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Sample records for wind pressure pulses

  1. 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.

  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. 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.

  4. 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

  5. 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.

  6. 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

  7. 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...

  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. Full scale measurement of wind induced pressures : 1 configuration of wind induced pressures

    NARCIS (Netherlands)

    Geurts, C.P.W.; Wijen, H.L.M.

    1994-01-01

    A research project 10 the spectral characteristics of wind induced pressures is in progress in Eindhoven. This project includes both wind tunnel and full scale measurements. Wind induced pressures are measured in full scale at the main building of Eindhoven University of Technology. This paper

  10. Frequency Stepped Pulse Train Modulated Wind Sensing Lidar

    DEFF Research Database (Denmark)

    Olesen, Anders Sig; Pedersen, Anders Tegtmeier; Rottwitt, Karsten

    2011-01-01

    of frequency shifts corresponding to a specific distance. The spatial resolution depends on the repetition rate of the pulses in the pulse train. Directional wind measurements are shown and compared to a CW lidar measurement. The carrier to noise ratio of the FSPT lidar compared to a CW lidar is discussed......In this paper a wind sensing lidar utilizing a Frequency Stepped Pulse Train (FSPT) is demonstrated. One of the advantages in the FSTP lidar is that it enables direct measurement of wind speed as a function of distance from the lidar. Theoretically the FSPT lidar continuously produces measurements...... as is the case with a CW lidar, but at the same time with a spatial resolution, and without the range ambiguity originating from e.g. clouds. The FSPT lidar utilizes a frequency sweeping source for generation of the FSPT. The source generates a pulse train where each pulse has an optical carrier frequency...

  11. Pressure support for limiting strain in a superconducting winding

    International Nuclear Information System (INIS)

    Marston, P.G.; Nolan, J.J.

    1978-01-01

    A pressure support unit is described for limiting strain in a superconducting winding including a restraining member surrounding the superconducting winding; and a pressure compartment, having at least one segment for receiving pressurized fluid, disposed between the superconducting winding and the restraining member; and a pressure support system comprising a plurality of such pressure support units

  12. 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.

  13. Wind Tunnel Tests for Wind Pressure Distribution on Gable Roof Buildings

    Science.gov (United States)

    2013-01-01

    Gable roof buildings are widely used in industrial buildings. Based on wind tunnel tests with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Some characteristics of the measured wind pressure field on the surfaces of the models were analyzed, including mean wind pressure, fluctuating wind pressure, peak negative wind pressure, and characteristics of proper orthogonal decomposition results of the measured wind pressure field. The results show that extremely high local suctions often occur in the leading edges of longitudinal wall and windward roof, roof corner, and roof ridge which are the severe damaged locations under strong wind. The aspect ratio of building has a certain effect on the mean wind pressure coefficients, and the effect relates to wind attack angle. Compared with experimental results, the region division of roof corner and roof ridge from AIJ2004 is more reasonable than those from CECS102:2002 and MBMA2006.The contributions of the first several eigenvectors to the overall wind pressure distributions become much bigger. The investigation can offer some basic understanding for estimating wind load distribution on gable roof buildings and facilitate wind-resistant design of cladding components and their connections considering wind load path. PMID:24082851

  14. Low-level wind response to mesoscale pressure systems

    Science.gov (United States)

    Garratt, J. R.; Physick, W. L.

    1983-09-01

    Observations are presented which show a strong correlation between low-level wind behaviour (e.g., rotation near the surface) and the passage of mesoscale pressure systems. The latter are associated with frontal transition zones, are dominated by a pressure-jump line and a mesoscale high pressure area, and produce locally large horizontal pressure gradients. The wind observations are simulated by specifying a time sequence of perturbation pressure gradient and subsequently solving the vertically-integrated momentum equations with appropriate initial conditions. Very good agreement is found between observed and calculated winds; in particular, (i) a 360 ° rotation in wind on passage of the mesoscale high; (ii) wind-shift lines produced dynamically by the pressure-jump line; (iii) rapid linear increase in wind speed on passage of the pressure jump.

  15. 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 ...

  16. 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...

  17. Vortex, ULF wave and Aurora Observation after Solar Wind Dynamic Pressure Change

    Science.gov (United States)

    Shi, Q.

    2017-12-01

    Here we will summarize our recent study and show some new results on the Magnetosphere and Ionosphere Response to Dynamic Pressure Change/disturbances in the Solar Wind and foreshock regions. We study the step function type solar wind dynamic pressure change (increase/decrease) interaction with the magnetosphere using THEMIS satellites at both dayside and nightside in different geocentric distances. Vortices generated by the dynamic pressure change passing along the magnetopause are found and compared with model predictions. ULF waves and vortices are excited in the dayside and nightside plasma sheet when dynamic pressure change hit the magnetotail. The related ionospheric responses, such as aurora and TCVs, are also investigated. We compare Global MHD simulations with the observations. We will also show some new results that dayside magnetospheric FLRs might be caused by foreshock structures.Shi, Q. Q. et al. (2013), THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events, J. Geophys. Res. Space Physics, 118, doi:10.1029/2012JA017984. Shi, Q. Q. et al. (2014), Solar wind pressure pulse-driven magnetospheric vortices and their global consequences, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019551. Tian, A.M. et al.(2016), Dayside magnetospheric and ionospheric responses to solar wind pressure increase: Multispacecraft and ground observations, J. Geophys. Res., 121, doi:10.1002/2016JA022459. Shen, X.C. et al.(2015), Magnetospheric ULF waves with increasing amplitude related to solar wind dynamic pressure changes: THEMIS observations, J. Geophys. Res., 120, doi:10.1002/2014JA020913Zhao, H. Y. et al. (2016), Magnetospheric vortices and their global effect after a solar wind dynamic pressure decrease, J. Geophys. Res. Space Physics, 121, doi:10.1002/2015JA021646. Shen, X. C., et al. (2017), Dayside magnetospheric ULF wave frequency modulated by a solar wind dynamic pressure negative impulse, J. Geophys. Res

  18. Pressure field in measurement section of wind tunnel

    Directory of Open Access Journals (Sweden)

    Hnidka Jakub

    2017-01-01

    Full Text Available The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted.

  19. Influence of Wind Pressure on the Carbonation of Concrete.

    Science.gov (United States)

    Zou, Dujian; Liu, Tiejun; Du, Chengcheng; Teng, Jun

    2015-07-24

    Carbonation is one of the major deteriorations that accelerate steel corrosion in reinforced concrete structures. Many mathematical/numerical models of the carbonation process, primarily diffusion-reaction models, have been established to predict the carbonation depth. However, the mass transfer of carbon dioxide in porous concrete includes molecular diffusion and convection mass transfer. In particular, the convection mass transfer induced by pressure difference is called penetration mass transfer. This paper presents the influence of penetration mass transfer on the carbonation. A penetration-reaction carbonation model was constructed and validated by accelerated test results under high pressure. Then the characteristics of wind pressure on the carbonation were investigated through finite element analysis considering steady and fluctuating wind flows. The results indicate that the wind pressure on the surface of concrete buildings results in deeper carbonation depth than that just considering the diffusion of carbon dioxide. In addition, the influence of wind pressure on carbonation tends to increase significantly with carbonation depth.

  20. 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

  1. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    user

    and the over production of turbulent kinetic energy near the sharp edges. The various RANS ... can predict the general wind conditions around building reasonably well except those in the separation regions .... cable to a remote A/D converter.

  2. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... from full-scale observation, wind-tunnel experiments and various CFD techniques ... The paper is the result of extensive research concentrated on analyzing the accuracy and ...

  3. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    user

    turbulence models available widely and the state of the art techniques for the ... model, suitable for wind engineering applications, should be able to model the .... the Commonwealth Advisory Aeronautical Council (CAARC) building using vari-.

  4. 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 =

  5. 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)

  6. Wind tunnel and CFD modelling of wind pressures on solar energy systems on flat roofs

    NARCIS (Netherlands)

    Bronkhorst, A.J.; Franke, J.; Geurts, C.P.W.; Bentum, van C.A.; Grepinet, F.

    2010-01-01

    Design of solar energy mounting systems requires more knowledge on the wind patterns around these systems. To obtain more insight in the flow patterns, which cause the pressure distributions on the solar energy systems, a wind tunnel test and Computational Fluid Dynamics analysis have been

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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}.

  12. 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.)

  13. 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.).

  14. Physical understanding of the tropical cyclone wind-pressure relationship.

    Science.gov (United States)

    Chavas, Daniel R; Reed, Kevin A; Knaff, John A

    2017-11-08

    The relationship between the two common measures of tropical cyclone intensity, the central pressure deficit and the peak near-surface wind speed, is a long-standing problem in tropical meteorology that has been approximated empirically yet lacks physical understanding. Here we provide theoretical grounding for this relationship. We first demonstrate that the central pressure deficit is highly predictable from the low-level wind field via gradient wind balance. We then show that this relationship reduces to a dependence on two velocity scales: the maximum azimuthal-mean azimuthal wind speed and half the product of the Coriolis parameter and outer storm size. This simple theory is found to hold across a hierarchy of models spanning reduced-complexity and Earth-like global simulations and observations. Thus, the central pressure deficit is an intensity measure that combines maximum wind speed, storm size, and background rotation rate. This work has significant implications for both fundamental understanding and risk analysis, including why the central pressure better explains historical economic damages than does maximum wind speed.

  15. 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.

  16. 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

  17. Vandenberg Air Force Base Pressure Gradient Wind Study

    Science.gov (United States)

    Shafer, Jaclyn A.

    2013-01-01

    Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes pressure gradient thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.

  18. Wind turbine sound pressure level calculations at dwellings.

    Science.gov (United States)

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Leroux, Tony; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

  19. 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).

  20. Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment

    Directory of Open Access Journals (Sweden)

    N. J. T. Edberg

    2009-12-01

    Full Text Available We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during ~24 h in the combined data set from both spacecraft after Rosetta's closest approach to Mars on 25 February 2007. The bow shock and magnetic pileup boundary are coincidently observed by MEX to become asymmetric in their shapes. The fortunate orbit of MEX at this time allows a study of the inbound boundary crossings on one side of the planet and the outbound crossings on almost the opposite side, both very close to the terminator plane. The solar wind and interplanetary magnetic field (IMF downstream of Mars are monitored through simultaneous measurements provided by Rosetta. Possible explanations for the asymmetries are discussed, such as crustal magnetic fields and IMF direction. In the same interval, during the high solar wind pressure pulse, MEX observations show an increased amount of escaping planetary ions from the polar region of Mars. We link the high pressure solar wind with the observed simultaneous ion outflow and discuss how the pressure pulse could also be associated with the observed boundary shape asymmetry.

  1. 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

  2. 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.

  3. Influence of Wind Pressure on the Carbonation of Concrete

    Directory of Open Access Journals (Sweden)

    Dujian Zou

    2015-07-01

    Full Text Available Carbonation is one of the major deteriorations that accelerate steel corrosion in reinforced concrete structures. Many mathematical/numerical models of the carbonation process, primarily diffusion-reaction models, have been established to predict the carbonation depth. However, the mass transfer of carbon dioxide in porous concrete includes molecular diffusion and convection mass transfer. In particular, the convection mass transfer induced by pressure difference is called penetration mass transfer. This paper presents the influence of penetration mass transfer on the carbonation. A penetration-reaction carbonation model was constructed and validated by accelerated test results under high pressure. Then the characteristics of wind pressure on the carbonation were investigated through finite element analysis considering steady and fluctuating wind flows. The results indicate that the wind pressure on the surface of concrete buildings results in deeper carbonation depth than that just considering the diffusion of carbon dioxide. In addition, the influence of wind pressure on carbonation tends to increase significantly with carbonation depth.

  4. 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)

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Solar wind dynamic pressure variations and transient magnetospheric signatures

    International Nuclear Information System (INIS)

    Sibeck, D.G.; Baumjohann, W.

    1989-01-01

    Contrary to the prevailing popular view, we find some transient ground events with bipolar north-south signatures are related to variations in solar wind dynamic pressure and not necessarily to magnetic merging. We present simultaneous solar wind plasma observations for two previously reported transient ground events observed at dayside auroral latitudes. During the first event, originally reported by Lanzerotti et al. [1987], conjugate ground magnetometers recorded north-south magetic field deflections in the east-west and vertical directions. The second event was reported by Todd et al. [1986], we noted ground rader observations indicating strong northward then southward ionospheric flows. The events were associated with the postulated signatures of patchy, sporadic, merging of magnetosheath and magnetospheric magnetic field lines at the dayside magnetospause, known as flux transfer events. Conversely, we demonstrate that the event reported by Lanzerotti et al. was accompanied by a sharp increase in solar wind dynamic pressure, a magnetospheric compression, and a consequent ringing of the magnetospheric magnetic field. The event reported by Todd et al. was associated with a brief but sharp increase in the solar wind dynamic pressure. copyright American Geophysical Union 1989

  10. Measurements of UWB Pulse Propagation Along a Wind Turbine Blade at 1 to 20 GHz

    DEFF Research Database (Denmark)

    Hejselbæk, Johannes; Syrytsin, Igor A.; Eggers, Patrick Claus F.

    2018-01-01

    This paper describes propagation measurements of an Ultra Wide Band (UWB) pulse along a full-scale wind turbine blade. The aim is to use the UWB channel characteristics to determine the deflection of the wind turbine blade under different wind loads. The frequency response is measured from 1 to 20...... the reflection originates a ray-tracing study incorporating a model of the curvature of the blade have been conducted. This showed the area causing the reflections depended highly on the placement of the antenna on the wind turbine blade....

  11. 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.

  12. 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.

  13. Corotating pressure waves without streams in the solar wind

    International Nuclear Information System (INIS)

    Burlaga, L.F.

    1983-01-01

    Voyager 1 and 2 magnetic field and plasma data are presented which demonstrate the existence of large scale, corotating, non-linear pressure waves between 2 AU and 4 AU that are not accompanied by fast streams. The pressure waves are presumed to be generated by corotating streams near the Sun. For two of the three pressure waves that are discussed, the absence of a stream is probably a real, physical effect, viz., a consequence of deceleration of the stream by the associated compression wave. For the third pressure wave, the apparent absence of a stream may be a geometrical effect it is likely that the stream was at latitudes just above those of the spacecraft, while the associated shocks and compression wave extended over a broader range of latitudes so that they could be observed by the spacecraft. It is suggested that the development of large-scale non-linear pressure waves at the expense of the kinetic energy of streams produces a qualitative change in the solar wind in the outer heliosphere. Within a few AU the quasi-stationary solar wind structure is determined by corotating streams whose structure is determined by the boundary conditions near the Sun

  14. 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

  15. 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.

  16. 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...

  17. Wind gust measurements using pulsed Doppler wind-lidar: comparison of direct and indirect techniques

    DEFF Research Database (Denmark)

    The measurements of wind gusts, defined as short duration wind speed maxima, have traditionally been limited by the height that can be reached by weather masts. Doppler lidars can potentially provide information from levels above this and thereby fill this gap in our knowledge. To measure the 3D...... is 3.9 s) which can provide high resolution turbulent measurements, both in the vertical direction, and potentially in the horizontal direction. In this study we explore different strategies of wind lidar measurements to measure the wind speed maxima. We use a novel stochastic turbulence reconstruction...... model, driven by the Doppler lidar measurements, which uses a non-linear particle filter to estimate the small-scale turbulent fluctuations. The first results show that the reconstruction method can reproduce the wind speed maxima measured by the sonic anemometer if a low-pass filter with a cut...

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2005-06-01

    Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 RE (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= $T_{p, perp}/T_{p, parallel}{-}1$ became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the

  3. Magnetosheath waves under very low solar wind dynamic pressure: Wind/Geotail observations

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2005-06-01

    Full Text Available The expanded bow shock on and around "the day the solar wind almost disappeared" (11 May 1999 allowed the Geotail spacecraft to make a practically uninterrupted 54-h-long magnetosheath pass near dusk (16:30-21:11 magnetic local time at a radial distance of 24 to 30 RE (Earth radii. During most of this period, interplanetary parameters varied gradually and in such a way as to give rise to two extreme magnetosheath structures, one dominated by magnetohydrodynamic (MHD effects and the other by gas dynamic effects. We focus attention on unusual features of electromagnetic ion wave activity in the former magnetosheath state, and compare these features with those in the latter. Magnetic fluctuations in the gas dynamic magnetosheath were dominated by compressional mirror mode waves, and left- and right-hand polarized electromagnetic ion cyclotron (EIC waves transverse to the background field. In contrast, the MHD magnetosheath, lasting for over one day, was devoid of mirror oscillations and permeated instead by EIC waves of weak intensity. The weak wave intensity is related to the prevailing low solar wind dynamic pressures. Left-hand polarized EIC waves were replaced by bursts of right-hand polarized waves, which remained for many hours the only ion wave activity present. This activity occurred when the magnetosheath proton temperature anisotropy (= became negative. This was because the weakened bow shock exposed the magnetosheath directly to the (negative temperature anisotropy of the solar wind. Unlike the normal case studied in the literature, these right-hand waves were not by-products of left-hand polarized waves but derived their energy source directly from the magnetosheath temperature anisotropy. Brief entries into the low latitude boundary layer (LLBL and duskside magnetosphere occurred under such inflated conditions that the magnetospheric magnetic pressure was insufficient to maintain pressure balance. In these crossings, the inner edge of

  4. Expert judgment study on wind pressure coefficients. Part 2 : Unprocessed data: Expert rationales Wind tunnel data. Final report

    NARCIS (Netherlands)

    De Wit, S.

    1999-01-01

    In the design of low-rise buildings, wind tunnel experiments are scarcely employed to assess the wind-induced pressures, which are required e.g. for the simulation of ventilation flows or for the evaluation of the structural integrity. Instead, techniques are used, which predominandy rely on inter-

  5. Latitudinal distribution of the solar wind properties in the low- and high-pressure regimes: Wind observations

    Directory of Open Access Journals (Sweden)

    C. Lacombe

    Full Text Available The solar wind properties depend on λ, the heliomagnetic latitude with respect to the heliospheric current sheet (HCS, more than on the heliographic latitude. We analyse the wind properties observed by Wind at 1 AU during about 2.5 solar rotations in 1995, a period close to the last minimum of solar activity. To determine λ, we use a model of the HCS which we fit to the magnetic sector boundary crossings observed by Wind. We find that the solar wind properties mainly depend on the modulus |λ|. But they also depend on a local parameter, the total pressure (magnetic pressure plus electron and proton thermal pressure. Furthermore, whatever the total pressure, we observe that the plasma properties also depend on the time: the latitudinal gradients of the wind speed and of the proton temperature are not the same before and after the closest HCS crossing. This is a consequence of the dynamical stream interactions. In the low pressure wind, at low |λ|, we find a clear maximum of the density, a clear minimum of the wind speed and of the proton temperature, a weak minimum of the average magnetic field strength, a weak maximum of the average thermal pressure, and a weak maximum of the average β factor. This overdense sheet is embedded in a density halo. The latitudinal thickness is about 5° for the overdense sheet, and 20° for the density halo. The HCS is thus wrapped in an overdense sheet surrounded by a halo, even in the non-compressed solar wind. In the high-pressure wind, the plasma properties are less well ordered as functions of the latitude than in the low-pressure wind; the minimum of the average speed is seen before the HCS crossing. The latitudinal thickness of the high-pressure region is about 20°. Our observations are qualitatively consistent with the numerical model of Pizzo for the deformation of the heliospheric current sheet and plasma sheet.

    Key words: Interplanetary physics (solar wind

  6. 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

  7. Investigation of the spatial variability and possible origins of wind-induced air pressure fluctuations responsible for pressure pumping

    Science.gov (United States)

    Mohr, Manuel; Laemmel, Thomas; Maier, Martin; Zeeman, Matthias; Longdoz, Bernard; Schindler, Dirk

    2017-04-01

    The exchange of greenhouse gases between the soil and the atmosphere is highly relevant for the climate of the Earth. Recent research suggests that wind-induced air pressure fluctuations can alter the soil gas transport and therefore soil gas efflux significantly. Using a newly developed method, we measured soil gas transport in situ in a well aerated forest soil. Results from these measurements showed that the commonly used soil gas diffusion coefficient is enhanced up to 30% during periods of strong wind-induced air pressure fluctuations. The air pressure fluctuations above the forest floor are only induced at high above-canopy wind speeds (> 5 m s-1) and lie in the frequency range 0.01-0.1 Hz. Moreover, the amplitudes of air pressure fluctuations in this frequency range show a clear quadratic dependence on mean above-canopy wind speed. However, the origin of these wind-induced pressure fluctuations is still unclear. Airflow measurements and high-precision air pressure measurements were conducted at three different vegetation-covered sites (conifer forest, deciduous forest, grassland) to investigate the spatial variability of dominant air pressure fluctuations, their origin and vegetation-dependent characteristics. At the conifer forest site, a vertical profile of air pressure fluctuations was measured and an array consisting of five pressure sensors were installed at the forest floor. At the grassland site, the air pressure measurements were compared with wind observations made by ground-based LIDAR and spatial temperature observations from a fibre-optic sensing network (ScaleX Campaign 2016). Preliminary results show that at all sites the amplitudes of relevant air pressure fluctuations increase with increasing wind speed. Data from the array measurements reveal that there are no time lags between the air pressure signals of different heights, but a time lag existed between the air pressure signals of the sensors distributed laterally on the forest floor

  8. Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations

    Science.gov (United States)

    Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.

    2012-12-01

    The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.

  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. 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

  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. 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.

  13. 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.)

  14. 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

  15. 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

  16. 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.

  17. Wind pressure testing of tornado safe room components made from wood

    Science.gov (United States)

    Robert Falk; Deepak Shrestha

    2016-01-01

    To evaluate the ability of a wood tornado safe room to resist wind pressures produced by a tornado, two safe room com-ponents were tested for wind pressure strength. A tornado safe room ceiling panel and door were static-pressure-tested according to ASTM E 330 using a vacuum test system. Re-sults indicate that the panels had load capacities from 2.4 to 3.5 times that...

  18. 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

  19. Field measurement of wind pressure and wind-induced vibration of large-span spatial cable-truss system under strong wind or typhoon

    Directory of Open Access Journals (Sweden)

    ZHANG Zhihong

    2013-10-01

    Full Text Available In order to ensure wind-resistance safety of large-span pre-stressed flexible system in southeast coast area of China,and to prepare something for revising of current codes of practice or technical standards,the present paper conducts field measurement of wind pressure and wind-induced vibration of a practical and typical large-span spatial cable-truss system-lunar stadium in Yueqing city.Wind loading and wind effects on full-scale structure under strong wind or typhoon in real architectural environment can be obtained directly and effectively.Field measurement is the best way to investigate the wind loading property,wind effects,and wind-structure interactions of large-span flexible system.Measured data will be highly valuable for scientific research and practical design.On the other hand,it also provides the basis of wind-resistance safety design of this kind of tension structures.If any creative development,it would dramatically improve the research level of large-span pre-stressed flexible system in our country.

  20. 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%.

  1. Pulse-burst PIV in a high-speed wind tunnel

    International Nuclear Information System (INIS)

    Beresh, Steven; Kearney, Sean; Wagner, Justin; Guildenbecher, Daniel; Henfling, John; Spillers, Russell; Pruett, Brian; Jiang, Naibo; Slipchenko, Mikhail; Mance, Jason; Roy, Sukesh

    2015-01-01

    Time-resolved particle image velocimetry (TR-PIV) has been achieved in a high-speed wind tunnel, providing velocity field movies of compressible turbulence events. The requirements of high-speed flows demand greater energy at faster pulse rates than possible with the TR-PIV systems developed for low-speed flows. This has been realized using a pulse-burst laser to obtain movies at up to 50 kHz, with higher speeds possible at the cost of spatial resolution. The constraints imposed by use of a pulse-burst laser are limited burst duration of 10.2 ms and a low duty cycle for data acquisition. Pulse-burst PIV has been demonstrated in a supersonic jet exhausting into a transonic crossflow and in transonic flow over a rectangular cavity. The velocity field sequences reveal the passage of turbulent structures and can be used to find velocity power spectra at every point in the field, providing spatial distributions of acoustic modes. The present work represents the first use of TR-PIV in a high-speed ground-test facility. (paper)

  2. 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)

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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 ...

  9. Galactic Winds Driven by Supernovae and Radiation Pressure: Theory and Simulations

    Science.gov (United States)

    Zhang, Dong; Davis, Shane

    2018-01-01

    Galactic winds are ubiquitous in most rapidly star-forming galaxies. They are crucial to the process of galaxy formation and evolution, regulating star formation, shaping the stellar mass function and the mass-metallicity relation, and enriching the intergalactic medium with metals. Although important, the physics of galactic winds is still unclear. Winds may be driven by many mechanisms including overlapping supernovae explosions, radiation pressure of starlight on dust grains, and cosmic rays. However, the growing observations of multiphase structure in galactic winds in a large number of galaxies have not been well explained by any models. In this talk I will focus on the models of supernova- and radiation-pressure-driven winds. Using the state-of-the-art numerical simulations, I will assess the relative merits of these driving mechanisms for accelerating cold and warm clouds to observed velocities, and momentum flux boost during wind propagation.

  10. 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.

  11. 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.

  12. 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

  13. Near 7-day response of ocean bottom pressure to atmospheric surface pressure and winds in the northern South China Sea

    Science.gov (United States)

    Zhang, Kun; Zhu, Xiao-Hua; Zhao, Ruixiang

    2018-02-01

    Ocean bottom pressures, observed by five pressure-recording inverted echo sounders (PIESs) from October 2012 to July 2014, exhibit strong near 7-day variability in the northern South China Sea (SCS) where long-term in situ bottom pressure observations are quite sparse. This variability was strongest in October 2013 during the near two years observation period. By joint analysis with European Center for Medium-Range Weather Forecasts (ECMWF) data, it is shown that the near 7-day ocean bottom pressure variability is closely related to the local atmospheric surface pressure and winds. Within a period band near 7 days, there are high coherences, exceeding 95% significance level, of observed ocean bottom pressure with local atmospheric surface pressure and with both zonal and meridional components of the wind. Ekman pumping/suction caused by the meridional component of the wind in particular, is suggested as one driving mechanism. A Kelvin wave response to the near 7-day oscillation would propagate down along the continental slope, observed at the Qui Nhon in the Vietnam. By multiple and partial coherence analyses, we find that local atmospheric surface pressure and Ekman pumping/suction show nearly equal influence on ocean bottom pressure variability at near 7-day periods. A schematic diagram representing an idealized model gives us a possible mechanism to explain the relationship between ocean bottom pressure and local atmospheric forcing at near 7-day periods in the northern SCS.

  14. A novel structure of transmission line pulse transformer with mutually coupled windings.

    Science.gov (United States)

    Yu, Binxiong; Su, Jiancang; Li, Rui; Zhao, Liang; Zhang, Xibo; Wang, Junjie

    2014-03-01

    A novel structure of transmission line transformer (TLT) with mutually coupled windings is described in this paper. All transmission lines except the first stage of the transformer are wound on a common ferrite core for the TLT with this structure. A referral method was introduced to analyze the TLT with this structure, and an analytic expression of the step response was derived. It is shown that a TLT with this structure has a significantly slower droop rate than a TLT with other winding structures and the number of ferrite cores needed is largely reduced. A four-stage TLT with this structure was developed, whose input and output impedance were 4.2 Ω and 67.7 Ω, respectively. A frequency response test of the TLT was carried out. The test results showed that pulse response time of the TLT is several nanoseconds. The TLT described in this paper has the potential to be used as a rectangle pulse transformer with very fast response time.

  15. Residential tornado safe room from commodity wood products – impact and wind pressure testing

    Science.gov (United States)

    Robert H. Falk; James J. Bridwell; C. Adam Senalik; Marshall Begel

    2018-01-01

    A tornado safe room is a shelter designed to provide protection during a tornado and is specifically engineered to resist the high wind pressures and debris impact generated by these high wind events. The required performance criteria of these shelters has been established and is found in the International Code Council Standard for the Design and Construction of Storm...

  16. An experimental investigation of wind pressures on square pillars in tornado-like vortices

    International Nuclear Information System (INIS)

    Iwatani, Yoshiharu; Maruta, Eizou; Kanda, Makoto; Hattori, Yousuke; Hamano, Naoki; Matsuura, Takeshi

    1992-01-01

    This report describes a laboratory simulation of tornado-like vortices and laboratory measurements of steady wind loads on model structures in tornado-like vortices. The variations of wind direction and wind speed of tornado-like vortices and ground surface pressure under tornado-like vortices with the swirl ratio, Reynolds number and the surface roughness were investigated. Wind pressure distributions on square pillars were measured in tornado-like vortices. It was observed in the experiment that the negative pressures on the roof faces of square pillars were high and distributed rather uniformly but these on the side faces differed greatly from place to place and locally became high. The high pressure regions on the side faces were close to ground surface in the case where the model structures stood in the center of tornado-like vortex, and became higher as the increase of distance between the model structures and the center of tornado-like vortices. (author)

  17. 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...

  18. Ionospheric cusp flows pulsed by solar wind Alfvén waves

    Directory of Open Access Journals (Sweden)

    P. Prikryl

    2002-02-01

    Full Text Available Pulsed ionospheric flows (PIFs in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs. The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is concluded that on these occasions, the FTEs were driven by Alfvén waves coupling to the day-side magnetosphere. Case studies are presented in which the dawn-dusk component of the Alfvén wave electric field modulates the reconnection rate as evidenced by the radar observations of the ionospheric cusp flows. The arrival of the IMF southward turning at the magnetopause is determined from multipoint solar wind magnetic field and/or plasma measurements, assuming plane phase fronts in solar wind. The cross-correlation lag between the solar wind data and ground magnetograms that were obtained near the cusp footprint exceeded the estimated spacecraft-to-magnetopause propagation time by up to several minutes. The difference can account for and/or exceeds the Alfvén propagation time between the magnetopause and ionosphere. For the case of short period ( < 13 min PIFs, the onset times of the flow transients appear to be further delayed by at most a few more minutes after the IMF southward turning arrived at the magnetopause. For the case of long period (30 – 40 min PIFs, the observed additional delays were 10–20 min. We interpret the excess delay in terms of an intrinsic time scale for reconnection (Russell et al., 1997 which can be explained by the surface-wave induced magnetic reconnection mechanism (Uberoi et al., 1999. Here, surface waves with wavelengths larger than the thickness of the neutral layer induce a tearing-mode instability whose rise time explains the

  19. 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.

  20. 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.

  1. Converting Wind Energy to Ammonia at Lower Pressure

    International Nuclear Information System (INIS)

    Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

    2017-01-01

    Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

  2. 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

  3. Design of a new urban wind turbine airfoil using a pressure-load inverse method

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, J.C.C.; Gato, L.M.C. [IDMEC, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Marques da Silva, F. [LNEC - Laboratorio Nacional de Engenharia Civil, Av. Brasil, 101, 1700-066 Lisboa (Portugal); Estanqueiro, A.I. [INETI - Instituto Nacional de Engenharia, Tecnologia e Inovacao Estrada do Paco do Lumiar, 1649-038 Lisboa (Portugal)

    2009-12-15

    This paper presents the design methodology of a new wind turbine airfoil that achieves high performance in urban environment by increasing the maximum lift. For this purpose, an inverse method was applied to obtain a new wind turbine blade section with constant pressure-load along the chord, at the design inlet angle. In comparison with conventional blade section designs, the new airfoil has increased maximum lift, reduced leading edge suction peak and controlled soft-stall behaviour, due to a reduction of the adverse pressure gradient on the suction side. Wind tunnel experimental results confirmed the computational results. (author)

  4. 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.

  5. 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.

  6. 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

  7. Aerodynamic Response of a Pitching Airfoil with Pulsed Circulation Control for Vertical Axis Wind Turbine Applications

    Science.gov (United States)

    Panther, Chad C.

    Vertical Axis Wind Turbines (VAWTs) have experienced a renewed interest in development for urban, remote, and offshore applications. Past research has shown that VAWTs cannot compete with Horizontals Axis Wind Turbines (HAWTs) in terms of energy capture efficiency. VAWT performance is plagued by dynamic stall (DS) effects at low tip-speed ratios (lambda), where each blade pitches beyond static stall multiple times per revolution. Furthermore, for lambdaoperate outside of stall during over 70% of rotation. However, VAWTs offer many advantages such as omnidirectional operation, ground proximity of generator, lower sound emission, and non-cantilevered blades with longer life. Thus, mitigating dynamic stall and improving VAWT blade aerodynamics for competitive power efficiency has been a popular research topic in recent years and the directive of this study. Past research at WVU focused on the addition of circulation control (CC) technology to improve VAWT aerodynamics and expand the operational envelope. A novel blade design was generated from the augmentation of a NACA0018 airfoil to include CC capabilities. Static wind tunnel data was collected for a range of steady jet momentum coefficients (0.01≤ Cmu≤0.10) for analytical vortex model performance projections. Control strategies were developed to optimize CC jet conditions throughout rotation, resulting in improved power output for 2≤lambda≤5. However, the pumping power required to produce steady CC jets reduced net power gains of the augmented turbine by approximately 15%. The goal of this work was to investigate pulsed CC jet actuation to match steady jet performance with reduced mass flow requirements. To date, no experimental studies have been completed to analyze pulsed CC performance on a pitching airfoil. The research described herein details the first study on the impact of steady and pulsed jet CC on pitching VAWT blade aerodynamics. Both numerical and experimental studies were implemented, varying

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Wind pressure loading for tall buidings: a case study of Warsaw Trade Tower

    CSIR Research Space (South Africa)

    Cwik, M

    2012-12-01

    Full Text Available of the building model and its surroundings, as well as the testing methods are described. The second part provides a description of the evaluation of the extreme pressure values using Gumbel distribution. Minimum and maximum wind pressure patterns over facade...

  17. 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

  18. 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.)

  19. 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.

  20. 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.

  1. 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

  2. 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):.

  3. 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.

  4. 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...

  5. 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.

  6. Effects of the Solar Wind Pressure on Mercury's Exosphere: Hybrid Simulations

    Science.gov (United States)

    Travnicek, P. M.; Schriver, D.; Orlando, T. M.; Hellinger, P.

    2017-12-01

    We study effects of the changed solar wind pressure on the precipitation of hydrogen on the Mercury's surface and on the formation of Mercury's magnetosphere. We carry out a set of global hybrid simulations of the Mercury's magnetosphere with the interplanetary magnetic field oriented in the equatorial plane. We change the solar wind pressure by changing the velocity of injected solar wind plasma (vsw = 2 vA,sw; vsw = 4 vA,sw; vsw = 6 vA,sw). For each of the cases we examine proton and electron precipitation on Mercury's surface and calculate yields of heavy ions released from Mercury's surface via various processes (namely: Photo-Stimulated Desorption, Solar Wind Sputtering, and Electron Stimulated Desorption). We study circulation of the released ions within the Mercury's magnetosphere for the three cases.

  7. 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.

  8. 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.

  9. Effects of Abrupt Variations of Solar Wind Dynamic Pressure on the High-Latitude Ionosphere

    Directory of Open Access Journals (Sweden)

    Igino Coco

    2011-01-01

    Full Text Available We show the results of a statistical study on the effects in the high-latitude ionosphere of abrupt variations of solar wind dynamic pressure, using Super Dual Auroral Radar Network (SuperDARN data in both hemispheres. We find that, during periods of quiet ionospheric conditions, the amount of radar backscatter increases when a variation in the dynamic pressure occurs, both positive (increase of the pressure and negative (decrease of the pressure. We also investigate the behaviour of the Cross-Polar Cap Potential (CPCP during pressure variations and show preliminary results.

  10. THE EFFECT OF ELECTRON THERMAL PRESSURE ON THE OBSERVED MAGNETIC HELICITY IN THE SOLAR WIND

    Energy Technology Data Exchange (ETDEWEB)

    Markovskii, S. A.; Vasquez, Bernard J.; Smith, Charles W., E-mail: sergei.markovskii@unh.edu, E-mail: bernie.vasquez@unh.edu, E-mail: charles.smith@unh.edu [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)

    2016-12-20

    Statistical analysis of magnetic helicity spectra in the solar wind at 1 au is carried out. A large database of the solar wind intervals assembled from Wind spacecraft magnetic and plasma data is used. The effect of the electron thermal pressure on the wavenumber position of the helicity signature, i.e., the peak of the spectrum, is studied. The position shows a statistically significant dependence on both the electron and proton pressures. However, the strongest dependence is seen when the two pressures are summed. These findings confirm that the generation of the magnetic helicity is associated with an increasing compressibility of the turbulent fluctuations at smaller kinetic scales. It is argued that instrumental artifacts do not contribute to the helicity signature.

  11. 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.

  12. The 12-foot pressure wind tunnel restoration project model support systems

    Science.gov (United States)

    Sasaki, Glen E.

    1992-01-01

    The 12 Foot Pressure Wind Tunnel is a variable density, low turbulence wind tunnel that operates at subsonic speeds, and up to six atmospheres total pressure. The restoration of this facility is of critical importance to the future of the U.S. aerospace industry. As part of this project, several state of the art model support systems are furnished to provide an optimal balance between aerodynamic and operational efficiency parameters. Two model support systems, the Rear Strut Model Support, and the High Angle of Attack Model Support are discussed. This paper covers design parameters, constraints, development, description, and component selection.

  13. 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

  14. 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: ...

  15. 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....

  16. 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 ...

  17. 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

  18. 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.

  19. Experimental and numerical characterization of wind-induced pressure coefficients on nuclear buildings and chimney exhausts

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, Laurent, E-mail: laurent.ricciardi@irsn.fr; Gélain, Thomas; Soares, Sandrine

    2015-10-15

    Highlights: • Experiments on scale models of nuclear buildings and chimney exhausts were performed. • Pressure coefficient fields on buildings are shown for various wind directions. • Evolution of pressure coefficient vs U/W ratio is given for various chimney exhausts. • RANS simulations using SST k–ω turbulence model were performed on most studied cases. • A good agreement is overall observed, with Root Mean Square Deviation lower than 0.15. - Abstract: Wind creates pressure effects on different surfaces of buildings according to their exposure to the wind, in particular at external communications. In nuclear facilities, these effects can change contamination transfers inside the building and can even lead to contamination release into the environment, especially in damaged (ventilation stopped) or accidental situations. The diversity of geometries of facilities requires the use of a validated code for predicting pressure coefficients, which characterize the wind effect on the building walls and the interaction between the wind and chimney exhaust. The first aim of a research program launched by the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN), was therefore to acquire experimental data of the mean pressure coefficients for different geometries of buildings and chimneys through wind tunnel tests and then to validate a CFD code (ANSYS CFX) from these experimental results. The simulations were performed using a steady RANS approach and a two-equation SST k–ω turbulence model. After a mesh sensitivity study for one configuration of building and chimney, a comparison was carried out between the numerical and experimental values for other studied configurations. This comparison was generally satisfactory, averaged over all measurement points, with values of Root Mean Square Deviations lower than 0.15 for most cases.

  20. Direct monitoring of wind-induced pressure-pumping on gas transport in soil

    Science.gov (United States)

    Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

    2017-04-01

    Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non

  1. 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....

  2. 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.)

  3. 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...

  4. 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.

  5. 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)

  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. INVESTINGATION DOWNWARD WIND PRESSURE ON A SMALL QUADROTOR HELICOPTER

    OpenAIRE

    RAHMATI, Sadegh; GHASED, Amir

    2015-01-01

    Abstract. Small rotary-wing UAVs are susceptible to gusts and other environmental disturbances that affect inflow at their rotors. Inflow variations cause unexpected aerodynamic forces through changes in thrust conditions and unmodeled blade-flapping dynamics. This pa­per introduces an onboard, pressure-based flow measurement system developed for a small quadrotor helicopter. The probe-based instrumentation package provides spatially dis­tributed airspeed measurements along each of the aircra...

  8. 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

  9. 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.

  10. 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.

  11. Hypersonic Wind-Tunnel Measurements of Boundary-Layer Pressure Fluctuations

    Science.gov (United States)

    2009-08-01

    Fluctuation Cone The Pressure-Fluctuation Cone was used for all wind-tunnel tests (Figure 3.7). The model is a 7◦ half-angle stainless - steel cone. It...analysis as a medium for fault detection: A review. Journal of Tribology , 130, January 2008. [80] L. M. Mack. Boundary layer linear stability theory. In

  12. 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.

  13. 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

  14. Extreme pressure differences at 0900 NZST and winds across New Zealand

    Science.gov (United States)

    Salinger, M. James; Griffiths, Georgina M.; Gosai, Ashmita

    2005-07-01

    Trends in extremes in station daily sea-level pressure differences at 0900 NZST are examined, and extreme daily wind gusts, across New Zealand, since the 1960s. Annual time series were examined (with indices of magnitude and frequency over threshold percentiles) from the daily indices selected. These follow from earlier indices of normalized monthly mean sea-level pressure differences between station pairs, except the daily indices are not normalized. The frequency statistics quantify the number of extreme zonal (westerly and easterly), or extreme meridional (southerly or northerly), pressure gradient events. The frequency and magnitude of extreme westerly episodes has increased slightly over New Zealand, with a significant increase in the westerly extremes to the south of New Zealand. In contrast, the magnitude and frequency of easterly extremes has decreased over New Zealand, but increased to the south, with some trends weakly significant. The frequency and magnitude of daily southerly extremes has decreased significantly in the region.Extreme daily wind gust events at key climate stations in New Zealand and at Hobart, Australia, are highly likely to be associated with an extreme daily pressure difference. The converse was less likely to hold: extreme wind gusts were not always observed on days with extreme daily pressure difference, probably due to the strong influence that topography has on localized station winds. Significant correlations exist between the frequency indices and both annual-average mean sea-level pressures around the Australasian region and annual-average sea surface temperature (SST) anomalies in the Southern Hemisphere. These correlations are generally stronger for indices of extreme westerly or extreme southerly airflows. Annual-average pressures in the Tasman Sea or Southern Ocean are highly correlated to zonal indices (frequency of extreme westerlies). SST anomalies in the NINO3 region or on either side of the South Island are

  15. Multiscale wind cycles and current pulses at the Black Sea eastern boundary

    Science.gov (United States)

    Melnikov, Vasiliy; Moskalenko, Lidija; Piotoukh, Vladimir; Zatsepin, Andrey

    2015-04-01

    quantified anomalies, associated with different frequency components of variability, such as sub-meso-scale eddies, marginal shelf waves, inertial oscillations, diurnal, semi-diurnal and short-period internal waves, long surface waves, were estimated. Based on estimates of the statistical relationships between the different parameters of hydro-meteorological system, including meteorological elements, sea level, sea temperature and flow fields, space/time scales of the observed fields variability were estimated. Several new features of the physical mechanisms of multiscale hydro-physical processes in the shelf zone of the Black Sea, have been revealed. In particular, it is shown, that there are wind self-similar cycles at different time scales, each cycle being consisted of a pair of northeast and then southeast winds, which corresponds to the alternative influences of the Azores and Siberian highs(in winter). In the range of decadal (10 years) scale and in macro space view, long-term wind cycles support basic Black Sea circulation(Rim Current).Wind cycles with a time scale of about 20 days give rise to distinct upwellings, appeared with the same frequency. Along with each upwelling, radical hydrological restructuring of the stratification is accompanied by intense advection with high velocities(up to 1 m/s). Kinetic energy is dominated by alongshore currents, the direction being reversed periodically. The vertical structure of currents is rather complicated. When the current speed exceeds some threshold value, the flow gives rise to relaxation oscillations with a period of about 24 hours with counterclockwise velocity vector rotation. All the above mentioned events and current pulses cause significant variations of air-sea fluxes. This research was jointly supported by Ministry of Education of the RF (Agreement №14.604.21.0044), Russian Academy of Sciences(Program No 23), RFBR grant 14-05-00159,contract No 10/2013 RGS-RFBR.

  16. 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.

  17. 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.

  18. Large fog collectors: New strategies for collection efficiency and structural response to wind pressure

    Science.gov (United States)

    Holmes, Robert; Rivera, Juan de Dios; de la Jara, Emilio

    2015-01-01

    Most studies of large fog collectors (LFC) have focused on the collection efficiency, the amount of water collected, or economic and social aspects, but have not addressed the effects of strong winds on the system. Wind pressure is directly related to fog water collection efficiency but on the other hand may cause serious damage on the structure of LFCs. This study focuses in the effects of wind pressure on the components of the LFC as an integral system, and the ways to face strong winds with no significant damage. For this purpose we analysed cases of mechanical failure of LFCs both in our experimental station at Peña Blanca in Chile and elsewhere. The effects of wind pressure can be described as a sequence of physical processes, starting with the mesh deformation as a way of adapting to the induced stresses. For a big enough pressure, local stress concentrations generate a progressive rupture of the mesh. In cases where the mesh is sufficiently strong the wind force causes the partial or total collapse of the structure. Usually the weakest part is the mesh, especially close to where it is attached to the structure. The way the mesh is attached to the frame or cable of the structure is particularly important since it can induce significant stress concentrations. Mesh failure before the structure failure may be considered as a mechanical fuse, since it is cheaper to repair. However, more practical mechanical fuses can be conceived. In relation to structural performance and water collection efficiency, we propose a new design strategy that considers a three-dimensional spatial display of the collection screen, oblique incidence angle of wind on mesh and small mesh area between the supporting frame. The proposed design strategies consider both the wind pressure on mesh and structure and the collection efficiency as an integral solution for the LFC. These new design strategies are the final output of this research. Applying these strategies a multi-funnel LFC is

  19. 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.

  20. 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)

  1. 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.

  2. 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

  3. 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.

  4. Use of Active Learning to Design Wind Tunnel Runs for Unsteady Cavity Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Ankur Srivastava

    2014-01-01

    Full Text Available Wind tunnel tests to measure unsteady cavity flow pressure measurements can be expensive, lengthy, and tedious. In this work, the feasibility of an active machine learning technique to design wind tunnel runs using proxy data is tested. The proposed active learning scheme used scattered data approximation in conjunction with uncertainty sampling (US. We applied the proposed intelligent sampling strategy in characterizing cavity flow classes at subsonic and transonic speeds and demonstrated that the scheme has better classification accuracies, using fewer training points, than a passive Latin Hypercube Sampling (LHS strategy.

  5. 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 .

  6. 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}.

  7. 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. ...

  8. 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

  9. 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)

  10. 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.

  11. 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.

  12. Background Pressure Profiles for Sonic Boom Vehicle Testing in the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel

    Science.gov (United States)

    Castner, Raymond; Shaw, Stephen; Adamson, Eric; Simerly, Stephanie

    2013-01-01

    In an effort to identify test facilities that offer sonic boom measurement capabilities, an exploratory test program was initiated using wind tunnels at NASA research centers. The subject of this report is the sonic boom pressure rail data collected in the Glenn Research Center 8- by 6-Foot Supersonic Wind Tunnel. The purpose is to summarize the lessons learned based on the test activity, specifically relating to collecting sonic boom data which has a large amount of spatial pressure variation. The wind tunnel background pressure profiles are presented as well as data which demonstrated how both wind tunnel Mach number and model support-strut position affected the wind tunnel background pressure profile. Techniques were developed to mitigate these effects and are presented.

  13. 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

  14. 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.

  15. Atmospheric pressure, density, temperature and wind variations between 50 and 200 km

    Science.gov (United States)

    Justus, C. G.; Woodrum, A.

    1972-01-01

    Data on atmospheric pressure, density, temperature and winds between 50 and 200 km were collected from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others. These data were analyzed by a daily difference method and results on the distribution statistics, magnitude, and spatial structure of the irregular atmospheric variations are presented. Time structures of the irregular variations were determined by the analysis of residuals from harmonic analysis of time series data. The observed height variations of irregular winds and densities are found to be in accord with a theoretical relation between these two quantities. The latitude variations (at 50 - 60 km height) show an increasing trend with latitude. A possible explanation of the unusually large irregular wind magnitudes of the White Sands MRN data is given in terms of mountain wave generation by the Sierra Nevada range about 1000 km west of White Sands. An analytical method is developed which, based on an analogy of the irregular motion field with axisymmetric turbulence, allows measured or model correlation or structure functions to be used to evaluate the effective frequency spectra of scalar and vector quantities of a spacecraft moving at any speed and at any trajectory elevation angle.

  16. Current Sheets in Pulsar Magnetospheres and Winds: Particle Acceleration and Pulsed Gamma Ray Emission

    Science.gov (United States)

    Arons, Jonathan

    The research proposed addresses understanding of the origin of non-thermal energy in the Universe, a subject beginning with the discovery of Cosmic Rays and continues, including the study of relativistic compact objects - neutron stars and black holes. Observed Rotation Powered Pulsars (RPPs) have rotational energy loss implying they have TeraGauss magnetic fields and electric potentials as large as 40 PetaVolts. The rotational energy lost is reprocessed into particles which manifest themselves in high energy gamma ray photon emission (GeV to TeV). Observations of pulsars from the FERMI Gamma Ray Observatory, launched into orbit in 2008, have revealed 130 of these stars (and still counting), thus demonstrating the presence of efficient cosmic accelerators within the strongly magnetized regions surrounding the rotating neutron stars. Understanding the physics of these and other Cosmic Accelerators is a major goal of astrophysical research. A new model for particle acceleration in the current sheets separating the closed and open field line regions of pulsars' magnetospheres, and separating regions of opposite magnetization in the relativistic winds emerging from those magnetopsheres, will be developed. The currents established in recent global models of the magnetosphere will be used as input to a magnetic field aligned acceleration model that takes account of the current carrying particles' inertia, generalizing models of the terrestrial aurora to the relativistic regime. The results will be applied to the spectacular new results from the FERMI gamma ray observatory on gamma ray pulsars, to probe the physics of the generation of the relativistic wind that carries rotational energy away from the compact stars, illuminating the whole problem of how compact objects can energize their surroundings. The work to be performed if this proposal is funded involves extending and developing concepts from plasma physics on dissipation of magnetic energy in thin sheets of

  17. 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.

  18. 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.

  19. Time-Accurate Unsteady Pressure Loads Simulated for the Space Launch System at Wind Tunnel Conditions

    Science.gov (United States)

    Alter, Stephen J.; Brauckmann, Gregory J.; Kleb, William L.; Glass, Christopher E.; Streett, Craig L.; Schuster, David M.

    2015-01-01

    A transonic flow field about a Space Launch System (SLS) configuration was simulated with the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics (CFD) code at wind tunnel conditions. Unsteady, time-accurate computations were performed using second-order Delayed Detached Eddy Simulation (DDES) for up to 1.5 physical seconds. The surface pressure time history was collected at 619 locations, 169 of which matched locations on a 2.5 percent wind tunnel model that was tested in the 11 ft. x 11 ft. test section of the NASA Ames Research Center's Unitary Plan Wind Tunnel. Comparisons between computation and experiment showed that the peak surface pressure RMS level occurs behind the forward attach hardware, and good agreement for frequency and power was obtained in this region. Computational domain, grid resolution, and time step sensitivity studies were performed. These included an investigation of pseudo-time sub-iteration convergence. Using these sensitivity studies and experimental data comparisons, a set of best practices to date have been established for FUN3D simulations for SLS launch vehicle analysis. To the author's knowledge, this is the first time DDES has been used in a systematic approach and establish simulation time needed, to analyze unsteady pressure loads on a space launch vehicle such as the NASA SLS.

  20. 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.

  1. A Wind Tunnel Study on the Mars Pathfinder (MPF) Lander Descent Pressure Sensor

    Science.gov (United States)

    Soriano, J. Francisco; Coquilla, Rachael V.; Wilson, Gregory R.; Seiff, Alvin; Rivell, Tomas

    2001-01-01

    The primary focus of this study was to determine the accuracy of the Mars Pathfinder lander local pressure readings in accordance with the actual ambient atmospheric pressures of Mars during parachute descent. In order to obtain good measurements, the plane of the lander pressure sensor opening should ideally be situated so that it is parallel to the freestream. However, due to two unfavorable conditions, the sensor was positioned in locations where correction factors are required. One of these disadvantages is due to the fact that the parachute attachment point rotated the lander's center of gravity forcing the location of the pressure sensor opening to be off tangent to the freestream. The second and most troublesome factor was that the lander descends with slight oscillations that could vary the amplitude of the sensor readings. In order to accurately map the correction factors required at each sensor position, an experiment simulating the lander descent was conducted in the Martian Surface Wind Tunnel at NASA Ames Research Center. Using a 115 scale model at Earth ambient pressures, the test settings provided the necessary Reynolds number conditions in which the actual lander was possibly subjected to during the descent. In the analysis and results of this experiment, the readings from the lander sensor were converted to the form of pressure coefficients. With a contour map of pressure coefficients at each lander oscillatory position, this report will provide a guideline to determine the correction factors required for the Mars Pathfinder lander descent pressure sensor readings.

  2. 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.

  3. Fatigue damage from random vibration pulse process of tubular structural elements subject to wind

    DEFF Research Database (Denmark)

    Christensen, Claus F.; Ditlevsen, Ove Dalager

    1997-01-01

    In a wide range of the Reynolds number an elastically suspended circular cylinder surrounded by a homogeneous wind velocity field will generate vortex shedding of a frequency that by and large is proportional to the far field wind velocity. However, if the cylinder is free to vibrate, resonance w...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Pedersen, Jørgen Kaas

    1998-01-01

    Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig......Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop...... and investigate the use of a STATCOM by modelling and field testing an 8 MVar unit in a 24 MW wind farm....

  16. 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

  17. Time Accurate Unsteady Pressure Loads Simulated for the Space Launch System at a Wind Tunnel Condition

    Science.gov (United States)

    Alter, Stephen J.; Brauckmann, Gregory J.; Kleb, Bil; Streett, Craig L; Glass, Christopher E.; Schuster, David M.

    2015-01-01

    Using the Fully Unstructured Three-Dimensional (FUN3D) computational fluid dynamics code, an unsteady, time-accurate flow field about a Space Launch System configuration was simulated at a transonic wind tunnel condition (Mach = 0.9). Delayed detached eddy simulation combined with Reynolds Averaged Naiver-Stokes and a Spallart-Almaras turbulence model were employed for the simulation. Second order accurate time evolution scheme was used to simulate the flow field, with a minimum of 0.2 seconds of simulated time to as much as 1.4 seconds. Data was collected at 480 pressure taps at locations, 139 of which matched a 3% wind tunnel model, tested in the Transonic Dynamic Tunnel (TDT) facility at NASA Langley Research Center. Comparisons between computation and experiment showed agreement within 5% in terms of location for peak RMS levels, and 20% for frequency and magnitude of power spectral densities. Grid resolution and time step sensitivity studies were performed to identify methods for improved accuracy comparisons to wind tunnel data. With limited computational resources, accurate trends for reduced vibratory loads on the vehicle were observed. Exploratory methods such as determining minimized computed errors based on CFL number and sub-iterations, as well as evaluating frequency content of the unsteady pressures and evaluation of oscillatory shock structures were used in this study to enhance computational efficiency and solution accuracy. These techniques enabled development of a set of best practices, for the evaluation of future flight vehicle designs in terms of vibratory loads.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Validation of a wind tunnel testing facility for blade surface pressure measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fuglsang, P.; Antoniou, I.; Soerensen, N.N.; Madsen, H.A.

    1998-04-01

    This report concerns development and validation of a 2d testing facility for airfoil pressure measurements. The VELUX open jet wind tunnel was used with a test stand inserted. Reynolds numbers until 1.3 million were achieved with an airfoil chord of 0.45 m. The aerodynamic load coefficients were found from pressure distribution measurements and the total drag coefficient was calculated from wake rake measurements. Stationary inflow as well as dynamic inflow through pitching motion was possible. Wind tunnel corrections were applied for streamline curvature and down-wash. Even though the wind tunnel is not ideal for 2d testing, the overall quality of the flow was acceptable with a uniform flow field at the test stand position and a turbulence intensity of 1 % at the inlet of the test section. Reference values for free stream static and total pressure were found upstream of the test stand. The NACA 63-215 airfoil was tested and the results were compared with measurements from FFA and NACA. The measurements agreed well except for lift coefficient values at high angles of attack and the drag coefficient values at low angles of attack, that were slightly high. Comparisons of the measured results with numerical predictions from the XFOIL code and the EllipSys2D code showed good agreement. Measurements with the airfoil in pitching motion were carried out to study the dynamic aerodynamic coefficients. Steady inflow measurements at high angles of attack were used to investigate the double stall phenomenon. (au) EFP-94; EFP-95; EFP-97. 8 tabs., 82 ills., 16 refs.

  10. Effects of a solar wind dynamic pressure increase in the magnetosphere and in the ionosphere

    Directory of Open Access Journals (Sweden)

    L. Juusola

    2010-10-01

    Full Text Available On 17 July 2005, an earthward bound north-south oriented magnetic cloud and its sheath were observed by the ACE, SoHO, and Wind solar wind monitors. A steplike increase of the solar wind dynamic pressure during northward interplanetary magnetic field conditions was related to the leading edge of the sheath. A timing analysis between the three spacecraft revealed that this front was not aligned with the GSE y-axis, but had a normal (−0.58,0.82,0. Hence, the first contact with the magnetosphere occurred on the dawnside rather than at the subsolar point. Fortunately, Cluster, Double Star 1, and Geotail happened to be distributed close to the magnetopause in this region, which made it possible to closely monitor the motion of the magnetopause. After the pressure front had impacted the magnetosphere, the magnetopause was perceived first to move inward and then immediately to correct the overshoot by slightly expanding again such that it ended up between the Cluster constellation with Double Star 1 inside the magnetosphere and Geotail in the magnetosheath. Coinciding with the inward and subsequent outward motion, the ground-based magnetic field at low latitudes was observed to first strengthen and then weaken. As the magnetopause position stabilised, so did the ground-based magnetic field intensity, settling at a level slightly higher than before the pressure increase. Altogether the magnetopause was moving for about 15 min after its first contact with the front. The high latitude ionospheric signature consisted of two parts: a shorter (few minutes and less intense preliminary part comprised a decrease of AL and a negative variation of PC. A longer (about ten minutes and more intense main part of the signature comprised an increase of AU and a positive variation of PC. Measurements from several ground-based magnetometer networks (210 MM CPMN, CANMOS, CARISMA, GIMA, IMAGE, MACCS, SuperMAG, THEMIS, TGO were used to obtain information on the

  11. Statistical Characteristics of Solar Wind Dynamic Pressure Enhancements During Geomagnetic Storms

    Directory of Open Access Journals (Sweden)

    C.-R. Choi

    2008-06-01

    Full Text Available Solar wind dynamic pressure enhancements are known to cause various types of disturbances to the magnetosphere. In particular, dynamic pressure enhancements may affect the evolution of magnetic storms when they occur during storm times. In this paper, we have investigated the statistical significance and features of dynamic pressure enhancements during magnetic storm times. For the investigation, we have used a total of 91 geomagnetic storms for 2001-2003, for which the Dst minimum (Dst_min is below -50 nT. Also, we have imposed a set of selection criteria for a pressure enhancement to be considered an event: The main selection criterion is that the pressure increases by ≥50% or ≥3nPa within 30 min and remains to be elevated for 10 min or longer. For our statistical analysis, we define the storm time to be the interval from the main Dst decrease, through Dst_min, to the point where the Dst index recovers by 50%. Our main results are summarized as follows. (i ~81% of the studied storms indicate at least one event of pressure enhancements. When averaged over all the 91 storms, the occurrence rate is 4.5 pressure enhancement events per storm and 0.15 pressure enhancement events per hour. (ii The occurrence rate of the pressure enhancements is about three times higher for CME-driven storm times than for CIR-driven storm times. (iii Only 21.1% of the pressure enhancements show a clear association with an interplanetary shock. (iv A large number of the pressure enhancement events are accompanied with a simultaneous change of IMF By and/or Bz: For example, 73.5% of the pressure enhancement events are associated with an IMF change of either |∆Bz|>2nT or |∆By|>2nT. This last finding suggests that one should consider possible interplay effects between the simultaneous pressure and IMF changes in many situations.

  12. 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.

  13. 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.

  14. 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

  15. Measurement of temperature and pressure on the surface of a blunt cone using FBG sensor in hypersonic wind tunnel

    Science.gov (United States)

    Prasad, A. S. Guru; Sharath, U.; Nagarjun, V.; Hegde, G. M.; Asokan, S.

    2013-09-01

    Measurement of temperature and pressure exerted on the leeward surface of a blunt cone specimen has been demonstrated in the present work in a hypersonic wind tunnel using fiber Bragg grating (FBG) sensors. The experiments were conducted on a 30° apex-angle blunt cone with 51 mm base diameter at wind flow speeds of Mach 6.5 and 8.35 in a 300 mm hypersonic wind tunnel of Indian Institute of Science, Bangalore. A special pressure insensitive temperature sensor probe along with the conventional bare FBG sensors was used for explicit temperature and aerodynamic pressure measurement respectively on the leeward surface of the specimen. computational fluid dynamics (CFD) simulation of the flow field around the blunt cone specimen has also been carried out to obtain the temperature and pressure at conditions analogous to experiments. The results obtained from FBG sensors and the CFD simulations are found to be in good agreement with each other.

  16. Measurement of temperature and pressure on the surface of a blunt cone using FBG sensor in hypersonic wind tunnel

    International Nuclear Information System (INIS)

    Guru Prasad, A S; Sharath, U; Asokan, S; Nagarjun, V; Hegde, G M

    2013-01-01

    Measurement of temperature and pressure exerted on the leeward surface of a blunt cone specimen has been demonstrated in the present work in a hypersonic wind tunnel using fiber Bragg grating (FBG) sensors. The experiments were conducted on a 30° apex-angle blunt cone with 51 mm base diameter at wind flow speeds of Mach 6.5 and 8.35 in a 300 mm hypersonic wind tunnel of Indian Institute of Science, Bangalore. A special pressure insensitive temperature sensor probe along with the conventional bare FBG sensors was used for explicit temperature and aerodynamic pressure measurement respectively on the leeward surface of the specimen. computational fluid dynamics (CFD) simulation of the flow field around the blunt cone specimen has also been carried out to obtain the temperature and pressure at conditions analogous to experiments. The results obtained from FBG sensors and the CFD simulations are found to be in good agreement with each other. (paper)

  17. Reactive Power Compensation of a 24 MW Wind Farm using a 12-Pulse Voltage Source Converter

    DEFF Research Database (Denmark)

    Søbrink, K.H.; Pedersen, Jørgen Kaas; Pedersen, Knud Ole Helgesen

    1998-01-01

    Integration of large wind farms in distribution and transmission systems may have severe influence on the power quality at the connection point and may also influence the voltage controlling capability of the electrical system. The purpose of the described project has been to develop and investig...

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. On the excitation of ULF waves by solar wind pressure enhancements

    Directory of Open Access Journals (Sweden)

    P. T. I. Eriksson

    2006-11-01

    Full Text Available We study the onset and development of an ultra low frequency (ULF pulsation excited by a storm sudden commencement. On 30 August 2001, 14:10 UT, the Cluster spacecraft are located in the dayside magnetosphere and observe the excitation of a ULF pulsation by a threefold enhancement in the solar wind dynamic pressure. Two different harmonics are observed by Cluster, one at 6.8 mHz and another at 27 mHz. We observe a compressional wave and the development of a toroidal and poloidal standing wave mode. The toroidal mode is observed over a narrow range of L-shells whereas the poloidal mode is observed to have a much larger radial extent. By looking at the phase difference between the electric and magnetic fields we see that for the first two wave periods both the poloidal and toroidal mode are travelling waves and then suddenly change into standing waves. We estimate the azimuthal wave number for the 6.8 mHz to be m=10±3. For the 27 mHz wave, m seems to be several times larger and we discuss the implications of this. We conclude that the enhancement in solar wind pressure excites eigenmodes of the geomagnetic cavity/waveguide that propagate tailward and that these eigenmodes in turn couple to toroidal and poloidal mode waves. Thus our observations give firm support to the magnetospheric waveguide theory.

  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. Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

    Directory of Open Access Journals (Sweden)

    Linwood Jones

    2010-03-01

    Full Text Available Measurements of the near surface horizontal wind field in a hurricane with spatial resolution of order 1–10 km are possible using airborne microwave radiometer imagers. An assessment is made of the information content of the measured winds as a function of the spatial resolution of the imager. An existing algorithm is used which estimates the maximum surface air pressure depression in the hurricane eye from the maximum wind speed. High resolution numerical model wind fields from Hurricane Frances 2004 are convolved with various HIRAD antenna spatial filters to observe the impact of the antenna design on the central pressure depression in the eye that can be deduced from it.

  9. Aerodynamic noise characterization of a full-scale wind turbine through high-frequency surface pressure measurements

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Bak, Christian

    2015-01-01

    The aim of this work is to investigate and characterize the high-frequency surface pressure fluctuations on a full-scale wind turbine blade and in particular the influence of the atmospheric turbulence. As these fluctuations are highly correlated to the sources of both turbulent inflow noise...... and trailing edge noise, recognized to be the two main sources of noise from wind turbines, this work contributes to a more detailed insight into noise from wind turbines. The study comprises analysis and interpretation of measurement data that were acquired during an experimental campaign involving a 2 MW...... wind turbine with a 80 m diameter rotor as well as measurements of an airfoil section tested in a wind tunnel. The turbine was extensively equipped in order to monitor the local inflow onto the rotating blades. Further a section of the 38 m long blade was instrumented with 50 microphones flush...

  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. Electromagnetic Design and Losses Analysis of a High-Speed Permanent Magnet Synchronous Motor with Toroidal Windings for Pulsed Alternator

    Directory of Open Access Journals (Sweden)

    Yuan Wan

    2018-03-01

    Full Text Available The configuration of conventional high-speed Permanent Magnet Synchronous Motors (PMSMs is usually long and thin, with overlong axial end winding lengths, which is not suitable for those applications that place severe restrictions on the axial length, such as pulsed alternators. This paper first studied the key design aspects of a flat-structure high-speed PMSM. The toroidal-windings, low-conductivity material of the retaining sleeve, large airgap and segmentation of magnets were studied to reduce the axial length of the motor. The division of the stator and the employment of a non-magnetic outer stator were used to improve overall performance. Then the losses of the prototype were calculated and the factors having an influence on the losses were also investigated, after which, their effects on the total loss were evaluated. The total loss could be effectively reduced by the decrease of strand number of conductors and the division of stator, while only being slightly reduced by epoxy resin pole fillers. Metal-stack pole fillers have the same effect on the reduction of rotor loss as epoxy resin, while maintaining the good thermal-conductivity of metal. In addition, the influence of the carrier frequency of the inverter on the losses was analyzed, and it was found that high carrier frequency was helpful to reduce rotor losses. Finally, a small-scale prototype was manufactured and the experimental results were provided.

  13. Wind turbines and bat mortality: Doppler shift profiles and ultrasonic bat-like pulse reflection from moving turbine blades.

    Science.gov (United States)

    Long, Chloe V; Flint, James A; Lepper, Paul A

    2010-10-01

    Bat mortality resulting from actual or near-collision with operational wind turbine rotors is a phenomenon that is widespread but not well understood. Because bats rely on information contained in high-frequency echoes to determine the nature and movement of a target, it is important to consider how ultrasonic pulses similar to those used by bats for echolocation may be interacting with operational turbine rotor blades. By assessing the characteristics of reflected ultrasonic echoes, moving turbine blades operating under low wind speed conditions (<6 m s(-1)) were found to produce distinct Doppler shift profiles at different angles to the rotor. Frequency shifts of up to ±700-800 Hz were produced, which may not be perceptible by some bat species. Monte Carlo simulation of bat-like sampling by echolocation revealed that over 50 rotor echoes could be required by species such as Pipistrellus pipistrellus for accurate interpretation of blade movement, which may not be achieved in the bat's approach time-window. In summary, it was found that echoes returned from moving blades had features which could render them attractive to bats or which might make it difficult for the bat to accurately detect and locate blades in sufficient time to avoid a collision.

  14. Experiences with a high-blockage model tested in the NASA Ames 12-foot pressure wind tunnel

    Science.gov (United States)

    Coder, D. W.

    1984-01-01

    Representation of the flow around full-scale ships was sought in the subsonic wind tunnels in order to a Hain Reynolds numbers as high as possible. As part of the quest to attain the largest possible Reynolds number, large models with high blockage are used which result in significant wall interference effects. Some experiences with such a high blockage model tested in the NASA Ames 12-foot pressure wind tunnel are summarized. The main results of the experiment relating to wind tunnel wall interference effects are also presented.

  15. 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.

  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. 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.

  18. 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

  19. 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.

  20. 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.

  1. Miniaturized compact water-cooled pitot-pressure probe for flow-field surveys in hypersonic wind tunnels

    Science.gov (United States)

    Ashby, George C.

    1988-01-01

    An experimental investigation of the design of pitot probes for flowfield surveys in hypersonic wind tunnels is reported. The results show that a pitot-pressure probe can be miniaturized for minimum interference effects by locating the transducer in the probe support body and water-cooling it so that the pressure-settling time and transducer temperature are compatible with hypersonic tunnel operation and flow conditions. Flowfield surveys around a two-to-one elliptical cone model in a 20-inch Mach 6 wind tunnel using such a probe show that probe interference effects are essentially eliminated.

  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. 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.

  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. Experimental constraints on pulsed and steady state models of the solar wind near the Sun

    International Nuclear Information System (INIS)

    Feldman, W.C.; Habbal, S.R.; Hoogeveen, G.; Wang, Y.

    1997-01-01

    Ulysses observations of the high-latitude solar wind were combined with Spartan 201 observations of the corona to investigate the nature and extent of uncertainties in our knowledge of solar wind structure near the Sun. In addition to uncertainties stemming from the propagation of errors in density profiles inferred from coronagraph observations [see, e.g., Lallement et al., 1986], an assessment of the consequences of choosing different analysis assumptions reveals very large, fundamental uncertainties in our knowledge of even the basics of coronal structure near the Sun. In the spirit of demonstrating the nature and extent of these uncertainties we develop just one of a generic class of explicitly time-dependent and filamentary models of the corona that is consistent with the Ulysses and Spartan 201 data. This model provides a natural explanation for the radial profiles of both the axial ratios and apparent radial speeds of density irregularities measured at radial distances less than 10R S using the interplanetary scintillation technique. copyright 1997 American Geophysical Union

  7. Micro-pulse upconversion Doppler lidar for wind and visibility detection in the atmospheric boundary layer.

    Science.gov (United States)

    Xia, Haiyun; Shangguan, Mingjia; Wang, Chong; Shentu, Guoliang; Qiu, Jiawei; Zhang, Qiang; Dou, Xiankang; Pan, Jianwei

    2016-11-15

    For the first time, to the best of our knowledge, a compact, eye-safe, and versatile direct detection Doppler lidar is developed using an upconversion single-photon detection method at 1.5 μm. An all-fiber and polarization maintaining architecture is realized to guarantee the high optical coupling efficiency and the robust stability. Using integrated-optic components, the conservation of etendue of the optical receiver is achieved by manufacturing a fiber-coupled periodically poled lithium niobate waveguide and an all-fiber Fabry-Perot interferometer (FPI). The double-edge technique is implemented by using a convert single-channel FPI and a single upconversion detector, incorporating a time-division multiplexing method. The backscatter photons at 1548.1 nm are converted into 863 nm via mixing with a pump laser at 1950 nm. The relative error of the system is less than 0.1% over nine weeks. In experiments, atmospheric wind and visibility over 48 h are detected in the boundary layer. The lidar shows good agreement with the ultrasonic wind sensor, with a standard deviation of 1.04 m/s in speed and 12.3° in direction.

  8. The origin of stellar winds: Subatmospheric nonthermal storage modes versus radiation pressure

    International Nuclear Information System (INIS)

    Cannon, C.J.; Thomas, R.N.

    1977-01-01

    Most current models of matter-flux in hot stars place its origin in radiation pressure, and then model the flow explicitly to produce no chromosphere-corona. Our model of the stellar atmosphere as a transition zone between stellar interior and interstellar medium places the origin of matter-flux, chromosphere-corona, and spectral ''emission classes'' in subatmospheric nonthermal kinetic energy storage, equally for all stars, hot or cold. Current observations of both hot and cold stars suggest chromospheres to be a universal phenomenon, correlated with matter-fluxes, and enhanced in ''emission-class'' stars. To clarify the difference between the two kinds of models above, we reformulate the wind-tunnel analogy to stellar winds, suggesting that stars satisfy and ''imperfect,'' such model;i.e., transsonic shocks occur before the throat, corresponding to an imposed outward velocity in the storage section, or subatmosphere. We then investigate the stability of an arbitrary stellar atmosphere, hot or cold, to suggest a cause for such an outward subatmospheric velocity

  9. 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

  10. 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

  11. 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.

  12. 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...

  13. 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

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

    Directory of Open Access Journals (Sweden)

    T. R. Sun

    2012-08-01

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

  15. 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.

  16. 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.

  17. 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

  18. Radiation pressure in galactic disks: stability, turbulence, and winds in the single-scattering limit

    Science.gov (United States)

    Wibking, Benjamin D.; Thompson, Todd A.; Krumholz, Mark R.

    2018-04-01

    The radiation force on dust grains may be dynamically important in driving turbulence and outflows in rapidly star-forming galaxies. Recent studies focus on the highly optically-thick limit relevant to the densest ultra-luminous galaxies and super star clusters, where reprocessed infrared photons provide the dominant source of electromagnetic momentum. However, even among starburst galaxies, the great majority instead lie in the so-called "single-scattering" limit, where the system is optically-thick to the incident starlight, but optically-thin to the re-radiated infrared. In this paper we present a stability analysis and multidimensional radiation-hydrodynamic simulations exploring the stability and dynamics of isothermal dusty gas columns in this regime. We describe our algorithm for full angle-dependent radiation transport based on the discontinuous Galerkin finite element method. For a range of near-Eddington fluxes, we show that the medium is unstable, producing convective-like motions in a turbulent atmosphere with a scale height significantly inflated compared to the gas pressure scale height and mass-weighted turbulent energy densities of ˜0.01 - 0.1 of the midplane radiation energy density, corresponding to mass-weighted velocity dispersions of Mach number ˜0.5 - 2. Extrapolation of our results to optical depths of 103 implies maximum turbulent Mach numbers of ˜20. Comparing our results to galaxy-averaged observations, and subject to the approximations of our calculations, we find that radiation pressure does not contribute significantly to the effective supersonic pressure support in star-forming disks, which in general are substantially sub-Eddington. We further examine the time-averaged vertical density profiles in dynamical equilibrium and comment on implications for radiation-pressure-driven galactic winds.

  19. 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

  20. 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.

  1. 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.)

  2. 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.

  3. 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)

  4. Pressure Balance at Mars and Solar Wind Interaction with the Martian Atmosphere

    Science.gov (United States)

    Krymskii, A. M.; Ness, N. F.; Crider, D. H.; Breus, T. K.; Acuna, M. H.; Hinson, D.

    2003-01-01

    The strongest crustal fields are located in certain regions in the Southern hemisphere. In the Northern hemisphere, the crustal fields are rather weak and usually do not prevent direct interaction between the SW and the Martian ionosphere/atmosphere. Exceptions occur in the isolated mini-magnetospheres formed by the crustal anomalies. Electron density profiles of the ionosphere of Mars derived from radio occultation data obtained by the Radio Science Mars Global Surveyor (MGS) experiment have been compared with the crustal magnetic fields measured by the MGS Magnetometer/Electron Reflectometer (MAG/ER) experiment. A study of 523 electron density profiles obtained at latitudes from +67 deg. to +77 deg. has been conducted. The effective scale-height of the electron density for two altitude ranges, 145-165 km and 165-185 km, and the effective scale-height of the neutral atmosphere density in the vicinity of the ionization peak have been derived for each of the profiles studied. For the regions outside of the potential mini-magnetospheres, the thermal pressure of the ionospheric plasma for the altitude range 145-185 km has been estimated. In the high latitude ionosphere at Mars, the total pressure at altitudes 160 and 180 km has been mapped. The solar wind interaction with the ionosphere of Mars and origin of the sharp drop of the electron density at the altitudes 200-210 km will be discussed.

  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. 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...

  8. 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.

  9. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  10. A two-level voltage source inverter with differentially sinusoidal pulse width modulation used in the interconnection system of a wind turbine generator

    Directory of Open Access Journals (Sweden)

    Alexandros C. Charalampidis

    2014-10-01

    Full Text Available This study analyses an interconnection system based on differentially sinusoidal pulse width modulation, used for the interconnection to the grid of a variable speed wind turbine. The modulation technique used provides specific advantages in comparison with the commonly used sinusoidal pulse width modulation (SPWM technique, such as lower DC bus voltage requirements, smaller switching losses for the same switching frequency as well as less higher harmonic content in the voltage waveforms produced. The respective control system is also described in detail. Thus this study provides a guide enabling the design of any interconnection system based on this modulation technique.

  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. Simulation of Time-Varying Spatially Uniform Pressure and Near-Surface Wind Flows on Building Components and Cladding

    Directory of Open Access Journals (Sweden)

    Seraphy Y. Shen

    2017-05-01

    Full Text Available This paper describes a new full-scale (FS testing apparatus for conducting performance evaluations of FS building envelope systems. The simulator can generate spatially uniform, time-varying pressure conditions associated with Saffir–Simpson Hurricane Wind Scale Category 5 winds while compensating for large air leakage through the specimen and also operate a high-speed wind tunnel, both with dynamic control. This paper presents system details, operating characteristics, and an early case study on the performance of large sectional door systems under wind pressure loading. Failure mechanisms are discussed, and finite element modeling is validated for two specimens. It demonstrates successful dynamic load control for large component and cladding systems, as well as simulation of flows near the building surface. These capabilities serve to complement other FS wind tunnel facilities by offering tools to generate ultimate load conditions on portions of the building. Further, the paper successfully demonstrates the utility of combining physical testing and computational analysis as a matter of routine, which underscores the potential of evolving FS testing to encompass cyber–physical approaches.

  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. Comparison of ionospheric convection and the transpolar potential before and after solar wind dynamic pressure fronts: implications for magnetospheric reconnection

    Science.gov (United States)

    Boudouridis, A.; Zesta, E.; Lyons, L. R.; Kim, H.-J.; Lummerzheim, D.; Wiltberger, M.; Weygand, J. M.; Ruohoniemi, J. M.; Ridley, A. J.

    2012-04-01

    The solar wind dynamic pressure, both through its steady state value and through its variations, plays an important role in the determination of the state of the terrestrial magnetosphere and ionosphere, its effects being only secondary to those of the Interplanetary Magnetic Field (IMF). Recent studies have demonstrated the significant effect solar wind dynamic pressure enhancements have on ionospheric convection and the transpolar potential. Further studies have shown a strong response of the polar cap boundary and thus the open flux content of the magnetosphere. These studies clearly illustrate the strong coupling of solar wind dynamic pressure fronts to the terrestrial magnetosphere-ionosphere system. We present statistical studies of the response of Super Dual Auroral Radar Network (SuperDARN) flows, and Assimilative Mapping of Ionospheric Electrodynamics (AMIE) transpolar potentials to sudden enhancements in solar wind dynamic pressure. The SuperDARN results show that the convection is enhanced within both the dayside and nightside ionosphere. The dayside response is more clear and immediate, while the response on the nightside is slower and more evident for low IMF By values. AMIE results show that the overall convection, represented by the transpolar potential, has a strong response immediately after an increase in pressure, with magnitude and duration modulated by the background IMF Bz conditions. We compare the location of the SuperDARN convection enhancements with the location and motion of the polar cap boundary, as determined by POLAR Ultra-Violet Imager (UVI) images and runs of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic model for specific events. We find that the boundary exhibits a poleward motion after the increase in dynamic pressure. The enhanced ionospheric flows and the poleward motion of the boundary on the nightside are both signatures of enhanced tail reconnection, a conclusion that is reinforced by the observation of the

  16. Comprehensive wind correction for a Rayleigh Doppler lidar from atmospheric temperature and pressure influences and Mie contamination

    International Nuclear Information System (INIS)

    Shangguan Ming-Jia; Xia Hai-Yun; Dou Xian-Kang; Wang Chong; Qiu Jia-Wei; Zhang Yun-Peng; Shu Zhi-Feng; Xue Xiang-Hui

    2015-01-01

    A correction considering the effects of atmospheric temperature, pressure, and Mie contamination must be performed for wind retrieval from a Rayleigh Doppler lidar (RDL), since the so-called Rayleigh response is directly related to the convolution of the optical transmission of the frequency discriminator and the Rayleigh–Brillouin spectrum of the molecular backscattering. Thus, real-time and on-site profiles of atmospheric pressure, temperature, and aerosols should be provided as inputs to the wind retrieval. Firstly, temperature profiles under 35 km and above the altitude are retrieved, respectively, from a high spectral resolution lidar (HSRL) and a Rayleigh integration lidar (RIL) incorporating to the RDL. Secondly, the pressure profile is taken from the European Center for Medium range Weather Forecast (ECMWF) analysis, while radiosonde data are not available. Thirdly, the Klett–Fernald algorithms are adopted to estimate the Mie and Rayleigh components in the atmospheric backscattering. After that, the backscattering ratio is finally determined in a nonlinear fitting of the transmission of the atmospheric backscattering through the Fabry–Perot interferometer (FPI) to a proposed model. In the validation experiments, wind profiles from the lidar show good agreement with the radiosonde in the overlapping altitude. Finally, a continuous wind observation shows the stability of the correction scheme. (paper)

  17. Using Atmospheric Pressure Tendency to Optimise Battery Charging in Off-Grid Hybrid Wind-Diesel Systems for Telecoms

    Directory of Open Access Journals (Sweden)

    Stephen Daniels

    2013-06-01

    Full Text Available Off grid telecom base stations in developing nations are powered by diesel generators. They are typically oversized and run at a fraction of their rated load for most of their operating lifetime. Running generators at partial load is inefficient and, over time, physically damages the engine. A hybrid configuration uses a battery bank, which powers the telecoms’ load for a portion of the time. The generator only operates when the battery bank needs to be charged. Adding a wind turbine further reduces the generator run hours and saves fuel. The generator is oblivious to the current wind conditions, which leads to simultaneous generator-wind power production. As the batteries become charged by the generator, the wind turbine controller is forced to dump surplus power as heat through a resistive load. This paper details how the relationship between barometric pressure and wind speed can be used to add intelligence to the battery charger. A Simulink model of the system is developed to test the different battery charging configurations. This paper demonstrates that if the battery charger is aware of upcoming wind conditions, it will provide modest fuel savings and reduce generator run hours in small-scale hybrid energy systems.

  18. 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.

  19. Single-sided natural ventilation driven by wind pressure and temperature difference

    DEFF Research Database (Denmark)

    Larsen, Tine Steen; Heiselberg, Per

    2008-01-01

    -scale wind tunnel experiments have been made with the aim of making a new expression for calculation of the airflow rate in single-sided natural ventilation. During the wind tunnel experiments it was found that the dominating driving force differs between wind speed and temperature difference depending......Even though opening a window for ventilation of a room seems very simple, the flow that occurs in this situation is rather complicated. The amount of air going through the window opening will depend on the wind speed near the building, the temperatures inside and outside the room, the wind...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Features of energetic particle radial profiles inferred from geosynchronous responses to solar wind dynamic pressure enhancements

    Directory of Open Access Journals (Sweden)

    Y. Shi

    2009-02-01

    Full Text Available Determination of the radial profile of phase space density of relativistic electrons at constant adiabatic invariants is crucial for identifying the source for them within the outer radiation belt. The commonly used method is to convert flux observed at fixed energy to phase space density at constant first, second and third adiabatic invariants, which requires an empirical global magnetic field model and thus might produce some uncertainties in the final results. From a different perspective, in this paper we indirectly infer the shape of the radial profile of phase space density of relativistic electrons near the geosynchronous region by statistically examining the geosynchronous energetic flux response to 128 solar wind dynamic pressure enhancements during the years 2000 to 2003. We thus avoid the disadvantage of using empirical magnetic field models. Our results show that the flux response is species and energy dependent. For protons and low-energy electrons, the primary response to magnetospheric compression is an increase in flux at geosynchronous orbit. For relativistic electrons, the dominant response is a decrease in flux, which implies that the phase space density decreases toward increasing radial distance at geosynchronous orbit and leads to a local peak inside of geosynchronous orbit. The flux response of protons and non-relativistic electrons could result from a phase density that increases toward increasing radial distance, but this cannot be determined for sure due to the particle energization associated with pressure enhancements. Our results for relativistic electrons are consistent with previous results obtained using magnetic field models, thus providing additional confirmation that these results are correct and indicating that they are not the result of errors in their selected magnetic field model.

  5. 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.

  6. 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....

  7. Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

    Directory of Open Access Journals (Sweden)

    Insub Choi

    2015-03-01

    Full Text Available A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

  8. Electric wind produced by a surface dielectric barrier discharge operating in air at different pressures: aeronautical control insights

    International Nuclear Information System (INIS)

    Benard, N; Balcon, N; Moreau, E

    2008-01-01

    The effects of the ambient air pressure level on the electric wind produced by a single dielectric barrier discharge (DBD) have been investigated by Pitot velocity measurements. Pressures from 1 down to 0.2 atm were tested with a 32 kV p-p 1 kHz excitation. This preliminary study confirms the effectiveness of surface DBD at low pressure. Indeed, the induced velocity is strongly dependent on the ambient air pressure level. Quite surprisingly the produced airflow presents a local maximum at 0.6 atm. The measured velocities at 1 atm and 0.2 atm are 2.5 m s -1 and 3 m s -1 , respectively while 3.5 m s -1 is reached at 0.6 atm. The position of the maximal velocity always coincides with the plasma extension. Mass flow rate calculations indicate that the DBD is effective in real flight pressure conditions. (fast track communication)

  9. Study of dust re-suspension at low pressure in a dedicated wind-tunnel

    Science.gov (United States)

    Rondeau, Anthony; Sabroux, Jean-Christophe; Chassefière, Eric

    2015-04-01

    The atmosphere of several telluric planets or satellites are dusty. Such is the case of Earth, Venus, Mars and Titan, each bearing different aeolian processes linked principally to the kinematic viscosity of the near-surface atmosphere. Studies of the Martian atmosphere are particularly relevant for the understanding of the dust re-suspension phenomena at low pressure (7 mbar). It turns out that operation of fusion reactors of the tokamak design produces significant amount of dust through the erosion of plasma-facing components. Such dust is a key issue, both regarding the performance and the safety of a fusion reactor such as ITER, under construction in Cadarache, France. Indeed, to evaluate the explosion risk in the ITER fusion reactor, it is essential to quantify the re-suspended dust fraction as a function of the dust inventory that can be potentially mobilized during a loss of vacuum accident (LOVA), with air or water vapour ingress. A complete accident sequence will encompass dust re-suspension from near-vacuum up to atmospheric pressure. Here, we present experimental results of particles re-suspension fractions measured at 1000, 600 and 300 mbar in the IRSN BISE (BlowIng facility for airborne releaSE) wind tunnel. Both dust monolayer deposits and multilayer deposits were investigated. In order to obtain experimental re-suspension data of dust monolayer deposits, we used an optical microscope allowing to measure the re-suspended particles fraction by size intervals of 1 µm. The deposits were made up of tungsten particles on a tungsten surface (an ubiquitous plasma facing component) and alumina particles on a glass plate, as a surrogate. A comparison of the results with the so-called Rock'nRoll dust re-suspension model (Reeks and Hall, 2001) is presented and discussed. The multilayer deposits were made in a vacuum sedimentation chamber allowing to obtain uniform deposits in terms of thickness. The re-suspension experimental data of such deposits were obtained

  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. Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

    Science.gov (United States)

    Ozturk, D. S.; Zou, S.; Ridley, A. J.; Slavin, J. A.

    2018-04-01

    The global magnetosphere-ionosphere-thermosphere system is intrinsically coupled and susceptible to external drivers such as solar wind dynamic pressure enhancements. In order to understand the large-scale dynamic processes in the magnetosphere-ionosphere-thermosphere system due to the compression from the solar wind, the 17 March 2015 sudden commencement was studied in detail using global numerical models. This storm was one of the most geoeffective events of the solar cycle 24 with a minimum Dst of -222 nT. The Wind spacecraft recorded a 10-nPa increment in the solar wind dynamic pressure, while the interplanetary magnetic field BZ became further northward. The University of Michigan Block-Adaptive-Tree Solar wind Roe-type Upwind Scheme global magnetohydrodynamic code was utilized to study the generation and propagation of perturbations associated with the compression of the magnetosphere system. In addition, the high-resolution electric potential and auroral power output from the magnetohydrodynamic model was used to drive the global ionosphere-thermosphere model to investigate the ionosphere-thermosphere system response to pressure enhancement. During the compression, the electric potentials and convection patterns in the polar ionosphere were significantly altered when the preliminary impulse and main impulse field-aligned currents moved from dayside to nightside. As a result of enhanced frictional heating, plasma and neutral temperatures increased at the locations where the flow speeds were enhanced, whereas the electron density dropped at these locations. In particular, the region between the preliminary impulse and main impulse field-aligned currents experienced the most significant heating with 1000-K ion temperature increase and 20-K neutral temperature increase within 2 min. Comparison of the simulation results with the Poker Flat Incoherent Scatter Radar observations showed reasonable agreements despite underestimated magnitudes.

  12. Efficacy of spatial averaging of infrasonic pressure in varying wind speeds

    International Nuclear Information System (INIS)

    DeWolf, Scott; Walker, Kristoffer T.; Zumberge, Mark A.; Denis, Stephane

    2013-01-01

    Wind noise reduction (WNR) is important in the measurement of infra-sound. Spatial averaging theory led to the development of rosette pipe arrays. The efficacy of rosettes decreases with increasing wind speed and only provides a maximum of 20 dB WNR due to a maximum size limitation. An Optical Fiber Infra-sound Sensor (OFIS) reduces wind noise by instantaneously averaging infra-sound along the sensor's length. In this study two experiments quantify the WNR achieved by rosettes and OFISs of various sizes and configurations. Specifically, it is shown that the WNR for a circular OFIS 18 m in diameter is the same as a collocated 32-inlet pipe array of the same diameter. However, linear OFISs ranging in length from 30 to 270 m provide a WNR of up to 30 dB in winds up to 5 m/s. The measured WNR is a logarithmic function of the OFIS length and depends on the orientation of the OFIS with respect to wind direction. OFISs oriented parallel to the wind direction achieve 4 dB greater WNR than those oriented perpendicular to the wind. Analytical models for the rosette and OFIS are developed that predict the general observed relationships between wind noise reduction, frequency, and wind speed. (authors)

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. The Effects of Solar Wind Dynamic Pressure Changes on the Substorm Auroras and Energetic Electron Injections on 24 August 2005

    Science.gov (United States)

    Li, L. Y.; Wang, Z. Q.

    2018-01-01

    After the passage of an interplanetary (IP) shock at 06:13 UT on 24 August 2005, the enhancement (>6 nPa) of solar wind dynamic pressure and the southward turning of interplanetary magnetic field (IMF) cause the earthward movement of dayside magnetopause and the drift loss of energetic particles near geosynchronous orbit. The persistent electron drift loss makes the geosynchronous satellites cannot observe the substorm electron injection phenomenon during the two substorm expansion phases (06:57-07:39 UT) on that day. Behind the IP shock, the fluctuations ( 0.5-3 nPa) of solar wind dynamic pressure not only alter the dayside auroral brightness but also cause the entire auroral oval to swing in the day-night direction. However, there is no Pi2 pulsation in the nightside auroral oval during the substorm growth phase from 06:13 to 06:57 UT. During the subsequent two substorm expansion phases, the substorm expansion activities cause the nightside aurora oval brightening from substorm onset site to higher latitudes, and meanwhile, the enhancement (decline) of solar wind dynamic pressure makes the nightside auroral oval move toward the magnetic equator (the magnetic pole). These observations demonstrate that solar wind dynamic pressure changes and substorm expansion activities can jointly control the luminosity and location of the nightside auroral oval when the internal and external disturbances occur simultaneously. During the impact of a strong IP shock, the earthward movement of dayside magnetopause probably causes the disappearance of the substorm electron injections near geosynchronous orbit.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. Wind-tunnel investigations of pressure distribution over high-rise buildings

    CSIR Research Space (South Africa)

    Cwik, M

    2013-09-01

    Full Text Available of evaluating wind loads of high-rise structures. The second part provides a description of the research, conducted at the wind-tunnel of the Council for Scientific and Industrial Research, in Pretoria, South Africa. The aim of this research was to determine...

  3. 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.

  4. 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)

  5. Advances in High Energy Solid-State Pulsed 2-Micron Lidar Development for Ground and Airborne Wind, Water Vapor and CO2 Measurements

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Kavaya, Michael J.; Remus, Ruben

    2015-01-01

    NASA Langley Research Center has a long history of developing 2-micron lasers. From fundamental spectroscopy research, theoretical prediction of new materials, laser demonstration and engineering of lidar systems, it has been a very successful program spanning around two decades. Successful development of 2-micron lasers has led to development of a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement with an unprecedented laser pulse energy of 250 millijoules in a rugged package. This high pulse energy is produced by a Ho:Tm:LuLiF laser with an optical amplifier. While the lidar is meant for use as an airborne instrument, ground-based tests were carried out to characterize performance of the lidar. Atmospheric measurements will be presented, showing the lidar's capability for wind measurement in the atmospheric boundary layer and free troposphere. Lidar wind measurements are compared to a balloon sonde, showing good agreement between the two sensors. Similar architecture has been used to develop a high energy, Ho:Tm:YLF double-pulsed 2-micron Integrated Differential Absorption Lidar (IPDA) instrument based on direct detection technique that provides atmospheric column CO2 measurements. This instrument has been successfully used to measure atmospheric CO2 column density initially from a ground mobile lidar trailer, and then it was integrated on B-200 plane and 20 hours of flight measurement were made from an altitude ranging 1500 meters to 8000 meters. These measurements were compared to in-situ measurements and National Oceanic and Atmospheric Administration (NOAA) airborne flask measurement to derive the dry mixing ratio of the column CO2 by reflecting the signal by various reflecting surfaces such as land, vegetation, ocean surface, snow and sand. The lidar measurements when compared showed a very agreement with in-situ and airborne flask measurement. NASA Langley Research Center is currently developing a

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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....

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. Inverse measurement of wall pressure field in flexible-wall wind tunnels using global wall deformation data

    Science.gov (United States)

    Brown, Kenneth; Brown, Julian; Patil, Mayuresh; Devenport, William

    2018-02-01

    The Kevlar-wall anechoic wind tunnel offers great value to the aeroacoustics research community, affording the capability to make simultaneous aeroacoustic and aerodynamic measurements. While the aeroacoustic potential of the Kevlar-wall test section is already being leveraged, the aerodynamic capability of these test sections is still to be fully realized. The flexibility of the Kevlar walls suggests the possibility that the internal test section flow may be characterized by precisely measuring small deflections of the flexible walls. Treating the Kevlar fabric walls as tensioned membranes with known pre-tension and material properties, an inverse stress problem arises where the pressure distribution over the wall is sought as a function of the measured wall deflection. Experimental wall deformations produced by the wind loading of an airfoil model are measured using digital image correlation and subsequently projected onto polynomial basis functions which have been formulated to mitigate the impact of measurement noise based on a finite-element study. Inserting analytic derivatives of the basis functions into the equilibrium relations for a membrane, full-field pressure distributions across the Kevlar walls are computed. These inversely calculated pressures, after being validated against an independent measurement technique, can then be integrated along the length of the test section to give the sectional lift of the airfoil. Notably, these first-time results are achieved with a non-contact technique and in an anechoic environment.

  1. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Verscharen, Daniel [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Wicks, Robert T., E-mail: daniel.verscharen@unh.edu, E-mail: christopher.chen@imperial.ac.uk, E-mail: r.wicks@ucl.ac.uk [Mullard Space Science Laboratory, University College London, London WC1E 6BT (United Kingdom)

    2017-05-10

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  2. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    International Nuclear Information System (INIS)

    Verscharen, Daniel; Chen, Christopher H. K.; Wicks, Robert T.

    2017-01-01

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  3. 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...

  4. 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)

  5. 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.

  6. 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.

  7. 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

  8. Dynamic lift measurements on a FX79W151A airfoil via pressure distribution on the wind tunnel walls

    Energy Technology Data Exchange (ETDEWEB)

    Wolken-Moehlmann, Gerrit [ForWind - Center for Wind Energy Research, University of Oldenburg (Germany); Knebel, Pascal [ForWind - Center for Wind Energy Research, University of Oldenburg (Germany); Barth, Stephan [ECN Wind Energy, Energy research Centre of the (Netherlands); Peinke, Joachim [ForWind - Center for Wind Energy Research, University of Oldenburg (Germany)

    2007-07-15

    We report on an experimental setup for measurements of dynamic stall for airfoils via the pressure distribution over wind tunnel walls. This measuring technique, hitherto used for lift measurements under static conditions, is also an adequate method for dynamic conditions until stall occurs. A step motor is used, allowing for sinusoidal as well as non-sinusoidal and stochastic pitching to simulate fast fluctuating flow conditions. Measurements with sinusoidal pitching and constant angular velocities were done and show dynamic stall characteristics. Under dynamic stall conditions, maximum lift coefficients were up to 80% higher than the maximum for static lift.

  9. Probing the properties of the pulsar wind via studying the dispersive effects in the pulses from the pulsar companion in a double neutron-star binary system

    Science.gov (United States)

    Yi, Shu-Xu; Cheng, K.-S.

    2017-12-01

    The velocity and density distribution of e± in the pulsar wind are crucial distinction among magnetosphere models, and contain key parameters determining the high-energy emission of pulsar binaries. In this work, a direct method is proposed, which might probe the properties of the wind from one pulsar in a double-pulsar binary. When the radio signals from the first-formed pulsar travel through the relativistic e± flow in the pulsar wind from the younger companion, the components of different radio frequencies will be dispersed. It will introduce an additional frequency-dependent time-of-arrival delay of pulses, which is function of the orbital phase. In this paper, we formulate the above-mentioned dispersive delay with the properties of the pulsar wind. As examples, we apply the formula to the double-pulsar system PSR J0737-3039A/B and the pulsar-neutron star binary PSR B1913+16. For PSR J0737-3039A/B, the time delay in 300 MHz is ≲ 10 μ s-1 near the superior conjunction, under the optimal pulsar wind parameters, which is approximately half of the current timing accuracy. For PSR B1913+16, with the assumption that the neutron-star companion has a typical spin-down luminosity of 1033 erg s-1, the time delay is as large as 10 - 20 μ s-1 in 300 MHz. The best timing precision of this pulsar is ∼ 5 μ s-1 in 1400 MHz. Therefore, it is possible that we can find this signal in archival data. Otherwise, we can set an upper limit on the spin-down luminosity. Similar analysis can be applied to other 11 known pulsar-neutron star binaries.

  10. 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.

  11. Pressure integration technique for predicting wind-induced response in high-rise buildings

    Directory of Open Access Journals (Sweden)

    Aly Mousaad Aly

    2013-12-01

    Full Text Available This paper presents a procedure for response prediction in high-rise buildings under wind loads. The procedure is illustrated in an application example of a tall building exposed to both cross-wind and along-wind loads. The responses of the building in the lateral directions combined with torsion are estimated simultaneously. Results show good agreement with recent design standards; however, the proposed procedure has the advantages of accounting for complex mode shapes, non-uniform mass distribution, and interference effects from the surrounding. In addition, the technique allows for the contribution of higher modes. For accurate estimation of the acceleration response, it is important to consider not only the first two lateral vibrational modes, but also higher modes. Ignoring the contribution of higher modes may lead to underestimation of the acceleration response; on the other hand, it could result in overestimation of the displacement response. Furthermore, the procedure presented in this study can help decision makers, involved in a tall building design/retrofit to choose among innovative solutions like aerodynamic mitigation, structural member size adjustment, damping enhancement, and/or materials change, with an objective to improve the resiliency and the serviceability under extreme wind actions.

  12. 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.

  13. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...... pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations...... induced by wind turbulence, vortex shedding, flutter and galloping. The book gives a comprehensive treatment of wind effects on structures and it will be useful for consulting engineers designing wind-sensitive structures. It will also be valuable for students of civil engineering as textbook...

  14. Pressure-Sensitive Paint Measurements on the NASA Common Research Model in the NASA 11-ft Transonic Wind Tunnel

    Science.gov (United States)

    Bell, James H.

    2011-01-01

    The luminescence lifetime technique was used to make pressure-sensitive paint (PSP) measurements on a 2.7% Common Research Model in the NASA Ames 11ft Transonic Wind Tunnel. PSP data were obtained on the upper and lower surfaces of the wing and horizontal tail, as well as one side of the fuselage. Data were taken for several model attitudes of interest at Mach numbers between 0.70 and 0.87. Image data were mapped onto a three-dimensional surface grid suitable both for comparison with CFD and for integration of pressures to determine loads. Luminescence lifetime measurements were made using strobed LED (light-emitting diode) lamps to illuminate the PSP and fast-framing interline transfer cameras to acquire the PSP emission.

  15. 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.

  16. 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.

  17. 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....

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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

  3. 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.

  4. Structure of Mercury's magnetosphere for different pressure of the solar wind: Three dimensional hybrid simulations

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Pavel; Hellinger, Petr; Schriver, D.

    2007-01-01

    Roč. 34, č. 5 (2007), L05104/1-L05104/5 ISSN 0094-8276 R&D Projects: GA ČR GA205/05/1011 Institutional research plan: CEZ:AV0Z30420517 Keywords : Global simulations * Mercury's magnetosphere * solar wind * hybrid simulations * ion drift driven rings Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.744, year: 2007

  5. Inspection and Reconstruction of Metal-Roof Deformation under Wind Pressure Based on Bend Sensors

    OpenAIRE

    Yang, Liman; Cui, Langfu; Li, Yunhua; An, Chao

    2017-01-01

    Metal roof sheathings are widely employed in large-span buildings because of their light weight, high strength and corrosion resistance. However, their severe working environment may lead to deformation, leakage and wind-lift, etc. Thus, predicting these damages in advance and taking maintenance measures accordingly has become important to avoid economic losses and personal injuries. Conventionally, the health monitoring of metal roofs mainly relies on manual inspection, which unavoidably com...

  6. 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.

  7. Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

    Science.gov (United States)

    Makarieva, A. M.; Gorshkov, V. G.; Sheil, D.; Nobre, A. D.; Li, B.-L.

    2013-01-01

    Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power - this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

  8. 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.

  9. 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.

  10. Influence of placement and height of high-rise buildings on wind pressure distribution and natural ventilation of low- and medium-rise buildings

    Czech Academy of Sciences Publication Activity Database

    Kuznetsov, Sergeii; Butova, A.; Pospíšil, Stanislav

    2016-01-01

    Roč. 15, 3/4 (2016), s. 253-266 ISSN 1473-3315 R&D Projects: GA ČR(CZ) GA14-12892S; GA MŠk(CZ) LO1219 Keywords : natural ventilation * high-rise building s * low- and medium-rise building s * wind pressure coefficient * wind tunnel tests Subject RIV: JM - Building Engineering Impact factor: 0.391, year: 2016 http://www.tandfonline.com/doi/full/10.1080/14733315.2016.1214396

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. Effects of Mie tip-vane on pressure distribution of rotor blade and power augmentation of horizontal axis wind turbine; Yokutan shoyoku Mie ben ni yoru suiheijiku fusha yokumenjo no atsuryoku bunpu no kaizen to seino kojo tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Y.; Maeda, T.; Kamada, Y. [Mie Univ., Mie (Japan); Seto, H. [Mitsubishi Motors Corp., Tokyo (Japan)

    2000-04-01

    By recent developments of exclusive rotor blade, the efficiency of wind turbine is improved substantially. By measuring pressure on rotor blades of horizontal axis wind turbines rotating in wind tunnels, this report clarified relation between improvement of pressure distribution on main rotor blades by Mie vane and upgrade of wind turbine performance. The results under mentioned have been got by measuring pressure distribution on rotor blades, visualization by tuft, and measuring resistance of Mie vane. (1) The difference of pressure between suction surface and pressure surface on the end of rotor blade increase, and output power of wind turbine improves. (2) Vortex of blade end is inhibited by Mie vane. (3) The reason of reduction on wind turbine performance with Mie vane in aria of high rotating speed ratio is the increase of Mie vane flow resistance.(NEDO)

  1. 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.

  2. [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.

  3. Low frequency geomagnetic field fluctuations at low latitude during the passage of a higher pressure solar wind region

    Directory of Open Access Journals (Sweden)

    U. Villante

    1997-06-01

    Full Text Available The passage of a higher pressure solar wind region at the Earth's orbit marked the onset of low latitude (L=1.6 fluctuations in the frequency range (0.8–5.5 mHz for both the horizontal geomagnetic field components. Spectral peaks mostly occur at the same frequencies as the spectral enhancements which appeared in the long term analysis of experimental measurements from the same station and were tentatively interpreted in terms of ground signatures of global magnetospheric modes. A comparison with simultaneous observations discussed by previous investigations allows us to conclude that the same set of frequencies is enhanced in a wide portion of the Earth's magnetosphere.

  4. F-8 supercritical wing flight pressure, Boundary layer, and wake measurements and comparisons with wind tunnel data

    Science.gov (United States)

    Montoya, L. C.; Banner, R. D.

    1977-01-01

    Data for speeds from Mach 0.50 to Mach 0.99 are presented for configurations with and without fuselage area-rule additions, with and without leading-edge vortex generators, and with and without boundary-layer trips on the wing. The wing pressure coefficients are tabulated. Comparisons between the airplane and model data show that higher second velocity peaks occurred on the airplane wing than on the model wing. The differences were attributed to wind tunnel wall interference effects that caused too much rear camber to be designed into the wing. Optimum flow conditions on the outboard wing section occurred at Mach 0.98 at an angle of attack near 4 deg. The measured differences in section drag with and without boundary-layer trips on the wing suggested that a region of laminar flow existed on the outboard wing without trips.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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 ...

  10. 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

  11. 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

  12. Weather and climate needs for Lidar observations from space and concepts for their realization. [wind, temperature, moisture, and pressure data needs

    Science.gov (United States)

    Atlas, D.; Korb, C. L.

    1980-01-01

    The spectrum of weather and climate needs for Lidar observations from space is discussed with emphasis on the requirements for wind, temperature, moisture, and pressure data. It is shown that winds are required to realistically depict all atmospheric scales in the tropics and the smaller scales at higher latitudes, where both temperature and wind profiles are necessary. The need for means to estimate air-sea exchanges of sensible and latent heat also is noted. A concept for achieving this through a combination of Lidar cloud top heights and IR cloud top temperatures of cloud streets formed during cold air outbreaks over the warmer ocean is outlined. Recent theoretical feasibility studies concerning the profiling of temperatures, pressure, and humidity by differential absorption Lidar (DIAL) from space and expected accuracies are reviewed. An alternative approach to Doppler Lidar wind measurements also is presented. The concept involves the measurement of the displacement of the aerosol backscatter pattern, at constant heights, between two successive scans of the same area, one ahead of the spacecraft and the other behind it a few minutes later. Finally, an integrated space Lidar system capable of measuring temperature, pressure, humidity, and winds which combines the DIAL methods with the aerosol pattern displacement concept is described.

  13. 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

  14. Flight and full-scale wind-tunnel comparison of pressure distributions from an F-18 aircraft at high angles of attack. [Conducted in NASA Ames Research Center's 80 by 120 ft wind tunnel

    Science.gov (United States)

    Fisher, David F.; Lanser, Wendy R.

    1994-01-01

    Pressure distributions were obtained at nearly identical fuselage stations and wing chord butt lines in flight on the F-18 HARV at NASA Dryden Flight Research Center and in the NASA Ames Research Center's 80 by 120 ft wind tunnel on a full-scale F/A-18 aircraft. The static pressures were measured at the identical five stations on the forebody, three stations on the left and right leading-edge extensions, and three spanwise stations on the wing. Comparisons of the flight and wind-tunnel pressure distributions were made at alpha = 30 deg, 45 deg, and 60 deg/59 deg. In general, very good agreement was found. Minor differences were noted at the forebody at alpha = 45 deg and 60 deg in the magnitude of the vortex footprints and a Mach number effect was noted at the leading-edge extension at alpha = 30 deg. The inboard leading edge flap data from the wind tunnel at alpha = 59 deg showed a suction peak that did not appear in the flight data. This was the result of a vortex from the corner of the leading edge flap whose path was altered by the lack of an engine simulation in the wind tunnel.

  15. 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.

  16. 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.

  17. 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.)

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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)

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Development of solar wind shock models with tensor plasma pressure for data analysis. Final technical report, 1 Aug 1970--31 Dec 1975

    International Nuclear Information System (INIS)

    Abraham-shrauner, B.

    1975-01-01

    The development of solar wind shock models with tensor plasma pressure and the comparison of some of the shock models with the satellite data from Pioneer 6 through Pioneer 9 are reported. Theoretically, difficulties were found in non-turbulent fluid shock models for tensor pressure plasmas. For microscopic shock theories nonlinear growth caused by plasma instabilities was frequently not clearly demonstrated to lead to the formation of a shock. As a result no clear choice for a shock model for the bow shock or interplanetary tensor pressure shocks emerged

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Mapping near-surface air temperature, pressure, relative humidity and wind speed over Mainland China with high spatiotemporal resolution

    Science.gov (United States)

    Li, Tao; Zheng, Xiaogu; Dai, Yongjiu; Yang, Chi; Chen, Zhuoqi; Zhang, Shupeng; Wu, Guocan; Wang, Zhonglei; Huang, Chengcheng; Shen, Yan; Liao, Rongwei

    2014-09-01

    As part of a joint effort to construct an atmospheric forcing dataset for mainland China with high spatiotemporal resolution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km×1 km. The approach comprises two steps: (1) fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; (2) apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over mainland China. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. [Comfort of crew and passengers and atmospheric pressure, noise, wind speed in high-speed train of Shijiazhuang-Taiyuan passenger dedicated line].

    Science.gov (United States)

    Zhai, Yi-biao; Huo, Wei; Liu, Qiao-ying; Chen, Bao-shan; Zhang, Jin-long; Shi, Lei

    2012-11-01

    To explore the crew and passengers' comfort on the Shijiazhuang-Taiyuan passenger dedicated line and physical factors, such as air pressure, noise, wind speed. Comfort investigation of all the crew (n = 244) and passengers (n = 377) on the Shijiazhuang-Taiyuan passenger dedicated line at speed of 250 km/h and 200 km/h and the detection of the air pressure, noise and wind speed were performed in 2011. Significantly higher ratio of comfortable feeling, lower ratio of seriously discomfortable feeling were observed in crew and passengers at 200 km/h compared with those at 250 km/h (P noise in passengers at 200 km/h. No significant difference was observed in ear discomfort induced by air pressure and noise among crew, and the duration of disappearance of discomfortable feeling among passengers between 200 km/h and 250 km/h. The noise in carriages exceeded the related standard when the high-speed train passing through the tunnels. The individuals feel more comfortable at 200 km/h than 250 km/h in this line., which may be related with rapid variation of wind speed and noise when the train passes through the tunnels with high speed.

  3. 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

  4. Wind power plant

    Energy Technology Data Exchange (ETDEWEB)

    Caneghem, A.E. von

    1975-07-24

    The invention applies to a wind power plant in which the wind is used to drive windmills. The plant consists basically of a vertical tube with a lateral wind entrance opening with windmill on its lower end. On its upper end, the tube carries a nozzle-like top which increases the wind entering the tube by pressure decrease. The wind is thus made suitable for higher outputs. The invention is illustrated by constructional examples.

  5. 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.

  6. 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.

  7. 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

  8. Wing pressure distributions from subsonic tests of a high-wing transport model. [in the Langley 14- by 22-Foot Subsonic Wind Tunnel

    Science.gov (United States)

    Applin, Zachary T.; Gentry, Garl L., Jr.; Takallu, M. A.

    1995-01-01

    A wind tunnel investigation was conducted on a generic, high-wing transport model in the Langley 14- by 22-Foot Subsonic Tunnel. This report contains pressure data that document effects of various model configurations and free-stream conditions on wing pressure distributions. The untwisted wing incorporated a full-span, leading-edge Krueger flap and a part-span, double-slotted trailing-edge flap system. The trailing-edge flap was tested at four different deflection angles (20 deg, 30 deg, 40 deg, and 60 deg). Four wing configurations were tested: cruise, flaps only, Krueger flap only, and high lift (Krueger flap and flaps deployed). Tests were conducted at free-stream dynamic pressures of 20 psf to 60 psf with corresponding chord Reynolds numbers of 1.22 x 10(exp 6) to 2.11 x 10(exp 6) and Mach numbers of 0.12 to 0.20. The angles of attack presented range from 0 deg to 20 deg and were determined by wing configuration. The angle of sideslip ranged from minus 20 deg to 20 deg. In general, pressure distributions were relatively insensitive to free-stream speed with exceptions primarily at high angles of attack or high flap deflections. Increasing trailing-edge Krueger flap significantly reduced peak suction pressures and steep gradients on the wing at high angles of attack. Installation of the empennage had no effect on wing pressure distributions. Unpowered engine nacelles reduced suction pressures on the wing and the flaps.

  9. 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.

  10. High pressure gas laser technology for atmospheric remote sensing

    Science.gov (United States)

    Javan, A.

    1980-01-01

    The development of a fixed frequency chirp-free and highly stable intense pulsed laser made for Doppler wind velocity measurements with accurate ranging is described. Energy extraction from a high pressure CO2 laser at a tunable single mode frequency is also examined.

  11. 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)

  12. 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

  13. 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

  14. 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

  15. 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.

  16. Combining Unsteady Blade Pressure Measurements and a Free-Wake Vortex Model to Investigate the Cycle-to-Cycle Variations in Wind Turbine Aerodynamic Blade Loads in Yaw

    Directory of Open Access Journals (Sweden)

    Moutaz Elgammi

    2016-06-01

    Full Text Available Prediction of the unsteady aerodynamic flow phenomenon on wind turbines is challenging and still subject to considerable uncertainty. Under yawed rotor conditions, the wind turbine blades are subjected to unsteady flow conditions as a result of the blade advancing and retreating effect and the development of a skewed vortical wake created downstream of the rotor plane. Blade surface pressure measurements conducted on the NREL Phase VI rotor in yawed conditions have shown that dynamic stall causes the wind turbine blades to experience significant cycle-to-cycle variations in aerodynamic loading. These effects were observed even though the rotor was subjected to a fixed speed and a uniform and steady wind flow. This phenomenon is not normally predicted by existing dynamic stall models integrated in wind turbine design codes. This paper couples blade pressure measurements from the NREL Phase VI rotor to a free-wake vortex model to derive the angle of attack time series at the different blade sections over multiple rotor rotations and three different yaw angles. Through the adopted approach it was possible to investigate how the rotor self-induced aerodynamic load fluctuations influence the unsteady variations in the blade angles of attack and induced velocities. The hysteresis loops for the normal and tangential load coefficients plotted against the angle of attack were plotted over multiple rotor revolutions. Although cycle-to-cycle variations in the angles of attack at the different blade radial locations and azimuth positions are found to be relatively small, the corresponding variations in the normal and tangential load coefficients may be significant. Following a statistical analysis, it was concluded that the load coefficients follow a normal distribution at the majority of blade azimuth angles and radial locations. The results of this study provide further insight on how existing engineering models for dynamic stall may be improved through

  17. Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

    Science.gov (United States)

    Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2018-05-01

    Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

  18. Spots on electrodes and images of a gap during pulsed discharges in an inhomogeneous electric field at elevated pressures of air, nitrogen and argon

    International Nuclear Information System (INIS)

    Shao, Tao; Yang, Wenjin; Zhang, Cheng; Yan, Ping; Tarasenko, Victor F; Beloplotov, Dmitry V; Lomaev, Mikhail I; Sorokin, Dmitry A

    2014-01-01

    Pulsed discharge in a nonuniform electric field accompanied by the appearance of bright spots due to explosive electron emission on electrodes has been investigated. The experiments were carried out using three experimental setups, a voltage pulse duration at a matched load of 2 ns, 40 ns, and 130 ns, respectively. Data on the formation of electrode spots during diffuse discharges in tube-plate or needle-plate gap configurations filled with gases at elevated pressures (air, nitrogen and argon) were obtained. It was found that in the air and other gases, bright spots arise on the flat electrode, and on the negative polarity of the electrode with a small radius of curvature, during the direction change of the current through the gap and the increase of the voltage pulse duration. It was shown that at the positive polarity of the electrode with a small radius of curvature, bright spots on the flat electrode arise due to the participation of the dynamic displacement current in the gap conductance. (paper)

  19. DC-pulse atmospheric-pressure plasma jet and dielectric barrier discharge surface treatments on fluorine-doped tin oxide for perovskite solar cell application

    Science.gov (United States)

    Tsai, Jui-Hsuan; Cheng, I.-Chun; Hsu, Cheng-Che; Chen, Jian-Zhang

    2018-01-01

    Nitrogen DC-pulse atmospheric-pressure plasma jet (APPJ) and nitrogen dielectric barrier discharge (DBD) were applied to pre-treat fluorine-doped tin oxide (FTO) glass substrates for perovskite solar cells (PSCs). Nitrogen DC-pulse APPJ treatment (substrate temperature: ~400 °C) for 10 s can effectively increase the wettability, whereas nitrogen DBD treatment (maximum substrate temperature: ~140 °C) achieved limited improvement in wettability even with increased treatment time of 60 s. XPS results indicate that 10 s APPJ, 60 s DBD, and 15 min UV-ozone treatment of FTO glass substrates can decontaminate the surface. A PSC fabricated on APPJ-treated FTO showed the highest power conversion efficiency (PCE) of 14.90%; by contrast, a PSC with nitrogen DBD-treated FTO shows slightly lower PCE of 12.57% which was comparable to that of a PSC on FTO treated by a 15 min UV-ozone process. Both nitrogen DC-pulse APPJ and nitrogen DBD can decontaminate FTO substrates and can be applied for the substrate cleaning step of PSC.

  20. 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.

  1. Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, T.; Sano-Furukawa, A. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Komatsu, K. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Yamada, A. [University of Shiga Prefecture, Shiga 522-8533 (Japan); Inamura, Y.; Nakatani, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Seto, Y. [Graduate School of Science, Kobe University, Kobe 657-8501 (Japan); Nagai, T. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Utsumi, W. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Iitaka, T. [Computational Astrophysics Laboratory, RIKEN, Saitama 351-0198 (Japan); Kagi, H. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Katayama, Y. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Inoue, T. [Geodynamic Research Center, Ehime University, Matsuyama 790-8577 (Japan); Otomo, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Suzuya, K. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Kamiyama, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Arai, M. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

    2015-04-21

    PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (Δd/d~0.6%) and the accessible d-spacing range (0.2–8.4 Å) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.

  2. Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

    International Nuclear Information System (INIS)

    Hattori, T.; Sano-Furukawa, A.; Arima, H.; Komatsu, K.; Yamada, A.; Inamura, Y.; Nakatani, T.; Seto, Y.; Nagai, T.; Utsumi, W.; Iitaka, T.; Kagi, H.; Katayama, Y.; Inoue, T.; Otomo, T.; Suzuya, K.; Kamiyama, T.; Arai, M.; Yagi, T.

    2015-01-01

    PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (Δd/d~0.6%) and the accessible d-spacing range (0.2–8.4 Å) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions

  3. ImPressOne: A Pressure Display and Acquisition Program for the Low Speed Wind Tunnel at DSTO

    National Research Council Canada - National Science Library

    Blandford, Adam

    2005-01-01

    ... time as the test progresses. A software package called ImPressOne was developed for this purpose giving a graphical display of the pressure and the ability to acquire pressure sets and save the data to file...

  4. Pulsed water jet generated by pulse multiplication

    Czech Academy of Sciences Publication Activity Database

    Dvorský, R.; Sitek, Libor; Sochor, T.

    2016-01-01

    Roč. 23, č. 4 (2016), s. 959-967 ISSN 1330-3651 R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : high- pressure pulses * pulse intensifier * pulsed water jet * water hammer effect Subject RIV: JQ - Machines ; Tools Impact factor: 0.723, year: 2016 http://hrcak.srce.hr/163752?lang=en

  5. Pulsed Laser Techniques in Laser Heated Diamond Anvil Cells for Studying Methane (CH4) and Water (H2O) at Extreme Pressures and Temperatures

    Science.gov (United States)

    Holtgrewe, N.; Lobanov, S.; Mahmood, M.; Goncharov, A. F.

    2017-12-01

    Scientific advancement in the fields of high pressure material synthesis and research on planetary interiors rely heavily on a variety of techniques for probing such extreme conditions, such as laser-heating diamond anvil cells (LHDACs) (Goncharov et al., J. Synch. Rad., 2009) and shock compression (Nellis et al., J. Chem. Phys., 2001/ Armstrong et al., Appl. Phys. Lett., 2008). However, certain chemical properties can create complications in the detection of such extreme states, for example the instability of energetic materials, and detection of these dynamic chemical states by time-resolved methods has proven to be valuable in exploring the kinetics of these materials. Current efforts at the Linac Coherent Light Source (LCLS) for exploring the transitions between different phases of condensed matter (Armstrong et. al., APS Mar. Meeting, 2017/ Radousky et al., APS Mar. Meeting, 2017), and X-ray synchrotron pulsed heating are useful techniques but require large facilities and are not always accessible. Instead, optical properties of materials can serve as a window into the state or structure of species through electronic absorption properties. Pump-probe spectroscopy can be used to detect these electronic properties in time and allow the user to develop a picture of complex dynamic chemical events. Here we present data acquired up to 1.5 megabar (Mbar) pressures and temperatures >3000 K using pulsed transmission/reflective spectroscopy combined with a pulsed LHDAC and time-resolved detection (streak camera) (McWilliams et. al., PNAS, 2015/ McWilliams et al., PRL, 2016). Time-resolved optical properties will be presented on methane (CH4) and water (H2O) at P-T conditions found in icy bodies such as Uranus and Neptune (Lee and Scandolo, Nature Comm., 2011). Our results show that the interiors of Uranus and Neptune are optically opaque at P-T conditions corresponding to the mantles of these icy bodies, which has implications for the unusual magnetic fields of these

  6. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  7. Enhanced oxygen dissociation in a propagating constricted discharge formed in a self-pulsing atmospheric pressure microplasma jet

    Science.gov (United States)

    Schröder, Daniel; Burhenn, Sebastian; Kirchheim, Dennis; Schulz-von der Gathen, Volker

    2013-11-01

    We report on the propagation of a constricted discharge feature in a repetitively self-pulsing microplasma jet operated in helium with a 0.075 vol% molecular oxygen admixture in ambient air environment. The constricted discharge is about 1 mm in width and repetitively ignites at the point of smallest electrode distance in a wedge-shaped electrode configuration, propagates through the discharge channel towards the nozzle, extinguishes, and re-ignites at the inlet at frequencies in the kHz range. It co-exists with a homogeneous, volume-dominated low temperature (T ⋍ 300 K) α-mode glow. Time-resolved measurements of nitrogen molecule C-state and nitrogen molecule ion B-state emission bands reveal an increase of the rotational temperature within the constricted discharge to about 600 K within 50 µs. Its propagation velocity was determined by phase-resolved diagnostics to be similar to the gas velocity, in the order of 40 m s-1. Two-photon absorption laser-induced fluorescence spectroscopy synchronized to the self-pulsing reveals spatial regions of increased oxygen atom densities co-propagating with the constricted discharge feature. The generated oxygen pulse density is about ten times higher than in the co-existing homogeneous α-mode. Densities reach about 1.5 × 1016 cm-3 at average temperatures of 450 K at the nozzle. This enhanced dissociation of about 80% is attributed to the continuous interaction of the constricted discharge to the co-propagating gas volume.

  8. Spectroscopic diagnosis of plasma in atmospheric pressure negative pulsed gas-liquid discharge with nozzle-cylinder electrode

    Science.gov (United States)

    Ming, SUN; Zhan, TAO; Zhipeng, ZHU; Dong, WANG; Wenjun, PAN

    2018-05-01

    The plasma characteristics of a gas-liquid phase discharge reactor were investigated by optical and electrical methods. The nozzle-cylinder electrode in the discharge reactor was supplied with a negative nanosecond pulsed generator. The optical emission spectrum diagnosis revealed that OH (A2∑+ → X2Π, 306–309 nm), N2 (C3Π→B3Πg, 337 nm), O (3p5p→3s5s0, 777.2 nm) and O (3p3p→3s3s0, 844.6 nm) were produced in the discharge plasma channels. The electron temperature (T e) was calculated from the emission relative intensity ratio between the atomic O 777.2 nm and 844.6 nm, and it increased with the applied voltage and the pulsed frequency and fell within the range of 0.5–0.8 eV. The gas temperature (T g) that was measured by Lifbase was in a range from 400 K to 600 K.

  9. Control of Reactive Species Generated by Low-frequency Biased Nanosecond Pulse Discharge in Atmospheric Pressure Plasma Effluent

    Science.gov (United States)

    Takashima, Keisuke; Kaneko, Toshiro

    2016-09-01

    The control of hydroxyl radical and the other gas phase species generation in the ejected gas through air plasma (air plasma effluent) has been experimentally studied, which is a key to extend the range of plasma treatment. Nanosecond pulse discharge is known to produce high reduced electric field (E/N) discharge that leads to efficient generation of the reactive species than conventional low frequency discharge, while the charge-voltage cycle in the low frequency discharge is known to be well-controlled. In this study, the nanosecond pulse discharge biased with AC low frequency high voltage is used to take advantages of these discharges, which allows us to modulate the reactive species composition in the air plasma effluent. The utilization of the gas-liquid interface and the liquid phase chemical reactions between the modulated long-lived reactive species delivered from the air plasma effluent could realize efficient liquid phase chemical reactions leading to short-lived reactive species production far from the air plasma, which is crucial for some plasma agricultural applications.

  10. Experimental and modeling study of the oxidation of acetaldehyde in an atmospheric-pressure pulsed corona discharge

    International Nuclear Information System (INIS)

    Klett, C; Touchard, S; Vega-Gonzalez, A; Redolfi, M; Bonnin, X; Hassouni, K; Duten, X

    2012-01-01

    This paper reports the results obtained for the degradation of acetaldehyde by an atmospheric plasma corona discharge working in a pulsed regime. It was shown that a few hundred ppm of acetaldehyde diluted in a pure N 2 gas flow can be removed up to 80% by a discharge fed with an electric power lower than 1 W. Under the same conditions, adding up to 5% of O 2 allowed the removal of up to 95% of the initial acetaldehyde. The main identified end products were CO 2 , CO and methanol. A quasi-homogeneous zero-dimensional chemical model was developed to investigate the respective efficiency of the discharge and post-discharge periods in the global removal of the pollutant. The identified main pathways of acetaldehyde degradation were quenching of N 2 metastable states during plasma pulses and oxidation by O and OH radicals during the post-discharge. This latter contribution increased with input power because of ozone accumulation in the gas mixture acting as an additional oxygen reservoir. (paper)

  11. Experimental and modeling study of the oxidation of acetaldehyde in an atmospheric-pressure pulsed corona discharge

    Science.gov (United States)

    Klett, C.; Touchard, S.; Vega-Gonzalez, A.; Redolfi, M.; Bonnin, X.; Hassouni, K.; Duten, X.

    2012-08-01

    This paper reports the results obtained for the degradation of acetaldehyde by an atmospheric plasma corona discharge working in a pulsed regime. It was shown that a few hundred ppm of acetaldehyde diluted in a pure N2 gas flow can be removed up to 80% by a discharge fed with an electric power lower than 1 W. Under the same conditions, adding up to 5% of O2 allowed the removal of up to 95% of the initial acetaldehyde. The main identified end products were CO2, CO and methanol. A quasi-homogeneous zero-dimensional chemical model was developed to investigate the respective efficiency of the discharge and post-discharge periods in the global removal of the pollutant. The identified main pathways of acetaldehyde degradation were quenching of N2 metastable states during plasma pulses and oxidation by O and OH radicals during the post-discharge. This latter contribution increased with input power because of ozone accumulation in the gas mixture acting as an additional oxygen reservoir.

  12. Joining of fuel pin end plugs. Pulsed magnetic welding (PMW), pressurized resistance welding (PRW) and their inspection

    International Nuclear Information System (INIS)

    Kamimura, Katsuichiro; Seki, Masayuki

    1996-01-01

    In Power Reactor and Nuclear Fuel Development Corporation, in order to attain the high burnup of FBR fuel, the development of new cladding tube materials mainly aiming at the improvement of swelling resistance has been advanced. Oxide dispersion-strengthened ferritic steel has excellent swelling characteristics and high temperature creep strength, but the strength of its welded parts lowers remarkably. As the result of the investigation of solid phase joining, the conclusion that PMW and PRW are promising was obtained. So far, the manufacture of a welder was started first, the welding test was advanced, and the ultrasonic flaw detection technology of high accuracy was developed for the inspection of welding defects. The features, the principle of welding, the welders and the examples of application of the PMW and the PRW are reported. The features of the ultrasonic inspection apparatus are explained. The inspection apparatus comprises 5 pulse motors for driving probes and one pulse motor for turning a sample. The example of flaw detection test results is shown. (K.I.)

  13. Pulsed laser ablation of silicon with low laser fluence in a low-pressure of ammonia ambient

    International Nuclear Information System (INIS)

    Choo, Cheow-Keong; Tohara, Makoto; Enomoto, Kazuhiro; Tanaka, Katsumi

    2004-01-01

    Silicon was ablated by 532 nm wavelength of Nd:YAG laser in ammonia gas ambient. The influence of laser fluence and gas ambient pressures between 1.33x10 1 to 1.33x10 -5 Pa on the deposited compound was studied by in situ X-ray photoelectron spectroscopy and transmission Fourier transform infrared spectroscopy techniques. The results indicate that the deposited compound is composed of nonstoichiometric silicon nitride (SiN x , x=0-0.84). It has been shown that the composition of nitrogen to silicon is sensitive to the laser fluence; it increases with decreasing laser fluence. However, the ammonia gas ambient in these low pressures range had no influence on the composition of the deposited compound. The reaction of the ablated silicon with low-pressure ambient ammonia is proposed to be occurred on the substrate

  14. Rapid formation of electric field profiles in repetitively pulsed high-voltage high-pressure nanosecond discharges

    International Nuclear Information System (INIS)

    Ito, Tsuyohito; Kobayashi, Kazunobu; Hamaguchi, Satoshi; Czarnetzki, Uwe

    2010-01-01

    Rapid formation of electric field profiles has been observed directly for the first time in nanosecond narrow-gap parallel-plate discharges at near-atmospheric pressure. The plasmas examined here are of hydrogen, and the field measurement is based on coherent Raman scattering (CRS) by hydrogen molecules. Combined with the observation of spatio-temporal light emission profiles by a high speed camera, it has been found that the rapid formation of a high-voltage thin cathode sheath is accompanied by fast propagation of an ionization front from a region near the anode. Unlike well-known parallel-plate discharges at low pressure, the discharge formation process at high pressure is almost entirely driven by electron dynamics as ions and neutral species are nearly immobile during the rapid process. (fast track communication)

  15. Plasma advanced glycation end products (AGEs) and NF-κB activity are independent determinants of diastolic and pulse pressure

    DEFF Research Database (Denmark)

    Sourris, Karly C; Lyons, Jasmine G; Dougherty, Sonia L

    2013-01-01

    was to characterize the relationship between serum AGEs, CLAIS and other risk factors for CV disease in normotensive non-diabetic individuals. Methods: We measured body mass index (BMI), waist-to-hip ratio (WHR), blood pressure, lipid and glucose profile in 44 non-diabetic volunteers (17 female, 27 males......). Carboxymethyl-lysine (CML) was measured by ELISA as a marker for circulating AGEs and NF-κB p65 activity as an inflammatory marker by DNA-binding in peripheral blood mononuclear cells lysates (PBMC). Results: Plasma CML concentrations were related to diastolic blood pressure (r=-0.51, p...

  16. Variations of the flank LLBL thickness as response to the solar wind dynamic pressure and IMF orientation

    Czech Academy of Sciences Publication Activity Database

    Šafránková, J.; Němeček, Z.; Přech, L.; Šimůnek, Jiří; Sibeck, D.; Sauvaud, J. A.

    2007-01-01

    Roč. 112, A7 (2007), A07201/1-A07201/14 ISSN 0148-0227 R&D Projects: GA ČR GA205/06/0875 Institutional research plan: CEZ:AV0Z30420517 Keywords : Low-latitude boundary layer * solar wind-magnetosphere interaction * reconnection Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.953, year: 2007

  17. Pulse Wave Velocity as Marker of Preclinical Arterial Disease: Reference Levels in a Uruguayan Population Considering Wave Detection Algorithms, Path Lengths, Aging, and Blood Pressure

    Directory of Open Access Journals (Sweden)

    Ignacio Farro

    2012-01-01

    Full Text Available Carotid-femoral pulse wave velocity (PWV has emerged as the gold standard for non-invasive evaluation of aortic stiffness; absence of standardized methodologies of study and lack of normal and reference values have limited a wider clinical implementation. This work was carried out in a Uruguayan (South American population in order to characterize normal, reference, and threshold levels of PWV considering normal age-related changes in PWV and the prevailing blood pressure level during the study. A conservative approach was used, and we excluded symptomatic subjects; subjects with history of cardiovascular (CV disease, diabetes mellitus or renal failure; subjects with traditional CV risk factors (other than age and gender; asymptomatic subjects with atherosclerotic plaques in carotid arteries; patients taking anti-hypertensives or lipid-lowering medications. The included subjects (n=429 were categorized according to the age decade and the blood pressure levels (at study time. All subjects represented the “reference population”; the group of subjects with optimal/normal blood pressures levels at study time represented the “normal population.” Results. Normal and reference PWV levels were obtained. Differences in PWV levels and aging-associated changes were obtained. The obtained data could be used to define vascular aging and abnormal or disease-related arterial changes.

  18. Size-controlled growth of ZnO nanowires by catalyst-free high-pressure pulsed laser deposition and their optical properties

    Directory of Open Access Journals (Sweden)

    W. Z. Liu

    2011-06-01

    Full Text Available Single crystalline ZnO nanowires were fabricated on Si (100 substrates by catalyst-free high-pressure pulsed laser deposition. It is found that the nanowires start to form when the substrate temperature and growth pressure exceed the critical values of 700 oC and 700 Pa, and their size strongly depends on these growth conditions. That is, the aspect ratio of the nanowires decreases with increasing temperature or decreasing pressure. Such a size dependence on growth conditions was discussed in terms of surface migration and scattering of ablated atoms. Room-temperature photoluminescence spectrum of ZnO nanowires shows a dominant near-band-edge emission peak at 3.28 eV and a visible emission band centered at 2.39 eV. Temperature-dependent photoluminescence studies reveal that the former consists of the acceptor-bound exciton and free exciton emissions; while the latter varies in intensity with the aspect ratio of the nanowires and is attributed to the surface-mediated deep level emission.

  19. Effects of oxygen partial pressure on the ferroelectric properties of pulsed laser deposited Ba0.8Sr0.2TiO3 thin films

    Science.gov (United States)

    Silva, J. P. B.; Sekhar, K. C.; Almeida, A.; Agostinho Moreira, J.; Pereira, M.; Gomes, M. J. M.

    2013-11-01

    The Ba0.8Sr0.2TiO3 thin films were grown on the Pt-Si substrate at 700 °C by using a pulsed laser deposition technique at different oxygen partial pressure (PO2) in the range of 1-20 Pa and their properties were investigated. It is observed that the PO2 during the deposition plays an important role on the tetragonal distortion ratio, surface morphology, dielectric permittivity, ferroelectric polarization, switching response, and leakage currents of the films. With an increase in PO2, the in-plane strain for the BST films changes from tensile to compressive. The films grown at 7.5 Pa show the optimum dielectric and ferroelectric properties and also exhibit the good polarization stability. It is assumed that a reasonable compressive strain, increasing the ionic displacement, and thus promotes the in-plane polarization in the field direction, could improve the dielectric permittivity. The butterfly features of the capacitance-voltage ( C- V) characteristics and the bell shape curve in polarization current were attributed to the domain reversal process. The effect of pulse amplitude on the polarization reversal behavior of the BST films grown at PO2 of 7.5 Pa was studied. The peak value of the polarization current shows exponential dependence on the electric field.

  20. Production mechanism of atomic nitrogen in atmospheric pressure pulsed corona discharge measured using two-photon absorption laser-induced fluorescence

    International Nuclear Information System (INIS)

    Teramoto, Yoshiyuki; Ono, Ryo; Oda, Tetsuji

    2012-01-01

    To study the production mechanism of atomic nitrogen, the temporal profile and spatial distribution of atomic nitrogen are measured in atmospheric pressure pulsed positive corona discharge using two-photon absorption laser-induced fluorescence. The absolute atomic nitrogen density in the streamer filaments is estimated from decay rate of atomic nitrogen in N 2 discharge. The results indicate that the absolute atomic nitrogen density is approximately constant against discharge energy. When the discharge voltage is 21.5 kV, production yield of atomic nitrogen produced by an N 2 discharge pulse is estimated to be 2.9 - 9.8 × 10 13 atoms and the energy efficiency of atomic nitrogen production is estimated to be about 1.8 - 6.1 × 10 16 atoms/J. The energy efficiency of atomic nitrogen production in N 2 discharge is constant against the discharge energy, while that in N 2 /O 2 discharge increases with discharge energy. In the N 2 /O 2 discharge, two-step process of N 2 dissociation plays significant role for atomic nitrogen production.

  1. Exploring the polymerization of bioactive nano-cones on the inner surface of an organic tube by an atmospheric pressure pulsed micro-plasma jet

    Science.gov (United States)

    Xu, H. M.; Yu, J. S.; Chen, G. L.; Qiu, X. P.; Hu, W.; Chen, W. X.; Bai, H. Y.

    2015-12-01

    In this paper, the successful deposition of acrylic acid polymer (PAA) nano-cones on the inner surface of a polyvinyl chloride (PVC) tube using an atmospheric pressure pulsed plasma jet (APPJ) with acrylic acid (AA) monomer is presented. Optical emission spectroscopy (OES) measurements indicated that various reactive radicals, such as rad OH and rad O, existed in the plasma jet. Moreover, the pulsed current proportionally increased with the increase in the applied voltage. The strengthened stretching vibration of the carbonyl group (Cdbnd O) at 1700 cm-1, shown in the ATR-FTIR spectra, clearly indicated that the PAA was deposited on the PVC surface. The maximum height of the PAA nano-cones deposited by this method ranged from 150 to 200 nm. FTIR and XPS results confirmed the enhanced exposure of the carboxyl groups on the modified PVC surface, which was considered highly beneficial for successfully immobilizing a high density of biomolecules. The XPS data showed that the carbon ratios of the Csbnd OH/R and COOH/R groups increased from 7.03% and 2.6% to 18.69% and 6.81%, respectively (more than doubled) when an Ar/O2 plasma with AA monomer was applied to treat the inner surface of the PVC tube. Moreover, the enhanced attachment density of MC3T3-E1 bone cells was observed on the PVC inner surface coated with PAA nano-cones.

  2. Generation of quasi-monoenergetic protons from a double-species target driven by the radiation pressure of an ultraintense laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Pae, Ki Hong [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Kim, Chul Min, E-mail: chulmin@gist.ac.kr [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of); Nam, Chang Hee, E-mail: chnam@gist.ac.kr [Center for Relativistic Laser Science, Institute for Basic Science, Gwangju 61005 (Korea, Republic of); Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of)

    2016-03-15

    In laser-driven proton acceleration, generation of quasi-monoenergetic proton beams has been considered a crucial feature of the radiation pressure acceleration (RPA) scheme, but the required difficult physical conditions have hampered its experimental realization. As a method to generate quasi-monoenergetic protons under experimentally viable conditions, we investigated using double-species targets of controlled composition ratio in order to make protons bunched in the phase space in the RPA scheme. From a modified optimum condition and three-dimensional particle-in-cell simulations, we showed by varying the ion composition ratio of proton and carbon that quasi-monoenergetic protons could be generated from ultrathin plane targets irradiated with a circularly polarized Gaussian laser pulse. The proposed scheme should facilitate the experimental realization of ultrashort quasi-monoenergetic proton beams for unique applications in high field science.

  3. Randomized Comparison of the Therapeutic Effect of Acupuncture, Massage, and Tachibana-Style-Method on Stiff Shoulders by Measuring Muscle Firmness, VAS, Pulse, and Blood Pressure

    Directory of Open Access Journals (Sweden)

    Kazuhiro Tachibana

    2012-01-01

    Full Text Available To compare the therapeutic efficacy of acupuncture, massage, and Tachibana-Ryojutsu (one of Japanese traditional body balance therapy techniques (SEITAI, on stiff shoulders, the subjects’ muscle firmness, blood pressure, pulse, VAS, and body temperature were measured before and after the treatment. Forty-seven volunteer subjects gave written informed consent to participate in this study. The subjects were randomly divided into three groups to receive acupuncture, massage, or Tachibana-Ryojutsu. Each therapy lasted for 90 seconds. The acupuncture treatment was applied by a retaining-needle at GB-21, massage was conducted softly on the shoulders, and Tachibana-Ryojutsu treated only the muscles and joints from the legs to buttocks without touching the shoulders or backs. The study indicated that the muscle firmness and VAS of the Tachibana-Ryojutsu group decreased significantly in comparison with the acupuncture and massage groups after treatment.

  4. 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.

  5. Influence of surrounding gas, composition and pressure on plasma plume dynamics of nanosecond pulsed laser-induced aluminum plasmas

    Directory of Open Access Journals (Sweden)

    Mahmoud S. Dawood

    2015-10-01

    Full Text Available In this article, we present a comprehensive study of the plume dynamics of plasmas generated by laser ablation of an aluminum target. The effect of both ambient gas composition (helium, nitrogen or argon and pressure (from ∼5 × 10−7 Torr up to atmosphere is studied. The time- and space- resolved observation of the plasma plume are performed from spectrally integrated images using an intensified Charge Coupled Device (iCCD camera. The iCCD images show that the ambient gas does not significantly influence the plume as long as the gas pressure is lower than 20 Torr and the time delay below 300 ns. However, for pressures higher than 20 Torr, the effect of the ambient gas becomes important, the shortest plasma plume length being observed when the gas mass species is highest. On the other hand, space- and time- resolved emission spectroscopy of aluminum ions at λ = 281.6 nm are used to determine the Time-Of-Flight (TOF profiles. The effect of the ambient gas on the TOF profiles and therefore on the propagation velocity of Al ions is discussed. A correlation between the plasma plume expansion velocity deduced from the iCCD images and that estimated from the TOF profiles is presented. The observed differences are attributed mainly to the different physical mechanisms governing the two diagnostic techniques.

  6. First experimental results of particle re-suspension in a low pressure wind tunnel applied to the issue of dust in fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rondeau, Anthony, E-mail: anthony.rondeau@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA, Gif-sur-Yvette 91192 (France); Merrison, Jonathan; Iversen, Jens Jacob [Department of Physics and Astronomy, Institute for Storage Ring Facilities, 8000 Aarhus C (Denmark); Peillon, Samuel; Sabroux, Jean-Christophe; Lemaitre, Pascal; Gensdarmes, François [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES/SCA, Gif-sur-Yvette 91192 (France); Chassefière, Eric [Laboratoire Géosciences Paris Sud (GEOPS), UMR 8148, Université Paris Sud, 91403 Orsay Cedex (France)

    2015-10-15

    Highlights: • The first experimental data of dust re-suspension performed by controlled airflow (in terms of airflow velocity and fluid density). • The effect of the surrounding pressure in the re-suspension mechanism. • The friction (shear velocity) reduction at low pressure in the transient regime (Knudsen number close to one). • The importance of the adhesion forces between particles in dust mobilization by clustering. • The fact that the existing re-suspension models of the relevant literature do not take into account this clustering phenomenon. - Abstract: During the normal operating condition of the future ITER tokamak, a massive production of dust in the toroidal vacuum vessel is expected. This dust, originating from the erosion of tungsten and beryllium internal walls of the torus by the plasma, would be mobilized to some extent during a loss of vacuum accident (LOVA). For safety reasons, it is essential to quantify the re-suspended dust fraction during such an event. Here, we provide preliminary experimental data of dust re-suspension obtained in the wind tunnel of the European Space Agency (ESA) at low pressures (300, 130 and 10 mbar). The experimentations were performed with multilayer deposits. We used two powders with a median diameter at 15.5 μm and 21.8 μm. A negative influence of the low pressure in the re-suspension mechanism is observed. For example, given a re-suspension fraction of 10%, increasing friction shear velocities are derived for decreasing absolute pressures: 300 mbar/0.66 m s{sup −1}; 130 mbar/1.08 m s{sup −1}; and 10 mbar/1.84 m s{sup −1}. In addition, we highlight the friction reduction for Kundsen numbers greater than 0.1 by an analysis of the airflow forces.

  7. Dendritic cells pulsed with tumor cells killed by high hydrostatic pressure inhibit prostate tumor growth in TRAMP mice

    Czech Academy of Sciences Publication Activity Database

    Mikyšková, Romana; Indrová, Marie; Štěpánek, Ivan; Kanchev, Ivan; Bieblová, Jana; Vošahlíková, Š.; Moserová, I.; Truxová, I.; Fučíková, J.; Bartunkova, J.; Spisek, R.; Sedláček, Radislav; Reiniš, Milan

    2017-01-01

    Roč. 6, č. 12 (2017), č. článku e1362528. ISSN 2162-402X R&D Projects: GA MŠk(CZ) LM2015040; GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk ED2.1.00/19.0395; GA ČR GA15-24769S Institutional support: RVO:68378050 Keywords : dendritic cells * docetaxel * high hydrostatic pressure * immunotherapy * prostate cancer Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Immunology Impact factor: 7.719, year: 2016

  8. Gender, race, age, and regional differences in the association of pulse pressure with atrial fibrillation: the Reasons for Geographic and Racial Differences in Stroke study.

    Science.gov (United States)

    Ghazi, Lama; Safford, Monika M; Khodneva, Yulia; O'Neal, Wesley T; Soliman, Elsayed Z; Glasser, Stephen P

    2016-08-01

    Pulse pressure (PP) has been associated with atrial fibrillation (AF) independent of other measures of arterial pressure and other AF risk factors. However, the impact of gender, race, age, and geographic region on the association between PP and AF is unclear. A cross-sectional study of data from 25,109 participants (65 ± 9 years, 54% women, 40% black) from the Reasons for Geographic and Racial Differences in Stroke study recruited between 2003 and 2007 were analyzed. AF was defined as a self-reported history of a previous physician diagnosis or presence of AF on ECG. Multivariable logistic regression models were used to calculate the odds ratio for AF. Interactions for age (race, and region were examined in the multivariable adjusted model. The prevalence of AF increased with widening PP (7.9%, 7.9%, 8.4%, and 11.6%, for PP differences by gender, race, and region were observed. However, there was evidence of significant effect modification by age (interaction P = .0002). For those differ for older versus younger individuals. Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

  9. Left atrium volume index is influenced by aortic stiffness and central pulse pressure in type 2 diabetes mellitus patients: a hemodynamic and echocardiographic study.

    Science.gov (United States)

    Zapolski, Tomasz; Wysokiński, Andrzej

    2013-03-04

    Left atrial volume index (LAVI) has recently emerged as a useful biomarker for risk stratification and risk monitoring in many clinical settings. Many hemodynamic factors such as preload and afterload have an effect on evaluating left atrium function. This study was performed to investigate the relationship between LAVI and aortic stiffness index (ASI) and selected markers characterizing hemodynamic state in patients with type 2 diabetes mellitus (DM2). The study population consisted of 100 patients (56 men, 44 women), 67.2 (±10.9) years old DM2, scheduled for routine coronary angiography. Standard transthoracic echocardiography was used to measure parameters needed for calculation of LAVI and ASI. During invasive procedures, central pulse pressure (CPP) in the ascendens aorta and left ventricle end-diastolic pressure (LVEDP) were recorded. Selected laboratory parameters were obtained, including lipidogram, serum uric acid, hs-CRP, fibrinogen, cTnT, myoglobin, BNP, HbA1C, creatinine, and GFR. Both LAVI and ASI were greater and CPP and LVEDP were markedly elevated in DM2 patients compared to controls. The independent predictors of LAVI were ASI (ß=0.331; p=0.011), CPP (ß=0.312; p=0.020), LVEDP (ß=0.381; p=0.006), HbA1C (ß=0.379; p=0.008), and BNP (ß=0,423; pDM2 patients.

  10. Effect of oxygen partial pressure on the microstructural, optical and gas sensing characterization of nanostructured Gd doped ceria thin films deposited by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    Nagaraju P.

    2017-12-01

    Full Text Available Microstructural properties of 10 mol% gadolinium doped ceria (CeO2 thin films that were deposited on quartz substrate at substrate temperature of 1023 K by using pulsed laser deposition with different oxygen partial pressures in the range of 50–200 mTorr. The influence of oxygen partial pressure on microstructural, morphological, optical and gas sensing characterization of the thin films was systematically studied. The microstructure of the thin films was investigated using X-ray diffraction, atomic force microscopy and Raman spectroscopy. Morphological studies have been carried out using scanning electron microscope. The experimental results confirmed that the films were polycrystalline in nature with cubic fluorite structure. Optical properties of the thin films were examined using UV–vis spectrophotometer. The optical band gap calculated from Tauc’s relation. Gas sensing characterization has been carried at different operating temperatures (room temperature to 523 K for acetone gas. Response and recovery times of the sensor were calculated using transient response plot.

  11. Crystalline and photoluminescence characteristics of YVO{sub 4}:Sm{sup 3+} thin films grown by pulsed laser deposition under oxygen pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hyun Kyoung; Chung, Jong Won; Moon, Byung Kee; Choi, Byung Chun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of); Jeong, Jung Hyun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)], E-mail: jhjeong@pknu.ac.kr; Yi, Soung Soo [Department of Electronic Material Engineering, Silla University, Busan 617-736 (Korea, Republic of); Kim, Jung Hwan [Department of Physics, Dong Eui University, Busan 614-714 (Korea, Republic of); Kim, Kwang Ho [School of Materials Science and Engineering, Busan National University, Busan 609-735 (Korea, Republic of)

    2009-05-15

    YVO{sub 4}:Sm{sup 3+} films were deposited on Al{sub 2}O{sub 3} (0 0 0 1) substrates at various oxygen pressures changing from 13.3 to 46.6 Pa by using the pulsed laser deposition method. The crystallinity and surface morphology of these films were investigated by means of X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The XRD pattern confirmed that YVO{sub 4}:Sm{sup 3+} film has zircon structure and the AFM study revealed that the films consist of homogeneous grains ranging from 100 to 400 nm. The room temperature photoluminescence (PL) spectra showed that the emitted radiation was dominated by a reddish-orange emission peak at 602 nm radiating from the transition of ({sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2}). The crystallinity, surface morphology, and photoluminescence spectra of thin-film phosphors were highly dependent on the deposition conditions, in particular, the substrate temperature. The surface roughness and photoluminescence intensity of these films showed similar behavior as a function of oxygen pressure.

  12. 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

  13. Potential of high isostatic pressure and pulsed electric fields for the processing of potato and pea proteins:structural and techno-functional characterization in model solutions and plant tissue

    OpenAIRE

    Baier, Anne Kathrin

    2016-01-01

    The aim of this thesis was to evaluate the potential of high isostatic pressure and pulsed electric fields for the production of high quality plant proteins. Induced changes in protein solutions and plant tissue of potato and pea were analyzed by means of structural and techno-functional characterization as well as by investigation of diffusion and extractions procedures. The application of high isostatic pressure provides a gentle alternative to conventional heat preservation. Especially ...

  14. The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

    International Nuclear Information System (INIS)

    Kazantzidis, Stelios; Mayer, Lucio; Callegari, Simone; Dotti, Massimo; Moustakas, Leonidas A.

    2017-01-01

    A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N -body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f _g_a_s, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs ( f _g_a_s ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless ( f _g_a_s = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f _g_a_s ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

  15. The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

    Science.gov (United States)

    Kazantzidis, Stelios; Mayer, Lucio; Callegari, Simone; Dotti, Massimo; Moustakas, Leonidas A.

    2017-02-01

    A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N-body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f gas, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs (f gas ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless (f gas = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f gas ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

  16. The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

    Energy Technology Data Exchange (ETDEWEB)

    Kazantzidis, Stelios [Section of Astrophysics, Astronomy and Mechanics, Department of Physics, National and Kapodistrian University of Athens, 15784 Zografos, Athens (Greece); Mayer, Lucio [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zürich, CH-8057 Zürich (Switzerland); Callegari, Simone [Anthropology Institute and Museum, University of Zürich, CH-8057 Zürich (Switzerland); Dotti, Massimo [Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Moustakas, Leonidas A., E-mail: skazantzidis@phys.uoa.gr [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2017-02-10

    A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N -body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f {sub gas}, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs ( f {sub gas} ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless ( f {sub gas} = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f {sub gas} ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

  17. The influence of turbulence and vertical wind profile in wind turbine power curve

    Energy Technology Data Exchange (ETDEWEB)

    Honrubia, A.; Gomez-Lazaro, E. [Castilla-La Mancha Univ., Albacete (Spain). Renewable Energy Research Inst.; Vigueras-Rodriguez, A. [Albacete Science and Technolgy Park, Albacete (Spain)

    2012-07-01

    To identify the influence of turbulence and vertical wind profile in wind turbine performance, wind speed measurements at different heights have been performed. Measurements have been developed using a cup anemometer and a LIDAR equipment, specifically a pulsed wave one. The wind profile has been recorded to study the effect of the atmospheric conditions over the energy generated by a wind turbine located close to the LIDAR system. The changes in the power production of the wind turbine are relevant. (orig.)

  18. 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

  19. Wind energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role wind energy may have in the energy future of the US. The topics discussed in the chapter include historical aspects of wind energy use, the wind energy resource, wind energy technology including intermediate-size and small wind turbines and intermittency of wind power, public attitudes toward wind power, and environmental, siting and land use issues

  20. Electrochemical performance of LiFePO4 modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

    International Nuclear Information System (INIS)

    Li Jianling; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi

    2007-01-01

    Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO 4 particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO 4 and PCVIed LiFePO 4 materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO 4 were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g -1 , respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO 4 , respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R ct ) of PCVIed LiFePO 4 were obviously decreased, indicating a fast kinetics compared to the original LiFePO 4 . The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g -1 at 150th cycle is 1.7 times higher than that of original LiFePO 4

  1. Electrochemical performance of LiFePO{sub 4} modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianling [Department of Physical Chemistry, University of Science and Technology Beijing, No. 30 College Road, Haidian District, Beijing 100083 (China); Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)], E-mail: lijianling@metall.ustb.edu.cn; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi [Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)

    2007-09-25

    Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO{sub 4} particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO{sub 4} and PCVIed LiFePO{sub 4} materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO{sub 4} were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g{sup -1}, respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO{sub 4}, respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R{sub ct}) of PCVIed LiFePO{sub 4} were obviously decreased, indicating a fast kinetics compared to the original LiFePO{sub 4}. The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g{sup -1} at 150th cycle is 1.7 times higher than that of original LiFePO{sub 4}.

  2. Health Monitoring of Composite Overwrapped Pressure Vessels (COPVs) Using Meandering Winding Magnetometer ((MWM(Registered Trademark)) Eddy Current Sensors

    Science.gov (United States)

    Russell, Rick; Grundy, David; Jablonski, David; Martin, Christopher; Washabaugh, Andrew; Goldfine, Neil

    2011-01-01

    There are 3 mechanisms that affect the life of a COPV are: a) The age life of the overwrap; b) Cyclic fatigue of the metallic liner; c) Stress Rupture life. The first two mechanisms are understood through test and analysis. A COPV Stress Rupture is a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. Currently there is no simple, deterministic method of determining the stress rupture life of a COPV, nor a screening technique to determine if a particular COPV is close to the time of a stress rupture failure. Conclusions: Demonstrated a correlation between MWM response and pressure or strain. Demonstrated the ability to monitor stress in COPV at different orientations and depths. FA41 provides best correlation with bottle pressure or stress.

  3. Electric field measurements in a near atmospheric pressure nanosecond pulse discharge with picosecond electric field induced second harmonic generation

    Science.gov (United States)

    Goldberg, Benjamin M.; Chng, Tat Loon; Dogariu, Arthur; Miles, Richard B.

    2018-02-01

    We present an optical electric field measurement method for use in high pressure plasma discharges. The method is based upon the field induced second harmonic generation technique and can be used for localized electric field measurements with sub-nanosecond resolution in any gaseous species. When an external electric field is present, a dipole is induced in the typically centrosymmetric medium, allowing for second harmonic generation with signal intensities which scale by the square of the electric field. Calibrations have been carried out in 100 Torr room air, and a minimum sensitivity of 450 V/cm is demonstrated. Measurements were performed with nanosecond or faster temporal resolution in a 100 Torr room air environment both with and without a plasma present. It was shown that with no plasma present, the field follows the applied voltage to gap ratio, as measured using the back current shunt method. When the electric field is strong enough to exceed the breakdown threshold, the measured field was shown to exceed the anticipated voltage to gap ratio which is taken as an indication of the ionization wave front as it sweeps through the plasma volume.

  4. A "Global Radiosonde and tracked-balloon Archive on Sixteen Pressure levels" (GRASP) going back to 1905 – Part 2: homogeneity adjustments for pilot balloon and radiosonde wind data

    OpenAIRE

    L. Ramella Pralungo; L. Haimberger

    2014-01-01

    This paper describes the comprehensive homogenization of the "Global Radiosonde and tracked balloon Archive on Sixteen Pressure levels" (GRASP) wind records. Many of those records suffer from artificial shifts that need to be detected and adjusted before they are suitable for climate studies. Time series of departures between observations and the National Atmospheric and Oceanic Administration 20th-century (NOAA-20CR) surface pressure only reanalysis have been calculated...

  5. Carbon-based micro-ball and micro-crystal deposition using filamentary pulsed atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Pothiraja, Ramasamy; Bibinov, Nikita; Awakowicz, Peter

    2014-01-01

    Thin plasma filaments are produced by the propagation of ionization waves from a spiked driven electrode in a quartz tube in an argon/methane gas mixture (2400 sccm/2 sccm) at atmospheric pressure. The position of the touch point of filaments on the substrate surface is controlled in our experiment by applying various suitable substrate configurations and geometries of the grounded electrode. The gas conditions at the touch point are varied from argon to ambient air. Based on microphotography and discharge current waveforms, the duration of the filament touching the substrate is estimated to be about one microsecond. Carbon-based materials are deposited during this time at the touch points on the substrate surface. Micro-balls are produced if the filament touch points are saved from ambient air by the argon flow. Under an air admixture, micro-crystals are formed. The dimension of both materials is approximately one micrometre (0.5–2 µm) and corresponds to about 10 10 –10 12 carbon atoms. Neither the diffusion of neutral species nor drift of ions can be reason for the formation of such a big micro-material during this short period of filament–substrate interaction. It is possible that charged carbon-based materials are formed in the plasma channel and transported to the surface of the substrate. The mechanism of this transport and characterization of micro-materials, which are formed under different gas conditions in our experiment, will be studied in the future. (paper)

  6. Influence of surface emission processes on a fast-pulsed dielectric barrier discharge in air at atmospheric pressure

    Science.gov (United States)

    Pechereau, François; Bonaventura, Zdeněk; Bourdon, Anne

    2016-08-01

    This paper presents simulations of an atmospheric pressure air discharge in a point-to-plane geometry with a dielectric layer parallel to the cathode plane. Experimentally, a discharge reignition in the air gap below the dielectrics has been observed. With a 2D fluid model, it is shown that due to the fast rise of the high voltage applied and the sharp point used, a first positive spherical discharge forms around the point. Then this discharge propagates axially and impacts the dielectrics. As the first discharge starts spreading on the upper dielectric surface, in the second air gap with a low preionization density of {{10}4}~\\text{c}{{\\text{m}}-3} , the 2D fluid model predicts a rapid reignition of a positive discharge. As in experiments, the discharge reignition is much slower, a discussion on physical processes to be considered in the model to increase the reignition delay is presented. The limit case with no initial seed charges in the second air gap has been studied. First, we have calculated the time to release an electron from the cathode surface by thermionic and field emission processes for a work function φ \\in ≤ft[3,4\\right] eV and an amplification factor β \\in ≤ft[100,220\\right] . Then a 3D Monte Carlo model has been used to follow the dynamics of formation of an avalanche starting from a single electron emitted at the cathode. Due to the high electric field in the second air gap, we have shown that in a few nanoseconds, a Gaussian cloud of seed charges is formed at a small distance from the cathode plane. This Gaussian cloud has been used as the initial condition of the 2D fluid model in the second air gap. In this case, the propagation of a double headed discharge in the second air gap has been observed and the reignition delay is in rather good agreement with experiments.

  7. Extreme winds in Denmark

    DEFF Research Database (Denmark)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.

    2000-01-01

    (Technical Report, Danish Technical press, 1970) and by Abild (Technical Report R-522 (EN), Riso National Laboratory, 1994). A short discussion of the wind storm on the 3rd of December 1999 is included. It is demonstrated how the data can be applied to non-standard situations where the roughness length......Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity, defined as the 50 yr wind speed (10 min averages) under standard conditions, i.e., 10 m over a homogeneous terrain with the roughness length 0.05 m, The sites are Skjern (15 yr......), Kegnaes (7 yr), Sprogo (20 yr), and Tystofte (16 yr). The measured data are wind speed, wind direction, temperature and pressure. The wind records are cleaned for terrain effects by means of WASP (Mortensew ct al., Technical Report I-666 (EN), Riso National Laboratory, 1993. Vol. 2. User's Guide...

  8. Can Wind Lidars Measure Turbulence?

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob; Gottschall, Julia

    2011-01-01

    Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model captures the effect of volume illumination and coni...

  9. Post-growth annealing of zinc oxide thin films pulsed laser deposited under enhanced oxygen pressure on quartz and silicon substrates

    International Nuclear Information System (INIS)

    Rusop, M.; Uma, K.; Soga, T.; Jimbo, T.

    2006-01-01

    Zinc oxide (ZnO) thin films have been prepared by pulsed laser deposition (PLD) technique at room temperature on quartz and single crystal silicon (1 0 0) substrates. The oxygen ambient gas pressure was attained at 6 Torr during the deposition. The deposited films were post-growth annealed in air at various annealing temperatures for 30 min. The X-ray diffraction (XRD), optical and electrical properties have been measured to study the properties of the films as a function of annealing temperatures. XRD has shown the strength of (0 0 2) peak increases and FWHM value decreases as the annealing temperatures increases from 200 to 600 deg. C. The post-growth annealed at 600 deg. C show dominant c-axis oriented hexagonal wurtize crystal structure and exhibit high average transmittance about 85% in the visible region and very sharp absorption edge at 376 nm with energy band gap of approximately 3.46 eV. Electrical measurement indicates the resistivity decreases with the annealing temperatures up to 600 deg. C, after which it increases with higher annealing temperatures at 800 deg. C. The complex of oxygen vacancy in the ZnO films may be the source of low conductivity in undoped ZnO films

  10. The Role of Ambient Gas and Pressure on the Structuring of Hard Diamond-Like Carbon Films Synthesized by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Andrei C. Popescu

    2015-06-01

    Full Text Available Hard carbon thin films were synthesized on Si (100 and quartz substrates by the Pulsed Laser Deposition (PLD technique in vacuum or methane ambient to study their suitability for applications requiring high mechanical resistance. The deposited films’ surface morphology was investigated by scanning electron microscopy, crystalline status by X-ray diffraction, packing and density by X-ray reflectivity, chemical bonding by Raman and X-ray photoelectron spectroscopy, adherence by “pull-out” measurements and mechanical properties by nanoindentation tests. Films synthesized in vacuum were a-C DLC type, while films synthesized in methane were categorized as a-C:H. The majority of PLD films consisted of two layers: one low density layer towards the surface and a higher density layer in contact with the substrate. The deposition gas pressure played a crucial role on films thickness, component layers thickness ratio, structure and mechanical properties. The films were smooth, amorphous and composed of a mixture of sp3-sp2 carbon, with sp3 content ranging between 50% and 90%. The thickness and density of the two constituent layers of a film directly determined its mechanical properties.

  11. 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.

  12. 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.

  13. Plasma Renalase is Not Associated with Blood Pressure and Brachial-Ankle Pulse Wave Velocity in Chinese Adults With Normal Renal Function

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2016-11-01

    Full Text Available Background/Aims: This study aimed to investigate the association of renalase with blood pressure (BP and brachial-ankle pulse wave velocity (baPWV in order to better understand the role of renalase in the pathogenesis of hypertension and atherosclerosis. Methods: A total of 344 subjects with normal kidney function were recruited from our previously established cohort in Shaanxi Province, China. They were divided into the normotensive (NT and hypertensive (HT groups or high baPWV and normal baPWV on the basis of BP levels or baPWV measured with an automatic waveform analyzer. Plasma renalase was determined through an enzyme-linked immunosorbent assay. Results: Plasma renalase did not significantly differ between HT and NT groups (3.71 ± 0.69 µg/mL vs. 3.72 ± 0.73 μg/mL, P = 0.905 and between subjects with and without high baPWV (3.67 ± 0.66 µg/mL vs. 3.73 ± 0.74 µg/mL, P = 0.505. However, baPWV was significantly higher in the HT group than in the NT group (1460.4 ± 236.7 vs. 1240.7 ± 174.5 cm/s, P Conclusion: Plasma renalase may not be associated with BP and baPWV in Chinese subjects with normal renal function.

  14. Plasma Renalase is Not Associated with Blood Pressure and Brachial-Ankle Pulse Wave Velocity in Chinese Adults With Normal Renal Function.

    Science.gov (United States)

    Wang, Yang; Lv, Yong-Bo; Chu, Chao; Wang, Man; Xie, Bing-Qing; Wang, Lan; Yang, Fan; Yan, Ding-Yi; Yang, Rui-Hai; Yang, Jun; Ren, Yong; Yuan, Zu-Yi; Mu, Jian-Jun

    2016-01-01

    This study aimed to investigate the association of renalase with blood pressure (BP) and brachial-ankle pulse wave velocity (baPWV) in order to better understand the role of renalase in the pathogenesis of hypertension and atherosclerosis. A total of 344 subjects with normal kidney function were recruited from our previously established cohort in Shaanxi Province, China. They were divided into the normotensive (NT) and hypertensive (HT) groups or high baPWV and normal baPWV on the basis of BP levels or baPWV measured with an automatic waveform analyzer. Plasma renalase was determined through an enzyme-linked immunosorbent assay. Plasma renalase did not significantly differ between HT and NT groups (3.71 ± 0.69 µg/mL vs. 3.72 ± 0.73 μg/mL, P = 0.905) and between subjects with and without high baPWV (3.67 ± 0.66 µg/mL vs. 3.73 ± 0.74 µg/mL, P = 0.505). However, baPWV was significantly higher in the HT group than in the NT group (1460.4 ± 236.7 vs. 1240.7 ± 174.5 cm/s, P function. © 2016 The Author(s) Published by S. Karger AG, Basel.

  15. Time-dependent two-temperature chemically non-equilibrium modelling of high-power Ar-N2 pulse-modulated inductively coupled plasmas at atmospheric pressure

    International Nuclear Information System (INIS)

    Tanaka, Yasunori

    2006-01-01

    A time-dependent, two-dimensional, two-temperature and chemical non-equilibrium model was developed for high-power Ar-N 2 pulse-modulated inductively coupled plasmas (PMICPs) at atmospheric pressure. The high-power PMICP is a new technique for sustaining high-power induction plasmas. It can control the plasma temperature and radical densities in the time domain. The PMICP promotes non-equilibrium effects by a sudden application of electric field, even in the high-power density plasmas. The developed model accounts separately for the time-dependent energy conservation equations of electrons and heavy particles. This model also considers reaction heat effects and energy transfer between electrons and heavy particles as well as enthalpy flow resulting from diffusion caused by the particle density gradient. Chemical non-equilibrium effects are also taken into account by solving time-dependent mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from 30 chemical reactions. Transport and thermodynamic properties of Ar-N 2 plasmas are calculated self-consistently using the first order approximation of the Chapman-Enskog method at each position and iteration using the local particle composition, heavy particle temperature and electron temperature. This model is useful to discuss time evolution in temperature, gas flow fields and distribution of chemical species

  16. Pulse radiolysis study on temperature and pressure dependence of the yield of solvated electron in methanol from room temperature to supercritical condition

    International Nuclear Information System (INIS)

    Han, Zhenhui; He, Hui; Lin, Mingzhang; Muroya, Yusa; Katsumura, Yosuke

    2012-09-01

    . Therefore, it was suggested that the supercritical primary alcohols, for example methanol, as the simplest alcohol and an analogue of water, might become a promising substitute of water in a radiolysis study. As our knowledge, the yield of solvated electron in methanol at high temperatures and pressures, especially at supercritical condition, is still unknown now. In this work, the yield of solvated electron in methanol has been investigated at different temperatures from room temperature to supercritical condition by a method of nanosecond pulse radiolysis. By using 4,4'-bipyridyl as a scavenger, the temperature-, pressure- and density-dependent yields of solvated electron, i.e., G-values, have been measured for the first time, which revealing a special density effect on the yield in supercritical methanol. With increasing temperature under 9 MPa, the yield just changes slightly below 230 deg. C, and increases dramatically to peak at around 250 deg. C, after that decreases again. The pressure and density dependence of the yields at elevated temperatures are also measured and discussed. The results imply that, in supercritical region, especially near to critical point, the density effect becomes predominant influence on the yield of radiolysis products. (authors)

  17. 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.

  18. Improvements in or relating to pulsed X-ray units

    International Nuclear Information System (INIS)

    Bichenkov, E.I.; Klypin, V.V.; Palchikov, E.I.

    1983-01-01

    A pulsed X-ray unit comprises a pulsed X-ray tube connected to a discharge capacitor. The discharge capacitor comprises two coaxially arranged cylinders. One cylinder of the discharge capacitor is connected to the X-ray tube and to the high-voltage end of the secondary winding of the pulsed transformer which is shaped as a truncated cone, and is arranged internally of this winding coaxially therewith. The other cylinder of the discharge capacitor is also connected to the X-ray tube and to the low-voltage end of the secondary winding of the pulsed transformer, and is arranged intermediate this winding and the primary winding of the pulsed transformer which is shaped as a hollow cylinder, and connected to the charging device. The cylinders of the discharge capacitor have ports made therein for the passage therethrough of the magnetic flux produced by the windings of the pulsed transformer. (author)

  19. Transitions between states of magnetotail–ionosphere coupling and the role of solar wind dynamic pressure: the 25 July 2004 interplanetary CME case

    Directory of Open Access Journals (Sweden)

    P. E. Sandholt

    2015-04-01

    Full Text Available In a case study, we investigate transitions between fundamental magnetosphere–ionosphere (M-I coupling modes during storm-time conditions (SYM-H between −100 and −160 nT driven by an interplanetary coronal mass ejection (ICME. We combine observations from the near tail, at geostationary altitude (GOES-10, and electrojet activities across the auroral oval at postnoon-to-dusk and midnight. After an interval of strong westward electrojet (WEJ activity, a 3 h long state of attenuated/quenched WEJ activity was initiated by abrupt drops in the solar wind density and dynamic pressure. The attenuated substorm activity consisted of brief phases of magnetic field perturbation and electron flux decrease at GOES-10 near midnight and moderately strong conjugate events of WEJ enhancements at the southern boundary of the oval, as well as a series of very strong eastward electrojet (EEJ events at dusk, during a phase of enhanced ring current evolution, i.e., enhanced SYM-H deflection within −120 to −150 nT. Each of these M-I coupling events was preceded by poleward boundary intensifications and auroral streamers at higher oval latitudes. We identify this mode of attenuated substorm activity as being due to a magnetotail state characterized by bursty reconnection and bursty bulk flows/dipolarization fronts (multiple current wedgelets with associated injection dynamo in the near tail, in their braking phase. The latter process is associated with activations of the Bostrøm type II (meridional current system. A transition to the next state of M-I coupling, when a full substorm expansion took place, was triggered by an abrupt increase of the ICME dynamic pressure from 1 to 5 nPa. The brief field deflection events at GOES-10 were then replaced by a 20 min long interval of extreme field stretching (Bz approaching 5 nT and Bx ≈ 100 nT followed by a major dipolarization (Δ Bz ≈ 100 nT. In the ionosphere the latter stage appeared as a "full-size" stepwise

  20. Wind: new wind markets

    International Nuclear Information System (INIS)

    Cameron, A.

    2005-01-01

    The June 2005 edition of 'Wind Force 12' suggests that wind could generate 12% of global electricity requirements by 2020. But what moves a potential market into an emerging one? Geographical factors include a good wind resource, plenty of open space and the ability to get the generated electricity to end-users. A country's political framework is equally important, with fixed price systems, renewable quota systems and political will all playing a part. Some potential wind markets around the world are thought to have the conditions necessary to become key players in the wind industry. The emerging markets in countries such as Australia, Brazil, Canada, France, Japan and the Philippines are highlighted as examples

  1. Multiple current peaks in room-temperature atmospheric pressure homogenous dielectric barrier discharge plasma excited by high-voltage tunable nanosecond pulse in air

    Energy Technology Data Exchange (ETDEWEB)

    Yang, De-Zheng; Wang, Wen-Chun; Zhang, Shuai; Tang, Kai; Liu, Zhi-jie; Wang, Sen [Key Lab of Materials Modification, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

    2013-05-13

    Room temperature homogenous dielectric barrier discharge plasma with high instantaneous energy efficiency is acquired by using nanosecond pulse voltage with 20-200 ns tunable pulse width. Increasing the voltage pulse width can lead to the generation of regular and stable multiple current peaks in each discharge sequence. When the voltage pulse width is 200 ns, more than 5 organized current peaks can be observed under 26 kV peak voltage. Investigation also shows that the organized multiple current peaks only appear in homogenous discharge mode. When the discharge is filament mode, organized multiple current peaks are replaced by chaotic filament current peaks.

  2. Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

    Science.gov (United States)

    Takashima, Keisuke; Kaneko, Toshiro

    2017-06-01

    The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

  3. Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Russell, Richard; Wincheski, Russell; Jablonski, David; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including

  4. Pore pressure buildup and soil stress relaxation in monopile foundations of offshore wind converters; Porenwasserdruckaufbau und Bodenentfestigung um Pfahlgruendungen von Offshore-Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Cuellar, Pablo; Baessler, Matthias; Georgi, Steven; Ruecker, Werner [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany). Fachbereich 7.2 Ingenieurbau

    2012-09-15

    For the installation of