOD-RISK study).

    Science.gov (United States)

    García-Ortiz, Luis; Gómez-Marcos, Manuel A; Martín-Moreiras, Javier; González-Elena, Luis J; Recio-Rodriguez, Jose I; Castaño-Sánchez, Yolanda; Grandes, Gonzalo; Martínez-Salgado, Carlos

    2009-08-01

    To analyse the relationship between various parameters derived from ambulatory blood pressure monitoring (ABPM) and vascular, cardiac and renal target organ damage. A cross-sectional, descriptive study. It included 353 patients with short-term or recently diagnosed hypertension. ABPM, carotid intima-media thickness (IMT), Cornell voltage-duration product (Cornell VDP), glomerular filtration rate and albumin/creatinine ratio to assess vascular, cardiac and renal damage. Two hundred and twenty-three patients (63.2%) were males, aged 56.12+/-11.21 years. The nocturnal fall in blood pressure was 11.33+/-8.41, with a dipper pattern in 49.0% (173), nondipper in 30.3% (107), extreme dipper in 12.7% (45) and riser in 7.9% (28). The IMT was lower in the extreme dipper (0.716+/-0.096 mm) and better in the riser pattern (0.794+/-0.122 mm) (P<0.05). The Cornell VDP and albumin/creatinine ratio were higher in the riser pattern (1818.94+/-1798.63 mm/ms and 140.78+/-366.38 mg/g, respectively) than in the other patterns. In the multivariate analysis after adjusting for age, sex and antihypertensive treatment, with IMT as dependent variable the 24-h pulse pressure (beta = 0.003), with Cornell VDP the rest pulse pressure (beta = 12.04), and with the albumin/creatinine ratio the percentage of nocturnal fall in systolic blood pressure (beta = -3.59), the rest heart rate (beta = 1.83) and the standard deviation of 24-h systolic blood pressure (beta = 5.30) remain within the equation. The estimated pulse pressure with ABPM is a predictor of vascular and cardiac organ damage. The nocturnal fall and the standard deviation in 24-h systolic blood pressure measured with the ABPM is a predictor of renal damage.

  1. Perceived social isolation moderates the relationship between early childhood trauma and pulse pressure in older adults.

    Science.gov (United States)

    Norman, Greg J; Hawkley, Louise; Ball, Aaron; Berntson, Gary G; Cacioppo, John T

    2013-06-01

    Over a million children are subjected to some form of trauma in the United States every year. Early trauma has been shown to have deleterious effects on cardiovascular health in adulthood. However, the presence of strong social relationships as an adult can buffer an individual against many of the harmful effects of early trauma. Furthermore, the perception of social isolation has been shown to be a significant risk factor for the development of cardiovascular disease and is a strong predictor of all cause mortality. One likely mechanism thought to underlie the influence of perceived isolation on health is changes in arterial stiffness. One of the more widely used measures of arterial stiffness in older individuals is pulse pressure. The goal of the present study was to determine whether early childhood trauma is associated with elevations on pulse pressure. Furthermore, this study sought to determine whether perceived social isolation moderates the relationship between early trauma and pulse pressure. Results revealed that individuals with low perceived social isolation displayed no significant relationship between early trauma and pulse pressure. However, individuals who reported higher levels of perceived isolation showed a significant positive association between early trauma and pulse pressure. Therefore, the detrimental effects of early trauma may be partially dependent upon the quality of social relationships as an adult. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

    Science.gov (United States)

    Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

    2016-01-01

    The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

  3. Future pulsed magnetic field applications in dynamic high pressure research

    International Nuclear Information System (INIS)

    Fowler, C.M.; Caird, R.S.; Hawke, R.S.; Burgess, T.J.

    1977-01-01

    The generation of large pressures by magnetic fields to obtain equation of state information is of fairly recent origin. Magnetic fields used in compression experiments produce an almost isentropic sample compression. Axial magnetic field compression is discussed together with a few results chosen to show both advantages and limitations of the method. Magnetic compression with azimuthal fields is then considered. Although there are several potential pitfalls, the possibilities are encouraging for obtaining very large pressures. Next, improved diagnostic techniques are considered. An x-ray ''streaking camera'' is proposed for volume measurements and a more detailed discussion is given on the use of the shift of the ruby fluorescence lines for pressure measurements. Finally, some additional flux compression magnetic field sources are discussed briefly. 5 figures, 2 tables

  4. Optical Properties Dependence with Gas Pressure in AlN Films Deposited by Pulsed Laser Ablation

    International Nuclear Information System (INIS)

    Perez, J A; Riascos, H; Caicedo, J C; Cabrera, G; Yate, L

    2011-01-01

    AlN films were deposited by pulsed laser deposition technique (PLD) using an Nd: YAG laser (λ = 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the target was an aluminum high purity (99.99%). The films were deposited with a laser fluence of 7 J/cm2 for 10 minutes on silicon (100) substrates. The substrate temperature was 300 deg. C and the working pressure was varied from 3 mtorr to 11 mtorr. The thickness measured by profilometer was 150 nm for all films. The crystallinity was observed via XRD pattern, the morphology and composition of the films were studied using scanning electron microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), respectively. The optical reflectance spectra and color coordinates of the films were obtained by optical spectral reflectometry technique in the range of 400 cm-1- 900 cm-1 by an Ocean Optics 2000 spectrophotometer. In this work, a clear dependence of the reflectance, dominant wavelength and color purity was found in terms of the applied pressure to the AlN films. A reduction in reflectance of about 55% when the pressure was increased from 3 mtorr to 11 mtorr was observed. This paper deals with the formation of AlN thin films as promising materials for the integration of SAW devices on Si substrates due to their good piezoelectric properties and the possibility of deposition at low temperature compatible with the manufacturing of Si integrated circuits.

  5. Optical Properties Dependence with Gas Pressure in AlN Films Deposited by Pulsed Laser Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J A; Riascos, H [Departamento de Fisica, Universidad Tecnologica de Pereira, Grupo plasma Laser y Aplicaciones A.A 097 (Colombia); Caicedo, J C [Grupo pelIculas delgadas, Universidad del Valle, Cali (Colombia); Cabrera, G; Yate, L, E-mail: jcaicedoangulo@gmail.com [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain)

    2011-01-01

    AlN films were deposited by pulsed laser deposition technique (PLD) using an Nd: YAG laser ({lambda} = 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the target was an aluminum high purity (99.99%). The films were deposited with a laser fluence of 7 J/cm2 for 10 minutes on silicon (100) substrates. The substrate temperature was 300 deg. C and the working pressure was varied from 3 mtorr to 11 mtorr. The thickness measured by profilometer was 150 nm for all films. The crystallinity was observed via XRD pattern, the morphology and composition of the films were studied using scanning electron microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), respectively. The optical reflectance spectra and color coordinates of the films were obtained by optical spectral reflectometry technique in the range of 400 cm-1- 900 cm-1 by an Ocean Optics 2000 spectrophotometer. In this work, a clear dependence of the reflectance, dominant wavelength and color purity was found in terms of the applied pressure to the AlN films. A reduction in reflectance of about 55% when the pressure was increased from 3 mtorr to 11 mtorr was observed. This paper deals with the formation of AlN thin films as promising materials for the integration of SAW devices on Si substrates due to their good piezoelectric properties and the possibility of deposition at low temperature compatible with the manufacturing of Si integrated circuits.

  6. Some characteristics of the digitization pulses from high pressure neon-helium flash tubes

    International Nuclear Information System (INIS)

    Chan, D.S.K.; Leung, S.K.; Ng, L.K.

    1979-01-01

    Characteristics of the digitization output pulses from high pressure neon-helium flash tubes were studied under various operation conditions using square ultra-high voltage pulses. Properties reported by previous workers were compared. Two discharge mechanisms, the Townsend avalanche discharge and the streamer discharge, were observed to occur in sequence in some events. The output waveforms for both discharge mechanisms were studied in detail. The charge induced on a detecting probe was also estimated from the measured data. (Auth.)

  7. Explosive Processes on Cathode while Forming Nanosecond Pulsed Discharge of High Pressure

    Directory of Open Access Journals (Sweden)

    A. M. Hashimov

    2012-01-01

    Full Text Available The paper is devoted to research of cathode surfaces with different curvature radius (r = 1–8 mm while forming nanosecond pulsed discharge in dense air. Influence of field and air pressure heterogeneity rate in gas gap on size of micro-craters being formed on working cathode surface after pulsed effect has been shown in the paper. The paper reveals a maximum expansion of separate micro-crater size on cathode surface with small curvature radius.

  8. Electromagnetic Pulse Coupling Analysis of Electronic Equipment

    OpenAIRE

    Hong Lei; Qingying LI

    2017-01-01

    High-intensity nuclear explosion caused by high-altitude nuclear electromagnetic pulse through the antenna, metal cables, holes and other channels, coupled with very high energy into the electronic device, and cause serious threats. In this paper, the mechanism, waveform, coupling path and damage effect of nuclear electromagnetic pulse is analyzed, and the coupling mechanism of nuclear electromagnetic pulse is studied.

  9. Phylloquinone (vitamin K₁) intake and pulse pressure as a measure of arterial stiffness in older adults.

    Science.gov (United States)

    Vaccaro, Joan A; Huffman, Fatma G

    2013-01-01

    This study examined the relationships among ethnicity/race, lifestyle factors, phylloquinone (vitamin K₁) intake, and arterial pulse pressure in a nationally representative sample of older adults from four ethnic/racial groups: non-Hispanic Whites, non-Hispanic Blacks, Mexican Americans, and other Hispanics. This was a cross-sectional study of U.S. representative sample with data from the National Health and Nutrition Examination Surveys, 2007-2008 and 2009-2010 of adults aged 50 years and older (N = 5296). Vitamin K intake was determined by 24-hour recall. Pulse pressure was calculated as the difference between the averages of systolic blood pressure and diastolic blood pressure. Compared to White non-Hispanics, the other ethnic/racial groups were more likely to have inadequate vitamin K₁ intake. Inadequate vitamin K₁ intake was an independent predictor of high arterial pulse pressure. This was the first study that compared vitamin K₁ inadequacy with arterial pulse pressure across ethnicities/races in U.S. older adults. These findings suggest that vitamin K screening may be a beneficial marker for the health of older adults.

  10. Patient Blood Pressure and Pulse Rate Monitoring With an Alert ...

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... an Alert System Using the Omron 790it Blood Pressure. Monitor ... detailed medical information on the vital signs of patients and will save many lives that may be lost. Keywords: Omron .... at rest, in beats per minute (BPM):.

  11. Vascular Stiffness and Increased Pulse Pressure in the Aging Cardiovascular System

    Directory of Open Access Journals (Sweden)

    Jochen Steppan

    2011-01-01

    Full Text Available Aging leads to a multitude of changes in the cardiovascular system, including systolic hypertension, increased central vascular stiffness, and increased pulse pressure. In this paper we will review the effects of age-associated increased vascular stiffness on systolic blood pressure, pulse pressure, augmentation index, and cardiac workload. Additionally we will describe pulse wave velocity as a method to measure vascular stiffness and review the impact of increased vascular stiffness as an index of vascular health and as a predictor of adverse cardiovascular outcomes. Furthermore, we will discuss the underlying mechanisms and how these may be modified in order to change the outcomes. A thorough understanding of these concepts is of paramount importance and has therapeutic implications for the increasingly elderly population.

  12. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    CERN Document Server

    Troyer, G L

    2000-01-01

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse r...

  13. Experimental hydrocephalus following mechanical increment of intraventricular pulse pressure.

    Science.gov (United States)

    Di Rocco, C; Pettorossi, V E; Caldarelli, M; Mancinelli, R; Velardi, F

    1977-11-15

    Experimental hydrocephalus has been induced in lambs by artificial increase of the amplitude of intraventricular cerebrospinal fluid (CSF) oscillations related to arterial pulsations, without concomitant changes of the mean CSF-pressure. The characteristics of this hydrocephalus demonstrate that the intraventricular CSF-pulsations can play a role in the genesis of ventricular dilation. Such a method may be used to produce an original model of hydrocephalus independent of changes of CSF-circulation or absorption.

  14. Design of a Continuous Blood Pressure Measurement System Based on Pulse Wave and ECG Signals.

    Science.gov (United States)

    Li, Jian-Qiang; Li, Rui; Chen, Zhuang-Zhuang; Deng, Gen-Qiang; Wang, Huihui; Mavromoustakis, Constandinos X; Song, Houbing; Ming, Zhong

    2018-01-01

    With increasingly fierce competition for jobs, the pressures on people have risen in recent years, leading to lifestyle and diet disorders that result in significantly higher risks of cardiovascular disease. Hypertension is one of the common chronic cardiovascular diseases; however, mainstream blood pressure measurement devices are relatively heavy. When multiple measurements are required, the user experience and the measurement results may be unsatisfactory. In this paper, we describe the design of a signal collection module that collects pulse waves and electrocardiograph (ECG) signals. The collected signals are input into a signal processing module to filter the noise and amplify the useful physiological signals. Then, we use a wavelet transform to eliminate baseline drift noise and detect the feature points of the pulse waves and ECG signals. We propose the concept of detecting the wave shape associated with an instance, an approach that minimizes the impact of atypical pulse waves on blood pressure measurements. Finally, we propose an improved method for measuring blood pressure based on pulse wave velocity that improves the accuracy of blood pressure measurements by 58%. Moreover, the results meet the american medical instrument promotion association standards, which demonstrate the feasibility of our measurement system.

  15. Melodic algorithms for pulse oximetry to allow audible discrimination of abnormal systolic blood pressures.

    Science.gov (United States)

    Chima, Ranjit S; Ortega, Rafael; Connor, Christopher W

    2014-12-01

    An anesthesiologist must remain vigilant of the patient's clinical status, incorporating many independent physiological measurements. Oxygen saturation and heart rate are represented by continuous audible tones generated by the pulse oximeter, a mandated monitoring device. Other important clinical parameters--notably blood pressure--lack any audible representation beyond arbitrarily-configured threshold alarms. Attempts to introduce further continuous audible tones have apparently foundered; the complexity and interaction of these tones have exceeded the ability of clinicians to interpret them. Instead, we manipulate the tonal and rhythmic structure of the accepted pulse oximeter tone pattern melodically. Three melodic algorithms were developed to apply tonal and rhythmic variations to the continuous pulse oximeter tone, dependent on the systolic blood pressure. The algorithms distort the original audible pattern minimally, to facilitate comprehension of both the underlying pattern and the applied variations. A panel of anesthesia practitioners (attending anesthesiologists, residents and nurse anesthetists) assessed these algorithms in characterizing perturbations in cardiopulmonary status. Twelve scenarios, incorporating combinations of oxygen desaturation, bradycardia, tachycardia, hypotension and hypertension, were tested. A rhythmic variation in which additional auditory information was conveyed only at halftime intervals, with every other "beat" of the pulse oximeter, was strongly favored. The respondents also strongly favored the use of musical chords over single tones. Given three algorithms of tones embedded in the pulse oximeter signal, anesthesiologists preferred a melodic tone to signal a significant change in blood pressure.

  16. Direct injection of high pressure gas : scaling properties of pulsed turbulent jets

    NARCIS (Netherlands)

    Baert, R.S.G.; Klaassen, A.; Doosje, E.

    2010-01-01

    Existing gasoline DI injection equipment has been modified to generate single hole pulsed gas jets. Injection experiments have been performed at combinations of 3 different pressure ratios (2 of which supercritical) respectively 3 different hole geometries (i.e. length to diameter ratios). Injection

  17. Blood pressure and pulse rate of apparently healthy adults on land ...

    African Journals Online (AJOL)

    Blood pressure and pulse rate of apparently healthy adults on land and in water: A comparative study. AI Bello, BOA Adegoke, OA Abass, O Addo. Abstract. Objective: The study compared cardiovascular parameters of apparently healthy adults in erect standing posture on land and whilst immersed in water at rest. Methods: ...

  18. Arterial compliance in patients with cirrhosis: stroke volume-pulse pressure ratio as simplified index

    DEFF Research Database (Denmark)

    Fuglsang, S; Bendtsen, F; Christensen, E

    2001-01-01

    Arterial function may be altered in patients with cirrhosis. We determined compliance of the arterial tree (C(1)) in relation to systemic and splanchnic hemodynamic derangement and clinical variables. C(1) and the stroke volume-pulse pressure index (SV/PP) were significantly higher (+62% and +40%...... predictors of SV/PP (P abnormalities in the arterial compliance of these patients....

  19. Effect of Pulsed Ultraviolet Light and High Hydrostatic Pressure on the Antigenicity of Almond Protein Extracts.

    Science.gov (United States)

    The efficacy of pulsed ultraviolet light (PUV) and high hydrostatic pressure (HHP) on reducing the IgE binding to the almond extracts, was studied using SDS-PAGE, Western Blot, and ELISA probed with human plasma containing IgE antibodies to almond allergens, and a polyclonal antibody against almond ...

  20. REFLECTANCE PULSE OXIMETRY AT THE FOREHEAD IMPROVES BY PRESSURE ON THE PROBE

    NARCIS (Netherlands)

    DASSEL, ACM; GRAAFF, R; SIKKEMA, M; ZIJLSTRA, WG; AARNOUDSE, JG

    In this study, we investigated the possibility of improving reflectance (back-scatter) pulse oximetry measurements by pressure applied to the probe. Optimal signal detection, with the probe applied to an easily accessible location, is important to prevent erroneous oxygen saturation readouts. At the

  1. Polynomial analysis of ambulatory blood pressure measurements

    NARCIS (Netherlands)

    Zwinderman, A. H.; Cleophas, T. A.; Cleophas, T. J.; van der Wall, E. E.

    2001-01-01

    In normotensive subjects blood pressures follow a circadian rhythm. A circadian rhythm in hypertensive patients is less well established, and may be clinically important, particularly with rigorous treatments of daytime blood pressures. Polynomial analysis of ambulatory blood pressure monitoring

  2. Thermodynamic analysis of a pulse tube engine

    International Nuclear Information System (INIS)

    Moldenhauer, Stefan; Thess, André; Holtmann, Christoph; Fernández-Aballí, Carlos

    2013-01-01

    Highlights: ► Numerical model of the pulse tube engine process. ► Proof that the heat transfer in the pulse tube is out of phase with the gas velocity. ► Proof that a free piston operation is possible. ► Clarifying the thermodynamic working principle of the pulse tube engine. ► Studying the influence of design parameters on the engine performance. - Abstract: The pulse tube engine is an innovative simple heat engine based on the pulse tube process used in cryogenic cooling applications. The working principle involves the conversion of applied heat energy into mechanical power, thereby enabling it to be used for electrical power generation. Furthermore, this device offers an opportunity for its wide use in energy harvesting and waste heat recovery. A numerical model has been developed to study the thermodynamic cycle and thereby help to design an experimental engine. Using the object-oriented modeling language Modelica, the engine was divided into components on which the conservation equations for mass, momentum and energy were applied. These components were linked via exchanged mass and enthalpy. The resulting differential equations for the thermodynamic properties were integrated numerically. The model was validated using the measured performance of a pulse tube engine. The transient behavior of the pulse tube engine’s underlying thermodynamic properties could be evaluated and studied under different operating conditions. The model was used to explore the pulse tube engine process and investigate the influence of design parameters.

  3. Influence of aerobic exercise training on post-exercise responses of aortic pulse pressure and augmentation pressure in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Nobuhiko eAkazawa

    2015-10-01

    Full Text Available Central arterial blood pressure (BP is more predictive of future cardiovascular events than is brachial BP because it reflects the BP load imposed on the left ventricle with greater accuracy. However, little is known about the effects of exercise training on central hemodynamic response to acute exercise. The purpose of the present study was to determine the influence of an aerobic exercise regimen on the response of aortic BP after a single aerobic exercise in postmenopausal women. Nine healthy postmenopausal women (age: 61 ± 2 years participated in a 12-week aerobic exercise training regimen. Before and after the training, each subjects performed a single bout of cycling at ventilatory thresholds for 30 min. We evaluated the post-exercise aortic BP response, which was estimated via the general transfer function from applanation tonometry. After the initial pre-training aerobic exercise session, aortic BP did not change significantly: however, aortic pulse pressure and augmentation pressure were significantly attenuated after the single aerobic exercise session following the 12-week training regimen. The present study demonstrated that a regular aerobic exercise training regimen induced the post-exercise reduction of aortic pulse pressure and augmentation pressure. Regular aerobic exercise training may enhance post-exercise reduction in aortic BP.

  4. Analysis of picosecond pulsed laser melted graphite

    International Nuclear Information System (INIS)

    Steinbeck, J.; Braunstein, G.; Speck, J.; Dresselhaus, M.S.; Huang, C.Y.; Malvezzi, A.M.; Bloembergen, N.

    1986-01-01

    A Raman microprobe and high resolution TEM have been used to analyze the resolidified region of liquid carbon generated by picosecond pulse laser radiation. From the relative intensities of the zone center Raman-allowed mode for graphite at 1582 cm -1 and the disorder-induced mode at 1360 cm -1 , the average graphite crystallite size in the resolidified region is determined as a function of position. By comparison with Rutherford backscattering spectra and Raman spectra from nonosecond pulsed laser melting experiments, the disorder depth for picosecond pulsed laser melted graphite is determined as a function of irradiating energy density. Comparisons of TEM micrographs for nanosecond and picosecond pulsed laser melting experiments show that the structure of the laser disordered regions in graphite are similar and exhibit similar behavior with increasing laser pulse fluence

  5. Pressure relieving support surfaces (PRESSURE) trial: cost effectiveness analysis.

    Science.gov (United States)

    Iglesias, Cynthia; Nixon, Jane; Cranny, Gillian; Nelson, E Andrea; Hawkins, Kim; Phillips, Angela; Torgerson, David; Mason, Su; Cullum, Nicky

    2006-06-17

    To assess the cost effectiveness of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers in patients admitted to hospital. Cost effectiveness analysis carried out alongside the pressure relieving support surfaces (PRESSURE) trial; a multicentre UK based pragmatic randomised controlled trial. 11 hospitals in six UK NHS trusts. Intention to treat population comprising 1971 participants. Kaplan Meier estimates of restricted mean time to development of pressure ulcers and total costs for treatment in hospital. Alternating pressure mattresses were associated with lower overall costs (283.6 pounds sterling per patient on average, 95% confidence interval--377.59 pounds sterling to 976.79 pounds sterling) mainly due to reduced length of stay in hospital, and greater benefits (a delay in time to ulceration of 10.64 days on average,--24.40 to 3.09). The differences in health benefits and total costs for hospital stay between alternating pressure mattresses and alternating pressure overlays were not statistically significant; however, a cost effectiveness acceptability curve indicated that on average alternating pressure mattresses compared with alternating pressure overlays were associated with an 80% probability of being cost saving. Alternating pressure mattresses for the prevention of pressure ulcers are more likely to be cost effective and are more acceptable to patients than alternating pressure overlays.

  6. Acetylcysteine reduces plasma homocysteine concentration and improves pulse pressure and endothelial function in patients with end-stage renal failure

    DEFF Research Database (Denmark)

    Scholze, Alexandra; Rinder, Christiane; Beige, Joachim

    2004-01-01

    Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure.......Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure....

  7. Output Pressure and Pulse-Echo Characteristics of CMUTs as Function of Plate Dimensions

    DEFF Research Database (Denmark)

    Diederichsen, Søren Elmin; Hansen, Jesper Mark Fly; Engholm, Mathias

    2017-01-01

    This paper presents an experimental study of the acoustic performance of Capacitive Micromachined Ultrasonic Transducers (CMUTs) as function of plate dimensions. The objective is to increase the output pressure without decreasingthe pulse-echo signal. The CMUTs are fabricated with a LOCOS process......-to-peak output pressure and pulse-echo signal is obtained for the 9.3μm plate, which still has a moderate pulseecho bandwidth of 60%. The 9.3μm plate results in a 1.9 times higher peak-to-peak output pressure and a 3.6 times higherpulse-echo signal compared to the 2μm plate. By adjusting the plate dimensions...

  8. Electronic system for recording proportional counter rare pulses with the pulse shape analysis

    International Nuclear Information System (INIS)

    Barabanov, I.R.; Gavrin, V.N.; Zakharov, Yu.I.; Tikhonov, A.A.

    1984-01-01

    The anutomated system for recording proportional counter rare pulses is described. The proportional counters are aimed at identification of 37 Ar and H7 1 Gr decays in chemical radiation detectors of solar neutrino. Pulse shape recording by means of a storage oscilloscope and a TV display is performed in the system considered besides two-parametric selection of events (measurement of pulse amplitude in a slow channel and the amplitude of pulse differentiated with time constant of about 10 ns in a parallel fast channel). Pulse discrimination by a front rise rate provides background decrease in the 55 Fe range (5.9 keV) by 6 times; the visual analysis of pulse shapes recorded allows to decrease the background additionally by 25-30%. The background counting rate in the 55 Fe range being equal to 1 pulse per 1.5 days, is obtained when using the installation described above, as well as the passive Pb shield 5 cm thick, and the active shield based on the anticoincidence NaI(Tl) detector with the cathode 5.6 mm in-diameter made of Fe fabircated by zone melting. The installation described allows to reach the background level of 0.6 pulse/day (the total coefficient of background attenuation is 400). Further background decrease is supposed to be provided by installation allocation in the low-noise underground laboratory of the Baksan Neutrino Observatory

  9. Assessing intravascular volume by difference in pulse pressure in pigs submitted to graded hemorrhage.

    Science.gov (United States)

    Pestel, Gunther J; Hiltebrand, Luzius B; Fukui, Kimiko; Cohen, Delphine; Hager, Helmut; Kurz, Andrea M

    2006-10-01

    We assessed changes in intravascular volume monitored by difference in pulse pressure (dPP%) after stepwise hemorrhage in an experimental pig model. Six pigs (23-25 kg) were anesthetized (isoflurane 1.5 vol%) and mechanically ventilated to keep end-tidal CO2 (etCO2) at 35 mmHg. A PA-catheter and an arterial catheter were placed via femoral access. During and after surgery, animals received lactated Ringer's solution as long as they were considered volume responders (dPP>13%). Then animals were allowed to stabilize from the induction of anesthesia and insertion of catheters for 30 min. After stabilization, baseline measurements were taken. Five percent of blood volume was withdrawn, followed by another 5%, and then in 10%-increments until death from exsanguination occurred. After withdrawal of 5% of blood volume, all pigs were considered volume responders (dPP>13%); dPP rose significantly from 6.1+/-3.3% to 19.4+/-4.2%. The regression analysis of stepwise hemorrhage revealed a linear relation between blood loss (hemorrhage in %) and dPP (y=0.99*x+14; R2=0.7764; P<.0001). In addition, dPP was the only parameter that changed significantly between baseline and a blood loss of 5% (P<0.01), whereas cardiac output, stroke volume, heart rate, MAP, central venous pressure, pulmonary artery occlusion pressure, and systemic vascular resistance, respectively, remained unchanged. We conclude that in an experimental hypovolemic pig model, dPP correlates well with blood loss.

  10. Statistical analysis of random pulse trains

    International Nuclear Information System (INIS)

    Da Costa, G.

    1977-02-01

    Some experimental and theoretical results concerning the statistical properties of optical beams formed by a finite number of independent pulses are presented. The considered waves (corresponding to each pulse) present important spatial variations of the illumination distribution in a cross-section of the beam, due to the time-varying random refractive index distribution in the active medium. Some examples of this kind of emission are: (a) Free-running ruby laser emission; (b) Mode-locked pulse trains; (c) Randomly excited nonlinear media

  11. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    Science.gov (United States)

    Robert, E.; Sarron, V.; Riès, D.; Dozias, S.; Vandamme, M.; Pouvesle, J.-M.

    2012-06-01

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 107-108 cm s-1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications.

  12. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    International Nuclear Information System (INIS)

    Robert, E; Sarron, V; Riès, D; Dozias, S; Vandamme, M; Pouvesle, J-M

    2012-01-01

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 10 7 –10 8 cm s −1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications. (paper)

  13. Spectrometric Analysis for Pulse Jet Mixer Testing

    International Nuclear Information System (INIS)

    ZEIGLER, KRISTINE

    2004-01-01

    The Analytical Development Section (ADS) was tasked with providing support for a Hanford River Protection Program-Waste Treatment Program (RPP-WTP) project test involving absorption analysis for non-Newtonian pulse jet mixer testing for small scale (PJM) and prototype (CRV) tanks with sparging. Tanks filled with clay were mixed with various amounts of powdered dye as a tracer. The objective of the entire project was to determine the best mixing protocol (nozzle velocity, number of spargers used, total air flow, etc.) by determining the percent mixed volume through the use of an ultraviolet-visible (UV-Vis) spectrometer. The dye concentration within the sample could be correlated to the volume fraction mixed in the tank. Samples were received in vials, a series of dilutions were generated from the clay, allowed to equilibrate, then centrifuged and siphoned for the supernate liquid to analyze by absorption spectroscopy. Equilibration of the samples and thorough mixing of the samples were a continuous issue with dilution curves being difficult to obtain. Despite these technical issues, useful data was obtained for evaluation of various mix conditions

  14. Measurement of intraocular pressure using the NT-4000: a new non-contact tonometer equipped with pulse synchronous measurement function.

    Science.gov (United States)

    Yaoeda, Kiyoshi; Shirakashi, Motohiro; Fukushima, Atsushi; Funaki, Shigeo; Funaki, Haruko; Ofuchi, Nobutaka; Nakatsue, Tomoko; Abe, Haruki

    2005-06-01

    NT-4000 (Nidek Co. Ltd., Gamagori, Japan) is a new non-contact tonometer (NCT) equipped with pulse synchronous measurement function that can measure intraocular pressure (IOP) synchronized with the ocular pulse. The purpose of this study was to evaluate the usefulness of NT-4000 in normal subjects and in patients with glaucoma and ocular hypertension. This study included 175 eyes of 175 subjects. Firstly, the IOP was measured using NT-4000 without the pulse synchronous measurement function (NTn). Secondly, the IOP at peak, middle, and trough phases of the pulse signal were measured using NT-4000 with the pulse synchronous measurement function (NTp, NTm, NTt, respectively). Additionally, the IOP was measured with Goldmann applanation tonometer (GT). The coefficient of variation (CV) of three readings in the NCT measurements was used to evaluate the intra-session reproducibility. Statistical comparisons were performed using Wilcoxon signed rank test and one-way analysis of variance with Scheffe's test. Linear regression analysis was used to calculate correlation coefficients. P values less than 0.05 were accepted as statistically significant. The CV of NTn, NTp, NTm, and NTt were 6.4%, 5.5%, 4.9%, and 5.2%, respectively. The CV of NTp, NTm, and NTt were significantly smaller than that of NTn (P = 0.007, P < 0.001, P < 0.001, respectively). NTp was significantly higher than NTt (P = 0.038). GT was significantly correlated with NTn, NTp, NTm, and NTt (r = 0.898, P < 0.001; r = 0.912, P < 0.001; r = 0.908, P < 0.001; r = 0.900, P < 0.001, respectively). NT-4000 can detect the fluctuation of IOP associated with the ocular pulse.

  15. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    International Nuclear Information System (INIS)

    TROYER, G.L.

    2000-01-01

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse rise time versus photo peak position and resolution. These data were collected to investigate the effect of pulse rise time compensation on resolution and efficiency

  16. Acoustic pressure waves induced in human heads by RF pulses from high-field MRI scanners.

    Science.gov (United States)

    Lin, James C; Wang, Zhangwei

    2010-04-01

    The current evolution toward greater image resolution from magnetic resonance image (MRI) scanners has prompted the exploration of higher strength magnetic fields and use of higher levels of radio frequencies (RFs). Auditory perception of RF pulses by humans has been reported during MRI with head coils. It has shown that the mechanism of interaction for the auditory effect is caused by an RF pulse-induced thermoelastic pressure wave inside the head. We report a computational study of the intensity and frequency of thermoelastic pressure waves generated by RF pulses in the human head inside high-field MRI and clinical scanners. The U.S. Food and Drug Administration (U.S. FDA) guides limit the local specific absorption rate (SAR) in the body-including the head-to 8 W kg(-1). We present results as functions of SAR and show that for a given SAR the peak acoustic pressures generated in the anatomic head model were essentially the same at 64, 300, and 400 MHz (1.5, 7.0, and 9.4 T). Pressures generated in the anatomic head are comparable to the threshold pressure of 20 mPa for sound perception by humans at the cochlea for 4 W kg(-1). Moreover, results indicate that the peak acoustic pressure in the brain is only 2 to 3 times the auditory threshold at the U.S. FDA guideline of 8 W kg(-1). Even at a high SAR of 20 W kg(-1), where the acoustic pressure in the brain could be more than 7 times the auditory threshold, the sound pressure levels would not be more than 17 db above threshold of perception at the cochlea.

  17. Unconstrained pulse pressure monitoring for health management using hetero-core fiber optic sensor.

    Science.gov (United States)

    Nishiyama, Michiko; Sonobe, Masako; Watanabe, Kazuhiro

    2016-09-01

    In this paper, we present a pulse pressure waveform sensor that does not constrain a wearer's daily activity; the sensor uses hetero-core fiber optics. Hetero-core fiber sensors have been found to be sensitive to moderate bending. To detect minute pulse pressure changes from the radial artery at the wrist, we devised a fiber sensor arrangement using three-point bending supports. We analyzed and evaluated the measurement validity using wavelet transformation, which is well-suited for biological signal processing. It was confirmed that the detected pulse waveform had a fundamental mode frequency of around 1.25 Hz over the time-varying waveform. A band-pass filter with a range of frequencies from 0.85 to 1.7 Hz was used to pick up the fundamental mode. In addition, a high-pass filter with 0.85 Hz frequency eliminated arm motion artifacts; consequently, we achieved high signal-to-noise ratio. For unrestricted daily health management, it is desirable that pulse pressure monitoring can be achieved by simply placing a device on the hand without the sensor being noticed. Two types of arrangements were developed and demonstrated in which the pulse sensors were either embedded in a base, such as an armrest, or in a wearable device. A wearable device without cuff pressure using a sensitivity-enhanced fiber sensor was successfully achieved with a sensitivity of 0.07-0.3 dB with a noise floor lower than 0.01 dB for multiple subjects.

  18. Comparison of under-pressure and over-pressure pulse tests conducted in low-permeability basalt horizons at the Hanford Site, Washington State

    International Nuclear Information System (INIS)

    Thorne, P.D.; Spane, F.A. Jr.

    1984-10-01

    Over-pressure pulse tests (pressurized slug tests have been widely used by others for hydraulic characterization of low-permeability ( -8 m/sec) rock formations. Recent field studies of low-permeability basalt horizons at the Hanford Site, Washington, indicate that the under-pressure pulse technique is also a viable test method for hydraulic characterization studies. For over-pressure pulse tests, fluid within the test system is rapidly pressurized and the associated pressure decay is monitored as compressed fluid within the test system expands and flows into the test formation. Under-pressure pulse tests are conducted in a similar manner by abruptly decreasing the pressure of fluid within the test system, and monitoring the associated increase in pressure as fluid flows from the formation into the test system. Both pulse test methods have been used in conjunction with other types of tests to determine the hydraulic properties of selected low-permeability basalt horizons at Hanford test sites. Results from both pulse test methods generally provide comparable estimates of hydraulic properties and are in good agreement with those from other tests

  19. Pulse Pressure, Instead of Brachium-Ankle Pulse Wave Velocity, is Associated with Reduced Kidney Function in a Chinese Han Population

    Directory of Open Access Journals (Sweden)

    Linpei Jia

    2017-03-01

    Full Text Available Background/Aims: In this study, we aim to investigate the association between renal function and arterial stiffness in a Chinese Han population, and further to discuss the effects of smoking on renal function. Methods: We collected the data of the brachium-ankle pulse wave velocity (baPWV, blood pressure, blood chemistry and smoking status. Then, the multiple linear regression was done to explore the relationship between estimated glomerular filtration (eGFR and baPWV. Further, the parameters were compared among the four groups divided according to the quartiles of baPWV. Finally, the baPWV, eGFR and albuminuria values were compared between smokers and non-smokers. Results: baPWV is associated with eGFR in the correlation analysis and univariate linear regression model. After adjustment, the pulse pressure (PP instead of baPWV showed a significant association with eGFR. Nevertheless, the eGFR values differed among the four baPWV groups; the baPWV values were significantly higher in the subjects at the CKD (eGFR<60 mL/min/1.73 m2 and the early CKD stage (eGFR60–80 mL/min/1.73 m2. The baPWV values and the ratio of proteinuria were significantly increased in smokers. Conclusion: PP but not baPWV is a predictor of declined renal function. Smokers have worse arterial stiffness and worse renal function.

  20. Pulse Pressure, Instead of Brachium-Ankle Pulse Wave Velocity, is Associated with Reduced Kidney Function in a Chinese Han Population.

    Science.gov (United States)

    Jia, Linpei; Zhang, Weiguang; Ma, Jie; Chen, Xizhao; Chen, Lei; Li, Zuoxiang; Cai, Guangyan; Huang, Jing; Zhang, Jinping; Bai, Xiaojuan; Feng, Zhe; Sun, Xuefeng; Chen, Xiangmei

    2017-01-01

    In this study, we aim to investigate the association between renal function and arterial stiffness in a Chinese Han population, and further to discuss the effects of smoking on renal function. We collected the data of the brachium-ankle pulse wave velocity (baPWV), blood pressure, blood chemistry and smoking status. Then, the multiple linear regression was done to explore the relationship between estimated glomerular filtration (eGFR) and baPWV. Further, the parameters were compared among the four groups divided according to the quartiles of baPWV. Finally, the baPWV, eGFR and albuminuria values were compared between smokers and non-smokers. baPWV is associated with eGFR in the correlation analysis and univariate linear regression model. After adjustment, the pulse pressure (PP) instead of baPWV showed a significant association with eGFR. Nevertheless, the eGFR values differed among the four baPWV groups; the baPWV values were significantly higher in the subjects at the CKD (eGFRfunction. Smokers have worse arterial stiffness and worse renal function. © 2017 The Author(s)Published by S. Karger AG, Basel.

  1. High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

    Science.gov (United States)

    Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

    2016-04-04

    We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ.

  2. Aluminum oxide films deposited in low pressure conditions by reactive pulsed dc magnetron sputtering

    CERN Document Server

    Seino, T

    2002-01-01

    The reactive pulsed dc sputtering technique is widely used for the deposition of oxide films. The operating pressure for sputtering is commonly above 0.13 Pa. In this study, however, aluminum oxide (alumina) films were deposited at operating pressures from 0.06 to 0.4 Pa using a sputtering system equipped with a scanning magnetron cathode and a pulsed dc power supply. The pulsed dc power was found to be useful not only to reduce arcing, but also to sustain the discharge at low pressure. The electrical breakdown field, intrinsic stress, O/Al ratio, refractive index, and surface roughness were investigated. Both a low intrinsic stress and an O/Al ratio around the stoichiometry were required to get the film having a high breakdown field. A low operating pressure of 0.1 Pa was found to provide the necessary stress and O/Al ratio targets. A 50-nm-thick alumina film having a maximum breakdown field of 7.4 MV/cm was obtained.

  3. Effect of high-hydrostatic pressure and moderate-intensity pulsed electric field on plum.

    Science.gov (United States)

    García-Parra, J; González-Cebrino, F; Delgado-Adámez, J; Cava, R; Martín-Belloso, O; Élez-Martínez, P; Ramírez, R

    2018-03-01

    Moderate intensity pulse electric fields were applied in plum with the aim to increase bioactive compounds content of the fruit, while high-hydrostatic pressure was applied to preserve the purées. High-hydrostatic pressure treatment was compared with an equivalent thermal treatment. The addition of ascorbic acid during purée manufacture was also evaluated. The main objective of this study was to assess the effects on microorganisms, polyphenoloxidase, color and bioactive compounds of high-hydrostatic pressure, or thermal-processed plum purées made of moderate intensity pulse electric field-treated or no-moderate intensity pulse electric field-treated plums, after processing during storage. The application of moderate intensity pulse electric field to plums slightly increased the levels of anthocyanins and the antioxidant activity of purées. The application of Hydrostatic-high pressure (HHP) increased the levels of bioactive compounds in purées, while the thermal treatment preserved better the color during storage. The addition of ascorbic acid during the manufacture of plum purée was an important factor for the final quality of purées. The color and the bioactive compounds content were better preserved in purées with ascorbic acid. The no inactivation of polyphenoloxidase enzyme with treatments applied in this study affected the stability purées. Probably more intense treatments conditions (high-hydrostatic pressure and thermal treatment) would be necessary to reach better quality and shelf life during storage.

  4. Dual-modality arterial pulse monitoring system for continuous blood pressure measurement.

    Science.gov (United States)

    Wen-Xuan Dai; Yuan-Ting Zhang; Jing Liu; Xiao-Rong Ding; Ni Zhao

    2016-08-01

    Accurate and ambulatory measurement of blood pressure (BP) is essential for efficient diagnosis, management and prevention of cardiovascular diseases (CVDs). However, traditional cuff-based BP measurement methods provide only intermittent BP readings and can cause discomfort with the occlusive cuff. Although pulse transit time (PTT) method is promising for cuffless and continuous BP measurement, its pervasive use is restricted by its limited accuracy and requirement of placing sensors on multiple body sites. To tackle these issues, we propose a novel dual-modality arterial pulse monitoring system for continuous blood pressure measurement, which simultaneously records the pressure and photoplethysmography (PPG) signals of radial artery. The obtained signals can be used to generate a pressure-volume curve, from which the elasticity index (EI) and viscosity index (VI) can be extracted. Experiments were carried out among 7 healthy subjects with their PPG, ECG, arterial pressure wave and reference BP collected to examine the effectiveness of the proposed indexes. The results of this study demonstrate that a linear regression model combining EI and VI has significantly higher BP tracking correlation coefficient as compared to the PTT method. This suggests that the proposed system and method can potentially be used for convenient and continuous blood pressure estimation with higher accuracy.

  5. Continuous processing of polymers in repetitively pulsed atmospheric pressure discharges with moving surfaces and gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Bhoj, Ananth N [Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801 (United States); Kushner, Mark J [Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2007-11-21

    Atmospheric pressure corona discharges are industrially employed to treat large areas of commodity polymer sheets by creating new surface functional groups. The most common processes use oxygen containing discharges to affix oxygen to hydrocarbon polymers, thereby increasing their surface energy and wettability. The process is typically continuous and is carried out in a web configuration with film speeds of tens to hundreds of cm s{sup -1}. The densities and relative abundances of functional groups depend on the gas composition, gas flow rate and residence time of the polymer in the discharge zone which ultimately determine the magnitude and mole fractions of reactive fluxes to the surface. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of a moving polypropylene sheet in repetitively pulsed He/O{sub 2}/H{sub 2}O discharges. O and OH typically initiate surface processing by hydrogen abstraction. These species are regenerated during every plasma pulse but are also largely consumed during the inter-pulse period. Longer-lived species such as O{sub 3} accumulate over many pulses and convect downstream with the gas flow. Optimizing the interplay between local rapid reactions, such as H abstraction which occurs dominantly in the discharge zone, and non-local slower processes, such as surface-surface reactions, may enable the customization of the relative abundance of surface functional groups.

  6. Continuous processing of polymers in repetitively pulsed atmospheric pressure discharges with moving surfaces and gas flow

    International Nuclear Information System (INIS)

    Bhoj, Ananth N; Kushner, Mark J

    2007-01-01

    Atmospheric pressure corona discharges are industrially employed to treat large areas of commodity polymer sheets by creating new surface functional groups. The most common processes use oxygen containing discharges to affix oxygen to hydrocarbon polymers, thereby increasing their surface energy and wettability. The process is typically continuous and is carried out in a web configuration with film speeds of tens to hundreds of cm s -1 . The densities and relative abundances of functional groups depend on the gas composition, gas flow rate and residence time of the polymer in the discharge zone which ultimately determine the magnitude and mole fractions of reactive fluxes to the surface. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of a moving polypropylene sheet in repetitively pulsed He/O 2 /H 2 O discharges. O and OH typically initiate surface processing by hydrogen abstraction. These species are regenerated during every plasma pulse but are also largely consumed during the inter-pulse period. Longer-lived species such as O 3 accumulate over many pulses and convect downstream with the gas flow. Optimizing the interplay between local rapid reactions, such as H abstraction which occurs dominantly in the discharge zone, and non-local slower processes, such as surface-surface reactions, may enable the customization of the relative abundance of surface functional groups

  7. Twenty-Four-Hour Central Pulse Pressure for Cardiovascular Events Prediction in a Low-Cardiovascular-Risk Population: Results From the Bordeaux Cohort.

    Science.gov (United States)

    Cremer, Antoine; Boulestreau, Romain; Gaillard, Prune; Lainé, Marion; Papaioannou, Georgios; Gosse, Philippe

    2018-02-23

    Central blood pressure (BP) is a promising marker to identify subjects with higher cardiovascular risk than expected by traditional risk factors. Significant results have been obtained in populations with high cardiovascular risk, but little is known about low-cardiovascular-risk patients, although the differences between central and peripheral BP (amplification) are usually greater in this population. The study aim was to evaluate central BP over 24 hours for cardiovascular event prediction in hypertensive subjects with low cardiovascular risk. Peripheral and central BPs were recorded during clinical visits and over 24 hours in hypertensive patients with low cardiovascular risk (Systematic Coronary Risk Evaluation ≤5%). Our primary end point is the occurrence of a cardiovascular event during follow-up. To assess the potential interest in central pulse pressure over 24 hours, we performed Cox proportional hazard models analysis and comparison of area under the curves using the contrast test for peripheral and central BP. A cohort of 703 hypertensive subjects from Bordeaux were included. After the first 24 hours of BP measurement, the subjects were then followed up for an average of 112.5±70 months. We recorded 65 cardiovascular events during follow-up. Amplification was found to be significantly associated with cardiovascular events when added to peripheral 24-hour pulse pressure ( P =0.0259). The area under the curve of 24-hour central pulse pressure is significantly more important than area under the curve of office BP ( P =0.0296), and there is a trend of superiority with the area under the curve of peripheral 24-hour pulse pressure. Central pulse pressure over 24 hours improves the prediction of cardiovascular events for hypertensive patients with low cardiovascular risk compared to peripheral pulse pressure. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  8. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

  9. Numerical Analysis of Through Transmission Pulsed Eddy Current Testing and Effects of Pulse Width Variation

    International Nuclear Information System (INIS)

    Shin, Young Kil; Choi, Dong Myung

    2007-01-01

    By using numerical analysis methods, through transmission type pulsed eddy current (PEC) testing is modeled and PEC signal responses due to varying material conductivity, permeability, thickness, lift-off and pulse width are investigated. Results show that the peak amplitude of PEC signal gets reduced and the time to reach the peak amplitude is increased as the material conductivity, permeability, and specimen thickness increase. Also, they indicate that the pulse width needs to be shorter when evaluating the material conductivity and the plate thickness using the peak amplitude, and when the pulse width is long, the peak time is found to be more useful. Other results related to lift-off variation are reported as well

  10. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    International Nuclear Information System (INIS)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O

    2010-01-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N 2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10 15 cm -3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10 11 cm -3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10 8 cm -3 .

  11. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    Energy Technology Data Exchange (ETDEWEB)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O [Laboratoire EM2C, CNRS UPR288, Ecole Centrale Paris, 92295 Chatenay-Malabry (France)

    2010-12-15

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N{sub 2} (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10{sup 15} cm{sup -3} towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10{sup 11} cm{sup -3} produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10{sup 8} cm{sup -3}.

  12. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    OpenAIRE

    Irena Jeličić; Katarina Lisak; Rajka Božanić

    2012-01-01

    High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF) belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. ...

  13. Systolic Blood Pressure Accuracy Enhancement in the Electronic Palpation Method Using Pulse Waveform

    Science.gov (United States)

    2001-10-25

    adrenalin) or vasodilating (Nipride or Nitromex) medicines. Also painkillers and anesthetics (Oxanest, Diprivan, Fentanyl and Rapifen) may have affected...the measurements. It is hard to distinguish the effects of medication and assess their relation to blood pressure errors and pulse shapes...CONCLUSION During this study, 51 cardiac operated patients were measured to define the effects of arterial stiffening on the accuracy of the

  14. Modelling of pulsed RF corona discharges in high-pressure air

    International Nuclear Information System (INIS)

    Auzas, F; Makarov, M; Naidis, G V

    2012-01-01

    An approach to description of pulsed RF corona discharges in high-pressure air is developed, based on the model of a filamentary discharge sustained by an electromagnetic wave guided along the plasma filament. Results of numerical simulation of spatial-temporal discharge dynamics at the quasi-stationary stage are obtained for various values of gas pressure and wave frequency. Experimental data on the discharge length versus the power absorbed by the discharge are presented. Their comparison with simulation results is given. (paper)

  15. Robust motion artefact resistant circuit for calculation of Mean Arterial Pressure from pulse transit time.

    Science.gov (United States)

    Bhattacharya, Tinish; Gupta, Ankesh; Singh, Salam ThoiThoi; Roy, Sitikantha; Prasad, Anamika

    2017-07-01

    Cuff-less and non-invasive methods of Blood Pressure (BP) monitoring have faced a lot of challenges like stability, noise, motion artefact and requirement for calibration. These factors are the major reasons why such devices do not get approval from the medical community easily. One such method is calculating Blood Pressure indirectly from pulse transit time (PTT) obtained from electrocardiogram (ECG) and Photoplethysmogram (PPG). In this paper we have proposed two novel analog signal conditioning circuits for ECG and PPG that increase stability, remove motion artefacts, remove the sinusoidal wavering of the ECG baseline due to respiration and provide consistent digital pulses corresponding to blood pulses/heart-beat. We have combined these two systems to obtain the PTT and then correlated it with the Mean Arterial Pressure (MAP). The aim was to perform major part of the processing in analog domain to decrease processing load over microcontroller so as to reduce cost and make it simple and robust. We have found from our experiments that the proposed circuits can calculate the Heart Rate (HR) with a maximum error of ~3.0% and MAP with a maximum error of ~2.4% at rest and ~4.6% in motion.

  16. A Novel Interpretation for Arterial Pulse Pressure Amplification in Health and Disease

    Directory of Open Access Journals (Sweden)

    Manuel R. Alfonso

    2018-01-01

    Full Text Available Arterial pressure waves have been described in one dimension using several approaches, such as lumped (Windkessel or distributed (using Navier-Stokes equations models. An alternative approach consists of modeling blood pressure waves using a Korteweg-de Vries (KdV equation and representing pressure waves as combinations of solitons. This model captures many key features of wave propagation in the systemic network and, in particular, pulse pressure amplification (PPA, which is a mechanical biomarker of cardiovascular risk. The main objective of this work is to compare the propagation dynamics described by a KdV equation in a human-like arterial tree using acquired pressure waves. Furthermore, we analyzed the ability of our model to reproduce induced elastic changes in PPA due to different pathological conditions. To this end, numerical simulations were performed using acquired central pressure signals from different subject groups (young, adults, and hypertensive as input and then comparing the output of the model with measured radial artery pressure waveforms. Pathological conditions were modeled as changes in arterial elasticity (E. Numerical results showed that the model was able to propagate acquired pressure waveforms and to reproduce PPA variations as a consequence of elastic changes. Calculated elasticity for each group was in accordance with the existing literature.

  17. The effects of balneotherapy on blood pressure and pulse in osteoarthritis patients with hypertension.

    Science.gov (United States)

    Umay, Ebru; Tezelli, Mustafa Kemal; Meshur, Mehmet; Umay, Serkan

    2013-01-01

    Balneotherapy is a treatment modality that uses the physical and chemical effects of water, including thermomineral, acratothermal, and acratopegal waters. Although balneotherapy is an ancient treatment method that has a limited use within current treatment modalities, it is still widely popular with the public. Studies usually have reported that balneotherapy is associated with an increased risk of complications, especially in patients with hypertension (HT). The research team intended this study to evaluate the effects of balneotherapy on peripheral, arterial blood pressure and pulse in osteoarthritis (OA) patients with HT, compared to normotensive patients. For the current study, the research team examined the medical records of 5814 patients who were hospitalized and treated for OA at the team's institution between 2008 and 2010. This examination involved a review of the evaluation form that a nurse had obtained when those patients entered the hospital. This study was done at a balneotherapy hospital. Participants were 2090 individuals, including 1036 (49.6%) with primary (essential) HT and 1054 (50.4%) normotensives, with OA of the lumbosacral region, knee, hand, and foot. All participants received balneotherapy at the same time every day (10:00-10:30 AM) for 20 min/d, 5 d/wk, for a total duration of 15 d. Following balneotherapy, all participants performed an exercise program consisting of range of motion (ROM) and stretching exercises. Measurements of pulse and systolic and diastolic blood pressures were recorded before treatment and after 15 sessions of balneotherapy. Within-group and between-group comparisons of results of pulse and systolic and diastolic blood pressure measurements were performed. The study found a significant reduction after treatment in systolic and diastolic blood pressures in both normotensive and HT participants. Moreover, the reduction in diastolic blood pressure was noted to be greater in the HT group (P = .046). Balneotherapy may

  18. Comparison of Regression Analysis and Transfer Function in Estimating the Parameters of Central Pulse Waves from Brachial Pulse Wave.

    Science.gov (United States)

    Chai, Rui; Xu, Li-Sheng; Yao, Yang; Hao, Li-Ling; Qi, Lin

    2017-01-01

    This study analyzed ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO), and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. Invasively measured parameters were compared with parameters measured from brachial pulse waves by regression model and transfer function model. Accuracy of parameters estimated by regression and transfer function model, was compared too. Findings showed that k value, central pulse wave and brachial pulse wave parameters invasively measured, correlated positively. Regression model parameters including A_slope, DBP, SEVR, and transfer function model parameters had good consistency with parameters invasively measured. They had same effect of consistency. SBP, PP, SV, and CO could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

  19. Application of dynamic response analysis to JET heat pulse data

    International Nuclear Information System (INIS)

    Griguoli, A.; Sips, A.C.C.

    1993-09-01

    The plasma dynamic response can be used to study transport processes in a tokamak plasma. A method has been developed for the application of dynamic response analysis to study perturbations away from the plasma equilibrium. In this report perturbations on the electron temperature following a sawtooth collapse in the center of the plasma are considered. The method has been used to find mathematical description of a series of heat pulses at the Joint European Torus project (JET). From the plasma dynamic response, the time constants which characterise the heat pulse are obtained. These time constants are compared to the transport coefficients found in previous analysis of the JET heat pulse data. Various methods are discussed for applying dynamic response analysis to JET heat pulse data. (author)

  20. Social support and loneliness in college students: effects on pulse pressure reactivity to acute stress.

    Science.gov (United States)

    O'Donovan, Aoife; Hughes, Brian

    2007-01-01

    Socially supportive relationships at university may buffer against psychological stress in students, particularly in those experiencing loneliness. To examine the relation of social support at university and loneliness with pulse pressure (PP) reactivity to acute psychological stress in a sample of first-year undergraduate students. Sixty-five female, adolescent, first-year university students. Pulse pressure (PP) was calculated as the arithmetic difference between systolic blood pressure and diastolic blood pressure, which were measured during a resting baseline and during a stressful reading task. The difference between baseline and reading task PP represents PP reactivity. The Social Support at University Scale (SSUS) was used to assess social support availability in university, and the Revised UCLA Loneliness Scale was used to assess loneliness. Hierarchical linear regression was used to examine main and interactive effects of SSUS and loneliness on PP change scores, and simple slopes were computed to assist in the interpretation of interaction effects. Social support at university was associated with lower PP reactivity in students reporting medium (t = -2.03, p = .04) or high levels of loneliness (t = -2.93, p = .004), but not in those reporting low levels of loneliness (t = -0.20, p = .83). Psychosocial interventions designed to increase social support available at university, and targeted at students experiencing loneliness may buffer against the harmful effects of acute stressors in lonely first-year students.

  1. An Investigation of Pulse Transit Time as a Non-Invasive Blood Pressure Measurement Method

    International Nuclear Information System (INIS)

    McCarthy, B M; O'Flynn, B; Mathewson, A

    2011-01-01

    The objective of this paper is to examine the Pulse Transit Method (PTT) as a non-invasive means to track Blood Pressure over a short period of time. PTT was measured as the time it takes for an ECG R-wave to propagate to the finger, where it is detected by a photoplethysmograph sensor. The PTT method is ideal for continuous 24-hour Blood Pressure Measurement (BPM) since it is both cuff-less and non-invasive and therefore comfortable and unobtrusive for the patient. Other techniques, such as the oscillometric method, have shown to be accurate and reliable but require a cuff for operation, making them unsuitable for long term monitoring. Although a relatively new technique, the PTT method has shown to be able to accurately track blood pressure changes over short periods of time, after which re-calibration is necessary. The purpose of this study is to determine the accuracy of the method.

  2. AUTOMATIC DETECTION ALGORITHM OF DYNAMIC PRESSURE PULSES IN THE SOLAR WIND

    International Nuclear Information System (INIS)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Li, Huijun; Xu, Xiaojun

    2015-01-01

    Dynamic pressure pulses (DPPs) in the solar wind are a significant phenomenon closely related to the solar-terrestrial connection and physical processes of solar wind dynamics. In order to automatically identify DPPs from solar wind measurements, we develop a procedure with a three-step detection algorithm that is able to rapidly select DPPs from the plasma data stream and simultaneously define the transition region where large dynamic pressure variations occur and demarcate the upstream and downstream region by selecting the relatively quiet status before and after the abrupt change in dynamic pressure. To demonstrate the usefulness, efficiency, and accuracy of this procedure, we have applied it to the Wind observations from 1996 to 2008 by successfully obtaining the DPPs. The procedure can also be applied to other solar wind spacecraft observation data sets with different time resolutions

  3. Nanosecond pulsed laser nanostructuring of Au thin films: Comparison between irradiation at low and atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Aké, C., E-mail: citlali.sanchez@ccadet.unam.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico); Canales-Ramos, A. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico); García-Fernández, T. [Universidad Autónoma de la Ciudad de México (UACM), Prolongación San Isidro 151, Col. San Lorenzo Tezonco, México D.F., C.P. 09790 (Mexico); Villagrán-Muniz, M. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, C. U., Delegación Coyoacán, C.P. 04510, México D.F. (Mexico)

    2017-05-01

    Highlights: • Background pressure plays an important role in NPs formation and its characteristics. • The NPs diameter and their size dispersion are smaller when irradiating in vacuum. • The plasmon resonance shifts ∼15 nm to higher frequencies when irradiating in vacuum. • Film partial ablation cannot be neglected for thickness in the range 40–80 nm. • In situ optical techniques monitor the timescale of the process and ablation dynamics. - Abstract: Au thin films with tens of nm in thickness deposited on glass substrates were irradiated with nanosecond UV (355 nm) laser pulses at atmospheric pressure and in vacuum conditions (∼600 and 10{sup −5} Torr). We studied the effect of the laser fluence (200–400 mJ/cm{sup 2}), thickness of the starting film (∼40–80 nm) and surrounding pressure on the partial ablation/evaporation of the films and the morphology of the produced nanoparticles (NPs). The dynamics of NPs formation was studied by measuring in real time the transmission of the samples upon continuous-wave laser exposure, and by means of probe beam deflection technique. The ejection of material from the film as a result of the irradiation was confirmed by time-resolved shadowgraphy technique. Experiments show that the NPs diameter and their size distribution are smaller when the irradiation is performed in vacuum regardless the laser fluence and thickness of the started film. It is also shown that the plasmon band shifts to higher frequencies with lower background pressure. The optical measurements show that the films melt and ablate during the laser pulse, but the transmission of the irradiated areas continues changing during tens of microseconds due to ejection of material and solidification of the remaining gold. Our results indicate that partial ablation cannot be neglected in nanostructuration by ns-pulsed irradiation of thin films when their thickness is in the studied range.

  4. Pressure thermal shock analysis for nuclear reactor pressure vessel

    International Nuclear Information System (INIS)

    Galik, G.; Kutis, V.; Jakubec, J.; Paulech, J.; Murin, J.

    2015-01-01

    The appearance of structural weaknesses within the reactor pressure vessel or its structural failure caused by crack formation during pressure thermal shock processes pose as a severe environmental hazard. Coolant mixing during ECC cold water injection was simulated in a detailed CFD analysis. The temperature distribution acting on the pipe wall internal surface was calculated. Although, the results show the formation of high temperature differences and intense gradients, an additional structural analysis is required to determine the possibility of structural damage from PTS. Such an analysis will be the subject of follow-up research. (authors)

  5. Research on digital multi-channel pulse height analysis techniques

    International Nuclear Information System (INIS)

    Xiao Wuyun; Wei Yixiang; Ai Xianyun; Ao Qi

    2005-01-01

    Multi-channel pulse height analysis techniques are developing in the direction of digitalization. Based on digital signal processing techniques, digital multi-channel analyzers are characterized by powerful pulse processing ability, high throughput, improved stability and flexibility. This paper analyzes key techniques of digital nuclear pulse processing. With MATLAB software, main algorithms are simulated, such as trapezoidal shaping, digital baseline estimation, digital pole-zero/zero-pole compensation, poles and zeros identification. The preliminary general scheme of digital MCA is discussed, as well as some other important techniques about its engineering design. All these lay the foundation of developing homemade digital nuclear spectrometers. (authors)

  6. Pulse Combustor Driven Pressure Gain Combustion for High Efficiency Gas Turbine Engines

    KAUST Repository

    Lisanti, Joel

    2017-02-01

    The gas turbine engine is an essential component of the global energy infrastructure which accounts for a significant portion of the total fossil fuel consumption in transportation and electric power generation sectors. For this reason there is significant interest in further increasing the efficiency and reducing the pollutant emissions of these devices. Conventional approaches to this goal, which include increasing the compression ratio, turbine inlet temperature, and turbine/compressor efficiency, have brought modern gas turbine engines near the limits of what may be achieved with the conventionally applied Brayton cycle. If a significant future step increase in gas turbine efficiency is to be realized some deviation from this convention is necessary. The pressure gain gas turbine concept is a well established new combustion technology that promises to provide a dramatic increase in gas turbine efficiency by replacing the isobaric heat addition process found in conventional technology with an isochoric process. The thermodynamic benefit of even a small increase in stagnation pressure across a gas turbine combustor translates to a significant increase in cycle efficiency. To date there have been a variety of methods proposed for achieving stagnation pressure gains across a gas turbine combustor and these concepts have seen a broad spectrum of levels of success. The following chapter provides an introduction to one of the proposed pressure gain methods that may be most easily realized in a practical application. This approach, known as pulse combustor driven pressure gain combustion, utilizes an acoustically resonant pulse combustor to approximate isochoric heat release and thus produce a rise in stagnation pressure.

  7. The effects of pulse pressure from seismic water gun technology on Northern Pike

    Science.gov (United States)

    Gross, Jackson A.; Irvine, Kathryn M.; Wilmoth, Siri K.; Wagner, Tristany L.; Shields, Patrick A; Fox, Jeffrey R.

    2013-01-01

    We examined the efficacy of sound pressure pulses generated from a water gun for controlling invasive Northern Pike Esox lucius. Pulse pressures from two sizes of water guns were evaluated for their effects on individual fish placed at a predetermined random distance. Fish mortality from a 5,620.8-cm3 water gun (peak pressure source level = 252 dB referenced to 1 μP at 1 m) was assessed every 24 h for 168 h, and damage (intact, hematoma, or rupture) to the gas bladder, kidney, and liver was recorded. The experiment was replicated with a 1,966.4-cm3 water gun (peak pressure source level = 244 dB referenced to 1 μP at 1 m), but fish were euthanized immediately. The peak sound pressure level (SPLpeak), peak-to-peak sound pressure level (SPLp-p), and frequency spectrums were recorded, and the cumulative sound exposure level (SELcum) was subsequently calculated. The SPLpeak, SPLp-p, and SELcum were correlated, and values varied significantly by treatment group for both guns. Mortality increased and organ damage was greater with decreasing distance to the water gun. Mortality (31%) by 168 h was only observed for Northern Pike exhibiting the highest degree of organ damage. Mortality at 72 h and 168 h postexposure was associated with increasing SELcum above 195 dB. The minimum SELcum calculated for gas bladder rupture was 199 dB recorded at 9 m from the 5,620.8-cm3 water gun and 194 dB recorded at 6 m from the 1,966.4-cm3water gun. Among Northern Pike that were exposed to the large water gun, 100% of fish exposed at 3 and 6 m had ruptured gas bladders, and 86% exposed at 9 m had ruptured gas bladders. Among fish that were exposed to pulse pressures from the smaller water gun, 78% exhibited gas bladder rupture. Results from these initial controlled experiments underscore the potential of water guns as a tool for controlling Northern Pike.

  8. Plasma sterilization of polyethylene terephthalate bottles by pulsed corona discharge at atmospheric pressure.

    Science.gov (United States)

    Masaoka, Satoshi

    2007-06-01

    A pulsed power supply was used to generate a corona discharge on a polyethylene terephthalate bottle, to conduct plasma sterilization at atmospheric pressure. Before generating such a discharge, minute quantities of water were attached to the inner surface of the bottle and to the surface of a high voltage (HV) electrode inserted into the bottle. Next, high-voltage pulses of electricity were discharged between electrodes for 6.0s, while rotating the bottle. The resulting spore log reduction values of Bacillus subtilis and Aspergillus niger on the inner surface of the bottle were 5.5 and 6 or higher, respectively, and those on the HV electrode surface were each 6 or higher for both strains. The presence of the by-products gaseous ozone, hydrogen peroxide, and nitric ions resulting from the electrical discharge was confirmed.

  9. Low-pressure pulsed focused ultrasound with microbubbles promotes an anticancer immunological response.

    Science.gov (United States)

    Liu, Hao-Li; Hsieh, Han-Yi; Lu, Li-An; Kang, Chiao-Wen; Wu, Ming-Fang; Lin, Chun-Yen

    2012-11-11

    High-intensity focused-ultrasound (HIFU) has been successfully employed for thermal ablation of tumors in clinical settings. Continuous- or pulsed-mode HIFU may also induce a host antitumor immune response, mainly through expansion of antigen-presenting cells in response to increased cellular debris and through increased macrophage activation/infiltration. Here we demonstrated that another form of focused ultrasound delivery, using low-pressure, pulsed-mode exposure in the presence of microbubbles (MBs), may also trigger an antitumor immunological response and inhibit tumor growth. A total of 280 tumor-bearing animals were subjected to sonographically-guided FUS. Implanted tumors were exposed to low-pressure FUS (0.6 to 1.4 MPa) with MBs to increase the permeability of tumor microvasculature. Tumor progression was suppressed by both 0.6 and 1.4-MPa MB-enhanced FUS exposures. We observed a transient increase in infiltration of non-T regulatory (non-Treg) tumor infiltrating lymphocytes (TILs) and continual infiltration of CD8+ cytotoxic T-lymphocytes (CTL). The ratio of CD8+/Treg increased significantly and tumor growth was inhibited. Our findings suggest that low-pressure FUS exposure with MBs may constitute a useful tool for triggering an anticancer immune response, for potential cancer immunotherapy.

  10. Vapor Pressure Data Analysis and Statistics

    Science.gov (United States)

    2016-12-01

    near 8, 2000, and 200, respectively. The A (or a) value is directly related to vapor pressure and will be greater for high vapor pressure materials...1, (10) where n is the number of data points, Yi is the natural logarithm of the i th experimental vapor pressure value, and Xi is the...VAPOR PRESSURE DATA ANALYSIS AND STATISTICS ECBC-TR-1422 Ann Brozena RESEARCH AND TECHNOLOGY DIRECTORATE

  11. Effects of Roselle on arterial pulse pressure and left ventricular hypertrophy in hypertensive patients.

    Science.gov (United States)

    Al-Shafei, Ahmad I; El-Gendy, Ola A

    2013-12-01

    To characterize the effects of regular Roselle ingestion on blood pressure and left ventricular hypertrophy (LVH) in patients with established moderate essential hypertension. This non-randomized quasi-experimental study was conducted in Kafr El-Shaikh, Egypt, for 8 weeks, from September 2012 to November 2012. The effects of a 4-week period of regular Roselle ingestion followed by a 4-week recovery period on systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and heart rates (HR) was studied in 2 equal, gender- and age-matched groups (n=50 each; average age - 50+/-5 years) of normotensive subjects, and patients with moderate essential hypertension. Electrocardiographic assessments of LVH were also made prior to, and at the end of both treatment and recovery periods. Pulse pressure (PP) significantly fell from baseline values by 10.9% (normotensive group [NG]), 21.2% (hypertensive group [HG]); SBP by 10% (NG), 19.6% (HG); DBP by 9.5% (NG), 18.7% (HG), and HR by 14.6% (NG), 17.1% (HG) by the end of week 4 of treatment. Following treatment cessation, SBP, DBP, PP, and HR returned to pretreatment levels over 4 weeks. Before intervention, none of the normotensive subjects, but 14 hypertensive patients showed LVH. However, Roselle treatment was associated with regression of LVH in 10 patients with only 4 patients showing LVH after 4 weeks of treatment. This became 10 patients 4 weeks after ceasing treatment. These findings empirically suggest favorable cardiovascular effects of Roselle in patients with established moderate essential hypertension.

  12. The association between brain-derived neurotrophic factor and central pulse pressure after an oral glucose tolerance test.

    Science.gov (United States)

    Lee, I-Te; Chen, Chen-Huan; Wang, Jun-Sing; Fu, Chia-Po; Lee, Wen-Jane; Liang, Kae-Woei; Lin, Shih-Yi; Sheu, Wayne Huey-Herng

    2018-01-01

    Arterial stiffening blunts postprandial vasodilatation. We hypothesized that brain-derived neurotrophic factor (BDNF) may modulate postprandial central pulse pressure, a surrogate marker for arterial stiffening. A total of 82 non-diabetic subjects received a 75-g oral glucose tolerance test (OGTT) after overnight fasting. Serum BDNF concentrations were determined at 0, 30, and 120min to calculate the area under the curve (AUC). Brachial and central blood pressures were measured using a noninvasive central blood pressure monitor before blood withdrawals at 0 and 120min. With the median AUC of BDNF of 45(ng/ml)∗h as the cutoff value, the central pulse pressure after glucose intake was significantly higher in the subjects with a low BDNF than in those with a high BDNF (63±16 vs. 53±11mmHg, P=0.003), while the brachial pulse pressure was not significantly different between the 2 groups (P=0.099). In a multivariate linear regression model, a lower AUC of BDNF was an independent predictor of a higher central pulse pressure after oral glucose intake (linear regression coefficient-0.202, 95% confidence interval-0.340 to -0.065, P=0.004). After oral glucose challenge, a lower serum BDNF response is significantly associated with a higher central pulse pressure. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Stable radiation pressure acceleration of ions by suppressing transverse Rayleigh-Taylor instability with multiple Gaussian pulses

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, M. L.; Liu, B.; Hu, R. H.; Shou, Y. R.; Lin, C.; Lu, H. Y.; Lu, Y. R.; Ma, W. J., E-mail: wenjun.ma@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, CAPT, Peking University, Beijing 100871 (China); Gu, Y. Q. [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Yan, X. Q., E-mail: x.yan@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, and Key Laboratory of HEDP of the Ministry of Education, CAPT, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China)

    2016-08-15

    In the case of a thin plasma slab accelerated by the radiation pressure of an ultra-intense laser pulse, the development of Rayleigh-Taylor instability (RTI) will destroy the acceleration structure and terminate the acceleration process much sooner than theoretical limit. In this paper, a new scheme using multiple Gaussian pulses for ion acceleration in a radiation pressure acceleration regime is investigated with particle-in-cell simulation. We found that with multiple Gaussian pulses, the instability could be efficiently suppressed and the divergence of the ion bunch is greatly reduced, resulting in a longer acceleration time and much more collimated ion bunch with higher energy than using a single Gaussian pulse. An analytical model is developed to describe the suppression of RTI at the laser-plasma interface. The model shows that the suppression of RTI is due to the introduction of the long wavelength mode RTI by the multiple Gaussian pulses.

  14. Outcome-driven thresholds for ambulatory pulse pressure in 9938 participants recruited from 11 populations

    DEFF Research Database (Denmark)

    Gu, Yu-Mei; Thijs, Lutgarde; Li, Yan

    2014-01-01

    Evidence-based thresholds for risk stratification based on pulse pressure (PP) are currently unavailable. To derive outcome-driven thresholds for the 24-hour ambulatory PP, we analyzed 9938 participants randomly recruited from 11 populations (47.3% women). After age stratification (... interval of the HRs associated with stepwise increasing PP levels crossed unity at 64 mm Hg. While accounting for all covariables, the top tenth of PP contributed less than 0.3% (generalized R(2) statistic) to the overall risk among the elderly. Thus, in randomly recruited people, ambulatory PP does...

  15. Consumer acceptance of high-pressure processing and pulsed-electric-field

    DEFF Research Database (Denmark)

    Olsen, Nina Veflen; Grunert, Klaus G.; Sonne, Anne-Mette

    2010-01-01

    New products and new processing techniques are continuously developed in the food industry. While food scientists may focus on the technical novelty and applaud the progress of science, consumers are often conservative and sceptical towards changes. The advantages that a new processing technology...... has to offer, do not necessarily guarantee the success of a product in the market place. Consumer acceptance depends on whether consumers perceive that there are specific benefits associated with the product. This review focuses specifically on how high-pressure processing (HPP) and pulsed...

  16. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Duten, X; Redolfi, M; Aggadi, N; Vega, A; Hassouni, K, E-mail: duten@lspm.cnrs.fr [LSPM-CNRS UPR 3407, Universite Paris Nord, 90 Avenue J.B. Clement, 93430 Villetaneuse (France)

    2011-10-19

    This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.

  17. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure

    Science.gov (United States)

    Duten, X.; Redolfi, M.; Aggadi, N.; Vega, A.; Hassouni, K.

    2011-10-01

    This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.

  18. Spatial and temporal evolutions of ozone in a nanosecond pulse corona discharge at atmospheric pressure

    International Nuclear Information System (INIS)

    Duten, X; Redolfi, M; Aggadi, N; Vega, A; Hassouni, K

    2011-01-01

    This paper deals with the experimental determination of the spatial and temporal evolutions of the ozone concentration in an atmospheric pressure pulsed plasma, working in the nanosecond regime. We observed that ozone was produced in the localized region of the streamer. The ozone transport requires a characteristic time well above the millisecond. The numerical modelling of the streamer expansion confirms that the hydrodynamic expansion of the filamentary discharge region during the streamer propagation does not lead to a significant transport of atomic oxygen and ozone. It appears therefore that only diffusional transport can take place, which requires a characteristic time of the order of 50 ms.

  19. HARMONIC ANALYSIS OF SVPWM INVERTER USING MULTIPLE-PULSES METHOD

    Directory of Open Access Journals (Sweden)

    Mehmet YUMURTACI

    2009-01-01

    Full Text Available Space Vector Modulation (SVM technique is a popular and an important PWM technique for three phases voltage source inverter in the control of Induction Motor. In this study harmonic analysis of Space Vector PWM (SVPWM is investigated using multiple-pulses method. Multiple-Pulses method calculates the Fourier coefficients of individual positive and negative pulses of the output PWM waveform and adds them together using the principle of superposition to calculate the Fourier coefficients of the all PWM output signal. Harmonic magnitudes can be calculated directly by this method without linearization, using look-up tables or Bessel functions. In this study, the results obtained in the application of SVPWM for values of variable parameters are compared with the results obtained with the multiple-pulses method.

  20. Transient thermal analysis of semiconductor diode lasers under pulsed operation

    Science.gov (United States)

    Veerabathran, G. K.; Sprengel, S.; Karl, S.; Andrejew, A.; Schmeiduch, H.; Amann, M.-C.

    2017-02-01

    Self-heating in semiconductor lasers is often assumed negligible during pulsed operation, provided the pulses are `short'. However, there is no consensus on the upper limit of pulse width for a given device to avoid-self heating. In this paper, we present an experimental and theoretical analysis of the effect of pulse width on laser characteristics. First, a measurement method is introduced to study thermal transients of edge-emitting lasers during pulsed operation. This method can also be applied to lasers that do not operate in continuous-wave mode. Secondly, an analytical thermal model is presented which is used to fit the experimental data to extract important parameters for thermal analysis. Although commercial numerical tools are available for such transient analyses, this model is more suitable for parameter extraction due to its analytical nature. Thirdly, to validate this approach, it was used to study a GaSb-based inter-band laser and an InP-based quantum cascade laser (QCL). The maximum pulse-width for less than 5% error in the measured threshold currents was determined to be 200 and 25 ns for the GaSb-based laser and QCL, respectively.

  1. Pressurized Thermal Shock Analysis for OPR1000 Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, P. K.; Shamim, J. A.; Gairola, A.; Suh, Kune Y. [Seoul National Univ., Seoul (Korea, Republic of)

    2014-10-15

    The study provides a brief understanding of the analysis procedure and techniques using ANSYS, such as the acceptance criteria, selection and categorization of events, thermal analysis, structural analysis including fracture mechanics assessment, crack propagation and evaluation of material properties. PTS may result from instrumentation and control malfunction, inadvertent steam dump, and postulated accidents such as smallbreak (SB) LOCA, large-break (LB) LOCA, main steam line break (MSLB), feedwater line breaks and steam generator overfill. In this study our main focus is to consider only the LB LOCA due to a cold leg break of the Optimized Power Reactor 1000 MWe (OPR1000). Consideration is given as well to the emergency core cooling system (ECCS) specific sequence with the operating parameters like pressure, temperature and time sequences. The static structural and thermal analysis to investigate the effects of PTS on RPV is the main motivation of this study. Specific surface crack effects and its propagation is also considered to measure the integrity of the RPV. This study describes the procedure for pressurized thermal shock analysis due to a loss of coolant accidental condition and emergency core cooling system operation for reactor pressure vessel.. Different accidental events that cause pressurized thermal shock to nuclear RPV that can also be analyzed in the same way. Considering the limitations of low speed computer only the static analysis is conducted. The modified LBLOCA phases and simplified geometry can is utilized to analyze the effect of PTS on RPV for general understanding not for specific specialized purpose. However, by integrating the disciplines of thermal and structural analysis, and fracture mechanics analysis a clearer understanding of the total aspect of the PTS problem has resulted. By adopting the CFD, thermal hydraulics, uncertainties and risk analysis for different type of accidental conditions, events and sequences with proper

  2. Plasma density enhancement in atmospheric-pressure dielectric-barrier discharges by high-voltage nanosecond pulse in the pulse-on period: a PIC simulation

    International Nuclear Information System (INIS)

    Sang Chaofeng; Sun Jizhong; Wang Dezhen

    2010-01-01

    A particle-in-cell (PIC) plus Monte Carlo collision simulation is employed to investigate how a sustainable atmospheric pressure single dielectric-barrier discharge responds to a high-voltage nanosecond pulse (HVNP) further applied to the metal electrode. The results show that the HVNP can significantly increase the plasma density in the pulse-on period. The ion-induced secondary electrons can give rise to avalanche ionization in the positive sheath, which widens the discharge region and enhances the plasma density drastically. However, the plasma density stops increasing as the applied pulse lasts over certain time; therefore, lengthening the pulse duration alone cannot improve the discharge efficiency further. Physical reasons for these phenomena are then discussed.

  3. Plasma density enhancement in atmospheric-pressure dielectric-barrier discharges by high-voltage nanosecond pulse in the pulse-on period: a PIC simulation

    Science.gov (United States)

    Sang, Chaofeng; Sun, Jizhong; Wang, Dezhen

    2010-02-01

    A particle-in-cell (PIC) plus Monte Carlo collision simulation is employed to investigate how a sustainable atmospheric pressure single dielectric-barrier discharge responds to a high-voltage nanosecond pulse (HVNP) further applied to the metal electrode. The results show that the HVNP can significantly increase the plasma density in the pulse-on period. The ion-induced secondary electrons can give rise to avalanche ionization in the positive sheath, which widens the discharge region and enhances the plasma density drastically. However, the plasma density stops increasing as the applied pulse lasts over certain time; therefore, lengthening the pulse duration alone cannot improve the discharge efficiency further. Physical reasons for these phenomena are then discussed.

  4. Evaluation of the health status of six volunteers from the Mars 500 project using pulse analysis.

    Science.gov (United States)

    Shi, Hong-Zhi; Fan, Quan-Chun; Gao, Jian-Yi; Liu, Jun-Lian; Bai, Gui-E; Mi, Tao; Zhao, Shuang; Liu, Yu; Xu, Dong; Guo, Zhi-Feng; Li, Yong-Zhi

    2017-08-01

    To comprehensively evaluate the health status of 6 volunteers from the Mars 500 Project through analyzing their pulse graphs and determining the changes in cardiovascular function, degree of fatigue and autonomic nervous function. Six volunteers were recruited; all were male aged 26-38 years (average 31.83±4.96 years). Characteristic parameters reflflecting the status of cardiovascular functions were extracted, which included left ventricular contraction, vascular elasticity and peripheral resistance. The degree of fatigue was determined depending on the difference between the calendar age and biological age, which was calculated through the analysis of blood pressure value and characteristic parameters. Based on the values of pulse height variation and pulse time variation on a 30-s pulse graph, autonomic nervous function was evaluated. All parameters examined were marked on an equilateral polygon to form an irregular polygon of the actual fifigure, then health status was evaluated based on the coverage area of the actual fifigure. The results demonstrated: (1) volunteers developed weakened pulse power, increased vascular tension and peripheral resistance, and slight decreased ventricular systolic function; (2) the degree of fatigue was basically mild or moderate; and (3) autonomic nervous function was excited but generally balanced. These volunteers were in the state of sub-health. According to Chinese medicine theories, such symptoms are mainly caused by the weakening of healthy qi, Gan (Liver) failing in free coursing, and disharmony between Gan and Wei (Stomach), which manifests as a weak and string-like pulse.

  5. Predicting blood transfusion using automated analysis of pulse oximetry signals and laboratory values.

    Science.gov (United States)

    Shackelford, Stacy; Yang, Shiming; Hu, Peter; Miller, Catriona; Anazodo, Amechi; Galvagno, Samuel; Wang, Yulei; Hartsky, Lauren; Fang, Raymond; Mackenzie, Colin

    2015-10-01

    Identification of hemorrhaging trauma patients and prediction of blood transfusion needs in near real time will expedite care of the critically injured. We hypothesized that automated analysis of pulse oximetry signals in combination with laboratory values and vital signs obtained at the time of triage would predict the need for blood transfusion with accuracy greater than that of triage vital signs or pulse oximetry analysis alone. Continuous pulse oximetry signals were recorded for directly admitted trauma patients with abnormal prehospital shock index (heart rate [HR] / systolic blood pressure) of 0.62 or greater. Predictions of blood transfusion within 24 hours were compared using Delong's method for area under the receiver operating characteristic (AUROC) curves to determine the optimal combination of triage vital signs (prehospital HR + systolic blood pressure), pulse oximetry features (40 waveform features, O2 saturation, HR), and laboratory values (hematocrit, electrolytes, bicarbonate, prothrombin time, international normalization ratio, lactate) in multivariate logistic regression models. We enrolled 1,191 patients; 339 were excluded because of incomplete data; 40 received blood within 3 hours; and 14 received massive transfusion. Triage vital signs predicted need for transfusion within 3 hours (AUROC, 0.59) and massive transfusion (AUROC, 0.70). Pulse oximetry for 15 minutes predicted transfusion more accurately than triage vital signs for both time frames (3-hour AUROC, 0.74; p = 0.004) (massive transfusion AUROC, 0.88; p transfusion prediction (3-hour AUROC, 0.84; p transfusion AUROC, 0.91; p blood transfusion during trauma resuscitation more accurately than triage vital signs or pulse oximetry analysis alone. Results suggest automated calculations from a noninvasive vital sign monitor interfaced with a point-of-care laboratory device may support clinical decisions by recognizing patients with hemorrhage sufficient to need transfusion. Epidemiologic

  6. Study on the mode-transition of nanosecond-pulsed dielectric barrier discharge between uniform and filamentary by controlling pressures and pulse repetition frequencies

    Science.gov (United States)

    Yu, Sizhe; Lu, Xinpei

    2016-09-01

    We investigate the temporally resolved evolution of the nanosecond pulsed dielectric barrier discharge (DBD) in a moderate 6mm gap under various pressures and pulse repetition frequencies (PRFs) by intensified charge-coupled device (ICCD) images, using synthetic air and its components oxygen and nitrogen. It is found that the pressures are very different when the DBD mode transits between uniform and filamentary in air, oxygen, and nitrogen. The PRFs can also obviously affect the mode-transition. The transition mechanism in the pulsed DBD is not Townsend-to-streamer, which is dominant in the traditional alternating-voltage DBDs. The pulsed DBD in a uniform mode develops in the form of plane ionization wave, due to overlap of primary avalanches, while the increase in pressure disturbs the overlap and DBD develops in streamer instead, corresponding to the filamentary mode. Increasing the initiatory electron density by pre-ionization methods may contribute to discharge uniformity at higher pressures. We also find that the dependence of uniformity upon PRF is non-monotonic.

  7. HPGe detectors timing using pulse shape analysis techniques

    International Nuclear Information System (INIS)

    Crespi, F.C.L.; Vandone, V.; Brambilla, S.; Camera, F.; Million, B.; Riboldi, S.; Wieland, O.

    2010-01-01

    In this work the Pulse Shape Analysis has been used to improve the time resolution of High Purity Germanium (HPGe) detectors. A set of time aligned signals was acquired in a coincidence measurement using a coaxial HPGe and a cerium-doped lanthanum chloride (LaCl 3 :Ce) scintillation detector. The analysis using a Constant Fraction Discriminator (CFD) time output versus the HPGe signal shape shows that time resolution ranges from 2 to 12 ns depending on the slope in the initial part of the signal. An optimization procedure of the CFD parameters gives the same final time resolution (8 ns) as the one achieved after a correction of the CFD output based on the current pulse maximum position. Finally, an algorithm based on Pulse Shape Analysis was applied to the experimental data and a time resolution between 3 and 4 ns was obtained, corresponding to a 50% improvement as compared with that given by standard CFDs.

  8. Pulse shape analysis using CsI(Tl) Crystals

    International Nuclear Information System (INIS)

    Silva, J.; Fiori, E.; Loher, B.; Savran, D.; Wirth, R.; Vencelj, M.

    2013-06-01

    The decay time of CsI(Tl) scintillating material consists of more than a single exponential component. The ratio between the intensity of these components varies as a function of the ionizing power of the absorbed particles, such as γ -rays or protons, and the temperature. This property can therefore be used for particle discrimination and for temperature monitoring, using pulse shape analysis. An unsupervised method that uses fuzzy clustering algorithms for particle identification based on pulse shape analysis is presented. The method is applied to discriminate between photon and proton-induced signals in CsI(Tl) scintillator detectors. The first results of a method that uses pulse shape analysis for correcting the temperature-dependent gain effect of the detector are also presented. The method aims at conserving a good energy resolution in a temperature varying environment without the need to measure the temperature of the detector externally (authors)

  9. Magnetosphere and ionosphere response to a positive-negative pulse pair of solar wind dynamic pressure

    Science.gov (United States)

    Tian, A.; Degeling, A. W.

    2017-12-01

    Simulations and observations had shown that single positive/negative solar wind dynamic pressure pulse would excite geomagnetic impulsive events along with ionosphere and/or magnetosphere vortices which are connected by field aligned currents(FACs). In this work, a large scale ( 9min) magnetic hole event in solar wind provided us with the opportunity to study the effects of positive-negative pulse pair (△p/p 1) on the magnetosphere and ionosphere. During the magnetic hole event, two traveling convection vortices (TCVs, anti-sunward) first in anticlockwise then in clockwise rotation were detected by geomagnetic stations located along the 10:30MLT meridian. At the same time, another pair of ionospheric vortices azimuthally seen up to 3 MLT first in clockwise then in counter-clockwise rotation were also appeared in the afternoon sector( 14MLT) and centered at 75 MLAT without obvious tailward propagation feature. The duskside vortices were also confirmed in SuperDARN radar data. We simulated the process of magnetosphere struck by a positive-negative pulse pair and it shows that a pair of reversed flow vortices in the magnetosphere equatorial plane appeared which may provide FACs for the vortices observed in ionosphere. Dawn dusk asymmetry of the vortices as well as the global geomagnetism perturbation characteristics were also discussed.

  10. Regression analysis and transfer function in estimating the parameters of central pulse waves from brachial pulse wave.

    Science.gov (United States)

    Chai Rui; Li Si-Man; Xu Li-Sheng; Yao Yang; Hao Li-Ling

    2017-07-01

    This study mainly analyzed the parameters such as ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO) and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. These parameters extracted from the central pulse wave invasively measured were compared with the parameters measured from the brachial pulse waves by a regression model and a transfer function model. The accuracy of the parameters which were estimated by the regression model and the transfer function model was compared too. Our findings showed that in addition to the k value, the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation. Both the regression model parameters including A_slope, DBP, SEVR and the transfer function model parameters had good consistency with the parameters invasively measured, and they had the same effect of consistency. The regression equations of the three parameters were expressed by Y'=a+bx. The SBP, PP, SV, CO of central pulse wave could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

  11. The volume of the carotid bodies and blood pressure variability and pulse pressure in patients with essential hypertension

    International Nuclear Information System (INIS)

    Jaźwiec, P.; Gać, P.; Poręba, M.; Sobieszczańska, M.; Mazur, G.; Poręba, R.

    2016-01-01

    Aim: To assess the relationship between the volume of the carotid bodies (V rCB+lCB ) examined by means of computed tomography angiography (CTA) and blood pressure variability and pulse pressure (PP) in 24-hour ambulatory blood pressure monitoring (ABPM) in patients with essential hypertension. Materials and methods: A group of 52 patients with essential hypertension was examined (mean age: 68.32±12.31 years), the sizes of carotid bodies were measured by means of carotid artery CTA, and 24-hour ABPM was carried out. The 24-hour ABPM established systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), PP, SBP variability (SBPV), and DBP variability (DBPV). Results: SBP, MAP, and SBPV were significantly higher in the group of hypertension patients with V rCB+lCB equal to or above the median than in the group of hypertension patients with V rCB+lCB less than the median, as well as in the group of hypertension patients with oversized carotid bodies, than in the group of hypertension patients with normal V rCB+lCB . Moreover, the PP was statistically significantly higher in the group of hypertension patients with V rCB+lCB equal to or above the median than in the group of hypertension patients with V rCB+lCB less than the median. The existence of statistically significant positive linear relationships was revealed between V rCB+lCB and SBP, PP, and SBPV. A higher body mass index, older age, smoking, and higher V rCB+lCB are independent risk factors increasing SBPV in the research group. Conclusion: A positive relationship between the size of the carotid bodies and variability of the SBP and PP is observed in patients with essential hypertension. - Highlights: • Purpose. Determination of the relationships: V rCB+lCB vs. BPV and V rCB+lCB vs. PP. • Positive linear correlations were documented between V rCB+lCB and SBP, PP and SBPV. • Higher BMI, age, V rCB+lCB and smoking are independent risk factor of increased SBPV.

  12. Relations between diabetes, blood pressure and aortic pulse wave velocity in haemodialysis patients

    DEFF Research Database (Denmark)

    Peters, Christian Daugaard; Kjærgaard, Krista Dybtved; Dzeko, Mirela

    (HD) and 32 HD patients with DM (HD+DM). The SphygmoCor system was used for estimation of PWV. HD-duration, age, gender and BP medication were similar in the two groups. Mean DM-duration was 23±11 years and 25(78%) had type 2 DM. HD+DM had higher BMI (26±5 vs. 29±5 kg/m2, p=0.02), systolic BP (142......Diabetes (DM) is common in haemodialysis (HD) patients and affects both blood pressure (BP) and arterial stiffness. Carotid femoral pulse wave velocity (PWV) reflects the stiffness of the aorta and is regarded as a strong risk factor for cardiovascular (CV) mortality in HD patients. However, PWV......±20 vs. 152±21 mmHg, p=0.02) and pulse pressure (65±17 vs. 80±18 mmHg, p2.5 in HD and 12.3±3.1 m/s in HD+DM. The mean PWV difference HD vs. HD+DM was 3.1(1.9-4.3)m/s, p

  13. Impact of laser pulse duration on the reduction of intraocular pressure during selective laser trabeculoplasty.

    Science.gov (United States)

    Stunf Pukl, Spela; Drnovšek-Olup, Brigita

    2018-02-01

    To evaluate the efficacy of selective laser trabeculoplasty (SLT) to lower intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) or ocular hypertension (OHT), when performed with laser pulse duration of 1 ns compared with standard 3-5 ns. Bilateral SLT with a 532 nm Q-switched neodymium-doped yttrium aluminium garnet laser was conducted in 30 patients (60 eyes) with POAG (n = 5), NTG (n = 2) or OHT (n = 23). Pulse duration was 1 ns in the right eye (30 eyes; cases) and 3-5 ns in all left eyes (controls). Main outcome measures were IOP at 1 h, 1 day, 8 weeks and 6 months, and the rate of adverse ocular tissue reactions in all eyes. Mean 1 ns and 3-5 ns SLT IOPs were 24.1 and 24.3 mmHg, respectively, at baseline. No statistically significant difference in mean 1 ns and 3-5 ns SLT IOP was observed at 1 h (P = 0.761), 1 day (P = 0.758), 8 weeks (P = 0.352) and 6 months postoperatively (P = 0.879). No significant difference in postoperative anterior chamber inflammation was observed between the eyes (P = 0.529). Treatment with both laser pulse durations resulted in minor ultrastructural changes in the drainage angle. SLT performed with a 1 ns laser pulse duration does not appear to be inferior to SLT performed with the standard 3-5 ns duration at lowering IOP in treatment-naïve patients with POAG, NTG or OHT.

  14. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Directory of Open Access Journals (Sweden)

    Chin-Ming Huang

    2011-01-01

    Full Text Available This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP and heart rate variability (HRV. The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25±4 yr; 29 men and 31 women were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF and high-frequency (HF components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr (P<.05, but the cold stress significantly increased AIr (P<.01. The spectral energy of RPP did not show any statistical difference in 0∼10 Hz region under both conditions, but in the region of 10∼50 Hz, there was a significant increase (P<.01 in the heat test and a significant decrease in the cold test (P<.01. The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10∼50 Hz (SE10−50 Hz but not in the region of 0∼10 Hz (SE0−10 Hz. The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses.

  15. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Science.gov (United States)

    Huang, Chin-Ming; Chang, Hsien-Cheh; Kao, Shung-Te; Li, Tsai-Chung; Wei, Ching-Chuan; Chen, Chiachung; Liao, Yin-Tzu; Chen, Fun-Jou

    2011-01-01

    This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP) and heart rate variability (HRV). The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25 ± 4 yr; 29 men and 31 women) were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF) and high-frequency (HF) components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr) (P < .05), but the cold stress significantly increased AIr (P < .01). The spectral energy of RPP did not show any statistical difference in 0 ~ 10 Hz region under both conditions, but in the region of 10 ~ 50 Hz, there was a significant increase (P < .01) in the heat test and a significant decrease in the cold test (P < .01). The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10 ~ 50 Hz (SE10−50 Hz) but not in the region of 0 ~ 10 Hz (SE0−10 Hz). The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses. PMID:21113292

  16. Non-invasive measurements of pulse pressure variation and stroke volume variation in anesthetized patients using the Nexfin blood pressure monitor.

    Science.gov (United States)

    Stens, Jurre; Oeben, Jeroen; Van Dusseldorp, Ab A; Boer, Christa

    2016-10-01

    Nexfin beat-to-beat arterial blood pressure monitoring enables continuous assessment of hemodynamic indices like cardiac index (CI), pulse pressure variation (PPV) and stroke volume variation (SVV) in the perioperative setting. In this study we investigated whether Nexfin adequately reflects alterations in these hemodynamic parameters during a provoked fluid shift in anesthetized and mechanically ventilated patients. The study included 54 patients undergoing non-thoracic surgery with positive pressure mechanical ventilation. The provoked fluid shift comprised 15° Trendelenburg positioning, and fluid responsiveness was defined as a concomitant increase in stroke volume (SV) >10 %. Nexfin blood pressure measurements were performed during supine steady state, Trendelenburg and supine repositioning. Hemodynamic parameters included arterial blood pressure (MAP), CI, PPV and SVV. Trendelenburg positioning did not affect MAP or CI, but induced a decrease in PPV and SVV by 3.3 ± 2.8 and 3.4 ± 2.7 %, respectively. PPV and SVV returned back to baseline values after repositioning of the patient to baseline. Bland-Altman analysis of SVV and PPV showed a bias of -0.3 ± 3.0 % with limits of agreement ranging from -5.6 to 6.2 %. The SVV was more superior in predicting fluid responsiveness (AUC 0.728) than the PVV (AUC 0.636), respectively. The median bias between PPV and SVV was different for patients younger [-1.5 % (-3 to 0)] or older [+2 % (0-4.75)] than 55 years (P < 0.001), while there were no gender differences in the bias between PPV and SVV. The Nexfin monitor adequately reflects alterations in PPV and SVV during a provoked fluid shift, but the level of agreement between PPV and SVV was low. The SVV tended to be superior over PPV or Eadyn in predicting fluid responsiveness in our population.

  17. Flux transfer events at the dayside magnetopause: Transient reconnection or magnetosheath dynamic pressure pulses?

    International Nuclear Information System (INIS)

    Lockwood, M.

    1991-01-01

    The suggestion is discussed that characteristic particle and field signatures at the dayside magnetopause, termed flux transfer events, are, in at least some cases, due to transient solar wind and/or magnetosheath dynamic pressure increases, rather than time-dependent magnetic reconnection. It is found that most individual cases of FTEs observed by a single spacecraft can, at least qualitatively, be explained by the pressure pulse model, provided a few rather unsatisfactory features of the predictions are explained in terms of measurement uncertainties. The most notable exceptions to this are some two-regime observations made by two satellites simultaneously, one on either side of the magnetopause. However, this configuration has not been frequently achieved for sufficient time, such observations are rare, and the relevant tests are still not conclusive. The strongest evidence that FTEs are produced by magnetic reconnection is the dependence of their occurence on the north-south component of the interplanetary magnetic field (IMF) or of the magnetosheath field. The pressure pulse model provides an explanation for this dependence in the case of magnetosheath FTEs, but does not apply to magnetosphere FTEs. The only surveys of magnetosphere FTEs have not employed the simultaneous IMF, but have shown that their occurence is strongly dependent on the north-south component of the magnetosheath field, as observed earlier/later on the same magnetopause crossing. This paper employs statistics on the variability of the IMF orientation to investigate the effects of IMF changes between the times of the magnetosheath and FTE observations. It is shown that the previously published results are consistent with magnetospheric FTEs being entirely absent when the magentosheath field is northward

  18. Radial artery pulse waveform analysis based on curve fitting using discrete Fourier series.

    Science.gov (United States)

    Jiang, Zhixing; Zhang, David; Lu, Guangming

    2018-04-19

    Radial artery pulse diagnosis has been playing an important role in traditional Chinese medicine (TCM). For its non-invasion and convenience, the pulse diagnosis has great significance in diseases analysis of modern medicine. The practitioners sense the pulse waveforms in patients' wrist to make diagnoses based on their non-objective personal experience. With the researches of pulse acquisition platforms and computerized analysis methods, the objective study on pulse diagnosis can help the TCM to keep up with the development of modern medicine. In this paper, we propose a new method to extract feature from pulse waveform based on discrete Fourier series (DFS). It regards the waveform as one kind of signal that consists of a series of sub-components represented by sine and cosine (SC) signals with different frequencies and amplitudes. After the pulse signals are collected and preprocessed, we fit the average waveform for each sample using discrete Fourier series by least squares. The feature vector is comprised by the coefficients of discrete Fourier series function. Compared with the fitting method using Gaussian mixture function, the fitting errors of proposed method are smaller, which indicate that our method can represent the original signal better. The classification performance of proposed feature is superior to the other features extracted from waveform, liking auto-regression model and Gaussian mixture model. The coefficients of optimized DFS function, who is used to fit the arterial pressure waveforms, can obtain better performance in modeling the waveforms and holds more potential information for distinguishing different psychological states. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. A comparison between characteristics of atmospheric-pressure plasma jets sustained by nanosecond- and microsecond-pulse generators in helium

    International Nuclear Information System (INIS)

    Zhang, Cheng; Shao, Tao; Wang, Ruixue; Yan, Ping; Zhou, Zhongsheng; Zhou, Yixiao

    2014-01-01

    Power source is an important parameter that can affect the characteristics of atmospheric-pressure plasma jets (APPJs), because it can play a key role on the discharge characteristics and ionization process of APPJs. In this paper, the characteristics of helium APPJs sustained by both nanosecond-pulse and microsecond-pulse generators are compared from the aspects of plume length, discharge current, consumption power, energy, and optical emission spectrum. Experimental results showed that the pulsed APPJ was initiated near the high-voltage electrode with a small curvature radius, and then the stable helium APPJ could be observed when the applied voltage increased. Moreover, the discharge current of the nanosecond-pulse APPJ was larger than that of the microsecond-pulse APPJ. Furthermore, although the nanosecond-pulse generator consumed less energy than the microsecond-pulse generator, longer plume length, larger instantaneous power per pulse and stronger spectral line intensity could be obtained in the nanosecond-pulse excitation case. In addition, some discussion indicated that the rise time of the applied voltage could play a prominent role on the generation of APPJs

  20. Pulse shape analysis for γ-ray tracking. Part I: Pulse shape simulation with JASS

    International Nuclear Information System (INIS)

    Schlarb, M.; Gernhaeuser, R.; Klupp, S.; Kruecken, R.

    2011-01-01

    Next-generation γ -ray spectrometers based on highly segmented HPGe detectors are using the recent technique of γ -ray tracking to significantly improve on efficiency and Doppler correction capabilities. A precise reconstruction of the individual interaction locations within the active material is possible through the use of pulse shape analysis (PSA) which, in turn, demands an accurate knowledge of the detector response. We developed JASS, a Java-based simulation software package to generate pulse shapes for the AGATA detectors from physics constraints and basic material parameters. For verifying the simulation experimental data from a coincidence scan with known interaction locations was used. The achieved position resolution, in the order of a few millimeters, is within the requirements of the γ -ray tracking array. (orig.)

  1. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai , David ,; Lacoste , Deanna ,; Laux , C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  2. Study on the characteristics of barrier free surface discharge driven by repetitive nanosecond pulses at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Pang; Qiaogen, Zhang [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Kun, He [China Electric Power Research Institute, Beijing 100192 (China); Chunliang, Liu [State Key Laboratory for Physical Electronics and Devices, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-05-15

    Nanosecond pulsed plasma has an enormous potential in many applications. In this paper, the characteristics of barrier free nanosecond pulsed surface discharge are investigated by the use of an actuator with a strip-strip film electrode configuration, including the effect of electrode width and the gap distance on the plasma morphology and electrical characteristics at atmospheric pressure. It was found that it is relative easier to generate a quasi uniform discharge with a thinner electrode width and a smaller gap distance. The underlying physical mechanism was also discussed. Besides that, the influence of airflow on repetitive pulsed surface discharge was examined. By comparing to the discharge produced by two different pulse waveforms in airflows, we found that the discharge driven by a faster pulse behaves more stable. Finally, a model was developed to analyze the interaction of the airflow and the discharge channels.

  3. Investigation on the generation characteristic of pressure pulse wave signal during the measurement-while-drilling process

    Science.gov (United States)

    Changqing, Zhao; Kai, Liu; Tong, Zhao; Takei, Masahiro; Weian, Ren

    2014-04-01

    The mud-pulse logging instrument is an advanced measurement-while-drilling (MWD) tool and widely used by the industry in the world. In order to improve the signal transmission rate, ensure the accurate transmission of information and address the issue of the weak signal on the ground of oil and gas wells, the signal generator should send out the strong mud-pulse signals with the maximum amplitude. With the rotary valve pulse generator as the study object, the three-dimensional Reynolds NS equations and standard k - ɛ turbulent model were used as a mathematical model. The speed and pressure coupling calculation was done by simple algorithms to get the amplitudes of different rates of flow and axial clearances. Tests were done to verify the characteristics of the pressure signals. The pressure signal was captured by the standpiece pressure monitoring system. The study showed that the axial clearances grew bigger as the pressure wave amplitude value decreased and caused the weakening of the pulse signal. As the rate of flow got larger, the pressure wave amplitude would increase and the signal would be enhanced.

  4. Modeling seismic stimulation: Enhanced non-aqueous fluid extraction from saturated porous media under pore-pressure pulsing at low frequencies

    Science.gov (United States)

    Lo, Wei-Cheng; Sposito, Garrison; Huang, Yu-Han

    2012-03-01

    Seismic stimulation, the application of low-frequency stress-pulsing to the boundary of a porous medium containing water and a non-aqueous fluid to enhance the removal of the latter, shows great promise for both contaminated groundwater remediation and enhanced oil recovery, but theory to elucidate the underlying mechanisms lag significantly behind the progress achieved in experimental research. We address this conceptual lacuna by formulating a boundary-value problem to describe pore-pressure pulsing at seismic frequencies that is based on the continuum theory of poroelasticity for an elastic porous medium permeated by two immiscible fluids. An exact analytical solution is presented that is applied numerically using elasticity parameters and hydraulic data relevant to recent proof-of-principle laboratory experiments investigating the stimulation-induced mobilization of trichloroethene (TCE) in water flowing through a compressed sand core. The numerical results indicated that significant stimulation-induced increases of the TCE concentration in effluent can be expected from pore-pressure pulsing in the frequency range of 25-100 Hz, which is in good agreement with what was observed in the laboratory experiments. Sensitivity analysis of our numerical results revealed that the TCE concentration in the effluent increases with the porous medium framework compressibility and the pulsing pressure. Increasing compressibility also leads to an optimal stimulation response at lower frequencies, whereas changing the pulsing pressure does not affect the optimal stimulation frequency. Within the context of our model, the dominant physical cause for enhancement of non-aqueous fluid mobility by seismic stimulation is the dilatory motion of the porous medium in which the solid and fluid phases undergo opposite displacements, resulting in stress-induced changes of the pore volume.

  5. Predictive value of pulse pressure variation for fluid responsiveness in septic patients using lung-protective ventilation strategies.

    Science.gov (United States)

    Freitas, F G R; Bafi, A T; Nascente, A P M; Assunção, M; Mazza, B; Azevedo, L C P; Machado, F R

    2013-03-01

    The applicability of pulse pressure variation (ΔPP) to predict fluid responsiveness using lung-protective ventilation strategies is uncertain in clinical practice. We designed this study to evaluate the accuracy of this parameter in predicting the fluid responsiveness of septic patients ventilated with low tidal volumes (TV) (6 ml kg(-1)). Forty patients after the resuscitation phase of severe sepsis and septic shock who were mechanically ventilated with 6 ml kg(-1) were included. The ΔPP was obtained automatically at baseline and after a standardized fluid challenge (7 ml kg(-1)). Patients whose cardiac output increased by more than 15% were considered fluid responders. The predictive values of ΔPP and static variables [right atrial pressure (RAP) and pulmonary artery occlusion pressure (PAOP)] were evaluated through a receiver operating characteristic (ROC) curve analysis. Thirty-four patients had characteristics consistent with acute lung injury or acute respiratory distress syndrome and were ventilated with high levels of PEEP [median (inter-quartile range) 10.0 (10.0-13.5)]. Nineteen patients were considered fluid responders. The RAP and PAOP significantly increased, and ΔPP significantly decreased after volume expansion. The ΔPP performance [ROC curve area: 0.91 (0.82-1.0)] was better than that of the RAP [ROC curve area: 0.73 (0.59-0.90)] and pulmonary artery occlusion pressure [ROC curve area: 0.58 (0.40-0.76)]. The ROC curve analysis revealed that the best cut-off for ΔPP was 6.5%, with a sensitivity of 0.89, specificity of 0.90, positive predictive value of 0.89, and negative predictive value of 0.90. Automatized ΔPP accurately predicted fluid responsiveness in septic patients ventilated with low TV.

  6. Impact of Mental and Physical Stress on Blood Pressure and Pulse Pressure under Normobaric versus Hypoxic Conditions

    Science.gov (United States)

    Trapp, Michael; Trapp, Eva-Maria; Egger, Josef W.; Domej, Wolfgang; Schillaci, Giuseppe; Avian, Alexander; Rohrer, Peter M.; Hörlesberger, Nina; Magometschnigg, Dieter; Cervar-Zivkovic, Mila; Komericki, Peter; Velik, Rosemarie; Baulmann, Johannes

    2014-01-01

    Objective Hypobaric hypoxia, physical and psychosocial stress may influence key cardiovascular parameters including blood pressure (BP) and pulse pressure (PP). We investigated the effects of mild hypobaric hypoxia exposure on BP and PP reactivity to mental and physical stress and to passive elevation by cable car. Methods 36 healthy volunteers participated in a defined test procedure consisting of a period of rest 1, mental stress task (KLT-R), period of rest 2, combined mental (KLT-R) and physical task (bicycle ergometry) and a last period of rest both at Graz, Austria (353 m asl) and at the top station Dachstein (2700 m asl). Beat-to-beat heart rate and BP were analysed both during the test procedures at Graz and at Dachstein and during passive 1000 m elevation by cable car (from 1702 m to 2700 m). Results A significant interaction of kind of stress (mental vs. combined mental and physical) and study location (Graz vs. Dachstein) was found in the systolic BP (p = .007) and PP (p = .002) changes indicating that during the combined mental and physical stress task sBP was significantly higher under hypoxic conditions whereas sBP and PP were similar during mental stress both under normobaric normoxia (Graz) and under hypobaric hypoxia (Dachstein). During the passive ascent in cable car less trivialization (psychological coping strategy) was associated with an increase in PP (p = .004). Conclusion Our data show that combined mental and physical stress causes a significant higher raise in sBP and PP under hypoxic conditions whereas isolated mental stress did not affect sBP and PP under hypoxic conditions. PP-reaction to ascent in healthy subjects is not uniform. BP reactions to ascent that represents an accumulation of physical (mild hypobaric hypoxia) and psychological stressors depend on predetermined psychological traits (stress coping strategies). Thus divergent cardiovascular reactions can be explained by applying the multidimensional aspects of the

  7. Impact of mental and physical stress on blood pressure and pulse pressure under normobaric versus hypoxic conditions.

    Directory of Open Access Journals (Sweden)

    Michael Trapp

    Full Text Available Hypobaric hypoxia, physical and psychosocial stress may influence key cardiovascular parameters including blood pressure (BP and pulse pressure (PP. We investigated the effects of mild hypobaric hypoxia exposure on BP and PP reactivity to mental and physical stress and to passive elevation by cable car.36 healthy volunteers participated in a defined test procedure consisting of a period of rest 1, mental stress task (KLT-R, period of rest 2, combined mental (KLT-R and physical task (bicycle ergometry and a last period of rest both at Graz, Austria (353 m asl and at the top station Dachstein (2700 m asl. Beat-to-beat heart rate and BP were analysed both during the test procedures at Graz and at Dachstein and during passive 1000 m elevation by cable car (from 1702 m to 2700 m.A significant interaction of kind of stress (mental vs. combined mental and physical and study location (Graz vs. Dachstein was found in the systolic BP (p = .007 and PP (p = .002 changes indicating that during the combined mental and physical stress task sBP was significantly higher under hypoxic conditions whereas sBP and PP were similar during mental stress both under normobaric normoxia (Graz and under hypobaric hypoxia (Dachstein. During the passive ascent in cable car less trivialization (psychological coping strategy was associated with an increase in PP (p = .004.Our data show that combined mental and physical stress causes a significant higher raise in sBP and PP under hypoxic conditions whereas isolated mental stress did not affect sBP and PP under hypoxic conditions. PP-reaction to ascent in healthy subjects is not uniform. BP reactions to ascent that represents an accumulation of physical (mild hypobaric hypoxia and psychological stressors depend on predetermined psychological traits (stress coping strategies. Thus divergent cardiovascular reactions can be explained by applying the multidimensional aspects of the biopsychosocial concept.

  8. Pulse wave analysis in a 180-degree curved artery model: Implications under physiological and non-physiological inflows

    Science.gov (United States)

    Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    Systolic and diastolic blood pressures, pulse pressures, and left ventricular hypertrophy contribute to cardiovascular risks. Increase of arterial stiffness due to aging and hypertension is an important factor in cardiovascular, chronic kidney and end-stage-renal-diseases. Pulse wave analysis (PWA) based on arterial pressure wave characteristics, is well established in clinical practice for evaluation of arterial distensibility and hypertension. The objective of our exploratory study in a rigid 180-degree curved artery model was to evaluate arterial pressure waveforms. Bend upstream conditions were measured using a two-component, two-dimensional, particle image velocimeter (2C-2D PIV). An ultrasonic transit-time flow meter and a catheter with a MEMS-based solid state pressure sensor, capable of measuring up to 20 harmonics of the observed pressure waveform, monitored flow conditions downstream of the bend. Our novel continuous wavelet transform algorithm (PIVlet 1.2), in addition to detecting coherent secondary flow structures is used to evaluate arterial pulse wave characteristics subjected to physiological and non-physiological inflows. Results of this study will elucidate the utility of wavelet transforms in arterial function evaluation and pulse wave speed. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  9. Determination of pseudo multi-pulse production rate in GM counters by correlation analysis between signal pulses

    International Nuclear Information System (INIS)

    Hashimoto, Kengo; Ueda, Taizou

    1996-01-01

    A technique, based on the correlation analysis of signal pulses in time sequence, is proposed to determine the production rate of the pseudo multi-pulse in Geiger-Mueller (GM) counter. With a multi-channel scaler initiated by a signal pulse, subsequent pulses are recorded in sequence. The production of the multi-pulse increases the counting probability immediately after the initiation. By examining the deviation of the measured probability from the ideal counting probability, the production rate and the average lag time to produce the multi-pulse can be determined. By the use of the present technique, the production rate and the average lag time were obtained for the various GM tubes. These results indicate that the consumption of the quench gas results in a significant increase in the production rate but little variation in the lag time, and that the lag time strongly depends on the tube diameter. (author)

  10. Comparing the Effect of Labetalol versus Morphine on Controlling Blood Pressure and Pulse Rate During Emergence from Anesthesia after Craniotomy

    Directory of Open Access Journals (Sweden)

    Mohammadali Attari

    2017-01-01

    Full Text Available Background: Emergence from anesthesia is associated with sympathetic stimulation, increase in pulse and blood pressure. There are different methods, but the most appropriate method should be selected regarding the differences in nationalities. This study aimed to compare the efficacy of morphine and labetalol in controlling blood pressure and pulse during emergence from anesthesia in brain tumors craniotomy. Materials and Methods: This study was conducted at Al-Zahra Hospital of Isfahan - Iran on 60 patients suffering from brain tumor candidated for craniotomy and randomly classified into two groups of 30. One group received labetalol with dose of 10 mg over 10 min from 45 min before finishing dressing and then 0.75 mg/min until 35 min later; another group received morphine in bolus dose of 0.1 mg/kg during 2–3 min. Blood pressure and pulse were measured every 10 min over 40 min. After operation, they were measured every 5 min over 15 min. Results: The morphine group had higher systolic (133.3 ± 18.8 and diastolic blood pressure (87.1 ± 13.6 (P = 0.021 and 0.028, respectively at extubation and during 45 min before dressing, the diastolic blood pressure was significantly higher in compares with labetalol (75.3 ± 10.5 (P < 0.05. And extubation time was significantly shorter in labetalol group (7.7 ± 0.84 (P < 0.001. Pulse had no significant difference in both groups. In labetalol group, blood pressure and pulse fluctuations were more stable. Conclusion: Administration of labetalol 45 min before finishing dressing can significantly control blood pressure during emergence from anesthesia and also shorten the time of extubation during emergence in patients undergoing craniotomy.

  11. Experimental study on vapor explosion induced by pressure pulse in coarse mixing of hot molten metal and water

    International Nuclear Information System (INIS)

    Inoue, A.; Tobita, Y.; Aritomi, M.; Takahashi, M.; Matsuzaki, M.

    2004-01-01

    An experimental study was done to investigate characteristics of metal-water interaction, when a mount of hot liquid metal is injected into the water. The test section is a vertical shock tube of 60mm in inner diameter and 1200mm in length. A special injector which is designed to inject hot metal of controlled volume and flow rate is attached at the top of the tube. When the hot metal is injected in the water and comes down at a position of the test vessel, a trigger pressure pulse is generated at the bottom of the test tube. Local transient pressures along the tube are measured by piezo pressure transducers. The following items were investigated in the experiment; 1) The criteria to cause a vapor explosion, 2) Transient behaviors and propagation characteristics of pressure wave in the mixing region. 3) Effects of triggering pulse, injection temperature and mass of hot molten metal on the peak pressure. The probability of the vapor explosion jumped when the interface temperature at the molten metal-water direct contact is higher than the homogeneous nucleation temperature of water and the triggering pulse becomes larger than 0.9MPa. Two types of the pressure propagation modes are observed, one is the detonative mode with a sharp rise and other is usual pressure mode with a mild rise. (author)

  12. Simultaneous multi-element analysis of some edible pulses using neutron activation analysis

    International Nuclear Information System (INIS)

    El-Sweify, F.H.; Metwally, E.; Abdel-Khalik, H.

    2007-01-01

    This paper comprises the application of instrumental neutron activation analysis (INAA) for multi-element determination in some edible pulse samples. These edible pulses are usually daily used in the Egyptian kitchen. These were: anise, cumin, coriander, caraway, black cumin, white kidney bean, lupine, lentil, chickpea, broad bean, peanut, almond, and fenugreek. The pulses have been analyzed as dehulled pulses, in the case of legume and oil pulses with simultaneous analysis of their respective skins. The determined elements were: Ce, Co, Cr, Cs, Eu, Fe, Hf, Rb, Sb, Sc, Sr, Th and Zn. The element content in the dehulled pulses and their respective skins has been compared. Some elements were major or minor elements where others were trace elements. Standard reference materials were used to assure quality control, accuracy and precision of the technique. (author)

  13. Using an expiratory resistor, arterial pulse pressure variations predict fluid responsiveness during spontaneous breathing: an experimental porcine study.

    Science.gov (United States)

    Dahl, Michael K; Vistisen, Simon T; Koefoed-Nielsen, Jacob; Larsson, Anders

    2009-01-01

    Fluid responsiveness prediction is difficult in spontaneously breathing patients. Because the swings in intrathoracic pressure are minor during spontaneous breathing, dynamic parameters like pulse pressure variation (PPV) and systolic pressure variation (SPV) are usually small. We hypothesized that during spontaneous breathing, inspiratory and/or expiratory resistors could induce high arterial pressure variations at hypovolemia and low variations at normovolemia and hypervolemia. Furthermore, we hypothesized that SPV and PPV could predict fluid responsiveness under these conditions. Eight prone, anesthetized and spontaneously breathing pigs (20 to 25 kg) were subjected to a sequence of 30% hypovolemia, normovolemia, and 20% and 40% hypervolemia. At each volemic level, the pigs breathed in a randomized order either through an inspiratory and/or an expiratory threshold resistor (7.5 cmH2O) or only through the tracheal tube without any resistor. Hemodynamic and respiratory variables were measured during the breathing modes. Fluid responsiveness was defined as a 15% increase in stroke volume (DeltaSV) following fluid loading. Stroke volume was significantly lower at hypovolemia compared with normovolemia, but no differences were found between normovolemia and 20% or 40% hypervolemia. Compared with breathing through no resistor, SPV was magnified by all resistors at hypovolemia whereas there were no changes at normovolemia and hypervolemia. PPV was magnified by the inspiratory resistor and the combined inspiratory and expiratory resistor. Regression analysis of SPV or PPV versus DeltaSV showed the highest R2 (0.83 for SPV and 0.52 for PPV) when the expiratory resistor was applied. The corresponding sensitivity and specificity for prediction of fluid responsiveness were 100% and 100%, respectively, for SPV and 100% and 81%, respectively, for PPV. Inspiratory and/or expiratory threshold resistors magnified SPV and PPV in spontaneously breathing pigs during hypovolemia

  14. Can the use of pulsed direct current induce oscillation in the applied pressure during spark plasma sintering?

    International Nuclear Information System (INIS)

    Salamon, David; Eriksson, Mirva; Nygren, Mats; Shen Zhijian

    2012-01-01

    The spark plasma sintering (SPS) process is known for its rapid densification of metals and ceramics. The mechanism behind this rapid densification has been discussed during the last few decades and is yet uncertain. During our SPS experiments we noticed oscillations in the applied pressure, related to a change in electric current. In this study, we investigated the effect of pulsed electrical current on the applied mechanical pressure and related changes in temperature. We eliminated the effect of sample shrinkage in the SPS setup and used a transparent quartz die allowing direct observation of the sample. We found that the use of pulsed direct electric current in our apparatus induces pressure oscillations with the amplitude depending on the current density. While sintering Ti samples we observed temperature oscillations resulting from pressure oscillations, which we attribute to magnetic forces generated within the SPS apparatus. The described current–pressure–temperature relations might increase understanding of the SPS process.

  15. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    International Nuclear Information System (INIS)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi; Xie, Yanqiong; Xu, Xiaojun

    2015-01-01

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector

  16. Patient-ventilator asynchrony affects pulse pressure variation prediction of fluid responsiveness.

    Science.gov (United States)

    Messina, Antonio; Colombo, Davide; Cammarota, Gianmaria; De Lucia, Marta; Cecconi, Maurizio; Antonelli, Massimo; Corte, Francesco Della; Navalesi, Paolo

    2015-10-01

    During partial ventilatory support, pulse pressure variation (PPV) fails to adequately predict fluid responsiveness. This prospective study aims to investigate whether patient-ventilator asynchrony affects PPV prediction of fluid responsiveness during pressure support ventilation (PSV). This is an observational physiological study evaluating the response to a 500-mL fluid challenge in 54 patients receiving PSV, 27 without (Synch) and 27 with asynchronies (Asynch), as assessed by visual inspection of ventilator waveforms by 2 skilled blinded physicians. The area under the curve was 0.71 (confidence interval, 0.57-0.83) for the overall population, 0.86 (confidence interval, 0.68-0.96) in the Synch group, and 0.53 (confidence interval, 0.33-0.73) in the Asynch group (P = .018). Sensitivity and specificity of PPV were 78% and 89% in the Synch group and 36% and 46% in the Asynch group. Logistic regression showed that the PPV prediction was influenced by patient-ventilator asynchrony (odds ratio, 8.8 [2.0-38.0]; P < .003). Of the 27 patients without asynchronies, 12 had a tidal volume greater than or equal to 8 mL/kg; in this subgroup, the rate of correct classification was 100%. Patient-ventilator asynchrony affects PPV performance during partial ventilatory support influencing its efficacy in predicting fluid responsiveness. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Pingbing; Feng, Xueshang; Wang, Yi [SIGMA Weather Group, State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Xie, Yanqiong [College of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing (China); Xu, Xiaojun, E-mail: pbzuo@spaceweather.ac.cn, E-mail: fengx@spaceweather.ac.cn [Space Science Institute, Macau University of Science and Technology, Macao (China)

    2015-10-20

    In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.

  18. Association of Pulse Pressure with Serum TNF-α and Neutrophil Count in the Elderly

    Directory of Open Access Journals (Sweden)

    Eriko Yamada

    2014-01-01

    Full Text Available Aims. Elevated pulse pressure (PP has been reported to be a risk factor for type 2 diabetes in elderly patients with hypertension. Methods. Cross-sectional relationships of PP with known risk factors for type 2 diabetes and inflammatory markers were examined in 150 elderly community-dwelling women, 79 women (52.7% of whom had hypertension. Results. Systolic blood pressure (standardized β, 0.775, log tumor necrosis factor-α (TNF-α, standardized β, 0.110, age (standardized β, 0.140, and neutrophil count (standardized β, 0.114 emerged as determinants of PP independent of high-sensitivity C-reactive protein, interleukin-6, monocyte count, plasminogen activator inhibitor-1, homeostasis model assessment of insulin resistance, HDL-cholesterol, and adiponectin (R2 = 0.772. Conclusions. The present studies have demonstrated an independent association of higher PP with higher TNF-α, a marker of insulin resistance, and neutrophil count in community-living elderly women and suggest that insulin resistance and chronic low-grade inflammation may in part be responsible for the association between high PP and incident type 2 diabetes found in elderly patients with hypertension.

  19. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure

    Science.gov (United States)

    Roth, Caleb C.; Barnes Jr., Ronald A.; Ibey, Bennett L.; Beier, Hope T.; Christopher Mimun, L.; Maswadi, Saher M.; Shadaram, Mehdi; Glickman, Randolph D.

    2015-01-01

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, electrochemical interactions, thermoelastic expansion, and others. To date, very limited research has investigated non-electric phenomena occurring during nsEP exposures and their potential effect on cell nanoporation. Of primary interest is the production of acoustic shock waves during nsEP exposure, as it is known that acoustic shock waves can cause membrane poration (sonoporation). Based on these observations, our group characterized the acoustic pressure transients generated by nsEP and determined if such transients played any role in nanoporation. In this paper, we show that nsEP exposures, equivalent to those used in cellular studies, are capable of generating high-frequency (2.5 MHz), high-intensity (>13 kPa) pressure transients. Using confocal microscopy to measure cell uptake of YO-PRO®-1 (indicator of nanoporation of the plasma membrane) and changing the electrode geometry, we determined that acoustic waves alone are not responsible for poration of the membrane. PMID:26450165

  20. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure.

    Science.gov (United States)

    Roth, Caleb C; Barnes, Ronald A; Ibey, Bennett L; Beier, Hope T; Christopher Mimun, L; Maswadi, Saher M; Shadaram, Mehdi; Glickman, Randolph D

    2015-10-09

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, electrochemical interactions, thermoelastic expansion, and others. To date, very limited research has investigated non-electric phenomena occurring during nsEP exposures and their potential effect on cell nanoporation. Of primary interest is the production of acoustic shock waves during nsEP exposure, as it is known that acoustic shock waves can cause membrane poration (sonoporation). Based on these observations, our group characterized the acoustic pressure transients generated by nsEP and determined if such transients played any role in nanoporation. In this paper, we show that nsEP exposures, equivalent to those used in cellular studies, are capable of generating high-frequency (2.5 MHz), high-intensity (>13 kPa) pressure transients. Using confocal microscopy to measure cell uptake of YO-PRO®-1 (indicator of nanoporation of the plasma membrane) and changing the electrode geometry, we determined that acoustic waves alone are not responsible for poration of the membrane.

  1. An in vitro quantification of pressures exerted by earlobe pulse oximeter probes following reports of device-related pressure ulcers in ICU patients .

    Science.gov (United States)

    Goodell, Teresa T

    2012-11-01

    The earlobe often is used to monitor perfusion when pulse oximeter signal quality is impaired in the fingers and toes. Prompted by intermittent occurrences of roughly circular earlobe pressure ulcers among patients in intensive care units, a convenience sample of seven calibrated pulse oximeter probes was used to quantify earlobe pressure exerted by these devices in vitro. All were tested twice with an electronic load cell, a strain gauge with a transducer that transforms the measured force into a readable numerical signal. The probe was clipped to the load cell just as it is clipped to the earlobe in the clinical setting. The probes exerted an average of 0.24 lb (SD 0.6) of force over an area of 0.3 square inches, equal to an average of 20.7 mm Hg (SD 0.6) pressure on tissue. This value exceeds some empirically derived values of capillary perfusion pressure. The occurrence of device-related pressure ulcers, as well pressure ulcers on the ears, has been documented, but little is known about device-related earlobe pressure ulcers or the actual pressure exerted by these devices. Additional in vitro studies are needed to quantify the pressures exerted by these and other probes, and future prevalence and incidence studies should include more detailed pressure ulcer location and device use documentation. Until more is known about the possible role of these devices in the development of pressure ulcers, clinicians should be cognizant of their potential for causing pressure ulcers, particularly in patients whose conditions can compromise skin integrity.

  2. High pressure pulsed avalanche discharges: Scaling of required preionization rate for homogeneity

    International Nuclear Information System (INIS)

    Brenning, N.; Axnaes, I.; Nilsson, J.O.; Eninger, J.E.

    1994-01-01

    Homogeneous high-pressure discharges can be formed by pulsed avalanche breakdown, provided that the individual avalanche heads have diffused to a large enough radius to overlap before streamer breakdown occurs. The overlap condition can be met by using an external mechanism to preionize the neutral gas, e.g., x-rays or uv radiation. There are several scenarios, (1) to preionize the gas, and then trigger the discharge by the sudden application of an electric field, (2) to apply an overvoltage over the discharge and trigger the discharge by external ionization, or (3) to have a continuous rate of external ionization and let the E field rise, with a comparatively long time constant τ, across the breakdown value (E/n) 0 . The authors here study the last of these scenarios, which gives a very efficient use of the preionization source because the avalanche startpoint can accumulate during the pre-avalanche phase. The authors have found that the required avalanche startpoint density N st.p , defined as the density of individual single, or clusters of, electrons at the time when the electric field crosses the breakdown value, scales with pressure and rise time as N st.p ∝ p 21/4 τ -3/4 . This pressure scaling disagrees with the p 3/2 scaling found by Levatter and Lin (J. Appl. Phys. 51(1), 210), while the rise time scaling agrees satisfactorily with their results. For an E field which rises slowly across the breakdown value, the pre-avalanche accumulation of electrons must be taken into account, as well as the fact that the density n e of free electrons becomes larger than the density N st.p of independent avalanche heads: when electron impact ionization closely balances attachment, individual electrons are replaced by clusters of electrons which are too close to form individual avalanche heads

  3. Stability analysis of ELMs in long-pulse discharges with ELITE code on EAST tokamak

    Science.gov (United States)

    Wang, Y. F.; Xu, G. S.; Wan, B. N.; Li, G. Q.; Yan, N.; Li, Y. L.; Wang, H. Q.; Peng, Y.-K. Martin; Xia, T. Y.; Ding, S. Y.; Chen, R.; Yang, Q. Q.; Liu, H. Q.; Zang, Q.; Zhang, T.; Lyu, B.; Xu, J. C.; Feng, W.; Wang, L.; Chen, Y. J.; Luo, Z. P.; Hu, G. H.; Zhang, W.; Shao, L. M.; Ye, Y.; Lan, H.; Chen, L.; Li, J.; Zhao, N.; Wang, Q.; Snyder, P. B.; Liang, Y.; Qian, J. P.; Gong, X. Z.; EAST team

    2018-05-01

    One challenge in long-pulse and high performance tokamak operation is to control the edge localized modes (ELMs) to reduce the transient heat load on plasma facing components. Minute-scale discharges in H-mode have been achieved repeatedly on Experimental Advanced Superconducting Tokamak (EAST) since the 2016 campaign and understanding the characteristics of the ELMs in these discharges can be helpful for effective ELM control in long-pulse discharges. The kinetic profile diagnostics recently developed on EAST make it possible to perform the pedestal stability analysis quantitatively. Pedestal stability calculation of a typical long-pulse discharge with ELITE code is presented. The ideal linear stability results show that the ELM is dominated by toroidal mode number n around 10–15 and the most unstable mode structure is mainly localized in the steep pressure gradient region, which is consistent with experimental results. Compared with a typical type-I ELM discharge with larger total plasma current (I p = 600 kA), pedestal in the long-pulse H-mode discharge (I p = 450 kA) is more stable in peeling-ballooning instability and its critical peak pressure gradient is evaluated to be 65% of the former. Two important features of EAST tokamak in the long-pulse discharge are presented by comparison with other tokamaks, including a wider pedestal correlated with the poloidal pedestal beta and a smaller inverse aspect ratio and their effects on the pedestal stability are discussed. The effects of uncertainties in measurements on the linear stability results are also analyzed, including the edge electron density profile position, the separatrix position and the line-averaged effective ion charge {Z}{{e}{{f}}{{f}}} value.

  4. Numerical simulation of atmospheric-pressure helium discharge driven by combined radio frequency and trapezoidal pulse sources

    International Nuclear Information System (INIS)

    Wang Qi; Sun Jizhong; Zhang Jianhong; Ding Zhenfeng; Wang Dezhen

    2010-01-01

    Atmospheric-pressure capacitive discharges driven by combined radio frequency (rf) and trapezoidal pulse sources are investigated using a one-dimensional self-consistent fluid model. The results show that the plasma intensity in the rf discharge can be enhanced drastically when a low duty ratio short pulse source is additionally applied. The mechanism for the increase in the plasma density can be attributed to a strong localized electric field induced by the applied short pulse; the strong electric field generates a great number of high energy electrons and chemically active particles, which subsequently generate more electrons and ions. The rf capacitive discharges with the aid of externally applied short pulses can achieve a high plasma density with better power efficiency.

  5. Production of atmospheric pressure diffuse nanosecond pulsed dielectric barrier discharge using the array needles-plate electrode in air

    International Nuclear Information System (INIS)

    Yang Dezheng; Wang Wenchun; Jia Li; Nie Dongxia; Shi Hengchao

    2011-01-01

    In this paper, a bidirectional high pulse voltage with 20 ns rising time is employed to generate an atmospheric pressure diffuse dielectric barrier discharge using the array needles-plate electrode configuration. Both double needle and multiple needle electrode configurations nanosecond pulsed dielectric barrier discharges are investigated. It is found that a diffuse discharge plasma with low gas temperature can be obtained, and the plasma volume increases with the increase of the pulse peak voltage, but remains almost constant with the increase of the pulse repetition rate. In addition to showing the potential application on a topographically nonuniform surface treatment of the discharge, the multiple needle-plate electrode configuration with different needle-plate electrode gaps are also employed to generate diffuse discharge plasma.

  6. Transition between trickle flow and pulse flow in a cocurrent gas-liquid trickle-bed reactor at elevated pressures

    NARCIS (Netherlands)

    Wammes, W.J.A.; Mechielsen, S.J.; Westerterp, K.R.

    1992-01-01

    The effect of reactor pressure in the range of 0.2–2.0 MPa on the transition between the trickle-flow and the pulse-flow regime has been investigated for the non-foaming water—nitrogen and aqueous 40% ethyleneglycol—nitrogen systems. Most models and flow charts which are all based on atmospheric

  7. NO kinetics in pulsed low-pressure nitrogen plasmas studied by time resolved quantum cascade laser absorption spectroscopy

    NARCIS (Netherlands)

    Welzel, S.; Guaitella, O.; Lazzaroni, C.; Pintassilgo, C.; Rousseau, A.; Röpcke, J.

    2011-01-01

    Time-resolved quantum cascade laser absorption spectroscopy at 1897 cm-1 (5.27 µm) has been applied to study the NO(X) kinetics on the micro- and millisecond time scale in pulsed low-pressure N2/NO dc discharges. Experiments have been performed under flowing and static gas conditions to infer the

  8. Determination of etching parameters for pulsed XeF2 etching of silicon using chamber pressure data

    Science.gov (United States)

    Sarkar, Dipta; Baboly, M. G.; Elahi, M. M.; Abbas, K.; Butner, J.; Piñon, D.; Ward, T. L.; Hieber, Tyler; Schuberth, Austin; Leseman, Z. C.

    2018-04-01

    A technique is presented for determination of the depletion of the etchant, etched depth, and instantaneous etch rate for Si etching with XeF2 in a pulsed etching system in real time. The only experimental data required is the pressure data collected temporally. Coupling the pressure data with the knowledge of the chemical reactions allows for the determination of the etching parameters of interest. Using this technique, it is revealed that pulsed etching processes are nonlinear, with the initial etch rate being the highest and monotonically decreasing as the etchant is depleted. With the pulsed etching system introduced in this paper, the highest instantaneous etch rate of silicon was recorded to be 19.5 µm min-1 for an initial pressure of 1.2 Torr for XeF2. Additionally, the same data is used to determine the rate constant for the reaction of XeF2 with Si; the reaction is determined to be second order in nature. The effect of varying the exposed surface area of Si as well as the effect that pressure has on the instantaneous etch rate as a function of time is shown applying the same technique. As a proof of concept, an AlN resonator is released using XeF2 pulses to remove a sacrificial poly-Si layer.

  9. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...

  10. Noninvasive pulse pressure variation and stroke volume variation to predict fluid responsiveness at multiple thresholds : a prospective observational study

    NARCIS (Netherlands)

    Vos, Jaap Jan; Poterman, Marieke; Papineau Salm, Pieternel; Van Amsterdam, Kai; Struys, Michel M. R. F.; Scheeren, Thomas W. L.; Kalmar, Alain F.

    2015-01-01

    Pulse pressure variation (PPV) and stroke volume variation (SVV) are dynamic preload variables that can be measured noninvasively to assess fluid responsiveness (FR) in anesthetized patients with mechanical ventilation. Few studies have examined the effectiveness of predicting FR according to the

  11. Detailed Analysis of ECMWF Surface Pressure Data

    Science.gov (United States)

    Fagiolini, E.; Schmidt, T.; Schwarz, G.; Zenner, L.

    2012-04-01

    Investigations of temporal variations within the gravity field of the Earth led us to the analysis of common surface pressure data products delivered by ECMWF. We looked into the characteristics of global as well as spatially and temporally confined phenomena being visible in the data. In particular, we were interested in the overall data quality, the local and temporal signal-to-noise ratio of surface pressure data sets, and the identification of irregular data. To this end, we analyzed a time series of a full year of surface pressure operational analysis data and their nominal standard deviations. The use of pressure data on a Gaussian grid data allowed us to remain close to the internal computations at ECMWF during data assimilation. Thus, we circumvented potential interpolation effects that would otherwise occur in cylindrical projections of conventional map products. The results obtained by us demonstrate the identification of a few distinct outliers, data quality effects over land or water and along coastlines as well as neighborhood effects of samples within and outside of the tropics. Small scale neighborhood effects depend on their geographical direction, sampling distance, land or water, and local time. In addition, one notices large scale seasonal effects that are latitude and longitude dependent. As a consequence, we obtain a cause-and-effect survey of pressure data peculiarities. One can then use background corrected pressure data to analyze seasonal effects within given latitude belts. Here time series of pressure data allow the tracking of high and low pressure areas together with the identification of their actual extent, velocity and life time. This information is vital to overall mass transport calculations and the determination of temporally varying gravity fields. However, one has to note that the satellite and ground-based instruments and the assimilation software being used for the pressure calculations will not remain the same over the years

  12. Favorable effect of aerobic exercise on arterial pressure and aortic pulse wave velocity during stress testing.

    Science.gov (United States)

    Milatz, Florian; Ketelhut, Sascha; Ketelhut, Sascha; Ketelhut, Reinhard G

    2015-07-01

    Increased central pulse wave velocity is a major risk factor for cardiovascular disease. The favorable influence of exercise on arterial stiffness (AS) and blood pressure (BP) has been reported exclusively at rest. The present study investigated the influence of a single bout of acute cycling on AS and BP during recovery and, moreover, during cold pressor stress testing. 32 healthy men (33.7 ± 8 years, BMI 24 ± 2.5 kg/m²) performed a 60 minute endurance exercise on a bicycle ergometer (45 % VO2max). Before and after exercise aortic pulse wave velocity (aPWV) as well as central and peripheral BP were measured non-invasively at rest and at the end of a 2 minute cold pressor test (CPT). Even after 60 minutes of recovery aPWV (- 0.22 ± 0.3 m / sec) was significantly reduced (p Exercise decreased peripheral (- 8 ± 7 mmHg) and central (- 7 ± 8 mmHg) systolic BP as well as peripheral (- 3 ± 5 mmHg) and central (- 4 ± 7 mmHg) diastolic BP (p exercise, there was a significant reduction in aPWV (- 0.19 ± 0.3 m / sec), peripheral (- 6 ± 10 mmHg) and central (- 5 ± 8 mmHg) systolic BP as well as peripheral (- 3 ± 6 mmHg) and central (- 3 ± 6 mmHg) diastolic BP during CPT after exercise (p exercise leads not only to decreased BP but even more reduces aPWV as a measure of AS even after 60 minutes of recovery. In particular, the investigation provides evidence that acute moderate-intensity exercise has a favorable effect on BP and aPWV during stress testing.

  13. Full-field wrist pulse signal acquisition and analysis by 3D Digital Image Correlation

    Science.gov (United States)

    Xue, Yuan; Su, Yong; Zhang, Chi; Xu, Xiaohai; Gao, Zeren; Wu, Shangquan; Zhang, Qingchuan; Wu, Xiaoping

    2017-11-01

    Pulse diagnosis is an essential part in four basic diagnostic methods (inspection, listening, inquiring and palpation) in traditional Chinese medicine, which depends on longtime training and rich experience, so computerized pulse acquisition has been proposed and studied to ensure the objectivity. To imitate the process that doctors using three fingertips with different pressures to feel fluctuations in certain areas containing three acupoints, we established a five dimensional pulse signal acquisition system adopting a non-contacting optical metrology method, 3D digital image correlation, to record the full-field displacements of skin fluctuations under different pressures. The system realizes real-time full-field vibration mode observation with 10 FPS. The maximum sample frequency is 472 Hz for detailed post-processing. After acquisition, the signals are analyzed according to the amplitude, pressure, and pulse wave velocity. The proposed system provides a novel optical approach for digitalizing pulse diagnosis and massive pulse signal data acquisition for various types of patients.

  14. Hydrophobic treatment on polymethylmethacrylate surface by nanosecond-pulse DBDs in CF4 at atmospheric pressure

    International Nuclear Information System (INIS)

    Zhang, Cheng; Zhou, Yang; Shao, Tao; Xie, Qing; Xu, Jiayu; Yang, Wenjin

    2014-01-01

    Highlights: • Increase in hydrophobicity on PMMA is achieved after the DBD treatment in CF 4 , and the water contact angle can increase from 68° to 100° after treatment. • Nanosecond-pulse DBD is used for the surface treatment and the power density is about 114.8 mW/cm 2 . • The effects of applied voltage, CF 4 flow, and time on plasma treatment are investigated. • Plasma treatment causes morphological change, significantly increases the roughness of the surface, and introduces fluorine-containing groups into the polymethylmethacrylate surface. • Hydrophobic behavior of the treated PMMA surface is slightly affected by the aging effect. - Abstract: Nanosecond-pulse dielectric barrier discharge (DBD) can provide non-thermal plasmas with extremely high energy and high density, which can result in a series of complicated physical and chemical reactions in the surface treatment of polymers. Therefore, in this paper, hydrophobic treatment of polymethylmethacrylate (PMMA) surface is conducted by nanosecond-pulse DBD in carbon tetrafluoride (CF 4 ) at atmospheric pressure. Investigations on surface morphology and chemical composition before and after the DBD treatment in CF 4 are conducted with the contact angle measurement, atomic force microscope, Fourier transform infrared spectroscopy, and X-ray photoelectron spectrometer. The effects of the applied voltage, CF 4 flow rate, and treatment time on the hydrophobic modification are studied. Results show that the contact angles of the treated PMMA surface increases with the applied voltage, and it could be greatly affected by the CF 4 flow rate and the treatment time. The water contact angle can increase from 68° to 100° after the treatment. Furthermore, both surface morphology and chemical composition of the PMMA samples are changed. Both the increase of the surface roughness and the occurrence of fluorine-containing functional groups on the PMMA surface treated by DBD in CF 4 lead to the hydrophobicity

  15. Sensitivity analysis of a PWR pressurizer

    International Nuclear Information System (INIS)

    Bruel, Renata Nunes

    1997-01-01

    A sensitivity analysis relative to the parameters and modelling of the physical process in a PWR pressurizer has been performed. The sensitivity analysis was developed by implementing the key parameters and theoretical model lings which generated a comprehensive matrix of influences of each changes analysed. The major influences that have been observed were the flashing phenomenon and the steam condensation on the spray drops. The present analysis is also applicable to the several theoretical and experimental areas. (author)

  16. Dependence of the absorption of pulsed CO2-laser radiation by silane on wavenumber, fluence, pulse duration, temperature, optical path length, and pressure of absorbing and nonabsorbing gases

    International Nuclear Information System (INIS)

    Blazejowski, J.; Gruzdiewa, L.; Rulewski, J.; Lampe, F.W.

    1995-01-01

    The absorption of three lines [P(20), 944.2 cm -1 ; P(14), 949.2 cm -1 ; and R(24), 978.5 cm -1 ] of the pulsed CO 2 laser (00 0 1--10 0 0 transition) by SiH 4 was measured at various pulse energy, pulse duration, temperature, optical path length, and pressure of the compound and nonabsorbing foreign gases. In addition, low intensity infrared absorption spectrum of silane was compared with high intensity absorption characteristics for all lines of the pulsed CO 2 laser. The experimental dependencies show deviations from the phenomenological Beer--Lambert law which can be considered as arising from the high intensity of an incident radiation and collisions of absorbing molecules with surroundings. These effects were included into the expression, being an extended form of the Beer--Lambert law, which reasonably approximates all experimental data. The results, except for extending knowledge on the interaction of a high power laser radiation with matter, can help understanding and planning processes leading to preparation of silicon-containing technologically important materials

  17. Validation of Noninvasive MOEMS-Assisted Measurement System Based on CCD Sensor for Radial Pulse Analysis

    Directory of Open Access Journals (Sweden)

    Rolanas Dauksevicius

    2013-04-01

    Full Text Available Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner’s subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation.

  18. Wave Intensity Analysis of Right Ventricular Function during Pulsed Operation of Rotary Left Ventricular Assist Devices.

    Science.gov (United States)

    Bouwmeester, J Christopher; Park, Jiheum; Valdovinos, John; Bonde, Pramod

    2018-05-29

    Changing the speed of left ventricular assist devices (LVADs) cyclically may be useful to restore aortic pulsatility; however, the effects of this pulsation on right ventricular (RV) function are unknown. This study investigates the effects of direct ventricular interaction by quantifying the amount of wave energy created by RV contraction when axial and centrifugal LVADs are used to assist the left ventricle. In 4 anesthetized pigs, pressure and flow were measured in the main pulmonary artery and wave intensity analysis was used to identify and quantify the energy of waves created by the RV. The axial pump depressed the intensity of waves created by RV contraction compared with the centrifugal pump. In both pump designs, there were only minor and variable differences between the continuous and pulsed operation on RV function. The axial pump causes the RV to contract with less energy compared with a centrifugal design. Diminishing the ability of the RV to produce less energy translates to less pressure and flow produced, which may lead to LVAD-induced RV failure. The effects of pulsed LVAD operation on the RV appear to be minimal during acute observation of healthy hearts. Further study is necessary to uncover the effects of other modes of speed modulation with healthy and unhealthy hearts to determine if pulsed operation will benefit patients by reducing LVAD complications.

  19. Non-invasive aortic systolic pressure and pulse wave velocity estimation in a primary care setting: An in silico study.

    Science.gov (United States)

    Guala, Andrea; Camporeale, Carlo; Ridolfi, Luca; Mesin, Luca

    2017-04-01

    Everyday clinical cardiovascular evaluation is still largely based on brachial systolic and diastolic pressures. However, several clinical studies have demonstrated the higher diagnostic capacities of the aortic pressure, as well as the need to assess the aortic mechanical properties (e.g., by measuring the aortic pulse wave velocity). In order to fill this gap, we propose to exploit a set of easy-to-obtain physical characteristics to estimate the aortic pressure and pulse wave velocity. To this aim, a large population of virtual subjects is created by a validated mathematical model of the cardiovascular system. Quadratic regressive models are then fitted and statistically selected in order to obtain reliable estimations of the aortic pressure and pulse wave velocity starting from the knowledge of the subject age, height, weight, brachial pressure, photoplethysmographic measures and either electrocardiogram or phonocardiogram. The results are very encouraging and foster clinical studies aiming to apply a similar technique to a real population. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Seal analysis technology for reactor pressure vessel

    International Nuclear Information System (INIS)

    Zheng Liangang; Zhang Liping; Yang Yu; Zang Fenggang

    2009-01-01

    There is the coolant with radiation, high temperature and high pressure in the reactor pressure vessel (RPV). It is closely correlated to RPV sealing capability whether the whole nuclear system work well or not. The aim of this paper is to study the seal analysis method and technology, such as the pre-tensioning of the bolt, elastoplastic contact and coupled technology of thermal and structure. The 3 D elastoplastic seal analysis method really and generally consider the loads and model the contact problem with friction between the contact plates. This method is easier than the specialized seal program and used widely. And it is more really than the 2 D seal analysis method. This 3 D elastoplastic seal analysis method has been successfully used in the design and analysis of RPV. (authors)

  1. PULSE WAVE VELOCITY AND CENTRAL AORTIC PRESSURE IN OBESE CHILDREN ACCORDING TO THE NON-INVASIVE ARTERIOGRAPHY RESULTS

    Directory of Open Access Journals (Sweden)

    O. V. Kozhevnikova

    2013-01-01

    Full Text Available The article presents information value of non-invasive arteriography, which reveals early signs of cardiovascular pathology formation in children, using a large number of trials in children. The authors examined predictors of cardiovascular catastrophes’ development, confirmed in adults: aortic wall’s stiffness, central aortic pressure and pulse pressure – that have not been sufficiently studied in children yet. The article shows that the high-technology method of non-invasive arteriography allows revealing changes of these parameters in children on the preclinical stage. It also shows their correlation with body mass index, fatty hepatosis, direct correlation of weight gain with connection of pulse wave velocity and central blood pressure and importance of follow-up evaluation of these parameters. Heterogeneity of the group of obese children in terms of these parameters is a premise for development of individual approach to control and prevention of cardiovascular complications’ development risk in childhood.

  2. Design by analysis of composite pressure equipment

    International Nuclear Information System (INIS)

    Durand, S.; Mallard, H.

    2004-01-01

    Design by analysis has been particularly pointed out by the european pressure equipment directive. Advanced mechanical analysis like finite element method are used instead of classical design by formulas or graphs. Structural behaviour can be understood by the designer. Design by analysis of metallic pressure equipments is widely used. Material behaviour or limits analysis is based on sophisticated approach (elasto-plastic analysis,..). Design by analysis of composite pressure equipments is not systematically used for industrial products. The difficulty comes from the number of information to handle. The laws of mechanics are the same for composite materials than for steel. The authors want to show that in design by analysis, the composite material approach is only more complete than the metallic approach. Mechanics is more general but not more complicated. A multi-material approach is a natural evolution of design by analysis of composite equipments. The presentation is illustrated by several industrial cases - composite vessel: analogy with metallic calculations; - composite pipes and fittings; - welding and bounding of thermoplastic equipments. (authors)

  3. Noncircular plasma shape analysis in long-pulse current drive experiment in TRIAM-1M

    International Nuclear Information System (INIS)

    Minooka, Mayumi; Kawasaki, Shoji; Jotaki, Eriko; Moriyama, Shin-ichi; Nagao, Akihiro; Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi

    1991-01-01

    Plasma cross section was noncircularized and the plasma shape was analyzed in order to study the characteristics of the plasma in long-pulse current drive experiments in high-field superconducting tokamak TRIAM-1M. Filament approximation method was adopted, since on-line processing by data processing computer is possible. The experiments of the noncircularization were carried out during 30-to 60-sec discharges. As a result, it became clear that D-shape plasma of elongation ratio 1.4 was maintained stably. By the analysis the internal inductance and poloidal beta were assessed, and so informations about the plasma current profile and internal pressure were obtained. (author)

  4. A feasibility study on age-related factors of wrist pulse using principal component analysis.

    Science.gov (United States)

    Jang-Han Bae; Young Ju Jeon; Sanghun Lee; Jaeuk U Kim

    2016-08-01

    Various analysis methods for examining wrist pulse characteristics are needed for accurate pulse diagnosis. In this feasibility study, principal component analysis (PCA) was performed to observe age-related factors of wrist pulse from various analysis parameters. Forty subjects in the age group of 20s and 40s were participated, and their wrist pulse signal and respiration signal were acquired with the pulse tonometric device. After pre-processing of the signals, twenty analysis parameters which have been regarded as values reflecting pulse characteristics were calculated and PCA was performed. As a results, we could reduce complex parameters to lower dimension and age-related factors of wrist pulse were observed by combining-new analysis parameter derived from PCA. These results demonstrate that PCA can be useful tool for analyzing wrist pulse signal.

  5. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  6. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    International Nuclear Information System (INIS)

    Chen Baozhen; Huang Zuqia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  7. Analysis of nuclear reactor pressure vessel flanges

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de; Augusto, O.B.

    1985-01-01

    This work proposes a methodology for the structural analysis of high diameter nuclear reactor pressure vessel flanges. In the analysis the vessel is divided into shell-of-revolution elements, the flanges are represented by rigid rings, and the bolts are treated as beams. The flexibility method is used for solving the problem, and the results are compared with results obtained by the finite element method. (Author) [pt

  8. Time series analysis of barometric pressure data

    International Nuclear Information System (INIS)

    La Rocca, Paola; Riggi, Francesco; Riggi, Daniele

    2010-01-01

    Time series of atmospheric pressure data, collected over a period of several years, were analysed to provide undergraduate students with educational examples of application of simple statistical methods of analysis. In addition to basic methods for the analysis of periodicities, a comparison of two forecast models, one based on autoregression algorithms, and the other making use of an artificial neural network, was made. Results show that the application of artificial neural networks may give slightly better results compared to traditional methods.

  9. Association of pulse pressure with new-onset atrial fibrillation in patients with hypertension and left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Larstorp, Anne Cecilie K; Ariansen, Inger; Gjesdal, Knut

    2012-01-01

    , and mean arterial pressure. When evaluated in the same model, the predictive effect of systolic and diastolic blood pressures together was similar to that of PP. In this population of patients with hypertension and left ventricular hypertrophy, PP was the strongest single blood pressure predictor of new......Previous studies have found pulse pressure (PP), a marker of arterial stiffness, to be an independent predictor of atrial fibrillation (AF) in general and hypertensive populations. We examined whether PP predicted new-onset AF in comparison with other blood pressure components in the Losartan...... Intervention For Endpoint reduction in hypertension study, a double-blind, randomized (losartan versus atenolol), parallel-group study, including 9193 patients with hypertension and electrocardiographic left ventricular hypertrophy. In 8810 patients with neither a history of AF nor AF at baseline, Minnesota...

  10. An experimental investigation on the pressure characteristics of high speed self-resonating pulsed waterjets influenced by feeding pipe diameter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dong; Kang, Dong; Ding, Xiao Long; Wang, Xiao Huan; Fang, Zhen Long [School of Power and Mechanical Engineering, Wuhan University, Hubei Province (China)

    2016-11-15

    The destructive power of a continuous waterjet issuing from a nozzle can be greatly enhanced by generating self-resonance in the nozzle assembly to produce a Self-resonating pulsed waterjet (SRPW). To further improve the performance of SRPW, effects of feeding pipe diameter on the pressure characteristics were experimentally investigated by measuring and analyzing the axial pressure oscillation peaks and amplitudes. Four organ-pipe nozzles of different chamber lengths and three feeding pipes of different diameters were employed. Results show that feeding pipe diameter cannot change the feature of SRPW of having an optimum standoff distance, but it slightly changes the oscillating frequency of the jet. It is also found that feeding pipe diameter significantly affects the magnitudes of pressure oscillation peak and amplitude, largely depending on the pump pressure and standoff distance. The enhancement or attenuation of the pressure oscillation peak and amplitude can be differently affected by the same feeding pipe diameter.

  11. Nonlinear behaviors in a pulsed dielectric barrier discharge at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jiao; Wang Yanhui, E-mail: wangyh@dlut.edu.cn; Wang Dezhen

    2011-08-01

    In this paper, the temporal nonlinear behaviors of pulsed dielectric barrier discharge in atmospheric helium are studied numerically by a one-dimensional fluid model. The results show that the common single-period pulsed discharge with two current pulses per single voltage pulse can take place over a broad parameter range. The rising and falling times of the voltage pulse can affect the discharge characteristics greatly. When the discharge is ignited by a pulse voltage with long rising and falling times, a single-period pulsed discharge with multiple current peaks can be observed. Under appropriate rising and falling times of the voltage pulse, a stable period-two discharge can occur over wide frequency and voltage ranges. Also this period-two discharge can exhibit different current and voltage characteristics with changing the duty cycle. With other parameters fixed, the pulsed DBD could be driven to chaos through period-doubling route by increasing either the falling time or the frequency of voltage pulse.

  12. The Formation of a Power Multi-Pulse Extreme Ultraviolet Radiation in the Pulse Plasma Diode of Low Pressure

    Directory of Open Access Journals (Sweden)

    Ievgeniia V. Borgun

    2013-01-01

    Full Text Available In this paper results are presented on experimental studies of the temporal characteristics of spike extreme ultraviolet (EUV radiation in the spectral range of 12.2 ÷ 15.8 nm from the anode region of high-current (I = 40 kA pulsed discharges in tin vapor. It is observed that the intense multi-spike radiation in this range arises at an inductive stage of the discharge. It has been shown that the radiation spikes correlate with the sharp increase of active resistance and of pumped power, due to plasma heating by an electron beam, formed in the double layer of charged particles. It has been observed that for large number of spikes the conversion efficiency of pumped energy into radiationat double layer formation is essentially higher in comparison with collisional heating.

  13. The use of joint time frequency analysis to quantify the effect of ventilation on the pulse oximeter waveform.

    Science.gov (United States)

    Shelley, Kirk H; Awad, Aymen A; Stout, Robert G; Silverman, David G

    2006-04-01

    In the process of determining oxygen saturation, the pulse oximeter functions as a photoelectric plethysmograph. By analyzing how the frequency spectrum of the pulse oximeter waveform changes over time, new clinically relevant features can be extracted. Thirty patients undergoing general anesthesia for abdominal surgery had their pulse oximeter, airway pressure and CO(2) waveforms collected (50 Hz). The pulse oximeter waveform was analyzed with a short-time Fourier transform using a moving 4096 point Hann window of 82 seconds duration. The frequency signal created by positive pressure ventilation was extracted using a peak detection algorithm in the frequency range of ventilation (0.08-0.4 Hz = 5-24 breaths/minute). The respiratory rate derived in this manner was compared to the respiratory rate as determined by CO(2) detection. In total, 52 hours of telemetry data were analyzed. The respiratory rate measured from the pulse oximeter waveform was found to have a 0.89 linear correlation when compared to CO(2) detection and airway pressure change. the bias was 0.03 breath/min, SD was 0.557 breath/min and the upper and lower limits of agreement were 1.145 and -1.083 breath/min respectively. The presence of motion artifact proved to be the primary cause of failure of this technique. Joint time frequency analysis of the pulse oximeter waveform can be used to determine the respiratory rate of ventilated patients and to quantify the impact of ventilation on the waveform. In addition, when applied to the pulse oximeter waveform new clinically relevant features were observed.

  14. Diagnosis of a short-pulse dielectric barrier discharge at atmospheric pressure in helium with hydrogen-methane admixtures

    Science.gov (United States)

    Nastuta, A. V.; Pohoata, V.; Mihaila, I.; Topala, I.

    2018-04-01

    In this study, we present results from electrical, optical, and spectroscopic diagnosis of a short-pulse (250 ns) high-power impulse (up to 11 kW) dielectric barrier discharge at atmospheric pressure running in a helium/helium-hydrogen/helium-hydrogen-methane gas mixture. This plasma source is able to generate up to 20 cm3 of plasma volume, pulsed in kilohertz range. The plasma spatio-temporal dynamics are found to be developed in three distinct phases. All the experimental observations reveal a similar dynamic to medium power microsecond barrier discharges, although the power per pulse and current density are up to two orders of magnitude higher than the case of microsecond barrier discharges. This might open the possibility for new applications in the field of gas or surface processing, and even life science. These devices can be used in laboratory experiments relevant for molecular astrophysics.

  15. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials.

    Science.gov (United States)

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H; Azad, Abul; Marshall, Bruce; La Lone, Brandon M; Henson, Bryan; Smilowitz, Laura

    2015-06-01

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 G Samples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO3. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L-4) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. Both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.

  16. Comparison of the quantitative analysis performance between pulsed voltage atom probe and pulsed laser atom probe

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, J., E-mail: takahashi.3ct.jun@jp.nssmc.com [Advanced Technology Research Laboratories, Nippon Steel & Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511 (Japan); Kawakami, K. [Advanced Technology Research Laboratories, Nippon Steel & Sumitomo Metal Corporation, 20-1 Shintomi, Futtsu-city, Chiba 293-8511 (Japan); Raabe, D. [Max-Planck Institut für Eisenforschung GmbH, Department for Microstructure Physics and Alloy Design, Max-Planck-Str. 1, 40237 Düsseldorf (Germany)

    2017-04-15

    Highlights: • Quantitative analysis in Fe-Cu alloy was investigated in voltage and laser atom probe. • In voltage-mode, apparent Cu concentration exceeded actual concentration at 20–40 K. • In laser-mode, the concentration never exceeded the actual concentration even at 20 K. • Detection loss was prevented due to the rise in tip surface temperature in laser-mode. • Preferential evaporation of solute Cu was reduced in laser-mode. - Abstract: The difference in quantitative analysis performance between the voltage-mode and laser-mode of a local electrode atom probe (LEAP3000X HR) was investigated using a Fe-Cu binary model alloy. Solute copper atoms in ferritic iron preferentially field evaporate because of their significantly lower evaporation field than the matrix iron, and thus, the apparent concentration of solute copper tends to be lower than the actual concentration. However, in voltage-mode, the apparent concentration was higher than the actual concentration at 40 K or less due to a detection loss of matrix iron, and the concentration decreased with increasing specimen temperature due to the preferential evaporation of solute copper. On the other hand, in laser-mode, the apparent concentration never exceeded the actual concentration, even at lower temperatures (20 K), and this mode showed better quantitative performance over a wide range of specimen temperatures. These results indicate that the pulsed laser atom probe prevents both detection loss and preferential evaporation under a wide range of measurement conditions.

  17. Ramadan fasting ameliorates arterial pulse pressure and lipid profile, and alleviates oxidative stress in hypertensive patients.

    Science.gov (United States)

    Al-Shafei, Ahmad I M

    2014-06-01

    Effects of Ramadan fasting on health are important. Its effects on arterial pulse pressure (PP), lipid profile and oxidative stress were characterized in hypertensives. PP, indices of lipid profile and oxidative stress were measured pre-, during and post-fasting in equal (40 each), sex- and age-matched groups (age 55 ± 5 years) of hypertensives (HT) and controls (C). Fasting reduced PP significantly by 17.2% and insignificantly by 9.3% in the HT and C groups, respectively. Total cholesterol (TC) was lowered insignificantly by 11.7% and 4.7% in the HT and C patients, respectively. Triglycerides (TG) and malondialdehyde (MDA) were significantly lowered by: TG: 24.5% and 22.8%; MDA: 45.6% and 54.3%; while glutathione (GSH) elevated by 56.8% and 52.6% in the HT and C groups, respectively. High-density lipoproteins (HDL) were raised significantly by 33.3% and insignificantly by 6.7%, whereas low-density lipoproteins (LDL) decreased significantly by 17.7% and insignificantly by 4.0% in the HT and C groups, respectively. At 6 weeks post-fasting, MDA remained significantly lower than the pre-fasting level by 24.3% and 25.7%, and GSH higher by 30.2% and 26.3% in the HT and C groups, respectively, while PP and TC returned to pre-fasting values in both groups. The post-fasting, HDL was significantly higher by 20.3% and LDL lower by 12.0% than the fasting levels in the HT patients. Fasting improves PP and lipids profile and ameliorates oxidative stress in hypertensives.

  18. Intraocular pressure and ocular pulse amplitude using dynamic contour tonometry and contact lens tonometry.

    Science.gov (United States)

    Hoffmann, Esther M; Grus, Franz-H; Pfeiffer, Norbert

    2004-03-23

    The new Ocular Dynamic Contour Tonometer (DCT), investigational device supplied by SMT (Swiss Microtechnology AG, Switzerland) allows simultaneous recording of intraocular pressure (IOP) and ocular pulse amplitude (OPA). It was the aim of this study to compare the IOP results of this new device with Goldmann tonometry. Furthermore, IOP and OPA measured with the new slitlamp-mounted DCT were compared to the IOP and OPA measured with the hand-held SmartLens,a gonioscopic contact lens tonometer (ODC Ophthalmic Development Company AG, Switzerland). Nineteen healthy subjects were included in this study. IOP was determined by three consecutive measurements with each of the DCT, SmartLens, and Goldmann tonometer. Furthermore, OPA was measured three times consecutively by DCT and SmartLens. No difference (P = 0.09) was found between the IOP values by means of DCT (mean: 16.6 mm Hg, median: 15.33 mm Hg, SD: +/- 4.04 mm Hg) and Goldmann tonometry (mean: 16.17 mm Hg, median: 15.33 mm Hg, SD: +/- 4.03 mm Hg). The IOP values of SmartLens (mean: 20.25 mm Hg, median: 19.00 mm Hg, SD: +/- 4.96 mm Hg) were significantly higher (P = 0.0008) both from Goldmann tonometry and DCT. The OPA values of the DCT (mean: 3.08 mm Hg, SD: +/- 0.92 mm Hg) were significantly lower (P = 0.0003) than those obtained by SmartLens (mean: 3.92 mm Hg, SD: +/- 0.83 mm Hg). DCT was equivalent to Goldmann applanation tonometry in measurement of IOP in a small group of normal subjects. In contrast, SmartLens (contact lens tonometry) gave IOP readings that were significantly higher compared with Goldmann applanation tonometer readings. Both devices, DCT and SmartLens provide the measurement of OPA which could be helpful e.g. for the management of glaucoma.

  19. Validation of the inverse pulse wave transit time series as surrogate of systolic blood pressure in MVAR modeling.

    Science.gov (United States)

    Giassi, Pedro; Okida, Sergio; Oliveira, Maurício G; Moraes, Raimes

    2013-11-01

    Short-term cardiovascular regulation mediated by the sympathetic and parasympathetic branches of the autonomic nervous system has been investigated by multivariate autoregressive (MVAR) modeling, providing insightful analysis. MVAR models employ, as inputs, heart rate (HR), systolic blood pressure (SBP) and respiratory waveforms. ECG (from which HR series is obtained) and respiratory flow waveform (RFW) can be easily sampled from the patients. Nevertheless, the available methods for acquisition of beat-to-beat SBP measurements during exams hamper the wider use of MVAR models in clinical research. Recent studies show an inverse correlation between pulse wave transit time (PWTT) series and SBP fluctuations. PWTT is the time interval between the ECG R-wave peak and photoplethysmography waveform (PPG) base point within the same cardiac cycle. This study investigates the feasibility of using inverse PWTT (IPWTT) series as an alternative input to SBP for MVAR modeling of the cardiovascular regulation. For that, HR, RFW, and IPWTT series acquired from volunteers during postural changes and autonomic blockade were used as input of MVAR models. Obtained results show that IPWTT series can be used as input of MVAR models, replacing SBP measurements in order to overcome practical difficulties related to the continuous sampling of the SBP during clinical exams.

  20. Amplification of pressure waves in laser-assisted endodontics with synchronized delivery of Er:YAG laser pulses.

    Science.gov (United States)

    Lukač, Nejc; Jezeršek, Matija

    2018-05-01

    When attempting to clean surfaces of dental root canals with laser-induced cavitation bubbles, the resulting cavitation oscillations are significantly prolonged due to friction on the cavity walls and other factors. Consequently, the collapses are less intense and the shock waves that are usually emitted following a bubble's collapse are diminished or not present at all. A new technique of synchronized laser-pulse delivery intended to enhance the emission of shock waves from collapsed bubbles in fluid-filled endodontic canals is reported. A laser beam deflection probe, a high-speed camera, and shadow photography were used to characterize the induced photoacoustic phenomena during synchronized delivery of Er:YAG laser pulses in a confined volume of water. A shock wave enhancing technique was employed which consists of delivering a second laser pulse at a delay with regard to the first cavitation bubble-forming laser pulse. Influence of the delay between the first and second laser pulses on the generation of pressure and shock waves during the first bubble's collapse was measured for different laser pulse energies and cavity volumes. Results show that the optimal delay between the two laser pulses is strongly correlated with the cavitation bubble's oscillation period. Under optimal synchronization conditions, the growth of the second cavitation bubble was observed to accelerate the collapse of the first cavitation bubble, leading to a violent collapse, during which shock waves are emitted. Additionally, shock waves created by the accelerated collapse of the primary cavitation bubble and as well of the accompanying smaller secondary bubbles near the cavity walls were observed. The reported phenomena may have applications in improved laser cleaning of surfaces during laser-assisted dental root canal treatments.

  1. Pulse pressure is not an independent predictor of outcome in type 2 diabetes patients with chronic kidney disease and anemia

    DEFF Research Database (Denmark)

    Theilade, S; Claggett, B; Hansen, T W

    2015-01-01

    Pulse pressure (PP) remains an elusive cardiovascular risk factor with inconsistent findings. We clarified the prognostic value in patients with type 2 diabetes, chronic kidney disease (CKD) and anemia in the Trial to Reduce cardiovascular Events with Aranesp (darbepoetin alfa) Therapy. In 4038......, CKD and anemia, PP did not independently predict cardiovascular events or ESRD. This may reflect confounding by aggressive antihypertensive treatment, or PP may be too rough a risk marker in these high-risk patients....

  2. Double pulse laser induced breakdown spectroscopy of a solid in water: Effect of hydrostatic pressure on laser induced plasma, cavitation bubble and emission spectra

    Science.gov (United States)

    López-Claros, M.; Dell'Aglio, M.; Gaudiuso, R.; Santagata, A.; De Giacomo, A.; Fortes, F. J.; Laserna, J. J.

    2017-07-01

    There is a growing interest in the development of sensors use in exploration of the deep ocean. Techniques for the chemical analysis of submerged solids are of special interest, as they show promise for subsea mining applications where a rapid sorting of materials found in the sea bottom would improve efficiency. Laser-Induced Breakdown Spectroscopy (LIBS) has demonstrated potential for this application thanks to its unique capability of providing the atomic composition of submerged solids. Here we present a study on the parameters that affect the spectral response of metallic targets in an oceanic pressure environment. Following laser excitation of the solid, the plasma persistence and the cavitation bubble size are considerably reduced as the hydrostatic pressure increases. These effects are of particular concern in dual pulse excitation as reported here, where a careful choice of the interpulse timing is required. Shadowgraphic images of the plasma demonstrate that cavitation bubbles are formed early after the plasma onset and that the effect of hydrostatic pressure is negligible during the early stage of plasma expansion. Contrarily to what is observed at atmospheric pressure, emission spectra observed at high pressures are characterized by self-absorbed atomic lines on continuum radiation resulting from strong radiative recombination in the electron-rich confined environment. This effect is much less evident with ionic lines due to the much higher energy of the levels involved and ionization energy of ions, as well as to the lower extent of absorption effects occurring in the inner part of the plasma, where ionized species are more abundant. As a result of the smaller shorter-lived cavitation bubble, the LIBS intensity enhancement resulting from dual pulse excitation is reduced when the applied pressure increases.

  3. Reliability model analysis and primary experimental evaluation of laser triggered pulse trigger

    International Nuclear Information System (INIS)

    Chen Debiao; Yang Xinglin; Li Yuan; Li Jin

    2012-01-01

    High performance pulse trigger can enhance performance and stability of the PPS. It is necessary to evaluate the reliability of the LTGS pulse trigger, so we establish the reliability analysis model of this pulse trigger based on CARMES software, the reliability evaluation is accord with the statistical results. (authors)

  4. Electrical and optical analysis of fast transient discharges in a pulsed corona pilot unit

    NARCIS (Netherlands)

    Blom, P.P.M.; Smulders, H.W.M.; Heesch, van E.J.M.; Laan, van der P.C.T.

    1997-01-01

    We give a detailed analysis of intense pulsed corona dis charges. CCD movies and current, voltage and energy in put measurements are the basis of the description. The discharges are generated in a 1.5 kW pilot unit, which cre ates pulsed corona discharges energized by 100 kV pulses of 200 us width,

  5. Constrained independent component analysis approach to nonobtrusive pulse rate measurements

    Science.gov (United States)

    Tsouri, Gill R.; Kyal, Survi; Dianat, Sohail; Mestha, Lalit K.

    2012-07-01

    Nonobtrusive pulse rate measurement using a webcam is considered. We demonstrate how state-of-the-art algorithms based on independent component analysis suffer from a sorting problem which hinders their performance, and propose a novel algorithm based on constrained independent component analysis to improve performance. We present how the proposed algorithm extracts a photoplethysmography signal and resolves the sorting problem. In addition, we perform a comparative study between the proposed algorithm and state-of-the-art algorithms over 45 video streams using a finger probe oxymeter for reference measurements. The proposed algorithm provides improved accuracy: the root mean square error is decreased from 20.6 and 9.5 beats per minute (bpm) for existing algorithms to 3.5 bpm for the proposed algorithm. An error of 3.5 bpm is within the inaccuracy expected from the reference measurements. This implies that the proposed algorithm provided performance of equal accuracy to the finger probe oximeter.

  6. Thermohydraulic analysis of pressurized water reactors

    International Nuclear Information System (INIS)

    Veloso, M.A.

    1980-01-01

    The computer program PANTERA is applied in the thermo-hydraulic analysis of Pressurized Water Reactor Cores (PWR). It is a version of COBRA-IIIC in which a new thermal conduction model for fuel rods was introduced. The results calculated by this program are compared with experimental data obtained from bundles of fuel rods, simulating reactor conditions. The validity of the new thermal model is checked too. The PANTERA code, through a simplified procedure of calculation, is used in the thermo-hydraulic analysis of Indian Point, Unit 2, reactor core, in stationary conditions. The results are discussed and compared with design data. (Autor) [pt

  7. Reliability analysis of reactor pressure vessel intensity

    International Nuclear Information System (INIS)

    Zheng Liangang; Lu Yongbo

    2012-01-01

    This paper performs the reliability analysis of reactor pressure vessel (RPV) with ANSYS. The analysis method include direct Monte Carlo Simulation method, Latin Hypercube Sampling, central composite design and Box-Behnken Matrix design. The RPV integrity reliability under given input condition is proposed. The result shows that the effects on the RPV base material reliability are internal press, allowable basic stress and elasticity modulus of base material in descending order, and the effects on the bolt reliability are allowable basic stress of bolt material, preload of bolt and internal press in descending order. (authors)

  8. Comparison of the quantitative analysis performance between pulsed voltage atom probe and pulsed laser atom probe.

    Science.gov (United States)

    Takahashi, J; Kawakami, K; Raabe, D

    2017-04-01

    The difference in quantitative analysis performance between the voltage-mode and laser-mode of a local electrode atom probe (LEAP3000X HR) was investigated using a Fe-Cu binary model alloy. Solute copper atoms in ferritic iron preferentially field evaporate because of their significantly lower evaporation field than the matrix iron, and thus, the apparent concentration of solute copper tends to be lower than the actual concentration. However, in voltage-mode, the apparent concentration was higher than the actual concentration at 40K or less due to a detection loss of matrix iron, and the concentration decreased with increasing specimen temperature due to the preferential evaporation of solute copper. On the other hand, in laser-mode, the apparent concentration never exceeded the actual concentration, even at lower temperatures (20K), and this mode showed better quantitative performance over a wide range of specimen temperatures. These results indicate that the pulsed laser atom probe prevents both detection loss and preferential evaporation under a wide range of measurement conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Dye laser spectrometer for the analysis of pulsed vacuum arcs

    International Nuclear Information System (INIS)

    Hargis, P.J. Jr.; Robertson, M.M.

    1975-01-01

    A pulsed dye laser spectrometer which is used to obtain detailed single shot spectroscopic measurements of the plasma in a pulsed vacuum arc was developed. The capabilities of this spectrometer are indicated by the detection of laser induced fluorescence signals from 10 6 neutral Ti atoms in the plasma of a pulsed vacuum arc with a Ti anode. (U.S.)

  10. 24-hour central aortic systolic pressure and 24-hour central pulse pressure are related to diabetic complications in type 1 diabetes - a cross-sectional study

    DEFF Research Database (Denmark)

    Theilade, Simone; Lajer, Maria Stenkil; Hansen, Tine Willum

    2013-01-01

    BACKGROUND: Non-invasive measurements of 24 hour ambulatory central aortic systolic pressure (24 h-CASP) and central pulse pressure (24 h-CPP) are now feasible. We evaluate the relationship between 24 h central blood pressure and diabetes-related complications in patients with type 1 diabetes.......68) and 3.72 (1.85-7.47) and autonomic dysfunction: 3.25 (1.65-6.41), 1.64 (1.12-2.39) and 2.89 (1.54-5.42). CONCLUSIONS: 24 h-CASP and 24 h-CPP was higher in patients vs. controls and increased with diabetic complications independently of covariates. Furthermore, 24 h-CASP was stronger associated....... METHODS: The study was cross-sectional, including 715 subjects: 86 controls (C), 69 patients with short diabetes duration (diabetes (≥ 10 years) and normoalbuminuria (LN), 163...

  11. A Fast Multimodal Ectopic Beat Detection Method Applied for Blood Pressure Estimation Based on Pulse Wave Velocity Measurements in Wearable Sensors.

    Science.gov (United States)

    Pflugradt, Maik; Geissdoerfer, Kai; Goernig, Matthias; Orglmeister, Reinhold

    2017-01-14

    Automatic detection of ectopic beats has become a thoroughly researched topic, with literature providing manifold proposals typically incorporating morphological analysis of the electrocardiogram (ECG). Although being well understood, its utilization is often neglected, especially in practical monitoring situations like online evaluation of signals acquired in wearable sensors. Continuous blood pressure estimation based on pulse wave velocity considerations is a prominent example, which depends on careful fiducial point extraction and is therefore seriously affected during periods of increased occurring extrasystoles. In the scope of this work, a novel ectopic beat discriminator with low computational complexity has been developed, which takes advantage of multimodal features derived from ECG and pulse wave relating measurements, thereby providing additional information on the underlying cardiac activity. Moreover, the blood pressure estimations' vulnerability towards ectopic beats is closely examined on records drawn from the Physionet database as well as signals recorded in a small field study conducted in a geriatric facility for the elderly. It turns out that a reliable extrasystole identification is essential to unsupervised blood pressure estimation, having a significant impact on the overall accuracy. The proposed method further convinces by its applicability to battery driven hardware systems with limited processing power and is a favorable choice when access to multimodal signal features is given anyway.

  12. Sandia Pulsed Reactor Facility (SPRF) calculator-assisted pulse analysis and display system

    International Nuclear Information System (INIS)

    Estes, B.F.; Berry, D.T.

    1980-02-01

    Two solid-metal fast burst type reactors (SPR II and SPR III) are operated at the Sandia Pulsed Reactor Facility. Since startup of the reactors, oscilloscope traces have been used to record (by camera) the pulse (power) shape while log N systems have measured initial reactor period. Virtually no other pulse information is available. A decision was made to build a system that could collect the basic input data available from the reactor - fission chambers, photodiodes, and thermocouples - condition the signals and output the various parameters such as power, energy, temperature, period and lifetime on hard copy that would provide a record for operations personnel as well as the experimenter. Because the reactors operate in short time frames - pulse operation - it is convenient to utilize the classical Nordheim-Fuchs approximation of the diffusion equation to describe reactor behavior. This report describes the work performed to date in developing the calculator system and analytical models for computing the desired parameters

  13. Pulse radiolysis experiments: synthesis and analysis of composite spectra

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, R H; Buzzard, G K [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Chemistry

    1976-01-01

    Methods are outlined for compiling optical spectra obtained in pulse radiolysis experiments in a form suitable for detailed synthesis and analysis of composite spectra. The experimental data are processed with a programmable calculator having a cassette recorder for the storage of the output data files and a peripheral plotter. The spectra are first smoothed by fitting them parabolically segment by segment. The overall spectrum is then assembled in digital form by interpolating the fitted data on a 1 nm grid and the results are stored on cassette files for further processing. Composite spectra can be readily calculated and plotted from the data on these files or known components can be subtracted from observed spectra to examine underlying contributions. The use of the fairly simple data processing methods described here permits an interactive mode of operation by the investigator which can maximize insight into details of the various contributions to an observed spectrum. Several examples of the use of these methods in conjunction with data obtained with a computer controlled pulse radiolysis data acquisition system are given.

  14. A Pulse Wave Velocity Based Method to Assess the Mean Arterial Blood Pressure Limits of Autoregulation in Peripheral Arteries

    Directory of Open Access Journals (Sweden)

    Ananya Tripathi

    2017-11-01

    Full Text Available Background: Constant blood flow despite changes in blood pressure, a phenomenon called autoregulation, has been demonstrated for various organ systems. We hypothesized that by changing hydrostatic pressures in peripheral arteries, we can establish these limits of autoregulation in peripheral arteries based on local pulse wave velocity (PWV.Methods: Electrocardiogram and plethysmograph waveforms were recorded at the left and right index fingers in 18 healthy volunteers. Each subject changed their left arm position, keeping the right arm stationary. Pulse arrival times (PAT at both fingers were measured and used to calculate PWV. We calculated ΔPAT (ΔPWV, the differences between the left and right PATs (PWVs, and compared them to the respective calculated blood pressure at the left index fingertip to derive the limits of autoregulation.Results: ΔPAT decreased and ΔPWV increased exponentially at low blood pressures in the fingertip up to a blood pressure of 70 mmHg, after which changes in ΔPAT and ΔPWV were minimal. The empirically chosen 20 mmHg window (75–95 mmHg was confirmed to be within the autoregulatory limit (slope = 0.097, p = 0.56. ΔPAT and ΔPWV within a 20 mmHg moving window were not significantly different from the respective data points within the control 75–95 mmHg window when the pressure at the fingertip was between 56 and 110 mmHg for ΔPAT and between 57 and 112 mmHg for ΔPWV.Conclusions: Changes in hydrostatic pressure due to changes in arm position significantly affect peripheral arterial stiffness as assessed by ΔPAT and ΔPWV, allowing us to estimate peripheral autoregulation limits based on PWV.

  15. Correlation of pulse wave velocity with left ventricular mass in patients with hypertension once blood pressure has been normalized

    Directory of Open Access Journals (Sweden)

    Siu H. Chan

    2012-02-01

    Full Text Available Vascular stiffness has been proposed as a simple method to assess arterial loading conditions of the heart which induce left ventricular hypertrophy (LVH. There is some controversy as to whether the relationship of vascular stiffness to LVH is independent of blood pressure, and which measurement of arterial stiffness, augmentation index (AI or pulse wave velocity (PWV is best. Carotid pulse wave contor and pulse wave velocity of patients (n=20 with hypertension whose blood pressure (BP was under control (<140/90 mmHg with antihypertensive drug treatment medications, and without valvular heart disease, were measured. Left ventricular mass, calculated from 2D echocardiogram, was adjusted for body size using two different methods: body surface area and height. There was a significant (P<0.05 linear correlation between LV mass index and pulse wave velocity. This was not explained by BP level or lower LV mass in women, as there was no significant difference in PWV according to gender (1140.1+67.8 vs 1110.6+57.7 cm/s. In contrast to PWV, there was no significant correlation between LV mass and AI. In summary, these data suggest that aortic vascular stiffness is an indicator of LV mass even when blood pressure is controlled to less than 140/90 mmHg in hypertensive patients. The data further suggest that PWV is a better proxy or surrogate marker for LV mass than AI and the measurement of PWV may be useful as a rapid and less expensive assessment of the presence of LVH in this patient population.

  16. Analysis of pulse-shape discrimination techniques for BC501A using GHz digital signal processing

    International Nuclear Information System (INIS)

    Rooney, B.D.; Dinwiddie, D.R.; Nelson, M.A.; Rawool-Sullivan, Mohini W.

    2001-01-01

    A comparison study of pulse-shape analysis techniques was conducted for a BC501A scintillator using digital signal processing (DSP). In this study, output signals from a preamplifier were input directly into a 1 GHz analog-to-digital converter. The digitized data obtained with this method was post-processed for both pulse-height and pulse-shape information. Several different analysis techniques were evaluated for neutron and gamma-ray pulse-shape discrimination. It was surprising that one of the simplest and fastest techniques resulted in some of the best pulse-shape discrimination results. This technique, referred to here as the Integral Ratio technique, was able to effectively process several thousand detector pulses per second. This paper presents the results and findings of this study for various pulse-shape analysis techniques with digitized detector signals.

  17. Detailed precision and accuracy analysis of swarm parameters from a pulsed Townsend experiment

    Science.gov (United States)

    Haefliger, P.; Franck, C. M.

    2018-02-01

    A newly built pulsed Townsend experimental setup which allows one to measure both electron and ion currents is presented. The principle of pulsed Townsend measurements itself is well established to obtain swarm parameters such as the effective ionization rate coefficient, the density-reduced mobility, and the density-normalized longitudinal diffusion coefficient. The main novelty of the present contribution is a detailed and comprehensive analysis of the entire measurement and evaluation chain with respect to accuracy, precision, and reproducibility. The influence of the input parameters (gap distance, applied voltage, measured pressure, and temperature) is analyzed in detail. An overall accuracy of ±0.5% in the density reduced electric field (E/N) is achieved, which is close to the theoretically possible limit using the chosen components. The precision of the experimental results is higher than the accuracy. Through an extensive measurement campaign, the repeatability of our measurements proved to be high and similar to the precision. The reproducibility of results at identical (E/N) is similar to the precision for different distances but decreases for varying pressures. For benchmark purposes, measurements for Ar, CO2, and N2 are presented and compared with our previous experimental setup, simulations, and other experimental references.

  18. Bacteria killing effect of pulsed plasmas in oxygen+air at atmospheric pressure

    International Nuclear Information System (INIS)

    Akan, T.

    2005-01-01

    Bacteria Killing Method. The high voltage pulsed plasma is a non-equilibrium plasma and generates UV photons, ozone and active oxygen. The aim of this paper is to present a simple device to generate plasma able to kill efficiently bacteria. One of the probes charged with bacteria, was kept as a control probes (not exposed to the pulsed plasma), the rest of the probes were exposed to the pulsed plasma and afterwards compared with above mentioned control probe (reference sample). During treatment the bacteria were exposed to the active atoms, molecules, charged particles and photons generated by the pulsed plasma. The temperature of the support of samples with bacteria exposed to plasma increased during the treatment with only 1-2 degrees. Full killing time of Staphylococcus species as low as 3 minutes have been obtained quite easily

  19. Intraocular pressure and ocular pulse amplitude using dynamic contour tonometry and contact lens tonometry

    Directory of Open Access Journals (Sweden)

    Grus Franz-H

    2004-03-01

    Full Text Available Abstract Background The new Ocular Dynamic Contour Tonometer (DCT, investigational device supplied by SMT (Swiss Microtechnology AG, Switzerland allows simultaneous recording of intraocular pressure (IOP and ocular pulse amplitude (OPA. It was the aim of this study to compare the IOP results of this new device with Goldmann tonometry. Furthermore, IOP and OPA measured with the new slitlamp-mounted DCT were compared to the IOP and OPA measured with the hand-held SmartLens®, a gonioscopic contact lens tonometer (ODC Ophthalmic Development Company AG, Switzerland. Methods Nineteen healthy subjects were included in this study. IOP was determined by three consecutive measurements with each of the DCT, SmartLens®, and Goldmann tonometer. Furthermore, OPA was measured three times consecutively by DCT and SmartLens®. Results No difference (P = 0.09 was found between the IOP values by means of DCT (mean: 16.6 mm Hg, median: 15.33 mm Hg, SD: +/- 4.04 mm Hg and Goldmann tonometry (mean: 16.17 mm Hg, median: 15.33 mm Hg, SD: +/- 4.03 mm Hg. The IOP values of SmartLens® (mean: 20.25 mm Hg, median: 19.00 mm Hg, SD: +/- 4.96 mm Hg were significantly higher (P = 0.0008 both from Goldmann tonometry and DCT. The OPA values of the DCT (mean: 3.08 mm Hg, SD: +/- 0.92 mm Hg were significantly lower (P = 0.0003 than those obtained by SmartLens® (mean: 3.92 mm Hg, SD: +/- 0.83 mm Hg. Conclusions DCT was equivalent to Goldmann applanation tonometry in measurement of IOP in a small group of normal subjects. In contrast, SmartLens® (contact lens tonometry gave IOP readings that were significantly higher compared with Goldmann applanation tonometer readings. Both devices, DCT and SmartLens® provide the measurement of OPA which could be helpful e.g. for the management of glaucoma.

  20. Machine Learning Techniques for Arterial Pressure Waveform Analysis

    Directory of Open Access Journals (Sweden)

    João Cardoso

    2013-05-01

    Full Text Available The Arterial Pressure Waveform (APW can provide essential information about arterial wall integrity and arterial stiffness. Most of APW analysis frameworks individually process each hemodynamic parameter and do not evaluate inter-dependencies in the overall pulse morphology. The key contribution of this work is the use of machine learning algorithms to deal with vectorized features extracted from APW. With this purpose, we follow a five-step evaluation methodology: (1 a custom-designed, non-invasive, electromechanical device was used in the data collection from 50 subjects; (2 the acquired position and amplitude of onset, Systolic Peak (SP, Point of Inflection (Pi and Dicrotic Wave (DW were used for the computation of some morphological attributes; (3 pre-processing work on the datasets was performed in order to reduce the number of input features and increase the model accuracy by selecting the most relevant ones; (4 classification of the dataset was carried out using four different machine learning algorithms: Random Forest, BayesNet (probabilistic, J48 (decision tree and RIPPER (rule-based induction; and (5 we evaluate the trained models, using the majority-voting system, comparatively to the respective calculated Augmentation Index (AIx. Classification algorithms have been proved to be efficient, in particular Random Forest has shown good accuracy (96.95% and high area under the curve (AUC of a Receiver Operating Characteristic (ROC curve (0.961. Finally, during validation tests, a correlation between high risk labels, retrieved from the multi-parametric approach, and positive AIx values was verified. This approach gives allowance for designing new hemodynamic morphology vectors and techniques for multiple APW analysis, thus improving the arterial pulse understanding, especially when compared to traditional single-parameter analysis, where the failure in one parameter measurement component, such as Pi, can jeopardize the whole evaluation.

  1. Kinetic analysis of pulsed laser induced phosphorescence for uranium determination

    International Nuclear Information System (INIS)

    Serdeiro, Nelida H.

    2003-01-01

    The laser induced kinetic phosphorescence allows the uranium determination in different kind of matrices, with a lower detection limit than those reached by other spectroscopic methods. It involves the uranyl ions excitation by a pulsed dye-laser source, followed by temporal resolution of the phosphorescence. This method is used for the determination of trace quantities of uranium in aqueous solution, with a suitable complexant agent, without chemical separation before the analysis. The objective of this paper is to present the results of uranium determinations in different standard samples, water, soil, filter and urine, and a comparison with other methods such as fluorimetry, alpha spectrometry and mass spectrometry. Moreover, the measurement conditions, the advantages and disadvantages, the sample preparation, the interferences and the detection limit are described. (author)

  2. Stroke volume variation compared with pulse pressure variation and cardiac index changes for prediction of fluid responsiveness in mechanically ventilated patients

    Directory of Open Access Journals (Sweden)

    Randa Aly Soliman

    2015-04-01

    Conclusions: Baseline stroke volume variation ⩾8.15% predicted fluid responsiveness in mechanically ventilated patients with acute circulatory failure. The study also confirmed the ability of pulse pressure variation to predict fluid responsiveness.

  3. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Mastwijk, H.C.; Knol, J.J.; Quataert, M.C.J.; Vervoort, L.; Plancken, van der I.; Hendrickx, M.E.; Matser, A.M.

    2011-01-01

    Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial

  4. Particle-in-cell simulations of multi-MeV pulsed X-ray induced air plasmas at low pressures

    International Nuclear Information System (INIS)

    Ribière, M.; D'Almeida, T.; Gaufridy de Dortan, F. de; Maulois, M.; Delbos, C.; Garrigues, A.; Cessenat, O.; Azaïs, B.

    2016-01-01

    A full kinetic modelling of the charge particles dynamics generated upon the irradiation of an air-filled cavity by a multi-MeV pulsed x-ray is performed. From the calculated radiative source generated by the ASTERIX generator, we calculated the electromagnetic fields generated by x-ray induced air plasmas in a metallic cavity at different pressures. Simulations are carried out based on a Particle-In-Cell interpolation method which uses 3D Maxwell-Vlasov calculations of the constitutive charged species densities of air plasmas at different pressures at equilibrium. The resulting electromagnetic fields within the cavity are calculated for different electron densities up to 4 × 10"1"0" cm"−"3. For each air pressure, we show electronic plasma waves formation followed by Landau damping. As electron density increases, the calculations exhibit space-charged neutralization and return current formation.

  5. Preparation of TiO sub 2 nanoparticles by pulsed laser ablation: Ambient pressure dependence of crystallization

    CERN Document Server

    Matsubara, M; Yamaki, T; Itoh, H; Abe, H

    2003-01-01

    Pulsed laser ablation (PLA) with a KrF excimer laser was used to prepare fine particles of titanium dioxide (TiO sub 2). The ablation in an atmosphere of Ar and O sub 2 (5:5) at total pressures of >= 1 Torr led to the formation of TiO sub 2 nanoparticles composed of anatase and rutile structures without any suboxides. The weight fraction of the rutile/anatase crystalline phases was dependent on the pressure of the Ar/O sub 2 gas. The TiO sub 2 nanoparticles had a spherical shape and their size, ranging from 10 and 14 nm, also appeared to be dependent on the ambient pressure. (author)

  6. Enhancement of laser-induced breakdown spectroscopy (LIBS) Detection limit using a low-pressure and short-pulse laser-induced plasma process.

    Science.gov (United States)

    Wang, Zhen Zhen; Deguchi, Yoshihiro; Kuwahara, Masakazu; Yan, Jun Jie; Liu, Ji Ping

    2013-11-01

    Laser-induced breakdown spectroscopy (LIBS) technology is an appealing technique compared with many other types of elemental analysis because of the fast response, high sensitivity, real-time, and noncontact features. One of the challenging targets of LIBS is the enhancement of the detection limit. In this study, the detection limit of gas-phase LIBS analysis has been improved by controlling the pressure and laser pulse width. In order to verify this method, low-pressure gas plasma was induced using nanosecond and picosecond lasers. The method was applied to the detection of Hg. The emission intensity ratio of the Hg atom to NO (IHg/INO) was analyzed to evaluate the LIBS detection limit because the NO emission (interference signal) was formed during the plasma generation and cooling process of N2 and O2 in the air. It was demonstrated that the enhancement of IHg/INO arose by decreasing the pressure to a few kilopascals, and the IHg/INO of the picosecond breakdown was always much higher than that of the nanosecond breakdown at low buffer gas pressure. Enhancement of IHg/INO increased more than 10 times at 700 Pa using picosecond laser with 35 ps pulse width. The detection limit was enhanced to 0.03 ppm (parts per million). We also saw that the spectra from the center and edge parts of plasma showed different features. Comparing the central spectra with the edge spectra, IHg/INO of the edge spectra was higher than that of the central spectra using the picosecond laser breakdown process.

  7. Thermo-mechanical analysis of the pressure plate of clutch

    Directory of Open Access Journals (Sweden)

    P.V.N. Venkata Mallikarjuna

    2017-09-01

    Full Text Available High Temperature appears in the contact surfaces of a clutch system (friction surface and pressure plate due to the relative motion between these parts during the sliding period. These high temperatures are responsible for several failures such as pressure plate crack, pressure plate warpage etc. With the help of Finite element analysis, the sliding friction process of the pressure plate and friction during clutch engagement is simulated to get temperature field characteristics and contact pressure of pressure plate.

  8. Determination of transport and reaction swarm coefficients from the analysis of complex transient pulses from the pulsed Townsend experiment

    International Nuclear Information System (INIS)

    Bekstein, A; De Urquijo, J; Rodríguez-Luna, J C; Juárez, A M; Ducasse, O

    2012-01-01

    We present in this paper the interpretation and analysis of transient pulses from a pulsed Townsend experiment by solving the continuity equations of the charged carriers (electrons and ions) involved in the avalanche. The set of second order partial differential equations is solved by SIMAV, a simulator designed specifically for the pulsed Townsend avalanche. Complex situations involving processes such as electron detachment, ion-molecule reactions, Penning ionization and secondary electron emission from ion impact at the cathode, virtually impossible to solve analytically, are discussed here to illustrate the capability of the simulator to help explain the various reaction processes involved in the avalanche, and also to derive some of the transport and reaction coefficients.

  9. Properties of gamma-ray burst time profiles using pulse decomposition analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.

    2000-02-08

    The time profiles of many gamma-ray bursts consist of distinct pulses, which offers the possibility of characterizing the temporal structure of these bursts using a relatively small set of pulse shape parameters. This pulse decomposition analysis has previously been performed on a small sample of bright long bursts using binned data from BATSE, which comes in several data types, and on a sample of short bursts using the BATSE Time-Tagged Event (TTE) data type. The authors have developed an interactive pulse-fitting program using the phenomenological pulse model of Norris, et. al. and a maximum-likelihood fitting routine. They have used this program to analyze the Time-to-Spill (TTS) data for all bursts observed by BATSE up through trigger number 2000, in all energy channels for which TTS data is available. They present statistical information on the attributes of pulses comprising these bursts, including relations between pulse characteristics through the course of a burst. They carry out simulations to determine the biases that their procedures may introduce. They find that pulses tend to have shorter rise times than decay times, and tend to be narrower and peak earlier at higher energies. They also find that pulse brightness, pulse width, and pulse hardness ratios do not evolve monotonically within bursts, but that the ratios of pulse rise times to decay times tends to decrease with time within bursts.

  10. Multi-Pulse Excitation for Underwater Analysis of Copper-Based Alloys Using a Novel Remote Laser-Induced Breakdown Spectroscopy (LIBS) System.

    Science.gov (United States)

    Guirado, Salvador; Fortes, Francisco J; Laserna, J Javier

    2016-04-01

    In this work, the use of multi-pulse excitation has been evaluated as an effective solution to mitigate the preferential ablation of the most volatile elements, namely Sn, Pb, and Zn, observed during laser-induced breakdown spectroscopy (LIBS) analysis of copper-based alloys. The novel remote LIBS prototype used in this experiments featured both single-pulse (SP-LIBS) and multi-pulse excitation (MP-LIBS). The remote instrument is capable of performing chemical analysis of submersed materials up to a depth of 50 m. Laser-induced breakdown spectroscopy analysis was performed at air pressure settings simulating the conditions during a real subsea analysis. A set of five certified bronze standards with variable concentration of Cu, As, Sn, Pb, and Zn were used. In SP-LIBS, signal emission is strongly sensitive to ambient pressure. In this case, fractionation effect was observed. Multi-pulse excitation circumvents the effect of pressure over the quantitative analysis, thus avoiding the fractionation phenomena observed in single pulse LIBS. The use of copper as internal standard minimizes matrix effects and discrepancies due to variation in ablated mass. © The Author(s) 2016.

  11. Variation in resistance of natural isolates of Staphylococcus aureus to heat, pulsed electric field and ultrasound under pressure.

    Science.gov (United States)

    Rodríguez-Calleja, J M; Cebrián, G; Condón, S; Mañas, P

    2006-05-01

    To study and compare the resistance of 15 Staphylococcus aureus isolates to heat, pulsed electric field (PEF) and ultrasound (UW) under pressure (manosonication, MS). Survival curves to heat (58 degrees C), to PEF (22 kV cm(-1), 2 micros square wave pulses) and to UW under pressure (117 microm, 20 kHz, 200 kPa) were obtained and inactivation parameters (decimal reduction times for heat and UW under pressure, and b-values for PEF) were calculated. A wide resistance variation to heat treatment, but not to PEF and MS, was observed amongst the 15 strains. There was no relationship between the resistances to the three physical agents studied. Staphylococcus aureus was relatively resistant to MS but sensitive to PEF. Heat resistance varied with strain and was positively correlated to carotenoid pigment content. Results would help in defining safe food preservation processes. Care should be taken to choose the most adequate strain of S. aureus to model food preservation processing.

  12. The flip-over effect in pulsed laser deposition: Is it relevant at high background gas pressures?

    Science.gov (United States)

    Ojeda-G-P, Alejandro; Schneider, Christof W.; Döbeli, Max; Lippert, Thomas; Wokaun, Alexander

    2015-12-01

    In pulsed laser deposition the use of a rectangular or elliptical beam spot with a non 1:1 aspect ratio leads to the so called flip-over effect. Here, the longest dimension of the laser spot results in the shortest direction of plasma plume expansion. This effect has been mainly reported for vacuum depositions of single element targets and is particularly noticeable when the aspect ratio of the beam spot is large. We investigate the flip-over effect in vacuum and at three relevant background-gas pressures for pulsed laser deposition using a La0.4Ca0.6MnO3 target by measuring the thickness dependence of the deposited material as a function of angle. The film thicknesses and compositions are determined by Rutherford backscattering and argon is used to reduce the influence of additional chemical reactions in the plasma. The results show the prevalence of the flip-over effect for all pressures except for the highest, i.e. 1 × 10-1 mbar, where the film thickness is constant for all angles. The composition profiles show noticeable compositional variations of up to 30% with respect to the target material depending on the background gas pressure, the angular location, and the laser spot dimensions.

  13. A comparison between the pathophysiology of multiple sclerosis and normal pressure hydrocephalus: is pulse wave encephalopathy a component of MS?

    Science.gov (United States)

    Bateman, Grant A; Lechner-Scott, Jeannette; Lea, Rodney A

    2016-09-22

    It has been suggested there is a chronic neurodegenerative disorder, underlying the pathophysiology of multiple sclerosis (MS), which is distinct from the more obvious immune-mediated attack on the white matter. Limited data exists indicating there is an alteration in pulse wave propagation within the craniospinal cavity in MS, similar to the findings in normal pressure hydrocephalus (NPH). It is hypothesized MS may harbor pulse wave encephalopathy. The purpose of this study is to compare blood flow and pulse wave measurements in MS patients with a cohort of NPH patients and control subjects, to test this hypothesis. Twenty patients with MS underwent magnetic resonance (MR) flow quantification techniques. Mean blood flow and stroke volume were measured in the arterial inflow and venous out flow from the sagittal (SSS) and straight sinus (ST). The arteriovenous delay (AVD) was defined. The results were compared with both age-matched controls and NPH patients. In MS there was a 35 % reduction in arteriovenous delay and a 5 % reduction in the percentage of the arterial inflow returning via the sagittal sinus compared to age matched controls. There was an alteration in pulse wave propagation, with a 26 % increase in arterial stroke volume but 30 % reduction in SSS and ST stroke volume. The AVD and blood flow changes were in the same direction to those of NPH patients. There are blood flow and pulsation propagation changes in MS patients which are similar to those of NPH patients. The findings would be consistent with an underlying pulse wave encephalopathy component in MS.

  14. Associations between body mass index, ambulatory blood pressure findings, and changes in cardiac structure: relevance of pulse and nighttime pressures.

    NARCIS (Netherlands)

    Fedecostante, M.; Spannella, F.; Giulietti, F.; Espinosa, E.; Dessi-Fulgheri, P.; Sarzani, R.

    2015-01-01

    Ambulatory blood pressure monitoring (ABPM) is central in the management of hypertension. Factors related to BP, such as body mass index (BMI), may differently affect particular aspects of 24-hour ABPM profiles. However, the relevance of BMI, the most used index of adiposity, has been

  15. The flip-over effect in pulsed laser deposition: Is it relevant at high background gas pressures?

    International Nuclear Information System (INIS)

    Ojeda-G-P, Alejandro; Schneider, Christof W.; Döbeli, Max; Lippert, Thomas; Wokaun, Alexander

    2015-01-01

    Highlights: • The flip-over effect in PLD is observed up to high deposition pressures. • Consistent congruent transfer of the target composition is generally not correct. • The choice of deposition pressure can change the film composition strongly. • Large compositional changes appear at high off-axis angles and large spot sizes. - Abstract: In pulsed laser deposition the use of a rectangular or elliptical beam spot with a non 1:1 aspect ratio leads to the so called flip-over effect. Here, the longest dimension of the laser spot results in the shortest direction of plasma plume expansion. This effect has been mainly reported for vacuum depositions of single element targets and is particularly noticeable when the aspect ratio of the beam spot is large. We investigate the flip-over effect in vacuum and at three relevant background-gas pressures for pulsed laser deposition using a La 0.4 Ca 0.6 MnO 3 target by measuring the thickness dependence of the deposited material as a function of angle. The film thicknesses and compositions are determined by Rutherford backscattering and argon is used to reduce the influence of additional chemical reactions in the plasma. The results show the prevalence of the flip-over effect for all pressures except for the highest, i.e. 1 × 10 −1 mbar, where the film thickness is constant for all angles. The composition profiles show noticeable compositional variations of up to 30% with respect to the target material depending on the background gas pressure, the angular location, and the laser spot dimensions.

  16. The flip-over effect in pulsed laser deposition: Is it relevant at high background gas pressures?

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda-G-P, Alejandro [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland); Schneider, Christof W., E-mail: christof.schneider@psi.ch [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland); Döbeli, Max [Ion Beam Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Lippert, Thomas; Wokaun, Alexander [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen-PSI (Switzerland)

    2015-12-01

    Highlights: • The flip-over effect in PLD is observed up to high deposition pressures. • Consistent congruent transfer of the target composition is generally not correct. • The choice of deposition pressure can change the film composition strongly. • Large compositional changes appear at high off-axis angles and large spot sizes. - Abstract: In pulsed laser deposition the use of a rectangular or elliptical beam spot with a non 1:1 aspect ratio leads to the so called flip-over effect. Here, the longest dimension of the laser spot results in the shortest direction of plasma plume expansion. This effect has been mainly reported for vacuum depositions of single element targets and is particularly noticeable when the aspect ratio of the beam spot is large. We investigate the flip-over effect in vacuum and at three relevant background-gas pressures for pulsed laser deposition using a La{sub 0.4}Ca{sub 0.6}MnO{sub 3} target by measuring the thickness dependence of the deposited material as a function of angle. The film thicknesses and compositions are determined by Rutherford backscattering and argon is used to reduce the influence of additional chemical reactions in the plasma. The results show the prevalence of the flip-over effect for all pressures except for the highest, i.e. 1 × 10{sup −1} mbar, where the film thickness is constant for all angles. The composition profiles show noticeable compositional variations of up to 30% with respect to the target material depending on the background gas pressure, the angular location, and the laser spot dimensions.

  17. Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness Gradient Not Affected by Mean Arterial Pressure.

    Science.gov (United States)

    Fortier, Catherine; Desjardins, Marie-Pier; Agharazii, Mohsen

    2018-03-01

    Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood pressure, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness gradient) as a blood pressure-independent measure of vascular aging. PWV is inherently dependent on the operational blood pressure. In cross-sectional studies, PWV adjustment for mean arterial pressure (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood pressure is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood pressure-independent stiffness parameter β (β 0 ) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood pressure-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood pressure-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness gradient, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness gradient, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP. The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness gradient

  18. Shape analysis of pulsed second sound in He II

    International Nuclear Information System (INIS)

    Worthington, T.; Yan, J.; Trefny, J.U.

    1976-01-01

    Second sound in He II has been observed using a heat pulse method. At temperatures where well-developed second sound is observed, the entire pulse shape can be understood if heat sources and geometrical effects are properly taken into account. 4 figures

  19. Design and application of pulse information acquisition and analysis ...

    African Journals Online (AJOL)

    ... two-dimensional information acquisition, multiplex signals combination and deep data mining. Conclusions: The newly developed system could translate the pulse signals into digital, visual and measurable motion information of vessel. Keywords: Visualized pulse information; Radial artery; B mode ultrasound; Traditional ...

  20. Approaches to the Optimal Nonlinear Analysis of Microcalorimeter Pulses

    Science.gov (United States)

    Fowler, J. W.; Pappas, C. G.; Alpert, B. K.; Doriese, W. B.; O'Neil, G. C.; Ullom, J. N.; Swetz, D. S.

    2018-03-01

    We consider how to analyze microcalorimeter pulses for quantities that are nonlinear in the data, while preserving the signal-to-noise advantages of linear optimal filtering. We successfully apply our chosen approach to compute the electrothermal feedback energy deficit (the "Joule energy") of a pulse, which has been proposed as a linear estimator of the deposited photon energy.

  1. Concerning the generation of very high pressures for EOS studies with ultra-high power laser pulses

    International Nuclear Information System (INIS)

    Wood, L.L.; Keeler, R.N.; Nuckolls, J.H.

    1977-07-01

    The use of basic physical and geometric principles, coupled with current laser technology, seems likely to extend experimental hyperbaric physics investigations from the megabar region into the portions of parameter space in which the ideal (degenerate) Fermi gas approximation is valid for even the highest Z materials. Implosions and speed-multiplying rectilinear stacks of flat plates seem particularly apt techniques for the near-term, transient attainment of pressure of 10 9 atmospheres in the laboratory, and laser-energized pulsed x-ray ''cameras'' appear suitable for analyzing the basic properties of matter under such conditions

  2. Biomarkers of inflammation and endothelial dysfunction as predictors of pulse pressure and incident hypertension in type 1 diabetes

    DEFF Research Database (Denmark)

    Ferreira, Isabel; Hovind, Peter; Schalkwijk, Casper G

    2018-01-01

    AIMS/HYPOTHESIS: Vascular inflammation and endothelial dysfunction are thought to contribute to arterial stiffening and hypertension. This study aims to test this hypothesis with longitudinal data in the context of type 1 diabetes. METHODS: We investigated, in an inception cohort of 277 individuals...... with type 1 diabetes, the course, tracking and temporal inter-relationships of BP, specifically pulse pressure (a marker of arterial stiffening) and hypertension, and the following biomarkers of systemic and vascular inflammation/endothelial dysfunction: C-reactive protein (CRP), soluble intracellular...... endothelial dysfunction and inflammation in the development of premature arterial stiffening and hypertension in type 1 diabetes....

  3. Cylinder Pressure-based Combustion Control with Multi-pulse Fuel Injection

    NARCIS (Netherlands)

    Luo, X.; Wang, S.; Jager, B. de; Willems, F.P.T.

    2015-01-01

    With an increased number of fuel injection pulses, the control problem in diesel engines becomes complex. Consisting of multiple single-input single-output (SISO) controllers, the conventional control strategy shows unsatisfactory dynamic performance in tracking combustion load and phase reference

  4. Elemental analysis using temporal gating of a pulsed neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Sudeep

    2018-02-20

    Technologies related to determining elemental composition of a sample that comprises fissile material are described herein. In a general embodiment, a pulsed neutron generator periodically emits bursts of neutrons, and is synchronized with an analyzer circuit. The bursts of neutrons are used to interrogate the sample, and the sample outputs gamma rays based upon the neutrons impacting the sample. A detector outputs pulses based upon the gamma rays impinging upon the material of the detector, and the analyzer circuit assigns the pulses to temporally-based bins based upon the analyzer circuit being synchronized with the pulsed neutron generator. A computing device outputs data that is indicative of elemental composition of the sample based upon the binned pulses.

  5. Method for detecting and distinguishing between specific types of environmental radiation using a high pressure ionization chamber with pulse-mode readout

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2017-12-19

    An environmental radiation detector for detecting and distinguishing between all types of environmental radiation, including photons, charged particles, and neutrons. A large volume high pressure ionization chamber (HPIC) includes BF.sub.3 gas at a specific concentration to render the radiation detector sensitive to the reactions of neutron capture in Boron-10 isotope. A pulse-mode readout is connected to the ionization chamber capable of measuring both the height and the width of the pulse. The heavy charged products of the neutron capture reaction deposit significant characteristic energy of the reaction in the immediate vicinity of the reaction in the gas, producing a signal with a pulse height proportional to the reaction energy, and a narrow pulse width corresponding to the essentially pointlike energy deposition in the gas. Readout of the pulse height and the pulse width parameters of the signals enables distinguishing between the different types of environmental radiation, such as gamma (x-rays), cosmic muons, and neutrons.

  6. Pulse Shape Analysis and Discrimination for Silicon-Photomultipliers in Helium-4 Gas Scintillation Neutron Detector

    Science.gov (United States)

    Barker, Cathleen; Zhu, Ting; Rolison, Lucas; Kiff, Scott; Jordan, Kelly; Enqvist, Andreas

    2018-01-01

    Using natural helium (helium-4), the Arktis 180-bar pressurized gas scintillator is capable of detecting and distinguishing fast neutrons and gammas. The detector has a unique design of three optically separated segments in which 12 silicon-photomultiplier (SiPM) pairs are positioned equilaterally across the detector to allow for them to be fully immersed in the helium-4 gas volume; consequently, no additional optical interfaces are necessary. The SiPM signals were amplified, shaped, and readout by an analog board; a 250 MHz, 14-bit digitizer was used to examine the output pulses from each SiPMpair channel. The SiPM over-voltage had to be adjusted in order to reduce pulse clipping and negative overshoot, which was observed for events with high scintillation production. Pulse shaped discrimination (PSD) was conducted by evaluating three different parameters: time over threshold (TOT), pulse amplitude, and pulse integral. In order to differentiate high and low energy events, a 30ns gate window was implemented to group pulses from two SiPM channels or more for the calculation of TOT. It was demonstrated that pulses from a single SiPM channel within the 30ns window corresponded to low-energy gamma events while groups of pulses from two-channels or more were most likely neutron events. Due to gamma pulses having lower pulse amplitude, the percentage of measured gamma also depends on the threshold value in TOT calculations. Similarly, the threshold values were varied for the optimal PSD methods of using pulse amplitude and pulse area parameters. Helium-4 detectors equipped with SiPMs are excellent for in-the-field radiation measurement of nuclear spent fuel casks. With optimized PSD methods, the goal of developing a fuel cask content monitoring and inspection system based on these helium-4 detectors will be achieved.

  7. A Quantitative Analysis of Pulsed Signals Emitted by Wild Bottlenose Dolphins.

    Directory of Open Access Journals (Sweden)

    Ana Rita Luís

    Full Text Available Common bottlenose dolphins (Tursiops truncatus, produce a wide variety of vocal emissions for communication and echolocation, of which the pulsed repertoire has been the most difficult to categorize. Packets of high repetition, broadband pulses are still largely reported under a general designation of burst-pulses, and traditional attempts to classify these emissions rely mainly in their aural characteristics and in graphical aspects of spectrograms. Here, we present a quantitative analysis of pulsed signals emitted by wild bottlenose dolphins, in the Sado estuary, Portugal (2011-2014, and test the reliability of a traditional classification approach. Acoustic parameters (minimum frequency, maximum frequency, peak frequency, duration, repetition rate and inter-click-interval were extracted from 930 pulsed signals, previously categorized using a traditional approach. Discriminant function analysis revealed a high reliability of the traditional classification approach (93.5% of pulsed signals were consistently assigned to their aurally based categories. According to the discriminant function analysis (Wilk's Λ = 0.11, F3, 2.41 = 282.75, P < 0.001, repetition rate is the feature that best enables the discrimination of different pulsed signals (structure coefficient = 0.98. Classification using hierarchical cluster analysis led to a similar categorization pattern: two main signal types with distinct magnitudes of repetition rate were clustered into five groups. The pulsed signals, here described, present significant differences in their time-frequency features, especially repetition rate (P < 0.001, inter-click-interval (P < 0.001 and duration (P < 0.001. We document the occurrence of a distinct signal type-short burst-pulses, and highlight the existence of a diverse repertoire of pulsed vocalizations emitted in graded sequences. The use of quantitative analysis of pulsed signals is essential to improve classifications and to better assess the

  8. Response Analysis on Electrical Pulses under Severe Nuclear Accident Temperature Conditions Using an Abnormal Signal Simulation Analysis Module

    Directory of Open Access Journals (Sweden)

    Kil-Mo Koo

    2012-01-01

    Full Text Available Unlike design basis accidents, some inherent uncertainties of the reliability of instrumentations are expected while subjected to harsh environments (e.g., high temperature and pressure, high humidity, and high radioactivity occurring in severe nuclear accident conditions. Even under such conditions, an electrical signal should be within its expected range so that some mitigating actions can be taken based on the signal in the control room. For example, an industrial process control standard requires that the normal signal level for pressure, flow, and resistance temperature detector sensors be in the range of 4~20 mA for most instruments. Whereas, in the case that an abnormal signal is expected from an instrument, such a signal should be refined through a signal validation process so that the refined signal could be available in the control room. For some abnormal signals expected under severe accident conditions, to date, diagnostics and response analysis have been evaluated with an equivalent circuit model of real instruments, which is regarded as the best method. The main objective of this paper is to introduce a program designed to implement a diagnostic and response analysis for equivalent circuit modeling. The program links signal analysis tool code to abnormal signal simulation engine code not only as a one body order system, but also as a part of functions of a PC-based ASSA (abnormal signal simulation analysis module developed to obtain a varying range of the R-C circuit elements in high temperature conditions. As a result, a special function for abnormal pulse signal patterns can be obtained through the program, which in turn makes it possible to analyze the abnormal output pulse signals through a response characteristic of a 4~20 mA circuit model and a range of the elements changing with temperature under an accident condition.

  9. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  10. Influence of oxygen pressure and aging on LaAlO3 films grown by pulsed laser deposition on SrTiO3 substrates

    KAUST Repository

    Park, Jihwey; Soh, Yeong-Ah; Aeppli, Gabriel; David, Adrian; Lin, Weinan; Wu, Tao

    2014-01-01

    The crystal structures of LaAlO3 films grown by pulsed laser deposition on SrTiO3 substrates at oxygen pressure of 10−3 millibars or 10−5 millibars, where kinetics of ablated species hardly depend on oxygen background pressure, are compared. Our

  11. Conformable Pressurized Structures : Design and Analysis

    NARCIS (Netherlands)

    Geuskens, F.J.J.M.M.

    2012-01-01

    There are many applications where volume needs to be pressurised within a geometrical space for which conventional pressure vessels do not provide suitable solutions. Applications are for example found in pressure cabins for Blended Wing Body Aircraft and conformable pressure vessels for an

  12. Pulse shape analysis optimization with segmented HPGe-detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, Lars; Birkenbach, Benedikt; Reiter, Peter [Institute for Nuclear Physics, University of Cologne (Germany); Bruyneel, Bart [CEA, Saclay (France); Collaboration: AGATA-Collaboration

    2014-07-01

    Measurements with the position sensitive, highly segmented AGATA HPGe detectors rely on the gamma-ray-tracking GRT technique which allows to determine the interaction point of the individual gamma-rays hitting the detector. GRT is based on a pulse shape analysis PSA of the preamplifier signals from the 36 segments and the central electrode of the detector. The achieved performance and position resolution of the AGATA detector is well within the specifications. However, an unexpected inhomogeneous distribution of interaction points inside the detector volume is observed as a result of the PSA even when the measurement is performed with an isotropically radiating gamma ray source. The clustering of interaction points motivated a study in order to optimize the PSA algorithm or its ingredients. Position resolution results were investigated by including contributions from differential crosstalk of the detector electronics, an improved preamplifier response function and a new time alignment. Moreover the spatial distribution is quantified by employing different χ{sup 2}-minimization procedures.

  13. Digital Double-Pulse Holographic Interferometry for Vibration Analysis

    Directory of Open Access Journals (Sweden)

    H.J. Tiziani

    1996-01-01

    Full Text Available Different arrangements for double-pulsed holographic and speckle interferometry for vibration analysis will be described. Experimental results obtained with films (classical holographic interferometry and CCD cameras (digital holographic interferometry as storage materials are presented. In digital holography, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and are stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation is obtained from the phase difference. In the case of electronic speckle pattern interferometry (or image plane hologram, the phase can be calculated by using the sinusoid-fitting method. In the case of digital holographic interferometry, the phase is obtained by digital reconstruction of the complex amplitudes of the wave fronts. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the 3-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed where a derotator needs to be used.

  14. Pulse shape analysis for germanium detectors used in DM searches

    International Nuclear Information System (INIS)

    Sagdeev, I.R.; Drukier, A.K.; Welsh, D.J.; Klimenko, A.A.; Osetrov, S.B.; Smolnikov, A.A.

    1994-01-01

    Progress in Ge detector technology has resulted in ultralow backgrounds of less than 0.3 countskeV -1 kg -1 d -1 at energies between 6 and 9keV and from 12 to 20keV. Between 4 and 6keV it is less than 2 countskeV -1 kg -1 d -1 . Coupled with good energy resolution, 0.4keV FWHM at 10keV, this allows searches for DM particles with m≥qslant8GeV/c 2 .Electromagnetic interference (EMI) and acoustical pick-up are the main sources of background in the best Ge detectors. A PC-based on-line pulse shape analysis system is presented which permits rejection of large fraction of the EMI/acoustical background. The hardware uses a low cost, commercially available digital storage oscilloscope (DSO). The software consists of about 40000 lines of code in Pascal and assembly language. We tested this system using a low radioactive background Ge-system at the Baksan observatory. For low energy events (<100keV) this system permits improvement in the background by about 20-30%. ((orig.))

  15. Characterization of Pressure Transients Generated by Nanosecond Electrical Pulse (nsEP) Exposure

    OpenAIRE

    Caleb C. Roth; Ronald A. Barnes Jr.; Bennett L. Ibey; Hope T. Beier; L. Christopher Mimun; Saher M. Maswadi; Mehdi Shadaram; Randolph D. Glickman

    2015-01-01

    The mechanism(s) responsible for the breakdown (nanoporation) of cell plasma membranes after nanosecond pulse (nsEP) exposure remains poorly understood. Current theories focus exclusively on the electrical field, citing electrostriction, water dipole alignment and/or electrodeformation as the primary mechanisms for pore formation. However, the delivery of a high-voltage nsEP to cells by tungsten electrodes creates a multitude of biophysical phenomena, including electrohydraulic cavitation, el...

  16. High count problems in elemental analysis using pulsed neutron inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Vartsky, D; Wielopolski, L; Ellis, K J; Cohn, S H [Brookhaven National Lab., Upton, NY (USA). Medical Dept.

    1983-03-01

    Elemental analysis by neutron inelastic scattering using a miniature intense pulsed neutron source ('Zetatron') was evaluated. The particular problems associated with detector pulse-pile-up during the neutron burst and the limited ability of the analyzer to process on average more than one detector pulse per neutron burst were examined. The severity of these problems is described and a solution using a multiple ADC system is proposed.

  17. Experimental and theoretical investigations on the dynamic response of EBR-II ducts under pressure pulse loading

    International Nuclear Information System (INIS)

    Chopra, P.S.; Srinivas, S.

    1975-01-01

    In order to assess the potential damage to hexagonal subassembly ducts (cans) that may result from rapid gas release from a failed element the EBR-II project has conducted experiments and analyses. Additional experimental and analytical investigations are now being conducted to assure fail-safety of the ducts. Fail-safety is defined as the ability of a duct to withstand pressure pulses from failed elements during all reactor conditions without damage to adjacent ducts or any other problems in fuel handling. The results of 93 EBR-II duct tests conducted primarily by Koenig have been reported previously. The results of empirical correlations of some of these tests to determine the influence of several variables on the pressure pulse experienced by a duct and on the duct deformation are presented. The variables include the type of gas contained in the simulated element (tube), the element and duct materials, the presence or absence of flow restrictors in the element, and the way gas was released. 8 references. (auth)

  18. Threshold value of home pulse pressure predicting arterial stiffness in patients with type 2 diabetes: KAMOGAWA-HBP study.

    Science.gov (United States)

    Kitagawa, Noriyuki; Ushigome, Emi; Matsumoto, Shinobu; Oyabu, Chikako; Ushigome, Hidetaka; Yokota, Isao; Asano, Mai; Tanaka, Muhei; Yamazaki, Masahiro; Fukui, Michiaki

    2018-03-01

    This cross-sectional multicenter study was designed to evaluate the threshold value of home pulse pressure (PP) and home systolic blood pressure (SBP) predicting the arterial stiffness in 876 patients with type 2 diabetes. We measured the area under the receiver-operating characteristic curve (AUC) and estimated the ability of home PP to identify arterial stiffness using Youden-Index defined cut-off point. The arterial stiffness was measured using the brachial-ankle pulse wave velocity (baPWV). AUC for arterial stiffness in morning PP was significantly greater than that in morning SBP (P AUC for arterial stiffness in evening PP was also significantly greater than that in evening SBP (P < .001). The optimal cut-off points for morning PP and evening PP, which predicted arterial stiffness, were 54.6 and 56.9 mm Hg, respectively. Our findings indicate that we should pay more attention to increased home PP in patients with type 2 diabetes. ©2018 Wiley Periodicals, Inc.

  19. a comparative analysis of the rebound hammer and ultrasonic pulse

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... properties of concrete for quality assurance and for evaluation of existing conditions. Since such test are expected not to impair the function of .... Receiver. Amplifier. Time Display. Unit. Receiving Transducer. Pulse. Generator.

  20. Continuous cuff-less blood pressure monitoring based on the pulse arrival time approach: the impact of posture.

    Science.gov (United States)

    Muehlsteff, J; Aubert, X A; Morren, G

    2008-01-01

    There is an unmet need for cuff-less blood pressure (BP) monitoring especially, in personal healthcare applications. The pulse arrival time (PAT) approach might offer a suitable solution to enable comfortable BP monitoring even at beat-level. However, the methodology is based on hemodynamic surrogate measures, which are sensitive to patient activities such as posture changes, not necessarily related to blood pressure variations. In this paper, we analyze the impact of posture on the PAT measure and related hemodynamic parameters such as the pre-ejection period in well-defined procedures. Additionally, the PAT of a monitored subject is investigated in an unsupervised scenario illustrating the complexity of such a measurement. Our results show the failure of blood pressure inference based on simple calibration strategies using the PAT measure only. We discuss opportunities to compensate for the observed effects towards the realization of wearable cuff-less blood pressure monitoring. These findings emphasize the importance of accessing context information in personal healthcare applications, where vital sign monitoring is typically unsupervised.

  1. Analysis of pulsed injection for microgravity receiver tank chilldown

    Science.gov (United States)

    Honkonen, Scott C.; Pietrzyk, Joe R.; Schuster, John R.

    The dominant heat transfer mechanism during the hold phase of a tank chilldown cycle in a low-gravity environment is due to fluid motion persistence following the charge. As compared to the single-charge per vent cycle case, pulsed injection maintains fluid motion and the associated high wall heat transfer coefficients during the hold phase. As a result, the pulsed injection procedure appears to be an attractive method for reducing the time and liquid mass required to chill a tank. However, for the representative conditions considered, no significant benefit can be realized by using pulsed injection as compared to the single-charge case. A numerical model of the charge/hold/vent process was used to evaluate the pulsed injection procedure for tank chilldown in microgravity. Pulsed injection results in higher average wall heat transfer coefficients during the hold, as compared to the single-charge case. However, these high levels were not coincident with the maximum wall-to-fluid temperature differences, as in the single-charge case. For representative conditions investigated, the charge/hold/vent process is very efficient. A slightly shorter chilldown time was realized by increasing the number of pulses.

  2. Autonomic Nervous System Responses to Concussion: Arterial Pulse Contour Analysis

    Directory of Open Access Journals (Sweden)

    Michael F La Fountaine

    2016-02-01

    Full Text Available The arterial pulse wave (APW has a distinct morphology whose contours reflect dynamics in cardiac function and peripheral vascular tone as a result of sympathetic nervous system (SNS control. With a transition from rest to increased metabolic demand, the expected augmentation of SNS outflow will not only affect arterial blood pressure and heart rate, it will also induce changes to the contours of the APW. Following a sports concussion, a transient state cardiovascular autonomic dysfunction is present. How this state affects the APW, has yet to be described. A prospective, parallel-group study on cardiovascular autonomic control (i.e., digital electrocardiogram and continuous beat-to-beat blood pressure was performed in the seated upright position in ten athletes with concussion and 7 non-injured control athletes. Changes in APW were compared at rest and during the first 60 seconds (F60 of an isometric handgrip test (IHGT in concussed athletes and non-injured controls within 48 hours (48hr and 1 week (1wk of injury. The concussion group was further separated by the length of time until they were permitted to return to play (RTP>1wk; RTP≤1wk. SysSlope, an indirect measurement of stroke volume, was significantly lower in the concussion group at rest and during F60 at 48hr and 1wk; a paradoxical decline in SysSlope occurred at each visit during the transition from rest to IHGT F60. The RTP>1wk group had lower SysSlope (405±200; 420±88; 454±236 mmHg/s, respectively at rest 48hr compared to the RTP≤1wk and controls. Similarly at 48hr rest, several measurements of arterial stiffness were abnormal in RTP>1wk compared to RTP≤1wk and controls: Peak-to-Notch Latency (0.12±0.04; 0.16±0.02; 0.17±0.05, respectively, Notch Relative Amplitude (0.70±0.03; 0.71±0.04; 0.66±0.14, respectively and Stiffness Index (6.4±0.2; 5.7±0.4; 5.8±0.5, respectively. Use of APW revealed that concussed athletes have a transient increase in peripheral artery

  3. Pulse Rate and Transit Time Analysis to Predict Hypotension Events After Spinal Anesthesia During Programmed Cesarean Labor.

    Science.gov (United States)

    Bolea, Juan; Lázaro, Jesús; Gil, Eduardo; Rovira, Eva; Remartínez, José M; Laguna, Pablo; Pueyo, Esther; Navarro, Augusto; Bailón, Raquel

    2017-09-01

    Prophylactic treatment has been proved to reduce hypotension incidence after spinal anesthesia during cesarean labor. However, the use of pharmacological prophylaxis could carry out undesirable side-effects on mother and fetus. Thus, the prediction of hypotension becomes an important challenge. Hypotension events are hypothesized to be related to a malfunctioning of autonomic nervous system (ANS) regulation of blood pressure. In this work, ANS responses to positional changes of 51 pregnant women programmed for a cesarean labor were explored for hypotension prediction. Lateral and supine decubitus, and sitting position were considered while electrocardiographic and pulse photoplethysmographic signals were recorded. Features based on heart rate variability, pulse rate variability (PRV) and pulse transit time (PTT) analysis were used in a logistic regression classifier. The results showed that PRV irregularity changes, assessed by approximate entropy, from supine to lateral decubitus, and standard deviation of PTT in supine decubitus were found as the combination of features that achieved the best classification results sensitivity of 76%, specificity of 70% and accuracy of 72%, being normotensive the positive class. Peripheral regulation and blood pressure changes, measured by PRV and PTT analysis, could help to predict hypotension events reducing prophylactic side-effects in the low-risk population.

  4. Cardiac output by pulse contour analysis does not match the increase measured by rebreathing during human spaceflight.

    Science.gov (United States)

    Hughson, Richard L; Peterson, Sean D; Yee, Nicholas J; Greaves, Danielle K

    2017-11-01

    Pulse contour analysis of the noninvasive finger arterial pressure waveform provides a convenient means to estimate cardiac output (Q̇). The method has been compared with standard methods under a range of conditions but never before during spaceflight. We compared pulse contour analysis with the Modelflow algorithm to estimates of Q̇ obtained by rebreathing during preflight baseline testing and during the final month of long-duration spaceflight in nine healthy male astronauts. By Modelflow analysis, stroke volume was greater in supine baseline than seated baseline or inflight. Heart rate was reduced in supine baseline so that there were no differences in Q̇ by Modelflow estimate between the supine (7.02 ± 1.31 l/min, means ± SD), seated (6.60 ± 1.95 l/min), or inflight (5.91 ± 1.15 l/min) conditions. In contrast, rebreathing estimates of Q̇ increased from seated baseline (4.76 ± 0.67 l/min) to inflight (7.00 ± 1.39 l/min, significant interaction effect of method and spaceflight, P < 0.001). Pulse contour analysis utilizes a three-element Windkessel model that incorporates parameters dependent on aortic pressure-area relationships that are assumed to represent the entire circulation. We propose that a large increase in vascular compliance in the splanchnic circulation invalidates the model under conditions of spaceflight. Future spaceflight research measuring cardiac function needs to consider this important limitation for assessing absolute values of Q̇ and stroke volume. NEW & NOTEWORTHY Noninvasive assessment of cardiac function during human spaceflight is an important tool to monitor astronaut health. This study demonstrated that pulse contour analysis of finger arterial blood pressure to estimate cardiac output failed to track the 46% increase measured by a rebreathing method. These results strongly suggest that alternative methods not dependent on pulse contour analysis are required to track cardiac function in spaceflight

  5. Statistical analysis of silo wall pressures

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Berntsen, Kasper Nikolaj

    1998-01-01

    Previously published silo wall pressure measurements during plug flow of barley in alarge concrete silo are re-analysed under the hypothesis that the wall pressures are gamma-distributed.The fits of the gamma distribution type to the local pressure data from each measuring cell are satisfactory.......However, the estimated parameters of the gamma distributions turn out to be significantly inhomogeneous overthe silo wall surface. This inhomogeneity is attributed to the geometrical imperfections of the silo wall.Motivated by the engineering importance of the problem a mathematical model for constructing astochastic...... gamma-type continuous pressure field is given. The model obeys the necessary equilibrium conditionsof the wall pressure field and reflects the spatial correlation properties as estimated from simultaneouslymeasured pressures at different locations along a horizontal perimeter....

  6. Prenatal exposure to dexamethasone in the mouse alters cardiac growth patterns and increases pulse pressure in aged male offspring.

    Directory of Open Access Journals (Sweden)

    Lee O'Sullivan

    Full Text Available Exposure to synthetic glucocorticoids during development can result in later cardiovascular and renal disease in sheep and rats. Although prenatal glucocorticoid exposure is associated with impaired renal development, less is known about effects on the developing heart. This study aimed to examine the effects of a short-term exposure to dexamethasone (60 hours from embryonic day 12.5 on the developing mouse heart, and cardiovascular function in adult male offspring. Dexamethasone (DEX exposed fetuses were growth restricted compared to saline treated controls (SAL at E14.5, but there was no difference between groups at E17.5. Heart weights of the DEX fetuses also tended to be smaller at E14.5, but not different at E17.5. Cardiac AT1aR, Bax, and IGF-1 mRNA expression was significantly increased by DEX compared to SAL at E17.5. In 12-month-old offspring DEX exposure caused an increase in basal blood pressure of ~3 mmHg. In addition, DEX exposed mice had a widened pulse pressure compared to SAL. DEX exposed males at 12 months had an approximate 25% reduction in nephron number compared to SAL, but no difference in cardiomyocyte number. Exposure to DEX in utero appears to adversely impact on nephrogenesis and heart growth but is not associated with a cardiomyocyte deficit in male mice in adulthood, possibly due to compensatory growth of the myocardium following the initial insult. However, the widened pulse pressure may be indicative of altered vascular compliance.

  7. Estimating Hydraulic Conductivities in a Fractured Shale Formation from Pressure Pulse Testing and 3d Modeling

    Science.gov (United States)

    Courbet, C.; DICK, P.; Lefevre, M.; Wittebroodt, C.; Matray, J.; Barnichon, J.

    2013-12-01

    In the framework of its research on the deep disposal of radioactive waste in shale formations, the French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a large array of in situ programs concerning the confining properties of shales in their underground research laboratory at Tournemire (SW France). One of its aims is to evaluate the occurrence and processes controlling radionuclide migration through the host rock, from the disposal system to the biosphere. Past research programs carried out at Tournemire covered mechanical, hydro-mechanical and physico-chemical properties of the Tournemire shale as well as water chemistry and long-term behaviour of the host rock. Studies show that fluid circulations in the undisturbed matrix are very slow (hydraulic conductivity of 10-14 to 10-15 m.s-1). However, recent work related to the occurrence of small scale fractures and clay-rich fault gouges indicate that fluid circulations may have been significantly modified in the vicinity of such features. To assess the transport properties associated with such faults, IRSN designed a series of in situ and laboratory experiments to evaluate the contribution of both diffusive and advective process on water and solute flux through a clay-rich fault zone (fault core and damaged zone) and in an undisturbed shale formation. As part of these studies, Modular Mini-Packer System (MMPS) hydraulic testing was conducted in multiple boreholes to characterize hydraulic conductivities within the formation. Pressure data collected during the hydraulic tests were analyzed using the nSIGHTS (n-dimensional Statistical Inverse Graphical Hydraulic Test Simulator) code to estimate hydraulic conductivity and formation pressures of the tested intervals. Preliminary results indicate hydraulic conductivities of 5.10-12 m.s-1 in the fault core and damaged zone and 10-14 m.s-1 in the adjacent undisturbed shale. Furthermore, when compared with neutron porosity data from borehole

  8. Soft error rate analysis methodology of multi-Pulse-single-event transients

    International Nuclear Information System (INIS)

    Zhou Bin; Huo Mingxue; Xiao Liyi

    2012-01-01

    As transistor feature size scales down, soft errors in combinational logic because of high-energy particle radiation is gaining more and more concerns. In this paper, a combinational logic soft error analysis methodology considering multi-pulse-single-event transients (MPSETs) and re-convergence with multi transient pulses is proposed. In the proposed approach, the voltage pulse produced at the standard cell output is approximated by a triangle waveform, and characterized by three parameters: pulse width, the transition time of the first edge, and the transition time of the second edge. As for the pulse with the amplitude being smaller than the supply voltage, the edge extension technique is proposed. Moreover, an efficient electrical masking model comprehensively considering transition time, delay, width and amplitude is proposed, and an approach using the transition times of two edges and pulse width to compute the amplitude of pulse is proposed. Finally, our proposed firstly-independently-propagating-secondly-mutually-interacting (FIP-SMI) is used to deal with more practical re-convergence gate with multi transient pulses. As for MPSETs, a random generation model of MPSETs is exploratively proposed. Compared to the estimates obtained using circuit level simulations by HSpice, our proposed soft error rate analysis algorithm has 10% errors in SER estimation with speed up of 300 when the single-pulse-single-event transient (SPSET) is considered. We have also demonstrated the runtime and SER decrease with the increment of P0 using designs from the ISCAS-85 benchmarks. (authors)

  9. Simultaneous hit finding and timing method for pulse shape analysis of drift chamber signals

    Energy Technology Data Exchange (ETDEWEB)

    Schaile, D; Schaile, O; Schwarz, J

    1986-01-01

    An algorithm for the analysis of the digitized signal waveform of drift chamber pulses is described which yields a good multihit resolution and an accurate drift time determination with little processing time. The method has been tested and evaluated with measured pulse shapes from the full size prototype of the OPAL central detector which were digitized by 100 MHz FADCs. (orig.).

  10. Simultaneous hit finding and timing method for pulse shape analysis of drift chamber signals

    Energy Technology Data Exchange (ETDEWEB)

    Schaile, D; Schaile, O; Schwarz, J

    1986-01-01

    An algorithm for the analysis of the digitized signal waveform of drift chamber pulses is described which yields a good multihit resolution and an accurate drift time determination with little processing time. The method has been tested and evaluated with measured pulse shapes from the full size prototype of the OPAL central detector which were digitized by 100 MHz FADCs.

  11. Pressure Distribution on Inner Wall of Parabolic Nozzle in Laser Propulsion with Single Pulse

    Science.gov (United States)

    Cui, Cunyan; Hong, Yanji; Wen, Ming; Song, Junling; Fang, Juan

    2011-11-01

    A system based of dynamic pressure sensors was established to study the time resolved pressure distribution on the inner wall of a parabolic nozzle in laser propulsion. Dynamic calibration and static calibration of the test system were made and the results showed that frequency response was up to 412 kHz and linear error was less than 10%. Experimental model was a parabolic nozzle and three test points were preset along one generating line. This study showed that experimental results agreed well with those obtained by numerical calculation way in pressure evolution tendency. The peak value of the calculation was higher than that of the experiment at each tested orifice because of the limitation of the numerical models. The results of this study were very useful for analyzing the energy deposition in laser propulsion and modifying numerical models.

  12. Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... transducer model and the FIELD II software in combination give good agreement with measurements....

  13. Low-intensity pulsed ultrasound enhances angiogenesis and ameliorates contractile dysfunction of pressure-overloaded heart in mice.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Ogata

    Full Text Available Chronic left ventricular (LV pressure overload causes relative ischemia with resultant LV dysfunction. We have recently demonstrated that low-intensity pulsed ultrasound (LIPUS improves myocardial ischemia in a pig model of chronic myocardial ischemia through enhanced myocardial angiogenesis. In the present study, we thus examined whether LIPUS also ameliorates contractile dysfunction in LV pressure-overloaded hearts.Chronic LV pressure overload was induced with transverse aortic constriction (TAC in mice. LIPUS was applied to the whole heart three times in the first week after TAC and was repeated once a week for 7 weeks thereafter (n = 22. Animals in the control groups received the sham treatment without LIPUS (n = 23. At 8 weeks after TAC, LV fractional shortening was depressed in the TAC-Control group, which was significantly ameliorated in the TAC-LIPUS group (30.4±0.5 vs. 36.2±3.8%, P<0.05. Capillary density was higher and perivascular fibrosis was less in the LV in the TAC-LIPUS group than in the TAC-Control group. Myocardial relative ischemia evaluated with hypoxyprobe was noted in the TAC-Control group, which was significantly attenuated in the TAC-LIPUS group. In the TAC-LIPUS group, as compared with the control group, mRNA expressions of BNP and collagen III were significantly lower (both P<0.05 and protein expressions of VEGF and eNOS were significantly up-regulated associated with Akt activation (all P<0.05. No adverse effect related to the LIPUS therapy was noted.These results indicate that the LIPUS therapy ameliorates contractile dysfunction in chronically pressure-overloaded hearts through enhanced myocardial angiogenesis and attenuated perivascular fibrosis. Thus, the LIPUS therapy may be a promising, non-invasive treatment for cardiac dysfunction due to chronic pressure overload.

  14. Comparison of the Complior Analyse device with Sphygmocor and Complior SP for pulse wave velocity and central pressure assessment.

    Science.gov (United States)

    Stea, Francesco; Bozec, Erwan; Millasseau, Sandrine; Khettab, Hakim; Boutouyrie, Pierre; Laurent, Stéphane

    2014-04-01

    The Complior device (Alam Medical, France) was used in epidemiological studies which established pulse wave velocity (PWV) as a cardiovascular risk marker. Central pressure is related, but complementary to PWV and also associated to cardiovascular outcomes. The new Complior Analyse measures both PWV and central blood pressure during the same acquisition. The aim of this study was to compare PWV values from Complior Analyse with the previous Complior SP (PWVcs) and with Sphygmocor (PWVscr; AtCor, Australia), and to compare central systolic pressure from Complior Analyse and Sphygmocor. Peripheral and central pressures and PWV were measured with the three devices in 112 patients. PWV measurements from Complior Analyse were analysed using two foot-detection algorithms (PWVca_it and PWVca_cs). Both radial (ao-SBPscr) and carotid (car-SBPscr) approaches from Sphygmocor were compared to carotid Complior Analyse measurements (car-SBPca). The same distance and same calibrating pressures were used for all devices. PWVca_it was strongly correlated to PWVscr (R(2) = 0.93, P < 0.001) with a difference of 0.0 ± 0.7  m/s. PWVca_cs was also correlated to PWVcs (R(2) = 0.90, P < 0.001) with a difference of 0.1 ± 0.7  m/s. Central systolic pressures were strongly correlated. The difference between car-SBPca and ao-SBPscr was 3.1 ± 4.2  mmHg (P < 0.001), statistically equivalent to the difference between car-SBPscr and ao-SBPscr (3.9 ± 5.8  mmHg, P < 0.001), whilst the difference between car-SBPca and car-SBPscr was negligible (-0.7 ± 5.6  mmHg, P = NS). The new Complior Analyse device provides equivalent results for PWV and central pressure values to the Sphygmocor and Complior SP. It reaches Association for the Advancement of Medical Instrumentation standard for central blood pressure and grades as excellent for PWV on the Artery Society criteria. It can be interchanged with existing devices.

  15. Reliability of pulse waveform separation analysis: effects of posture and fasting.

    Science.gov (United States)

    Stoner, Lee; Credeur, Daniel; Fryer, Simon; Faulkner, James; Lambrick, Danielle; Gibbs, Bethany Barone

    2017-03-01

    Oscillometric pulse wave analysis devices enable, with relative simplicity and objectivity, the measurement of central hemodynamic parameters. The important parameters are central blood pressures and indices of arterial wave reflection, including wave separation analysis (backward pressure component Pb and reflection magnitude). This study sought to determine whether the measurement precision (between-day reliability) of Pb and reflection magnitude: exceeds the criterion for acceptable reliability; and is affected by posture (supine, seated) and fasting state. Twenty healthy adults (50% female, 27.9 years, 24.2 kg/m) were tested on six different mornings: 3 days fasted, 3 days nonfasted condition. On each occasion, participants were tested in supine and seated postures. Oscillometric pressure waveforms were recorded on the left upper arm. The criterion intra-class correlation coefficient value of 0.75 was exceeded for Pb (0.76) and reflection magnitude (0.77) when participants were assessed under the combined supine-fasted condition. The intra-class correlation coefficient was lowest for Pb in seated-nonfasted condition (0.57), and lowest for reflection magnitude in the seated-fasted condition (0.56). For Pb, the smallest detectible change that must be exceeded in order for a significant change to occur in an individual was 2.5 mmHg, and for reflection magnitude, the smallest detectable change was 8.5%. Assessments of Pb and reflection magnitude are as follows: exceed the criterion for acceptable reliability; and are most reliable when participants are fasted in a supine position. The demonstrated reliability suggests sufficient precision to detect clinically meaningful changes in reflection magnitude and Pb.

  16. Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

    DEFF Research Database (Denmark)

    Schytz, Philip Andreas; Mace, Maria Lerche; Soja, Anne Merete Boas

    2015-01-01

    BACKGROUND: If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect...

  17. Transient effects caused by pulsed gas and liquid injections into low pressure plasmas

    International Nuclear Information System (INIS)

    Ogawa, D; Goeckner, M; Overzet, L; Chung, C W

    2010-01-01

    The fast injection of liquid droplets into a glow discharge causes significant time variations in the pressure, the chemical composition of the gas and the phases present (liquid and/or solid along with gas). While the variations can be large and important, very few studies, especially kinetic studies, have been published. In this paper we examine the changes brought about in argon plasma by injecting Ar (gas), N 2 (gas) hexane (gas) and hexane (liquid droplets). The changes in the RF capacitively coupled power (forward and reflected), electron and ion density (n e , n i ), electron temperature (T e ) and optical emissions were monitored during the injections. It was found that the Ar injection (pressure change only) caused expected variations. The electron temperature reduced, the plasma density increased and the optical emission intensity remained nearly constant. The N 2 and hexane gas injections (chemical composition and pressure changes) also followed expected trends. The plasma densities increased and electron temperature decreased while the optical emissions changed from argon to the injected gas. These all serve to highlight the fact that the injection of evaporating hexane droplets in the plasma caused very little change. This is because the number of injected droplets is too small to noticeably affect the plasma, even though the shift in the chemical composition of the gas caused by evaporation from those same droplets can be very significant. The net conclusion is that using liquid droplets to inject precursors for low pressure plasmas is both feasible and controllable.

  18. Pressurizer pump reliability analysis high flux isotope reactor

    International Nuclear Information System (INIS)

    Merryman, L.; Christie, B.

    1993-01-01

    During a prolonged outage from November 1986 to May 1990, numerous changes were made at the High Flux Isotope Reactor (HFIR). Some of these changes involved the pressurizer pumps. An analysis was performed to calculate the impact of these changes on the pressurizer system availability. The analysis showed that the availability of the pressurizer system dropped from essentially 100% to approximately 96%. The primary reason for the decrease in availability comes because off-site power grid disturbances sometimes result in a reactor trip with the present pressurizer pump configuration. Changes are being made to the present pressurizer pump configuration to regain some of the lost availability

  19. Simulation of subnanosecond streamers in atmospheric-pressure air: Effects of polarity of applied voltage pulse

    Energy Technology Data Exchange (ETDEWEB)

    Babaeva, N. Yu.; Naidis, G. V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation)

    2016-08-15

    Results of simulation of subnanosecond streamer propagation in corona gap configuration, obtained in the framework of 2D fluid model, are presented. Effects related with the polarity of a voltage pulse applied to the stressed electrode are discussed. It is argued that these effects (dependence of the discharge current and propagation velocity on the polarity of applied voltage) observed in experiments can be attributed to the difference in initial (preceding the streamer formation) distributions of charged species inside the gap. This difference can be caused by preionization (at negative polarity) of the gas inside the discharge gap by runaway electrons. Calculated streamers have large widths (up to 1 cm) and move with velocities in the range of 10{sup 9}–10{sup 10 }cm s{sup −1}, similar to experimental data.

  20. Highly sensitive analysis of boron and lithium in aqueous solution using dual-pulse laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Lee, Dong-Hyoung; Han, Sol-Chan; Kim, Tae-Hyeong; Yun, Jong-Il

    2011-12-15

    We have applied a dual-pulse laser-induced breakdown spectroscopy (DP-LIBS) to sensitively detect concentrations of boron and lithium in aqueous solution. Sequential laser pulses from two separate Q-switched Nd:YAG lasers at 532 nm wavelength have been employed to generate laser-induced plasma on a water jet. For achieving sensitive elemental detection, the optimal timing between two laser pulses was investigated. The optimum time delay between two laser pulses for the B atomic emission lines was found to be less than 3 μs and approximately 10 μs for the Li atomic emission line. Under these optimized conditions, the detection limit was attained in the range of 0.8 ppm for boron and 0.8 ppb for lithium. In particular, the sensitivity for detecting boron by excitation of laminar liquid jet was found to be excellent by nearly 2 orders of magnitude compared with 80 ppm reported in the literature. These sensitivities of laser-induced breakdown spectroscopy are very practical for the online elemental analysis of boric acid and lithium hydroxide serving as neutron absorber and pH controller in the primary coolant water of pressurized water reactors, respectively.

  1. Fracture analysis of axially cracked pressure tube of pressurized heavy water reactor

    International Nuclear Information System (INIS)

    Krishnan, S.; Bhasin, V.; Mahajan, S.C.

    1997-01-01

    Three Dimensional (313) finite element elastic plastic fracture analysis was done for through wall axially cracked thin pressure tubes of 220 MWe Indian Pressurized Heavy Water Reactor. The analysis was done for Zr-2 and Zr-2.5Nb pressure tubes operating at 300 degrees C and subjected to 9.5 Mpa internal pressure. Critical crack length was determined based on tearing instability concept. The analysis included the effect of crack face pressure due to the leaking fluid from tube. This effect was found to be significant for pressure tubes. The available formulae for calculating J (for axially cracked tubes) do not take into account the effect of crack face pressure. 3D finite element analysis also gives insight into variation of J across the thickness of pressure tube. It was observed that J is highest at the mid-surface of tube. The results have been presented in the form of across the thickness average J value and a peak factor on J. Peak factor on J is ratio of J at mid surface to average J value. Crack opening area for different cracked lengths was calculated from finite element results. The fracture assessment of pressure tubes was also done using Central Electricity Generating Board R-6 method. Ductile tearing was considered

  2. Fracture analysis of axially cracked pressure tube of pressurized heavy water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, S.; Bhasin, V.; Mahajan, S.C. [Bhabha Atomic Research Centre, Bombay (India)] [and others

    1997-04-01

    Three Dimensional (313) finite element elastic plastic fracture analysis was done for through wall axially cracked thin pressure tubes of 220 MWe Indian Pressurized Heavy Water Reactor. The analysis was done for Zr-2 and Zr-2.5Nb pressure tubes operating at 300{degrees}C and subjected to 9.5 Mpa internal pressure. Critical crack length was determined based on tearing instability concept. The analysis included the effect of crack face pressure due to the leaking fluid from tube. This effect was found to be significant for pressure tubes. The available formulae for calculating J (for axially cracked tubes) do not take into account the effect of crack face pressure. 3D finite element analysis also gives insight into variation of J across the thickness of pressure tube. It was observed that J is highest at the mid-surface of tube. The results have been presented in the form of across the thickness average J value and a peak factor on J. Peak factor on J is ratio of J at mid surface to average J value. Crack opening area for different cracked lengths was calculated from finite element results. The fracture assessment of pressure tubes was also done using Central Electricity Generating Board R-6 method. Ductile tearing was considered.

  3. Reference values and associated factors for Japanese newborns' blood pressure and pulse rate: the babies' and their parents' longitudinal observation in Suzuki Memorial Hospital on intrauterine period (BOSHI) study.

    Science.gov (United States)

    Satoh, Michihiro; Inoue, Ryusuke; Tada, Hideko; Hosaka, Miki; Metoki, Hirohito; Asayama, Kei; Murakami, Takahisa; Mano, Nariyasu; Ohkubo, Takayoshi; Yagihashi, Katsuyo; Hoshi, Kazuhiko; Suzuki, Masakuni; Imai, Yutaka

    2016-08-01

    Currently, normative means and ranges of blood pressure (BP) and pulse rates in Japanese newborns are not available. The objective of the present study was to estimate BP, pulse rate, and their distribution among Japanese newborns. Using oscillometric devices, arm or calf BP and pulse rate levels were obtained from 3148 infants born between 2007 and 2014, consecutively at Suzuki Memorial Hospital, Iwanuma, Japan. Of those, data from 2628 full-term, singleton newborns with BP measured on day 3 after birth were analyzed. Arm SBP/DBP and pulse rate in the reference group (n = 2628) were 70.5 ± 7.4/44.3 ± 6.7 mmHg and 117.3 ± 16.6 bpm, respectively. The 5-95th percentiles were 58-83 mmHg for SBP, 35-57 mmHg for DBP, and 91-145 bpm for pulse rate. Similar values were obtained from calf measurements. In multiple regression analysis, birth weight and spontaneous cephalic delivery were positively and light/deep sleep was inversely associated with higher arm SBP/DBP (P ≤ 0.04), whereas sex, Apgar score, gestational age, and mother's age did not significantly affect BP levels (P ≥ 0.06). Male sex, gestational age, spontaneous cephalic delivery, and light/deep sleep were inversely associated with higher pulse rate (P ≤ 0.02). The present study is the first to show the distributions of Asian newborns' BP levels and pulse rate. The assessment of newborns' BP levels and pulse rate should consider birth weight, gestational age after birth, and actual condition at BP measurement.

  4. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

    Directory of Open Access Journals (Sweden)

    Yongxin Chou

    2017-01-01

    Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

  5. Gas Hydrate Investigations Using Pressure Core Analysis: Current Practice

    Science.gov (United States)

    Schultheiss, P.; Holland, M.; Roberts, J.; Druce, M.

    2006-12-01

    Recently there have been a number of major gas hydrate expeditions, both academic and commercially oriented, that have benefited from advances in the practice of pressure coring and pressure core analysis, especially using the HYACINTH pressure coring systems. We report on the now mature process of pressure core acquisition, pressure core handling and pressure core analysis and the results from the analysis of pressure cores, which have revealed important in situ properties along with some remarkable views of gas hydrate morphologies. Pressure coring success rates have improved as the tools have been modified and adapted for use on different drilling platforms. To ensure that pressure cores remain within the hydrate stability zone, tool deployment, recovery and on-deck handling procedures now mitigate against unwanted temperature rises. Core analysis has been integrated into the core transfer protocol and automated nondestructive measurements, including P-wave velocity, gamma density, and X-ray imaging, are routinely made on cores. Pressure cores can be subjected to controlled depressurization experiments while nondestructive measurements are being made, or cores can be stored at in situ conditions for further analysis and subsampling.

  6. Evaluation of the effect of systolic blood pressure and pulse pressure on cognitive function: the Women's Health and Aging Study II.

    Directory of Open Access Journals (Sweden)

    Sevil Yasar

    Full Text Available Evidence suggests that elevated systolic blood pressure (SBP and pulse pressure (PP in midlife is associated with increased risk for cognitive impairment later in life. There is mixed evidence regarding the effects of late life elevated SBP or PP on cognitive function, and limited information on the role of female gender.Effects of SBPand PPon cognitive abilities at baseline and over a 9-year period were evaluated in 337 non-demented community-dwelling female participants over age 70 in the Women's Health and Aging Study II using logistic and Cox proportional hazards regression analyses. Participants aged 76-80 years with SBP≥160 mmHg or PP≥84 mmHg showed increased incidence of impairment on Trail Making Test-Part B (TMT, Part B, a measure of executive function, over time when compared to the control group that included participants with normal and pre-hypertensive SBP (<120 and 120-139 mmHg or participants with low PP (<68 mmHg (HR = 5.05 [95%CI = 1.42, 18.04], [HR = 5.12 [95%CI = 1.11; 23.62], respectively. Participants aged 70-75 years with PP≥71 mmHg had at least a two-fold higher incidence of impairment on HVLT-I, a measure of verbal learning, over time when compared to participants with low PP (<68 mmHg (HR = 2.44 [95%CI = 1.11, 5.39].Our data suggest that elevated SBP or PP in older non-demented women increases risk for late-life cognitive impairment and that PP could be used when assessing the risk for impairment in cognitive abilities. These results warrant further, larger studies to evaluate possible effects of elevated blood pressure in normal cognitive aging.

  7. Experimental study of plume induced by nanosecond repetitively pulsed spark microdischarges in air at atmospheric pressure

    Science.gov (United States)

    Orriere, Thomas; Benard, Nicolas; Moreau, Eric; Pai, David

    2016-09-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been widely studied due to their high chemical reactivity, low gas temperature, and high ionization efficiency. They are useful in many research areas: nanomaterials synthesis, combustion, and aerodynamic flow control. In all of these fields, particular attention has been devoted to chemical species transport and/or hydrodynamic and thermal effects for applications. The aim of this study is to generate an electro-thermal plume by combining an NRP spark microdischarge in a pin-to-pin configuration with a third DC-biased electrode placed a few centimeters away. First, electrical characterization and optical emission spectroscopy were performed to reveal important plasma processes. Second, particle image velocimetry was combined with schlieren photography to investigate the main characteristics of the generated flow. Heating processes are measured by using the N2(C ->B) (0,2) and (1,3) vibrational bands, and effects due to the confinement of the discharge are described. Moreover, the presence of atomic ions N+ and O+ is discussed. Finally, the electro-thermal plume structure is characterized by a flow velocity around 1.8 m.s-1, and the thermal kernel has a spheroidal shape.

  8. Pulsed high-pressure (PHP) drain-down of steam generating system

    International Nuclear Information System (INIS)

    Petrusek, R.A.

    1991-01-01

    This patent describes an improved method of draining down contained reactor-coolant water from the inverted vertical U-tubes of at least one vertical-type steam generator in which the upper inverted U-shaped ends of the tubes are closed and the lower ends thereof are open, the steam generator having a channel head at its lower end including a vertical dividing wall defining a primary water inlet side and a primary water outlet side of the generator, the steam generator having chemical volume control system means and residual heat removal system means, and the steam generator being part of a nuclear-powered steam generating system wherein the reactor-coolant water is normally circulated from and back into the reactor via a loop comprising the steam generator and inlet and outlet conduits connected to the lower end of the steam generator, and the reactor being in communication with pressurizer means and comprising the steps of introducing a gas which is inert to the system and which is under pressure above atmospheric pressure into at least one of the downwardly facing open ends of each of the U-tubes from below the tubesheet in which the open ends of the U-tubes are mounted adjacent the lower end of the steam generator while permitting the water to flow out from the open ends of the U-tubes, the improvement in combination therewith for substantially increasing the effectiveness and efficiency of such water removal from the tubes. It includes determining the parameters effecting a first average volumetric rate of removal for a predetermined period of time, infra, of the reactor-coolant water from the inverted vertical U-tubes, the specific unit for the first average volumetric rate expressing properties identical with the properties expressed in a second average volumetric rate maintained in a later mentioned step

  9. Job strain associated with increases in ambulatory blood and pulse pressure during and after work hours among female hotel room cleaners.

    Science.gov (United States)

    Feaster, Matt; Krause, Niklas

    2018-06-01

    Previously documented elevated hypertension rates among Las Vegas hotel room cleaners are hypothesized to be associated with job strain. Job strain was assessed by questionnaire. Ambulatory blood pressure (ABP) was recorded among 419 female cleaners from five hotels during 18 waking hours. Multiple linear regression models assessed associations of job strain with ABP and pulse pressure for 18-h, work hours, and after work hours. Higher job strain was associated with increased 18-h systolic ABP, after work hours systolic ABP, and ambulatory pulse pressure. Dependents at home but not social support at work attenuated effects. Among hypertensive workers, job strain effects were partially buffered by anti-hypertensive medication. High job strain is positively associated with blood pressure among female hotel workers suggesting potential for primary prevention at work. Work organizational changes, stress management, and active ABP surveillance and hypertension management should be considered for integrated intervention programs. © 2018 Wiley Periodicals, Inc.

  10. The local response of elastic tubes and shells to spherical pressure pulse loading

    International Nuclear Information System (INIS)

    Thompson, J.J.; Holy, Z.J.

    1977-01-01

    This paper develops a formulation and numerical solution technique for calculating the peak transient stresses developed in tubes or shells with external and internal acoustic media, as a result of shock loadings which may be represented as originating from external or internal point symmetric or dipole sources. The field of application is intended to be the local peak response of the cylindrical fuel cans, core barrels, pressure vessels, pipes and containment shells of Nuclear Reactor Technology, subjected to transient pressure shock loadings for a variety of operational or accident conditions, which cannot adequately be described as one dimensional plane shocks, for which elastic shell responses have been presented by other workers. The work reported here concerns the basic problem of an infinite static fluid filled hollow cylinder of arbitrary thickness, in an infinite static fluid medium, with a source at an arbitrary internal or external radial location. An acoustic model is used, with acoustic damping due to radiation as the only possible damping mechanism. The formulation and solution technique is based on the availability of the multi-dimensional Fast Fourier Transform algorithm. The basic result is the representation, in cylindrical co-ordinates, of the two dimensional (time and axial co-ordinate) Fourier Transform of the infinite medium frequency response function for outgoing waves from a point symmetrical source, as a series of azimuthal Fourier harmonics, from which the result for a dipole source of arbitrary orientation follows. Where possible numerical results will be presented

  11. Dual-Pulse Pulse Position Modulation (DPPM) for Deep-Space Optical Communications: Performance and Practicality Analysis

    Science.gov (United States)

    Li, Jing; Hylton, Alan; Budinger, James; Nappier, Jennifer; Downey, Joseph; Raible, Daniel

    2012-01-01

    Due to its simplicity and robustness against wavefront distortion, pulse position modulation (PPM) with photon counting detector has been seriously considered for long-haul optical wireless systems. This paper evaluates the dual-pulse case and compares it with the conventional single-pulse case. Analytical expressions for symbol error rate and bit error rate are first derived and numerically evaluated, for the strong, negative-exponential turbulent atmosphere; and bandwidth efficiency and throughput are subsequently assessed. It is shown that, under a set of practical constraints including pulse width and pulse repetition frequency (PRF), dual-pulse PPM enables a better channel utilization and hence a higher throughput than it single-pulse counterpart. This result is new and different from the previous idealistic studies that showed multi-pulse PPM provided no essential information-theoretic gains than single-pulse PPM.

  12. On the use of pulsed Dielectric Barrier Discharges to control the gas-phase composition of atmospheric pressure air plasmas

    Science.gov (United States)

    Barni, R.; Biganzoli, I.; Dell'Orto, E.; Riccardi, C.

    2014-11-01

    We presents results obtained from the numerical simulation of the gas-phase chemical kinetics in atmospheric pressure air non-equilibrium plasmas. In particular we have addressed the effect of pulsed operation mode of a plane dielectric barrier discharge. It was conjectured that the large difference in the time scales involved in the fast dissociation of oxygen molecules in plasma and their subsequent reactions to produce ozone and nitrogen oxides, makes the presence of a continuously repeated plasma production unnecessary and a waste of electrical power and thus efficiency. In order to test such suggestion we have performed a numerical study of the composition and the temporal evolution of the gas-phase of atmospheric pressure air non-equilibrium plasmas. Comparison with experimental findings in a dielectric barrier discharge with an electrode configuration symmetrical and almost ideally plane is briefly addressed too, using plasma diagnostics to extract the properties of the single micro-discharges and a sensor to measure the concentration of ozone produced by the plasma.

  13. On the use of pulsed Dielectric Barrier Discharges to control the gas-phase composition of atmospheric pressure air plasmas

    International Nuclear Information System (INIS)

    Barni, R; Biganzoli, I; Dell'Orto, E; Riccardi, C

    2014-01-01

    We presents results obtained from the numerical simulation of the gas-phase chemical kinetics in atmospheric pressure air non-equilibrium plasmas. In particular we have addressed the effect of pulsed operation mode of a plane dielectric barrier discharge. It was conjectured that the large difference in the time scales involved in the fast dissociation of oxygen molecules in plasma and their subsequent reactions to produce ozone and nitrogen oxides, makes the presence of a continuously repeated plasma production unnecessary and a waste of electrical power and thus efficiency. In order to test such suggestion we have performed a numerical study of the composition and the temporal evolution of the gas-phase of atmospheric pressure air non-equilibrium plasmas. Comparison with experimental findings in a dielectric barrier discharge with an electrode configuration symmetrical and almost ideally plane is briefly addressed too, using plasma diagnostics to extract the properties of the single micro-discharges and a sensor to measure the concentration of ozone produced by the plasma

  14. Comparison of yoga and walking-exercise on cardiac time intervals as a measure of cardiac function in elderly with increased pulse pressure.

    Science.gov (United States)

    Patil, Satish Gurunathrao; Patil, Shankargouda S; Aithala, Manjunatha R; Das, Kusal Kanti

    Arterial aging along with increased blood pressure(BP) has become the major cardiovascular(CV) risk in elderly. The aim of the study was to compare the effects of yoga program and walking-exercise on cardiac function in elderly with increased pulse pressure (PP). An open label, parallel-group randomized controlled study design was adopted. Elderly individuals aged ≥60 years with PP≥60mmHg were recruited for the study. Yoga (study) group (n=30) was assigned for yoga training and walking (exercise) group (n=30) for walking with loosening practices for one hour in the morning for 6days in a week for 3 months. The outcome measures were cardiac time intervals derived from pulse wave analysis and ECG: resting heart rate (RHR), diastolic time(DT), ventricular ejection time(LVET), upstroke time(UT), ejection duration index (ED%), pre-ejection period (PEP), rate pressure product (RPP) and percentage of mean arterial pressure (%MAP). The mean within-yoga group change in RHR(bpm) was 4.41 (p=0.031), PD(ms): -50.29 (p=0.042), DT(ms): -49.04 (p=0.017), ED%: 2.107 (p=0.001), ES(mmHg/ms): 14.62 (p=0.118), ET(ms): -0.66 (p=0.903), UT(ms): -2.54 (p=0.676), PEP(ms): -1.25 (p=0.11) and %MAP: 2.08 (p=0.04). The mean within-control group change in HR (bpm) was 0.35 (p=0.887), PD (ms): 11.15(p=0.717), DT (ms): 11.3 (p=0.706), ED%: -0.101 (p=0.936), ES (mmHg/ms): 0.75 (p=0.926), ET(ms): 2.2 (p=0.721), UT(ms):4.7(p=455), PEP (ms): 2.1(p=0.11), %MAP: 0.65 (p=0.451). A significant difference between-group was found in RHR (p=0.036), PD (p=0.02), ED% (p=0.049), LVET (p=0.048), DT (p=0.02) and RPP (p=0.001). Yoga practice for 3 months showed a significant improvement in diastolic function with a minimal change in systolic function. Yoga is more effective than walking in improving cardiac function in elderly with high PP. Copyright © 2017 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  15. Analysis of high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.

    2009-01-01

    In presently used safety valve sizing standards the gas discharge capacity is based on a nozzle flow derived from ideal gas theory. At high pressures or low temperatures real gas effects can no longer be neglected, so the discharge coefficient corrected for flow losses cannot be assumed constant

  16. Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

    Science.gov (United States)

    Thom, Karlheinz; Norwood, Joseph, Jr.

    1961-01-01

    The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

  17. [The influence of cryochamber on parameters of blood pressure and pulse].

    Science.gov (United States)

    Szczepanowska-Wołowiec, Beata; Dudek, Jolanta; Wołowiec, Paulina; Kotela, Ireneusz

    2010-01-01

    The influence of whole body cryotherapy on human body. The study was conducted on a group of 50 patients of the Rehabilitation Ward in Wojewodzki Szpital Zespolony in Kielce suffering from chronic pain as a sequel of degenerative-deformative changes and residing. Physiotherapy consisted of treatments in cryo-chamber and physical exercises. The average heart rate in the study group before the treatment amounted to 66.5 beats/min +/- 5.7 after the courses of treatments it constituted to 63.1 beats/min. +/- 3.6 at the significance level p whole body cryotherapy and 10 courses of those combined with physical exercises caused statistically significant reduction in the heart rate and pressure parameters. The downward trend was observed in all courses of treatments conducted in this study.

  18. Numerical Analysis on Transient of Steam-gas Pressurizer

    International Nuclear Information System (INIS)

    Kim, Jong-Won; Lee, Yeon-Gun; Park, Goon-Cherl

    2008-01-01

    In nuclear reactors, various pressurizers are adopted to satisfy their characteristics and uses. The additional active systems such as heater, pressurizer cooler, spray and insulator are essential for a steam or a gas pressurizer. With a steam-gas pressurizer, additional systems are not required due to the use of steam and non-condensable gas as pressure-buffering materials. The steam-gas pressurizer in integrated small reactors experiences very complicated thermal-hydraulic phenomena. To ensure the integrity of this pressurizer type, the analysis on the transient behavior of the steam-gas pressure is indispensable. For this purpose, the steam-gas pressurizer model is introduced to predict the accurate system pressure. The proposed model includes bulk flashing, rainout, inter-region heat and mass transfer and wall condensation with non-condensable gas. However, the ideal gas law is not applied because of significant interaction at high pressure between steam and non-condensable gas. The results obtained from this proposed model agree with those from pressurizer tests. (authors)

  19. Applicability of Pulse Pressure Variation during Unstable Hemodynamic Events in the Intensive Care Unit: A Five-Day Prospective Multicenter Study

    Directory of Open Access Journals (Sweden)

    Bertrand Delannoy

    2016-01-01

    Full Text Available Pulse pressure variation can predict fluid responsiveness in strict applicability conditions. The purpose of this study was to describe the clinical applicability of pulse pressure variation during episodes of patient hemodynamic instability in the intensive care unit. We conducted a five-day, seven-center prospective study that included patients presenting with an unstable hemodynamic event. The six predefined inclusion criteria for pulse pressure variation applicability were as follows: mechanical ventilation, tidal volume >7 mL/kg, sinus rhythm, no spontaneous breath, heart rate/respiratory rate ratio >3.6, absence of right ventricular dysfunction, or severe valvulopathy. Seventy-three patients presented at least one unstable hemodynamic event, with a total of 163 unstable hemodynamic events. The six predefined criteria for the applicability of pulse pressure variation were completely present in only 7% of these. This data indicates that PPV should only be used alongside a strong understanding of the relevant physiology and applicability criteria. Although these exclusion criteria appear to be profound, they likely represent an absolute contraindication of use for only a minority of critical care patients.

  20. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice: Part II: Impact on specific chemical and biochemical quality parameters

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, van der I.; Grauwet, T.; Timmermans, R.A.H.; Mastwijk, H.C.; Matser, A.M.; Hendrickx, M.E.; Loey, van A.

    2011-01-01

    The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical

  1. Relation of pulse pressure to long-distance gait speed in community-dwelling older adults: Findings from the LIFE-P study

    Science.gov (United States)

    Reduced long-distance gait speed, a measure of physical function, is associated with falls, late-life disability, hospitalization/institutionalization and cardiovascular morbidity and mortality. Aging is also accompanied by a widening of pulse pressure (PP) that contributes to ventricular-vascular ...

  2. The impact of arm position and pulse pressure on the validation of a wrist-cuff blood pressure measurement device in a high risk population

    Directory of Open Access Journals (Sweden)

    Ali Reza Khoshdel

    2010-03-01

    Full Text Available Ali Reza Khoshdel1,2, Shane Carney2, Alastair Gillies21Faculty of Medicine, Aja University of Medical Science, Tehran, Iran; 2John Hunter Hospital, Faculty of Health, The University of Newcastle, Newcastle, NS W, AustraliaAbstract: Despite the increasing popularity of blood pressure (BP wrist monitors for self-BP measurement at home, device validation and the effect of arm position remains an issue. This study focused on the validation of the Omron HEM-609 wrist BP device, including an evaluation of the impact of arm position and pulse pressure on BP measurement validation. Fifty patients at high risk for cardiovascular disease were selected (age 65 ± 10 years. Each patient had two measurements with a mercury sphygmomanometer and three measurements with the wrist BP device (wrist at the heart level while the horizontal arm supported [HORIZONTAL], hand supported on the opposite shoulder [SHOULDER], and elbow placed on a desk [DESK], in random order. The achieved systolic BP (SBP and diastolic BP (DBP wrist-cuff readings were compared to the mercury device and the frequencies of the readings within 5, 10, and 15 mmHg of the gold standard were computed and compared with the British Hypertension Society (BHS and Association for the Advancement of Medical Instrumentation (AAMI protocols. The results showed while SBP readings with HORIZONTAL and SHOULDER positions were significantly different from the mercury device (mean difference = 7.1 and 13.3 mmHg, respectively; P < 0.05, the DESK position created the closest reading to mercury (mean difference = 3.8, P > 0.1. Approximately 71% of SBP readings with the DESK position were within ±10 mmHg, whereas it was 62.5% and 34% for HORIZONTAL and SHOULDER positions, respectively. Wrist DBP attained category D with BHS criteria with all three arm positions. Bland–Altman plots illustrated that the wrist monitor systematically underestimated SBP and DBP values. However a reading adjustment of 5 and 10 mm

  3. Chirp analysis of high-order harmonics from atoms driven by intense femtosecond laser pulses

    International Nuclear Information System (INIS)

    Kim, Hyung Taek; Kim, I Jong; Hong, Kyung-Han; Lee, Dong Gun; Kim, Jung-Hoon; Nam, Chang Hee

    2004-01-01

    The spectral structure of harmonics was experimentally controlled by changing the chirp of femtosecond laser pulses, and the dependence of harmonic chirp on atomic species was analysed using harmonics from neon and helium. Experimental results and theoretical analysis based on the Wigner distribution function showed that the spectral structure varied sensitively to laser chirp and the harmonic chirp was determined by the competition between dynamically induced negative chirp and self-phase modulation induced positive chirp. The generation of sharp and bright harmonics was achieved with appropriately chirped laser pulses under given experimental conditions, especially negatively chirped pulses in the case of laser intensity above the saturation intensity for optical-field ionization

  4. Pulse pileup effects of plasma electron temperature measurements by soft x-ray energy analysis

    International Nuclear Information System (INIS)

    Dyer, G.R.; Neilson, G.H.; Kelley, G.G.

    1978-10-01

    The electron temperature of hot plasmas is conveniently derived from bremsstrahlung spectra obtained by pulse-height analysis using a lithium-compensated silicon detector. Time-resolved temperature measurements require high counting rates, with ultimate rate limited by pulse pileup. To evaluate this limit, spectral distortion due to pileup and consequent effects on temperature determination are investigated. Expressions for distorted spectra are derived as functions of Maxwellian temperature and pileup fraction for both square and triangular pulse shapes. A comparison of temperatures obtained from distorted spectra with actual values indicates that measurements with less than 10% error can be made in the absence of line radiation, even from spectra containing 40% pileup

  5. On the motion of dayside auroras caused by a solar wind pressure pulse

    Directory of Open Access Journals (Sweden)

    A. Kozlovsky

    2005-02-01

    Full Text Available Global ultraviolet auroral images from the IMAGE satellite were used to investigate the dynamics of the dayside auroral oval responding to a sudden impulse (SI in the solar wind pressure. At the same time, the TV all-sky camera and the EISCAT radar on Svalbard (in the pre-noon sector allowed for detailed investigation of the auroral forms and the ionospheric plasma flow. After the SI, new discrete auroral forms appeared in the poleward part of the auroral oval so that the middle of the dayside oval moved poleward from about 70° to about 73° of the AACGM latitude. This poleward shift first occurred in the 15 MLT sector, then similar shifts were observed in the MLT sectors located more westerly, and eventually the shift was seen in the 6 MLT sector. Thus, the auroral disturbance "propagated" westward (from 15 MLT to 6 MLT at an apparent speed of the order of 7km/s. This motion of the middle of the auroral oval was caused by the redistribution of the luminosity within the oval and was not associated with the corresponding motion of the poleward boundary of the oval. The SI was followed by an increase in the northward plasma convection velocity. Individual auroral forms showed poleward progressions with velocities close to the velocity of the northward plasma convection. The observations indicate firstly a pressure disturbance propagation through the magnetosphere at a velocity of the order of 200km/s which is essentially slower than the velocity of the fast Alfvén (magnetosonic wave, and secondly a potential (curl-free electric field generation behind the front of the propagating disturbance, causing the motion of the auroras. We suggest a physical explanation for the slow propagation of the disturbance through the magnetosphere and a model for the electric field generation. Predictions of the model are supported by the global convection maps produced by the SuperDARN HF radars. Finally, the interchange instability and the eigenmode toroidal

  6. Hydrophobic treatment on polymethylmethacrylate surface by nanosecond-pulse DBDs in CF{sub 4} at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cheng [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Zhou, Yang [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Shao, Tao, E-mail: st@mail.iee.ac.cn [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Xie, Qing [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Baoding 071003 (China); Xu, Jiayu [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Wenjin [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-08-30

    Highlights: • Increase in hydrophobicity on PMMA is achieved after the DBD treatment in CF{sub 4}, and the water contact angle can increase from 68° to 100° after treatment. • Nanosecond-pulse DBD is used for the surface treatment and the power density is about 114.8 mW/cm{sup 2}. • The effects of applied voltage, CF{sub 4} flow, and time on plasma treatment are investigated. • Plasma treatment causes morphological change, significantly increases the roughness of the surface, and introduces fluorine-containing groups into the polymethylmethacrylate surface. • Hydrophobic behavior of the treated PMMA surface is slightly affected by the aging effect. - Abstract: Nanosecond-pulse dielectric barrier discharge (DBD) can provide non-thermal plasmas with extremely high energy and high density, which can result in a series of complicated physical and chemical reactions in the surface treatment of polymers. Therefore, in this paper, hydrophobic treatment of polymethylmethacrylate (PMMA) surface is conducted by nanosecond-pulse DBD in carbon tetrafluoride (CF{sub 4}) at atmospheric pressure. Investigations on surface morphology and chemical composition before and after the DBD treatment in CF{sub 4} are conducted with the contact angle measurement, atomic force microscope, Fourier transform infrared spectroscopy, and X-ray photoelectron spectrometer. The effects of the applied voltage, CF{sub 4} flow rate, and treatment time on the hydrophobic modification are studied. Results show that the contact angles of the treated PMMA surface increases with the applied voltage, and it could be greatly affected by the CF{sub 4} flow rate and the treatment time. The water contact angle can increase from 68° to 100° after the treatment. Furthermore, both surface morphology and chemical composition of the PMMA samples are changed. Both the increase of the surface roughness and the occurrence of fluorine-containing functional groups on the PMMA surface treated by DBD in CF

  7. Analysis of a delayed epidemic model with pulse vaccination

    International Nuclear Information System (INIS)

    Samanta, G.P.

    2014-01-01

    In this paper, we have considered a dynamical model of infectious disease that spread by asymptomatic carriers and symptomatically infectious individuals with varying total population size, saturation incidence rate and discrete time delay to become infectious. It is assumed that there is a time lag (τ) to account for the fact that an individual infected with bacteria or virus is not infectious until after some time after exposure. The probability that an individual remains in the latency period (exposed class) at least t time units before becoming infectious is given by a step function with value 1 for 0⩽t⩽τ and value zero for t>τ. The probability that an individual in the latency period has survived is given by e -μτ , where μ denotes the natural mortality rate in all epidemiological classes. Pulse vaccination is an effective and important strategy for the elimination of infectious diseases and so we have analyzed this model with pulse vaccination. We have defined two positive numbers R 1 and R 2 . It is proved that there exists an infection-free periodic solution which is globally attractive if R 1 <1 and the disease is permanent if R 2 >1. The important mathematical findings for the dynamical behaviour of the infectious disease model are also numerically verified using MATLAB. Finally epidemiological implications of our analytical findings are addressed critically

  8. A Novel Mobile Phone Application for Pulse Pressure Variation Monitoring Based on Feature Extraction Technology: A Method Comparison Study in a Simulated Environment.

    Science.gov (United States)

    Desebbe, Olivier; Joosten, Alexandre; Suehiro, Koichi; Lahham, Sari; Essiet, Mfonobong; Rinehart, Joseph; Cannesson, Maxime

    2016-07-01

    Pulse pressure variation (PPV) can be used to assess fluid status in the operating room. This measurement, however, is time consuming when done manually and unreliable through visual assessment. Moreover, its continuous monitoring requires the use of expensive devices. Capstesia™ is a novel Android™/iOS™ application, which calculates PPV from a digital picture of the arterial pressure waveform obtained from any monitor. The application identifies the peaks and troughs of the arterial curve, determines maximum and minimum pulse pressures, and computes PPV. In this study, we compared the accuracy of PPV generated with the smartphone application Capstesia (PPVapp) against the reference method that is the manual determination of PPV (PPVman). The Capstesia application was loaded onto a Samsung Galaxy S4 phone. A physiologic simulator including PPV was used to display arterial waveforms on a computer screen. Data were obtained with different sweep speeds (6 and 12 mm/s) and randomly generated PPV values (from 2% to 24%), pulse pressure (30, 45, and 60 mm Hg), heart rates (60-80 bpm), and respiratory rates (10-15 breaths/min) on the simulator. Each metric was recorded 5 times at an arterial height scale X1 (PPV5appX1) and 5 times at an arterial height scale X3 (PPV5appX3). Reproducibility of PPVapp and PPVman was determined from the 5 pictures of the same hemodynamic profile. The effect of sweep speed, arterial waveform scale (X1 or X3), and number of images captured was assessed by a Bland-Altman analysis. The measurement error (ME) was calculated for each pair of data. A receiver operating characteristic curve analysis determined the ability of PPVapp to discriminate a PPVman > 13%. Four hundred eight pairs of PPVapp and PPVman were analyzed. The reproducibility of PPVapp and PPVman was 10% (interquartile range, 7%-14%) and 6% (interquartile range, 3%-10%), respectively, allowing a threshold ME of 12%. The overall mean bias for PPVappX1 was 1.1% within limits of

  9. Genome-wide association analysis identifies novel blood pressure loci and offers biological insights into cardiovascular risk

    NARCIS (Netherlands)

    Warren, Helen R.; Evangelou, Evangelos; Cabrera, Claudia P.; Gao, He; Ren, Meixia; Mifsud, Borbala; Ntalla, Ioanna; Surendran, Praveen; Liu, Chunyu; Cook, James P.; Kraja, Aldi T.; Drenos, Fotios; Loh, Marie; Verweij, Niek; Marten, Jonathan; Karaman, Ibrahim; Lepe, Marcelo P. Segura; O'Reilly, Paul F.; Knight, Joanne; Snieder, Harold; Kato, Norihiro; He, Jiang; Tai, E. Shyong; Said, M. Abdullah; Porteous, David; Alver, Maris; Poulter, Neil; Farrall, Martin; Gansevoort, Ron T.; Padmanabhan, Sandosh; Magi, Reedik; Stanton, Alice; Connell, John; Bakker, Stephan J. L.; Metspalu, Andres; Shields, Denis C.; Thom, Simon; Brown, Morris; Sever, Peter; Esko, Tonu; Hayward, Caroline; van der Harst, Pim; Saleheen, Danish; Chowdhury, Rajiv; Chambers, John C.; Chasman, Daniel I.; Chakravarti, Aravinda; Newton-Cheh, Christopher; Lindgren, Cecilia M.; Levy, Daniel; Kooner, Jaspal S.; Keavney, Bernard; Tomaszewski, Maciej; Samani, Nilesh J.; Howson, Joanna M. M.; Tobin, Martin D.; Munroe, Patricia B.; Ehret, Georg B.; Wain, Louise V.; Barnes, Michael R.; Tzoulaki, Joanna; Caulfield, Mark J.; Elliott, Paul; Vaez, Ahmad; Jansen, Rick; Joehanes, Roby; van der Most, Peter J.; Erzurumluoglu, A. Mesut; O'Reilly, Paul; Rose, Lynda M.; Verwoert, Germaine C.; Hottenga, Jouke-Jan; Strawbridge, Rona J.; Arking, Dan E.; Hwang, Shih-Jen; Guo, Xiuqing; Kutalik, Zoltan; Trompet, Stella; Shrine, Nick; Teumer, Alexander; Ried, Janina S.; Bis, Joshua C.; Smith, Albert V.; Amin, Najaf; Nolte, Ilja M.; Lyytikainen, Leo-Pekka; Mahajan, Anubha; Wareham, Nicholas J.; Hofer, Edith; Joshi, Peter K.; Kristiansson, Kati; Traglia, Michela; Havulinna, Aki S.; Goel, Anuj; Nalls, Mike A.; Sober, Siim; Vuckovic, Dragana; Luan, Jian'an; del Greco, Fabiola M.; Ayers, Kristin L.; Marrugat, Jaume; Ruggiero, Daniela; Lopez, Lorna M.; Niiranen, Teemu; Enroth, Stefan; Jackson, Anne U.; Nelson, Christopher P.; Huffman, Jennifer E.; Zhang, Weihua; Gandin, Ilaria; Harris, Sarah E.; Zemonik, Tatijana; Lu, Yingchang; Shah, Nabi; de Borst, Martin H.; Mangino, Massimo; Prins, Bram P.; Campbell, Archie; Li-Gao, Ruifang; Chauhan, Ganesh; Oldmeadow, Christopher; Abecasis, Goncalo; Abedi, Maryam; Barbieri, Caterina M.; Batini, Chiara; Blake, Tineka; Boehnke, Michael; Bottinger, Erwin P.; Braund, Peter S.; Brumat, Marco; Campbell, Harry; Cocca, Massimiliano; Collins, Francis; Cordell, Heather J.; Damman, Jeffrey J.; Davies, Gail; de Geus, Eco J.; de Mutsert, Renee; Deelen, Joris; Demirkale, Yusuf; Doney, Alex S. F.; Dorr, Marcus; Ferreira, Teresa; Franberg, Mattias; Giedraitis, Vilmantas; Gieger, Christian; Giulianini, Franco; Gow, Alan J.; Hamsten, Anders; Harris, Tamara B.; Hofman, Albert; Holliday, Elizabeth G.; Jarvelin, Marjo-Riitta; Johansson, Asa; Johnson, Andrew D.; Jousilahti, Pekka; Jula, Antti; Kahonen, Mika; Kathiresan, Sekar; Khaw, Kay-Tee; Kolcic, Ivana; Koskinen, Seppo; Langenberg, Claudia; Larson, Marty; Launer, Lenore J.; Lehne, Benjamin; Liewald, David C. M.; Lin, Li; Lind, Lars; Mach, Francois; Mamasoula, Chrysovalanto; Menni, Cristina; Milaneschi, Yuri; Morgan, Anna; Morris, Andrew D.; Morrison, Alanna C.; Munson, Peter J.; Nandakumar, Priyanka; Nguyen, Quang Tri; Nutile, Teresa; Oldehinkel, Albertine J.; Oostra, Ben A.; Org, Elin; Palotie, Aarno; Pare, Guillaume; Pattie, Alison; Penninx, Brenda W. J. H.; Pramstaller, Peter P.; Raitakari, Olli T.; Rice, Kenneth; Ridker, Paul M.; Riese, Harriette; Ripatti, Samuli; Robino, Antonietta; Rotter, Jerome I.; Rudan, Igor; Saba, Yasaman; Saint Pierre, Aude; Sala, Cinzia F.; Sarin, Antti-Pekka; Schmidt, Reinhold; Scott, Rodney; Seelen, Marc A.; Siscovick, David; Sorice, Rossella; Stott, David J.; Sundstrom, Johan; Swertz, Morris; Taylor, Kent D.; Tzoulaki, Ioanna; Tzourio, Christophe; Uitterlinden, Andre G.; Volker, Uwe; Vollenweider, Peter; Wild, Sarah; Willemsen, Gonneke; Wright, Alan F.; Yao, Jie; Theriault, Sebastien; Conen, David; John, Attia; Debette, Stephanie; Mook-Kanamori, Dennis O.; Zeggini, Eleftheria; Spector, Tim D.; Palmer, Colin N. A.; Vergnaud, Anne-Claire; Loos, Ruth J. F.; Polasek, Ozren; Starr, John M.; Girotto, Giorgia; Lindgren, Cecila M.; Vitart, Veronique; Tuomilehto, Jaakko; Gyllensten, Ulf; Knekt, Paul; Deary, Ian J.; Ciullo, Marina; Elosua, Roberto; Keavney, Bernard D.; Hicks, Andrew A.; Scott, Robert A.; Gasparini, Paolo; Laan, Maris; Liu, Yongmei; Watkins, Hugh; Hartman, Catharina A.; Salomaa, Veikko; Toniolo, Daniela; Perola, Markus; Wilson, James F.; Schmidt, Helena; Zhao, Jing Hua; Lehtimaki, Terho; van Duijn, Cornelia M.; Gudnason, Vilmundur; Psaty, Bruce M.; Peters, Annette; Rettig, Rainer; James, Alan; Jukema, J. Wouter; Strachan, David P.; Palmas, Walter; Ingelsson, Erik; Boomsma, Dorret I.; Franco, Oscar H.; Bochud, Murielle; Morris, Andrew P.

    2017-01-01

    Elevated blood pressure is the leading heritable risk factor for cardiovascular disease worldwide. We report genetic association of blood pressure (systolic, diastolic, pulse pressure) among UK Biobank participants of European ancestry with independent replication in other cohorts, and robust

  10. Comparative performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs

    Directory of Open Access Journals (Sweden)

    Sudip Bhattrai

    2013-09-01

    Full Text Available Combined-cycle pulse detonation engines are promising contenders for hypersonic propulsion systems. In the present study, design and propulsive performance analysis of combined-cycle pulse detonation turbofan engines (PDTEs is presented. Analysis is done with respect to Mach number at two consecutive modes of operation: (1 Combined-cycle PDTE using a pulse detonation afterburner mode (PDA-mode and (2 combined-cycle PDTE in pulse detonation ramjet engine mode (PDRE-mode. The performance of combined-cycle PDTEs is compared with baseline afterburning turbofan and ramjet engines. The comparison of afterburning modes is done for Mach numbers from 0 to 3 at 15.24 km altitude conditions, while that of pulse detonation ramjet engine (PDRE is done for Mach 1.5 to Mach 6 at 18.3 km altitude conditions. The analysis shows that the propulsive performance of a turbine engine can be greatly improved by replacing the conventional afterburner with a pulse detonation afterburner (PDA. The PDRE also outperforms its ramjet counterpart at all flight conditions considered herein. The gains obtained are outstanding for both the combined-cycle PDTE modes compared to baseline turbofan and ramjet engines.

  11. Heritability and whole genome linkage of pulse pressure in Chinese twin pairs

    DEFF Research Database (Denmark)

    Jiang, Wengjie; Zhang, Dongfeng; Pang, Zengchang

    2012-01-01

    with a heritability estimate of 0.45. Genome-wide non-parametric linkage analysis identified three significant linkage peaks on chromosome 11 (lod score 4.06 at 30.5 cM), chromosome 12 (lod score 3.97 at 100.7 cM), and chromosome 18 (lod score 4.01 at 70.7 cM) with the last two peaks closely overlapping with linkage...

  12. Reproducibility of Radial Pulse Wave Analysis in Healthy Subjects

    Czech Academy of Sciences Publication Activity Database

    Filipovský, J.; Svoboda, V.; Pecen, Ladislav

    2000-01-01

    Roč. 18, č. 8 (2000), s. 1033-1040 ISSN 0263-6352 Institutional research plan: AV0Z1030915 Keywords : blood pressure * heart - rate * predictor * risk Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 3.640, year: 2000

  13. Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: A systematic review and meta-analysis.

    Science.gov (United States)

    Taggar, Jaspal S; Coleman, Tim; Lewis, Sarah; Heneghan, Carl; Jones, Matthew

    2016-08-01

    Pulse palpation has been recommended as the first step of screening to detect atrial fibrillation. We aimed to determine and compare the accuracy of different methods for detecting pulse irregularities caused by atrial fibrillation. We systematically searched MEDLINE, EMBASE, CINAHL and LILACS until 16 March 2015. Two reviewers identified eligible studies, extracted data and appraised quality using the QUADAS-2 instrument. Meta-analysis, using the bivariate hierarchical random effects method, determined average operating points for sensitivities, specificities, positive and negative likelihood ratios (PLR, NLR); we constructed summary receiver operating characteristic plots. Twenty-one studies investigated 39 interventions (n = 15,129 pulse assessments) for detecting atrial fibrillation. Compared to 12-lead electrocardiography (ECG) diagnosed atrial fibrillation, blood pressure monitors (BPMs; seven interventions) and non-12-lead ECGs (20 interventions) had the greatest accuracy for detecting pulse irregularities attributable to atrial fibrillation (BPM: sensitivity 0.98 (95% confidence interval (CI) 0.92-1.00), specificity 0.92 (95% CI 0.88-0.95), PLR 12.1 (95% CI 8.2-17.8) and NLR 0.02 (95% CI 0.00-0.09); non-12-lead ECG: sensitivity 0.91 (95% CI 0.86-0.94), specificity 0.95 (95% CI 0.92-0.97), PLR 20.1 (95% CI 12-33.7), NLR 0.09 (95% CI 0.06-0.14)). There were similar findings for smartphone applications (six interventions) although these studies were small in size. The sensitivity and specificity of pulse palpation (six interventions) were 0.92 (95% CI 0.85-0.96) and 0.82 (95% CI 0.76-0.88), respectively (PLR 5.2 (95% CI 3.8-7.2), NLR 0.1 (95% CI 0.05-0.18)). BPMs and non-12-lead ECG were most accurate for detecting pulse irregularities caused by atrial fibrillation; other technologies may therefore be pragmatic alternatives to pulse palpation for the first step of atrial fibrillation screening. © The European Society of Cardiology 2015.

  14. Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

    Science.gov (United States)

    Chundong, HU; Yongjian, XU; Yuanlai, XIE; Yahong, XIE; Lizhen, LIANG; Caichao, JIANG; Sheng, LIU; Jianglong, WEI; Peng, SHENG; Zhimin, LIU; Ling, TAO; the NBI Team

    2018-04-01

    Two sets of neutral beam injectors (NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with in-depth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that (1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline, (2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and (3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.

  15. Thermal Analysis of Cryocooler-Cooled Bi2223 Pulsed Coil

    International Nuclear Information System (INIS)

    Miyazaki, H; Chigusa, S; Tanaka, I; Iwakuma, M; Funaki, K; Hayashi, H; Tomioka, A

    2006-01-01

    We fabricated a cryocooler-cooled Bi2223 superconducting pulsed coil and experimentally studied thermal runaway in dc or ac operation. We carried out numerical simulation of thermal properties of the coil in order to explain thermal runaway of the coil. Firstly, we analyzed the total heat generation of flux-flow loss and ac loss inside the winding from the experimental results of the external field losses and the E-J characteristics for the Bi2223 strands. Secondly, we numerically simulated the thermal properties by using 2- dimensional heat conduction equation with axial symmetry. The numerical simulation shows the relation between the initiation of thermal runaway and the temperature distribution with highly concentrated heat source in the winding. We have a semi-quantitative agreement between the numerical results and the experimental ones for the condition of the thermal runaway

  16. A non-local model analysis of heat pulse propagation

    International Nuclear Information System (INIS)

    Iwasaki, T.; Itoh, S.I.; Yagi, M.; Stroth, U.

    1998-01-01

    The anomalous transport in high temperature plasma has been studied for a long time, from the beginning of the fusion research. Since the electron channel in stellarators and tokamaks is clearly anomalous, it is of fundamental importance to investigate the electron heat diffusivity coefficient, χ e and to understand the physical mechanism. Recently, the experimental data for the transient transport of the heat pulse propagation in fusion plasma has been accumulated. An observation was reported on W7-AS which the heat flux changes faster than the change of the temperature profile, responding to the switching on off of the central heating power. The observation on the transient response has simulated the transport modeling, e.g., the critical marginality which implies the existence of a finite threshold in ∇T for the excitation of the turbulence, or the model in which the thermal conductivity is assumed to depend on the heating power. Extensive study is made by use of these models, and the critical marginally model seems to be insufficient to explain various transient transport. The rapid change of the plasma state and its hysteresis nature were successfully modeled by a heating-power-dependent model. The foundation of this model, however, is left for future work. The development of the transport modeling remains to be an urgent problem. In this paper, we investigate the role of the non-locality of the plasma transport in the study of the heat pulse propagation. For this purpose, a model equation is proposed, in which the non-local effect is taken into account in the heat flux. The properties of this model are investigated by performing a transport simulation. The organization of this paper is as follows: In Sec. II, the model equation is proposed and the properties of the model are explained. Using the model equation, the switching on off experiment is simulated in Sec. III. Summary and discussion are given in Sec. IV. (author)

  17. Dry Electrodes for ECG and Pulse Transit Time for Blood Pressure: A Wearable Sensor and Smartphone Communication Approach

    Science.gov (United States)

    Shyamkumar, Prashanth

    -invasive, cuff-less Blood pressure estimation based on Pulse Transit Time with multiple synchronized sensor nodes, is implemented with e-nanoflex and the results are discussed.

  18. The choice of rational parameters of beet pulp drying process in a pulsed low-pressure vibro-boiling layer

    Directory of Open Access Journals (Sweden)

    A. V. Drannikov

    2017-01-01

    Full Text Available Beet pulp is the main sugar industry by-product obtained with traditional production technology. It has high nutritional qualities, but in its raw form it turns sour quickly so it must be preserved. One of the most common methods is drying. Drying of the beet pulp with superheated vapor of reduced pressure in the pulsating vibro-boiling layer allows to improve the quality of the finished product by lowering of the drying agent temperature, thereby retaining a significant amount of nutrients in the initial product. To study the kinetic and hydrodynamic dependencies of the drying process, an experimental apparatus was developed that makes it possible to obtain the most accurate and reproducible results. In the course of the work, a lot of experiments were carried out. Drying curves, drying rate curves and heating curves were made based on these experiments results. According to the nature of the changes the corresponding conclusions were drawn. To study the interaction of various factors affecting the beet pulp drying process, the mathematical methods of experiment planning are applied. A mathematical description of this process can be obtained empirically. At the same time, its mathematical model has the form of a regression equation, determined by statistical methods on the basis of experiments. As a result of statistical processing of experimental data, regression equations were obtained that adequately describe the beet pulp drying process in a pulsed low-pressure vibro-boiling layer in the experimental apparatus. With reference to this drying apparatus, such technological modes of its operation were determined that ensure a minimum specific energy consumption of the drying process per kilogram of evaporated moisture and the maximum drying chamber moisture stress.

  19. Artificial neural network based pulse-shape analysis for cryogenic detectors operated in CRESST-II

    Energy Technology Data Exchange (ETDEWEB)

    Zoeller, Andreas [Physik-Department and Excellence Cluster Universe, Technische Universitaet Muenchen, D-85747 Garching (Germany); Collaboration: CRESST-Collaboration

    2016-07-01

    In this talk we report on results of a pulse-shape analysis of cryogenic detectors based on artificial neural networks. To train the neural network a large amount of pulses with known properties are necessary. Therefore, a data-driven simulation used to generate these sets will be explained. The presented analysis shows an excellent discrimination performance even down to the energy threshold. The method is applied to several detectors, among them is the module with the lowest threshold (307eV) operated in CRESST-II phase 2. The performed blind analysis of this module confirms the substantially enhanced sensitivity for light dark matter published in 2015.

  20. Detection of low caloric power of coal by pulse fast-thermal neutron analysis

    International Nuclear Information System (INIS)

    Gu De-shan; Sang Hai-feng; Qiao Shuang; Liu Yu-ren, Liu Lin-mao; Jing Shi-wei; Chinese Academy of Sciences, Changchun

    2004-01-01

    Analysis method and principle of pulse fast-thermal neutron analysis (PFTNA) are introduced. A system for the measurement of low caloric power of coal by PFTNA is also presented. The 14 MeV pulse neutron generator and BGO detector and 4096 MCA were applied in this system. A multiple linear regression method applied to the data solved the interferential problem of multiple elements. The error of low caloric power between chemical analysis and experiment was less than 0.4 MJ/kg. (author)

  1. High-pressure single-crystal neutron diffraction (to 20 kbar) using a pulsed source: Preliminary investigation of Tl3PSe4

    International Nuclear Information System (INIS)

    Alkire, R.W.; Larson, A.C.; Vergamini, P.J.; Schirber, J.E.; Morosin, B.

    1985-01-01

    A new technique is described for performing high-pressure single-crystal neutron diffraction [up to 20 kbar (2GPa) at room temperature], using a BeCu pressure cell, an area detector and the Los Alamos National Laboratory pulsed neutron source. Success of this method depends on the increase in information available with a multi-wavelength pulse neutron source, a novel orientation of a cylindrically symmetric pressure cell with its axis coincident with the neutron beam and a specific crystal orientation within the pressure cell. Bragg scattering from the pressure cell is avoided and background for a given 2theta is constant. For a crystal of orthorhombic or higher symmetry oriented with the incident beam passing midway between the major lattice vectors, it will be possible to refine a complete three-dimensional structure with data collected from only one pressure loading. Preliminary investigations of Tl 3 PSe 4 lattice parameters (space group Pcmn) at 15(1)kbar yielded linear compressibilities (. 1000 in kbar -1 ) of Ksub(a) = 1.05(8), Ksub(b) = 1.50(10), Ksub(c) = 1.20(8). The anisotropic compressibility is explained by examination of the ambient-pressure room-temperature structure. (orig.)

  2. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

    Energy Technology Data Exchange (ETDEWEB)

    Engel, Robin, E-mail: robin.engel@uni-oldenburg.de [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany); Düsterer, Stefan; Brenner, Günter [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Teubner, Ulrich [Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg (Germany); Institut für Physik, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg (Germany); Institut für Laser und Optik, Hochschule Emden/Leer, University of Applied Sciences, Constantiaplatz 4, D-26723 Emden (Germany)

    2016-01-01

    Considering the second-order spectral correlation function of SASE-FEL radiation allows a real-time observation of the photon pulse duration during spectra acquisition. For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded.

  3. Pulsed-laser-deposited, single-crystalline Cu2O films with low resistivity achieved through manipulating the oxygen pressure

    Science.gov (United States)

    Liu, Xiaohui; Xu, Meng; Zhang, Xijian; Wang, Weiguang; Feng, Xianjin; Song, Aimin

    2018-03-01

    Low-resistivity, single-crystalline Cu2O films were realized on MgO (110) substrates through manipulating the oxygen pressure (PO2) of pulsed-laser deposition. X-ray diffraction and high resolution transmission electron microscopy measurements revealed that the films deposited at PO2 of 0.06 and 0.09 Pa were single phase Cu2O and the 0.09-Pa-deposited film exhibited the best crystallinity with an epitaxial relationship of Cu2O (110)∥MgO (110) with Cu2O (001)∥MgO (001). The pure phase Cu2O films exhibited higher transmittances and larger band gaps with an optical band gap of 2.56 eV obtained for the 0.09 Pa-deposited film. Hall-effect measurements demonstrated that the Cu2O film deposited at 0.09 Pa had the lowest resistivity of 6.67 Ω cm and highest Hall mobility of 23.75 cm2 v-1 s-1.

  4. Reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma

    Science.gov (United States)

    Zhao, Yuefeng; Wang, Chao; Li, Li; Wang, Lijuan; Pan, Jie

    2018-03-01

    In this work, a two-dimensional fluid model is built up to numerically investigate the reaction pathways of producing and losing particles in atmospheric pressure methane nanosecond pulsed needle-plane discharge plasma. The calculation results indicate that the electron collisions with CH4 are the key pathways to produce the neutral particles CH2 and CH as well as the charged particles e and CH3+. CH3, H2, H, C2H2, and C2H4 primarily result from the reactions between the neutral particles and CH4. The charge transfer reactions are the significant pathways to produce CH4+, C2H2+, and C2H4+. As to the neutral species CH and H and the charged species CH3+, the reactions between themselves and CH4 contribute to substantial losses of these particles. The ways responsible for losing CH3, H2, C2H2, and C2H4 are CH3 + H → CH4, H2 + CH → CH2 + H, CH4+ + C2H2 → C2H2+ + CH4, and CH4+ + C2H4 → C2H4+ + CH4, respectively. Both electrons and C2H4+ are consumed by the dissociative electron-ion recombination reactions. The essential reaction pathways of losing CH4+ and C2H2+ are the charge transfer reactions.

  5. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production.

    Science.gov (United States)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G; Banati, Diana; Pollák-Tóth, Annamária; Lakner, Zoltán; Olsen, Nina Veflen; Zontar, Tanja Pajk; Peterman, Marjana

    2009-02-01

    The success of new food processing technologies is highly dependent on consumers' acceptance. The purpose of this paper is to study consumers' perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline. Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show that consumers perceived the main advantages of HPP and PEF products to be the products' naturalness, improved taste and their high nutritional value, whereas the main disadvantage was the lack of information about the PEF and HPP products. The results of the participants' evaluation of the PEF and HPP processes showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European participants were a bit more sceptical towards PEF and HPP products than the East European participants.

  6. Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria

    Directory of Open Access Journals (Sweden)

    Briestenský Miloš

    2015-10-01

    Full Text Available The EU-TecNet monitoring network uses customized three-dimensional extensometers to record transient deformations across individual faults. This paper presents the first results from two newly established monitoring points in the Balkan Mountains in Bulgaria. The data from Saeva Dupka, recorded across an EEN-WWS striking fault, show sinistral strike-slip along the fault and subsidence of the southern block. Much of the subsidence occurred around the time of the distal MW = 5.6 Pernik Earthquake. An important transient deformation event, which began in autumn 2012, was reflected by significant compression and following extension, across the monitored fault. The data from Bacho Kiro, recorded across a NE–SW striking fault, show sinistral strike-slip along the fault and subsidence of the north-western block. The same important deformation event was reflected by changes in the strike-slip, dip-slip, and horizontal opening/closing trends. These results have been compared to data from other monitoring points in the Western Carpathians, External Dinarides, and Tian Shan. Many of the sites show evidence of simultaneous displacement anomalies and this observation is interpreted as a reflection of the plate-wide propagation of a tectonic pressure pulse towards the end of 2012.

  7. Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    International Nuclear Information System (INIS)

    Walsh, J L; Liu, D X; Iza, F; Kong, M G; Rong, M Z

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O 2 by helium metastables is significantly more efficient than electron dissociative excitation of O 2 , electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O 2 plasmas for excited atomic oxygen based chemistry. (fast track communication)

  8. FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    Science.gov (United States)

    Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

  9. Extension of thermophysical and thermodynamic property measurements by laser pulse heating up to 10,000 K. I. Under pressure

    Science.gov (United States)

    Ohse, R. W.

    1990-07-01

    The necessity for increased high-temperature data reliability and extension of thermophysical property measurements up to 5000 K and above are discussed. A new transient-type laser-autoclave technique (LAT) has been developed to extend density and heat capacity measurements of high-temperature multicomponent systems far beyond their melting and boiling points. Pulsed multibeam laser heating is performed in an autoclave under high inert gas pressure to eliminate evaporation. The spherical samples are positioned by containment-free acoustic levitation regardless of their conductive or magnetic properties. Temperature, spectral and total emittances are determined by a new microsecond six-wavelength pyrometer coupled to a fast digital data acquisition system. The density is determined by high resolution microfocus X-ray shadow technique. The heat capacity is obtained from the cooling rate. Further applications are a combination of the laser-autoclave with splat cooling techniques for metastable structure synthesis and amorphous metals research and an extension of the LAT for the study of critical phenomena and the measurement of critical-point temperatures.

  10. OH density measured by PLIF in a nanosecond atmospheric pressure diffuse discharge in humid air under steep high voltage pulses

    Science.gov (United States)

    Ouaras, K.; Magne, L.; Pasquiers, S.; Tardiveau, P.; Jeanney, P.; Bournonville, B.

    2018-04-01

    The spatiotemporal distributions of the OH radical density are measured using planar laser induced fluorescence in the afterglow of a nanosecond diffuse discharge at atmospheric pressure in humid air. The diffuse discharge is generated between a pin and a grounded plate electrodes within a gap of 18 mm. The high voltage pulse applied to the pin ranges from 65 to 85 kV with a rise time of 2 ns. The specific electrical energy transferred to the gas ranges from 5 to 40 J l‑1. The influence of H2O concentration is studied from 0.5% to 1.5%. An absolute calibration of OH density is performed using a six-level transient rate equation model to simulate the dynamics of OH excitation by the laser, taking into account collisional processes during the optical pumping and the fluorescence. Rayleigh scattering measurements are used to achieve the geometrical part of the calibration. A local maximum of OH density is found in the pin area whatever the operating conditions. For 85 kV and 1% of H2O, this peak reaches a value of 2.0 × 1016 cm‑3 corresponding to 8% of H2O dissociation. The temporal decay of the spatially averaged OH density is found to be similar as in the afterglow of a homogeneous photo-triggered discharge for which a self-consistent modeling is done. These tools are then used to bring discussion elements on OH kinetics.

  11. Effects of working gas pressure on zirconium dioxide thin film prepared by pulsed plasma deposition: roughness, wettability, friction and wear characteristics.

    Science.gov (United States)

    Berni, M; Marchiori, G; Gambardella, A; Boi, M; Bianchi, M; Russo, A; Visani, A; Marcacci, M; Pavan, P G; Lopomo, N F

    2017-08-01

    In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100m a reduction rate of about 7% in dry, 12% in NaCl and 5% in

  12. Component Analysis of Long-Lag, Wide-Pulse Gamma-Ray Burst ...

    Indian Academy of Sciences (India)

    Principal Component Analysis of Long-Lag, Wide-Pulse Gamma-Ray. Burst Data. Zhao-Yang Peng. ∗. & Wen-Shuai Liu. Department of Physics, Yunnan Normal University, Kunming 650500, China. ∗ e-mail: pzy@ynao.ac.cn. Abstract. We have carried out a Principal Component Analysis (PCA) of the temporal and spectral ...

  13. Monte Carlo simulations to advance characterisation of landmines by pulsed fast/thermal neutron analysis

    NARCIS (Netherlands)

    Maucec, M.; Rigollet, C.

    The performance of a detection system based on the pulsed fast/thermal neutron analysis technique was assessed using Monte Carlo simulations. The aim was to develop and implement simulation methods, to support and advance the data analysis techniques of the characteristic gamma-ray spectra,

  14. TRACE ANALYSIS BY LASER-EXCITED ATOMIC FLUORESCENCE WITH ATOMIZATION IN A PULSED PLASMA

    OpenAIRE

    Lunyov , O.; Oshemkov , S.; Petrov , A.

    1991-01-01

    The possibilities of plasma atomization for laser fluorescence trace analysis are discussed. Pulsed hot hollow cathode discharge was used for analysis of solutions and powdered samples. The high voltage spark and laser-induced breakdown (laser spark) were used as atomizers of metal-containing atmospheric aerosols. Detection limits were improved by means of temporal background selection.

  15. Multi-pressure boiler thermodynamics analysis code

    International Nuclear Information System (INIS)

    Lorenzoni, G.

    1992-01-01

    A new method and the relative FORTRAN program for the thermodynamics design analysis of a multipressure boiler are reported. This method permits the thermodynamics design optimization with regard to total exergy production and a preliminary costs

  16. Pressure analysis in ventilation ducts at bituminization facility

    International Nuclear Information System (INIS)

    Kikuchi, Naoki; Iimura, Masato; Takahashi, Yuki; Omori, Eiichi; Yamanouchi, Takamichi

    1997-09-01

    Pressure analysis in cell ventilation ducts at bituminization facility where the fire and explosion accident occured was carried out. This report also describes the results of bench mark calculations for computer code EVENT84 which was used for the accident analysis. The bench mark calculations were performed by comparing the analytical results by EVENT84 code with the experimental data of safety demonstration tests of ventilation system which were carried out by JAERI. We confirmed the applicability of EVENT84 code with the conservative results. The pressure analysis in cell ventilation ducts at bituminization facility were performed by comparing the analytical results of duct pressure by EVENT84 code with the yield stress of destroyed ducts by explosion, in order to estimate the scale of explosion. As a result, we could not explain the damage of ducts quantitatively, but we found the local pressure peaks analytically in downstream ducts where the serious damages were observed. (author)

  17. Non-local model analysis of heat pulse propagation

    International Nuclear Information System (INIS)

    Iwasaki, Takuya; Itoh, Sanae-I.; Yagi, Masatoshi

    1998-01-01

    A new theoretical model equation which includes the non-local effect in the heat flux is proposed to study the transient transport phenomena. A non-local heat flux, which is expressed in terms of the integral equation, is superimposed on the conventional form of the heat flux. This model is applied to describe the experimental results from the power switching [Stroth U, et al 1996 Plasma Phys. Control. Fusion 38 1087] and the power modulation experiments [Giannone L, et al 1992 Nucl. Fusion 32 1985] in the W7-AS stellarator. A small fraction of non-local component in the heat flux is found to be very effective in modifying the response against an external modulation. The transient feature of the transport property, which are observed in the response of heat pulse propagation, are qualitatively reproduced by the transport simulations based on this model. A possibility is discussed to determine the correlation length of the non-local effect experimentally by use of the results of transport simulations. (author)

  18. Water Flow Testing and Unsteady Pressure Analysis of a Two-Bladed Liquid Oxidizer Pump Inducer

    Science.gov (United States)

    Schwarz, Jordan B.; Mulder, Andrew; Zoladz, Thomas

    2011-01-01

    The unsteady fluid dynamic performance of a cavitating two-bladed oxidizer turbopump inducer was characterized through sub-scale water flow testing. While testing a novel inlet duct design that included a cavitation suppression groove, unusual high-frequency pressure oscillations were observed. With potential implications for inducer blade loads, these high-frequency components were analyzed extensively in order to understand their origins and impacts to blade loading. Water flow testing provides a technique to determine pump performance without the costs and hazards associated with handling cryogenic propellants. Water has a similar density and Reynolds number to liquid oxygen. In a 70%-scale water flow test, the inducer-only pump performance was evaluated. Over a range of flow rates, the pump inlet pressure was gradually reduced, causing the flow to cavitate near the pump inducer. A nominal, smooth inducer inlet was tested, followed by an inlet duct with a circumferential groove designed to suppress cavitation. A subsequent 52%-scale water flow test in another facility evaluated the combined inducer-impeller pump performance. With the nominal inlet design, the inducer showed traditional cavitation and surge characteristics. Significant bearing loads were created by large side loads on the inducer during synchronous cavitation. The grooved inlet successfully mitigated these loads by greatly reducing synchronous cavitation, however high-frequency pressure oscillations were observed over a range of frequencies. Analytical signal processing techniques showed these oscillations to be created by a rotating, multi-celled train of pressure pulses, and subsequent CFD analysis suggested that such pulses could be created by the interaction of rotating inducer blades with fluid trapped in a cavitation suppression groove. Despite their relatively low amplitude, these high-frequency pressure oscillations posed a design concern due to their sensitivity to flow conditions and

  19. Quality analysis in pressurized water reactor fuel

    International Nuclear Information System (INIS)

    Darolles, J.F.

    1975-01-01

    An integrated system which has been set up to administrate and analyze the quality is described. This system is in actual operation. The basic principles for quality analysis system are traceability, i.e., identification, location and history of fuel components and quality evaluation during manufacturing. The quality analysis system operates in the following areas: data recording and transmission, data processing, quality file generation. The interest of such a system may be noted particularly in manufacturing, for the constitution of quality files, the design of products and the processing of data from irradiated fuel assemblies [fr

  20. Pulsed Direct Current Electrospray: Enabling Systematic Analysis of Small Volume Sample by Boosting Sample Economy.

    Science.gov (United States)

    Wei, Zhenwei; Xiong, Xingchuang; Guo, Chengan; Si, Xingyu; Zhao, Yaoyao; He, Muyi; Yang, Chengdui; Xu, Wei; Tang, Fei; Fang, Xiang; Zhang, Sichun; Zhang, Xinrong

    2015-11-17

    We had developed pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS) for systematically profiling and determining components in small volume sample. Pulsed-dc-ESI utilized constant high voltage to induce the generation of single polarity pulsed electrospray remotely. This method had significantly boosted the sample economy, so as to obtain several minutes MS signal duration from merely picoliter volume sample. The elongated MS signal duration enable us to collect abundant MS(2) information on interested components in a small volume sample for systematical analysis. This method had been successfully applied for single cell metabolomics analysis. We had obtained 2-D profile of metabolites (including exact mass and MS(2) data) from single plant and mammalian cell, concerning 1034 components and 656 components for Allium cepa and HeLa cells, respectively. Further identification had found 162 compounds and 28 different modification groups of 141 saccharides in a single Allium cepa cell, indicating pulsed-dc-ESI a powerful tool for small volume sample systematical analysis.

  1. A Meta-Analysis about the Screening Role of Pulse Oximetry for Congenital Heart Disease

    Directory of Open Access Journals (Sweden)

    Caiju Du

    2017-01-01

    Full Text Available Objective. The opinions about the application of pulse oximetry in diagnosis of congenital heart disease (CHD were debatable. We performed this meta-analysis to confirm the diagnostic role of pulse oximetry screening for CHD. Methods. Relevant articles were searched in the databases of Pubmed, Embase, Google Scholar, and Chinese National Knowledge Infrastructure (CNKI up to April 2017. Data was processed in the MetaDiSc 1.4 software. Pooled sensitivity and specificity with 95% confidence interval (95% CI were calculated to explain the diagnostic role of pulse oximetry screening for CHD. I2⩾50% or p<0.05 indicated significant heterogeneity. Area under curve (AUC of summary receiver operating characteristics (SROC was calculated to assess its diagnostic accuracy. The robustness of overall results was evaluated by sensitivity analysis. Publication bias was evaluated by Deek’s funnel plot. Results. 22 eligible articles were selected. Pooled sensitivity and specificity were 0.69 (0.67–0.72 and 0.99 (0.99-0.99, respectively. The corresponding AUC was 0.9407, suggesting high diagnostic accuracy of pulse oximetry screening for CHD. Sensitivity analysis demonstrated that the pooled results were robust. Deek’s funnel plot seemed to be symmetrical. Conclusions. Pulse oximetry screening could be used to diagnose CHD. It shows high diagnosis specificity and accuracy.

  2. The Real-time Frequency Spectrum Analysis of Neutron Pulse Signal Series

    International Nuclear Information System (INIS)

    Tang Yuelin; Ren Yong; Wei Biao; Feng Peng; Mi Deling; Pan Yingjun; Li Jiansheng; Ye Cenming

    2009-01-01

    The frequency spectrum analysis of neutron pulse signal is a very important method in nuclear stochastic signal processing Focused on the special '0' and '1' of neutron pulse signal series, this paper proposes new rotation-table and realizes a real-time frequency spectrum algorithm under 1G Hz sample rate based on PC with add, address and SSE. The numerical experimental results show that under the count rate of 3X10 6 s -1 , this algorithm is superior to FFTW in time-consumption and can meet the real-time requirement of frequency spectrum analysis. (authors)

  3. ATALANTA: a multicomponent pulsed neutron diffraction analysis code

    International Nuclear Information System (INIS)

    Benham, M.J.; Ross, D.K.

    1986-01-01

    The analysis of powder diffraction patterns from metal hydrogen systems present certain problems which have been addressed in a restructured profile analysis program. The heart of this program, ATALANTA, is a routine which locates and processes small sections of the data field to which a minimal number of Bragg peaks contribute intensity. The analysis of a three component test data set is presented in order to demonstrate the method. (author)

  4. Analysis on working pressure selection of ACME integral test facility

    International Nuclear Information System (INIS)

    Chen Lian; Chang Huajian; Li Yuquan; Ye Zishen; Qin Benke

    2011-01-01

    An integral effects test facility, advanced core cooling mechanism experiment facility (ACME) was designed to verify the performance of the passive safety system and validate its safety analysis codes of a pressurized water reactor power plant. Three test facilities for AP1000 design were introduced and review was given. The problems resulted from the different working pressures of its test facilities were analyzed. Then a detailed description was presented on the working pressure selection of ACME facility as well as its characteristics. And the approach of establishing desired testing initial condition was discussed. The selected 9.3 MPa working pressure covered almost all important passive safety system enables the ACME to simulate the LOCAs with the same pressure and property similitude as the prototype. It's expected that the ACME design would be an advanced core cooling integral test facility design. (authors)

  5. Analysis of rod drop and pulsed source measurements of reactivity in the Winfrith SGHWR

    International Nuclear Information System (INIS)

    Brittain, I.

    1970-05-01

    Reactivity measurements by the rod-drop and pulsed source methods in the Winfrith SGHWR are seriously affected by spatial harmonics. A method of calculation is described which enables the spatial harmonics to be calculated in non-uniform cores in two or three dimensions, and thus allows a much more rigorous analysis of the experimental results than the usual point model. The method is used to analyse all the rod-drop measurements made during commissioning of the Winfrith SGHWR, and to comment on the results of pulsed source measurements. The reactivity worths of banks of ten and twelve shut-down tubes deduced from rod-drop and pulsed source experiments are in satisfactory agreement with each other and also with AIMAZ calculated values. The ability to calculate higher spatial harmonics in nonuniform cores is thought to be new, and may have a wider application to reactor kinetics through the method of Modal Analysis. (author)

  6. Stress-strain state analysis and optimization of rod system under periodic pulse load

    Directory of Open Access Journals (Sweden)

    Grebenyuk Grigory

    2018-01-01

    Full Text Available The paper considers the problem of analysis and optimization of rod systems subjected to combined static and periodic pulse load. As a result of the study the analysis method was developed based on traditional approach to solving homogeneous matrix equations of state and a special algorithm for developing a particular solution. The influence of pulse parameters variations on stress-strain state of a rod system was analyzed. Algorithms for rod systems optimization were developed basing on strength recalculation and statement and solution of optimization problem as a problem of nonlinear mathematical programming. Recommendations are developed for efficient organization of process for optimization of rod systems under static and periodic pulse load.

  7. Use of a prototype pulse oximeter for time series analysis of heart rate variability

    Science.gov (United States)

    González, Erika; López, Jehú; Hautefeuille, Mathieu; Velázquez, Víctor; Del Moral, Jésica

    2015-05-01

    This work presents the development of a low cost pulse oximeter prototype consisting of pulsed red and infrared commercial LEDs and a broad spectral photodetector used to register time series of heart rate and oxygen saturation of blood. This platform, besides providing these values, like any other pulse oximeter, processes the signals to compute a power spectrum analysis of the patient heart rate variability in real time and, additionally, the device allows access to all raw and analyzed data if databases construction is required or another kind of further analysis is desired. Since the prototype is capable of acquiring data for long periods of time, it is suitable for collecting data in real life activities, enabling the development of future wearable applications.

  8. Processing of pulse oximeter data using discrete wavelet analysis.

    Science.gov (United States)

    Lee, Seungjoon; Ibey, Bennett L; Xu, Weijian; Wilson, Mark A; Ericson, M Nance; Coté, Gerard L

    2005-07-01

    A wavelet-based signal processing technique was employed to improve an implantable blood perfusion monitoring system. Data was acquired from both in vitro and in vivo sources: a perfusion model and the proximal jejunum of an adult pig. Results showed that wavelet analysis could isolate perfusion signals from raw, periodic, in vitro data as well as fast Fourier transform (FFT) methods. However, for the quasi-periodic in vivo data segments, wavelet analysis provided more consistent results than the FFT analysis for data segments of 50, 10, and 5 s in length. Wavelet analysis has thus been shown to require less data points for quasi-periodic data than FFT analysis making it a good choice for an indwelling perfusion monitor where power consumption and reaction time are paramount.

  9. Fourier series analysis of a cylindrical pressure vessel subjected to axial end load and external pressure

    International Nuclear Information System (INIS)

    Brar, Gurinder Singh; Hari, Yogeshwar; Williams, Dennis K.

    2013-01-01

    Pressure Vessel Code, Section VIII, Division 2 and ASME STS-1. -- Highlights: • Fourier series is used to predict the load carrying capacity of cylindrical vessel. • Reliability approach used for analysis as against the deterministic approach. • Cylindrical pressure vessel is subjected to axial end load and external pressure. • Axisymmetric and asymmetric analysis carried out for imperfect pressure vessels. • Results are compared to the recommendations laid out in ASME B and PV Code

  10. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    International Nuclear Information System (INIS)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-01-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC) n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC) n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  11. Estimation of Pulse Transit Time as a Function of Blood Pressure Using a Nonlinear Arterial Tube-Load Model.

    Science.gov (United States)

    Gao, Mingwu; Cheng, Hao-Min; Sung, Shih-Hsien; Chen, Chen-Huan; Olivier, Nicholas Bari; Mukkamala, Ramakrishna

    2017-07-01

    pulse transit time (PTT) varies with blood pressure (BP) throughout the cardiac cycle, yet, because of wave reflection, only one PTT value at the diastolic BP level is conventionally estimated from proximal and distal BP waveforms. The objective was to establish a technique to estimate multiple PTT values at different BP levels in the cardiac cycle. a technique was developed for estimating PTT as a function of BP (to indicate the PTT value for every BP level) from proximal and distal BP waveforms. First, a mathematical transformation from one waveform to the other is defined in terms of the parameters of a nonlinear arterial tube-load model accounting for BP-dependent arterial compliance and wave reflection. Then, the parameters are estimated by optimally fitting the waveforms to each other via the model-based transformation. Finally, PTT as a function of BP is specified by the parameters. The technique was assessed in animals and patients in several ways including the ability of its estimated PTT-BP function to serve as a subject-specific curve for calibrating PTT to BP. the calibration curve derived by the technique during a baseline period yielded bias and precision errors in mean BP of 5.1 ± 0.9 and 6.6 ± 1.0 mmHg, respectively, during hemodynamic interventions that varied mean BP widely. the new technique may permit, for the first time, estimation of PTT values throughout the cardiac cycle from proximal and distal waveforms. the technique could potentially be applied to improve arterial stiffness monitoring and help realize cuff-less BP monitoring.

  12. Suitability of orthodontic brackets for rebonding and reworking following removal by air pressure pulses and conventional debracketing techniques.

    Science.gov (United States)

    Knösel, Michael; Mattysek, Simone; Jung, Klaus; Kubein-Meesenburg, Dietmar; Sadat-Khonsari, Reza; Ziebolz, Dirk

    2010-07-01

    To test the null hypothesis that there are no significant differences in the reusability of debonded brackets with regard to debonding technique and adhesive used. Ninety-six osteotomed third molars were randomly assigned to two study groups (n = 48) for bonding of a 0.018-inch bracket (Ormesh, Ormco) with either a composite adhesive (Mono-Lok2; RMO) or a glass ionomer cement (GIC; Fuji Ortho LC;GC). Each of these two groups were then randomly divided into four subgroups (n = 12) according to the method of debonding using (1) bracket removal pliers (BRP; Dentaurum), (2) a side cutter (SC; Dentaurum), (3) a lift-off debracketing instrument (LODI; 3M-Unitek), or (4) an air pressure pulse device (CoronaFlex; KaVo). The brackets were subsequently assessed visually for reusability and reworkability with 2x magnification and by pull testing with a 0.017- x 0.025-inch steel archwire. The proportions of reusable brackets were individually compared in terms of mode of removal and with regard to adhesives using the Fisher exact test (alpha = 5%). The null hypothesis was rejected. Not taking into account the debonding method, brackets bonded with GIC were judged to a significant extent (81%; n = 39; P < .01) to be reworkable compared with those bonded with composite (56%; n = 27). All brackets in both adhesive groups removed with either the LODI or the CoronaFlex were found to be reusable, whereas 79% (46%) of the brackets removed with the BRP (SC) were not. The proportion of reusable brackets differed significantly between modes of removal (P < .01). With regard to bracket reusability, the SC and the BRP cannot be recommended for debonding brackets, especially in combination with a composite adhesive.

  13. Diagnostics of atmospheric-pressure pulsed-dc discharge with metal and liquid anodes by multiple laser-aided methods

    Science.gov (United States)

    Urabe, Keiichiro; Shirai, Naoki; Tomita, Kentaro; Akiyama, Tsuyoshi; Murakami, Tomoyuki

    2016-08-01

    The density and temperature of electrons and key heavy particles were measured in an atmospheric-pressure pulsed-dc helium discharge plasma with a nitrogen molecular impurity generated using system with a liquid or metal anode and a metal cathode. To obtain these parameters, we conducted experiments using several laser-aided methods: Thomson scattering spectroscopy to obtain the spatial profiles of electron density and temperature, Raman scattering spectroscopy to obtain the neutral molecular nitrogen rotational temperature, phase-modulated dispersion interferometry to determine the temporal variation of the electron density, and time-resolved laser absorption spectroscopy to analyze the temporal variation of the helium metastable atom density. The electron density and temperature measured by Thomson scattering varied from 2.4  ×  1014 cm-3 and 1.8 eV at the center of the discharge to 0.8  ×  1014 cm-3 and 1.5 eV near the outer edge of the plasma in the case of the metal anode, respectively. The electron density obtained with the liquid anode was approximately 20% smaller than that obtained with the metal anode, while the electron temperature was not significantly affected by the anode material. The molecular nitrogen rotational temperatures were 1200 K with the metal anode and 1650 K with the liquid anode at the outer edge of the plasma column. The density of helium metastable atoms decreased by a factor of two when using the liquid anode.

  14. Smoking Cessation Ameliorates Microalbuminuria With Reduction of Blood Pressure and Pulse Rate in Patients With Already Diagnosed Diabetes Mellitus.

    Science.gov (United States)

    Hieshima, Kunio; Suzuki, Tomoko; Sugiyama, Seigo; Kurinami, Noboru; Yoshida, Akira; Miyamoto, Fumio; Kajiwara, Keizo; Jinnouchi, Tomio; Jinnouchi, Hideaki

    2018-06-01

    Smoking cessation in newly diagnosed type 2 diabetes patients is reported to be associated with amelioration of metabolic parameters and blood pressure (BP), and the reduction of microalbuminuria. The aim of this study is to demonstrate changes in BP, pulse rate (PR), and microalbuminuria in already diagnosed diabetes patients who quit smoking. We retrospectively evaluated diabetes outpatients who were habitual smokers, and who visited to our smoking cessation clinic. Patients were divided into two groups based on their smoking status at the termination of a 3-month smoking cessation program (smoking cessation group and smoking group), and analyzed systolic and diastolic BPs, PR, HbA1c, and body weight at the start date, and at 1, 3, 6, and 12 months thereafter. The urinary albumin-to-creatinine ratio was also measured at the start date and at 12 months. Thirty-five patients met our criteria. Mean diabetes duration was 12 years. Eighteen patients (52%) quit smoking. Success or failure of smoking cessation depended on nicotine dependence rather than good or bad glycemic control. Both BP and PR decreased significantly after 1 month or later in the smoking cessation group without worsening HbA1c, while both parameters did not show any changes in the smoking group. Microalbuminuria was also ameliorated significantly at 12 months compared with that at the start date in the smoking cessation group (95.8 ± 92.9 mg/gCr vs. 75.5 ± 96.3 mg/gCr, P = 0.0059), while it did not show a significant change in the smoking group. (61.9 ± 43.5 mg/gCr vs. 97.7 ± 90.4 mg/gCr, P = 0.1039). Smoking cessation might cause a reduction in chronic kidney disease progression through ameliorating microalbuminuria without metabolic adverse effects in patients already diagnosed with diabetes mellitus.

  15. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    Science.gov (United States)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-06-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called "interphase" between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC-TiC)n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC-TiC)n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  16. Amlodipine+benazepril is superior to hydrochlorothiazide+benazepril irrespective of baseline pulse pressure: subanalysis of the ACCOMPLISH trial.

    Science.gov (United States)

    Skoglund, Per H; Svensson, Per; Asp, Joline; Dahlöf, Björn; Kjeldsen, Sverre E; Jamerson, Kenneth A; Weber, Michael A; Jia, Yan; Zappe, Dion H; Östergren, Jan

    2015-02-01

    Pulse pressure (PP) is an independent risk factor for cardiovascular (CV) disease and death but few studies have investigated the effect of antihypertensive treatments in relation to PP levels before treatment. The Avoiding Cardiovascular Events Through Combination Therapy in Patients Living With Systolic Hypertension (ACCOMPLISH) trial showed that the combination of benazepril+amlodipine (B+A) is superior to benazepril+hydrochlorothiazide (B+H) in reducing CV events. We aimed to investigate whether the treatment effects in the ACCOMPLISH trial were dependent on baseline PP. High-risk hypertensive patients (n=11,499) were randomized to double-blinded treatment with single-pill combinations of either B+A or B+H and followed for 36 months. Patients were divided into tertiles according to their baseline PP and events (CV mortality/myocardial infarction or stroke) were compared. Hazard ratios (HRs) for the treatment effect (B+A over B+H) were calculated in a Cox regression model with age, coronary artery disease, and diabetes mellitus as covariates and were compared across the tertiles. The event rate was increased in the high tertile of PP compared with the low tertile (7.2% vs 4.4% P<.01). In the high and medium PP tertiles, HRs were 0.75 (95% confidence interval [CI], 0.60-0.95; P=.018) and 0.74 (CI, 0.56-0.98, P=.034), respectively, in favor of B+A. There was no significant difference between the treatments in the low tertile and no significant differences in treatment effect when comparing the HRs between tertiles of PP. B+A has superior CV protection over B+H in high-risk hypertensive patients independent of baseline PP although the absolute treatment effect is enhanced in the higher tertiles of PP where event rates are higher. © 2014 Wiley Periodicals, Inc.

  17. Study of continuous blood pressure estimation based on pulse transit time, heart rate and photoplethysmography-derived hemodynamic covariates.

    Science.gov (United States)

    Feng, Jingjie; Huang, Zhongyi; Zhou, Congcong; Ye, Xuesong

    2018-06-01

    It is widely recognized that pulse transit time (PTT) can track blood pressure (BP) over short periods of time, and hemodynamic covariates such as heart rate, stiffness index may also contribute to BP monitoring. In this paper, we derived a proportional relationship between BP and PPT -2 and proposed an improved method adopting hemodynamic covariates in addition to PTT for continuous BP estimation. We divided 28 subjects from the Multi-parameter Intelligent Monitoring for Intensive Care database into two groups (with/without cardiovascular diseases) and utilized a machine learning strategy based on regularized linear regression (RLR) to construct BP models with different covariates for corresponding groups. RLR was performed for individuals as the initial calibration, while recursive least square algorithm was employed for the re-calibration. The results showed that errors of BP estimation by our method stayed within the Association of Advancement of Medical Instrumentation limits (- 0.98 ± 6.00 mmHg @ SBP, 0.02 ± 4.98 mmHg @ DBP) when the calibration interval extended to 1200-beat cardiac cycles. In comparison with other two representative studies, Chen's method kept accurate (0.32 ± 6.74 mmHg @ SBP, 0.94 ± 5.37 mmHg @ DBP) using a 400-beat calibration interval, while Poon's failed (- 1.97 ± 10.59 mmHg @ SBP, 0.70 ± 4.10 mmHg @ DBP) when using a 200-beat calibration interval. With additional hemodynamic covariates utilized, our method improved the accuracy of PTT-based BP estimation, decreased the calibration frequency and had the potential for better continuous BP estimation.

  18. Thrombogenicity and central pulse pressure to enhance prediction of ischemic event occurrence in patients with established coronary artery disease: The MAGMA-ischemia score.

    Science.gov (United States)

    Bliden, Kevin P; Chaudhary, Rahul; Navarese, Eliano P; Sharma, Tushar; Kaza, Himabindu; Tantry, Udaya S; Gurbel, Paul A

    2018-01-01

    Conventional cardiovascular risk estimators based on clinical demographics have limited prediction of coronary events. Markers for thrombogenicity and vascular function have not been explored in risk estimation of high-risk patients with coronary artery disease. We aimed to develop a clinical and biomarker score to predict 3-year adverse cardiovascular events. Four hundred eleven patients, with ejection fraction ≥40% undergoing coronary angiography, and found to have a luminal diameter stenosis ≥50%, were included in the analysis. Thrombelastography indices and central pulse pressure (CPP) were determined at the time of catheterization. We identified predictors of death, myocardial infarction (MI) or stroke and developed a numerical ischemia risk score. The primary endpoint of cardiovascular death, MI or stroke occurred in 22 patients (5.4%). The factors associated with events were age, prior PCI or CABG, diabetes, CPP, and thrombin-induced platelet-fibrin clot strength, and were included in the MAGMA-ischemia score. The MAGMA-ischemia score showed a c-statistic of 0.85 (95% Confidence Interval [CI] 0.80-0.87; pMAGMA-ischemia score greater than 5 had highest risk to develop clinical events, hazard ratio for the primary endpoint: 13.9 (95% CI 5.8-33.1, pMAGMA-ischemia score yielded a higher discrimination. Inclusion of CPP and assessment of thrombogenicity in a novel score for patients with documented CAD enhanced the prediction of events. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Association between the severity of coronary artery stenosis and the combination of the difference in blood pressure between arms and brachial-ankle pulse wave velocity.

    Science.gov (United States)

    Miyase, Yuiko; Miura, Shin-Ichiro; Shiga, Yuhei; Yano, Masaya; Suematsu, Yasunori; Adachi, Sen; Norimatsu, Kenji; Nakamura, Ayumi; Saku, Keijiro

    2016-01-01

    A difference in systolic blood pressure (SBP) ≥10 mmHg between the arms is associated with an increased risk of coronary artery disease (CAD) and mortality in high-risk patients. Four hundred and fourteen patients were divided into three groups according to the percent most severe luminal narrowing of a coronary artery as diagnosed by coronary computed tomography angiography: no or mild coronary stenosis (0-49%), moderate stenosis (50-69%) and severe stenosis (≥70%) groups. The relative difference in SBP between arms in the severe group was significantly lower than those in the no or mild and moderate groups. The brachial-ankle pulse wave velocity (baPWV) significantly increased as the severity of coronary stenosis increased. We confirmed that severe coronary stenosis was independently associated with both the relative difference in SBP between arms and baPWV, in addition to age, gender, hypertension, dyslipidemia, diabetes mellitus and ankle-brachial index by a logistic regression analysis. The group with a relative difference in SBP between arms of difference in SBP between arms and baPWV may be a more effective approach for the non-invasive assessment of the severity of CAD.

  20. Pressure Control in Distillation Columns: A Model-Based Analysis

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Bisgaard, Thomas; Kristensen, Henrik

    2014-01-01

    A comprehensive assessment of pressure control in distillation columns is presented, including the consequences for composition control and energy consumption. Two types of representative control structures are modeled, analyzed, and benchmarked. A detailed simulation test, based on a real...... industrial distillation column, is used to assess the differences between the two control structures and to demonstrate the benefits of pressure control in the operation. In the second part of the article, a thermodynamic analysis is carried out to establish the influence of pressure on relative volatility...

  1. Measurement of the C{sub 2}H{sub 2} destruction kinetics by infrared laser absorption spectroscopy in a pulsed low pressure dc discharge

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, A [LPTP, Ecole Polytechnique, CNRS, Route de Saclay, 91 128 Palaiseau Cedex (France); Guaitella, O [LPTP, Ecole Polytechnique, CNRS, Route de Saclay, 91 128 Palaiseau Cedex (France); Gatilova, L [LPTP, Ecole Polytechnique, CNRS, Route de Saclay, 91 128 Palaiseau Cedex (France); Hannemann, M [INP-Greifswald, Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald (Germany); Roepcke, J [INP-Greifswald, Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald (Germany)

    2007-04-07

    The kinetics of destruction of C{sub 2}H{sub 2} is investigated in a low pressure pulsed dc discharge in dry air. Tuneable diode laser absorption spectroscopy in the mid-infrared region (1350 cm{sup -1}) has been used to measure the influence of (i) the pulse duration (ii) the pulse repetition rate and (iii) the pulse current on the C{sub 2}H{sub 2} concentration in situ the discharge tube. First, it is shown that in the plasma region under flow conditions the time averaged concentration of C{sub 2}H{sub 2} depends only on the time averaged discharge current. Second, time resolved measurements have been performed in a closed reactor, i.e. under static conditions. A simple kinetic modelling of the pulsed discharge leads to a good agreement with the experimental results and shows that the oxidation rate of C{sub 2}H{sub 2} is mainly controlled by the time averaged concentration of O atoms. Finally, the influence of porous TiO{sub 2} photocatalyst on the C{sub 2}H{sub 2} oxidation rate is reported.

  2. Measurement of the C2H2 destruction kinetics by infrared laser absorption spectroscopy in a pulsed low pressure dc discharge

    International Nuclear Information System (INIS)

    Rousseau, A; Guaitella, O; Gatilova, L; Hannemann, M; Roepcke, J

    2007-01-01

    The kinetics of destruction of C 2 H 2 is investigated in a low pressure pulsed dc discharge in dry air. Tuneable diode laser absorption spectroscopy in the mid-infrared region (1350 cm -1 ) has been used to measure the influence of (i) the pulse duration (ii) the pulse repetition rate and (iii) the pulse current on the C 2 H 2 concentration in situ the discharge tube. First, it is shown that in the plasma region under flow conditions the time averaged concentration of C 2 H 2 depends only on the time averaged discharge current. Second, time resolved measurements have been performed in a closed reactor, i.e. under static conditions. A simple kinetic modelling of the pulsed discharge leads to a good agreement with the experimental results and shows that the oxidation rate of C 2 H 2 is mainly controlled by the time averaged concentration of O atoms. Finally, the influence of porous TiO 2 photocatalyst on the C 2 H 2 oxidation rate is reported

  3. Recommended practice for process sampling for partial pressure analysis

    International Nuclear Information System (INIS)

    Blessing, James E.; Ellefson, Robert E.; Raby, Bruce A.; Brucker, Gerardo A.; Waits, Robert K.

    2007-01-01

    This Recommended Practice describes and recommends various procedures and types of apparatus for obtaining representative samples of process gases from >10 -2 Pa (10 -4 Torr) for partial pressure analysis using a mass spectrometer. The document was prepared by a subcommittee of the Recommended Practices Committee of the American Vacuum Society. The subcommittee was comprised of vacuum users and manufacturers of mass spectrometer partial pressure analyzers who have practical experience in the sampling of process gas atmospheres

  4. The influence of substrate temperature and deposition pressure on pulsed laser deposited thin films of CaS:Eu{sup 2+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Nyenge, R.L. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Physics Department, Kenyatta University, P.O. Box 43844-0100, Nairobi (Kenya); Swart, H.C. [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa); Ntwaeaborwa, O.M., E-mail: ntwaeab@ufs.ac.za [Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA9300 (South Africa)

    2016-01-01

    The aim of this study was to investigate the influence of substrate temperature and argon deposition pressure on the structure, morphology and photoluminescence emission (PL) properties of pulsed laser deposited thin films of CaS:Eu{sup 2+}. The PL intensity improved significantly upon reaching substrate temperature of 650 °C. The (200) peak gradually became the preferred orientation. The increase in PL intensity as well as surface roughness is attributed to improved crystallinity and higher growth rates, respectively. The best PL intensity as a function of deposition pressure was obtained at an argon pressure of 80 mTorr. The initial increase and eventual drop in PL intensity as deposition pressure increases is ascribed to the changes in growth rates.

  5. Development of the vacuum system pressure responce analysis code PRAC

    International Nuclear Information System (INIS)

    Horie, Tomoyoshi; Kawasaki, Kouzou; Noshiroya, Shyoji; Koizumi, Jun-ichi.

    1985-03-01

    In this report, we show the method and numerical results of the vacuum system pressure responce analysis code. Since fusion apparatus is made up of many vacuum components, it is required to analyze pressure responce at any points of the system when vacuum system is designed or evaluated. For that purpose evaluating by theoretical solution is insufficient. Numerical analysis procedure such as finite difference method is usefull. In the PRAC code (Pressure Responce Analysis Code), pressure responce is obtained solving derivative equations which is obtained from the equilibrium relation of throughputs and contain the time derivative of pressure. As it considers both molecular and viscous flows, the coefficients of the equation depend on the pressure and the equations become non-linear. This non-linearity is treated as piece-wise linear within each time step. Verification of the code is performed for the simple problems. The agreement between numerical and theoretical solutions is good. To compare with the measured results, complicated model of gas puffing system is analyzed. The agreement is well for practical use. This code will be a useful analytical tool for designing and evaluating vacuum systems such as fusion apparatus. (author)

  6. Structural analysis and evaluation for the design of pressure vessel

    International Nuclear Information System (INIS)

    Arai, K.; Uragami, K.; Funada, T.; Baba, K.; Kira, T.

    1977-01-01

    For the design of pressure vessel, the detailed structural analysis such as the fatigue analysis under operating conditions is required by ASME Code or Japanese regulation. Accordingly, it should be verified by the analysis that the design of the pressure vessel is in compliance with the stress limitation defined in the Code or the regulation. However, it was apparent that the analysis is very complicated and takes a lot of time to evaluate in accordance with the Code requirements. Thereupon we developed the computer program by which we can perform the stress analysis with correctness and comparatively in a short period of design work reflecting the calculation results on detailed drawings to be used for fabrication. The computer program is controlled in combination with the system of the design work and out put list of the program can be directly used for the stress analysis report which is issued to customers. In addition to the above computer program, we developed the specific three dimensional finite element computer program to make sure of the structural integrity of the vessel head and flanges which are most complex for the analysis compared with the stress distribution measured by strain gauges on the vessel head and flange. Besides the structural analysis, the fracture mechanics analysis for the purpose of preventing the pressure vessel from the brittle fracture during heat-up and cool-down operation is also important and thereby we showed herein that the pressure vessel is in safety against the brittle fracture for the specified operating conditions. As a result of the above-mentioned analysis, the pressure vessel is designed with safety from the stand-points of the structural intensity and the fracture mechanics. (auth.)

  7. Organization of pulse-height analysis programs for high event rates

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, C E [Argonne National Lab., Ill. (USA)

    1976-09-01

    The ability of a pulse-height analysis program to handle high event rates can be enhanced by organizing it so as to minimize the time spent in interrupt housekeeping. Specifically, the routine that services the data-ready interrupt from the ADC should test whether another event is ready before performing the interrupt return.

  8. Application of dimensional analysis to ozone production by pulsed streamer discharge in oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Buntat, Z; Harry, J E; Smith, I R [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

    2003-07-07

    This paper describes the use of dimensional analysis in investigating the effects of the electrical and the discharge configuration parameters on ozone production in oxygen, by means of a pulsed streamer discharge. Ozone destruction factors are taken into account in the model, and predicted results are shown to be in good agreement with experimental findings.

  9. Neutron-gamma discrimination by pulse analysis with superheated drop detector

    International Nuclear Information System (INIS)

    Das, Mala; Seth, S.; Saha, S.; Bhattacharya, S.; Bhattacharjee, P.

    2010-01-01

    Superheated drop detector (SDD) consisting of drops of superheated liquid of halocarbon is irradiated to neutrons and gamma-rays from 252 Cf fission neutron source and 137 Cs gamma source, respectively, separately. Analysis of pulse height of signals at the neutron and gamma-ray sensitive temperature provides significant information on the identification of neutron and gamma-ray induced events.

  10. Application of dimensional analysis to ozone production by pulsed streamer discharge in oxygen

    CERN Document Server

    Buntat, Z; Smith, I R

    2003-01-01

    This paper describes the use of dimensional analysis in investigating the effects of the electrical and the discharge configuration parameters on ozone production in oxygen, by means of a pulsed streamer discharge. Ozone destruction factors are taken into account in the model, and predicted results are shown to be in good agreement with experimental findings.

  11. Application of dimensional analysis to ozone production by pulsed streamer discharge in oxygen

    International Nuclear Information System (INIS)

    Buntat, Z; Harry, J E; Smith, I R

    2003-01-01

    This paper describes the use of dimensional analysis in investigating the effects of the electrical and the discharge configuration parameters on ozone production in oxygen, by means of a pulsed streamer discharge. Ozone destruction factors are taken into account in the model, and predicted results are shown to be in good agreement with experimental findings

  12. Application of dimensional analysis to ozone production by pulsed streamer discharge in oxygen

    Science.gov (United States)

    Buntat, Z.; Harry, J. E.; Smith, I. R.

    2003-07-01

    This paper describes the use of dimensional analysis in investigating the effects of the electrical and the discharge configuration parameters on ozone production in oxygen, by means of a pulsed streamer discharge. Ozone destruction factors are taken into account in the model, and predicted results are shown to be in good agreement with experimental findings.

  13. Cost analysis of commercial pasteurization of orange juice by pulsed electric fields

    Science.gov (United States)

    The cost of pulsed electric field (PEF) pasteurization of orange juice was estimated. The cost analysis was based on processing conditions that met the US FDA (5 log reduction) requirement for fruit juice pasteurization and that achieved a 2 month microbial shelf-life. PEF-treated samples processed ...

  14. A seismic analysis of the driving system for the pulsed reactor

    International Nuclear Information System (INIS)

    Hu Yongtao; Fu Shixiang; Zeng Jianhua; Hong Jingfeng

    1991-01-01

    The driving system of the pulsed reactor contains control rods, pulsing o rod and sample rack. They are slender, and their drive function is required more strictly. First, a complete model which contains all driving system and reactor bridge is used. Then the substructure models are adopted. The results of calculation are compared with the experimental results. It shows that the analysis results are reliable and the substructure method is simple, available and utility. The seismic safety is evaluated by the results from response spectra method

  15. Does chocolate reduce blood pressure? A meta-analysis

    Directory of Open Access Journals (Sweden)

    Ried Karin

    2010-06-01

    Full Text Available Abstract Background Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals. Methods We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive. Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P Results Fifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change ± SE: SBP: -3.2 ± 1.9 mmHg, P = 0.001; DBP: -2.0 ± 1.3 mmHg, P = 0.003. However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 ± 3.0 mmHg; P = 0.0009; DBP: -2.7 ± 2.2 mm Hg, P = 0.01, while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 ± 2.3 mmHg, P = 0.17; DBP: -1.3 ± 1.6 mmHg, P = 0.12. Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30

  16. OXYGEN PRESSURE REGULATOR DESIGN AND ANALYSIS THROUGH FINITE ELEMENT MODELING

    Directory of Open Access Journals (Sweden)

    Asterios KOSMARAS

    2017-05-01

    Full Text Available Oxygen production centers produce oxygen in high pressure that needs to be defused. A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. This study aims to design a new oxygen pressure regulator and perform an analysis using Finite Element Modeling in order to evaluate its working principle. In the design procedure,the main elements and the operating principles of a pressure regulator are taking into account. The regulator is designed and simulations take place in order to assessthe proposed design. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator.

  17. Advances in the analysis of pressure interference tests

    Energy Technology Data Exchange (ETDEWEB)

    Martinez R, N. [Petroleos Mexicanos, PEMEX, Mexico City (Mexico); Samaniego V, F. [Univ. Nacional Autonoma de Mexico (Mexico)

    2010-12-15

    This paper presented an extension for radial, linear, and spherical flow conditions of the El-Khatib method for analyzing pressure interference tests through utilization of the pressure derivative. Conventional analysis of interference tests considers only radial flow, but some reservoirs have physical field conditions in which linear or spherical flow conditions prevail. The INTERFERAN system, a friendly computer code for the automatic analysis of pressure interference tests, was also discussed and demonstrated by way of 2 field cases. INTERFERAN relies on the principle of superposition in time and space to interpret a test of several wells with variable histories of production or injection or both. The first field case addressed interference tests conducted in the naturally fractured geothermal field of Klamath Falls, and the second field case was conducted in a river-formed bed in which linear flow conditions are dominant. The analysis was deemed to be reliable. 13 refs., 1 tab., 7 figs.

  18. Probability analysis of MCO over-pressurization during staging

    International Nuclear Information System (INIS)

    Pajunen, A.L.

    1997-01-01

    The purpose of this calculation is to determine the probability of Multi-Canister Overpacks (MCOs) over-pressurizing during staging at the Canister Storage Building (CSB). Pressurization of an MCO during staging is dependent upon changes to the MCO gas temperature and the build-up of reaction products during the staging period. These effects are predominantly limited by the amount of water that remains in the MCO following cold vacuum drying that is available for reaction during staging conditions. Because of the potential for increased pressure within an MCO, provisions for a filtered pressure relief valve and rupture disk have been incorporated into the MCO design. This calculation provides an estimate of the frequency that an MCO will contain enough water to pressurize beyond the limits of these design features. The results of this calculation will be used in support of further safety analyses and operational planning efforts. Under the bounding steady state CSB condition assumed for this analysis, an MCO must contain less than 1.6 kg (3.7 lbm) of water available for reaction to preclude actuation of the pressure relief valve at 100 psid. To preclude actuation of the MCO rupture disk at 150 psid, an MCO must contain less than 2.5 kg (5.5 lbm) of water available for reaction. These limits are based on the assumption that hydrogen generated by uranium-water reactions is the sole source of gas produced within the MCO and that hydrates in fuel particulate are the primary source of water available for reactions during staging conditions. The results of this analysis conclude that the probability of the hydrate water content of an MCO exceeding 1.6 kg is 0.08 and the probability that it will exceed 2.5 kg is 0.01. This implies that approximately 32 of 400 staged MCOs may experience pressurization to the point where the pressure relief valve actuates. In the event that an MCO pressure relief valve fails to open, the probability is 1 in 100 that the MCO would experience

  19. Coupling analysis of the target temperature and thermal stress due to pulsed ion beam

    International Nuclear Information System (INIS)

    Yan Jie; Liu Meng; Lin Jufang; An Li; Long Xinggui

    2013-01-01

    Background: Target temperature has an important effect on the target life for the sealed neutron generator without cooling system. Purpose: To carry out the thermal-mechanical coupling analysis of the film-substrate target bombarded by the pulsed ion beam. Methods: The indirect coupling Finite Element Method (FEM) with a 2-dimensional time-space Gaussian axisymmetric power density as heat source was used to simulate the target temperature and thermal stress fields. Results: The effects of the target temperature and thermal stress fields under difference pulse widths and beam sizes were analyzed in terms of the FEM results. Conclusions: Combining with the temperature requirement and the thermal stress inducing film thermal mechanical destruction effect of the sealed neutron generator film-substrate targets, an optimized pulsed ion beam work status was proposed. (authors)

  20. Fluorescence decay data analysis correcting for detector pulse pile-up at very high count rates

    Science.gov (United States)

    Patting, Matthias; Reisch, Paja; Sackrow, Marcus; Dowler, Rhys; Koenig, Marcelle; Wahl, Michael

    2018-03-01

    Using time-correlated single photon counting for the purpose of fluorescence lifetime measurements is usually limited in speed due to pile-up. With modern instrumentation, this limitation can be lifted significantly, but some artifacts due to frequent merging of closely spaced detector pulses (detector pulse pile-up) remain an issue to be addressed. We propose a data analysis method correcting for this type of artifact and the resulting systematic errors. It physically models the photon losses due to detector pulse pile-up and incorporates the loss in the decay fit model employed to obtain fluorescence lifetimes and relative amplitudes of the decay components. Comparison of results with and without this correction shows a significant reduction of systematic errors at count rates approaching the excitation rate. This allows quantitatively accurate fluorescence lifetime imaging at very high frame rates.

  1. Background reduction and noise discrimination in the proportional counting of tritium using pulse-shape analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hochel, R C; Hayes, D W [Du Pont de Nemours (E.I.) and Co., Aiken, S.C. (USA). Savannah River Lab.

    1975-12-01

    A pulse-shape analysis (PSA) unit of commercial design has been incorporated into a proportional counting system to determine the effectiveness of pulse-shape discrimination in increasing the sensitivity of tritium counting. It was found that a quantitative determination of tritium could be obtained directly from the PSA time spectrum eliminating the need for beta-ray energy selection used in the pulse-shape discrimination (PSD) technique. The performance of the proportional counting system was tested using the PSA unit and anticoincidence shielding, both singly and combined, under several types of background. A background reduction factor of 169 was obtained from the combined PSA-anticoincidence system with only a 2% loss in tritium counting efficiency. The PSA method was also found to offer significant reductions in noise background.

  2. Background reduction and noise discrimination in the proportional counting of tritium using pulse-shape analysis

    International Nuclear Information System (INIS)

    Hochel, R.C.; Hayes, D.W.

    1975-01-01

    A pulse-shape analysis (PSA) unit of commercial design has been incorporated into a proportional counting system to determine the effectiveness of pulse-shape discrimination in increasing the sensitivity of tritium counting. It was found that a quantitative determination of tritium could be obtained directly from the PSA time spectrum eliminating the need for beta-ray energy selection used in the pulse-shape discrimination (PSD) technique. The performance of the proportional counting system was tested using the PSA unit and anticoincidence shielding, both singly and combined, under several types of background. A background reduction factor of 169 was obtained from the combined PSA-anticoincidence system with only a 2% loss in tritium counting efficiency. The PSA method was also found to offer significant reductions in noise background. (Auth.)

  3. Feasibility analysis for attosecond X-ray pulses at FERMI@ELETTRA free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, Alexander

    2004-09-01

    We present preliminary analysis for the feasibility of the attosecond x-ray pulses at a proposed FERMI@ELETTRA free electron laser (FEL) [1]. In part 1 we restrict ourselves to minimal modifications to the proposed FEL and consider a scheme for attosecond x-ray production which can be qualified as a small add-on to a primary facility. We demonstrate that at 5-nm wavelength our scheme is capable for production of pulses with an approximate duration of 100 attoseconds at approximately 2 MW peak power and with an absolute temporal synchronization to a pump laser pulse. In part 2 we propose to use an FEL amplifier seeded by a VUV signal and to follow it by the scheme for attosecond x-ray production described in part 1.

  4. Data processing for the multichannel pulse height analysis system ND-50/50, (1)

    International Nuclear Information System (INIS)

    Katagiri, Masaki

    1977-03-01

    The multichannel pulse height analysis system ND-50/50 manufactured by Nuclear Data Inc. consists of a 4096 channel pulse height analyzer and a small computer PDP-8/L (Digital Equipment Corporation). A conversational interpretive language, MACAL (Multichannel Analyzer CALculator) has been developed to analyze gamma-ray spectra in ND-50/50. It is a modification of the FOCAL (FOrmula CALculator) language of Digital Equipment Corporation. MACAL consists of imperative English commands and mathematical expressions, and has standard mathematical functions and functions for controlling the multichannel pulse height analyzer and I/O devices (high-speed reader, high-speed punch, and digital plotter). With MACAL, the following five programs were prepared : 1) program for controlling the multichannel pulse height analyzer and data handling, 2) program for automatically analyzing gamma-ray spectra obtained by germanium detectors, 3) program for automatically measuring characteristics of germanium detectors, 4) program for calculating the center energy of gamma-ray peaks, and 5) program for plotting the pulse height distribution and diagraming the results obtained with the programs. By combining the programs according to experimental purposes, the system can be highly effective. (auth.)

  5. Derivation and analysis of the Feynman-alpha formula for deterministically pulsed sources

    International Nuclear Information System (INIS)

    Wright, J.; Pazsit, I.

    2004-03-01

    The purpose or this report is to give a detailed description of the calculation of the Feynman-alpha formula with deterministically pulsed sources. In contrast to previous calculations, Laplace transform and complex function methods are used to arrive at a compact solution in form of a Fourier series-like expansion. The advantage of this method is that it is capable to treat various pulse shapes. In particular, in addition to square- and Dirac delta pulses, a more realistic Gauss-shaped pulse is also considered here. The final solution of the modified variance-to-mean, that is the Feynman Y(t) function, can be quantitatively evaluated fast and with little computational effort. The analytical solutions obtained are then analysed quantitatively. The behaviour of the number or neutrons in the system is investigated in detail, together with the transient that follows the switching on of the source. An analysis of the behaviour of the Feynman Y(t) function was made with respect to the pulse width and repetition frequency. Lastly, the possibility of using me formulae for the extraction of the parameter alpha from a simulated measurement is also investigated

  6. X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

    International Nuclear Information System (INIS)

    Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong; Tarasenko, Victor; Kostyrya, Igor D.; Ma Hao; Yan Ping

    2012-01-01

    This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30–40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

  7. Pressure Systems Stored-Energy Threshold Risk Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Paulsen, Samuel S.

    2009-08-25

    Federal Regulation 10 CFR 851, which became effective February 2007, brought to light potential weaknesses regarding the Pressure Safety Program at the Pacific Northwest National Laboratory (PNNL). The definition of a pressure system in 10 CFR 851 does not contain a limit based upon pressure or any other criteria. Therefore, the need for a method to determine an appropriate risk-based hazard level for pressure safety was identified. The Laboratory has historically used a stored energy of 1000 lbf-ft to define a pressure hazard; however, an analytical basis for this value had not been documented. This document establishes the technical basis by evaluating the use of stored energy as an appropriate criterion to establish a pressure hazard, exploring a suitable risk threshold for pressure hazards, and reviewing the methods used to determine stored energy. The literature review and technical analysis concludes the use of stored energy as a method for determining a potential risk, the 1000 lbf-ft threshold, and the methods used by PNNL to calculate stored energy are all appropriate. Recommendations for further program improvements are also discussed

  8. Pressurized thermal shock probabilistic fracture mechanics sensitivity analysis for Yankee Rowe reactor pressure vessel

    International Nuclear Information System (INIS)

    Dickson, T.L.; Cheverton, R.D.; Bryson, J.W.; Bass, B.R.; Shum, D.K.M.; Keeney, J.A.

    1993-08-01

    The Nuclear Regulatory Commission (NRC) requested Oak Ridge National Laboratory (ORNL) to perform a pressurized-thermal-shock (PTS) probabilistic fracture mechanics (PFM) sensitivity analysis for the Yankee Rowe reactor pressure vessel, for the fluences corresponding to the end of operating cycle 22, using a specific small-break-loss- of-coolant transient as the loading condition. Regions of the vessel with distinguishing features were to be treated individually -- upper axial weld, lower axial weld, circumferential weld, upper plate spot welds, upper plate regions between the spot welds, lower plate spot welds, and the lower plate regions between the spot welds. The fracture analysis methods used in the analysis of through-clad surface flaws were those contained in the established OCA-P computer code, which was developed during the Integrated Pressurized Thermal Shock (IPTS) Program. The NRC request specified that the OCA-P code be enhanced for this study to also calculate the conditional probabilities of failure for subclad flaws and embedded flaws. The results of this sensitivity analysis provide the NRC with (1) data that could be used to assess the relative influence of a number of key input parameters in the Yankee Rowe PTS analysis and (2) data that can be used for readily determining the probability of vessel failure once a more accurate indication of vessel embrittlement becomes available. This report is designated as HSST report No. 117

  9. Thermogravimetric analysis and dissociation pressure of caesium trihalides

    International Nuclear Information System (INIS)

    Harris, G.S.; McKechnie, J.S.

    1982-01-01

    We have carried out a thermogravimetric study of caesium trihalides to obtain, from the procedural decomposition temperatures, an order of apparent thermal stability which could be compared with the order of thermodynamic stability obtained from vapour pressure measurements. Thermogravimetric analysis could also prove to be a useful method for rapid analysis of metal polyhalides. The thermograms indicated a one-step decomposition for each compound; the procedural decomposition temperatures and percentage weight losses obtained are given. Dissociation pressures were measured and values of equilibrium constant and enthalpy of dissociation were calculated. The results are given. The 'stability' order obtained is discussed. (U.K.)

  10. Analysis of Pressure Variations in a Low-Pressure Nickel-Hydrogen Battery - Part 1.

    Science.gov (United States)

    Purushothaman, B K; Wainright, J S

    2012-05-15

    A low pressure nickel-hydrogen battery using either a metal hydride or gaseous hydrogen for H(2) storage has been developed for use in implantable neuroprosthetic devices. In this paper, pressure variations inside the cell for the gaseous hydrogen version are analyzed and correlated with oxygen evolution side reaction at the end of charging, the recombination of oxygen with hydrogen during charging and a subsequent rest period, and the self-discharge of the nickel electrode. About 70% of the recombination occurred simultaneously with oxygen evolution during charging and the remaining oxygen recombined with hydrogen during the 1(st) hour after charging. Self-discharge of the cell varies linearly with hydrogen pressure at a given state of charge and increased with increasing battery charge levels. The coulometric efficiency calculated based on analysis of the pressure-time data agreed well with the efficiency calculated based on the current-time data. Pressure variations in the battery are simulated accurately to predict coulometric efficiency and the state of charge of the cell, factors of extreme importance for a battery intended for implantation within the human body.

  11. Analysis of Pressure Variations in a Low-Pressure Nickel-Hydrogen Battery – Part 1

    Science.gov (United States)

    Purushothaman, B. K.; Wainright, J. S.

    2012-01-01

    A low pressure nickel-hydrogen battery using either a metal hydride or gaseous hydrogen for H2 storage has been developed for use in implantable neuroprosthetic devices. In this paper, pressure variations inside the cell for the gaseous hydrogen version are analyzed and correlated with oxygen evolution side reaction at the end of charging, the recombination of oxygen with hydrogen during charging and a subsequent rest period, and the self-discharge of the nickel electrode. About 70% of the recombination occurred simultaneously with oxygen evolution during charging and the remaining oxygen recombined with hydrogen during the 1st hour after charging. Self-discharge of the cell varies linearly with hydrogen pressure at a given state of charge and increased with increasing battery charge levels. The coulometric efficiency calculated based on analysis of the pressure-time data agreed well with the efficiency calculated based on the current-time data. Pressure variations in the battery are simulated accurately to predict coulometric efficiency and the state of charge of the cell, factors of extreme importance for a battery intended for implantation within the human body. PMID:22423175

  12. Subchannel analysis with turbulent mixing rate of supercritical pressure fluid

    International Nuclear Information System (INIS)

    Wu, Jianhui; Oka, Yoshiaki

    2015-01-01

    Highlights: • Subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out. • Turbulent mixing rate is enhanced, compared with that calculated by the law of pressurized water reactor (PWR). • Increase in maximum cladding surface temperature (MCST) is smaller comparing with PWR model. • The sensitivities of MCST on non-uniformity of subchannel area and power peaking are reduced by using SPF model. - Abstract: The subchannel analysis with turbulent mixing rate law of supercritical pressure fluid (SPF) is carried out for supercritical-pressurized light water cooled and moderated reactor (Super LWR). It is different from the turbulent mixing rate law of pressurized water reactor (PWR), which is widely adopted in Super LWR subchannel analysis study, the density difference between adjacent subchannels is taken into account for turbulent mixing rate law of SPF. MCSTs are evaluated on three kinds of fuel assemblies with different pin power distribution patterns, gap spacings and mass flow rates. Compared with that calculated by employing turbulent mixing rate law of PWR, the increase in MCST is smaller even when peaking factor is large and gap spacing is uneven. The sensitivities of MCST on non-uniformity of the subchannel area and power peaking are reduced

  13. Meta-analysis of timolol on diurnal and nighttime intraocular pressure and blood pressure.

    LENUS (Irish Health Repository)

    Lee, Princeton Wen-Yuan

    2012-02-01

    PURPOSE: To evaluate the nighttime intraocular pressure (IOP) and blood pressure (BP) response to timolol treatment in patients with ocular hypertension or primary open-angle glaucoma. METHODS: This was a meta-analysis of previously published studies that must have been randomized, prospective, crossover or parallel, single or double-masked trials. The treatment period must have been >\\/=2 weeks with >\\/=19 patients per treatment arm for a crossover, and >\\/=50 patients for a parallel designed trial. Studies must have included both baseline and treated 24-hour curves. RESULTS: For the IOP analysis, we included 8 articles with 340 patients. A reduction from baseline was observed for timolol at each time point and for the 24-hour curve (p<\\/=0.009). When 2 studies, in which timolol was used adjunctively, were removed, a similar difference was observed as above at each time point and for the 24-hour curve (p<\\/=0.003). In 2 studies, there were small reductions from baseline for the mean diastolic and systolic BPs at most time points and for the 24-hour curve (3.9 and 4.2 mmHg, respectively) with timolol treatment. The ocular perfusion pressure did not show any difference between baseline and timolol treatment at any time point or for the 24-hour curve (p>0.05). CONCLUSIONS: This meta-analysis suggests that topical timolol therapy provides an ocular hypotensive effect over the 24-hour curve, including the nighttime hours, and while small reductions in the systolic and diastolic pressures occur, the ocular perfusion pressure is not altered over 24 hours.

  14. Fast intraslab fluid-flow events linked to pulses of high pore fluid pressure at the subducted plate interface

    Science.gov (United States)

    Taetz, Stephan; John, Timm; Bröcker, Michael; Spandler, Carl; Stracke, Andreas

    2018-01-01

    A better understanding of the subduction zone fluid cycle and its chemical-mechanical feedback requires in-depth knowledge about how fluids flow within and out of descending slabs. Relicts of fluid-flow systems in exhumed rocks of fossil subduction zones allow for identification of the general relationships between dehydration reactions, fluid pathway formation, the dimensions and timescales of distinct fluid flow events; all of which are required for quantitative models for fluid-induced subduction zone processes. Two types of garnet-quartz-phengite veins can be distinguished in an eclogite-facies mélange block from the Pouébo Eclogite Mélange, New Caledonia. These veins record synmetamorphic internal fluid release by mineral breakdown reactions (type I veins), and infiltration of an external fluid (type II veins) with the associated formation of a reaction selvage. The dehydration and fluid migration documented by the type I veins likely occurred on a timescale of 105-106 years, based on average subduction rates and metamorphic conditions required for mineral dehydration and fluid flow. The timeframe of fluid-rock interaction between the external fluid and the wall-rock of the type II veins is quantified using a continuous bulk-rock Li-diffusion profile perpendicular to a vein and its metasomatic selvage. Differences in Li concentration between the internal and external fluid reservoirs resulted in a distinct diffusion profile (decreasing Li concentration and increasing δ7 Li) as the reaction front propagated into the host rock. Li-chronometric constraints indicate that the timescales of fluid-rock interaction associated with type II vein formation are on the order of 1 to 4 months (0.150-0.08+0.14 years). The short-lived, pulse-like character of this process is consistent with the notion that fluid flow caused by oceanic crust dehydration at the blueschist-to-eclogite transition contributes to or even dominates episodic pore fluid pressure increases at the

  15. Stress analysis and evaluation of a rectangular pressure vessel

    International Nuclear Information System (INIS)

    Rezvani, M.A.; Ziada, H.H.; Shurrab, M.S.

    1992-10-01

    This study addresses structural analysis and evaluation of an abnormal rectangular pressure vessel, designed to house equipment for drilling and collecting samples from Hanford radioactive waste storage tanks. It had to be qualified according to ASME boiler and pressure vessel code, Section VIII; however, it had the cover plate bolted along the long face, a configuration not addressed by the code. Finite element method was used to calculate stresses resulting from internal pressure; these stresses were then used to evaluate and qualify the vessel. Fatigue is not a concern; thus, it can be built according to Section VIII, Division I instead of Division 2. Stress analysis was checked against the code. A stayed plate was added to stiffen the long side of the vessel

  16. Leak detection in pipelines through spectral analysis of pressure signals

    Directory of Open Access Journals (Sweden)

    Souza A.L.

    2000-01-01

    Full Text Available The development and test of a technique for leak detection in pipelines is presented. The technique is based on the spectral analysis of pressure signals measured in pipeline sections where the formation of stationary waves is favoured, allowing leakage detection during the start/stop of pumps. Experimental tests were performed in a 1250 m long pipeline for various operational conditions of the pipeline (liquid flow rate and leakage configuration. Pressure transients were obtained by four transducers connected to a PC computer. The obtained results show that the spectral analysis of pressure transients, together with the knowledge of reflection points provide a simple and efficient way of identifying leaks during the start/stop of pumps in pipelines.

  17. Does chocolate reduce blood pressure? A meta-analysis.

    Science.gov (United States)

    Ried, Karin; Sullivan, Thomas; Fakler, Peter; Frank, Oliver R; Stocks, Nigel P

    2010-06-28

    Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals. We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P chocolate compared with control (mean BP change +/- SE: SBP: -3.2 +/- 1.9 mmHg, P = 0.001; DBP: -2.0 +/- 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 +/- 3.0 mmHg; P = 0.0009; DBP: -2.7 +/- 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 +/- 2.3 mmHg, P = 0.17; DBP: -1.3 +/- 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors

  18. A method of precise profile analysis of diffuse scattering for the KENS pulsed neutrons

    International Nuclear Information System (INIS)

    Todate, Y.; Fukumura, T.; Fukazawa, H.

    2001-01-01

    An outline of our profile analysis method, which is now of practical use for the asymmetric KENS pulsed thermal neutrons, are presented. The analysis of the diffuse scattering from a single crystal of D 2 O is shown as an example. The pulse shape function is based on the Ikeda-Carpenter function adjusted for the KENS neutron pulses. The convoluted intensity is calculated by a Monte-Carlo method and the precision of the calculation is controlled. Fitting parameters in the model cross section can be determined by the built-in nonlinear least square fitting procedure. Because this method is the natural extension of the procedure conventionally used for the triple-axis data, it is easy to apply with generality and versatility. Most importantly, furthermore, this method has capability of precise correction of the time shift of the observed peak position which is inevitably caused in the case of highly asymmetric pulses and broad scattering function. It will be pointed out that the accurate determination of true time-of-flight is important especially in the single crystal inelastic experiments. (author)

  19. Evaluation of arterial propagation velocity based on the automated analysis of the Pulse Wave Shape

    International Nuclear Information System (INIS)

    Clara, F M; Scandurra, A G; Meschino, G J; Passoni, L I

    2011-01-01

    This paper proposes the automatic estimation of the arterial propagation velocity from the pulse wave raw records measured in the region of the radial artery. A fully automatic process is proposed to select and analyze typical pulse cycles from the raw data. An adaptive neuro-fuzzy inference system, together with a heuristic search is used to find a functional approximation of the pulse wave. The estimation of the propagation velocity is carried out via the analysis of the functional approximation obtained with the fuzzy model. The analysis of the pulse wave records with the proposed methodology showed small differences compared with the method used so far, based on a strong interaction with the user. To evaluate the proposed methodology, we estimated the propagation velocity in a population of healthy men from a wide range of ages. It has been found in these studies that propagation velocity increases linearly with age and it presents a considerable dispersion of values in healthy individuals. We conclude that this process could be used to evaluate indirectly the propagation velocity of the aorta, which is related to physiological age in healthy individuals and with the expectation of life in cardiovascular patients.

  20. DynPeak: An Algorithm for Pulse Detection and Frequency Analysis in Hormonal Time Series

    Science.gov (United States)

    Vidal, Alexandre; Zhang, Qinghua; Médigue, Claire; Fabre, Stéphane; Clément, Frédérique

    2012-01-01

    The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm. PMID:22802933

  1. Time-Frequency (Wigner Analysis of Linear and Nonlinear Pulse Propagation in Optical Fibers

    Directory of Open Access Journals (Sweden)

    José Azaña

    2005-06-01

    Full Text Available Time-frequency analysis, and, in particular, Wigner analysis, is applied to the study of picosecond pulse propagation through optical fibers in both the linear and nonlinear regimes. The effects of first- and second-order group velocity dispersion (GVD and self-phase modulation (SPM are first analyzed separately. The phenomena resulting from the interplay between GVD and SPM in fibers (e.g., soliton formation or optical wave breaking are also investigated in detail. Wigner analysis is demonstrated to be an extremely powerful tool for investigating pulse propagation dynamics in nonlinear dispersive systems (e.g., optical fibers, providing a clearer and deeper insight into the physical phenomena that determine the behavior of these systems.

  2. Influence of oxygen pressure and aging on LaAlO3 films grown by pulsed laser deposition on SrTiO3 substrates

    KAUST Repository

    Park, Jihwey

    2014-02-24

    The crystal structures of LaAlO3 films grown by pulsed laser deposition on SrTiO3 substrates at oxygen pressure of 10−3 millibars or 10−5 millibars, where kinetics of ablated species hardly depend on oxygen background pressure, are compared. Our results show that the interface between LaAlO3 and SrTiO3 is sharper when the oxygen pressure is lower. Over time, the formation of various crystalline phases is observed while the crystalline thickness of the LaAlO3 layer remains unchanged. X-ray scattering as well as atomic force microscopy measurements indicate three-dimensional growth of such phases, which appear to be fed from an amorphous capping layer present in as-grown samples.

  3. Photoelastic stress analysis in mitred bend under internal pressure

    International Nuclear Information System (INIS)

    Sawa, Yoshiaki

    1987-01-01

    The stress analysis and stress relaxation in mitred bend subjected to internal pressure have been studied by means of the photoelastic stress freezing method. The experimental results show that stress concentration occurs in the wedge tip of the intersectional plane and it is considerably influenced by the bent angle. Then, the stress relaxation was obtained by planing the wedge tip. (author)

  4. Theoretical analysis of material removal mechanisms in pulsed laser fusion cutting of ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Quintero, F [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Varas, F [Dpto Matematica Aplicada II, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Pou, J [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Lusquinos, F [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Boutinguiza, M [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Soto, R [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain); Perez-Amor, M [Dpto FIsica Aplicada, Universidad de Vigo, ETS Ingenieros Industriales, Lagoas-Marcosende 9, 36310 Vigo (Spain)

    2005-02-21

    It is well known that the efficiency of material removal mechanisms has a crucial influence on the performance and quality of the laser cutting process. However, they are very difficult to study since the physical processes and parameters which govern them are quite complicated to observe and measure experimentally. For this reason, the development of theoretical models to analyse the material removal mechanisms is very important for understanding the characteristics and influence of these processes. In this paper, a theoretical model of the pulsed laser fusion cutting of ceramics is presented. The material removal mechanisms from the cutting front are modelled under the assumption that the ceramic material may be, simultaneously, melted and evaporated by the laser radiation. Therefore, three ejection mechanisms are investigated together: ejection of molten material by the assist gas, evaporation of the liquid and ejection of molten material due to the recoil pressure generated by the evaporation from the cutting front. The temporal evolution of the material removal mechanisms and the thickness of the molten layer are solved for several laser pulse modes. Theoretical results are compared with experimental observations to validate the conclusions regarding the influence of frequency and pulse length on the cutting process.

  5. Gas Hydrate-Sediment Morphologies Revealed by Pressure Core Analysis

    Science.gov (United States)

    Holland, M.; Schultheiss, P.; Roberts, J.; Druce, M.

    2006-12-01

    Analysis of HYACINTH pressure cores collected on IODP Expedition 311 and NGHP Expedition 1 showed gas hydrate layers, lenses, and veins contained in fine-grained sediments as well as gas hydrate contained in coarse-grained layers. Pressure cores were recovered from sediments on the Cascadia Margin off the North American West Coast and in the Krishna-Godavari Basin in the Western Bay of Bengal in water depths of 800- 1400 meters. Recovered cores were transferred to laboratory chambers without loss of pressure and nondestructive measurements were made at in situ pressures and controlled temperatures. Gamma density, P-wave velocity, and X-ray images showed evidence of grain-displacing and pore-filling gas hydrate in the cores. Data highlights include X-ray images of fine-grained sediment cores showing wispy subvertical veins of gas hydrate and P-wave velocity excursions corresponding to grain-displacing layers and pore-filling layers of gas hydrate. Most cores were subjected to controlled depressurization experiments, where expelled gas was collected, analyzed for composition, and used to calculate gas hydrate saturation within the core. Selected cores were stored under pressure for postcruise analysis and subsampling.

  6. Usability of a new multiple high-speed pulse time data registration, processing and real-time display system for pulse time interval analysis

    International Nuclear Information System (INIS)

    Yawata, Takashi; Sakaue, Hisanobu; Hashimoto, Tetsuo; Itou, Shigeki

    2006-01-01

    A new high-speed multiple pulse time data registration, processing and real-time display system for time interval analysis (TIA) was developed for counting either β-α or α-α correlated decay-events. The TIA method has been so far limited to selective extraction of successive α-α decay events within the milli-second time scale owing to the use of original electronic hardware. In the present pulse-processing system, three different high-speed α/β(γ) pulses could be fed quickly to original 32 bit PCI board (ZN-HTS2) within 1 μs. This original PCI board is consisting of a timing-control IC (HTS-A) and 28 bit counting IC (HTS-B). All channel and pulse time data were stored to FIFO RAM, followed to transfer into temporary CPU RAM (32 MB) by DMA. Both data registration (into main RAM (200 MB)) and calculation of pulse time intervals together with real-time TIA-distribution display simultaneously processed using two sophisticate softwares. The present system has proven to succeed for the real-time display of TIA distribution spectrum even when 1.6x10 5 cps pulses from pulse generator were given to the system. By using this new system combined with liquid scintillation counting (LSC) apparatus, both a natural micro-second order β-α correlated decay-events and a milli-second order α-α correlated decay-event could be selectively extracted from the mixture of natural radionuclides. (author)

  7. Pressure and pressure derivative analysis for injection tests with variable temperature without type-curve matching

    International Nuclear Information System (INIS)

    Escobar, Freddy Humberto; Martinez, Javier Andres; Montealegre Matilde

    2008-01-01

    The analysis of injection tests under nonisothermic conditions is important for the accurate estimation of the reservoir permeability and the well's skin factor; since previously an isothermical system was assumed without taking into account a moving temperature front which expands with time plus the consequent changes in both viscosity and mobility between the cold and the hot zone of the reservoir which leads to unreliable estimation of the reservoir and well parameters. To construct the solution an analytical approach presented by Boughrara and Peres (2007) was used. That solution was initially introduced for the calculation of the injection pressure in an isothermic system. It was later modified by Boughrara and Reynolds (2007) to consider a system with variable temperature in vertical wells. In this work, the pressure response was obtained by numerical solution of the anisothermical model using the Gauss Quadrature method to solve the integrals, and assuming that both injection and reservoir temperatures were kept constant during the injection process and the water saturation is uniform throughout the reservoir. For interpretation purposes, a technique based upon the unique features of the pressure and pressure derivative curves were used without employing type-curve matching (TDS technique). The formulation was verified by its application to field and synthetic examples. As expected, increasing reservoir temperature causes a decrement in the mobility ratio, then estimation of reservoir permeability is some less accurate from the second radial flow, especially, as the mobility ratio increases

  8. Slideline verification for multilayer pressure vessel and piping analysis

    International Nuclear Information System (INIS)

    Van Gulick, L.A.

    1983-01-01

    Nonlinear finite element method (FEM) computer codes with slideline algorithm implementations should be useful for the analysis of prestressed multilayer pressure vessels and piping. This paper presents closed form solutions useful for validating slideline implementations for this purpose. The solutions describe stresses and displacements of an internally pressurized elastic-plastic sphere initially separated from an elastic outer sphere by a uniform gap. Comparison of closed form and FEM results evaluates the usefulness of the closed form solution and the validity of the slideline implementation used

  9. Numerical investigation of the effect of driving voltage pulse shapes on the characteristics of low-pressure argon dielectric barrier discharge

    International Nuclear Information System (INIS)

    Eslami, E.; Barjasteh, A.; Morshedian, N.

    2015-01-01

    In this work, we numerically compare the effect of a sinusoidal, triangular, and rectangular pulsed voltage profile on the calculated particle production, electric current, and gas voltage in a dielectric barrier discharge. The total argon gas pressure of 400 Pa, the distance between dielectrics of 5 mm, the dielectric thickness of 0.7 mm, and the temperature of T = 300 K were considered as input parameters. The different driving voltage pulse shapes (triangular, rectangular, and sinusoidal) are considered as applied voltage with a frequency of 7 kHz and an amplitude of 700 V peak to peak. It is shown that applying a rectangular voltage, as compared with a sinusoidal or triangle voltage, increases the current peak, while the peak width is decreased. Higher current density is related to high production of charged particles, which leads to the generation of some highly active species, such as Ar* (4s level), and Ar** (4p level) in the gap

  10. Analysis of cracked pressure vessel nozzles by finite elements

    International Nuclear Information System (INIS)

    Reynen, J.

    1975-01-01

    In order to assess the safety of pressure vessel nozzles, the analysis should take into account cracks. The paper describes various algorithms, their computer implementations and relative merits to define in an effective way strain energy release rates along the tip front of arbitrary 3 D cracks under arbitary load including thermal strains. These techniques are basically equivalent to substructuring techniques and consequently they can be implemented to only FEM program able to deal with the data handling problems of the substructuring technique. Examples are given carried out with a substructure version of the BERSAFE system. These examples include a corner crack in a pressure vessel nozzle loaded by internal pressure and by thermal stresses. (Auth.)

  11. Vent clearing analysis of a Mark III pressure suppression containment

    International Nuclear Information System (INIS)

    Quintana, R.

    1979-01-01

    An analysis of the vent clearing transient in a Mark III pressure suppression containment after a hypothetical LOCA is carried out. A two-dimensional numerical model solving the transient fluid dynamic equations is used. The geometry of the pressure suppression pool is represented and the pressure and velocity fields in the pool are obtained from the moment the LOCA occurs until the first vent in the drywell wall clears. The results are compared to those obtained with the one-diemensional model used for containment design, with special interest on two-dimensional effects. Some conclusions concerning the effect of the water discharged into the suppression pool through the vents on submerged structures are obtained. Future improvements to the model are suggested. (orig.)

  12. Processing and Probability Analysis of Pulsed Terahertz NDE of Corrosion under Shuttle Tile Data

    Science.gov (United States)

    Anastasi, Robert F.; Madaras, Eric I.; Seebo, Jeffrey P.; Ely, Thomas M.

    2009-01-01

    This paper examines data processing and probability analysis of pulsed terahertz NDE scans of corrosion defects under a Shuttle tile. Pulsed terahertz data collected from an aluminum plate with fabricated corrosion defects and covered with a Shuttle tile is presented. The corrosion defects imaged were fabricated by electrochemically etching areas of various diameter and depth in the plate. In this work, the aluminum plate echo signal is located in the terahertz time-of-flight data and a threshold is applied to produce a binary image of sample features. Feature location and area are examined and identified as corrosion through comparison with the known defect layout. The results are tabulated with hit, miss, or false call information for a probability of detection analysis that is used to identify an optimal processing threshold.

  13. Structure analysis of liquids and disordered materials using pulsed neutron diffraction and total scattering

    International Nuclear Information System (INIS)

    Suzuya, Kentaro

    2011-01-01

    Neutron diffraction·total scattering at pulsed neutron source is a powerful method to analyze the complex structure of disordered materials: liquids, glasses, amorphous materials and disordered crystals. The basic idea of the structure of disordered materials, the fundamental diffraction theory for disordered materials, and structure analysis of disordered materials using pulsed neutron diffraction·total scattering technique (TOF method) are described in detail. In addition, the precise information of the world highest class J-PARC MLF spallation neutron source and typical J-PARC neutron total scattering instrument NOVA are also given. Recent structural modelling methods of disordered materials such like reverse Monte Carlo (RMC) simulation method is briefly described using an example of the analysis of a typical disordered material silica glass. (author)

  14. Stability analysis of supercritical-pressure light water-cooled reactor in constant pressure operation

    International Nuclear Information System (INIS)

    Suhwan, JI; Shirahama, H.; Koshizuka, S.; Oka, Y.

    2001-01-01

    The purpose of this study is to evaluate the thermal-hydraulic and the thermal-nuclear coupled stabilities of a supercritical pressure light water-cooled reactor. A stability analysis code at supercritical pressure is developed. Using this code, stabilities of full and partial-power reactor operating at supercritical pressure are investigated by the frequency-domain analysis. Two types of SCRs are analyzed; a supercritical light water reactor (SCLWR) and a supercritical water-cooled fast reactor (SCFR). The same stability criteria as Boiling Water Reactor are applied. The thermal-hydraulic stability of SCLWR and SCFR satisfies the criteria with a reasonable orifice loss coefficient. The decay ratio of the thermal-nuclear coupled stability in SCFR is almost zero because of a small coolant density coefficient of the fast reactor. The evaluated decay ratio of the thermal-nuclear coupled stability is 3,41 ∼ 10 -V at 100% power in SCFR and 0,028 at 100% power in SCLWR. The sensitivity is investigated. It is found that the thermal-hydraulic stability is sensitive to the mass flow rate strongly and the thermal-nuclear coupled stability to the coolant density coefficient. The bottom power peak distribution makes the thermal-nuclear stability worse and the thermal-nuclear stability better. (author)

  15. Decoupling Analysis on Pressure Fluctuation and Needle Valve Response for High Pressure Common Rail Injector

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2017-01-01

    Full Text Available In the process of multiple injections, the influence of different injections makes the controlling of cycle fuel injection quantity more difficult. The high pressure common rail (HPCR simulation model is established in AMESim environment. Through the method of combining numerical simulation and experiment test, it is found that the strong coupling of pressure fluctuation and needle valve response is the fundamental reason, which leads to the fluctuation of main injection fuel quantity (MIFQ with dwell time (DT. The result shows that the largest fluctuation quantity is 3.6mm3 when the reference value of main injection is 60.0mm3. Non-damping LC hydraulic system model is also established. Through the analysis of the model, reducing the length-diameter ratio of internal oil duct and the delivery chamber volume are decoupling methods to the strong coupling.

  16. An Analysis to Strategy of Pulse Research in Iran Based Upon the First National Pulse Symposium Approaches

    Directory of Open Access Journals (Sweden)

    abdolreza bagheri

    2009-06-01

    Full Text Available Pulse, as the second source of human nutrition, benefits from great agronomic and nutritious features. These plants are amongst the most important crops which are full of protein and are widely cultivated all over the world; having the ability to adapt to different climate measures ranging from mild to hot and from moist to very dry. The other noteworthy trait of these crops is their talent to coexist with nitrogen fixation bacteria available in the soil which plays an important role in soil fertility and sustainability. For the previously mentioned reasons and many more, pulses have been extensive fields of research. With the substitution of legumes with fallow in the wheat-fallow agricultural system, great success in product stability has been gained. Having emphasized on the importance of the issue, the first national pulse symposium with the aim of investigating the opportunities and threats facing the development of pulse in Iran was held on 20-21 Nov. 2005 in the Ferdowsi University of Mashhad at the Research Center of Plant Sciences in collaboration with many scientific, research and administrative institutions. This paper aims at sketching the overview of the strategic research direction in Iran by analyzing the published papers presented in this conference and will provide the key points mentioned in the final conference manifestation.

  17. Temporal evolution of electron density in a low pressure pulsed two-frequency (60 MHz/2 MHz) capacitively coupled plasma discharge

    International Nuclear Information System (INIS)

    Sirse, N; Ellingboe, A R; Jeon, M H; Yeom, G Y

    2014-01-01

    Time-resolved electron density, n e , is measured in a low pressure pulsed two-frequency capacitively coupled plasma discharge sustained in Ar and in Ar/CF 4 /O 2 (80 : 10 : 10) gas mixture using a floating resonance hairpin probe. The top electrode is powered by 60 MHz in pulse mode and the bottom electrode is powered by 2 MHz in continuous wave mode. The dependence of time-resolved n e on the low frequency (LF) and high frequency (HF) power levels, operating gas pressure, pulse repetition frequency (PRF) and duty cycle are investigated. It is found that the steady state n e in the long on-phase is greatly influenced by the HF power level and slightly affected by the LF power level in both Ar and Ar/CF 4 /O 2 plasma. The decay time of n e is slow (∼30–90 µs) in the case of Ar plasma and strongly depends on the LF power level, whereas in the case of Ar/CF 4 /O 2 gas mixture it is very fast (∼15 µs) and marginally dependent on LF power level. In Ar plasma the steady state n e is increasing with a rise in operating gas pressure, however, in Ar/CF 4 /O 2 plasma it first increases with gas pressure reaching to the maximum (at 20 mTorr) value and then decreases. The pressure dependence of decay time constant mimics the pressure variation of steady state n e . Furthermore, it is observed that the on-phase electron density is greatly affected by changing the PRF and duty cycle. This effect is more prominent in Ar/CF 4 /O 2 plasma when compared to Ar discharge. In addition, n e is observed to overshoot the steady state densities in the beginning of the on-phase in Ar/CF 4 /O 2 gas mixture, but this effect is either small or absent in the case of Ar plasma. (paper)

  18. [Parkinson gait analysis using in-shoe plantar pressure measurements].

    Science.gov (United States)

    Pihet, D; Moretto, P; Defebvre, L; Thevenon, A

    2006-02-01

    The literature reports some studies describing the walking pattern of patients with Parkinson's disease, its deterioration with disease severity and the effects of various treatments. Other studies concerned the plantar pressure distribution when walking. The aim of this study was to validate the use of baropodometric measurements for gait analysis of parkinsonian patients at various stages of disease severity and in on and off phases. Fifteen normal control subjects and fifteen parkinsonian patients equipped with a plantar pressure measurement system performed walking tests. The parkinsonian patients performed the walking tests in off phase then in on phase. A clinical examination was performed to score the motor handicap on the UPDRS scale. Analysis of the plantar pressures of the parkinsonian subjects under various footprint areas detected significant baropodometric differences compared with controls, between groups with different UPDRS scores, and before and after L-Dopa treatment. Plantar pressures measurements allow a sufficiently fine discrimination for using it to detect parkinsonism and monitor patients with Parkinson's disease.

  19. A statistical method for draft tube pressure pulsation analysis

    International Nuclear Information System (INIS)

    Doerfler, P K; Ruchonnet, N

    2012-01-01

    Draft tube pressure pulsation (DTPP) in Francis turbines is composed of various components originating from different physical phenomena. These components may be separated because they differ by their spatial relationships and by their propagation mechanism. The first step for such an analysis was to distinguish between so-called synchronous and asynchronous pulsations; only approximately periodic phenomena could be described in this manner. However, less regular pulsations are always present, and these become important when turbines have to operate in the far off-design range, in particular at very low load. The statistical method described here permits to separate the stochastic (random) component from the two traditional 'regular' components. It works in connection with the standard technique of model testing with several pressure signals measured in draft tube cone. The difference between the individual signals and the averaged pressure signal, together with the coherence between the individual pressure signals is used for analysis. An example reveals that a generalized, non-periodic version of the asynchronous pulsation is important at low load.

  20. Transition to Pulse-Like Rupture, With and Without Inclusion of Evolving Temperature and Pore Pressure, When Accounting for Extreme Weakening at High Slip Rates

    Science.gov (United States)

    Noda, H.; Dunham, E. M.; Rice, J. R.

    2007-12-01

    We have conducted rupture propagation simulations incorporating the combined effects of thermal pressurization of pore fluid by distributed heating within a finite width shear zone, and flash heating of microscopic contacts. These are probably the primary weakening mechanisms at high coseismic slip rates. For flash heating, we use a rate- and state-dependent friction law in the slip law formulation, accounting for extreme velocity weakening above a weakening slip rate Vw ~ 0.1 m/s that depends on the background temperature, and a very short state evolution distance, L, of ~ 10 μm, which is comparable to the asperity length. We have also conducted a series of calculations with neglecting evolving change in macroscopic temperature, T, and pore pressure, p, and compared the results. Slip rate, V, at a point on a fault increases when a rupture front approaches, and decreases behind it. In the pulse-like solutions, V decreases below Vw, and the point is eventually locked. On the other hand, in the crack-like solutions, V increases again only if we allow evolving change in T and p. In the cases when we neglect changes in T and p, V continues to decrease behind the rupture front as long as we simulate. Here, a question emerges; is the solution crack-like because of the short calculation time? Zheng and Rice [1998] proposed an intuitive criterion between crack-like and pulse-like solutions as follows: If and only if the background shear stress, τb, is larger than a critical value, τpulse, there are roots of τss(V) = τb - μ V/2 cs, where τss is steady-state strength, μ is shear modulus and cs is shear speed. If TZR = - (μ/2cs)/(dτss/dV) at the largest root is near unity, the solution is pulse-like. Our calculations without T and p changes show that the pulse-like solution regime extends above τpulse, at least up to the point where TZR = 0.176, if a rupture is initiated by a perturbation in shear stress in a certain manner. The transition time to pulse

  1. The effect of O2 partial pressure on the photoluminescence of ZnO thin films grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Lu, Y.M.; Li, X.P.; Su, S.C.; Cao, P.J.; Jia, F.; Han, S.; Zeng, Y.X.; Liu, W.J.; Zhu, D.L.

    2014-01-01

    In this paper, photoluminescence (PL) of ZnO thin films prepared on c-Al 2 O 3 substrates by the pulsed laser deposition (PLD) method at different O 2 partial pressures is investigated. For all samples, a narrow ultraviolet (UV) emission and a broad visible emission can be observed at room-temperature (RT). With increasing O 2 partial pressures from 0.2 to 5 Pa, the intensity ratio of the UV to visible emissions increases, and the energy positions of the UV emission band shift to the high energy side. It is noted that the visible part includes two emission bands of green luminescence (GL) and yellow luminescence (YL), in which the GL emission is strong at low oxygen pressure and the YL emission becomes dominant at high O 2 partial pressures. The temperature-dependent PL spectra show that the UV emission is composed of two bands labeled FX and FA. The dependences and possible assignments of these PL bands are briefly discussed. - Highlights: • We confirmed that the RT UV emission band is due to two transitions of the FX and FA. • The intensity of the FX and FA emission bands strongly depends on oxygen partial pressures. • We deduced that the acceptor-like defects located in the grain boundaries are responsible for the FA emission. • The visible emission includes the GL related to V O and the YL related to V Zn or O i . • The GL emission strongly affects the UV emission

  2. Development of soft ionization using direct current pulse glow discharge plasma source in mass spectrometry for volatile organic compounds analysis

    Science.gov (United States)

    Nunome, Yoko; Kodama, Kenji; Ueki, Yasuaki; Yoshiie, Ryo; Naruse, Ichiro; Wagatsuma, Kazuaki

    2018-01-01

    This study describes an ionization source for mass analysis, consisting of glow discharge plasma driven by a pulsed direct-current voltage for soft plasma ionization, to detect toxic volatile organic compounds (VOCs) rapidly and easily. The novelty of this work is that a molecular adduct ion, in which the parent molecule attaches with an NO+ radical, [M + NO]+, can be dominantly detected as a base peak with little or no fragmentation of them in an ambient air plasma at a pressure of several kPa. Use of ambient air as the discharge plasma gas is suitable for practical applications. The higher pressure in an ambient air discharge provided a stable glow discharge plasma, contributing to the soft ionization of organic molecules. Typical mass spectra of VOCs toluene, benzene, o-xylene, chlorobenzene and n-hexane were observed as [M + NO]+ adduct ion whose peaks were detected at m/z 122, 108, 136, 142 and 116, respectively. The NO generation was also confirmed by emission bands of NO γ-system. The ionization reactions were suggested, such that NO+ radical formed in an ambient air discharge could attach with the analyte molecule.

  3. Central Arterial Function Measured by Non-invasive Pulse Wave Analysis is Abnormal in Patients with Duchenne Muscular Dystrophy.

    Science.gov (United States)

    Ryan, Thomas D; Parent, John J; Gao, Zhiqian; Khoury, Philip R; Dupont, Elizabeth; Smith, Jennifer N; Wong, Brenda; Urbina, Elaine M; Jefferies, John L

    2017-08-01

    Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutation of dystrophin. Cardiovascular involvement includes dilated cardiomyopathy. Non-invasive assessment of vascular function has not been evaluated in DMD. We hypothesize arterial wave reflection is abnormal in patients with DMD. Pulse wave analysis was performed on DMD patients with a SphygmoCor SCOR-PVx System to determine central blood pressure and augmentation index (AIx) as an assessment of arterial wave reflection. Results were compared to a control group. A total of 43 patients with DMD were enrolled, and compared to 43 normal controls. Central systolic blood pressure was lower, while both AIx-75 (7.8 ± 9.6% vs. 2.1 ± 10.4%, p 0.01, DMD vs. normal) and AIx-not corrected (16.8 ± 10.1% vs. -3.6 ± 10.9, p wave reflection when compared to normal controls, which may represent increased arterial stiffness. Overall there appears to be no effect on ventricular systolic function, however the long-term consequence in this group is unknown. Further study is required to determine the mechanism of these differences, which may be related to the effects of systemic steroids or the role of dystrophin in vascular function.

  4. Neutron fluctuation analysis in a subcritical multiplying system with a stochastically pulsed poisson source

    International Nuclear Information System (INIS)

    Kostic, Lj.

    2003-01-01

    The influence of the stochastically pulsed Poisson source to the statistical properties of the subcritical multiplying system is analyzed in the paper. It is shown a strong dependence on the pulse period and pulse width of the source (author)

  5. Program for the analysis of pulse height spectra and the background from a proportional detector

    International Nuclear Information System (INIS)

    Flores-Llamas, H.; Yee-Madeira, H.; Contreras-Puente, G.; Zamorano-Ulloa, R.

    1991-01-01

    A PC-Fortran program is presented for fitting of lineshapes and the analysis of pulse height spectra obtainable with proportional detectors. The common fitting and analysis of pulse height spectra by means of mixed Gaussian lineshapes is readily improved by using Voigt lineshapes. In addition, the background can be evaluated during the fitting process without the need of extra measurements. As an application of the program, a pulse height transmission spectrum accumulated with a static 57 Co source and detected with an argon-metane proportional detector, was least squares fitted to an elaborated complex trial lineshape function containing two Voigt lines plus a straight line. The fitting straight line parameters a and b characterize quantitatively the background. The very good PC-fitting obtained shows that the fitting of experimental spectra with the more realistic Voigt lineshapes is no longer a formidable task and that it is possible to evaluate and subtract the background inherent to the experiment during the fitting process. (orig.)

  6. Analysis and prediction of radioelement dispersion in the marine environment by the pulse response method

    International Nuclear Information System (INIS)

    Boust, D.; Fraizier, A.; Hairie, A.; Baron, Y.

    1995-01-01

    This work presents analysis and prediction of the dispersion of radioelements in the marine environment based on the pulse response theory. The analysis is made on three data sets over the period 1984-1988: the amounts of gamma-emitting radioelements contained in controlled releases from the nuclear reprocessing plant of La Hague (=signal emission point), and gamma-emitting radionuclide concentrations in sea water at two stations (signal reception points), situated at 8 and 35 km distance from the release point. Using this data base, the pulse response is determined for each station and for each element. This allows us to estimate the mean delay and the amplitude of the reception signal (i.e. the concentrations of radioelements) and its sensitivity to wind forcing. We then demonstrate that the convolution of the pulse response and released radionuclide time-series is capable of yielding a fairly good prediction of the concentrations at each station. Some particularities of the behaviour of 137 Cs, 106 Ru and 60 Co are evidenced by comparison with that of 125 Sb, assumed to be a conservative element in sea water: adsorption of 106 Ru and 60 Co on to particles, additional sources of 137 Cs. The mean delays calculated for 125 Sb at each station are close to each other (28-30 days) despite their different distances from the release point, and are explained by the specific hydrodynamics of the studied area. (Authors). 16 refs., 9 figs

  7. Studies of Effect Analysis of Electromagnetic Pulses (EMP) in Operating Nuclear Power Plants (NPP)

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Song Hae; Ryu, Ho Sun; Kim, Min Yi; Lee, Eui Jong [KHNP, Daejeon (Korea, Republic of)

    2016-05-15

    The effect analysis of electromagnetic pulses (EMPs) has been studied for the past year by the Central Research Institute of Korea Hydro Nuclear Power Co. (KHNP) in order to better establish safety measures in operating nuclear power plants. What is an electromagnetic pulse (EMP)? As a general term for high-power electromagnetic radiation, it refers to strong electromagnetic pulses that destroy only electronic equipment devices in a short period without loss of life. The effect analysis of EMPs in operating NPPs and their corresponding safety measures in terms of selecting target devices against EMP impact have been examined in this paper. In general, domestic nuclear power plants do apply the design of fail-safe concepts. For example, if key instruments of a system fail because of EMPs, the control rods of a nuclear reactor are dropped automatically in order to maintain safe conditions of the NPP. Reactor cooling presents no problem because the diesel generator will adopt the analog starting circuit least affected by the electromagnetic waves.

  8. Perspectives for online analysis of raw material by pulsed neutron irradiation

    Science.gov (United States)

    Bach, Pierre; Le Tourneur, P.; Poumarede, B.

    1997-02-01

    On-line analysis by pulsed neutron irradiation is an example of an advanced technology application of nuclear techniques, concerning real problems in the cement, mineral and coal industries. The most significant of these nuclear techniques is their capability of continuous measurement without contact and without sampling, which can lead to improved control of processes and resultant large financial savings. Compared to Californium neutron sources, the use of electrical pulsed neutron generators allows to obtain a higher signal/noise ratio for a more sensitive measurement, and allows to overcome a number of safety problems concerning transportation, installation and maintenance. An experiment related to a possible new on-line raw material analyzer is described, using a pulsed neutron generator. The key factors contributing to an accurate measurement are related to a suitable generator, to a high count rate gamma ray spectroscopy electronics, and to computational tools. Calculation and results for the optimization of the neutron irradiation time diagram are reported. One of the operational characteristics of such an equipment is related to neutron flux available: it is possible to adjust it to the requested accuracy, i.e. for a high accuracy during a few hours/day and for a lower accuracy the rest of the time. This feature allows to operate the neutron tube during a longer time, and then to reduce the cost of analysis.

  9. MgxZn1-xO(0≤x<0.2) nanowire arrays on sapphire grown by high-pressure pulsed-laser deposition

    International Nuclear Information System (INIS)

    Lorenz, M.; Kaidashev, E.M.; Rahm, A.; Nobis, Th.; Lenzner, J.; Wagner, G.; Spemann, D.; Hochmuth, H.; Grundmann, M.

    2005-01-01

    Mg x Zn 1-x O nanowires with Mg-content x from 0 to 0.2 have been grown by high-pressure pulsed-laser deposition (PLD) on gold-covered sapphire single crystals. The PLD process allows for a unique wide-range control of morphology, diameter, and composition of the Mg x Zn 1-x O nanowires. The diameter of single ZnO wires could be varied between about 50 and 3000 nm, and the Mg content x of Mg x Zn 1-x O wire arrays was controlled via the PLD gas pressure. The microscopic homogeneity of Mg content is displayed by cathodoluminescence (CL) imaging of the excitonic peak energy. The fluctuation of CL peak energy between individual wires is about an order of magnitude smaller than the alloy broadening

  10. Effects of pressure and temperature on sintering of Cr-doped Al2O3 by pulsed electric current sintering process

    Science.gov (United States)

    Dang, K. Q.; Nanko, M.

    2011-03-01

    The aluminium oxide crystal, Al2O3, which contains a small amount of chromium, Cr, is called ruby. Pulsed electric current sintering (PECS) was applied to sinter ruby polycrystals. Cr2O3-Al2O3 powder mixture prepared by drying an aqueous slurry containing amounts of Al2O3 and Cr(NO3)3 was consolidated by PECS process. The PECS process was performed in vacuum at sintering temperature raging from 1100 to 1300°C with heating rate of 2 K/min under applied uniaxial pressure varied from 40 to 100 MPa. This study found that highly densified and transparent Cr-doped Al2O3 can be obtained by the PECS process with the high applied pressure at sintering temperature of 1200°C.

  11. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    International Nuclear Information System (INIS)

    Prabhu Gaunkar, N.; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C.; Bulu, I.; Ganesan, K.; Song, Y. Q.

    2015-01-01

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors

  12. Pulse shape analysis and position determination in segmented HPGe detectors: The AGATA detector library

    Energy Technology Data Exchange (ETDEWEB)

    Bruyneel, B. [Universitae