WorldWideScience

Sample records for vapor conduit means

  1. Vapor sensing by means of a ZnO-on-Si surface acoustic wave resonator

    Martin, S. J.; Schweizer, K. S.; Schwartz, S. S.; Gunshor, R. L.

    Surface Acoustic Wave (SAW) devices can function as sensitive detectors of vapors. The high surface acoustic energy density of the device makes it extremely sensitive to the presence of molecules adsorbed from the gas phase. Mass loading by the adsorbate is the primary mechanism for the surface wave velocity perturbation. If the device is used as the frequency control element of an oscillator, perturbations in wave velocity on the order of 10 parts per billion may be resolved by means of a frequency counter. Zno-on-Si SAW resonators have been examined as vapor sensors. The piezoelectric ZnO layer permits transduction between electrical and acoustic energies, as well as endowing the surface with particular adsorptive properties. These devices exhibit C-values up to 12,000 at a resonant frequency of 109 MHZ. The resonant frequency of the device shifts upon exposure to a vapor-air mixture, with a transient response which is distinct for each of the organic vapors tested. Due to the permeability of the polycrystalline ZnO layer, the instantaneous reversibility of the resonant frequency shift is found to depend on the type of adsorbed molecule.

  2. Vaporization chambers and associated methods

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  3. Mean-Field Approximation to the Hydrophobic Hydration in the Liquid-Vapor Interface of Water.

    Abe, Kiharu; Sumi, Tomonari; Koga, Kenichiro

    2016-03-03

    A mean-field approximation to the solvation of nonpolar solutes in the liquid-vapor interface of aqueous solutions is proposed. It is first remarked with a numerical illustration that the solvation of a methane-like solute in bulk liquid water is accurately described by the mean-field theory of liquids, the main idea of which is that the probability (Pcav) of finding a cavity in the solvent that can accommodate the solute molecule and the attractive interaction energy (uatt) that the solute would feel if it is inserted in such a cavity are both functions of the solvent density alone. It is then assumed that the basic idea is still valid in the liquid-vapor interface, but Pcav and uatt are separately functions of different coarse-grained local densities, not functions of a common local density. Validity of the assumptions is confirmed for the solvation of the methane-like particle in the interface of model water at temperatures between 253 and 613 K. With the mean-field approximation extended to the inhomogeneous system the local solubility profiles across the interface at various temperatures are calculated from Pcav and uatt obtained at a single temperature. The predicted profiles are in excellent agreement with those obtained by the direct calculation of the excess chemical potential over an interfacial region where the solvent local density varies most rapidly.

  4. Dispensing fuel with aspiration of condensed vapors

    Butkovich, M.S.; Strock, D.J.

    1993-08-10

    A vapor recovery process is described, comprising the steps of: fueling a motor vehicle with gasoline by discharging gasoline into a fill opening or filler pipe of a tank of said vehicle through a fuel outlet conduit of a nozzle; emitting gasoline vapors from said tank during said fueling; substantially collecting said vapors during said fueling with a vapor return conduit of said nozzle and passing said vapors through said vapor return conduit in counter current flow relationship to said discharging gasoline in said fuel conduit; conveying said vapors from said vapor return conduit to a vapor return hose; at least some of said vapors condensing to form condensate in said vapor return hose; substantially removing said condensate from said vapor return hose during said fueling with a condensate pickup tube from said nozzle by passing said condensate through said condensate pickup tube in counter current flow relationship to said conveying vapors in said vapor return hose; sensing the presence of gasoline with a liquid sensing tube in said vapor return conduit of said nozzle between inner and outer spouts of said nozzle to detect when said tank of said vehicle is filled with said fuel conduit being within the inner spout of said nozzle; and automatically shutting off said fueling and condensate removing when said liquid sensing tube detects when said tank of said vehicle is filled and fuel enters said vapor return conduit.

  5. Drill pipes and casings utilizing multi-conduit tubulars

    Curlett, H.B.

    1989-01-24

    A seal adapted for use with a multi-conduit well tubular, or the like, is described which consists of: a plate with fluid passages, each passage corresponding to an opening of a conduit of the multiconduit tubular, and a groove on the plate around each passage; and elastomer means partially embeddable into each groove for sealing each conduit of a tubular to a corresponding conduit of another similar tubular.

  6. Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full -- Part 4: Venturi tubes

    International Organization for Standardization. Geneva

    2003-01-01

    ISO 5167-4:2003 specifies the geometry and method of use (installation and operating conditions) of Venturi tubes when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. ISO 5167-4:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-4:2003 is applicable only to Venturi tubes in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of these devices can only be used within specified limits of pipe size, roughness, diameter ratio and Reynolds number. ISO 5167-4:2003 is not applicable to the measurement of pulsating flow. It does not cover the use of Venturi tubes in pipes sized less than 50 mm or more than 1 200 mm, or for where the pipe Reynolds numbers are below 20 000. ISO 5167-4:2003 deals with the three types of classical Venturi tubes: cast, machined and rough welde...

  7. Gastric conduit perforation.

    Patil, Nilesh; Kaushal, Arvind; Jain, Amit; Saluja, Sundeep Singh; Mishra, Pramod Kumar

    2014-08-16

    As patients with carcinoma of the esophagus live longer, complications associated with the use of a gastric conduit are increasing. Ulcers form in the gastric conduit in 6.6% to 19.4% of patients. There are a few reports of perforation of a gastric conduit in the English literature. Almost all of these were associated with serious complications. We report a patient who developed a tension pneumothorax consequent to spontaneous perforation of an ulcer in the gastric conduit 7 years after the index surgery in a patient with carcinoma of the gastroesophageal junction. He responded well to conservative management. Complications related to a gastric conduit can be because of multiple factors. Periodic endoscopic surveillance of gastric conduits should be considered as these are at a higher risk of ulcer formation than a normal stomach. Long term treatment with proton pump inhibitors may decrease complications. There are no guidelines for the treatment of a perforated gastric conduit ulcer and the management should be individualized.

  8. Analysis of weighted mean temperature of Algeria for GNSS water vapor sounding

    Song, DongSeob; Boutiouta, Seddik

    2014-05-01

    Atmospheric water vapour is important for the climate system and a key to understand the hydrological cycle. The hydrological cycle describes the transfer of water in solid, liquid and gaseous form through these phases as well as the physical movement of water within the ecosystem of the earth and between its atmospheres; oceans and continents. Nowadays the accuracy of water vapour estimates based on GNSS observations is comparable to radiosonde and radiometer data. On the other hand, the solution of GNSS precipitable water vapour can be quantified the radiosonde humidity errors and biases with the role of radiosonde observations in the climate studies. The weighted mean temperature in troposphere is a critical parameter in the conversion of wet zenith delay to perceptible water vapour in GNSS Meteorology. In the retrieval of integrated water vapour from GNSS zenith wet delay, effect of temperature is to be taken into account. However, effect of temperature and water vapour partial pressure are interrelated. Therefore, the vertical profiles of temperature are taken into account through a term called weighted mean temperature. In this study, we processed the radiosonde data which are provided by World Meteorological Observation network and surface temperature data at 5 stations in Algeria from 2006 to 2007 to determine weighted mean temperature equation. The coefficients a and b are of weighted mean temperature linear equation were determined by a least square regression method of the 4,944 data pairs after outlier data, which are over 3σ of differences between mean temperature in troposphere and surface temperature, were eliminated. Finally, we determined the Algerian weighted mean temperature model (AWMTM) that the relationship between mean temperature as function of surface temperature for the entire Algerian area, with the RMSE and the correlation coefficient of AWMTM are represented about 6.80 K and 0.75, respectively. The stations which are located in desert

  9. 40 CFR 63.649 - Alternative means of emission limitation: Connectors in gas/vapor service and light liquid service.

    2010-07-01

    ... limitation: Connectors in gas/vapor service and light liquid service. 63.649 Section 63.649 Protection of...: Connectors in gas/vapor service and light liquid service. (a) If an owner or operator elects to monitor... gas/vapor service and for connectors in light liquid service. The data for the two groups...

  10. Empirical model for mean temperature for Indian zone and estimation of precipitable water vapor from ground based GPS measurements

    C. Suresh Raju

    2007-10-01

    Full Text Available Estimation of precipitable water (PW in the atmosphere from ground-based Global Positioning System (GPS essentially involves modeling the zenith hydrostatic delay (ZHD in terms of surface Pressure (Ps and subtracting it from the corresponding values of zenith tropospheric delay (ZTD to estimate the zenith wet (non-hydrostatic delay (ZWD. This further involves establishing an appropriate model connecting PW and ZWD, which in its simplest case assumed to be similar to that of ZHD. But when the temperature variations are large, for the accurate estimate of PW the variation of the proportionality constant connecting PW and ZWD is to be accounted. For this a water vapor weighted mean temperature (Tm has been defined by many investigations, which has to be modeled on a regional basis. For estimating PW over the Indian region from GPS data, a region specific model for Tm in terms of surface temperature (Ts is developed using the radiosonde measurements from eight India Meteorological Department (IMD stations spread over the sub-continent within a latitude range of 8.5°–32.6° N. Following a similar procedure Tm-based models are also evolved for each of these stations and the features of these site-specific models are compared with those of the region-specific model. Applicability of the region-specific and site-specific Tm-based models in retrieving PW from GPS data recorded at the IGS sites Bangalore and Hyderabad, is tested by comparing the retrieved values of PW with those estimated from the altitude profile of water vapor measured using radiosonde. The values of ZWD estimated at 00:00 UTC and 12:00 UTC are used to test the validity of the models by estimating the PW using the models and comparing it with those obtained from radiosonde data. The region specific Tm-based model is found to be in par with if not better than a

  11. Peripheral nerve conduits: technology update

    Arslantunali D

    2014-12-01

    Full Text Available D Arslantunali,1–3,* T Dursun,1,2,* D Yucel,1,4,5 N Hasirci,1,2,6 V Hasirci,1,2,7 1BIOMATEN, Center of Excellence in Biomaterials and Tissue Engineering, Middle East Technical University (METU, Ankara, Turkey; 2Department of Biotechnology, METU, Ankara, Turkey; 3Department of Bioengineering, Gumushane University, Gumushane, Turkey; 4Faculty of Engineering, Department of Medical Engineering, Acibadem University, Istanbul, Turkey; 5School of Medicine, Department of Histology and Embryology, Acibadem University, Istanbul, Turkey; 6Department of Chemistry, Faculty of Arts and Sciences, METU, Ankara, Turkey; 7Department of Biological Sciences, Faculty of Arts and Sciences, METU, Ankara, Turkey *These authors have contributed equally to this work Abstract: Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers and designs (tubular, fibrous, and matrix type are being presented. Keywords: peripheral nerve injury, natural biomaterials, synthetic biomaterials

  12. Drill pipes and casings utilizing multi-conduit tubular; Flerkanals roerstreng

    Curlett, H.B.

    1997-04-23

    The invention relates to a multi-conduit tubular having fluid conduits and electrical conduits, with associated surface fluid and electrical commutators, and downhole sensors for providing surface monitors with instantaneous formation data. Each tubular includes a plurality of uniform linear conduits there through, with a gasket seal plate interposed between joined tubular for assuring a high pressure seal between joined conduits. the seal plate includes an intermediate electrical connector for connecting electrical conduit connectors of one tubular to another. A coupling collar with uniform diameter internal coarse and fine threads joins the tubular ends having similar threads by differential thread action without respective tubular rotation. Each tubular end includes an inter-engaging index recess and index lug, and drive recesses and lugs for maintaining angular registry of the tubular string and for driving one drill tubular with another. A fluid commutator includes a rotating shaft with passages connected to the tubular conduits, and rotating in a manifold having annular grooves in communication with the shaft passages and external fluid sources. An adaptor couples each commutator shaft passage to one or more tubular conduits. Slip rings on a quill shaft and stationary brush means provide electrical continuity from the electrical conduit wires to surface equipment. A cross-over sub includes formation parameter sensors and telemetry equipment in a blocked off portion of a fluid conduit. An annular accumulator connected with the well bore annulus applies a pressure thereto in response to downhole sensors to change the effective density of the drill mud. The multi-conduit tubular is further adapted for use as a well casing to provide downhole access of a plurality of fluids and electrical parameter sensors. 28 figs.

  13. Nonlinear wavetrains in viscous conduits

    Maiden, Michelle; Hoefer, Mark

    2016-11-01

    Viscous fluid conduits provide an ideal system for the study of dissipationless, dispersive hydrodynamics. A dense, viscous fluid serves as the background medium through which a lighter, less viscous fluid buoyantly rises. If the interior fluid is continuously injected, a deformable pipe forms. The long wave interfacial dynamics are well-described by a dispersive nonlinear partial differential equation. In this talk, experiments, numerics, and asymptotics of the viscous fluid conduit system will be presented. Structures at multiple length scales are discussed, including solitons, dispersive shock waves, and periodic waves. Modulations of periodic waves will be explored in the weakly nonlinear regime with the Nonlinear Schrödinger (NLS) equation. Modulational instability (stability) is identified for sufficiently short (long) periodic waves due to a change in dispersion curvature. These asymptotic results are confirmed by numerical simulations of perturbed nonlinear periodic wave solutions. Also, numerically observed are envelope bright and dark solitons well approximated by NLS. This work was partially supported by NSF CAREER DMS-1255422 (M.A.H.) and NSF GRFP (M.D.M.).

  14. Cryovolcanic Conduit Evolution and Eruption on Icy Satellites

    Mitchell, K. L.

    2014-12-01

    In silicate volcanism, such as on Earth or Io, eruptions typically result from fracture formation caused by interaction of tectonic stresses with inflating, pressurized magma sources, leading to transport of melt through an evolving conduit. On icy satellites the paradigm may be similar, resulting from some combination of tidal stresses and expansion of freezing water within, or near the base of, an ice shell. Such a fracture will result in eruption if mass continuity can be established, with buoyancy aided by exsolution and expansion of dissolved volatiles. After onset, conduit shape evolves due to: (1) shear-stresses or frictional erosional; (2) wallrock "bursting" due to massive wall stresses; (3) wall melting or condensation of particles due to heat transfer; or (4) changes in applied stresses. Preliminary thermodynamic and fluid mechanical analysis suggests some initial cooling during ascent resulting from exsolution and expansion of volatiles, thermally buffered by freezing, Conduit contraction may occur, and so evolution towards a deep, gas-filled plume chamber is difficult to accommodate without evoking a co-incidental process. Conduit flaring occurs near the surface where velocities are greatest, enhancing erosion. Here, viscous dissipative heating exceeds adiabatic cooling, and so some boiling (a few wt%) may occur. In contrast with silicate volcanism, decompression to below the triple point will occur within conduit, vent or jet, resulting in rapid freezing and boiling of the remaining water at a 6.8:1 ratio. Subsequent isentropic or adiabatic expansion within erupting jets may result in a few percent net of condensation or sublimation. These effects combined lead to ~4:1-7:1 solid:vapor ratios in the jet for most eruption conditions. These figures are consistent with the ~6:1 inferred in Enceladus' jets, supporting the hypothesis that the Enceladus plume draws from a subsurface body of liquids through a conduit. Similar results are anticipated if

  15. Xylem hydraulic conductivity related to conduit dimensions along chrysanthemum stems.

    Nijsse, J.; Heijden, van der G.W.A.M.; Ieperen, van W.; Keijzer, C.J.; Meeteren, van U.

    2001-01-01

    The stem xylem conduit dimensions and hydraulic conductivity of chrysanthemum plants (Dendranthemaxgrandiflorum Tzvelev cv. Cassa) were analysed and quantified. Simple exponential relations describe conduit length distribution, height dependency of conduit length distribution, and height dependency

  16. Collagen Type I Conduits for the Regeneration of Nerve Defects

    Silvan Klein

    2016-03-01

    Full Text Available To date, reliable data to support the general use of biodegradable materials for bridging nerve defects are still scarce. We present the outcome of nerve regeneration following type I collagen conduit nerve repair in patients with large-diameter nerve gaps. Ten patients underwent nerve repair using a type I collagen nerve conduit. Patients were re-examined at a minimal follow-up of 14.0 months and a mean follow-up of 19.9 months. Regeneration of nerve tissue within the conduits was assessed by nerve conduction velocity (NCV, a static two-point discrimination (S2PD test, and as disability of arm shoulder and hand (DASH outcome measure scoring. Quality of life measures including patients’ perceived satisfaction and residual pain were evaluated using a visual analog scale (VAS. No implant-related complications were observed. Seven out of 10 patients reported being free of pain, and the mean VAS was 1.1. The mean DASH score was 17.0. The S2PD was below 6 mm in 40%, between 6 and 10 mm in another 40% and above 10 mm in 20% of the patients. Eight out of 10 patients were satisfied with the procedure and would undergo surgery again. Early treatment correlated with lower DASH score levels. The use of type I collagen in large-diameter gaps in young patients and early treatment presented superior functional outcomes.

  17. Individual and group meaning-making in an urban third grade classroom: Red fog, cold cans, and seeping vapor

    Southerland, Sherry; Kittleson, Julie; Settlage, John; Lanier, Kimberly

    2005-11-01

    We examined third graders' understandings of condensation using an expanded notion of the Emergent Perspective, a reflexive consideration of individual and group meaning-making situated in the culture of the classroom. Data were collected from two small groups of students in an inquiry-based, urban classroom during a unit on the water cycle. Measures included conceptual pre-/posttests, interviews, written work, and discourse analyses of a science lesson. Although we identified the supportive role of the teacher's explicit assessments of children's ideas, within the small groups, the force that most potently shaped meaning-making was students' persuasive power, which was in part influenced by the rhetorical moves employed. Specifically, students' evaluative comments (a type of rhetorical move) about contributions of other group members seemed to be particularly persuasive in these groups. Evaluative comments, apart from students' academic status, were shown to be an important influence in not only social knowledge production but also in individual internalization. Our explanation focuses on the particular discursive practices as intellectual resources of urban students, but we are also mindful of the cognitive complexity of the material and the developmental abilities of the students.

  18. Pumped Storage and Potential Hydropower from Conduits

    none,

    2015-02-25

    Th is Congressional Report, Pumped Storage Hydropower and Potential Hydropower from Conduits, addresses the technical flexibility that existing pumped storage facilities can provide to support intermittent renewable energy generation. This study considered potential upgrades or retrofit of these facilities, the technical potential of existing and new pumped storage facilities to provide grid reliability benefits, and the range of conduit hydropower opportunities available in the United States.

  19. Phase distribution in complex geometry conduits

    Lahey, R.T. Jr.; Lopez de Bertodano, M.; Jones, O.C. Jr.

    1992-12-31

    Some of the most important and challenging problems in two-phase flow today have to do with the understanding and prediction of multidimensional phenomena, in particular, lateral phase distribution in both simple and complex geometry conduits. A prior review paper summarized the state-of-the-art in the understanding of phase distribution phenomena, and the ability to perform mechanistic multidimensional predictions. The purpose of this paper is to update that review, with particular emphasis on complex geometry conduit predictive capabilities.

  20. Stage 2 vapor recovery system

    Koch, W.H.; Strock, D.J.; Butkovich, M.S.; Hartman, H.B.

    1993-05-25

    A vapor recovery system is described, comprising: a set of elongated underground storage tanks, each storage tank containing a different grade of gasoline; vent pipes; a series of dispensing units; fuel flow lines; vapor return lines; an array of fuel pumps for pumping gasoline from said storage tanks to said dispenser units; an elongated condensate liquid pickup tube; an elongated inner spout providing a fuel conduit and having an outer tip defining a fuel outlet for discharging gasoline into a filler pipe of a motor vehicle tank during fueling; an outer spout assembly; extending into and engaging said spout-receiving socket, said outer spout assembly comprising an outer spout providing a vapor return conduit and defining apertures providing a vapor inlet spaced from said fuel outlet for withdrawing, removing, and returning a substantial amount of gasoline vapors emitted during said fueling; an elongated liquid sensing tube; a manually operable level; a flow control valve assembly; an automatic shutoff valve assembly; and a venturi sleeve assembly positioned in said venturi sleeve receiving chamber.

  1. Impact of In doping on GeTe phase-change materials thin films obtained by means of an innovative plasma enhanced metalorganic chemical vapor deposition process

    Szkutnik, P. D.; Aoukar, M.; Todorova, V.; Angélidès, L.; Pelissier, B.; Jourde, D.; Michallon, P.; Vallée, C.; Noé, P.

    2017-03-01

    We investigated the deposition and the phase-change properties of In-doped GeTe thin films obtained by plasma enhanced metalorganic chemical vapor deposition and doped with indium using a solid delivery system. The sublimated indium precursor flow rate was calculated as a function of sublimation and deposition parameters. Indium related optical emission recorded by means of optical emission spectroscopy during deposition plasma allowed proposing the dissociation mechanisms of the [In(CH3)2N(CH3)2]2 solid precursor. In particular, using an Ar + H2 + NH3 deposition plasma, sublimated indium molecules are completely dissociated and do not induce by-product contamination by addition of nitrogen or carbon in the films. X-ray photoelectron spectroscopy evidences the formation of In-Te bonds in amorphous as-deposited In-doped GeTe films. The formation of an InTe phase after 400 °C annealing is also evidenced by means of X-ray diffraction analysis. The crystallization temperature Tx, deduced from monitoring of optical reflectivity of In-doped GeTe films with doping up to 11 at. % slightly varies as a function of the In dopant level with a decrease of Tx down to a minimum value for an In doping level of about 6-8 at. %. In this In doping range, the structure of crystallized In-GeTe films changes and is dominated by the presence of a crystalline In2Te3 phase. Finally, the Kissinger activation energy for crystallization Ea is showing to monotonically decrease as the indium content in the GeTe film is increased indicating a promising effect of In doping on crystallization speed in memory devices while keeping a good thermal stability for data retention.

  2. MR and CT imaging of pulmonary valved conduits in children and adolescents: normal appearance and complications

    Tenisch, Estelle V.; Alamo, Leonor T.; Gudinchet, Francois [Lausanne University Hospital, Department of Medical Imaging, Lausanne (Switzerland); Sekarski, Nicole [Lausanne University Hospital, Department of Pediatrics, Lausanne (Switzerland); Hurni, Michel [Lausanne University Hospital, Department of Cardiovascular Surgery, Lausanne (Switzerland)

    2014-12-15

    The Contegra registered is a conduit made from the bovine jugular vein and then interposed between the right ventricle and the pulmonary artery. It is used for cardiac malformations in the reconstruction of right ventricular outflow tract. To describe both normal and pathological appearances of the Contegra registered in radiological imaging, to describe imaging of complications and to define the role of CT and MRI in postoperative follow-up. Forty-three examinations of 24 patients (17 boys and 7 girls; mean age: 10.8 years old) with Contegra registered conduits were reviewed. Anatomical description and measurements of the conduits were performed. Pathological items examined included stenosis, dilatation, plicature or twist, thrombus or vegetations, calcifications and valvular regurgitation. Findings were correlated to the echographic gradient through the conduit when available. CT and MR work-up showed Contegra registered stenosis (n = 12), dilatation (n = 9) and plicature or twist (n = 7). CT displayed thrombus or vegetations in the Contegra registered in three clinically infected patients. Calcifications of the conduit were present at CT in 12 patients and valvular regurgitation in three patients. The comparison between CT and/or MR results showed a good correlation between the echographic gradient and the presence of stenosis in the Contegra registered. CT and MR bring additional information about permeability and postoperative anatomy especially when echocardiography is inconclusive. Both techniques depict the normal appearance of the conduit, and allow comparison and precise evaluation of changes in the postoperative follow-up. (orig.)

  3. MRI of the heart following implantation of a left ventricular apico-aortic conduit; Kernspintomografie zur umfassenden Untersuchung des Herzens nach Implantation von linksventrikulaeren apikoaortalen Conduits

    Ruhl, K.M.; Katoh, M.; Guenther, R.W.; Krombach, G.A. [Technische Hochschule Aachen (Germany). Klinik fuer Radiologische Diagnostik; Langebartels, G.; Autschbach, R. [Technische Hochschule Aachen (Germany). Klinik fuer Thorax-, Herz- und Gefaesschirurgie

    2007-06-15

    Purpose: To investigate the potential of ECG-triggered MRI for the evaluation of postoperative anatomy and function of the heart and conduit following implantation of a left-ventricular apico-aortic conduit. Materials and Methods: 5 patients (2 female, 3 male, mean age 72.5 years) were examined using a 1.5 Tesla whole-body MRI (Gyroscan Intera, Philips Medical Systems, Best, The Netherlands) following apico-aortic conduit surgery due to severe aortic valve stenosis. The reason for performing conduit implantation instead of aortic valve replacement was the risk of injuring a bypass graft from prior coronary artery bypass surgery. Cine steady-state-free-precession (SSFP) sequences were used to assess ventricular function, navigator-gated 3D-SSFP and breath-hold, time-resolved contrast-enhanced MR angiography was used to display the postoperative anatomy, and 2D-gradient echo sequences with an inversion pulse to suppress the signal of the healthy myocardium were used to evaluate potential myocardial scarring. Flow sensitive gradient echo sequences were performed to determine the blood flow in the conduit. Results: In all patients the apico-aortic conduit proved to be open with a maximum flow velocity of 126 (+ 43) cm/s. The postoperative anatomy was able to be evaluated in all patients and perioperative myocardial infarction was able to be ruled out. The mean ejection fraction of the left ventricle was 44.2 + 6.2 % with a mean volume of 80 + 20.6 ml per heart beat. (orig.)

  4. Variability of permeability with diameter of conduit

    J A Adegoke; J A Olowofela

    2008-05-01

    An entry length is always observed before laminar flow is achieved in fluid flowing in a conduit. This depends on the Reynolds number of the flow and the degree of smoothness of the conduit. This work examined this region and the point where laminar flow commences in the context of flow through conduit packed with porous material like beads, of known porosity. Using some theoretical assumptions, it is demonstrated that permeability varies from zero at wall-fluid boundary to maximum at mid-stream, creating a permeability profile similar to the velocity profile. An equation was obtained to establish this. We also found that peak values of permeability increase with increasing porosity, and therefore entry length increases with increasing porosity with all other parameters kept constant. A plot of peak permeability versus porosity revealed that they are linearly related.

  5. Chitosan Conduit for Peripheral Nerve Regeneration

    1999-01-01

    Chitosan, the N-deacetylated form of chitin, has good biocompatibility and biodegradability.This paper investigates the feasibility of using chitosan conduits for peripheral nerve regeneration.Cell culture experiments were used to test the material's cytotoxicity and affinity to nerve cells.Conduit implantation experiments were used to study the degradation of the material and the regeneration of injured sciatic nerves.The primary results indicate that chitosan has good mechanical properties, biocompatibility, and biodegradability and it may be a promising biomaterial for peripheral nerve regeneration.

  6. A model of bubble growth leading to xylem conduit embolism.

    Hölttä, T; Vesala, T; Nikinmaa, E

    2007-11-01

    The dynamics of a gas bubble inside a water conduit after a cavitation event was modeled. A distinction was made between a typical angiosperm conduit with a homogeneous pit membrane and a typical gymnosperm conduit with a torus-margo pit membrane structure. For conduits with torus-margo type pits pit membrane deflection was also modeled and pit aspiration, the displacement of the pit membrane to the low pressure side of the pit chamber, was found to be possible while the emboli was still small. Concurrent with pit aspiration, the high resistance to water flow out of the conduit through the cell walls or aspirated pits will make the embolism process slow. In case of no pit aspiration and always for conduits with homogeneous pit membranes, embolism growth is more rapid but still much slower than bubble growth in bulk water under similar water tension. The time needed for the embolism to fill a whole conduit was found to be dependent on pit and cell wall conductance, conduit radius, xylem water tension, pressure rise in adjacent conduits due to water freed from the embolising conduit, and the rigidity and structure of the pits in the case of margo-torus type pit membrane. The water pressure in the conduit hosting the bubble was found to occur almost immediately after bubble induction inside a conduit, creating a sudden tension release in the conduit, which can be detected by acoustic and ultra-acoustic monitoring of xylem cavitation.

  7. Controlling Wavebreaking in a Viscous Fluid Conduit

    Anderson, Dalton; Maiden, Michelle; Hoefer, Mark

    2015-11-01

    This poster will present a new technique in the experimental investigation of dispersive hydrodynamics. In shallow water flows, internal ocean waves, superfluids, and optical media, wave breaking can be resolved by a dispersive shock wave (DSW). In this work, an experimental method to control the location of DSW formation (gradient catastrophe) is explained. The central idea is to convert an initial value problem (Riemann problem) into an equivalent boundary value problem. The system to which this technique is applied is a fluid conduit resulting from high viscosity contrast between a buoyant interior and heavier exterior fluid. The conduit cross-sectional area is modeled by a nonlinear, conservative, dispersive, third order partial differential equation. Using this model, the aim is to predict the breaking location of a DSW by controlling one boundary condition. An analytical expression for this boundary condition is derived by solving the dispersionless equation backward in time from the desired step via the method of characteristics. This is used in experiment to generate an injection rate profile for a high precision piston pump. This translates to the desired conduit shape. Varying the jump height and desired breaking location indicates good control of DSW formation. This result can be improved by deriving a conduit profile by numerical simulation of the full model equation. Controlling the breaking location of a DSW allows for the investigation of dynamics independent of the boundary. Support provided by NSF CAREER DMS-1255422 , NSF EXTREEMS.

  8. Sensing turbulent flow and heat transport in a cave conduit

    Kurtzman, D.; Lucia, F. J.; Jennings, J. W.; Wilson, J. L.; Tyler, S. W.; Jorgensen, A. M.; Dwivedi, R.; Boston, P.; Burger, P.

    2008-12-01

    Cave systems provide an extreme example of complex subsurface porous media, dominated by flow through an interconnected network of conduits. Whether water or air-filled, these flow systems have been largely observed subjectively, with only a few simple quantitative measurements of flow and pressure. In the spring of 2008 a joint campaign of New Mexico Tech and the University of Nevada Reno entered the 210m deep, ~8m "diameter," keyhole shaped, subhorizontal, Left Hand Tunnel, a large air-filled conduit in Carlsbad Caverns, New Mexico, with the intent to observe fluid flow with modern thermally-based instruments. The conduit experiences countercurrent, thermally stratified flow, with mean velocities in each layer less than 0.1m/s. It is part of a geothermally forced, large-scale convection cell. Two instruments were deployed. A distributed temperature sensing (DTS) fiber optic cable was stretched over 1km of the tunnel, and partially suspended by balloons to the roof, to sense spatial and low-frequency (0.01Hz) temporal variations of temperature with a resolution approaching 0.05 degree C. The mean temperature difference between layers was on the order of 0.5 degree and the caveward (subhorizontal) temperature gradient was 1 degree/400m. Influences of connecting subvertical shafts, wet areas of the cave, human activity, and diurnal fluctuations were observed. The second instrument, a 7m tall tower with an array of eight 300Hz thermocouple temperature sensors, with a sensitivity approaching 0.005 degree, was deployed 200m into the tunnel and used to detect high- frequency temperature fluctuations associated with turbulence and the stratified flow. Turbulence structure of each layer was similar. Temperature fluctuation (and turbulence intensity?) was significantly greater near the boundary between layers and its steep vertical gradient of mean temperature. Results from this 3-day campaign, as limited as they are, suggest that there is a wealth of information and

  9. Vegetable cells in urinary samples of patients with bricker ileal conduit.

    Planinšek, Tanja; Kladnik, Aleš; Pohar-Marinšek, Ziva; Fležar, Margareta Strojan

    2014-02-01

    During routine cytopathological evaluation of urines for malignant cells we have occasionally noticed vegetable cells that were only present in patients with Bricker ileal conduit. We wanted to identify the means and sources of contamination of urinary samples from these patients. During the period between May and November 2010, 637 urinary samples were routinely evaluated for malignant cells. Among them were 13 urinary samples from Bricker ileal conduit which we rescreened. We prepared all urinary samples by membrane filtration and stained them according to Papanicolaou. Subsequently, we prepared samples from ostomy adhesives made by Coloplast and by ConvaTec which are used to secure the ostomy bag onto urostomy. We also took samples from different constituents (hydrocolloids) of ostomy adhesives. On the cytopathological review, we found vegetable cells along with intestinal mucosa cells in urinary samples of seven patients with Bricker ileal conduit. With the light microscopic examination of the samples prepared from different ostomy adhesives, we found vegetable cells only in Coloplast adhesives. In preparations of hydrocolloids, we found vegetable cells only in guar gum. They were morphologically identical to those found in urine samples of patients with Bricker ileal conduit and in Sensura and Sensura Xpro (Coloplast) ostomy adhesives. We determined that the origin of vegetable cells in urines from Bricker ileal conduit is the ostomy adhesive. The vegetable cells differ from human intestinal epithelial cells regarding size, shape, and color so it is difficult to misinterpret them as dysplastic cells.

  10. Assessment of conduit artery vasomotion using photoplethysmography

    Kanders, Karlis; Grabovskis, Andris; Marcinkevics, Zbignevs; Aivars, Juris Imants

    2013-11-01

    Vasomotion is a spontaneous oscillation of vascular tone. The phenomenon has been observed in small arterioles and capillaries as well as in the large conduit arteries. The layer of smooth muscle cells that surrounds a blood vessel can spontaneously and periodically change its tension and thereby the arterial wall stiffness also changes. As the understanding of the phenomenon is still rather obscure, researchers would benefit from a low-cost and reliable investigation technique such as photoplethysmography (PPG). PPG is an optical blood pulsation measurement technique that can offer substantial information about the arterial stiffness. The aims of this pilot study were to evaluate the usefulness of the PPG technique in the research of vasomotion and to investigate vasomotion in the relatively large conduit arteries. Continuous 15 minute long measurements of posterior tibial artery wall stiffness were taken. Artery diameter, electrocardiogram, blood pressure and respiration were also simultaneously registered. Fast Fourier Transform power spectra were calculated to identify unique stiffness oscillations that did not correspond to fluctuations in the systemic parameters and thus would indicate vasomotion. We concluded that photoplethysmography is a convenient method for the research of the vasomotion in large arteries. Local stiffness parameter b/a is more accurate to use and easier to measure than the pulse wave velocity which describes stiffness of a segment of an artery. Conduit arteries might exhibit a low amplitude high frequency vasomotion ( 9 to 27 cycles per minute). Low frequency vasomotion is problematic to distinguish from the passive oscillations imposed by the arterial pressure.

  11. Thermal damping and retardation in karst conduits

    A. J. Luhmann

    2014-08-01

    Full Text Available Water temperature is a non-conservative tracer in the environment. Variations in recharge temperature are damped and retarded as water moves through an aquifer due to heat exchange between water and rock. However, within karst aquifers, seasonal and short-term fluctuations in recharge temperature are often transmitted over long distances before they are fully damped. Using analytical solutions and numerical simulations, we develop relationships that describe the effect of flow path properties, flow-through time, recharge characteristics, and water and rock physical properties on the damping and retardation of thermal peaks/troughs in karst conduits. Using these relationships, one can estimate the thermal retardation and damping that would occur under given conditions with a given conduit geometry. Ultimately, these relationships can be used with thermal damping and retardation field data to estimate parameters such as conduit diameter. We also examine sets of numerical experiments where we relax some of the assumptions used to develop these relationships, testing the effects of variable diameter, variable velocity, open channels, and recharge shape on thermal damping and retardation to provide some constraints on uncertainty. Finally, we discuss a tracer experiment that provides field confirmation of our relationships. High temporal resolution water temperature data are required to obtain sufficient constraints on the magnitude and timing of thermal peaks and troughs in order to take full advantage of water temperature as a tracer.

  12. Liver Transplantation Utilizing Mixed Biologic and Synthetic Arterial Conduits

    Marcio F. Chedid

    2016-01-01

    Full Text Available Arterial conduits are necessary in nearly 5% of all liver transplants and are usually constructed utilizing segments of donor iliac artery. However, available segments of donor iliac artery may not be lengthy enough or may not possess enough quality to enable its inclusion in the conduit. Although there are few reports of arterial conduits constructed solely utilizing prosthetic material, no previous reports of conduits composed of a segment of donor iliac artery and prosthetic material (mixed biologic and synthetic arterial conduits were found in the medial literature to date. Two cases reporting successful outcomes after creation of mixed biologic and prosthetic arterial conduits are outlined in this report. Reason for creation of conduits was complete intimal dissection of the recipient’s hepatic artery in both cases. In both cases, available segments of donor iliac artery were not lengthy enough to bridge infrarenal aorta to porta hepatis. Both patients have patent conduits and normally functioning liver allografts, respectively, at 4 and 31 months after transplant. Mixed biologic and synthetic arterial conduits constitute a viable technical option and may offer potential advantages over fully prosthetic arterial conduits.

  13. Optimization of Design of Steam Turbine Exhaust Conduits

    A. S. Goldin

    2014-01-01

    Full Text Available Improving effectiveness turbine was and remains a key issue for today. In order to improve the efficiency of the turbine is necessary to reduce losses in the steam turbine exhaust conduit.This paper presents the design optimization exhaust conduit steam turbine K-27-2.9 produced by JSC «KTW» at the design stage. The aims of optimizing the design were: decreasing hydraulic resistance of the conduit, reduction of non-uniformity of the flow at the outlet of the conduit, equalizing steam flow ahead of the condenser tube bundle.The conduit models were made and flows in it were simulated in environment of the Solid Works and its application COSMOS Flo Works.As the initial conduit model was selected exhaust conduit of turbine PT-25/34-3.4 produced by JSC «KTW». Was obtained by the calculated velocity field at the outlet of the conduit. The analysis of the calculation results revealed the necessity of changes to the initial design of the conduit. The changes were accompanied by calculating currents flow in the conduit, and assessed the impact of design changes on the nature of the course. Further transformation of the construction of the conduit was held on the results of these calculations. Construction changes are not touched by the outer geometry of the conduit, and were introduced to meet technological.According to calculation results, conclusions were drawn and selected three versions of the conduit.Given are the research results for the initial conduit model and modified design versions. In order to evaluate the flow degree of irregularity the momentum factor (Bussinesku factor for outlet crosssection of the selected conduit design version. Analysis of the research results made it possible to determine optimum design of the exhaust conduit.Introducing the suggested alterations in the conduit design will result in improvement of heat exchange in the condenser, an increase in reliability of the tube bundle operation, a decrease in noise and

  14. Alkylation of Chitosan as Nerve Conduit Biomaterial

    邓劲光; 公衍道; 程明愚; 赵南明; 张秀芳

    2002-01-01

    Chitosan under physiological conditions is a degradable and biocompatible biomaterial with a wide variety of useful physicochemical properties. However, as a nerve conduit biomaterial, its solubility was very low, so chitosan was modified chemically to enhance its solubility. The free amino groups of long molecular chains in chitosan are responsible for its solubility, and the solubility could be adjusted by controlling the free amidogen capacity with N-alkylation. The results show that the solubility of N-alkylation chitosan is increased to 10%, which is an increase of 500%.

  15. Gas slug ascent through rheologically stratified conduits

    Capponi, Antonio; James, Mike R.; Lane, Steve J.

    2016-04-01

    Textural and petrological evidence has indicated the presence of viscous, degassed magma layers at the top of the conduit at Stromboli. This layer acts as a plug through which gas slugs burst and it is thought to have a role in controlling the eruptive dynamics. Here, we present the results of laboratory experiments which detail the range of slug flow configurations that can develop in a rheologically stratified conduit. A gas slug can burst (1) after being fully accommodated within the plug volume, (2) whilst its base is still in the underlying low-viscosity liquid or (3) within a low-viscosity layer dynamically emplaced above the plug during the slug ascent. We illustrate the relevance of the same flow configurations at volcanic-scale through a new experimentally-validated 1D model and 3D computational fluid dynamic simulations. Applied to Stromboli, our results show that gas volume, plug thickness, plug viscosity and conduit radius control the transition between each configuration; in contrast, the configuration distribution seems insensitive to the viscosity of magma beneath the plug, which acts mainly to deliver the slug into the plug. Each identified flow configuration encompasses a variety of processes including dynamic narrowing and widening of the conduit, generation of instabilities along the falling liquid film, transient blockages of the slug path and slug break-up. All these complexities, in turn, lead to variations in the slug overpressure, mirrored by changes in infrasonic signatures which are also associated to different eruptive styles. Acoustic amplitudes are strongly dependent on the flow configuration in which the slugs burst, with both acoustic peak amplitudes and waveform shapes reflecting different burst dynamics. When compared to infrasonic signals from Stromboli, the similarity between real signals and laboratory waveforms suggests that the burst of a slug through a plug may represent a viable first-order mechanism for the generation of

  16. Delayed complication of pelvic lymphocele: Ileal conduit obstruction

    Sanket S Bankar

    2015-01-01

    Full Text Available Radical cystectomy is the standard treatment for muscle invasive bladder cancer. Lymphocele is a common sequalae of pelvic lymphadenectomy. We report an unusual presentation of pelvic lymphocele developing after radical cystectomy reconstructed with an ileal conduit where the patient developed obstruction of the ileal conduit loop due to external pressure of the lymphocele. Catheter drainage of the conduit relieved the symptoms and a computerized tomography scan showed a large lymphocele causing acute angulation and resultant obstruction of the ileal conduit. The patient was treated with percutaneous drainage of the lymphocele and remains symptom-free on follow-up at 1 year.

  17. Corrosion detection and monitoring in steam generators by means of ultrasound; Deteccion y monitoreo de corrosion por medio de ultrasonido en generadores de vapor

    Chacon Nava, Jose G.; Calva, Mauricio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Fuentes Samaniego, Raul [Universidad Autonoma de Nuevo Leon (Mexico); Peraza Garcia, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    The tube and component failures in steam generators due to corrosion cause huge economical losses. In this article the internal corrosion processes (hydrogen attack) and high temperature corrosion are described, as well as the ultrasound techniques used for its detection. The importance of obtaining corrosion rates, which are fundamental parameters for the detection of the tube`s residual life. The purpose is to prevent possible failures that would diminish the power plant availability. [Espanol] Las fallas de tuberia en componentes de generadores de vapor debidas a corrosion ocasionan considerables perdidas economicas. En este articulo se describen los procesos de corrosion interna (ataque por hidrogeno) y corrosion en alta temperatura, asi como tecnicas de ultrasonido empleadas para su deteccion. Se destaca la importancia de obtener valores de velocidad de corrosion, que es un parametro fundamental para la determinacion de la vida residual de tuberias. El proposito es poder prevenir posibles fallas que disminuyan la disponibilidad de centrales termoelectricas.

  18. How to quantify conduits in wood?

    Alexander eScholz

    2013-03-01

    Full Text Available Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

  19. How to quantify conduits in wood?

    Scholz, Alexander; Klepsch, Matthias; Karimi, Zohreh; Jansen, Steven

    2013-01-01

    Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

  20. Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.

    Jiang, Xu; Mi, Ruifa; Hoke, Ahmet; Chew, Sing Yian

    2014-05-01

    Fibre structures represent a potential class of materials for the formation of synthetic nerve conduits due to their biomimicking architecture. Although the advantages of fibres in enhancing nerve regeneration have been demonstrated, in vivo evaluation of fibre size effect on nerve regeneration remains limited. In this study, we analyzed the effects of fibre diameter of electrospun conduits on peripheral nerve regeneration across a 15-mm critical defect gap in a rat sciatic nerve injury model. By using an electrospinning technique, fibrous conduits comprised of aligned electrospun poly (ε-caprolactone) (PCL) microfibers (981 ± 83 nm, Microfiber) or nanofibers (251 ± 32 nm, Nanofiber) were obtained. At three months post implantation, axons regenerated across the defect gap in all animals that received fibrous conduits. In contrast, complete nerve regeneration was not observed in the control group that received empty, non-porous PCL film conduits (Film). Nanofiber conduits resulted in significantly higher total number of myelinated axons and thicker myelin sheaths compared to Microfiber and Film conduits. Retrograde labeling revealed a significant increase in number of regenerated dorsal root ganglion sensory neurons in the presence of Nanofiber conduits (1.93 ± 0.71 × 10(3) vs. 0.98 ± 0.30 × 10(3) in Microfiber, p regeneration. These results could provide useful insights for future nerve guide designs.

  1. Vapor Bubbles

    Prosperetti, Andrea

    2017-01-01

    This article reviews the fundamental physics of vapor bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor bubbles in an immiscible liquid.

  2. Application of a venous conduit as a stent for repairing rabbit facial nerve injury

    2007-01-01

    each animal were observed daily.② Animals were anesthetized at 5,10 and 15 weeks after operation for observing the structural change of the venous conduit,the appearance of regenerated nerve,and the relationship between conduit and peripheral muscle tissue.③The action potential and latency of bilateral nerves of animals were measured by electrophysiologic examination,and nerve conduction velocity was calculated.④Neural myelination and neurite growth were observed by histological staining using an optical microscope.RESULTS:Thirty-three New Zealand rabbits were involved in the final analysis.①mmediately following the operation,vibrissae activity and orbicularis otis muscle activity of the upper lip on venous conduit side were more prominent,and their amplitudes of movement were larger as compared with autogenous nerve side.②At postoperative 10 weeks,by visual inspection,we found that on the venous conduit side,the venous conduit exhibited membrane structure which encased regenerated nerve.Regenerated nerve adhered to the muscle edge of orbicularis oris muscle.Muscle and nerve could be separated with a forceps.The muscle of musculus orbicularis oris of rabbit was darker and thicker as compared with autogenous nerve side.After the venous conduit was longitudinally split,the regenerated nerve and nerves at two the severed ends were connected together.When compared with postoperative 5 weeks,the connected nerve was thickened,texture was tough and its middle part was thicker than its two ends.On the autogenous nerve side,the regenerated nerve stem was enwrapped by scar tissue.It was bulky and adhered to peripheral muscle.Its neural profile structure was unclear.The two stomas were obviously enlarged.③At postoperative 10 weeks and 15 weeks,nerve action potentials could be elicited from both the venous conduit and autologous nerve side.The mean nerve conduction velocity on the venous conduit side was greater than that of the autologous nerve side

  3. [Reconstruction of the pulmonary outflow tract without external conduit].

    Yoshimura, N; Yamaguchi, M; Oka, S; Ootaki, Y; Yoshida, M; Hayashi, T; Shinkawa, T; Tei, T; Kuroe, K; Kido, S; Tsukuda, K; Oshima, Y

    2001-07-01

    Between October 1987 and December 2000, 50 patients underwent reconstruction of the pulmonary outflow tract without external conduit. The primary malformation was tetralogy of Fallot with pulmonary atresia in 37, double outlet of right ventricle in 4, corrected transposition of the great arteries in 4, transposition of the great arteries with ventricular septal defect and pulmonary stenosis in 4, and double outlet of left ventricle in 2. Mean age at operation was 7.2 years, and mean body weight was 18.3 kg. To reconstruct posterior wall of the pulmonary outflow tract, interposition of autologous pericardium was performed in 24, direct anastomosis between pulmonary trunk and ventriculotomy in 13, longitudinal incision from ventriculotomy through pulmonary trunk in 12, and interposition of left atrial appendage in 1. Anterior wall was reconstructed with monocusp valved outflow patch (MVOP). There was one hospital death and no late death. At 10 years, the freedom from reoperation for pulmonary outflow tract obstruction was 100%, and freedom from reoperation for any cause was 86.6%. Transcatheter stenting for peripheral pulmonary stenosis was performed in 6 patients 2 to 10 months after operation.

  4. Spotlight on CERN : Le code de conduite

    CERN Video Productions

    2010-01-01

    Cette année 2010, le démarrage du LHC a été le témoignage de la réussite de la collaboration scientifique au CERN, rapprochant les personnes, hommes et femmes, tous ensemble pour la plus grande des réalisations. Cette collaboration nécessite une ouverture sur la diversité basée sur des valeurs solides. Pour s’assurer que l'Organisation continue sur la voie du succès, un consensus a été atteint sur des valeurs caractérisant le CERN et celles-ci ont été regroupées dans un Code de conduite, décrivant la norme de base du comportement que nous pouvons tous espérer de nous-mêmes et de nos collègues sur notre lieu de travail. Entrevues avec Rolf Heuer, Directeur Général du CERN, Anne-Sylvie Catherin, Chef du Département des Ressources Humaines, et Vincent Vuillemin, Ombuds au CERN.

  5. Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit

    Pei-xun Zhang

    2015-01-01

    Full Text Available The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2-8 weeks, the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  6. Biological conduit small gap sleeve bridging method for peripheral nerve injury:regeneration law of nerve ifbers in the conduit

    Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Feng Xue#; Na Han; Tian-bing Wang; Bao-guo Jiang

    2015-01-01

    The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair periph-eral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good his-tocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve ifbers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2–8 weeks), the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objec-tive and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  7. Guided regeneration with resorbable conduits in experimental peripheral nerve injuries

    Nicoli Aldini, N.; Fini, M; Rocca, M; Giavaresi, G.; Giardino, R.

    2000-01-01

    Guided tissue regeneration is a new approach in the reconstructive surgery of peripheral nerves. Artificial conduits can be constructed from biodegradable polymers. Lactic/caproic acid copolymers and polyphospazenes are biocompatible materials with a slow resorption rate. Conduits made from either poly-[l-lactide-co-6-caprolatone] or poly-[bis-(ethylalanate)-phosphazene] were assessed for use as guides for nerve regeneration in experimental animals. Under general anesthesia and by using a mic...

  8. Computational fluid dynamic simulations of cavopulmonary connections with an extracardiac lateral conduit.

    Migliavacca, F; de Leval, M R; Dubini, G; Pietrabissa, R; Fumero, R

    1999-04-01

    Complex congenital heart defects due to the absence of a ventricular chamber can often be treated by the Fontan surgical procedure. The objective of this work was to quantify the haemodynamics in the Fontan operation (cavopulmonary connection) with extracardiac lateral conduit. Four different models based on the finite element method were constructed with different lengths of inferior anastomosis (range 18-25 mm) and inclinations of the conduit (33 and 47.5 degrees). Mass conservation and Navier-Stokes equations were solved by means of the FIDAP code, based on the finite element method. The left-to-right pulmonary flow ratio and percentage inferior caval blood to the left lung were the highest with the smallest anastomosis and highest inclination: 1.35 and 83.26%, respectively. Dissipated power percentage was higher with the largest anastomosis than with the smallest (19.4 vs 15.8%). It was concluded that, when performing a total cavopulmonary connection, an extracardiac lateral conduit: (i) diverts more flow to the left lung, and (ii) shows higher energy losses when compared with a connection with intra-atrial tunnel. This study could be useful to evaluate the incidence of pulmonary arteriovenous malformations.

  9. Cryopreserved allograft veins as alternative coronary artery bypass conduits: early phase results.

    Laub, G W; Muralidharan, S; Clancy, R; Eldredge, W J; Chen, C; Adkins, M S; Fernandez, J; Anderson, W A; McGrath, L B

    1992-11-01

    Traditional autologous conduits are sometimes unavailable or unsuitable to permit total revascularization during coronary artery bypass grafting. In these patients the results of using nonautologous alternative conduits has been disappointing. Encouraged by the excellent long-term results seen with cryopreserved allograft valves, a clinical protocol was developed to evaluate the use of a commercially cryopreserved allograft saphenous vein (CPV). Our protocol consisted of using CPV when left internal mammary arteries and autologous saphenous vein grafts were unavailable or unsuitable for complete revascularization. Blood group (ABO) typed CPVs were thawed and implanted as required using standard surgical techniques. From December 1989 through June 1991, 19 of 1,602 patients who underwent coronary revascularization had CPVs implanted (1.2%). There were no operative deaths. An attempt was made to evaluate the patency of all grafts with coronary arteriography or ultrafast computed tomographic scans. Fourteen patients were available for patency evaluation. Patency rate in the 14 patients studied at a mean of 7 +/- 2 months (range, 2 to 16 months) were: internal mammary artery, 93% (14/15); saphenous vein graft, 80% (4/5); and CPV, 41% (7/17). The patency of the CPV was significantly less than the patency rate for the saphenous vein and internal mammary artery (p = 0.004). We conclude that the short-term patency rate of CPVs is inferior to that of autologous vessels. Due to its poor patency, we recommend that CPV should only be used when no other autologous conduit is available.

  10. Biological and artificial nerve conduit for repairing peripheral nerve defect

    Xuetao Xie; Changqing Zhang

    2006-01-01

    OBJECTIVE: Recently, with the development of biological and artificial materials, the experimental and clinical studies on application of this new material-type nerve conduit for treatment of peripheral nerve defect have become the hotspot topics for professorial physicians.DATA SOURCES: Using the terms "nerve conduits, peripheral nerve, nerve regeneration and nerve transplantation" in English, we searched Pubmed database, which was published during January 2000 to June 2006, for the literatures related to repairing peripheral nerve defect with various materials. At the same time, we also searched Chinese Technical Scientific Periodical Database at the same time period by inputting" peripheral nerve defect, nerve repair, nerve regeneration and nerve graft" in Chinese.STUDY SELECTION: The materials were firstly selected, and literatures about study on various materials for repairing peripheral nerve defect and their full texts were also searched. Inclusive criteria: nerve conduits related animal experiments and clinical studies. Exclusive criteria: review or repetitive studies.DATA EXTRACTION: Seventy-nine relevant literatures were collected and 30 of them met inclusive criteria and were cited.DATA SYNTHESTS: Peripheral nerve defect, a commonly seen problem in clinic, is difficult to be solved. Autogenous nerve grafting is still the gold standard for repairing peripheral nerve defect, but because of its application limitation and possible complications, people studied nerve conduits to repair nerve defect. Nerve conduits consist of biological and artificial materials.CONCLUSION: There have been numerous reports about animal experimental and clinical studies of various nerve conduits, but nerve conduit, which is more ideal than autogenous nerve grafting, needs further clinical observation and investigation.

  11. Sciatic nerve repair using adhesive bonding and a modiifed conduit

    Xiangdang Liang; Hongfei Cai; Yongyu Hao; Geng Sun; Yaoyao Song; Wen Chen

    2014-01-01

    When repairing nerves with adhesives, most researchers place glue directly on the nerve stumps, but this method does not ifx the nerve ends well and allows glue to easily invade the nerve ends. In this study, we established a rat model of completely transected sciatic nerve injury and re-paired it using a modiifed 1 cm-length conduit with inner diameter of 1.5 mm. Each end of the cylindrical conduit contains a short linear channel, while the enclosed central tube protects the nerve ends well. Nerves were repaired with 2-octyl-cyanoacrylate and suture, which complement the function of the modiifed conduit. The results demonstrated that for the same conduit, the av-erage operation time using the adhesive method was much shorter than with the suture method. No signiifcant differences were found between the two groups in sciatic function index, motor evoked potential latency, motor evoked potential amplitude, muscular recovery rate, number of medullated nerve fibers, axon diameter, or medullary sheath thickness. Thus, the adhesive method for repairing nerves using a modiifed conduit is feasible and effective, and reduces the operation time while providing an equivalent repair effect.

  12. Nanofiber-reinforced biological conduit in cardiac surgery: preliminary report.

    Guhathakurta, Soma; Galla, Satish; Ramesh, Balasundari; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Cherian, Kotturathu Mammen

    2011-06-01

    Several options are available for right ventricular outflow tract reconstruction, including commercially available bovine jugular vein and cryo-preserved homografts. Homograft non-availability and the problems of commercially available conduits led us to develop indigenously processed bovine jugular vein conduits with competent valves. They were made completely acellular and strengthened by non-conventional cross-linking without disturbing the extracellular matrix, which improved the luminal surface characteristics for hemocompatibility. Biocompatibility in vitro and in vivo, along with thermal stability, matrix stability, and mechanical strength have been evaluated. Sixty-nine patients received these conduits for right ventricular outflow tract reconstruction. Seven conduits dilated and 4 required replacement. To counteract dilatation, biodegradable polymeric nanofibers in various combinations and in isolation (collagen, polycaprolactone, polylactic acid) were characterized and used to reinforce the conduit circumferentially. Physical validation by mechanical testing, scanning electron microscopy, and in-vitro cytotoxicity was conducted. Thermal stability, spectroscopy studies of the polymer, and preclinical studies of the coated bovine jugular vein in animals are in progress. The feasibility studies have been completed, and the final polymer selection depends on evaluation of the functional superiority of the coated bovine jugular vein.

  13. Modeling Reactive Transport in Coupled Groundwater-Conduit Systems

    Spiessl, S. M.; Sauter, M.; Zheng, C.; Viswanathan, H. S.

    2002-05-01

    Modeling reactive transport in coupled groundwater-conduit systems requires consideration of two transport time scales in the flow and transport models. Consider for example a subsurface mine consisting of a network of highly conductive shafts, drifts or ventilation raises (i.e., conduits) within the considerably less permeable ore material (i.e., matrix). In the conduits, potential contaminants can travel much more rapidly than in the background aquifer (matrix). Since conduits cannot necessarily be regarded as a continuum, double continuum models are only of limited use for simulation of contaminant transport in such coupled groundwater-conduit systems. This study utilizes a "hybrid" flow and transport model in which contaminants can in essence be transported at a slower time scale in the matrix and at a faster time scale in the conduits. The hybrid flow model uses an approach developed by Clemens et al. (1996), which is based on the modelling of flow in a discrete pipe network, coupled to a continuum representing the low-permeability inter-conduit matrix blocks. Laminar or turbulent flow can be simulated in the different pipes depending on the flow conditions in the model domain. The three-dimensional finite-difference groundwater flow model MODFLOW (Harbaugh and McDonald, 1996) is used to simulate flow in the continuum. Contaminant transport within the matrix is simulated with a continuum approach using the three-dimensional multi-species solute transport model MT3DMS (Zheng and Wang, 1999), while that in the conduit system is simulated with a one-dimensional advective transport model. As a first step for reactive transport modeling in such systems, only equilibrium reactions among multiple species are considered by coupling the hybrid transport model to a geochemical speciation package. An idealized mine network developed by Viswanathan and Sauter (2001) is used as a test problem in this study. The numerical experiment is based on reference date collected from

  14. Convective heat transfer of nanofluid flow through conduits with different cross-sectional shapes

    Salimpour, Mohammad Reza; Dehshiri-Parizi, Amir [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2015-02-15

    This study investigates the laminar forced convective heat transfer of TiO{sub 2}/water nanofluids through conduits with different cross sections, experimentally. The effects of different parameters, such as cross-sectional shape, Reynolds number, and concentration of nanoparticles, on the enhanced heat transfer are examined by designing and assembling an experimental apparatus. Results show that adding a small amount of nanoparticles to the base fluid improves heat transfer behavior in conduits. A conduit with a circular cross section performs better than conduits with square and triangular cross sections. However, conduits with square and triangular cross sections exhibit more relative enhancements than a conduit with a circular cross section.

  15. Design of barrier coatings on kink-resistant peripheral nerve conduits

    Basak Acan Clements

    2016-02-01

    Full Text Available Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1 electrospinning a layer of polymer fibers onto the surface of the conduit and (2 coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.

  16. Design of barrier coatings on kink-resistant peripheral nerve conduits.

    Clements, Basak Acan; Bushman, Jared; Murthy, N Sanjeeva; Ezra, Mindy; Pastore, Christopher M; Kohn, Joachim

    2016-01-01

    Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1) electrospinning a layer of polymer fibers onto the surface of the conduit and (2) coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.

  17. Monitoring of stage and velocity, for computation of discharge in the Summit Conduit near Summit, Illinois, 2010-2012

    Johnson, Kevin K.; Goodwin, Greg E.

    2013-01-01

    Lake Michigan diversion accounting is the process used by the U. S. Army Corps of Engineers to quantify the amount of water that is diverted from the Lake Michigan watershed into the Illinois and Mississippi River Basins. A network of streamgages within the Chicago area waterway system monitor tributary river flows and the major river flow on the Chicago Sanitary and Ship Canal near Lemont as one of the instrumental tools used for Lake Michigan diversion accounting. The mean annual discharges recorded by these streamgages are used as additions or deductions to the mean annual discharge recorded by the main stream gaging station currently used in the Lake Michigan diversion accounting process, which is the Chicago Sanitary and Ship Canal near Lemont, Illinois (station number 05536890). A new stream gaging station, Summit Conduit near Summit, Illinois (station number 414757087490401), was installed on September 23, 2010, for the purpose of monitoring stage, velocity, and discharge through the Summit Conduit for the U.S. Army Corps of Engineers in accordance with Lake Michigan diversion accounting. Summit Conduit conveys flow from a small part of the lower Des Plaines River watershed underneath the Des Plaines River directly into the Chicago Sanitary and Ship Canal. Because the Summit Conduit discharges into the Chicago Sanitary and Ship Canal upstream from the stream gaging station at Lemont, Illinois, but does not contain flow diverted from the Lake Michigan watershed, it is considered a flow deduction to the discharge measured by the Lemont stream gaging station in the Lake Michigan diversion accounting process. This report offers a technical summary of the techniques and methods used for the collection and computation of the stage, velocity, and discharge data at the Summit Conduit near Summit, Illinois stream gaging station for the 2011 and 2012 Water Years. The stream gaging station Summit Conduit near Summit, Illinois (station number 414757087490401) is an

  18. Combined physical and chemical nonequilibrium transport model for solution conduits.

    Field, Malcolm S; Leij, Feike J

    2014-02-01

    Solute transport in karst aquifers is primarily constrained to relatively complex and inaccessible solution conduits where transport is often rapid, turbulent, and at times constrictive. Breakthrough curves generated from tracer tests in solution conduits are typically positively-skewed with long tails evident. Physical nonequilibrium models to fit breakthrough curves for tracer tests in solution conduits are now routinely employed. Chemical nonequilibrium processes are likely important interactions, however. In addition to partitioning between different flow domains, there may also be equilibrium and nonequilibrium partitioning between the aqueous and solid phases. A combined physical and chemical nonequilibrium (PCNE) model was developed for an instantaneous release similar to that developed by Leij and Bradford (2009) for a pulse release. The PCNE model allows for partitioning open space in solution conduits into mobile and immobile flow regions with first-order mass transfer between the two regions to represent physical nonequilibrium in the conduit. Partitioning between the aqueous and solid phases proceeds either as an equilibrium process or as a first-order process and represents chemical nonequilibrium for both the mobile and immobile regions. Application of the model to three example breakthrough curves demonstrates the applicability of the combined physical and chemical nonequilibrium model to tracer tests conducted in karst aquifers, with exceptionally good model fits to the data. The three models, each from a different state in the United States, exhibit very different velocities, dispersions, and other transport properties with most of the transport occurring via the fraction of mobile water. Fitting the model suggests the potentially important interaction of physical and chemical nonequilibrium processes.

  19. Clinical use of nerve conduits in peripheral-nerve repair : Review of the literature

    Meek, MF; Coert, JH

    2002-01-01

    The use of nerve conduits has evolved from a previous experimental idea to a clinical reality over the last ten years. An overview of the literature on the clinical use of nerve conduits in peripheral-nerve repair is presented.

  20. Hemiresective reconstruction of a redundant ileal conduit with severe bilateral ileal conduit-ureteral re fl ux.

    Fujimura, Tetsuya; Minowada, Shigeru; Kishi, Hiroichi; Hamasaki, Kimihisa; Saito, Kiyoshi; Kitamura, Tadaichi

    2005-10-01

    A 58-year-old man was referred to our hospital with high fever and anuria. Since undergoing a total pelvic exenteration due to bladder-invasive sigmoid colon cancer, urinary tract infections had frequently occurred. We treated with the construction of a bilateral percutaneous nephrostomy (PCN), and chemotherapy. Although we replaced the PCN with a single J ureteral catheter after an improvement of infection, urinary infection recurred because of an obstruction of the catheter. Urological examinations showed that an ileal conduit-ureteral reflux caused by kinking of the ileal loop was the reason why frequent pyelonephritis occurred. We decided to resect the proximal segment to improve conduit-ureteral reflux for the resistant pyelonephritis. After the surgery, the excretory urogram showed improvement and the urinary retention at the ileal conduit disappeared. Three years after the operation, renal function has been stable without episodes of pyelonephritis. Here we report a case of open repair surgery of an ileal conduit in a patient with severe urinary infection.

  1. Exact solutions for unsteady unidirectional flows of a generalized second-order fluid through a rectangular conduit

    Kang, Jianhong; Xu, Mingyu

    2009-04-01

    The exact solutions are obtained for unsteady unidirectional flows of a generalized second-order fluid through a rectangular conduit. The fractional calculus in the constitutive relationship of a non-Newtonian fluid is introduced. We construct the solutions by means of Fourier transform and the discrete Laplace transform of the sequential derivatives and the double finite Fourier transform. The solutions for Newtonian fluid between two infinite parallel plates appear as limiting cases of our solutions.

  2. Exact solutions for unsteady unidirectional flows of a generalized second-order fluid through a rectangular conduit

    Jianhong Kang; Mingyu Xu

    2009-01-01

    The exact solutions are obtained for unsteady unidirectional flows of a generalized second-order fluid through a rectangular conduit. The fractional calculus in the constitutive relationship of a non-Newtonian fluid is introduced. We construct the solutions by means of Fourier transform and the discrete Laplace transform of the sequential derivatives and the double finite Fourier transform. The solutions for Newtonian fluid between two infinite parallel plates appear as limiting cases of our solutions.

  3. 30 CFR 75.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    2010-07-01

    ... conduits enclosing power conductors. 75.700 Section 75.700 Mineral Resources MINE SAFETY AND HEALTH... Grounding § 75.700 Grounding metallic sheaths, armors, and conduits enclosing power conductors. All metallic sheaths, armors, and conduits enclosing power conductors shall be electrically continuous throughout...

  4. 30 CFR 77.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

    2010-07-01

    ... conduits enclosing power conductors. 77.700 Section 77.700 Mineral Resources MINE SAFETY AND HEALTH..., and conduits enclosing power conductors. Metallic sheaths, armors, and conduits enclosing power conductors shall be electrically continuous throughout and shall be grounded by methods approved by...

  5. Stable and Reactive Centering in Conduits for Karstic Exploration

    2014-01-01

    International audience; Karst groundwaters provide fresh water resources to supply cities. In the case of deep groundwater resources around the Mediterranean basin there is a need to explore karst aquifers and gather data about their structure. Robots are well adapted for this task especially when exploring karst conduits at depths greater than 200m. However, as karst aquifers environment is very complex, robots need to exhibit a collection of abilities to ensure a safe exploration. Among the...

  6. Explosive device of conduit using Ti Ni alloy

    A. Yu. Kolobov

    2014-01-01

    Full Text Available Presently, materials have been developed which are capable at changing temperate to return significant inelastic deformations, exhibit rubber-like elasticity, convert heat into mechanical work, etc. The aggregate of these effects is usually called the shape memory effect.At present a great number of compounds and alloys with a shape memory effect has been known.These are alloys based on titanium nickelide (TiNi, copper-based alloys (Cu-Al, Cu-Sn, Cu-Al-Ni, Cu-Zn-Si, etc., gold and silver (Ag-Cd, Au-Ag-Cd, Au-Cd-Cu, Au-Zn-Cu, etc., manganese (Mn-Cr, Fe-Cu, Mn-Cu-Ni, Mn-Cu-Zr, Mn-Ni, etc., iron (Fe-Mn, Fe-Ni, Fe-Al, etc., and other compounds.The alloys based on titanium nickelide (nitinol are the most widely used.Alloys with shape memory effect find various applications in engineering and medicine, namely connecting devices, actuators, transformable design, multipurpose medical implants, etc.There is a task of breaking fuel conduit during separating the spacecraft from the rocket in space technology.The paper examines the procedure for design calculation of the separating device of conduit with the use of Ti-Ni alloy. This device can be used instead of the pyro-knives.The device contains two semi-rings from Ti-Ni alloy. In the place of break on the conduit an annular radius groove is made.At a temperature of martensite passage the semi-rings undergo deformation and in the strained state are set in the device. With heating to the temperature of the austenitic passage of bushing macro-deformation the energy stored by the nitinol bushing is great enough to break the conduit on the neck.The procedures of design calculation and response time of device are given.

  7. Free-boundary models of a meltwater conduit

    Dallaston, Michael C.

    2014-08-01

    © 2014 AIP Publishing LLC. We analyse the cross-sectional evolution of an englacial meltwater conduit that contracts due to inward creep of the surrounding ice and expands due to melting. Making use of theoretical methods from free-boundary problems in Stokes flow and Hele-Shaw squeeze flow we construct an exact solution to the coupled problem of external viscous creep and internal heating, in which we adopt a Newtonian approximation for ice flow and an idealized uniform heat source in the conduit. This problem provides an interesting variant on standard free-boundary problems, coupling different internal and external problems through the kinematic condition at the interface. The boundary in the exact solution takes the form of an ellipse that may contract or expand (depending on the magnitudes of effective pressure and heating rate) around fixed focal points. Linear stability analysis reveals that without the melting this solution is unstable to perturbations in the shape. Melting can stabilize the interface unless the aspect ratio is too small; in that case, instabilities grow largest at the thin ends of the ellipse. The predictions are corroborated with numerical solutions using boundary integral techniques. Finally, a number of extensions to the idealized model are considered, showing that a contracting circular conduit is unstable to all modes of perturbation if melting occurs at a uniform rate around the boundary, or if the ice is modelled as a shear-thinning fluid.

  8. Peripheral nerve regeneration with conduits: use of vein tubes

    Rodrigo Guerra Sabongi

    2015-01-01

    Full Text Available Treatment of peripheral nerve injuries remains a challenge to modern medicine due to the complexity of the neurobiological nerve regenerating process. There is a greater challenge when the transected nerve ends are not amenable to primary end-to-end tensionless neurorraphy. When facing a segmental nerve defect, great effort has been made to develop an alternative to the autologous nerve graft in order to circumvent morbidity at donor site, such as neuroma formation, scarring and permanent loss of function. Tubolization techniques have been developed to bridge nerve gaps and have been extensively studied in numerous experimental and clinical trials. The use of a conduit intends to act as a vehicle for moderation and modulation of the cellular and molecular ambience for nerve regeneration. Among several conduits, vein tubes were validated for clinical application with improving outcomes over the years. This article aims to address the investigation and treatment of segmental nerve injury and draw the current panorama on the use of vein tubes as an autogenous nerve conduit.

  9. Inferring conduit process from population studies of cinder cone craters

    Bemis, Karen G.

    2014-05-01

    One of the most observable aspects of magma conduits is of course their exit to the Earth's surface: the volcanic crater. The craters resulting from small mostly-monogenetic volcanic eruptions vary in considerable in size and shape, even after accounting for variation in size. Presumably, these variations tell us something about the state of the conduit at least in the ending stages of eruption. But what? This work explores the statistical properties of crater populations in Guatemala and elsewhere and speculates on the conduit processes that may explain the complex behavior. Crater depths are strongly correlated with cone slopes even when normalized by cone diameter, which suggests the importance of the impact of the volatile content (which may influence slope through fragmentation and the resulting grain size) and the duration of eruption (which may influence whether the cone is built to its maximum slope) despite erosion acting to reduce observed crater depths (cone slopes are known to decrease with erosion but cone diameters increase).

  10. Tracking dynamics of magma migration in open-conduit systems

    Valade, Sébastien; Lacanna, Giorgio; Coppola, Diego; Laiolo, Marco; Pistolesi, Marco; Donne, Dario Delle; Genco, Riccardo; Marchetti, Emanuele; Ulivieri, Giacomo; Allocca, Carmine; Cigolini, Corrado; Nishimura, Takeshi; Poggi, Pasquale; Ripepe, Maurizio

    2016-11-01

    Open-conduit volcanic systems are typically characterized by unsealed volcanic conduits feeding permanent or quasi-permanent volcanic activity. This persistent activity limits our ability to read changes in the monitored parameters, making the assessment of possible eruptive crises more difficult. We show how an integrated approach to monitoring can solve this problem, opening a new way to data interpretation. The increasing rate of explosive transients, tremor amplitude, thermal emissions of ejected tephra, and rise of the very-long-period (VLP) seismic source towards the surface are interpreted as indicating an upward migration of the magma column in response to an increased magma input rate. During the 2014 flank eruption of Stromboli, this magma input preceded the effusive eruption by several months. When the new lateral effusive vent opened on the Sciara del Fuoco slope, the effusion was accompanied by a large ground deflation, a deepening of the VLP seismic source, and the cessation of summit explosive activity. Such observations suggest the drainage of a superficial magma reservoir confined between the crater terrace and the effusive vent. We show how this model successfully reproduces the measured rate of effusion, the observed rate of ground deflation, and the deepening of the VLP seismic source. This study also demonstrates the ability of the geophysical network to detect superficial magma recharge within an open-conduit system and to track magma drainage during the effusive crisis, with a great impact on hazard assessment.

  11. Useful life extension of steam-turbine elements by means of welding processes; Extension de la vida util de los elementos de las turbinas de vapor mediante procesos de soldadura

    Mazur Czerwiec, Zdzislaw; Cristalinas Navarro, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1994-03-01

    The elements of the flow system in the steam turbines are subjected to a natural or accelerated wear during their operation. The stationary and the rotating blades are parts of the turbine that present damages, faults or materials wear, after some service periods, that can be from mechanical or metallurgical origin and prevent its continuous operation. This is also revealed in the equipment availability, reliability and performance diminution. Several cases are presented of recovery, and useful life extension of worn stationary blades (nozzle blocks and diaphragms), and rotating blades by means of welding processes executed in several fossil fuel power plants of Comision Federal de Electricidad. For each specific case, wear type or damage, the special processes based in welding processes, were developed. The blade recovery process also includes: the stress relieving, machining, special coating, quality control and tool design. Once the recovery process is completed, the components were installed back in the turbines for their utilization. The application of the welding technologies developed for blade recovery, represents just a fraction of the cost of new blades, that results in an economic saving. [Espanol] Los elementos del sistema de flujo de las turbinas de vapor sufren un desgaste natural o acelerado durante su operacion. Los alabes fijos y moviles son las partes de la turbina que despues de ciertos periodos de servicio presentan danos, fallas o desgaste del material que pueden ser de origen mecanico o metalurgico y no permiten su operacion continua. Esto se refleja tambien en la disminucion de la disponibilidad, confiabilidad y rendimiento del equipo. Se presentan varios casos de recuperacion y prolongacion de la vida util de alabes fijos (bloques de toberas y diafragmas) y moviles danados y gastados a causa de procesos de soldadura que se llevaron a cabo en varias plantas termoelectricas de la Comision Federal de Electricidad. Para cada caso especifico

  12. Simulation of particle motion in a closed conduit validated against experimental data

    Dolanský Jindřich

    2015-01-01

    Full Text Available Motion of a number of spherical particles in a closed conduit is examined by means of both simulation and experiment. The bed of the conduit is covered by stationary spherical particles of the size of the moving particles. The flow is driven by experimentally measured velocity profiles which are inputs of the simulation. Altering input velocity profiles generates various trajectory patterns. The lattice Boltzmann method (LBM based simulation is developed to study mutual interactions of the flow and the particles. The simulation enables to model both the particle motion and the fluid flow. The entropic LBM is employed to deal with the flow characterized by the high Reynolds number. The entropic modification of the LBM along with the enhanced refinement of the lattice grid yield an increase in demands on computational resources. Due to the inherently parallel nature of the LBM it can be handled by employing the Parallel Computing Toolbox (MATLAB and other transformations enabling usage of the CUDA GPU computing technology. The trajectories of the particles determined within the LBM simulation are validated against data gained from the experiments. The compatibility of the simulation results with the outputs of experimental measurements is evaluated. The accuracy of the applied approach is assessed and stability and efficiency of the simulation is also considered.

  13. The Malone Antegrade Continence Enema (MACE principle in children: is it important if the conduit is implanted in the left or the right colon?

    Karine F. Meyer

    2008-03-01

    Full Text Available OBJECTIVE: The aim of the study was to determine which was the optimal side for the conduit to be placed (right or left colon for antegrade continence enema implantation. MATERIALS AND METHODS: Between July 1999 and March 2006, 31 patients underwent the construction of a catheterizable conduit using the Malone principle (MACE In 22 cases the conduit was re-implanted in the right colon and in 9 cases in the left colon. There were 20 male patients and 11 female patients, with a mean age of 10.23 years. The follow-up period varied from 3 from 83 months (average 25 months. Right and left implantation of the conduit in the colon were compared with regards to the presence of complications, volume of the solution utilized, frequency of colonic lavage, time needed for performing the enema, and degree of satisfaction. RESULTS: One patient with the conduit in the right colon, using the appendix, lost the mechanism after two month follow-up. Thirty patients remain clean and are all capable of performing self-catheterization. No statistically significant differences were found between the groups regarding the variables studied: complications (p = 1.000, solution volume (p = 0.996, time required (p = 0.790 and patient's rating (p = 0.670. The lavage frequency required for patients with the conduit in the right colon may be lower. CONCLUSION: The MACE principle was considered effective for treating fecal retention and leaks, independent of the implantation site. The success of this surgery appears to be directly related to the patient's motivation and not to the technique utilized.

  14. Tensile and fatigue qualification testing of ITER-CS conduit alloy JK2LB

    Walsh, R. P.; McRae, D. M.; Han, K.; Martovetsky, N. N.

    2015-12-01

    The ITER Central Solenoid (CS) coils utilize cable-in-conduit conductor (CICC) and the conduit alloy is JK2LB. The production grade conduit alloy (and it's welds) must meet strict requirements for strength, toughness, fatigue crack resistance, and fabricability. The conduit alloy must retain good mechanical properties after additional fabrication steps such as welding, coil winding strain and exposure to the Nb3Sn superconductor's reaction heat treatment. Here we present data from cryogenic tensile, fracture toughness, fatigue crack growth rate, and axial fatigue tests of JK2LB alloy and conduit butt welds, before and after the exposure to the reaction heat treatment. The tests of specimens removed directly from the conduit provide confirmation of the materials properties and the effect of the cold work and aging. The 4 K fatigue performance is extremely important to the reliability of the CS and is covered both by axial cyclic fatigue tests and the fatigue crack growth rate measurements.

  15. In vivo adaptive response of the peripheral conduit artery in patients with borderline systolic hypertension

    陶军; 靳亚非; 王礼春; 唐安丽; 廖新学; 杨震; 马虹

    2003-01-01

    Objective To investigate elastic changes of the radial artery, a medium-sized muscular peripheral conduit artery, in patients with borderline systolic hypertension. Methods Using a non-invasive high-resolution echo-tracking device coupled to a photoplethysmography (Finapres system) allowing simultaneous arterial diameter and finger blood pressure monitoring, we measured radial artery elastic parameters of 20 patients with borderline systolic hypertension and 20 normal subjects according to Langewouters model.Results The diameter of the radial artery of control subjects and those with borderline systolic hypertension at the isobaric level of 100 mmHg and mean arterial pressure was similar, but the compliance and distensibility at similar conditions in patients with borderline systolic hypertension did not further reduced and even increased. Conclusion In patients with borderline systolic hypertension, the adaptive responses of the radial artery compliance and distensibility to increased pressure were directed to maintain its elasticity, contributing to the homeostasis of the cardiovascular system.

  16. Study on Braiding Parameters of a Biodegradable Nerve Regeneration Conduit with Regular Braided Structure

    LIU Guo-hua; ZHANG Pei-hua; WANG Wen-zu; FENG Xun-wei; LIU Hong-feng

    2004-01-01

    A biodegradable nerve regeneration conduit has been developed by the regular braided technique on a spindle-braiding machine. The geometry property indexes of braided nerve conduit consist of pitch, density, wall thickness and porosity etc. In this article, the influences of the braiding parameters i.e. the linear density of yarn, gear ratio and spindle number of the braiding machine on these geometry property indexes of nerve conduit were discussed from which the optimal braiding parameters were obtained.

  17. Enhancing Peripheral Nerve Regeneration with a Novel Drug Delivering Nerve Conduit

    2014-10-01

    Products 21 7. Participants & Other Collaborating Organizations 22 8. Special Reporting Requirements 23 9. Appendices 24 3... Corning Inc) were also added to the nerve conduit. Figure 2 illustrates the nerve conduit in which the drug (NGF) stored in the orifice between...7525 DLG 7E, Evonik). The PLGA was dissolved in acetone and ethanol and conduits were then formed and emulsified in water. 15µm diffusion holes

  18. 3D-engineering of Cellularized Conduits for Peripheral Nerve Regeneration

    Hu, Yu; Wu, Yao; Gou, Zhiyuan; Tao, Jie; Zhang, Jiumeng; Liu, Qianqi; Kang, Tianyi; Jiang, Shu; Huang, Siqing; He, Jiankang; Chen, Shaochen; Du, Yanan; Gou, Maling

    2016-08-01

    Tissue engineered conduits have great promise for bridging peripheral nerve defects by providing physical guiding and biological cues. A flexible method for integrating support cells into a conduit with desired architectures is wanted. Here, a 3D-printing technology is adopted to prepare a bio-conduit with designer structures for peripheral nerve regeneration. This bio-conduit is consisted of a cryopolymerized gelatin methacryloyl (cryoGelMA) gel cellularized with adipose-derived stem cells (ASCs). By modeling using 3D-printed “lock and key” moulds, the cryoGelMA gel is structured into conduits with different geometries, such as the designed multichannel or bifurcating and the personalized structures. The cryoGelMA conduit is degradable and could be completely degraded in 2-4 months in vivo. The cryoGelMA scaffold supports the attachment, proliferation and survival of the seeded ASCs, and up-regulates the expression of their neurotrophic factors mRNA in vitro. After implanted in a rat model, the bio-conduit is capable of supporting the re-innervation across a 10 mm sciatic nerve gap, with results close to that of the autografts in terms of functional and histological assessments. The study describes an indirect 3D-printing technology for fabricating cellularized designer conduits for peripheral nerve regeneration, and could lead to the development of future nerve bio-conduits for clinical use.

  19. Environmental tracers as indicators of karst conduits in groundwater in South Dakota, USA

    Long, A.J.; Sawyer, J.F.; Putnam, L.D.

    2008-01-01

    Environmental tracers sampled from the carbonate Madison aquifer on the eastern flank of the Black Hills, South Dakota, USA indicated the approximate locations of four major karst conduits. Contamination issues are a major concern because these conduits are characterized by direct connections to sinking streams, high groundwater velocities, and proximity to public water supplies. Objectives of the study were to estimate approximate conduit locations and assess possible anthropogenic influences associated with conduits. Anomalies of young groundwater based on chlorofluorocarbons (CFCs), tritium, and electrical conductivity (EC) indicated fast moving, focused flow and thus the likely presence of conduits. ??18O was useful for determining sources of recharge for each conduit, and nitrate was a useful tracer for assessing flow paths for anthropogenic influences. Two of the four conduits terminate at or near a large spring complex. CFC apparent ages ranged from 15 years near conduits to >50 years in other areas. Nitrate-N concentrations >0.4 mg/L in groundwater were associated with each of the four conduits compared with concentrations ranging from <0.1 to 0.4 mg/L in other areas. These higher nitrate-N concentrations probably do not result from sinking streams but rather from other areas of infiltration. ?? Springer-Verlag 2007.

  20. 3D-engineering of Cellularized Conduits for Peripheral Nerve Regeneration

    Hu, Yu; Wu, Yao; Gou, Zhiyuan; Tao, Jie; Zhang, Jiumeng; Liu, Qianqi; Kang, Tianyi; Jiang, Shu; Huang, Siqing; He, Jiankang; Chen, Shaochen; Du, Yanan; Gou, Maling

    2016-01-01

    Tissue engineered conduits have great promise for bridging peripheral nerve defects by providing physical guiding and biological cues. A flexible method for integrating support cells into a conduit with desired architectures is wanted. Here, a 3D-printing technology is adopted to prepare a bio-conduit with designer structures for peripheral nerve regeneration. This bio-conduit is consisted of a cryopolymerized gelatin methacryloyl (cryoGelMA) gel cellularized with adipose-derived stem cells (ASCs). By modeling using 3D-printed “lock and key” moulds, the cryoGelMA gel is structured into conduits with different geometries, such as the designed multichannel or bifurcating and the personalized structures. The cryoGelMA conduit is degradable and could be completely degraded in 2-4 months in vivo. The cryoGelMA scaffold supports the attachment, proliferation and survival of the seeded ASCs, and up-regulates the expression of their neurotrophic factors mRNA in vitro. After implanted in a rat model, the bio-conduit is capable of supporting the re-innervation across a 10 mm sciatic nerve gap, with results close to that of the autografts in terms of functional and histological assessments. The study describes an indirect 3D-printing technology for fabricating cellularized designer conduits for peripheral nerve regeneration, and could lead to the development of future nerve bio-conduits for clinical use. PMID:27572698

  1. Development of a new lacrimal drainage conduit using POSS nanocomposite.

    Chaloupka, Karla; Motwani, Meghna; Seifalian, Alexander Marcus

    2011-01-01

    Lacrimal surgery in cases of severely obstructed or missing canalicular ducts is highly challenging. In these cases, the placement of a bypass tube is currently the only option to restore the drainage of tears into the nose and reduce the symptomatic watery eye. Different approaches to achieve functional drainage have been tried using blood vessels or artificial implants. The implantation of the rigid Lester Jones tube is, since its introduction in the late 1960s, the gold standard. The functional success is satisfactory. However, complication rates are high and remain, even with many modifications of the original design, a major problem. These complications include mainly the displacement and blockage of the tube, requiring regular checkups, as well as irritation of the surrounding tissue including the nose and the eye. The objective of this study was to develop a new lacrimal duct conduit (LDC) to restore structural and functional integrity of the lacrimal drainage system. The conduit is constructed with a novel polymer, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU), that offers biocompatibility. We exploit nanotopography to evade the problems associated with current applications. A number of extrusion techniques were investigated for this purpose: ultrasonic atomization spraying, electrohydrodynamic atomization spraying/spinning, extrusion-coagulation, and high-pressure coagulation by autoclave and casting. Finally, the coagulation and cast technique were selected to construct an LDC superior to its predecessors, and its advantages highlighted.

  2. Conduit for high temperature transfer of molten semiconductor crystalline material

    Fiegl, George (Inventor); Torbet, Walter (Inventor)

    1983-01-01

    A conduit for high temperature transfer of molten semiconductor crystalline material consists of a composite structure incorporating a quartz transfer tube as the innermost member, with an outer thermally insulating layer designed to serve the dual purposes of minimizing heat losses from the quartz tube and maintaining mechanical strength and rigidity of the conduit at the elevated temperatures encountered. The composite structure ensures that the molten semiconductor material only comes in contact with a material (quartz) with which it is compatible, while the outer layer structure reinforces the quartz tube, which becomes somewhat soft at molten semiconductor temperatures. To further aid in preventing cooling of the molten semiconductor, a distributed, electric resistance heater is in contact with the surface of the quartz tube over most of its length. The quartz tube has short end portions which extend through the surface of the semiconductor melt and which are lef bare of the thermal insulation. The heater is designed to provide an increased heat input per unit area in the region adjacent these end portions.

  3. Temperature control of a steam generator by means of an hybrid system PID-RLC; Control de las temperaturas de un generador de vapor mediante un sistema hibrido PID-RLC

    Palomares Gonzalez, Daniel; Garcia Mendoza, Raul [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    A description is made of the design and evaluation of an hybrid control system, formed by a quadratic gaussian linear regulator (QLR) and proportional integral derivative (PID) type regulators. This scheme is used to control the reheater and secondary superheater steam temperatures of a steam generator model with a maximum capacity of 2,150,000 pounds per hour. Once applied to the model of a 300 MW steam power plant, this system showed better results than the traditional schemes and inclusively better than some modern control schemes. This fact characterizes it as a high potential system to be applied to steam power plants. [Espanol] Se describe el diseno y la evaluacion de un sistema de control hibrido, formado por un regulador lineal cuadratico gaussiano (RLC) y reguladores tipo proporcional integral derivativo (PID). Este esquema se utiliza para controlar las temperaturas de vapor del recalentador y sobrecalentador secundario del modelo de un generador de vapor con capacidad maxima de 2,150,000 libras por hora. Una vez aplicado al modelo de una unidad termoelectrica de 300 MW, este sistema produjo mejores resultados que los esquemas tradicionales e incluso mejores que algunos esquemas de control moderno. Esto lo caracteriza como un sistema con un alto potencial para aplicarse a unidades termoelectricas.

  4. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration

    Widmer, M. S.; Gupta, P. K.; Lu, L.; Meszlenyi, R. K.; Evans, G. R.; Brandt, K.; Savel, T.; Gurlek, A.; Patrick, C. W. Jr; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  5. Silicic magma differentiation in ascent conduits. Experimental constraints

    Rodríguez, Carmen; Castro, Antonio

    2017-02-01

    Crystallization of water-bearing silicic magmas in a dynamic thermal boundary layer is reproduced experimentally by using the intrinsic thermal gradient of piston-cylinder assemblies. The standard AGV2 andesite under water-undersaturated conditions is set to crystallize in a dynamic thermal gradient of about 35 °C/mm in 10 mm length capsules. In the hotter area of the capsule, the temperature is initially set at 1200 °C and decreases by programmed cooling at two distinct rates of 0.6 and 9.6 °C/h. Experiments are conducted in horizontally arranged assemblies in a piston cylinder apparatus to avoid any effect of gravity settling and compaction of crystals in long duration runs. The results are conclusive about the effect of water-rich fluids that are expelled out the crystal-rich zone (mush), where water saturation is reached by second boiling in the interstitial liquid. Expelled fluids migrate to the magma ahead of the solidification front contributing to a progressive enrichment in the fluxed components SiO2, K2O and H2O. The composition of water-rich fluids is modelled by mass balance using the chemical composition of glasses (quenched melt). The results are the basis for a model of granite magma differentiation in thermally-zoned conduits with application of in-situ crystallization equations. The intriguing textural and compositional features of the typical autoliths, accompanying granodiorite-tonalite batholiths, can be explained following the results of this study, by critical phenomena leading to splitting of an initially homogeneous magma into two magma systems with sharp boundaries. Magma splitting in thermal boundary layers, formed at the margins of ascent conduits, may operate for several km distances during magma transport from deep sources at the lower crust or upper mantle. Accordingly, conduits may work as chromatographic columns contributing to increase the silica content of ascending magmas and, at the same time, leave behind residual mushes that

  6. A polylactic acid non-woven nerve conduit for facial nerve regeneration in rats.

    Matsumine, Hajime; Sasaki, Ryo; Yamato, Masayuki; Okano, Teruo; Sakurai, Hiroyuki

    2014-06-01

    This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean ± SD, 5051 ± 2335), followed by autologous nerves (4233 ± 590) and silicone tubes (1604 ± 148). Axon diameter was significantly greater in the PLA tube group (5.17 ± 1.69 µm) than in the silicone tube group (4.25 ± 1.60 µm) and no significant difference was found between the PLA tube and autograft (5.53 ± 1.93 µm) groups. Myelin thickness was greatest for the autograft group (0.65 ± 0.24 µm), followed by the PLA tube (0.54 ± 0.18 µm) and silicone tube (0.38 ± 0.12 µm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation.

  7. The Role of Oxygen Partial Pressure in Controlling the Phase Composition of La1- x Sr x Co y Fe1- y O3- δ Oxygen Transport Membranes Manufactured by Means of Plasma Spray-Physical Vapor Deposition

    Marcano, D.; Mauer, G.; Sohn, Y. J.; Vaßen, R.; Garcia-Fayos, J.; Serra, J. M.

    2016-04-01

    La0.58Sr0.4Co0.2Fe0.8O3 - δ (LSCF) deposited on a metallic porous support by plasma spray-physical vapor deposition is a promising candidate for oxygen-permeation membranes. Ionic transport properties are regarded to depend on the fraction of perovskite phase present in the membrane. However, during processing, the LSCF powder decomposes into perovskite and secondary phases. In order to improve the ionic transport properties of the membranes, spraying was carried out at different oxygen partial pressures p(O2). It was found that coatings deposited at lower and higher oxygen partial pressures consist of 70% cubic/26% rhombohedral and 61% cubic/35% rhombohedral perovskite phases, respectively. During annealing, the formation of non-perovskite phases is driven by oxygen non-stoichiometry. The amount of oxygen added during spraying can be used to increase the perovskite phase fraction and suppress the formation of non-perovskite phases.

  8. Injunctions against mere conduit of information protected by copyright

    Sandfeld Jakobsen, Søren; Petersen, Clement Salung

    2011-01-01

    requires rules, which take into due consideration the special aspects related to enforcement of copyright on the internet through IAPs. Secondly, it is shown that the termination of internet connections and the blocking of access to internet content may not support the public policies behind copyright law......This paper includes an in-depth analysis of EU law and Scandinavian law on injunctions against internet access providers (IAPs) performing as mere conduit of information protected by copyright. In recent Scandinavian case law, courts have granted preliminary injunctions which have caused IAPs...... to either shut down specific internet connections allegedly used to infringe copyright or to block access to internet content, which allegedly infringed applicable copyright rules. This paper considers some significant legal challenges, which are emerging in the wake of this case law, and which should...

  9. Experimental investigations of aeration efficiency in high-head gated circular conduits.

    Cihat Tuna, M; Ozkan, Fahri; Baylar, Ahmet

    2014-01-01

    The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes.

  10. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  11. Large-scale tests of insulated conduit for the ITER CS coil

    Reed, R. P.; Walsh, R. P.; Schutz, J. B.

    Compression-fatigue tests at 77 K were conducted on test modules of insulated Incoloy 908 conduit. To replicate the operating conditions for the ITER central solenoid (CS) full-scale coil, fatigue loads up to 3.6 MN were applied for 10 5 cycles; no mechanical breakdowns occurred. The conduits were insulated with a preimpregnated resin system, a tetraglycidyl diaminodiphenyl methane (TGDM) epoxy cured with DDS aromatic amine. The conduits were joined by vacuum-pressure impregnation with a diglycidyl ether of bisphenol-F epoxy/anhydride-cured resin system. In the 4×4 stacked-conduit test modules, the layer insulation (a high-pressure laminate of TGDM epoxy cured with DDS aromatic amine) was inserted. Periodically during the tests, breakdown voltage was measured across the conduits of both turn and layer insulation; throughout the test, breakdown voltages were at least 46 kV. The addition of a barrier increased structural and electrical reliability.

  12. Numerical Simulation of the Stress and Distortion of the Fiberglass-Reinforced Plastics Crust-Stainless Steel Liner Compound Conduit

    Hongyuan FANG; Chenglei FAN; Jianguo YANG; Ming LI; Zhen LUO; Xianzhong HOU

    2003-01-01

    A new type of compound conduit is designed and the finite element method (FEM) is applied to analyze the mechanicalperformance of a typical compound conduit. The results of the numerical simulation confirm that the distributionsof the strain

  13. Magnetic losses and reactance change by the use of metallic conduit in electrical installations; Perdidas magneticas y cambio de reactancia por la tuberia metalica en instalaciones electricas

    Campero Littlewood, Eduardo; Castaneda D, Miguel; Castulo A, Roberto; Bratu Serban, Neagu [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D. F. (Mexico)

    1996-12-31

    In this paper are presented the results obtained in the measurement of magnetic losses in metallic conduits in electric installations. The losses for parasitic currents and by hysteresis were obtained in different conditions of magnetic density, caused by the net current resulting from the sum of all the currents of all the conductors that travel along the conduit. These currents are named differential currents, and the conditions in which they appear in the electric installations are described. The magnetic induction phenomenon that occurs in metallic conduit is briefly described and the basic concepts that describe it. A theoretical-experimental methodology is offered to quantify the energy losses by parasitic currents and by the metal magnetization in these metallic conduits. At the same time, the impact of these differential currents impact in the reactance of the electric installation is quantified. The obtained results for twelve conduits of different diameters and different wall thickness are shown. A comparison analysis is made with the reported results in a previous article, where the losses were estimated by means of the temperature rise measurement of the metallic wall. [Espanol] En este articulo se presentan los resultados obtenidos en la medicion de perdidas magneticas en tuberias conduit (metalicas) en instalaciones electricas. Las perdidas por corrientes parasitas y por histeresis se obtuvieron para diferentes condiciones de densidad magnetica, provocada por la corriente neta resultante de la suma de las corrientes de todos los conductores que viajan por la tuberia. A estas corrientes se les designa corrientes diferenciales y se describen las condiciones en las que estas aparecen en las instalaciones electricas. Se explica brevemente el fenomeno de induccion magnetica que se presenta en las tuberias metalicas y los conceptos basicos que la describen. Se plantea una metodologia teorico-experiemental para cuantificar las perdidas de energia, por

  14. Engineering a multimodal nerve conduit for repair of injured peripheral nerve

    Quigley, A. F.; Bulluss, K. J.; Kyratzis, I. L. B.; Gilmore, K.; Mysore, T.; Schirmer, K. S. U.; Kennedy, E. L.; O'Shea, M.; Truong, Y. B.; Edwards, S. L.; Peeters, G.; Herwig, P.; Razal, J. M.; Campbell, T. E.; Lowes, K. N.; Higgins, M. J.; Moulton, S. E.; Murphy, M. A.; Cook, M. J.; Clark, G. M.; Wallace, G. G.; Kapsa, R. M. I.

    2013-02-01

    Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate

  15. Archimedes Mass Filter Vaporizer

    Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

    2001-10-01

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

  16. Imaging mud fluid conduits of the Gunshuiping mud volcano with Electric Resistivity Methods

    Liao, Ling-Rong; Lin, Ting-Li; Chang, Ping-Yu

    2016-04-01

    We conducted the resistivity survey at the Gunshuiping mud volcano and produced a 3D model in order to delineate the mud-fluid conduits in the mud volcano system. The Gunshuiping mud volcano is located in a 175-m × 90-m plateau in Southwest of Taiwan. There are three main mud-volcano craters: craters 1, 2 and 3. Crater 3 is active and the others are inactive. We conducted thirteen survey lines using the Wenner configuration to obtain the resistivity profile images. The lengths of the lines are about 155 m and 60 m, which can resolve the resistivity image down to 30 m and 10 m in depth, respectively. The results appeared that there is a vertical structure under the crater 3, and we suggest that it is the mud-fluid conduit. There is a chamber at depth between 3 and 14 m, and we interpret it is the temporary storage of mud fluid during the erupting process. Beneath the craters 1 and 2, there is a near-surface, horizontal conduit connecting the craters 1 and 2. At depth between 15 and 25 m, the vertical conduit beneath the crater 3 and the horizontal conduit beneath the craters 1 and 2 are connected. The resistivity images clearly delineate the conduit underneath the craters and suggest that the crater 3 is the main erupting conduit, which is consistent with the surface features, in the Gunshuiping mud volcano system.

  17. Poly(lactic-co-glycolic acid) conduit for repair of injured sciatic nerve: A mechanical analysis.

    Yu, Tao; Zhao, Changfu; Li, Peng; Liu, Guangyao; Luo, Min

    2013-07-25

    Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic nerve injury. This study collected the sciatic nerve from the gluteus maximus muscle from fresh human cadaver, and established 10-mm-long sciatic nerve injury models by removing the ischium, following which poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts were transplanted. Scanning electron microscopy revealed that the axon and myelin sheath were torn, and the vessels of basilar membrane were obstructed in the poly(lactic-co-glycolic acid) conduit-repaired sciatic nerve following tensile testing. There were no significant differences in tensile tests with autogenous nerve graft-repaired sciatic nerve. Following poly(lactic-co-glycolic acid) conduit transplantation for sciatic nerve repair, tensile test results suggest that maximum tensile load, maximum stress, elastic limit load and elastic limit stress increased compared with autogenous nerve grafts, but elastic limit strain and maximum strain decreased. Moreover, the tendencies of stress-strain curves of sciatic nerves were similar after transplantation of poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts. Results showed that after transplantation in vitro for sciatic nerve injury, poly(lactic-co-glycolic acid) conduits exhibited good intensity, elasticity and plasticity, indicating that poly(lactic-co-glycolic acid) conduits are suitable for sciatic nerve injury repair.

  18. Modeling the closure of volcanic conduits with an application to Mount Vesuvius

    Quareni, Francesca; Mulargia, Francesco

    1993-03-01

    The eruptive activity of a volcano is controlled by the opening and closure of conduits through which magma ascends to the surface. We develop a model to study the deformation of a cylindrical conduit surrounded by a viscoelastic cylindrical region in an infinite, elastic, homogeneous space. The viscoelastic behavior of the zone around the conduit is due to heat conduction from the hot magma, which raises the temperature beyond the brittle-ductile transition point. The effect of a tectonic regional stress which favors (compressive) or acts against (tensile) conduit closure is taken into account. Conduit closure is found to be ruled essentially by the extension of the viscoelastic region and by the ratio between its rigidity and the rigidity of the surrounding elastic medium, while tectonic stress is much less important. The model is applied to the last eruptive cycle of Mount Vesuvius. We find that an open conduit condition has been possible from 1631 to 1944, while the quiescence from 1944 on implies a closed conduit state.

  19. Lunar absorption spectrophotometer for measuring atmospheric water vapor.

    Querel, Richard R; Naylor, David A

    2011-02-01

    A novel instrument has been designed to measure the nighttime atmospheric water vapor column abundance by near-infrared absorption spectrophotometry of the Moon. The instrument provides a simple, effective, portable, and inexpensive means of rapidly measuring the water vapor content along the lunar line of sight. Moreover, the instrument is relatively insensitive to the atmospheric model used and, thus, serves to provide an independent calibration for other measures of precipitable water vapor from both ground- and space-based platforms.

  20. Structure of a bacterial cell surface decaheme electron conduit.

    Clarke, Thomas A; Edwards, Marcus J; Gates, Andrew J; Hall, Andrea; White, Gaye F; Bradley, Justin; Reardon, Catherine L; Shi, Liang; Beliaev, Alexander S; Marshall, Matthew J; Wang, Zheming; Watmough, Nicholas J; Fredrickson, James K; Zachara, John M; Butt, Julea N; Richardson, David J

    2011-06-07

    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or participating in extracellular intercytochrome electron exchange along "nanowire" appendages. We present a 3.2-Å crystal structure of one of these decaheme cytochromes, MtrF, that allows the spatial organization of the 10 hemes to be visualized for the first time. The hemes are organized across four domains in a unique crossed conformation, in which a staggered 65-Å octaheme chain transects the length of the protein and is bisected by a planar 45-Å tetraheme chain that connects two extended Greek key split β-barrel domains. The structure provides molecular insight into how reduction of insoluble substrate (e.g., minerals), soluble substrates (e.g., flavins), and cytochrome redox partners might be possible in tandem at different termini of a trifurcated electron transport chain on the cell surface.

  1. Mapping the Hawaiian plume conduit with converted seismic waves

    Li; Kind; Priestley; Sobolev; Tilmann; Yuan; Weber

    2000-06-22

    The volcanic edifice of the Hawaiian islands and seamounts, as well as the surrounding area of shallow sea floor known as the Hawaiian swell, are believed to result from the passage of the oceanic lithosphere over a mantle hotspot. Although geochemical and gravity observations indicate the existence of a mantle thermal plume beneath Hawaii, no direct seismic evidence for such a plume in the upper mantle has yet been found. Here we present an analysis of compressional-to-shear (P-to-S) converted seismic phases, recorded on seismograph stations on the Hawaiian islands, that indicate a zone of very low shear-wave velocity (effects of the Hawaiian plume conduit in the asthenosphere and mantle transition zone with excess temperature of approximately 300 degrees C. Large variations in the transition-zone thickness suggest a lower-mantle origin of the Hawaiian plume similar to the Iceland plume, but our results indicate a 100 degrees C higher temperature for the Hawaiian plume.

  2. AMTEC vapor-vapor series connected cells

    Underwood, Mark L.; Williams, Roger M.; Ryan, Margaret A.; Nakamura, Barbara J.; Oconnor, Dennis E.

    1995-08-01

    An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

  3. Vapor Control Layer Recommendations

    None

    2009-09-08

    This information sheet describes the level of vapor control required on the interior side of framed walls with typical fibrous cavity insulation (fibreglass, rockwool, or cellulose, based on DOE climate zone of construction.

  4. Gasoline Vapor Recovery

    1979-01-01

    Gasoline is volatile and some of it evaporates during storage, giving off hydrocarbon vapor. Formerly, the vapor was vented into the atmosphere but anti-pollution regulations have precluded that practice in many localities, so oil companies and storage terminals are installing systems to recover hydrocarbon vapor. Recovery provides an energy conservation bonus in that most of the vapor can be reconverted to gasoline. Two such recovery systems are shown in the accompanying photographs (mid-photo at right and in the foreground below). They are actually two models of the same system, although.configured differently because they are customized to users' needs. They were developed and are being manufactured by Edwards Engineering Corporation, Pompton Plains, New Jersey. NASA technological information proved useful in development of the equipment.

  5. Efficacy of nanofibrous conduits in repair of long-segment sciatic nerve defects*

    Esmaeil Biazar; Saeed Heidari Keshel; Majid Pouya

    2013-01-01

    Our previous studies have histomorphological y confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit can be used to repair 30-mm-long sciatic nerve defects. However, the repair effects on rat behaviors remain poorly understood. In this study, we used nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous sciatic nerve to bridge 30-mm-long rat sciatic nerve gaps. Within 4 months after surgery, rat sciatic nerve functional re-covery was evaluated per month by behavioral analyses, including toe out angle, toe spread anal-ysis, walking track analysis, extensor postural thrust, swimming test, open-field analysis and noci-ceptive function. Results showed that rat sciatic nerve functional recovery was similar after nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous nerve grafting. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit is suitable in use for repair of long-segment sciatic nerve defects.

  6. Study on the air flow field of the drawing conduit in the spunbonding process

    Wu Li-Li

    2015-01-01

    Full Text Available The air flow field of the drawing conduit in the spunbonding process has a great effect on the polymer drawing, the filament diameter and orientation. A numerical simulation of the process is carried out, and the results are compared with the experimental data, showing good accuracy of the numerical prediction. This research lays an important foundation for the optimal design of the drawing conduit in the spunbonding process.

  7. The Himalayas: barrier and conduit for gene flow.

    Gayden, Tenzin; Perez, Annabel; Persad, Patrice J; Bukhari, Areej; Chennakrishnaiah, Shilpa; Simms, Tanya; Maloney, Trisha; Rodriguez, Kristina; Herrera, Rene J

    2013-06-01

    The Himalayan mountain range is strategically located at the crossroads of the major cultural centers in Asia, the Middle East and Europe. Although previous Y-chromosome studies indicate that the Himalayas served as a natural barrier for gene flow from the south to the Tibetan plateau, this region is believed to have played an important role as a corridor for human migrations between East and West Eurasia along the ancient Silk Road. To evaluate the effects of the Himalayan mountain range in shaping the maternal lineages of populations residing on either side of the cordillera, we analyzed mitochondrial DNA variation in 344 samples from three Nepalese collections (Newar, Kathmandu and Tamang) and a general population of Tibet. Our results revealed a predominantly East Asian-specific component in Tibet and Tamang, whereas Newar and Kathmandu are both characterized by a combination of East and South Central Asian lineages. Interestingly, Newar and Kathmandu harbor several deep-rooted Indian lineages, including M2, R5, and U2, whose coalescent times from this study (U2, >40 kya) and previous reports (M2 and R5, >50 kya) suggest that Nepal was inhabited during the initial peopling of South Central Asia. Comparisons with our previous Y-chromosome data indicate sex-biased migrations in Tamang and a founder effect and/or genetic drift in Tamang and Newar. Altogether, our results confirm that while the Himalayas acted as a geographic barrier for human movement from the Indian subcontinent to the Tibetan highland, it also served as a conduit for gene flow between Central and East Asia.

  8. Polytetrafluoroethylene pulmonary valve conduit implantation for chronic pulmonary insufficiency.

    Quintessenza, James A

    2014-12-01

    Pulmonary valve replacement in patients with congenital cardiac disease is now being performed with more liberal indications in light of the data that chronic pulmonary insufficiency is not a benign lesion. The beneficial effects of valve replacement with low operative mortality and morbidity support this approach. Many options exist for a pulmonary valve prosthesis, which underscores the fact that there is no ideal valve available. Our efforts are focussed around a synthetic valve that avoids the bio-degeneration of a bio-prosthesis and avoids the need for life-long coumadin. We developed a bicuspid (bileaflet) polytetrafluoroethylene valve design, which has now gone through three major revisions in >200 patients over 14 years. We began the experience utilising a polytetrafluoroethylene hand-sewn bicuspid valve in the right ventricular outflow tract, initially using 0.6 mm and more recently 0.1 mm polytetrafluoroethylene. The 0.1 mm thickness material functions well as a leaflet, maintaining a relatively thin and flexible nature. It does not calcify or initiate thromboses at least for the first several years. We identified issues with dehiscence of the leaflet from the right ventricular outflow tract muscle, especially in the larger, potentially expansive right ventricular outflow tracts, and this prompted our latest design change to place the valve within a polytetrafluoroethylene tube. This current version of the polytetrafluoroethylene valve conduit has excellent short-to-intermediate-term function. Further follow-up is necessary to determine late durability and life-long valve-related procedural risk for our patients.

  9. Comparison of a karst groundwater model with and without discrete conduit flow

    Saller, Stephen P.; Ronayne, Michael J.; Long, Andrew J.

    2013-01-01

    Karst aquifers exhibit a dual flow system characterized by interacting conduit and matrix domains. This study evaluated the coupled continuum pipe-flow framework for modeling karst groundwater flow in the Madison aquifer of western South Dakota (USA). Coupled conduit and matrix flow was simulated within a regional finite-difference model over a 10-year transient period. An existing equivalent porous medium (EPM) model was modified to include major conduit networks whose locations were constrained by dye-tracing data and environmental tracer analysis. Model calibration data included measured hydraulic heads at observation wells and estimates of discharge at four karst springs. Relative to the EPM model, the match to observation well hydraulic heads was substantially improved with the addition of conduits. The inclusion of conduit flow allowed for a simpler hydraulic conductivity distribution in the matrix continuum. Two of the high-conductivity zones in the EPM model, which were required to indirectly simulate the effects of conduits, were eliminated from the new model. This work demonstrates the utility of the coupled continuum pipe-flow method and illustrates how karst aquifer model parameterization is dependent on the physical processes that are simulated.

  10. In vitro evaluation of carbon-nanotube-reinforced bioprintable vascular conduits

    Dolati, Farzaneh; Yu, Yin; Zhang, Yahui; De Jesus, Aribet M.; Sander, Edward A.; Ozbolat, Ibrahim T.

    2014-04-01

    Vascularization of thick engineered tissue and organ constructs like the heart, liver, pancreas or kidney remains a major challenge in tissue engineering. Vascularization is needed to supply oxygen and nutrients and remove waste in living tissues and organs through a network that should possess high perfusion ability and significant mechanical strength and elasticity. In this paper, we introduce a fabrication process to print vascular conduits directly, where conduits were reinforced with carbon nanotubes (CNTs) to enhance their mechanical properties and bioprintability. In vitro evaluation of printed conduits encapsulated in human coronary artery smooth muscle cells was performed to characterize the effects of CNT reinforcement on the mechanical, perfusion and biological performance of the conduits. Perfusion and permeability, cell viability, extracellular matrix formation and tissue histology were assessed and discussed, and it was concluded that CNT-reinforced vascular conduits provided a foundation for mechanically appealing constructs where CNTs could be replaced with natural protein nanofibers for further integration of these conduits in large-scale tissue fabrication.

  11. A biosynthetic nerve guide conduit based on silk/SWNT/fibronectin nanocomposite for peripheral nerve regeneration.

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Zaminy, Arash; Kokabi, Mehrdad; Soleimani, Masoud; Mirahmadi, Fereshteh; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2013-01-01

    As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.

  12. A biosynthetic nerve guide conduit based on silk/SWNT/fibronectin nanocomposite for peripheral nerve regeneration.

    Fatemeh Mottaghitalab

    Full Text Available As a contribution to the functionality of nerve guide conduits (NGCs in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.

  13. Poly(lactic-co-glycolic acid) conduit for repair of injured sciatic nerve A mechanical analysis*

    Tao Yu; Changfu Zhao; Peng Li; Guangyao Liu; Min Luo

    2013-01-01

    Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic nerve injury. This study col ected the sciatic nerve from the gluteus maximus muscle from fresh human cadaver, and established 10-mm-long sciatic nerve injury models by removing the ischium, fol owing which poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts were transplanted. Scanning electron microscopy revealed that the axon and myelin sheath were torn, and the vessels of basilar membrane were obstructed in the poly(lactic-co-glycolic acid) con-duit-repaired sciatic nerve fol owing tensile testing. There were no significant differences in tensile tests with autogenous nerve graft-repaired sciatic nerve. Fol owing poly(lactic-co-glycolic acid) conduit transplantation for sciatic nerve repair, tensile test results suggest that maximum tensile load, maximum stress, elastic limit load and elastic limit stress increased compared with autogen-ous nerve grafts, but elastic limit strain and maximum strain decreased. Moreover, the tendencies of stress-strain curves of sciatic nerves were similar after transplantation of poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts. Results showed that after transplantation in vitro for sciatic nerve injury, poly(lactic-co-glycolic acid) conduits exhibited good intensity, elasticity and plasticity, indicating that poly(lactic-co-glycolic acid) conduits are suitable for sciatic nerve injury repair.

  14. Characteristics and biocompatibility of a biodegradable genipin-cross-linked gelatin/β-tricalcium phosphate reinforced nerve guide conduit.

    Yang, Yi-Chin; Shen, Chiung-Chyi; Huang, Tsung-Bin; Chang, Shun-Hsung; Cheng, Hsu-Chen; Liu, Bai-Shuan

    2010-10-01

    To modulate the mechanical properties of nerve guide conduit for surgical manipulation, this study develops a biodegradable composite containing genipin cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles as a nerve guide material. The conduit was dark bluish and round with a rough and compact outer surface compared to the genipin cross-linked gelatin conduit (without β-tricalcium phosphate). Water uptake and swelling tests indicate that the conduit noticeably increases the stability in water, and the hydrated conduit does not collapse and stenose. The conduit has a sufficiently high level of mechanical properties to serve as a nerve guide. After subcutaneous implantation on the dorsal side of a rat, the degraded conduit only evokes a mild tissue response, and the formation of a very thin fibrous capsule surrounds the conduit. This paper assesses the effectiveness of the conduit as a guidance channel when we use it to repair a 10 mm gap in the rat's sciatic nerve. The experimental results show no gross inflammatory reactions of the peripheral nerve tissues at the implantation site in either group. In overall gross examination, the diameter of the intratubular and newly formed nerve fibers in the conduits exceeds that of the silicone tubes during the implantation period. The quantitative results indicate the superiority of the conduits over the silicone tubes. This study microscopically observes the nerve regeneration in the tissue section at the middle region of all implanted conduits. Therefore, the histomorphometric assessment demonstrates that the conduit could be a candidate for peripheral nerve repair.

  15. Vapor pressures and enthalpies of vaporization of azides

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  16. Polymeric Nerve Conduits with Contact Guidance Cues Used in Nerve Repair

    G DAI; X NIU; J YIN

    2016-01-01

    In the modern life, the nerve injury frequently happens due to mechanical, chemical or thermal accidents. In the trivial injuries, the peripheral nerves can regenerate on their own; however, in most of the cases the clinical treatments are required, where relatively large nerve injury gaps are formed. Currently, the nerve repair can be accomplished by direct suture when the injury gap is not too large;while the autologous nerve graft working as the gold standard of peripheral nerve injury treatment for nerve injuries with larger gaps. However, the direct suture is limited by heavy tension at the suture sites, and the autologous nerve graft also has the drawbacks of donor site morbidity and insufifcient donor tissue. Recently, artiifcial nerve conduits have been developed as an alternative for clinical nerve repair to overcome the limitations associated with the above treatments. In order to further improve the efifciency of nerve conduits, various guidance cues are incorporated, including physical cues, biochemical signals, as well as support cells. First, this paper reviewed the contact guidance cues applied in nerve conduits, such as lumen ifllers, multi-channels and micro-patterns on the inner surface. Then, the paper focused on the polymeric nerve conduits with micro inner grooves. The polymeric nerve conduits were fabricated using the phase inversion-based ifber spinning techniques. The smart spinneret with grooved die was designed in the spinning platform, while different spinning conditions, including flow rates, air-gap distances, and polymer concentrations, were adjusted to investigate the inlfuence of fabrication conditions on the geometry of nerve conduits. The inner groove size in the nerve conduits can be precisely controlled in our hollow ifber spinning process, which can work as the efifcient contact guidance cue for nerve regeneration.

  17. Evolution of karst conduit networks in transition from pressurised flow to free surface flow

    Perne, M.; Covington, M. D.; Gabrovšek, F.

    2014-06-01

    We present a novel modelling approach to study the evolution of conduit networks in soluble rocks. Unlike the models presented so far, the model allows a transition from pressurised (pipe) flow to a free surface (open channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolutional enlargement within each time step and steps through time until a stable flow pattern establishes. The flow in each time step is calculated by calling the EPA Storm Water Management Model (EPA SWMM), which efficiently solves the 1-D Saint Venant equations in a network of conduits. We present several cases with low dip and sub-vertical networks to demonstrate mechanisms of flow pathway selection. In low dip models the inputs were randomly distributed to several junctions. The evolution of pathways progresses upstream: initially pathways linking outlets to the closest inputs evolve fastest because the gradient along these pathways is largest. When a pathway efficiently drains the available recharge, the head drop along the pathway attracts flow from the neighbouring upstream junctions and new connecting pathways evolve. The mechanism progresses from the output boundary inwards until all inputs are connected to the stable flow system. In the pressurised phase, each junction is drained by at least one conduit, but only one conduit remains active in the vadose phase. The selection depends on the initial geometry of a junction, initial distribution of diameters, the evolution in a pressurised regime, and on the dip of the conduits, which plays an important role in vadose entrenchment. In high dip networks, the vadose zone propagates downwards and inwards from the rim of the massif. When a network with randomly distributed initial diameters is supplied with concentrated recharge from the adjacent area, the sink point regresses up upstream along junctions connected to the prominent pathways. Large conductive structures provide deep penetration of high

  18. Evolution of karst conduit networks in transition from pressurised flow to free surface flow

    M. Perne

    2014-06-01

    Full Text Available We present a novel modelling approach to study the evolution of conduit networks in soluble rocks. Unlike the models presented so far, the model allows a transition from pressurised (pipe flow to a free surface (open channel flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolutional enlargement within each time step and steps through time until a stable flow pattern establishes. The flow in each time step is calculated by calling the EPA Storm Water Management Model (EPA SWMM, which efficiently solves the 1-D Saint Venant equations in a network of conduits. We present several cases with low dip and sub-vertical networks to demonstrate mechanisms of flow pathway selection. In low dip models the inputs were randomly distributed to several junctions. The evolution of pathways progresses upstream: initially pathways linking outlets to the closest inputs evolve fastest because the gradient along these pathways is largest. When a pathway efficiently drains the available recharge, the head drop along the pathway attracts flow from the neighbouring upstream junctions and new connecting pathways evolve. The mechanism progresses from the output boundary inwards until all inputs are connected to the stable flow system. In the pressurised phase, each junction is drained by at least one conduit, but only one conduit remains active in the vadose phase. The selection depends on the initial geometry of a junction, initial distribution of diameters, the evolution in a pressurised regime, and on the dip of the conduits, which plays an important role in vadose entrenchment. In high dip networks, the vadose zone propagates downwards and inwards from the rim of the massif. When a network with randomly distributed initial diameters is supplied with concentrated recharge from the adjacent area, the sink point regresses up upstream along junctions connected to the prominent pathways. Large conductive structures provide deep

  19. A novel electrospun nerve conduit enhanced by carbon nanotubes for peripheral nerve regeneration

    Yu, Wenwen; Jiang, Xinquan; Cai, Ming; Zhao, Wen; Ye, Dongxia; Zhou, Yong; Zhu, Chao; Zhang, Xiuli; Lu, Xiaofeng; Zhang, Zhiyuan

    2014-04-01

    For artificial nerve conduits, great improvements have been achieved in mimicking the structures and components of autologous nerves. However, there are still some problems in conduit construction, especially in terms of mechanical properties, biomimetic surface tomography, electrical conductivity and sustained release of neurotrophic factors or cells. In this study, we designed and fabricated a novel electrospun nerve conduit enhanced by multi-walled carbon nanotubes (MWNTs) on the basis of a collagen/poly(ɛ-caprolactone) (collagen/PCL) fibrous scaffold. Our aim was to provide further knowledge about the mechanical effects and efficacy of MWNTs on nerve conduits as well as the biocompatibility and toxicology of MWNTs when applied in vivo. The results showed that as one component, carboxyl MWNTs could greatly alter the composite scaffold’s hydrophilicity, mechanical properties and degradability. The electrospun fibers enhanced by MWNTs could support Schwann cell adhesion and elongation as a substrate in vitro. In vivo animal studies demonstrated that the MWNT-enhanced collagen/PCL conduit could effectively promote nerve regeneration of sciatic nerve defect in rats and prevent muscle atrophy without invoking body rejection or serious chronic inflammation. All of these results showed that this MWNT-enhanced scaffold possesses good biocompatibility and MWNTs might be excellent candidates as engineered nanocarriers for further neurotrophic factor delivery research.

  20. Electrospun Polycaprolactone/Polylactic Acid Nanofibers as an Artificial Nerve Conduit

    Zeeshan Ali Khatri

    2014-07-01

    Full Text Available Development of conduits made of biodegradable nanofibers is gaining substantial interest due to their suitability for nerve regeneration. Among all polymeric nanofibers PCL (Poly ?-Caprolactone is distinctively found for mechanical stability and PLLA (Poly (L-Lactic Acid for relatively faster biodegradability. The aim of this study is to investigate blending compatibility between PCL and PLLA and the ability to fabricate nanofibers conduits via electro spinning. The PCL-PLLA nano-fiber tubular made from different blend ratios of PCL-PLLA were electro spun. The electro spun nanofibers were continuously deposited over high speed rotating mandrel to fabricate nanofibers conduit having inner diameter of 2mm and the wall thickness of 55-65µm. The diameters of nano-fibers were between 715-860nm. FTIR (Fourier Transform Infrared spectroscopy used to analyze chemical change in the blends of nerve conduits, which revealed that the PCL-PLLA blend nanofiber exhibit characteristic peaks of both PCL and PLLA and was composition dependent. The crystallinity of PCL-PLLA tubes were studied using WAXD (Wide Angle Xray Diffraction. The morphology of nanofibers were investigated under SEM (Scanning Electron Microscope. The mechanical properties of the conduits were also tested; the Young?s modulus obtained for small diameter was 10MPa, twice as high as larger diameter.

  1. The Use of Degradable Nerve Conduits for Human Nerve Repair: A Review of the Literature

    M. F. Meek

    2005-01-01

    Full Text Available The management of peripheral nerve injury continues to be a major clinical challenge. The most widely used technique for bridging defects in peripheral nerves is the use of autologous nerve grafts. This technique, however, has some disadvantages. Many alternative experimental techniques have thus been developed, such as degradable nerve conduits. Degradable nerve guides have been extensively studied in animal experimental studies. However, the repair of human nerves by degradable nerve conduits has been limited to only a few clinical studies. In this paper, an overview of the available international published literature on degradable nerve conduits for bridging human peripheral nerve defects is presented for literature available until 2004. Also, the philosophy on the use of nerve guides and nerve grafts is given.

  2. A 6-year experience with radial artery conduit for myocardial revascularization

    A Sadeghpour-Tabaee

    2007-07-01

    Full Text Available Background: Excellent long-term patencies of arterial grafts are considered, superior to those of vein grafts. In this study, we present our 6 years experience in using radial artery as a conduit for myocardial revascularization. The aim of the present study was to assess the safety and early and mid term results of using radial artery in coronary artery bypass graft. Methods: The radial artery used as a conduit in 308 cases was evaluated during past 6 years, and the results obtained were processed and analyzed. Results: The operative morbidity comprised re-operation for bleeding in 3.2%, MI in 5%, with paresthesis and stitch abscess of the hand in 10% in and 3.5% respectively. Hospital mortality included 2 patients, one case being directly due to complication of harvesting radial artery.Conclusion: The results of present study were satisfactory with acceptable morbidity and mortality and favored the application of this conduit to CABG patients.

  3. Magma fracture and hybrid earthquakes in the conduit of Augustine Volcano

    Buurman, Helena; West, Michael E.

    2013-12-01

    exploit subtle but systematic shifts in seismic waveforms to examine a 2 h cluster of repeating hybrid volcanic earthquakes preceding the first magmatic explosions at Augustine Volcano in January 2006. We extract differential P wave traveltimes of <0.01 s to determine that the source locations migrated downward by approximately 35 m. Waveform characteristics, GPS observations, and visual reports of lava effusion at the summit suggest that the earthquakes were sourced by fracturing magma in the upper conduit. As the lava cooled and degassed at the surface, the conditions in the upper conduit changed causing the zone in which magma fracture could occur to move downward through the magma column. These changes may also have been the first indicators that the conduit was becoming choked, causing a buildup in pressure that resulted in the large magmatic explosions that followed 36 h later.

  4. Modeling magma flow in volcanic conduit with non-equilibrium crystallization

    Yulia, Tsvetkova

    2010-05-01

    Modeling magma flow in volcanic conduit including with non -equilibrium crystallization There is a set of models of magma flow in volcanic conduits which predicts oscillations in magma discharge during extrusion of lava domes. These models neglect heating of surrounding rocks and use 1D approximation of the flow in the conduit. Here magma flow is investigated with an account of heat exchange between surrounding rocks and magma and different dependences viscosity on temperature and crystal concentration. Stick-slip conditions were applied at the wall. The flow is assumed to be quasi-static and quasi 1D. Only vertical component of velocity vector is present, thus, we do not consider horizontal momentum balance. At the top of the conduit the pressure is assumed to be fixed, chamber pressure changes according with magma influx and outflux. First set of simulation was made for the viscosity that depends on cross-section average crystal concentration and parabolic velocity profile. In earlier models that account for crystal growth kinetics the temperature was allowed to change only due to the release of latent heat of crystallization. Heat transfer leads to cooling of the outer parts of the conduit leading to high crystal contents and high magma viscosities. Changes in viscosity result in changes in discharge rate. For the non-isothermal case there is no motion during most part of the cycle and a portion of magma solidifies at the top of the conduit forming a plug. During repose period chamber pressure is growing due to influx of fresh magma, and magma discharge rate starts to increase. Influx of hot magma into the conduit leads to decrease in friction resulting in a jump in discharge rate that lead to depressurization of magma chamber. Discharge rate decreases and magma solidifies again. For isothermal model with the same parameters discharge rate monotonically tends to the value of Qin. Simulation reveal that crystal content changes significantly across the conduit

  5. Spatially resolved information on karst conduit flow from in-cave dye tracing

    Lauber, U.; Ufrecht, W.; Goldscheider, N.

    2014-02-01

    Artificial tracers are powerful tools for investigating karst systems. Tracers are commonly injected into sinking streams or dolines, while springs serve as monitoring sites. The obtained flow and transport parameters represent mixed information from the vadose, epiphreatic and phreatic zones (that is, the aquifer remains a black box). Accessible active caves constitute valuable but underexploited natural laboratories to gain detailed insights into the hydrologic functioning of the aquifer. Two multi-tracer tests in the catchment of a major karst spring (Blautopf, Germany) with injections and monitoring in two associated water caves aimed at obtaining spatially and temporally resolved information on groundwater flow in different compartments of the system. Two tracers were injected into the caves to characterize the hydraulic connections between them and with the spring. Two injections at the land surface, far from the spring, aimed at resolving the aquifer's internal drainage structure. Tracer breakthrough curves were monitored by field fluorimeters in caves and at the spring. Results demonstrate the dendritic drainage structure of the aquifer. It was possible to obtain relevant flow and transport parameters for different sections of this system. The highest mean flow velocities (275 m h-1) were observed in the near-spring epiphreatic section (open-channel flow), while velocities in the phreatic zone (pressurized flow) were one order of magnitude lower. Determined conduit water volumes confirm results of water balances and hydrograph analyses. In conclusion, experiments and monitoring in caves can deliver spatially resolved information on karst aquifer heterogeneity and dynamics that cannot be obtained by traditional investigative methods.

  6. Havery Mudd 2014-2015 Computer Science Conduit Clinic Final Report

    Aspesi, G [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bai, J [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Deese, R [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shin, L [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-12

    Conduit, a new open-source library developed at Lawrence Livermore National Laboratories, provides a C++ application programming interface (API) to describe and access scientific data. Conduit’s primary use is for inmemory data exchange in high performance computing (HPC) applications. Our team tested and improved Conduit to make it more appealing to potential adopters in the HPC community. We extended Conduit’s capabilities by prototyping four libraries: one for parallel communication using MPI, one for I/O functionality, one for aggregating performance data, and one for data visualization.

  7. Small scale high resolution LiDAR measurements of a subglacial conduit

    Mankoff, K. D.; Gulley, J.

    2012-04-01

    We present direct measurements of surface roughness in a sub-glacial conduit system underneath the Rieperbreen Glacier, Svalbard, Norway. Data was collected with a low-cost (129 USD) Microsoft Kinect video game device used as a LIDAR sensor. Surface roughness is a primary control on water flow in rivers, channels, and cave conduit systems and understanding the effects of surface roughness on water flow has been problematic due to lack of direct measurements of roughness in natural systems. We use the ice scallop dimensions to derive flow velocity and explore implications of the changing roughness parameters as the cave grows and shrinks.

  8. The grain-size distribution of pyroclasts: Primary fragmentation, conduit sorting or abrasion?

    Kueppers, U.; Schauroth, J.; Taddeucci, J.

    2013-12-01

    Explosive volcanic eruptions expel a mixture of pyroclasts and lithics. Pyroclasts, fragments of the juvenile magma, record the state of the magma at fragmentation in terms of porosity and crystallinity. The grain size distribution of pyroclasts is generally considered to be a direct consequence of the conditions at magma fragmentation that is mainly driven by gas overpressure in bubbles, high shear rates, contact with external water or a combination of these factors. Stress exerted by any of these processes will lead to brittle fragmentation by overcoming the magma's relaxation timescale. As a consequence, most pyroclasts exhibit angular shapes. Upon magma fragmentation, the gas pyroclast mixture is accelerated upwards and eventually ejected from the vent. The total grain size distribution deposited is a function of fragmentation conditions and transport related sorting. Porous pyroclasts are very susceptible to abrasion by particle-particle or particle-conduit wall interaction. Accordingly, pyroclastic fall deposits with angular clasts should proof a low particle abrasion upon contact to other surfaces. In an attempt to constrain the degree of particle interaction during conduit flow, monomodal batches of washed pyroclasts have been accelerated upwards by rapid decompression and subsequently investigated for their grain size distribution. In our set-up, we used a vertical cylindrical tube without surface roughness as conduit. We varied grain size (0.125-0.25; 0.5-1; 1-2 mm), porosity (0; 10; 30 %), gas-particle ratio (10 and 40%), conduit length (10 and 28 cm) and conduit diameter (2.5 and 6 cm). All ejected particles were collected after settling at the base of a 3.3 m high tank and sieved at one sieve size below starting size (half-Φ). Grain size reduction showed a positive correlation with starting grain size, porosity and overpressure at the vent. Although milling in a volcanic conduit may take place, porous pyroclasts are very likely to be a primary product

  9. Bricker's ileal conduit urinary diversion with a simple non-refluxing uretero ileal anastomosis

    Bernstein, I T; Bennicke, K; Rørdam, P;

    1991-01-01

    Fifty consecutive patients had ileal conduits constructed with a technically and quick simple antireflux ureteroileal anastomosis. Complications related to the ureteral implantation were studied retrospectively, and at follow-up (8 months-12 years later, median 3 years) conduit dysfunction...... anastomosis. which was treated successfully by two weeks drainage. Hydronephrosis deteriorated in 18 (26%) of the renal units, remained unchanged in 39 (57%) and improved in 11 (16%). Increases in plasma creatinine concentrations up to 200 mumol/l were found in eight patients, and in one patient it increased...

  10. Biological conduits combining bone marrow mesenchymal stem cells and extracellular matrix to treat long-segment sciatic nerve defects

    Yang Wang

    2015-01-01

    Full Text Available The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group, followed by the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve fibers, and a completely degraded and resorbed conduit, in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group. These results indicate that bridging 10-mm sciatic nerve defects with a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is beneficial for the regeneration and functional reconstruction of sciatic nerve. Better

  11. Magmatic Conduit Metallogenic System - A New Model for the Origin of Ore-deposits

    Su, S.; Tang, Z.; Wu, G.; Deng, J.; Xiao, Q.; Luo, Z.; Cui, Y.

    2013-12-01

    Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral

  12. Ecoulements intermittents de gaz et de liquide en conduite verticale Intermittent Gas and Liquid Flows in a Vertical Pipe.

    Line A.

    2006-11-01

    Full Text Available Le modèle présenté ici permet la pré-détermination du gradient de pression, du taux global de gaz, et de grandeurs caractéristiques de l'intermittence, dans un écoulement à poches et bouchons en conduite verticale. L'écriture des lois de conservation en moyenne phasique conditionnelle conduit à la définition d'une cellule moyenne équivalente. La fermeture du modèle est assurée par des lois de contrainte de cisaillement film-paroi, film-poche, bouchon-paroi, par une loi d'arrachage du gaz au culot de la poche, une loi de glissement du gaz dans les bouchons et par une loi de la vitesse moyenne de propagation des fronts de poches. Le calibrage et la qualification du modèle s'appuient sur deux banques de données, dont l'une a été obtenue avec des fluides pétroliers dans des conditions proches des situations industrielles (boucle diphasique de Boussens. The model described here can be used to predetermine the pressure gradient, the overall gas rate and the characteristic intermittence magnitudes in pocket and slug flow in a vertical pipe. The way governing equations in the conditional phase average are written defines an equivalent average cell. The model is closed by film/wall, film/pocket and slug/wall shear-stress laws, by a pulloff law for the gas at the bottom of the pocket, a slippage law for the gas in the slugs, and a mean propagation velocity law for the pocket fronts. The calibration and qualification of the model are based on two data banks, one of which contains data on petroleum fluids under conditions close to industrial situations (two-phase loop at Boussens.

  13. Nitric oxide permits hypoxia-induced lymphatic perfusion by controlling arterial-lymphatic conduits in zebrafish and glass catfish

    Dahl Ejby Jensen, Lasse; Cao, Renhai; Hedlund, Eva-Maria;

    2009-01-01

    and lymphatic perfusion. Here we show in the adult zebrafish and glass catfish (Kryptopterus bicirrhis) that blood-lymphatic conduits directly connect arterial vessels to the lymphatic system. Under hypoxic conditions, arterial-lymphatic conduits (ALCs) became highly dilated and linearized by NO...

  14. A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

    Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

    2014-08-01

    A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT.

  15. New mobile Raman lidar for measurement of tropospheric water vapor

    XIE Chenbo; ZHOU Jun; YUE Guming; QI Fudi; FAN Aiyuan

    2007-01-01

    The content of water vapor in atmosphere is very little and the ratio of volume of moisture to air is about 0.1%-3%,but water vapor is the most active molecule in atmosphere.There are many absorption bands in infrared(IR)wavelength for water vapor,and water vapor is also an important factor in cloud formation and precipitation,therefore it takes a significant position in the global radiation budget and climatic changes.Because of the advantages of the high resolution,wide range,and highly automatic operation,the Raman lidar has become a new-style and useful tool to measure water vapor.In this paper,first,the new mobile Raman lidar's structure and specifications were introduced.Second,the process method of lidar data was described.Finally,the practical and comparative experiments were made over Hefei City in China.The results of measurement show that this lidar has the ability to gain profiles of ratio of water vapor mixing ratio from surface to a height of about 8 km at night.Mean-while,the measurement of water vapor in daytime has been taken,and the profiles of water vapor mixing ratio at ground level have been detected.

  16. The Conduit and Whirlpooling: A New Theory of Knowledge Constitution and Dispersion

    Nzegwu, Azuka

    2010-01-01

    There is a new epistemological approach for exploring knowledge constitution and dispersal in a dynamic Web ecosystem. The approach has three pivots. The first presents virtual whirlpools as knowledge systems. The second introduces the creator of the system as the Conduit. The third formulates a theory of knowledge that involves the collective…

  17. Percutaneous transthoracic computed tomography-guided AICD insertion in a patient with extracardiac Fontan conduit.

    Murphy, Darra T

    2011-02-01

    Percutaneous pulmonary venous atrial puncture was performed under computed tomography guidance to successfully place an automated implantable cardiac defibrillator into a 26-year-old patient with extracardiac Fontan conduit who had presented with two out-of-hospital cardiac arrests. The procedure avoided the need for lead placement at thoracotomy.

  18. 76 FR 53678 - Calleguas Municipal Water District Notice of Surrender of Exemption (Conduit)

    2011-08-29

    ... Federal Energy Regulatory Commission Calleguas Municipal Water District Notice of Surrender of Exemption (Conduit) Pursuant to section 4.95(a) of the Commission's regulations,\\1\\ Calleguas Municipal Water... exemption for Project No. 11651 on June 7, 1999. Calleguas Municipal Water District, 87 FERC ] 62,256...

  19. 78 FR 69847 - North Side Canal Company; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    2013-11-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission North Side Canal Company; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and Motions To Intervene On November 5, 2013, North Side Canal Company, filed a notice...

  20. 78 FR 62351 - North Side Canal Company; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    2013-10-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission North Side Canal Company; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and Motions To Intervene On October 3, 2013, North Side Canal Company, filed a notice...

  1. Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects*

    Esmaeil Biazar; Saeed Heidari Keshel; Majid Pouya; Hadi Rad; Melody Omrani Nava; Mohammad Azarbakhsh; Shirin Hooshmand

    2013-01-01

    It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were macroscopi-cal y observed and histological y assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cel s and glial cel s in the regenerated nerves. Masson’s trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cel s on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects.

  2. A New Equation Solver for Modeling Turbulent Flow in Coupled Matrix-Conduit Flow Models.

    Hubinger, Bernhard; Birk, Steffen; Hergarten, Stefan

    2016-07-01

    Karst aquifers represent dual flow systems consisting of a highly conductive conduit system embedded in a less permeable rock matrix. Hybrid models iteratively coupling both flow systems generally consume much time, especially because of the nonlinearity of turbulent conduit flow. To reduce calculation times compared to those of existing approaches, a new iterative equation solver for the conduit system is developed based on an approximated Newton-Raphson expression and a Gauß-Seidel or successive over-relaxation scheme with a single iteration step at the innermost level. It is implemented and tested in the research code CAVE but should be easily adaptable to similar models such as the Conduit Flow Process for MODFLOW-2005. It substantially reduces the computational effort as demonstrated by steady-state benchmark scenarios as well as by transient karst genesis simulations. Water balance errors are found to be acceptable in most of the test cases. However, the performance and accuracy may deteriorate under unfavorable conditions such as sudden, strong changes of the flow field at some stages of the karst genesis simulations.

  3. 3D bioprinting of heterogeneous aortic valve conduits with alginate/gelatin hydrogels.

    Duan, Bin; Hockaday, Laura A; Kang, Kevin H; Butcher, Jonathan T

    2013-05-01

    Heart valve disease is a serious and growing public health problem for which prosthetic replacement is most commonly indicated. Current prosthetic devices are inadequate for younger adults and growing children. Tissue engineered living aortic valve conduits have potential for remodeling, regeneration, and growth, but fabricating natural anatomical complexity with cellular heterogeneity remain challenging. In the current study, we implement 3D bioprinting to fabricate living alginate/gelatin hydrogel valve conduits with anatomical architecture and direct incorporation of dual cell types in a regionally constrained manner. Encapsulated aortic root sinus smooth muscle cells (SMC) and aortic valve leaflet interstitial cells (VIC) were viable within alginate/gelatin hydrogel discs over 7 days in culture. Acellular 3D printed hydrogels exhibited reduced modulus, ultimate strength, and peak strain reducing slightly over 7-day culture, while the tensile biomechanics of cell-laden hydrogels were maintained. Aortic valve conduits were successfully bioprinted with direct encapsulation of SMC in the valve root and VIC in the leaflets. Both cell types were viable (81.4 ± 3.4% for SMC and 83.2 ± 4.0% for VIC) within 3D printed tissues. Encapsulated SMC expressed elevated alpha-smooth muscle actin, while VIC expressed elevated vimentin. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting.

  4. SUIVI DE LA MIGRATION D’AVALAISON DES ANGUILLES PAR UNE CONDUITE DE DEBIT RESERVE

    LEGAULT A.

    2003-07-01

    Full Text Available Le suivi de la migration catadrome de l’anguille par une conduite de débit réservé a été réalisé sur le barrage de la retenue de Bois Joli sur le Frémur (dénivelé : 13,7 m ; 3 millions de m3. Une partie des migrateurs utilise cette conduite, au début de la saison de dévalaison quand elle représente la seule voie de transit mais également plus tard, lorsque le barrage déverse et que s’ouvre ainsi une seconde voie de passage. En raison des faibles débits d’alimentation et de l’implantation de l’entrée de la conduite on peut supposer que les anguilles prospectent la retenue pour trouver une voie de transit. L’efficacité de l’équipement, qui s’établit à 12 % de la dévalaison totale, concourt donc pour une part non négligeable au transit des anguilles. La partition des débits entre les différentes voies de migration semblerait essentielle pour définir leur efficacité. Malgré l’aménagement de la conduite, on observe une mortalité de 11 % des anguilles qui l’empruntent. Elle semble essentiellement liée à l’abrasion contre les parois et le papillon de la vanne. Dans de nombreux cas, la mortalité lors du passage dans les conduites de débit réservé doit être très importante, voire totale en raison de leur configuration et de leur mode de gestion. Cette mortalité tend à réduire le nombre des géniteurs produit par le bassin versant. Les anguilles marquées qui ont franchi le barrage grâce à la conduite avant le pic de migration stoppent leur progression en aval. Elles la reprennent quelques semaines plus tard quand le barrage déverse ou l’année suivante. Ce second constat confirme les effets des retenues sur la vitesse de migration. L’utilisation des conduites de débit réservé par les anguilles d’avalaison devrait être prise en compte lors de leur conception et de leur gestion afin de réduire les risques de mortalité.

  5. Numerical investigation of temporal changes in volcanic deformation caused by a gas slug ascent in the conduit

    Kawaguchi, Ryohei; Nishimura, Takeshi

    2015-09-01

    Strombolian type eruptions are considered to be generated by a sudden release of a large gas slug that migrates upward in the conduit filled with a low viscous basaltic magma. We examine volcano deformations caused by such a gas slug to understand the Strombolian eruption mechanism from geodetic observation data. We model spatio-temporal pressure changes in the conduit by using a gas slug ascent model presented by James et al. (2008). As a gas slug ascends in the conduit, its volume expands because of depressurization. Hence, the magma head lifts up in the conduit and the upper part of the conduit wall is stressed. In the conduit, magma pressure increases with depth according to the bulk density of magma: the gas slug part with a low density is characterized by a small pressure gradient, while the other parts, consisting of melt, are characterized by a large pressure gradient. We numerically calculate volcano deformations caused by the spatio-temporal changes of magma pressure predicted from the basic equations representing gas slug locations in the conduit. Simulation results show that the radial and vertical displacements and tilt changes indicate volcano deformations that represent the inflation originating from the stress increase at the upper part of conduit. As the gas slug reaches the shallow part of conduit, the rate of inflation observed in the radial displacement decreases, the vertical displacement starts to move downward, and the tilt turns to show down toward the crater. These deflation signals are caused by a moving deflation source in the conduit that is formed beneath the gas slug. Since these predicted features are not observed in the tilt records associated with explosions at Stromboli volcano (Genco and Ripepe, 2010), it is necessary to modify the gas slug ascent model or to introduce other mechanisms to better understand the magma dynamics of Strombolian eruption.

  6. Modeling Solute Reactivity in a Phreatic Solution Conduit Penetrating a Karst Aquifer

    Field, M.

    2014-12-01

    A two-dimensional model for solute migration, transformation, and sorption in a phreatic solution conduit penetrating a karst aquifer is presented in which the solute is anthropogenic to the natural system. Transformation of a reacting solute in a solution conduit has generally been accepted as likely occurring but actual physical measurements and mathematical analyses of the suspected process are lacking, primarily because of the logistics of sample collection and the complexities associated with solute transport through solution conduits. The model demonstrates how a reacting solute might be converted to a product solute some of which then diffuses to the solution conduit wall where it may become adsorbed. Model effects vary for laminar flow and turbulent flow in the axial direction. Laminar and turbulent diffusion in the radial direction also exhibits marked differences. In addition to single reaction zones simulations considered multiple adjacent and nonadjacent reaction zones, both with varying reaction rates. Reaction zones were found to enhance subsequent reactions due to some overlap resulting from the hydrodynamic dispersion caused by the axial flow. The simulations showed that varying the reaction rate coefficient strongly affects solute reactions, but that varying deposition coefficients had only minimal impacts. Application of the model to a tracer test that used the tracer dye, Rhodamine WT which readily converts to deaminoalkylated Rhodamine WT after release, illustrates how the model may be used to suggest a possible cause for less than 100% tracer mass recovery. In terms of pollutants in a karst aquifer the model suggests a possible explanation for pollutant transformation in a solution conduit.

  7. Welding of pyroclastic conduit infill: A mechanism for cyclical explosive eruptions

    Kolzenburg, S.; Russell, J. K.

    2014-07-01

    Vulcanian-style eruptions are small- to moderate-sized, singular to cyclical events commonly having volcanic explosivity indices of 1-3. They produce pyroclastic flows, disperse tephra over considerable areas, and can occur as precursors to larger (e.g., Plinian) eruptions. The fallout deposits of the 2360 B.P. eruption of Mount Meager, BC, Canada, contain bread-crusted blocks of welded breccia as accessory lithics. They display a range of compaction/welding intensity and provide a remarkable opportunity to constrain the nature and timescales of mechanical processes operating within explosive volcanic conduits during repose periods between eruptive cycles. We address the deformation and porosity/permeability reduction within natural pyroclastic deposits infilling volcanic conduits. We measure the porosity, permeability, and ultrasonic wave velocities for a suite of samples and quantify the strain recorded by pumice clasts. We explore the correlations between the physical properties and deformation fabric. Based on these correlations, we reconstruct the deformation history within the conduit, model the permeability reduction timescales, and outline the implications for the repressurization of the volcanic conduit. Our results highlight a profound directionality in the measured physical properties of these samples related to the deformation-induced fabric. Gas permeability varies drastically with increasing strain and decreasing porosity along the compaction direction of the fabric but varies little along the elongation direction of the fabric. The deformation fabric records a combination of compaction within the conduit and postcompaction stretching associated with subsequent eruption. Model timescales of these processes are in good agreement with repose periods of cyclic vulcanian eruptions.

  8. Fabrication of Off-the-Shelf Multilumen Poly(Ethylene Glycol) Nerve Guidance Conduits Using Stereolithography.

    Arcaute, Karina; Mann, Brenda K; Wicker, Ryan B

    2011-01-01

    A manufacturing process for fabricating off-the-shelf multilumen poly(ethylene glycol) (PEG)-based nerve guidance conduits (NGCs) was developed that included the use of stereolithography (SL). A rapid fabrication strategy for complex 3D scaffolds incorporated postprocessing with lyophilization and sterilization to preserve the scaffold, creating an implantable product with improved suturability. SL is easily adaptable to changes in scaffold design, is compatible with various materials and cells, and can be expanded for mass manufacture. The fabricated conduits were characterized using optical and scanning electron microscopy, and measurements of swelling ratio, dimensional swelling factor, resistance to compression, and coefficient of friction were performed. Water absorption curves showed that the conduits after lyophilization and sterilization return easily and rapidly to a swollen state when placed in an aqueous solution, successfully maintaining their original overall structure as required for implantation. Postprocessed conduits at the swollen state were less slippery and therefore easier to handle than those without postprocessing. Suture pullout experiments showed that NGCs fabricated with a higher concentration of PEG were better able to resist suture pullout. NGCs having a multilumen design demonstrated a better resistance to compression than a single-lumen design with an equivalent surface area, as well as a greater force required to collapse the design. Conduits fabricated with a higher PEG concentration were shown to have compressive resistances comparable to those of commercially available NGCs. The use of SL with PEG and the manufacturing process developed here shows promise for improving the current state of the art in peripheral nerve repair strategies.

  9. Speleogenetic effects of interaction between deeply derived fracture-conduit flow and intrastratal matrix flow in hypogene karst settings

    Tymokhina Elizaveta

    2012-07-01

    Full Text Available In carbonate rocks, especially in those with high primary porosity such as most Cenozoic carbonates, the interaction between deeply derived rising flow through sub-vertical fracture-controlled conduits and intrastratal matrix flow of shallower systems can invoke mixing cor- rosion and result in prominent speleogenetic effects. This paper outlines a conceptual model of such interaction and provides instructive field examples of relevant morphological effects from two different regions within the Prichernomorsky (north Black Sea basin, where karst features are developed in lower Pliocene, Eocene and Paleocene limestones. In the Crimean fore-mountain region, extensive steep to ver- tical limestone scarps formed through recent exposure of hypogenic fracture-controlled conduits provide outstanding possibilities to directly examine details of the original karstic porosity. The morphological effects of the conduit/matrix interaction, documented in both caves and exposed scarps, include lateral widening of sub-vertical conduits within the interaction intervals (formation of lateral notches and niches and the development of side bedding-parallel conduits, pockets and vuggy-spongework zones. Natural convection circulation, invoked by interaction of the two flow systems, spreads the morphological effects throughout the conduit space above the interaction interval. Where the interaction of the two flow systems is particularly strongly localized, such as along junctions of two vertical fracture sets, the resultant morphological effect can take the form of isolated chambers. The variety of speleogenetic features developed through the conduit/matrix interaction, can be broadly grouped into two categories: 1 variously shaped swells of the major fracture conduit itself (morphological fea- tures of its walls – niches and pockets, and 2 features of the vuggy-spongework halo surrounding the conduit. This halo includes clustered and stratiform cavities, spongework

  10. Flow patterns and boundary conditions for inlet and outlet conduits of large pump system with low head

    徐磊; 陆伟刚; 陆林广; 董雷; 王兆飞

    2014-01-01

    The flow patterns in the inlet and outlet conduits have a decisive effect on the safe, stable, and highly efficient operation of the pump in a large pumping station with low head. The numerical simulation of three-dimensional (3D) turbulence flow in conduits is an important method to study the hydraulic performance and conduct an optimum hydraulic design for the conduits. With the analyses of the flow patterns in the inlet and outlet conduits, the boundary conditions of the numerical simulation for them can be determined. The main obtained conclusions are as follows: (i) Under normal operation conditions, there is essentially no pre-swirl flow at the impeller chamber inlet of an axial-flow pump system, based on which the boundary condition at the inlet conduit may be defined. (ii) The circulation at the guide vane outlet of an axial-flow pump system has a great effect on the hydraulic performance of the outlet conduit, and there is optimum circulation for the performance. Therefore, it is strongly suggested to design the guide vane according to the optimum circulation. (iii) The residual circulation at the guide vane outlet needs to be considered for the inlet boundary condition of the outlet conduit, and the value of the circulation may be measured in a specially designed test model.

  11. Default Meanings

    K. M. Jaszczolt

    2006-01-01

    In this paper I present some aspects of the controversy surrounding the semantics/pragmatics boundary and offer a possible solution in the form of Default Semantics. First, I present a brief introduction to Paul Grice's approach to meaning as intentional communication. Next, I address the problem of the unit of which truth conditions should be predicated, assuming after Grice that the most successful approach to meaning has to make use of truth conditions.Further, I extend the discussion to some aspects of neo-Gricean pragmatics, most notably the issue of pragmatic processing that contributes to the truth-conditional representation and the proposed shortcuts through this processing in the form of default meanings. In the main part, I present the theory of Default Semantics ( Jaszczolt 2005a) , assess some arguments in favour of such an interactive theory of meaning that combines information from various sources, and address the issue of compositionality of meaning so conceived. In the final part, I apply the theory of Default Semantics to expressions with future-time reference in English in order to demonstrate the advantages of a framework that combines various types of information about utterance meaning in one, merged semantic representation. The main advantage turns out to be, in this domain, the unified treatment of all expressions with future-time reference.

  12. Intonational meaning.

    Prieto, Pilar

    2015-01-01

    Traditionally, prosodic studies have focused on the study of intonational form and the study of intonational meaning has been relatively neglected. Similarly, the fields of semantics and pragmatics have paid little attention to the pragmatic uses of intonation. As a result, there is no firm agreement within the linguistic community on how to integrate the analysis of intonational meaning across languages into a unified prosodic, semantic, and pragmatic approach. This article provides an overview of the literature on intonational meaning, describing the recent advances made in the fields of prosody, semantics/pragmatics, and syntax. Several theoretical approaches to explaining the semantics and pragmatics of intonation are presented. A common feature to most frameworks is that intonation (1) should be regarded as an integral part of linguistic grammar; and (2) typically encodes meanings related to the modal aspect of propositions. However, features such as compositionality, duality of structure, and context-dependency are still hotly debated issues. These features will be discussed from different theoretical perspectives, and we will identify potential advances related to the full integration of intonational meaning into dynamic and multidimensional models of meaning.

  13. Shallow conduit processes during the 1158 AD explosive eruption of Hekla volcano, Iceland

    Janebo, Maria; Houghton, Bruce; Thordarson, Thor; Larsen, Gudrun

    2015-04-01

    Hekla is one of the most frequently active silicic volcanic systems in the world, with multiple pre-historic large Plinian eruptions and 18 historical subplinian-Plinian eruptions. The common view is that the Plinian phases of the largest Hekla eruptions are all relatively homogeneous in style. Of the historical eruptions, only two were silicic: a Plinian eruption in 1104 and a smaller, less well characterized, eruption in 1158. We examine the dynamics of the 1158 eruption in detail with focus on the modulating role of shallow conduit processes. Grain size analysis, componentry, and density were used to characterize gradual and abrupt changes during the course of the eruption and quantitative vesicularity analysis was used to constrain the influence of bubble nucleation and coalescence. The 1158 eruption was a relatively steady, dry eruption with a more powerful opening phase followed by a lower intensity, waning phase accompanied by destabilization and collapse of the conduit walls. The juvenile pyroclasts are comprised of three types of microvesicular ragged pumice: white, grey, and banded. The abundance of grey pumice decreases as the eruption reaches maximum intensity, and then increases again during the waning phase of the eruption. The white pumices are more vesicular than the grey pumice, and the banded pumices have vesicularities that span predictably the range of the two end-members. The macroscopic differences between the white and grey pumice are accompanied by differences on a microscopic scale, most notably in a decrease in vesicle number density (VND) and a broadening of the vesicle size distribution, as well as increased crystal content. VND values of 0.5 to 1 E+6 mm-3 are similar to those recorded for the more powerful and sustained Plinian phases of the Novarupta 1912 and Taupo 181 eruptions in our laboratory. The 1158 pumice clasts display complex textures with adjacent domains of contrasting texture, alluding to complex nucleation, growth and

  14. Sciatic nerve repair with tissue engineered nerve: Olfactory ensheathing cells seeded poly(lactic-co-glygolic acid conduit in an animal model

    C W Tan

    2013-01-01

    Full Text Available Background and Aim: Synthetic nerve conduits have been sought for repair of nerve defects as the autologous nerve grafts causes donor site morbidity and possess other drawbacks. Many strategies have been investigated to improve nerve regeneration through synthetic nerve guided conduits. Olfactory ensheathing cells (OECs that share both Schwann cell and astrocytic characteristics have been shown to promote axonal regeneration after transplantation. The present study was driven by the hypothesis that tissue-engineered poly(lactic-co-glycolic acid (PLGA seeded with OECs would improve peripheral nerve regeneration in a long sciatic nerve defect. Materials and Methods: Sciatic nerve gap of 15 mm was created in six adult female Sprague-Dawley rats and implanted with PLGA seeded with OECs. The nerve regeneration was assessed electrophysiologically at 2, 4 and 6 weeks following implantation. Histopathological examination, scanning electron microscopic (SEM examination and immunohistochemical analysis were performed at the end of the study. Results: Nerve conduction studies revealed a significant improvement of nerve conduction velocities whereby the mean nerve conduction velocity increases from 4.2 ΁ 0.4 m/s at week 2 to 27.3 ΁ 5.7 m/s at week 6 post-implantation ( P < 0.0001. Histological analysis revealed presence of spindle-shaped cells. Immunohistochemical analysis further demonstrated the expression of S100 protein in both cell nucleus and the cytoplasm in these cells, hence confirming their Schwann-cell-like property. Under SEM, these cells were found to be actively secreting extracellular matrix. Conclusion: Tissue-engineered PLGA conduit seeded with OECs provided a permissive environment to facilitate nerve regeneration in a small animal model.

  15. Challenges of using electrical resistivity method to locate karst conduits-A field case in the Inner Bluegrass Region, Kentucky

    Zhu, J.; Currens, J.C.; Dinger, J.S.

    2011-01-01

    Conduits serve as major pathways for groundwater flow in karst aquifers. Locating them from the surface, however, is one of the most challenging tasks in karst research. Geophysical methods are often deployed to help locate voids by mapping variations of physical properties of the subsurface. Conduits can cause significant contrasts of some physical properties that can be detected; other subsurface features such as water-bearing fractures often yield similar contrasts, which are difficult to distinguish from the effects of the conduits. This study used electrical resistivity method to search for an unmapped karst conduit that recharges Royal Spring in the Inner Bluegrass karst region, Kentucky, USA. Three types of resistivity techniques (surface 2D survey, quasi-3D survey, and time-lapse survey) were used to map and characterize resistivity anomalies. Some of the major anomalies were selected as drilling targets to verify the existence of the conduits. Drilling near an anomaly identified by an electrical resistivity profile resulted in successful penetration of a major water-filled conduit. The drilling results also suggest that, in this study area, low resistivity anomalies in general are associated with water-bearing features. However, differences in the anomaly signals between the water-filled conduit and other water-bearing features such as water-filled fracture zones were undistinguishable. The electrical resistivity method is useful in conduit detection by providing potential drilling targets. Knowledge of geology and hydrogeology about the site and professional judgment also played important roles in locating the major conduit. ?? 2011 Elsevier B.V.

  16. Water vapor retrieval from OMI visible spectra

    H. Wang

    2014-01-01

    optimization of retrieval windows and parameters. The Air Mass Factor (AMF is calculated using look-up tables of scattering weights and monthly mean water vapor profiles from the GEOS-5 assimilation products. We convert from SCD to Vertical Column Density (VCD using the AMF and generate associated retrieval averaging kernels and shape factors. Our standard water vapor product has a median SCD of ~ 1.3 × 1023 molecule cm−2 and a median relative uncertainty of ~ 11% in the tropics, about a factor of 2 better than that from a similar OMI algorithm but using narrower retrieval window. The corresponding median VCD is ~ 1.2 × 1023 molecule cm−2. We have also explored the sensitivities to various parameters and compared our results with those from the Moderate-resolution Imaging Spectroradiometer (MODIS and the Aerosol Robotic NETwork (AERONET.

  17. Contextual Meaning and Word Meaning

    Istvan Kecskes

    2006-01-01

    The paper has three goals: 1 ) Explain the role of context and word in meaning construction and comprehension. 2) Present a model that can explain meaning generated by both monolingual and multilingual meaning construction systems. 3) Discuss how the model can be applied to explain major issues in pragmatics.Pragmatics is understood here in a narrow sense as defined by Sperber & Noveck: "...pragmatics is the study of how linguistic properties and contextual factors interact in the interpretation of utterances" ( Sperber & Noveck 2004:1 ). It is argued that world knowledge is available to interlocutors in two forms: as encapsulated in lexical items based on prior encounters and experience (conventionalized cognitive context), and as provided by the actual situational context framed by the situation in which the interaction takes place. Meaning formally expressed in the linguistic interactional context is created on-the-spot, and is the result of the interaction of the two sides of world knowledge and the actual situational context.The paper makes three claims: First, supremacy of context is not unconditional in language processing. Second,salient meaning rather than literal meaning of lexical units plays a central role in comprehension. Third, intercultural communication differs from intracultural communication in the conceptual content of conventionalized cognitive contexts rather than in communicative means.

  18. Data in support of in vivo studies of silk based gold nano-composite conduits for functional peripheral nerve regeneration

    Suradip Das

    2015-09-01

    Full Text Available In the present data article we report the in vitro and in vivo biocompatibility of fabricated nerve conduits described in Das et al. [1]. Green synthesised gold nanoparticles (GNPs were evaluated for their cytotoxicity in rat Schwann cells (SCTM41. We also describe herein the adhesion and proliferation of Schwann cells over the nanofibrous scaffolds. Methods describing surgical implantation of conduits in a rat sciatic nerve injury model, confirming its accurate implantation as well as the porosity and swelling tendency of the nerve conduits are illustrated in the various figures and graphs.

  19. Robot-Assisted Laparoscopic Partial Colpectomy and Intracorporeal Ileal Conduit Urinary Diversion (Bricker for Cervical Adenocarcinoma Recurrence

    Jennifer Uzan

    2015-01-01

    Full Text Available Ileal conduit urinary diversion (Bricker is a standard surgical open procedure. The Da Vinci robot allowed precision for this surgical procedure, especially for intracorporeal suturing. Meanwhile, few reports of robot-assisted laparoscopic ileal conduit diversion (Bricker are described in the literature. We report the case of a 69-year-old patient with a vaginal recurrence of cervical adenocarcinoma associated with vesicovaginal fistula treated by robot-assisted laparoscopic partial colpectomy and ileal conduit urinary diversion (Bricker. The robot-assisted laparoscopic procedure followed all surgical steps of the open procedure. Postoperative period was free of complications.

  20. Iron bromide vapor laser

    Sukhanov, V. B.; Shiyanov, D. V.; Trigub, M. V.; Dimaki, V. A.; Evtushenko, G. S.

    2016-03-01

    We have studied the characteristics of a pulsed gas-discharge laser on iron bromide vapor generating radiation with a wavelength of 452.9 nm at a pulse repetition frequency (PRF) of 5-30 kHz. The maximum output power amounted to 10 mW at a PRF within 5-15 kHz for a voltage of 20-25 kV applied to electrodes of the discharge tube. Addition of HBr to the medium produced leveling of the radial profile of emission. Initial weak lasing at a wavelength of 868.9 nm was observed for the first time, which ceased with buildup of the main 452.9-nm line.

  1. Solvents and vapor intrusion pathways.

    Phillips, Scott D; Krieger, Gary R; Palmer, Robert B; Waksman, Javier C

    2004-08-01

    Vapor intrusion must be recognized appropriately as a separate pathway of contamination. Although many issues resemble those of other forms of contamination (particularly its entryway, which is similar to that of radon seepage), vapor intrusion stands apart as a unique risk requiring case-specific action. This article addresses these issues and the current understanding of the most appropriate and successful remedial actions.

  2. Extra-anatomic right ventricle to pulmonary artery conduit: the apical-aortic equivalent for complex right ventricular outflow tract reconstruction.

    Mori, Makoto; Siddharthan, Ragavan; Kogon, Brian

    2015-03-01

    We describe the case of a 22-year-old with tetralogy of Fallot, who underwent complete repair with ventricular septal defect closure and right ventricle to pulmonary artery conduit placement. She has undergone numerous subsequent conduit changes, each complicated by early stenosis and failure. Unfortunately, serial conduit changes can become increasingly challenging. While extra-anatomic conduits have been described for complex left ventricular outflow tract obstruction, they have not been described for right-sided obstruction. Herein, we present a patient who underwent successful placement of an extra-anatomic valved right ventricle to pulmonary artery conduit in the setting of complex right ventricular outflow tract obstruction.

  3. Inhibition of calpains fails to improve regeneration through a peripheral nerve conduit.

    Hausner, Thomas; Marvaldi, Letizia; Márton, Gábor; Pajer, Krisztián; Hopf, Rudolf; Schmidhammer, Robert; Hausott, Barbara; Redl, Heinz; Nógrádi, Antal; Klimaschewski, Lars

    2014-04-30

    Intramuscular injection of the calpain inhibitor leupeptin promotes peripheral nerve regeneration in primates (Badalamente et al., 1989 [13]), and direct positive effects of leupeptin on axon outgrowth were observed in vitro (Hausott et al., 2012 [12]). In this study, we applied leupeptin (2mg/ml) directly to collagen-filled nerve conduits in the rat sciatic nerve transection model. Analysis of myelinated axons and retrogradely labeled motoneurons as well as functional 'CatWalk' video analysis did not reveal significant differences between vehicle controls and leupeptin treated animals. Therefore, leupeptin does not improve nerve regeneration via protease inhibition in regrowing axons or in surrounding Schwann cells following a single application to a peripheral nerve conduit suggesting indirect effects on motor endplate integrity if applied systemically.

  4. Stability of cable-in-conduit, force-cooled conductors: elementary theory

    Dresner, L.

    1979-01-01

    The recovery of cable-in-conduit conductors cooled by supercritical helium has been studied. The initial perturbation is a sudden, uniform deposition of heat. The problem has been solved, and answers have been obtained in the form of simple closed formulas under the simplifying assumption of constant thermophysical properties. Stability-optimized conductors have been identified and simple formulas for their material composition are given. A rule of design of cable-in-conduit conductors based on the existence of stability-optimized conductors is suggested. Some ''zero-flow'' experiments of Miller et al. have been analyzed, and it has been determined that for these experiments the effective heat transfer coefficient during the period of recovery is approximately 1000 Wm/sup -2/K/sup -1/.

  5. Crab burrows as conduits for groundwater-surface water exchange in Bangladesh

    Stahl, Mason O.; Tarek, M. H.; Yeo, Darren C. J.; Badruzzaman, A. B. M.; Harvey, Charles F.

    2014-12-01

    Groundwater recharge affects water budgets and groundwater quality on the deltas and floodplains of South and Southeast Asia. Rain and flooding rivers recharge groundwater during the monsoon; irrigated rice fields and surface water bodies recharge aquifers during the dry season. Groundwater throughout the region is severely contaminated by arsenic, and recent research suggests that quantifying and characterizing recharge is important to understand whether recharge flushes or mobilizes arsenic from aquifers. At a field site in Bangladesh, we found that burrows of terrestrial crabs short-circuit low-permeability surface sediments, providing the primary conduit for recharge. We combine field observations along with a model that couples isotope and water balances to quantify the effect of crab burrows on aquifer recharge. Given the wide distribution of burrowing crabs and the surficial geology, we suggest that crab burrows provide widespread conduits for groundwater recharge.

  6. Vapor phase heat transport systems

    Hedstrom, J.C.; Neeper, D.A.

    1985-09-01

    This report describes progress in theoretical and experimental investigations of various forms of a vapor transport system for solar space heating, which could also be applied to service water heating. Refrigerant is evaporated in a solar collector, which may be located on the external wall or roof of a building. The vapor is condensed in a passively discharged thermal storage unit located within the building. The condensed liquid can be returned to the collector either by a motor-driven pump or by a completely passive self-pumping mechanism in which the vapor pressure lifts the liquid from the condenser to the collector. The theoretical investigation analyzes this self-pumping scheme. Experiments in solar test cells compare the operation of both passive and active forms of the vapor system with the operation of a passive water wall. The vapor system operates as expected, with potential advantages over other passive systems in design flexibility and energy yield.

  7. Dynamics of vapor emissions at wire explosion threshold.

    Belony, Paul A; Kim, Yong W

    2010-10-01

    X-pinch plasmas have been actively studied in the recent years. Numerical simulation of the ramp-up of metallic vapor emissions from wire specimens shows that under impulsive Ohmic heating the wire core invariably reaches a supercritical state before explosion. The heating rate depends sensitively on the local wire resistance, leading to highly variable vapor emission flux along the wire. To examine the vapor emission process, we have visualized nickel wire explosions by means of shock formation in air. In a single explosion as captured by shadowgraphy, there usually appear several shocks with spherical or cylindrical wave front originating from different parts of the wire. Growth of various shock fronts in time is well characterized by a power-law scaling in one form or another. Continuum emission spectra are obtained and calibrated to measure temperature near the explosion threshold. Shock front structures and vapor plume temperature are examined.

  8. 33 CFR 154.828 - Vapor recovery and vapor destruction units.

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor recovery and vapor... SECURITY (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.828 Vapor recovery and vapor destruction units. (a) The inlet to a vapor recovery unit...

  9. Shallow conduit processes during the ad 1158 explosive eruption of Hekla volcano, Iceland

    Janebo, Maria H.; Houghton, Bruce F.; Thordarson, Thorvaldur; Larsen, Gudrun

    2016-10-01

    Hekla is one of the most frequently active felsic volcanic systems in the world, with several known pre-historic large Plinian eruptions and 18 historical subplinian to small Plinian eruptions. A common view is that Plinian eruptions of Hekla are relatively short lived and purely explosive events. In detail, these events exhibit subtle differences in terms of deposit characteristics, reflecting significant differences in eruption behaviour. Of the 18 historical eruptions, two had bulk magma compositions with >66 wt% SiO2: a Plinian eruption in ad 1104 and a smaller, less well characterised, but atypical subplinian eruption in ad 1158. The ad 1158 eruption was a relatively sustained, dry (magmatic) eruption with a more powerful opening phase followed by a lower intensity, waning phase accompanied by minor destabilisation and collapse of the conduit walls. We examine here the dynamics of the ad 1158 eruption, focussing on the role of shallow conduit processes in modulating eruption dynamics. Vesicularity data constrain the relative influence of bubble nucleation, growth, and coalescence. The juvenile pyroclasts are composed of two types of microvesicular pumice (white and grey) with contrasting vesicle number density, vesicle-size distribution, and phenocryst and microlite contents. Textural analysis shows that these pumices reflect heterogeneity developed pre- to syn-eruptively in the conduit and that entrainment of longer resident magma by faster ascending magma permitted magma of contrasting maturity to be fragmented simultaneously. In this regard, the mixed melt of the ad 1158 eruption contrasts with the compositionally homogeneous melt phase of the more powerful ad 1104 Plinian event, which was typified by more uniform conduit and eruption dynamics accompanying higher average ascent rates.

  10. Analysis of Cable-in-Conduit Conductors' DC Performance in Light of Strand's Experimental Properties

    TAN Yunfei; WENG Peide; LIU Fang; LI Shaolei

    2007-01-01

    Conductor qualification will be carried out with four Cable-in-Conduit Conductor (CICC) samples made of superconducting strands. The direct current (DC) performance of these samples will be tested in the SULTAN facility. The critical current densities of the strands can be well simulated by empirical equations. In this paper, a model is illustrated to predict the DC behaviour of the cable in light of the single strand's experimental properties. The simulation results were compared with experimental results.

  11. Large bifid ureteric calculus in a patient with an ileal conduit

    2012-01-01

    Urinary diversion after extirpative surgery of the bladder is done by various methods. Conduit urinary diversion is the most commonly practiced method of urinary diversion. It is relatively easy to perform and has a lower complication rate than other forms of diversion, e.g., orthotopic neobladder and continent cutaneous urinary diversion. Urolithiasis is a known and common complication of urinary diversion. Upper tract calculi in these cases often manifest symptomatically as occurs in the ge...

  12. A Lithium Vapor Box similarity experiment employing water vapor

    Schwartz, Ja; Jagoe, C.; Goldston, Rj; Jaworski, Ma

    2016-10-01

    Handling high power loads and heat flux in the divertor is a major challenge for fusion power plants. A detached plasma will likely be required. However, hydrogenic and impurity puffing experiments show that detached operation leads easily to X-point MARFEs, impure plasmas, degradation in confinement, and lower helium pressure at the exhaust. The concept of the Lithium Vapor Box Divertor is to use local evaporation and strong differential pumping through condensation to localize the gas-phase material that absorbs the plasma heat flux, and so avoid those difficulties. In order to design such a box first the vapor without plasma must be simulated. The density of vapor required can be estimated using the SOL power, major radius, poloidal box length, and cooling energy per lithium atom. For an NSTX-U-sized machine, the Knudsen number Kn spans 0.01 to 1, the transitional flow regime. This regime cannot handled by fluid codes or collisionless Monte Carlo codes, but can be handled by Direct Simulation Monte Carlo (DSMC) codes. To validate a DSMC model, we plan to build a vapor box test stand employing more-convenient water vapor instead of lithium vapor as the working fluid. Transport of vapor between the chambers at -50C will be measured and compared to the model. This work supported by DOE Contract No. DE-AC02-09CH11466.

  13. Vapor pressure measured with inflatable plastic bag

    1965-01-01

    Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

  14. Conduit enlargement during the precursory Plinian eruption of Aira Caldera, Japan

    Geshi, Nobuo; Miyabuchi, Yasuo

    2016-09-01

    Increase in magma flux as the result of conduit enlargement is one of the key processes that triggered caldera collapse and eruption of the Ito ignimbrite from Aira Caldera at ~29 ka. We examine the total volume of the pumice fall deposit, vertical variations in grain size of pumice, and the lithic content in the Osumi pumice deposit to investigate the trigger for caldera collapse. Wider distribution of the later-stage unit and the upward coarsening of grain size throughout the Osumi pumice fall deposit indicate an increase in magma discharge toward the onset of collapse. The total volume of lithic fragments in the Osumi pumice fall deposit is estimated as ~1.6 km3, based on the lithic content in several representative outcrops and the total volume of the Osumi pumice fall deposit. The lithic fragments in the Osumi pumice fall deposit indicate intense mechanical erosion of the conduit during the Plinian eruption prior to caldera collapse. Caldera collapse requires decompression of the magma chamber by withdrawal of magma; effective enlargement of the conduit diameter during precursory eruptive phases is one of the important processes that subsequently allow the rapid discharge of a large volume of magma, which in turn facilitates decompression of the reservoir and induces caldera collapse.

  15. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Radtke, Christine

    2016-01-01

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa) or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration. PMID:27775616

  16. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Christine Radtke

    2016-10-01

    Full Text Available Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  17. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits.

    Radtke, Christine

    2016-10-20

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa) or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  18. Chitosan conduits combined with nerve growth factor microspheres repair facial nerve defects

    Huawei Liu; Weisheng Wen; Min Hu; Wenting Bi; Lijie Chen; Sanxia Liu; Peng Chen; Xinying Tan

    2013-01-01

    Microspheres containing nerve growth factor for sustained release were prepared by a compound method, and implanted into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. In addition, chitosan conduits combined with nerve growth factor or normal saline, as wel as autologous nerve, were used as controls. At 90 days post-surgery, the muscular atrophy on the right upper lip was more evident in the nerve growth factor and normal sa-line groups than in the nerve growth factor-microspheres and autologous nerve groups. Electro-physiological analysis revealed that the nerve conduction velocity and amplitude were significantly higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. Moreover, histological observation il ustrated that the di-ameter, number, alignment and myelin sheath thickness of myelinated nerves derived from rabbits were higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. These findings indicate that chitosan nerve conduits com-bined with microspheres for sustained release of nerve growth factor can significantly improve facial nerve defect repair in rabbits.

  19. Thermo-Hydraulic Characteristics of Anatase Titania Nanofluids Flowing Through a Circular Conduit.

    Kristiawan, Budi; Kamal, Samsul; Yanuar

    2016-06-01

    The thermo-hydraulic characteristics of anatase titanium dioxide dispersed into distilled water with particle concentration of 0.1, 0.3, and 0.5 vol.% were investigated experimentally in this work. The influence of rheological behavior on hydrodynamic and convective heat transfer characteristics was evaluated under both laminar and turbulent flow conditions in a plain conduit and with twisted tape insert for twist ratio of 7. The nanofluids exhibited a strong shear-thinning behavior at low shear rate particularly higher particle concentration. The non-Newtonian titania nanofluids have also demonstrated a drag reduction phenomena in turbulent flow. At equal Reynolds number, the values of performance evaluation criterion in a conduit inserted a twisted tape were lower than those of in a plain conduit. It implies the unfavourable energy budget for twisted tape insert. The convective heat transfer coefficient does not gradually enhance with an increase of particle concentration. The flow features due mainly to the rheology of colloidal dispersions might be a reason for this phenomenon.

  20. Laminin-modified and aligned PHBV/PEO nanofibrous nerve conduits promote peripheral nerve regeneration.

    Zhang, Xiao-Feng; Liu, Hai-Xia; Ortiz, Lazarus Santiago; Xiao, Zhong-Dang; Huang, Ning-Ping

    2016-11-12

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has received much attention for its biodegradability and biocompatibility, characteristics which are required in tissue engineering. In this study, polyethylene oxide (PEO)-incorporated PHBV nanofibers with random or aligned orientation were obtained by electrospinning. For further use in vivo, the nanofiber films were made into nerve conduits after treated with NH3 plasma, which could improve the hydrophilicity of inner surfaces of nerve conduits and then facilitate laminin adsorption via electrostatic interaction for promoting cell adhesion and proliferation. Morphology of the surfaces of modified PHBV/PEO nanofibrous scaffolds were examined by scanning electron microscopy. Schwann cell viability assay was conducted and the results confirmed that the functionalized nanofibers were favorable for cell growth. Morphology of Schwann cells cultured on scaffolds showed that aligned nanofibrous scaffolds provided topographical guidance for cell orientation and elongation. Furthermore, 3D PHBV/PEO nerve conduits made from aligned and random-oriented nanofibers were implanted into 12-mm transected sciatic nerve rat model and subsequent analysis were conducted at 1 and 2 months post-surgery. The above functionalized PHBV/PEO scaffolds provide a novel and promising platform for peripheral nerve regeneration.

  1. Continent catheterizable conduit for urinary diversion in children: Applicability and acceptability

    Shailesh Solanki

    2015-01-01

    Full Text Available Background: Continent catheterizable conduit (CCC has made clean intermittent catheterization (CIC painless and easy. It is applicable in diverse clinical conditions. Nonetheless, convincing the parents for the need of conduit procedure is still difficult. Materials and Methods: A prospective study, included children who underwent CCC procedure from March 2008 to February 2013. The data were assessed for; diagnosis, type of conduit, number of preoperative counselling sessions before acceptance, role of "self-help group" in decision making, parental concern and satisfaction for the procedure. Results: Twenty-nine patients (males; 24, females; 5 underwent CCC procedure for various clinical conditions. The multiple preoperative counselling sessions and creation of "self-help groups" were helped them for decision making. The main concerns among parents were: (1 Impact of procedure on future fertility and sexual life. (2 Patency of native urethral channel. (3 Permanent urinary stoma over the abdomen. Conclusion: CCC procedures are applicable to a wide array of clinical situations with a good outcome. The acceptability of the CCC procedure improves with preoperative counselling of parent/child, initiation of preoperative per urethral CIC and creation of self-help groups.

  2. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

  3. The formation and migration of sand ripples in closed conduits: experiments with turbulent water flows

    Florez, Jorge Eduar Cardona

    2016-01-01

    The transport of solid particles by a fluid flow is frequently found in nature and industry. Some examples are the transport of sand in rivers and hydrocarbon pipelines. When the shear stresses exerted by a fluid flow on a granular bed remain moderate, some grains are set in motion without fluidizing the bed; the moving grains form a layer, known as bed load, that moves while maintaining contact with the fixed part of the bed. Under bed load conditions, the granular bed may become unstable, generating ripples and dunes. Sand ripples are commonly observed in closed conduits and pipes such as in petroleum pipelines, sewer systems, and dredging lines. Although of importance for many scientific domains and industrial applications, the formation of ripples in closed conduits is not well understood, and the problem is still open. This paper presents an experimental study on the formation and migration of sand ripples under a turbulent closed-conduit flow and bed-load conditions. In our experiments, fully-developed ...

  4. Large bifid ureteric calculus in a patient with an ileal conduit.

    Rajaian, Shanmugasundaram; Kekre, Nitin S

    2012-09-01

    Urinary diversion after extirpative surgery of the bladder is done by various methods. Conduit urinary diversion is the most commonly practiced method of urinary diversion. It is relatively easy to perform and has a lower complication rate than other forms of diversion, e.g., orthotopic neobladder and continent cutaneous urinary diversion. Urolithiasis is a known and common complication of urinary diversion. Upper tract calculi in these cases often manifest symptomatically as occurs in the general population. Stones in the conduit can have a variable clinical presentation. Asymptomatic presentation is also noted in a few cases. We report a case of a large silent bifid ureteric calculus within an ileal conduit in a woman who had undergone urinary diversion 32 years earlier. Plain X-ray of the abdomen is the only investigation necessary to rule out urinary lithiasis in those who have had urinary diversion for a long time. This simple tool can diagnose the condition well in advance and aid in planning the management of this condition.

  5. Large bifid ureteric calculus in a patient with an ileal conduit

    Shanmugasundaram Rajaian

    2012-01-01

    Full Text Available Urinary diversion after extirpative surgery of the bladder is done by various methods. Conduit urinary diversion is the most commonly practiced method of urinary diversion. It is relatively easy to perform and has a lower complication rate than other forms of diversion, e.g., orthotopic neobladder and continent cutaneous urinary diversion. Urolithiasis is a known and common complication of urinary diversion. Upper tract calculi in these cases often manifest symptomatically as occurs in the general population. Stones in the conduit can have a variable clinical presentation. Asymptomatic presentation is also noted in a few cases. We report a case of a large silent bifid ureteric calculus within an ileal conduit in a woman who had undergone urinary diversion 32 years earlier. Plain X-ray of the abdomen is the only investigation necessary to rule out urinary lithiasis in those who have had urinary diversion for a long time. This simple tool can diagnose the condition well in advance and aid in planning the management of this condition.

  6. Transcatheter Pulmonary Valve Replacement for Right Ventricular Outflow Tract Conduit Dysfunction After the Ross Procedure

    Gillespie, Matthew J; McElhinney, Doff B; Kreutzer, Jacqueline

    2015-01-01

    BACKGROUND: Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. METHODS: Retrospective review of databa...... early outcomes and durable valve function in the majority of Ross patients. Recurrent RVOT obstruction associated with stent fracture was the main reason for reintervention. Coronary compression is not uncommon in Ross patients and should be assessed prior to TPVR....... of databases from 3 prospective Melody TPV (Medtronic Inc, Minneapolis, MN) trials. RESULTS: Among 358 patients who were catheterized with the intent to implant a Melody TPV for RVOT conduit stenosis or regurgitation (PR) as part of 3 prospective multicenter studies, 67 (19%) had a prior Ross procedure....... Of these, 56 (84%) received a Melody valve; in 5 of the 11 patients who did not, the implant was aborted due to concern for coronary artery compression, and 1 implanted patient required emergent surgery for left coronary compression. The RVOT gradient decreased from a median 38 mm Hg to 13.5 mm Hg (p

  7. Neural Stem Cell Affinity of Chitosan and Feasibility of Chitosan-Based Porous Conduits as Scaffolds for Nerve Tissue Engineering

    WANG Aijun; AO Qiang; HE Qing; GONG Xiaoming; GONG Kai; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2006-01-01

    Neural stem cells (NSCs) are currently considered as powerful candidate seeding cells for regeneration of both spinal cords and peripheral nerves. In this study, NSCs derived from fetal rat cortices were co-cultured with chitosan to evaluate the cell affinity of this material. The results showed that NSCs grew and proliferated well on chitosan films and most of them differentiated into neuron-like cells after 4 days of culture. Then, molded and braided chitosan conduits were fabricated and characterized for their cytotoxicity, swelling, and mechanical properties. Both types of conduits had no cytotoxic effects on fibroblasts (L929 cells) or neuroblastoma (Neuro-2a) cells. The molded conduits are much softer and more flexible while the braided conduits possess much better mechanical properties, which suggests different potential applications.

  8. Biological conduits combining bone marrow mesenchymal stem cells and extracellular matrix to treat long-segment sciatic nerve defects

    Yang Wang; Zheng-wei Li; Min Luo; Ya-jun Li; Ke-qiang Zhang

    2015-01-01

    The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some re-spects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit+bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit+bone marrow mesenchymal stem cells+extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit+bone marrow mesenchymal stem cells+extracellular matrix gel group, followed by the polylactic glycolic acid conduit+bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the poly-lactic glycolic acid conduit+bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve ifbers, and a completely degraded and resorbed conduit, in the polylac-tic glycolic acid conduit+bone marrow mesenchymal stem cells+extracellular matrix gel group. These results indicate that bridging 10-mm sciatic nerve defects with a polylactic glycolic acid conduit+bone marrow mesenchymal stem cells+extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is ben-eifcial for the regeneration and functional reconstruction of sciatic nerve. Better regeneration was found with the

  9. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

    2009-04-15

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  10. Enhanced noradrenergic axon regeneration into schwann cell-filled PVDF-TrFE conduits after complete spinal cord transection.

    Lee, Yee-Shuan; Wu, Siliang; Arinzeh, Treena Livingston; Bunge, Mary Bartlett

    2017-02-01

    Schwann cell (SC) transplantation has been utilized for spinal cord repair and demonstrated to be a promising therapeutic strategy. In this study, we investigated the feasibility of combining SC transplantation with novel conduits to bridge the completely transected adult rat spinal cord. This is the first and initial study to evaluate the potential of using a fibrous piezoelectric polyvinylidene fluoride trifluoroethylene (PVDF-TrFE) conduit with SCs for spinal cord repair. PVDF-TrFE has been shown to enhance neurite growth in vitro and peripheral nerve repair in vivo. In this study, SCs adhered and proliferated when seeded onto PVDF-TrFE scaffolds in vitro. SCs and PVDF-TrFE conduits, consisting of random or aligned fibrous inner walls, were transplanted into transected rat spinal cords for 3 weeks to examine early repair. Glial fibrillary acidic protein (GFAP)(+) astrocyte processes and GFP (green fluorescent protein)-SCs were interdigitated at both rostral and caudal spinal cord/SC transplant interfaces in both types of conduits, indicative of permissivity to axon growth. More noradrenergic/DβH(+) (dopamine-beta-hydroxylase) brainstem axons regenerated across the transplant when greater numbers of GFAP(+) astrocyte processes were present. Aligned conduits promoted extension of DβH(+) axons and GFAP(+) processes farther into the transplant than random conduits. Sensory CGRP(+) (calcitonin gene-related peptide) axons were present at the caudal interface. Blood vessels formed throughout the transplant in both conduits. This study demonstrates that PVDF-TrFE conduits harboring SCs are promising for spinal cord repair and deserve further investigation. Biotechnol. Bioeng. 2017;114: 444-456. © 2016 Wiley Periodicals, Inc.

  11. Conduit margin heating and deformation during the AD 1886 basaltic Plinian eruption at Tarawera volcano, New Zealand.

    Schauroth, Jenny; Wadsworth, Fabian B; Kennedy, Ben; von Aulock, Felix W; Lavallée, Yan; Damby, David E; Vasseur, Jérémie; Scheu, Bettina; Dingwell, Donald B

    During explosive eruptions, a suspension of gas and pyroclasts rises rapidly within a conduit. Here, we have analysed textures preserved in the walls of a pyroclastic feeder dyke of the AD 1886 Tarawera basaltic Plinian fissure eruption. The samples examined consist of basaltic ash and scoria plastered onto a conduit wall of a coherent rhyolite dome and a welded rhyolitic dome breccia. We examine the textural evidence for the response of the wall material, built of ∼75 vol.% glass and ∼25 vol.% crystals (pore-free equivalent), to mass movement in the adjacent conduit. In the rhyolitic wall material, we quantify the orientation and aspect ratio of biotite crystals as strain markers of simple shear deformation, and interpret juxtaposed regions of vesiculation and vesicle collapse as evidence of conduit wall heating. Systematic changes occur close to the margin: (1) porosity is highly variable, with areas locally vesiculated or densified, (2) biotite crystals are oriented with their long axis parallel to the margin, (3) the biotites have greater aspect ratios close to the margin and (4) the biotite crystals are fractured. We interpret the biotite phenocryst deformation to result from crystal fracture, rotation and cleavage-parallel bookcase translation. These textural observations are inferred to indicate mechanical coupling between the hot gas-ash jet and the conduit wall and reheating of wall rock rhyolite. We couple these observations with a simple 1D conductive heating model to show what minimum temperature the conduit wall needs to reach in order to achieve a temperature above the glass transition throughout the texturally-defined deformed zone. We propose that conduit wall heating and resulting deformation influences conduit margin outgassing and may enhance the intensity of such large basaltic eruptions.

  12. Sciatic nerve regeneration in rats by a promising electrospun collagen/poly(ε-caprolactone nerve conduit with tailored degradation rate

    Jiang Xinquan

    2011-07-01

    Full Text Available Abstract Background To cope with the limitations faced by autograft acquisitions particularly for multiple nerve injuries, artificial nerve conduit has been introduced by researchers as a substitute for autologous nerve graft for the easy specification and availability for mass production. In order to best mimic the structures and components of autologous nerve, great efforts have been made to improve the designation of nerve conduits either from materials or fabrication techniques. Electrospinning is an easy and versatile technique that has recently been used to fabricate fibrous tissue-engineered scaffolds which have great similarity to the extracellular matrix on fiber structure. Results In this study we fabricated a collagen/poly(ε-caprolactone (collagen/PCL fibrous scaffold by electrospinning and explored its application as nerve guide substrate or conduit in vitro and in vivo. Material characterizations showed this electrospun composite material which was made of submicron fibers possessed good hydrophilicity and flexibility. In vitro study indicated electrospun collagen/PCL fibrous meshes promoted Schwann cell adhesion, elongation and proliferation. In vivo test showed electrospun collagen/PCL porous nerve conduits successfully supported nerve regeneration through an 8 mm sciatic nerve gap in adult rats, achieving similar electrophysiological and muscle reinnervation results as autografts. Although regenerated nerve fibers were still in a pre-mature stage 4 months postoperatively, the implanted collagen/PCL nerve conduits facilitated more axons regenerating through the conduit lumen and gradually degraded which well matched the nerve regeneration rate. Conclusions All the results demonstrated this collagen/PCL nerve conduit with tailored degradation rate fabricated by electrospinning could be an efficient alternative to autograft for peripheral nerve regeneration research. Due to its advantage of high surface area for cell attachment, it

  13. A New Statistical Model for Eruption Forecasting at Open Conduit Volcanoes: an Application to Mt Etna and Kilauea Volcanoes

    Passarelli, Luigi; Sanso, Bruno; Laura, Sandri; Marzocchi, Warner

    2010-05-01

    One of the main goals in volcanology is to forecast volcanic eruptions. A trenchant forecast should be made before the onset of a volcanic eruption, using the data available at that time, with the aim of mitigating the volcanic risk associated to the volcanic event. In other words, models implemented with forecast purposes have to take into account the possibility to provide "forward" forecasts and should avoid the idea of a merely "retrospective" fitting of the data available. In this perspective, the main idea of the present model is to forecast the next volcanic eruption after the end of the last one, using only the data available at that time. We focus our attention on volcanoes with open conduit regime and high eruption frequency. We assume a generalization of the classical time predictable model to describe the eruptive behavior of open conduit volcanoes and we use a Bayesian hierarchical model to make probabilistic forecast. We apply the model to Kilauea volcano eruptive data and Mt. Etna volcano flank eruption data. The aims of this model are: 1) to test whether or not the Kilauea and Mt Etna volcanoes follow a time predictable behavior; 2) to discuss the volcanological implications of the time predictable model parameters inferred; 3) to compare the forecast capabilities of this model with other models present in literature. The results obtained using the MCMC sampling algorithm show that both volcanoes follow a time predictable behavior. The numerical values of the time predictable model parameters inferred suggest that the amount of the erupted volume could change the dynamics of the magma chamber refilling process during the repose period. The probability gain of this model compared with other models already present in literature is appreciably greater than zero. This means that our model performs better forecast than previous models and it could be used in a probabilistic volcanic hazard assessment scheme. In this perspective, the probability of

  14. Influence of anatomical dominance and hypertension on coronary conduit arterial and microcirculatory flow patterns: a multiscale modeling study.

    Mynard, Jonathan P; Smolich, Joseph J

    2016-07-01

    Coronary hemodynamics are known to be affected by intravascular and extravascular factors that vary regionally and transmurally between the perfusion territories of left and right coronary arteries. However, despite clinical evidence that left coronary arterial dominance portends greater cardiovascular risk, relatively little is known about the effects of left or right dominance on regional conduit arterial and microcirculatory blood flow patterns, particularly in the presence of systemic or pulmonary hypertension. We addressed this issue using a multiscale numerical model of the human coronary circulation situated in a closed-loop cardiovascular model. The coronary model represented left or right dominant anatomies and accounted for transmural and regional differences in vascular properties and extravascular compression. Regional coronary flow dynamics of the two anatomical variants were compared under normotensive conditions, raised systemic or pulmonary pressures with maintained flow demand, and after accounting for adaptations known to occur in acute and chronic hypertensive states. Key findings were that 1) right coronary arterial flow patterns were strongly influenced by dominance and systemic/pulmonary hypertension; 2) dominance had minor effects on left coronary arterial and all microvascular flow patterns (aside from mean circumflex flow); 3) although systemic hypertension favorably increased perfusion pressure, this benefit varied regionally and transmurally and was offset by increased left ventricular and septal flow demands; and 4) pulmonary hypertension had a substantial negative effect on right ventricular and septal flows, which was exacerbated by greater metabolic demands. These findings highlight the importance of interactions between coronary arterial dominance and hypertension in modulating coronary hemodynamics.

  15. Multiwavelength Strontium Vapor Lasers

    Soldatov, A. N.; Yudin, N. A.

    2016-08-01

    Based on an analysis of experimental and theoretical works, modern notion on conditions of forming of population density inversion on self-terminating IR transitions of alkali-earth metals is given. It is demonstrated that there is a significant difference in the inversion formation in lasers on self-terminating transitions in the visible and near-IR ranges and lasers on self-terminating transitions of alkali-earth metals lasing IR lines in the mid-IR range. It is shown that in the discharge circuit of lasers on self-terminating metal atom transitions (LSMT) there are processes strengthening the influence of the known mechanism limiting the frequency and energy characteristics (FEC) of radiation caused by the presence of prepulse electron concentration. The mechanism of influence of these processes on FEC of the LSMT and technical methods of their neutralization are considered. The possibility of obtaining average lasing power of ~200 W from one liter volume of the active medium of the strontium vapor laser is demonstrated under conditions of neutralization of these processes.

  16. Modeling vapor dominated geothermal reservoirs

    Marconcini, R.; McEdwards, D.; Neri, G.; Ruffilli, C.; Schroeder, R.; Weres, O.; Witherspoon, P.

    1977-09-12

    The unresolved questions with regard to vapor-dominated reservoir production and longevity are reviewed. The simulation of reservoir behavior and the LBL computer program are discussed. The geology of Serrazzano geothermal field and its reservoir simulation are described. (MHR)

  17. Vapor Intrusion Facilities - South Bay

    U.S. Environmental Protection Agency — POINT locations for the South Bay Vapor Instrusion Sites were derived from the NPL data for Region 9. One site, Philips Semiconductor, was extracted from the...

  18. Utilização de valvas homólogas e heterólogas em condutos extracardíacos The use of homograph and heterograph valves in extracardiac conduits

    Rui Siqueira de Almeida

    1988-08-01

    Full Text Available O conceito do uso de um conduto extracardíaco para estabelecer uma via de saída, conectando o ventrículo direito com o tronco pulmonar, ou seus ramos, foi desenvolvido na década de 60. Entre 1971 e 1986, 335 pacientes receberam, no The Hospital for Sick Children, de Londres, condutos extracardíacos para o lado direito do coração; 176 destes foram homoenxertos aórticos, preservados em solução antibióticonutriente; 140 heteroenxertos (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley e 19 tubos não valvulados. Estes condutos foram usados na correção de defeitos cardíacos complexos. A idade média foi de 6,34 anos e o peso médio, de 17,8 kg. O diâmetro interno dos condutos variou de 8 a 30 mm. A mortalidade hospitalar foi de 29,2% e o seguimento dos sobrevivente teve uma duração máxima de 14,3 anos, sendo que apenas 40% delas foram relacionadas ao conduto extracardíaco. A curva atuarial, livre de obstrução, dos condutos extracardíacos foi significativa, quando se analisaram os homoenxertos, face a cada grupo de heteroenxertos (p The concept of using extracardiac conduits, to establish an outflow tract between the right ventricle and the pulmonary artery was developed on the sixties. Between 1971 and 1986, 335 patients received extracardiac conduits for the right heart, at The Hospital for Sick Children, London; 176 were antibiotic preserved aortic homografts (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley and 19 non-valved tubes. These conduits were used for the repair of complex congenital heart defects. The mean age of these groups was 6.34 ± 4.6 years and the mean weight 17.8 ± 10.8 kg. The internal diameter of the conduits varied from 8 to 30 mm. The hospital mortality was 29.2% and long-term follow-up of the survivals had a maximum period of 14,39 years. Sixty patients (17.9% were submited to 60 reoperations, being only 40% conduit related. The actuarial survival cun/e of freedom from obstruction was significant

  19. Confort 15 model of conduit dynamics: applications to Pantelleria Green Tuff and Etna 122 BC eruptions

    Campagnola, S.; Romano, C.; Mastin, L. G.; Vona, A.

    2016-06-01

    Numerical simulations are useful tools to illustrate how flow parameters and physical processes may affect eruption dynamics of volcanoes. In this paper, we present an updated version of the Conflow model, an open-source numerical model for flow in eruptive conduits during steady-state pyroclastic eruptions (Mastin and Ghiorso in A numerical program for steady-state flow of magma-gas mixtures through vertical eruptive conduits. U.S. Geological Survey Open File Report 00-209, 2000). In the modified version, called Confort 15, the rheological constraints are improved, incorporating the most recent constitutive equations of both the liquid viscosity and crystal-bearing rheology. This allows all natural magma compositions, including the peralkaline melts excluded in the original version, to be investigated. The crystal-bearing rheology is improved by computing the effect of strain rate and crystal shape on the rheology of natural magmatic suspensions and expanding the crystal content range in which rheology can be modeled compared to the original version ( Conflow is applicable to magmatic mixtures with up to 30 vol% crystal content). Moreover, volcanological studies of the juvenile products (crystal and vesicle size distribution) of the investigated eruption are directly incorporated into the modeling procedure. Vesicle number densities derived from textural analyses are used to calculate, through Toramaru equations, maximum decompression rates experienced during ascent. Finally, both degassing under equilibrium and disequilibrium conditions are considered. This allows considerations on the effect of different fragmentation criteria on the conduit flow analyses, the maximum volume fraction criterion ("porosity criterion"), the brittle fragmentation criterion and the overpressure fragmentation criterion. Simulations of the pantelleritic and trachytic phases of the Green Tuff (Pantelleria) and of the Plinian Etna 122 BC eruptions are performed to test the upgrades in

  20. Impact of pacing modality and biventricular pacing on cardiac output and coronary conduit flow in the post-cardiotomy patient.

    Healy, David G

    2012-02-03

    We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing first time elective coronary artery bypass grafting who required pacing following surgery were recruited. Comparison of cardiac output and coronary conduit flow was performed between VVI and DDD pacing with a single right ventricular lead and biventricular pacing lead placement. Cardiac output was measured using arterial pulse waveform analysis while conduit flow was measured using ultrasonic transit time methodology. Cardiac output was greatest with DDD pacing using right ventricular lead placement only [DDD-univentricular 5.42 l (0.7), DDD-biventricular 5.33 l (0.8), VVI-univentricular 4.71 l (0.8), VVI-biventricular 4.68 l (0.6)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.023) and VVI-biventricular pacing (P=0.001) but there was no significant advantage to DDD-biventricular pacing (P=0.45). In relation to coronary conduit flow, DDD pacing again had the highest flow [DDD-univentricular 55 ml\\/min (24), DDD-biventricular 52 ml\\/min (25), VVI-univentricular 47 ml\\/min (23), VVI-biventricular 50 ml\\/min (26)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.006) pacing but not significantly different to VVI-biventricular pacing (P=0.109) or DDD-biventricular pacing (P=0.171). Pacing with a DDD modality offers the optimal coronary conduit flow by maximising cardiac output. Biventricular lead placement offered no significant benefit to coronary conduit flow or cardiac output.

  1. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane

    Peng, Shih-Wen; Li, Ching-Wen; Chiu, Ing-Ming; Wang, Gou-Jen

    2017-01-01

    Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid) (PLGA) bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is feasible for use in clinical applications. PMID:28138239

  2. A Linearized Model for Wave Propagation through Coupled Volcanic Conduit-crack Systems Filled with Multiphase Magma

    Liang, C.; Dunham, E. M.; OReilly, O. J.; Karlstrom, L.

    2015-12-01

    Both the oscillation of magma in volcanic conduits and resonance of fluid-filled cracks (dikes and sills) are appealing explanations for very long period signals recorded at many active volcanoes. While these processes have been studied in isolation, real volcanic systems involve interconnected networks of conduits and cracks. The overall objective of our work is to develop a model of wave propagation and ultimately eruptive fluid dynamics through this coupled system. Here, we present a linearized model for wave propagation through a conduit with multiple cracks branching off of it. The fluid is compressible and viscous, and is comprised of a mixture of liquid melt and gas bubbles. Nonequilibrium bubble growth and resorption (BGR) is quantified by introducing a time scale for mass exchange between phases, following the treatment in Karlstrom and Dunham (2015). We start by deriving the dispersion relation for crack waves travelling along the multiphase-magma-filled crack embedded in an elastic solid. Dissipation arises from magma viscosity, nonequilibrium BGR, and radiation of seismic waves into the solid. We next introduce coupling conditions between the conduit and crack, expressing conservation of mass and the balance of forces across the junction. Waves in the conduit, like those in the crack, are influenced by nonequilibrium BGR, but the deformability of the surrounding solid is far less important than for cracks. Solution of the coupled system of equations provides the evolution of pressure and fluid velocity within the conduit-crack system. The system has various resonant modes that are sensitive to fluid properties and to the geometry of the conduit and cracks. Numerical modeling of seismic waves in the solid allows us to generate synthetic seismograms.

  3. Long-term result of guided nerve regeneration with an inert microporous polytetrafluoroethylene conduit

    2003-01-01

    Objective: To evaluate the long-term outcome of Polytetrafluoroethylene (PTFE) conduit in nerve repair and to provide more evidence in view of its potential application to achieve a satisfactory functional recovery in clinical settings. Methods: Thirty-six Wistar rats had their right sciatic nerve transected and were repaired with either conventional microsuture technique (Control group, n=18) or a PTFE conduit with a gap of 5 mm left between the nerve stumps (PTFE group, n=18). At 6 and 9 months after the operation, electrophysiological assessment and measurement of gastrocnemius muscle weight were conducted and morphology of the regenerated nerves were studied with image analysis. Results: At 6 months postoperatively, the nerve conduction velocity recovered to 60.86% and 54.36% (P>0.05), and the gastrocnemius muscle weight recovered to 50.89% and 46.11% (P>0.05) in the Control group and the PTFE group respectively. At 9 months postoperatively, the recovery rate was 65.99% and 58.79% for NCV (P>0.05), and 52.56% and 47.89% for gastrocnemius muscle weight (P>0.05) in the Control group and the PTFE group respectively. Regenerated nerve fibers in the PTFE group had a regular round shape with no fragmentation, wrinkling or splitting of the myelin sheath. Image analysis revealed that the ratio of the myelin area to the total fiber area was larger at 9 months than at 6 months in both groups (P<0.01). Conclusions: Microporous PTFE conduit may be an alternative for nerve repair allowing of guided nerve regeneration and functional recovery with no obvious adverse effect at long-term.

  4. Flambage vertical des conduites en souillées Vertical Buckling of Buried Pipes

    Bournazel C.

    2006-11-01

    Full Text Available Si l'apparition d'un flambage vertical des conduites rigides enfouies dans une tranchée est un phénomène assez rare, il peut ne pas en être de même pour des conduites flexibles dont les propriétés mécaniques sont de nature différente. Une étude théorique et expérimentale, ayant pour but de proposer une méthode analytique de calcul de l'apparition du flambage et de son évolution sous l'effet de la pression interne, a été réalisée. II apparaît que les conduites flexibles actuelles sont très sensibles à ce phénomène et qu'il serait nécessaire, pour l'éliminer à coup sûr, de réexaminer la structure des flexibles ou d'imaginer des artifices dans la procédure d'ensouillage Whereas the appearance of vertical buckling in rigid pipes buried in a trench is a relatively rare phenomenon, the same cannot be said for flexible pipes which have mechanical properties of a different nature. A theoretical and experimental study has been made with the aim of proposing an analytical method for computing the appearance of buckling and its evolution under the effect of outside pressure. Current flexible pipes appear to be very sensitive to this phenomenon, and to be certain of eliminating it the structure of flexible pipes should be reexamined or stratagems in the burying procedure should be devised.

  5. The past, present, and future viscous heat dissipation available for Greenland subglacial conduit formation

    Mankoff, Kenneth D.; Tulaczyk, Slawek M.

    2017-01-01

    Basal hydrology of the Greenland Ice Sheet (GIS) influences its dynamics and mass balance through basal lubrication and ice-bed decoupling or efficient water removal and ice-bed coupling. Variations in subglacial water pressure through the seasonal evolution of the subglacial hydrological system help control ice velocity. Near the ice sheet margin, large basal conduits are melted by the viscous heat dissipation (VHD) from surface runoff routed to the bed. These conduits may lead to efficient drainage systems that lower subglacial water pressure, increase basal effective stress, and reduce ice velocity. In this study we quantify the energy available for VHD historically at present and under future climate scenarios. At present, 345 km3 of annual runoff delivers 66 GW to the base of the ice sheet per year. These values are already ˜ 50 % more than the historical 1960-1999 value of 46 GW. By 2100 under IPCC AR5 RCP8.5 (RCP4.5) scenarios, 1278 (524) km3 of runoff may deliver 310 (110) GW to the ice sheet base. Hence, the ice sheet may experience a 5-to-7-fold increase in VHD in the near future which will enhance opening of subglacial conduits near the margin and will warm basal ice in the interior. The other significant basal heat source is geothermal heat flux (GHF), which has an estimated value of 36 GW within the present-day VHD area. With increasing surface meltwater penetration to the bed the basal heat budget in the active basal hydrology zone of the GIS will be increasingly dominated by VHD and relatively less sensitive to GHF, which may result in spatial changes in the ice flow field and in its seasonal variability.

  6. A robotic approach to mapping post-eruptive volcanic fissure conduits

    Parcheta, Carolyn E.; Pavlov, Catherine A.; Wiltsie, Nicholas; Carpenter, Kalind C.; Nash, Jeremy; Parness, Aaron; Mitchell, Karl L.

    2016-06-01

    VolcanoBot was developed to map volcanic vents and their underlying conduit systems, which are rarely preserved and generally inaccessible to human exploration. It uses a PrimeSense Carmine 1.09 sensor for mapping and carries an IR temperature sensor, analog distance sensor, and an inertial measurement unit (IMU) inside a protective shell. The first field test succeeded in collecting valuable scientific data but revealed several needed improvements, including more rugged cable connections and mechanical couplers, increased ground clearance, and higher-torque motors for uphill mobility. The second field test significantly improved on all of these aspects but it traded electrical ruggedness for reduced data collection speed. Data collected by the VolcanoBots, while intermittent, yield the first insights into the cm-scale geometry of volcanic fissures at depths of up to 25 m. VolcanoBot was deployed at the 1969 Mauna Ulu fissure system on Kīlauea volcano in Hawai'i. It collected first-of-its-kind data from inside the fissure system. We hypothesized that 1) fissure sinuosity should decrease with depth, 2) irregularity should be persistent with depth, 3) any blockages in the conduit should occur at the narrowest points, and 4) the fissure should narrow with depth until it is too narrow for VolcanoBot to pass or is plugged with solidified lava. Our field campaigns did not span enough lateral or vertical area to test sinuosity. The preliminary data indicate that 1) there were many irregularities along fissures at depth, 2) blockages occurred, but not at obviously narrow locations, and 3) the conduit width remained a consistent 0.4-0.5 m for most of the upper 10 m that we analyzed.

  7. Sensitivity analysis on parameters and processes affecting vapor intrusion risk

    Picone, S.; Valstar, J.R.; Gaans, van P.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2012-01-01

    A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the v

  8. Enhancing Peripheral Nerve Regeneration with a Novel Drug-Delivering Nerve Conduit

    2015-10-01

    were assembled using PTFE tubes and nitrile rubber based o-rings. PTFE tubes of diameter 1 mm were used as inner conduits (Figure 6). A laser was... CO2 for 72 h. For each experimental condition including control, four DRGs of similar size were used and the experiments were repeated 3-4 times. In...specific form of the dose-response, such as a linear increase across the range of doses. Interaction terms were used to test if the effect of drug

  9. Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    Moore, Karen A.; Zatorski, Raymond A.

    2007-10-02

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  10. Phyto-vesicles:conduit between conventional and novel drug delivery system

    Nidhi Mishra; Narayan P Yadav; Jaya Gopal Meher; Priyam Sinha

    2012-01-01

    Objective: To discuss the preparation, characterization, targeting and formulation aspect of phospholipids based drug delivery system i.e. Phyto-vesicles. Methods: The methods of phyto-vesicles preparation on R & D scale and different analytical techniques to characterize them have been discussed. Result: Phyto-vesicles are the advanced form of herbal drug delivery systems as its structure includes water soluble head and two fat soluble tails which act as an effective emulsifier. Conclusion: It is concluded that phytovesicular delivery system has improved pharmacokinetic and pharmacodynamic parameter as compared to conventional system Therefore, phyto-vesicles are called as conduit between conventional and novel drug delivery system.

  11. Oxidation of shallow conduit magma: Insight from μ-XANES analysis on volcanic ash particle

    Miwa, T.; Ishibashi, H.; Iguchi, M.

    2014-12-01

    Redox state of magma is important to understand dynamics of volcanic eruptions because magma properties such as composition of degassed volatiles, stability field of minerals, and rheology of magma depend on redox state. To evaluate redox state of magma, Fe3+/ΣFe ratio [= Fe3+/( Fe3++ Fe2+)] of volcanic glass has been measured non-destructively by Fe-K edge μ-XANES (micro X-ray Absorption Near Edge Structure) spectroscopy (e.g., Cottrell and Kelly, 2011). We performed textural, compositional, and Fe-K edge μ-XANES analyses on volcanic ash to infer oxidation process of magma at shallow conduit during eruption at Bromo Volcano, Indonesia. The volcanic ash particles were collected in 24th March 2011 by real-time sampling from ongoing activity. The activity was characterized by strombolian eruption showing magma head ascended to near the ground surface. The ash sample contains two type of volcanic glasses named as Brown and Black glasses (BrG and BlG), based on their color. Textual analysis shows microlite crystallinities are same in the two type of glasses, ranging from 0 to 3 vol.%. EPMA analyses show that all of the glasses have almost identical andesitic composition with SiO2 = 60 wt.%. In contrast, Fe-K edge μ-XANES spectra with the analytical method by Ishibashi et al. (in prep) demonstrate that BrG (Fe3+/ΣFe = 0.20-0.26) is more oxidized than BlG (Fe3+/ΣFe = 0.32-0.60). From combination of the glass composition, the measured Fe3+/ΣFe ratio and 1060 degree C of temperature (Kress and Carmichael, 1991), the oxygen fugacities are estimated to be NNO and NNO+4 for BrG and BlG, respectively. The volcanic glasses preserve syn-eruptive physicochemical conditions by rapid quenching due to their small size ranging from 125 to 250 μm. Our results demonstrate that BrG and BlG magmas are textually and chemically identical but their redox conditions are different at the eruption. The oxidation of magma can be caused by following two processes; 1) diffusive transport

  12. A Review of Vapor Intrusion Models

    Yao, Yijun; Suuberg, Eric M.

    2013-01-01

    A complete vapor intrusion (VI) model, describing vapor entry of volatile organic chemicals (VOCs) into buildings located on contaminated sites, generally consists of two main parts-one describing vapor transport in the soil and the other its entry into the building. Modeling the soil vapor transport part involves either analytically or numerically solving the equations of vapor advection and diffusion in the subsurface. Contaminant biodegradation must often also be included in this simulatio...

  13. Recent advances in vapor intrusion site investigations.

    McHugh, Thomas; Loll, Per; Eklund, Bart

    2017-02-22

    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed.

  14. The Lithium Vapor Box Divertor

    Goldston, Robert; Hakim, Ammar; Hammett, Gregory; Jaworski, Michael; Myers, Rachel; Schwartz, Jacob

    2015-11-01

    Projections of scrape-off layer width to a demonstration power plant suggest an immense parallel heat flux, of order 12 GW/m2, which will necessitate nearly fully detached operation. Building on earlier work by Nagayama et al. and by Ono et al., we propose to use a series of differentially pumped boxes filled with lithium vapor to isolate the buffering vapor from the main plasma chamber, allowing stable detachment. This powerful differential pumping is only available for condensable vapors, not conventional gases. We demonstrate the properties of such a system through conservation laws for vapor mass and enthalpy, and then include plasma entrainment and ultimately an estimate of radiated power. We find that full detachment should be achievable with little leakage of lithium to the main plasma chamber. We also present progress towards solving the Navier-Stokes equation numerically for the chain of vapor boxes, including self-consistent wall boundary conditions and fully-developed shocks, as well as concepts for an initial experimental demonstration-of-concept. This work supported by DOE Contract No. DE-AC02-09CH11466.

  15. Human immunodeficiency virus type 1 endocytic trafficking through macrophage bridging conduits facilitates spread of infection.

    Kadiu, Irena; Gendelman, Howard E

    2011-12-01

    Bridging conduits (BC) sustain communication and homeostasis between distant tethered cells. These are also exploited commonly for direct cell-to-cell transfer of microbial agents. Conduits efficiently spread infection, effectively, at speeds faster than fluid phase exchange while shielding the microbe against otherwise effective humoral immunity. Our laboratory has sought to uncover the mechanism(s) for these events for human immunodeficiency virus type one (HIV-1) infection. Indeed, in our prior works HIV-1 Env and Gag antigen and fluorescent virus tracking were shown sequestered into endoplasmic reticulum-Golgi organelles but the outcomes for spreading viral infection remained poorly defined. Herein, we show that HIV-1 specifically traffics through endocytic compartments contained within BC and directing such macrophage-to-macrophage viral transfers. Following clathrin-dependent viral entry, HIV-1 constituents bypass degradation by differential sorting from early to Rab11(+) recycling endosomes and multivesicular bodies. Virus-containing endocytic viral cargoes propelled by myosin II through BC spread to neighboring uninfected cells. Disruption of endosomal motility with cytochalasin D, nocodasole and blebbistatin diminish intercellular viral spread. These data lead us to propose that HIV-1 hijacks macrophage endocytic and cytoskeletal machineries for high-speed cell-to-cell spread.

  16. Conduit degassing and thermal controls on eruption styles at Mount St. Helens

    Schneider, Andrew; Rempel, Alan W.; Cashman, Katharine V.

    2012-12-01

    The explosivity of silicic eruptions depends on the interplay between magma rheology, exsolution kinetics, and degassing. Magma degassing is governed by the competing effects of vertical transport within the conduit and the lateral flux of gas out of the conduit (Diller et al., 2006; Jaupart and Allegre, 1991). We combine a simplified treatment of these degassing processes with thermodynamic modeling to examine the conditions present at Mount St. Helens during the spine extruding eruption from 2004 to 2008. We find that two parameters are primarily responsible for controlling the eruptive style: the magma chamber temperature, and a dimensionless parameter that gauges the efficiency of lateral degassing. Together, these parameters determine whether and where magma can solidify at depth to form a dense solid plug that is gradually extruded as a volcanic spine. We show that the small (50 oC) decrease in magma chamber temperature between eruptive activity in the 1980s and that of 2004-2008, combined with a modest increase in degassing efficiency associated with lower volumetric flux, can explain the observed change in erupted material from viscous lava flows to solidified spines. More generally, we suggest that similar threshold behavior may explain observed abrupt transitions in effusive eruptive styles at other intermediate composition volcanoes. Finally, we extrapolate our results to suggest that the increase in degassing efficiency accompanying decreasing magma supply rates may have caused the transition from explosive to effusive activity in late 1980.

  17. Functional activity of the rectum: A conduit organ or a storage organ or both?

    Ahmed Shafik; Randa M Mostafa; Ismail Shafik; Olfat EI-Sibai; Ali A Shafik

    2006-01-01

    AIM: To investigate whether the degree of rectal distension could define the rectum functions as a conduit or reservoir.METHODS: Response of the rectal and anal pressure to 2 types of rectal balloon distension, rapid voluminous and slow gradual distention, was recorded in 21 healthy volunteers (12 men, 9 women, age 41.7 ± 10.6 years).The test was repeated with sphincteric squeeze on urgent sensation.RESULTS: Rapid voluminous rectal distension resulted in a significant rectal pressure increase (P<0.001), an anal pressure decline (P<0.05) and balloon expulsion.The subjects felt urgent sensation but did not feel the 1st rectal sensation. On urgent sensation, anal squeeze caused a significant rectal pressure decrease (P <0.001) and urgency disappearance. Slow incremental rectal filling drew a rectometrogram with a "tone" limb representing a gradual rectal pressure increase during rectal filling, and an "evacuation limb" representing a sharp pressure increase during balloon expulsion. The curve recorded both the 1st rectal sensation and the urgent sensation.CONCLUSION: The rectum has apparently two functions: transportation (conduit) and storage, both depending on the degree of rectal filling. If the fecal material received by the rectum is small, it is stored in the rectum until a big volume is reached that can affect a degree of rectal distension sufficient to initiate the defecation reflex. Large volume rectal distension evokes directly the rectoanal inhibitory reflex with a resulting defecation.

  18. A tool for computing time-dependent permeability reduction of fractured volcanic conduit margins.

    Farquharson, Jamie; Wadsworth, Fabian; Heap, Michael; Baud, Patrick

    2016-04-01

    Laterally-oriented fractures within volcanic conduit margins are thought to play an important role in tempering eruption explosivity by allowing magmatic volatiles to outgas. The permeability of a fractured conduit margin - the equivalent permeability - can be modelled as the sum of permeability contributions of the edifice host rock and the fracture(s) within it. We present here a flexible MATLAB® tool which computes the time-dependent equivalent permeability of a volcanic conduit margin containing ash-filled fractures. The tool is designed so that the end-user can define a wide range of input parameters to yield equivalent permeability estimates for their application. The time-dependence of the equivalent permeability is incorporated by considering permeability decrease as a function of porosity loss in the ash-filled fractures due to viscous sintering (after Russell and Quane, 2005), which is in turn dependent on the depth and temperature of each fracture and the crystal-content of the magma (all user-defined variables). The initial viscosity of the granular material filling the fracture is dependent on the water content (Hess and Dingwell, 1996), which is computed assuming equilibrium depth-dependent water content (Liu et al., 2005). Crystallinity is subsequently accounted for by employing the particle-suspension rheological model of Mueller et al. (2010). The user then defines the number of fractures, their widths, and their depths, and the lengthscale of interest (e.g. the length of the conduit). Using these data, the combined influence of transient fractures on the equivalent permeability of the conduit margin is then calculated by adapting a parallel-plate flow model (developed by Baud et al., 2012 for porous sandstones), for host rock permeabilities from 10-11 to 10-22 m2. The calculated values of porosity and equivalent permeability with time for each host rock permeability is then output in text and worksheet file formats. We introduce two dimensionless

  19. The earliest open conduit eruptive center of the Etnean region: evidence from aeromagnetic, geophysical, and geological data

    Nicolosi, Iacopo; D'Ajello Caracciolo, Francesca; Branca, Stefano; Ferlito, Carmelo; Chiappini, Massimo

    2016-07-01

    At Mount Etna, the present-day active volcano is an open conduit structure characterized by continuous eruptive activity. Such conditions have been thought unique in the evolution of the Etnean volcano as well as in the Mediterranean region. However, a review study of available geophysical data and models, combined with geological records, petrographic and geochemical considerations, has led us to consider that a large area of about 28 km2 located in Val Calanna, on the eastern side of Valle del Bove, can be interpreted as the site of an old open conduit volcano. A dyke swarm outcrops in the area, whose deep alteration and fumarolization can be attributed to the sustained passage of volcanic gases over long periods. Radiometric dating yields an age of about 129 ka. This finding sheds new light on the evolution of Mount Etna volcano, indicating that the tectonic conditions leading to an open conduit volcano must also have been active in the past.

  20. Radical cystectomy and pelvic lymphadenectomy with ileal conduit urinary diversion and abdominal wall reconstruction: an interesting case of multidisciplinary management

    Sofos SS

    2015-01-01

    Full Text Available Stratos S Sofos,1 Ciaran Walsh,2 Nigel J Parr,2 Kevin Hancock11Whiston Hospital, Prescot, 2Arrowe Park Hospital, Wirral, Merseyside, UKAbstract: The ileal conduit for urinary diversion after radical cystectomy is a well-described procedure. Furthermore, parastomal hernias, prolapse, stenosis, and retraction of the stoma have been reported as some of the more common complications of this procedure. The subsequent repair of parastomal hernias with a biological mesh and the potential of the conduit to “tunnel” through it has also been described. In this case report, we present a combined repair of a large incisional hernia with a cystectomy and a pelvic lymphadenectomy for invasive bladder cancer, with the use of a biological mesh for posterior component abdominal wall primary repair as well as for support to the ileal conduit used for urinary diversion.Keywords: incisional hernia, posterior component separation, biological mesh 

  1. Use of nerve conduits for peripheral nerve injury repair A Web of Science-based literature analysis

    Jinniang Nan; Xuguang Hu; Hongxiu Li; Xiaonong Zhang; Renjing Piao

    2012-01-01

    OBJECTIVE: To identify global research trends in the use of nerve conduits for peripheral nerve injury repair.SELECTION CRITERIA: Inclusion criteria: peer-reviewed published articles on nerve conduits for peripheral nerve injury repair, indexed in the Web of Science; original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. Exclusion criteria: articles requiring manual searching or telephone access; documents not published in the public domain; and several corrected papers.MAIN OUTCOME MEASURES: (a) Annual publication output; (b) publication type; (c) publication by research field; (d) publication by journal; (e) publication by funding agency; (f) publication by author; (g) publication by country and institution; (h) publications by institution in China; (i) most-cited papers.CONCLUSION: Nerve conduits have been studied extensively for peripheral nerve regeneration; however, many problems remain in this field, which are difficult for researchers to reach a consensus.

  2. An opacity-sampled treatment of water vapor

    Alexander, David R.; Augason, Gordon C.; Johnson, Hollis R.

    1989-01-01

    Although the bands of H2O are strong in the spectra of cool stars and calculations have repeatedly demonstrated their significance as opacity sources, only approximate opacities are currently available, due both to the difficulty of accounting for the millions of lines involved and to the inadequacy of laboratory and theoretical data. To overcome these obstacles, a new treatment is presented, based upon a statistical representation of the water vapor spectrum derived from available laboratory data. This statistical spectrum of water vapor employs an exponential distribution of line strengths and random positions of lines whose overall properties are forced to reproduce the mean opacities observed in the laboratory. The resultant data set is then treated by the opacity-sampling method exactly as are all other lines, both molecular and atomic. Significant differences are found between the results of this improved treatment and the results obtained with previous treatments of water-vapor opacity.

  3. Evaluation of biodegradable polymer conduits--poly(L-lactic acid)--for guiding sciatic nerve regeneration in mice.

    Goulart, Camila Oliveira; Lopes, Fátima Rosalina Pereira; Monte, Zulmira Oliveira; Dantas, Severino Valentim; Souto, Allana; Oliveira, Júlia Teixeira; Almeida, Fernanda Martins; Tonda-Turo, Chiara; Pereira, Cristina Cardoso; Borges, Cristiano Piacsek; Martinez, Ana Maria Blanco

    2016-04-15

    Polymeric biomaterials are often used for stimulating nerve regeneration. Among different conduits, poly(lactide acid) - PLA polymer is considered to be a good substrate due to its biocompatibility and resorbable characteristics. This polymer is an aliphatic polyester which has been mostly used in biomedical application. It is an organic compound with low allergenic potential, low toxicity, high biocompatibility and predictable kinetics of degradation. In this study we fabricated and evaluated a PLA microporous hollow fiber as a conduit for its ability to bridge a nerve gap in a mouse sciatic nerve injury model. The PLA conduit was prepared from a polymer solution, throughout extrusion technique. The left sciatic nerve of C57BL/6 mouse was transected and the nerve stumps were placed into a resorbable PLA (PLA group) or a PCL conduit (PCL group), n=5 each group. We have also used another group in which the nerves were repaired by autograft (autograft group, n=5). Motor function was analyzed according to sciatic functional index (SFI). After 56days, the regenerated nerves were processed for light and electron microscopy and morphometric analyses were performed. A quantitative analysis of regenerated nerves showed significant increase in the number of myelinated fibers and blood vessels in animals that received PLA conduit. The PLA group exhibited better overall tissue organization compared to other groups. Presenting well-organized bundles, many regenerating clusters composed of preserved nerve fibers surrounded by layers of compacted perineurium-like cells. Also the SFI revealed a significant improvement in functional recovery. This work suggests that PLA conduits are suitable substrate for cell survival and it provides an effective strategy to be used to support axonal growth becoming a potential alternative to autograft.

  4. Are endothelial cell bioeffects from acoustic droplet vaporization proximity dependent?

    Seda, Robinson; Li, David; Fowlkes, J. Brian; Bull, Joseph

    2013-11-01

    Acoustic droplet vaporization (ADV) produces gas microbubbles that provide a means of selective occlusion in gas embolotherapy. Vaporization and subsequent occlusion occur inside blood vessels supplying the targeted tissue, such as tumors. Theoretical and computational studies showed that ADV within a vessel can impart high fluid mechanical stresses on the vessel wall. Previous in vitro studies have demonstrated that vaporization at an endothelial layer may affect cell attachment and viability. The current study is aimed at investigating the role of vaporization distance away from the endothelial layer. HUVECs were cultured in OptiCell™ chambers until reaching confluence. Dodecafluoropentane microdroplets were added, attaining a 10:1 droplet to cell ratio. A single ultrasound pulse (7.5 MHz) consisting of 16 cycles (~ 2 μs) and a 5 MPa peak rarefactional pressure was used to produce ADV while varying the vaporization distance from the endothelial layer (0 μm, 500 μm, 1000 μm). Results indicated that cell attachment and viability was significantly different if the distance was 0 μm (at the endothelial layer). Other distances were not significantly different from the control. ADV will significantly affect the endothelium if droplets are in direct contact with the cells. Droplet concentration and flow conditions inside blood vessels may play an important role. This work was supported by NIH grant R01EB006476.

  5. Nerve guidance conduit with a hybrid structure of a PLGA microfibrous bundle wrapped in a micro/nanostructured membrane

    Peng SW

    2017-01-01

    Full Text Available Shih-Wen Peng,1 Ching-Wen Li,2 Ing-Ming Chiu,3,4 Gou-Jen Wang1–3 1Graduate Institute of Biomedical Engineering, 2Department of Mechanical Engineering, 3PhD Program in Tissue Engineering and Regenerative Medicine, National Chung-Hsing University, Taichung, 4Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli, Taiwan Abstract: Nerve repair in tissue engineering involves the precise construction of a scaffold to guide nerve cell regeneration in the desired direction. However, improvements are needed to facilitate the cell migration/growth rate of nerves in the center of a nerve conduit. In this paper, we propose a nerve guidance conduit with a hybrid structure comprising a microfibrous poly(lactic-co-glycolic acid (PLGA bundle wrapped in a micro/nanostructured PLGA membrane. We applied sequential fabrication processes, including photolithography, nano-electroforming, and polydimethylsiloxane casting to manufacture master molds for the repeated production of the PLGA subelements. After demolding it from the master molds, we rolled the microfibrous membrane into a bundle and then wrapped it in the micro/nanostructured membrane to form a nerve-guiding conduit. We used KT98/F1B-GFP cells to estimate the migration rate and guidance ability of the fabricated nerve conduit and found that both elements increased the migration rate 1.6-fold compared with a flat PLGA membrane. We also found that 90% of the cells in the hybrid nano/microstructured membrane grew in the direction of the designed patterns. After 3 days of culturing, the interior of the nerve conduit was filled with cells, and the microfiber bundle was also surrounded by cells. Our conduit cell culture results also demonstrate that the proposed micro/nanohybrid and microfibrous structures can retain their shapes. The proposed hybrid-structured conduit demonstrates a high capability for guiding nerve cells and promoting cell migration, and, as such, is

  6. Estimated vapor pressure for WTP process streams

    Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-01-01

    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

  7. Families of similar events and modes of oscillation of the conduit at Yasur volcano (Vanuatu)

    Battaglia, Jean; Métaxian, Jean-Philippe; Garaebiti, Esline

    2016-08-01

    , sudden or progressive. These can be interpreted as representative of changes in the eruptive dynamics. The presence of similar EQs, especially for impulsive explosions, indicates that the source mechanism is reproducible and has a stable location for some periods. This favors a source process based on the oscillation of the conduit or oscillation of the edifice in response to the explosive decompression of gas slugs at the free surface of the conduit. Our results suggest that the seismic activity of Yasur is characterized by the presence of dominant modes of resonance of the conduit which may be influenced both by external and internal factors.

  8. Comment faire parler les images aux rayons X du conduit vocal

    Laprie Yves

    2014-07-01

    Full Text Available Cet article présente la méthodologie de construction, de dépouillement et d’exploitation d’une base de données cinéradiographiques. L’élaboration du contenu du corpus est un aspect essentiel puisqu’il doit prendre en compte les contraintes inhérentes à la technologie d’acquisition et l’objectif phonétique. Dans le cas de la cinéradiographie on privilégie des phrases courtes formées de mots et non de logatomes. Une base de données cinéradiographique est formée d’un très grand nombre d’images. Le dépouillement consiste à tracer le contour des articulateurs de la parole et ce travail doit être automatisé afin de pouvoir traiter un volume de données suffisant pour assurer une exploitation ultérieure pertinente. Des algorithmes de suivi semi-automatique ou automatique, ainsi qu’une interface très conviviale ont donc été développés pour atteindre cet objectif. Dans ce travail l’exploitation des corpus a consisté à développer et valider des modèles articulatoires en étudiant deux aspects : (1 l’utilisation d’un modèle construit sur un locuteur pour approcher la forme du conduit vocal d’un autre locuteur, (2 l’approximation précise du conduit vocal au voisinage de la constriction parce qu’elle a un impact important sur l’acoustique de la parole. Ces modèles, et plus généralement une représentation géométrique du conduit vocal, peuvent être utilisés en synthèse articulatoire afin d’étudier le lien entre les domaines articulatoire et acoustique. Nous montrons en particulier qu’il est possible de resynthétiser de la parole de bonne qualité à partir des contours extraits des films.

  9. Final OSWER Vapor Intrusion Guidance

    EPA is preparing to finalize its guidance on assessing and addressing vapor intrusion, which is defined as migration of volatile constituents from contaminated media in the subsurface (soil or groundwater) into the indoor environment. In November 2002, EPA issued draft guidance o...

  10. Simple Chemical Vapor Deposition Experiment

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  11. Hydrazine vapor inactivates Bacillus spores

    Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

    2016-05-01

    NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

  12. The sensitivity of conduit flow models to basic input parameters: there is no need for magma trolls!

    Thomas, M. E.; Neuberg, J. W.

    2012-04-01

    Many conduit flow models now exist and some of these models are becoming extremely complicated, conducted in three dimensions and incorporating the physics of compressible three phase fluids (magmas), intricate conduit geometries and fragmentation processes, to name but a few examples. These highly specialised models are being used to explain observations of the natural system, and there is a danger that possible explanations may be getting needlessly complex. It is coherent, for instance, to propose the involvement of sub-surface dwelling magma trolls as an explanation for the change in a volcanoes eruptive style, but assuming the simplest explanation would prevent such additions, unless they were absolutely necessary. While the understanding of individual, often small scale conduit processes is increasing rapidly, is this level of detail necessary? How sensitive are these models to small changes in the most basic of governing parameters? Can these changes be used to explain observed behaviour? Here we will examine the sensitivity of conduit flow models to changes in the melt viscosity, one of the fundamental inputs to any such model. However, even addressing this elementary issue is not straight forward. There are several viscosity models in existence, how do they differ? Can models that use different viscosity models be realistically compared? Each of these viscosity models is also heavily dependent on the magma composition and/or temperature, and how well are these variables constrained? Magma temperatures and water contents are often assumed as "ball-park" figures, and are very rarely exactly known for the periods of observation the models are attempting to explain, yet they exhibit a strong controlling factor on the melt viscosity. The role of both these variables will be discussed. For example, using one of the available viscosity models a 20 K decrease in temperature of the melt results in a greater than 100% increase in the melt viscosity. With changes of

  13. Boiler for generating high quality vapor

    Gray, V. H.; Marto, P. J.; Joslyn, A. W.

    1972-01-01

    Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets.

  14. Open system degassing, bubble rise and flow dynamics within volcanic conduits- an experimental approach

    Pioli, L.; Azzopardi, B. J.; Bonadonna, C.; Marchetti, E.; Ripepe, M.

    2009-12-01

    Open conduit basaltic volcanoes are characterized by frequent eruptions, usually consisting in mild Strombolian and Hawaiian explosions, alternating years to months of quiescence periods, with degassing activity from the central conduit. Recent improvements of thermal, video, radar and acoustic monitoring techniques have provided new powerful tools for the study of degassing processes and made available geophysical and geochemical datasets for many central volcanoes, such as Stromboli, Etna (Italy), Kilauea (Hawaii), Villarrica (Chile). These studies revealed that degassing is an unsteady, often pulsatory process, characterized by fluctuations in both intensity and composition of the emitted gases. Unambiguous interpretation of monitoring data of surface activity in terms of conduit dynamics and flow processes is, however, not possible, due to partial knowledge of the physical processes controlling the dynamics of two-phase flows in magmas. We performed a series of experiments to gain further insights on the dynamics of the gas-bubble rise in magmas within a cylindrical conduit, their ability to segregate and coalesce and the effect of these processes on the degassing dynamics. The experiments consisted in generating fluxes at variable intensities of air through stagnant water or glucose syrup in a bubble column apparatus 6.5 m high and with a diameter of 24 cm diameter. Glucose syrup and water are Newtonian liquids with viscosity ranging from 2.4 to 204.0 Pa*s and from 1.7 to 0.2 10 -3 Pa*s respectively, depending on temperature. Air was inserted at the base of the column through a variable number (1 to 25) of 5mm-diameter nozzles reaching surficial gas velocities of up to 0.5 m/s. The activity of the bubble column was monitored through temperature, pressure, void fraction and acoustic measurements and filmed by a high-speed camera with maximum resolution of 800x600 pixels. Pressure fluctuations, vesicularity and acoustic signal were then analyzed and correlated

  15. A novel approach to estimate the eruptive potential and probability in open conduit volcanoes.

    De Gregorio, Sofia; Camarda, Marco

    2016-01-01

    In open conduit volcanoes, volatile-rich magma continuously enters into the feeding system nevertheless the eruptive activity occurs intermittently. From a practical perspective, the continuous steady input of magma in the feeding system is not able to produce eruptive events alone, but rather surplus of magma inputs are required to trigger the eruptive activity. The greater the amount of surplus of magma within the feeding system, the higher is the eruptive probability.Despite this observation, eruptive potential evaluations are commonly based on the regular magma supply, and in eruptive probability evaluations, generally any magma input has the same weight. Conversely, herein we present a novel approach based on the quantification of surplus of magma progressively intruded in the feeding system. To quantify the surplus of magma, we suggest to process temporal series of measurable parameters linked to the magma supply. We successfully performed a practical application on Mt Etna using the soil CO2 flux recorded over ten years.

  16. Conduit dynamics and post explosion degassing on Stromboli: A combined UV camera and numerical modeling treatment

    McGonigle, A. J. S.; James, M. R.; Tamburello, G.; Aiuppa, A.; Delle Donne, D.; Ripepe, M.

    2016-01-01

    Abstract Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus coda SO2 masses of ≈18–225 kg. Numerical simulations of gas slug ascent show that substantial proportions of the initial gas mass can be distributed into a train of “daughter bubbles” released from the base of the slug, which we suggest, generate the codas, on bursting at the surface. This process could also cause transitioning of slugs into cap bubbles, significantly reducing explosivity. This study is the first attempt to combine high temporal resolution gas flux data with numerical simulations of conduit gas flow to investigate volcanic degassing dynamics. PMID:27478285

  17. Laparoscopic repair for recurrent parastomal hernia of an end stoma using the sandwich technique while preserving an ileal conduit: A case report

    Toshiaki Wada

    2016-01-01

    Conclusion: We herein report a case of recurrent parastomal hernia treated laparoscopically while preserving an ileal conduit using the sandwich technique which combines the keyhole and Sugarbaker techniques. This is a quite rare case report of laparoscopic repair for recurrent parastomal hernia in a patient with an ileal conduit.

  18. Vapor plumes: A neglected aspect of impact cratering

    Melosh, H. J.

    1991-06-01

    When a meteorite or comet strikes the surface of the planet or satellite at typical interplanetary velocities of 10-40 km/sec, the projectile and a quantity of the target body vaporize and expand out of the growing crater at high speed. The crater continues to grow after the vapor plume has formed and the series of ejecta deposits is laid down ballistically while the crater collapses into its final morphology. Although the vapor plume leaves little evidence of its existence in the crater structure of surface deposits, it may play a major role in a number of impact-related processes. The vapor plume expanding away from the site of an impact carries 25-50 percent of the total impact energy. Although the plume's total mass is only a few times the mass of the projectile, its high specific energy content means that it is the fastest and most highly shocked material in the cratering event. The mean velocity of expansion can easily exceed the escape velocity of the target plane, so that the net effect of a sufficiently high-speed impact is to erode material from the planet.

  19. Frictional melting dynamics in the upper conduit: A chemical answer to a complex physical question

    Henton De Angelis, S.; Lavallee, Y.; Kendrick, J. E.; Hornby, A.; von Aulock, F. W.; Clesham, S.; Hirose, T.; Perugini, D.

    2013-12-01

    During volcanic eruptions the generation of frictional heat along the walls of the shallow conduit leads to melting of the rocks along the slip interface. Frictional melting has previously been described as a process out of thermodynamic equilibrium, but upon slip and mingling of the melt batches, homogeneity can be achieved, and may have an h important rheological control on the dynamics of slip. To test melt homogenization in the frictional melt zones of volcanic conduits we performed constant-rate slip experiments under controlled stress conditions using a high-velocity rotary shear apparatus. Volcanic dome samples from three different volcanoes (Volcán De Colima, Soufrière Hills Volcano and Santiaguito Volcano) were investigated. Each sample was subjected to a stress of 1 MPa and slip rate of 1 m/s. For each sample set 5 experiments were conducted: 1) experiment stopped at the onset of melting; 2) experiment stopped on the formation of a full melt layer; 3) experiment stopped after 5m of slip at steady state conditions; 4) experiment stopped after 10m of slip at steady state conditions; 5) experiment stopped after 15m of slip at steady state conditions. We analyzed the resulting proto-melt zones using micron sized X-ray spectroscopy in the high-brightness synchrotron beamline I18 (at Diamond Light Source UK). Particular focus was given to the concentration variance analysis of Rare Earth Elements as their mobilities can be used to precisely quantify the degree and timescale of homogenisation involved during frictional melting. This study refines our understanding of the chemical process of melting and mixing which carry important consequences for the rheological control on the physical dynamics of slip.

  20. Tsivat Basin conduit system persists through two surges, Bering Piedmont Glacier, Alaska

    Fleisher, P.J.; Cadwell, D.H.; Muller, E.H.

    1998-01-01

    The 1993-1995 surge of Bering Glacier, Alaska, occurred in two distinct phases. Phase 1 of the surge began on the eastern sector in July, 1993 and ended in July, 1994 after a powerful outburst of subglacial meltwater into Tsivat Lake basin on the north side of Weeping Peat Island. Within days, jokulhlaup discharge built a 1.5 km2 delta of ice blocks (25-30 m) buried in outwash. By late October 1994, discharge temporarily shifted to a vent on Weeping Peat Island, where a second smaller outburst dissected the island and built two new sandar. During phase 2, which began in spring 1995 and ended within five months, continuous discharge issued from several vents along the ice front on Weeping Peat Island before returining to the Tsivat Basin. Surge related changes include a five- to six-fold increase in meltwater turbidity; the redirection of supercooled water in two ice-contact lakes; and an increase in the rate of glaciolacustrine sedimentation. US Geological Survey aerial photos by Austin Post show large ice blocks in braided channels indicating excessive subglacial discharge in a similar position adjacent to Weeping Peat Island during the 1966-1967 surge. During the subsequent three decades of retreat, the location of ice-marginal, subglacial discharge vents remained aligned on a linear trend that describes the position of a persistent subglacial conduit system. The presence of a major conduit system, possibly stabilized by subglacial bedrock topography, is suggested by: 1) high-level subglacial meltwater venting along the northern side of Weeping Peat Island during the 1966-1967 surge, 2) persistent low-level discharge between surges, and 3) the recurrence of localizing meltwater outbursts associated with both phases of the 1993-1005 surge.

  1. Intra wire resistance and strain affecting the transport properties of Nb3Sn strands in cable-in-conduit conductors

    Zhou, C.

    2014-01-01

    The aim of this thesis work is to arrive at a deeper understanding of the effects of strain and filament fracture on the electric properties of superconducting strands and cable-in-conduit conductors that are subjected to various mechanical loads. Since inter-filamentary current redistribution plays

  2. Assessing the importance of conduit geometry and physical parameters in karst systems using the storm water management model (SWMM)

    Peterson, Eric W.; Wicks, Carol M.

    2006-09-01

    SummaryQuestions about the importance of conduit geometry and about the values of hydraulic parameters in controlling ground-water flow and solute transport through karstic aquifers have remained largely speculative. One goal of this project was to assess the role that the conduit geometry and the hydraulic parameters have on controlling transport dynamics within karstic aquifers. The storm water management model (SWMM) was applied to the Devil's Icebox-Connor's Cave System in central Missouri, USA. Simulations with incremental changes to conduit geometry or hydraulic parameters were performed with the output compared to a calibrated baseline model. Ten percent changes in the length or width of a conduit produced statistically significant different fluid flow responses. The model exhibited minimal sensitivity to slope and infiltration rates; however, slight changes in Manning's roughness coefficient can highly alter the simulated output. Traditionally, the difference in flow dynamics between karstified aquifers and porous media aquifers has led to the idea that modeling of karst aquifers is more difficult and less precise than modeling of porous media aquifers. When evaluated against models for porous media aquifers, SWMM produced results that were as accurate (10% error compared to basecase). In addition, SWMM has the advantage of providing data about local flow. While SWMM may be an appropriate modeling technique for some karstic aquifers, SWMM should not be viewed as a universal solution to modeling karst systems.

  3. Cable-in-conduit superconductors for fusion magnets: electro-magnetic modelling for understanding and optimizing their transport properties

    Rolando, Gabriella

    2013-01-01

    Cable-In-Conduit conductors feature large current-carrying capacity and stability against local and transient heat deposition. As such they are suitable for application in superconducting magnets for nuclear fusion, as the ones of the International Thermonuclear Experimental Reactor (ITER). Due to

  4. A copper vapor laser by using a copper-vapor-complex reaction at a low temperature

    Kano, Toshiyuki; Taniguchi, Hiroshi; Saito, Hiroshi

    1987-01-01

    A copper vapor laser performance by using ametal-vapor-complex reaction (Cu+AlBr3) is reported. The laser operation is obtained at a low temperature without externalheating because of the AlBr3 vapors evaporating at a room temperature. The copper vapor laser using this metal-vapor-complex reaction has an advantage of deposition-free of a metallic copper to the laser tube wall, which is different from the copper halide and the organometallic copper lasers.

  5. What Good is Raman Water Vapor Lidar?

    Whitman, David

    2011-01-01

    Raman lidar has been used to quantify water vapor in the atmosphere for various scientific studies including mesoscale meteorology and satellite validation. Now the international networks of NDACC and GRUAN have interest in using Raman water vapor lidar for detecting trends in atmospheric water vapor concentrations. What are the data needs for addressing these very different measurement challenges. We will review briefly the scientific needs for water vapor accuracy for each of these three applications and attempt to translate that into performance specifications for Raman lidar in an effort to address the question in the title of "What good is Raman water vapor Iidar."

  6. High temperature vapors science and technology

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  7. Tracer Experimental Study of the Main Conveying Conduits of CCl4 Pollutant in the Qiligou Water Supply Resource

    PEI Zong-ping; HAN Bao-ping; LIU Han-hu; LIANG Zhi; ZHOU Dong-lai; ZHU Xue-qiang

    2007-01-01

    The Ordovician karst groundwater in the Qiligou basin is an important water supply source. This groundwater has been seriously contaminated in recent years by CCl4 from a pesticide plant located in the recharge area. The highest concentration of CCl4 in the groundwater is 3909.2 μg/L. Large scale tracer experiments were carried out to study the conveying conduits for CCl4 in the basin on May 1-6, 2005. Nontoxic, edible glucose was used as a tracer and it was detected by spectrophotometric techniques. Well X-61, located near the pesticide plant in the southern recharge area of the basin, was employed for injecting the tracer. Ten wells widely located in the groundwater runoff area were used as observing and sampling wells. The results show that the migration of the pollutants is controlled by the water hydrodynamic field and by the development of karst conduits. The tracer did not enter the up-drainage wells, X-49 and X-47, near the injection point because the water levels at these wells are higher than at the injection point. The adjacent well X-62 is close to the injection site, but the tracer reached the well after eleven hours. Wells X-43, X-59, X-58, YY-1 and X-57, located in the syncline axis runoff area, are respectively 2.5, 3.5, 4.33, 4.38 and 5.44 kilometers from the injection site. The time for initial appearance of tracer was 4, 4, 2, 6 and 4 hours, respectively. The maximum runoff velocity (well X-58) is over two kilometers per hour, indicating that the karst conduits are well developed along the syncline basin axis. These conduits are the main conveying conduits for groundwater and CCl4. Closer wells were not necessarily the first to receive tracer. This shows the inhomogeneity in karst development which causes complex runoff, and pollutant migration, patterns.

  8. Vapor stabilizing surfaces for superhydrophobicity

    Patankar, Neelesh

    2010-11-01

    The success of rough substrates designed for superhydrophobicity relies crucially on the presence of air pockets in the roughness grooves. This air is supplied by the surrounding environment. However, if the rough substrates are used in enclosed configurations, such as in fluidic networks, the air pockets may not be sustained in the roughness grooves. In this work a design approach based on sustaining a vapor phase of the liquid in the roughness grooves, instead of relying on the presence of air, is explored. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling, and dropwise condensation heat transfer, among others.

  9. Active Hydrazine Vapor Sampler (AHVS)

    Young, Rebecca C.; Mcbrearty, Charles F.; Curran, Daniel J.

    1993-01-01

    The Active Hydrazine Vapor Sampler (AHVS) was developed to detect vapors of hydrazine (HZ) and monomethylhydrazine (MMH) in air at parts-per-billion (ppb) concentration levels. The sampler consists of a commercial personal pump that draws ambient air through paper tape treated with vanillin (4-hydroxy-3-methoxybenzaldehyde). The paper tape is sandwiched in a thin cardboard housing inserted in one of the two specially designed holders to facilitate sampling. Contaminated air reacts with vanillin to develop a yellow color. The density of the color is proportional to the concentration of HZ or MMH. The AHVS can detect 10 ppb in less than 5 minutes. The sampler is easy to use, low cost, and intrinsically safe and contains no toxic material. It is most beneficial for use in locations with no laboratory capabilities for instrumentation calibration. This paper reviews the development, laboratory test, and field test of the device.

  10. Internal Water Vapor Photoacoustic Calibration

    Pilgrim, Jeffrey S.

    2009-01-01

    Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The use of an internal calibration eliminates the need for external calibrated reference gases. Commercial applications include an improvement of photoacoustic spectrometers in all fields of use.

  11. Critical points of metal vapors

    Khomkin, A. L., E-mail: alhomkin@mail.ru; Shumikhin, A. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2015-09-15

    A new method is proposed for calculating the parameters of critical points and binodals for the vapor–liquid (insulator–metal) phase transition in vapors of metals with multielectron valence shells. The method is based on a model developed earlier for the vapors of alkali metals, atomic hydrogen, and exciton gas, proceeding from the assumption that the cohesion determining the basic characteristics of metals under normal conditions is also responsible for their properties in the vicinity of the critical point. It is proposed to calculate the cohesion of multielectron atoms using well-known scaling relations for the binding energy, which are constructed for most metals in the periodic table by processing the results of many numerical calculations. The adopted model allows the parameters of critical points and binodals for the vapor–liquid phase transition in metal vapors to be calculated using published data on the properties of metals under normal conditions. The parameters of critical points have been calculated for a large number of metals and show satisfactory agreement with experimental data for alkali metals and with available estimates for all other metals. Binodals of metals have been calculated for the first time.

  12. Water vapor diffusion membrane development

    Tan, M. K.

    1977-01-01

    An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

  13. Interannual and Interdecadal Variability of Atmospheric Water Vapor Transport in the Haihe River Basin

    WEI Jie; LIN Zhao-Hui; XIA Jun; TAO Shi-Yan

    2005-01-01

    The seasonal mean atmospheric precipitable water and water vapor transport over the Haihe River Basin (HRB) in North China with a focus on their interannual to interdecadal variability, and then the relationships of the interannual and interdecadal variability of the water cycle over the HRB to the Pacific Decadal Oscillation (PDO) and El Nino-Southern Oscillation (ENSO) phenomena were investigated using the observational and National Centers for Environmental Prediction (NCEP) reanalysis data. There was a strong interdecadal variability for the water cycle (such as precipitation and water vapor transport) over the region, with an abrupt change occurring mostly in the mid 1970s. The intensity of the East Asian summer monsoon largely affected the atmospheric water vapor transport. Generally, the net meridional convergence of the water vapor flux over the region was relatively large before 1965, and it declined gradually from then on with a further notable decrease since mid 1970s. Zonal water vapor transport was similar to meridional, but with a much smaller magnitude and no noteworthy turning in the mid 1970s. Results also suggested that the wind field played an important role in the water vapor transport over the HRB before the mid 1960s, and the interdecadal variability of the water cycle (precipitation, water vapor transport, etc.) in the summer was related to the PDO; however, interannual variation of the water vapor transport could also be related to the ENSO phenomena.

  14. Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits

    Shan-hui Hsu

    2013-01-01

    Full Text Available Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide (PLA with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.

  15. Construction of a three-dimensional bionic nerve conduit containing two neurotrophic factors with separate delivery systems for the repair of sciatic nerve defects

    Zhiyue Li; Qun Zhao; Ran Bi; Yong Zhuang; Siyin Feng

    2011-01-01

    Previous studies of nerve conduits have investigated numerous properties, such as conduit luminal structure and neurotrophic factor incorporation, for the regeneration of nerve defects. The present study used a poly(lactic-co-glycolic acid) (PLGA) copolymer to construct a three-dimensional (3D) bionic nerve conduit, with two channels and multiple microtubule lumens, and incorporating two neurotrophic factors, each with their own delivery system, as a novel environment for peripheral nerve regeneration. The efficacy of this conduit in repairing a 1.5 cm sciatic nerve defect was compared with PLGA-alone and PLGA-microfilament conduits, and autologous nerve transplantation. Results showed that compared with the other groups, the 3D bionic nerve conduit had the fastest nerve conduction velocity, largest electromyogram amplitude, and shortest electromyogram latency. In addition, the nerve fiber density, myelin sheath thickness and axon diameter were significantly increased, and the recovery rate of the triceps surae muscle wet weight was lowest. These findings suggest that 3D bionic nerve conduits can provide a suitable microenvironment for peripheral nerve regeneration to efficiently repair sciatic nerve defects.

  16. Accurate 3D modeling of Cable in Conduit Conductor type superconductors by X-ray microtomography

    Tiseanu, Ion, E-mail: tiseanu@infim.ro [National Institute for Laser, Plasma and Radiation Physics (INFLPR), Bucharest-Magurele (Romania); Zani, Louis [CEA/Cadarache – Institut de Recherche sur la Fusion Magnetique, St Paul-lez-Durance Cedex (France); Tiseanu, Catalin-Stefan [University of Bucharest, Faculty of Mathematics and Computer Science (Romania); Craciunescu, Teddy; Dobrea, Cosmin [National Institute for Laser, Plasma and Radiation Physics (INFLPR), Bucharest-Magurele (Romania)

    2015-10-15

    Graphical abstract: - Highlights: • Quality controls monitoring of Cable in Conduit Conductor (CICC) by X-ray tomography. • High resolution (≈40 μm) X-ray tomography images of CICC section up to 300 mm long. • Assignment of vast majority of strand trajectories over relevant section of CICC. • Non-invasive accurate measurements of local void fraction statistics. - Abstract: Operation and data acquisition of an X-ray microtomography developed at INFLPR are optimized to produce stacks of 2-D high-resolution tomographic sections of Cable in Conduit Conductor (CICC) type superconductors demanded in major fusion projects. High-resolution images for CCIC samples (486 NbTi&Cu strands of 0.81 mm diameter, jacketed in rectangular stainless steel pipes of 22 × 26 mm{sup 2}) are obtained by a combination of high energy/intensity and small focus spot X-ray source and high resolution/efficiency detector array. The stack of reconstructed slices is then used for quantitative analysis consisting of accurate strand positioning, determination of the local and global void fraction and 3D strand trajectory assignment for relevant fragments of cable (∼300 mm). The strand positioning algorithm is based on the application of Gabor Annular filtering followed by local maxima detection. The local void fraction is extensively mapped by employing local segmentation methods at a space resolution of about 50 sub-cells sized to be relevant to the triplet of triplet twisting pattern. For the strand trajectory assignment part we developed a global algorithm of the linear programing type which provides the vast majority of correct strand trajectories for most practical applications. For carefully manufactured benchmark CCIC samples over 99% of the trajectories are correctly assigned. For production samples the efficiency of the algorithm is around 90%. Trajectory assignment of a high proportion of the strands is a crucial factor for the derivation of statistical properties of the cable

  17. Performances of electrically heated microgroove vaporizers

    2007-01-01

    An electrically heated microgroove vaporizer was proposed. The vaporizer mainly comprised an outer tube, an inner tube and an electrical heater cartridge. Microgrooves were fabricated on the external surface of the inner tube by micro-cutting method,which formed the flow passage for fluid between the external surface of the inner tube and the internal surface of the outer tube.Experiments related to the temperature rise response of water and the thermal conversion efficiency of vaporizer were done to estimate the influences of microgroove's direction, feed flow rate and input voltage on the performances of the vaporizer. The results indicate that the microgroove's direction dominates the vaporizer performance at a lower input voltage. The longitudina lmicrogroove vaporizer exhibits the best performances for the temperature rise response of water and thermal conversion efficiency of vaporizer. For a moderate input voltage, the microgroove's direction and the feed flow rate of water together govern the vaporizer performances. The input voltage becomes the key influencing factor when the vaporizer works at a high input voltage, resulting in the similar performances of longitudinal, oblique and latitudinal microgroove vaporizers.

  18. An in vivo model of in situ implantation using pulmonary valved conduit in large animals under off-pump condition

    WU Hao; XU Zhi-wei; LIU Xian-min; GONG Da; WAN Ju-yi; XU Xiu-fang; ZHOU Zi-fan

    2013-01-01

    Background The application of pulmonary valved conduit to reconstruct the continuity between right ventricles and pulmonary artery is one of the major surgeries.This study aimed to establish an in vivo model of in situ implantation using pulmonary valved conduit in large animals under off-pump condition to validate the long-term effects of artificial pulmonary valved conduit.Methods Domesticate juvenile male sheep and tissue-engineered poorine pulmonary valved conduit were used for the experiment:30 sheep,weighing (15±3) kg (range 13 to 17 kg) were randomly divided into two groups which were all operated under general anesthesia by off-pump surgery (group 1) and left thoracotomy (group 2).Two different off-pump surgical methods were used to perform cannulation in sheep pulmonary artery to replace part of sheep pulmonary artery with pulmonary valved conduit which will work together with sheep pulmonary artery and valves.During the experiments,animal survival,complication rates,operating time and blood loss were recorded to compare the results between groups and to establish a surgical method with minimal invasion,simplicity,safety,and high success rates.Results In group 1,a total of 15 cases of surgeries were performed,in which two sheep died; the operative mortality was 13.3% (2/15).In group 2,a total of 15 cases of surgeries were performed,and the surgical mortality rate was 0 (0/15).The operation time and blood loss in group 2 was significantly better than that in group 1.The postoperative echocardiograms showed that,after the surgeries by these two methods,the blood flows were normal,and the valves can open and close freely.Autopsy after 6 months showed that the inner wall and the valves of pulmonary valved conduit were smooth with no thrombus formation.Conclusion These two off-pump methods are feasible and safe with fewer traumas; but the second method is better and particularly suitable for the establishment of a juvenile animal model.

  19. Photoelectron spectroscopy of phthalocyanine vapors

    Berkowitz, J.

    1979-01-01

    The He(I) photoelectron spectra of several metal phthalocyanines and metal-free phthalocyanine vapor shows that: a sharp peak at 4.99 eV is an artifact due to ionization of atomic He by He(II) radiation; the first phthalocyanine peak (metal-containing or metal-free) occurs at 6.4 eV; and the metal-like d orbitals lie at least 1 to 2 eV deeper, except in the case of Fe. (DLC)

  20. The side-to-side fashion for individual distal coronary anastomosis using venous conduit.

    Kato, Takayoshi; Tsunekawa, Tomohiro; Motoji, Yusuke; Hirakawa, Akihiro; Okawa, Yasuhide; Tomita, Shinji

    2017-04-01

    Regarding to coronary artery bypass grafting (CABG), the end-to-side anastomosis (ESA) has been performed as a gold standard. Recently, the effectiveness of the distal side-to-side anastomosis (SSA) in CABG using internal mammary artery has been reported. The benefit of SSA comparing to ESA also has been disclosed by computing simulation. However, use of SSA by venous conduit for individual CABG has not been reported. In this study, we investigated feasibility of SSA. From January 2013 to October 2014, we conducted 114 CABGs. There were 92 venous distal anastomoses without sequential anastomotic site (61 SSA and 31 ESA). The anastomosis was evaluated before discharge and at 1 year after the procedure by angiography or multi-detector row computed tomographic coronary angiography. The median values for time to anastomosis were 13 min in the two group (p = 0.89). There was no revision of anastomosis in both groups. Additional stitches for hemostasis were required significantly less in SSA than ESA (18.0 vs 45.2 %, respectively, p fashion is easy to perform and maybe beneficial in blood flow pattern.

  1. Measurements of the transverse resistance and eddy current losses in a cable-in-conduit conductor

    Keilin, V. E.; Kovalev, I. A.; Kruglov, S. L.; Lelekhov, S. A.; Il'in, A. A.; Naumov, A. V.; Shcherbakov, V. I.; Shutov, K. A.

    2015-11-01

    In the case of plasma current interruption in tokamaks, the conductor of toroidial field (TF) coils experiences the action of a pulsed decreasing magnetic field (PDMF) parallel to the conductor's axis. To estimate the stability of a cable-in-conduit conductor against the PDMF, a new experimental method to study different types of losses is applied. This method exploits a high sensitivity of temperature and gas pressure to input energy in a closed volume. It allows one to measure hysteresis losses with a rather high accuracy (provided that the rate of change of the PDMF is low) and a sum of hysteresis losses and eddy current losses (when the rate of change of the PDMF is high). An experimental setup to measure the transverse (circumferential) resistance and losses has been developed at the National Research Centre Kurchatov Institute. A Russianmade Nb3Sn conductor intended for the TF coils of the International Thermonuclear Experimental Reactor is subjected to a PDMF with different amplitudes and characteristic times. The electromagnetic time constant and the transverse resistivity of the conductor are experimentally determined. The maximum temperature of strands under the action of the PDMF is calculated.

  2. FEMCAM Analysis of SULTAN Test Results for ITER Nb3SN Cable-conduit Conductors

    Yuhu Zhai, Pierluigi Bruzzone, Ciro Calzolaio

    2013-03-19

    Performance degradation due to filament fracture of Nb3 Sn cable-in-conduit conductors (CICCs) is a critical issue in large-scale magnet designs such as ITER which is currently being constructed in the South of France. The critical current observed in most SULTAN TF CICC samples is significantly lower than expected and the voltage-current characteristic is seen to have a much broader transition from a single strand to the CICC. Moreover, most conductors exhibit the irreversible degradation due to filament fracture and strain relaxation under electromagnetic cyclic loading. With recent success in monitoring thermal strain distribution and its evolution under the electromagnetic cyclic loading from in situ measurement of critical temperature, we apply FEMCAM which includes strand filament breakage and local current sharing effects to SULTAN tested CICCs to study Nb3 Sn strain sensitivity and irreversible performance degradation. FEMCAM combines the thermal bending effect during cool down and the EM bending effect due to locally accumulating Lorentz force during magnet operation. It also includes strand filament fracture and related local current sharing for the calculation of cable n value. In this paper, we model continuous performance degradation under EM cyclic loading based on strain relaxation and the transition broadening upon cyclic loading to the extreme cases seen in SULTAN test data to better quantify conductor performance degradation.

  3. Diminished contractile responses of isolated conduit arteries in two rat models of hypertension.

    Zemancíková, Anna; Török, Jozef

    2013-08-31

    Hypertension is accompanied by thickening of arteries, resulting in marked changes in their passive and active mechanical properties. The aim of this study was to demonstrate that the large conduit arteries from hypertensive individuals may not exhibit enhanced contractions in vitro, as is often claimed. Mechanical responses to vasoconstrictor stimuli were measured under isometric conditions using ring arterial segments isolated from spontaneously hypertensive rats, N(omega)-nitro-L-arginine methyl ester (L-NAME)-treated Wistar rats, and untreated Wistar rats serving as normotensive control. We found that thoracic aortas from both types of hypertensive rats had a greater sensitivity but diminished maximal developed tension in response to noradrenaline, when compared with that from normotensive rats. In superior mesenteric arteries, the sensitivity to noradrenaline was similar in all examined rat groups but in L-NAME-treated rats, these arteries exhibited decreased active force when stimulated with high noradrenaline concentrations, or with 100 mM KCl. These results indicate that hypertension leads to specific biomechanical alterations in diverse arterial types which are reflected in different modifications in their contractile properties.

  4. Morphology and displacement of dunes in a closed-conduit flow

    Franklin, Erick de Moraes

    2016-01-01

    The transport of solid particles entrained by a fluid flow is frequently found in industrial applications. A better knowledge of it, is of importance to improve particle related industrial processes. When shear stresses exerted by the fluid on the bed of particles are bounded to some limits, a mobile layer of particles known as bed-load takes place in which the particles stay in contact with the fixed bed. If it takes place over a non-erodible ground, and if the particle flow rate is small enough, an initial thin continuous layer of particles becomes discontinuous and composed of isolated dunes. We present here an experimental study to understand some features of the dynamics of isolated dunes under a fluid flow using a closed-conduit experimental loop made of transparent material. Acquired data concerns mainly dune morphology and displacement velocity under different conditions: different types of beads (diameters and densities) and different water flow conditions. We observed that an initial pile of beads p...

  5. Apparent glacially induced structural controls on limestone conduit development in Ohio Caverns, United States

    Adrienne M. Watts

    2016-01-01

    Full Text Available Rock discontinuities such as bedding planes and joints are important controls on the form that caves take. We examined structural controls on the development of Ohio Caverns. The cave formed in Devonian limestone underlying a small bedrock knob (Mt. Tabor within the Interior Lowland province, United States. The area has been overridden by continental glaciation multiple times. The bedrock is pervasively fractured, with many curved and wavy near-vertical fractures showing many different orientations. In the case of Ohio Caverns, it appears that the controlling fractures in map view may not be joints sensu stricto, but rather some combination of tensile and shear (mode-1 and mode-2 fractures, probably forming in the regime transition between tensile and shear fracturing. This is easy to envision in a situation with ice advancing over this topographic high, and would result in the curved fractures that are observed in many places in the cave. It can also explain the numerous fracture directions. However, not all fractures are conduit-significant. The cave initiated on or near a single bedding plane, and the cave passages exhibit strong keyhole or plus-sign cross sections. Passage and fracture orientations are inconsistent with regionally expected directions. It is likely that mechanical, hydraulic, and thermal stresses related to glaciation caused the fracturing in Mt. Tabor. The cave then developed on this template according to local hydrologic conditions. This presents a newly documented structural template sub-type for cave development.

  6. Volcanic conduit migration over a basement landslide at Mount Etna (Italy).

    Nicolosi, I; Caracciolo, F D'Ajello; Branca, S; Ventura, G; Chiappini, M

    2014-06-13

    The flanks of volcanoes may slide in response to the loading of the edifice on a weak basement, magma push, and/or to tectonic stress. However, examples of stratovolcanoes emplaced on active landslides are lacking and the possible effects on the volcano dynamics unknown. Here, we use aeromagnetic data to construct a three-dimensional model of the clay-rich basement of Etna volcano (Italy). We provide evidence for a large stratovolcano growing on a pre-existing basement landslide and show that the eastern Etna flank, which slides toward the sea irrespective of volcanic activity, moves coherently with the underlying landslide. The filling of the landslide depression by lava flows through time allows the formation of a stiffness barrier, which is responsible for the long-term migration of the magma pathways from the coast to the present-day Etna summit. These unexpected results provide a new interpretation clue on the causes of the volcanic instability processes and of the mechanisms of deflection and migration of volcanic conduits.

  7. Effect of Surface Pore Structure of Nerve Guide Conduit on Peripheral Nerve Regeneration

    Oh, Se Heang; Kim, Jin Rae; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang

    2013-01-01

    Polycaprolactone (PCL)/Pluronic F127 nerve guide conduits (NGCs) with different surface pore structures (nano-porous inner surface vs. micro-porous inner surface) but similar physical and chemical properties were fabricated by rolling the opposite side of asymmetrically porous PCL/F127 membranes. The effect of the pore structure on peripheral nerve regeneration through the NGCs was investigated using a sciatic nerve defect model of rats. The nerve fibers and tissues were shown to have regenerated along the longitudinal direction through the NGC with a nano-porous inner surface (Nanopore NGC), while they grew toward the porous wall of the NGC with a micro-porous inner surface (Micropore NGC) and, thus, their growth was restricted when compared with the Nanopore NGC, as investigated by immunohistochemical evaluations (by fluorescence microscopy with anti-neurofilament staining and Hoechst staining for growth pattern of nerve fibers), histological evaluations (by light microscopy with Meyer's modified trichrome staining and Toluidine blue staining and transmission electron microscopy for the regeneration of axon and myelin sheath), and FluoroGold retrograde tracing (for reconnection between proximal and distal stumps). The effect of nerve growth factor (NGF) immobilized on the pore surfaces of the NGCs on nerve regeneration was not so significant when compared with NGCs not containing immobilized NGF. The NGC system with different surface pore structures but the same chemical/physical properties seems to be a good tool that is used for elucidating the surface pore effect of NGCs on nerve regeneration. PMID:22871377

  8. Nanopatterned acellular valve conduits drive the commitment of blood-derived multipotent cells

    Di Liddo, Rosa; Aguiari, Paola; Barbon, Silvia; Bertalot, Thomas; Mandoli, Amit; Tasso, Alessia; Schrenk, Sandra; Iop, Laura; Gandaglia, Alessandro; Parnigotto, Pier Paolo; Conconi, Maria Teresa; Gerosa, Gino

    2016-01-01

    Considerable progress has been made in recent years toward elucidating the correlation among nanoscale topography, mechanical properties, and biological behavior of cardiac valve substitutes. Porcine TriCol scaffolds are promising valve tissue engineering matrices with demonstrated self-repopulation potentiality. In order to define an in vitro model for investigating the influence of extracellular matrix signaling on the growth pattern of colonizing blood-derived cells, we cultured circulating multipotent cells (CMC) on acellular aortic (AVL) and pulmonary (PVL) valve conduits prepared with TriCol method and under no-flow condition. Isolated by our group from Vietnamese pigs before heart valve prosthetic implantation, porcine CMC revealed high proliferative abilities, three-lineage differentiative potential, and distinct hematopoietic/endothelial and mesenchymal properties. Their interaction with valve extracellular matrix nanostructures boosted differential messenger RNA expression pattern and morphologic features on AVL compared to PVL, while promoting on both matrices the commitment to valvular and endothelial cell-like phenotypes. Based on their origin from peripheral blood, porcine CMC are hypothesized in vivo to exert a pivotal role to homeostatically replenish valve cells and contribute to hetero- or allograft colonization. Furthermore, due to their high responsivity to extracellular matrix nanostructure signaling, porcine CMC could be useful for a preliminary evaluation of heart valve prosthetic functionality. PMID:27789941

  9. Optimization of lamp arrangement in a closed-conduit UV reactor based on a genetic algorithm.

    Sultan, Tipu; Ahmad, Zeshan; Cho, Jinsoo

    2016-01-01

    The choice for the arrangement of the UV lamps in a closed-conduit ultraviolet (CCUV) reactor significantly affects the performance. However, a systematic methodology for the optimal lamp arrangement within the chamber of the CCUV reactor is not well established in the literature. In this research work, we propose a viable systematic methodology for the lamp arrangement based on a genetic algorithm (GA). In addition, we analyze the impacts of the diameter, angle, and symmetry of the lamp arrangement on the reduction equivalent dose (RED). The results are compared based on the simulated RED values and evaluated using the computational fluid dynamics simulations software ANSYS FLUENT. The fluence rate was calculated using commercial software UVCalc3D, and the GA-based lamp arrangement optimization was achieved using MATLAB. The simulation results provide detailed information about the GA-based methodology for the lamp arrangement, the pathogen transport, and the simulated RED values. A significant increase in the RED values was achieved by using the GA-based lamp arrangement methodology. This increase in RED value was highest for the asymmetric lamp arrangement within the chamber of the CCUV reactor. These results demonstrate that the proposed GA-based methodology for symmetric and asymmetric lamp arrangement provides a viable technical solution to the design and optimization of the CCUV reactor.

  10. Exploring the role of lipids in intercellular conduits: breakthroughs in the pipeline

    Elise eDelage

    2013-12-01

    Full Text Available It has been known for more than a century that most of the plant cells are connected to their neighbors through membranous pores perforating the cell wall, namely plasmodesmata (PDs. The recent discovery of tunneling nanotubes (TNTs, thin membrane bridges established between distant mammalian cells, suggests that intercellular communication mediated through cytoplasmic continuity could be a conserved feature of eukaryotic organisms. Although TNTs differ from PDs in their formation and architecture, both are characterized by a continuity of the plasma membrane between two cells, delimiting a nanotubular channel supported by actin-based cytoskeleton. Due to this unusual membrane organization, lipids are likely to play critical roles in the formation and stability of intercellular conduits like TNTs and PDs, but also in regulating the transfer through these structures. While it is crucial for a better understanding of those fascinating communication highways, the study of TNT lipid composition and dynamics turned out to be extremely challenging. The present review aims to give an overview of the recent findings in this context. We will also discuss some of the promising imaging approaches, which might be the key for future breakthroughs in the field and could also benefit the research on PDs.

  11. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  12. Observation of dispersive shock waves, solitons, and their interactions in viscous fluid conduits

    Anderson, Dalton; Maiden, Michelle; Lowman, Nicholas; Schubert, Marika; Hoefer, Mark

    2016-11-01

    Dispersive shock waves (DSWs) and solitons are fundamental structures in dispersive hydrodynamics, but studies have been severely constrained. Here we report on a novel testbed called the conduit system where one fluid is moved through another via a fluid pipe with virtually no mass diffusion. The interfacial dynamics of this pipe are conservative and are modeled by a scalar, nonlinear, dispersive wave equation, similar to those describing a superfluid. Resultantly, the interfacial waves are effectively dissipationless, which enables high fidelity observations of coherent phenomena such as large amplitude DSWs. Experiments involving solitons, wavebreaking leading to DSWs, and their interactions will be presented. The results include the refraction and absorption of a soliton by a DSW and the refraction of a DSW by a second DSW, resulting in two-phase behavior. Excellent agreement between nonlinear wave averaging, numerics, and laboratory experiments will be presented. The nonlinear wave dynamics observed in this model system have implications for a broad range of other conservative dispersive hydrodynamic systems. NSF.

  13. Results of Buoyancy-gravity Effects in ITER Cable-in- Conduit Conductor with Dual Channel

    Bruzzone, P.; Stepanov, B.; Zanino, R.; Richard, L. Savoldi

    2006-04-01

    The coolant in the ITER cable-in-conduit conductors (CICC) flows at significant higher speed in the central channel than in the strand bundle region due to the large difference of hydraulic impedance. When energy is deposited in the bundle region, e.g. by ac loss or radiation, the heat removal in vertically oriented dual channel CICC with the coolant flowing downward is affected by the reduced density of helium (buoyancy) in the bundle region, which is arising from the temperature gradient due to poor heat exchange between the two channels. At large deposited power, flow stagnation and back-flow can cause in the strand bundle area a slow temperature runaway eventually leading to quench. A new test campaign of the thermal-hydraulic behavior was carried out in the SULTAN facility on an instrumented section of the ITER Poloidal Field Conductor Insert (PFIS). The buoyancy-gravity effect was investigated using ac loss heating, with ac loss in the cable calibrated in separate runs. The extent of upstream temperature increase was explored over a broad range of mass flow rate and deposited power. The experimental behavior is partly reproduced by numerical simulations. The results from the tests are extrapolated to the likely operating conditions of the ITER Toroidal Field conductor with the inboard leg cooled from top to bottom and heat deposited by nuclear radiation from the burning plasma.

  14. The medial temporal lobe-conduit of parallel connectivity: a model for attention, memory, and perception.

    Mozaffari, Brian

    2014-01-01

    Based on the notion that the brain is equipped with a hierarchical organization, which embodies environmental contingencies across many time scales, this paper suggests that the medial temporal lobe (MTL)-located deep in the hierarchy-serves as a bridge connecting supra- to infra-MTL levels. Bridging the upper and lower regions of the hierarchy provides a parallel architecture that optimizes information flow between upper and lower regions to aid attention, encoding, and processing of quick complex visual phenomenon. Bypassing intermediate hierarchy levels, information conveyed through the MTL "bridge" allows upper levels to make educated predictions about the prevailing context and accordingly select lower representations to increase the efficiency of predictive coding throughout the hierarchy. This selection or activation/deactivation is associated with endogenous attention. In the event that these "bridge" predictions are inaccurate, this architecture enables the rapid encoding of novel contingencies. A review of hierarchical models in relation to memory is provided along with a new theory, Medial-temporal-lobe Conduit for Parallel Connectivity (MCPC). In this scheme, consolidation is considered as a secondary process, occurring after a MTL-bridged connection, which eventually allows upper and lower levels to access each other directly. With repeated reactivations, as contingencies become consolidated, less MTL activity is predicted. Finally, MTL bridging may aid processing transient but structured perceptual events, by allowing communication between upper and lower levels without calling on intermediate levels of representation.

  15. The Medial Temporal Lobe – Conduit of Parallel Connectivity: A model for Attention, Memory, and Perception.

    Brian B. Mozaffari

    2014-11-01

    Full Text Available Based on the notion that the brain is equipped with a hierarchical organization, which embodies environmental contingencies across many time scales, this paper suggests that the medial temporal lobe (MTL – located deep in the hierarchy – serves as a bridge connecting supra to infra – MTL levels. Bridging the upper and lower regions of the hierarchy provides a parallel architecture that optimizes information flow between upper and lower regions to aid attention, encoding, and processing of quick complex visual phenomenon. Bypassing intermediate hierarchy levels, information conveyed through the MTL ‘bridge’ allows upper levels to make educated predictions about the prevailing context and accordingly select lower representations to increase the efficiency of predictive coding throughout the hierarchy. This selection or activation/deactivation is associated with endogenous attention. In the event that these ‘bridge’ predictions are inaccurate, this architecture enables the rapid encoding of novel contingencies. A review of hierarchical models in relation to memory is provided along with a new theory, Medial-temporal-lobe Conduit for Parallel Connectivity (MCPC. In this scheme, consolidation is considered as a secondary process, occurring after a MTL-bridged connection, which eventually allows upper and lower levels to access each other directly. With repeated reactivations, as contingencies become consolidated, less MTL activity is predicted. Finally, MTL bridging may aid processing transient but structured perceptual events, by allowing communication between upper and lower levels without calling on intermediate levels of representation.

  16. The Society of Thoracic Surgeons Clinical Practice Guidelines on Arterial Conduits for Coronary Artery Bypass Grafting.

    Aldea, Gabriel S; Bakaeen, Faisal G; Pal, Jay; Fremes, Stephen; Head, Stuart J; Sabik, Joseph; Rosengart, Todd; Kappetein, A Pieter; Thourani, Vinod H; Firestone, Scott; Mitchell, John D

    2016-02-01

    Internal thoracic arteries (ITAs) should be used to bypass the left anterior descending (LAD) artery when bypass of the LAD is indicated (class of recommendation [COR] I, level of evidence [LOE] B). As an adjunct to left internal thoracic artery (LITA), a second arterial graft (right ITA or radial artery [RA]) should be considered in appropriate patients (COR IIa, LOE B). Use of bilateral ITAs (BITAs) should be considered in patients who do not have an excessive risk of sternal complications (COR IIa, LOE B). To reduce the risk of sternal infection with BITA, skeletonized grafts should be considered (COR IIa, LOE B), smoking cessation is recommended (COR I, LOE C), glycemic control should be considered (COR IIa, LOE B), and enhanced sternal stabilization may be considered (COR IIb, LOE C). As an adjunct to LITA to LAD (or in patients with inadequate LITA grafts), use of a RA graft is reasonable when grafting coronary targets with severe stenoses (COR IIa, LOE: B). When RA grafts are used, it is reasonable to use pharmacologic agents to reduce acute intraoperative and perioperative spasm (COR IIa, LOE C). The right gastroepiploic artery may be considered in patients with poor conduit options or as an adjunct to more complete arterial revascularization (COR IIb, LOE B). Use of arterial grafts (specific targets, number, and type) should be a part of the discussion of the heart team in determining the optimal approach for each patient (COR I, LOE C).

  17. Effect of surface pore structure of nerve guide conduit on peripheral nerve regeneration.

    Oh, Se Heang; Kim, Jin Rae; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Lee, Jin Ho

    2013-03-01

    Polycaprolactone (PCL)/Pluronic F127 nerve guide conduits (NGCs) with different surface pore structures (nano-porous inner surface vs. micro-porous inner surface) but similar physical and chemical properties were fabricated by rolling the opposite side of asymmetrically porous PCL/F127 membranes. The effect of the pore structure on peripheral nerve regeneration through the NGCs was investigated using a sciatic nerve defect model of rats. The nerve fibers and tissues were shown to have regenerated along the longitudinal direction through the NGC with a nano-porous inner surface (Nanopore NGC), while they grew toward the porous wall of the NGC with a micro-porous inner surface (Micropore NGC) and, thus, their growth was restricted when compared with the Nanopore NGC, as investigated by immunohistochemical evaluations (by fluorescence microscopy with anti-neurofilament staining and Hoechst staining for growth pattern of nerve fibers), histological evaluations (by light microscopy with Meyer's modified trichrome staining and Toluidine blue staining and transmission electron microscopy for the regeneration of axon and myelin sheath), and FluoroGold retrograde tracing (for reconnection between proximal and distal stumps). The effect of nerve growth factor (NGF) immobilized on the pore surfaces of the NGCs on nerve regeneration was not so significant when compared with NGCs not containing immobilized NGF. The NGC system with different surface pore structures but the same chemical/physical properties seems to be a good tool that is used for elucidating the surface pore effect of NGCs on nerve regeneration.

  18. Peripheral nerve regeneration within an asymmetrically porous PLGA/Pluronic F127 nerve guide conduit.

    Oh, Se Heang; Kim, Jun Ho; Song, Kyu Sang; Jeon, Byeong Hwa; Yoon, Jin Hwan; Seo, Tae Beom; Namgung, Uk; Lee, Il Woo; Lee, Jin Ho

    2008-04-01

    Asymmetrically porous tubes with selective permeability and hydrophilicity as nerve guide conduits (NGCs) were fabricated using poly(lactic-co-glycolic acid) (PLGA) and Pluronic F127 by a modified immersion precipitation method. The inner surface of the tube had nano-size pores ( approximately 50nm) which can effectively prevent from fibrous tissue infiltration but permeate nutrients and retain neurotrophic factors, while the outer surface had micro-size pores ( approximately 50microm) which can allow vascular ingrowth for effective supply of nutrients into the tube. From the animal study using a rat model, the hydrophilized PLGA/F127 (3wt%) tube showed better nerve regeneration behavior than the control silicone or hydrophobic PLGA tubes, as investigated by immunohistochemical observation (by fluorescent microscopy with anti-neurofilament staining), histological observations (by light microscopy with toluidine blue staining and transmission electron microscopy), and electrophysiological evaluation (by compound muscle action potential measurement). This is probably owing to the effective permeation of nutrients and prevention of fibrous scar tissue invasion as well as the good mechanical strength of the tube to maintain a stable support structure for the nerve regeneration.

  19. Vapor Pressure Data Analysis and Statistics

    2016-12-01

    Army Edgewood Chemical Biological Center P vapor pressure (Pa) p vapor pressure (Torr) R ideal gas constant RVX O-isobutyl-S-[2(diethylamino...Respondents should be aware that notwithstanding any other provision of law , no person shall be subject to any penalty for failing to comply with a...1-Hexadecanol Vapor Pressure Data from Kemme and Kreps11 .......................................10 2. Antoine Constants (Equation 3), Standard

  20. Voltage spike observation in superconducting cable-in-conduit conductor under ramped magnetic fields. Pt. 1: Experiment

    Sangkwon Jeong; Schultz, J.H.; Takayasu, Makoto; Vysotsky, Vitaly; Michael, P.C. [Massachusetts Inst. of Technology, Plasma Fusion Center, Cambridge, MA (United States); Warnes, William [Oregan State Univ., Corvallis, OR (United States); Shen, Stewart [Lawrence Livermore National Lab., Livermore, CA (United States)

    1997-06-01

    A 27-strand hybrid superconducting cable-in-conduit conductor (CICC) was fabricated and tested under quickly-ramped high magnetic fields. When the field increased linearly on the CICC, the voltage signal showed several intermittent spikes before it quenched. This paper describes an observation of peculiar voltage spikes during these ramp-rate limitation experiments. The voltage spikes are interpreted as quench precursors and understood as current redistribution events within the local cable inside the conduit. A quantitative correlation is obtained for the magnetic field at which the first voltage spike occurs during ramping fields. The non-uniform current distribution among the strands and the induced loop current in the cable, which is generated by ramped fields, are found to be responsible for the voltage spikes. (author)

  1. A numerical program for steady-state flow of magma-gas mixtures through vertical eruptive conduits

    Mastin, Larry G.; Ghiorso, Mark S.

    2000-01-01

    This report presents a model that calculates flow properties (pressure, vesicularity, and some 35 other parameters) as a function of vertical position within a volcanic conduit during a steady-state eruption. The model idealizes the magma-gas mixture as a single homogeneousfluid and calculates gas exsolution under the assumption of equilibrium conditions. These are the same assumptions on which classic conduit models (e.g. Wilson and Head, 1981) have been based. They are most appropriate when applied to eruptions of rapidly ascending magma (basaltic lava-fountain eruptions, and Plinian or sub-Plinian eruptions of intermediate or silicic magmas) that contains abundant nucleation sites (microlites, for example) for bubble growth.

  2. Use of short half-life cosmogenic isotopes to quantify sediment mixing and transport in karst conduits

    Paylor, R.

    2011-12-01

    Particulate inorganic carbon (PIC) transport and flux in karst aquifers is poorly understood. Methods to quantify PIC flux are needed in order to account for total inorganic carbon removal (chemical plus mechanical) from karst settings. Quantifying PIC flux will allow more accurate calculations of landscape denudation and global carbon sink processes. The study concentrates on the critical processes of the suspended sediment component of mass flux - surface soil/stored sediment mixing, transport rates and distance, and sediment storage times. The primary objective of the study is to describe transport and mixing with the resolution of single storm-flow events. To quantify the transport processes, short half-life cosmogenic isotopes are utilized. The isotopes 7Be (t1/2 = 53d) and 210Pb (t1/2 = 22y) are the primary isotopes measured, and other potential isotopes such as 137Cs and 241Am are investigated. The study location is at Mammoth Cave National Park within the Logsdon River watershed. The Logsdon River conduit is continuously traversable underground for two kilometers. Background levels and input concentrations of isotopes are determined from soil samples taken at random locations in the catchment area, and suspended sediment collected from the primary sinking stream during a storm event. Suspended sediment was also collected from the downstream end of the conduit during the storm event. After the storm flow receded, fine sediment samples were taken from the cave stream at regular intervals to determine transport distances and mixing ratios along the conduit. Samples were analyzed with a Canberra Industries gamma ray spectrometer, counted for 24 hours to increase detection of low radionuclide activities. The measured activity levels of radionuclides in the samples were adjusted for decay from time of sampling using standard decay curves. The results of the study show that surface sediment mixing, transport and storage in karst conduits is a dynamic but

  3. Repairing nerve gaps by vein conduits filled with lipoaspirate-derived entire adipose tissue hinders nerve regeneration.

    Papalia, Igor; Raimondo, Stefania; Ronchi, Giulia; Magaudda, Ludovico; Giacobini-Robecchi, Maria G; Geuna, Stefano

    2013-05-01

    In spite of great recent advancements, the definition of the optimal strategy for bridging a nerve defect, especially across long gaps, still remains an open issue since the amount of autologous nerve graft material is limited while the outcome after alternative tubulization techniques is often unsatisfactory. The aim of this study was to investigate a new tubulization technique based on the employment of vein conduits filled with whole subcutaneous adipose tissue obtained by lipoaspiration. In adult rats, a 1cm-long defect of the left median nerve was repaired by adipose tissue-vein-combined conduits and compared with fresh skeletal muscle tissue-vein-combined conduits and autologous nerve grafts made by the excised nerve segment rotated by 180°. Throughout the postoperative period, functional recovery was assessed using the grasping test. Regenerated nerve samples were withdrawn at postoperative month-6 and processed for light and electron microscopy and stereology of regenerated nerve fibers. Results showed that functional recovery was significantly slower in the adipose tissue-enriched group in comparison to both control groups. Light and electron microscopy showed that a large amount of adipose tissue was still present inside the vein conduits at postoperative month-6. Stereology showed that all quantitative morphological predictors analyzed performed significantly worse in the adipose tissue-enriched group in comparison to the two control groups. On the basis of this experimental study in the rat, the use of whole adipose tissue for tissue engineering of peripheral nerves should be discouraged. Pre-treatment of adipose tissue aimed at isolating stromal vascular fraction and/or adipose derived stem/precursor cells should be considered a fundamental requisite for nerve repair.

  4. Recurrent transitional cell carcinoma in the anastomotic site of ileal conduit and ureter: a report of two cases

    Kang, Joon Won; Kim, Seung Hyup [Seoul National Univ. College of Medicine and the Institute of Radiation MEDICINE, Seoul (Korea, Republic of); Seong, Chang Kyu [Kyungpook National Univ. College of Medicine, Kyungsan(Korea, Republic of)

    2001-01-01

    The authors report two cases of recurrent transitional cell carcinoma at the anastomotic site of the ileal conduit and ureter after total cystectomy. In one patient, a recurrent tumor was also found in the distal ureter which had not been removed during previous nephrectomy. At follow up, the patients presented with gross hematuria or hydronephrosis, and the presence of mass lesions was demostarted by intravenous urography, antegrade pyelography, and/or loopography. Transitional cell carcinoma was diagnosed by surgery and pathologic examination.

  5. A review of bioactive release from nerve conduits as a neurotherapeutic strategy for neuronal growth in peripheral nerve injury.

    Ramburrun, Poornima; Kumar, Pradeep; Choonara, Yahya E; Bijukumar, Divya; du Toit, Lisa C; Pillay, Viness

    2014-01-01

    Peripheral nerve regeneration strategies employ the use of polymeric engineered nerve conduits encompassed with components of a delivery system. This allows for the controlled and sustained release of neurotrophic growth factors for the enhancement of the innate regenerative capacity of the injured nerves. This review article focuses on the delivery of neurotrophic factors (NTFs) and the importance of the parameters that control release kinetics in the delivery of optimal quantities of NTFs for improved therapeutic effect and prevention of dose dumping. Studies utilizing various controlled-release strategies, in attempt to obtain ideal release kinetics, have been reviewed in this paper. Release strategies discussed include affinity-based models, crosslinking techniques, and layer-by-layer technologies. Currently available synthetic hollow nerve conduits, an alternative to the nerve autografts, have proven to be successful in the bridging and regeneration of primarily the short transected nerve gaps in several patient cases. However, current research emphasizes on the development of more advanced nerve conduits able to simulate the effectiveness of the autograft which includes, in particular, the ability to deliver growth factors.

  6. A Review of Bioactive Release from Nerve Conduits as a Neurotherapeutic Strategy for Neuronal Growth in Peripheral Nerve Injury

    Poornima Ramburrun

    2014-01-01

    Full Text Available Peripheral nerve regeneration strategies employ the use of polymeric engineered nerve conduits encompassed with components of a delivery system. This allows for the controlled and sustained release of neurotrophic growth factors for the enhancement of the innate regenerative capacity of the injured nerves. This review article focuses on the delivery of neurotrophic factors (NTFs and the importance of the parameters that control release kinetics in the delivery of optimal quantities of NTFs for improved therapeutic effect and prevention of dose dumping. Studies utilizing various controlled-release strategies, in attempt to obtain ideal release kinetics, have been reviewed in this paper. Release strategies discussed include affinity-based models, crosslinking techniques, and layer-by-layer technologies. Currently available synthetic hollow nerve conduits, an alternative to the nerve autografts, have proven to be successful in the bridging and regeneration of primarily the short transected nerve gaps in several patient cases. However, current research emphasizes on the development of more advanced nerve conduits able to simulate the effectiveness of the autograft which includes, in particular, the ability to deliver growth factors.

  7. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture di...

  8. THE PENETRATION OF VESICANT VAPORS INTO HUMAN SKIN.

    Nagy, S M; Golumbic, C; Stein, W H; Fruton, J S; Bergmann, M

    1946-07-20

    Analytical methods which are accurate to about 1 per cent have been developed for the determination of small amounts (ca. 500 gamma) of bis(beta-chloroethyl)-sulfide (H), ethyl-bis(beta-chloroethyl)amine (EBA), tris(beta-chloroethyl)amine (TBA), beta-chloroethyl-benzylsulfide (benzyl-H), and beta-chloroethyl-ethylsulfide (ethyl-H). The determinations are made by micro titration of the HCl liberated upon complete hydrolysis of the vesicants. A description is given of an apparatus suitable for applying vapors of vesicants to unit areas of skin. A very precise and reproducible micropipetting technique is described for the introduction of the vesicants into the penetration apparatus. By means of this penetration apparatus studies have been made of several factors which may influence the rate at which vesicant vapors penetrate into skin. Model experiments have been performed in which H was allowed to vaporize and the vapor was absorbed on a surface such as that of diethylene glycol or vaseline. It has been found that if the surface of liquid H is increased by spreading the agent on filter paper, the rate of evaporation is markedly increased. Furthermore, if the vapor is agitated by means of a magnetically driven fan, the rate of absorption by diethylene glycol is greatly accelerated. With vaseline as the absorbing surface it has been found that the area of the absorbing surface has an effect on the rate of absorption of H vapor. More H is absorbed by vaseline spread on filter paper to give a rough surface than is absorbed by a smooth film of vaseline. Measurements of the rate of penetration into human skin of H, EBA, TBA, benzyl-H, and ethyl-H vapors have been performed at 21-23 degrees C. and 30-31 degrees C. by means of the penetration apparatus described in this paper. The measurements were carred out on human volunteers under conditions of controlled temperature and humidity. When human skin is exposed to air saturated with H vapor, the H penetrates the skin of the

  9. Self-deactivation of water vapor - Role of the dimer

    Zuckerwar, A. J.

    1984-01-01

    A phenomenological multiple-relaxation theory of the deactivation rate constant for the nu-2 (1 - 0) bending mode of water vapor is presented which incorporates the role not only of the excited monomer but also of the bound molecular complex, in particular the dimer. The deactivation takes place by means of three parallel processes: (1) collisional deexcitation of the excited monomer, (2) a two-step reaction involving association and spontaneous redissociation of an H2O collision complex, and (3) spontaneous dissociation of the stably bound H2O dimer. Oxygen, but not nitrogen or argon, serves as an effective chaperon for the formation of the activated complex. This observation explains the impurity dependence of the self-deactivation rate constant of water vapor. Analysis of an ultrasonic absorption peak based on the third process yields values for the standard entropy and enthalpy of dissociation of the stably bound H2O dimer.

  10. Microcomponents manufacturing for precise devices by copper vapor laser

    Gorny, Sergey; Nikonchuk, Michail O.; Polyakov, Igor V.

    2001-06-01

    This paper presents investigation results of drilling of metal microcomponents by copper vapor laser. The laser consists of master oscillator - spatial filter - amplifier system, electronics switching with digital control of laser pulse repetition rate and quantity of pulses, x-y stage with computer control system. Mass of metal, removed by one laser pulse, is measured and defined by means of diameter and depth of holes. Interaction of next pulses on drilled material is discussed. The difference between light absorption and metal evaporation processes is considered for drilling and cutting. Efficiency of drilling is estimated by ratio of evaporation heat and used laser energy. Maximum efficiency of steel cutting is calculated with experimental data of drilling. Applications of copper vapor laser for manufacturing is illustrated by such microcomponents as pin guide plate for printers, stents for cardio surgery, encoded disks for security systems and multiple slit masks for spectrophotometers.

  11. Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

    Dora M. Paolucci

    2011-03-01

    Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

  12. Interplay of vapor adsorption and liquid imbibition in nanoporous Vycor glass

    Kiepsch, Sebastian; Pelster, Rolf

    2016-04-01

    We have studied the kinetics of spontaneous capillary rise and of the concurrent vapor adsorption in nanoporous, monolithic samples of Vycor glass with a mean pore diameter of 7.5 nm. As liquids, we have chosen n -alcohols (n =4 -10 ) whose vapor pressures at room temperature range from p0=965 Pa down to p0=0.743 Pa. Dielectric measurements allow us to achieve spatial selectivity to predefined parts of the porous Vycor glass. In this way, we are able to measure the overall uptake of molecules as well as vapor adsorption from the surroundings in unfilled parts of the pore network, i.e., above the liquid menisci of the rising imbibition front. We show that the latter process is unaltered compared to free adsorption in samples suspended above a liquid reservoir. Only at low vapor pressures, i.e., for long alcohols, vapor adsorption can be neglected and the capillary rise follows the theoretical predictions of the Lucas-Washburn √{t } law. The more volatile the alcohol, the more important the additional adsorption of molecules becomes. We show that the overall filling process in the pore network is well described by a superposition of the Lucas-Washburn law and the measured vapor adsorption. In addition, the experiments give insight into the vapor diffusion dynamics in the porous matrix.

  13. Seasonal Trends in Stratospheric Water Vapor as Derived from SAGE II Data

    Roell, Marilee M.; Fu, Rong

    2008-01-01

    Published analysis of HALOE and Boulder balloon measurements of water vapor have shown conflicting trends in stratospheric water vapor for the periods of 1981 through 2005. Analysis of the SAGE II monthly mean water vapor data filtered for large aerosol events for time periods from 1985-1991, 1995-1999, and 2000-2005 have shown a globally decreasing water vapor trend at 17.5km. Seasonal analysis for these three time periods show a decreasing trend in water vapor at 17.5km for the winter and spring seasons. The summer and autumn seasonal analysis show a decreasing trend from 1985-2005, however, there is a increasing trend in water vapor at 17.5km for these seasons during 1995-2005. Latitude vs height seasonal analysis show a decreasing trend in the lower stratosphere between 20S - 20N for the autumn season, while at the latitudes of 30-50S and 30-50N there is an increasing trend in water vapor at heights up to 15km for that season. Comparison with regions of monsoon activity (Asian and North American) show that the Asian monsoon region had some effect on the lower stratospheric moistening in 1995-1999, however, for the time period of 2000-2005, there was no change in the global trend analysis due to either monsoon region. This may be due to the limitations of the SAGE II data from 2000-2005.

  14. Use of GDNF-Releasing Nanofiber Nerve Guide Conduits for the Repair of Conus Medullaris/Cauda Equina Injury in the Nonhuman Primate

    2013-12-01

    load the biodegradable fibers to the lumen of the nerve guidance conduits (NGCs) as shown in Fig. 1. This new configuration aims to increase the...available surface area of aligned fibers to provide even more directional guidance to the regenerating axons. With our previous- generation design...longitudinally aligned fibers lined only the innermost surface of the conduit wall. This new nanofiber NGC design provides a greater number of

  15. From rock to magma and back again: The evolution of temperature and deformation mechanism in conduit margin zones

    Heap, Michael J.; Violay, Marie; Wadsworth, Fabian B.; Vasseur, Jérémie

    2017-04-01

    Explosive silicic volcanism is driven by gas overpressure in systems that are inefficient at outgassing. The zone at the margin of a volcanic conduit-thought to play an important role in the outgassing of magma and therefore pore pressure changes and explosivity-is the boundary through which heat is exchanged from the hot magma to the colder country rock. Using a simple heat transfer model, we first show that the isotherm for the glass transition temperature (whereat the glass within the groundmass transitions from a glass to an undercooled liquid) moves into the country rock when the magma within the conduit can stay hot, or into the conduit when the magma is quasi-stagnant and cools (on the centimetric scale over days to months). We then explore the influence of a migrating viscous boundary on compactive deformation micromechanisms in the conduit margin zone using high-pressure (effective pressure of 40 MPa), high-temperature (up to 800 °C) triaxial deformation experiments on porous andesite. Our experiments show that the micromechanism facilitating compaction in andesite is localised cataclastic pore collapse at all temperatures below the glass transition of the amorphous groundmass glass Tg (i.e., rock). In this regime, porosity is only reduced within the bands of crushed pores; the porosity outside the bands remains unchanged. Further, the strength of andesite is a positive function of temperature below the threshold Tg due to thermal expansion driven microcrack closure. The micromechanism driving compaction above Tg (i.e., magma) is the distributed viscous flow of the melt phase. In this regime, porosity loss is distributed and is accommodated by the widespread flattening and closure of pores. We find that viscous flow is much more efficient at reducing porosity than cataclastic pore collapse, and that it requires stresses much lower than those required to form bands of crushed pores. Our study therefore highlights that temperature excursions can result in a

  16. Cellulose/soy protein composite-based nerve guidance conduits with designed microstructure for peripheral nerve regeneration

    Gan, Li; Zhao, Lei; Zhao, Yanteng; Li, Ke; Tong, Zan; Yi, Li; Wang, Xiong; Li, Yinping; Tian, Weiqun; He, Xiaohua; Zhao, Min; Li, Yan; Chen, Yun

    2016-10-01

    Objective. The objective of this work was to develop nerve guidance conduits from natural polymers, cellulose and soy protein isolate (SPI), by evaluating the effects of cellulose/SPI film-based conduit (CSFC) and cellulose/SPI sponge-based conduit (CSSC) on regeneration of nerve defects in rats. Approach. CSFC and CSSC with the same chemical components were fabricated from cellulose and SPI. Effects of CSSC and CSFC on regeneration of the defective nerve were comparatively investigated in rats with a 10 mm long gap in sciatic nerve. The outcomes of peripheral nerve repair were evaluated by a combination of electrophysiological assessment, Fluoro-Gold retrograde tracing, double NF200/S100 immunofluorescence analysis, toluidine blue staining, and electron microscopy. The probable molecular mechanism was investigated using quantitative real-time PCR (qPCR) analysis. Main results. Compared with CSFC, CSSC had 2.69 times higher porosity and 5.07 times higher water absorption, thus ensuring much higher permeability. The nerve defects were successfully bridged and repaired by CSSC and CSFC. Three months after surgery, the CSSC group had a higher compound muscle action potential amplitude ratio, a higher percentage of positive NF200 and S100 staining, and a higher axon diameter and myelin sheath thickness than the CSFC group, showing the repair efficiency of CSSC was higher than that of CSFC. qPCR analysis indicated the mRNA levels of nerve growth factor, IL-10, IL-6, and growth-associated protein 43 (GAP-43) were higher in the CSSC group. This also indicated that there was better nerve repair with CSSC due to the higher porosity and permeability of CSSC providing a more favourable microenvironment for nerve regeneration than CSFC. Significance. A promising nerve guidance conduit was developed from cellulose/SPI sponge that showed potential for application in the repair of nerve defect. This work also suggests that nerve guidance conduits with better repair efficiency

  17. The dance of meaning

    Rasmussen, Ole Elstrup

    2005-01-01

    competence, qualifications, sense making, reasoning, meaning, intentionality, interpersonal relationship......competence, qualifications, sense making, reasoning, meaning, intentionality, interpersonal relationship...

  18. Evidence for the development of permeability anisotropy in lava domes and volcanic conduits

    Farquharson, Jamie I.; Heap, Michael J.; Lavallée, Yan; Varley, Nick R.; Baud, Patrick

    2016-09-01

    The ease at which exsolving volatiles can migrate though magma and outgas influences the explosivity of a volcanic eruption. Volcanic rocks often contain discrete discontinuities, providing snapshots of strain localisation processes that occur during magma ascent and extrusion. Whether these features comprise pathways for or barriers to fluid flow is thus of relevance for volcanic eruption and gas emission modelling. We report here on nine discontinuity-bearing andesite blocks collected from Volcán de Colima, Mexico. We present a systematic porosity and permeability study of fifty cores obtained from the blocks collected, and interpret the genetic processes of the discontinuities through detailed microstructural examination. Bands in pumiceous blocks were inferred to be relicts of inhomogeneous bubble expansion which, despite significantly increasing porosity, do not markedly affect permeability. Other discontinuities in our blocks are interpreted to be shear strain-induced flow banding, cavitation porosity, and/or variably healed fractures. In each of these cases, an increase in permeability (up to around three orders of magnitude) was measured relative to the host material. A final sample contained a band of lower porosity than the host rock, characterised by variably infilled pores. In this case, the band was an order of magnitude less permeable than the host rock, highlighting the complex interplay between dilatant and densifying processes in magma. We therefore present evidence for significant permeability anisotropy within the conduit and/or dome of a volcanic system. We suggest that the abundance and distribution of strain localisation features will influence the escape or entrapment of volatiles and therefore the evolution of pore pressure within active volcanic systems. Using a simple upscaling model, we illustrate the relative importance of permeable structures over different lengthscales. Strain localisation processes resulting in permeability

  19. Thermal hydraulic characteristics study of prototype NET and CEA cable-in-conduit conductors (CICCs)

    Maekawa, Ryuji

    1995-10-31

    The thermal hydraulic characteristics of low temperature helium in a Cable-in-Conduit Conductor (CICC) significantly affects the overall design and performance of the associated large scale superconducting magnet system. It is essential to understand the transient and steady state behavior of the helium in the conductor. Throughout the development of CICCs, the reduction of flow impedance has been one of the key factors to improving the overall pressure drop. The newly developed CICC for the ITER project has a hybrid cooling scheme: a central channel that is surrounded by bundles, for which the thermal hydraulic characteristics are not well understood. This thesis describes an experimental and analytical investigation of thermal hydraulic characteristics of low temperature helium in conventional and hybrid CICCS. Pressure drop measurements for both NET and CEA conductors have been conducted, using low temperature helium and liquid nitrogen to obtain a range of Reynolds numbers. The results are correlated with classical friction factor and Reynolds number analysis. The flow impedance reduction of the CEA conductor is described by measures of a developed flow model. Thermally induced flow in the CEA conductor has been studied with an inductive heating method. The induced velocity in the central channel is measured by a Pitot tube with steady state Reynolds number up to {approximately}7000. The transient pressure wave propagation has been recorded with pressure transducers placed equally along the conductor. The supercritical helium temperature in the central channel has been measured with the thermometer probe. However, the reduction of the central channel area significantly affects the overall thermal hydraulic characteristics of the conductor. The results suggest the importance of the central channel. A transient heat transfer experiment studied the.transverse heat transfer mechanism in the CEA conductor. The temperatures in the central channel and bundle region

  20. Time scales of foam stability in shallow conduits: Insights from analogue experiments

    Spina, L.; Scheu, B.; Cimarelli, C.; Arciniega-Ceballos, A.; Dingwell, D. B.

    2016-10-01

    Volcanic systems can exhibit periodical trends in degassing activity, characterized by a wide range of time scales. Understanding the dynamics that control such periodic behavior can provide a picture of the processes occurring in the feeding system. Toward this end, we analyzed the periodicity of outgassing in a series of decompression experiments performed on analogue material (argon-saturated silicone oil plus glass beads/fibers) scaled to serve as models of basaltic magma. To define the effects of liquid viscosity and crystal content on the time scale of outgassing, we investigated both: (1) pure liquid systems, at differing viscosities (100 and 1000 Pa s), and (2) particle-bearing suspensions (diluted and semidiluted). The results indicate that under dynamic conditions (e.g., decompressive bubble growth and fluid ascent within the conduit), the periodicity of foam disruption may be up to several orders of magnitude less than estimates based on the analysis of static conditions. This difference in foam disruption time scale is inferred to result from the contribution of bubble shear and bubble growth to inter-bubble film thinning. The presence of particles in the semidiluted regime is further linked to shorter bubble bursting times, likely resulting from contributions of the presence of a solid network and coalescence processes to the relative increase in bubble breakup rates. Finally, it is argued that these experiments represent a good analogue of gas-piston activity (i.e., the periodical rise-and-fall of a basaltic lava lake surface), implying a dominant role for shallow foam accumulation as a source process for these phenomena.

  1. Fibronectin provides a conduit for fibroblast transmigration from collagenous stroma into fibrin clot provisional matrix.

    Greiling, D; Clark, R A

    1997-04-01

    After injury, the wound space is filled with a fibrin/fibronectin clot containing growth factors released by platelets and monocytes. In response to these factors, fibroblasts migrate into the fibrin clot and contribute to the formation of granulation tissue. The functional mechanisms allowing fibroblasts to leave the collagenous matrix of normal connective tissue and invade the provisional matrix of the fibrin clot have not been fully defined. To investigate these mechanisms we established a new in vitro model which simulates specific aspects of early wound healing, that is, the migration of fibroblasts from a three-dimensional collagen matrix into a fibrin clot. This transmigration could be induced by physiological concentrations of platelet releasate or platelet-derived growth factor BB (PDGF-BB) in a concentration-dependent manner. At 24 hours irradiated fibroblasts invaded the fibrin gel almost as well as non-irradiated cells, indicating that transmigration was independent of proliferation. Plasminogen and its activators appear to be necessary for invasion of the fibrin clot since protease inhibitors decreased the amount of migration. These serine proteases, however, were not necessary for exit from the collagen gel as fibroblasts migrated out of the collagen gel onto a surface coated with fibrin fibrils even in the presence of inhibitors. Removal of fibronectin (FN) from either the collagen gel or the fibrin gel markedly decreased the number of migrating cells, suggesting that FN provides a conduit for transmigration. Cell movement in the in vitro model was inhibited by RGD peptide, and by monoclonal antibodies against the subunits of the alpha5 beta1 and alpha v beta3 integrin receptor. Thus, the functional requirements for fibroblast transmigration from collagen-rich to fibrin-rich matrices, such as occurs in early wound healing, have been partially defined using an in vitro paradigm of this important biologic process.

  2. Increased axonal regeneration through a biodegradable amnionic tube nerve conduit: effect of local delivery and incorporation of nerve growth factor/hyaluronic acid media.

    Mohammad, J A; Warnke, P H; Pan, Y C; Shenaq, S

    2000-01-01

    The authors emphasize the possible pharmacological enhancement of axonal regeneration using a specific growth factor/ extracellular media incorporated in a biodegradable nonneural nerve conduit material. They investigated the early effects on nerve regeneration of continuous local delivery of nerve growth factor (NGF) and the local incorporation of hyaluronic acid (HA) inside a newly manufactured nerve conduit material from fresh human amnionic membrane. Human amnionic membrane contains important biochemical factors that play a major neurotrophic role in the nerve regeneration process. The process of manufacturing a nerve conduit from fresh human amnionic membrane is described. This nerve conduit system was used in rabbits to bridge a 25-mm nerve gap over 3 months. NGF was released locally, over 28 days, at the distal end of the tube via a system of slow release, and HA was incorporated inside the lumen of the tube at the time of surgery. NGF/HA treatment promoted axonal regeneration across the amnionic tube nerve conduit (8,962 +/- 383 myelinated axons) 45% better than the nontreated amnionic tube group (6,180 +/- 353 myelinated axons). The authors demonstrate that NGF/HA media enhances additional axonal regeneration in the amnionic tube nerve conduit. This result is secondary to the effect of the amnion promoting biochemical factors, in combination with the NGF/HA effect on facilitating early events in the nerve regeneration process.

  3. Soil vapor extraction with dewatering

    Thomson, N.R. [Univ. of Waterloo, Ontario (Canada)

    1996-08-01

    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  4. Tungsten chemical vapor deposition method

    Hirano, Kiichi; Takeda, Nobuo.

    1993-07-13

    A tungsten chemical vapor deposition method is described, comprising: a first step of selectively growing a first thin tungsten film of a predetermined thickness in a desired region on the surface of a silicon substrate by reduction of a WF[sub 6] gas introduced into an atmosphere of a predetermined temperature containing said silicon substrate; and a second step of selectively growing a second tungsten film of a predetermined thickness on said first thin tungsten film by reduction of said WF[sub 6] with a silane gas further introduced into said atmosphere, wherein the surface state of said substrate is monitored by a pyrometer and the switching from said first step to said second step is performed when the emissivity of infrared light from the substrate surfaces reaches a predetermined value.

  5. Blood pressure-independent hypotrophy of the heart, kidneys and conduit arteries after 7-nitroindazole administration to Wistar rats from the prenatal period to adulthood.

    Kristek, F; Malekova, M; Ondrias, K; Cacanyiova, S

    2013-02-01

    The aim of this study was to investigate the long-term effects of 7-nitroindazole on the heart, kidneys, thoracic aorta, and carotid arteries from the progeny of mothers that had been treated with 7-nitroindazole (7NI) (10 mg/kg/day in drinking water) during gestation and nursing. The offspring were also treated with 7NI (10 mg/kg/day in drinking water) until 10 weeks of age. Mean arterial pressure (BP) was measured by tail-cuff plethysmography starting at 4 weeks of age. After perfusion fixation with glutaraldehyde at 120 mmHg, the heart and kidneys were weighed and the thoracic aorta and carotid arteries were processed for morphological investigation. The BP and body weight of treated rats did not differ from age-matched control rats during the course of the experiment. In the experimental group, at the end of the experiment, the heart weight/body weight and kidney weight/body weight ratios were decreased. In addition, the wall thickness (intima + media), cross sectional area (intima + media), and wall thickness/inner diameter ratio were significantly decreased in both the thoracic aorta and carotid arteries without a change in the inner vessel diameter. Circumferential wall tension was increased in both arteries. The data clearly indicate that long-term inhibition of neuronal nitric oxide (NO) synthase with the specific inhibitor 7NI evokes BP-independent hypotrophy of the heart, kidneys, and conduit arterial walls in normotensive Wistar rats.

  6. Can a drawover vaporizer be a pushover?

    Taylor, J C; Restall, J

    1994-10-01

    Bench testing was carried out to establish whether the vapour output from an OMV50 vaporizer, as used in the Triservice apparatus, differs according to whether the carrier gas is either drawn or pushed through the vaporizer. Results show that the differences in output concentration between the two modes were clinically insignificant.

  7. Boron carbide whiskers produced by vapor deposition

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  8. Vapor Pressures of Several Commercially Used Alkanolamines

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    2011-01-01

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N,N-diethylethano

  9. Volcanic risk metrics at Mt Ruapehu, New Zealand: some background to a probabilistic eruption forecasting scheme and a cost/benefit analysis at an open conduit volcano

    Jolly, Gill; Sandri, Laura; Lindsay, Jan; Scott, Brad; Sherburn, Steve; Jolly, Art; Fournier, Nico; Keys, Harry; Marzocchi, Warner

    2010-05-01

    The Bayesian Event Tree for Eruption Forecasting software (BET_EF) is a probabilistic model based on an event tree scheme that was created specifically to compute long- and short-term probabilities of different outcomes (volcanic unrest, magmatic unrest, eruption, vent location and eruption size) at long-time dormant and routinely monitored volcanoes. It is based on the assumption that upward movements of magma in a closed conduit volcano will produce detectable changes in the monitored parameters at the surface. In this perspective, the goal of BET_EF is to compute probabilities by merging information from geology, models, past data and present monitoring measurements, through a Bayesian inferential method. In the present study, we attempt to apply BET_EF to Mt Ruapehu, a very active and well-monitored volcano exhibiting the typical features of open conduit volcanoes. In such conditions, current monitoring at the surface is not necessarily able to detect short term changes at depth that may occur only seconds to minutes before an eruption. This results in so-called "blue sky eruptions" of Mt Ruapehu (for example in September 2007), that are volcanic eruptions apparently not preceded by any presently detectable signal in the current monitoring. A further complication at Mt Ruapehu arises from the well-developed hydrothermal system and the permanent crater lake sitting on top of the magmatic conduit. Both the hydrothermal system and crater lake may act to mask or change monitoring signals (if present) that magma produces deeper in the edifice. Notwithstanding these potential drawbacks, we think that an attempt to apply BET_EF at Ruapehu is worthwhile, for several reasons. First, with the exception of a few "blue sky" events, monitoring data at Mt Ruapehu can be helpful in forecasting major events, especially if a large amount of magma is intruded into the edifice and becomes available for phreatomagmatic or magmatic eruptions, as for example in 1995-96. Secondly, in

  10. Engineering vapor-deposited polyimides

    Tsai, Feng-Yu

    The vapor deposition polymerization (VDP) of PMDA-ODA polyimide was studied parametrically to produce microcapsules and thin films with desirable properties and quality for the Inertial Confinement Fusion (ICF) experiments. The mechanical properties and gas permeability were determined at temperatures from 10 to 573 K. The VDP polyimide possessed distinct properties including lower gas permeability and stronger tensile properties from those of solution-cast Kapton, which were attributed to the presence of cross-linking. Processing parameters determining the properties of the VDP polyimide were identified: (1) utilizing air instead of nitrogen as the atmosphere of imidization increased the permeability by 140%, lowered the activation energy for permeation, and reduced the tensile strength by 30% without affecting the Young's modulus; (2) imidizing at faster heating rates increased the permeability by up to 50% and reduced the activation energy for permeation with 50% lowered tensile strength and impervious Young's modulus; (3) bi-axial stretching increased the permeability by up to three orders of magnitude. Analyses via IR spectroscopy, X-ray diffraction, and density measurement revealed that the effects of the processing parameters were results of the modifications in the crystallinity and molecular weight. The VDP polyimide underwent minor degradation in the tensile strength and elongation at break with unaffected Young's modulus and permeability upon absorbing 120 MGy of beta-radiation. Substituting a fluorinated dianhydride monomer, 6FDA, for PMDA in the optimized VDP process yielded 6FDA-ODA polyimide microcapsules and films with 50-fold increased permeability and comparable mechanical properties. The results of this study enable the production of polyimide microcapsules that will greatly facilitate the ICF experiments, and will broaden the applications of vapor-deposited polyimides in other technology fields.

  11. Microbial growth with vapor-phase substrate

    Hanzel, Joanna; Thullner, Martin; Harms, Hauke [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany); Wick, Lukas Y., E-mail: lukas.wick@ufz.de [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany)

    2011-04-15

    Limited information exists on influences of the diffusive transport of volatile organic contaminants (VOC) on bacterial activity in the unsaturated zone of the terrestrial subsurface. Diffusion of VOC in the vapor-phase is much more efficient than in water and results in effective VOC transport and high bioavailability despite restricted mobility of bacteria in the vadose zone. Since many bacteria tend to accumulate at solid-water, solid-air and air-water interfaces, such phase boundaries are of a special interest for VOC-biodegradation. In an attempt to evaluate microbial activity toward air-borne substrates, this study investigated the spatio-temporal interplay between growth of Pseudomonas putida (NAH7) on vapor-phase naphthalene (NAPH) and its repercussion on vapor-phase NAPH concentrations. Our data demonstrate that growth rates of strain PpG7 were inversely correlated to the distance from the source of vapor-phase NAPH. Despite the high gas phase diffusivity of NAPH, microbial growth was absent at distances above 5 cm from the source when sufficient biomass was located in between. This indicates a high efficiency of suspended bacteria to acquire vapor-phase compounds and influence headspace concentration gradients at the centimeter-scale. It further suggests a crucial role of microorganisms as biofilters for gas-phase VOC emanating from contaminated groundwater or soil. - Research highlights: > Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene. > Bacteria influence NAPH vapor-phase concentration gradients at centimeter-scale. > Microbial growth on vapor-phase naphthalene is inversely correlated to its source. > Bacteria are good biofilters for gas-phase NAPH emanating from contaminated sites. - Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene and effectively influence vapor-phase naphthalene concentration gradients at the centimeter scale.

  12. HANFORD CHEMICAL VAPORS WORKER CONCERNS & EXPOSURE EVALUATION

    ANDERSON, T.J.

    2006-12-20

    Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank headspaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns. risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits-(OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors.

  13. Magmatic Conduit Metallogenic System in Jinchuan Cu-Ni (PGE) Sulfide Deposit

    Su, S.; Tang, Z.; Zhou, M.; Song, C.

    2014-12-01

    The Jinchuan Cu-Ni (PGE) sulfide deposit is located in the southwestern margin of North China Craton. Jinchuan ultramafic intrusion hosts the third largest magmatic Cu-Ni deposit in the world. There are mainly four orebodies, namely, orebody-58, orebody-24, orebody-1, and orebody-2, respectively from west to east in the deposit. The primary characteristics of Jinchuan Cu-Ni sulfide deposit are the following: (1) There is an obvious boundary between orebodys and country rocks, usually orebodys intruded into country rocks. (2) "sulfide melts" migrate and settle in the later stage of magma evolution. (3) Fluid Minerals Assemblages are found in the sulfide ores, there is Phl+Cc+Pn+Ccp+Po in orebody-2; Phl+Dol+AP+Pn+Ccp+Po in orebody-24; Q+Mag+AP+Pn+Ccp+Po in orebody-58. (4) Massive sulfides mainly occur in orebody-2, and its PGE content is very rare. Pt-Pd enrichment zones mainly occur in orebody-1; orebody-24 and orebody-58. Ir vs. Ru, Rh, Pt, Pd show positive relationship in orebody-2, but Ir vs. Ru, Rh show positive relationship, Ir vs. Pt, Pd exhibit negative relationship in orebody-1, orebody-24 and orebody-58. The modeling of Ir-Pd shows that the massive sulfide in orebody-2 maybe the origin of MSS. Pt-Pd enrichment zones in orebody-1 orebody-24 and orebody-58 are the relic liquid of monosulfide solid solution segregation; (5) Cu/Ni value is 1.24 in orebody-58, 1.56 in orebody-24, 1.83 in orebody-1, and 2.06 in orebody-2. These features imply that (1) "ore magma" or "melt-fluid bearing metal" formed in the staging chamber in depth; (2) "ore magma" might contain a lot of fluids; (3) "melt-fluid bearing metal" flow moves as a whole; (4) The moving direction of melt-fluid bearing metal flow is form west to east. The ores are enriched in Ni in the front, and enriched in Cu, Pt, Pd in the back of Jinchuan Magmatic Conduit Metallogenic System.

  14. The QBO as potential amplifier and conduit to lower altitudes of solar cycle influence

    H. G. Mayr

    2007-06-01

    tapping the momentum from the upward propagating gravity waves. Influenced and amplified by wave processes, the QBO thus acts as conduit to transfer to lower altitudes the larger SC variations in the UV absorbed in the mesosphere. Our model produces in the temperature variations of the QBO and EAO measurable SC modulations at polar latitudes near the tropopause. The effects are apparently generated by the meridional circulation, and planetary waves presumably, which redistribute the energy from the equatorial region where the waves are very effective in amplifying the SC influence.

  15. Formation of obsidian pyroclasts by sintering of ash particles in the volcanic conduit

    Gardner, James E.; Llewellin, Edward W.; Watkins, James M.; Befus, Kenneth S.

    2017-02-01

    The ranges in intensity and style of volcanic eruptions, from highly explosive Plinian eruptions to quiescent lava extrusions, depend on the style and efficiency of gas loss from ascending magma. Obsidian pyroclasts - small, glassy pieces of quenched magma found in some volcanic tephra beds - may preserve valuable information about magma degassing in their vesicle textures and volatile contents. Accurate interpretation of their textures and volatiles, however, requires understanding the mechanism of formation of the pyroclasts. Obsidian pyroclasts from the ca. 1325-1350 C.E. North Mono eruption of Mono Craters (CA, USA) were analyzed and found to have H2O and CO2 contents indicating that they were formed at pressures in the approximate range of 3-40 MPa. Many also contain domains with differing vesicle textures, separated by boundaries containing xenocrystic material, indicating that they are composed of smaller fragments that have sutured together. More than half of the pyroclasts analyzed contained small (∼10 μm), highly distorted vesicles, with multi-cuspate morphology, interpreted as the remnants of interstitial gas trapped amongst sintered fragments of melt/glass. Rounded vesicles are also common and are interpreted to result from surface tension-driven relaxation of the distorted vesicles. Calculated timescales of sintering and relaxation are consistent with timescales for pyroclast formation indicated by H2O re-equilibration within the heterogeneous pyroclasts. This sintering model for the origin of obsidian pyroclasts is further supported by the observation that spherical vesicles are found mainly in H2O-rich pyroclasts, and distorted vesicles mainly in H2O-poor pyroclasts. We conclude that obsidian pyroclasts generated during the North Mono eruption were formed by cycles of fragmentation, sintering/suturing, and relaxation, over a very wide range of depths within the conduit; we find no evidence to support pumice (foam) collapse as the formation

  16. Characterization and Schwann Cell Seeding of up to 15.0 cm Long Spider Silk Nerve Conduits for Reconstruction of Peripheral Nerve Defects

    Tim Kornfeld

    2016-11-01

    Full Text Available Nerve reconstruction of extended nerve defect injuries still remains challenging with respect to therapeutic options. The gold standard in nerve surgery is the autologous nerve graft. Due to the limitation of adequate donor nerves, surgical alternatives are needed. Nerve grafts made out of either natural or artificial materials represent this alternative. Several biomaterials are being explored and preclinical and clinical applications are ongoing. Unfortunately, nerve conduits with successful enhancement of axonal regeneration for nerve defects measuring over 4.0 cm are sparse and no conduits are available for nerve defects extending to 10.0 cm. In this study, spider silk nerve conduits seeded with Schwann cells were investigated for in vitro regeneration on defects measuring 4.0 cm, 10.0 cm and 15.0 cm in length. Schwann cells (SCs were isolated, cultured and purified. Cell purity was determined by immunofluorescence. Nerve grafts were constructed out of spider silk from Nephila edulis and decellularized ovine vessels. Finally, spider silk implants were seeded with purified Schwann cells. Cell attachment was observed within the first hour. After 7 and 21 days of culture, immunofluorescence for viability and determination of Schwann cell proliferation and migration throughout the conduits was performed. Analyses revealed that SCs maintained viable (>95% throughout the conduits independent of construct length. SC proliferation on the spider silk was determined from day 7 to day 21 with a proliferation index of 49.42% arithmetically averaged over all conduits. This indicates that spider silk nerve conduits represent a favorable environment for SC attachment, proliferation and distribution over a distance of least 15.0 cm in vitro. Thus spider silk nerve implants are a highly adequate biomaterial for nerve reconstruction.

  17. Characterization and Schwann Cell Seeding of up to 15.0 cm Long Spider Silk Nerve Conduits for Reconstruction of Peripheral Nerve Defects.

    Kornfeld, Tim; Vogt, Peter M; Bucan, Vesna; Peck, Claas-Tido; Reimers, Kerstin; Radtke, Christine

    2016-11-30

    Nerve reconstruction of extended nerve defect injuries still remains challenging with respect to therapeutic options. The gold standard in nerve surgery is the autologous nerve graft. Due to the limitation of adequate donor nerves, surgical alternatives are needed. Nerve grafts made out of either natural or artificial materials represent this alternative. Several biomaterials are being explored and preclinical and clinical applications are ongoing. Unfortunately, nerve conduits with successful enhancement of axonal regeneration for nerve defects measuring over 4.0 cm are sparse and no conduits are available for nerve defects extending to 10.0 cm. In this study, spider silk nerve conduits seeded with Schwann cells were investigated for in vitro regeneration on defects measuring 4.0 cm, 10.0 cm and 15.0 cm in length. Schwann cells (SCs) were isolated, cultured and purified. Cell purity was determined by immunofluorescence. Nerve grafts were constructed out of spider silk from Nephila edulis and decellularized ovine vessels. Finally, spider silk implants were seeded with purified Schwann cells. Cell attachment was observed within the first hour. After 7 and 21 days of culture, immunofluorescence for viability and determination of Schwann cell proliferation and migration throughout the conduits was performed. Analyses revealed that SCs maintained viable (>95%) throughout the conduits independent of construct length. SC proliferation on the spider silk was determined from day 7 to day 21 with a proliferation index of 49.42% arithmetically averaged over all conduits. This indicates that spider silk nerve conduits represent a favorable environment for SC attachment, proliferation and distribution over a distance of least 15.0 cm in vitro. Thus spider silk nerve implants are a highly adequate biomaterial for nerve reconstruction.

  18. Making meaning(s with cover designs

    Yvonne Reed

    2011-08-01

    Full Text Available In this article Halliday’s systemic functional grammar, Kress and Van Leeuwen’s grammar of visual design and Bernstein’s work on pedagogic discourse are drawn on in order to analyze some of the ways in which meanings are made and some meanings privileged over others in the designing, both visual and discursive, of the covers of three course books prepared for teacher education programmes in South Africa. The primary aim of this analysis is to understand what meanings are offered to readers as entrants into or as established members of communities of practice in the teaching profession and the academy.

  19. Characterization of Upper-Troposphere Water Vapor Measurements during AFWEX Using LASE

    Ferrare, Richard; Browell, E. V.; Ismail, S.; Barrick, J. D. W.; Diskin, G. S.; Sachse, G. W.; Kooi, S. A.; Brasseur, L. H.; Brackett, V. G.; Clayton, M. B.; Goldsmith, John E M.; Lesht, B. M.; Podolske, J. R.; Schmidlin, F. J.; Turner, David D.; Whiteman, D. N.; Demoz, B. B.; Tobin, D. C.; Revercomb, Henry E.; Miloshevich, Larry M.; di Girolamo, P.

    2004-12-01

    Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors over the Department of Energy Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in northern Oklahoma. LASE was deployed from the NASA DC-8 aircraft and measured water vapor over the ARM SGP Central Facility (CF) site during seven flights between November 27 and December 10, 2000. Initially, the DOE ARM SGP Cloud and Radiation Testbed (CART) Raman lidar (CARL) UTWV profiles were about 5-7% wetter than LASE in the upper troposphere, and the Vaisala RS80-H radiosonde profiles were about 10% drier than LASE between 8-12 km. Scaling the Vaisala water vapor profiles to match the precipitable water vapor (PWV) measured by the ARM SGP microwave radiometer (MWR) did not change these results significantly. By accounting for an overlap correction of the CARL water vapor profiles and by employing schemes designed to correct the Vaisala RS80-H calibration method and account for the time response of the Vaisala RS80H water vapor sensor, the average differences between the CARL and Vaisala radiosonde upper troposphere water vapor profiles are reduced to about 5%, which is within the ARM goal of mean differences of less than 10%. The LASE and DC-8 in situ Diode Laser Hygrometer (DLH) UTWV measurements generally agreed to within about 3 to 4%. The DC-8 in situ frost point cryogenic hygrometer and Snow White chilled mirror measurements were drier than the LASE, Raman lidars, and corrected Vaisala RS80H measurements by about 10-25% and 10-15%, respectively. Sippican (formerly VIZ manufacturing) carbon hygristor radiosondes exhibited large variabilities and poor agreement with the other measurements. PWV derived from the LASE profiles agreed to within about 3% on average with

  20. Experimental analysis of bubble-driven magma motion in a volcanic conduit and how it affects lava lake sustainability

    Pansino, S. G.; Calder, E. S.; Menand, T.

    2013-12-01

    The effect of bubble ascent dynamics on magma motion within a conduit has not previously been well studied. Investigation of bubble dynamics is undertaken using an analogue model for magma convection in a volcanic conduit, representing the upper-most section where large bubbles or gas slugs can be present. In the experiments, bubbles rise through an initially stagnant medium in a cylindrical tube and the resulting liquid descent velocity (liquid flux) is measured. The effects of gas flux and liquid viscosity on liquid flux are determined. It is shown that liquid flux depends on gas flux and on the two-phase flow regime. The induced liquid flux is an order of magnitude higher when the two-phase flow regime is turbulent rather than laminar. For each flow regime, scaling analysis is used to describe how the liquid flux changes with gas flux (using experimentally-derived data). The liquid flux is roughly 15% of the gas flux in the turbulent regime and 1% of the gas flux in the laminar regime. These models are then applied to field and remote sensing data from selected volcanoes to determine how the magma flux estimation changes with consideration of bubble dynamics. Bubble-driven liquid motions can have a significant effect on magma convection in low-viscosity systems (less than 103 Pa*s), affecting the shallowest hundreds to tens of meters of magma in the conduit. In higher-viscosity magmas, these effects are more suppressed, causing laminar flow proportions of magma flux. Keywords: magma convection, lava lakes, bubble-driven convection, persistent volcanism, gas dynamics, two-phase flow, degassing

  1. Projections of Horizontal Water Vapor Transport across Europe

    Lavers, D. A.

    2015-12-01

    With a warming Earth's atmosphere, the global water cycle is expected to intensify, a process that is likely to yield changes in the frequency and intensity of hydrological extremes. To quantify such changes over Europe, most previous research has been based upon precipitation scenarios. However, seldom has the horizontal water vapor transport (integrated vapor transport IVT) been investigated, a key variable responsible for heavy precipitation events and one that links water source and sink regions. It is hence the aim of this study to assess the projections of IVT across Europe. The Climate Model Intercomparison Project Phase 5 (CMIP5) is the source of the climate model projections. The historical simulations (1979-2005) and two emissions scenarios (2073-2099), or representative concentration pathways (RCP4.5 and RCP8.5) from 22 global circulation models were retrieved and evaluated. In particular, at model grid points across Europe the mean, standard deviation, and the 95th percentile of IVT were calculated for December, January, and February (Boreal winter); and for June, July, and August (Austral winter). The CMIP5 historical multi-model mean closely resembles the ECMWF ERA-Interim reanalysis. In the future under the two emissions scenarios, the IVT increases in magnitude, with the highest percentage changes occurring in the extreme emissions (RCP8.5) scenario; for example, multi-model mean IVT increases of 30% are found in the domain. An evaluation of the low-altitude moisture and winds indicates that higher atmospheric water vapor content is the primary cause of these projected changes.

  2. Prevention of pacemaker-associated contact dermatitis by polytetrafluoroethylene sheet and conduit coating of the pacemaker system.

    Taguchi, Takahiro; Maeba, Satoru; Sueda, Taijiro

    2014-09-01

    A 73-year-old female with sick sinus syndrome and atrial fibrillation was implanted with a ventricular demand inhibit pacemaker. She subsequently developed multiple episodes of skin irritation and necrosis. Skin patch testing revealed sensitivity to almost every component of the pacemaker system. The pacemaker was removed and replaced with a new pacemaker in which the generator was covered with a polytetrafluoroethylene (PTFE) sheet and the lead was covered with PTFE conduit. The patient suffered no further episodes of pacemaker-associated contact dermatitis.

  3. El vapor de ruedas "Cid": de pionero de la navegación comercial a vapor a primer vapor hospital

    O. González García

    Full Text Available La aparición de la máquina de vapor había hecho realidad el sueño de navegar sin depender de las fuerzas de la naturaleza. La carrera por lograr un vapor comercial eficiente había comenzado. Con retraso por la Guerra de la Independencia, España se incorporó a la carrera. Entre los primeros vapores comerciales estaba el vapor "Cid". En 1859, en la Guerra de África, ante la necesidad de una evacuación regular de bajas se designa al "Cid" como buque hospital, fue la primera vez en el mundo que se usó un vapor hospital. El Dr. Nicasio Landa fue el responsable de realizar la misión con una organización moderna, eficaz y ejemplar. Pronto los vapores de ruedas perdieron su batalla con los de hélice y el "Cid" quedó obsoleto. Sin embargo, a pesar de su corta vida operativa, poco más de quince años, escribió una importante página en la historia de la navegación en España.

  4. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion.

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2014-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not widely used due to the perceived effort in setting them up. In this manuscript, we present a new closed-form analytical expression describing subsurface contaminant vapor concentrations, including subslab vapor concentrations. The expression was derived using Schwarz-Christoffel mapping. Results from this analytical model match well the numerical modeling results. This manuscript also explores the relationship between subslab and exterior soil gas vapor concentrations, and offers insights on what parameters need to receive greater focus in field studies.

  5. Global warming without global mean precipitation increase?

    Salzmann, Marc

    2016-06-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K(-1) decrease of the water vapor concentration with cooling from anthropogenic aerosol because the water vapor radiative feedback lowers the hydrological sensitivity to anthropogenic forcings. When GHG and aerosol forcings are combined, the climate models with a realistic 20th century warming indicate that the global mean precipitation increase due to GHG warming has, until recently, been completely masked by aerosol drying. This explains the apparent lack of sensitivity of the global mean precipitation to the net global warming recently found in observations. As the importance of GHG warming increases in the future, a clear signal will emerge.

  6. Control procedures and interface man-machine; Procedures de conduite et interface homme-machine

    Appell, B.; Guesnier, G. [Electricite de France, 75 - Paris (France). Service Etudes et Projets Thermiques et Nucleaires; Chambon, Y. [Ecole Nationale Superieure d`Electrotechnique, d`Electronique, d`Informatique et d`Hydraulique (ENSEEIHT), 31 - Toulouse (France)]|[Electricite de France, 75 - Paris (France). Service Etudes et Projets Thermiques et Nucleaires

    1998-07-01

    The accident of Three Miles Island in United State in 1979 has shown the fundamental part of man in the driving of a nuclear facility. Since this date, numerous studies have been done to find the best organization relative to documents, teams and driving means. The approach consists in ensuring a defense by using the whole of means at disposal. A description of these means is given in details. (N.C.)

  7. Global warming without global mean precipitation increase?

    Salzmann, Marc

    2016-01-01

    Global climate models simulate a robust increase of global mean precipitation of about 1.5 to 2% per kelvin surface warming in response to greenhouse gas (GHG) forcing. Here, it is shown that the sensitivity to aerosol cooling is robust as well, albeit roughly twice as large. This larger sensitivity is consistent with energy budget arguments. At the same time, it is still considerably lower than the 6.5 to 7% K−1 decrease of the water vapor concentration with cooling from anthropogenic aeroso...

  8. Leidenfrost Vapor Layer Stabilization on Superhydrophobic Surfaces

    Vakarelski, Ivan; Patankar, Neelesh; Marston, Jeremy; Chan, Derek; Thoroddsen, Sigurdur

    2012-11-01

    We have performed experiments to investigate the influence of the wettability of a superheated metallic sphere on the stability of a thin vapor layer during the cooling of a sphere immersed in water. For high enough sphere temperatures, a continuous vapor layer (Leidenfrost regime) is observed on the surface of non-superhydrophobic spheres, but below a critical sphere temperature the layer becomes unstable and explosively switches to nuclear boiling regime. In contrast, when the sphere surface is textured and superhydrophobic, the vapor layer is stable and gradually relaxes to the sphere surface until the complete cooling of the sphere, thus avoiding the nuclear boiling transition altogether. This finding could help in the development of heat exchange devices and of vapor layer based drag reducing technologies.

  9. Static Water Vapor Feed Electrolyzer Project

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  10. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  11. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect

    Luo, Lihua [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Center of Molecular Medicine, School of Medicine, Hubei University of Arts and Sciences, Xiangyang 441053 (China); Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China); Wang, Xiong; Huselstein, Celine [Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), UMR 7365 CNRS – Université de Lorraine, Biopôle, 54500 Vandoeuvre-lès-Nancy (France); Chen, Yun, E-mail: yunchen@whu.edu.cn [Department of Biomedical Engineering, School of Basic Medical Sciences, Wuhan University, Wuhan 430071 (China)

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  12. Trends of total water vapor column above the Arctic from satellites observations

    Alraddawi, Dunya; Sarkissian, Alain; Keckhut, Philippe; Bock, Olivier; Claud, Chantal; Irbah, Abdenour

    2016-04-01

    Atmospheric water vapor (H2O) is the most important natural (as opposed to man-made) greenhouse gas, accounting for about two-thirds of the natural greenhouse effect. Despite this importance, its role in climate and its reaction to climate change are still difficult to assess. Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapor. In contrast to other important greenhouse gases like carbon dioxide (CO2) and methane, water vapor has a much higher temporal and spatial variability. Total precipitable water (TPW) or the total column of water vapor (TCWV) is the amount of liquid water that would result if all the water vapor in the atmospheric column of unit area were condensed. TCWV distribution contains valuable information on the vigor of the hydrological processes and moisture transport in the atmosphere. Measurement of TPW can be obtained based on atmospheric water vapor absorption or emission of radiation in the spectral range from UV to MW. TRENDS were found over the terrestrial Arctic by means of TCWV retrievals (using Moderate Resolution Imaging Spectro-radiometer (MODIS) near-infrared (2001-2015) records). More detailed approach was made for comparisons with ground based instruments over Sodankyla - Finland (TCWV from: SCIAMACHY 2003-2011, GOME-2A 2007-2011, SAOZ 2003-2011, GPS 2003-2011, MODIS 2003-2011)

  13. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not w...

  14. Internalized Meaning Factualism

    Hohwy, Jakob

    2006-01-01

    The normative character of meaning creates deep problems for the attempt to give a reductive explanation of the constitution of meaning. I identify and critically examine an increasingly popular Carnap-style position, which I call Internalized Meaning Factualism (versions of which I argue...... that is internal to meaning discourse, then we can preserve the normativity of meaning and yet locate meaning in the natural world. I develop a generic motivation for this position, but argue that, since this motivation is consistent with the Ramsey-Carnap-Lewis-Jackson reductionist strategy, internalized meaning...

  15. Opportunities for Energy Development in Water Conduits: A Report Prepared in Response to Section 7 of the Hydropower Regulatory Efficiency Act of 2013

    Sale, Michael J. [BCS, Incorporated, Laurel, MD (United States); Bishop, Norman A. [Knight Piesold, Chicago, IL (United States); Reiser, Sonya L. [Knight Piesold, Chicago, IL (United States); Johnson, Kurt [Telluride Energy LLC, Grand Junction, CO (United States); Bailey, Andrea C. [BCS, Incorporated, Laurel, MD (United States); Frank, Anthony [BCS, Incorporated, Laurel, MD (United States); Smith, Brennan T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2014-09-01

    In Section 7 of the Hydropower Regulatory Efficiency Act (HREA) of 2013 (P.L. 113-23), Congress directed the U.S. Department of Energy (DOE) to prepare an analysis of conduit hydropower opportunities available in the United States and to present case studies that describe the potential energy generation from these types of hydropower projects. Those analyses have been included in a new DOE report to Congress, and this ORNL/TM provides additional technical details supporting that report. Conduit hydropower offers important new ways to enhance renewable energy portfolios in the United States, as well as to increase the energy efficiency of water delivery systems. Conduit hydropower projects are constructed on existing water-conveyance structures, such as irrigation canals or pressurized pipelines that deliver water to municipalities, industry, or agricultural water users. Although water conveyance infrastructures are usually designed for non-power purposes, new renewable energy can often be harvested from them without affecting their original purpose and without the need to construct new dams or diversions. Conduit hydropower differs from more conventional hydropower development in that it is generally not located on natural rivers or waterways and therefore does not involve the types of environmental impacts that are associated with hydropower. The addition of hydropower to existing water conduits can provide valuable new revenue sources from clean, renewable energy. The new energy can be used within the existing water distribution systems to offset other energy demands, or it can be sold into regional transmission systems.

  16. Three-layer microfibrous peripheral nerve guide conduit composed of elastin-laminin mimetic artificial protein and poly(L-lactic acid)

    Kakinoki, Sachiro; Nakayama, Midori; Moritan, Toshiyuki; Yamaoka, Tetsuji

    2014-07-01

    We developed a microfibrous poly(L-lactic acid) (PLLA) nerve conduit with a three-layered structure to simultaneously enhance nerve regeneration and prevent adhesion of surrounding tissue. The inner layer was composed of PLLA microfiber containing 25% elastin-laminin mimetic protein (AG73-(VPGIG)30) that promotes neurite outgrowth. The thickest middle layer was constructed of pure PLLA microfibers that impart the large mechanical stremgth to the conduit. A 10% poly(ethylene glycol) was added to the outer layer to prevent the adhesion with the surrounding tissue. The AG73-(VPGIG)30 composisting of an elastin-like repetitive sequence (VPGIG)30 and a laminin-derived sequence (RKRLQVQLSIRT: AG73) was biosynthesized using Escherichia coli. The PLLA microfibrous conduits were fabricated using an electrospinning procedure. AG73-(VPGIG)30 was successfully mixed in the PLLA microfibers, and the PLLA/AG73-(VPGIG)30 microfibers were stable under physiological conditions. The PLLA/AG73-(VPGIG)30 microfibers enhanced adhesion and neurite outgrowth of PC12 cells. The electrospun microfibrous conduit with a three-layered structure was implanted for bridging a 2.0-cm gap in the tibial nerve of a rabbit. Two months after implantation, no adhesion of surrounding tissue was observed, and the action potential was slightly improved in the nerve conduit with the PLLA/AG73-(VPGIG)30 inner layer.

  17. Insights into Focused Fluid Conduit Formation from Comparing Seismic Chimneys and Pipes with Field Observations of Fluid Flow Manifestations in the Colorado Plateau

    Karstens, J.; Berndt, C.

    2014-12-01

    The understanding of focused fluid flow in sedimentary basins builds on field geological observations and the interpretation of reflection seismic data, where fluid conduits manifest as anomalous amplitude patterns known as seismic chimneys or pipes. Seismic data is the most effective method for the analysis of entire fluid flow systems by constraining subsurface geometries, fluid accumulations and permeability barriers, but seismic data cannot provide information about the internal architecture, interaction with the bedrock and flow processes due to its coarse resolution. Field geological investigations of fluid conduit outcrops are capable of filling observation gaps on a sub-seismic scale and help constrain formation dynamics as well as hydraulic properties of fluid conduits and the bedrock. Here, we show that it is possible to correlate specific amplitude patterns of seismic chimneys with field observation of focused fluid conduits from the Colorado Plateau. The migrating fluids (gas, water, fluidized sediment) and their formation dynamics, which can be associated with different types of conduits (fractures, fluidizations, injections), result in distinguishable seismic signatures. These constrains improve the qualitative interpretation of seismic chimneys by adding information about migration and formation characteristics. A further integration of field geological and seismic investigation of focused fluid flow structures may help to quantify their hydraulic properties and how these evolve with time, which has important implications for the hydrocarbon prospection and the subsurface storage of wastewater and CO2.

  18. Three-layer microfibrous peripheral nerve guide conduit composed of elastin-laminin mimetic artificial protein and poly(L-lactic acid

    Sachiro eKakinoki

    2014-07-01

    Full Text Available We developed a microfibrous poly(L-lactic acid (PLLA nerve conduit with a three-layered structure to simultaneously enhance nerve regeneration and prevent adhesion of surrounding tissue. The inner layer was composed of PLLA microfiber containing 25% elastin-laminin mimetic protein (AG73-(VPGIG30 that promotes neurite outgrowth. The thickest middle layer was constructed of pure PLLA microfibers that impart the large mechanical stremgth to the conduit. A 10% poly(ethylene glycol was added to the outer layer to prevent the adhesion with the surrounding tissue. The AG73-(VPGIG30 composisting of an elastin-like repetitive sequence (VPGIG30 and a laminin-derived sequence (RKRLQVQLSIRT: AG73 was biosynthesized using Escherichia coli. The PLLA microfibrous conduits were fabricated using an electrospinning procedure. AG73-(VPGIG30 was successfully mixed in the PLLA microfibers, and the PLLA/AG73-(VPGIG30 microfibers were stable under physiological conditions. The PLLA/AG73-(VPGIG30 microfibers enhanced adhesion and neurite outgrowth of PC12 cells. The electrospun microfibrous conduit with a three-layered structure was implanted for bridging a 2.0-cm gap in the tibial nerve of a rabbit. Two months after implantation, no adhesion of surrounding tissue was observed, and the action potential was slightly improved in the nerve conduit with the PLLA/AG73-(VPGIG30 inner layer.

  19. Vapor Pressure of 2-Chlorovinyl Dichloroarsine (Lewisite)

    2009-02-01

    Streams of Compounds for Determining Vapor Pressure 11 3. Vapor Pressure of Lewisite I from Multiple Sources: Conant, Sumner, Lewis, Keyes, Price ...number of publications in the open literature by Green and Price ,4 Lewis and Perkins,5 Mann and Pope, Mohler and Polya7 and Gibson and Johnson.8...point. (2) Banks et al.,14 reported that during the fractional distillation of the reaction products of phenyl dichloroarsine and acetylene , 2

  20. Binary Schemes of Vapor Bubble Growth

    Zudin, Yu. B.

    2015-05-01

    A problem on spherically symmetric growth of a vapor bubble in an infi nite volume of a uniformly superheated liquid is considered. A description of the limiting schemes of bubble growth is presented. A binary inertial-thermal bubble growth scheme characterized by such specifi c features as the "three quarters" growth law and the effect of "pressure blocking" in a vapor phase is considered.

  1. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  2. Vapor Hydrogen Peroxide Sterilization Certification

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  3. Bioeffects due to acoustic droplet vaporization

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  4. Nerve growth factor combined with an epineural conduit for bridging a short nerve gap (10 mm). A study in rabbits.

    Barmpitsioti, Antonia; Konofaos, Petros; Ignatiadis, Ioannis; Papalois, Apostolos; Zoubos, Aristides B; Soucacos, Panagiotis N

    2011-10-01

    The purpose of this study was to evaluate the effect of direct administration of nerve growth factor (NGF) into an epineural conduit across a short nerve gap (10 mm) in a rabbit sciatic nerve model. The animals were divided into two groups. In group 1, n = 6, a 10-mm defect was created in the sciatic nerve and bridged with an epineural flap. A dose of 1 μg of NGF was locally administered daily for the first 21 days. NGF administration was made inside the epineural flap using a silicone reservoir connected to a silicone tube. In group 2, n = 6, the 10-mm defect was bridged with a nerve graft. This group did not receive any further treatment. At 13 weeks, all animals, before euthanasia, underwent electromyography (EMG) studies and then specimen sent for histology morphometric analysis. NGF administration ensured a significantly increased average number of myelinated axons per μm(2) (P = 0.028) and promoted fiber maturation (P = 0.031) and better EMG results (P = 0.046 for latency P = 0.048 for amplitude), compared with the control group. Although nerve grafts remain the gold standard for peripheral nerve repair, NGF-treated epineural conduits represent a good alternative, particularly when an unfavorable environment for nerve grafts is present.

  5. Anatomy of a deep crustal volcanic conduit system; The Reinfjord Ultramafic Complex, Seiland Igneous Province, Northern Norway

    Grant, Thomas B.; Larsen, Rune B.; Anker-Rasch, Lars; Grannes, Kim Rune; Iljina, Markku; McEnroe, Suzanne; Nikolaisen, Even; Schanche, Mona; Øen, Endre

    2016-05-01

    The Reinfjord Ultramafic Complex, Seiland Igneous Province represents a lower crustal magma chamber (25-30 km depth) that likely records a deep conduit system for mantle derived melts ascending through the continental crust. It consists of cumulates of dunite, wehrlite, olivine clinopyroxene as well as subordinate lherzolite and websterites, intruded into gabbro-norite and metasediment gneisses. Field, petrographic and geochemical data show that the intrusion developed through fractional crystallization and interactions between new batches of magma and partially solidified cumulates. This resulted in a 'reverse fractionation sequence' whereby cumulates became progressively more MgO and olivine rich with time. Contamination by partial melting of the gabbro-norite is evident in the marginal zones, but is limited in the central parts of the intrusion. Interrupted crystallization sequences of olivine → olivine + clinopyroxene and the absence of significant amounts of more evolved melts, suggests that large volumes of melt passed through the system to shallower levels in the crust leaving behind the cumulate sequences observed at Reinfjord. Therefore, the Reinfjord Ultramafic Complex represents a deep crustal conduit system, through which mantle derived melts passed. The parent melts are likely to have formed from partial melting of mantle with residual garnet and clinopyroxene.

  6. 33 CFR 154.808 - Vapor control system, general.

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor control system, general... (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.808 Vapor control system, general. (a) A vapor control system design and installation must...

  7. The effect of shear on permeability in a volcanic conduit: a case study at Unzen volcano, Japan

    Ashworth, James; Lavallée, Yan; Wallace, Paul; Lamur, Anthony; Kendrick, Jackie; Miwa, Takahiro

    2016-04-01

    The efficiency of outgassing at volcanoes is a function of permeability, and exerts a major influence on the type of eruptive behaviour exhibited. Understanding how shear affects the permeability profile across volcanic conduits is therefore a key part of understanding volcanic processes and the associated hazards. During the final months of the 1990-1995 eruption of Unzen volcano in southern Japan, extrusion of a dacite spine followed a period of endogenous dome growth. Many of the resulting formations are relatively accessible, allowing for the study of a variety of associated deformation phenomena. One of these formations, a ~6 m wide block, is a section of the extruded spine, that forms the basis for this study on shallow conduit processes. It displays a textural gradation from highly sheared rock to rock with negligible deformation, and is bounded at the high shear end by an agglutinated block of gouge that is thought to represent the conduit margin. A multi-faceted approach was taken to investigate the variation of permeability across the spine and its implications for processes occurring within the conduit. The permeability was measured at several points along the exposed surface of the spine transect using a field permeameter. Sample blocks from four of these locations were collected and tested in the lab using a hydrostatic pressure vessel water-flow permeameter and categorized as: gouge; highest shear; moderate shear; negligible shear. Each block was tested in three orthogonal axes: one perpendicular to observed shear; and two in the plane of shear. For each of these rocks, permeability and porosity measurements were made at a wide range of effective pressures (5 to 100 MPa), using a controlled upstream/downstream pore pressure gradient of 0.5 MPa (at an average pore pressure of 1.25 MPa). Thin sections of each sample were also taken prepared and analysed to describe the primary microstructures controlling the permeability of the rock. Textural analysis

  8. Relationship between vapor intrusion and human exposure to trichloroethylene.

    Archer, Natalie P; Bradford, Carrie M; Villanacci, John F; Crain, Neil E; Corsi, Richard L; Chambers, David M; Burk, Tonia; Blount, Benjamin C

    2015-01-01

    Trichloroethylene (TCE) in groundwater has the potential to volatilize through soil into indoor air where it can be inhaled. The purpose of this study was to determine whether individuals living above TCE-contaminated groundwater are exposed to TCE through vapor intrusion. We examined associations between TCE concentrations in various environmental media and TCE concentrations in residents. For this assessment, indoor air, outdoor air, soil gas, and tap water samples were collected in and around 36 randomly selected homes; blood samples were collected from 63 residents of these homes. Additionally, a completed exposure survey was collected from each participant. Environmental and blood samples were analyzed for TCE. Mixed model multiple linear regression analyses were performed to determine associations between TCE in residents' blood and TCE in indoor air, outdoor air, and soil gas. Blood TCE concentrations were above the limit of quantitation (LOQ; ≥ 0.012 µg L(-1)) in 17.5% of the blood samples. Of the 36 homes, 54.3%, 47.2%, and >84% had detectable concentrations of TCE in indoor air, outdoor air, and soil gas, respectively. Both indoor air and soil gas concentrations were statistically significantly positively associated with participants' blood concentrations (P = 0.0002 and P = 0.04, respectively). Geometric mean blood concentrations of residents from homes with indoor air concentrations of >1.6 µg m(-3) were approximately 50 times higher than geometric mean blood TCE concentrations in participants from homes with no detectable TCE in indoor air (P < .0001; 95% CI 10.4-236.4). This study confirms the occurrence of vapor intrusion and demonstrates the magnitude of exposure from vapor intrusion of TCE in a residential setting.

  9. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; Lee, Xuhui; Xiao, Ke; Chen, Zichong; Welp, Lisa R.; Schultz, Natalie M.; Gorski, Galen; Chen, Ming; Nieber, John

    2016-04-01

    Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle - an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from -40.2 to -15.9 ‰ and δ2Hv ranged from -278.7 to -113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol-1) indicate that regional evaporation can account

  10. Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

    Feng Xue; Er-jun Wu; Pei-xun Zhang; Li-ya A; Yu-hui Kou; Xiao-feng Yin; Na Han

    2015-01-01

    We examined the restorative effect of modiifed biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantationin vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial ifbrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve ifbers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our ifndings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi-ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  11. 21 CFR 1040.30 - High-intensity mercury vapor discharge lamps.

    2010-04-01

    ... mercury and that is contained within an outer envelope. (2) Advertisement means any catalog, specification... ballast is an inductive reactor designed to have the operating characteristics as listed in Section 7 in... advertisement. Advertising for any high-intensity mercury vapor discharge lamp that does not comply...

  12. Initiated-chemical vapor deposition of organosilicon layers: Monomer adsorption, bulk growth, and process window definition

    Aresta, G.; Palmans, J.; M. C. M. van de Sanden,; Creatore, M.

    2012-01-01

    Organosilicon layers have been deposited from 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (V3D3) by means of the initiated-chemical vapor deposition (i-CVD) technique in a deposition setup, ad hoc designed for the engineering of multilayer moisture permeation barriers. The application of Fourier

  13. Phoenix Water Vapor Measurements using the SSI Camera

    Tamppari, Leslie; Lemmon, Mark T.

    2016-10-01

    The Phoenix and Mars Reconnaissance Orbiter (MRO) spacecraft participated together in an observation campaign that was a coordinated effort to study the Martian atmosphere. These coordinated observations were designed to provide near-simultaneous observations of the same column of atmosphere over the Phoenix lander. Seasonal coverage was obtained at Ls=5-10° resolution and diurnal coverage was obtained as often as possible and with as many times of day as possible. One key aspect of this observation set was the means to compare the amount of water measured in the whole column (via the MRO Compact Reconnaissance Imaging Spectrometer for Mars (CRISM; Murchie et al., 2007) and the Phoenix Surface Stereo Imager (SSI) with that measured at the surface (via the Phoenix Thermal and Electrical Conductivity probe (TECP; Zent et al., 2008) which contained a humidity sensor). This comparison, along with the Phoenix LIDAR observations of the depth to which aerosols are mixed (Whiteway et al., 2008, 2009), provides clues to the water vapor mixing ratio profile. Tamppari et al. (2009) showed that examination of a subset of these coordinated observations indicate that the water vapor is not well mixed in the atmosphere up to a cloud condensation height at the Phoenix location during northern summer, and results indicated that a large amount of water must be confined to the lowest 0.5-1 km. This is contrary to the typical assumption that water vapor is "well-mixed."Following a similar approach to Titov et al. (2000), we use the Phoenix SSI camera [Lemmon et al., 2008] filters to detect water vapor: LA = 930.7 nm (broad), R4 = 935.5 nm (narrow), and R5 = 935.7 nm (narrow). We developed a hybrid DISORT-spherical model (DISORT model, Stamnes et al. 1988) to model the expected absorption due to a prescribed water vapor content and profile, to search for matches to the observations. Improvements to the model have been made and recent analysis using this model and comparisons to

  14. Means on scattered compacta

    Banakh T.

    2014-01-01

    Full Text Available We prove that a separable Hausdor_ topological space X containing a cocountable subset homeomorphic to [0, ω1] admits no separately continuous mean operation and no diagonally continuous n-mean for n ≥ 2.

  15. Utilization of the second gradient theory in continuum mechanics to study motions and thermodynamics of liquid-vapor interfaces

    Gouin, Henri

    2011-01-01

    A thermomechanical model of continuous fluid media based on second gradient theory is used to study motions in liquid-vapor interfaces. At equilibrium, the model is shown to be equivalent to mean-field molecular theories of capillarity. In such fluids, conservative motions verify first integrals that lead to Kelvin circulation theorems and potential equations. The dynamical surface tension of liquid-vapor interfaces is deduced from viscous fluid equations. The result provides and explains the Marangoni effect.

  16. Molecular dynamics of the water liquid-vapor interface

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1987-01-01

    The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

  17. Construction of nerve guide conduits from cellulose/soy protein composite membranes combined with Schwann cells and pyrroloquinoline quinone for the repair of peripheral nerve defect.

    Luo, Lihua; Gan, Li; Liu, Yongming; Tian, Weiqun; Tong, Zan; Wang, Xiong; Huselstein, Celine; Chen, Yun

    2015-02-20

    Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide

  18. Conduit dynamics in transitional rhyolitic activity recorded by tuffisite vein textures from the 2008-2009 Chaitén eruption

    Elodie eSaubin

    2016-05-01

    Full Text Available The mechanisms of hazardous silicic eruptions are controlled by complex, poorly-understood conduit processes. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent. Such behaviour hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. Intersection of foam domains by tuffisite veins appears critical to efficient outgassing. However, knowledge is currently lacking into textural heterogeneities within shallow conduits, their relationship with tuffisite vein propagation, and the implications for fragmentation and degassing processes. Similarly, the magmatic vesiculation response to upper conduit pressure perturbations, such as those related to the slip of dense magma plugs, remains largely undefined. Here we provide a detailed characterization of an exceptionally large tuffisite vein within a rhyolitic obsidian bomb ejected during transitional explosive-effusive activity at Chaitén, Chile in May 2008. Vein textures and chemistry provide a time-integrated record of the invasion of a dense upper conduit plug by deeper fragmented magma. Quantitative textural analysis reveals diverse vesiculation histories of various juvenile clast types.Using vesicle size distributions, bubble number densities, zones of diffusive water depletion, and glass H2O concentrations, we propose a multi-step degassing/fragmentation history, spanning deep degassing to explosive bomb ejection. Rapid decompression events of ~3-4 MPa are associated with fragmentation of foam and dense magma at ~200-350 metres depth in the conduit, permitting vertical gas and pyroclast mobility over hundreds of metres. Permeable pathway occlusion in the dense conduit plug by pyroclast accumulation

  19. Conduit dynamics in transitional rhyolitic activity recorded by tuffisite vein textures from the 2008-2009 Chaitén eruption

    Saubin, Elodie; Tuffen, Hugh; Gurioli, Lucia; Owen, Jacqueline; Castro, Jonathan; Berlo, Kim; McGowan, Ellen; Schipper, C. Ian; Wehbe, Katia

    2016-04-01

    Conduit processes govern the mechanisms of hazardous silicic eruptions, but our understanding of complex conduit behaviour is far from complete. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent[1]. Such behaviour hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. However, we have limited insights into the interactions between tuffisites and foams that appear critical to efficient outgassing[2], and into how heterogeneous conduit magma responds to pressure perturbations related to repeated disruption or slip of dense magma plugs. Here we provide a detailed characterization of an exceptionally large tuffisite vein within a rhyolitic obsidian bomb ejected during transitional explosive-effusive activity at volcán Chaitén, Chile in May 2008. Vein textures and chemistry provide a time-integrated record of the invasion of a dense upper conduit plug by deeper fragmented magma. Quantitative textural analysis reveals diverse vesiculation histories of varied juvenile clast types. Using vesicle size distributions, bubble number densities, zones of diffusive water depletion, and glass H2O concentrations, we propose a multi-step degassing/fragmentation history, spanning deep degassing to explosive bomb ejection. Rapid decompression events of ~3-4 MPa are associated with fragmentation of foam and dense magma at ~200-300 metres depth in the conduit, permitting vertical gas and pyroclast mobility over >100-200 metres. Permeable pathway occlusion in the dense conduit plug by pyroclast accumulation and sintering preceded ultimate bomb ejection, which triggered a final bubble nucleation event. Our results highlight how the vesiculation response of magma to decompression

  20. Conduit dynamics in transitional rhyolitic activity recorded by tuffisite vein textures from the 2008-2009 Chaitén eruption

    Saubin, Elodie; Tuffen, Hugh; Gurioli, Lucia; Owen, Jacqueline; Castro, Jonathan; Berlo, Kim; McGowan, Ellen; Schipper, C.; Wehbe, Katia

    2016-05-01

    The mechanisms of hazardous silicic eruptions are controlled by complex, poorly-understood conduit processes. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent. Such behaviour hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. Intersection of foam domains by tuffisite veins appears critical to efficient outgassing. However, knowledge is currently lacking into textural heterogeneities within shallow conduits, their relationship with tuffisite vein propagation, and the implications for fragmentation and degassing processes. Similarly, the magmatic vesiculation response to upper conduit pressure perturbations, such as those related to the slip of dense magma plugs, remains largely undefined. Here we provide a detailed characterization of an exceptionally large tuffisite vein within a rhyolitic obsidian bomb ejected during transitional explosive-effusive activity at Chaitén, Chile in May 2008. Vein textures and chemistry provide a time-integrated record of the invasion of a dense upper conduit plug by deeper fragmented magma. Quantitative textural analysis reveals diverse vesiculation histories of various juvenile clast types. Using vesicle size distributions, bubble number densities, zones of diffusive water depletion, and glass H2O concentrations, we propose a multi-step degassing/fragmentation history, spanning deep degassing to explosive bomb ejection. Rapid decompression events of ~3-4 MPa are associated with fragmentation of foam and dense magma at ~200-350 metres depth in the conduit, permitting vertical gas and pyroclast mobility over hundreds of metres. Permeable pathway occlusion in the dense conduit plug by pyroclast accumulation and sintering

  1. Agency, Context and Meaning

    Folkmann, Mads Nygaard

    2014-01-01

    history, 2) the question of context in and of design, i.e. which contexts give meaning to design; this question calls for interpretive models of cultural analysis of the circuit of design in acknowledging phases and aspects of production, mediation and consumption, and 3) the question of the meaning...... of meaning formulation and cultural contexts and, by this, contest design. In reflecting the foundational ground of design in terms of its agency, contexts and meaning constituents, design and its questioning of meaning can be critically reframed....

  2. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion.

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2013-10-01

    Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The "open field" soil gas vapor concentration profile is observed to be sensitive to the soil moisture distribution. The van Genuchten relations can be used for describing the soil moisture retention curve, and give results consistent with the results from a previous experimental study. Other modeling methods that account for soil moisture are evaluated. These modeling results are also compared with the measured subsurface concentration profiles in the U.S. EPA vapor intrusion database.

  3. Vapor scavenging by atmospheric aerosol particles

    Andrews, E.

    1996-05-01

    Particle growth due to vapor scavenging was studied using both experimental and computational techniques. Vapor scavenging by particles is an important physical process in the atmosphere because it can result in changes to particle properties (e.g., size, shape, composition, and activity) and, thus, influence atmospheric phenomena in which particles play a role, such as cloud formation and long range transport. The influence of organic vapor on the evolution of a particle mass size distribution was investigated using a modified version of MAEROS (a multicomponent aerosol dynamics code). The modeling study attempted to identify the sources of organic aerosol observed by Novakov and Penner (1993) in a field study in Puerto Rico. Experimentally, vapor scavenging and particle growth were investigated using two techniques. The influence of the presence of organic vapor on the particle`s hydroscopicity was investigated using an electrodynamic balance. The charge on a particle was investigated theoretically and experimentally. A prototype apparatus--the refractive index thermal diffusion chamber (RITDC)--was developed to study multiple particles in the same environment at the same time.

  4. Thermodynamics and Kinetics of Silicate Vaporization

    Jacobson, Nathan S.; Costa, Gustavo C. C.

    2015-01-01

    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  5. Explosive vapor detection payload for small robots

    Stimac, Phil J.; Pettit, Michael; Wetzel, John P.; Haas, John W.

    2013-05-01

    Detection of explosive hazards is a critical component of enabling and improving operational mobility and protection of US Forces. The Autonomous Mine Detection System (AMDS) developed by the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) is addressing this challenge for dismounted soldiers. Under the AMDS program, ARA has developed a vapor sampling system that enhances the detection of explosive residues using commercial-off-the-shelf (COTS) sensors. The Explosives Hazard Trace Detection (EHTD) payload is designed for plug-and-play installation and operation on small robotic platforms, addressing critical Army needs for more safely detecting concealed or exposed explosives in areas such as culverts, walls and vehicles. In this paper, we describe the development, robotic integration and performance of the explosive vapor sampling system, which consists of a sampling "head," a vapor transport tube and an extendable "boom." The sampling head and transport tube are integrated with the boom, allowing samples to be collected from targeted surfaces up to 7-ft away from the robotic platform. During sample collection, an IR lamp in the sampling head is used to heat a suspected object/surface and the vapors are drawn through the heated vapor transport tube to an ion mobility spectrometer (IMS) for detection. The EHTD payload is capable of quickly (less than 30 seconds) detecting explosives such as TNT, PETN, and RDX at nanogram levels on common surfaces (brick, concrete, wood, glass, etc.).

  6. The evolution of periodic seismicity, waveform similarity, and conduit processes during unrest episodes at Tungurahua volcano, Ecuador, in 2015

    Bell, Andrew; Hernandez, Stephen; Gaunt, Elizabeth; Mothes, Patricia; Hidalgo, Silvana; Ruiz, Mario

    2016-04-01

    Tungurahua is a large andesitic stratovolcano located in the Andes of Ecuador. The current eruptive phase at Tungurahua began in 1999, and has been characterised by episodes of vulcanian and strombolian activity, interspersed by periods of relative quiescence. Despite showing only modest eruptive activity in 2015, seismic data revealed a pronounced change in the behaviour of the magma-conduit system compared to the preceding 15 years of activity. The change is most notable in the periodicity of interevent-times of volcanic earthquakes. Previous seismicity at Tungurahua is characterised by interevent-time periodicities typical of a Poisson process, or modestly clustered, with slightly elevated (anti-clustered) periodicities observed only rarely during vulcanian episodes. However, activity in 2015 saw a series of unrest episodes characterised by highly-periodic interevent-times, and including several notable episodes of 'drumbeat' earthquakes. Here we report seismic and associated geophysical signals recorded at Tungurahua in 2015 by the monitoring network of the Instituto Geofisico of Ecuador, their relation to conduit processes, and implications for the origins of unrest and likely future activity. Although the nature of the low-frequency seismic signals change both within and between unrest episodes, the underlying periodicity is more consistent and gradually evolving. Waveform similarity is high within phases, resulting from the repeated activation of persistent sources, but low between different episodes, suggesting the emergence of new sources and locations. The strength of periodicity is correlated with the average waveform similarity for all unrest episodes, with the relatively low waveform similarities observed for the highly periodic drumbeat earthquakes in April due to contamination from coexisting continuous tremor. Eruptive activity consisted of a few minor explosions and ash emission events. Notably, a short-lived episode of Strombolian activity in

  7. A Numerical Investigation of Vapor Intrusion — the Dynamic Response of Contaminant Vapors to Rainfall Events

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    The U.S. government and various agencies have published guidelines for field investigation of vapor intrusion, most of which suggest soil gas sampling as an integral part of the investigation. Contaminant soil gas data are often relatively more stable than indoor air vapor concentration measurements, but meteorological conditions might influence soil gas values. Although a few field and numerical studies have considered some temporal effects on soil gas vapor transport, a full explanation of the contaminant vapor concentration response to rainfall events is not available. This manuscript seeks to demonstrate the effects on soil vapor transport during and after different rainfall events, by applying a coupled numerical model of fluid flow and vapor transport. Both a single rainfall event and seasonal rainfall events were modeled. For the single rainfall event models, the vapor response process could be divided into three steps: namely, infiltration, water redistribution, and establishment of a water lens atop the groundwater source. In the infiltration step, rainfall intensity was found to determine the speed of the wetting front and wash-out effect on the vapor. The passage of the wetting front led to an increase of the vapor concentration in both the infiltration and water redistribution steps and this effect is noted at soil probes located 1 m below the ground surface. When the mixing of groundwater with infiltrated water was not allowed, a clean water lens accumulated above the groundwater source and led to a capping effect which can reduce diffusion rates of contaminant from the source. Seasonal rainfall with short time intervals involved superposition of the individual rainfall events. This modeling results indicated that for relatively deeper soil that the infiltration wetting front could not flood, the effects were damped out in less than a month after rain; while in the long term (years), possible formation of a water lens played a larger role in

  8. A numerical investigation of vapor intrusion--the dynamic response of contaminant vapors to rainfall events.

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2012-10-15

    The U.S. government and various agencies have published guidelines for field investigation of vapor intrusion, most of which suggest soil gas sampling as an integral part of the investigation. Contaminant soil gas data are often relatively more stable than indoor air vapor concentration measurements, but meteorological conditions might influence soil gas values. Although a few field and numerical studies have considered some temporal effects on soil gas vapor transport, a full explanation of the contaminant vapor concentration response to rainfall events is not available. This manuscript seeks to demonstrate the effects on soil vapor transport during and after different rainfall events, by applying a coupled numerical model of fluid flow and vapor transport. Both a single rainfall event and seasonal rainfall events were modeled. For the single rainfall event models, the vapor response process could be divided into three steps: namely, infiltration, water redistribution, and establishment of a water lens atop the groundwater source. In the infiltration step, rainfall intensity was found to determine the speed of the wetting front and wash-out effect on the vapor. The passage of the wetting front led to an increase of the vapor concentration in both the infiltration and water redistribution steps and this effect is noted at soil probes located 1m below the ground surface. When the mixing of groundwater with infiltrated water was not allowed, a clean water lens accumulated above the groundwater source and led to a capping effect which can reduce diffusion rates of contaminant from the source. Seasonal rainfall with short time intervals involved superposition of the individual rainfall events. This modeling results indicated that for relatively deeper soil that the infiltration wetting front could not flood, the effects were damped out in less than a month after rain; while in the long term (years), possible formation of a water lens played a larger role in determining

  9. Water vapor release from biofuel combustion

    Parmar, R. S.; Welling, M.; Andreae, M. O.; Helas, G.

    2008-03-01

    We report on the emission of water vapor from biofuel combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are compared to carbon in the biofuel. Fuel types included hardwood (oak and African musasa), softwood (pine and spruce, partly with green needles), and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the emissions from 16 combustion experiments ranged from 1.2 to 3.7 on average, indicating the presence of water that is not chemically bound. This biofuel moisture content ranged from 33% in the dry African hardwood, musasa, to 220% in fresh pine branches with needles. The moisture content from fresh biofuel contributes distinctly to the water vapor in biomass burning emissions, and its influence on meteorology needs to be evaluated.

  10. Water vapor release from biomass combustion

    Parmar, R. S.; Welling, M.; Andreae, M. O.; Helas, G.

    2008-10-01

    We report on the emission of water vapor from biomass combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are referenced to carbon in the biomass. The investigated fuel types include hardwood (oak and African musasa), softwood (pine and spruce, partly with green needles), and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the emissions from 16 combustion experiments ranged from 1.2 to 3.7, indicating the presence of water that is not chemically bound. This non-bound biomass moisture content ranged from 33% in the dry African hardwood, musasa, to 220% in fresh pine branches with needles. The moisture content from fresh biomass contributes significantly to the water vapor in biomass burning emissions, and its influence on the behavior of fire plumes and pyro-cumulus clouds needs to be evaluated.

  11. Water vapor release from biofuel combustion

    R. S. Parmar

    2008-03-01

    Full Text Available We report on the emission of water vapor from biofuel combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are compared to carbon in the biofuel. Fuel types included hardwood (oak and African musasa, softwood (pine and spruce, partly with green needles, and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the emissions from 16 combustion experiments ranged from 1.2 to 3.7 on average, indicating the presence of water that is not chemically bound. This biofuel moisture content ranged from 33% in the dry African hardwood, musasa, to 220% in fresh pine branches with needles. The moisture content from fresh biofuel contributes distinctly to the water vapor in biomass burning emissions, and its influence on meteorology needs to be evaluated.

  12. Possible seasonal variability of mesospheric water vapor

    Bevilacqua, R. M.; Schwartz, P. R.; Wilson, W. J.; Ricketts, W. B.; Howard, R. J.

    1985-01-01

    Ground-based spectral line measurements of the 22.2 GHz water vapor line in atmospheric emission were made at the Jet Propulsion Laboratory, which have been used to deduce the mesospheric water vapor profile. The measurements were made nearly continuously in the spring and early summer of 1984. The results indicate a temporal increase in the water vapor mixing ratio in the upper mesosphere from April through June. At 75 km, this increase is nearly by a factor of 2. Comparison of the present results with the results of a similar series of measurements made at the Haystack (radio astronomy) Observatory indicate that this temporal increase is part of a seasonal variation.

  13. Toxicity evaluation of chicken calamus keratin conduit as a tissueengineering scaffold biomaterial%鸡羽根角蛋白管毒性作用的研究

    董为人; 赵冰雷; 肖应庆; 仇欣霞; 陈英华; 邹仲之

    2007-01-01

    Objective To evaluate the toxicity of chicken calamus keratin (CCK) conduit as a tissue-engineered scaffold material. Methods The chemical composition of the leaching solution of CCK was determined by means of ultraviolet spectrometry, and the toxic effects of the solution was evaluated by skin sensitization test in rats, intracutaneous stimulation test in rabbits, acute systemic toxicity test in mice, and cytotoxicity test in L929 cells. Results The leaching solution of CCK consisted mainly of middle-molecular-weight peptides with a small quantity of macromolecular proteins. Skin sensitization test in rats showed that application of the CCK leaching solution caused no obvious skin reddening, regional edema, or skin necrosis. Intracutaneous injection of the leaching solution in rabbits did not induce obvious skin stimulation manifested by intradermal erythema or edema. In acute systemic toxic test, administration of the leaching solution in mice caused no death,organ dysfunction, cyanosis, tremor, severe peritoneal irritation, ptosis, or dyspnoea. In ivtro cytotoxicity test indicated that the cell toxicity of the CCK leaching solution was approximately at 0 level. Conclusion CCK contained in the treated chicken calamus easily undergoes hydrolysis to release mainly some peptides which do not induce obvious toxic effects, suggesting the safe potential applications of CCK conduit as a tissue-engineering biometerial.%目的 观察鸡羽根角蛋白管作为组织工程材料的毒性作用.方法 分别制备不同处理强度的3种鸡羽根角蛋白管的浸提液并测定其化学成分.采用皮肤致敏实验(大鼠)、皮内刺激实验(家兔)、小鼠全身急性毒性实验以及体外细胞毒性实验观察鸡羽根角蛋白管浸提液的体内和体外毒性作用.结果 鸡羽根在浸出液中释放的主要物质为中等分子量的肽类物质,大分子蛋白释放不多.皮肤致敏实验和皮内刺激实验显示对浸提液不引起皮肤及皮

  14. Reconstrução arterial com tubo de pericárdio bovino corrugado Arterial reconstruction with crimped bovine pericardial conduit

    Cláudio A Salles

    1992-06-01

    /or abdominal aorta, including aneurysms, acute dissections, coarctation and aorto-iliac lesion. The thoracic aortic reconstruction was performed in 25 patients, including aortic valve replacement in 10, the abdominal aorta in 2, and the aortic bifurcation in 2. Three patients (Group II with complex congenital heart lesions underwent reconstruction of the right ventricular outflow tract in 2, and the Fontan operation in 1. Hospital mortality in Group I was 24% (7 patients. Causes of death were low cardiac output in 4, recurrence of aortic dissection in 2 and respiratory infection in 1. Six of them had been operated upon as emergencies due to acute aortic dissection. All patients in group II survived the operation. There was 1 late death in group I due to methabolic complications related to diabetes and chronic renal failure. This initial clinical experience showed a mean follow-up of 16 months per patient and the longest follow-up was 32 months. It was not observed any late complication related to the crimped bovine pericardial conduit up-to-date.

  15. Short-term spasmodic switching of volcanic tremor source activation in a conduit of the 2011 Kirishima eruption

    Matsumoto, S.; Shimizu, H.; Matsushima, T.; Uehira, K.; Yamashita, Y.; Nakamoto, M.; Miyazaki, M.; Chikura, H.

    2012-04-01

    Volcanic tremors are seismic indicators providing clues for magma behavior, which is related to volcanic eruptions and activity. Detection of spatial and temporal variations of volcanic tremors is important for understanding the mechanism of volcanic eruptions. However, temporal variations of tremor activity in short-term than a minute have not been previously detected by seismological observations around volcanoes. Here, we show that volcanic tremor sources were activated at the top of the conduit (i.e. the crater) and at its lower end by analyzing seismograms from a dense seismic array during the 2011 Kirishima eruption. We observed spasmodic switching in the seismic ray direction during a volcanic tremor sequence. Such fine volcanic tremor structure suggests an interaction between tremor sources located in both deep and shallow depths. Our result suggests that seismic array observations can monitor the magma behavior and contribute to the evaluation of the activity's transition.

  16. Gelatin-methacrylamide gel loaded with microspheres to deliver GDNF in bilayer collagen conduit promoting sciatic nerve growth

    Zhuang H

    2016-04-01

    Full Text Available Hai Zhuang,1–3 Shoushan Bu,1 Lei Hua,1 Mohammad A Darabi,2,3 Xiaojian Cao,4 Malcolm Xing2,3 1Department of Stomatology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu Province, People’s Republic of China; 2Department of Mechanical Engineering, Biochemistry & Medical Genetics, 3Children’s Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada; 4Department of Orthopedics, The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu Province, People’s Republic of China Abstract: In this study, we fabricated glial cell-line derived neurotrophic factor (GDNF-loaded microspheres, then seeded the microspheres in gelatin-methacrylamide hydrogel, which was finally integrated with the commercial bilayer collagen membrane (Bio-Gide®. The novel composite of nerve conduit was employed to bridge a 10 mm long sciatic nerve defect in a rat. GDNF-loaded gelatin microspheres had a smooth surface with an average diameter of 3.9±1.8 µm. Scanning electron microscopy showed that microspheres were uniformly distributed in both the GelMA gel and the layered structure. Using enzyme-linked immunosorbent assay, in vitro release studies (pH 7.4 of GDNF from microspheres exhibited an initial burst release during the first 3 days (18.0%±1.3%, and then, a prolonged-release profile extended to 32 days. However, in an acidic condition (pH 2.5, the initial release percentage of GDNF was up to 91.2%±0.9% within 4 hours and the cumulative release percentage of GDNF was 99.2%±0.2% at 48 hours. Then the composite conduct was implanted in a 10 mm critical defect gap of sciatic nerve in a rat. We found that the nerve was regenerated in both conduit and autograft (AG groups. A combination of electrophysiological assessment and histomorphometry analysis of regenerated nerves showed that axonal regeneration and functional recovery in collagen tube filled with GDNF-loaded microspheres

  17. Effect of injecting brain cell growth peptide into conduit at the anastomose end of autogenous vein graft conduit on functional rehabilitation of facial nerve injury%自体静脉套吻合端套管内注入脑细胞生长肽对面神经损伤功能恢复的作用

    韩思源; 宋涛; 王玉新

    2004-01-01

    nerve injury.DESIGN: A case-control study based on diagnosis.SETTING and PARTICIPANTS: Forty-four facial nerve injury patients admitted into the first affiliated hospital of China Medical University from January 1999 to December 2001 and 30 facial nerve injury patients admitted before January 1999 were selected.INTERVENTIONS: Forty-four facial nerve injury patients caused by trauma broken end anastomoses under surgical microscope. Autogenous vein conduit was capped into anastomose and moreover, BCGP was injected into the conend anastomose rehabilitation. The functional recovery of facial expression muscle over time after surgery and the dynamic changes in electromyography(EMG) were observed.MAIN OUTCOME MEASURES: The rehabilitation time of facial expression muscle function was observed and the dynamic changes of conduction velocity of facial nerve were assayed.RESULTS: In 30 traumatic facial nerve injury patients, the fastest function recovery was at 9 weeks and the latest was at 13 weeks with a mean of(11.1 ± 1.1) weeks, which had significance compared with that(25.8 ±1.8) weeks of traditional method ( t = 34. 875, P < 0. 01 ) . In 14 tumor remoral with immediate restoration of facial nerve patients, the fastest function recovery was at 13 weeks and the latest was at 15 weeks with a mean of(13.8 t0. 8) weeks, which had significance in the comparison with that(34. 8 ±2.9) weeks of traditional method( t =26. 336, P < 0. 001) . There was an increasing tendency in conduction velocity(CV) of facial nerve in the test of EMG, and there was no significant difference of CV between two methods when the function of facial expression muscle recovered ( P > 0. 05).CONCLUSION: There is more significant effectiveness of the method of injecting brain cell growth peptide into conduit at the anastomose end of autogenous vein graft conduit compared with traditional method, which is a restoration method in facial nerve injury with more outstanding clinical effectiveness.

  18. The Activity and Enthalpy of Vaporization of Nicotine from Tobacco at Moderate Temperatures

    St.Charles F. Kelley

    2016-01-01

    Full Text Available The vapor pressure of nicotine has been reported for unprotonated nicotine and for nicotine-water solutions. Yet no published values exist for nicotine in any commercially relevant matrix or for protonated forms (e.g., tobacco, smoke, electronic cigarette solutions, nicotine replacement products, nicotine salts. Therefore a methodology was developed to measure nicotine activity (defined as the vapor pressure from a matrix divided by the vapor pressure of pure nicotine. The headspace concentration of nicotine was measured for pure nicotine and tobacco stored at 23, 30, and 40 °C which allowed for conversion to vapor pressure and nicotine activity and for the estimation of enthalpy of vaporization. Burley, Flue-cured, Oriental, and cigarette blends were tested. Experiments were conducted with pure nicotine initially until the storage and sampling techniques were validated by comparison with previously published values. We found that the nicotine activity from tobacco was less than 1% with Burley > Flue-cured > Oriental. At 23 °C the nicotine vapor pressure averaged by tobacco type was 0.45 mPa for Oriental tobacco, 1.8 mPa for Flue-cured, 13 mPa for Burley while pure nicotine was 2.95 Pa. In general, the nicotine activity increased as the (calculated unprotonated nicotine concentration increased. The nicotine enthalpy of vaporization from tobacco ranged from 77 kJ/mol to 92 kJ/mol with no obvious trends with regard to tobacco origin, type, stalk position or even the wide range of nicotine activity. The mean value for all tobacco types was 86.7 kJ/mol with a relative standard deviation of 6.5% indicating that this was an intrinsic property of the nicotine form in tobacco rather than the specific tobacco properties. This value was about 30 kJ/mol greater than that of pure nicotine and is similar to the energy needed to remove a proton from monoprotonated nicotine.

  19. High temperature thermodynamics and vaporization of the zirconium--niobium--oxygen system

    Rinehart, G.H.

    1978-05-18

    The vaporization behavior of the Zr--Nb--O system was studied by means of successive vaporization, Knudsen effusion-target collection experiments, and mass spectrometric analysis of the vapors effusing from a Knudsen crucible. The successive vaporization experiments were performed on two ternary samples in open crucibles. X-ray powder diffraction patterns of the residues and x-ray fluorescence analysis of the condensates and residues indicated the preferential vaporization of niobium-containing species with the composition of the residue subsequently becoming closer to that of congruently vaporizing ZrO/sub 2-x/. The Knudsen effusion-target collection experiments were employed on two samples, pure NbO/sub 2/(s) and a two-phase ZrO/sub 2/--NbO/sub 2/ mixture, in order to obtain information on the activity of NbO/sub 2/ in the two-phase mixture. Second law enthalpies and entropies of sublimation as well as third law enthalpies were obtained for both systems. The vaporization behaviors of five compositions in the Zr--Nb--O system, NbO/sub 2/, NbO, a ZrO/sub 2/--NbO/sub 2/ two-phase mixture, Nb/sub 2/O/sub 5/, and Zr/sub 6/Nb/sub 2/O/sub 17/, were investigated. Above Nb/sub 2/O/sub 5/ and the fully oxidized Zr/sub 6/Nb/sub 2/O/sub 17/ oxygen is preferentially lost; over NbO/sub 2/, the two-phase ZrO/sub 2/--NbO/sub 2/ system, and NbO the principal gaseous species is NbO/sub 2/.

  20. Vapor-Particle Separation Using Microporous Metallic Membrane in Crossflow Filtration

    Cheng, Mengdawn [ORNL

    2013-01-01

    Simultaneous separation of vapor and particles in industrial processes could be a key step toward manufacturing of high-quality goods. The separation is critical for successful measurement of volatile or semi-volatile aerosol particles, which no reliable technique exists. We have developed a technique for separation of vapor and particles simultaneously using a specialty microporous metallic membrane. The separator allows the thermally denuded particles traverse straight through the membrane tube, while the vapor molecules permeate through the membrane, separate from the particles and are removed subsequently. The separation technique virtually eliminates the possibility of contamination by vapor re- condensation. We tested the prototype of the vapor-particle separator (VPS) using aerosols prepared from sodium chloride to represent non-volatile aerosols. Chemical like dioctyl phthalate was chosen to represent volatile particles. The test aerosol particles were generated by an atomizer followed by a tandem differential mobility analyser to produce a stream of monodisperse particles in the size range of 10 to 100 nm. In real world particles, we tested the VPS using diesel engine particles that is a mixture of complex chemical composition. Number concentration of the nonvolatile particles reduced as the temperature increased, but the mode diameter of the aerosol population remained unchanged. Number concentration of the volatile particles was also reduced as the temperature increased, but their mode diameters became smaller as particles shrunk in diameter. Differences in the thermal behaviour of the particles were attributed to its transition energy barrier and evaporation rate. Mass balance analysis suggests the separation of vapor and test particles was reasonably complete. Thus, we conclude the VPS could provide an effective means for quantitative characterization of aerosol volatility and separation of vapors from particles.

  1. Drag Reduction by Leidenfrost Vapor Layers

    Vakarelski, Ivan Uriev

    2011-05-23

    We demonstrate and quantify a highly effective drag reduction technique that exploits the Leidenfrost effect to create a continuous and robust lubricating vapor layer on the surface of a heated solid sphere moving in a liquid. Using high-speed video, we show that such vapor layers can reduce the hydrodynamic drag by over 85%. These results appear to approach the ultimate limit of drag reduction possible by different methods based on gas-layer lubrication and can stimulate the development of related energy saving technologies.

  2. Drag Reduction by Leidenfrost Vapor Layers

    Vakarelski, Ivan U.; Marston, Jeremy O.; Chan, Derek Y. C.; Thoroddsen, Sigurdur T.

    2011-05-01

    We demonstrate and quantify a highly effective drag reduction technique that exploits the Leidenfrost effect to create a continuous and robust lubricating vapor layer on the surface of a heated solid sphere moving in a liquid. Using high-speed video, we show that such vapor layers can reduce the hydrodynamic drag by over 85%. These results appear to approach the ultimate limit of drag reduction possible by different methods based on gas-layer lubrication and can stimulate the development of related energy saving technologies.

  3. Water vapor release from biomass combustion

    Parmar, R. S.; Welling, M.; Andreae, M. O.; G. Helas

    2008-01-01

    We report on the emission of water vapor from biomass combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are referenced to carbon in the biomass. The investigated fuel types include hardwood (oak and African musasa), softwood (pine and spruce, partly with green needles), and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the ...

  4. Water vapor release from biofuel combustion

    Parmar, R. S.; Welling, M.; Andreae, M. O.; G. Helas

    2008-01-01

    We report on the emission of water vapor from biofuel combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are compared to carbon in the biofuel. Fuel types included hardwood (oak and African musasa), softwood (pine and spruce, partly with green needles), and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the emissions from 16 ...

  5. Guidance on Soil Vapor Extraction Optimization

    2001-06-01

    343 Table LNAPL DNAPL Source: after USEPA 1991 draw\\$vehandbk3.cdr aee p1 4/5/01 M~ssive Clay ) . ’C. ~AA_··’’’· --V,V~ . >:’ .’ ’·Sand...for removing orgamc contaminants with a vapor pressure greater than 0.5 mm mercury (Hg) at 200 Celsius (C). This includes common chlorinated solvents...liquids ( DNAPLs ), solvent vapors, or dissolved contaminants. • Depth to groundwater, seasonal variations, recharge and discharge information including

  6. Regeneration of the nerves in the aerial cavity with an artificial nerve conduit --reconstruction of chorda tympani nerve gaps-.

    Toshiaki Yamanaka

    Full Text Available Due to its anatomical features, the chorda tympani nerve (CTN is sometimes sacrificed during middle ear surgery, resulting in taste dysfunction. We examined the effect of placing an artificial nerve conduit, a polyglycolic acid (PGA-collagen tube, across the gap in the section of the resected chorda tympani nerve (CTN running through the tympanic cavity.The CTN was reconstructed with a PGA-collagen tube in three patients with taste disturbance who underwent CTN resection. To evaluate the effect of the reconstruction procedure on the patients' gustatory function, we measured the patients' electrogustometry (EGM thresholds. The patients were followed-up for at least two years.Gustatory function was completely restored in all of the patients after the reconstruction. The patients' EGM thresholds exhibited early improvements within one to two weeks and had returned to their normal ranges within three months. They subsequently remained stable throughout the two-year follow-up period. In a patient who underwent a second surgical procedure, it was found that the PGA-collagen tube used in the first surgical procedure had been absorbed and replaced by new CTN fibers with blood vessels on their surfaces.These results suggest that reconstruction of the CTN with an artificial nerve conduit, a PGA-collagen tube, allows functional and morphological regeneration of the nerve and facilitates the recovery of taste function. PGA-collagen tubes might be useful for repairing CTNs that are resected during middle ear surgery. Further research is required to confirm these preliminary results although this is the first report to describe the successful regeneration of a nerve running through an aerial space.

  7. Design and synthesis of elastin-like polypeptides for an ideal nerve conduit in peripheral nerve regeneration

    Hsueh, Yu-Sheng [Institute of Biomedical Engineering, College of Engineering, National Taiwan University, Taipei 100, Taiwan (China); Institute of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Savitha, S. [Institute of Biomedical Engineering, College of Engineering, National Taiwan University, Taipei 100, Taiwan (China); Department of Biotechnology, Sree Sastha Institute of Engineering and Technology, Chennai (India); Institute of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Sadhasivam, S. [Division of Biomedical Engineering and Nanomedicine Research, National Health Research Institutes, Miaoli 350, Taiwan (China); Lin, Feng-Huei, E-mail: double@ntu.edu.tw [Institute of Biomedical Engineering, College of Engineering, National Taiwan University, Taipei 100, Taiwan (China); Division of Biomedical Engineering and Nanomedicine Research, National Health Research Institutes, Miaoli 350, Taiwan (China); Institute of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China); Shieh, Ming-Jium [Institute of Biomedical Engineering, College of Engineering, National Taiwan University, Taipei 100, Taiwan (China); College of Medicine, National Taiwan University Hospital, Taipei 100, Taiwan (China); Institute of Biomedical Engineering, College of Medicine, National Taiwan University, Taipei 100, Taiwan (China)

    2014-05-01

    The study involves design and synthesis of three different elastin like polypeptide (ELP) gene monomers namely ELP1, ELP2 and ELP3 that encode for ELP proteins. The formed ELPs were assessed as an ideal nerve conduit for peripheral nerve regeneration. ELP1 was constructed with a small elongated pentapeptide carrying VPGVG sequence to mimic the natural polypeptide ELP. The ELP2 was designed by the incorporation of 4-penta peptide chains to improve the biocompatibility and mechanical strength. Thus, the third position in unique VPGVG was replaced with alanine to VPAVG and in a similar way modified to VPGKG, VPGEG and VPGIG with the substitution of lysine, glutamic acid and isoleucine. In ELP3, fibronectin C5 domain endowed with REDV sequence was introduced to improve the cell attachment. The ELP1, ELP2 and ELP3 proteins expressed by Escherichia coli were purified by inverse transition cycling (ITC). The purified ELPs were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. The Schwann cell (SC) morphology and cell adhesion were assessed by fabrication of ELP membrane cross-linked with glutaraledhyde. The Schwann cell proliferation was measured by WST-1 assay. Immunofluorostaining of Schwann cells was accomplished with SC specific phenotypic marker, S100. - Highlights: • Design and synthesis of three gene monomers of elastin like polypeptides (ELP1, 2 and 3) were reported. • Molecular weight of ITC purified ELP1, ELP2 and ELP3 was in the range of 37–38 kDa. • Schwann cell adhesion was found to be prominent in ELP3 and could be used as nerve conduit for peripheral nerve regeneration.

  8. Parallel k-means++

    2017-04-04

    A parallelization of the k-means++ seed selection algorithm on three distinct hardware platforms: GPU, multicore CPU, and multithreaded architecture. K-means++ was developed by David Arthur and Sergei Vassilvitskii in 2007 as an extension of the k-means data clustering technique. These algorithms allow people to cluster multidimensional data, by attempting to minimize the mean distance of data points within a cluster. K-means++ improved upon traditional k-means by using a more intelligent approach to selecting the initial seeds for the clustering process. While k-means++ has become a popular alternative to traditional k-means clustering, little work has been done to parallelize this technique. We have developed original C++ code for parallelizing the algorithm on three unique hardware architectures: GPU using NVidia's CUDA/Thrust framework, multicore CPU using OpenMP, and the Cray XMT multithreaded architecture. By parallelizing the process for these platforms, we are able to perform k-means++ clustering much more quickly than it could be done before.

  9. The textural record of conduit and syn-eruptive degassing preserved in ballistic bombs from cyclic Vulcanian explosions of Galeras volcano, Colombia

    Bain, A. A.

    2015-12-01

    Volcanic bombs preserve textural data that record conduit conditions as well as syn-eruptive processes that acted upon a parcel of magma following decompression. Specifically, these pyroclasts may record several episodes of crystal and bubble growth, as well as bubble coalescence and collapse. Furthermore, bombs retrieved from sequential eruptions provide valuable insight into the unobservable evolution of a volcanic conduit over time. We present results from a morphological and textural study of vesicle size distributions in ballistic bombs from six Vulcanian eruptions from the 2004-2012 period of activity of Galeras volcano, Colombia. These violent eruptions cyclically destroyed and ejected a stalled, degassed and crystal-rich plug and a limited amount of underlying magma. They were followed by resumption of the slow rise of magma in the shallow conduit, accompanied by redevelopment of a plug and the perpetuation of a hazardous cycle. We find that bombs from these eruptions fall into three morphological classes including dense bombs, breadcrusted bombs and vesicular bombs based on the existence or absence of a primary quenched rind and comparison of the interior and exterior vesicularities. We study vesicle populations using image analysis of SEM images followed by stereological conversion to reconstruct the degassing history of each pyroclast. The results of this study will be used to produce a quantitative model of the evolution of porosity, permeability and degassing in the upper conduit of Galeras volcano during the 2004-2012 eruptive episode.

  10. PDLLA/PRGD/β-TCP conduits build the neurotrophin-rich microenvironment suppressing the oxidative stress and promoting the sciatic nerve regeneration.

    Qiu, Tong; Yin, Yixia; Li, Binbin; Xie, Lijuan; Yan, Qiongjiao; Dai, Honglian; Wang, Xinyu; Li, Shipu

    2014-10-01

    A novel nerve guidance conduit comprising poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} (PRGD), poly (d,l-lactic acid) (PDLLA) and β-tricalcium phosphate (β-TCP) was constructed to facilitate the peripheral nerve regeneration. From the comparative study, PDLLA/PRGD/β-TCP conduit achieved the best recovery in regard of the ultrastructure observation and the SFI evaluation. At the first stage of the injury (7 days), the maximum expression augments in ZnSOD (6.4 folds) and GPX4 (6.8 folds) were observed in PDLLA/PRGD/β-TCP group; while striking rise in actin (6.8 folds), tubulin (5.6 folds), and ERM components expressions were observed later (35 days). Meanwhile, compared with PDLLA and PDLLA/PRGD conduits, PDLLA/PRGD/β-TCP conduits achieved the highest local nerve growth factor (NGF) content and an accumulating BDNF content. We speculated that addition of RGD and β-TCP in the composites were the main positive factors to build the microenvironment rich in NGF and BDNF, which help to counteract with the oxidative stress and to boost the cytoskeletal protein expressions. Therefore, PDLLA/PRGD/β-TCP could be promising composites used in peripheral nerve regeneration.

  11. Aerodynamic improvement of the assembly through which gas conduits are taken into a smoke stack by simulating gas flow on a computer

    Prokhorov, V. B.; Fomenko, M. V.; Grigor'ev, I. V.

    2012-06-01

    Results from computer simulation of gas flow motion for gas conduits taken on one and two sides into the gas-removal shaft of a smoke stack with a constant cross section carried out using the SolidWorks and FlowVision application software packages are presented.

  12. Modeling of the vapor cycle of Laguna Verde with the PEPSE code to conditions of thermal power licensed at present (2027 MWt); Modelado del ciclo de vapor de Laguna Verde con el codigo PEPSE a condiciones de potencia termica actualmente licenciada (2027 MWt)

    Castaneda G, M. A.; Maya G, F.; Medel C, J. E.; Cardenas J, J. B.; Cruz B, H. J.; Mercado V, J. J., E-mail: miguel.castaneda01@cfe.gob.mx [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Carretera Cardel-Nautla Km 42.5, Veracruz (Mexico)

    2011-11-15

    By means of the use of the performance evaluation of power system efficiencies (PEPSE) code was modeled the vapor cycle of the nuclear power station of Laguna Verde to reproduce the nuclear plant behavior to conditions of thermal power, licensed at present (2027 MWt); with the purpose of having a base line before the implementation of the project of extended power increase. The model of the gauged vapor cycle to reproduce the nuclear plant conditions makes use of the PEPSE model, design case of the vapor cycle of nuclear power station of Laguna Verde, which has as main components of the model the great equipment of the vapor cycle of Laguna Verde. The design case model makes use of information about the design requirements of each equipment for theoretically calculating the electric power of exit, besides thermodynamic conditions of the vapor cycle in different points. Starting from the design model and making use of data of the vapor cycle measured in the nuclear plant; the adjustment factors were calculated for the different equipment s of the vapor cycle, to reproduce with the PEPSE model the real vapor cycle of Laguna Verde. Once characterized the model of the vapor cycle of Laguna Verde, we can realize different sensibility studies to determine the effects macros to the vapor cycle by the variation of certain key parameters. (Author)

  13. A laser extinction based sensor for simultaneous droplet size and vapor measurement

    Xueqiang Sun; David J. Ewing; Lin Ma

    2012-01-01

    Multiphase flows involving liquid droplets in association with gas flow occur in many industrial and scientific applications.Recent work has demonstrated the feasibility of using optical techniques based on laser extinction to simultaneously measure vapor concentration and temperature and droplet size and loading.This work introduces the theoretical background for the optimal design of such laser extinction techniques,termed WMLE (wavelength-multiplexed laser extinction).This paper focuses on the development of WMLE and presents a systematic methodology to guide the selection of suitable wavelengths and optimize the performance of WMLE for specific applications.WMLE utilizing wavelengths from 0.5to 10 μm is illustrated for droplet size and vapor concentration measurements in an example of water spray,and is found to enable unique and sensitive Sauter mean diameter measurement in the range of ~1-15μm along with accurate vapor detection.A vapor detection strategy based on differential absorption is developed to extend accurate measurement to a significantly wider range of droplet loading and vapor concentration as compared to strategies based on direct fixed-wavelength absorption.Expected performance of the sensor is modeled for an evaporating spray.This work is expected to lay the groundwork for implementing optical sensors based on WMLE in a variety of research and industrial applications involving multi-phase flows.

  14. Estimation of heat load in waste tanks using average vapor space temperatures

    Crowe, R.D.; Kummerer, M.; Postma, A.K.

    1993-12-01

    This report describes a method for estimating the total heat load in a high-level waste tank with passive ventilation. This method relates the total heat load in the tank to the vapor space temperature and the depth of waste in the tank. Q{sub total} = C{sub f} (T{sub vapor space {minus}} T{sub air}) where: C{sub f} = Conversion factor = (R{sub o}k{sub soil}{sup *}area)/(z{sub tank} {minus} z{sub surface}); R{sub o} = Ratio of total heat load to heat out the top of the tank (function of waste height); Area = cross sectional area of the tank; k{sub soil} = thermal conductivity of soil; (z{sub tank} {minus} z{sub surface}) = effective depth of soil covering the top of tank; and (T{sub vapor space} {minus} T{sub air}) = mean temperature difference between vapor space and the ambient air at the surface. Three terms -- depth, area and ratio -- can be developed from geometrical considerations. The temperature difference is measured for each individual tank. The remaining term, the thermal conductivity, is estimated from the time-dependent component of the temperature signals coming from the periodic oscillations in the vapor space temperatures. Finally, using this equation, the total heat load for each of the ferrocyanide Watch List tanks is estimated. This provides a consistent way to rank ferrocyanide tanks according to heat load.

  15. What does the Unexpected Detection of Water Vapor in Arcturus' Atmosphere Tell us?

    Ryde, N; Richter, M J; Lacy, J H; Greathouse, T K; Ryde, Nils; Lambert, David L.; Richter, Matthew J.; Lacy, John H.; Greathouse, Thomas K.

    2002-01-01

    In this talk I presented and discussed our unexpected detection of water vapor in the disk-averaged spectrum of the K2IIIp red giant Arcturus [for details, see Ryde et al. (2002)]. Arcturus, or alpha Bootes is, with its effective temperature of 4300 K, the hottest star yet to show water vapor features. We argue that the water vapor is photospheric and that its detection provides us with new insights into the outer parts of the photosphere. We are not able to model the vater vapor with a standard, one-component, 1D, radiative-equilibrium, LTE model photosphere, which probably means we are lacking essential physics in such models. However, we are able to model several OH lines of different excitation and the water-vapor lines satisfactorily after lowering the temperature structure of the very outer parts of the photosphere at log tau_500=-3.8 and beyond compared to a flux-constant, hydrostatic, standard marcs model photosphere. Our new semi-empirical model is consistently calculated from the given temperature s...

  16. Processing Film, Processing Meaning

    Perkowski, Lisa M.

    2015-01-01

    Adolescents are at a ripe age to make meaning and think abstractly (Kerlavage, 1998); yet, they are not "born knowing how to get ideas into materials, or how materials can be manipulated to shape ideas and meaning" (Burton, 2012, p. 14). Adolescents need guidance in understanding abstract concepts, and art teachers play an important role…

  17. Emprego de condutos de pericárdio bovino na conexão ventrículo-arterial pulmonar: resultados tardios Late results with the use of a valved conduit ot bovine pericardium for ventricle to pulmonary artery connection

    Fernando Antônio Fantini

    1996-09-01

    diseases with an inadequate or absent ventricle to pulmonary artery connection sometimes requires the use of extracardiac conduits. In order to study the longterm outcome of a glutaraldehyde-preserved bovine pericardial conduit valved with a stentless porcine aortic valve, we reviewed the data of 33 patients operated between November 1985 and October 1995. Patients ages ranged from 15 days to 18 years (mean 5.7 ± 4.3 years. Pulmonary atresia with ventricular septal defect (VSD was the most frequent disease (16 cases, followed by tetralogy of Fallot with absent pulmonary valve (5, truncus arteriosus (4, transposition of great arteries with VSD and pulmonary stenosis (3 and other miscellaneous (5. The overall hospital mortality was 18.2% and was related to the preoperative clinical condition; 23 patients (70% were followed by a mean of 4.8 ± 3.0 years (ranging from 3 months to 10 years. The most common late complication observed was stenosis of the anastomosis between the conduit and the pulmonary artery present in 17.4% (4/23 of the patients and was the cause of 2 later reoperations (p=0,02; another patient was reoperated for late conduit endocarditis. This complication was also the cause of 1 of the 4 late deaths (17.4%. The last patient is waiting for surgery. The development of the anastomotic stenosis was problably due to a retraction of the pericardial tissue along the transition with the thin wall of the pulmonary artery. Up to 10 years, gross calcification impairing the function of the valve or the conduit itself could not be detected. In conclusion, the bovine pericardial conduits have shown a good performance as a vascular substitute. Calcification has not been a major drawback. The righ incidence of distal stenosis appears to be more related to a shrinking of the pericardial tissue than to technical reasons.

  18. Mixed convection film condensation from downward flowing vapors onto a sphere with variable wall temperature

    Hsu, C.-H.; Yang, S.-A.

    A model is developed for the study of mixed- convection film condensation from downward flowing vapors onto a sphere with variable wall temperature. The model combined natural convection dominated and forced convection dominated film condensation, concerning effects of pressure gradient (P), interfacial vapor shear drag and non-uniform wall temperature variation (A), has been investigated and solved numerically. The effect of pressure gradient on the dimensionless mean heat transfer, NuRe-1/2 will remain almost uniform with increasing P until P={2 / 9} F for various corresponding available values of F. Meanwhile, the dimensionless mean heat transfer, NuRe-1/2 is increasing significantly with F for its corresponding available values of P. Although the non-uniform wall temperature variation has an appreciable influence on the local film flow and heat transfer; however, the dependence of mean heat transfer on A can be almost negligible.

  19. Water Vapor and the Dynamics of Climate Changes

    Schneider, Tapio; O'Gorman, Paul A.; Levine, Xavier J.

    2010-07-01

    Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus climate. Here we present an overview of how latent heat release affects atmosphere dynamics in a broad range of climates, ranging from extremely cold to extremely warm. Contrary to widely held beliefs, atmospheric circulation statistics can change nonmonotonically with global-mean surface temperature, in part because of dynamic effects of water vapor. For example, the strengths of the tropical Hadley circulation and of zonally asymmetric tropical circulations, as well as the kinetic energy of extratropical baroclinic eddies, can be lower than they presently are both in much warmer climates and in much colder climates. We discuss how latent heat release is implicated in such circulation changes, particularly through its effect on the atmospheric static stability, and we illustrate the circulation changes through simulations with an idealized general circulation model. This allows us to explore a continuum of climates, to constrain macroscopic laws governing this climatic continuum, and to place past and possible future climate changes in a broader context.

  20. Microbial growth with vapor-phase substrate

    Hanzel, J.; Thullner, M.; Harms, H.; Wick, L.Y.

    2011-01-01

    Limited information exists on influences of the diffusive transport of volatile organic contaminants (VOC) on bacterial activity in the unsaturated zone of the terrestrial subsurface. Diffusion of VOC in the vapor-phase is much more efficient than in water and results in effective VOC transport and

  1. Vaporization of atherosclerotic plaques by spark erosion

    C.J. Slager (Cornelis); C.E. Essed; J.C.H. Schuurbiers (Johan); N. Bom (Klaas); P.W.J.C. Serruys (Patrick); G.T. Meester (Geert)

    1985-01-01

    textabstractAn alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and docu

  2. Chemical vapor deposition of mullite coatings

    Sarin, Vinod; Mulpuri, Rao

    1998-01-01

    This invention is directed to the creation of crystalline mullite coatings having uniform microstructure by chemical vapor deposition (CVD). The process comprises the steps of establishing a flow of reactants which will yield mullite in a CVD reactor, and depositing a crystalline coating from the reactant flow. The process will yield crystalline coatings which are dense and of uniform thickness.

  3. Thermodynamics of incongruently vaporizing tungsten diselenide

    Schiffman, R.A.; Franzen, H.F.; Ziegler, R.J.

    1982-03-01

    The incongruent vaporization of WSe/sub 2/ was investigated by a simultaneous weight-loss-mass-spectrometric Knudsen effusion technique in the temperature range 1290-1720 K. For the reaction (1/2)WSe/sub 2/(s) ..-->.. (1/2)W(s) + Se(g), ..delta..H/sub 298//sup 0/ = 311 +/- 3 kJ/mol.

  4. Atomic lithium vapor laser isotope separation

    Olivares, I E

    2002-01-01

    An atomic vapor laser isotope separation in lithium was performed using tunable diode lasers. The method permits also the separation of the isotopes between the sup 6 LiD sub 2 and the sup 7 LiD sub 1 lines using a self-made mass separator which includes a magnetic sector and an ion beam designed for lithium. (Author)

  5. Vaporization of synthetic fuels. Final report. [Thesis

    Sirignano, W.A.; Yao, S.C.; Tong, A.Y.; Talley, D.

    1983-01-01

    The problem of transient droplet vaporization in a hot convective environment is examined. The main objective of the present study is to develop an algorithm for the droplet vaporization which is simple enough to be feasibly incorporated into a complete spray combustion analysis and yet will also account for the important physics such as liquid-phase internal circulation, unsteady droplet heating and axisymmetric gas-phase convection. A simplified liquid-phase model has been obtained based on the assumption of the existence of a Hill's spherical vortex inside the droplet together with some approximations made in the governing diffusion equation. The use of the simplified model in a spray situation has also been examined. It has been found that droplet heating and vaporization are essentially unsteady and droplet temperature is nonuniform for a significant portion of its lifetime. It has also been found that the droplet vaporization characteristic can be quite sensitive to the particular liquid-phase and gas-phase models. The results of the various models are compared with the existing experimental data. Due to large scattering in the experimental measurements, particularly the droplet diameter, no definite conclusion can be drawn based on the experimental data. Finally, certain research problems which are related to the present study are suggested for future studies.

  6. Numerical study of groundwater flow cycling controlled by seawater/freshwater interaction in a coastal karst aquifer through conduit network using CFPv2

    Xu, Zexuan; Hu, Bill X.; Davis, Hal; Kish, Stephen

    2015-11-01

    In this study, a groundwater flow cycling in a karst springshed and an interaction between two springs, Spring Creek Springs and Wakulla Springs, through a subground conduit network are numerically simulated using CFPv2, the latest research version of MODFLOW-CFP (Conduit Flow Process). The Spring Creek Springs and Wakulla Springs, located in a marine estuary and 11 miles inland, respectively, are two major groundwater discharge spots in the Woodville Karst Plain (WKP), North Florida, USA. A three-phase conceptual model of groundwater flow cycling between the two springs and surface water recharge from a major surface creek (Lost Creek) was proposed in various rainfall conditions. A high permeable subground karst conduit network connecting the two springs was found by tracer tests and cave diving. Flow rate of discharge, salinity, sea level and tide height at Spring Creek Springs could significantly affect groundwater discharge and water stage at Wakulla Springs simultaneously. Based on the conceptual model, a numerical hybrid discrete-continuum groundwater flow model is developed using CFPv2 and calibrated by field measurements. Non-laminar flows in conduits and flow exchange between conduits and porous medium are implemented in the hybrid coupling numerical model. Time-variable salinity and equivalent freshwater head boundary conditions at the submarine spring as well as changing recharges have significant impacts on seawater/freshwater interaction and springs' discharges. The developed numerical model is used to simulate the dynamic hydrological process and quantitatively represent the three-phase conceptual model from June 2007 to June 2010. Simulated results of two springs' discharges match reasonably well to measurements with correlation coefficients 0.891 and 0.866 at Spring Creeks Springs and Wakulla Springs, respectively. The impacts of sea level rise on regional groundwater flow field and relationship between the inland springs and submarine springs are

  7. Sexual Function after Non-Nerve-Sparing Radical Cystoprostatectomy: A Comparison between Ileal Conduit Urinary Diversion and Orthotopic Ileal Neobladder Substitution

    M.A Asgari

    2013-07-01

    Full Text Available Objective To compare the erectile function (EF and sexual desire (SD in men after radical cystoprostatectomy (RCP who had either an ileal conduit urinary diversion or orthotropic ileal neobladder substitution. Materials and Methods Eighty one sexually active men with bladder cancer were enrolled in this prospective study. After RCP according to patients' preferences they underwent either ileal conduit urinary diversion (n = 41 or orthotropic ileal neobladder substitution (n = 40. EF and SD were assessed using International Index of Erectile Function (IIEF questionnaire. Patients were assessed at 4-week before surgery and were followed up at 1, 6, and 12-month postoperatively using the same questionnaire. Results Postoperatively the EF and SD domains deteriorated significantly in both groups, but in a small proportion of the patients submitted to ileal neobladder they gradually improved with time (P = 0.006. At 12-month postoperative period, 4 (9.8% and 14 (35.0% patients in ileal conduit and ileal neobladder groups were able to achieve erections hard enough for vaginal penetration and maintained their erection to completion of intercourse, respectively (P = 0.006. Among patients in the ileal conduit and ileal neobladder groups, additional 4 (9.8% and 7 (17.1% patients were able to get some erection, but were unable to maintain their erection to completion of intercourse (P = 0.02. At 12-month follow up period 24.4% of the ileal conduit and 45.0% of the ileal neobladder patients rated their sexual desire very high or high (P = 0.01. Conclusion When performed properly, orthotopic ileal neobladder substitution after RCP offers better long-term results in terms of EF and SD.

  8. Promotion of peripheral nerve regeneration and prevention of neuroma formation by PRGD/PDLLA/β-TCP conduit: report of two cases.

    Yin, Yixia; Li, Binbin; Yan, Qiongjiao; Dai, Honglian; Wang, Xinyu; Huang, Jifeng; Li, Shipu

    2015-06-01

    In the field of nerve repair, one major challenge is the formation of neuroma. However, reports on both the promotion of nerve regeneration and prevention of traumatic neuroma in the clinical settings are rare in the field of nerve repair. One of the reasons could be the insufficiency in the follow-up system. We have conducted 33 cases of nerve repair using PRGD/PDLLA/β-TCP conduit without any sign of adverse reaction, especially no neuroma formation. Among them, we have selected two cases as representatives to report in this article. The first case was a patient with an upper limb nerve wound was bridged by PRGD/PDLLA/β-TCP conduit and a plate fixation was given. After nearly 3-years' follow-up, the examination results demonstrated that nerve regeneration effect was very good. When the reoperation was performed to remove the steel plate we observed a uniform structure of the regenerated nerve without the formation of neuroma, and to our delight, the implanted conduit was completely degraded 23 months after the implantation. The second case had an obsolete nerve injury with neuroma formation. After removal of the neuroma, the nerve was bridged by PRGD/PDLLA/β-TCP conduit. Follow-up examinations showed that the structure and functional recovery were improved gradually in the 10-month follow-up; no end-enlargement and any other abnormal reaction associated with the characteristic of neuroma were found. Based on our 33-case studies, we have concluded that PRGD/PDLLA/β-TCP nerve conduit could both promote nerve regeneration and prevent neuroma formation; therefore, it is a good alternative for peripheral nerve repair.

  9. The efficacy of a scaffold-free Bio 3D conduit developed from human fibroblasts on peripheral nerve regeneration in a rat sciatic nerve model

    Yurie, Hirofumi; Ikeguchi, Ryosuke; Aoyama, Tomoki; Kaizawa, Yukitoshi; Tajino, Junichi; Ito, Akira; Ohta, Souichi; Oda, Hiroki; Takeuchi, Hisataka; Akieda, Shizuka; Tsuji, Manami; Nakayama, Koichi; Matsuda, Shuichi

    2017-01-01

    Background Although autologous nerve grafting is the gold standard treatment of peripheral nerve injuries, several alternative methods have been developed, including nerve conduits that use supportive cells. However, the seeding efficacy and viability of supportive cells injected in nerve grafts remain unclear. Here, we focused on a novel completely biological, tissue-engineered, scaffold-free conduit. Methods We developed six scaffold-free conduits from human normal dermal fibroblasts using a Bio 3D Printer. Twelve adult male rats with immune deficiency underwent mid-thigh-level transection of the right sciatic nerve. The resulting 5-mm nerve gap was bridged using 8-mm Bio 3D conduits (Bio 3D group, n = 6) and silicone tube (silicone group, n = 6). Several assessments were conducted to examine nerve regeneration eight weeks post-surgery. Results Kinematic analysis revealed that the toe angle to the metatarsal bone at the final segment of the swing phase was significantly higher in the Bio 3D group than the silicone group (-35.78 ± 10.68 versus -62.48 ± 6.15, respectively; p < 0.01). Electrophysiological studies revealed significantly higher compound muscle action potential in the Bio 3D group than the silicone group (53.60 ± 26.36% versus 2.93 ± 1.84%; p < 0.01). Histological and morphological studies revealed neural cell expression in all regions of the regenerated nerves and the presence of many well-myelinated axons in the Bio 3D group. The wet muscle weight of the tibialis anterior muscle was significantly higher in the Bio 3D group than the silicone group (0.544 ± 0.063 versus 0.396 ± 0.031, respectively; p < 0.01). Conclusions We confirmed that scaffold-free Bio 3D conduits composed entirely of fibroblast cells promote nerve regeneration in a rat sciatic nerve model. PMID:28192527

  10. Scalable K-Means++

    Bahmani, Bahman; Vattani, Andrea; Kumar, Ravi; Vassilvitskii, Sergei

    2012-01-01

    Over half a century old and showing no signs of aging, k-means remains one of the most popular data processing algorithms. As is well-known, a proper initialization of k-means is crucial for obtaining a good final solution. The recently proposed k-means++ initialization algorithm achieves this, obtaining an initial set of centers that is provably close to the optimum solution. A major downside of the k-means++ is its inherent sequential nature, which limits its applicability to massive data: one must make k passes over the data to find a good initial set of centers. In this work we show how to drastically reduce the number of passes needed to obtain, in parallel, a good initialization. This is unlike prevailing efforts on parallelizing k-means that have mostly focused on the post-initialization phases of k-means. We prove that our proposed initialization algorithm k-means|| obtains a nearly optimal solution after a logarithmic number of passes, and then show that in practice a constant number of passes suffic...

  11. Mean-periodic functions

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  12. Meaning in Work Life

    Ravn, Ib

    meaningful is still lacking (Harpaz & Fu, 2002), as are definitions of key terms. Here, I define meaning as the experience that something fits into a wider context or coheres within a larger whole.     I conceptualize meaning in work life as deriving from four factors, each of which helps us contribute...... to something larger than ourselves (Seligman, 2002) through our work. Thus, a person experiences meaning in work life when she... A. is able to use her signature strengths at work (Peterson and Seligman, 2004), B. makes an important contribution to the workplace (Drucker, 1999), C. participates in a productive...

  13. Water vapor changes under global warming and the linkage to present-day interannual variabilities in CMIP5 models

    Takahashi, Hanii; Su, Hui; Jiang, Jonathan H.

    2016-12-01

    The fractional water vapor changes under global warming across 14 Coupled Model Intercomparison Project Phase 5 simulations are analyzed. We show that the mean fractional water vapor changes under global warming in the tropical upper troposphere between 300 and 100 hPa range from 12.4 to 28.0 %/K across all models while the fractional water vapor changes are about 5-8 %/K in other regions and at lower altitudes. The "upper-tropospheric amplification" of the water vapor change is primarily driven by a larger temperature increase in the upper troposphere than in the lower troposphere per degree of surface warming. The relative contributions of atmospheric temperature and relative humidity changes to the water vapor change in each model vary between 71.5 to 131.8 % and 24.8 to -20.1 %, respectively. The inter-model differences in the water vapor change is primarily caused by differences in temperature change, except over the inter-tropical convergence zone within 10°S-10°N where the model differences due to the relative humidity change are significant. Furthermore, we find that there is generally a positive correlation between the rates of water vapor change for long-tem surface warming and those on the interannual time scales. However, the rates of water vapor change under long-term warming have a systematic offset from those on the inter-annual time scales and the dominant contributor to the differences also differs for the two time scales, suggesting caution needs to be taken when inferring long-term water vapor changes from the observed interannual variations.

  14. Employment of vapor pressure data in the description of vapor-liquid equilibrium with direct method

    Morbidelli, M.; Carra, S.

    1981-07-01

    A general procedure for inserting vapor-pressure data of pure components into equations of state provides a straightforward scheme for the extension of direct methods to the study of phase equilibria of polar mixtures and of solutions containing nonvolatile electrolytes. It makes the equation of state applicable to all compounds and to the shole temperature range and more accurate in the prediction of both multicomponent and pure vapor-liquid equilibria.

  15. Soils - Mean Permeability

    Kansas Data Access and Support Center — This digital spatial data set provides information on the magnitude and spatial pattern of depth-weighted, mean soil permeability throughout the State of Kansas. The...

  16. Mean nuclear volume

    Mogensen, O.; Sørensen, Flemming Brandt; Bichel, P.

    1999-01-01

    We evaluated the following nine parameters with respect to their prognostic value in females with endometrial cancer: four stereologic parameters [mean nuclear volume (MNV), nuclear volume fraction, nuclear index and mitotic index], the immunohistochemical expression of cancer antigen (CA125...

  17. Meaning in couples relationships.

    Rodrigues T.F.

    2014-09-01

    Full Text Available Based on psycholinguistics and L. Vygotsky’s (2007 theories on sign, meaning and sense categories, as later discussed by A. Leontiev (2004, 2009, we present a case study that focuses on the intricacies of a love relationship for a woman who remained in a painful marriage. Interview material is presented in a Relational-Historical Psychology theoretical framework to provide central categories of meaning and sense. This is understood as a privileged method for apprehending the uniqueness of a human being. To segment the qualitative material, we used the “Analysis of the Nuclei of Meanings for the Apprehension of the Constitution of Sense,” by Aguiar and Ozella (2006, 2013. This approach seeks to discriminate the meanings and senses that constitute the content of a speech sample.

  18. Stats means business

    Buglear, John

    2010-01-01

    Stats Means Business is an introductory textbook written for Business, Hospitality and Tourism students who take modules on Statistics or Quantitative research methods. Recognising that most users of this book will have limited if any grounding in the subject, this book minimises technical language, provides clear definition of key terms, and gives emphasis to interpretation rather than technique.Stats Means Business enables readers to:appreciate the importance of statistical analysis in business, hospitality and tourism understand statis

  19. Outcome of Transurethral Plasmakinetic Vaporization for Benign Prostatic Hyperplasia

    Magdy El-Tabey

    2015-04-01

    Full Text Available Purpose To assess the outcome of transurethral plasmakinetic vaporization (PKVP in the management of benign prostatic hyperplasia (BPH. Patients and methods From August 2010 to May 2012, 60 patients with obstructive LUTS due to BPH were included in the study. All patients were evaluated by International Prostate Symptom Score (IPSS, general examination, digital rectal examination, PSA, routine laboratory examinations, pelvi-abdominal ultrasound, trans-rectal ultrasound, and uroflowmetry. Patients with Qmax of 8 and a prostate volume of >40 mL underwent transurethral PKVP. Results Mean age of the patients was 66.8±4.5 years. The mean times of the operation, post-operative bladder irrigation, and post-operative catheterization were 63.8±13.9 minutes, 15.2±5.7 hours, and 23.9±5.2 hours, respectively. At 3 months of follow-up, there were significant reductions in the mean IPSS from 23.4±3.5 to 9.2±3.7 (P=0.4, mean PSA from 3.03±2.2 ng/mL to 1.2±1.04 ng/mL (P value=0.02, mean post voiding residual urine from 149.8±59.5 mL to 46.9±24.1 mL (P value <0.01, and mean prostate volume from 72.8±10.3 mL to 22.7±6.1 mL (P value <0.01. Also, there was a statistically significant increase in the mean Q max. from 8.7±2.4 mL/s to 19.5±3.5 mL/s (P value <0.01. Conclusion PKVP is an effective and safe treatment option in the management of symptomatic BPH.

  20. 33 CFR 154.826 - Vapor compressors and blowers.

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor compressors and blowers....826 Vapor compressors and blowers. (a) Each inlet and outlet to a compressor or blower which handles...) Excessive shaft bearing temperature. (d) If a centrifugal compressor, fan, or lobe blower handles vapor...

  1. Vapor-modulated heat pipe for improved temperature control

    Edwards, D. K.; Eninger, J. E.; Ludeke, E. E.

    1978-01-01

    Dryout induced by vapor throttling makes control of equipment temperature less dependent on variations in sink environment. Mechanism controls flow of vapor in heat pipe by using valve in return path to build difference in pressure and also difference in saturation temperature of the vapor. In steady state, valve closes just enough to produce partial dryout that achieves required temperature drop.

  2. 21 CFR 888.4220 - Cement monomer vapor evacuator.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement monomer vapor evacuator. 888.4220 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4220 Cement monomer vapor evacuator. (a) Identification. A cement monomer vapor evacuator is a device intended for use during surgery to contain or...

  3. Effects of vapor pressure/velocity and concentration on condensation heat transfer for steam-ethanol vapor mixture

    Yan, Junjie; Yang, Yusen; Hu, Shenhua; Zhen, Kejian; Liu, Jiping [Xi' an Jiaotong University, State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an (China)

    2007-11-15

    When a steam-ethanol vapor mixture condenses on a vertical flat plate, the form of the condensate film changes and many drops are created. This non-film condensation is called pseudo-dropwise or Marangoni condensation. This paper aims to study the main influencing factors on the Marangoni condensation of steam-ethanol vapor.The factors include the ethanol concentration, vapor pressure, vapor velocity and vapor-to-surface temperature difference. The experiments show that the heat transfer coefficient has a maximum value of approximately 42 kW/m{sup 2} K when the ethanol concentration is 1%. At the low concentrations of 0.5, 1, 5.1 and 9.8%, the condensation heat transfer is greater than for pure steam. In addition, the heat transfer for all vapor mixtures increases with both the rise of vapor pressure and vapor velocity. (orig.)

  4. Effects of vapor pressure/velocity and concentration on condensation heat transfer for steam-ethanol vapor mixture

    Yan, Junjie; Yang, Yusen; Hu, Shenhua; Zhen, Kejian; Liu, Jiping

    2007-11-01

    When a steam-ethanol vapor mixture condenses on a vertical flat plate, the form of the condensate film changes and many drops are created. This non-film condensation is called pseudo-dropwise or Marangoni condensation. This paper aims to study the main influencing factors on the Marangoni condensation of steam-ethanol vapor.The factors include the ethanol concentration, vapor pressure, vapor velocity and vapor-to-surface temperature difference. The experiments show that the heat transfer coefficient has a maximum value of approximately 42 kW/m2 K when the ethanol concentration is 1%. At the low concentrations of 0.5, 1, 5.1 and 9.8%, the condensation heat transfer is greater than for pure steam. In addition, the heat transfer for all vapor mixtures increases with both the rise of vapor pressure and vapor velocity.

  5. Membrane-assisted vapor stripping: energy efficient hybrid distillation-vapor permeation process for alcohol-water separation

    BACKGROUND: Energy efficient alternatives to distillation for alcohol recovery from dilute solution are needed to improve biofuel sustainability. A process integrating steam stripping with a vapor compression step and a vapor permeation membrane separation step is proposed. The...

  6. Application of a new multiphase multicomponent volcanic conduit model with magma degassing and crystallization to Stromboli volcano.

    La Spina, Giuseppe; Burton, Mike; de'Michieli Vitturi, Mattia

    2014-05-01

    Volcanoes exhibit a wide range of eruption styles, from relatively slow effusive eruptions, generating lava flows and lava domes, to explosive eruptions, in which very large volumes of fragmented magma and volcanic gas are ejected high into the atmosphere. During an eruption, much information regarding the magma ascent dynamics can be gathered: melt and exsolved gas composition, crystal content, mass flow rate and ballistic velocities, to name just a few. Due to the lack of direct observations of the conduit itself, mathematical models for magma ascent provide invaluable tools for a better comprehension of the system. The complexity of the multiphase multicomponent gas-magma-solid system is reflected in the corresponding mathematical model; a set of non-linear hyperbolic partial differential and constitutive equations, which describe the physical system, has to be formulated and solved. The standard approach to derive governing equations for two-phase flow is based on averaging procedures, which leads to a system of governing equations in the form of mass, momentum and energy balance laws for each phase coupled with algebraic and differential source terms which represent phase interactions. For this work, we used the model presented by de' Michieli Vitturi et al. (EGU General Assembly Conference Abstracts, 2013), where a different approach based on the theory of thermodynamically compatible systems has been adopted to write the governing multiphase equations for two-phase compressible flow (with two velocities and two pressures) in the form of a conservative hyperbolic system of partial differential equations, coupled with non-differential source terms. Here, in order to better describe the multicomponent nature of the system, we extended the model adding several transport equations to the system for different crystal components and different gas species, and implementing appropriate equations of state. The constitutive equations of the model are chosen to

  7. Extracardiac conduit in total cavopulmonary connection Conduto extracardíaco na derivação cavopulmonar total

    Paulo Paredes Paulista

    2003-09-01

    Full Text Available OBJECTIVE: This study evaluates a new technique of an extracardiac conduit in total cavopulmonary connection in complex congenital heart disease. METHODS: Between May 2000 and October 2002, 18 extracardiac conduit surgeries were performed. The patients' weights ranged from 11 to 29 kilograms, the ages ranged from 1 to 12 years old and 10 patients were male. There were eight patients with tricuspid atresia, eight with univentricular heart, and two with unbalanced total atrioventricular septal defect. There were 17 patients who had been submitted to a previous palliative surgery. The surgery was performed at over 32º centigrade without aortic ischemia. Ten PTFE, 4 Hemashield and 4 bovine pericardium tubes were used with diameters ranging from 16 to 22 mm. RESULTS: There were four cases of tube thrombosis and these patients were a reoperation was performed with one death. In one patient a takedown was performed on the 69th postoperative day. There were three deaths, one due to tube thrombosis and two due to low cardiac output. CONCLUSION: Extracardiac conduit is already used for total cavopulmonary connection, but despite encouraging early results, a longer follow-up is necessary to prove its real advantages.OBJETIVO: Avaliar a utilização de conduto extracardíaco na confecção de derivação cavopulmonar total nos diferentes tipos de cardiopatias complexas nas quais está indicado este tipo de correção. MÉTODO: Entre maio de 2000 e janeiro de 2003, foram operados 18 pacientes, 10 do sexo masculino, com idades entre 1 e 12 anos e peso variando de 11 a 29 quilos. O diagnóstico principal foi atresia tricúspide em oito pacientes, conexão atrioventricular univentricular em oito e defeito total do septo atrioventricular desbalanceado em dois. Apenas um paciente foi operado sem cirurgia paliativa prévia. A operação foi realizada com emprego de circulação extracorpórea com temperatura acima de 32ºC orofaríngea e sem isquemia a

  8. Dome/Conduit inflation-deflation at Volcan de Fuego, Colima: evidence from seismic and geodetic data

    Arciniega-Ceballos, A.; Cabral-Cano, E.; Castaneda, E.; Salazar-Tlaczani, L.; DeMets, C.; Marquez-Azua, B.

    2013-12-01

    Volcan de Fuego is a strato-volcano (3860 m high) in Colima Mexico, which has been presenting high explosive activity from small to large explosive events, occasionally accompanied by pyroclastic flows, periodic dome growth and destructive phases, intense fumarole activity and degassing, during the last decade. Since June 2011 a broadband seismic and geodetic network has been operating at radial distances ranging between 1.5 and 4 km from the crater. Five stations are equipped with a Nanometrics 120 s Trillium seismometer and Trimble NetR9 GPS receiver, from which three of them include a MiniDOAS gas detection system. During the period of study eruptive activity of Volcan de Fuego has been dominated by dome growth, degassing and occasional large explosions. These events are associated with the partial dome destruction and frequent ash emissions. Preliminary analyses of two-year continuous records of broadband seismic and geodesy data have revealed dome/conduit inflation-deflation phases related to conspicuous VLP tremor in the 1-20 s period band. VLP tremor has been detected in several periods since 2011 in all stations of the network. VLP tremor may be spasmodic or a persistent signal that fluctuates both in amplitude and time. Since in volcanic areas microseismicity may cover a period range of 5 to 20 s, we analyze and characterize the noise levels considering the relative amplitude with respect to the average amplitude of microseismic noise at each station. We evaluate temporal and frequency variations of volcanic activity with respect the microseismic levels. Our results indicate that the energy of the wave field in the 1-20 s period band is dominated by volcanic activity, especially in cases associated with large eruptive events. The presence of VLP tremor correlates well with inflation-deflation phases observed in the GPS time series, with total vertical displacements of 20-40 mm. This behavior is most evident in the COPN, COPE and COLW stations, which are

  9. The generation and evolution of anisotropic gas-permeability during viscous deformation in conduit-filling ignimbrites

    Kolzenburg, Stephan; Russell, Kelly

    2015-04-01

    Gas-permeability plays a governing role in the pre-explosive pressurization of volcanic edifices. Pressurization may only occur once the total volume flux of gases emitted by an underlying magmatic or hydrothermal source exceeds the flow capacity of the permeable pathways present in the edifice. We have measured the physical properties (strain, porosity, permeability and ultrasonic wave velocities) of breadcrust bombs recovered from the deposits of the 2350 B.P. eruption of Mt Meager, BC, Canada. These rocks represent a conduit-infilling pyroclastic breccia that underwent various degrees of welding and deformation and present a remarkable opportunity to constrain the nature and timescale of mechanical processes operating within explosive volcanic conduits during repose periods between eruptive cycles. Here we present data from permeability measurements along the directions of maximum and minimum shortening which help quantifying the effect of vesicle microstructure on permeability. Permeability is measured by applying a range of confining pressures (between 3.4 and 17.2 MPa) to each sample and imposing a constant head (of 0.2 to 3.5 MPa) across the sample. The permeability is then determined using a modified version of Darcy's law applicable to compressible fluids. These rocks display a profound directionality in the measured physical properties resulting from the deformation-induced fabric. For all samples the permeability across the elongation fabric is highly correlated to the sample porosity whereas along the elongation fabric there is little effect of porosity on permeability. At porosity values of about 20% the permeability seems to reach a minimum at 10-16 m2 and does not change significantly with further reduction of porosity. Further, the effect of confining pressure on the permeability of these samples appears to be more pronounced across the elongation fabric than along the elongation fabric. The deformation fabric has a significant effect on the gas

  10. The experimental and numerical investigation of a grooved vapor chamber

    Zhang Ming [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Education Commission, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022 (China); Liu Zhongliang [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Education Commission, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022 (China)], E-mail: liuzhl@bjut.edu.cn; Ma Guoyuan [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Education Commission, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022 (China)

    2009-02-15

    An effective thermal spreader can achieve more uniform heat flux distribution and thus enhance heat dissipation of heat sinks. Vapor chamber is one of highly effective thermal spreaders. In this paper, a novel grooved vapor chamber was designed. The grooved structure of the vapor chamber can improve its axial and radial heat transfer and also can form the capillary loop between condensation and evaporation surfaces. The effect of heat flux, filling amount and gravity to the performance of this vapor chamber is studied by experiment. From experiment, we also obtained the best filling amount of this grooved vapor chamber. By comparing the thermal resistance of a solid copper plate with that of the vapor chamber, it is suggested that the critical heat flux condition should be maintained to use vapor chamber as efficient thermal spreaders for electronics cooling. A two-dimensional heat and mass transfer model for the grooved vapor chamber is developed. The numerical simulation results show the thickness distribution of liquid film in the grooves is not uniform. The temperature and velocity field in vapor chamber are obtained. The thickness of the liquid film in groove is mainly influenced by pressure of vapor and liquid beside liquid-vapor interface. The thin liquid film in heat source region can enhance the performance of vapor chamber, but if the starting point of liquid film is backward beyond the heat source region, the vapor chamber will dry out easily. The optimal filling ratio should maintain steady thin liquid film in heat source region of vapor chamber. The vapor condenses on whole condensation surface, so that the condensation surface achieves great uniform temperature distribution. By comparing the experimental results with numerical simulation results, the reliability of the numerical model can be verified.

  11. Evaluative Meaning in Translation

    Primož Jurko

    2015-12-01

    Full Text Available Evaluative meaning is frequently understood as a form of connotation, pertaining to single lexical items. However, the term has recently been applied also to longer stretches of text, spanning several words. The paper generally deals with the latter aspect and provides a corpus-driven analysis of several Slovene and English phrases that may appear semantically neutral, yet turn out to be heavily non-neutral in terms of their semantic properties. After a short introduction of the main approaches to the topic, including its dilemmas, the paper focuses on the L1-into-L2 translation of such strings, with particular emphasis on proper rendering of the evaluative meaning. While further research is warranted into the matter, the work presented here attests to the complex and ubiquitous nature of the Sinclairian extended unit of meaning.

  12. Q Conversion Factor Models for Estimating Precipitable Water Vapor for Turkey

    Deniz, Ilke; Mekik, Cetin; Gurbuz, Gokhan

    2015-04-01

    Global Navigation Satellite Systems (GNSS) have recently proved to be one of the crucial tools for determining continuous and precise precipitable water vapor (GNSS-MET networks). GNSS, especially CORS networks such as CORS-TR (the Turkish Network-RTK), provide high temporal and spatial accuracy for the wet tropospheric zenith delays which are then converted to the precipitable water vapor due to the fact that they can operate in all weather conditions continuously and economically. The accuracy of wet tropospheric zenith delay highly depends on the accuracy of precipitable water vapor content in the troposphere. Therefore, the precipitable water vapor is an important element of the tropospheric zenith delay. A number of studies can be found in the literature on the determination of the precipitable water vapor from the tropospheric zenith delay. Studies of Hogg showed that when the precipitable water vapor is known, the tropospheric zenith delay can be computed. Askne and Nodius have developed fundamental equations between the wet tropospheric zenith delay and the precipitable water vapor from the equation of the index of refraction in the troposphere. Furthermore, Bevis have developed a linear regression model to determine the weighted mean temperature (Tm) depending on the surface temperature (Ts) in Askne and Nodius studies. For this reason, nearly 9000 radiosonde profiles in USA were analyzed and the coefficients calculated. Similarly, there are other studies on the calculation of those coefficients for different regions: Solbrig for Germany, Liou for Taiwan, Jihyun for South Korea, Dongseob for North Korea, Suresh Raju for India, Boutiouta and Lahcene for Algeria, Bokoye for Canada, Baltink for Netherlands and Baltic, Bock for Africa. It is stated that the weighted mean temperature can be found with a root mean square error of ±2-5 K. In addition, there are studies on the calculation of the coefficients globally. Another model for the determination of

  13. Computing meaning v.4

    Bunt, Harry; Pulman, Stephen

    2013-01-01

    This book is a collection of papers by leading researchers in computational semantics. It presents a state-of-the-art overview of recent and current research in computational semantics, including descriptions of new methods for constructing and improving resources for semantic computation, such as WordNet, VerbNet, and semantically annotated corpora. It also presents new statistical methods in semantic computation, such as the application of distributional semantics in the compositional calculation of sentence meanings. Computing the meaning of sentences, texts, and spoken or texted dialogue i

  14. Intersubjective meaning making

    Davidsen, Jacob

    of single-touch screen interaction among 8-9 year-old children presented here, shows that while the constraints of single-touch screens does not support equality of interaction at the verbal and the physical level, there seems to be an intersubjective learning outcome. More precisely, the constraints...... of single-touch screens offer support for intersubjective meaning making in its ability of constraining the interaction. By presenting a short embodied interaction analysis of 22 seconds of collaboration, I illustrate how an embodied interaction perspective on intersubjective meaning making can tell...... a different story about touch-screen supported collaborative learning....

  15. Mean Field ICA

    Petersen, Kaare Brandt

    2006-01-01

    This thesis describes investigations and improvements of a technique for Independent Component Analysis (ICA), called "Mean Field ICA". The main focus of the thesis is the optimization part of the algorithm, the so-called "EM algorithm". Using different approaches it is demonstrated that the EM...... Gradient Recipe is applicable to a wide selection of models. Furthermore, the Mean Field ICA model is extended to incorporate ltering over time in a so-called "convolutive ICA" model. Finally, by using mixture of Gaussians as source priors, the generative and ltering approach to ICA is compared...

  16. Atomic vapor spectroscopy in integrated photonic structures

    Ritter, Ralf; Pernice, Wolfram; Kübler, Harald; Pfau, Tilman; Löw, Robert

    2015-01-01

    We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.

  17. Modelling vaporous cavitation on fluid transients

    Shu, Jian-Jun

    2014-01-01

    A comprehensive study of the problem of modelling vaporous cavitation in transmission lines is presented. The two-phase homogeneous equilibrium vaporous cavitation model which has been developed is compared with the conventional column separation model. The latter predicts unrealistically high pressure spikes because of a conflict arising from the prediction of negative cavity sizes if the pressure is not permitted to fall below the vapour pressure, or the prediction of negative absolute pressures if the cavity size remains positive. This is verified by a comparison of predictions with previously published experimental results on upstream, midstream and downstream cavitation. The new model has been extended to include frequency-dependent friction. The characteristics predicted by the frequency-dependent friction model show close correspondence with experimental data.

  18. Vapor Pressure of Pentafluoroethane and Trifluoroiodomethane

    Zhang Chang; Duan Yuanyuan; Shi Lin; Zhu Mingshan; Han Lizhong

    2001-01-01

    Pentafluoroethane (HFC-125) and trifluoroiodomethane (CF3I) are considered as promising refrigerant alternatives, especially as components in mixtures, to replace CFCs or HCFCs. Effective uses of HFC-125 and CF3I require that the thermophysical properties be accurately measured. In the present work, vapor pressure data of HFC-125 and CF3I have been measured in the temperature range from 292 to 337 K and 288 to 336 K,respectively. Maximum total pressure uncertainty of HFC-125 data is estimated to be within ±1.2 kPa and ±780 Pa for CF3I. Based on the data set and literature values, the vapor pressure equations for HFC-125 and CF3I have been developed. The relative deviation of the equations correlate the measurements within 0.022% for HFC-125 and 0.068% for CF3I, respectively.

  19. The toxicity of inhaled methanol vapors

    Kavet, R.; Nauss, K.M. (Environmental Research Information, Inc., Palo Alto, CA (USA))

    1990-01-01

    Methanol could become a major automotive fuel in the U.S., and its use may result in increased exposure of the public to methanol vapor. Nearly all of the available information on methanol toxicity in humans relates to the consequences of acute, rather than chronic, exposures. Acute methanol toxicity evolves in a well-understood pattern and consists of an uncompensated metabolic acidosis with superimposed toxicity to the visual system. The toxic properties of methanol are rooted in the factors that govern both the conversion of methanol to formic acid and the subsequent metabolism of formate to carbon dioxide in the folate pathway. In short, the toxic syndrome sets in if formate generation continues at a rate that exceeds its rate of metabolism. Current evidence indicates that formate accumulation will not challenge the metabolic capacity of the folate pathway at the anticipated levels of exposure to automotive methanol vapor.117 references.

  20. Heat flow in vapor dominated areas of the Yellowstone Plateau volcanic field: implications for the thermal budget of the Yellowstone Caldera

    Hurwitz, Shaul; Harris, Robert; Werner, Cynthia Anne; Murphy, Fred

    2012-01-01

    Characterizing the vigor of magmatic activity in Yellowstone requires knowledge of the mechanisms and rates of heat transport between magma and the ground surface. We present results from a heat flow study in two vapor dominated, acid-sulfate thermal areas in the Yellowstone Caldera, the 0.11 km2 Obsidian Pool Thermal Area (OPTA) and the 0.25 km2 Solfatara Plateau Thermal Area (SPTA). Conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at >600 locations and from laboratory measurements of soil properties. The conductive heat output is 3.6 ± 0.4 MW and 7.5 ± 0.4 MW from the OPTA and the SPTA, respectively. The advective heat output from soils is 1.3 ± 0.3 MW and 1.2 ± 0.3 MW from the OPTA and the SPTA, respectively and the heat output from thermal pools in the OPTA is 6.8 ± 1.4 MW. These estimates result in a total heat output of 11.8 ± 1.4 MW and 8.8 ± 0.4 MW from OPTA and SPTA, respectively. Focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor. Extrapolation of the average heat flux from the OPTA (103 ± 2 W·m−2) and SPTA (35 ± 3 W·m−2) to the ~35 km2 of vapor dominated areas in Yellowstone yields 3.6 and 1.2 GW, respectively, which is less than the total heat output transported by steam from the Yellowstone Caldera as estimated by the chloride inventory method (4.0 to 8.0 GW).

  1. Vapor-phase heat-transport system

    Hedstrom, J.C.

    1983-01-01

    A vapor-phase heat-transport system is being tested in one of the passive test cells at Los Alamos. The system consists of one selective-surface collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by gravity or with a pump. Results from several operating configurations are presented, together with a comparison with other passive systems. A new self-pumping concept is presented.

  2. Kinetics of metal salt vapor lasers

    Kazarian, M.A.; Trofimov, A.N.

    1979-02-01

    A kinetic model is constructed for lasers operating on metal salt vapors. Different operating regimes of these lasers are considered, and it is shown that during transition from double-pulse regime to pulse-train regime or regular-pulse regime it is necessary to take into account accumulation effects. Numerical calculations for copper halogenides are carried out. It is shown how different operating regimes have widely different lasing conditions. This is due to the accumulation effects mentioned above.

  3. Vapor Crystal Growth (VCG) experiment Cell

    1992-01-01

    The image shows a test cell of Crystal Growth experiment inside the Vapor Crystal Growth System (VCGS) furnace aboard the STS-42, International Microgravity Laboratory-1 (IML-1), mission. The goal of IML-1, a pressurized marned Spacelab module, was to explore in depth the complex effects of weightlessness of living organisms and materials processing. More than 200 scientists from 16 countires participated in the investigations.

  4. Making Ceramic Fibers By Chemical Vapor

    Revankar, Vithal V. S.; Hlavacek, Vladimir

    1994-01-01

    Research and development of fabrication techniques for chemical vapor deposition (CVD) of ceramic fibers presented in two reports. Fibers of SiC, TiB2, TiC, B4C, and CrB2 intended for use as reinforcements in metal-matrix composite materials. CVD offers important advantages over other processes: fibers purer and stronger and processed at temperatures below melting points of constituent materials.

  5. Laser Velocimetry of Chemical Vapor Deposition Flows

    1993-01-01

    Laser velocimetry (LV) is being used to measure the gas flows in chemical vapor deposition (CVD) reactors. These gas flow measurements can be used to improve industrial processes in semiconductor and optical layer deposition and to validate numerical models. Visible in the center of the picture is the graphite susceptor glowing orange-hot at 600 degrees C. It is inductively heated via the copper cool surrounding the glass reactor.

  6. The meaning of talent

    Raquel Lorenzo

    2006-01-01

    Full Text Available The knowledge society gives a remarkable role to human potentialities into organizations. For this reason has emerged talent management. But it is necessary to know its meaning to put on practice programs. In this paper, the author analyzes different points of views about this topic.

  7. PR Means Positive Results.

    Foree, Marilyn

    1992-01-01

    Describes the advantages of public relations to a school music program. Suggests that, to succeed, a music program must have the support of school administrators, teachers, parents, and students alike. Recommends means of attracting support from the four groups. Stresses the importance of effective local publicity. (SG)

  8. Meaning = Information + Evolution

    Rovelli, Carlo

    2016-01-01

    Notions like meaning, signal, intentionality, are difficult to relate to a physical word. I study a purely physical definition of "meaningful information", from which these notions can be derived. It is inspired by a model recently illustrated by Kolchinsky and Wolpert, and improves on Dretske classic work on the relation between knowledge and information. I discuss what makes a physical process into a "signal".

  9. Meaning in Context

    Christiansen, Henning; Dahl, Veronica

    2005-01-01

    A model for context-dependent natural language semantics is proposed and formalized in terms of possible worlds. The meaning of a sentence depends on context and at the same time affects that context representing the knowledge about the world collected from a discourse. The model fits well...

  10. Conversations across Meaning Variance

    Cordero, Alberto

    2013-01-01

    Progressive interpretations of scientific theories have long been denounced as naive, because of the inescapability of meaning variance. The charge reportedly applies to recent realist moves that focus on theory-parts rather than whole theories. This paper considers the question of what "theory-parts" of epistemic significance (if any) relevantly…

  11. The meaning of curvature

    diffusion to volume growth. We are e.g. interested in obtaining precise bounds for mean exit times for Brownian motions and for isoperimetric inequalities. One way to obtain such bounds are via curvature controlled comparison with corresponding values in constant curvature spaces and in other tailor-made so...

  12. Engagement Means Everyone

    Patton, Carol

    2012-01-01

    Employee engagement is not just HR's responsibility. While HR is responsible for the process of measuring and driving engagement, improving it is actually everyone's responsibility. And that means reducing the barriers to productivity to drive business performance. Training departments can play a pivotal role. Their job is to enhance curriculum or…

  13. The Measurement of Meaning.

    Osgood, Charles E.; And Others

    The problem of measuring meaning viewed strictly as a psychological conception via the application of semantic differential theory is presented in this study. The first half of the book discusses theoretical background, logic of semantic measurement, basic factor analysis research, and a critical scientific evaluation of measuring procedures. The…

  14. Nuclear vapor thermal reactor propulsion technology

    Maya, Isaac; Diaz, Nils J.; Dugan, Edward T.; Watanabe, Yoichi; McClanahan, James A.; Wen-Hsiung Tu, Carman, Robert L.

    1993-01-01

    The conceptual design of a nuclear rocket based on the vapor core reactor is presented. The Nuclear Vapor Thermal Rocket (NVTR) offers the potential for a specific impulse of 1000 to 1200 s at thrust-to-weight ratios of 1 to 2. The design is based on NERVA geometry and systems with the solid fuel replaced by uranium tetrafluoride (UF4) vapor. The closed-loop core does not rely on hydrodynamic confinement of the fuel. The hydrogen propellant is separated from the UF4 fuel gas by graphite structure. The hydrogen is maintained at high pressure (˜100 atm), and exits the core at 3,100 K to 3,500 K. Zirconium carbide and hafnium carbide coatings are used to protect the hot graphite from the hydrogen. The core is surrounded by beryllium oxide reflector. The nuclear reactor core has been integrated into a 75 klb engine design using an expander cycle and dual turbopumps. The NVTR offers the potential for an incremental technology development pathway to high performance gas core reactors. Since the fuel is readily available, it also offers advantages in the initial cost of development, as it will not require major expenditures for fuel development.

  15. Distribution of Water Vapor in Molecular Clouds

    Melnick, Gary J; Snell, Ronald L; Bergin, Edwin A; Hollenbach, David J; Kaufman, Michael J; Li, Di; Neufeld, David A

    2010-01-01

    We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water vapor measured toward 77 spatial positions along the face-on Orion ridge, excluding positions surrounding the outflow associated with BN/KL and IRc2, display integrated intensities that correlate strongly with known cloud surface tracers such as CN, C2H, 13CO J =5-4, and HCN, and less well with the volume tracer N2H+. Moreover, at total column densities corresponding to Av < 15 mag., the ratio of H2O to C18O integrated intensities shows a clear rise approaching the cloud surface. We show that this behavior cannot be accounted for by either optical depth or excitation effects, but suggests that gas-phase water abundances fall at large Av. These results are important as they affect measures of the true water-vapor abundance in molecular clouds by highlighting the limitations...

  16. Vapor Sensing Theoretical Study on Optical Microcavities

    ZHANG Le-xin; ZHANG Ran; LI Zhi-quan

    2007-01-01

    When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors.

  17. Combined rankine and vapor compression cycles

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2005-04-19

    An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

  18. Water vapor release from biomass combustion

    R. S. Parmar

    2008-10-01

    Full Text Available We report on the emission of water vapor from biomass combustion. Concurrent measurements of carbon monoxide and carbon dioxide are used to scale the concentrations of water vapor found, and are referenced to carbon in the biomass. The investigated fuel types include hardwood (oak and African musasa, softwood (pine and spruce, partly with green needles, and African savanna grass. The session-averaged ratio of H2O to the sum of CO and CO2 in the emissions from 16 combustion experiments ranged from 1.2 to 3.7, indicating the presence of water that is not chemically bound. This non-bound biomass moisture content ranged from 33% in the dry African hardwood, musasa, to 220% in fresh pine branches with needles. The moisture content from fresh biomass contributes significantly to the water vapor in biomass burning emissions, and its influence on the behavior of fire plumes and pyro-cumulus clouds needs to be evaluated.

  19. Physical Vapor Deposition of Thin Films

    Mahan, John E.

    2000-01-01

    A unified treatment of the theories, data, and technologies underlying physical vapor deposition methods With electronic, optical, and magnetic coating technologies increasingly dominating manufacturing in the high-tech industries, there is a growing need for expertise in physical vapor deposition of thin films. This important new work provides researchers and engineers in this field with the information they need to tackle thin film processes in the real world. Presenting a cohesive, thoroughly developed treatment of both fundamental and applied topics, Physical Vapor Deposition of Thin Films incorporates many critical results from across the literature as it imparts a working knowledge of a variety of present-day techniques. Numerous worked examples, extensive references, and more than 100 illustrations and photographs accompany coverage of: * Thermal evaporation, sputtering, and pulsed laser deposition techniques * Key theories and phenomena, including the kinetic theory of gases, adsorption and condensation, high-vacuum pumping dynamics, and sputtering discharges * Trends in sputter yield data and a new simplified collisional model of sputter yield for pure element targets * Quantitative models for film deposition rate, thickness profiles, and thermalization of the sputtered beam

  20. Experimental Study on Unconfined Vapor Cloud Explosion

    毕明树; ABULITI; Abudula

    2003-01-01

    An experimental system was setup to study the pressure field of unconfined vapor cloud explosions.The semi-spherical vapor clouds were formed by slotted 0.02mm polyethylene film.In the Center of the cloud was an ignition electrode that met ISO6164"Explosion protection System" and NFPA68 "Guide for Venting of Deflagrations". A data-acquisition system,with dymame responding time less than 0.001s with 0.5% accuracy,recorded the pressure-time diagram of acetylene-air mixture explosion with stoichiometrical ratio.The initial cloud diameters varied from 60cm to 300cm.Based on the analysis of experimental data,the quantitative relationship is obtained for the cloud explosion pressure,the cloud radius and the distance from ignition point .Present results provide a useful way to evaluate the building damage caused by unconfined vapor cloud explosions and to determine the indispensable explosion grade in the application of multi-energy model.

  1. Water vapor distribution in protoplanetary disks

    Du, Fujun

    2014-01-01

    Water vapor has been detected in protoplanetary disks. In this work we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Lyman alpha photons, since the Lyman alpha line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more ...

  2. Steady State Vapor Bubble in Pool Boiling

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C.; Maroo, Shalabh C.

    2016-02-01

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  3. Designing polymer surfaces via vapor deposition

    Ayse Asatekin

    2010-05-01

    Full Text Available Chemical Vapor Deposition (CVD methods significantly augment the capabilities of traditional surface modification techniques for designing polymeric surfaces. In CVD polymerization, the monomer(s are delivered to the surface through the vapor phase and then undergo simultaneous polymerization and thin film formation. By eliminating the need to dissolve macromolecules, CVD enables insoluble polymers to be coated and prevents solvent damage to the substrate. Since de-wetting and surface tension effects are absent, CVD coatings conform to the geometry of the underlying substrate. Hence, CVD polymers can be readily applied to virtually any substrate: organic, inorganic, rigid, flexible, planar, three-dimensional, dense, or porous. CVD methods integrate readily with other vacuum processes used to fabricate patterned surfaces and devices. CVD film growth proceeds from the substrate up, allowing for interfacial engineering, real-time monitoring, thickness control, and the synthesis of films with graded composition. This article focuses on two CVD polymerization methods that closely translate solution chemistry to vapor deposition; initiated CVD and oxidative CVD. The basic concepts underlying these methods and the resultant advantages over other thin film coating techniques are described, along with selected applications where CVD polymers are an enabling technology.

  4. Improving prediction of vapor-liquid equilibrium with modified HVOS-PR-UNIFAC model by revision of group interaction parameters

    XUE Rong-shu; LI Yan-jiao; WANG Xiao-qing; TAN Shi-yu; WEI Shun-an

    2007-01-01

    Quantitative description of vapor-liquid equilibrium is very useful for designing separation processes. In this study, we combined the Peng-Robinson equation and the Huron-Vidal-Orbey-Sandler mixing rule into a modified UNIFAC model for the improvement of predicting vapor-liquid equilibria. The predictions of vapor-liquid equilibria for 62 systems including alcoholalkane, alcohol-benzene, and amine-water systems demonstrate that the revised parameters remarkably improve the prediction accuracy for many systems. Especially for amine-water system, the mean deviation of components decreases from 0.094 to 0.021, and the mean deviation of pressure from 22.45% to 4.41%.

  5. Fibro-porous poliglecaprone/polycaprolactone conduits: synergistic effect of composition and in vitro degradation on mechanical properties.

    Patel, Harsh N; Garcia, Roman; Schindler, Carrie; Dean, Derrick; Pogwizd, Steven M; Singh, Raj; Vohra, Yogesh K; Thomas, Vinoy

    2015-04-01

    Blends of poliglecaprone (PGC) and polycaprolactone (PCL) of varying compositions were electrospun into tubular conduits and their mechanical, morphological, thermal and in vitro degradation properties were evaluated under simulated physiological conditions. Generally, mechanical strength, modulus and hydrophilic nature were enhanced by the addition of PGC to PCL. An in vitro degradation study in phosphate-buffered saline (pH 7.3) was carried out for up to 1 month to understand the hydrolytic degradation effect on the mechanical properties in both the longitudinal and circumferential directions. Pure PCL and 4:1 PCL/PGC blend scaffolds exhibited considerable elastic stiffening after a 1 month in vitro degradation. Fourier transform infrared spectroscopic and DSC techniques were used to understand the degradation behavior and the changes in structure and crystallinity of the polymeric blends. A 3:1 PCL/PGC blend was concluded to be a judicious blend composition for tubular grafts based on overall results on the mechanical properties and performance after a 1 month in vitro degradation study.

  6. A HUVEC line with a stable expression of the VEGF121 gene to achieve complete endothelialization of blood conduits.

    Liu, L-S; Wei, D-H; Tang, C-K; Wang, G-X; Zhang, S-C; Yin, W-D; Yang, Y-Z; Legrand, A-P; Guidoin, R

    2007-01-01

    The purpose of this investigation was to establish monoclonal cell lines of HUVEC with the stable expression of the VEGF(121) gene. Such cells are likely to better adhere to the luminal surface of stents or grafts and to promote a complete endothelialization. The eukaryotic expression vector PCD(2)-VEGF(121) was transfected into cell lines of HUVEC mediated by lipofect AMINE. The positive clones were obtained by the screening of G(418). The transcription and expression of the VEGF gene were investigated by RT-PCR and immunocytochemistry, respectively. The experiment of Miles was applied for the assay of the biological activity of the protein of the VEGF produced by the HUVEC lines with transfected PCD(2)-VEGF(121). The growth curve was made for comparison with that of non-transfected HUVEC line cells. The positive clone cells from which transcripted the mRNA of VEGF(121) gene were obtained by RT-PCR. The positive results of the immunocytochemistry were found and the high biological activity of VEGF in the media was detected in the positive clone cells only. The time to achieve the multiplication of the positive clone cells by a factor of 2 was shorter than that of the non-transfected HUVEC line calculated from the growth curve. The HUVEC line of monoclonal cells with the stable expression of VEGF(121) gene has been established successfully and can be employed on the luminal surfaces of foreign blood conduits.

  7. Acceleration of Peripheral Nerve Regeneration through Asymmetrically Porous Nerve Guide Conduit Applied with Biological/Physical Stimulation

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa

    2013-01-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve. PMID:23859225

  8. In Vivo Evaluation of Nerve Guidance Conduits Comprised of a Salicylic Acid-based Poly(anhydride-ester) Blend

    Lee, Yong Soo

    Unlike the central nervous system, peripheral nervous system can regenerate from injury. However, without surgical intervention, the results are often poor. Autologous nerve grafting is the golden standard for repairing peripheral nerve injury; but limited donor availability and donor site morbidity led researchers to seek alternative methods. Among the many alternative treatment options, synthetic nerve guidance conduits (NGCs) have been most actively developed. The goal of NGCs is to serve as a physical scaffold that aids the axonal regeneration process while preventing scar tissue formation that interferes with regeneration. Biocompatible and biodegradable NGCs would provide additional benefits: minimize foreign body reaction and avoid secondary surgeries to remove NGCs. We developed a unique NGC that incorporated the characteristics described above and can release an anti-inflammatory drug, salicylic acid. In this work, in vivo assays were performed to evaluate NGCs fabricated from a poly(anhydride-ester) blend. To further assist in the regeneration process, bovine native collagen type I hydrogel were inserted into the NGCs lumen which was then implanted in femoral nerve of mice for up to 16 weeks. These studies demonstrated in vivo biodegradability, biocompatibility, and axonal regeneration following an injury to the peripheral nerve. These studies provide greater insights into the importance of designing NGCs and how they aid in regeneration and functional recovery of subjects.

  9. Salicylic acid-based poly(anhydride-ester) nerve guidance conduits: Impact of localized drug release on nerve regeneration.

    Lee, Yong S; Griffin, Jeremy; Masand, Shirley N; Shreiber, David I; Uhrich, Kathryn E

    2016-04-01

    Nerve guidance conduits (NGCs) can serve as physical scaffolds aligning and supporting regenerating cells while preventing scar tissue formation that often interferes with the regeneration process. Numerous studies have focused on functionalizing NGCs with neurotrophic factors, for example, to support nerve regeneration over longer gaps, but few directly incorporate therapeutic agents. Herein, we fabricated NGCs from a polyanhydride comprised of salicylic acid (SA), a nonsteroidal anti-inflammatory drug, then performed in vitro and in vivo assays. In vitro studies included cytotoxicity, anti-inflammatory response, and NGC porosity measurements. To prepare for implantation, type I collagen hydrogels were used as NGC luminal fillers to further enhance the axonal regeneration process. For the in vivo studies, SA-NGCs were implanted in femoral nerves of mice for 16 weeks and evaluated for functional recovery. The SA-based NGCs functioned as both a drug delivery vehicle capable of reducing inflammation and scar tissue formation because of SA release as well as a tissue scaffold that promotes peripheral nerve regeneration and functional recovery.

  10. Follicular dendritic cells, conduits, lymphatic vessels, and high endothelial venules in tertiary lymphoid organs: Parallels with lymph node stroma

    Sharon eStranford

    2012-11-01

    Full Text Available In this communication, the contribution of stromal, or non-hematopoietic, cells to the structure and function of lymph nodes (LNs, as canonical secondary lymphoid organs (SLOs, is compared to that of tertiary lymphoid tissue or organs (TLOs, also known as ectopic lymphoid tissues. TLOs can arise in non-lymphoid organs during chronic inflammation, as a result of autoimmune responses, graft rejection, atherosclerosis, microbial infection, and cancer. The stromal components found in SLOs including follicular dendritic cells, fibroblast reticular cells, lymphatic vessels, and high endothelial venules and possibly conduits are present in TLOs; their molecular regulation mimics that of LNs. Advances in visualization techniques and the development of transgenic mice that permit in vivo real time imaging of these structures will facilitate elucidation of their precise functions in the context of chronic inflammation. A clearer understanding of the inflammatory signals that drive non lymphoid stromal cells to reorganize into TLOs could allow the design of therapeutic interventions to impede the progression of autoimmune activity, or alternatively, to enhance anti-tumor responses.

  11. Acceleration of peripheral nerve regeneration through asymmetrically porous nerve guide conduit applied with biological/physical stimulation.

    Kim, Jin Rae; Oh, Se Heang; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2013-12-01

    Sufficient functional restoration of damaged peripheral nerves is a big clinical challenge. In this study, a nerve guide conduit (NGC) with selective permeability was prepared by rolling an asymmetrically porous polycaprolactone/Pluronic F127 membrane fabricated using a novel immersion precipitation method. Dual stimulation (nerve growth factor [NGF] as a biological stimulus and low-intensity pulse ultrasound [US] as a physical stimulus) was adapted to enhance nerve regeneration through an NGC. The animal study revealed that each stimulation (NGF or US) has a positive effect to promote the peripheral nerve regeneration through the NGC, however, the US-stimulated NGC group allowed more accelerated nerve regeneration compared with the NGF-stimulated group. The NGC group that received dual stimulation (NGF and US) showed more effective nerve regeneration behavior than the groups that received a single stimulation (NGF or US). The asymmetrically porous NGC with dual NGF and US stimulation may be a promising strategy for the clinical treatment of delayed and insufficient functional recovery of a peripheral nerve.

  12. Modeling of Vapor-Liquid-Solid Equilibria in Acidic Aqueous Solutions

    Christensen, Søren Gregers; Thomsen, Kaj

    2003-01-01

    The phase behavior (vapor - liquid equilibria (VLE) and solid - liquid equilibria (SLE)) and thermal properties of aqueous solutions of ions like (K+, Na+, NH4+, Ca2+, Cl-) in the presence of phosphoric acid (H3PO4, H2PO4-, HPO42- ) and nitric acid (HNO3, NO3-) are described by means of the Exten......The phase behavior (vapor - liquid equilibria (VLE) and solid - liquid equilibria (SLE)) and thermal properties of aqueous solutions of ions like (K+, Na+, NH4+, Ca2+, Cl-) in the presence of phosphoric acid (H3PO4, H2PO4-, HPO42- ) and nitric acid (HNO3, NO3-) are described by means...

  13. Differential absorption lidar measurements of atmospheric water vapor using a pseudonoise code modulated AlGaAs laser. Thesis

    Rall, Jonathan A. R.

    1994-01-01

    Lidar measurements using pseudonoise code modulated AlGaAs lasers are reported. Horizontal path lidar measurements were made at night to terrestrial targets at ranges of 5 and 13 km with 35 mW of average power and integration times of one second. Cloud and aerosol lidar measurements were made to thin cirrus clouds at 13 km altitude with Rayleigh (molecular) backscatter evident up to 9 km. Average transmitter power was 35 mW and measurement integration time was 20 minutes. An AlGaAs laser was used to characterize spectral properties of water vapor absorption lines at 811.617, 816.024, and 815.769 nm in a multipass absorption cell using derivative spectroscopy techniques. Frequency locking of an AlGaAs laser to a water vapor absorption line was achieved with a laser center frequency stability measured to better than one-fifth of the water vapor Doppler linewidth over several minutes. Differential absorption lidar measurements of atmospheric water vapor were made in both integrated path and range-resolved modes using an externally modulated AlGaAs laser. Mean water vapor number density was estimated from both integrated path and range-resolved DIAL measurements and agreed with measured humidity values to within 6.5 percent and 20 percent, respectively. Error sources were identified and their effects on estimates of water vapor number density calculated.

  14. Finding organic vapors - a Monte Carlo approach

    Vuollekoski, Henri; Boy, Michael; Kerminen, Veli-Matti; Kulmala, Markku

    2010-05-01

    Aerosols have an important role in regulating the climate both directly by absorbing and scattering solar radiation, as well as indirectly by acting as cloud condensation nuclei. While it is known that their net effect on radiative forcing is negative, several key aspects remain mysterious. There exist plenty of known primary sources of particles due to both natural and man-made origin - for example desert dust, volcanic activity and tire debris. On the other hand, it has been shown that the formation of secondary particles, by nucleation from precursor vapors, is a frequent, global phenomenon. However, the very earliest steps in new particle formation - nucleation and early growth by condensation - have many big question marks on them. While several studies have indicated the importance of a sufficient concentration of sulphuric acid vapor for the process, it has also been noted that this is usually not enough. Heads have therefore turned to organic vapors, which in their multitude could explain various observed characteristics of new particle formation. But alas, the vast number of organic compounds, their complex chemistry and properties that make them difficult to measure, have complicated the quantifying task. Nevertheless, evidence of organic contribution in particles of all size classes has been found. In particular, a significant organic constituent in the very finest particles suggests the presence of a high concentration of very low-volatile organic vapors. In this study, new particle formation in the boreal forest environment of Hyytiälä, Finland, is investigated in a process model. Our goal is to quantify the concentration, to find the diurnal profile and to get hints of the identity of some organic vapors taking part in new particle formation. Previous studies on the subject have relied on data analysis of the growth rate of the observed particles. However, due to the coarse nature of the methods used to calculate growth rates, this approach has its

  15. Convection mixte lors de l'écoulement d'un fluide de Bingham au sein d'une conduite cylindrique horizontale

    N. LABSI

    2015-03-01

    Full Text Available La présente étude traite du transfert thermique en mode de convection mixte lors de l'écoulement d'un fluide viscoplastique de Bingham au sein d'une conduite cylindrique horizontale à section droite circulaire, maintenue à température constante et uniforme. Le travail numérique, basé sur la méthode des volumes finis, se focalise sur l'impact de l'intensité des forces de poussée sur le comportement hydrodynamique et thermique de l'écoulement. Les résultats montrent que la structure de l'écoulement se modifie avec l'augmentation du nombre de Grashof. Cette augmentation entraine l'amélioration du transfert thermique et l'augmentation de a perte de charge et ce, dans la zone intermédiaire de la conduite.

  16. Using the stress function in the flow of generalized Newtonian fluids through conduits with non-circular or multiply connected cross sections

    Sochi, Taha

    2015-01-01

    We investigate the possibility that the spatial dependency of stress in generalized Newtonian flow systems is a function of the applied pressure field and the conduit geometry but not of the fluid rheology. This possibility is well established for the case of a one-dimensional flow through simply connected regions, specifically tubes of circular uniform cross sections and plane thin slits. If it can also be established for the more general case of generalized Newtonian flow through non-circular or multiply connected geometries, such as the two-dimensional flow through conduits of rectangular or elliptical cross sections or the flow through annular circular pipes, then analytical or semi-analytical or highly accurate numerical solutions; regarding stress, rate of strain, velocity profile and volumetric flow rate; for these geometries can be obtained from the stress function, which can be easily obtained from the Newtonian case, in combination with the constitutive rheological relation for the particular non-Ne...

  17. Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor Deposition

    2011-01-01

    International audience; Rare earth (RE) doped silica-based optical fibers with transparent glass ceramic (TGC) core was fabricated through the well-known modified chemical vapor deposition (MCVD) process without going through the commonly used stage of post-ceramming. The main characteristics of the RE-doped oxyde nanoparticles namely, their density and mean diameter in the fibers are dictated by the concentration of alkaline earth element used as phase separating agent. Magnesium and erbium ...

  18. Experimental study of vapor local characteristics in upward low pressure boiling tube

    SUN Qi; ZHAO Hua; XI Zhao; YANG Rui-Chang

    2003-01-01

    Radial distribution of vapor local parameters, including local void fraction, interfacial velocity, bubblesize, bubble frequency and interfacial area concentration, are investigated through the measurement in an upwardboiling tube using dual-sensor optical probe. In addition, a new local parameter -"local bubble number concentra-tion" is developed on the basis of bubble frequency. The analysis shows that this parameter can reflect bubble numberdensity in space, and has clear physical meaning.

  19. Negotiating meaning through artefacts

    Tavella, Elena

    2015-01-01

    This research contributes to the domain of strategy making, specifically to unpacking the complexity of sociomateriality in strategy discourse. Scholars have emphasized the potential of artefacts to enhance sensemaking during strategizing. However there is a lack of insight into how artefacts...... and conversational aspects are linked at the micro‑level of discourse, also how artefacts and sensemaking shape one another. This research addresses this gap by empirically analyzing strategy discourse within a facilitated modelling workshop. Considering strategizing as a socially constructed activity, the author...... analyzes a workshop transcript to assess the extent to which stakeholders’ appropriation of artefacts supports them in engaging in negotiation of meaning with action implications. Moreover, how artefacts and negotiation of meaning shape one another is identified. The data suggest that appropriating...

  20. A scanning Raman lidar for observing the spatio-temporal distribution of water vapor

    Yabuki, Masanori; Matsuda, Makoto; Nakamura, Takuji; Hayashi, Taiichi; Tsuda, Toshitaka

    2016-12-01

    We have constructed a scanning Raman lidar to observe the cross-sectional distribution of the water vapor mixing ratio and aerosols near the Earth's surface, which are difficult to observe when a conventional Raman lidar system is used. The Raman lidar is designed for a nighttime operating system by employing a ultra-violet (UV) laser source and can measure the water vapor mixing ratio at an altitude up to 7 km using vertically pointing observations. The scanning mirror system consists of reflective flat mirrors and a rotational stage. By using a program-controlled rotational stage, a vertical scan can be operated with a speed of 1.5°/s. The beam was pointed at 33 angles over range of 0-48° for the elevation angle with a constant step width of 1.5°. The range-height cross sections of the water vapor and aerosol within a 400 m range can be obtained for 25 min. The lidar signals at each direction were individually smoothed with the moving average to spread proportionally with the distance from the laser-emitting point. The averaged range at a distance of 200 m (400 m) from the lidar was 30.0 m (67.5 m) along the lidar signal in a specific direction. The experimental observations using the scanning lidar were conducted at night in the Shigaraki MU radar observatory located on a plateau with undulating topography and surrounded by forests. The root mean square error (RMSE) between the temporal variations of the water vapor mixing ratio by the scanning Raman lidar and by an in-situ weather sensor equipped with a tethered balloon was 0.17 g/kg at an altitude of 100 m. In cross-sectional measurements taken at altitudes and horizontal distances up to 400 m from the observatory, we found that the water vapor mixing ratio above and within the surface layer varied vertically and horizontally. The spatio-temporal variability of water vapor near the surface seemed to be sensitive to topographic variations as well as the wind field and the temperature gradient over the site

  1. Weighted Mean Impact Analysis

    Burger, Svenja

    2015-01-01

    Linear regression is a popular tool that is often applied to biometric and epidemiological data. It relies on strong model assumptions that are rarely satisfied. To overcome this difficulty, Brannath and Scharpenberg (2014) proposed a new population based interpretation of linear regression coefficients. The idea is to quantify how much the unconditional mean of the dependent variable Y can be changed by changing the distribution of the independent variable X. The maximum change is called "me...

  2. Feeling, Meaning, and Intentionality

    Bundgaard, Peer

    2014-01-01

    This article addresses the phenomenology of aesthetic experience. It first, critically, considers one of the most influential approaches to the psychophysics of aesthetic perception, viz. neuroaesthetics. Hereafter, it outlines constitutive tenets of aesthetic perception in terms of a particular...... relative to its object and the tools for meaning-making specific to that object, and not relative to the feeling (of beauty) it may elicit. Finally, I sketch the import this fact may have on a research program in empirical aesthetics....

  3. Urinary Tract Infection Caused by Citrobacter koseri in a Patient With Spina Bifida, an Ileal Conduit and Renal Caluli Progressing to Peri-nephric Abscess and Empyema.

    Stewart, Zachary E; Shaker, Mohammed; Baxter, J David

    2017-02-01

    Urological problems are common in spina bifida and are often treated with urinary diversions. Spina bifida and ileal conduits put patients at increased risk for ascending urinary tract infections. Here we present a novel case of a Citrobacter koseri urinary tract infection complicated by a perinephric abscess with pleural extension. To our knowledge, no case of an ascending C. koseri UTI progressing to peri-nephric abscess and empyema by direct extension exists in the literature.

  4. Enhancement of Median Nerve Regeneration by Mesenchymal Stem Cells Engraftment in an Absorbable Conduit: Improvement of Peripheral Nerve Morphology with Enlargement of Somatosensory Cortical Representation.

    Julia Teixeira Oliveira

    2014-10-01

    Full Text Available We studied the morphology and the cortical representation of the median nerve (MN, 10 weeks after a transection immediately followed by treatment with tubulization using a polycaprolactone (PCL conduit with or without bone marrow-derived mesenchymal stem cell (MSC transplant. In order to characterize the cutaneous representation of MN inputs in primary somatosensory cortex (S1, electrophysiological cortical mapping of the somatosensory representation of the forepaw and adjacent body parts was performed after acute lesion of all brachial plexus nerves, except for the MN. This was performed in ten adult male Wistar rats randomly assigned in 3 groups: MN Intact (n=4, PCL-Only (n=3 and PCL+MSC (n=3. Ten weeks before mapping procedures in animals from PCL-Only and PCL+MSC groups, animal were subjected to MN transection with removal of a 4-mm-long segment, immediately followed by suturing a PCL conduit to the nerve stumps with (PCL+MSC group or without (PCL-Only group injection of MSC into the conduit. After mapping the representation of the MN in S1, animals had a segment of the regenerated nerve processed for light and transmission electron microscopy. For histomorphometric analysis of the nerve segment, sample size was increased to 5 animals per experimental group. The PCL+MSC group presented a higher number of myelinated fibers and a larger cortical representation of MN inputs in S1 (3,383±390 fibers; 2.3 mm2, respectively than the PCL-Only group (2,226±575 fibers; 1.6 mm2. In conclusion, MSC-based therapy associated with PCL conduits can improve MN regeneration. This treatment seems to rescue the nerve representation in S1, thus minimizing the stabilization of new representations of adjacent body parts in regions previously responsive to the MN.

  5. Véhicule connecté, véhicule à délégation de conduite. Aspects juridiques. Cours pour Renault, Guyancourt, septembre 2016.

    Guilbot, Michèle

    2016-01-01

    Présentation générale des principaux aspects juridiques du véhicule connecté et du véhicule à délégation de conduite (ou véhicule 'autonome') : contexte et risques potentiels, obligations de sécurité et droit, protection des données à caractère personnel et de la vie privée

  6. Inverse Dipolar Magnetic Anomaly Over the Volcanic Cone Linked to Reverse Polarity Magnetizations in Lavas and Tuffs - Implications for the Conduit System

    Fucugauchi, J. U.; Perez-Cruz, L. L.; Trigo-Huesca, A.

    2012-12-01

    A combined magnetics and paleomagnetic study of Toluquilla monogenetic volcano and associated lavas and tuffs from Valsequillo basin in Central Mexico provides evidence on a magnetic link between lavas, ash tuffs and the underground volcanic conduit system. Paleomagnetic analyses show that lavas and ash tuffs carry reverse polarity magnetizations, which correlate with the inversely polarized dipolar magnetic anomaly over the volcano. The magnetizations in the lava and tuff show similar southward declinations and upward inclinations, supporting petrological inferences that the tuff was emplaced while still hot and indicating a temporal correlation for lava and tuff emplacement. Conduit geometry is one of the important controlling factors in eruptive dynamics of basaltic volcanoes. However volcanic conduits are often not, or only partly, exposed. Modeling of the dipolar anomaly gives a reverse polarity source magnetization associated with a vertical prismatic body with southward declination and upward inclination, which correlates with the reverse polarity magnetizations in the lava and tuff. The study documents a direct correlation of the paleomagnetic records with the underground magmatic conduit system of the monogenetic volcano. Time scale for cooling of the volcanic plumbing system involves a longer period than the one for the tuff and lava, suggesting that magnetization for the source of dipolar anomaly may represent a long time average as compared to the spot readings in the lava and tuff. The reverse polarity magnetizations in lava and tuff and in the underground source body for the magnetic anomaly are interpreted in terms of eruptive activity of Toluquilla volcano at about 1.3 Ma during the Matuyama reverse polarity C1r.2r chron.

  7. Meaning and significance of

    Ph D Student Roman Mihaela

    2011-05-01

    Full Text Available The concept of "public accountability" is a challenge for political science as a new concept in this area in full debate and developement ,both in theory and practice. This paper is a theoretical approach of displaying some definitions, relevant meanings and significance odf the concept in political science. The importance of this concept is that although originally it was used as a tool to improve effectiveness and eficiency of public governance, it has gradually become a purpose it itself. "Accountability" has become an image of good governance first in the United States of America then in the European Union.Nevertheless,the concept is vaguely defined and provides ambiguous images of good governance.This paper begins with the presentation of some general meanings of the concept as they emerge from specialized dictionaries and ancyclopaedies and continues with the meanings developed in political science. The concept of "public accontability" is rooted in economics and management literature,becoming increasingly relevant in today's political science both in theory and discourse as well as in practice in formulating and evaluating public policies. A first conclusin that emerges from, the analysis of the evolution of this term is that it requires a conceptual clarification in political science. A clear definition will then enable an appropriate model of proving the system of public accountability in formulating and assessing public policies, in order to implement a system of assessment and monitoring thereof.

  8. Extension of in-situ stress test analysis to rapid hole evacuation at Yucca Mountain due to a network of open conduits

    Davies, J.B.

    1994-01-01

    Yucca Mountain is underlain by tuffaceous rocks that are highly fractured and jointed. During drilling of bore-holes at Yucca Mountain there were numerous occurrences of lost circulation when whole mud was taken by the formation. This evidence suggests that parts of Yucca Mountain are controlled hydrologicaly by a network of open conduits along the existing joints and fractures. Also at Yucca Mountain, stress tests have been performed in-situ by charging a small section along the boreholes with an excess pressure head of water. For many of these tests, the initial drop in water head was so rapid that within seconds up to hundreds of meters of fall had occurred. The opening of fractures as the excess head increases has previously been proposed as an important factor in explaining the shape of the stress test curves at lower pressures. We propose that such induced hydraulic fractures, under increasing water heads, can grow to a length sufficient to intersect the existing network of open joints and fractures. We extend our previous model to incorporate flow out along these open conduits and examine the initial rapid drop in terms of these extended models. We show that this rapid evacuation model fits the observed data from many slug tests in wells in the vicinity of Yucca Mountain. This result is confirmation of the drilling evidence that a network of open conduits exists at various depths below the water table and over a large geographic region around Yucca Mountain.

  9. Analysis of Drainage Capacity of Urban Conduits Based on SWMM%基于SWMM的城市雨水管网排水能力分析

    王祥; 张行南; 张文婷; 张涛

    2011-01-01

    Actual drainage capacity of urban conduits plays a very important role in urban drainage and flood control. In order to analyse the actual drainage capacity, the drainage capacities of study area in different design rainstorm return periods(P=0.25a, 0.5a, 1a,2a, 5a, 10a) are analysed by the storm water management model(SWMM). Conduits that are filled for longer time and change greatly are found out under 6 design rainstorms. The results provide a basis for reconstruction of urban conduits.%城市雨水管网实际排水能力对城市排涝和防洪起着重要作用.为了分析管网实际排水能力,采用暴雨管理模型(SWMM)对研究区域在设计暴雨重现期P=0.25 a、0.5 a、1 a、2 a、5 a、10 a情形下的排水能力进行分析.在6种设计暴雨情形下,得出了满流时间较长和变化较大的管道,为实际的城市雨水管网改造提供依据.

  10. Distilling allometric and environmental information from time series of conduit size: the standardization issue and its relationship to tree hydraulic architecture.

    Carrer, Marco; von Arx, Georg; Castagneri, Daniele; Petit, Giai

    2015-01-01

    Trees are among the best natural archives of past environmental information. Xylem anatomy preserves information related to tree allometry and ecophysiological performance, which is not available from the more customary ring-width or wood-density proxy parameters. Recent technological advances make tree-ring anatomy very attractive because time frames of many centuries can now be covered. This calls for the proper treatment of time series of xylem anatomical attributes. In this article, we synthesize current knowledge on the biophysical and physiological mechanisms influencing the short- to long-term variation in the most widely used wood-anatomical feature, namely conduit size. We also clarify the strong mechanistic link between conduit-lumen size, tree hydraulic architecture and height growth. Among the key consequences of these biophysical constraints is the pervasive, increasing trend of conduit size during ontogeny. Such knowledge is required to process time series of anatomical parameters correctly in order to obtain the information of interest. An appropriate standardization procedure is fundamental when analysing long tree-ring-related chronologies. When dealing with wood-anatomical parameters, this is even more critical. Only an interdisciplinary approach involving ecophysiology, wood anatomy and dendrochronology will help to distill the valuable information about tree height growth and past environmental variability correctly.

  11. Large-area irradiated low-level laser effect in a biodegradable nerve guide conduit on neural regeneration of peripheral nerve injury in rats.

    Shen, Chiung-Chyi; Yang, Yi-Chin; Liu, Bai-Shuan

    2011-08-01

    This study used a biodegradable composite containing genipin-cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles (genipin-gelatin-tricalcium phosphate, GGT), developed in a previous study, as a nerve guide conduit. The aim of this study was to analyse the influence of a large-area irradiated aluminium-gallium-indium phosphide (AlGaInP) diode laser (660 nm) on the neural regeneration of the transected sciatic nerve after bridging the GGT nerve guide conduit in rats. The animals were divided into two groups: group 1 comprised sham-irradiated controls and group 2 rats underwent low-level laser (LLL) therapy. A compact multi-cluster laser system with 20 AlGaInP laser diodes (output power, 50mW) was applied transcutaneously to the injured peripheral nerve immediately after closing the wound, which was repeated daily for 5 min for 21 consecutive days. Eight weeks after implantation, walking track analysis showed a significantly higher sciatic function index (SFI) score (Pregenerated nerve tissue in the laser-treated group were superior to those of the sham-irradiated group. Thus, the motor functional, electrophysiologic and histomorphometric assessments demonstrate that LLL therapy can accelerate neural repair of the corresponding transected peripheral nerve after bridging the GGT nerve guide conduit in rats.

  12. Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

    Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

    2013-12-01

    An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

  13. The Recent Interdecadal and Interannual Variation of Water Vapor Transport over Eastern China

    SUN Bo; ZHU Yali; WANG Huijun

    2011-01-01

    The climatological characteristics and interdecadal variability of the water vapor transport and budget over the Yellow River-Huaihe River valleys (YH1) and the Yangtze River-Huaihe River valleys (YH2) of East China were investigated in this study,using the NCEP/NCAR monthly mean reanalysis datasets from 1979 to 2009.Changes in the water vapor transport pattern occurred during the late 1990s over YH1 (YH2) that corresponded with the recent interdecadal changes in the eastern China summer precipitation pattern.The net moisture influx in the YH1 increased and the net moisture influx in the YH2 decreased during 2000-2009 in comparison to 1979-1999.Detailed features in the moisture flux and transport changes across the four boundaries were explored.The altered water vapor transport over the two domains can be principally attributed to the additive effects of the changes in the confluent southwesterly moisture flow by the Indian summer monsoon and East Asian summer monsoon (related with the eastward recession of the western Pacific subtropical high).The altered water vapor transport over YH1 was also partly caused by the weakened midlatitude westerlies.

  14. An Analytical Formula for Potential Water Vapor in an Atmosphere of Constant Lapse Rate

    Ali Varmaghani

    2012-01-01

    Full Text Available Accurate calculation of precipitable water vapor (PWV in the atmosphere has always been a matter of importance for meteorologists. Potential water vapor (POWV or maximum precipitable water vapor can be an appropriate base for estimation of probable maximum precipitation (PMP in an area, leading to probable maximum flood (PMF and flash flood management systems. PWV and POWV have miscellaneously been estimated by means of either discrete solutions such as tables, diagrams or empirical methods; however, there is no analytical formula for POWV even in a particular atmospherical condition. In this article, fundamental governing equations required for analytical calculation of POWV are first introduced. Then, it will be shown that this POWV calculation relies on a Riemann integral solution over a range of altitude whose integrand is merely a function of altitude. The solution of the integral gives rise to a series function which is bypassed by approximation of saturation vapor pressure in the range of -55 to 55 degrees Celsius, and an analytical formula for POWV in an atmosphere of constant lapse rate is proposed. In order to evaluate the accuracy of the suggested equation, exact calculations of saturated adiabatic lapse rate (SALR at different surface temperatures were performed. The formula was compared with both the diagrams from the US Weather Bureau and SALR. The results demonstrated unquestionable capability of analytical solutions and also equivalent functions.

  15. Experimental Measurements and Correlations Isobaric Vapor-Liquid Equilibria for Water + Acetic Acid + Sec-butyl Acetate at 101.3 kPa

    LI Ling; HE Yong; WU Yanxiang; ZOU Wenhu

    2013-01-01

    Isobaric vapor-liquid equilibrium(VLE) data for acetic acid + sec-butyl acetate and water + acetic acid + sec-butyl acetate systems were determined at 101.3 kPa using a modified Rose type.The nonideality of the vapor phase caused by the association of the acetic acid was corrected by the chemical theory and Hayden-O'Connell method.Thermodynamic consistency was tested for the binary VLE data.The experimental data were correlated successfully with the Non-Random Two Liquids (NRTL) model.The Root Mean Square Deviation (RMSD) of the ternary system was 0.0038.The saturation vapor pressure of sec-butyl acetate at 329 to 385 K was measured by means of two connected equilibrium cells.The vapor pressures of water and sec-butyl acetate were correlated with the Antoine equation.The binary interaction parameters and the ternary VLE data were obtained from this work.

  16. Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling

    S. Sugiharto

    2014-08-01

    Full Text Available Measurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10” outside diameter and contains dry vapor at a pressure of 8 kg/cm2 and a temperature of 170 oC. Krypton-85 gas isotope (85Kr has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m2/s, calculated from the axial dispersion model.

  17. Kinetics of small particle activation in supersaturated vapors

    McGraw, R.; Wang, J.

    2010-08-29

    We examine the nucleated (with barrier) activation of perfectly wetting (zero contact angle) particles ranging from bulk size down to one nanometer. Thermodynamic properties of the particles, coated with liquid layers of varying thickness and surrounded by vapor, are analyzed. Nano-size particles are predicted to activate at relative humidity below the Kelvin curve on crossing a nucleation barrier, located at a critical liquid layer thickness such that the total particle size (core + liquid layer) equals the Kelvin radius (Fig. 1). This barrier vanishes precisely as the critical layer thickness approaches the thin layer limit and the Kelvin radius equals the radius of the particle itself. These considerations are similar to those included in Fletcher's theory (Fletcher, 1958) however the present analysis differs in several important respects. Firstly, where Fletcher used the classical prefactor-exponent form for the nucleation rate, requiring separate estimation of the kinetic prefactor, we solve a diffusion-drift equation that is equivalent to including the full Becker-Doering (BD) multi-state kinetics of condensation/evaporation along the growth coordinate. We also determine the mean first passage time (MFPT) for barrier crossing (Wedekind et al., 2007), which is shown to provide a generalization of BD nucleation kinetics especially useful for barrier heights that are considerably lower than those typically encountered in homogeneous vapor-liquid nucleation, and make explicit comparisons between the MFPT and BD kinetic models. Barrier heights for heterogeneous nucleation are computed by a thermo-dynamic area construction introduced recently to model deliquescence and efflorescence of small particles (McGraw and Lewis, 2009). In addition to providing a graphical representation of the activation process that offers new insights, the area construction provides a molecular approach that avoids explicit use of the interfacial tension. Typical barrier profiles for

  18. Vapor Online Monitor Model of Vapor Power Station Based on UML

    2001-01-01

    We presents a vapor online monitor system model of vapor power station developed by visual tool rational rose2000. Use cases such as on line instrument (onlineinstr), control, query, report, real database (realdb) and alarm are generated according to the system requirements. Use case view and class view of the system are formed at the same time. As for all the UML models of the system, this paper focuses the discussion on the class view, the component diagram of the control class and the sequence diagram of the query class. Corresponding C++ codes are produced and finally transferred into the spot running software.

  19. Dynamic headspace generation and quantitation of triacetone triperoxide vapor.

    Giordano, Braden C; Lubrano, Adam L; Field, Christopher R; Collins, Greg E

    2014-02-28

    Two methods for quantitation of triacetone triperoxide (TATP) vapor using a programmable temperature vaporization (PTV) inlet coupled to a gas chromatography/mass spectrometer (GC/MS) have been demonstrated. The dynamic headspace of bulk TATP was mixed with clean humid air to produce a TATP vapor stream. Sampling via a heated transfer line to a PTV inlet with a Tenax-TA™ filled liner allowed for direct injection of the vapor stream to a GC/MS for vapor quantitation. TATP was extracted from the vapor stream and subsequently desorbed from the PTV liner for splitless injection on the GC column. Calibration curves were prepared using solution standards with a standard split/splitless GC inlet for quantitation of the TATP vapor. Alternatively, vapor was sampled onto a Tenax-TA™ sample tube and placed into a thermal desorption system. In this instance, vapor was desorbed from the tube and subsequently trapped on a liquid nitrogen cooled PTV inlet. Calibration curves for this method were prepared from direct liquid injection of standards onto samples tube with the caveat that a vacuum is applied to the tube during deposition to ensure that the volatile TATP penetrates into the tube. Vapor concentration measurements, as determined by either GC/MS analysis or mass gravimetry of the bulk TATP, were statistically indistinguishable. Different approaches to broaden the TATP vapor dynamic range, including diluent air flow, sample chamber temperature, sample vial orifice size, and sample size are discussed. Vapor concentrations between 50 and 5400ngL(-1) are reported, with stable vapor generation observed for as long as 60 consecutive hours.

  20. Application de la systémique à la conception d'un modèle de conduite en mode dégradé d'une centrale nucléaire

    Millerat, Pierre; Chaillot, Mathias; Ermine, Jean-Louis

    1996-01-01

    International audience; Cette publication présente un modèle de conduite d'une centrale nucléaire en mode dégradé fondé sur l'élaboration conjointe de trois modèles. Le premier décrit l'ensemble des phénomènes physiques pertinents pour le pilotage d'une centrale nucléaire, le second l'ensemble des activités de conduite d'un opérateur, le troisième une procédure de conduite en mode dégradé d'une centrale nucléaire. La finalité de ce modèle est d'expliquer à un opérateur cette conduite....