WorldWideScience

Sample records for vapor conduit means

  1. GOZCARDS Merged Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpH2O) contains zonal means and related...

  2. GOZCARDS Source Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  3. Liquid–vapor asymmetry in mean-field theories of simple, polar and ionic fluids

    International Nuclear Information System (INIS)

    Based on the concept of complete scaling, Wang and Anisimov have recently presented an approach that allows one to separate and quantify different contributions to the liquid–vapor asymmetry of fluids. In particular, they proposed a way of estimating the two contributions to the asymptotic slope of the diameter of the coexistence curve near the critical point, D, from mean-field theories. We have analyzed several mean-field theories describing the liquid–vapor equilibrium of simple, polar and ionic model fluids, namely, the restricted primitive model of ionic fluids, a fluid composed of dipolar hard spheres, the Yukawa fluid and the square-well fluid. The latter two allow for a systematic study of the influence of the interaction range on both the absolute magnitude of the slope of the diameter and of the relative contribution that each source of liquid–vapor asymmetry makes. In addition, the strength of the Yang–Yang ratio R-barH for each model fluid is estimated. We present results for a number of different theories for each fluid and discuss the observed trends. For simple fluids, D and R-bar H become larger with increasing range of the interactions. The theories for the ionic fluid predict values of D and of R-bar H that are larger than those for simple fluids, indicating a system that is governed by long-range interactions. The dipolar fluid seems to be intermediate between simple and ionic fluids in these respects; withinc fluids in these respects; within the Onsager theory, however, an exceptional behavior of the two contributions to D is found in the sense that they reinforce each other instead of yielding the partial cancellation observed for other fluids

  4. Rosseland mean opacities of air and H-chondrite vapor in meteor entry problems

    International Nuclear Information System (INIS)

    The Rosseland mean absorption coefficients are determined for air and the vapor of the H-chondrites for use in calculating the ablation behavior of asteroidal meteoroids. For air, the calculated is made for temperatures between 8000 K and 35,000 K, and for H-chondrites from 3000 K to 20,000 K. Density values of 0.01, 0.1, 1., and 10 kg/m3 are considered. For H-chondrite, O, Si, Mg, Fe, S, O+, Si+, Mg+, S+, O2, SiO, MgO, FeO, and SO are considered as radiators. The latest available data on intensity parameters are used. To ensure accuracy, line profiles are calculated far into the wings. Bound-free absorption by the states of principal quantum numbers equal to or larger than four are accounted for assuming the associated Gaunt factors to be unity. The calculated Rosseland mean absorption coefficient values are substantially larger than the published values, especially at low temperatures. -- Highlights: •Rosseland mean absorption coefficients of air and H-chondrite are given. •Radiation mechanisms previously not considered are accounted for. •Temperature and pressure ranges are those expected in entry flights of meteors. •The calculated coefficient values are larger than the existing values

  5. Transverse colon conduit diversion

    International Nuclear Information System (INIS)

    The versatility and other advantages of the transverse colon conduit for urinary diversion have been described and implemented in 50 patients. Because most patients considered for this procedure will be at high risk because of a history of significant pelvic irradiation, underlying malignancy, poor renal function, fistula, and so forth, the technical details of surgery and patient selection cannot be minimized. The transverse colon segment is indicated for primary supravesical diversion as well as for salvage of problems related to ileal conduits. Adenocarcinoma of the colon is an unlikely long-term complication of this form of diversion because the fecal stream is absent. Now that the transverse colon conduit has been used for more than 10 years, meaningful comparisons with ileal segments should soon be available

  6. Seal between metal and ceramic conduits

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, Richard Paul; Tentarelli, Stephen Clyde

    2015-02-03

    A seal between a ceramic conduit and a metal conduit of an ion transport membrane device consisting of a sealing surface of ceramic conduit, a sealing surface of ceramic conduit, a single gasket body, and a single compliant interlayer.

  7. Conduit Coating Abrasion Testing

    Science.gov (United States)

    Sullivan, Mary K.

    2013-01-01

    During my summer internship at NASA I have been working alongside the team members of the RESTORE project. Engineers working on the RESTORE project are creating ·a device that can go into space and service satellites that no longer work due to gas shortage or other technical difficulties. In order to complete the task of refueling the satellite a hose needs to be used and covered with a material that can withstand effects of space. The conduit coating abrasion test will help the researchers figure out what type of thermal coating to use on the hose that will be refueling the satellites. The objective of the project is to determine whether or not the conduit coating will withstand the effects of space. For the RESTORE project I will help with various aspects of the testing that needed to be done in order to determine which type of conduit should be used for refueling the satellite. During my time on the project I will be assisting with wiring a relay board that connected to the test set up by soldering, configuring wires and testing for continuity. Prior to the testing I will work on creating the testing site and help write the procedure for the test. The testing will take place over a span of two weeks and lead to an informative conclusion. Working alongside various RESTORE team members I will assist with the project's documentation and records. All in all, throughout my internship at NASA I hope to learn a number of valuable skills and be a part of a hard working team of engineers.

  8. Vapor liquid fraction determination

    International Nuclear Information System (INIS)

    This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)

  9. Urodynamic evaluation of ileal conduit function.

    Science.gov (United States)

    Knapp, P M; Konnak, J W; McGuire, E J; Savastano, J A

    1987-05-01

    Bilateral hydroureteronephrosis following ileal conduit urinary diversion is not uncommon. It may be owing to ureteroileal stenosis, stomal stenosis or a poorly compliant ileal conduit. The standard evaluation of stoma size, conduit residual urine and a loopogram often fail to allow determination of the cause of ureteral dilatation. In addition to these standard tests, we have used conduit urodynamics to study conduit function with a triple lumen urodynamic catheter to measure simultaneously conduit pressure proximal and distal to the fascia during filling under fluoroscopy. In 4 control patients with normal upper tracts who were studied with this technique conduit leak point pressures ranged from 5 to 20 cm. water pressure. Six patients with bilateral hydroureteronephrosis were studied to evaluate conduit function. We found abnormalities in 5 patients, including functional stomal stenosis in 2, an atonic loop in 1, segmental obstruction in 1 and a high pressure noncompliant distal segment in 1. PMID:3573186

  10. 76 FR 76895 - Conduit Financing Arrangements

    Science.gov (United States)

    2011-12-09

    ...DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR...1545-BH77 Conduit Financing Arrangements AGENCY: Internal Revenue Service (IRS...section 7701(l) of the Internal Revenue Code (the conduit financing regulations)....

  11. 77 FR 22480 - Conduit Financing Arrangements; Correction

    Science.gov (United States)

    2012-04-16

    ...DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Part...RIN 1545-BH77 Conduit Financing Arrangements; Correction AGENCY: Internal Revenue Service (IRS...providing guidance on conduit financing arrangements. The...

  12. The corrosion effect on the conduit systems

    International Nuclear Information System (INIS)

    The conduits in the buildings require a regular and permanent control, in order to avoid the risks of deterioration caused by the corrosion or the escape of water. In this work, we present a thermal nondestructive testing method of concrete structures containing water conduits, based on numerical modeling in three dimensions. The goal is to study the detectability of these conduits in different situations and to give a thermal characterization of the rust behaviour in the steel conduits. (author)

  13. Measurements of equilibrium water vapor pressures for the dehydration of magnesium, manganese and cobalt formate dihydrates by means of the transpiration method.

    Science.gov (United States)

    Masuda, Y; Hatakeyama, M

    1996-10-01

    The equilibrium water vapor pressures for the thermal dehydration of Mg(HCO(2))(2). 2H(2)O, Mn(HCO(2))(2). 2H(2)O and Co(HCO(2))(2). 2H(2)O were measured by means of the transpiration method. These hydrates form isomorphous crystals with space group P21/c. In this structure, the water molecules lie in the planes parallel to the (100) planes. Thermodynamic data such as DeltaG, DeltaH and DeltaS were derived from the values of the water vapor pressures. The relationship between these thermodynamic data and the crystal structures is discussed. PMID:18966655

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

    Directory of Open Access Journals (Sweden)

    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 similar site-specific Tm-based model for the near equatorial station, Bangalore. A simple site-specific linear relation without accounting for the temperature effect through Tm is also found to be quite adequate for Bangalore. But for Hyderabad, a station located at slightly higher latitude, the deviation for the linear model is found to be larger than that of the Tm-based model. This indicates that even though a simple linear regression model is quite adequate for the near equatorial stations, where the temperature variations are relatively small, for estimating PW from GPS data at higher latitudes this model is inferior to the Tm-based model.

  15. Peripheral nerve conduits: technology update

    Directory of Open Access Journals (Sweden)

    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

  16. Cryovolcanic Conduit Evolution and Eruption on Icy Satellites

    Science.gov (United States)

    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 cryovolcanic plumes are confirmed on Europa. However, eruption from an ocean is more challenging there, as far greater volatile contents would be required to facilitate mass continuity from an initial fracture, and hence eruption, from the higher pressure source. Shallower sources, such as proposed under chaos, are less challenging.

  17. Extra cardiac conduit Fontan procedure in 41 patients

    Directory of Open Access Journals (Sweden)

    Safarpour Gh

    2007-07-01

    Full Text Available Background: The Fontan operation is the definitive operation for palliation of complex congenital heart disease with single –ventricle physiology. The use of the extra cardiac conduit has recently been gaining popularity. The purpose of this study was to compare the outcomes of extra cardiac conduit Fontan procedure (off-pump technique and that of traditional technique (lateral tunnel technique in which cardiopulmonary bypass is routinely used. Methods: Forty one patients in different age groups underwent extra cardiac conduit Fontan procedure between April 2001 and December 2004. Data were collected from ICU sheets, files and during follow up visits. Under general anesthesia and through median sternotomy, using two temporary decompressing shunts, superior vena cava implanted on right pulmonary artery and a conduit interposed between transected inferior vena cava and main pulmonary artery. Fenestration was done in almost all patients and previous shunts were closed if there were any. Results: Of our patients, 13 were female and 28 were male. Mean age of the patients was 11.1 years (SD=7.8.In 24.4% of cases Fontan procedure was done as the first palliative surgery and in 75.6% of them there was previous history of palliative procedures. In 6 patients (14.6% we were constrained to use cardiopulmonary bypass which was predictable or necessary in 50% of cases. There was no reoperation due to post operative bleeding. Two cases suffered from prolonged plural effusion. Our in-hospital mortality was 9.8%. During 2-24 months follow up, we found two cases who were in NYHA functional class II and one case in functional class I. Conclusion: Extra cardiac conduit Fontan procedure could be used in a safe way. The results of this study were comparable and even in some cases better than that of the traditional technique.

  18. Imparting super hydro/oleophobic properties to cotton fabric by means of molecular and nanoparticles vapor deposition methods

    International Nuclear Information System (INIS)

    Super hydro/oleophobic cotton fabrics were prepared using nanoparticle vapor deposition and molecular vapor deposition techniques. The surface was roughened by trimethylaluminum/water nanoparticles followed by functionalization with (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane. This process imparted unique hydro/oleophobic properties (contact angle >160°). In contrast to wet chemistry processes, the chemicals used and the thickness of the coatings produced by this method could be controlled precisely, which allowed for the minimization of waste generation while preserving the original properties of the fabric. Dynamic contact angles were measured and the fabrics that were coated using this technique showed low-contact-angle hysteresis properties. Scanning electron microscopy and universal attenuated total reflectance Fourier transform infrared spectroscopy confirmed the formation of a nanostructure-roughened surface. Drop dynamics such as the force of droplet movement, work of adhesion, and surface free energy were also calculated.

  19. Chemical heat pump: a simple means to conserve energy. Final report, September 1, 1976-February 28, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, L.

    1977-01-01

    This is the final report of a six-month preliminary investigation into the applicability of the Chemical Heat Pump (CHP) for day-and-night, heating-and-cooling of residences with solar energy. The CHP consists of two containers and a joining conduit. Its working mechanism is the reversible absorption of water vapor onto a dessicant such as powdered magnesium chloride dihydrate in one container, the reversible evaporation of water in the other container, and the reversible passage of water vapor through the conduit. These vapor processes occur as consequences of differing temperatures imposed on the two containers. Thus, heating the absorber container with solar energy increases vapor pressure of the enclosed material and results in its dehydration, while simultaneously cooling the water container with ambient air, lowers vapor pressure and results in vapor condensation to liquid. When the absorber is no longer heated by the sun, the water will evaporate from the water container at ambient temperature and its vapors will condense onto the dessicant at a higher temperature with release of the heat of hydration. This energy, is used for heating the house. Additionally, evaporation of water from within the water container provides means for residential cooling in warm weather. Analytical and experimental procedures and results are detailed. (WHK)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  1. Conduit network structural controls on groundwater flow and solute breakthrough in karst aquifers

    Science.gov (United States)

    Ronayne, M. J.

    2014-12-01

    The structure of the conduit network is a key factor that governs flow and transport behavior in karst aquifers. The network inlet (recharge) and outlet (karst spring) locations may be known, but direct measurements of the conduit network and associated structural properties (volume fraction, sinuosity) are generally limited for the aquifer interior. This study considers the information content of indirect solute tracer data for inferring structural properties of the network. Observations from selected karst aquifers in the USA provide motivation for a numerical investigation that utilizes synthetic models characterized by a branching conduit network surrounded by permeable matrix material, with focused discharge at a single karst spring. The permeable matrix allows for solute exchange between the conduits and diffuse flow domain. Results from physics-based flow and transport simulations demonstrate how variations in conduit network geometry influence solute breakthrough at the outlet. Solute particle arrival time distributions, generated from synthetic tracer tests, are described by the mean, variance, skewness, and early (5th percentile) breakthrough times. The results indicate a clear relationship between these statistical moments and structural properties of the network, highlighting the potential signature of conduit network structure on hydrologic response and solute transport in karst aquifers.

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

    Science.gov (United States)

    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.

  3. Control adaptativo para arranque de generadores de vapor mediante redes neuronales dinámicas / STEAM GENERATORS START-UP BY MEANS OF AN ADAPTIVE CONTROL AND DYNAMIC NEURAL NETWORKS

    Scientific Electronic Library Online (English)

    Miguel, Aguirre.

    2009-06-01

    Full Text Available En este documento se describe el modelado y el control adaptativo mediante redes neuronales auto-recurrentes para arranque de un generador de vapor, con el fin de disminuir el tiempo de arranque y minimizar las variaciones y fallas por ajuste manual de las variables involucradas en este proceso. La [...] variable de proceso a controlar para el arranque, es principalmente la temperatura, además se controla el oxigeno para garantizar la máxima eficiencia de la combustión en los quemadores. Ambas se controlan mediante la manipulación de la relación gas natural/aire de combustión. Los datos de entrenamiento son empíricos del proceso y son medidos cada 2 minutos. La simulación del proceso y del controlador se realizó en MATLAB. Las acciones de control resultantes concuerdan con un arranque normal del generador de vapor. Abstract in english In this document it will be explain the modeling and adaptive control by means of auto-recurrent neural networks for steam generators start-up with the purpose of obtain a minimum in the start-up time, the variance and the failures for manual settings of the process variables. The primary start-up p [...] rocess variable to control is the temperature, but in addition will be control the oxygen for guarantee the maximum performance of the burner combustion. Both variables were controlled setting the relation between the natural gas and combustion air. The training data are empiric of the process and it was sampled every 2 minutes. The process and controller simulation was realized in MATLAB. The controller actions obtained in the simulations had concordance with a normal start up of the steam generator.

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

    OpenAIRE

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

    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 of stem hydraulic conductivity. These mathematical descriptions can be used to model the xylem water transport system. Within a chrysanthemum stem of 1.0 m, the conduit half-length (the length with...

  5. MRI of the heart following implantation of a left ventricular apico-aortic conduit

    International Nuclear Information System (INIS)

    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. (origlume of 80 + 20.6 ml per heart beat. (orig.)

  6. Prediction of supercooled liquid vapor pressures and n-octanol/air partition coefficients for polybrominated diphenyl ethers by means of molecular descriptors from DFT method

    International Nuclear Information System (INIS)

    The molecular geometries of 209 polybrominated diphenyl ethers (PBDEs) were optimized at the B3LYP/6-31G* level with Gaussian 98 program. The calculated structural parameters were taken as theoretical descriptors to establish two novel QSPR models for predicting supercooled liquid vapor pressures (PL) and octanol/air partition coefficients (KOA) of PBDEs based on the theoretical linear solvation energy relationship (TLSER) model, respectively. The two models achieved in this work both contain three variables: most negative atomic partial charge in molecule (q-), dipole moment of the molecules (?) and mean molecular polarizability (?), of which R2 values are both as high as 0.997, their root-mean-square errors in modeling (RSMEE) are 0.069 and 0.062 respectively. In addition, the F-value of two models are both evidently larger than critical values F0.05 and the variation inflation factors (VIF) of variables herein are all less than 5.0, suggesting obvious statistic significance of the PL and KOA predicting models. The results of Leave-One-Out (LOO) cross-validation for training set and validation with external test set both show that the two models obtained exhibited optimum stability and good predictive power. We suggest that the QSPRs derived here can be used to predict accurately PL and KOA for non-tested PBDE congeners from Mono-BDEs to Hepta-BDEs and from Mono-BDEsno-BDEs to Hepta-BDEs and from Mono-BDEs to Hexa-BDEs, respectively

  7. Prediction of supercooled liquid vapor pressures and n-octanol/air partition coefficients for polybrominated diphenyl ethers by means of molecular descriptors from DFT method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zunyao [School of Biological and Chemical Engineering, Jiaxing University, Zhejiang Jiaxing, 314001 (China)], E-mail: wangzun315cn@163.com; Zeng Xiaolan [Department of Chemistry and Chemical Engineering, Xinyang Normal University, Henan Xinyang, 464000 (China); Zhai Zhicai [School of Biological and Chemical Engineering, Jiaxing University, Zhejiang Jiaxing, 314001 (China)

    2008-01-25

    The molecular geometries of 209 polybrominated diphenyl ethers (PBDEs) were optimized at the B3LYP/6-31G* level with Gaussian 98 program. The calculated structural parameters were taken as theoretical descriptors to establish two novel QSPR models for predicting supercooled liquid vapor pressures (P{sub L}) and octanol/air partition coefficients (K{sub OA}) of PBDEs based on the theoretical linear solvation energy relationship (TLSER) model, respectively. The two models achieved in this work both contain three variables: most negative atomic partial charge in molecule (q{sup -}), dipole moment of the molecules ({mu}) and mean molecular polarizability ({alpha}), of which R{sup 2} values are both as high as 0.997, their root-mean-square errors in modeling (RSMEE) are 0.069 and 0.062 respectively. In addition, the F-value of two models are both evidently larger than critical values F{sub 0.05} and the variation inflation factors (VIF) of variables herein are all less than 5.0, suggesting obvious statistic significance of the P{sub L} and K{sub OA} predicting models. The results of Leave-One-Out (LOO) cross-validation for training set and validation with external test set both show that the two models obtained exhibited optimum stability and good predictive power. We suggest that the QSPRs derived here can be used to predict accurately P{sub L} and K{sub OA} for non-tested PBDE congeners from Mono-BDEs to Hepta-BDEs and from Mono-BDEs to Hexa-BDEs, respectively.

  8. Secure E-Link For Jostle Conduit

    OpenAIRE

    Meenu Sahni

    2011-01-01

    In this paper, we delineated secure e-link for jostle conduit. Also, we depicted nearness function to obtain error free original message , which is deliberately required for Internet communication. It is the model of a real-life secures e-link system for any organization. In this model a sender can send a secret message even to a unacquainted person in an anonymous way.

  9. Secure E-Link For Jostle Conduit

    Directory of Open Access Journals (Sweden)

    Meenu Sahni

    2011-01-01

    Full Text Available In this paper, we delineated secure e-link for jostle conduit. Also, we depicted nearness function to obtain error free original message , which is deliberately required for Internet communication. It is the model of a real-life secures e-link system for any organization. In this model a sender can send a secret message even to a unacquainted person in an anonymous way.

  10. Assessment of conduit artery vasomotion using photoplethysmography

    Science.gov (United States)

    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

    Directory of Open Access Journals (Sweden)

    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. Pressure drop measurements of prototype NET and CEA cable-in-conduit conductors (CICCs)

    International Nuclear Information System (INIS)

    The pressure drop of two prototype cable-in-conduit conductors (CICCs) were measured. The NET conductor is a conventional type CICC, while the CEA conductor has a central flow channel to reduce hydraulic impedance. The pressure drop measurements were conducted with helium at temperatures ranging from 2K to 4.7K, and pressure from the saturated vapor pressure to in excess of 3 bar. Computer image analysis was used to estimate the flow cross sectional area and wetted perimeter of the conductors. The data are expressed in terms of a classical friction factor, and compared with precious experimental results

  13. Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005

    Science.gov (United States)

    Shoemaker, W. Barclay; Kuniansky, Eve L.; Birk, Steffen; Bauer, Sebastian; Swain, Eric D.

    2007-01-01

    This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by modifying horizontal conductances assembled by the Block-Centered Flow (BCF), Layer-Property Flow (LPF), or Hydrogeologic-Unit Flow Packages (HUF) of MODFLOW-2005. For both conduit flow pipes (CFPM1) and preferential flow layers (CFPM2), critical Reynolds numbers are used to determine if flow is laminar or turbulent. Due to conservation of momentum, flow in a laminar state tends to remain laminar and flow in a turbulent state tends to remain turbulent. This delayed transition between laminar and turbulent flow is introduced in the CFP, which provides an additional benefit of facilitating convergence of the computer algorithm during iterations of transient simulations. Specifically, the user can specify a higher critical Reynolds number to determine when laminar flow within a pipe converts to turbulent flow, and a lower critical Reynolds number for determining when a pipe with turbulent flow switches to laminar flow. With CFPM1, the Hagen-Poiseuille equation is used for laminar flow conditions and the Darcy-Weisbach equation is applied to turbulent flow conditions. With CFPM2, turbulent flow is approximated by reducing the laminar hydraulic conductivity by a nonlinear function of the Reynolds number, once the critical head difference is exceeded. This adjustment approximates the reductions in mean velocity under turbulent ground-water flow conditions.

  14. Parastomal Hernia as a Risk Factor for Ileal Conduit Fistulae

    Directory of Open Access Journals (Sweden)

    Thomas A. A Skinner

    2011-07-01

    Full Text Available Purpose: To review potential risk factors for the development of ileal conduit fistulae. Methods: Two patients were identified who had a remote history of an ileal conduit and who formed a fistula from the conduit—one to the small bowel and one to the skin. Their presentation, management and outcomes are described. Results: Both patients had parastomal hernias as the likely cause of their fistula formation. Discussion: Parastomal herniation may contribute to fistula formation due to a strangulated ischemic pressure necrosis of the adjacent ileal conduit and/or bowel.

  15. Further Development, Support and Enhancement of CONDUIT

    Science.gov (United States)

    Veronica, Moldoveanu; Levine, William S.

    1999-01-01

    From the first airplanes steered by handles, wheels, and pedals to today's advanced aircraft, there has been a century of revolutionary inventions, all of them contributing to flight quality. The stability and controllability of aircraft as they appear to a pilot are called flying or handling qualities. Many years after the first airplanes flew, flying qualities were identified and ranked from desirable to unsatisfactory. Later on engineers developed design methods to satisfy these practical criteria. CONDUIT, which stands for Control Designer's Unified Interface, is a modern software package that provides a methodology for optimization of flight control systems in order to improve the flying qualities. CONDUIT is dependent on an the optimization engine called CONSOL-OPTCAD (C-O). C-O performs multicriterion parametric optimization. C-O was successfully tested on a variety of control problems. The optimization-based computational system, C-O, requires a particular control system description as a MATLAB file and possesses the ability to modify the vector of design parameters in an attempt to satisfy performance objectives and constraints specified by the designer, in a C-type file. After the first optimization attempts on the UH-60A control system, an early interface system, named GIFCORCODE (Graphical Interface for CONSOL-OPTCAD for Rotorcraft Controller Design) was created.

  16. Cardiac compression secondary to a massively dilated substernal colon conduit.

    Science.gov (United States)

    Khan, Babar A; Ionescu, Ruxandra C; Halal, Ahmed M; Kesler, Kenneth A

    2012-11-01

    With the growing success of surgical repairs of congenital defects previously incompatible with life, it is expected of these patients to live longer and experience the complications of these corrective procedures. Esophageal atresia is a congenital defect that occurs in 1 out of 4000 births and is oftentimes a surgical emergency in which colonic conduits are routinely used for esophageal reconstruction. Colonic conduit redundancy and dilatation are well-recognized late complications of colon conduit surgeries for esophageal reconstructions. We report a rare case of symptomatic cardiac compression secondary to a massively dilated substernal colon conduit occurring 44 years after the initial childhood surgery in 1964 with rapid reversal of hemodynamic compromise after conduit removal. PMID:23164009

  17. Ross operation using a bovine bioprosthetic valve with autologous pericardial conduit in the pulmonary position.

    OpenAIRE

    Urrea, M. S.; Herrera, V.; Rey, A.; Vargas, J.

    1993-01-01

    Between 1 February 1992 and 1 March 1993, we performed Ross's aortic replacement in 7 men and 4 women with rheumatic heart disease. The patients' ages ranged from 22 to 60 years (mean, 41 years). All 11 patients had aortic valve disease; 2 also had mitral valve disease. In all patients, the right ventricular outflow tract was reconstructed using an autologous pericardial conduit containing a bovine cardiac valve bioprosthesis manufactured at our institution. The 2 patients who had mitral valv...

  18. Spotlight on CERN : Le code de conduite

    CERN Multimedia

    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.

  19. The use of the ex vivo Chandler Loop Apparatus to assess the biocompatibility of modified polymeric blood conduits.

    Science.gov (United States)

    Slee, Joshua B; Alferiev, Ivan S; Levy, Robert J; Stachelek, Stanley J

    2014-01-01

    The foreign body reaction occurs when a synthetic surface is introduced to the body. It is characterized by adsorption of blood proteins and the subsequent attachment and activation of platelets, monocyte/macrophage adhesion, and inflammatory cell signaling events, leading to post-procedural complications. The Chandler Loop Apparatus is an experimental system that allows researchers to study the molecular and cellular interactions that occur when large volumes of blood are perfused over polymeric conduits. To that end, this apparatus has been used as an ex vivo model allowing the assessment of the anti-inflammatory properties of various polymer surface modifications. Our laboratory has shown that blood conduits, covalently modified via photoactivation chemistry with recombinant CD47, can confer biocompatibility to polymeric surfaces. Appending CD47 to polymeric surfaces could be an effective means to promote the efficacy of polymeric blood conduits. Herein is the methodology detailing the photoactivation chemistry used to append recombinant CD47 to clinically relevant polymeric blood conduits and the use of the Chandler Loop as an ex vivo experimental model to examine blood interactions with the CD47 modified and control conduits. PMID:25178087

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:25788923

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

    Directory of Open Access Journals (Sweden)

    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.

  2. An in vivo study of tricalcium phosphate and glutaraldehyde crosslinking gelatin conduits in peripheral nerve repair.

    Science.gov (United States)

    Chen, Ming-Hong; Chen, Pei-Ru; Chen, Mei-Hsiu; Hsieh, Sung-Tsang; Huang, Jing-Shan; Lin, Feng-Huei

    2006-04-01

    In order to modulate the mechanical properties of gelatin, we previously developed a biodegradable composite composed by tricalcium phosphate and glutaraldehyde crosslinking gelatin (GTG) feasible for surgical manipulation. In this study, we evaluated the in vivo applications of GTG conduit for peripheral nerve repair. The effect of sciatic nerve reconstruction was compared between resorbable permeable GTG conduits and durable impermeable silicone tubes. Traditional methods of assessing nerve recovery following peripheral nerve repair including histomorphometric and electrophysiologic features were conducted in our study. In addition, autotomy score and sciatic function index (SFI) in walking tract analysis were used as additional parameters for assessing the return of nerve function. Twenty-four weeks after sciatic nerve repair, the GTG conduits were harvested. Microscopically, regeneration of nerves was observed in the cross-section at the mid portion of all implanted GTG conduits. The cross-sectional area of regenerated nerve of the GTG group was significant larger than that of the silicone group. In the compound muscle action potentials (CMAP), the mean recovery index of CMAP amplitude was 0.24 +/- 0.02 for the silicone group, 0.41 +/- 0.07 for the GTG group. The mean SFI increased with time in the GTG group during the evaluation period until 24 weeks. Walking tract analysis showed a higher SFI score in the GTG group at both 12 and 24 weeks. The difference reached a significant level at 24 weeks. Thus, the histomorphometric, electrophysiologic, and functional assessments demonstrate that GTG can be a candidate for peripheral nerve repair. PMID:16211569

  3. Ileal-conduit following cystectomy, single-institution revision of indications and outcome

    International Nuclear Information System (INIS)

    Objective was to revise indications, case fatality ratio, and postoperative early and late complications of ileal conduit as a method of urinary diversion. This is a retrospective study in which 200 patients underwent an ileal conduit from August 1994 to December 2000 in Mansoura Urology and Nephrology Center, Mansoura, Egypt. Preoperative criteria of patient selection, preoperative findings and postoperative follow-up data were reviewed. In 200 patients aged 29-75 years, with a mean age of 55.84-/+ 8.91 years, the ileal conduit was chosen as a method of urinary diversion, due to one of the following patient or surgical factors; 50 (25%) cardiopulmonary co-morbidities, 27(13.5%) liver cirrhosis, 20 (10%) impaired renal function, 18 (9%) poorly controlled diabetes mellitus and 3 (1.5%) morbid obesity. Frozen section pathological examination showed carcinoma invasion of the urethra in 26 (13%) and prostate stroma in 16 (8%) male patients. Severe adhesions and difficulty cystectomy were encountered in 25 (12.5%) patients. Tumor was found at or close to the bladder neck in 13 (6.5%) female patients and 2 (1%) patients were found to have short mesentery. The mean follow up period was 90.02 -/+ 22.63 months. Fatality rate was 2%. Twenty-three (11.5%) patients had early complications, while 36 (23.7%) patients had late complications. Ileal conduit is still the best urinary diversion method in many patients who have bladder cancer with associated chronic medical disease or ceh associated chronic medical disease or certain surgical factors that render other urinary diversion methods more difficult carry more postoperative morbidity and mortality or both. (author)

  4. Investigation of SH and CS radicals formation dynamics inside the hot filament chemical vapor deposition environment by means of cavity ringdown spectroscopy

    Science.gov (United States)

    Buzaianu, Madalina Dora

    2008-10-01

    The addition of traces amounts of sulfur containing gasses, such as H 2S, during the hot filament chemical vapor deposition of diamond thin films involving methane and hydrogen as a carrier gas, proved to enhance the formation of the nano-structured diamond and cause significant changes in the film growth behavior. The sulfur-incorporated nanocrystalline diamond, showing interesting electronic and tribological properties, raised scientific inquires about the fundamental mechanisms occurring inside the HFCVD reactor during the diamond growth. A better insight into the gas-phase and heterogeneous underlying processes can generate new ides for the customizing and optimization of the diamond synthesis in the view of new prospects of valuable technological applications. The SH and CS radicals, thought to be among the important precursors in the gas-phase and heterogeneous chemistry, were studied by means of Cavity Ringdown Spectroscopy (CRDS), a powerful non-intrusive, self-calibrating spectroscopic diagnostic tool, employed to detect the A(0) ? X(0) transition near 323 and 259 nm for SH and CS, respectively, and the A(0) ? X(1) transition near 352 nm for the SH radical. CRDS is particularly suitable to detect SH and CS radicals due to its high sensitivity, discrimination and spatial resolution, as well as the ability to provide absolute values of species concentrations. The fitting of the measured CRD decay traces of the SH and CS radicals provided the corresponding ringdown times. The substantial changes in the ringdown times observed when the filament temperature was raised to 2700 +/- 50 K (from 4.04 +/- 0.04 to 0.260 +/- 0.003 mus for SH and from 4.12 +/- 0.05 to 3.04 +/- 0.03 mus for CS, respectively) are compatible with the presence of SH and CS radicals. A simulation of the rotationally resolved SH and CS spectra near UV, based on the analysis of the radicals' Doppler line width, led to an estimate of their effective rotational temperature. The values obtained are ˜ 1750 +/- 250 K and 1800 +/- 250 K for SH and CS, respectively, which are lower than the measured filament temperature (i.e. 2700 +/- 50 K) by 1000 K at 2 mm from the filament. The radicals' rotational temperatures were studied as a function of filament distance and found to linearly decrease as the distance from the filament increases, such that a drop of approximately 1200 K is observed between 2 mm and 10 mm distance from the filament. The estimated rotational, translational and vibrational (A(0) ? X(1) of the SH radical) temperatures were found in good agreement for both radicals. A convolution procedure of the SH S R1 (10.5) line and CS R(15) - R(22) line cluster, involving an analysis of the Doppler and Lorentzian broadening widths provided the absolute numerical value of the species concentration. The concentration of the SH radical (2.2 x 1012 cm-3 ) was found to be about two orders of magnitude below that of the initial H2S (2.8 x 1014 cm-3), but about two orders of magnitude higher than that of the CS radical (2.7 x 1010 cm-3), at 2 mm below the filament. The SH and CS radical concentration profiles in the HFCVD system were measured in the presence and absence of a substrate as a function of distance from the filament to the laser probing area. The SH concentration profile was found to decrease by two orders of magnitude as the distance from the filament to the laser probing area increases, while the CS concentration remains approximately constant. The radical concentration profiles were measured in the presence and absence of a substrate as a function and CH4 and H2S input gas concentration. The concentration of SH and CS radicals in the presence of substrate was found to increase linearly with the H2S concentration, decreasing as the CH4 concentration increases. In the absence of substrate, the concentration of the radicals was found to be higher for higher values of the H2S concentration and increase as the CH4 concentration increased. These finding suggest that the heterogeneous processes introduced by the presence of the substrate are

  5. Ulnar nerve reconstruction with an expanded polytetrafluoroethylene conduit.

    Science.gov (United States)

    Stanec, S; Stanec, Z

    1998-12-01

    The ulnar nerve of a 22-year-old woman was reconstructed by expanded polytetrafluoroethylene (ePTFE) conduit, 141 days after nerve transection at the distal forearm level. A 2.9 cm nerve gap was bridged by a corrugated, 3.9 cm long, 6 mm diameter ePTFE tube. At final evaluation 3 years later the patient achieved excellent motor and sensory recovery. Exploration of the tube, at that time, showed macroscopically normal nerve inside the conduit. PMID:10209470

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. A method to improve the accuracy of continuous measuring of vertical profiles of temperature and water vapor density by means of a ground-based microwave radiometer

    Science.gov (United States)

    Sánchez, J. L.; Posada, R.; García-Ortega, E.; López, L.; Marcos, J. L.

    2013-03-01

    Many of the meteorological phenomena occurring at meso-? require observations sufficiently close together in time and space. The multichannel microwave radiometer (MMWR) provides continuous temperature and humidity profiles. We demonstrate a method for profile bias correction that significantly improves vertical temperature (T) and water vapor density (?wv) profile accuracy. We compared MMWR temperature (TRD) and humidity (?wvRD) profiles during winter in the Sierra of Guadarrama (Madrid) at 1150 m altitude with thousands of radiosonde temperature (TRW) and humidity (?wvRW) soundings from a launch site at 610 m altitude and 50 km distance. In spite of relatively large horizontal and vertical separation between the two sites, sounding differences above the boundary layer are comparable to observation error typically assigned to radiosonde soundings when they are assimilated into numerical weather models. Systematic bias between the paired values of TRW and TRD and ?wvRW and ?wvRD ranges from 0.2 to 1.2 K and 0.05 to 0.5 g m- 3. This bias can be removed using a corrector function that is applied at each T and ?wv level. Using this method, the bias for both variables is reduced to insignificant levels and their accuracy is significantly improved.

  8. Sciatic nerve repair using adhesive bonding and a modified conduit.

    Science.gov (United States)

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

    2014-03-15

    When repairing nerves with adhesives, most researchers place glue directly on the nerve stumps, but this method does not fix 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 repaired it using a modified 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 modified conduit. The results demonstrated that for the same conduit, the average operation time using the adhesive method was much shorter than with the suture method. No significant 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 modified conduit is feasible and effective, and reduces the operation time while providing an equivalent repair effect. PMID:25206861

  9. Catalytic hydrogenation process and apparatus with improved vapor liquid separation

    Science.gov (United States)

    Chervenak, Michael C. (Pennington, NJ); Comolli, Alfred G. (Trenton, NJ)

    1980-01-01

    A continuous hydrogenation process and apparatus wherein liquids are contacted with hydrogen in an ebullated catalyst reaction zone with the liquids and gas flowing vertically upwardly through that zone into a second zone substantially free of catalyst particles and wherein the liquid and gases are directed against an upwardly inclining surface through which vertical conduits are placed having inlet ends at different levels in the liquid and having outlet ends at different levels above the inclined surface, such that vapor-rich liquid is collected and discharged through conduits terminating at a higher level above the inclined surface than the vapor-poor liquid which is collected and discharged at a level lower than the inclined surface.

  10. Repair of long-gap esophageal atresia: gastric conduits may improve outcome-a 20-year single center experience.

    Science.gov (United States)

    Hunter, Catherine J; Petrosyan, Mikael; Connelly, Meghan E; Ford, Henri R; Nguyen, Nam X

    2009-08-26

    INTRODUCTION: Treatment of long-gap esophageal atresia (LEA) is a major challenge. Options for reconstruction include native esophagus, or replacement with stomach, colon, or small intestine. However, debate continues regarding the optimal conduit for esophageal replacement. METHODS: Medical records of patients with a diagnosis of esophageal atresia during a 20-year period were reviewed. RESULTS: Twenty-eight cases of LEA were identified. Ten patients underwent primary anastomosis either after serial pouch dilations (9/10) and/or after a lengthening procedure (2/10). Nine received colonic interpositions, and the remainder were reconstructed with a gastric tube (n = 3), or gastric interposition (n = 2). One patient died prior to repair, and two await definitive treatment. Repeat esophageal reconstruction was required in four patients because of conduit ischemia. Two ischemic events occurred in the colonic interposition group, and two in the native esophageal repairs. All patients, except one who relocated, received long-term follow-up (mean 4.2 years: range 0.5-11.5 years). CONCLUSIONS: Surgeon's expertise and patient's anatomy should be considered when selecting an appropriate operation for LEA. Although native esophagus is generally preferred, it is associated with a high rate of stricture. Although our study has a limited by numbers, we found that patients with gastric conduits had lower complication rates and no conduit ischemia. We suggest that gastric transposition may be favored as an initial reconstructive option. PMID:19707773

  11. Interactions of large amplitude solitary waves in viscous fluid conduits

    CERN Document Server

    Lowman, Nicholas K; El, Gennady A

    2013-01-01

    The free interface separating an exterior, viscous fluid from an intrusive conduit of buoyant, less viscous fluid is known to support strongly nonlinear solitary waves due to a balance between viscosity-induced dispersion and buoyancy-induced nonlinearity. The overtaking, pairwise interaction of weakly nonlinear solitary waves has been classified theoretically for the Korteweg-de Vries equation and experimentally in the context of shallow water waves. We use numerical simulations and experimental observations to extend the classification scheme to the strongly nonlinear regime for viscous conduit solitary waves, where we identify three classes of nonlinear interaction behavior: purely bimodal, purely unimodal, and a mixed type. The magnitude of the dispersive radiation due to solitary wave interactions is quantified numerically and observed to be beyond the sensitivity of our experiments, suggesting that conduit solitary waves are approximately solitons. Experimental data are shown to be in excellent agreemen...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Method and means for disposal of radioactive waste

    International Nuclear Information System (INIS)

    An apparatus is provided for preparing dry particulate waste material for storage within a container, comprising a source of waste, a conduit to receive the waste from the source and deliver it to a container through a detachable connection, and pressure control means to maintain the pressure in the conduit and container lower than the pressure surrounding the detachable connection. A fluid-tight vessel may surround the container and connection which is maintained at a pressure higher than that in the container and conduit. Means are provided to solidify the waste in the container

  14. 26 CFR 1.67-3 - Allocation of expenses by real estate mortgage investment conduits.

    Science.gov (United States)

    2010-04-01

    ...estate mortgage investment conduits. 1...CONTINUED) Definition of Gross Income...estate mortgage investment conduits. ...year. (3) Returns to the Internal...an information return on Form 1099...allocation of allocable investment expenses is...

  15. AC loss characteristics of simulated CIC-type conductors having plastic conduit

    International Nuclear Information System (INIS)

    When alternating current superconducting coils having cable-in-conduit conductors are fabricated, non-metallic conduit materials are necessary to avoid eddy current losses in the conduits. Using two kinds of non-metallic tapes made of glass fiber reinforced plastics (GFRPs) and Dyneema fiber reinforced plastics (DFRPs), we made the conductors with the GFRP conduits and DFRP conduits, and experimentally studied the total losses of the conductors. The measured results showed that the total loss of the conductor with the GFRP conduit was smaller than that with the DFRP conduit at the same value of the void ratio, the transport current, the external magnetic field, and so on. When the void ratios become high, the superconducting bundle cable can easily move in the conduit. Hence the measured total losses increased with the void ratios of the conductors

  16. 78 FR 66355 - Pleasant Grove City, UT; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-11-05

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  17. 78 FR 61985 - City of Astoria, Oregon; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-10-09

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  18. 78 FR 61987 - Corbett Water District; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-10-09

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  19. 78 FR 53752 - City of Sandpoint, Idaho; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-08-30

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  20. 78 FR 56872 - City of Barre, Vermont; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-09-16

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  1. 78 FR 62351 - North Side Canal Company; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-10-18

    ...Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and...intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of...Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of...

  2. Silk Fibroin Conduits: A Cellular and Functional Assessment of Peripheral Nerve Repair

    OpenAIRE

    Ghaznavi, Amir Mahan; Kokai, Lauren E.; Lovett, Michael L.; Kaplan, David L.; Marra, Kacey G

    2011-01-01

    Novel silk fibroin conduits were designed with appropriate porosity for peripheral nerve repair. The aim of this work was to utilize these conduits to examine cell inflammatory responses and functional recovery in a sciatic nerve defect model.

  3. 26 CFR 1.881-4 - Recordkeeping requirements concerning conduit financing arrangements.

    Science.gov (United States)

    2010-04-01

    26 Internal Revenue 9 2010-04-01...requirements concerning conduit financing arrangements. 1...Section 1.881-4 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT...requirements concerning conduit financing arrangements....

  4. Structure of a bacterial cell surface decaheme electron conduit

    Science.gov (United States)

    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...

  5. Aorto-conduit fistula developing four years after esophagectomy

    OpenAIRE

    Strong, S.; Higgs, S.; Streets, C.; Titcomb, D.; Barham, P.; Blazeby, J.; Hollowood, A.

    2012-01-01

    A 71 year old lady was treated for a squamous cell carcinoma of the oesophagus with neo-adjuvant chemotherapy followed by a two phase Ivor-Lewis oesophagectomy with two field lymphadenectomy. She presented four years later with life threatening bleeding from a fistula between the thoracic aorta and the gastric conduit, which was treated successfully with a thoracic aortic stent.

  6. Evaluation of the MODFLOW-2005 Conduit Flow Process.

    Science.gov (United States)

    Hill, Melissa E; Stewart, Mark T; Martin, Angel

    2010-01-01

    The recent development of the Conduit Flow Process (CFP) by the U.S. Geological Survey (USGS) provides hydrogeologic modelers with a new tool that incorporates the non-Darcian, multiporosity components of flow characteristic of karst aquifers. CFP introduces new parameters extending beyond those of traditional Darcian groundwater flow codes. We characterize a karst aquifer to collect data useful for evaluating this new tool at a test site in west-central Florida, where the spatial distribution and cross-sectional area of the conduit network are available. Specifically, we characterize: (1) the potential for Darcian/non-Darcian flow using estimates of specific discharge vs. observed hydraulic gradients, and (2) the temporal variation for the direction and magnitude of fluid exchange between the matrix and conduit network during extreme hydrologic events. We evaluate the performance of CFP Mode 1 using a site-scale dual-porosity model and compare its performance with a comparable laminar equivalent continuum model (ECM) using MODFLOW-2005. Based on our preliminary analyses, hydraulic conductivity coupled with conduit wall conductance improved the match between observed and simulated discharges by 12% to 40% over turbulent flow alone (less than 1%). PMID:20113361

  7. Orienting neurite growth in electrospun fibrous neural conduits.

    Science.gov (United States)

    Yao, Li; O'Brien, Norah; Windebank, Anthony; Pandit, Abhay

    2009-08-01

    In cases where direct suture of two nerve stumps is not feasible, generally a scaffold is required to bridge the gap and guide nerve regeneration. The scaffold used in nerve tissue engineering applications requires optimal guidance effect, mechanical strength, and cellular compatibility. A number of studies suggest that fibrous scaffolds can potentially be used for nerve regeneration, as the aligned fibers can provide the guidance effect for axonal growth and the fibrous structure mimics the nerve microenvironment. A practical method to fabricate the fibrous nerve conduit with structural guidance cue for neurite growth will improve its potential application in neural tissue engineering. In this study, fibrous tubular scaffolds were fabricated using an electrospinning technique. The fibrous conduit was composed of aligned fibers in the interior layer and randomly oriented fibers in the exterior layer. In order to investigate the fiber diameter on neurite extension and directional growth, fibers with different diameter in the subcellular size range were fabricated and the neurite growth on these fibers was investigated. We observed that PC12 cells' neurites showed similar parallel growth on the aligned fibers irrespective of fiber diameter. Neurite length on aligned fibers, with fiber diameters of 3.7 +/- 0.5 microm and 5.9 +/- 0.9 microm, was significantly longer than neurite length on randomly oriented fibers. This study showed that electrospinning provides a practical solution to fabricate fibrous nerve conduit by controlling the conduit inner diameter and fiber alignment and, hence, potentially improves the application of the conduit in neural regeneration. PMID:19130615

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Dolanský, Jind?ich

    2015-05-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Dolanský Jind?ich

    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.

  11. Single-friction-surface triboelectric generator with human body conduit

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Bo; Cheng, Xiaoliang; Zhang, Xiaosheng; Han, Mengdi; Liu, Wen; Zhang, Haixia, E-mail: zhang-alice@pku.edu.cn [National Key Lab of Nano/Micro Fabrication Technology, Peking University, Beijing 100871 (China)

    2014-03-10

    We present a transparent single-friction-surface triboelectric generator (STEG) employing human body as the conduit, making the applications of STEG in portable electronics much more practical and leading to a significant output improvement. The STEG with micro-patterned polydimethylsiloxane surface achieved an output voltage of over 200 V with a current density of 4.7 ?A/cm{sup 2}. With human body conduit, the output current increased by 39% and the amount of charge that transferred increased by 34% compared to the results with grounded electrode. A larger increment of 210% and 81% was obtained in the case of STEG with a large-size flat polyethylene terephthalate surface.

  12. Grading complication following radical cystectomy and ileal conduit for bladder cancer using clavien grading system

    International Nuclear Information System (INIS)

    Objective: To determine the 30-day complication rate of radical cystectomy and urinary diversion using a validated system. Study Design: An analytical descriptive study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from 1990 to 2010. Methodology: Patients who had undergone ileal conduit (IC) formation, following radical cystectomy (RC) for muscle invasive transitional cell carcinoma, were studied, using a prospectively maintained data base. Basic details were determined, complications were noted and graded according to the modified Clavien grading system (CG). Results were presented using descriptive statistics. Results: Of all the RC performed at this hospital 89 patients received IC. Of them 75 were male and 14 female. Mean age was 60 years. Mean duration of hospital stay was 14 days. Ten patients each received pre-operative chemotherapy and radiotherapy, respectively. Mean duration of surgery was 8.2 hours, with mean estimated blood loss of 1334 ml. Preoperative radiotherapy was associated with more complications. No other factor like ASA, co-morbidities, blood loss or duration of stay influenced the complications. Fifty patients (56.2%) did not have any complications. Most common complication of wound infection was seen in 7 patients (CG-2), followed by uretero-ileal leakage in 5, requiring percutaneous intervention under local anaesthesia (GC-3a). Mortality rate was 4.5%, classified as CG-V. Conclusion: Radical cystectomy with Ileal conclusion: Radical cystectomy with Ileal conduit is a major procedure with a good safety profile at this institute. Long term follow up is still needed to evaluate delayed complications and quality of life. (author)

  13. System for continuous real time air monitoring by means of gamma spectrometry with germanium dosimeter

    International Nuclear Information System (INIS)

    Design of automatic system for real time air monitoring of radioactive particulates are relate. Recommendations are made for design and operation of sampling conduits to minimize losses. By means of experimental equipment loss of particles in long sampling conduits, minimum detectable activity and efficiency of gamma radiation detectable are evaluated. (author)

  14. Impulsive Wave Propagation within Magmatic Conduits with Axial Symmetry

    Science.gov (United States)

    De Negri Leiva, R. S.; Arciniega-Ceballos, A.; Scheu, B.; Dingwell, D. B.; Sanchez-Sesma, F. J.

    2013-12-01

    We implemented Trefftz's method to simulate wave propagation in a fluid-solid system aimed to represent a magmatic conduit. Assuming axial symmetry, a set of multipoles is used to build a complete system of wave functions for both the solid and the fluid. These functions are solutions of the elastodynamic equations that govern the motions in the fluid and the solid, respectively. The conduit can be closed or open and the exterior elastic domain may be unlimited or with an exterior boundary. In order to find the functions coefficients, boundary conditions (null shear and continuity of pressures and normal velocities) are satisfied in the least squares sense. The impulsive nature of the source is considered using Fourier analysis. Despite the simplicity of the formulation our results display a rich variety of behaviors. In fact, for a uniform infinite cylinder we reproduced the analytical solution. Moreover, this approach allows establishing some important effects of conduit geometry, including changes of sections. Lateral effects and bump resonances are well resolved. We compared our numerical calculations with results obtained from experimental simulations of volcanic explosions in which rapid depressurization induces fragmentation of volcanic rocks. These experiments are performed within a shock-tube apparatus at room temperature and various pressures using Argon (Ar) gas, particles and pumice samples of different porosities, from Popocatepetl volcano. The mechanical system is well characterized and the dynamics of the explosive process is monitored with high precision piezoelectric sensors located at the pipe surface. The combination of analytical and experimental approaches is very useful to understand the seismic wave field of volcanic conduit dynamics.

  15. Studies on forced convection nanofluid flow in circular conduits

    OpenAIRE

    Harikrishna Vishwanadula; Emmanuel C. Nsofor

    2012-01-01

    An experimental system was developed and used to study the nanofluid flow and heat transfer in circular conduits. Experiments were performed for a variety of nanofluid flow features in the system. Results obtained from the study show that the heat transfer rate for flow of the base fluid is less than that of the nanofluid used in the study. It was also found that the observed relationship between molecular diffusivity of momentum and the molecular diffusivity of thermal energy at the macrosca...

  16. Free-boundary models of a meltwater conduit

    Science.gov (United States)

    Dallaston, Michael C.; Hewitt, Ian J.

    2014-08-01

    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.

  17. Frictional melting and stick-slip behavior in volcanic conduits

    Science.gov (United States)

    Kendrick, Jackie Evan; Lavallee, Yan; Hirose, Takehiro; di Toro, Giulio; Hornby, Adrian Jakob; Hess, Kai-Uwe; Dingwell, Donald Bruce

    2013-04-01

    Dome-building eruptions have catastrophic potential, with dome collapse leading to devastating pyroclastic flows with almost no precursory warning. During dome growth, the driving forces of the buoyant magma may be superseded by controls along conduit margins; where brittle fracture and sliding can lead to formation of lubricating cataclasite and gouge. Under extreme friction, pseudotachylyte may form at the conduit margin. Understanding the conduit margin processes is vital to understanding the continuation of an eruption and we postulate that pseudotachylyte generation could be the underlying cause of stick-slip motion and associated seismic "drumbeats", which are so commonly observed at dome-building volcanoes. This view is supported by field evidence in the form of pseudotachylytes identified in lava dome products at Soufrière Hills (Montserrat) and Mount St. Helens (USA). Both eruptions were characterised by repetitive, periodic seismicity and lava spine extrusion of highly viscous magma. High velocity rotary shear (HVR) experiments demonstrate the propensity for melting of the andesitic and dacitic material (from Soufrière Hills and Mount St. Helens respectively) at upper conduit stress conditions (speed that is achievable during stick-slip motion). At lower velocities melting occurs comparatively later due to dissipation of heat from the slip zone (e.g. 8-15 m at 0.1 m/s). Hence, given the ease with which melting is achieved in volcanic rocks, and considering the high ambient temperatures in volcanic conduits, frictional melting may thus be an inevitable consequence of viscous magma ascent. The shear resistance of the slip zone during the experiment is also monitored. Frictional melting induces a higher resistance to sliding than rock on rock, and viscous processes control the slip zone properties. Variable-rate HVR experiments which mimic rapid velocity fluctuations in stick-slip behavior demonstrate velocity-weakening behavior of melt, with a tendency for unstable slip. During ascent, magma may slip and undergo melting along the conduit margin. In the process the shear resistance of the slip zone is increased, acting as a viscous brake halting slip (the "stick" of stick-slip motion). Sufficient buoyancy-driven pressures from ascending magma below eventually overcome resistance to produce a rapid slip event (the "slip") along the melt-bearing slip zone, which is temporarily lubricated due to velocity-weakening. New magma below experiences the same slip event more slowly (as the magma decompresses) to produce a viscous brake and the process is repeated. This allows a fixed spatial locus that explains the repetitive drumbeat seismicity and the occurrence of "families" of similar seismic events. We conclude that stick-slip motion in volcanic conduits is a self-driving, frictional-melt-regulated force common to many dome building volcanoes.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. ESTUDIO DE LAS CONDICIONES DE EXTRACCIÓN POR ARRASTRE CON VAPOR DEL ACEITE ESENCIAL DE LAUREL DE CERA (Morella pubescens) / STUDY OF EXTRACTION CONDITIONS OF "LAUREL DE CERA" (Morella pubescens) ESSENTIAL OIL BY MEANS OF STEAM DISTILLATION

    Scientific Electronic Library Online (English)

    OSCAR, ARANGO; ANDRÉS, HURTADO; PATRICIA, CASTILLO; MÓNICA, SANTACRUZ.

    2009-12-01

    Full Text Available El laurel de cera (Morella pubescens) es un árbol que por sus características resulta muy apropiado para el control de la erosión, y cuyos frutos son utilizados por comunidades campesinas del sur de Colombia para la obtención de una cera que se emplea en el proceso de elaboración de la panela. En es [...] ta investigación se estudió el proceso de extracción del aceite esencial de las hojas del laurel de cera mediante la técnica de arrastre con vapor, y su efecto sobre la composición de los metabolitos secundarios volátiles presentes en dicho aceite. Los factores estudiados en el proceso de extracción fueron el tamaño de partícula y el tiempo de extracción, y las variables de respuesta consideradas fueron el área total del cromatograma (cuentas) como parámetro indicador de la concentración del aceite y el porcentaje relativo del componente mayoritario. Se determinó que tanto el tiempo como la interacción tiempo - tamaño de partícula tienen efectos significativos (valor de P Abstract in english Because of its characteristics, the "Laurel de Cera" tree (Morella pubescens) proves to be very appropriate for the erosion control. Its fruits are employed as a means to obtain wax that is used in the process of making Panela by rural communities settled in the southern region of Colombia. The extr [...] action process of essential oil from "Laurel de Cera" tree leaves through steam distillation and its effects over the composition of volatile secondary metabolites present were considered for the research. Particle size and extraction time were the studied factors. The chromatogram total area (counts) taken as the oil concentration indicator parameter and the relative percentage were the considered response variables. According to the previous information, it was possible to determine that the time as well as the interaction time - particle size have significant effects (P-value

  20. Regulation of cell division by intrinsically unstructured proteins: intrinsic flexibility, modularity, and signaling conduits.

    Science.gov (United States)

    Galea, Charles A; Wang, Yuefeng; Sivakolundu, Sivashankar G; Kriwacki, Richard W

    2008-07-22

    It is now widely recognized that intrinsically unstructured (or disordered) proteins (IUPs or IDPs) are found in organisms from all kingdoms of life. In eukaryotes, IUPs are highly abundant and perform a wide range of biological functions, including regulation and signaling. Despite an increased level of interest in understanding the structural biology of IUPs and IDPs, questions regarding the mechanisms through which disordered proteins perform their biological function(s) remain. In other words, what are the relationships between disorder and function for IUPs? There are several excellent reviews that discuss the structural properties of IUPs and IDPs since 2005 [Receveur-Brechot, V., et al. (2006) Proteins 62, 24-45; Mittag, T., and Forman-Kay, J. D. (2007) Curr. Opin. Struct. Biol. 17, 3-14; Dyson, H. J., and Wright, P. E. (2005) Nat. Rev. Mol. Cell Biol. 6, 197-208]. Here, we briefly review general concepts pertaining to IUPs and then discuss our structural, biophysical, and biochemical studies of two IUPs, p21 and p27, which regulate the mammalian cell division cycle by inhibiting cyclin-dependent kinases (Cdks). Some segments of these two proteins are partially folded in isolation, and they fold further upon binding their biological targets. Interestingly, some portions of p27 remain flexible after binding to and inhibiting the Cdk2-cyclin A complex. This residual flexibility allows otherwise buried tyrosine residues within p27 to be phosphorylated by non-receptor tyrosine kinases (NRTKs). Tyrosine phosphorylation relieves kinase inhibition, triggering Cdk2-mediated phosphorylation of a threonine residue within the flexible C-terminus of p27. This, in turn, marks p27 for ubiquitination and proteasomal degradation, unleashing full Cdk2 activity which drives cell cycle progression. p27, thus, constitutes a conduit for transmission of proliferative signals via post-translational modifications. The term "conduit" is used here to connote a means of transmission of molecular signals which, in the case of p27, correspond to tyrosine and threonine phosphorylation, ubiquitination, and, ultimately, proteolytic degradation. Transmission of these multiple signals is enabled by the inherent flexibility of p27 which persists even after tight binding to the Cdk2-cyclin A complex. Importantly, activation of the p27 signaling conduit by oncogenic NRTKs contributes to tumorigenesis in some human cancers, including chronic myelogenous leukemia (CML) [Grimmler, M., et al. (2007) Cell 128, 269-280] and breast cancer [Chu, I., et al. (2007) Cell 128, 281-294]. Other IUPs may participate in conceptually similar molecular signaling conduits, and dysregulation of these putative conduits may contribute to other human diseases. Detailed study of these IUPs, both alone and within functional complexes, is required to test these hypotheses and to more fully understand the relationships between protein disorder and biological function. PMID:18627125

  1. Influence of irradiation sterilization on mechanical properties and biodegradability of chitosan conduits

    International Nuclear Information System (INIS)

    Chitosan conduits were sterilized with 60Co ? ray irradiation at a dose of 25 kGy and their swelling properties, mechanical properties and biodegradability in lysozyme solution were measured. After ? ray irradiation, the swelling index of chitosan conduit was considerably reduced and the tensile strength and elastic modulus were markedly increased. The results from SEM and measurement of mechanical properties showed that the degradation rate of the irradiated conduits in lysozyme solution was lower than that of the nonirradiated conduits. In addition, the chitosan conduits were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimeter (DSC), and the influence mechanism of irradiation sterilization on the properties of chitosan conduits was explored. (authors)

  2. Imaging of platelets in right-sided extracardiac conduits in humans

    International Nuclear Information System (INIS)

    As a connection between the systemic venous ventricle and the pulmonary artery, valved Dacron extracardiac conduits have remarkably influenced the surgical approach to many complex congenital heart defects. Obstruction of the conduit, however, can reduce the long-term effectiveness of this corrective procedure. In addition to stenosis of the porcine valve, formation of thick fibrous neointima plays a major role in the pathogenesis of conduit obstruction. The purpose of this study was to determine whether platelet deposition could be demonstrated in these conduits by external imaging with 111In-labeled autologous platelets. After injection of labeled platelets either immediately after operation or on the fifth to eighth postoperative day, imaging was performed by standard procedures. Eight of nine patients had platelet accumulation in the conduit, and treatment with aspirin and dipyridamole caused no recognizable change in platelet deposition. This study demonstrates the feasibility of imaging platelet deposition in Dacron conduits and shows that the pattern of deposition varies with time

  3. Arctic Water Vapor Characteristics from Rawinsondes

    National Aeronautics and Space Administration — A gridded climatological monthly-mean data base of Arctic water vapor characteristics has been assembled by combining fixed station data with data from soundings...

  4. Evaluation of the ITER cable in conduit conductor heat transfer

    International Nuclear Information System (INIS)

    Convective heat transfer correlations in dual channel Cable In Conduit Conductor (CICC) are presented as functions of friction factor, and based on the Reynolds-Colburn analogy using the Stanton number. The developed thermohydraulic model determines helium temperatures in both channels, with the real geometrical spiral perforation. It is applied with pertinence to the Poloidal Field Full Size Joint Sample (PF-FSJS) and shows good agreement between the experimental measurements and the calculated temperatures, characterised by a 0.43 m space constant. The heat load applied in the bundle region induces density imbalance; the gravity effect in this vertical sample is evaluated and discussed. (authors)

  5. Heating-induced flows in cable-in-conduit conductors

    International Nuclear Information System (INIS)

    Hoenig et al and Miller et al have both reported high stability margins for cable-in-conduit conductors cooled by stationary supercritical helium. Miller et al proposed that strong flows induced in the helium in the early stages of recovery enhanced heat transfer and greatly increased the stability margin over what had been expected for stationary helium. In this memorandum, the flow and pressure transients induced in initially stationary helium by energy transfers typical of those associated with conductor recovery (50 to 200 mJ cm-3 in 10 to 20 msec) are calculated

  6. Modeling flow in phreatic and epiphreatic Karst conduits in the Hölloch Cave (Muotatal, Switzerland)

    Science.gov (United States)

    Jeannin, Pierre-Yves

    2001-02-01

    The Hölloch cave is a site where the hydrodynamic behavior of a karst conduit network can be observed with a high degree of precision. Observed heads, discharge rates, conduit sizes, and conduit lengths have been compiled into a simple hydrodynamic model in order to check their consistency. It was possible to calibrate and satisfactorily fit the observed data. Model results show the following: (1) Flow models which are able to simulate turbulent flow in variably saturated conduit networks can adequately model conduit flow-dominated karst systems. (2) Karst systems may be strongly nonlinear, especially because of the presence of epiphreatic conduits. (3) Under certain circumstances, storage in the epiphreatic conduits and in the fissured limestone matrix can be neglected. (4) The typical effective hydraulic conductivity of karst conduits ranges between 1 and 10 m s-1, and the Louis formula is adequate to calculate head losses in those conduits. (5) Indirect measurements of flow velocity using scallop size indicate values of ˜30-40% of the maximal annual discharge, and velocity derived from pebble size indicates values of ˜150% of the maximal annual discharge.

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

    Science.gov (United States)

    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, long bone, intestine, or blood vessel.

  8. ESTUDIO DE LAS CONDICIONES DE EXTRACCIÓN POR ARRASTRE CON VAPOR DEL ACEITE ESENCIAL DE LAUREL DE CERA (Morella pubescens STUDY OF EXTRACTION CONDITIONS OF "LAUREL DE CERA" (Morella pubescens ESSENTIAL OIL BY MEANS OF STEAM DISTILLATION

    Directory of Open Access Journals (Sweden)

    OSCAR ARANGO

    2009-12-01

    Full Text Available El laurel de cera (Morella pubescens es un árbol que por sus características resulta muy apropiado para el control de la erosión, y cuyos frutos son utilizados por comunidades campesinas del sur de Colombia para la obtención de una cera que se emplea en el proceso de elaboración de la panela. En esta investigación se estudió el proceso de extracción del aceite esencial de las hojas del laurel de cera mediante la técnica de arrastre con vapor, y su efecto sobre la composición de los metabolitos secundarios volátiles presentes en dicho aceite. Los factores estudiados en el proceso de extracción fueron el tamaño de partícula y el tiempo de extracción, y las variables de respuesta consideradas fueron el área total del cromatograma (cuentas como parámetro indicador de la concentración del aceite y el porcentaje relativo del componente mayoritario. Se determinó que tanto el tiempo como la interacción tiempo - tamaño de partícula tienen efectos significativos (valor de PBecause of its characteristics, the "Laurel de Cera" tree (Morella pubescens proves to be very appropriate for the erosion control. Its fruits are employed as a means to obtain wax that is used in the process of making Panela by rural communities settled in the southern region of Colombia. The extraction process of essential oil from "Laurel de Cera" tree leaves through steam distillation and its effects over the composition of volatile secondary metabolites present were considered for the research. Particle size and extraction time were the studied factors. The chromatogram total area (counts taken as the oil concentration indicator parameter and the relative percentage were the considered response variables. According to the previous information, it was possible to determine that the time as well as the interaction time - particle size have significant effects (P-value <0,05 over the essential oil's concentration. It was also possible to observe a meaningful increment in the chromatogram's area for the majority component when the extraction time was increased. The identification of the volatile secondary metabolites present in the essential oil was carried out through a gas chromatography/mass spectrometry (GC-MS. Such procedure gave as results trans caryophyllene (23,3%, ?-selinene (10,7%, ?-selinene (10,0% caryophyllene oxide (4,8%, seline-3,7(11-diene (3,3% and ?-elemene (2,6% as majority components. These compounds' biological activities allow thinking that the essential oil from the "Laurel de Cera" tree leaves could be of great interest for the pharmabusiness and the cosmetic industries.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

    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, tipo de desgaste o dano, se desarrollaron los procedimientos especiales basados en procesos de soldadura. El proceso de recuperacion de alabes incluye tambien: relevado de esfuerzos, maquinado, recubrimiento especial, control de calidad y diseno del herramental. Una vez terminado el proceso de recuperacion, los componentes se instalaron nuevamente en las turbinas para su servicio. La aplicacion de las tecnologias de soldadura desarrolladas para recuperar los alabes, representa una fraccion del costo de alabes nuevos, lo que resulta en un ahorro economico.

  10. Nuclear system vaporization

    International Nuclear Information System (INIS)

    A particular case of the hot nuclei de-excitation is the total nuclear dislocation into light particles (n, p, d, t, 3He and ?). Such events were first observed at bombarding energies lower than 100 MeV/nucleon due to high detection performances of the INDRA multidetector. The light system Ar + Ni was studied at several bombarding energies ranging from 32 to 95 MeV/nucleon. The events associated to a total vaporization of the system occur above the energy threshold of ? 50 MeV/nucleon. A study of the form of these events shows that we have essentially two sources. The excitation energy of these sources may be determined by means of the kinematic properties of their de-excitation products. A preliminary study results in excitation energy values of the order 10 - 14 MeV/nucleon. The theoretical calculation based on a statistical model modified to take into account high excitation energies and excited levels in the lightest nuclei predicts that the vaporization of the two partner nuclei in the Ar + Ni system takes place when the excitation energy exceeds 12 MeV/nucleon what is qualitatively in agreement with the values deduced from calorimetric analysis

  11. Twenty years of cable-in-conduit conductors: 1975-1995

    International Nuclear Information System (INIS)

    This paper reviews our progress during the last two decades in understanding cable-in-conduit conductors. The emphasis is on the physical principles governing the behavior of cable-in-conduit conductors, and no detailed mathematics is presented. The paper is constructed as a historical narrative

  12. Staghorn calculus due to migration of foreign body: unusual complication of ileal conduit.

    Science.gov (United States)

    Hampel, N; Kursh, E D; Persky, L

    1978-07-01

    An unusual late complication of ileal conduit diversion is described. To our knowledge this is the first case reported in which a foreign body apparently migrated from an ileal conduit to the renal pelvis and served as a nidus for stone formation. PMID:356392

  13. A one-dimensional heat-transport model for conduit flow in karst aquifers

    Science.gov (United States)

    Long, A.J.; Gilcrease, P.C.

    2009-01-01

    A one-dimensional heat-transport model for conduit flow in karst aquifers is presented as an alternative to two or three-dimensional distributed-parameter models, which are data intensive and require knowledge of conduit locations. This model can be applied for cases where water temperature in a well or spring receives all or part of its water from a phreatic conduit. Heat transport in the conduit is simulated by using a physically-based heat-transport equation that accounts for inflow of diffuse flow from smaller openings and fissures in the surrounding aquifer during periods of low recharge. Additional diffuse flow that is within the zone of influence of the well or spring but has not interacted with the conduit is accounted for with a binary mixing equation to proportion these different water sources. The estimation of this proportion through inverse modeling is useful for the assessment of contaminant vulnerability and well-head or spring protection. The model was applied to 7 months of continuous temperature data for a sinking stream that recharges a conduit and a pumped well open to the Madison aquifer in western South Dakota. The simulated conduit-flow fraction to the well ranged from 2% to 31% of total flow, and simulated conduit velocity ranged from 44 to 353 m/d.

  14. MR jet velocity mapping for assessment of conduit and valve stenosis and aortic coarctation

    International Nuclear Information System (INIS)

    This paper assesses short echo time MR jet velocity mapping as a means of measuring poststenotic jet velocities in vitro and in patients. MR jet velocity mapping was performed with a Picker 0.5-T machine and the field even-echo rephasing sequence with a 3.6-msec echo time, in stenotic flow phantoms and in 49 patients (mean age, 31 years; range, 12-72 years) with stenoses of valved conduits (n = 22), native heart valves (n = 123), and aortic coarctation (n = 15). Where possible, results were compared with those available from Doppler US and catheter studies. MR velocity maps clearly demonstrated the shape and location of jets, and velocity measurements correlated well with Doppler measurements up to 6 m/sec in vitro (r = .996). In patients, jet velocities up to 5.5 m/sec were mapped, and for 21 cases in which comparison was possible, agreement with Doppler was good (means of peak velocity measurements, 2.7 m/sec; standard deviation of differences, 0.2 m/sec). Unclear velocity maps were attributed to slight misplacement of the image plane in seven cases

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

    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 corrientes parasitas y por la magnetizacion del metal en estas tuberias conduit. Al mismo tiempo se cuantifica el impacto de estas corrientes diferenciales en la reactancia de la instalacion electrica. Se muestran los resultados obtenidos para doce tubos de diferente diametro y espesor de pared. Se hace un analisis comparativo con los resultados reportados en un articulo anterior, donde las perdidas se estimaron mediante la medicion del incremento de temperatura de la pared metalica.

  16. Laser beam welding of advanced superconducting cable conduits

    International Nuclear Information System (INIS)

    The present work describes the experience gained with the laser beam welding of various types of stainless steel used in different conduit designs for advanced superconducting cables in fusion technology. The aim of this work is to show the continuous laser beam welding of long units on an assembly line, which is essential for an industrial cable production. Preliminary investigations and test results of weld performance obtained with different multikilowatt power CO2 type laser work stations are encouraging for a near term use of the laser weld processing in this particular aspect. The analysis confirms that laser beam welding has prospects which makes it feasible for industrial manufacturing process combined with good economics

  17. Hot upwelling conduit beneath the Atlas Mountains, Morocco

    Science.gov (United States)

    Sun, Daoyuan; Miller, Meghan S.; Holt, Adam F.; Becker, Thorsten W.

    2014-11-01

    The Atlas Mountains of Morocco display high topography, no deep crustal root, and regions of localized Cenozoic alkaline volcanism. Previous seismic imaging and geophysical studies have implied a hot mantle upwelling as the source of the volcanism and high elevation. However, the existence, shape, and physical properties of an associated mantle anomaly are debated. Here we use seismic waveform analysis from a broadband deployment and geodynamic modeling to define the physical properties and morphology of the anomaly. The imaged low-velocity structure extends to ~200 km beneath the Atlas and appears ~350 K hotter than the ambient mantle with possible partial melting. It includes a lateral conduit, which suggests that the Quaternary volcanism arises from the upper mantle. Moreover, the shape and temperature of the imaged anomaly indicate that the unusually high topography of the Atlas Mountains is due to active mantle support.

  18. Extrinsic airway compression secondary to pulmonary arterial conduits: MR findings

    International Nuclear Information System (INIS)

    Abnormal enlargement or malposition of any vascular structure or mass adjacent to the airway can cause extrinsic airway compression. In children with previous surgery for congenitial heart disease, mass effect from prosthetic devices or alteration in the anatomic position of normal structures can lead to extrinsic airway compression. Because many children have complex medical problems after cardiac surgery, wheezing may be attributed to cardiac causes and airway compression may not be investigated. Furthermore, the distal airway compression seen in these children often is not visualized on chest radiographys. MR imaging can be useful in evaluating extrinsic airway compression in these patients. We present the MR imaging of two patients with symptomatic extrinsic airway compression secondary to pulmonary arterial conduits. (orig.)

  19. 26 CFR 1.67-3T - Allocation of expenses by real estate mortgage investment conduits (temporary).

    Science.gov (United States)

    2010-04-01

    ...real estate mortgage investment conduits (temporary...TAXES (CONTINUED) Definition of Gross Income, Adjusted...real estate mortgage investment conduits (temporary...make an information return on Form 1099 for each...allocation of allocable investment expenses is...

  20. 26 CFR 1.6081-7 - Automatic extension of time to file Real Estate Mortgage Investment Conduit (REMIC) income tax...

    Science.gov (United States)

    2010-04-01

    ...Real Estate Mortgage Investment Conduit (REMIC...file an income tax return on Form 1066, “U...Real Estate Mortgage Investment Conduit Income Tax Return,” or Form 8831...guidance regarding the definition of last known...

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

    Science.gov (United States)

    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 hydrogel. This indicates return of some feeling to the limb via the fully-configured conduit. Immunohistochemical analysis of the implanted conduits removed from the rats after the four-week implantation period confirmed the presence of myelinated axons within the conduit and distal to the site of implantation, further supporting that the conduit promoted nerve repair over this period of time. This study describes the design considerations and fabrication of a novel multicomponent, multimodal bio-engineered synthetic conduit for peripheral nerve repair.

  2. Influence of conduit network geometry on solute transport in karst aquifers with a permeable matrix

    Science.gov (United States)

    Ronayne, Michael J.

    2013-06-01

    In karst aquifers with significant matrix permeability, water and solutes are exchanged between the conduits and carbonate matrix. Transport through the matrix increases the spread of solutes and increases travel times. This study numerically evaluates advective solute transport in synthetic karst systems that contain 3D branching conduit networks. Particle tracking is performed to analyze the spatial and temporal transport history of solute that arrives at the conduit outlet. Three measures of transport connectivity are used to quantify the solute migration behavior: the skewness of the particle arrival time distribution, the normalized fifth percentile of arrival times, and the fraction of the total travel time that occurs within conduits. All three of these metrics capture the influence of conduit network geometry on solute transport. A more tortuous network leads to enhanced conduit-matrix mixing, which reduces the transport connectivity and yields a broader distribution of solute arrival times. These results demonstrate that the conduit network geometry is an important control on solute transport in karst systems with a permeable matrix.

  3. Data Transfer via Alternative Conduits: Using Fluid Networks

    Directory of Open Access Journals (Sweden)

    Charles Willow

    2012-11-01

    Full Text Available Digital convergence has reshaped a gamut of industry demographics in the 21C, comprised of cloud computing, healthcare, pharmaceutical, consumer supplies, government, defense, manufacturing, entertainment, and even on-line education, among many others.   At the center of the web-convergence lies the problem of network bandwidth limitation.  Traditionally, research has focused on two major resolution strategies in parallel:  data compression to minimize the network traffic (i.e. algorithmic; software and alternative conduit for data transfer such as wireless (i.e. infrastructural; hardware.Building a network infrastructure is extremely costly.   In addition, maintenance and upgrade costs may be prohibitive, given the U.S. consumer demographics.   To this end, the emphasis is placed on seeking existing infrastructure which connects business and residential entities.The objective of this research, therefore, is to seek the possibility and feasibility of (digital data transfers via the extensive water and/or sewer network(s, while minimizing structural modifications to the existing infrastructure.   To date, sonar has been proven to be effective.   If successful, the value of this intellectual property may be immeasurable.

  4. Injunctions against mere conduit of information protected by copyright

    DEFF Research Database (Denmark)

    Sandfeld Jakobsen, SØren; Petersen, Clement Salung

    2011-01-01

    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 attract attention in all European member states. Firstly, it is shown that rules on preliminary injunctions are generally unable to safeguard the significant legitimate interests of third parties, which may be harmed by such relief, and that a proper implementation of Art. 8(3) of the Infosoc Directive 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 and also may restrict the freedom of expression under European human rights law. The analysis is based on a brief account for the relevant EU Directives, the implementation of these Directives in the Scandinavian countries and the Scandinavian case law regarding use of injunctions against IAPs to enforce copyright on the internet.

  5. A conduit dilation model of methane venting from lake sediments

    Science.gov (United States)

    Scandella, B.P.; Varadharajan, C.; Hemond, Harold F.; Ruppel, C.; Juanes, R.

    2011-01-01

    Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

  6. Investigation of entrance length in circular and noncircular conduits by computational fluid dynamics simulation

    Directory of Open Access Journals (Sweden)

    Pimpun Tongpun

    2014-08-01

    Full Text Available This study estimated entrance length of circular and noncircular conduits, including circle, triangle, square and hexagon cross-sectional conduit, by using computational fluid dynamics (CFD. For simulation condition, the length of noncircular conduit was 10 m and the hydraulic diameter was 0.2 m. The laminar flow with Reynolds number of 500 and turbulent flow with Reynolds number of 50,000 were applied to investigate water flow in conduits. The governing equations were solved iteratively by using ANSYS FLUENT 14.0. For turbulent flow simulation, standard k-epsilon and RNG k-epsilon model were employed to simulate turbulence. The preliminary results were validated by comparison with theoretical data. At first, grid independency was evaluated to optimize the model. Norm* was employed to investigate the entrance length, which is related to velocity. The simulated results revealed that the entrance length for laminar flow was longer than turbulent flow.

  7. In vivo visualization of microneedle conduits in human skin using laser scanning microscopy

    International Nuclear Information System (INIS)

    Solid microneedles enhance the penetration of drugs into the viable skin but little is known about the geometry of the conduits in vivo. Therefore, laser scanning microscopy was used to visualize the conduits of a microneedle system with needles at a length of 300 ?m in 6 healthy subjects over a period of time. The model drug, a fluorescent dye was applied before and after piercing. Laser scanning microscopy was evaluated as being an excellent method to monitor the geometry and closure of the conduits over time. The used microneedle system was evaluated as suitable to enhance the transport of model drugs into the viable epidermis without bleeding and a short closure time of the conduits at the skin surface

  8. Local recurrence of bladder cancer after cystectomy with orthotopic bladder substitution and ileal conduit

    Directory of Open Access Journals (Sweden)

    A?imovi? M.

    2007-01-01

    Full Text Available Objective: To present the local recurrence rates after radical cystectomy for advanced bladder cancer and to compare them between patients with orthotopic neobladder and ileal conduit. Patients and methods: 97 patients with radical cystectomy were analyzed: 75 patients with orthotopic ileal neobladder, operated from 1985. to 2006, and 22 patients with ileal conduit, operated from 2000. to 2006. Results: Overall recurrence rate was 41.3% in the neobladder group, and 50% in the ileal conduit group. The rate of pelvic, upper urinary tract and urethral recurrence was 13.3%, 8%, and 10.6% in the neobladder group, and 9.1%, 13.6% and 9.1% in the ileal conduit group. Conclusion: Comparable recurrence rates, operative time, the complexity of the surgical technique and the results between two groups, strongly support the construction of orthotopic neobladder, as superior in functional, esthetic, and psychological point of view.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Convection of magma in volcanic conduits as a degassing mechanism at active volcanoes

    Science.gov (United States)

    Witter, Jeffrey Bruce

    Convection of magma in the volcanic conduit is a hypothesis that has been proposed to explain long-term, continuous, high rates of gas emission and heat loss at non-explosive, passively degassing volcanoes. I investigate this hypothesis using a geochemical and fluid dynamic approach focusing research at two passively degassing volcanoes, Popocatepetl (Mexico) and Villarrica (Chile) where conduit convection is thought to be the dominant degassing mechanism. Popocatepetl has been the site of voluminous passive degassing accompanied by minor eruptive activity from late-1994 until the time of writing. Villarrica has been characterized by continuous, open-vent, passive degassing from a summit lava lake, with negligible eruption of magmatic material, for the past 17 years. I present a detailed analysis of the chemistry and magnitude of volcanic gas emissions as well as the major and volatile element chemistry of the magma at the two volcanoes. These analyses provide constraints on (1) the magmatic contribution to the emitted volatiles and (2) the physical parameters (i.e. density and viscosity of the magma) that control convection. These data on the physical parameters of the Popocatepetl and Villarrica magmas combined with analytical fluid dynamic equations for convection of magma in volcanic conduits show that magma convection is a feasible mechanism to provide the observed magnitude of gas emissions considering reasonable conduit sizes and magma ascent velocities at both volcanoes. Further calculations of the Reynolds number and convective velocity scale are presented for magmas having a wide range of viscosity, buoyancy flux, and conduit size, including both cylindrical and dike-shaped conduits. Results indicate that convection of magma in the conduit is likely at Villarrica for conduit radii r = 1 to 5 m. In addition, convection of magma in the conduit is plausible at Popocatepetl for conduit radii r = 2 to 10 m and magma with or without a separate, pre-existing volatile phase. Convection of magma in the volcanic conduit can explain long-term, non-explosive degassing behavior at Popocatepetl, Villarrica, and probably many other volcanoes for which gas emissions far exceed the quantity of gas that could be derived from erupted magma.

  11. Stratospheric water vapor feedback

    OpenAIRE

    Dessler, A. E.; Schoeberl, M. R.; Wang, T; Davis, S. M.; Rosenlof, K.H.

    2013-01-01

    We show observational evidence for a stratospheric water vapor feedback—a warmer climate increases stratospheric water vapor, and because stratospheric water vapor is itself a greenhouse gas, this leads to further warming. An estimate of its magnitude from a climate model yields a value of +0.3 W/(m2?K), suggesting that this feedback plays an important role in our climate system.

  12. Numerical Modeling of the Thermal Behavior of Corrosion in Conduit in Transient Mode

    OpenAIRE

    Naouar Laaidi; Sougrati Belattar

    2013-01-01

    The conduits in the buildings require a regular and permanent control, in order to avoid the risks of deterioration caused by corrosion. In this paper we present a thermal nondestructive testing method of concrete structures containing a conduit system, based on the analysis by infrared thermography principle and the numerical modeling in three dimensions. The aim is to study the detectability of these pipes in different situations versus time and to give a thermal char...

  13. Increased muscle sympathetic nerve activity acutely alters conduit artery shear rate patterns

    OpenAIRE

    Padilla, Jaume; Young, Colin N.; Simmons, Grant H.; Deo, Shekhar H.; Newcomer, Sean C; Sullivan, John P; Laughlin, M. Harold; Fadel, Paul J.

    2010-01-01

    Escalating evidence indicates that disturbed flow patterns, characterized by the presence of retrograde and oscillatory shear stress, induce a proatherogenic endothelial cell phenotype; however, the mechanisms underlying oscillatory shear profiles in peripheral conduit arteries are not fully understood. We tested the hypothesis that acute elevations in muscle sympathetic nerve activity (MSNA) are accompanied by increases in conduit artery retrograde and oscillatory shear. Fourteen healthy men...

  14. Air-pocket transport in conjunction with bottom-outlet conduits for dams

    OpenAIRE

    Liu, Ting

    2011-01-01

    Undesired air entrainment in bottom outlet conduits of dams may cause pressure transients, leading to conduit vibrations, blowback, discharge pulsation and even cavitation, and jeopardize the operational safety. Due to design limitations or construction costs, it is impossible to create an air free environment in a pressurized pipe. Therefore, it is essential to understand the air transport in enclosed pipes in order to provide guidance in bottom outlet design and operation. The commonly used...

  15. Evolution of karst conduit networks in transition from pressurized flow to free-surface flow

    Science.gov (United States)

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

    2014-11-01

    Most of the existing models of speleogenesis are limited to situations where flow in all conduits is pressurized. The feedback between the distribution of hydraulic head and growth of new solution conduits determines the geometry of the resulting conduit network. We present a novel modeling approach that allows a transition from pressurized (pipe) flow to a free-surface (open-channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolution enlargement within each time step and steps through time until a stable flow pattern is established. The flow in each time step is calculated by calling the US Environmental Protection Agency Storm Water Management Model (US Environmental Protection Agency, 2014), which efficiently solves the 1-D Saint-Venant equations in a network of conduits. Two basic scenarios are modeled, a low-dip scenario and a high-dip scenario. In the low-dip scenario a slightly inclined plane is populated with a rectangular grid of solution conduits. The recharge is distributed to randomly selected junctions. The results for the pressurized flow regime resemble those of the existing models. When the network becomes vadose, a stable flow pathway develops along a system of conduits that occupy the lowest positions at their inlet junctions. This depends on the initial diameter and inlet position of a conduit, its total incision in a pressurized regime and its alignment relative to the dip of the plane, which plays important role during the vadose entrenchment. In the high-dip scenario a sub-vertical network with recharge on the top and outflow on the side is modeled. It is used to demonstrate the vertical development of karst due to drawdown of the water table, development of invasion vadose caves during vadose flow diversion and to demonstrate the potential importance of deeply penetrating conductive structures.

  16. Fracture Toughness Measurements and Assessment of Thin Walled Conduit Alloys in a Cicc Application

    Science.gov (United States)

    Walsh, R. P.; Han, K.; Toplosky, V. J.

    2008-03-01

    The Series-Connected Hybrid Magnets under construction at the NHMFL use Cable-in-Conduct-Conductor (CICC) technology. The 4 K mechanical properties of the conduit are extremely important to the performance and reliability of the magnets. We have measured tensile and fracture toughness of two candidate conduit alloys (Haynes 242 and modified 316LN) in various metallurgical states, with emphasis on the final state of production. To assess the material in its final production state, non-standard specimens are removed directly from the round-corner rectangular conduit and tested after exposure to a simulated Nb3Sn reaction heat treatment. Non-standard middle-tension (MT) fracture toughness specimens enable toughness evaluation of the base metal, welds and weld/base transitional region in the as-fabricated conduit with final dimensions not suitable for conventional fracture toughness specimens. Although fracture toughness tests of the thin walled conduit fail to meet ASTM test validity requirements they provide a qualitative evaluation and estimate of the fracture toughness of the conduit and the welds.

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

    Science.gov (United States)

    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.

  18. In Vitro Evaluation of Carbon-Nanotube-Reinforced Bioprintable Vascular Conduits

    Science.gov (United States)

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

    2014-01-01

    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 (HCASMCs) 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. PMID:24632802

  19. A nerve guidance conduit with topographical and biochemical cues: potential application using human neural stem cells

    Science.gov (United States)

    Jenkins, Phillip M.; Laughter, Melissa R.; Lee, David J.; Lee, Young M.; Freed, Curt R.; Park, Daewon

    2015-06-01

    Despite major advances in the pathophysiological understanding of peripheral nerve damage, the treatment of nerve injuries still remains an unmet medical need. Nerve guidance conduits present a promising treatment option by providing a growth-permissive environment that 1) promotes neuronal cell survival and axon growth and 2) directs axonal extension. To this end, we designed an electrospun nerve guidance conduit using a blend of polyurea and poly-caprolactone with both biochemical and topographical cues. Biochemical cues were integrated into the conduit by functionalizing the polyurea with RGD to improve cell attachment. Topographical cues that resemble natural nerve tissue were incorporated by introducing intraluminal microchannels aligned with nanofibers. We determined that electrospinning the polymer solution across a two electrode system with dissolvable sucrose fibers produced a polymer conduit with the appropriate biomimetic properties. Human neural stem cells were cultured on the conduit to evaluate its ability to promote neuronal growth and axonal extension. The nerve guidance conduit was shown to enhance cell survival, migration, and guide neurite extension.

  20. A nerve guidance conduit with topographical and biochemical cues: potential application using human neural stem cells.

    Science.gov (United States)

    Jenkins, Phillip M; Laughter, Melissa R; Lee, David J; Lee, Young M; Freed, Curt R; Park, Daewon

    2015-12-01

    Despite major advances in the pathophysiological understanding of peripheral nerve damage, the treatment of nerve injuries still remains an unmet medical need. Nerve guidance conduits present a promising treatment option by providing a growth-permissive environment that 1) promotes neuronal cell survival and axon growth and 2) directs axonal extension. To this end, we designed an electrospun nerve guidance conduit using a blend of polyurea and poly-caprolactone with both biochemical and topographical cues. Biochemical cues were integrated into the conduit by functionalizing the polyurea with RGD to improve cell attachment. Topographical cues that resemble natural nerve tissue were incorporated by introducing intraluminal microchannels aligned with nanofibers. We determined that electrospinning the polymer solution across a two electrode system with dissolvable sucrose fibers produced a polymer conduit with the appropriate biomimetic properties. Human neural stem cells were cultured on the conduit to evaluate its ability to promote neuronal growth and axonal extension. The nerve guidance conduit was shown to enhance cell survival, migration, and guide neurite extension. PMID:26071111

  1. Current distribution in Cable-In-Conduit Conductors

    International Nuclear Information System (INIS)

    A numerical study of the current distribution in Cable-In-Conduit Conductors (CICC's) experiencing linearly ramping transport currents and transverse magnetic fields was conducted for both infinitely long, periodic cables and finite length cables terminated in low resistance joints. The goal of the study was to gain insight into the phenomenon known as Ramp Rate Limitation, an as yet unexplained correspondence between maximum attainable current and the ramp time taken to reach that current in CICC superconducting magnets. A discrete geometric model of a 27 strand multiply twisted CICC was developed to effectively represent the flux linkages, mutual inductances, and resistive contact points between the strands of an experimentally tested cable. The results of the numerical study showed that for fully periodic cables, the current imbalances due to ramping magnetic fields and ramping transport currents are negligible in the range of experimentally explored operating conditions. For finite length, joint terminated cables, however, significant imbalances can exist. Unfortunately, quantitative results are limited by a lack of knowledge of the transverse resistance between strands in the joints. Nonetheless, general results are presented showing the dependency of the imbalance on cable length, ramp time, and joint resistance for both ramping transverse magnet fields and ramping transport currents. At the conclusion of the study, it is suggested that calculated current imbalances in a finite length cable could cause certain strands to prematurely ''quench'' -- become non-superconducting --thus leading to an instability for the entire cable. This numerically predicted ''current imbalance instability'' is compared to the experimentally observed Ramp Rate Limitation for the 27 strand CICC sample

  2. Method and means for disposal of radioactive waste

    International Nuclear Information System (INIS)

    A method is described for processing radioactive waste material which is to be isolated from the environment as the waste material is received from a source thereof and introduced into a container for disposal consisting of: (a) providing enclosure means adapted to receive the container and conduit means adapted to convey the material from the source into the container with the enclosure; (b) disposing container in enclosure; closing the enclosure to isolate the container from the environment and sealing the container; (c) detachably connecting the container and conduit with a fluidtight seal within the enclosure to isolate the interior region of the container from the interior region of the enclosure; (d) providing a positive gas pressure difference between the interior regions of the enclosure and container and monitoring the gas pressure difference to verify the integrity of the fluidtight seal between the container and conduit means; and, upon positive verification (e) conveying the material through the conduit means and into the container for disposal

  3. Méthodes de calcul des écoulements diphasiques pétroliers dans les conduites Methods for Calculating Two-Phase Flow in Pipes

    Directory of Open Access Journals (Sweden)

    Fitremann J. -M.

    2006-11-01

    Full Text Available Dans une première partie sont définies les principales grandeurs statistiques employées dans le calcul des grandeurs physiques moyennes des écoulements diphaslques en conduites. Les équations moyennées soit sur une section, soit statistiquement, soit doublement moyennées sont décrites ensuite afin de montrer, à l'aide de trois exemples : calcul des écoulements annulaires, calcul des écoulements par bouchons et calcul de modes de propagation d'ondes, les procédés et difficultés de calcul des grandeurs associés à ces écoulements. The first part of this article defines the leading statistical magnitudes used for calculating the mean physical magnitudes of two-phase flows in pipes. The equations are averaged on either a section or statistically, or else they are doubly averaged. They are described for the purpose of explaining the processes and difficulties of calculating magnitudes associated with flows. For this, the following three examples are used calculating annular flows, calculating slug flows, and calculating wave-propagation systems.

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

    Directory of Open Access Journals (Sweden)

    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 penetration of high hydraulic head and give rise to high gradients and possible fast evolution of conduit systems deep within the massif.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Fabrication and Optimization of Gelatin/ Nano Bioglass Conduits for Peripheral Nerve Regeneration

    Directory of Open Access Journals (Sweden)

    M. Foroutan Koudehi

    2014-07-01

    Full Text Available Introduction & Objective: Peripheral nerve injury is common in trauma patients and 4.5% of all soft-tissue injuries are accompanied by defects of peripheral nerve. Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Designed conduits com-prised of natural and synthetic materials are now widely used in the construction of damaged tissues. The aim of this project was to prepare nanocomposite conduits from gelatin and bioglass for damaged peripheral nerve reconstruction. Materials & Methods: In this experimental study,compound water solution of gelatin and nano bioglass synthesized through sol gel method, was made. After preparing the solution, special mandrels were dipped in solution several times and freeze dried in order to be emptied of wa-ter via sublimation. The conduits had the following dimensions: internal diameter: 1.6 mm, outside diameter: 2.2 mm and length about 12 mm. In order to evaluate the biocompatibility of conduits we used cytotoxicity test by Chinese ovary cells and MTT assay by Miapaca-2 (pancreatic cancer cell line. Results: The prepared nano bioglass and conduits were characterized using transmission elec-tron microscopy, scanning electron microscopy, fourier transformed infrared spectroscopy and X-ray diffraction. Results of biocompatibility test showed no sign of cytotoxicity and cells were found to be attached to the pore walls offered by the conduits. Conclusion: According to the results, nano bioglass conduits could be a good candidate for peripheral nerve regeneration. (Sci J Hamadan Univ Med Sci 2014; 21 (2:152-160

  7. Numerical simulation of the flow in a conduit, in the presence of a confined air cushion

    Science.gov (United States)

    Nguyen, Trieu Dong

    1999-02-01

    A rectangular conduit with a closed end has water flowing in/out at the other end. The water level at the open end has an imposed sinusoidal movement. When this level is higher than the ceiling of the conduit, a certain mass of air is trapped under the ceiling. In a previous article (T.D. Nguyen, La Houille Blanche, No. 2, 1990), it was supposed that this air is flowing out freely through the ceiling, so the relative pressure at the water surface is zero, and the water hammer at the dead end of the conduit was calculated when the conduit was thoroughly filled. In this article, it is supposed that the trapped air is compressed isothermally or adiabatically. The set of equations is resolved (water continuity and movement equations, air state equation) by supposing a regime of flow at each section (section submerged or not), a certain value for the air pressure and by using the sweep method to determine the water flow characteristics. The air volume calculated by iteration must converge, and the calculated regimes at each section (submerged or free) must agree with the supposed regimes. The simulation is performed first with a horizontal conduit then with an inclined conduit. As expected, adiabatic compression gives higher pressure than isothermal compression. The simulation shows also that when there is an air cushion, compared with the case when air is flowing out freely, the shock of the water hammer at the closed end of the conduit is significantly reduced. This method is aimed at calculating the flow with entrapped air in the inlet/outlet tunnel of a hydroelectric plant, or in sewer system pipe when a sudden discharge surge (due to turbin opening/closing or to urban storm) changes a previously free-surface flow in a mostly full-pipe flow, but with some air entrapped under the ceiling. Copyright

  8. Visualization of conduit-matrix conductivity differences in a karst aquifer using time-lapse electrical resistivity

    Science.gov (United States)

    Meyerhoff, Steven B.; Karaoulis, Marios; Fiebig, Florian; Maxwell, Reed M.; Revil, André; Martin, Jonathan B.; Graham, Wendy D.

    2012-12-01

    In the karstic upper Floridan aquifer, surface water flows into conduits of the groundwater system and may exchange with water in the aquifer matrix. This exchange has been hypothesized to occur based on differences in discharge at the Santa Fe River Sink-Rise system, north central Florida, but has yet to be visualized using any geophysical techniques. Using electrical resistivity tomography, we conducted a time-lapse study at two locations with mapped conduits connecting the Santa Fe River Sink to the Santa Fe River Rise to study changes of electrical conductivity during times of varying discharge over a six-week period. Our results show conductivity differences between matrix, conduit changes in resistivity occurring through time at the locations of mapped karst conduits, and changes in electrical conductivity during rainfall infiltration. These observations provide insight into time scales and matrix conduit conductivity differences, illustrating how surface water flow recharged to conduits may flow in a groundwater system in a karst aquifer.

  9. Magma compaction, gas exsolution and decompression in volcanic conduits

    Science.gov (United States)

    Michaut, Chloé; Ricard, Yanick; Bercovici, David

    2010-05-01

    Gas content, exsolution and segregation from magma strongly influences the dynamics of a volcanic eruption. Recently, magma compaction has been shown to exert a control on gas content and segregation in viscous silicic magmas (Michaut et al, 2009). Dynamics of magma and gas mixtures in volcanic conduit are often studied using homogeneous models, where both phases move at the same velocity, or two-phase flow models, where both phases are at the same pressure, hence where no compaction occurs. We extend the two-phase flow theory of Bercovici and Ricard (2003) to take into account gas exsolution from magma matrix as well as gas compressibility. Gas solubility is considered to be a function of gas pressure only. The gas is considered perfect and is in the form of bubbles; the drag between phases follows Stoke's law, assuming a constant number of bubbles. We identify two dimensionless numbers: the first one characterizes the viscous resistance to flow and compaction; the second one characterizes the drag between phases. We compare the results of steady-state two-phase flow models with two limiting cases: homogeneous flow and single-pressure two-phase flow. Starting with negligible amount of gas in magma, gas exsolution and decompression occur over a characteristic distance that increases with the viscous resistance parameter. The compaction term is maximum at the beginning, and, as gas exsolves, it is rapidly expelled by compaction, resulting in a smaller increase in gas content with height in comparison with a single-pressure flow. The difference becomes negligible as viscosity and velocity decrease and initial gas pressure increases. As the amplitude of the inter-phase drag decreases, gas also expels more rapidly at first, but gas decompression and exsolution are more rapid and the characteristic distance over which they occur decreases. At steady-state and for a given surface pressure, taking into account both compaction and inter-phase drag favors gas escape and leads to less gas content at the exit than in the homogeneous or single-pressure models, and thus requires a larger original volatile content for explosive eruptions.

  10. Piezoelectric trace vapor calibrator

    Science.gov (United States)

    Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

    2006-08-01

    The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10°C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver—on demand—continuous vapor concentrations across more than six orders of magnitude (nominally 290fg/lto1.05?g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

  11. Piezoelectric trace vapor calibrator

    International Nuclear Information System (INIS)

    The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 ?g/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlIMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process

  12. Electrospun polycaprolactone/polylactic acid nanofibers as an artificial nerve conduit

    International Nuclear Information System (INIS)

    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 55-65 m. 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. (author)

  13. AMTEC vapor-vapor series connected cells

    Science.gov (United States)

    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.

  14. Vaporization of ThC and (Th,U)C

    International Nuclear Information System (INIS)

    Vaporization behavior of thorium carbide fuels, ThC and (Th,U)C, was studied by high temperature mass spectrometry. Both ThC and (Th,U)C were prepared by carbothermic reduction. Vapor pressure of U(g) or, U(g) and Th(g) was measured by using a graphite-linered tantalum Knudsen cell. Besides the absolute vapor pressure, the partial molal enthalpy of vaporization and the partial molar Gibbs energy of Th were evaluated for ThC1±x. For (Th,U)C, activities of ThC and UC in addition to absolute vapor pressures were evaluated. Then, compatibility of ThC with either Ni, Fe or Cr was examined by means of an EPMA analysis of the reaction zone. Only Ni showed significant reaction with ThC. Three reaction layers were identified. Finally, preparation of high density ThC pellet by means of sintering was studied. (author)

  15. Biodegradable Conduit Small Gap Tubulization for Peripheral Nerve Mutilation: A Substitute for Traditional Epineurial Neurorrhaphy

    Directory of Open Access Journals (Sweden)

    Peixun Zhang, Na Han, Tianbing Wang, Feng Xue, Yuhui Kou, Yanhua Wang, Xiaofeng Yin, Laijin Lu, Guanglei Tian, Xu Gong, Shanlin Chen, Yu Dang, Jianping Peng, Baoguo Jiang

    2013-01-01

    Full Text Available Nerve regeneration and re-innervation are usually difficult after peripheral nerve injury. Epineurium neurorrhaphy to recover the nerve continuity is the traditional choice of peripheral nerve mutilation without nerve defects, whereas the functional recovery remains quite unsatisfactory. Based on previous research in SD rats and Rhesus Monkeys, a multiple centers clinical trial about biodegradable conduit small gap tubulization for peripheral nerve mutilation to substitute traditional epineurial neurorrhaphy was carried out. Herein, the authors reviewed the literature that focused on peripheral nerve injury and possible clinical application, and confirmed the clinical possibilities of biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation. The biodegradable conduit small gap tubulization to substitute traditional epineurial neurorrhaphy for peripheral nerve mutilation may be a revolutionary innovation in peripheral nerve injury and repair field.

  16. Descent of low-Bond-number liquid-metal diapirs with trailing conduits during core formation

    Science.gov (United States)

    Rains, C.; Weeraratne, D. S.

    2012-12-01

    Formation of the early Earth involved violent impacts and meteorite bombardment which partially or fully melted surface materials, facilitating separation of iron metal from silicates. Geochemical constraints on core formation times indicate that this liquid metal must have been transported to the center of the Earth within 30 Ma. Among the mechanisms that have been proposed, metal-silicate plumes resulting from Rayleigh-Taylor instabilities of a liquid-metal pond at the bottom of a magma ocean provide the fastest rates of delivery to the core. Recent studies have shown that these rapidly descending plumes develop trailing conduits that fill with the overlying melted silicate material. However, while large plumes descend quickly, they do not provide enough time or surface area for metal-silicate equilibration to be achieved throughout the mantle. Instead, small metal drops descending in the wake of larger diapirs or in conduits of their own making may have been crucial in the equilibration process that resulted in the excess siderophile mantle abundance. We investigate the instability and descent of liquid-metal drops through a highly viscous layer using three-component laboratory fluid experiments representing the Earth's proto-mantle (layer 2) covered by a magma ocean (layer 1), and a liquid iron pond (layer 3) initially resting at their interface. Silicate materials are represented by dehydrated (layer 2), or diluted (layer 1) glucose and salt solutions. Liquid gallium represents the iron metal phase. We scale our experiments to the Earth's mantle through the use of Bond numbers to characterize drops and diapirs, and a non-dimensional length scale ?, which we define as the ratio of radius to height, to characterize conduits. Previous laboratory work using liquid gallium has investigated high-Bond-number diapirs (B = 13 - 66) and conduits of ? ~ 0.2, analogous to large plumes in the Earth. Here, we focus on low Bond numbers (B ~ 4), and small ? ~ .05 to consider small metal drops followed by long, thin conduits. We describe the density and viscosity conditions under which trailing conduits open behind metal drops, and the resulting conduit geometry and drop shapes. We find that the descent times of metal drops, morphology of plumes, and relaxation times of conduits in tri-fluid systems depend strongly on the density ratio between the overlying magma ocean and the mantle material as well as the viscosity of the mantle. Only under conditions of high density ratios and high mantle viscosity will long conduits form behind sinking metal drops. These conduits entrain magma-ocean material to the base of the mantle, with return flow occurring via solitons that travel upward along the original conduit path. We also find that the presence of an intermediate diffusion layer between fluids 1 and 2, analogous to a crystal mush on the bottom of a partially-solidified magma ocean, significantly decreases onset times of the R-T instability. Thus, in the case of large mantle viscosities and sufficiently high buoyancy ratios, trailing conduits entrained by sinking metal drops provide a valid mechanism for metal-silicate equilibration in the deep mantle while rapidly delivering iron to the core.

  17. Radiation response of optical fibers encased in a radiation resistant telecommunications conduit

    International Nuclear Information System (INIS)

    The results of exposing two multimode silica core optical fibers to Co-60 gamma irradiation in a radiation shielded configuration is presented. The fibers were operated at a wavelength of 850 nm during the irradiations. The radiation exposure consisted of dose rates at the fibers ranging from 59.6 rad(Si)/min to 92.2 rad(Si)/min within the radiation resistant conduit (RRC) and plastic conduit, respectively. It was observed that the fiber within the RRC experienced approximately 8.0 dB/km less radiation induced attenuation than the fiber within the plastic conduit with identical external radiation exposure and geometries. The measurements were performed at room temperature (T = 21.5 C) using well defined, highly stable optical sources and detectors. 9 refs

  18. Investigation of a Nb-Ti cable-in-conduit conductor: experimental results

    International Nuclear Information System (INIS)

    A NbTi, Cable-in-conduit sample coil was experimentally investigated by using inductive heat inputs of durations 0.44 and 2.1 msec. Since the original goal of determining the effect of varying conductor perimeter on stability could not be achieved, the stability parameters which were studied and reported include mass flow rate, heating duration, and the presence of liquid helium outside of the conduit versus a surrounding vacuum. In addition, quench-induced pressure rises, both at zero and non-zero imposed flow rates, were measured. Results indicate that stability increases with imposed mass flow, stability increases with heating duration before the limiting current, and helium outside of the conduit has no discernible effect on transient stability. A detailed analysis of these findings will be published in the future. (author)

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

    Directory of Open Access Journals (Sweden)

    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 regeneration was found with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel grafts than with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells grafts and the autologous nerve grafts.

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

    Science.gov (United States)

    Wang, Yang; Li, Zheng-Wei; Luo, Min; Li, Ya-Jun; Zhang, Ke-Qiang

    2015-06-01

    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 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 regeneration was found with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel grafts than with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells grafts and the autologous nerve grafts. PMID:26199615

  1. Wave Propagation in Axi-Symmetrical Magmatic Conduits Due to an Internal Source

    Science.gov (United States)

    De Negri, R. S.; Sanchez-Sesma, F. J.; Arciniega-Ceballos, A.

    2014-12-01

    The classical Trefftz's method is implemented to simulate wave propagation in and around axi-symmetrical magmatic conduits. In this fluid-solid system the fluid (magma) is confined by an elastic unbounded medium that represents the surrounding rock. Our aim is to associate wave behavior with mechanical and geometrical conduit characteristics. The source is assumed to be at a point along the conduit centered axis medium are constructed in both cases as linear combinations of particular solutions.Within the fluid such solutions are spherical standing waves that are smooth at the origins. In the elastic solid region the field is constructed with monopoles and dipoles for the P waves and spheroidal dipoles for SV waves. The particular solutions satisfy the elastodynamic equations that govern the wave motion at those media and are associated to origins (selected points) distributed along the conduit axis. For the surrounding rock the solutions are sources that satisfy Sommerfeld's radiation condition. These sets of solutions are assumed to be complete. This conjecture is exact in 2D acoustic problems. The conduit can be closed or open at the ends and the surrounding elastic domain is unbounded. In order to find the coefficients of Trefftz's wave expansions, boundary conditions at the fluid-solid interface (null shear and continuity of pressures and normal velocities) are satisfied in the least squares sense. The solution is obtained in the frequency domain and the source time function can be introduced using Fourier analysis.Regardless the low order of the formulation our results display a rich variety of behaviors. For a uniform infinite cylinder we reproduced the exact analytical solution. In addition, this approach allows identifying some important effects of the conduit geometry, including changes of sections. Lateral and longitudinal resonances of irregular axi-symmetric conduits are well resolved. The stiffness of the solid domain with respect to the fluid compressibility is explored regarding the effects of changing fluid and solid properties. Our analytical approach can be useful to understand volcanic conduit dynamics from the interpretation of the observed seismic wave field.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Monolithic microwave integrated circuit water vapor radiometer

    Science.gov (United States)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  5. In vivo studies of silk based gold nano-composite conduits for functional peripheral nerve regeneration.

    Science.gov (United States)

    Das, Suradip; Sharma, Manav; Saharia, Dhiren; Sarma, Kushal Konwar; Sarma, Monalisa Goswami; Borthakur, Bibhuti Bhusan; Bora, Utpal

    2015-09-01

    We report a novel silk-gold nanocomposite based nerve conduit successfully tested in a neurotmesis grade sciatic nerve injury model in rats over a period of eighteen months. The conduit was fabricated by adsorbing gold nanoparticles onto silk fibres and transforming them into a nanocomposite sheet by electrospinning which is finally given a tubular structure by rolling on a stainless steel mandrel of chosen diameter. The conduits were found to promote adhesion and proliferation of Schwann cells in vitro and did not elicit any toxic or immunogenic responses in vivo. We also report for the first time, the monitoring of muscular regeneration post nerve conduit implantation by recording motor unit potentials (MUPs) through needle electromyogram. Pre-seeding the conduits with Schwann cells enhanced myelination of the regenerated tissue. Histo-morphometric and electrophysiological studies proved that the nanocomposite based conduits pre-seeded with Schwann cells performed best in terms of structural and functional regeneration of severed sciatic nerves. The near normal values of nerve conduction velocity (50 m/sec), compound muscle action potential (29.7 mV) and motor unit potential (133 ?V) exhibited by the animals implanted with Schwann cell loaded nerve conduits in the present study are superior to those observed in previous reports with synthetic materials as well as collagen based nerve conduits. Animals in this group were also able to perform complex locomotory activities like stretching and jumping with excellent sciatic function index (SFI) and led a normal life. PMID:26026910

  6. Inference of the structure of karst conduits using quantitative tracer tests and geological information: example of the Swiss Jura

    Science.gov (United States)

    Perrin, Jérôme; Luetscher, Marc

    2008-08-01

    Karst aquifers are known for being particularly heterogeneous with highly transmissive conduits embedded in low permeability volumes of rock matrix. Artificial tracer experiments have been carried out in a complex karst aquifer of the folded Jura Mountains in Switzerland with the aim of deciphering the conduit organisation. It is shown that tracer experiments with multiple injection points under different flow conditions can lead to useful information on the conduits’ structure. This information has been combined with data from structural geology, spring hydrology, and speleological observations. A conceptual model of the conduit network shows that a detailed inference of the conduit organisation can be reached: geology controls conduit location and orientation; spring hydrology, including temporary springs, constrains conduit elevations and relative hydraulic heads in the aquifer subsystems; and tracer tests identify major flow paths and outlets of the system and dilution caused by non-traced tributaries, as well as the presence of secondary flow routes. This understanding of the Aubonne aquifer structure has important implications for the future management of the groundwater resource. Similar approaches coupling geological information, spring hydrology, and multi-tracer tests under various flow conditions may help to characterise the structure of the conduit network in karst aquifers.

  7. Reconstrução arterial com tubo de pericárdio bovino corrugado / Arterial reconstruction with crimped bovine pericardial conduit

    Scientific Electronic Library Online (English)

    Cláudio A, Salles; Nilzo A. M, Ribeiro; Renato A. K, Kalil; Gilberto Lino, Vieira; Liberato S. S, Souza; Paulo M, Borém; Miguel E. C, Andrade; Rogério D, Faleiros; Marcos A. M, Andrade Jr.

    1992-06-01

    Full Text Available No período de agosto de 1989 a fevereiro de 1992, 32 pacientes foram submetidos a reconstruções vasculares utilizando-se condutos de pericárdio bovino corrugado preservado em glutaraldeído. A incorporação do principio crimping utilizado nas próteses vasculares sintéticas proporcionou tubos que mantê [...] m sua forma cilíndrica, mesmo quando submetidos a curvaturas. Vinte e nove pacientes (Grupo I) eram portadores de doenças da aorta torácica e/ou abdominal, incluindo aneurismas, dissecções agudas, coarctação da aorta e lesão oclusiva aorto-ilíaca. A reconstrução da aorta torácica foi realizada em 25 pacientes (incluindo a substituição da valva aórtica em 10), da aorta abdominal em 2 e aorto-ilíaca em 2. Três pacientes (Grupo II), portadores de cardiopatias congênitas complexas, foram submetidos a reconstrução da via de saída do ventrículo direito em 2 e a operação de Fontan em 1. A mortalidade hospitalar no Grupo I foi 24% (7 pacientes), causada por baixo débito cardíaco em 4, recidiva precoce da dissecção em dois e infecção respiratória em 1. Seis destes óbitos ocorreram em pacientes operados na fase aguda de dissecção aórtica. Não houve nenhum óbito no Grupo II. Houve um óbito tardio no Grupo I devido a complicações metabólicas relacionadas a diabetes e insuficiência renal crônica. Esta experiência clínica inicial registrou um seguimento médico de 16 meses por paciente, com um máximo de 32 meses e não se verificou nenhuma complicação tardia relacionada ao conduto de pericárdio bovino corrugado. Abstract in english From August 1989 to February 1992, 32 patients underwent vascular reconstructions using crimped bovine pericardial conduits processed in glutaraldehyde. The introduction of the crimping process used for synthetic vascular prosthesis provided circular tubes, which retain their shape with bending and [...] avoid kinking. Twenty-nine patients (Group I) presented vascular lesions involving the thoracic and/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.

  8. Reconstrução arterial com tubo de pericárdio bovino corrugado Arterial reconstruction with crimped bovine pericardial conduit

    Directory of Open Access Journals (Sweden)

    Cláudio A Salles

    1992-06-01

    Full Text Available No período de agosto de 1989 a fevereiro de 1992, 32 pacientes foram submetidos a reconstruções vasculares utilizando-se condutos de pericárdio bovino corrugado preservado em glutaraldeído. A incorporação do principio crimping utilizado nas próteses vasculares sintéticas proporcionou tubos que mantêm sua forma cilíndrica, mesmo quando submetidos a curvaturas. Vinte e nove pacientes (Grupo I eram portadores de doenças da aorta torácica e/ou abdominal, incluindo aneurismas, dissecções agudas, coarctação da aorta e lesão oclusiva aorto-ilíaca. A reconstrução da aorta torácica foi realizada em 25 pacientes (incluindo a substituição da valva aórtica em 10, da aorta abdominal em 2 e aorto-ilíaca em 2. Três pacientes (Grupo II, portadores de cardiopatias congênitas complexas, foram submetidos a reconstrução da via de saída do ventrículo direito em 2 e a operação de Fontan em 1. A mortalidade hospitalar no Grupo I foi 24% (7 pacientes, causada por baixo débito cardíaco em 4, recidiva precoce da dissecção em dois e infecção respiratória em 1. Seis destes óbitos ocorreram em pacientes operados na fase aguda de dissecção aórtica. Não houve nenhum óbito no Grupo II. Houve um óbito tardio no Grupo I devido a complicações metabólicas relacionadas a diabetes e insuficiência renal crônica. Esta experiência clínica inicial registrou um seguimento médico de 16 meses por paciente, com um máximo de 32 meses e não se verificou nenhuma complicação tardia relacionada ao conduto de pericárdio bovino corrugado.From August 1989 to February 1992, 32 patients underwent vascular reconstructions using crimped bovine pericardial conduits processed in glutaraldehyde. The introduction of the crimping process used for synthetic vascular prosthesis provided circular tubes, which retain their shape with bending and avoid kinking. Twenty-nine patients (Group I presented vascular lesions involving the thoracic and/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.

  9. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Vapor pressures and enthalpies of vaporization of azides

    International Nuclear Information System (INIS)

    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 ?lgHm 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.

  11. Vapor pumps and gas-driven machines

    International Nuclear Information System (INIS)

    The vapor pump, patented in 1979 by Gaz de France, is an additional mass and heat exchanger which uses the combustion air of fuel-burning machines as an additional cold source. This cold source is preheated and, above all, humidified before reaching the burner, by means of the residual sensible and latent heat in the combustion products of the fuel-burning process. This final exchanger thus makes it possible, in many cases, to recover all the gross calorific value of natural gas, even when the combustion products leave the process at a wet temperature greater than 600 C, the maximum dew point of the products of normal combustion. Another significant advantage of the vapor pump being worth highlighting is the selective recycling of water vapor by the vapor pump which reduces the adiabatic combustion temperature and the oxygen concentration in the combustion air, two factors which lead to considerable reductions in nitrogen oxides formation, hence limiting atmospheric pollution. Alongside a wide range of configurations which make advantageous use of the vapor pump in association with gas-driven machines and processes, including gas turbines, a number of boiler plant installations are also presented

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

    International Nuclear Information System (INIS)

    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 minresent 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 during the cooling process-from values typical for film boiling to much higher values typical for nucleate boiling. Correlations for the minimum temperature and the minimum heat flux necessary to maintain film boiling were established in terms of the subcooling level, the size of the spheres and their material. The minimum temperature to maintain film boiling was used as the principle criteria for the occurrence of vapor explosion. Other criteria, for the intensity of the vapor film collapse was derived from the maximum heat flux following the vapor film collapse, and the audible sound (which is generated by the shock wave). It is assumed that a high intensity of the vapor film collapse will result in a more efficient propagation stage and enhancement of the vapor explosion

  13. Jean Vigo's "Zéro De Conduite" and the Spaces of Revolt

    Science.gov (United States)

    Vanobbergen, Bruno; Grosvenor, Ian; Simon, Frank

    2014-01-01

    In this article we will contribute to the contemporary theoretical debate about film by considering, from a history-of-education perspective, the film "Zéro de conduite" by Jean Vigo (1905--1934). This film is classified under the umbrella of "poetic realism": a product of "cinéma de gauche" and an avant-gardist,…

  14. Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes.

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Svetlik, D.; Soukup, J.; Schweigstillová, Jana; Válek, Jan; Sedlá?ková, M.; Mayo, A.L.

    2012-01-01

    Ro?. 177, December (2012), s. 178-193. ISSN 0169-555X R&D Projects: GA AV ?R IAA300130806 Institutional support: RVO:67985891 ; RVO:68378297 Keywords : sandstone * erosion * piping * tensile strength * conduit * landform Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.552, year: 2012

  15. The formation of boundary waves in closed conduits with sediment transported

    Science.gov (United States)

    Hiratsuka, Tomofumi; Izumi, Norihiro

    There have been a large number of studies on bed waves in rivers. It has been known that bed waves are strongly related to the Froude number. Meanwhile, there are only few studies on waves formed at the boundary between flowing water and erodible beds in closed conduits without free water surfaces. In order to predict the flow resistance of closed conduits such as sediment bypass tunnels and ice-covered rivers, it is important to obtain detailed information on the formation of boundary waves. Seki and Izumi2) have proposed a linear stability analysis to explain the formation of small scale boundary waves in closed conduits. They have also reproduced small scale boundary waves in flume experiments, and compared with their analysis. According to their analysis, the Shields and Euler numbers are the dominant parameters, and the flat bed becomes unstable when the Euler number becomes larger than the critical Euler number, which increases with the Shields number. However, the agreement between the prediction and their observation is not sufficiently good. In this study, we introduce the ratio of the shear velocities between the lower and upper walls as a new parameter, and improve the agreement. In addition, we perform a weakly nonlinear stability analysis to obtain more detailed information on behavior of boundary waves in the vicinity of the critical Euler number. We find that the transition between flat bed and boundary wave regimes in closed conduits is characterized by subcritical bifurcation.

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

    LENUS (Irish Health Repository)

    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.

  17. Retrofitting shear stability and fixing clay soil in farm conduits by geotextiles

    International Nuclear Information System (INIS)

    Shear tests which conducted in the soil mechanics laboratory to determine the effects of polymer materials (geotextiles) on shear strength of reinforced clay in conduits. It was found that setting geo textile sheets in 60 degrees to the plane of failure increases shear strength to a maximum of 25% than that with an unreinforced clay. (author)

  18. Development of a new autonomous probe for in situ flow characterization in drowned subsurface conduits

    Science.gov (United States)

    Hakoun, V.; Pistre, S.; Falgayrettes, P.

    2013-12-01

    Groundwater flow in karst aquifers is influenced by the presence of self-organized networks of large conduits. Existing methods which use artificial tracers or tethered robots, provide a limited amount of information on the network's geometry, and on the flow regime that occurs in the conduits. To address hydrogeological problems relative to karst aquifers, the characterization of the flow conditions in the network of conduits is needed. However this is a challenging task. We present a novel wireless probe which is developed to allow remote characterization of main flow directions and regime in subsurface environments. The relatively small (40 mm diameter) spherical autonomous probe is designed to allow transport by the water stream. During its journey in the flow, the non-expensive electronic equipment installed on board measures and records orientation data. Once the probe is retrieved, the recorded measurements can be analyzed. The encouraging preliminary laboratory results indicate that the new probe can accurately characterize different flow directions and regimes. This new autonomous probe offers a chance to help address the challenging task of characterizing flow in unknown drowned karst conduits.

  19. Modifications to the Conduit Flow Process Mode 2 for MODFLOW-2005.

    Science.gov (United States)

    Reimann, Thomas; Birk, Steffen; Rehrl, Christoph; Shoemaker, W Barclay

    2012-01-01

    As a result of rock dissolution processes, karst aquifers exhibit highly conductive features such as caves and conduits. Within these structures, groundwater flow can become turbulent and therefore be described by nonlinear gradient functions. Some numerical groundwater flow models explicitly account for pipe hydraulics by coupling the continuum model with a pipe network that represents the conduit system. In contrast, the Conduit Flow Process Mode 2 (CFPM2) for MODFLOW-2005 approximates turbulent flow by reducing the hydraulic conductivity within the existing linear head gradient of the MODFLOW continuum model. This approach reduces the practical as well as numerical efforts for simulating turbulence. The original formulation was for large pore aquifers where the onset of turbulence is at low Reynolds numbers (1 to 100) and not for conduits or pipes. In addition, the existing code requires multiple time steps for convergence due to iterative adjustment of the hydraulic conductivity. Modifications to the existing CFPM2 were made by implementing a generalized power function with a user-defined exponent. This allows for matching turbulence in porous media or pipes and eliminates the time steps required for iterative adjustment of hydraulic conductivity. The modified CFPM2 successfully replicated simple benchmark test problems. PMID:21371024

  20. X-ray computed-tomography imaging of gas migration in water-saturated sediments: From capillary invasion to conduit opening

    Science.gov (United States)

    Choi, Jeong-Hoon; Seol, Yongkoo; Boswell, Ray; Juanes, Ruben

    2011-09-01

    The strong coupling between multiphase flow and sediment mechanics determines the spatial distribution and migration dynamics of gas percolating through liquid-filled soft granular media. Here, we investigate, by means of controlled experiments and computed tomography (CT) imaging, the preferential mode of gas migration in three-dimensional samples of water-saturated silica-sand and silica-silt sediments. Our experimental system allowed us to independently control radial and axial confining stresses and pore pressure while performing continuous x-ray CT scanning. The CT image analysis of the three-dimensional gas migration provides the first experimental confirmation that capillary invasion preferentially occurs in coarse-grained sediments whereas grain displacement and conduit openings are dominant in fine-grained sediments. Our findings allow us to rationalize prior field observations and pore-scale modeling results, and provide critical experimental evidence to explain the means by which conduits for the transit of methane gas may be established through the gas hydrate stability zone in oceanic sediments, and cause large episodic releases of carbon into the deep ocean.

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

    Science.gov (United States)

    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.

  2. The Development of the CONDUIT Advanced Control System Design and Evaluation Interface with a Case Study Application to an Advanced Fly by Wire Helicopter Design

    Science.gov (United States)

    Colbourne, Jason

    1999-01-01

    This report details the development and use of CONDUIT (Control Designer's Unified Interface). CONDUIT is a design tool created at Ames Research Center for the purpose of evaluating and optimizing aircraft control systems against handling qualities. Three detailed design problems addressing the RASCAL UH-60A Black Hawk are included in this report to show the application of CONDUIT to helicopter control system design.

  3. Muonium formation in vapors

    International Nuclear Information System (INIS)

    The fractions of positive muons thermalizing in vapors as either the muonium atom (fsub(M)) or in diamagnetic environments (fsub(D)) have been measured in water, methanol, hexane, c-hexane, the chlorinated methanes and in TMS, in the pressure range from approximately 0.1 to approximately 2.5 atm. There is a marked difference in every case in comparison with the corresponding fractions (Psub(M),Psub(D)) measured in condensed media, with approximately 80 percent of incident muons forming muonium in the vapor phase compared to approximately 20 percent in the corresponding condensed phases. CClsub(4) appears somewhat anomalous in that it shows an unusually small muonium fraction in the vapor (fsub(D) approximately fsub(M)=0.5) and an unusually large diamagnetic fraction in the liquid (Psub(D)=1.0); these results can be attributed to large hot atom cross sections extending to the thermal regime, manifest as a relatively fast thermal rate constant for Mu + CClsub(4) (ksub(MU)=(2.9+-0.8) x 10sup(8) Msup(-1) ssup(-1)). The vapor phase results can be understood in terms of a charge exchange/hot atom (ion) model, providing also a likely explanation for observed pressure dependent fsub(D)'s in hexane, c-hexane and TMS at low (<0.5 atm) pressures in terms of termolecular processes, in analogy with some hot tritium studies. In the condensed phase, however, the present vapor phase results indicate that hot atom reactions cannot account for more than about 30 percent of the much larger diamagnetic fractions seen, strongly suggesting therefore that radiation induced spur effects play a dominant role in determining thermal muon fractions in condensed media

  4. Vapor pressure and enthalpy of vaporization of aliphatic propanediamines

    International Nuclear Information System (INIS)

    Highlights: ? We measured vapor pressure of four aliphatic 1,3-diamines. ? Vaporization enthalpies at 298 K were derived. ? We examined consistency of new and available data in the literature. ? A group-contribution method for prediction was developed. - Abstract: Vapor pressures of four aliphatic propanediamines including N-methyl-1,3-propanediamine (MPDA), N,N-dimethyl-1,3-propanediamine (DMPDA), N,N-diethyl-1,3-propanediamine (DEPDA) and N,N,N?,N?-tetramethyl-1,3-propanediamine (4MPDA) were measured using the transpiration method. The vapor pressures developed in this work and reported in the literature were used to derive molar enthalpy of vaporization values at the reference temperature 298.15 K. An internal consistency check of the enthalpy of vaporization was performed for the aliphatic propanediamines studied in this work. A group-contribution method was developed for the validation and prediction vaporization enthalpies of amines and diamines.

  5. Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

    International Nuclear Information System (INIS)

    Highlights: ? We measured vapor pressure of diamines H2N-(CH2)n-NH2 with n = 3 to 12. ? Vaporization enthalpies at 298 K were derived. ? We examined consistency of new and available in the literature data. ? Enthalpies of vaporization show linear dependence on numbers n. ? Enthalpies of vaporization correlate linearly with Kovat's indices. - Abstract: Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic alkanediamines H2N-(CH2)n-NH2 with n = (3 to 12) have been determined using the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the alkanediamines with the number n and with the Kovat's indices has been found, proving the internal consistency of the measured data.

  6. Temporal instabilities in volcanic conduit flow due to internal gravity waves and non-equilibrium degassing

    Science.gov (United States)

    Karlstrom, L.; Dunham, E. M.

    2013-12-01

    Volcanic conduits are strongly stratified multiphase mixtures of magma, bubbles and crystals exhibiting vertical gradients in density and pressure that drive flow. We examine the behavior of perturbations to this stratification in a model of multiphase flow through a cylindrical conduit using analytic and numerical linear stability analysis. Magma is idealized as a mixture of gas and liquid phases, accounting for compressibility of both phases, viscosity of the mixture, and a finite exsolution time for mass exchange between the phases. Short time variations in conduit flow variables are characterized by three modes of wave motion. Two modes correspond to sound waves that travel up and down the conduit, while the third is an internal gravity wave arising from restoring forces due to differences in density. When perturbed downward, a fluid parcel in the stratified magma is surrounded by more dense fluid and feels an upward restoring force from buoyancy. That restoring force can be reduced by compression of the fluid parcel by the greater pressures at depth that act to increase its density. These three modes of wave motion are characterized by several competing timescales. The timescale for viscous damping ? D sets the decay time of flow perturbations and the damping of sound waves and internal gravity waves propagating through the magma. The timescale of gravity wave oscillation, ? G (inverse of buoyancy frequency N), measures adjustment of perturbations to density and pressure differences in the vertically stratified magma. Finally, a timescale for volatile diffusion ? V measures adjustment of the gas phase mass fraction to its equilibrium solubility value. We examine perturbations to a magmastatic base state and to a base state of steady flow. Initial analytic results with frozen coefficients for a magmastatic and vertically unbounded conduit suggest that when ? V > ? G and ? D > ? G, ? V, the base state is unstable to harmonic perturbations in flow pressure, flow velocity, mixture density and gas fraction occurring above the exsolution depth. It is the internal gravity wave mode that goes unstable, while the sound wave solutions remain damped. Non-equilibrium degassing (relaxation to equilibrium solubility of greater than ˜1 second) and density stratification are both necessary conditions for this instability to occur. For parameters appropriate for low viscosity basaltic magma, these unstable perturbations have periods of 10--30 sec, while unstable modes do not occur for more viscous silicic magmas unless volatile contents are low (less than ˜1 weight percent). We are currently extending these results to steady flow in finite length conduits via numerical linear stability analysis and exploring the feasibility of detecting short-time flow instabilities in long period seismic radiation.

  7. A method of gastric conduit elevation via the posterior mediastinal pathway in thoracoscopic subtotal esophagectomy

    Directory of Open Access Journals (Sweden)

    Hirahara Noriyuki

    2012-01-01

    Full Text Available Abstract Background Despite efforts to improve surgical techniques, serious complications still sometimes occur. Use of a physiological posterior mediastinal pathway has increased given advances such as automated anastomotic devices and a reduction in the incidence of anastomotic sufficiency. Until now the gastric conduit created has been protected by an echo probe cover and, sown to the ventral side of polyester tape placed through the abdomen to the neck, and then blindly elevated to the neck. We report on a new method of gastric conduit elevation. Methods Two 60-cm lengths polyester tape are ligated at both ends to form a loop. An echo probe cover of 10 cm in diameter and 50 cm in length is prepared and the tip cut off, forming a cylinder. The knots in the previously looped polyester tape are inserted into the echo probe cover. The looped polyester tape and echo probe cover is ligated with silk approximately 5 cm in front of the knots on both sides. After dissection is carried out according to practice, the previously crafted polyester tape is inserted into the chest cavity. One end of polyester tape is fixed to the distal esophageal stump with the clips, with the opposite end fixed to the proximal esophageal stump. The echo probe cover that connects the proximal esophagus and distal esophagus is monitored for the presence of creases along the long axis to ensure there are no twists in the echo probe cover. We carry out a laparoscopic-assisted perigastric lymph node dissection, make a small skin incision, and guide part of the thoracic esophagus and stomach outside the body. Either one of the two lengths of polyester tape is connected to the gastric conduit. By pulling up this length of polyester tape from the neck, the gastric conduit can pass through the echo probe cover and be elevated to the neck. Results No perioperative complications such as bleeding or difficulty of the gastric conduit elevation were recognized with this method. Conclusions This method is considered to serve as a useful technique for gastric conduit elevation.

  8. Effects of vertical distribution of water vapor and temperature on total column water vapor retrieval error

    Science.gov (United States)

    Sun, Jielun

    1993-01-01

    Results are presented of a test of the physically based total column water vapor retrieval algorithm of Wentz (1992) for sensitivity to realistic vertical distributions of temperature and water vapor. The ECMWF monthly averaged temperature and humidity fields are used to simulate the spatial pattern of systematic retrieval error of total column water vapor due to this sensitivity. The estimated systematic error is within 0.1 g/sq cm over about 70 percent of the global ocean area; systematic errors greater than 0.3 g/sq cm are expected to exist only over a few well-defined regions, about 3 percent of the global oceans, assuming that the global mean value is unbiased.

  9. Cold work study on a 316LN modified alloy for the ITER TF coil conduit

    Science.gov (United States)

    Walsh, Robert; Toplosky, V. J.; McRae, D. M.; Han, K.; Martovetsky, N. N.

    2012-06-01

    In cable-in-conduit conductor (CICC) magnets, such as the ITER TF coils, the conduit is the primary structural component. This function creates requirements for 4 K strength, toughness, fatigue crack resistance, and ductility after exposure to the superconductor's reaction heat treatment. The tensile ductility of a steel is a quality factor related to fatigue and fracture resistance that can be evaluated more economically with tensile tests rather than fatigue and fracture tests. Here we subject 316LN modified base metal and welds to a range of cold work from 0% to 20% and a subsequent Nb3Sn reaction heat treatment to evaluate the effects on the tensile properties. With the addition of cold work, the 4 K yield strength increases while tensile elongation decreases in both the base metal and weld. The results are compared to previously published data on the same alloy to evaluate the use of tensile ductility parameters as a materials qualification specification in magnet design.

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

    Science.gov (United States)

    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.

  11. Solving the flow fields in conduits and networks using energy minimization principle with simulated annealing

    CERN Document Server

    Sochi, Taha

    2014-01-01

    In this paper, we propose and test an intuitive assumption that the pressure field in single conduits and networks of interconnected conduits adjusts itself to minimize the total energy consumption required for transporting a specific quantity of fluid. We test this assumption by using linear flow models of Newtonian fluids transported through rigid tubes and networks in conjunction with a simulated annealing (SA) protocol to minimize the total energy cost. All the results confirm our hypothesis as the SA algorithm produces very close results to those obtained from the traditional deterministic methods of identifying the flow fields by solving a set of simultaneous equations based on the conservation principles. The same results apply to electric ohmic conductors and networks of interconnected ohmic conductors. Computational experiments conducted in this regard confirm this extension. Further studies are required to test the energy minimization hypothesis for the non-linear flow systems.

  12. Role of Co-Vapors in Vapor Deposition Polymerization

    Science.gov (United States)

    Lee, Ji Eun; Lee, Younghee; Ahn, Ki-Jin; Huh, Jinyoung; Shim, Hyeon Woo; Sampath, Gayathri; Im, Won Bin; Huh, Yang–Il; Yoon, Hyeonseok

    2015-02-01

    Polypyrrole (PPy)/cellulose (PPCL) composite papers were fabricated by vapor phase polymerization. Importantly, the vapor-phase deposition of PPy onto cellulose was assisted by employing different co-vapors namely methanol, ethanol, benzene, water, toluene and hexane, in addition to pyrrole. The resulting PPCL papers possessed high mechanical flexibility, large surface-to-volume ratio, and good redox properties. Their main properties were highly influenced by the nature of the co-vaporized solvent. The morphology and oxidation level of deposited PPy were tuned by employing co-vapors during the polymerization, which in turn led to change in the electrochemical properties of the PPCL papers. When methanol and ethanol were used as co-vapors, the conductivities of PPCL papers were found to have improved five times, which was likely due to the enhanced orientation of PPy chain by the polar co-vapors with high dipole moment. The specific capacitance of PPCL papers obtained using benzene, toluene, water and hexane co-vapors was higher than those of the others, which is attributed to the enlarged effective surface area of the electrode material. The results indicate that the judicious choice and combination of co-vapors in vapor-deposition polymerization (VDP) offers the possibility of tuning the morphological, electrical, and electrochemical properties of deposited conducting polymers.

  13. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  14. Enceladus' water vapor plume.

    Science.gov (United States)

    Hansen, Candice J; Esposito, L; Stewart, A I F; Colwell, J; Hendrix, A; Pryor, W; Shemansky, D; West, R

    2006-03-10

    The Cassini spacecraft flew close to Saturn's small moon Enceladus three times in 2005. Cassini's UltraViolet Imaging Spectrograph observed stellar occultations on two flybys and confirmed the existence, composition, and regionally confined nature of a water vapor plume in the south polar region of Enceladus. This plume provides an adequate amount of water to resupply losses from Saturn's E ring and to be the dominant source of the neutral OH and atomic oxygen that fill the Saturnian system. PMID:16527971

  15. Chemical vapor composites (CVC)

    OpenAIRE

    Reagan, P.

    1993-01-01

    The Chemical Vapor Composite, CVC®, process fabricates composite material by simply mixing particles (powders and or fibers) with CVD reactants which are transported and co-depositedo n a hot substrate. A key feature of the CVC process is the control provided by varing the density, geometry (aspect ratio) and composition of the entrained particles in the matrix material, during deposition. The process can fabricate composite components to net shape (± 0.013 mm) on a machined substrate in a ...

  16. Role of lymphatic vessels in tumor immunity: passive conduits or active participants?

    OpenAIRE

    Lund, Amanda W.; Swartz, M. A.

    2010-01-01

    Research in lymphatic biology and cancer immunology may soon intersect as emerging evidence implicates the lymphatics in the progression of chronic inflammation and autoimmunity as well as in tumor metastasis and immune escape. Like the blood vasculature, the lymphatic system comprises a highly dynamic conduit system that regulates fluid homeostasis, antigen transport and immune cell trafficking, which all play important roles in the progression and resolution of inflammation, autoimmune dise...

  17. Possible conduit-matrix water exchange signatures outlined at a karst spring.

    Science.gov (United States)

    Mitrofan, Horia; Marin, Constantin; Povar?, Ioan

    2015-04-01

    During a significant flood event, reversible water exchanges may occur between a karst conduit and its adjacent porous rock (frequently designated as "matrix"): while the flood pulse rises, some conduit-derived water is forced into the matrix; then, as the flood recedes, the same water flows back into the stream passage. The present note addresses such a karst setting in the Carpathian Mountains (Romania), where in addition, a usually stable flux of chloride originating in a natural saline inflow, was being mixed with a variable flow of karst freshwater. For that particular case, with the above-mentioned process of matrix storage/release from storage assumedly taking place downstream of the mixing site, two distinct chemical signatures could be noticed during a flood event: an initial depletion in the spring flow chloride flux, subsequently followed by a comparable chloride flux enrichment (the depletion and the enrichment being outlined with respect to the essentially stable chloride flux value that had been noticed to persist at the spring over a long period of flow rate recession). Concomitantly with such flood-induced fluctuations in the spring chloride flux, the spring discharge displayed, for long periods, abnormally slow variations: the latter likely indicated that the spring supply rate actual oscillations were buffered by the reversible water exchanges which took place between the karst conduit and its adjacent matrix. On the whole, these results show that conduit-matrix water exchanges could be interpreted by simple mass balance calculations that involved fluxes of a conservative tracer (the chloride ion in that particular case). PMID:25394224

  18. Preliminary Experience with GORE-TEX® Grafting for Right Ventricle-Pulmonary Artery Conduits

    OpenAIRE

    Molina, J. Ernesto

    1986-01-01

    A consecutive series of 12 patients between the ages of 6½ and 37 years underwent implantation of venous ventricle-pulmonary artery conduits. GORE-TEX material without prosthetic valves was used. Four patients had L-transposition of the great vessels with ventricular septal defect (VSD) and pulmonary stenosis; four had tetralogy of Fallot with pulmonary atresia; and one had double outlet right ventricle, pulmonary stenosis, and a complete form of A-V canal. Two patients had D-transposition o...

  19. In vitro biocompatibility testing of some synthetic polymers used for the achievement of nervous conduits

    OpenAIRE

    Mihai, R; Florescu, IP; Coroiu, V; A. Oancea; Lungu, M.

    2011-01-01

    Biocompatible synthetic polymers are largely used in the bio–medical domain, tissue engineering and in controlled release of medicines. Polymers can be used in the achievement of cardiac and vascular devices, mammary implants, eye lenses, surgical threads, nervous conduits, adhesives, blood substitutes, etc. Our study was axed on the development of cytotoxicity tests for 3 synthetic polymers, namely polyvinyl alcohol, polyethylene glycol and polyvinyl chloride. These tests targeted to determi...

  20. Fontan Operation: Modification of the Valve Position in Conduit with Brief Review of the Literature

    OpenAIRE

    Sabbagh, Adib H.; Riveros, Macario; Fritz, James M.; Fernandez, Jose

    1983-01-01

    A Fontan operation was performed on a 10-year-old child for correction of tricuspid atresia. A xenograft, valved conduit was used to establish continuity between the right atrium and the small right ventricle. Atrial and ventricular septal defects were repaired with Dacron patches. Two hours postoperatively, the patient suffered a cardiac arrest secondary to hypoxia and was successfully resuscitated. Partial recurrence of a right-to-left shunt at the atrial level necessitated the patient's re...

  1. Reconstruction of upper-extremity peripheral-nerve injuries with ePTFE conduits.

    Science.gov (United States)

    Stanec, S; Stanec, Z

    1998-05-01

    This reported investigation was designed to determine the role of a new synthetic conduit-expanded polytetrafluoroethylene (ePTFE) tube--in clinical repair of median and ulnar nerves in the upper extremities. The main goals of this study were: to determine the effectiveness of the ePTFE conduit in clinical nerve reconstruction; to evaluate the potential of this technique in reconstruction of various nerve gaps (1.5 to 6 cm); and to analyze the results of repair with the ePTFE tube regarding different mechanisms of injury. Forty-three patients were evaluated. They had upper-extremity peripheral-nerve injuries (21 injuries to the median nerve, and 22 ulnar nerve injuries) located at the various levels of the upper extremities. All surgical procedures described in the study were secondary reconstructions, and the average delay from injury to repair was 4.2 months. With regard to the nerve-gap lengths, patients were categorized in two groups. Group 1 (gaps from 1.5 to 4 cm) included 28 patients (17 median nerve injuries and 11 ulnar nerve injuries), and Group 2 (gaps from 4.1 to 6 cm) comprised 15 patients (4 median nerve injuries and 11 ulnar nerve injuries). Results showed that 78.6 percent of patients from Group 1 demonstrated functional motor and sensory recovery, while reconstruction of only 13.3 percent of peripheral nerves from Group 2 resulted in useful reinnervation. According to published results, ePTFE conduit is a reliable and successful surgical procedure for nerve repair in reconstruction of nerve gaps up to 4 cm between the ends of median and ulnar nerves in various levels of the upper extremity. Because of its properties, ePTFE conduit has the advantages of promoting better nerve regeneration, compared to other synthetic tubes, especially in reconstruction of proximal nerve injuries, larger nerve gaps, and in cases with unfavorable mechanisms of nerve injury. PMID:9618088

  2. A method of gastric conduit elevation via the posterior mediastinal pathway in thoracoscopic subtotal esophagectomy

    OpenAIRE

    Hirahara Noriyuki; Yamamoto Tetsu; Tanaka Tsuneo

    2012-01-01

    Abstract Background Despite efforts to improve surgical techniques, serious complications still sometimes occur. Use of a physiological posterior mediastinal pathway has increased given advances such as automated anastomotic devices and a reduction in the incidence of anastomotic sufficiency. Until now the gastric conduit created has been protected by an echo probe cover and, sown to the ventral side of polyester tape placed through the abdomen to the neck, and then blindly elevated to the ne...

  3. The quench experiment on long length cable-in-conduit conductor (QUELL) in SULTAN

    International Nuclear Information System (INIS)

    A description of the QUELL experiment at the SULTAN facility, its objectives and plan is given. After reviewing the quench properties of the Cable in Conduit Conductors and a short review of the theoretical background foreseen for the interpretation of the experimental results, information are given concerning the QUELL sample layout, quench sensors, cryogenic system, power supplies, current bus, current leads and data acquisition system. A detailed test plan and information on the experiment time schedule are also presented

  4. 3D multi-channel bi-functionalized silk electrospun conduits for peripheral nerve regeneration.

    Science.gov (United States)

    Dinis, T M; Elia, R; Vidal, G; Dermigny, Q; Denoeud, C; Kaplan, D L; Egles, C; Marin, F

    2015-01-01

    Despite technological advances over the past 25 years, a complete recovery from peripheral nerve injuries remains unsatisfactory today. The autograft is still considered the "gold standard" in clinical practice; however, postoperative complications and limited availability of nerve tissue have motivated the development of alternative approaches. Among them, the development of biomimetic nerve graft substitutes is one of the most promising strategies. In this study, multichanneled silk electrospun conduits bi-functionalized with Nerve Growth Factor (NGF) and Ciliary Neurotropic Factor (CNTF) were fabricated to enhance peripheral nerve regeneration. These bioactive guides consisting of longitudinally oriented channels and aligned nanofibers were designed in order to mimic the fascicular architecture and fibrous extracellular matrix found in native nerve. The simple use of the electrospinning technique followed by a manual manipulation to manufacture these conduits provides tailoring of channel number and diameter size to create perineurium-like structures. Functionalization of the silk fibroin nanofiber did not affect its secondary structure and chemical property. ELISA assays showed the absence of growth factors passive release from the functionalized fibers avoiding the topical accumulation of proteins. In addition, our biomimetic multichanneled functionalized nerve guides displayed a mechanical behavior comparable to that of rat sciatic nerve with an ultimate peak stress of 4.0 ± 0.6 MPa and a corresponding elongation at failure of 156.8 ± 46.7%. Taken together, our results demonstrate for the first time our ability to design and characterize a bi-functionalized nerve conduit consisting of electrospun nanofibers with multichannel oriented and nanofibers aligned for peripheral regeneration. Our bioactive silk tubes thus represent a new and promising technique towards the creation of a biocompatible nerve guidance conduit. PMID:25460402

  5. Disintegration and Devolatilisation of Sandstone Xenolith in Magmatic Conduits: an Experimental Approach

    OpenAIRE

    Berg, Sylvia

    2010-01-01

    Xenoliths preserve evidence of magma-crust interactions in magmatic reservoirs and conduits. They reveal processes of partial melting of country rock, and disintegration into magma. Widespread evidence for frothy xenoliths in volcanic deposits exists, and these evidently indicate processes of gas liberation, bubble nucleation and bubble growth. This report focuses on textural analysis of frothy sandstone xenoliths from Krakatau in Indonesia, Cerro Negro in Nicaragua, Cerro Quemado in El Salva...

  6. Robotic Intracorporeal Ileal Conduit Formation: Initial Experience from a Single UK Centre

    OpenAIRE

    Bishop, Conrad V.; Nikhil Vasdev; Gregory Boustead; Adshead, James M.

    2013-01-01

    Objectives. To describe our technique of robotic intracorporeal ileal conduit formation (RICIC) during robotic-assisted radical cystectomy (RARC). To report our initial results of this new procedure. Patients and Methods. Seven male and one female patients underwent RARC with RICIC over a six-month period. Demographic, operative, and outcome data was collected prospectively. Median patient age was 75 years (range 62–78 years). Median followup was 9 months (range 7–14 months). Results. RAR...

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Cardiovascular effects of right ventricle-pulmonary artery valved conduit implantation in experimental pulmonic stenosis

    International Nuclear Information System (INIS)

    Right ventricle (RV)-pulmonary artery (PA) valved conduit (RPVC) implantation decreases RV systolic pressure in pulmonic stenosis (PS) by forming a bypass route between the RV and the PA. The present study evaluates valved conduits derived from canine aortae in a canine model of PS produced by pulmonary artery banding (PAB). Pulmonary stenosis was elicited using PAB in 10 conditioned beagles aged 8 months. Twelve weeks after PAB, the dogs were assigned to one group that did not undergo surgical intervention and another that underwent RPVC using denacol-treated canine aortic valved grafts (PAB+RPVC). Twelve weeks later, the rate of change in the RV-PA systolic pressure gradient was significantly decreased in the PAB+RPVC, compared with the PAB group (60.5+-16.7% vs. 108.9+-22.9%; p0.01). In addition, the end-diastolic RV free wall thickness (RVFWd) was significantly reduced in the PAB+RPVC, compared with the PAB group (8.2+-0.2 vs. 9.4+-0.7 mm; p0.05). Thereafter, regurgitation was not evident beyond the conduit valve and the decrease in RV pressure overload induced by RPVC was confirmed. The present results indicate that RPVC can be performed under a beating heart without cardiopulmonary bypass and adapted to dogs with various types of PS, including 'supra valvular' PS or PS accompanied by dysplasia of the pulmonary valve. Therefore, we consider that this method is useful for treating PS in small animals

  9. The drag coefficient for particles in aerosols flowing through a horizontal conduit

    Directory of Open Access Journals (Sweden)

    L. PEREIRA

    1999-12-01

    Full Text Available The drag coefficient, CD, was experimentally determined during sedimentation of aerosol particles in air flowing horizontally in a conduit of rectangular cross section, and its relation to the Reynolds numbers for the particle, Rep, and the conduit, Rec, was found. The method used to obtain the frictional force on the particles is based on observation of the trajectories of the particles being deposited on the bottom wall of the conduit. The diameter (dp and point of deposition of the particles were determined by examining small glass slides distributed along the floor of the apparatus at given positions. The diameter of particles adhering to these laminae can be observed by microscope, but a factor must then be applied to convert these values to the diameters in suspension (dp, since the particles are liquid and undergo flattening as they collect on the glass. Results were compared with the aerodynamic diameter of the particle, obtained independently, and the discrepancies that appeared will need to be investigated further. The velocity profiles of the air inside the apparatus were also recorded. A correlation of the form CD = f(Rep, Rec is proposed.

  10. PRGD/PDLLA conduit potentiates rat sciatic nerve regeneration and the underlying molecular mechanism.

    Science.gov (United States)

    Li, Binbin; Qiu, Tong; Iyer, K Swaminathan; Yan, Qiongjiao; Yin, Yixia; Xie, Lijuan; Wang, Xinyu; Li, Shipu

    2015-07-01

    Peripheral nerve injury requires optimal conditions in both macro-environment and micro-environment for reestablishment. Though various strategies have been carried out to improve the macro-environment, the underlying molecular mechanism of axon regeneration in the micro-environment provided by nerve conduit remains unclear. In this study, the rat sciatic nerve of 10 mm defect was made and bridged by PRGD/PDLLA nerve conduit. We investigated the process of nerve regeneration using histological, functional and real time PCR analyses after implantation from 7 to 35 days. Our data demonstrated that the ciliary neurotrophic factor highly expressed and up-regulated the downstream signaling pathways, in the case of activated signals, the expressions of axon sprout relative proteins, such as tubulin and growth-associated protein-43, were strongly augmented. Taken together, these data suggest a possible mechanism of axon regeneration promoted by PRGD/PDLLA conduit, which created a micro-environment for enhancement of diffusion of neurotrophic factors secreted by the injured nerve stumps, and activation of molecular signal transduction involved in growth cone, to potentiate the nerve recovery. PMID:25934451

  11. [Urinary diversion in patients treated with pelvic irradiation: transverse colon conduit revisited].

    Science.gov (United States)

    Matsui, Yoshiyuki; Kanematsu, Akihiro; Negoro, Hiromitsu; Kobayashi, Takashi; Terada, Naoki; Sugino, Yoshio; Yamasaki, Toshinari; Inoue, Takahiro; Kamba, Tomomi; Yoshimura, Koji; Ogawa, Osamu

    2014-08-01

    In patients receiving pelvic irradiation for gynecological or genitourinary malignancies, urinary diversion is sometimes required for complete resection of malignancies or treatment of urological complications by irradiation. We report our attempts to promote healing and prevent complications by urinary diversion using a transverse colon conduit in cases in which urinary reconstruction was performed with irradiated lower abdominal organs such as small intestine or distal ureters. Between 2008 and 2012, 9 patients with pelvic irradiation received transverse colon conduit urinary diversion. Six patients received diversion for genitourinary complications, while 3 patients received complete resection of pelvic malignancies. Colostomy formation and lithotripsy of vesical stones were simultaneously performed in 4 cases. Wallace method was adopted for ureterointestinal anastomosis. There was no operative mortality. Although acute pyelonephritis, ileus, wound dehiscence and pelvic abscess formation were seen as postoperative complications, all but two improved without any additional procedure. Cases of pelvic abscess or wound dehiscence were treated by abscess drainage. In observation periods, no patients required urinary stent placement and none suffered from defecation problems. We think that transverse colon conduit can be a viable option for patients with pelvic irradiation history, affording them reasonable quality of life postoperatively. PMID:25179985

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

    Directory of Open Access Journals (Sweden)

    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(?-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 is believed that this electrospun nerve conduit could find more application in cell therapy for nerve regeneration in future, to further improve functional regeneration outcome especially for longer nerve defect restoration.

  13. Delayed cervical esophagogastrostomy: a surgical alternative for patients with ischemia of the gastric conduit at time of esophagectomy.

    Science.gov (United States)

    Lanzarini, Enrique; Ramón, José M; Grande, Luis; Pera, Manuel

    2014-01-01

    Ischemia of the gastric conduit after esophagectomy represents a setback that increases the risk of anastomotic leak. In order to prevent this severe complication, a surgical alternative has been proposed which consists in delaying the reconstruction until gastric perfusion improves. By adopting this strategy we can avoid two other surgical options that may significantly increase the risk of complications: 1) performing an esophagogastrostomy with a poorly perfused gastric tube and 2) resecting the gastric conduit followed by a complex reconstruction. PMID:24631236

  14. Linking conduit and surface activity at Arenal volcano using broadband seismometers and Doppler radar: do we need a new conduit model?

    Science.gov (United States)

    Valade, S.; Donnadieu, F. R.; Lesage, P.; Mora Fernandez, M.; Harris, A. J.; Alvarado, G. E.

    2010-12-01

    We carried out a cross-correlation of broadband seismic data and ground-based Doppler radar data obtained at Arenal (Costa Rica) in February 2005. Our aim was to gain insight into the subsurface source processes (i.e., fragmentation mechanisms operating in the shallow conduit system) and the subsequent pyroclastic emissions (i.e., plume mass loading and ascent dynamics) that characterize the transitory, mildly explosive activity at Arenal. Study of the radar and seismic waveforms revealed a non-systematic relationship between them, both exhibiting a large variety of behaviors and features, but no clear patterns could be distinguished. Pyroclastic emissions recorded by the radar also did not have a unique seismic signature: 44% of radar signals were found in association with explosion-type seismic events, 43% during episodes of tremor, and 13% during aseismic intervals. Over longer time-scales, radar event amplitudes showed no correlation with the seismic energy release rate (RSEM), nor with RSAM, nor with repose time intervals. Energy proxies obtained from coeval radar (plume energy) and seismic (explosion energy) data show significant scattering, indicating that the ratio of the seismic/radar energy was highly variable. Plume mass-loading and exit velocity thus seems only weakly correlated to the seismic energy generated by the explosion, suggesting that the seismic energy might not be a good indicator of the intensity of explosions at Arenal. The occurrence of radar echoes in different range gates indicates that several vents were active, which is consistent with the clarinet-model for tremor generation at Arenal (Lesage et al., 2006), in which fractures in the plug act as valves that control degassing, with multiple conduits explaining the occurrence of different sets of harmonic frequencies in seismic data. Fragmentation is best explained by pressure build-up below a plug obstructing the conduit. This, when a resistance threshold is overcome, fails and yields sudden decompression, allowing gas bubbles in the magma to rapidly expand and fragment the viscous host magma. Nevertheless, this model fails to explain the full spectrum of activity, recorded signals, and seismo/radar energy partitioning. Variable source depth may, though, cause variation in elastic energy radiation, and variable fragmentation mechanisms may explain varying seismic signals associated with the emissions. It is possible that non-linear, inter- and time-dependent, processes explain unstable dynamic systems such as Arenal, and are required to trigger transitions from one fragmentation mechanism to another.

  15. Thermal conductivity of mercury vapor

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, J R

    1977-01-01

    The method employing the frequency response of a thin hot wire has been used to determine the thermal conductivity of mercury vapor in a temperature range from 254/sup 0/C to 992/sup 0/C with an average superheat range up to 75/sup 0/C. A thin tungsten wire was surrounded by mercury vapor in a cell and heated with an alternating current. The thermal conductivity of the mercury vapor was determined relative to that of argon by comparing the frequency response of the same wire to both mercury vapor and argon. In addition, the phenomenon of mercury dimerization is discussed. Several references on the diatomic nature of mercury vapor at various operating conditions have been correlated and the effects of the disassociation of mercury vapor on its thermal conductivity estimated. An empirical correlation for percent dimer as a function of temperature and pressure is presented.

  16. Water vapor retrieval from OMI visible spectra

    Directory of Open Access Journals (Sweden)

    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. Water Vapor Circulation on Earth

    Science.gov (United States)

    Water vapor plays an important role in the water cycle and in the distribution of heat around the planet. By observing the movement of water vapor, scientists can study global wind patterns and the development of cyclonic storms. This simulation from the National Center for Atmospheric Research shows the circulation of water vapor around the Earth over the course of a year. The segment is four minutes fifty-two seconds in length. Quicktime is required to view the clip.

  18. Hydrazine-Vapor Samplers

    Science.gov (United States)

    Young, Rebecca; Mcbrearty, Charles; Curran, Dan; Leavitt, Nilgun

    1994-01-01

    Active sampling unit capable of detecting hydrazine and monomethyl hydrazine vapors at levels as low as 10 ppb in air developed. Includes detachable badge holder and pump which draws air through badge holder at selectable rate of 1 or 2 L/min. Coated strip in each badge designed to align with air passage in badge holder. Two types of badge holders constructed: one has open-face design for general monitoring of air in open spaces, while other has closed-face design with viewing window and intended for sampling through small openings to detect leaks.

  19. Numerical analysis of hydraulic characteristics of fracture intersected with karst conduit based on navier-stokes equation

    Science.gov (United States)

    Tao, X.; Zhao, J.; Zhao, Z.; Li, Y.; Qiu, L.

    2013-12-01

    The flow in karstic geometry is an important problem in groundwater researches and engineering applications. However, the mechanism controlling the flow status in these areas is still not clear. In this study, we investigated the hydraulic characteristics with numerical models considering a single fracture intersected with a karst conduit. The numerical model used here is a FVM model based on Navier-Stokes equation which was successfully verified with the test result taken from literature. Five factors and four levels were considered in this study, including the length of the karst conduit, aperture of the fracture, diameter of the conduit, hydraulic condition and the cross angle and sixteen cases were designed according to orthogonal design. A non-dimensional number ? (the ratio of the fracture aperture to diameter of the conduit) was defined in analysis of the combined effect of the two factors on flow characters. The most important impacting factors and the stability levels were obtained in order to improve the accuracy of the results in numerical simulations. A mathematical model was built for the relationship between discharge of the conduit and the impacting factors with consideration of the combined effects based on dimension analysis and changeable structure genetic algorithm. The converting permeability coefficient was estimated in order to solve the stream wise head loss considering the combined effects of the flow in karst conduit and fractures with Darcy's law. The results show that the most important impacting factor for flux might be the fracture aperture or the diameter of the conduit which is determined by the non-dimensional number ?. The conduit has more influence on the whole pressure field with larger diameter and smaller length. The head loss has a non-linear relationship with the velocity because of the local head loss near the karst conduit. Thus, the local cubic's law is no longer applicable to characterize the flow in the fracture near the conduit. In this situation, the flow can be simulated by the general Darcy's law form with the converting permeability coefficient.

  20. Shock Wave Formation in the Collapse of a Vapor Nanobubble

    Science.gov (United States)

    Magaletti, F.; Marino, L.; Casciola, C. M.

    2015-02-01

    In this Letter, the dynamics of a collapsing vapor bubble is addressed by means of a diffuse-interface formulation. The model cleanly captures, through a unified approach, all the critical features of the process, such as phase change, transition to supercritical conditions, thermal conduction, compressibility effects, and shock wave formation and propagation. Rather unexpectedly for pure vapor bubbles, the numerical experiments show that the process consists in the oscillation of the bubble associated with the emission of shock waves in the liquid, and with the periodic disappearance and reappearance of the liquid-vapor interface due to transition to super- or subcritical conditions. The results identify the mechanism of shock wave formation as strongly related to the transition of the vapor to the supercritical state, with a progressive steepening of a focused compression wave evolving into a shock which is eventually reflected as an outward propagating wave in the liquid.

  1. Sample Means

    Science.gov (United States)

    Lacey, Michelle

    This site, presented by the Department of Statistics at Yale University, gives an explanation of, a definition for and an example of sample means. Topics include mean, variance, distribution, and the central limit theorem. Overall, this is a great resource for any mathematics classroom studying statistics.

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

    LENUS (Irish Health Repository)

    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.

  3. Laboratory analog and numerical study of groundwater flow and solute transport in a karst aquifer with conduit and matrix domains.

    Science.gov (United States)

    Faulkner, Jonathan; Hu, Bill X; Kish, Stephen; Hua, Fei

    2009-11-01

    New mathematical and laboratory methods have been developed for simulating groundwater flow and solute transport in karst aquifers having conduits imbedded in a porous medium, such as limestone. The Stokes equations are used to model the flow in the conduits and the Darcy equation is used for the flow in the matrix. The Beavers-Joseph interface boundary conditions are adopted to describe the flow exchange at the interface boundary between the two domains. A laboratory analog is used to simulate the conduit and matrix domains of a karst aquifer. The conduit domain is located at the bottom of the transparent plexiglas laboratory analog and glass beads occupy the remaining space to represent the matrix domain. Water flows into and out of the two domains separately and each has its own supply and outflow reservoirs. Water and solute are exchanged through an interface between the two domains. Pressure transducers located within the matrix and conduit domains of the analog provide data that is processed and stored in digital format. Dye tracing experiments are recorded using time-lapse imaging. The data and images produced are analyzed by a spatial analysis program. The experiments provide not only hydraulic head distribution but also capture solute front images and mass exchange measurements between the conduit and matrix domains. In the experiment, we measure and record pressures, and quantify flow rates and solute transport. The results present a plausible argument that laboratory analogs can characterize groundwater water flow, solute transport, and mass exchange between the conduit and matrix domains in a karst aquifer. The analog validates the predictions of a numerical model and demonstrates the need of laboratory analogs to provide verification of proposed theories and the calibration of mathematical models. PMID:19767123

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Optimization of JK2LB chemical composition for ITER Central Solenoid conduit material

    Science.gov (United States)

    Hamada, Kazuya; Nakajima, Hideo; Kawano, Katsumi; Takano, Katsutoshi; Tsutsumi, Fumiaki; Okuno, Kiyoshi; Suzuki, Tomio; Fujitsuna, Nobuyuki

    2007-03-01

    The Japan Atomic Energy Agency (JAEA) has developed a cryogenic structural steel to be used in large superconducting magnets for a fusion machine, and the results of this development will be utilized in the International Thermonuclear Experimental Reactor (ITER). Low carbon and low boron JK2 (JK2LB), which has high strength and fracture toughness at 4 K and thermal contraction from room temperature to 4 K which is lower than that of conventional 316LN steel has been developed as the conduit material for the ITER Central Solenoid (CS) conductor. In order to achieve the ITER requirements (0.2% yield strength ? 1000 MPa, fracture toughness KIC (J) ? 130 MPa ?{m}) for CS conduit material, chemical components such as carbon, nitrogen and boron, were optimized. In addition, since the CS is to undergo 6 × 10 4 load cycles during its lifetime with a maximum principal stress of 490 MPa, fatigue crack growth assessment of the CS conduit was performed. As the result, JK2LB containing nitrogen of 0.2%, boron 15-40 ppm, and low carbon was found to achieve the strength and fracture toughness requirements. For the welding of JK2LB, a filler wire of JK2LB with a low nitrogen content of 0.13% was developed and fracture toughness of more than 130 MPa ?{m} was confirmed in the weld metal. Measured fatigue crack growth rates of the base and weld metal at 4 K are low enough to achieve the required CS coil operation cycle lifetime.

  6. Orientated Guidance of Peripheral Nerve Regeneration Using Conduits with a Microtube Array Sheet (MTAS).

    Science.gov (United States)

    Wang, Yueming; Wang, Wenjin; Wo, Yan; Gui, Ting; Zhu, Hao; Mo, Xiumei; Chen, Chien-Chung; Li, Qingfeng; Ding, Wenlong

    2015-04-29

    Material surface topography has been shown to affect the biological behavior of cells in vitro; however, the in vivo effect on peripheral nerve regeneration has not been explored. Here, we studied the potential of a microtube array sheet (MTAS) with a unique longitudinal surface topography to promote peripheral nerve regeneration efficiency, both in vivo and in vitro. Schwann cells, spinal cord motor neurons, and dorsal root ganglion neurons were seeded on the MTAS to study the effect of the construct on the biological properties and behaviors of neural cells. The MTAS guided the oriented migration of Schwann cells without affecting other critical biological properties, such as proliferation and neurotrophin expression. In addition, the MTAS guided the directed extension of neurites from both types of neurons. Next, we tested the capability of the MTAS to facilitate peripheral nerve regeneration by bridging a 10 mm sciatic nerve defect in rats with a nerve conduit equipped with an MTAS lining. The MTAS significantly promoted peripheral nerve regeneration, as suggested by the greater fiber caliber in the midconduit and the greater abundance of fibers in nerve segment distal to the conduit. Moreover, scanning electron microscopy (SEM) analysis suggested the orientated guidance of nerve regeneration by the MTAS, as indicated by the smaller eccentricity of the nerve fibers and the concordant arrangement of the collagen fiber in both the fibers and the matrix in the MTAS group. Our results collectively suggest that the conduits with the MTAS developed in this study have significant potential for facilitating peripheral nerve regeneration by modifying critical biological behaviors and guiding orientated nerve growth. PMID:25853547

  7. Vapor-droplet flow equations

    International Nuclear Information System (INIS)

    General features of a vapor-droplet flow are discussed and the equations expressing the conservation of mass, momentum, and energy for the vapor, liquid, and mixture using the control volume approach are derived. The phenomenological laws describing the exchange of mass, momentum, and energy between phases are also reviewed. The results have application to development of water-dominated geothermal resources

  8. Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    Science.gov (United States)

    Moore, Karen A.; Zatorski, Raymond A.

    2005-07-12

    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.

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

    Science.gov (United States)

    Moore, Karen A. (Idaho Falls, ID); Zatorski, Raymond A. (East Hampton, CT)

    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. Vapor pressure measured with inflatable plastic bag

    Science.gov (United States)

    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.

  11. Use of a newly developed artificial nerve conduit to assist peripheral nerve regeneration across a long gap in dogs.

    Science.gov (United States)

    Matsumoto, K; Ohnishi, K; Sekine, T; Ueda, H; Yamamoto, Y; Kiyotani, T; Nakamura, T; Endo, K; Shimizu, Y

    2000-01-01

    There is now considerable evidence that peripheral nerves have the potential to regenerate if an appropriate microenvironment is provided. However, there are only a few reports of the successful use of artificial nerve conduits to repair major nerve defects more than 30 mm in length. In this study, we examined nerve regeneration across a long gap in the dog peroneal nerve using a novel artificial nerve conduit developed by our group. The conduit consists of a polyglycolic acid (PGA) collagen tube filled with laminin coated collagen fibers. In 12 dogs, the nerve conduit was implanted across an 80 mm gap in the left peroneal nerve. Three months after surgery, compound muscle action potentials (CMAPs) and somatosensory evoked potentials (SEPs) were detected. Evaluation of locomotor function revealed obvious limping for up to 3 months, but no marked difficulty in walking by 6 months. Microscopic observation of the regenerated nerve segment at 12 months showed numerous myelinated nerve fibers, which were smaller in diameter and enclosed in a thinner myelin sheath than normal axons. These results suggest that our artificial nerve conduit has potential usefulness in enhancing peripheral nerve regeneration, even across large gaps. PMID:10926137

  12. Surface reaction of titanium beryllide with water vapor

    International Nuclear Information System (INIS)

    Beryllium is one of the candidate materials for the neutron multiplier in the tritium-breeding blanket. However, there are some problems related to the application of beryllium as a neutron multiplier, which include compatibility with structural materials, tritium inventory and reaction of beryllium with water vapor and oxygen in a LOCA accident. Titanium beryllides such as Be12Ti are known to have advantages over beryllium from the perspectives of higher melting point, lower chemical reactivity and lower swelling. Thus, these materials are promising alternatives of beryllium. The authors investigate here the reaction of titanium beryllides with water vapor at high temperatures, and it is found that Be12Ti is by far more tolerant to water vapor than beryllium. To clarify the high tolerance of Be12Ti to water vapor, the surface of Be12Ti used in the experiment was investigated by means of digital microscope, SEM, XRD and electron spectroscopy for chemical analysis (ESCA). These analyses suggest that some oxidized state of beryllium was formed on the surface of Be12Ti exposed to water vapor. In particular, the results of the ESCA analysis gave some clues to understanding the higher tolerance of Be12Ti to water vapor at high temperatures

  13. 3D Printed Trileaflet Valve Conduits Using Biological Hydrogels and Human Valve Interstitial Cells

    Science.gov (United States)

    Duan, Bin; Kapetanovic, Edi; Hockaday, Laura A.; Butcher, Jonathan T.

    2014-01-01

    Tissue engineering has great potential to provide a functional de novo living valve replacement capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, 3D bioprinting enables deposition of cells and hydrogels into 3D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach is however constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not known how human valve cells respond to these printed environments. In this study, we develop 3D printable formulations of hybrid hydrogels based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and utilize them to bioprint heart valve conduits containing encapsulated human aortic valvular interstitial cells (HAVIC). Increasing Me-Gel concentration resulted in lower stiffness and higher viscosity, facilitated cell spreading, and better maintained HAVIC fibroblastic phenotype. Bioprinting accuracy was dependent upon the relative concentrations of Me-Gel and Me-HA, but when optimized enabled the fabrication of a trileaflet valve shape accurate to the original design. HAVIC encapsulated within bioprinted heart valves maintained high viability, and remodeled the initial matrix by depositing collagen and glyosaminoglycans. These findings represent the first rational design of bioprinted trileaflet valve hydrogels that regulate encapsulated human VIC behavior. The use of anatomically accurate living valve scaffolds through bioprinting may accelerate our understanding of physiological valve cell interactions and our progress towards de novo living valve replacements. PMID:24334142

  14. Three-dimensional printed trileaflet valve conduits using biological hydrogels and human valve interstitial cells.

    Science.gov (United States)

    Duan, B; Kapetanovic, E; Hockaday, L A; Butcher, J T

    2014-05-01

    Tissue engineering has great potential to provide a functional de novo living valve replacement, capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, three-dimensional (3-D) bioprinting enables deposition of cells and hydrogels into 3-D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach, however, is constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not known how human valve cells respond to these printed environments. In this study, 3-D printable formulations of hybrid hydrogels are developed, based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and used to bioprint heart valve conduits containing encapsulated human aortic valvular interstitial cells (HAVIC). Increasing Me-Gel concentration resulted in lower stiffness and higher viscosity, facilitated cell spreading, and better maintained HAVIC fibroblastic phenotype. Bioprinting accuracy was dependent upon the relative concentrations of Me-Gel and Me-HA, but when optimized enabled the fabrication of a trileaflet valve shape accurate to the original design. HAVIC encapsulated within bioprinted heart valves maintained high viability, and remodeled the initial matrix by depositing collagen and glyosaminoglycans. These findings represent the first rational design of bioprinted trileaflet valve hydrogels that regulate encapsulated human VIC behavior. The use of anatomically accurate living valve scaffolds through bioprinting may accelerate understanding of physiological valve cell interactions and progress towards de novo living valve replacements. PMID:24334142

  15. Traitements de substitution et conduite automobile Opiate addiction treatment and driving

    Directory of Open Access Journals (Sweden)

    Gaulier Jean-Michel

    2009-03-01

    Full Text Available Les médicaments de substitution (méthadone et buprénorphine, à l'instar d'autres médicaments psychotropes, possèdent des propriétés pharmacologiques susceptibles de perturber l'aptitude à la conduite automobile. Sur la base des données neurocomportementales, expérimentales et épidémiologiques disponibles, le risque de survenue d'accident de la voie publique dépend du stade du traitement et d'éventuelles associations avec d'autres psychotropes. La seule étude comparative retrouvée dans la littérature semble indiquer que la buprénorphine modifierait moins l'aptitude à la conduite automobile que la méthadone. Potential impairing effects on driving can be expected with the compounds used for opiate addiction treatment (methadone and buprenorphine, owing to their pharmacological properties, as with numerous other psychoactive drugs. The review of neurobehavioural, experimental and epidemiological data shows an increased risk of crash at the beginning of the treatment and in case of drug association. The sole comparative study found in the literature showed that buprenorphine induced less psychomotor impairment than methadone.

  16. Robotic Intracorporeal Ileal Conduit Formation: Initial Experience from a Single UK Centre.

    Science.gov (United States)

    Bishop, Conrad V; Vasdev, Nikhil; Boustead, Gregory; Adshead, James M

    2013-01-01

    Objectives. To describe our technique of robotic intracorporeal ileal conduit formation (RICIC) during robotic-assisted radical cystectomy (RARC). To report our initial results of this new procedure. Patients and Methods. Seven male and one female patients underwent RARC with RICIC over a six-month period. Demographic, operative, and outcome data was collected prospectively. Median patient age was 75 years (range 62-78 years). Median followup was 9 months (range 7-14 months). Results. RARC with RICIC was performed successfully in all eight patients. The median total operating time was 360 minutes (range 310-440 minutes) with a median blood loss of 225?mL (range 50-1000?mL). The median length of stay was nine days (range 6-34 days). Four patients (50%) were discharged within seven days. Four patients (50%) experienced one or more complications. This included two Clavien I complications, two Clavien II complications, and two Clavien III complications. Two patients (25%) required transfusion of two units each. To date, there have been no complications associated with the ileal conduit. Conclusion. Whilst being technically challenging, this procedure is safe, feasible, and reproducible. Patients who avoid complication show potential for rapid recovery and early discharge. PMID:24072995

  17. Exercise training improves conduit vessel function in patients with coronary artery disease.

    Science.gov (United States)

    Walsh, Jennifer H; Bilsborough, William; Maiorana, Andrew; Best, Matthew; O'Driscoll, Gerard J; Taylor, Roger R; Green, Daniel J

    2003-07-01

    It is well established that endothelial dysfunction is present in coronary artery disease (CAD), although few studies have determined the effect of training on peripheral conduit vessel function in patients with CAD. A randomized, crossover design determined the effect of 8 wk of predominantly lower limb, combined aerobic and resistance training, in 10 patients with treated CAD. Endothelium-dependent dilation of the brachial artery was determined, by using high-resolution vascular ultrasonography, from flow-mediated vasodilation (FMD) after ischemia. Endothelium-independent vasodilation was measured after administration of glyceryl trinitrate (GTN). Baseline function was compared with that of 10 control subjects. Compared with matched healthy control subjects, FMD and GTN responses were significantly impaired in the untrained CAD patients [3.0 +/- 0.8 (SE) vs. 5.8 +/- 0.8% and 14.5 +/- 1.9 vs. 20.4 +/- 1.5%, respectively; both P improved FMD in the CAD patients (from 3.0 +/- 0.8 to 5.7 +/- 1.1%; P Exercise training improves endothelium-dependent conduit vessel dilation in subjects with CAD, and the effect, evident in the brachial artery, appears to be generalized rather than limited to vessels of exercising muscle beds. These results provide evidence for the benefit of exercise training, as an adjunct to routine therapy, in patients with a history of CAD. PMID:12794092

  18. Passive vapor extraction feasibility study

    International Nuclear Information System (INIS)

    Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft3/min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft3/min air flow rates, passive vapor extraction is more cost effective below 100 ppm

  19. Nonlinear phenomena in fluids with temperature-dependent viscosity an hysteresis model for magma flow in conduits

    CERN Document Server

    Costa, A; Costa, Antonio; Macedonio, Giovanni

    2002-01-01

    Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. As a consequence, this system may show an hysteresis effect, and the transition between the two branches can occur quickly when certain critical points are reached. In this paper we describe a model to study the relation between the pressure at the inlet and the volumetric magma flow rate in a conduit. We apply this model to explain an hysteric jump observed during the dome growth at Soufri\\`ere Hills volcano (Montserrat), and described by Melnik and Sparks [1999] using a different model.

  20. 33 CFR 154.808 - Vapor control system, general.

    Science.gov (United States)

    2010-07-01

    ...part must provide a remote indicator on the facility where the...provided to eliminate any liquid condensate from the vapor...A means to indicate the level of liquid in the device; (2) A high liquid level sensor that activates...

  1. Upscaling Pumice-Sized Bubble Networks to the Volcanic Conduit Scale: Implications for Magma Permeabilities and Volatile Degassing Rates

    Science.gov (United States)

    Davis, M. A.; Walsh, S. D.; Anderson, K. J.; Saar, M. O.

    2006-12-01

    Magmatic volatile gases can be a significant contributor to pressure build-up within a volcano conduit prior to or during an eruption, potentially influencing eruption styles (effusive versus explosive). However, if bubbles connect to form a "bubble network" at the scale of the conduit, it may be possible for these volatiles to degas to the country rock, releasing gas pressure. Yet, it is not possible to directly measure such bubble networks, their permeabilities, and related volatile degassing rates before or during an eruption. Therefore, these conduit parameters typically have to be inferred from eruption products, such as pumices, at much smaller scales. However, it is well known that permeability, the critical parameter in this study, is often scale-dependent [Sánchez-Vila et al., J. Hydrol., 1996]. As a result, this study focuses on techniques to upscale pumice- sized bubble networks (revealed by x-ray tomography images) to the conduit scale for later permeability determinations employing Lattice-Boltzmann gas flow simulations. In these pumice clasts, spatial relationships of bubbles (orientation, connectivity, tortuosity of bubble networks) can have a substantial effect on measured and calculated permeabilities. We show how so-called spatial correlation functions may be used in conjunction with percolation theory to determine a bubble network's permeability at the appropriate conduit scale. Such permeabilities may then be combined with estimates of pressure gradients to calculate likely volatile degassing rates through the large-scale numerical bubble network. This approach may also be employed to determine permeabilities of fracture networks within fragmenting conduit magmas, which have similar scale dependence.

  2. Transplantation of Autologous Minced Bladder Mucosa for a One-Step Reconstruction of a Tissue Engineered Bladder Conduit

    OpenAIRE

    Magdalena Fossum; Agneta Nordenskjöld; Johan Lundberg; Clara Ibel Chamorro; Gisela Reinfeldt Engberg

    2013-01-01

    Surgical intervention is sometimes needed to create a conduit from the abdominal wall to the bladder for self-catheterization. We developed a method for tissue engineering a conduit for bladder emptying without in vitro cell culturing as a one-step procedure. In a porcine animal model bladder, wall tissue was excised and the mucosa was minced to small particles. The particles were attached to a tube in a 1?:?3 expansion rate with fibrin glue and transplanted back by attaching the tube to ...

  3. Measurements of stability margins and current distribution in large-scale Nb3Sn cable-in-conduit conductors

    International Nuclear Information System (INIS)

    The main goal of the ITER Conductor Testing Program is to validate the design and the fabrication process of the CICC (Cable-In-Conduit Conductor) and its joints, in full-size samples. For testing large-scale cable-in-conduit conductors, several practical experimental techniques have been developed to specifically address the issues of conductor stability. The following described techniques enable experimentalists to quantify the effects and thus provide useful tools to improve the conductor performance in magnet applications. In this paper, the authors, present two experimental techniques: (a) stability margin calibration and (b) current distribution. Both are much needed in the laboratory for testing the conductor stability

  4. Understanding Latent Heat of Vaporization.

    Science.gov (United States)

    Linz, Ed

    1995-01-01

    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  5. Portable vapor diffusion coefficient meter

    Science.gov (United States)

    Ho, Clifford K. (Albuquerque, NM)

    2007-06-12

    An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

  6. Análise do tratamento cirúrgico da raiz da aorta com o tubo valvulado e com a preservação da valva aórtica / Analysis of aortic root surgery with composite mechanical aortic valve conduit and valve-sparing reconstruction

    Scientific Electronic Library Online (English)

    Ricardo Ribeiro, Dias; Omar Asdrubal Vilca, Mejia; Alfredo Inácio, Fiorelli; Pablo Maria Alberto, Pomerantzeff; Altamiro Ribeiro, Dias; Charles, Mady; Noedir Antonio Groppo, Stolf.

    2010-12-01

    Full Text Available OBJETIVO: Análise comparativa dos resultados imediatos e tardios da reconstrução da raiz da aorta com o tubo valvulado e com a preservação da valva aórtica. MÉTODOS: No período de novembro de 2002 a setembro de 2009, 164 pacientes com idade média de 54 ± 15 anos, sendo 115 do sexo masculino, foram s [...] ubmetidos ao tratamento cirúrgico da raiz da aorta. Foram 125 tubos valvulados e 39 reconstruções da raiz da aorta com preservação da valva aórtica. Dezesseis por cento dos pacientes eram portadores de síndrome de Marfan e 4,3% apresentavam valva aórtica bivalvulada. Cento e quarenta e quatro (88%) pacientes foram acompanhados durante tempo médio de seguimento de 41,1 ± 20,8 meses. RESULTADOS: A mortalidade hospitalar total foi de 4,9%; sendo 5,6% nas operações com tubo valvulado e 2,6% nas preservações da valva aórtica (P Abstract in english OBJECTIVE: Comparative analysis of early and late results of aortic root reconstruction with aortic valve sparing operations and the composite mechanical valve conduit replacement. METHODS: From November 2002 to September 2009, 164 consecutive patients with mean age 54 ± 15 years, 115 male, underwen [...] t the aortic root reconstruction (125 mechanical valve conduit replacements and 39 valve sparing operations). Sixteen percent of patients had Marfan syndrome and 4.3% had bicuspid aortic valve. One hundred and forty-four patients (88%) were followed for a mean period of 41.1 ± 20.8 months. RESULTS: The hospital mortality was 4.9%, 5.6% in operations with valved conduits and 2.6% in the valve sparing procedures (P

  7. Stable isotopic composition of water vapor in the tropics

    Science.gov (United States)

    Lawrence, James Robert; Gedzelman, Stanley David; Dexheimer, Darielle; Cho, Hye-Khung; Carrie, Gordon D.; Gasparini, Robert; Anderson, Casey R.; Bowman, Kenneth P.; Biggerstaff, Mike I.

    2004-03-01

    Water vapor samples collected during tropical field experiments at Puerto Escondido, Mexico, near Kwajalein (KWAJEX), and near Key West, Florida (CAMEX 4), were analyzed for their stable isotope contents, 1H218O:1H216O and 2H1H16O:1H216O. Highest ?18O values approached isotopic equilibrium with seawater during quiescent weather or in regions of isolated or disorganized convection. Lowest ?18O values occurred in or downwind from regions of organized mesoscale weather disturbances and ranged as low as 15‰ below isotopic equilibrium with seawater. The mean ?18O value of vapor over the sea surface therefore decreases as storm activity and organization increases.

  8. A Review of Vapor Intrusion Models

    OpenAIRE

    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...

  9. controlled water vapor conditions

    Directory of Open Access Journals (Sweden)

    M.A. V\\u00E1squez-A.

    2007-01-01

    Full Text Available Se presenta un estudio de la evoluci´on de las caracter´?sticas de los espectros de FTIR y la respuesta de fotoluminiscencia (PL en pel´?culas de silicio poroso (PSL oxidadas qu´?micamente y envejecidas en condiciones controladas. Las PSL se obtuvieron por el m´etodo electroqu´?mico para obtener buena uniformidad en grandes ´areas. Las mediciones de FTIR en las PSL reci´en preparadas manifiestan bandas de siliciohidrogeno asociadas con la terminaci´on en hidrogeno de superficie de silicio poroso justo despu´es del proceso de porificaci´on. Al oxidar las pel´?culas, los distintos modos de vibraci´on se modifican. Esos modos de vibraci´on se relacionan con los defectos en el oxido de silicio que recubre la superficie del silicio poroso. Los espectros de PL en muestras reci´en preparadas presentan un m´aximo en »700 nm. El espectro de PL en las PSL oxidadas qu´?micamente y luego envejecidas, en condici´on de vapor de agua saturado, se modifica fuertemente con respecto a las muestras reci´en obtenidas. Estas variaciones est´an asociadas con los cambios en la estructura de las PSL inducidos por los procesos de oxidaci´on. Los datos de FTIR y el comportamiento de la se?nal de PL nos permiten relacionar estas se?nales con los efectos de cuantizaci´on por peque?nas dimensiones e indicar que las transiciones a altas energ´?as las produce alg´un centro de defecto en la pel´?cula de ´oxido de silicio que se forma en su superficie. Las caracter´?sticas de las PSL reportadas en este trabajo son perfectamente reproducibles en las condiciones que se utilizaron para prepararlas; por ello, las pel´?culas pueden usarse en distintas aplicaciones.

  10. Villarrica volcano (Chile): characteristics of the volcanic tremor and forecasting of small explosions by means of a material failure method

    Science.gov (United States)

    Ortiz, R.; Moreno, H.; García, A.; Fuentealba, G.; Astiz, M.; Peña, P.; Sánchez, N.; Tárraga, M.

    2003-11-01

    Villarrica volcano (Chile, 39.42°S, 71.93°W) is one of the most active volcanoes in the Andes. It shows persistent strombolian activity in a small lava lake situated at the bottom of the summit crater. From September to December 2000, the volcano exhibited anomalous behaviour: after a regional tectonic seismic event on 22 September, the eruption of a small volume of lava apparently plugged the conduit. This situation then lasted for ten days. On 5 and 8 October, a series of explosions reopened the system. This eruption behaviour has allowed us to study the evolution of the characteristic tremor in the open and closed states of the conduit: a shift in the peak frequency from 1 Hz (open) to 2 Hz (closed). The explosions related to the opening of the conduit were forecasted by means of a material failure method.

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

    Science.gov (United States)

    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 to flow conditions and observed regimes. The experiments showed a progressive increase of the average vesicularity of the liquid column with increasing gas flux, but also the onset of pressure and void fraction fluctuations whose amplitude and frequency increases with increasing gas fluxes. In all the experiments, bubble rise generated liquid circulation cells and mixing at the column scale. Gradual variations of flow properties marked the onset of bubbly to intermittent to annular flow regimes. Strong differences in the relative importance of shearing and turbulent effects in the glucose syrup and water experiments generated significant variations in the flow dynamics affecting bubble coalescence and breakup, vesicularity and bubble size. This indicates that the stability and characteristics of the two-phase flow regimes are strongly affected by variations of the liquid viscosity. Finally, acoustic signals were generated at higher gas fluxes in the glucose syrup experiments by bursts of large bubbles at the liquid surface indicating significant overpressure buildup.

  12. SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN

    International Nuclear Information System (INIS)

    Eruptive conduit geometry has direct relation to number of waste packages that would be damaged if a new volcano were to form at the proposed Yucca Mountain radioactive waste repository, and therefore is a key factor in predicting the consequences of such an eruption. Current risk calculations treat conduits as having circular plan view and range from a few meters to 150 m diameter at repository depths (?300 m). We present new observations of shallow basaltic plumbing at analog sites aimed at testing these parameter values. East Grants Ridge. NM, is a remnant of a ?2.6 Ma alkali basaltic volcano with a chain of 2-3 vents that fed ?10-km long lava flows. The south side of the ridge exposes a plug of vertically jointed, dense basalt that intruded rhyolitic tuffs. The plug is exposed vertically for ?125 m, including 40 m beneath the paleosurface, and has a relatively constant width of ?135 m with no indication of downward narrowing. The size of the plug in the third dimension is not well known but could extend laterally up to ?1.5 km beneath the chain of vents. Paiute Ridge, NV, is an 8.6 Ma alkali basalt intrusion into Paleozoic carbonate and shale and Miocene silicic tuffs and includes extrusive equivalents. Dikes, small sills and lopoliths, scoria, and flows are exposed in a 2 km-wide graben. Depth of intrusion has been estimated at 100-250 m beneath the paleosurface. Dikes range from 3-20 m in width and produced limited contact vitrophyre in the host tuff. At least one sub-volcanic neck is preserved. The top of the plug is ?27 m lower than the base of related basalt flows 1 km distant. This neck is irregularly shaped by intersection of feeder dikes and has a sheath of mixed basaltic magma and host tuff (with both breccia and fluidal textures). The basalt interior of the plug is ?100 m x 70 m in map view but inclusion of the mixed zone increases this to ?220 m x 110 m. Basalt Ridge, NV, contains two remnants (9.1 Ma; 8.8 Ma) of basalt dikes, vent, spatter, scoria, and flow facies, with exposures to ?270 m beneath the paleosurface. Basalt Ridge ''East'' (BRE) contains breccias, agglutinates, and flows capping a linear ridge for 1,600 m; feeder dikes extend laterally beyond the eruptive products. The adjacent canyon reveals gradual decrease in feeder thickness from an 80-100 m-wide vent to a 40 m-wide zone of dikes plus host tuff (35 m beneath paleosurface), to 1-2 dikes in a 4 m-wide zone (270 m beneath paleosurface). BRE reveals no ''conduit'' extending to significant depth. Instead, multiple thin dikes rise vertically in non-welded and welded tuffs at repository depths. The above observations are roughly consistent with the range of conduit diameters currently used in consequence calculations, although they may support an extension of the size range so that some large diameters are accounted for at lower probabilities

  13. Seismological constraints on the position of the fragmentation surfaces in the volcano conduit

    Science.gov (United States)

    Zobin, Vyacheslav M.; Reyes, Gabriel A.; Guevara, Enrique; Bretón, Mauricio

    2008-11-01

    The durations of the pre-explosion low-frequency impulses of the broadband seismic records of 286 Vulcanian explosions of Volcán de Colima and 15 Vulcanian explosions of Popocatépetl volcano, México were analyzed. These pre-explosion impulses are thought to be produced during the upward movement of fragmented magma in the volcano conduit before an explosion. It is shown that three different magma fragmentation surfaces acted simultaneously during the 2004 September-November episode at Volcán de Colima associated with the andesitic block lava extrusion. The optimal apparent depth for the fragmentation surface that generated the largest (with the energy ? 10 11 J) 2004-2005 explosions at Volcán de Colima and the 1998-2000 Popocatépetl explosions is constrained by pre-explosion low-frequency impulse durations between 3 and 7 s.

  14. Pockets, conduits, channels, and plumes: links to volcanism and orogeny in the rollback dominated western Mediterranean

    Science.gov (United States)

    Miller, Meghan S.; Sun, Daoyuan; O'Driscoll, Leland; Becker, Thorsten W.; Holt, Adam; Diaz, Jordi; Thomas, Christine

    2015-04-01

    Detailed mantle and lithospheric structure from the Canary Islands to Iberia have been imaged with data from recent temporary deployments and select permanent stations from over 300 broadband seismometers. The stations extended across Morocco and Spain as part of the PICASSO, IberArray, and Morocco-Münster experiments. We present results from S receiver functions (SRF), shear wave splitting, waveform modeling, and geodynamic models that help constrain the tectonic evolution of the westernmost Mediterranean, including orogenesis of the Atlas Mountains and occurrence of localized alkaline volcanism. Our receiver function images, in agreement with previous geophysical modeling, show that the lithosphere is thin (~65 km) beneath the Atlas, but thickens (~100 km) over a very short length scale at the flanks of the mountains. We find that these dramatic changes in lithospheric thickness also correspond to dramatic decreases in delay times inferred from S and SKS splitting observations of seismic anisotropy. Pockets and conduits of low seismic velocity material below the lithosphere extend along much of the Atlas to Southern Spain and correlate with the locations of Pliocene-Quaternary magmatism. Waveform analysis from the USC linear seismic array across the Atlas Mountains constrains the position, shape, and physical characteristics of one localized, low velocity conduit that extends from the uppermost mantle (~200 km depth) up to the volcanoes in the Middle Atlas. The shape, position and temperature of these seismically imaged low velocity anomalies, topography of the base of the lithosphere, morphology of the subducted slab beneath the Alboran Sea, position of the West African Craton and correlation with mantle flow inferred from shear wave splitting suggest that the unusually high topography of the Atlas Mountains and isolated recent volcanics are due to active mantle support that may be from material channeled from the Canary Island plume.

  15. Numerical simulation of explosive volcanic eruptions from the conduit flow to global atmospheric scales

    Directory of Open Access Journals (Sweden)

    G. G. J. Ernst

    2005-06-01

    Full Text Available Volcanic eruptions are unsteady multiphase phenomena, which encompass many inter-related processes across the whole range of scales from molecular and microscopic to macroscopic, synoptic and global. We provide an overview of recent advances in numerical modelling of volcanic effects, from conduit and eruption column processes to those on the Earth s climate. Conduit flow models examine ascent dynamics and multiphase processes like fragmentation, chemical reactions and mass transfer below the Earth surface. Other models simulate atmospheric dispersal of the erupted gas-particle mixture, focusing on rapid processes occurring in the jet, the lower convective regions, and pyroclastic density currents. The ascending eruption column and intrusive gravity current generated by it, as well as sedimentation and ash dispersal from those flows in the immediate environment of the volcano are examined with modular and generic models. These apply simplifications to the equations describing the system depending on the specific focus of scrutiny. The atmospheric dispersion of volcanic clouds is simulated by ash tracking models. These are inadequate for the first hours of spreading in many cases but focus on long-range prediction of ash location to prevent hazardous aircraft - ash encounters. The climate impact is investigated with global models. All processes and effects of explosive eruptions cannot be simulated by a single model, due to the complexity and hugely contrasting spatial and temporal scales involved. There is now the opportunity to establish a closer integration between different models and to develop the first comprehensive description of explosive eruptions and of their effects on the ground, in the atmosphere, and on the global climate.

  16. Theory and modelling of quench in cable-in-conduit superconducting magnets

    International Nuclear Information System (INIS)

    A new simple, self consistent theoretical model is presented that describes the phenomena of quench propagation in Cable-In-Conduit superconducting magnets. The model (Quencher) circumvents many of the difficulties associated with obtaining numerical solutions in more general existing models. Specifically, a factor of 30-50 is gained in CPU time over the general, explicit time dependent codes used to study typical quench events. The corresponding numerical implementation of the new model is described and the numerical results are shown to agree very well with those of the more general models, as well as with experimental data. Further, well justified approximations lead to the MacQuench model that is shown to be very accurate and considerably more efficient than the Quencher model. The MacQuench code is suitable for performing quench studies on a personal computer, requiring only several minutes of CPU time. In order to perform parametric studies on new conductor designs it is required to utilize a model such as MacQuench because of the high computational efficiency of this model. Finally, a set of analytic solutions for the problem of quench propagation in Cable-In-Conduit Conductors is presented. These analytic solutions represent the first such results that remain valid for the long time scales of interest during a quench process. The assumptions and the resulting simplifications that lead to the analytic solutions are discussed, and the regimes of validity of the various approximations are specified. The predictions of the analytic results are shown to be in very good agreement with numerical as well as experimental results. Important analytic scaling relations are verified by such comparisons, and the consequences of some of these scalings on currently designed superconducting magnets are discussed

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

    Science.gov (United States)

    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.

  18. Rise of a variable-viscosity fluid in a steadily spreading wedge-shaped conduit with accreting walls

    Science.gov (United States)

    Lachenbruch, Arthur H.; Nathenson, Manuel

    1976-01-01

    Relatively rigid plates making up the outer 50 to 100 km of the Earth are steadily separating from one another along narrow globe-circling zones of submarine volcanism, the oceanic spreading centers. Continuity requires that the viscous underlying material rise beneath spreading centers and accrete onto the steadily diverging plates. It is likely that during the rise the viscosity changes systematically and that the viscous tractions exerted on the plates contribute to the unique pattern of submarine mountains and earthquake faults observed at spreading centers. The process is modeled by viscous creep in a wedge-shaped conduit (with apex at the sea floor) in which the viscosity varies as rm where r is distance from the apex and m is a parameter. For these conditions, the governing differential equations take a simple form. The solution for the velocity is independent of r and of the sign of m. As viscous stresses vary as rm-1, the pattern of stress on the conduit wall is sensitive to viscosity variation. For negative m, the viscous pressure along the base of the conduit is quite uniform; for positive m, it falls toward zero in the axial region as the conduit base widens. For small opening angles, viscous forces push the plates apart, and for large ones, they oppose plate separation. Though highly idealized, the solution provides a tool for investigating tectonic processes at spreading centers.

  19. Conduit fragmentation, cave patterns, and the localization of karst ground water basins: the Appalachians as a test case

    Directory of Open Access Journals (Sweden)

    White,W.B.

    2003-01-01

    Full Text Available Because conduit systems in maturely developed karst aquifers have a low hydraulic resistance, aquifers drain easily and karst aquifers are subdivided into well-defined ground water basins. Ground water elevations are highest at basin boundaries; lowest at the spring where the ground water is discharged. Parameters that control the type of conduit development are (1 the effective hydraulic gradient, (2 the focus of the drainage basin, and (3 the karstifiability of the bedrock. Moderate to highly effective hydraulic gradients permit the runaway process that leads to single conduit caves and well ordered branchwork systems. Low hydraulic gradients allow many alternate flow paths and thus a large degree of fuzziness in the basin boundaries. Low gradient ground water basins also tend to merge due to rising water tables during periods of high discharge. Focus is provided by geological constraints that optimize discharge at specific locations that can evolve into karst springs. Karstifiability is a measure of the bulk rate at which aquifer rocks will dissolve. Fine grained, pure limestones and shaley dolomites mark the opposite ends of the range. The cave surveys of the Appalachian Highlands provide a data base that can be used to classify the lateral arrangements of conduit systems and thus determine the relative importance of the factors defined above.

  20. FATIGUE PROPERTIES OF MODIFIED 316LN STAINLESS STEEL AT 4 K FOR HIGH FIELD CABLE-IN-CONDUIT APPLICATIONS

    International Nuclear Information System (INIS)

    Cable-In-Conduit-Conductor (CICC) alloys, exposed to Nb3Sn reaction heat-treatments, such as modified 316LN require a design specific database. A lack of fatigue life data (S-n curves) that could be applied in the design of the ITER CS and the NHMFL Series Connected Hybrid magnets is the impetus for the research presented here. The modified 316LN is distinguished by a lower carbon content and higher nitrogen content when compared to conventional 316LN. Because the interstitial alloying elements affect the mechanical properties significantly, it is necessary to characterize this alloy in a systematic way. In conjunction, to ensure magnet reliability and performance, several criteria and expectations must be met, including: high fatigue life at the operating stresses, optimal stress management at cryogenic temperatures and thin walled conduit to reduce coil mass. Tension-tension load control axial fatigue tests have good applicability to CICC solenoid magnet design, thus a series of 4 K strength versus fatigue life curves have been generated. In-situ samples of 316LN base metal, seam welded, butt welded and seam plus butt welded are removed directly from the conduit in order to address base and weld material fatigue life variability. The more than 30 fatigue tests show good grouping on the fatigue life curve and allow discretionary 4 K fatigue life predictions for conduit made with modified 316LN.

  1. Terrestrial analogs to lunar sinuous rilles - Kauhako Crater and channel, Kalaupapa, Molokai, and other Hawaiian lava conduit systems

    International Nuclear Information System (INIS)

    Two source vents, one explosive and one effusive erupted to form a cinder cone and low lava shield that together compose the Kalaupapa peninsula of Molokai, Hawaii, A 50-100-m-wide channel/tube system extends 2.3 km northward from kauhako crater in the center of the shield. Based on modeling, a volume of up to about 0.2 cu km of lava erupted at a rate of 260 cu m/sec to flow through the Kauhako conduit system in one of the last eruptive episodes on the peninsula. Channel downcutting by thermal erosion occurred at a rate of about 10 micron/sec to help form the 30-m-deep conduit. Two smaller, secondary tube systems formed east of the main lava channel/tube. Several other lava conduit systems on the islands of Oahu and Hawaii were also compared to the Kauhako and lunar sinuous rille systems. These other lava conduits include Whittington, Kupaianaha, and Mauna Ulu lava tubes. Morphologically, the Hawaiian tube systems studied are very similar to lunar sinuous rilles in that they have deep head craters, sinuous channels, and gentle slopes. Thermal erosion is postulated to be an important factor in the formation of these terrestrial channel systems and by analogy is inferred to be an important process involved in the formation of lunar sinuous rilles. 28 refs

  2. Nucleation stage in supersaturated vapor with inhomogeneities due to nonstationary diffusion onto growing droplets

    Science.gov (United States)

    Kuchma, Anatoly; Markov, Maxim; Shchekin, Alexander

    2014-05-01

    An analytical description of the nucleation stage in a supersaturated vapor with instantly created supersaturation is given with taking into account the vapor concentration inhomogeneities arising as a result of depletion due to nonstationary diffusion onto growing droplets. This description is based on the fact, that the intensity of the nucleation of new droplets is suppressed in spherical diffusion regions of a certain size surrounding previously nucleated droplets, and remains at the initial level in the remaining volume of the vapor-gas medium. The value of the excluded volume (excluded from nucleation) depends on the explicit form of the vapor concentration profile in the space around the growing droplet, and we use for that the unsteady self-similar solution of the time-dependent diffusion equation with a convective term describing the flow of the gas-vapor mixture caused by the moving surface of the single growing droplet. The main characteristics of the phase transition at the end of the nucleation stage are found and compared with those in the theory of nucleation with homogeneous vapor consumption (the theory of mean-field vapor supersaturation). It is shown that applicability of the mean-field approach depends on smallness of the square root of the ratio of the densities of metastable and stable phases. With increasing the temperature of the supersaturated vapor or for liquid or solid solutions, this smallness weakens, and then it would be more correct to use the excluded volume approach.

  3. An AMTEC vapor-vapor, series connected cell

    Science.gov (United States)

    Underwood, Mark L.; Williams, Roger M.; Ryan, Margaret A.; Jefferies-Nakamura, Barbara; O'Connor, Dennis

    1992-01-01

    The alkali metal thermal-to-electric converter (AMTEC) converts heat energy to electrical energy with efficiencies up to 3 to 4 times the state of the art static converters. However, the high current, low voltage output of a single module requires difficult series connecting of cells, and several life limiting concerns may reduce the achievable efficiency. A concept is proposed that incorporates internal series connecting of cells and sodium supply as a vapor without condensation. This concept overcomes many of the long term materials concerns in liquid anode systems and results in a module with about the same power density, but at a higher voltage and lower current. The vapor-vapor AMTEC concept is described and its performance predicted for typical AMTEC operating conditions.

  4. 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

    Scientific Electronic Library Online (English)

    Fernando Antônio, Fantini; Bayard, Gontijo Filho; Martins, Cristiane; Roberto Max, Lopes; Maria G, Horta; Leonardo F, Drumond; Marcelo Frederico de, Castro; Carla, Oliveira; Arturo, Ferrufino; João Alfredo de Paula e, Silva; Eduardo, Peredo; Juscelino Teixeira, Barbosa; Mário O, Vrandecic.

    1996-09-01

    Full Text Available A reconstrução biventricuiar de uma série de cardiopatias congênitas requer a interposição de condutos valvados ventrículo-arteriais. Com o objetivo de analisar a evolução a longo prazo de um conduto de pericárdio bovino valvulado com bíoprótese porcina sem suporte tratado com glutaraldeído, foram r [...] evistos os prontuários de 33 pacientes operados de novembro de 1985 a outubro de 1995. A idade variou de 15 dias a 18 anos (média 5,7 ± 4,3 anos). A atresia pulmonar com comunicação interventricular (CIV) foi a lesão mais freqüente (16 casos), seguida da síndrome da valva pulmonar ausente (5), truncus arteriosus (4), transposição das grandes artérias com CIV e estenose pulmonar (3) e outras (5). A mortalidade imediata foi de 18,2%, diretamente relacionada à condição pré-operatória. Vinte e três (70%) pacientes foram acompanhados por períodos que variaram de 3 meses a 10 anos (média 4,8 ± 3,0 anos). A complicação mais freqüentemente observada no seguimento tardio foi a estenose da anastomose distai do conduto, presente em 17,4% (4/23) dos pacientes. Foram reoperados 3 (13%) pacientes, sendo que 2 deles por estenose distal (p=0,02) e 1 por endocardite tardia do conduto. A mortalidade tardia foi de 17,4% (4/23), em 1 caso devido a estenose distai. A causa da estenose distal parece ser devida a retração tecidual na área de transição entre o pericárdio bovino e o tronco pulmonar. Em até 10 anos de seguimento não ocorreu calcificação significativa que prejudicasse a função tanto da valva quanto do conduto. Em conclusão, os condutos de pericárdio bovino apresentaram uma performance satisfatória como substitutos vasculares, não tendo ocorrido calcificação significativa da valva porcina ou das paredes do conduto no seguimento tardio. A incidência de estenose na anastomose distal parece estar mais relacionada a um fenômeno de retração tecidual do que a problemas técnicos. Abstract in english The biventricular repair of congenital heart 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 por [...] cine 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.

  5. Production of Seismic Radiation By Top Down Excitation of a Magmastatic Column: The Role of Non-Equilibrium Degassing and Complex Conduit Geometry

    Science.gov (United States)

    Karlstrom, L.; Dunham, E. M.

    2014-12-01

    Strong variation of multiphase fluid properties and conduit geometry with depth are defining characteristics of magmatic conduits. This background stratification has important implications for the excitation and propagation of waves through conduits, and the coupling of these fluid motions to the surroundings to produce seismic and infrasonic radiation. We develop a spectral and time domain numerical method to study perturbations to a basaltic magmastatic column, including non-equilibrium degassing and conduit width changes with depth, with a free top surface to model an active lava lake. We show that resonant modes of such a conduit to first order reflect the total magma water content, which sets the depth of volatile exsolution. Above the exsolution depth, wave propagation through the multiphase fluid is strongly dispersive, due to gas exsolution effects at periods greater than the time scale for exsolution and gravitational restoring forces at wavelengths greater than the scale height. We also find a class of nonpropagating and highly attenuated modes. Due to background stratification, wave modes are localized spatially around the depth of exsolution. Below this depth, waves propagate at the pure fluid sound speed, which may be nearly two orders of magnitude faster than the multiphase sound speed. We have also extended our model to couple waves in conduits to dikes and sills branching off of the conduit. This coupled model matches fluid pressure at the fracture mouth and accounts for mass exchange between the fracture and the conduit. It can be used to investigate how waves propagating down the conduit can excite resonant oscillation of dikes and sills as has been inferred in, for example, the shallow plumbing system at Kilauea, HI, where Very Long Period (VLP) seismic signals have been commonly although episodically observed since 2007. These signals commonly have source depths around 1 km depths, where source mechanisms suggest a sill intersects the conduit, but likely are triggered near the surface from some combination of degassing or rockfall that excites conduit resonant modes. We will explore the importance both of this coupled sill-conduit geometry, and of conduit modes localized at the water exsolution depth, on the seismic wave field generated by near surface fluid excitation of a magmastatic column.

  6. Water vapor measurements in- and outside cirrus with the novel water vapor mass spectrometer AIMS-H2O

    Science.gov (United States)

    Kaufmann, Stefan; Schlage, Romy; Voigt, Christiane; Jurkat, Tina; Krämer, Martina; Rolf, Christian; Zöger, Martin; Schäfler, Andreas; Dörnbrack, Andreas

    2015-04-01

    Water vapor plays a crucial role for the earth's climate both directly via its radiative properties and indirectly due to its ability to form clouds. However, accurate measurements of especially low water vapor concentrations prevalent in the upper troposphere and lower stratosphere are difficult and exhibit large discrepancies between different instruments and methods. In order to address this issue and to provide a comprehensive water vapor data set necessary to gather a complete picture of cloud formation processes, four state-of-the-art hygrometers including the novel water vapor mass spectrometer AIMS-H2O were deployed on the DLR research aircraft HALO during the ML-Cirrus campaign in March/April 2014 over Europe. Here, we present first water vapor measurements of AIMS-H2O on HALO. The instrument performance is validated by intercomparison with the fluorescence hygrometer FISH and the laser hygrometer SHARC, both also mounted in the aircraft. This intercomparison shows good agreement between the instruments from low stratospheric mixing ratios up to higher H2O concentrations at upper tropospheric conditions. Gathering data from over 24 flight hours, no significant offsets between the instruments were found (mean of relative deviation

  7. Fabrication of bioactive conduits containing the fibroblast growth factor 1 and neural stem cells for peripheral nerve regeneration across a 15 mm critical gap

    International Nuclear Information System (INIS)

    Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan–nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve. (paper)

  8. Long-term efficacy and safety outcomes of transplantation of induced pluripotent stem cell-derived neurospheres with bioabsorbable nerve conduits for peripheral nerve regeneration in mice.

    Science.gov (United States)

    Uemura, Takuya; Ikeda, Mikinori; Takamatsu, Kiyohito; Yokoi, Takuya; Okada, Mitsuhiro; Nakamura, Hiroaki

    2014-01-01

    The induced pluripotent stem cell (iPSc) offers great potential for cell-based therapy in regenerative medicine. We previously developed tissue-engineered bioabsorbable nerve conduits coated with iPSc-derived neurospheres for use in peripheral nerve repair. Here, we examine the long-term efficacy and safety of using nerve conduits with iPSc technology for peripheral nerve repair in mice. The nerve conduit consisted of an outer layer of a poly L-lactide mesh and an inner layer of porous sponge composed of 50% L-lactide and 50% ?-caprolactone. Secondary neurospheres were derived from mouse iPScs, resuspended and cultured within the conduit for 14 days. Conduits were implanted within surgically administered 5-mm defects in the left sciatic nerve of mice (iPSc group; n = 14). The defects in the control group (n = 13) were reconstructed using the nerve conduit alone. At 4, 8, 12, 24 and 48 weeks postsurgery, motor and sensory functional recovery in the iPSc group had improved significantly more than in the control group. At 24 and 48 weeks, histological analysis revealed axonal regeneration in the nerve conduits of both groups. However, axonal regeneration and myelination were significantly enhanced in the iPSc group. No teratomas were identified in the iPSc group at any time point. Therefore, we here demonstrate that bioabsorbable nerve conduits coated with iPSc-derived neurospheres promote enhanced regeneration of peripheral nerves and functional recovery without teratoma formation in the long term. This combination of iPSc technology and bioabsorbable nerve conduits has the potential to be a safe future tool for the treatment of peripheral nerve defects. © 2015 S. Karger AG, Basel. PMID:25823624

  9. Absorption of tritiated water vapor from the atmosphere by the needles of pine trees

    International Nuclear Information System (INIS)

    One means of tritium absorption into an ecosystem is the diffusion of tritiated water vapor into tree needles where it becomes part of the plant water supply. The mechanisms by which absorption of tritiated water vapor takes place were studied with two slash pine trees: Pinus elliotii Engelm. Three branches on each tree were enclosed in clear plastic bags, and three branches on each tree were enclosed in double, dark green bags. Forty ml of water containing 15.7 nCi/ml of tritium were placed in the bottom of each bag. The foliage was not exposed directly to the water, so that all absorption would take place in the vapor phase. An analysis of the uptake rates indicates that tritiated water vapor diffuses into the foliage by the same pathways as water vapor diffuses out of the foliage and rapidly becomes mixed with the bulk of the leaf water

  10. Waste Tank Vapor Project: Tank vapor database development

    International Nuclear Information System (INIS)

    The objective of the Tank Vapor Database (TVD) Development task in FY 1994 was to create a database to store, retrieve, and analyze data collected from the vapor phase of Hanford waste tanks. The data needed to be accessible over the Hanford Local Area Network to users at both Westinghouse Hanford Company (WHC) and Pacific Northwest Laboratory (PNL). The data were restricted to results published in cleared reports from the laboratories analyzing vapor samples. Emphasis was placed on ease of access and flexibility of data formatting and reporting mechanisms. Because of time and budget constraints, a Rapid Application Development strategy was adopted by the database development team. An extensive data modeling exercise was conducted to determine the scope of information contained in the database. a A SUN Sparcstation 1000 was procured as the database file server. A multi-user relational database management system, Sybase reg-sign, was chosen to provide the basic data storage and retrieval capabilities. Two packages were chosen for the user interface to the database: DataPrism reg-sign and Business Objects trademark. A prototype database was constructed to provide the Waste Tank Vapor Project's Toxicology task with summarized and detailed information presented at Vapor Conference 4 by WHC, PNL, Oak Ridge National Laboratory, and Oregon Graduate Institute. The prototype was used to develop a list of reported compounds, and the range of values for compounds reported by the analytical laboratories using different sample containers and analysis methodologies. The prototype allowed a panel of toxicology experts to identify carcinogens and compounds whose concentrations were within the reach of regulatory limits. The database and user documentation was made available for general access in September 1994

  11. Experimental composite guidance conduits for peripheral nerve repair: An evaluation of ion release

    International Nuclear Information System (INIS)

    Poly (lactide-co-glycolide) (PLGA) — Pluronic F127 — glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si4+, Ca2+, Na+, Zn2+, and Ce4+ from experimental composite nerve guidance conduits (CNGC) comprising PLGA (at 12.5, and 20 wt.%), F127 (at 0, 2.5 and 5 wt.%) and various loadings of Si–Ca–Na–Zn–Ce glass (at 20 and 40 wt.%) for incubation periods of up to 28 days. The concentration of each ion, at various time points, was determined using Inductively Coupled Plasma–Atomic Emission Spectrometry (Perkin Elmer Optima 3000). It was observed that the Si4+, Na+, Ca2+, Zn2+ release from CNGCs in this study ranged from 0.22 to 6.477 ppm, 2.307 to 3.277 ppm, 40 to 119 ppm, and 45 to 51 ppm, respectively. The Ce4+ concentrations were under the minimum detection limits for the um detection limits for the ICP instrument utilized. The results indicate that the ion release levels may be appropriate to mediate therapeutic effects with respect to peripheral nerve regeneration. The data generated in this paper provides requisite evidence to optimize composition for pre-clinical evaluation of the experimental composite. - Graphical abstract: Highlights: ? Time-dependent degradation studies of PLGA/glass composite nerve guidance conduits (NGCs). ? Si4+, Na+, Ca2+ and Zn2+ release levels for the glass containing NGCs are presented. ? Release levels may mediate therapeutic effects to provoke nerve regeneration. ? Data provides requisite evidence to optimize composition to pre-clinical requirements.

  12. Stability experimental results of cable-in-conduit superconductor for fusion

    International Nuclear Information System (INIS)

    In case of the forced-flow cooling, the design basis should be established regarding the stability, the static pressure drop and the transient pressure rise during quench which are more serious than that of the pool-boiling cooling coils by liquid helium. For this purpose, JAERI constructed a 15-kA cable-in-conduit conductor whose major parameters is based on a real conductor of FER and measured the stability, the pressure drop, and the pressure rise characteristics by using the Superconducting Engineering Test Facility (SETF). The following conclusions are obtained by this experiments in which a disturbance is applied to a part of the conductor by an inductive heater for a heating time duration of 6 msec. 1) Two types of quench, which are quench at the heated zone and at the down stream region, are observed and the down stream quench is serious for the forced-flow cooling coils because the down stream quench is caused by a lesser disturbance than the heated zone. 2) The heated zone conductor is cooled by a transient heat transfer and an induced flow which give a higher cooling capability than the steady flow in the down stream region. The calculated stability characteristics by an analysis code ''ALPHE-II'' are in good agreement with the measured value. 3) The down stream quench is caused by hot helium flowing from the heated zone to the down stream and the stability margin measured is in good agreement with the calculated value by a simple energy balance based on the quasi-static process. 4) The friction factor of a cable-in-conduit conductor has a smooth slope and is in good agreement with the equation for turbulent flow. In addition, the friction factor is roughly twice that of a smooth tube. 5) The pressure rise obtained in a full quench condition is in good agreement with the calculated value by the ALPHE-II and linearly increases as the heating energy to the helium is increased. (author)

  13. Experimental composite guidance conduits for peripheral nerve repair: An evaluation of ion release

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.F. [Department of Biological Sciences and Medical Engineering Design and Innovation Centre, Cork Institute of Technology, Cork (Ireland); Coughlan, A. [Inamori School of Engineering, Alfred University, Alfred, NY. 14802 (United States); O' Shea, H. [Department of Biological Sciences and Medical Engineering Design and Innovation Centre, Cork Institute of Technology, Cork (Ireland); Towler, M.R. [Inamori School of Engineering, Alfred University, Alfred, NY. 14802 (United States); Kehoe, S., E-mail: sharonkehoe@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); Boyd, D., E-mail: d.boyd@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 4R2 (Canada)

    2012-08-01

    Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si{sup 4+}, Ca{sup 2+}, Na{sup +}, Zn{sup 2+}, and Ce{sup 4+} from experimental composite nerve guidance conduits (CNGC) comprising PLGA (at 12.5, and 20 wt.%), F127 (at 0, 2.5 and 5 wt.%) and various loadings of Si-Ca-Na-Zn-Ce glass (at 20 and 40 wt.%) for incubation periods of up to 28 days. The concentration of each ion, at various time points, was determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (Perkin Elmer Optima 3000). It was observed that the Si{sup 4+}, Na{sup +}, Ca{sup 2+}, Zn{sup 2+} release from CNGCs in this study ranged from 0.22 to 6.477 ppm, 2.307 to 3.277 ppm, 40 to 119 ppm, and 45 to 51 ppm, respectively. The Ce{sup 4+} concentrations were under the minimum detection limits for the ICP instrument utilized. The results indicate that the ion release levels may be appropriate to mediate therapeutic effects with respect to peripheral nerve regeneration. The data generated in this paper provides requisite evidence to optimize composition for pre-clinical evaluation of the experimental composite. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer Time-dependent degradation studies of PLGA/glass composite nerve guidance conduits (NGCs). Black-Right-Pointing-Pointer Si{sup 4+}, Na{sup +}, Ca{sup 2+} and Zn{sup 2+} release levels for the glass containing NGCs are presented. Black-Right-Pointing-Pointer Release levels may mediate therapeutic effects to provoke nerve regeneration. Black-Right-Pointing-Pointer Data provides requisite evidence to optimize composition to pre-clinical requirements.

  14. Étude des perturbations conduites et rayonnées dans une cellule de commutation

    Science.gov (United States)

    Costa, F.; Forest, F.; Puzo, A.; Rojat, G.

    1993-12-01

    The principles used in static conversion and the rise of the performances of the new switching devices contribue to increase the level of electromagnetic noises emitted by electronic converters. We have studied the way how these perturbations are created and coupled through their environment in conducted and radiated mode by a switching cell. This one can work in hard switching, zero current or voltage switching modes. We first outline the general problems of electromagnetic pollution and their metrology in converters. Then we describe the experimental environment. We analyse the mechanisms of generation of parasitic signals in a switching cell related to the electrical constraints and its switching mode. The simulated results, issued of the analytical models obtained, are confronted with the experimental ones. Then we show a method to calculate analytically the E and H near fields. It has been confirmed by experimental results. At last, we present, in a synthetic manner, the main results obtained, relative to the switching mode and the electrical constraints, using a new characterizing method. Theses results will allow the designer to incorporate the electromagnetic considerations in the conception of a converter. Les principes de commutation employés en conversion statique, l'évolution des performances statiques et dynamiques des composants, contribuent à faire des dispositifs de conversion statique de puissants générateurs de perturbations conduites et rayonnées. Nous nous sommes attachés à étudier les mécanismes de génération et de couplage des perturbations, tant en mode conduit que rayonné dans des structures à une seule cellule de commutation et fonctionnant selon les trois principaux modes de commutation : commutation forcée, à zéro de courant (ZCS), et à zéro de tension (ZVS). Après la mise en évidence de la problématique de pollution électromagnétique dans les structures et leur métrologie, nous décrivons l'environnement expérimental étudié. Nous analysons ensuite les principaux mécanismes produisant les perturbations au sein d'une cellule de commutation en introduisant un certain nombre de composants parasites. Les modèles sont simulés et confrontés aux résultats expérimentaux. Nous décrivons alors une méthode, validée expérimentalement et permettant de calculer les intensités des champs E et H proches émis. Enfin, nous présentons de façon synthétique les résultats observés selon les régimes de fonctionnement de la cellule de commutation et les contraintes électriques et dynamiques qu'elle subit. Nous avons, pour ce faire, développé une méthode originale de quantification des signaux perturbateurs. Les résultats obtenus doivent permettre d'intégrer les problèmes de pollution électromagnétique au stade de la conception d'un dispositif.

  15. Role of nearest-neighbor drops in the kinetics of homogeneous nucleation in a supersaturated vapor

    Science.gov (United States)

    Grinin, A. P.; Zhuvikina, I. A.; Kuni, F. M.; Reiss, H.

    2004-12-01

    A theory of simultaneous nucleation and drop growth in a supersaturated vapor is developed. The theory makes use of the concept of "nearest-neighbor" drops. The effect of vapor heterogeneity caused by vapor diffusion to a growing drop, formed previously, is accounted for by considering the nucleation of the nearest-neighbor drop. The diffusional boundary value problem is solved through the application of a recent theory that maintains material balance between the vapor and the drop, even though the drop boundary is a moving one. This is fundamental to the use of the proper time and space dependent vapor supersaturation in the application of nucleation theory. The conditions are formulated under which the mean distance to the nearest-neighbor drop and the mean time to its appearance can be determined reliably. Under these conditions, the mean time provides an estimate of the duration of the nucleation stage, while the mean distance provides an estimate of the number of drops formed per unit volume during the nucleation stage. It turns out, surprisingly, that these estimates agree fairly well with the predictions of the simpler and more standard approach based on the approximation that the density of the vapor phase remains uniform during the nucleation stage. Thus, as a practical matter, in many situations, the use of the simpler and less rigorous method is justified by the predictions of the more rigorous, but more complicated theory.

  16. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    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…

  17. Hanford soil partitioning and vapor extraction study

    International Nuclear Information System (INIS)

    This report describes the testing and results of laboratory experiments conducted to assist the carbon tetrachloride soil vapor extraction project operating in the 200 West Area of the Hanford Site in Richland, Washington. Vapor-phase adsorption and desorption testing was performed using carbon tetrachloride and Hanford Site soils to estimate vapor-soil partitioning and reasonably achievable carbon tetrachloride soil concentrations during active vapor extractions efforts at the 200 West Area. (CCl4 is used in Pu recovery from aqueous streams.)

  18. Effect of chrome plating on coupling losses in a Nb3Sn cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Time constant of decay of coupling current was measured on cable-in-conduit conductors which consist of twelve Nb3Sn strands with chrome plating. The time constant measurement was performed by observing exponential decrease of induced coupling current in conductors. The measured time constant of conductor composed of bare strands was 4.5 times larger than that of the single strand, in case that a void fraction of conductor was 30%. However, the time constant of conductor composed of strands with chrome plating of more than 2 ?m thickness was equal to that of the single strand. These results show that chrome plating on strands is effective for decrease of coupling losses in Nb3Sn cable-in-conduit conductors. (author)

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

    Science.gov (United States)

    Delage, Elise; Zurzolo, Chiara

    2013-01-01

    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. PMID:24368909

  20. Microgravity techniques for the characterisation of conduit flow in Karstic terrains

    Science.gov (United States)

    Styles, P.; McGrath, R.; Bate, D.

    2003-04-01

    In Karstic terrains, groundwater flow may occur in joints or fissures enlarged by dissolution or in subterranean rivers in cave systems. In such areas groundwater contamination either from inorganic or organic sources may rapidly enter and travel through the system. When quarrying occurs in limestone regions the dewatering may lead to depression of the water table well below the natural piezometric surface. Extraction may penetrate depths well below the water table and contaminant spills or criminal waste disposal in these quarries may lead to subsequent contamination on groundwater recovery, post closure. The microgravity technique has the potential to identify, delineate and characterise cavities which may act as conduits and provide targets for confirmatory drilling or as entry points for dye-tracing and sampling. Additional information from drilling or some other geophysical technique such as resistivity imaging can allow detailed configurations of the subsurface cavity to be derived from inversion techniques. Case studies are shown here from Coralgal limestone on Grand Bahama, Carboniferous Limestone in South Wales (UK) and on the Burren and Roscommon (Ireland). In all cases, ground truth was obtained by subsequent drilling. Changes in pore fluid density can also be identified using time-varying microgravity. 3-D modelling and field trials have shown that changes associated with the cyclic pressurisation and draw-down of a gas storage facility in sandstone can be detected. This technique has significant promise for monitoring Carbon Dioxide sequestration and secondary recovery in hydrocarbon reservoirs.

  1. Thermo-Hydraulic behaviour of dual-channel superconducting Cable-In-Conduit Conductors for ITER

    International Nuclear Information System (INIS)

    In an effort to optimise the cryogenics of large superconducting coils for fusion applications (ITER), dual channel Cable-In-Conduit Conductors (CICC) are designed with a central channel spiral to provide low hydraulic resistance and faster helium circulation. The qualitative and economic rationale of the conductor central channel is here justified to limit the superconductor temperature increase, but brings more complexity to the conductor cooling characteristics. The pressure drop of spirals is experimentally evaluated in nitrogen and water and an explicit hydraulic friction model is proposed. Temperatures in the cable must be quantified to guarantee superconductor margin during coil operation under heat disturbance and set adequate inlet temperature. Analytical one-dimensional thermal models, in steady state and in transient, allow to better understand the thermal coupling of CICC central and annular channels. The measurement of a heat transfer characteristic space and time constants provides cross-checking experimental estimations of the internal thermal homogenization. A simple explicit model of global inter-channel heat exchange coefficient is proposed. The risk of thermosyphon between the two channels is considered since vertical portions of fusion coils are subject to gravity. The new hydraulic model, heat exchange model and gravitational risk ratio allow the thermohydraulic improvement of CICC central spirals. (author)

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

    Science.gov (United States)

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

    2014-06-01

    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.

  3. Normal zone propagation and Thermal Hydraulic Quenchback in a cable-in-conduit superconductor

    International Nuclear Information System (INIS)

    When a local normal zone appears in a cable-in-conduit superconductor, a slug of hot helium is produced. The pressure rises and the hot helium expands. Thus the normal zone propagation in such a conductor can be governed by the hot helium expansion, rather than the heat conduction along the conductor. The expansion of the hot helium compresses the cold helium outside of the normal zone. This raises th at sign temperature of the cold helium. When the temperature rise reaches the current sharing limit, the superconductor in contact goes normal. Thus a rapid increase in normal zone propagation occur. This phenomenon is termed Thermal Hydraulic Quenchback (THQ). An experiment was performed to investigate this process. The existence of THQ was verified. Thresholds of THQ were also observed by varying the conductor current, the magnetic field, the temperature, and the initial normal zone length. When THQ occurred, normal zone propagation approaching the velocity of sound was observed. A better picture of THQ is obtained by a careful comparison of the data with analytical studies

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

    LENUS (Irish Health Repository)

    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.

  5. Assessment of moulin head variations and subglacial conduit connectivity in the Greenland ablation zone

    Science.gov (United States)

    Nowinski, J. D.; Catania, G. A.; Andrews, L. C.; Gulley, J. D.; MacGregor, J. A.; Hawley, R. L.; Hoffman, M. J.; Luethi, M. P.; Neumann, T.

    2012-12-01

    One of the remaining challenges in predicting future ice sheet mass balance is to understand how ice sheet velocities respond to increasing meltwater supply in a system with dynamic subglacial channels. Moulins represent a potentially important component of this system because they convey large amounts of surface melt into the ice sheet, potentially in locations with subglacial conduits, yet it is poorly understood how this input influences spatiotemporal variations in subglacial water pressure and ice sheet velocity. To help elucidate these links at the catchment scale (~5 km2), we deployed pressure sensors into four moulins in the ablation zone of western Greenland during the summer of 2012. To monitor changes in inputs into the moulins, stream gauges were also installed at each site. In addition, a GPS array was installed to monitor spatial variations in velocity and elevation. All four moulins display strong (~50-100 m) diurnal variations in hydraulic head that are well correlated to temperature and solar radiation. Further, the moulins comprise two pairs in which the moulins in each pair experience nearly identical and concurrent head fluctuations, despite having differing water inputs. This finding suggests that separate moulins may be connected englacially or subglacially over distances as large as 1.5 km or more.

  6. Collagen I and III and mechanical properties of conduit arteries in rats with genetic hypertension.

    Science.gov (United States)

    Chamiot Clerc, P; Renaud, J F; Blacher, J; Legrand, M; Samuel, J L; Levy, B I; Sassard, J; Safar, M E

    1999-01-01

    Conduit arteries of hypertensive rats are thicker and stiffer than those of normotensive controls. The possible role played by collagen type I and II subtypes in the mechanism of arterial stiffness remains unknown. The carotid and aortic arterial wall of rats of Japanese (Wistar-Kyoto and spontaneously hypertensive rats) and Lyon (normotensive and hypertensive rats) origin were studied. The stiffness of the carotid wall material (ultrasound), the histomorphometry of the aortic wall with the content in collagen I and III subtypes and their corresponding mRNA were analyzed. Independently of hypertension, the Japanese group differed from the Lyon group by a stiffer carotid wall material at any given value of wall stress; a lesser degree of aortic hypertrophy with a higher percentage of elastin, and a higher density of collagen III but not of collagen I. All other hemodynamic and histomorphometric parameters were affected by both the origin of the rats (Japanese vs. Lyon) and the presence of hypertension. Large artery stiffness in genetically hypertensive rats was not only influenced by hypertension itself, but also by differences in the contents of collagen subtypes which are also found in their corresponding normotensive controls. PMID:10213910

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. [Surgical treatment of a patient with giant false aneurysm of xenopericardial conduit of the ascending aorta].

    Science.gov (United States)

    Charchian, É R; Skvortsov, A A

    2015-01-01

    The article deals with a clinical case report concerning successful secondary surgical intervention for a giant pseudoaneurysm of the xenopericardial conduit of the ascending aorta in a patient with type A chronic aortic dissection, with a history previously endured prosthetic repair of the ascending aorta and aortic valve for acute dissection. The patient underwent was subjected to repeat prosthetic repair of the aortic valve and ascending aorta according to the Cabrol's technique. The postoperative period was uneventful. The function of the aortic valve prosthesis after surgery was satisfactory. The control multispiral computed tomography showed that reconstruction zone was without deformities, with the ostia of coronary arteries patent. On day 15 postoperatively the patient was discharged from hospital to undergo rehabilitation with recommendations concerning the subsequent stage of surgical treatment. The conclusion was drawn that despite life-threatening disease and an extensive scope of reconstruction correctly chosen surgical policy makes it possible to adequately carry out the necessary operation with a good outcome. PMID:25757183

  9. Local complications after harvesting of radial artery conduit for coronary artery bypass grafting: mayo hospital experience

    International Nuclear Information System (INIS)

    Objectives: To evaluate incidence of local complications of radial artery (RA) harvesting for coronary art-ery bypass grafting (CABG). Patients and Methods: From March 2011 to January 2012, a total of 87 consecutive patients fulfilling the inclusion and exclusion criteria, who underwent CA-BG and had left radial artery used as a conduit were included in this study. Prospective surveillance of surgical site (radial artery harvest site) was assessed on a daily basis during the patient's stay in the Department of Cardiac Surgery, Mayo Hospital / KEMU, Lahore and were reassessed after one month and six months interval. Surgical site assessment includes cutaneous paraesthesia, compartment syndrome, hand Ischemia, donor arm weakness, superficial infection, wound dehiscence, hematoma and impact of these complications on the quality of life. Results: During the study period 6 Patients (6.8%) reported cutaneous paraesthesia around the thenar eminence after 6 months; 3 Patients (3.4%) developed donor arm weakness, normalized after 6 months. Superficial wound infection and Hematoma (not requiring re-exploration) was noted in 1.1% and 2.9% respectively. None of the patients developed compartment syndrome, hand Ischemia, wound dehiscence. Conclusions: Findings confirm that the local complications after radial artery harvesting are rare and are clinically insignificant. (author)

  10. "Pit Craters", lava tubes, and open vertical volcanic conduits in Hawaii: a problem in terminology

    Directory of Open Access Journals (Sweden)

    William R. Halliday

    1998-01-01

    Full Text Available Almost from the 1849 publication of the term pit crater, volcanologists have disagreed about the parameters differentiating these features from other vertical volcanic structures. Kaluaiki is a jameo giving entry to Thurston Lava Tube in Hawaii Volcanoes National Park. Long-standing misidentification of it as a pit crater is an example of misunderstandings arising from the lack of a clear definition of pit crater. In general, pit craters are unrelated to lava tube caves genetically, but two special cases are discussed. One probably is genetically related to a rift tube deep below the surface; the other is a complex of a small pit crater with a partial rim of accreted plates plus an ordinary-seeming lava tube cave. The term pit crater should be redefined in such a way that it excludes collapses or subsidences related to ordinary superficial lava tubes and open vertical volcanic conduits. Otherwise, a non-definition like that currently listed for agglomerate may be appropriate.

  11. Three dimensional CFD analysis of Cable-in-Conduit Conductors (CICCs) using porous medium approach

    Science.gov (United States)

    Raja Sekhar, Dondapati; Rao, V. V.

    2013-02-01

    Thermohydraulic studies based on porous medium analogy, pertinent to dual channel Cable-in-Conduit Conductors (CICCs) used in International Thermonuclear Experimental Reactor (ITER), are explored in the present work. Dual channel CICC used in Toroidal Field (TF) Coil consists of a circular jacket in which superconducting cable bundles are placed in the annular channel separated from the central channel by a spiral. The cable bundle in the annular channel can be considered as saturated porous medium and the central channel can be viewed as clear region for thermohydraulic studies. In the present work, a 3D Computational Fluid Dynamics (CFD) analysis is performed on CICC by considering dual channel CICC as partially filled saturated porous medium. The 3D geometry was developed and meshed in GAMBIT-2.1.6, and exported to a commercial solver FLUENT -6.3.26 for further analysis. The effect of mass flow rate ( 6 - 10 g/s) of supercritical helium (SHe) on the velocity and pressure gradient distributions (axial and radial) in the transverse plane is presented. These studies resulted in estimating the mass flow repartition between the two channels and pumping power required to pump the SHe in CICC. In addition, the present CFD analysis brings a clear perspective of the phenomena of flow and heat transfer in complex geometries such as CICC.

  12. Evaluation of thermal gradients and thermosiphon in dual channel cable-in-conduit conductors

    Science.gov (United States)

    Renard, B.; Duchateau, J. L.; Rousset, B.; Tadrist, L.

    2006-09-01

    In an effort to optimize superconductor cryogenics of large coils, dual channel cable-in-conduit conductors (CICC) have been designed. The qualitative and economic rationale of the conductor central channel is here justified but brings high complexity to the conductor cooling characteristics. Temperature gradients in the cable must be quantified to guarantee conductor temperature margin during coil operation under heat disturbance and set adequate inlet temperature. A simple one-dimensional thermal model, with neither fluid nor strand or jacket conduction, allows to better understand and quantify the steady state behavior of CICC central and annular channels. This thermohydraulic model with homogeneous central and annular temperatures and no jacket conduction is summarized with explicit thermal coupling equations. Local convection coefficients chosen proportional to friction factors lead to a model of global interchannel heat exchange coefficient serving the bithermal model. A first stationary experimental evaluation of the internal heat transfer coefficient using the interchannel heat exchange space constant at various heat loads and mass flow rates is illustrated on two full size samples tested at cryogenic temperatures. Annular heaters experiments with low distributed power achieve pertinent model correlation. Discrepancy between model and experimental data may be linked to the simplistic homogeneous annular temperature hypothesis, to the estimate of CICC mass flow distribution among channels, and to gravitational effects at high heat loads. Perturbation due to the thermosiphon generated between the two channels is considered since neither the experiments nor the expected applications are free of gravity.

  13. Reverse saphenous conduit flap in small animals: Clinical applications and outcomes

    Scientific Electronic Library Online (English)

    Ross C., Elliott.

    2014-01-01

    Full Text Available Due to the lack of skin elasticity defects of the distal hind limb can be a challenge to close. This article assesses a well-described, but completely under-used technique for closure of wounds on the distal tarsus. The technique was used with good success in six cases presenting to the Bryanston Ve [...] terinary Hospital with a wide range of underlying pathology ranging from trauma to neoplastic disease of the tarsus. All six cases were treated with a reverse saphenous conduit flap and two of them underwent radiation therapy with no adverse side effects. All cases showed excellent results with a very low degree of flap necrosis that never exceeded 15% of the total flap area. This skin flap provides an excellent treatment method that is reliable in closure of defects of the distal tarsus with few adverse effects. To the author's knowledge there has been only one previously published report on the clinical use of this type of skin flap, even though the flap is well described in most texts.

  14. Reverse saphenous conduit flap in small animals: Clinical applications and outcomes

    Directory of Open Access Journals (Sweden)

    Ross C. Elliott

    2014-08-01

    Full Text Available Due to the lack of skin elasticity defects of the distal hind limb can be a challenge to close. This article assesses a well-described, but completely under-used technique for closure of wounds on the distal tarsus. The technique was used with good success in six cases presenting to the Bryanston Veterinary Hospital with a wide range of underlying pathology ranging from trauma to neoplastic disease of the tarsus. All six cases were treated with a reverse saphenous conduit flap and two of them underwent radiation therapy with no adverse side effects. All cases showed excellent results with a very low degree of flap necrosis that never exceeded 15% of the total flap area. This skin flap provides an excellent treatment method that is reliable in closure of defects of the distal tarsus with few adverse effects. To the author’s knowledge there has been only one previously published report on the clinical use of this type of skin flap,even though the flap is well described in most texts.

  15. Emissions of mercury vapor from tree bark

    Science.gov (United States)

    Hanson, Paul J.; Tabberer, Todd A.; Lindberg, Steven E.

    Measurements of the rate of elemental Hg vapor (Hg°) emissions from the bark of red maple ( Acer rubrum L.), yellow-poplar ( Liriodendron tulipifera L.), chestnut oak ( Quercus prinus L.) and white oak ( Quercus alba L.) were conducted in a controlled laboratory chamber with a mean air Hg° concentration of 1.6 ng m -3. Measured Hg° emissions for the four bark species studied ranged from a maximum of 10.8 ng m -2 h -1 for white oak to a minimum of 1.2 ng m -2 h -1 for red maple. Chestnut oak, yellow-poplar, and red maple bark all had similar Hg° emission rates with a mean of 1.9 ng m -2 h -1, but the mean emission rates from white oak were up to five times greater. This discrepancy was correlated with higher rates of evaporation from the white oak bark samples. When compared to published values of Hg° emissions from foliage and soils, it was concluded that bark surfaces would contribute less than 10% of all Hg° emissions from a forest landscape.

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

    OpenAIRE

    Dahl Ejby Jensen, Lasse; Cao, Renhai; Hedlund, Eva-maria; So?ll, Iris; Lundberg, Jon O.; Hauptmann, Giselbert; Steffensen, John Fleng; Cao, Yihai

    2009-01-01

    The blood and lymphatic vasculatures are structurally and functionally coupled in controlling tissue perfusion, extracellular interstitial fluids, and immune surveillance. Little is known, however, about the molecular mechanisms that underlie the regulation of bloodlymphatic vessel connections 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 hyp...

  17. Laboratory and numerical study of hyporheic flow in karst conduits and its effect on sediment-entrapped DNAPLs

    OpenAIRE

    Wu, Yuexia; Hunkeler, Daniel

    2013-01-01

    Contamination of karst aquifer, particularly by organic compounds, such as the Dense Non-aqueous Phase Liquids (DNAPLs) constitutes a threat for water supply and the environment. Due to the presence of large openings in karst systems and the high density of DNAPLs they may frequently reach conduits and accumulate at low points such as siphon structures that likely also contain sediments. Hence sediment-entrapped DNAPLs are commonly encountered and present as a continuous phase of organic liqu...

  18. Spatial analysis of karst conduit networks and determination of parameters controlling the speleogenesis along preferential lithostratigraphic horizons

    OpenAIRE

    Filipponi, Marco

    2009-01-01

    The main objective of this thesis is to improve the understanding of the position and characteristics of karst conduits within a rock massif. Such a characterisation is an important issue in civil engineering and in hydrogeology. Today in practice dissolution voids are considered as random in most cases. However, it is obvious for karst researchers that dissolution void distribution is not random, but defined by parameters controlling the speleogenesis. We developed a method to analyse the 3D...

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

    Science.gov (United States)

    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. PMID:23287534

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Seven days of aerobic exercise training improves conduit artery blood flow following glucose ingestion in patients with type 2 diabetes

    OpenAIRE

    Mikus, Catherine R.; Fairfax, Seth T.; Libla, Jessica L.; Boyle, Leryn J.; Vianna, Lauro C.; Oberlin, Douglas J.; Grace M. Uptergrove; Deo, Shekhar H.; Kim, Areum; Kanaley, Jill A.; Fadel, Paul J.; John P. Thyfault

    2011-01-01

    The vasodilatory effects of insulin account for up to 40% of insulin-mediated glucose disposal; however, insulin-stimulated vasodilation is impaired in individuals with type 2 diabetes, limiting perfusion and delivery of glucose and insulin to target tissues. To determine whether exercise training improves conduit artery blood flow following glucose ingestion, a stimulus for increasing circulating insulin, we assessed femoral blood flow (FBF; Doppler ultrasound) during an oral glucose toleran...

  2. Widening of xylem conduits in a conifer tree depends on the longer time of cell expansion downwards along the stem

    OpenAIRE

    Anfodillo, Tommaso; Deslauriers, Annie; Menardi, Roberto; Tedoldi, Laura; Petit, Giai; Rossi, Sergio

    2011-01-01

    The diameter of vascular conduits increases towards the stem base. It has been suggested that this profile is an efficient anatomical feature for reducing the hydraulic resistance when trees grow taller. However, the mechanism that controls the cell diameter along the plant is not fully understood. The timing of cell differentiation along the stem was investigated. Cambial activity and cell differentiation were investigated in a Picea abies tree (11.5 m in height) collecting microsamples at n...

  3. Contegra conduit for reconstruction of the right ventricular outflow tract: a review of published early and mid-time results

    Directory of Open Access Journals (Sweden)

    Athanasiou Thanos

    2008-11-01

    Full Text Available Abstract Objective The valved conduit Contegra (bovine jugular vein has being implanted for more than 7 years in the right ventricular outflow tract and it is noted that the available reports have been mixed. The aim of this study is to review the reported evidence in the literature. Methods Search of the relevant literature for the primary endpoints of operative mortality and morbidity and secondary endpoints of follow-up haemodynamic performance including severe stenosis, regurgitation and need for reintervention are presented. Results We selected and analysed 17 series including 767 patients. Commonest indication was Fallot's tetralogy. Operative mortality was 2.6%. Operative morbidity was 13.9%. In follow-up, the incidence of intraconduit stenosis was 10.9% (incidence of stenosis for the 12 millimetre conduit was 83.3% in one series and that of at least moderate regurgitation was 6.3%. The aspirin users had a stenosis incidence of 10.5% compared to the non-users had a stenosis incidence of 9.6%. Conclusion A dissent on the performance of the Contegra is discussed, while results are satisfactory in the majority of studies apart for the smallest conduits (12 and 14 millimetre, suggesting an association to compromised run-off. The role of aspirin as antithrombotic modulator remains controversial.

  4. 3-D modeling of ground deformation by conduit pressurization at Soufrière Hills volcano, Montserrat (B.W.I.)

    Science.gov (United States)

    Donnadieu, F.; Voight, B.; Elsworth, D.

    2001-12-01

    Dome growth at the Soufrière Hills volcano between 1996 and 1998 was frequently accompanied by repetitive cycles of earthquakes, ground deformation, degassing, and explosive eruptions. In particular, high-resolution tiltmeters recorded in real-time 6-14 h inflation cycles up to 20 microrad at two stations near the dome. These tilt data were used in eruption forecasting since peak rockfall and pyroclastic flow activity occurred with deflations. The cyclic ground deformation was ascribed to pressurization of the conduit magma beneath the degassing plug. The pressure source has been previously modeled as a point source or finite line source in an elastic medium without considering the topography of the volcano. Using the finite difference code FLAC3D, we modeled the edifice as an elastic medium in three dimensions by integrating surface topography from Montserrat DEMs. We use the available tilt and geodetic data to constrain the geometry and the pressure distribution of the source and the properties of the edifice model. We analyse the effect of the edifice shape as compared to flat free surface models as well as the influence of varied pressure source geometries, pressure distributions, depths and conduit location. Results are compared with previous studies based on analytical models of point or line source and numerical models of conduit pressurization.

  5. Precipitable Water Vapor: Considerations on the water vapor scale height, dry bias of the radiosonde humidity sensors, and spatial and temporal variability of the humidity field

    CERN Document Server

    Otarola, Angel C; Kerber, Florian

    2011-01-01

    The Thirty Meter Telescope (TMT) and the European Extremely Large Telescope (E-ELT) site testing teams have recently finalized their site testing studies. Since atmospheric water vapor is the dominant source of absorption and increased thermal background in the infrared, both projects included precipitable water vapor (PWV) measurements in their corresponding site testing campaigns. TMT planned to monitor PWV at the sites of interest by means of using infrared radiometers. Technical failures and calibration issues prevented them from having a sufficiently long PWV time-series to characterize the sites using this method. Therefore, for the sites in Chile TMT used surface water vapor density measurements, which taken together with an assumed water vapor scale height, allowed for the estimation of PWV. On the other hand, the E-ELT team conducted dedicated PWV measurement campaigns at two of their observatory sites using radiosonde soundings to validate historical time-series of PWV reconstructed by way of a spec...

  6. Vapor bubble generation around gold nano-particles and its application to damaging of cells

    OpenAIRE

    Kitz, M.; Preisser, S.; Wetterwald, A.; Jaeger, M.; Thalmann, G. N.; Frenz, M.

    2011-01-01

    We investigated vapor bubbles generated upon irradiation of gold nanoparticles with nanosecond laser pulses. Bubble formation was studied both with optical and acoustic means on supported single gold nanoparticles and single nanoparticles in suspension. Formation thresholds determined at different wavelengths indicate a bubble formation efficiency increasing with the irradiation wavelength. Vapor bubble generation in Bac-1 cells containing accumulations of the same particles was also investig...

  7. Propose a Correlation to Approximate Nanofluids? Enthalpy of Vaporization - A Numerical Study

    Directory of Open Access Journals (Sweden)

    Mina Mehregan

    2014-02-01

    Full Text Available After studying available experimental data of nanofluids evaporation characteristics, a correlation was proposed by authors to approximate nanofluids’ enthalpy of vaporization. Then the evaporation behavior of nanofuel droplets (fuel droplets containing nanoparticles has been numerically investigated in order to evaluate this relation capability to predict nanofluids evaporation characteristics. Employing the relation in this numerical study led to results in good agreement with experimental data which means capability of this formula to predict nanofluids’ heat of vaporization

  8. Equilibrium solubilities of iodine vapor in water

    International Nuclear Information System (INIS)

    Equilibrium solubilities of iodine vapor in water were measured by introducing iodine vapor, in equilibrium with solid iodine, into water and by circulating it in a closed system, and Henry's law constants were determined. Equilibrium distributions of iodine vapor between a gas phase and an aqueous phase were also measured by another method, and partition coefficients were determined. The solubilities of iodine vapor in water estimated from both the Henry's law constants and the partition coefficients are compared with those of solid iodine reported in the literature. Thermodynamic parameters for the hydration of iodine vapor are evaluated experimentally. (author)

  9. High temperature vapors science and technology

    CERN Document Server

    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

  10. 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

    Science.gov (United States)

    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 setting up BET_EF for Mt Ruapehu we are forced to define quantitatively what the background activity is. This will result in a quantitative evaluation of what changes in long time monitored parameters may influence the probability of future eruptions. The slopes of Mt Ruapehu host the largest ski area in North Island, New Zealand. Lahars have been generated as a result of several eruptions in the last 50 years, and some of these have reached the ski runs in a very short time frame (around 90 seconds from the beginning of the eruption). In the light of these potentially hazardous lahars, we use the output probabilities provided by BET_EF in a practical and rational decision scheme recently proposed by Marzocchi and Woo (2009) based on a cost/benefit analysis (CBA). In such scheme, a C/L ratio is computed, based on the costs (C) of practical mitigation actions to reduce risk (e.g., a public warning scheme and other means of raising awareness, and a call for a temporary and/or partial closure of the ski area) and on the potential loss (L) if no mitigation action is taken and an eruption occurs causing lahars down the ski fields. By comparing the probability of eruption-driven lahars and the C/L ratio, it is possible to define the most rational mitigation actions that can be taken to reduce the risk to skiers, snowboarders and staff on skifield. As BET_EF probability of eruption changes dynamically as updated monitoring data are received, the authorities can decide, at any specific point in time, what is the best action according to the current monitoring of the volcano. In this respect, CBA represents a bridge linking scientific output (probabilities) and Decision Makers (practical mitigation actions).

  11. Active Hydrazine Vapor Sampler (AHVS)

    Science.gov (United States)

    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.

  12. Vapor Growth of III Nitrides

    Science.gov (United States)

    Cai, Dang; Zheng, Lili; Zhang, Hui

    Good understanding of transport phenomena in vapor deposition systems is critical to fast and effective crystal growth system design. Transport phenomena are complicated and are related to operating conditions, such as temperature, velocity, pressure, and species concentration, and geometrical conditions, such as reactor geometry and source-substrate distance. Due to the limited in situ experimental monitoring, design and optimization of growth is mainly performed through semi-empirical and trial-and-error methods. Such an approach is only able to achieve improvement in the deposition sequence and cannot fulfill the increasingly stringent specifications required in industry. Numerical simulation has become a powerful alternative, as it is fast and easy to obtain critical information for the design and optimization of the growth system. The key challenge in vapor deposition modeling lies in developing an accurate simulation model of gas-phase and surface reactions, since very limited kinetic information is available in the literature. In this chapter, GaN thin-film growth by iodine vapor-phase epitaxy (IVPE) is used as an example to present important steps for system design and optimization by the numerical modeling approach. The advanced deposition model will be presented for multicomponent fluid flow, homogeneous gas-phase reaction inside the reactor, heterogeneous surface reaction on the substrate surface, heat transfer, and species transport. Thermodynamic and kinetic analysis will be presented for gas-phase and surface reactions, together with a proposal for the reaction mechanism based on experiments. The prediction of deposition rates is presented. Finally, the surface evolution of film growth from vapor is analyzed for the case in which surface diffusion determines crystal grain size and morphology. Key control parameters for film instability are identified for quality improvement.

  13. Acoustic Droplet Vaporization through PDMS

    Science.gov (United States)

    Li, David; Samuel, Stanley; Fowlkes, J. Brian; Bull, Joseph

    2009-11-01

    Acoustic droplet vaporization (ADV) involves the generation of bubbles from albumin-encapsulated perfluorocarbon (PFC) droplets that have been insonated with high intensity ultrasound (US). Gas embolotherapy, utilizing ADV, may facilitate occlusion of blood flow in the vasculature as bubbles undergo volume expansion of up to 125 times. Cancer therapy could benefit from such occlusions through starvation of the tumor. In order to visualize the detailed mechanics of vaporization and expansion process of the PFC droplets, idealized microvessels were constructed using polydimethylsiloxane (PDMS) channels. Microchannels (20 micron diameter) were fabricated using PDMS with polymer-crosslinker mixing ratios ranging from 5:1 to 20:1. Droplets were introduced into the channels and exposed to US for vaporization. Mixing ratios were observed to impact the impedance matching at the water-PDMS interface, which affected the threshold for ADV. The threshold was lowest for mixing ratios of 5:1 and 20:1, and greatest for 9:1. Final bubble volumes were compared with a computational model by Ye & Bull and were found to be consistent. This work is supported by NIH grant R01EB006476.

  14. Potential N processing by southern Everglades freshwater marshes: Are Everglades marshes passive conduits for nitrogen?

    Science.gov (United States)

    Wozniak, Jeffrey R.; Anderson, William T.; Childers, Daniel L.; Gaiser, Evelyn E.; Madden, Christopher J.; Rudnick, David T.

    2012-01-01

    The degree of hydrological connectivity in wetlands plays a vital role in determining the flux of energy, material, and nutrients across these wet landscapes. During the last century, compartmentalization of hydrologic flows in the Florida Everglades by canals and levees has had a profound impact on the natural timing and supply of freshwater and nutrients across the southern Everglades. Nitrogen (N) is an understudied nutrient in the phosphorus-limited Everglades; it plays an important role in many Everglades processes. To gain a better understanding of the overall N-dynamics in southern Everglades' marshes and the role that canals play in the distribution of N across this landscape, we analyzed ? 15N natural abundance data for the primary ecosystem components (the macrophyte Cladium jamaicense, marl soils, peat soils, and periphyton). Three sample transects were established in the three main basins of the southern Everglades: Shark River Slough, Taylor Slough, and the C-111 basin. Each transect included sample sites near canal inflows, in interior marshes, and at the estuarine ecotone. Natural abundance ? 15N signatures provided insights into processes that may be enriching the 15N content of ecosystem components across the marsh landscape. We also conducted a combined analysis of ? 15N data, tissue N concentrations, and water column N data to provide a broad overview of N cycling in the freshwater marshes of the southern Everglades. The primary trend that emerged from each basin was a significant 15N enrichment of all ecosystem components at near-canal sites, relative to more downstream sample sites. These data suggest that the phosphorus-limited marshes of the southern Everglades are not inactive conduits for N. Rather, these marshes appear to be actively cycling and processing N as it flows from the canal-marsh interface through downstream freshwater marshes. This finding has important implications to downstream coastal estuaries, including Florida Bay, and to nearshore coastal ocean ecosystems, such as coral reefs, where N is the limiting nutrient.

  15. Modeling of the electro-mechanical behavior of ITER Nb3Sn cable in conduit conductors

    Science.gov (United States)

    Breschi, Marco; Ribani, Pier Luigi; Bajas, Hugo; Devred, Arnaud

    2012-05-01

    The coupling of electrical and mechanical modeling of superconducting cable in conduit conductors (CICCs) can be useful for the understanding of the complex phenomena occurring in cables based on strain-sensitive materials like Nb3Sn. The MULTIFIL model is a detailed mechanical model aimed at computing the strain distribution at the strand level in multistrand superconducting cables. MULTIFIL is a finite element code dealing with the contacts between beam assemblies that includes plasticity and it allows modeling both transverse and longitudinal loads applied to the cable. The electromagnetic part of the THELMA code is based on a distributed parameter electrical circuit model of CICCs and is aimed at computing the current distribution and electrical losses at an arbitrary cabling stage. In this work, the maps of strain have been computed with MULTIFIL for a petal of a relevant conductor for the central solenoid of the ITER magnet system. These strain maps were computed in three main cases, namely applying only a thermal compressive strain due to cable contraction in cool-down, considering thermal strain plus the strain due to Lorentz force in a virgin state, and thermal strain plus Lorentz force after a given number of electromagnetic cycles. These strain maps have been implemented in the THELMA code, in order to compute the E-T curves corresponding to the different cases, such deriving important parameters to be compared with experimental results (Tcs, n value, effective strain). A methodology to account in the electrical model for the inhomogeneous strain on the strand cross section due to bending is described and the corresponding results are compared to the case of a homogeneous strain on the wire cross section. The model is able to explain the experimental difference between the physical strain that can be determined with Tc measurements and the effective strain that can be derived from the Tcs measurements.

  16. Speciation and quantification of vapor phases in soy biodiesel and waste cooking oil biodiesel.

    Science.gov (United States)

    Peng, Chiung-Yu; Lan, Cheng-Hang; Dai, Yu-Tung

    2006-12-01

    This study characterizes the compositions of two biodiesel vapors, soy biodiesel and waste cooking oil biodiesel, to provide a comprehensive understanding of biodiesels. Vapor phases were sampled by purging oil vapors through thermal desorption tubes which were then analyzed by the thermal desorption/GC/MS system. The results show that the compounds of biodiesel vapors can be divided into four groups. They include methyl esters (the main biodiesel components), oxygenated chemicals, alkanes and alkenes, and aromatics. The first two chemical groups are only found in biodiesel vapors, not in the diesel vapor emissions. The percentages of mean concentrations for methyl esters, oxygenated chemicals, alkanes and alkenes, and aromatics are 66.1%, 22.8%, 4.8% and 6.4%, respectively for soy biodiesel, and 35.8%, 35.9%, 27.9% and 0.3%, respectively for waste cooking oil biodiesel at a temperature of 25+/-2 degrees C. These results show that biodiesels have fewer chemicals and lower concentrations in vapor phase than petroleum diesel, and the total emission rates are between one-sixteenth and one-sixth of that of diesel emission, corresponding to fuel evaporative emissions of loading losses of between 106 microg l(-1) and 283 microg l(-1). Although diesels generate more vapor phase emissions, biodiesels still generate considerable amount of vapor emissions, particularly the emissions from methyl esters and oxygenated chemicals. These two chemical groups are more reactive than alkanes and aromatics. Therefore, speciation and quantification of biodiesel vapor phases are important. PMID:16904162

  17. Glacier surge mechanism based on linked cavity configuration of the basal water conduit system

    Science.gov (United States)

    Kamb, Barclay

    1987-08-01

    Based on observations of the 1982-1983 surge of Variegated Glacier, Alaska, a model of the surge mechanism is developed in terms of a transition from the normal tunnel configuration of the basal water conduit system to a linked cavity configuration that tends to restrict the flow of water, resulting in increased basal water pressures that cause rapid basal sliding. The linked cavity system consists of basal cavities formed by ice-bedrock separation (cavitation), ˜1 m high and ˜10 m in horizontal dimensions, widely scattered over the glacier bed, and hydraulically linked by narrow connections where separation is minimal (separation gap ? 0.1 m). The narrow connections, called orifices, control the water flow through the conduit system; by throttling the flow through the large cavities, the orifices keep the water flux transmitted by the basal water system at normal levels even though the total cavity cross-sectional area (˜200 m2) is much larger than that of a tunnel system (˜10 m2). A physical model of the linked cavity system is formulated in terms of the dimensions of the "typical" cavity and orifice and the numbers of these across the glacier width. The model concentrates on the detailed configuration of the typical orifice and its response to basal water pressure and basal sliding, which determines the water flux carried by the system under given conditions. Configurations are worked out for two idealized orifice types, step orifices that form in the lee of downglacier-facing bedrock steps, and wave orifices that form on the lee slopes of quasisinusoidal bedrock waves and are similar to transverse "N channels." The orifice configurations are obtained from the results of solutions of the basal-sliding-with-separation problem for an ice mass constituting of linear half-space of linear rheology, with nonlinearity introduced by making the viscosity stress-dependent on an intuitive basis. Modification of the orifice shapes by melting of the ice roof due to viscous heat dissipation in the flow of water through the orifices is treated in detail under the assumption of local heat transfer, which guarantees that the heating effects are not underestimated. This treatment brings to light a melting-stability parameter ? that provides a measure of the influence of viscous heating on orifice cavitation, similar but distinct for step and wave orifices. Orifice shapes and the amounts of roof meltback are determined by ?. When ? ? 1, so that the system is "viscous-heating-dominated," the orifices are unstable against rapid growth in response to a modest increase in water pressure or in orifice size over their steady state values. This growth instability is somewhat similar to the jökulhlaup-type instability of tunnels, which are likewise heating-dominated. When ? ? 1, the orifices are stable against perturbations of modest to even large size. Stabilization is promoted by high sliding velocity ?, expressed in terms of a ?-½ and ?-1 dependence of ? for step and wave cavities. The relationships between basal water pressure and water flux transmitted by linked cavity models of step and wave orifice type are calculated for an empirical relation between water pressure and sliding velocity and for a particular, reasonable choice of system parameters. In all cases the flux is an increasing function of the water pressure, in contrast to the inverse flux-versus-pressure relation for tunnels. In consequence, a linked cavity system can exist stably as a system of many interconnected conduits distributed across the glacier bed, in contrast to a tunnel system, which must condense to one or at most a few main tunnels. The linked cavity model gives basal water pressures much higher than the tunnel model at water fluxes ?1 m3/s if the bed roughness features that generate the orifices have step heights or wave amplitudes less than about 0.1 m. The calculated basal water pressure of the particular linked cavity models evaluated is about 2 to 5 bars below ice overburden pressure for water fluxes in the

  18. Observation system simulation experiments using water vapor isotope information

    Science.gov (United States)

    Yoshimura, Kei; Miyoshi, Takemasa; Kanamitsu, Masao

    2014-07-01

    Measurements of water vapor isotopes (?18O and ?D) have dramatically increased in recent years with the availability of new spectroscopic technology. To utilize these data more efficiently, this study first developed a new data assimilation system using a local transform ensemble Kalman filter (LETKF) and the Isotope-incorporated Global Spectral Model (IsoGSM). An observation system simulation experiment (OSSE) was then conducted. The OSSE used a synthetic data set of vapor isotope measurements, mimicking Tropospheric Emission Spectrometer (TES)-retrieved ?D from the mid-troposphere, SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY)-retrieved ?D from the water vapor column, and the virtual Global Network of Isotopes in Precipitation (GNIP)-like surface vapor isotope (both ?D and ?18O) monitoring network. For TES and SCIAMACHY, we assumed a similar spatiotemporal coverage as that of the real data sets. For the virtual GNIP-like network, we assumed ~200 sites worldwide and 6-hourly measurements. An OSSE with 20 ensemble members was then conducted for January 2006. The results showed a significant improvement in not only the vapor isotopic field but also meteorological fields, such as wind speed, temperature, surface pressure, and humidity, when compared with a test with no observations. For surface air temperature, the global root mean square error has dropped by 10%, with 40-60% of the decrease occurring in the east-southeast Asia where the concentration of observations is relatively higher. When there is a conventional radiosonde network, the improvement gained by adding isotopic measurements was small but positive for all variables.

  19. Análise do tratamento cirúrgico da raiz da aorta com o tubo valvulado e com a preservação da valva aórtica Analysis of aortic root surgery with composite mechanical aortic valve conduit and valve-sparing reconstruction

    Directory of Open Access Journals (Sweden)

    Ricardo Ribeiro Dias

    2010-12-01

    Full Text Available OBJETIVO: Análise comparativa dos resultados imediatos e tardios da reconstrução da raiz da aorta com o tubo valvulado e com a preservação da valva aórtica. MÉTODOS: No período de novembro de 2002 a setembro de 2009, 164 pacientes com idade média de 54 ± 15 anos, sendo 115 do sexo masculino, foram submetidos ao tratamento cirúrgico da raiz da aorta. Foram 125 tubos valvulados e 39 reconstruções da raiz da aorta com preservação da valva aórtica. Dezesseis por cento dos pacientes eram portadores de síndrome de Marfan e 4,3% apresentavam valva aórtica bivalvulada. Cento e quarenta e quatro (88% pacientes foram acompanhados durante tempo médio de seguimento de 41,1 ± 20,8 meses. RESULTADOS: A mortalidade hospitalar total foi de 4,9%; sendo 5,6% nas operações com tubo valvulado e 2,6% nas preservações da valva aórtica (POBJECTIVE: Comparative analysis of early and late results of aortic root reconstruction with aortic valve sparing operations and the composite mechanical valve conduit replacement. METHODS: From November 2002 to September 2009, 164 consecutive patients with mean age 54 ± 15 years, 115 male, underwent the aortic root reconstruction (125 mechanical valve conduit replacements and 39 valve sparing operations. Sixteen percent of patients had Marfan syndrome and 4.3% had bicuspid aortic valve. One hundred and forty-four patients (88% were followed for a mean period of 41.1 ± 20.8 months. RESULTS: The hospital mortality was 4.9%, 5.6% in operations with valved conduits and 2.6% in the valve sparing procedures (P <0.05. There was no difference neither in survival (95% CI = 86% - 96%, P= 0.1 nor in reoperation-free survival (95% CI = 85% - 90%, P = 0.29. The survival free of complications such as bleeding, thromboembolism and endocarditis were favorable to the valve sparing operations, respectively (95% CI = 70% - 95%, P = 0.001, (95% CI = 82% - 95% P = 0.03 and (95% CI = 81% - 95%, P = 0.03. Multivariate analysis showed that creatinine greater than 1.4 mg/dl, Cabrol operation and renal dialysis were predictors of mortality, respectively, with occurrence chance of 6 (95% CI = 1.8 - 19.5, P = 0.003, 12 (95% CI = 3 - 49.7, P = 0.0004 and 16 (95% CI = 3.6 - 71.3, P = 0.0002. CONCLUSIONS: The aortic root reconstruction has a low early and late mortality, high survival free of complications and low need for reoperation. During the late follow-up, valve sparing aortic root reconstructions presented fewer incidences of bleeding, thromboembolic events and endocarditis.

  20. Control of flow through a vapor generator

    Science.gov (United States)

    Radcliff, Thomas D.

    2005-11-08

    In a Rankine cycle system wherein a vapor generator receives heat from exhaust gases, provision is made to avoid overheating of the refrigerant during ORC system shut down while at the same time preventing condensation of those gases within the vapor generator when its temperature drops below a threshold temperature by diverting the flow of hot gases to ambient and to thereby draw ambient air through the vapor generator in the process. In one embodiment, a bistable ejector is adjustable between one position, in which the hot gases flow through the vapor generator, to another position wherein the gases are diverted away from the vapor generator. Another embodiment provides for a fixed valve ejector with a bias towards discharging to ambient, but with a fan on the downstream side of said vapor generator for overcoming this bias.

  1. Cirurgia coronária com condutos arteriais múltiplos sem circulação extracorpórea Off-pump coronary artery bypass with multiple arterial conduits

    Directory of Open Access Journals (Sweden)

    Daniel Navia

    2005-03-01

    Full Text Available OBJETIVO: Analisar os resultados, em 30 dias, em pacientes submetidos de forma eletiva à revascularização arterial total do miocárdio sem circulação extracorpórea (CEC, e identificar preditores de morbimortalidade com esta estratégia cirúrgica. MÉTODO: Entre maio de 1999 e fevereiro de 2004, efetuaram-se 203 cirurgias de revascularização miocárdica (CRM com revascularização arterial total sem CEC, em pacientes com doença de múltiplos vasos (três vasos 81,7%, doença de um vaso excluída. Reportaram-se variáveis pré-operatórias e comorbidade: média de idade 63,9 ± 9,13 anos, homens 182 (89,5%, hipertensão 132 (65%, tabagismo 125 (61%, hipercolesterolemia 152 (74,8%, infarto agudo do miocárdio prévio (mais de 30 dias 73 (35%, disfunção ventricular moderada a grave 31 (15%, reoperação cinco (2,5%. A revascularização arterial total incluiu anastomoses em T e seqüenciais com artéria torácica interna esquerda (100%, torácica interna direita (56,6% e artéria radial (63%. O número total de anastomoses foi 576 (média de três pontes/paciente, todas efetuadas com estabilizadores mecânicos externos. Não form realizadas anastomoses proximais na aorta. Cirurgia com CEC foi realizada em três (1,5% pacientes. Noventa por cento dos pacientes foram extubados na sala de operações. Para a análise estatística, utilizou-se teste de regressão logística múltipla. RESULTADOS: A incidência de fibrilação atrial pós-operatória foi de 12,8% (26, insuficiência renal oligoanúrica 3% (seis, diálise 0,49% (um, infarto de miocárdio pós-operatório 1,47% (três, baixo débito cardíaco 4% (oito, reoperação por sangramento 1,47% (três, mediastinite 1,47% (três, acidente vascular cerebral 1,47% (três. A mortalidade intra-hospitalar foi de 2,45% (cinco. O único preditor independente de morbidade em 30 dias foi a idade (p=0,033; OR 1,04; IC 95%: 1-1,08. CONCLUSÃO: A cirurgia de revascularização miocárdica sem circulação extracorpórea utilizando condutos arteriais para a doença de múltiplos vasos é factível com baixa morbimortalidade em 30 dias.OBJECTIVE: To analyze intra-hospital results in patients undergoing elective off-pump total arterial revascularization and identify morbidity and mortality predictors using this surgical strategy. METHOD: From May 1999 to February 2004, 203 myocardial revascularization procedures with total arterial revascularization without cardiopulmonary bypass (off-pump were carried out in patients with multivessel disease (three vessels 81.7 %, one vessel disease was excluded. We report pre-surgical variables and co-morbidities: average age 63.9 ± 9.13 years, men 182 (89.5%, hypertension 132 (65%, smokers 125 (61%, hypercholesterolemia 152 (74.8%, previous myocardial infarction (> 30 days 73 (35%, moderate to severe ventricular dysfunction 31 (15%, redo five (2.5%. Total arterial revascularization included T-grafts and sequential grafts with left internal mammary (100%, right internal mammary (56.6% and radial (63% arteries. The total number of distal anastomosis was 576 (mean of three grafts/patient, all carried out with external mechanical stabilizers. There were no proximal aortic anastomoses. Conversion to on-pump surgery occurred in three (1.5% patients; 90% of the patients was extubated in the operating room. The multiple logistic regression test was used for statistical analysis. RESULTS: The postoperative incidence of atrial fibrillation was 12.8% (26, oligoanuric renal failure 3% (six, dialysis 0.49% (one, postoperative myocardial infarction 1.47% (three, low cardiac output 4% (eight, Redo for bleeding 1.47% (three, mediastinitis 1.47% (three, stroke 1.47% (three. Intra-hospital mortality was 2.45% (five. The only independent 30 day morbidity predictor was age (p=0.033; OR 1.04; IC 95%: 1-1.08. CONCLUSION: Off-pump myocardial revascularization with arterial conduits for multiple vessel disease is feasible with a low 30-day morbidity and mortality.

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

    Science.gov (United States)

    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.

  3. Water vapor and the dynamics of climate changes

    CERN Document Server

    Schneider, Tapio; Levine, Xavier

    2009-01-01

    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 non-monotonically 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 circul...

  4. An interim reference model for the variability of the middle atmosphere H2O vapor distribution

    Science.gov (United States)

    Remsberg, E. E.; Russell, J. M., III; Wu, C. Y.

    1989-01-01

    Water vapor is an important minor constituent in the studies of the middle atmosphere for a variety of reasons, including its role as a source for active HO(y) chemicals and its use in analysis of transport processes. A number of in situ and remote techniques were employed in the determination of water vapor distributions. Two of the more complete data sets were used to develop an interim reference profile. First, there are the seven months of Nimbus 7 limb infrared monitor of the stratosphere (LIMS) data obtained during Nov. 1978 to May 1979 over the range 64S to 84N latitude and from about 100 to 1 mb in the mid-mesosphere at several fixed Northern Hemisphere mid-latitude sites. These two data sets were combined to give a mid-lattitude, interim reference water vapor profile for the entire vertical range of the middle atmosphere and with accuracies of better than 25 percent. The daily variability of stratospheric water vapor profiles about the monthly mean was also established from these data sets for selected months. Information is also provided on the longitudinal variability of LIMS water vapor profiles about the daily, weekly, and monthly zonal means. Generally, the interim reference water vapor profile and its variability are consistent with prevailing ideas about chemistry and transport.

  5. Destilación de aceite usando vapor con propano

    OpenAIRE

    Edrez-garnica, M. A. Ram U.; Cazarez-candia, O.; Mamora, D. D.

    2007-01-01

    Con el fin de mejorar la producción de aceites pesados, en trabajos previos se han realizado experimentos relacionados con la inyección de vapor y el uso de propano como aditivo, obteniéndose los siguientes resultados: (1) se acelera la producción, (2) se incrementa la inyectividad del vapor, y (3) la velocidad del frente de vapor es más grande. Estos resultados indican un mejoramiento de las propiedades del aceite, sin embargo, con dichos experimentos no es posible explicar ...

  6. Chemical vapor deposited zinc sulfide

    CERN Document Server

    McCloy, John S

    2013-01-01

    Zinc sulfide has shown unequaled utility for infrared windows that require a combination of long-wavelength infrared transparency, mechanical durability, and elevated-temperature performance. This book reviews the physical properties of chemical vapor deposited ZnS and their relationship to the CVD process that produced them. An in-depth look at the material microstructure is included, along with a discussion of the material's optical properties. Finally, because the CVD process itself is central to the development of this material, a brief history is presented.

  7. Pulsed copper halide vapor lasers

    Science.gov (United States)

    Kazarian, M. A.; Petrash, G. G.; Trofimov, A. N.

    The theory and the performance characteristics of copper halide lasers are examined with reference to recent theoretical and experimental research in the field of metal vapor lasers. The discussion covers gas discharge tubes, comparative characteristics of copper halide lasers, determination of the metastable level decomposition rates in copper chloride and copper bromide lasers, and spectroscopic measurements of the discharge plasma in copper halide lasers. Attention is also given to the kinetics of copper atoms formation in copper halide lasers and calculation of the kinetic characteristics of copper halide lasers.

  8. Dual frequency water vapor radiometer

    Science.gov (United States)

    Xu, Peiyuan; Jin, Peiyu; Yao, Zhunliang; Fang, Zhenhe; Li, Mingxiang

    A steerable dual frequency water vapor radiometer (DFWVR) is developed. A pair of optimum frequencies, 20.60 and 31.65 GHz, is adopted. Each frequency channel has its own offset parabola antenna and Dicke switched receiver, but both channels are mounted on one rotatable pedestal and controlled by one microcomputer system. This DFWVR is capable of continuous, unattended operation. The sensitivity at 1 second time constant and the accuracy of the brightness temperature are 0.2 and 0.5 K, respectively, at both frequencies. It is expected to promote the excess path length corrections to be better than 1 cm for geodetic VLBI and GPS measurements.

  9. Advanced Raman water vapor lidar

    Science.gov (United States)

    Whiteman, David N.; Melfi, S. Harvey; Ferrare, Richard A.; Evans, Keith A.; Ramos-Izquierdo, Luis; Staley, O. Glenn; Disilvestre, Raymond W.; Gorin, Inna; Kirks, Kenneth R.; Mamakos, William A.

    1992-01-01

    Water vapor and aerosols are important atmospheric constituents. Knowledge of the structure of water vapor is important in understanding convective development, atmospheric stability, the interaction of the atmosphere with the surface, and energy feedback mechanisms and how they relate to global warming calculations. The Raman Lidar group at the NASA Goddard Space Flight Center (GSFC) developed an advanced Raman Lidar for use in measuring water vapor and aerosols in the earth's atmosphere. Drawing on the experience gained through the development and use of our previous Nd:YAG based system, we have developed a completely new lidar system which uses a XeF excimer laser and a large scanning mirror. The additional power of the excimer and the considerably improved optical throughput of the system have resulted in approximately a factor of 25 improvement in system performance for nighttime measurements. Every component of the current system has new design concepts incorporated. The lidar system consists of two mobile trailers; the first (13m x 2.4m) houses the lidar instrument, the other (9.75m x 2.4m) is for system control, realtime data display, and analysis. The laser transmitter is a Lambda Physik LPX 240 iCC operating at 400 Hz with a XeF gas mixture (351 nm). The telescope is a .75m horizontally mounted Dall-Kirkham system which is bore sited with a .8m x 1.1m elliptical flat which has a full 180 degree scan capability - horizon to horizon within a plane perpendicular to the long axis of the trailer. The telescope and scan mirror assembly are mounted on a 3.65m x .9m optical table which deploys out the rear of the trailer through the use of a motor driven slide rail system. The Raman returns from water vapor (403 nm), nitrogen (383 nm) and oxygen (372 nm) are measured in addition to the direct Rayleigh/Mie backscatter (351). The signal from each of these is split at about a 5/95 ratio between two photomultiplier detectors. The 5 percent detector is used for measurements below about 4.0 km, while the 95 percent detector provides the information above this level.

  10. Structural controls on karstic conduits in a collisional orogen (Sierra de las Nieves, Betic Cordillera, S Spain)

    Science.gov (United States)

    Pedrera, A.; Luque-Espinar, J. A.; Martos-Rosillo, S.; Pardo-Igúzquiza, E.; Durán-Valsero, J. J.; Martínez-Moreno, F.; Guardiola-Albert, C.

    2015-06-01

    We characterize the fracture pattern, including both meso-scale joints and macro-scale faults, within the central sector of Sierra de las Nieves (Betic Cordillera, S Spain), which contains one of the largest karstification systems in Europe. Structural data were compared with the direction pattern of the karstic conduit network of the largest caves. Carbonate rocks were deformed in a collisional setting and exposed at the surface since the early Miocene. Normal and normal-oblique faults trending NW-SE to WNW-ESE are the most prominent brittle structures, having formed coevally with shorter NE-SW normal to normal-dextral after the main thrusting phase. In addition, two main open joint sets striking NW-SE and NE-SW developed on a broad scale. Orthogonal normal faults and open joints suggest an extensional setting characterized by horizontal minimum (S3) and intermediate (S2) stress axes of similar magnitudes that intermittently shifted their positions during the middle-to-late Miocene. Vertical water flow coming from direct recharge sectors tends to infiltrate across these high-dipping faults, mainly concentrating at fault intersections, thus favoring sub-vertical conduit formation within the vadose zone. Horizontal paleo-phreatic levels are perched linked to the recent uplift undergone by the sector, giving us the opportunity to analyze the incidence of fractures at the phreatic zone. Joint sets determine the hydraulic anisotropy within the former phreatic levels. Because our study illustrates the primary role of diverse tectonic structures during massive multiphase cave development above and below the water table, it could contribute to better constraining of the models of karstic conduit formation.

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

    Science.gov (United States)

    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.

  12. Gravity sensitivity of a resistojet water vaporizer

    Science.gov (United States)

    Morren, W. Earl

    1993-01-01

    A laboratory model of a water vaporizer for resistojet applications was designed, fabricated, and steady and transient characteristics were measured. Vaporizer operation was not impacted by rotation about a horizontal axis normal to its own. The vaporizer was operated under low and high accelerations aboard a jet aircraft for periods up to 25 s at flow rates ranging from 159(10)(exp -6) to 230(10)(exp -6) kg/s. Slight changes in inlet and outlet pressures and some heat exchanger temperatures were observed during the low-gravity tests. However, the results of these tests indicated probable compatibility of the vaporizer design tested with a low-gravity environment.

  13. Global monitoring of tropospheric water vapor with GPS radio occultation aboard CHAMP

    CERN Document Server

    Heise, S; Beyerle, G; Schmidt, T; Reigber, C

    2005-01-01

    The paper deals with application of GPS radio occultation (RO) measurements aboard CHAMP for the retrieval of tropospheric water vapor profiles. The GPS RO technique provides a powerful tool for atmospheric sounding which requires no calibration, is not affected by clouds, aerosols or precipitation, and provides an almost uniform global coverage. We briefly overview data processing and retrieval of vertical refractivity, temperature and water vapor profiles from GPS RO observations. CHAMP RO data are available since 2001 with up to 200 high resolution atmospheric profiles per day. Global validation of CHAMP water vapor profiles with radiosonde data reveals a bias of about 0.2 g/kg and a standard deviation of less than 1 g/kg specific humidity in the lower troposphere. We demonstrate potentials of CHAMP RO retrievals for monitoring the mean tropospheric water vapor distribution on a global scale.

  14. Platform-to-platform sample transfer, distribution, dilution, and dosing via electrothermal vaporization and electrostatic deposition

    CERN Document Server

    Hermann, G; Matz, R; Gafurov, M; Gilmutdinov, A; Nagulin, K; Frech, W; Bjoern, E; Grinshtein, I; Vasilieva, L

    2004-01-01

    A novel system for solid sample pretreatment, handling, and dosing for analytical atomic spectrometry is described. A primary solid or liquid sample is vaporized in a graphite furnace and then condensed in a specially designed condensation zone. On the further transport path, the analyte aerosol can be diluted and distributed in pre-set ratios. Applying a corona discharge, aerosol particulates are then quantitatively re-collected by means of intra-furnace electrostatic precipitation on the platform of another graphite furnace or by external precipitation on one or a set of platforms. Furthermore, the described procedure allows external thermal sample pretreatment with preceding pyrolysis and additional vaporization, condensation, and re-precipitation that significantly reduces or removes the sample matrix. Owing to different losses, transport efficiencies of electrothermal vaporization (ETV) instrumentation depend on analyte element, matrix, vaporization temperature, ramp rate, and tube history. In order to r...

  15. Use of a Peripherally Inserted Central Catheter as a Conduit for Central Venous Access Across Thrombosed Great Veins

    International Nuclear Information System (INIS)

    This report describes a technique of inserting an implantable venous access port (portacath) through a thrombosed and occluded vein employing a pre-existing peripherally inserted central catheter (PICC) as the route of access. The PICC was used as a conduit for venous access in a way that has not been described previously in the literature. This procedure was performed in a young patient with cystic fibrosis in an effort to prevent the use of his virgin contralateral veins, which might be used in the future.

  16. Dummy coil development for the cable-in-conduit Nb3Sn ''outsert'' coils of the 45T hybrid magnet

    International Nuclear Information System (INIS)

    Intermagnetics General Corporation, under a Phase 1 contract with the National High Magnetic Field Laboratory at Florida State University, is developing and demonstrating the manufacturing technology for the cable-in-conduit conductor (CICC) for the Nb3Sn ''outsert'' coils of the 45T hybrid magnet. This paper presents the technical development of cabling and sheathing of long length dummy CICC and the progress of manufacturing development for the full-diameter coil ''A'' using the dummy CICC. This will include coil stress analyses, winding technique, Helium penetration ports, terminations, CIC conductor insulation, heat treatment and epoxy impregnation

  17. Redo-redo aortic root replacement with a mechanical valved conduit in a patient with von Willebrand's disease: Case report

    Directory of Open Access Journals (Sweden)

    Shaikhrezai Kasra

    2010-08-01

    Full Text Available Abstract A 40 year-old female, with a history of cardiac surgery for congenital aortic valve stenosis and von Willebrand's disease (VWD presented with increasing shortness of breath due to mixed aortic valve dysfunction. With a paucity of such cases in the literature, we describe the successful outcome of a patient with VWD who underwent elective redo-redo aortic root replacement with a mechanical valved conduit. She was given a three-month trial of warfarin pre-operatively to evaluate the extent of bleeding risk. Her post-operative course was uneventful and she was discharged home after six days.

  18. Connecting conduit-free and bypass circuit-less mini LVADs eliminate the most likely sites of thrombosis

    OpenAIRE

    Kun-Xi Qian

    2009-01-01

    All existing left ventricular assist devices (LVADs) need inlet and outlet connecting con-duits and the assist pumping blood flows through the bypass circuit from left ventricle to aorta. It will result in some most likely sites of thrombosis and brings about physiological dis-turbance to natural circulation, as well as addi-tional need for anatomic occupation in chest. The author developed a trans-apical and cross-valvular intra-ventricular axial pump and an aortic valvo- pump to solve these...

  19. The stochastic quantization method and its application to the numerical simulation of volcanic conduit dynamics under random conditions

    Directory of Open Access Journals (Sweden)

    E. Peruzzo

    2010-06-01

    Full Text Available Stochastic Quantization (SQ is a method for the approximation of a continuous probability distribution with a discrete one. The proposal made in this paper is to apply this technique to reduce the number of numerical simulations for systems with uncertain inputs, when estimates of the output distribution are needed. This question is relevant in volcanology, where realistic simulations are very expensive and uncertainty is always present. We show the results of a benchmark test based on a one-dimensional steady model of magma flow in a volcanic conduit.

  20. The stochastic quantization method and its application to the numerical simulation of volcanic conduit dynamics under random conditions

    Directory of Open Access Journals (Sweden)

    E. Peruzzo

    2010-03-01

    Full Text Available Stochastic Quantization (SQ is a method for the approximation of a continuous probability distribution with a discrete one. The proposal made in this paper is to apply this technique to reduce the number of numerical simulations for systems with uncertain inputs, when estimates of the output distribution are needed. This question is relevant in volcanology, where realistic simulations are very expensive and uncertainty is always present. We show the results of a benchmark test based on a one-dimensional steady model of magma flow in a volcanic conduit.

  1. Écoulement gaz-liquide transitoire en conduite horizontale Transient Gas-Liquid Flow in a Horizontal Pipe

    Directory of Open Access Journals (Sweden)

    Caussade B.

    2006-11-01

    Full Text Available Les phénomènes instationnaires en écoulements diphasiques se rencontrent dans beaucoup de situations pratiques et notamment en génie pétrolier pour le transport en conduite de mélanges de gaz et d'huile, et en génie nucléaire pour les problèmes liés à la sécurité des réacteurs. Jusqu'à aujourd'hui, la plupart des travaux à caractère théorique et expérimental ont porté sur l'étude des écoulements à phases séparées et à bulles. L'étude que nous présentons est principalement axée sur les phénomènes transitoires à basse fréquence que l'on rencontre dans les écoulements à poches et bouchons lorsque les conditions à l'entrée de la conduite varient. L'étude expérimentale a été menée dans une conduite de 90 m de long et de 5,3 cm de diamètre intérieur, alimentée avec de l'eau et de l'air dont les débits, de l'une ou l'autre phase, peuvent être soumis à des variations brusques. Une instrumentation appropriée permet d'accéder à la connaissance de la valeur instantanée du taux de gaz et de la pression, en 5 sections de mesure disposées le long de la conduite, ainsi que du débit liquide en sortie. Pour dégager les traits caractéristiques du régime transitoire, une moyenne d'ensemble sur un grand nombre d'échelons de débit (entre 100 et 200 s'est avérée nécessaire et particulièrement bien adaptée. La présentation des résultats de quelques essais types et les commentaires qu'ils suggèrent terminent l'exposé. Unsteady phenomena in two-phase flows occur in many practical situations related in particular to the transport of oil-gas mixtures in pipes and to the safety of nuclear reactors. Until now most research has been devoted to the study of separate-phase and bubbly flows from both the theoretical and experimental points of view. This study mainly focuses on the unsteady large-scale phenomena occurring in horizontal slug flows when the inlet conditions are changed. An experimental investigation was performed, in a 5. 3-cm ID pipe 90 m long, with air-water flows subjected to sudden variations in gas or liquid flow rates. The instantaneous values of the void fractions and the pressures in five test sections were obtained together with the liquid flow rate at the outlet. To characterize the transient-flow response, ensemble averages taken over more than 100 steps of flow rates were calculated for each run. Typical results are presented and discussed from the physical point of view.

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

    OpenAIRE

    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 moistur...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Thomas, J. Christopher; Trend, John E.; Rakow, Neal A.; Wendland, Michael S.; Poirier, Richard J.; Paolucci, Dora M.

    2011-01-01

    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. PMID:22163798

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

    Directory of Open Access Journals (Sweden)

    TetsujiYamaoka

    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.

  6. Mechanical tests of the conduit tubes of a conductor for the Toroidal winding of the International Thermonuclear Experimental Reactor (ITER)

    Science.gov (United States)

    Krivykh, A. V.; Anashkin, O. P.; Keilin, V. E.; Diev, D. N.; Dinisilov, A. S.; Shcherbakov, V. I.; Tronza, V. I.

    2012-11-01

    Extremely stringent requirements, which include the impact toughness at the liquid-helium temperature, are imposed on the material of the conduit tubes for International Thermonuclear Experimental Reactor (ITER) Toroidal Field (TF) conductors. Modified 316LN-IG stainless steel is recommended as the conduit tube material. Steel 316LN-IG tube samples (both full-size samples and sub-sized samples) are subjected to mechanical tests at various stages of the process of conductor production: in the as-recieved state and after compacting, preliminary elongation by 2.5% at room temperature, and annealing at 650°C for 200 h in a pure helium gas atmosphere. The tests are carried out at room, liquid nitrogen, and liquid helium temperatures and satisfy the standards of the American Society of Mechanical Engineers (ASME and ASTM). The results of sub-size and full-size samples testing show that the last one gives more representative results to qualify the weld joints in liquid nitrogen. When the temperature decreases or the strain increases, the magnetization of the samples increases, especially in the weld area. Strain measurements with an extensometer demonstrate that the intracrystal processes occurring at the liquid-helium temperature can lead to a significant change in the local load, up to complete unloading in a deformation zone. Unusual local serrated deformation is observed with an extensometer installed in the weld area during tests in liquid helium: this deformation is the result of compressive jumps opposite to the loading direction.

  7. Transient Simulation of Two-Phase Flows in Pipes Simulation transitoire des écoulements diphasiques dans les conduites

    Directory of Open Access Journals (Sweden)

    Tran Q. H.

    2006-12-01

    Full Text Available Transient simulation of two-phase gas-liquid flow in pipes requires considerable computational efforts. Until recently, most available commercial codes are based on two-fluid models which include one momentum conservation equation for each phase. However, in normal pipe flow, especially in oil and gas transport, the transient response of the system proves to be relatively slow. Thus, it is reasonable to think that simpler forms of the transport equations might suffice to represent transient phenomena. Furthermore, these types of models may be solved using less time-consuming numerical algorithms. La simulation transitoire des écoulements diphasiques gaz-liquide dans les conduites requiert des efforts de calcul considérables. Jusqu'à récemment, la plupart des codes de simulation commercialement disponibles étaient basés sur des modèles à deux fluides mettant en Suvre une équation de conservation de la quantité de mouvement pour chaque phase. Toutefois, dans les processus normaux de transport pétrolier dans les conduites, et spécialement de transport de pétrole ou de gaz, la réponse transitoire du système se révèle être relativement lente. Ainsi, il est raisonnable de penser qu'une forme simplifiée des équations de transport pourrait être suffisante pour reproduire de tels phénomènes transitoires. De plus, ce type de modèle pourrait être résolu numériquement au moyen d'algorithmes moins coûteux en temps calcul.

  8. LNG fire and vapor control system technologies

    Energy Technology Data Exchange (ETDEWEB)

    Konzek, G.J.; Yasutake, K.M.; Franklin, A.L.

    1982-06-01

    This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and vapor control systems. In this report a brief summary of LNG physical properties is given. This is followed by a discussion of basic fire and vapor control design philosophy and detailed reviews of fire and vapor control practices. The operating characteristics and typical applications and application limitations of leak detectors, fire detectors, dikes, coatings, closed circuit television, communication systems, dry chemicals, water, high expansion foam, carbon dioxide and halogenated hydrocarbons are described. Summary descriptions of a representative LNG peakshaving facility and import terminal are included in this report together with typical fire and vapor control systems and their locations in these types of facilities. This state-of-the-art review identifies large differences in the application of fire and vapor control systems throughout the LNG industry.

  9. Risk assessment of metal vapor arcing

    Science.gov (United States)

    Hill, Monika C. (Inventor); Leidecker, Henning W. (Inventor)

    2009-01-01

    A method for assessing metal vapor arcing risk for a component is provided. The method comprises acquiring a current variable value associated with an operation of the component; comparing the current variable value with a threshold value for the variable; evaluating compared variable data to determine the metal vapor arcing risk in the component; and generating a risk assessment status for the component.

  10. Vapor Wall Deposition in Chambers: Theoretical Considerations

    Science.gov (United States)

    McVay, R.; Cappa, C. D.; Seinfeld, J.

    2014-12-01

    In order to constrain the effects of vapor wall deposition on measured secondary organic aerosol (SOA) yields in laboratory chambers, Zhang et al. (2014) varied the seed aerosol surface area in toluene oxidation and observed a clear increase in the SOA yield with increasing seed surface area. Using a coupled vapor-particle dynamics model, we examine the extent to which this increase is the result of vapor wall deposition versus kinetic limitations arising from imperfect accommodation of organic species into the particle phase. We show that a seed surface area dependence of the SOA yield is present only when condensation of vapors onto particles is kinetically limited. The existence of kinetic limitation can be predicted by comparing the characteristic timescales of gas-phase reaction, vapor wall deposition, and gas-particle equilibration. The gas-particle equilibration timescale depends on the gas-particle accommodation coefficient ?p. Regardless of the extent of kinetic limitation, vapor wall deposition depresses the SOA yield from that in its absence since vapor molecules that might otherwise condense on particles deposit on the walls. To accurately extrapolate chamber-derived yields to atmospheric conditions, both vapor wall deposition and kinetic limitations must be taken into account.

  11. 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.

    Science.gov (United States)

    Xue, Feng; Wu, Er-Jun; Zhang, Pei-Xun; Li-Ya, A; Kou, Yu-Hui; Yin, Xiao-Feng; Han, Na

    2015-01-01

    We examined the restorative effect of modified 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 transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial fibrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury. PMID:25788929

  12. 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

    Directory of Open Access Journals (Sweden)

    Feng Xue

    2015-01-01

    Full Text Available We examined the restorative effect of modified 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 transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker and glial fibrillary acidic protein (glial cell marker at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

  13. Influence of mass flow rate on Turbulent Kinetic Energy (TKE) distribution in Cable-in-Conduit Conductors (CICCs) used for fusion grade magnets

    International Nuclear Information System (INIS)

    Highlights: • Mechanism associated with turbulent flow in CICC is investigated using CFD. • Reynolds Number (Re) affects the TKE in central channel but not that in bundle channel. • The loss of TKE occurs at the interface between central and bundle channels. • The loss of TKE is also observed as the flow progresses past the spiral rib. • In the absence of external heat sources, loss of TKE leads to temperature rise of SHe. -- Abstract: Thermohydraulic analysis is beneficial to understand the complex flow behavior in dual channel cable-in-conduit conductors (CICC) used in Tokomaks such as International Thermonuclear Experimental Reactor (ITER). Such dual channel CICC contains an annular and a central channel separated by a spiral. The cable bundle channel of CICC can be assumed to be porous and the central channel a clear region for thermohydraulic analysis using Computational Fluid Dynamics (CFD). Flow through CICC is found to be turbulent and this turbulence is transported in the form of small eddies. These eddies may dissipate the energy in the form of heat while being transported and finally the smaller eddies may combine to form larger eddy or may die out. Such phenomenon can be well explained with the help of a parameter called Turbulent Kinetic Energy (TKE), which determines the energy possessed by the eddies in the turbulent flow. In the present work, a three dimensional model of dual channel CICC is developed in GAMBIT-2.1 and solved using a compatible solver FLUENT-6.3.26. The influence of mass flow rate on Turbulent Kinetic Energy (TKE), which is defined as the mean kinetic energy per unit mass associated with eddies in turbulent flow, is analyzed. The computational results of pressure drop and flow repartition are validated against relevant experimental published results

  14. Electrothermal vaporization, part 2: surface chemistry

    Science.gov (United States)

    Majidi, Vahid; Smith, Robert G.; Xu, Ning; McMahon, Melissa W.; Bossio, Robert

    2000-12-01

    This review is the second of a two-part series on evaluation of vaporization and atomization processes in electrothermal vaporizers (ETV), focused specifically on surface chemistry in ETVs. Laser desorption mass spectrometry and differential scanning calorimetry are used to investigate vaporization of Mg, Ca, Sr, Ba, and Ni. Graphite, Al, and Ta were used as the vaporizer substrate material to elucidate potential pathways with regard to surface chemistry. The results presented in parts 1 and 2 of this publication series clearly illustrate the role of surface chemistry when a substrate is heated to yield atomic or molecular vapors. Depending on the attributes of the substrate material and the extent of surface modification, the surface-induced processes that ultimately define the quantity and the nature of gas phase species includes liquid-solid interactions, solid-solid interactions, catalysis, diffusion, migration, heterogeneous reactions and intercalation.

  15. Tratamento percutâneo de lesões residuais e complicações em condutos de pacientes submetidos a cirurgia de circuito do tipo Fontan / Percutaneous treatment of residual lesions and complications in conduits following Fontan procedure

    Scientific Electronic Library Online (English)

    João Luiz, Manica; André Luis, Bodini; Paulo Renato, Machado; Mônica Scott, Borges; Raul Ivo, Rossi Filho.

    Full Text Available INTRODUÇÃO: A introdução da cirurgia de anastomose cavopulmonar total (ACPT) ou cirurgia de Fontan modificou de forma significativa a história natural de pacientes com cardiopatias complexas não passíveis de reparo biventricular. Entretanto, é conhecido o desenvolvimento de estenoses silenciosas. Al [...] ém disso, a utilização de condutos fenestrados é uma técnica comumente realizada. O presente estudo relata a experiência de um centro terciário no implante percutâneo de dispositivos em condutos de pacientes com circulação do tipo univentricular. MÉTODO: Entre julho de 2000 e julho de 2010, 12 pacientes receberam dispositivos percutâneos em condutos após cirurgia de Fontan. Os pacientes foram divididos em dois grupos, de acordo com a indicação para o procedimento: 5 pacientes receberam implante de oclusores septais para fechamento de fenestração cirúrgica (grupo 1), 6 pacientes receberam stents para alívio de obstrução de condutos (grupo 2), e 1 paciente recebeu ambos os dispositivos simultaneamente. A média de idade dos pacientes do grupo 1 no momento do procedimento era de 174 ± 53,5 meses e o peso médio era de 30,7 ± 6,8 kg. A média de idade dos pacientes do grupo 2 no momento do procedimento era de 148,5 ± 84,6 meses e o peso médio era de 28,9 ± 19,8 kg. RESULTADOS: No grupo 1, a saturação média passou de 82,6 ± 7,5% para 90,4 ± 7,5% logo após o procedimento (P = 0,001). No grupo 2, a saturação média passou de 81,8 ± 8,9% para 91,3 ± 8,7% (P = 0,01). O menor diâmetro do conduto passou de uma média de 6,9 ± 4,8 mm para 16,6 ± 3,5 mm após o procedimento (P = 0,02). O paciente que realizou ambos os procedimentos simultaneamente teve aumento do menor diâmetro do conduto de 11,7 mm para 16 mm e melhora da saturação sistêmica, passando de 60% para 90%. CONCLUSÃO: O tratamento da obstrução de condutos por meio do implante de stents não-recobertos e a oclusão de fenestrações cirúrgicas com stents recobertos ou dispositivos de AmplatzerTM são procedimentos seguros, com altos índices de sucesso imediato e que se mantêm a médio prazo. Abstract in english BACKGROUND: The introduction of total cavopulmonary anastomosis (TCPA) or Fontan procedure significantly changed the natural history of patients with complex heart diseases inadequate for biventricular repair. However, the development of silent stenosis is well known. In addition, fenestrated condui [...] ts are frequently used. The present study reports the experience of a tertiary center with percutaneous devices implanted in the conduits of patients with univentricular circulation. METHOD: From July 2000 to July 2010, 12 patients received percutaneous devices in conduits after Fontan procedure. Patients were divided into two groups, according to the indication for the procedure: 5 patients received septal occluders to close surgical fenestrations (group 1), 6 patients received stents for the relief of conduit obstructions (group 2) and 1 patient received both devices simultaneously. Mean age of group 1 patients at the time of the procedure was 174 ± 53.5 months and mean weight was 30.7 ± 6.8 kg. Mean age of group 2 patients was 148.5 ± 84.6 months and mean weight was 28.9 ± 19.8 kg. RESULTS: In group 1, oxygen saturation rose from 82.6 ± 7.5% to 90.4 ± 7.5% immediately after the procedure (P = 0.001). In group 2, oxygen saturation rose from 81.8 ± 8.9% to 91.3 ± 8.7% (P = 0.01). The minimal conduit diameter changed from 6.9 + 4,8 mm to 16.6 ± 3.5 mm after the procedure (P = 0.02). The patient who was submitted to both procedures simultaneously had an increase of the minimal conduit diameter from 11.7 mm to 16 mm and an improvement in systemic saturation from 60% to 90%. CONCLUSION: Treatment of conduit obstructions with non-covered stents and the occlusion of surgical fenestrations with covered stents or AmplatzerTM devices are safe procedures, with high immediate success rates which are maintained in the mid-term follow-up.

  16. Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

    International Nuclear Information System (INIS)

    Highlights: ? We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. ? Variations on the alkyl chain length n were C3, C5-C7, and C9-C10. ? Enthalpies of vaporization were derived from (p, T) dependencies. ? Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C3, C5-C7, and C9-C10 have been measured by the transpiration method. The molar enthalpies of vaporization ?lgHm of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization ?lgHm (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

  17. Stupéfiants et conduite automobile - les actions réalisées en Belgique Drugs and driving - the Belgian experience

    Directory of Open Access Journals (Sweden)

    Maes Viviane

    2009-03-01

    Full Text Available En mars 1999 une nouvelle loi réprimant la conduite sous influence de drogues illicites a été introduite en Belgique. La procédure légale consiste en a un test de comportement, b un dépistage immunochimique pour 4 groupes de drogues dans les urines c une confirmation par une analyse du plasma (GC-MS avec des seuils fixes. Sur une période de deux ans, l'analyse de 896 échantillons sanguins a révélé la présence de drogues au-dessus du seuil légal dans 85 % des cas. Dans les 15 % de cas “faux positifs” (test de comportement et test urinaire positif sans confirmation dans le plasma, une analyse rétrospective de l'alcool et de médicaments a été entreprise. Dans 36,8 % des cas positifs, seul le THC a été détecté. L'amphétamine et/ou la MDMA étaient présentes au-dessus du seuil dans 32,1 % des cas positifs, et elles étaient combinées au THC dans 11,8 % des cas. La cocaïne et/ou la benzoylecgonine ont été retrouvées dans 18,0 % et la morphine dans 1,4 % des cas positifs. Dans les cas “faux positifs”, 37 % étaient positifs pour l'alcool, et 14 % contenaient des médicaments, surtout des benzodiazépines. Dans notre série, l'abolition du seuil légal aurait réduit les “faux positifs” de 15 à 9 %. En considérant les cas positifs pour l'alcool, il n'y a plus que 7 % de “faux positifs”. Si les médicaments étaient également couverts par la loi, les “faux positifs” seraient réduits de 1 %. In March 1999 a new law prohibiting driving while impaired by illegal drugs was introduced in Belgium. The legal procedure consists of a a field impairment test, b a urine immunoassay for 4 drug groups and c ultimate proof by plasma analysis (GC-MS with fixed cut-offs. Over about two years the analysis of 896 blood samples revealed the presence of illicit drug(s above cut-off in 85 % of the cases. For the 15 % “false positives” (failed impairment test and positive urine assay without confirmation in plasma, retrospective analysis of alcohol and medication was performed. In 36,8 % of the legally positive cases, THC was the only analyte detected. Amphetamine and/or MDMA were present above cut-off in 32,1 % and combined with THC in 11,8 % of all positive samples. Cocaine and/or benzoylecgonine were found in 18,0 % and morphine in 1,4 % of the legally positive cases. In the “false positive” samples 37 % were alcohol-positive, while 14 % contained psychoactive medicines, mostly, benzodiazepines. In the studied population the abolition of the legal cut-off values would have resulted in a decrease of “false positives” from 15 % to 9 %. Considering the additional legally positive alcohol cases a further decrease to 7 % is observed. Including medicinal drugs in the law would have reduced the number of “false positives” by a further 1 %.

  18. An Overview on Thin Films Prepared by Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    Chemical vapor deposition, (CVD); involves the formation of a solid thin layer on a heated substrate surface by means of chemical reaction in gas or vapor phase. CVD techniques have expanded continuously and developed into the most important method for producing films for solid-state devices. CVD is considered to be the major technique for preparing most films used in the fabrication of semiconductor devices and integrated circuits. It has advantages such as the versatility, compatibility, quality, simplicity, reproducibility, and low cost. CVD has some disadvantages of; the use of comparatively high temperatures in many processes and chemical hazards caused by toxic, explosive, or corrosive gases. Chemical vapor deposition processes can be classified according to the type of their activation energy into thermally-activated CVD, plasma-enhanced CVD, laser-induced CVD, photochemical CVD, and electron-beam assisted CVD. In this paper an attempt is made to present all aspects of CVD equipment design and the variables affecting the deposition rate. Finally the preparation requirements and the application of CVD films are also summarized. 5 figs

  19. Simulation of stratospheric water vapor and trends using three reanalyses

    Directory of Open Access Journals (Sweden)

    M. R. Schoeberl

    2012-03-01

    Full Text Available The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011 is extended to the 1979–2010 period. We compare results from NASA's MERRA, NCEP's CFSR, and ECMWF's ERAi reanalyses with HALOE, MLS, and balloon observations. The CFSR based simulation produces a wetter stratosphere than MERRA, and ERAi produces a drier stratosphere than MERRA. We find that ERAi temperatures are cold biased compared to Singapore sondes and MERRA, which explains the ERAi result, and the CFSR grid does not resolve the cold point tropopause, which explains its relatively higher water vapor concentration. The pattern of dehydration locations is also different among the three reanalyses. ERAi dehydration pattern stretches across the Pacific while CFSR and MERRA are concentrate dehydration activity in the West Pacific. CSFR and ERAi also show less dehydration activity in the West Pacific Southern Hemisphere than MERRA. The models' lower stratospheres tend to be dry at high northern latitudes because of too little methane-derived water appears to be descending from the middle stratosphere. Using the tropical tape recorder signal, we find that MERRA vertical ascent is 15% too weak while ERAi is 30% too strong. The models tend to reproduce the observed weakening of the 100-hPa annual cycle in zonal mean water vapor as it propagates to middle latitudes. Finally, consistent with the observations, the models show less than 0.2 ppm decade?1 trends in water vapor both at mid-latitudes and in the tropics.

  20. 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.

    Science.gov (United States)

    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 conduits in the field of nerve tissue engineering. PMID:25580010

  1. Soil vapor extraction with dewatering

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Atomic vapor laser isotope separation

    International Nuclear Information System (INIS)

    Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements

  3. Lattice Boltzmann simulation of solute transport in heterogeneous porous media with conduits to estimate macroscopic continuous time random walk model parameters

    Energy Technology Data Exchange (ETDEWEB)

    Anwar, S.; Cortis, A.; Sukop, M.

    2008-10-20

    Lattice Boltzmann models simulate solute transport in porous media traversed by conduits. Resulting solute breakthrough curves are fitted with Continuous Time Random Walk models. Porous media are simulated by damping flow inertia and, when the damping is large enough, a Darcy's Law solution instead of the Navier-Stokes solution normally provided by the lattice Boltzmann model is obtained. Anisotropic dispersion is incorporated using a direction-dependent relaxation time. Our particular interest is to simulate transport processes outside the applicability of the standard Advection-Dispersion Equation (ADE) including eddy mixing in conduits. The ADE fails to adequately fit any of these breakthrough curves.

  4. A combined discharge nozzle and inlet conduit for the support of an in-vessel heat exchanger in a nuclear reactor

    International Nuclear Information System (INIS)

    The invention deals with an improvement in the way of bringing the feedwater through the wall of the pressure vessel in a PWR type reactor. The feedwater inlet conduit is disposed within the steam discharge nozzle from an in-vessel heat exchanger. The conduit and nozzle combination penetrate the wall of the pressure vessel and support the heat exchanger within the pressure vessel. The invention brings about a cheaper protection against local heat impact on the pressure vessel and improves the bearing structure of the heat exchanger

  5. Vapors-liquid phase separator. [infrared telescope heat sink

    Science.gov (United States)

    Frederking, T. H. K.; Brown, G. S.; Chuang, C.; Kamioka, Y.; Kim, Y. I.; Lee, J. M.; Yuan, S. W. K.

    1980-01-01

    The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase separators for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area variation was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.

  6. Continuously differentiable means

    Directory of Open Access Journals (Sweden)

    Fujii Masatoshi

    2006-01-01

    Full Text Available We consider continuously differentiable means, say -means. As for quasi-arithmetic means , we need an assumption that has no stationary points so that might be continuously differentiable. Introducing quasi-weights for -means would give a satisfactory explanation for the necessity of this assumption. As a typical example of a class of -means, we observe that a skew power mean is a composition of power means if is an integer.

  7. Correction technique for raman water vapor lidar signal dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    Directory of Open Access Journals (Sweden)

    D. N. Whiteman

    2011-12-01

    Full Text Available The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE mobile laboratory in the MOHAVE-2009 campaign. In an appendix we also report on the performance of the corrected Vaisala RS92 radiosonde during the campaign. A new radiosonde based calibration algorithm is presented that reduces the influence of atmospheric variability on the derived calibration constant. The MOHAVE-2009 campaign permitted all Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated revealing that wet biases in upper tropospheric and lower stratospheric water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the data. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most resistant to additional noise sources. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC and elsewhere despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  8. Correction technique for raman water vapor lidar signal dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    Science.gov (United States)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L.; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; Jordan, A.; Vömel, H.

    2011-12-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE mobile laboratory in the MOHAVE-2009 campaign. In an appendix we also report on the performance of the corrected Vaisala RS92 radiosonde during the campaign. A new radiosonde based calibration algorithm is presented that reduces the influence of atmospheric variability on the derived calibration constant. The MOHAVE-2009 campaign permitted all Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated revealing that wet biases in upper tropospheric and lower stratospheric water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the data. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most resistant to additional noise sources. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC and elsewhere despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  9. Water vapor retrieval from OMI visible spectra

    Science.gov (United States)

    Wang, H.; Liu, X.; Chance, K.; González Abad, G.; Miller, C. Chan

    2014-06-01

    There are distinct spectral features of water vapor in the wavelength range covered by the Ozone Monitoring Instrument (OMI) visible channel. Although these features are much weaker than those at longer wavelengths, they can be exploited to retrieve useful information about water vapor. They have an advantage in that their small optical depth leads to fairly simple interpretation as measurements of the total water vapor column density. We have used the Smithsonian Astrophysical Observatory (SAO) OMI operational retrieval algorithm to derive the slant column density (SCD) of water vapor using the 430-480 nm spectral region after extensive optimization. We convert from SCD to vertical column density (VCD) using the air mass factor (AMF), which is calculated using look-up tables of scattering weights and assimilated water vapor profiles. Our Level 2 product includes not only water vapor VCD but also the associated scattering weights and AMF. In the tropics, our standard water vapor product has a median SCD of 1.3 × 1023 molecules cm-2 and a median relative uncertainty of about 11%, about a factor of 2 better than that from a similar OMI algorithm that uses a narrower retrieval window. The corresponding median VCD is about 1.2 × 1023 molecules cm-2. We have examined the sensitivities of SCD and AMF to various parameters and compared our results with those from the GlobVapour product, the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Aerosol Robotic NETwork (AERONET).

  10. Through the volcanic-looking glass: using pyroclastic obsidian to image magma degassing and flow in shallow silicic conduits

    Science.gov (United States)

    Castro, J. M.; Tuffen, H.; Schipper, C.

    2012-12-01

    Obsidian pyroclasts have been widely used to understand magma degassing processes and conduit flow during Plinian eruptions of silicic magma. Recent observations of active rhyolite volcanoes show that obsidian pyroclasts may also erupt during dominantly effusive activity and this raises the question of how might the crystallization, degassing, and cooling histories differ between parcels of magma that become pyroclastic versus effusive obsidian? As the two disparate, yet coeval eruptive styles require different magma ascent conditions, it follows that glassy pyroclasts should record these differences. Here we report on chemical and textural evidence of degassing and crystallization in glassy bombs, pyroclastic lapilli and obsidian lava collected from the recently active Cordón Caulle and Chaitén volcanoes in southern Chile. Coarse obsidian bombs are abundant at both volcanoes and were erupted during large blasts that accompanied lava effusion. Obsidian lapilli are equally ubiquitous in fall deposits and near-vent tuff cones formed during the initial Plinian phases of activity. Total H2O contents and hydrous speciation was measured on these glassy materials by FTIR. The data show two distinct trends, one corresponding to bombs and glassy lavas and characterized by a relative abundance of molecular water and the other associated with the lapilli glasses having relatively elevated OH-. These speciation patterns can be explained by different cooling histories in parcels of magma that had different ascent speeds and residence times in the conduit. The bomb and lava obsidians appear to form of a single Pressure-Temperature-time (P-T-t) path, one that is offset from the Plinian lapilli to lower ascent and cooling rates. These relations suggest that flow in the volcanic conduit is bifurcated and this allows parcels of magma to rise up quickly and fuel sustained pyroclastic columns while other magma can follow more relaxed ascent trajectories allowing it to become proto-lava (Vulcanian bombs) and lava. Analyses of pyroxene microlite size and orientation distributions are currently underway in order to find corroborating evidence of diverse P-T-t paths within pyroclastic and effusive obsidians.

  11. Silver catalyzed ultrathin silicon nanowires grown by low-temperature chemical-vapor-deposition

    Science.gov (United States)

    Wittemann, Joerg V.; Münchgesang, Wolfram; Senz, Stephan; Schmidt, Volker

    2010-05-01

    In this work we demonstrate the synthesis of monocrystalline silicon nanowire using silver particles as catalysts at temperatures of less than 500 °C by means of ultrahigh vacuum chemical vapor deposition. The nanowires were grown epitaxially on silicon substrates and had diameters of about 10 nm. We furthermore show that the silver remnants can be wet chemically removed with potassium ferricyanide and sodium thiosulfate.

  12. Study on trigger mechanism of vapor explosion

    International Nuclear Information System (INIS)

    During severe accident of a light water reactor, various thermal hydraulic phenomena including vapor explosion could threaten the integrity of the containment vessel. The occurrence of the severe accident is extremely unlikely since LWRs are designed based on the defense-in-depth concept. However, it is important to investigate the thermal hydraulic phenomena including vapor explosion in order to evaluate the safety margin and potential risks of the accident management measures to prevent and mitigate the severe accident. Thermal detonation model is proposed to describe the vapor explosion. (author)

  13. Photon path length distributions in Oxygen A-band and water vapor band

    Science.gov (United States)

    Min, Q.; Harrison, L. C.; Kiedron, P.; Berndt, J.; Clothiaux, E. E.; Joseph, E.

    2004-05-01

    A prototype high-resolution oxygen A-band and water vapor band spectrometer (HAWS) has been developed and demonstrated to study the applicability of photon path length statistics in the remote sensing of clouds, aerosols, and water vapor. The HAWS successfully achieves an out-of-band rejection of better than 10-5, a resolution of better than 0.5 cm-1, and high signal to noise ratio, which are crucial to retrieval of atmospheric information through high-resolution spectrometry in the A-band and water vapor band. An algorithm for retrieving the first two moments of the photon path length probability density function for both the oxygen A-band and the 0.820 mm water vapor band from measurements of HAWS and Rotating Shadowband Spectrometer (RSS) is developed and applied to data from the ARM SGP site. Results show that in the A-band thick and multiple layer clouds significantly enhance the mean and variance of the photon path length distribution, thin cirrus condition produce relatively small mean distribution and variance, and mean path lengths comparable to or smaller than the solar airmass were associated with clear sky cases at large solar zenith angles. The mean path length and variance in the water vapor band differs from that in the A-band due to the spatial inhomogeneity of water vapor amounts, particularly in association with cloud layers. Case studies illustrate that the variance of the photon path length probability density function is more sensitive than the mean of the probability density function to vertical cloud structure. Interestingly, the first two moments of the photon path length probability density function appear to exhibit sufficient sensitivity to detect cirrus that the ARM SGP millimeter-wave cloud radar failed to detect. Photon path length probability density functions from both the oxygen A-band and 0.820 mm water vapor band provide additional insights into radiative transfer through a variety of cloudy conditions, improving our understanding of water vapor absorption of solar radiation in these conditions. This work also provides a basis for the application of path length distribution in the development and validation of radiative transfer parameterizations that account for the effects of cloud inhomogeneity.

  14. Conduites addictives en milieu professionnel : aspects réglementaires Addiction at the workplace: legal aspects

    Directory of Open Access Journals (Sweden)

    Frimat Paul

    2009-04-01

    Full Text Available Est-il raisonnable de confier des vies humaines à un sujet en état d'ivresse ou sous l'emprise de stupéfiants ou de médicaments agissant sur le système nerveux ? L'entreprise est directement concernée par les conduites addictives. Le médecin du travail doit agir dans le cadre de l'hygiène et de la sécurité en s'appuyant sur des bases juridiques tout en respectant la déontologie. Cette dernière est claire, l'aspect juridique l'est moins mais certainement suffisant pour agir. La responsabilité du médecin est engagée. Il doit tout mettre en oeuvre pour prévenir et faire cesser immédiatement une situation faisant encourir un danger particulier au salarié, à ses collègues de travail, à la collectivité et à l'environnement. Les dispositions légales sont les suivantes : Le Code Pénal (loi sur les stupéfiants du 31/13/1970, le Code de la Santé Publique (Art. L. 623 à L. 630, le Code de Déontologie (secret professionnel, le Code du Travail : si le dépistage des substances toxicomanogènes n'est pas précisé, le médecin dispose de nombreux moyens pour répondre : que ce soit dans son rôle de conseiller (article R. 241-41 ou dans la procédure d'aptitude (article R. 241-48 à 51. Le médecin du travail peut agir face au problème de la toxico-manie (circulaire n° 90/13 du 9 juillet 1990, le Code des Transports (délivrance du permis de conduire : L'arrêté du 7/05/97 (JO du 29/05/97 fixe la liste des incapacités physiques incompatibles avec l'obtention ou le maintien du permis de conduire. Depuis le décret du 27 août 2001 et l'arrêté du 5 septembre 2001, la recherche de stupéfiants doit être pratiquée sur les conducteurs impliqués dans un accident mortel. L'article 21 de la loi du 15 novembre 2001 relative à la sécurité quotidienne souligne le fait que les officiers de police judiciaire peuvent également faire procéder à cette recherche en cas d'accident corporel. En pratique, il existe des droits et limites. La toxicomanie multiplie le risque de troubles du comportement, d'absentéisme, d'accident, de baisse de la vigilance. Dans le cadre des missions du médecin du travail, le dépistage éventuel des «dépendances» en entreprise ne doit pas conduire à une sélection, mais doit se placer dans une démarche de prévention. Le règlement intérieur doit rappeler l'interdiction de détention et d'usage de substances illicites au sein de l'entreprise et l'obligation de respecter les examens exigés par le médecin du travail, notamment pour les postes à risque. Il est indispensable d' adopter au sein de l'entreprise une attitude cohérente et une très large concertation avec la direction, les délégués du personnel et les CHS-CT. Il faut multiplier les campagnes d'information et créer des cellules de prévention. Le médecin traitant est régulièrement confronté à la toxicomanie, il se doit de la prendre en charge. Le médecin du travail a le devoir de s'intéresser à ce phénomène dont les conséquences sont multiples pour la santé et la sécurité de l'individu, de l'entreprise et de la collectivité. Is it reasonable to confide human lives to people in drunken state or under drug or medicine ascendancy ? Today, the workplace is directly affected by drug addiction. The occupational physician has to act in the field of hygiene and security, using the juridical basis and according to the deontology. His responsibility is engaged. He must implement everything , in order to prevent or to make cease immediately a situation dangerous for a worker, his colleagues, the collectivity and the environment. Legal disposition are numerous and French laws approaching the question of addiction are the following : the Penal code (law on drugs, 31/13/1970 ; the Public Health Code (Art L. 623 to L. 630 ; the Deontology Code (professional secret ; the Occupational Code : even if the tracking of drug is not well specified, the physician can act face to the problem of drug addiction (circulaire n° 90/13 of 09/07/1990, especially by playing his part of adviser (Art R 241

  15. Experiments on rheology of non-Newtonian flow of tylose-alginate suspension through a horizontal complex conduit

    International Nuclear Information System (INIS)

    Experiments were conducted on rheological behavior of pseudoplastic non-Newtonian tylose-alginate (solid-liquid) suspensions in isothermal laminar flow in a horizontal conduit with variable geometry. The complex flow of loaded spherical and large-sized particles of 4.4 mm diameter, and dependence of hydrodynamics of organoleptic quality of the loaded fluids governed by Ostwald power law were investigated. The geometry of the horizontal pipe of variable cross-section provided turbulence promoters for fluid flow which generated backflow zones for homogenizing the suspensions by improved mixing quality. The consistency index (K) increased with the volume traction of solid particles, but decreased with temperature; and for a net change in viscosity of 0.75 % tylose concentrated solution, K increased with temperature of the carrier fluid. The structure index, n, varied with the concentration of the hard spheres, but did not vary substantially with temperature. (au)

  16. Three-dimensional fluid mechanics of particulate two-phase flows in U-bend and helical conduits

    Science.gov (United States)

    Tiwari, Prashant; Antal, Steven P.; Podowski, Michael Z.

    2006-04-01

    The results of numerous studies performed to date have shown that the performance of various hydraulic systems can be significantly improved by using curved conduit geometries instead of straight tubes. In particular, the formation of Dean vortices, which enhance the development of centrifugal instabilities, has been identified as a factor behind reducing the near-wall concentration buildup in particulate flow devices (e.g., in membrane filtration modules). Still, several issues regarding the effect of conduit curvature on local multidimensional phenomena governing fluid flow still remain open. A related issue is concerned with the impact that conduit geometry makes on the concentration distribution of a dispersed phase in two-phase flows in general, and in particulate flows (solid/liquid or solid/gas suspensions) in particular. It turns out that only very limited efforts have been made in the past to understand the fluid mechanics of such flows via advanced computer simulations. The purpose of this paper is to present the results of full three-dimensional (3D) theoretical and numerical analyses of single- and two-phase dilute particle/liquid flows in U-bend and helical curved conduits. The numerical analysis is based on computational fluid dynamics (CFD) simulations performed using a state-of-the-art multiphase flow computer code, NPHASE. The major issues discussed in the first part of the paper are concerned with the effect of curved/coiled geometry on the evolution of flow field and the associated wall shear. It has been demonstrated that the primary curvature (a common factor for both the U-bend and helix geometries) may cause a substantial asymmetry in the radial distribution of the main flow velocity. This, in turn, leads to a significant, albeit highly nonuniform, increase in the wall shear stress. Specifically, the wall shear around the outer half of tube circumference may become twice the corresponding value for a straight tube, and gradually decrease to the straight tube level when approaching the inner bend location. Another important issue is concerned with the effect of the length of the curved section and of the straight tube just upstream of the bend. Specifically, the discontinuity in curvature at the straight-to-curved transition location results in a localized change in the wall shear distribution around the tube circumference. On the other hand, if the curved tube is sufficiently long, such as in the case of a helix, the asymmetric velocity profile eventually reaches a fully developed pattern. The effect of nondimensional flow parameters, the Reynolds and Dean numbers, on the entry length along the curved helix geometry is also investigated in this paper. It is shown that the predicted developing length agrees well with the existing experimental data. The objective of the second part of the paper is to investigate the mutual interactions between the liquid flow and solid particles in particulate two-phase flows in both the U-bend and helical geometries. It is shown that particle inertia causes an increase in the wall shear. At the same time, two interesting aspects are shown of Dean vortices on particle concentration under the effect of gravity. One of them is the shift in the particle settling zone from the bottom of the horizontal (or nearly horizontal) tube toward the inner bend of the tube. The other, even more important, is a dramatic reduction in peak concentration with increasing Dean number. Both effects are important for equipment design and optimization in biotechnology and process industries.

  17. Comparaison des conduites discursives de mères et d’enseignants dans la co-construction de récits avec des enfants

    Directory of Open Access Journals (Sweden)

    Vinel Elise

    2014-07-01

    Full Text Available Cette communication s’intéresse aux conduites discursives produites par des mères et des enseignants au cours de deux lectures conjointes d’album avec des enfants. Elle s’inscrit dans une approche dialogique et interactionniste du langage. Dans la suite des travaux de Florin (1991, Grossmann (1996, analysant les styles d’interaction des enseignants et de réception des enfants en cours de lecture, mais aussi de ceux de Vygotski (1984, Bruner (1994 ou encore Salazar Orvig et De Weck (2014, nous cherchons à comprendre de quelles manières les adultes racontent des histoires aux enfants et à quelles expériences spécifiques des récits ceux-ci sont confrontés. Dix enfants âgés de 3 à 5 ans ont été filmés au cours de ces séances de lectures d’albums, sans texte et avec texte, avec un de leur parent à leur domicile et avec des pairs et des enseignants à l’école.

  18. Probe for measurement of velocity and density of vapor in vapor plume

    Science.gov (United States)

    Berzins, Leon V. (Livermore, CA); Bratton, Bradford A. (Bethel Island, CA); Fuhrman, Paul W. (Livermore, CA)

    1997-01-01

    A probe which directs a light beam through a vapor plume in a first direction at a first angle ranging from greater than 0.degree. to less than 90.degree., reflecting the light beam back through the vapor plume at a 90.degree. angle, and then reflecting the light beam through the vapor plume a third time at a second angle equal to the first angle, using a series of mirrors to deflect the light beam while protecting the mirrors from the vapor plume with shields. The velocity, density, temperature and flow direction of the vapor plume may be determined by a comparison of the energy from a reference portion of the beam with the energy of the beam after it has passed through the vapor plume.

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

    Science.gov (United States)

    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. PMID:24034829

  20. Design and synthesis of elastin-like polypeptides for an ideal nerve conduit in peripheral nerve regeneration

    International Nuclear Information System (INIS)

    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

  1. Design and synthesis of elastin-like polypeptides for an ideal nerve conduit in peripheral nerve regeneration

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Dynamics within geyser conduits, and sensitivity to environmental perturbations: insights from a periodic geyser in the El Tatio Geyser Field, Atacama Desert, Chile

    Science.gov (United States)

    Munoz-Saez, Carolina; Manga, Michael; Hurwitz, Shaul; Rudolph, Maxwell L.; Namiki, Atsuko; Wang, Chi-Yuen

    2015-01-01

    Despite more than 200 years of scientific study, the internal dynamics of geyser systems remain poorly characterized. As a consequence, there remain fundamental questions about what processes initiate and terminate eruptions, and where eruptions begin. Over a one-week period in October 2012, we collected down-hole measurements of pressure and temperature in the conduit of an exceptionally regular geyser (132 s/cycle) located in the Chilean desert. We identified four stages in the geyser cycle: (1) recharge of water into the conduit after an eruption, driven by the pressure difference between water in the conduit and in a deeper reservoir; (2) a pre-eruptive stage that follows the recharge and is dominated by addition of steam from below; (3) the eruption, which occurs by rapid boiling of a large mass of water at the top of the water column, and decompression that propagates boiling conditions downward; (4) a relaxation stage during which pressure and temperature decrease until conditions preceding the recharge stage are restored. Eruptions are triggered by the episodic addition of steam coming from depth, suggesting that the dynamics of the eruptions are dominated by geometrical and thermodynamic complexities in the conduit and reservoir. Further evidence favoring the dominance of internal processes in controlling periodicity is also provided by the absence of responses of the geyser to environmental perturbations (air pressure, temperature and probably also Earth tides).

  3. Peripheral nerve reconstruction with epsilon-caprolactone conduits seeded with vasoactive intestinal peptide gene-transfected mesenchymal stem cells in a rat model

    Science.gov (United States)

    Hernández-Cortés, P.; Toledo-Romero, M. A.; Delgado, M.; Sánchez-González, C. E.; Martin, F.; Galindo-Moreno, P.; O'Valle, F.

    2014-08-01

    Objective. Attempts have been made to improve nerve conduits in peripheral nerve reconstruction. We investigated the potential therapeutic effect of a vasoactive intestinal peptide (VIP), a neuropeptide with neuroprotective, trophic and developmental regulatory actions, in peripheral nerve regeneration in a severe model of nerve injury that was repaired with nerve conduits. Approach. The sciatic nerve of each male Wistar rat was transected unilaterally at 10 mm and then repaired with Dl-lactic-?-caprolactone conduits. The rats were treated locally with saline, with the VIP, with adipose-derived mesenchymal stem cells (ASCs) or with ASCs that were transduced with the VIP-expressing lentivirus. The rats with the transected nerve, with no repairs, were used as untreated controls. At 12 weeks post-surgery, we assessed their limb function by measuring the ankle stance angle and the percentage of their muscle mass reduction, and we evaluated the histopathology, immunohistochemistry and morphometry of the myelinated fibers. Main results. The rats that received a single injection of VIP-expressing ASCs showed a significant functional recovery in the ankle stance angle (p = 0.049) and a higher number of myelinated fibers in the middle and distal segments of the operated nerve versus the other groups (p = 0.046). Significance. These results suggest that utilization of a cellular substrate, plus a VIP source, is a promising method for enhancing nerve regeneration using Dl-lactic-?-caprolactone conduits and that this method represents a potential useful clinical approach to repairing peripheral nerve damage.

  4. Dynamics within geyser conduits, and sensitivity to environmental perturbations: Insights from a periodic geyser in the El Tatio geyser field, Atacama Desert, Chile

    Science.gov (United States)

    Munoz-Saez, Carolina; Manga, Michael; Hurwitz, Shaul; Rudolph, Maxwell L.; Namiki, Atsuko; Wang, Chi-Yuen

    2015-02-01

    Despite more than 200 years of scientific study, the internal dynamics of geyser systems remain poorly characterized. As a consequence, there remain fundamental questions about what processes initiate and terminate eruptions, and where eruptions begin. Over a one-week period in October 2012, we collected down-hole measurements of pressure and temperature in the conduit of an exceptionally regular geyser (132 s/cycle) located in the Chilean desert. We identified four stages in the geyser cycle: (1) recharge of water into the conduit after an eruption, driven by the pressure difference between water in the conduit and in a deeper reservoir; (2) a pre-eruptive stage that follows the recharge and is dominated by addition of steam from below; (3) the eruption, which occurs by rapid boiling of a large mass of water at the top of the water column, and decompression that propagates boiling conditions downward; and (4) a relaxation stage during which pressure and temperature decrease until conditions preceding the recharge stage are restored. Eruptions are triggered by the episodic addition of steam coming from depth, suggesting that the dynamics of the eruptions are dominated by geometrical and thermodynamic complexities in the conduit and reservoir. Further evidence favoring the dominance of internal processes in controlling periodicity is also provided by the absence of responses of the geyser to environmental perturbations (air pressure, temperature and probably also Earth tides).

  5. Cirurgia coronária com condutos arteriais múltiplos sem circulação extracorpórea / Off-pump coronary artery bypass with multiple arterial conduits

    Scientific Electronic Library Online (English)

    Daniel, Navia; Mariano, Vrancic; Guillermo, Vaccarino; Fernando, Piccinini; Eduardo, Iparraguirre; Marcelo, Casas; Jorge, Thierer.

    2005-03-01

    Full Text Available OBJETIVO: Analisar os resultados, em 30 dias, em pacientes submetidos de forma eletiva à revascularização arterial total do miocárdio sem circulação extracorpórea (CEC), e identificar preditores de morbimortalidade com esta estratégia cirúrgica. MÉTODO: Entre maio de 1999 e fevereiro de 2004, efetua [...] ram-se 203 cirurgias de revascularização miocárdica (CRM) com revascularização arterial total sem CEC, em pacientes com doença de múltiplos vasos (três vasos 81,7%, doença de um vaso excluída). Reportaram-se variáveis pré-operatórias e comorbidade: média de idade 63,9 ± 9,13 anos, homens 182 (89,5%), hipertensão 132 (65%), tabagismo 125 (61%), hipercolesterolemia 152 (74,8%), infarto agudo do miocárdio prévio (mais de 30 dias) 73 (35%), disfunção ventricular moderada a grave 31 (15%), reoperação cinco (2,5%). A revascularização arterial total incluiu anastomoses em T e seqüenciais com artéria torácica interna esquerda (100%), torácica interna direita (56,6%) e artéria radial (63%). O número total de anastomoses foi 576 (média de três pontes/paciente), todas efetuadas com estabilizadores mecânicos externos. Não form realizadas anastomoses proximais na aorta. Cirurgia com CEC foi realizada em três (1,5%) pacientes. Noventa por cento dos pacientes foram extubados na sala de operações. Para a análise estatística, utilizou-se teste de regressão logística múltipla. RESULTADOS: A incidência de fibrilação atrial pós-operatória foi de 12,8% (26), insuficiência renal oligoanúrica 3% (seis), diálise 0,49% (um), infarto de miocárdio pós-operatório 1,47% (três), baixo débito cardíaco 4% (oito), reoperação por sangramento 1,47% (três), mediastinite 1,47% (três), acidente vascular cerebral 1,47% (três). A mortalidade intra-hospitalar foi de 2,45% (cinco). O único preditor independente de morbidade em 30 dias foi a idade (p=0,033; OR 1,04; IC 95%: 1-1,08). CONCLUSÃO: A cirurgia de revascularização miocárdica sem circulação extracorpórea utilizando condutos arteriais para a doença de múltiplos vasos é factível com baixa morbimortalidade em 30 dias. Abstract in english OBJECTIVE: To analyze intra-hospital results in patients undergoing elective off-pump total arterial revascularization and identify morbidity and mortality predictors using this surgical strategy. METHOD: From May 1999 to February 2004, 203 myocardial revascularization procedures with total arterial [...] revascularization without cardiopulmonary bypass (off-pump) were carried out in patients with multivessel disease (three vessels 81.7 %, one vessel disease was excluded). We report pre-surgical variables and co-morbidities: average age 63.9 ± 9.13 years, men 182 (89.5%), hypertension 132 (65%), smokers 125 (61%), hypercholesterolemia 152 (74.8%), previous myocardial infarction (> 30 days) 73 (35%), moderate to severe ventricular dysfunction 31 (15%), redo five (2.5%). Total arterial revascularization included T-grafts and sequential grafts with left internal mammary (100%), right internal mammary (56.6%) and radial (63%) arteries. The total number of distal anastomosis was 576 (mean of three grafts/patient), all carried out with external mechanical stabilizers. There were no proximal aortic anastomoses. Conversion to on-pump surgery occurred in three (1.5%) patients; 90% of the patients was extubated in the operating room. The multiple logistic regression test was used for statistical analysis. RESULTS: The postoperative incidence of atrial fibrillation was 12.8% (26), oligoanuric renal failure 3% (six), dialysis 0.49% (one), postoperative myocardial infarction 1.47% (three), low cardiac output 4% (eight), Redo for bleeding 1.47% (three), mediastinitis 1.47% (three), stroke 1.47% (three). Intra-hospital mortality was 2.45% (five). The only independent 30 day morbidity predictor was age (p=0.033; OR 1.04; IC 95%: 1-1.08). CONCLUSION: Off-pump myocardial revascularization with arterial conduits for multiple vessel disease is feasible with a low 30-day morbidity and mortal

  6. A device for sealing the dead end sectors of mine water conduits

    Energy Technology Data Exchange (ETDEWEB)

    Privalov, N.I.; Akselrod, V.M.; Romanchuk, A.L.

    1983-01-01

    To increase the operational reliability when used on fire suppressing and irrigating pipelines, a branch pipe, equipped on one end with a lattice, is attached to the corresponding flange coaxially. The cavity of the branch pipe is filled with an easily melted material, while the seal is connected with the lattice by means of a spring.

  7. Internalized Meaning Factualism

    DEFF Research Database (Denmark)

    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 are defended by, e.g., Robert Brandom, Paul Horwich and Huw Price), that promises to solve the problems. According to this position, the problem of meaning can be solved by prohibiting an external perspective on meaning constituting properties. The idea is that if we stick to a perspective on meaning 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 factualism is unstable. The problems about the normativity of meaning can therefore not be sidestepped in this way.

  8. Isolating the Ricochet-induced Vaporization Process

    Science.gov (United States)

    Schultz, P. H.; Sugita, S.; Eberhardy, C. A.; Ernst, C. M.

    2004-03-01

    Experiments were designed to isolate the ricochet contribution to impact-generated vaporization of calcium carbonate. High-speed spectroscopy reveals that downrange impacts by the ricocheting projectile play a significant role.

  9. GOES WATER VAPOR TRANSPORT V1

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products spanning the 1987/1988 El Nino Southern Oscillation (ENSO)...

  10. Vaporization of Samarium trichloride studied by thermogravimetry

    International Nuclear Information System (INIS)

    In the present work, the vaporization reaction of SmCl3(l) obtained from the 'in situ' reaction of Sm2O3(s) and Cl2(g)-C(s) was studied by thermogravimetry under controlled atmosphere. The effects of both the temperature between 825 C degrees and 950 C degrees and the total flow gas on the vaporization rate of the following reaction: SmCl3(l) = SmCl3(g) were analyzed. The vaporization rate of the process was found to be independent of then total gas flow rate and highly dependent on the temperature. Eap calculation led to a value of 240 ± 10 kJ.mol-1. A comparison between this value and that of the molar enthalpy of vaporization allow to the conclusion that the reaction occur in conditions near to equilibrium. The SmCl3 identity was determined by X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). (author)

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

    Science.gov (United States)

    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. PMID:17902946

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

    International Nuclear Information System (INIS)

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 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

  13. Uranium dioxide vapor condensation by rarefaction waves in the ORNL Capacitor Discharge Vaporization tests

    International Nuclear Information System (INIS)

    A spherical shock tube type model with homogeneous nucleation and particle condensation growth in the rarefaction wave fan has been developed and applied to the Capacitor Discharge Vaporization (CDV) experiments conducted at ORNL. In each CDV test, a stack of molten UO2 fuel pellets contained in a quartz tube were partially vaporized in an argon environment by rapid energy deposition through capacitor discharge. A UO2 aerosol was generated during the resulting expansion of the UO2 vapor. The position of the expanding UO2 vapor-argon interface as a function of time was estimated from movies of the CDV tests

  14. Vapor pressures and enthalpies of vaporization of a series of ? and ?-lactones by correlation gas chromatography

    International Nuclear Information System (INIS)

    Highlights: • The vaporization enthalpies of ?-octanolactone, ?- and ?-undecanolactone and ? and ?-dodecanolactone are reported. • Equations for predicting the vapor pressures over the temperature range T = (298.15 to 350) K are provided. • Vaporization enthalpies are compared to predicted values. - Abstract: The vaporization enthalpies of ?-octanolactone, ?- and ?-undecanolactone and ? and ?-dodecanolactone used commercially as flavor ingredients are reported as are their vapor pressures over the temperature range T = (298.15 to 350) K. Vaporization enthalpies at T = 298.15 K of: (66.0 ± 3.9), (79.4 ± 4.4), (80.1 ± 4.5), (83.9 ± 4.6), and (84.61 ± 4.7) kJ · mol?1 and vapor pressures also at T = 298.15 K of: (2.8 ± 0.9), (0.12 ± 0.05), (0.09 ± 0.04), (0.04 ± 0.02), and (0.03 ± 0.02) Pa, respectively, have been evaluated by correlation gas chromatography experiments. The vaporization enthalpies of the lactones studied are reproduced within ±0.5 kJ · mol?1 using a group additivity scheme reported previously for ?- and ?-lactones. The vaporization enthalpies of the ?- and ?-lactones are compared to a similar series of ?-lactones

  15. Vapor wall deposition in Teflon chambers

    Science.gov (United States)

    Zhang, X.; Schwantes, R. H.; McVay, R. C.; Lignell, H.; Coggon, M. M.; Flagan, R. C.; Seinfeld, J. H.

    2015-04-01

    Teflon chambers are ubiquitous in studies of atmospheric chemistry. Secondary organic aerosol (SOA) formation can be underestimated, owing to deposition of SOA-forming vapors to the chamber wall. We present here an experimental protocol and a model framework to constrain the vapor-wall interactions in Teflon chambers. We measured the wall deposition rates of 25 oxidized organic compounds generated from the photooxidation of isoprene, toluene, ?-pinene, and dodecane in two chambers that had been extensively used and in two new unused chambers. We found that the extent of prior use of the chamber did not significantly affect the sorption behavior of the Teflon films. Among the 25 compounds studied, the maximum wall deposition rate is exhibited by the most highly oxygenated and least volatile compounds. By optimizing the model output to the observed vapor decay profiles, we identified that the dominant parameter governing the extent of wall deposition of a compound is its wall accommodation coefficient (?wi), which can be correlated through its volatility with the number of carbons and oxygens in the molecule. By doing so, the wall-induced deposition rate of intermediate/semi-volatile organic vapors can be reasonably predicted based on their molecular constituency. The extent to which vapor wall deposition impacts measured SOA yields depends on the competition between uptake of organic vapors by suspended particles and the chamber wall. The timescale associated with vapor wall deposition can vary from minutes to hours depending on the value of ?w,i. For volatile and intermediate volatility organic compounds (small ?w,i), gas-particle partitioning will dominate wall deposition for typical particle number concentrations in chamber experiments. For compounds characterized by relatively large ?w,i, vapor transport to particles is suppressed by competition with the chamber wall even with perfect particle accommodation.

  16. Water vapor distribution in protoplanetary disks

    International Nuclear Information System (INIS)

    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 Ly? photons, since the Ly? 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 extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column density of warm water vapor can be as high as 1022 cm–2. A small amount of hot water vapor with temperature higher than ?300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.

  17. Metal Vapor Arcing Risk Assessment Tool

    Science.gov (United States)

    Hill, Monika C.; Leidecker, Henning W.

    2010-01-01

    The Tin Whisker Metal Vapor Arcing Risk Assessment Tool has been designed to evaluate the risk of metal vapor arcing and to help facilitate a decision toward a researched risk disposition. Users can evaluate a system without having to open up the hardware. This process allows for investigating components at risk rather than spending time and money analyzing every component. The tool points to a risk level and provides direction for appropriate action and documentation.

  18. Effect of impact angle on vaporization

    Science.gov (United States)

    Schultz, Peter H.

    1996-09-01

    Impacts into easily vaporized targets such as dry ice and carbonates generate a rapidly expanding vapor cloud. Laboratory experiments performed in a tenuous atmosphere allow deriving the internal energy of this cloud through well-established and tested theoretical descriptions. A second set of experiments under near-vacuum conditions provides a second measure of energy as the internal energy converts to kinetic energy of expansion. The resulting data allow deriving the vaporized mass as a function of impact angle and velocity. Although peak shock pressures decrease with decreasing impact angle (referenced to horizontal), the amount of impact-generated vapor is found to increase and is derived from the upper surface. Moreover, the temperature of the vapor cloud appears to decrease with decreasing angle. These unexpected results are proposed to reflect the increasing roles of shear heating and downrange hypervelocity ricochet impacts created during oblique impacts. The shallow provenance, low temperature, and trajectory of such vapor have implications for larger-scale events, including enhancement of atmospheric and biospheric stress by oblique terrestrial impacts and impact recycling of the early atmosphere of Mars.

  19. Sexual Function after Non-Nerve-Sparing Radical Cystoprostatectomy: A Comparison between Ileal Conduit Urinary Diversion and Orthotopic Ileal Neobladder Substitution

    Scientific Electronic Library Online (English)

    M.A, Asgari; M.R, Safarinejad; N, Shakhssalim; M, Soleimani; A, Shahabi; E, Amini.

    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 enroll [...] ed 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.

  20. Cauchy Mean Theorem

    Directory of Open Access Journals (Sweden)

    Grabowski Adam

    2015-02-01

    Full Text Available The purpose of this paper was to prove formally, using the Mizar language, Arithmetic Mean/Geometric Mean theorem known maybe better under the name of AM-GM inequality or Cauchy mean theorem. It states that the arithmetic mean of a list of a non-negative real numbers is greater than or equal to the geometric mean of the same list.

  1. Vapor Hydrogen Peroxide Sterilization Certification

    Science.gov (United States)

    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 presented.

  2. 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)

    Energy Technology Data Exchange (ETDEWEB)

    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)

  3. Outcome of Transurethral Plasmakinetic Vaporization for Benign Prostatic Hyperplasia

    Scientific Electronic Library Online (English)

    Magdy, El-Tabey; Ahmed, Abo-Taleb; Ashraf, Abdelal; Mostafa Mahmod, Khalil.

    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 Intern [...] ational 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

  4. Deuterium excess in subtropical free troposphere water vapor: Continuous measurements from the Chajnantor Plateau, northern Chile

    Science.gov (United States)

    Samuels-Crow, Kimberly E.; Galewsky, Joseph; Sharp, Zachary D.; Dennis, Kate J.

    2014-12-01

    Water vapor measured continuously by cavity ring-down spectroscopy from July 2012 to March 2013 on the hyperarid Chajnantor Plateau, northern Chile (elevation = 5080 m, pressure ? 550 hPa), has a mean deuterium excess (d-excess = ?D - 8*?18O) of 46‰ ± 5‰ and frequently exceeds 100‰ at low water vapor mixing ratios (q ? 500 ppmv). These measurements provide empirical support for theoretical predictions of free troposphere d-excess. The d-excess measured at this site can be understood in terms of supersaturation with respect to ice at relative humidities between 100% and 130%, followed by mixing with moist midtropospheric or lower tropospheric air en route to the plateau. The d-excess measured at Chajnantor is consistent with predictions for d-excess in the upper troposphere from isotope-enabled general circulation models and with high vapor saturation over ice in cloud-resolving and microphysical models.

  5. Monsoon onset signal in the stable oxygen and hydrogen isotope ratios of monsoon vapor

    Science.gov (United States)

    Srivastava, Rohit; Ramesh, R.; Gandhi, Naveen; Jani, R. A.; Singh, Ashutosh K.

    2015-05-01

    Whereas data on deuterium (D) and oxygen (18O), effective tracers of hydrological processes, are available for global precipitation, such data on atmospheric water vapor are limited. With the advent of satellites capable of measuring D in atmospheric water vapor, mesoscale moisture transport processes (e.g. monsoons) could be detected early provided the signal is well above the noise. Our results of daily measurements of stable oxygen and hydrogen isotopic compositions of atmospheric water vapor (?18Ovapor, ?Dvapor) and rain (?18Orain, ?Drain) during 2007-2008 CE over Ahmedabad, India, show that this is indeed so: (i) the onset of monsoon is marked by a dramatic decrease of ?2.9‰ and ?60‰, in ?18Ovapor, ?Dvapor, respectively, and 46‰ in deuterium excess (?D - 8. ?18O) of local atmospheric water vapor (ii) ?18Ovapor, ?Dvapor, ?18Orain and ?Drain exhibit correlated variations during the monsoon season (mid-June to mid-September): the daily variations of ?18Ovapor and ?Dvapor are higher during large rain events, with sharp negative excursions from mean values. Deuterium excess of vapor and rain are indistinguishable from each other, within their natural variability, consistent with the achievement of isotopic equilibrium between them.

  6. Application of a new multiphase multicomponent volcanic conduit model with magma degassing and crystallization to Stromboli volcano.

    Science.gov (United States)

    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 reproduce both effusive and explosive eruptive activities at Stromboli volcano. Three different crystal components (olivine, pyroxene and feldspar) and two different gas species (water and carbon dioxide) are taken into account. The equilibrium profiles of crystallization as function of pressure, temperature and water content are modeled using the numerical codes AlphaMELTS and DAKOTA. The equilibrium of dissolved gas content, instead, is obtained using a non-linear fitting of data computed using VolatileCALC. With these data, we simulate numerically the lava effusion that occurred at Stromboli between 27 February and 2 April 2007, and find good agreement with the observed data (vesicularity, exsolved gas composition, crystal content and mass flow rate) at the vent. We find that the model is highly sensitive to input magma temperature, going from effusive to explosive eruption with temperature changes by just 20 °C. We thoroughly investigated through a sensitivity analysis the control of the temperature of magma chamber and of the radius of the conduit on the mass flow rate, obtaining also a set of admissible temperatures and conduit radii that produce results in agreement with the real observations.

  7. A mean spherical approximation study of phase stability in charged colloidal solutions

    OpenAIRE

    Caccamo, C.

    1993-01-01

    The phase stability of charged hard sphere fluid mixtures modelling colloidal solutions is studied through the Mean Spherical Approximation (MSA). The isothermal compressibility and the Gibbs free energy of mixing are calculated, and from them, the liquid-vapor and the liquid-liquid decomposition spinodal line are determined, respectively. The MSA results favorably compare with those available from other theories as far as the liquid-vapor instabiity is concerned. For liquid-liquid decomposit...

  8. Thirty Meter Telescope Site Testing X: Precipitable Water Vapor

    Science.gov (United States)

    Otárola, A.; Travouillon, T.; Schöck, M.; Els, S.; Riddle, R.; Skidmore, W.; Dahl, R.; Naylor, D.; Querel, R.

    2010-04-01

    The results of the characterization of precipitable water vapor in the atmospheric column carried out in the context of identifying potential sites for the deployment of the Thirty Meter Telescope (TMT) are presented. Prior to starting the dedicated field campaign to look for a suitable site for the TMT, candidate sites were selected based on a climatology report utilizing satellite data that considered water vapor as one of the study variables. These candidate sites are all of tropical or subtropical location at geographic areas dominated by high-pressure systems. The results of the detailed on-site study, spanning a period of 4 yr, from early 2004 until the end of 2007, confirmed the global mean statistics provided in the previous reports based on satellite data, and also confirmed that all the candidate sites are exceptionally good for astronomy research. At the locations of these sites, the atmospheric conditions are such that the higher the elevation of the site, the drier it gets. However, the data analysis shows that during winter, San Pedro Mártir, a site about 230 m lower in elevation than Armazones, is drier than the Armazones site. This finding is attributed to the fact that Earth's atmosphere is largely unsaturated, leaving room for regional variability; it is useful in illustrating the relevance of in situ atmospheric studies for understanding the global and seasonal variability of potential sites for astronomy research. The results also show that winter and spring are the driest seasons at all of the tested sites, with Mauna Kea (in the northern hemisphere) and Tolonchar (in the southern hemisphere) being the tested sites with the lowest precipitable water vapor in the atmospheric column and the highest atmospheric transmission in the near and mid-infrared bands. This is the tenth article in a series discussing the TMT site-testing project.

  9. Simulation of stratospheric water vapor and trends using three reanalyses

    Directory of Open Access Journals (Sweden)

    M. R. Schoeberl

    2012-07-01

    Full Text Available The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011 is extended to the 1979–2010 period. We compare results from NASA's MERRA, NCEP's CFSR, and ECMWF's ERAi reanalyses with HALOE, MLS, and balloon observations. The CFSR based simulation produces a wetter stratosphere than MERRA, and ERAi produces a drier stratosphere than MERRA. We find that ERAi 100 hPa temperatures are cold biased compared to Singapore sondes and MERRA, which explains the ERAi result, and the CFSR grid does not resolve the cold point tropopause, which explains its relatively higher water vapor concentration. The pattern of dehydration locations is also different among the three reanalyses. ERAi dehydration pattern stretches across the Pacific while CFSR and MERRA concentrate dehydration activity in the West Pacific. CSFR and ERAi also show less dehydration activity in the West Pacific Southern Hemisphere than MERRA. The trajectory models' lower northern high latitude stratosphere tends to be dry because too little methane-derived water descends from the middle stratosphere. Using the MLS tropical tape recorder signal, we find that MERRA vertical ascent is 15% too weak while ERAi is 30% too strong. The trajectory model reproduces the observed reduction in the amplitude of the 100-hPa annual cycle in zonal mean water vapor as it propagates to middle latitudes. Finally, consistent with the observations, the models show less than 0.2 ppm decade?1 trend in water vapor both at mid-latitudes and in the tropics.

  10. Transpiration mass spectrometry of high temperature vapors

    International Nuclear Information System (INIS)

    Material transport via vapor phase species at high temperature and pressure is an important phenomenon in materials science and technology. The preparation of high purity semiconductor and ceramic materials utilizes vapor transport to advantage, whereas the corrosion of power plant boilers, gas turbines and other advanced energy devices results from reactive vapor transport. To understand and control these transport phenomena, it is essential to be able to identify and measure the key chemical species present in the vapor phase systems. However, in the past, classical characterization methods such as transpiration and Knudsen or Langmuir effusion have been limited because they do not establish the molecular identity of transport species or because low pressures are necessary to make effusion measurements. Transpiration Mass Spectrometry (TMS) overcomes both of these limitations by combining the basic features of transpiration and mass spectrometry. With this technique, it is possible to sample reactive gases directly from high-temperature, high ressure atmospheres for qualitative and quantitative characterization with a mass spectrometer. To demonstrate the method, the thermodynamic equilibrium vaporization of the salts Na2SO4 and NaCl was studied at total pressures up to an atmosphere using N2 or Ar as carrier gases

  11. DISTRIBUTION OF WATER VAPOR IN MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    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 AV2O 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 of comparing measured water-vapor column densities with such traditional cloud tracers as 13CO or C18O. These results also support cloud models that incorporate freeze out of molecules as a critical component in determining the depth-dependent abundance of water vapor.

  12. Vapor scavenging by atmospheric aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. The generation and evolution of anisotropic gas-permeability during viscous deformation in conduit-filling ignimbrites

    Science.gov (United States)

    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-permeability of the deposit. Porosity, on the other hand, appears to play a secondary role. This, fabric dependent, anisotropic permeability evolution of fragmental deposits during welding directly affects the gas escape from, and transport through the deposit and, therewith, plays a key role in the gas-pressure distribution and evolution within the volcano.

  14. Seismic restraint means

    International Nuclear Information System (INIS)

    A seismic restraint means for supporting a generally cylindrical nuclear radiation detector within a tubular thimble. At least two housing segments are joined together to form a clamp-like ring about the cylinder. At least one energy absorbing means is operably associated with each segment for generally radial displacement relative thereto. The energy absorbing means are characterized by a damping means therein which is characterized by resiliency and a lack of resonance. The damping means is preferably a knitted metal pad formed from wound, flattened wire-mesh tubing, stainless steel wool, or thin metal strip looped to form a sponge-like material

  15. Water vapor release from biofuel combustion

    Directory of Open Access Journals (Sweden)

    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.

  16. Advanced Atmospheric Water Vapor DIAL Detection System

    Science.gov (United States)

    Refaat, Tamer F.; Elsayed-Ali, Hani E.; DeYoung, Russell J. (Technical Monitor)

    2000-01-01

    Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface. This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto a small Printed Circuit Board (PCB) with minimal weight and power consumption. Comparing its measurements to an existing DIAL system for aerosol and water vapor profiling validated the detection system.

  17. Vapor characterization of Tank 241-C-103

    International Nuclear Information System (INIS)

    The Westinghouse Hanford Company Tank Vapor Issue Resolution Program has developed, in cooperation with Northwest Instrument Systems, Inc., Oak Ridge National Laboratory, Oregon Graduate Institute of Science and Technology, Pacific Northwest Laboratory, and Sandia National Laboratory, the equipment and expertise to characterize gases and vapors in the high-level radioactive waste storage tanks at the Hanford Site in south central Washington State. This capability has been demonstrated by the characterization of the tank 241-C-103 headspace. This tank headspace is the first, and for many reasons is expected to be the most problematic, that will be characterized (Osborne 1992). Results from the most recent and comprehensive sampling event, sample job 7B, are presented for the purpose of providing scientific bases for resolution of vapor issues associated with tank 241-C-103. This report is based on the work of Clauss et al. 1994, Jenkins et al. 1994, Ligotke et al. 1994, Mahon et al. 1994, and Rasmussen and Einfeld 1994. No attempt has been made in this report to evaluate the implications of the data presented, such as the potential impact of headspace gases and vapors to tank farm workers health. That and other issues will be addressed elsewhere. Key to the resolution of worker health issues is the quantitation of compounds of toxicological concern. The Toxicology Review Panel, a panel of Pacific Northwest Laboratory experts in various areas, of toxicology, has chosen 19 previously identified compounds as being of potential toxicological concern. During sample job 7B, the sampling and analytical methodology was validated for this preliminary list of compounds of toxicological concern. Validation was performed according to guidance provided by the Tank Vapor Conference Committee, a group of analytical chemists from academic institutions and national laboratories assembled and commissioned by the Tank Vapor Issue Resolution Program

  18. Smectic-A ordering at a liquid-vapor interface

    Science.gov (United States)

    Mederos, L.; Sullivan, D. E.

    1992-12-01

    The development of smectic-A ordering at the interface between isotropic liquid and vapor is studied using a density-functional theory, based on a mean-field approximation for the effect of attractive pair interactions and weighted-density treatment of repulsive-core contributions. In contrast to earlier microscopic theories of this phenomenon, the bulk liquid and vapor phases are in complete coexistence with each other, and no arbitrary ``surface fields'' independent of molecular pair interactions are invoked. The wetting behavior of the interface is studied as a function of the molecular-core anisotropy, which controls the relative stability of bulk nematic and smectic-A phases, under conditions where the attractive pair interactions favor complete wetting by the nematic phase. There is a change to incomplete wetting by the smectic-A phase when the latter preempts the nematic, in a process analogous to a triple-point wetting transition. This is consistent with experimental results, but the growth of smectic layers at the interface is always found to be continuous, with no evidence of the first-order layering transitions observed in experiment.

  19. Radionuclide transport as vapor through unsaturated fractured rock

    International Nuclear Information System (INIS)

    The objective of this study is to identify and examine potential mechanisms of radionuclide transport as vapor at a high-level radioactive waste repository located in unsaturated fractured rock. Transport mechanisms and processes have been investigated near the repository and at larger distances. Transport mechanisms potentially important at larger distances include ordinary diffusion, viscous flow and free convection. Ordinary diffusion includes self and binary diffusion, Knudsen flow and surface diffusion. Pressure flow and slip flow comprise viscous flow. Free convective flow results from a gas density contrast. Transport mechanisms or processes dominant near the repository include ordinary diffusion, viscous flow plus several mechanisms whose driving forces arise from the non-isothermal, radioactive nature of high-level waste. The additional mechanisms include forced diffusion, aerosol transport, thermal diffusion and thermophoresis. Near a repository vapor transport mechanisms and processes can provide a significant means of transport from a failed canister to the geologic medium from which other processes can transport radionuclides to the accessible environment. These issues are believed to be important factors that must be addressed in the assessment of specific engineering designs and site selection of any proposed HLW repository

  20. Water vapor release from biofuel combustion

    OpenAIRE

    R. S. Parmar; Welling, M.; Andreae, M. O.; Helas, G.

    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 ...

  1. Diode pumped alkali vapor fiber laser

    Science.gov (United States)

    Payne, Stephen A. (Castro Valley, CA); Beach, Raymond J. (Livermore, CA); Dawson, Jay W. (Livermore, CA); Krupke, William F. (Pleasanton, CA)

    2007-10-23

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  2. Electron density measurements in copper vapor lasers

    Science.gov (United States)

    Petrash, Gueorgii G.

    2000-04-01

    A critical overview of the results of electron density measurements in copper vapor lasers is presented. There are considerable contradictions between the results of measurements made by different methods especially between the results concerning temporal behavior of electron density between excitation pulses. Possible reasons of these contradictions are discussed. The method of electron density measurement based on atomic hydrogen Balmer lines broadening is considered in greater detail. Possible nature of the Balmer lines emission under the conditions of copper vapor laser operation and processes of the lines broadening are discussed.

  3. Vapor phase crystallization in Apollo 14 breccia.

    Science.gov (United States)

    Mckay, D. S.; Clanton, U. S.; Morrison, D. A.; Ladle, G. H.

    1972-01-01

    The vugs contained in many of the highly recrystallized breccias from Apollo 14 are discussed, along with the well-developed crystals of plagioclase, pyroxene, ilmenite, apatite, whitlockite, iron, nickel-iron, and troilite that extend from the vug walls and bridge open spaces. These crystals are interpreted as having formed by deposition from a hot vapor containing oxides, halides, sulfides, alkali metals, iron and possibly other chemical species. The hot vapor was associated with the thermal metamorphism and subsequent cooling of the Fra Mauro formation after it had been deposited as an ejecta blanket by the Imbrian impact.

  4. Nonequilibrium vapor generation model for flashing flows

    International Nuclear Information System (INIS)

    A nonequilibrium vapor generation model for flashing flows is presented. The model consists of a flashing inception point, a bubbly flow regime followed by a bubbly-slug regime, an annular or annular-mist regime, and finally a dispersed-droplet regime. Existence of superheated liquid at the inception point and beyond is recognized. The vapor generation rate in each flow regime is calculated from the estimates for interfacial area density and net interfacial heat flux. However, the bubble number density at the flashing inception point was varied to obtain optimum fits with the void fraction data taken in a vertical converging-diverging nozzle. 32 refs

  5. Drag Reduction by Leidenfrost Vapor Layers

    KAUST Repository

    Vakarelski, Ivan U.

    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.

  6. Darwinism and the meaning of ‘meaning

    Directory of Open Access Journals (Sweden)

    Castrodeza, Carlos

    2009-12-01

    Full Text Available The problem of the meaning of life is herewith contemplated from a Darwinian perspective. It is argued how factors such as existential depression, the concern about the meaning of ‘meaning’, the problem of evil, death as the end of our personal identity, happiness as an unachievable goal, etc. may well have an adaptive dimension ‘controlled’ neither by ourselves nor obscure third parties (conspiracy theories but ‘simply’ by our genes (replicators in general so that little if anything is to be done to find a radical remedy for the human condition.

    El problema del sentido de la existencia se contempla en estas páginas desde una perspectiva darwiniana. Se argumenta como factores tales como la depresión existencial, la preocupación acerca del sentido del ‘sentido’, el problema del mal, la muerte como fin de nuestra identidad personal, la felicidad como meta inalcanzable, etc. pueden tener una dimensión adaptativa que no está ‘controlada’ ni por nosotros ni por terceras partes (teorías de la conspiración sino ‘simplemente’ por nuestros genes (replicadores en general de modo que nada o más bien poco se puede hacer para remediar en profundidad la condición humana.

  7. Cable-in-conduit conductors: lessons from the recent past for future developments with low and high temperature superconductors

    Science.gov (United States)

    Muzzi, L.; De Marzi, G.; Di Zenobio, A.; della Corte, A.

    2015-05-01

    We review progress in the design of high field superconducting cable-in-conduit conductors (CICCs) for fusion applications, with special attention to the results of recent key experiments, leading to the state-of-the-art CICC technology: the ITER Toroidal Field and Central Solenoid programs, the EFDA Dipole conductor development program, the NHFML Hybrid Magnet project, the EU-TF Alt conductor demonstration, and the CRPP React & Wind flat cable test. For these projects, the main CICC design driver was the mitigation of Nb3Sn conductor performance degradation with electro-magnetic loading cycles. This was achieved by proper choice of cable layout and of conductor geometry, depending on the specific operating conditions and project requirements. In all cases, the necessity to limit cable movements inside the conductor jacket was identified to be of crucial importance. The main aspects of CICC manufacture are also discussed here, at least for what is the experience gained by the authors in both CICC jacketing and cabling processes. Finally, the state of the art of high-temperature superconducting (HTS) cables is discussed: at present, this technology is still in its infancy, but it is highly likely that major technological improvements could eventually lead to a widespread use of HTS CICCs.

  8. Effect of current imbalance on stability of a cable-in-conduit conductor consisting of chrome-plated strands

    International Nuclear Information System (INIS)

    The effect of an unbalanced current distribution in a conductor consisting of chrome plated strands on stability was investigated using a cable-in-conduit conductor (CICC) consisting of 27 NbTi chrome-plated strands. In addition, the quench behavior when a non-uniform current distribution was produced in the conductor was studied from the experimental results. Moreover, impedance of the chrome-plated strands was measured using the sample conductor. The results show that the stability is determined by the largest strand current when it is sufficiently large otherwise by the transport current when it is not high enough. It was found that it took a long time to make the conductor quench from the onset of the normal transition of the strand carrying the large current. This is explained by the good diffusivity of the coolant temperature in the conductor's cross section. Since the ramp-rate limitation cannot probably take place if the coolant temperature is diffused well in the conductor's cross section, it is expected the ramp-rate limitation can be prevented using this effect. It is also shown that the chrome-plated strands come into contact with one another with uniform transverse conductance on the order of 103 S/m. (author)

  9. Characterization of Alloys with Potential for Application in Cable-in-Conduit Conductors for High-Field Superconducting Magnets

    Science.gov (United States)

    Walsh, R. P.; Miller, J. R.; Toplosky, V. J.

    2004-06-01

    Since the introduction of the cable-in-conduit conductor (CICC) concept, a variety of alloys have been proposed for fabricating the jacket. The jacket provides primary containment of the supercritical helium coolant and is typically also the primary structural component for the magnet. These functions create requirements for strength, toughness, weldability, and fabricability in tubular form. When the CICC uses Nb3Sn, there are additional requirements to accommodate the manufacturing and heat-treatment processes for the superconductor as well as its strain-sensitive performance during operation. Both of the present favorite jacket alloys, Incoloy 908 and modified (ultra-low carbon) 316LN, have both demonstrated acceptable functionality as well as a few undesirable features. In this paper, we present data from cryogenic mechanical tests on a group of heat-resistant, high-strength superalloys that appear to offer equal or better mechanical performance (e.g. strength, toughness, and modulus) while mitigating the undesirable aspects (e.g. SAGBO in the case of I908 and thermal-expansion mismatch with Nb3Sn in the case of 316LN). Data are presented for each alloy in the as-received and aged conditions. These alloys are presently being considered as candidates for use in the next-generation hybrid magnet for the NHMFL but may also be of interest to the fusion and energy storage communities.

  10. Connecting conduit-free and bypass circuit-less mini LVADs eliminate the most likely sites of thrombosis

    Directory of Open Access Journals (Sweden)

    Kun-Xi Qian

    2009-06-01

    Full Text Available All existing left ventricular assist devices (LVADs need inlet and outlet connecting con-duits and the assist pumping blood flows through the bypass circuit from left ventricle to aorta. It will result in some most likely sites of thrombosis and brings about physiological dis-turbance to natural circulation, as well as addi-tional need for anatomic occupation in chest. The author developed a trans-apical and cross-valvular intra-ventricular axial pump and an aortic valvo- pump to solve these problems. The intra-ventricular pump weighing 53g has a length of 115mm and its largest O.D. is 13mm. The motor is 60mm long and the pump 55mm. In both sides of motor, specially designed needle bearings are devised and a purge system keeps the motor together with bearings working in sa-line. The device is inserted into the ventricle by trans-apex and then into the aorta by cross-valve. It is used for recovery therapy or bridge to transplantation. The bearing-less valvo-pumps have an outer diameter of 21mm, 23mm or 25mm for patients with different body weights. The weight of the devices is 27g, 31g or 40g respectively. Used for destination therapy it can be easily sewed onto the aortic valve annu-lus, delivers blood from ventricle to aorta di-rectly. These two novel mini LVADs may reduce thrombosis risk in clinical applications.

  11. Performance of cable-in-conduit conductors in ITER [International Thermonuclear Experimental Reactor] toroidal field coils with varying heat loads

    International Nuclear Information System (INIS)

    The toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) will operate with varying heat loads generated by ac losses and nuclear heating. The total heat load is estimated to be 2 kW per TF coil under normal operation and can be higher for different operating scenarios. Ac losses are caused by ramping the poloidal field (PF) for plasma initiation, burn, and shutdown; nuclear heating results from neutrons that penetrate into the coil past the shield. Present methods to reduce or eliminate these losses lead to larger and more expensive machines, which are unacceptable with today's budget constraints. A suitable solution is to design superconductors that operate with high heat loads. The cable-in-conduit conductor (CICC) can operate with high heat loads. One CICC design is analyzed for its thermal performance using two computer codes developed at LLNL. One code calculates the steady state flow conditions along the flow path, while the other calculates the transient conditions in the flow. We have used these codes to analyze the superconductor performance during the burn phase of the ITER plasma. The results of these analyses give insight to the choice of flow rate on superconductor performance. 4 refs., 5 figs

  12. Two-stage multi-Gaussian fitting of conduit artery photoplethysmography waveform during induced unilateral hemodynamic events

    Science.gov (United States)

    Grabovskis, Andris; Marcinkevics, Zbignevs; Rubins, Uldis; Aivars, Juris Imants

    2015-03-01

    Photoplethysmography (PPG) is an optical technique with high diagnostic potential, yet clinical applications remain underdeveloped. Standardization of signal recording and quantification of waveform are essential prerequisites for broader clinical use. The aim of this study was to utilize a two-stage multi-Gaussian fitting technique in order to examine the parameters of conduit artery PPG waveform recorded during increasing the unilateral regional vascular resistance (RVR). This study was conducted on 14 young and healthy volunteers; various external compressions (ECs) were performed by inflating a tight cuff at 0, 40, 80, and 200 mmHg, while registering femoral PPG (wavelength 880 nm), diameter, blood flow linear velocity (vascular ultrasound), and the arterial pressure (Finapres) during the states of the baseline, partial, and total arterial occlusion, and resultant reactive hyperemia. An increase of the EC elevated the arterial stiffness (AS) and the unilateral distal RVR, and caused a shift of the fitted multi-Gaussian parameters: a decreased delay between reflected and traverse wave components and an increased ratio of their amplitudes. It was concluded that two-stage multi-Gaussian waveform quantification demonstrates an approach potentially extending the use of arterial site PPG in the assessment of diagnostically useful markers e.g., the RVR and the AS.

  13. Major eruptive style changes induced by structural modifications of a shallow conduit system: the 2007-2012 Stromboli case

    Science.gov (United States)

    Calvari, S.; Bonaccorso, A.; Madonia, P.; Neri, M.; Liuzzo, M.; Salerno, G. G.; Behncke, B.; Caltabiano, T.; Cristaldi, A.; Giuffrida, G.; La Spina, A.; Marotta, E.; Ricci, T.; Spampinato, L.

    2014-07-01

    Stromboli is known for its mild, persistent explosive activity from the vents located within the summit crater depression at the uppermost part of the Sciara del Fuoco (SdF) depression. Effusive activity (lava flows) at this volcano normally occurs every 5-15 years, involving often the opening of eruptive fissures along the SdF, and more rarely overflows from the summit crater. Between the end of the 2007 effusive eruption and December 2012, the number of lava flows inside and outside the crater depression has increased significantly, reaching a total of 28, with an average of 4.8 episodes per year. An open question is why this activity has become so frequent during the last 6 years and was quite rare before. In this paper, we describe this exceptional activity and propose an interpretation based on the structural state of the volcano, changed after the 2002-2003 and even more after the 2007 flank effusive eruption. We use images from the Stromboli fixed cameras network, as well as ground photos, plume SO2 and CO2 fluxes released by the summit crater, and continuous fumarole temperature recording, to unravel the interplay between magma supply, structural and morphology changes, and lava flow output. Our results might help forecast the future behaviour and hazard at Stromboli and might be applicable to other open-conduit volcanoes.

  14. Minimizing coupling loss by selection of twist pitch lengths in multi-stage cable-in-conduit conductors

    Science.gov (United States)

    Rolando, G.; Devred, A.; Nijhuis, A.

    2014-01-01

    The numerical code JackPot-ACDC (van Lanen et al 2010 Cryogenics 50 139-48, van Lanen et al 2011 IEEE Trans. Appl. Supercond. 21 1926-9, van Lanen et al 2012 Supercond. Sci. Technol. 25 025012) allows fast parametric studies of the electro-magnetic performance of cable-in-conduit conductors (CICCs). In this paper the code is applied to the analysis of the relation between twist pitch length sequence and coupling loss in multi-stage ITER-type CICCs. The code shows that in the analysed conductors the coupling loss is at its minimum when the twist pitches of the successive cabling stages have a length ratio close to one. It is also predicted that by careful selection of the stage-to-stage twist pitch ratio, CICCs cabled according to long twist schemes in the initial stages can achieve lower coupling loss than conductors with shorter pitches. The result is validated by AC loss measurements performed on prototype conductors for the ITER Central Solenoid featuring different twist pitch sequences.

  15. 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.

    Directory of Open Access Journals (Sweden)

    João G Franca

    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.

  16. A Comparative Study of Fast-Track Verus Conventional Surgery in Patients Undergoing Laparoscopic Radical Cystectomy and Ileal Conduit Diversion: Chinese Experience

    OpenAIRE

    Guan, Xiao; Liu, Longfei; Lei, Xiang; ZU, XIONGBING; Yuan LI; Chen, Mingfen; Long WANG; Qi, Lin

    2014-01-01

    Fast-track surgery (FTS), which combines various techniques with evidence-based adjustments, is aimed to reduce postoperative morbidity, attenuate surgical stress response, thereby accelerating recovery and shorting length of stay. To further investigate the effectiveness of fast-track surgery, we compared the short-term outcomes of laparoscopic radical cystectomy and ileal conduit diversion for Chinese bladder cancer patients with FTS or with CS in our hospital. Patients with bladder cancer ...

  17. 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

    Science.gov (United States)

    Oliveira, Julia T.; Bittencourt-Navarrete, Ruben Ernesto; de Almeida, Fernanda M.; Tonda-Turo, Chiara; Martinez, Ana Maria B.; Franca, João G.

    2014-01-01

    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 three 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 five 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. PMID:25360086

  18. The search for valved conduit tissue grafts for adults (>22 mm): an ultrasonographic study of jugular vein diameters of horses and cattle

    OpenAIRE

    Jenni Rolf; Schwarzwald Colin C

    2009-01-01

    Abstract Background Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm. Methods The stu...

  19. The search for valved conduit tissue grafts for adults (>22 mm): an ultrasonographic study of jugular vein diameters of horses and cattle

    OpenAIRE

    Schwarzwald, C C; JENNI, R.

    2009-01-01

    BACKGROUND: Natural heterologous valved conduits with a diameter greater than 22 mm that can be used for right ventricular outflow tract reconstruction in adults are not commercially available. The purpose of this study was to measure by ultrasonography the maximum diameter of the distended jugular veins of horses and cattle, respectively, to identify a population of animals that would be suitable for post-mortem collection of jugular veins at sizes greater than 22 mm. METHODS: The study popu...

  20. A Local Propagation for Vapor Explosions

    International Nuclear Information System (INIS)

    Explosive boiling, defined as energy transfer leading to formation of vapor rapidly enough to produce large shock waves, has been widely studied in a number of contexts. Depending upon the nature and temperatures of the liquids and mode of contacting, large-scale mixing and explosive vaporization may occur, or alternatively, only relatively non-energetic, film-type boiling may exist. The key difference is whether a mechanism is operative for increasing the liquid-liquid interfacial area in a time scale consistent with the formation of a detonation wave. Small drops of a cold volatile liquid were dropped onto a free surface of a hot, non-volatile liquid. The critical Weber number for coalescence is obtained from the envelope of the film boiling region. Markedly different behavior for the two hot liquids is observed. A 'splash' theory for local propagation of vapor explosions in spontaneously nucleating liquid-liquid systems is now formulated. After a random contact is made, explosive growth and coalescence of the vapor bubbles occurs as soon as the surrounding pressure is relieved, resulting in a high-pressure vapor layer at the liquid-liquid contact area. This amounts to an impact pressure applied to the free surface, with a resulting velocity distribution obtained from potential flow theory. The peak pressure predictions are. consistent with data for Freon-oil mixing, but further evaluation will await additional experimental data. Nevertheless, the current inference is that a UO2 -Na vapor explosion in a reactor environment cannot be visualized. In conclusion: The propagation model presented here differs in some details from that of Henry and Fauske, although both are consistent with some peak pressure data obtained by Henry, et al. Clearly, additional experimental information is needed for further evaluation of these theories. Nevertheless, it should be emphasized that even at this time a number of important observations concerning the requirements for a vapor explosion can be made. Both theories postulate that spontaneous nucleation is a necessary requirement for vapor explosions. In the case of Freon-oil, which can be considered to be a 'well-wetted' system, this implies homogeneous nucleation. For metal-water systems, however, vapor-free heterogeneous nucleation may take place, in view of the unique surface properties of water. Indeed, for aqueous systems it is difficult to suppress very small pre-existing surface nuclei. The practical effect, however, is the same in that nucleation may occur in metal-water systems at liquid-liquid interfacial temperatures somewhat below the homogeneous nucleation temperature of water, but with comparable time scales and vapor pressures. Another important requirement common to both the splash and capture theories, as well as the Freon-oil data, is the necessity for film boiling to occur when the two liquids are initially mixed. This requirement is not satisfied by the sodium-UO2 system, based on the Henry film bailing correlation. Rapid breakup therefore occurs as the two liquids are mixed, preventing a highly energetic interaction. Our current assessment, therefore, is that a sodium-UO2 vapor explosion in a reactor environment is extremely unlikely

  1. Effectiveness of air vapor barriers combined with ventilated crawlspaces in decreasing residential exposure to radon daughters to radon daughters: preliminary report

    International Nuclear Information System (INIS)

    Radon gas is present in many homes. Concentrations may be increased in airtight, energy-efficient structures. This is especially true in cold climates where energy conservation is an important factor leading to the widespread application of sealing and tightening techniques both in older renovated homes and new construction. To reduce radon concentrations, it may be effective to ventilate crawlspaces and prevent infiltration of radon gas into the house by means of an air/vapor barrier. The authors report first results of comparing radon levels in homes with and without ventilated crawlspaces and air/vapor barriers. Radon emissions were measured in a tightly sealed home with ventilated crawlspaces and an air/vapor barrier and in two homes without such vapor barriers and ventilated crawlspaces, but differing in ventilation. Preliminary results suggest that use of ventilated crawlspaces and bottomside vapor barriers may reduce indoor radon levels by approximately 60%. 15 references, 1 table

  2. Transitions between fall phases and pyroclastic density currents during the AD 79 eruption at Vesuvius: building a transient conduit model from the textural and volatile record

    Science.gov (United States)

    Shea, Thomas; Gurioli, Lucia; Houghton, Bruce F.

    2012-12-01

    The magmatic phase of the AD 79 eruption of Vesuvius produced alternations of fall and pyroclastic density current (PDC) deposits. A previous investigation demonstrated that the formation of several PDCs was linked with abrupt increases in the proportion of denser juvenile clasts within the eruptive column. Under the premise that juvenile clast density is controlled by vesiculation processes within the conduit, we investigate the processes responsible for these variations at or close to fragmentation levels. Pumice textures (vesicle sizes, numbers, and connectivity combined with crystal textures) from the AD 79 PDC deposits are compared to those from interbedded fall samples. Both PDC and fall deposits preserve textures that represent a full spectrum of degassing and outgassing processes, from bubble nucleation to collapse. Combining the textural and volatile (groundmass H2O) data, we derive a conduit model that satisfies all the textural and physical observations made for this phase of the eruption: lateral vesicularity/density stratifications are produced by maturing of bubble textures with superimposed localized shearing of bubble-rich magmas, which enhance outgassing of H2O. The incorporation of denser slower-moving magma from the conduit margins ("lateral magma density gradient") is likely to be responsible for the higher abundances of dense juvenile pumice that triggered partial column collapses. We also illustrate how variations in the fragmentation depth (tapping a "vertical magma density gradient") can be responsible for variations in erupted clast density distributions, and potentially in the extent of degassing/outgassing.

  3. Absolute gravity change associated with magma mass movement in the conduit of Asama Volcano (Central Japan), revealed by physical modeling of hydrological gravity disturbances

    Science.gov (United States)

    Kazama, Takahito; Okubo, Shuhei; Sugano, Takayuki; Matsumoto, Shigeo; Sun, Wenke; Tanaka, Yoshiyuki; Koyama, Etsuro

    2015-02-01

    The gravity signal originating from magma mass movement in a volcanic conduit is retrieved from the hydrologically disturbed absolute gravity data obtained at Asama Volcano (Central Japan) in 2004, using a three-dimensional hydrological model. We improve the hydrological model of the previous study using realistic soil parameters and boundary conditions, to better estimate the spatiotemporal land-water distributions and the consequent hydrological gravity disturbances. The newly estimated gravity disturbances agree with the absolute gravity values observed by FG5 gravimeters in 2004-2009 within about 2.6 ?Gal, by additionally accounting for the excess discharge of groundwater mass associated with a sloping impermeable surface below the discharge area. After the gravity disturbance of 20 ?Gal amplitude is subtracted from the absolute gravity data observed during the 2004 eruptive event, the gravity residual of 5 ?Gal amplitude shows a significant decrease in synchronization with eruptions, because the ascending magma mass in the conduit affects the upward attraction force to the gravimeters installed on the flank of Asama Volcano. The magma head altitude, to which the residual gravity is converted assuming a homogeneous linear density in the conduit, shows a comprehensive agreement of the time variation in the magma head with those in other volcanic observations, such as gas emission rate and earthquake frequency. By correcting the hydrological gravity disturbances using this hydrological model and simultaneously obtained meteorological data in real time, spatiotemporal variations in the magma mass can be instantaneously monitored at Asama Volcano, even before eruptions during future volcanic events.

  4. Tapping the Potential of Skill Integration as a Conduit for Communicative Language Teaching

    Directory of Open Access Journals (Sweden)

    Shu-hua Wu

    2014-10-01

    Full Text Available The purpose of this classroom-based study was to discover the kinds of skill integration tasks that were employed by English teachers in Kuwait and to measure their attitudes toward implementing the skill integration technique in their classrooms. Data collection involved recording 25 hours of classroom-based observations, conducting interviews with the same group of teachers, and distributing a survey to further explore the teachers’ attitudes toward the skill integration technique. Data analysis involved categorizing skill integration tasks, analyzing the interview data, and counting the means and standard deviations of the survey data. Findings indicated that the participating teachers performed a wide range of transactional and interactional tasks that involved the simultaneous integration of speaking, listening, reading, and writing in their classrooms. The findings also revealed that even though the skill integration technique was adopted by most of the English teachers, they were ambivalent toward its implementation in their classrooms. This was partly due to the negative washback effect of traditional English tests that measure students’ accurate application of grammar rules but not their fluency and ability to use the L2 as a tool for communication. Implications for L2 pedagogy were drawn regarding the need for teachers to expose students of all proficiency levels to both transactional and interactional tasks in the classroom. To counter the negative washback effect of conventional discrete-point tests, English teachers were encouraged to develop communicative tests that involve skill integration and emphasize the development of the four language skills in their daily classroom activities.

  5. Mean-Field Networks

    OpenAIRE

    Li, Yujia; Zemel, Richard

    2014-01-01

    The mean field algorithm is a widely used approximate inference algorithm for graphical models whose exact inference is intractable. In each iteration of mean field, the approximate marginals for each variable are updated by getting information from the neighbors. This process can be equivalently converted into a feedforward network, with each layer representing one iteration of mean field and with tied weights on all layers. This conversion enables a few natural extensions,...

  6. Scalable K-Means++

    OpenAIRE

    Bahmani, Bahman; Moseley, Benjamin; 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...

  7. Waste tank headspace gas and vapor characterization reference guide

    International Nuclear Information System (INIS)

    This document is to serve as a reference guide for gas and vapor sample results presented in tank characterization reports. It describes sampling equipment, devices, and protocols, and sample collection and analysis methods common to all vapor samples

  8. 33 CFR 157.132 - Cargo tanks: Hydrocarbon vapor emissions.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Cargo tanks: Hydrocarbon vapor emissions...ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN...Washing (COW) System on Tank Vessels Design, Equipment...Installation § 157.132 Cargo tanks: Hydrocarbon vapor...

  9. Application of laser Doppler velocimeter to chemical vapor laser system

    Science.gov (United States)

    Gartrell, Luther R.; Hunter, William W., Jr.; Lee, Ja H.; Fletcher, Mark T.; Tabibi, Bagher M.

    1993-01-01

    A laser Doppler velocimeter (LDV) system was used to measure iodide vapor flow fields inside two different-sized tubes. Typical velocity profiles across the laser tubes were obtained with an estimated +/-1 percent bias and +/-0.3 to 0.5 percent random uncertainty in the mean values and +/-2.5 percent random uncertainty in the turbulence-intensity values. Centerline velocities and turbulence intensities for various longitudinal locations ranged from 13 to 17.5 m/sec and 6 to 20 percent, respectively. In view of these findings, the effects of turbulence should be considered for flow field modeling. The LDV system provided calibration data for pressure and mass flow systems used routinely to monitor the research laser gas flow velocity.

  10. Kinetics of chemical vapor deposition of boron on molybdenum

    International Nuclear Information System (INIS)

    Experimental rate data of chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed to determine the reaction mechanism. The experiments were conducted at atmospheric pressure. The weight change of the sample was noted by means of a thermobalance. Molybdenum was used as the substrate. It has been found that the outer layer of the deposited film is Mo/sub 2/B/sub 5/ and the inner layer is MoB, and in the stational state of the reaction, the diffusion in the solid state is considered not to be rate controlling. When mass transport limitation was absent, the reaction orders with respect to boron trichloride and hydrogen were one third and one half, respectively. By comparing these orders with those obtained from Langmuir-Hinshelwood type equations, the rate controlling mechanism is identified to be the desorption of hydrogen chloride from the substrate

  11. Q Conversion Factor Models for Estimating Precipitable Water Vapor for Turkey

    Science.gov (United States)

    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 precipitable water vapor is the conversion factor Q which is shown in Emardson and Derks' studies and also Jade and Vijayan's. Developing a regional model using either Tm-Ts equation or the conversion factor Q will provide a basis for GNSS Meteorology in Turkey which depends on the analysis of the radiosonde profile data. For this purpose, the radiosonde profiles from Istanbul, Ankara, Diyarbaki r, Samsun, Erzurum, Izmir, Isparta and Adana stations are analyzed with the radiosonde analysis algorithm in the context of the 'The Estimation of Atmospheric Water Vapour with GPS' Project which is funded by the Scientific and Technological Research Council of Turkey (TUBITAK). The Project is also in the COST Action ES1206: Advanced Global Navigation Satellite Systems tropospheric products for monitoring severe weather events and climate (GNSS4SWEC). In this study, regional models using the conversion factor Q are used for the determination of precipitable water vapor, and applied to the GNSS derived wet tropospheric zenith delays. Henceforth, the estimated precipitable water vapor and the precipitable water vapor obtained from the radiosonde station are compared. The average of the differences between RS and models for Istanbul and Ankara stations are obtained as 2.0±1.6 mm, 1.6±1.6 mm, respectively.

  12. Multicomponent droplet vaporization in a convecting environment

    International Nuclear Information System (INIS)

    In this paper a parametric study of the fundamental exchange processes for energy, mass and momentum between the liquid and gas phases of multicomponent liquid vaporizing droplets is presented. The model, which examines an isolated, vaporizing, multicomponent droplet in an axisymmetric, convecting environment, considers the different volatilities of the liquid components, the alteration of the liquid-phase properties due to the spatial/temporal variations of the species concentrations and also the effects of multicomponent diffusion. In addition, the model accounts for variable thermophysical properties, surface blowing and droplet surface regression due to vaporization, transient droplet heating with internal liquid circulation, and finally droplet deceleration with respect to the free flow due to drag. The numerical calculation employs finite-difference techniques and an iterative solution procedure that provides time-varying spatially-resolved data for both phases. The effects of initial droplet composition, ambient temperature, initial Reynolds number (based on droplet diameter), and volatility differential between the two liquid components are investigated for a liquid droplet consisting of two components with very different volatilities. It is found that mixtures with higher concentration of the less volatile substance actually vaporize faster on account of intrinsically higher liquid heating rates

  13. Sampling systems for vapor and trace detection

    Science.gov (United States)

    Sheldon, Timothy G.; Lacey, Richard J.; Smith, G. M.; Moore, Peter; Head, Lynne

    1994-03-01

    This paper discusses the various methods of acquiring usable samples for analysis by a number of explosives vapor and trace detectors or `sniffers', and describes a system under development at PSDB which, we believe, could enhance the performance of many of these systems.

  14. Optical Multidimensional Spectroscopy of Atomic Vapor

    Directory of Open Access Journals (Sweden)

    Siemens Mark E.

    2013-03-01

    Full Text Available Optical single- and double-quantum three-dimensional Fourier-transform spectra are obtained for atomic vapors. We show that three-dimensional spectra can be used to identify the Hamiltonian of complex systems and to reveal the nature of many-body interactions.

  15. Optical Multidimensional Spectroscopy of Atomic Vapor

    OpenAIRE

    Siemens Mark E.; Moody Galan; Bristow Alan D.; Li Hebin; Cundiff Steven T.

    2013-01-01

    Optical single- and double-quantum three-dimensional Fourier-transform spectra are obtained for atomic vapors. We show that three-dimensional spectra can be used to identify the Hamiltonian of complex systems and to reveal the nature of many-body interactions.

  16. Energy pooling collisions in pure cadmium vapors

    International Nuclear Information System (INIS)

    We have investigated energy pooling processes in pure Cadmium vapors excited by a pulsed laser beam resonant with the Cd(51S0)?Cd(53P1) intercombination transition. Starting from the measured fluorescence intensities, we have determined the cross sections for the processes populating the 53Dj levels using a rate equation system and accounting for the radiation trapping phenomenon

  17. Atomic-vapor-laser isotope separation

    International Nuclear Information System (INIS)

    This paper gives a brief history of the scientific considerations leading to the development of laser isotope separation (LIS) processes. The close relationship of LIS to the broader field of laser-induced chemical processes is evaluated in terms of physical criteria to achieve an efficient production process. Atomic-vapor LIS processes under development at Livermore are reviwed. 8 figures

  18. Vaporization of synthetic fuels. Final report. [Thesis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Estimation method of stability under current re-distribution between strands for the cable-in conduit conductor; Denryu saihaibun wo tomonau CIC gata chodendo nensen dotai no anteisei hyokaho

    Energy Technology Data Exchange (ETDEWEB)

    Ono, M.; Hamajima, T.; Yamaguchi, M.; Fujioka, T. [Toshiba Corp. (Japan). Heavy Apparatus Engineering Lab.; Sawada, Y. [Kogakuin Univ., Tokyo (Japan); Sawa, K. [Keio Univ., Yokohama (Japan). Faculty of Science and Technology

    1996-10-25

    Cable-in-conduit conductors (ClCCs), composed of multi-strand superconducting cables cooled with supercritical helium, are essential to superconducting magnets that require large current capacities, low AC losses and high rigidity for fusion machines. A conductor cabled by several hundreds of superconducting strands with superficial chrome plating, oxide or CuNi result in the problem of unbalanced current distribution among the strands. The minimum quench energy (MQE) of ClC multi-strand cables under unbalanced current distribution is greatly affected by the electrical resistance among the strands. This means that the stability is influenced by the current-shearing process among strands. A higher margin of stability is induced by increasing current sharing and more rapid current transfer to the neighboring strands rather than thermal diffusion to helium. The most suitable parameter to govern this process is the impedance between strands. A simplified electrical circuit model simulating the current-sharing process among strands was proposed to estimate stability. 11 refs., 11 figs., 1 tab.

  20. A heated vapor cell unit for DAVLL in atomic rubidium

    OpenAIRE

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

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 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...

  1. Particle/vapor concentrations and distributions of PAHs in the atmosphere of southern Chesapeake Bay

    International Nuclear Information System (INIS)

    Atmospheric PAH concentrations were measured at four sites characterized as rural (Haven Beach), semiurban (York River), urban (Hampton), and industrialized (Elizabeth River) areas as part of a study to quantify gaseous exchange fluxes across the air-water interface of southern Chesapeake Bay. Aerosol particle-associated PAH concentrations were similar at all sites; however, PAH vapor concentrations in the urban areas were as much as a factor of 50 greater than those at the rural site. Mean total PAH concentrations ranged from 7.87 ng/m3 at the rural site to 92.8 ng/m3 at the urban site. Daily total PAH concentrations ranged from 1.60 to 198 ng/m3. Exponential increases in PAH vapor concentrations with temperature were observed at the non-rural sites, suggesting volatilization from contaminated surfaces during warmer weather; whereas PAH vapor concentrations at the rural Haven Beach site exhibited little seasonal variability. Aerosol particle-associated PAH levels were similar at all sites and increased in winter due to the temperature dependence of vapor-particle partitioning, increased sources from combustion of fossil fuel and wood for home heating, and cold condensation of source vapors to background aerosols as air masses are dispersed to remote regions. Plots of log Kd vs. log Psat,SC1 indicate PAH partitioning is not at equilibrium in rural areas of Southern Chesapeake Bay. In addition, plots of log Kdake Bay. In addition, plots of log Kd vs. 1/T for individual PAHs indicate difference particle characteristics or partitioning processes influence particle/vapor distributions at the urban and rural sites

  2. Imaging density distribution of a big object by muography and its application to the analysis of gas-liquid two-phase flow in a conduit during volcanic eruption

    International Nuclear Information System (INIS)

    This paper reviews the principle of cosmic-ray muon radiography (muography) and its application to the analysis of gas-liquid two-phase flow in a conduit during volcanic eruption. Muography is a useful technique for imaging internal density distribution of a big object (e.g., a volcano, a blast furnace, etc.). By measuring muon path lengths and absorption along different paths through the object, one can deduce average density along the path inside the object. According to numerical modeling of gas-liquid two-phase flow in the volcanic conduit during a dome-forming eruption, magma porosity (i.e., density) inside the conduit largely changes depending on magma flux even if the porosity at the surface is kept low. The increase in the porosity inside the conduit may induce the transition to explosive eruption. This implies that high-resolution measurement of the porosity distribution inside the conduit is essential for predicting the transition of eruption styles. Recent progress in a muon detector system enables us to perform this measurement, such as in Mt. Iwodake of Satsuma-Iwojima Volcano, Japan. Spatial resolution of muography is adequate for detecting the variation of the porosity inside the conduit. Applications to industrial plant monitoring are also discussed. (author)

  3. New Apparatus for Study of Vapor in Polymeric Membrane during Vapor Permeation.

    Czech Academy of Sciences Publication Activity Database

    Petri?kovi?, Roman; Setni?ková, Kate?ina; Uchytil, Petr

    Taipei : -, 2007, s. 81-82. [Conference of Asenian Membrane Society and 7th Conference on Membrane Science & Technology in Taiwan /4./. Taipei (TW), 16.08.2007-18.08.2007] R&D Projects: GA AV ?R(CZ) IAA4072402 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapor transport study * polymetic membrane * vapor permeation Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  4. Vapor-modulated heat pipe for improved temperature control

    Science.gov (United States)

    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.

  5. Membrane-assisted vapor stripping: energy efficient hybrid distillation-vapor permeation process for alcohol-water separation

    Science.gov (United States)

    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. The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

    International Nuclear Information System (INIS)

    Highlights: • The vaporization enthalpy of (d)-methamphetamine was measured. • The vapor pressure of (d)-methamphetamine as a function of temperature was evaluated. • The vapor pressure of 4-benzylpiperidine as a function of temperature was evaluated. - Abstract: The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7 ± 4.3) kJ · mol?1 and a vapor pressure, p = (38 ± 9) Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T = 298.15 K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8 K or less

  7. Differential absorption lidar measurements of atmospheric water vapor using a pseudonoise code modulated AlGaAs laser. Thesis

    Science.gov (United States)

    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.

  8. Correction technique for Raman water vapor lidar signal-dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    Directory of Open Access Journals (Sweden)

    D. N. Whiteman

    2012-11-01

    Full Text Available The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT and lower stratospheric (LS water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC (Network for the Detection of Atmospheric Composition Change and elsewhere, despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  9. Correction technique for Raman water vapor lidar signal-dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    Science.gov (United States)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L.; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; Jordan, A.; Vömel, H.

    2012-11-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC (Network for the Detection of Atmospheric Composition Change) and elsewhere, despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  10. Interaction of an intense proton beam with a supersonic jet of magnesium vapor (experimental)

    International Nuclear Information System (INIS)

    Experiments are reported on the interaction of a pulsed proton beam with a power up to 1.5 MW with a supersonic jet charge-exchange target of magnesium vapor. The results demonstrate the existence of a critical beam power, --1 MW, above which the charge-exchange properties of the target and the directionality of the supersonic jet are sharply degraded. The experimental results are explained by means of a model of the development of an ionization avalanche in the target

  11. The thermal detonation theory in comparison with large scale vapor explosion experiments

    International Nuclear Information System (INIS)

    By means of both, a transient and a steady state thermal detonation model, simulations of selected large scale (melt mass ? 5 kg) vapor explosion experiments are performed. A detailed model on hydrodynamic fragmentation is used for the energy source term in both models, assuring thus the best-estimate character of this key part of the modeling. After validation of the global modeling, the models may be applied for extrapolations to reactor conditions

  12. Kinetics of the excitation of copper-vapor laser working levels in the twin pulse regime

    Energy Technology Data Exchange (ETDEWEB)

    Isaev, A.A.; Mikhkel' soo, V.T.; Petrash, G.G.; Peet, V.E.; Ponomarev, I.V.

    1988-12-01

    The kinetics of the excitation of copper-vapor laser working levels in the twin pulse regime is studied experimentally. The populations of the resonance and metastable levels are measured by means of resonant absorption of the active medium of the radiation of the pulsed dye laser. It is shown that the parameters of the laser action in the second pulse under delay shortening are limited by the prepulse population of the metastable level. 12 references.

  13. Development of a miniature vapor compression refrigeration system for electronic cooling

    OpenAIRE

    Davies, GF; Eames, IW; Bailey, PB; Dadd, MW; Janiszewski, A; Stone, CR; Maidment, GG; Agnew, B.

    2010-01-01

    Computer chips have generally been cooled by means of a heat sink/fan device; however, such systems are now approaching their limits and in future alternative techniques/devices will be needed. A 3-year project, involving collaboration between groups at three UK universities, is being undertaken to develop a miniature refrigeration device for the cooling of future microprocessors and electronic systems. Using conventional vapor compression refrigeration technology for the cooling of small com...

  14. Method and apparatus for isotope - selectively exciting gaseous or vaporous uranium hexafluoride molecules

    International Nuclear Information System (INIS)

    A method is claimed of isotope-selectively exciting gaseous or vaporous uranium hexafluoride molecules by means of a monochromatic iodine laser beam. The beam frequency is tuned to an absorption band of the molecules to be excited. The iodine laser beam is scattered in liquid and/or solid nitrogen and the beam produced by triply stimulated Raman-scattering is brought into interaction with the uranium hexafluoride molecules

  15. Growth of single crystals by vapor transport in zero-gravity environment, ground-based experiments

    Science.gov (United States)

    Wiedemeier, H.

    1978-01-01

    Mass and heat transfer phenomena associated with the growth of single crystals by chemical vapor transport reactions were investigated. In this technique, a gaseous transport agent reacts with the solid source material to form exclusively gaseous products. The gas phase species migrate from the source to the condensation zone of the closed reaction ampoule where the reverse reaction occurs with formation of single crystals. The necessary concentration gradient is achieved by means of a temperature gradient.

  16. Synthesis of Carbon Nano Tubes on Silicon Substrates Using Alcohol Catalytic Chemical Vapor Deposition

    OpenAIRE

    Mohammad Abu-Abdeen; Abdu Aljaafari

    2011-01-01

    The technique used for synthesizing large quantity carbon nanotubes (CNTs) directly on the surface of silicon substrates has been developed by means of the alcohol catalyst chemical vapor deposition ACCVD method using ethanol. The proposed method adopts an easy and costless liquid-based dip-coat approach for mounting the catalytic metals on the substrates. Reasonable quality formation of catalyst preparation was found at 5 min of dipping the substrate into cobalt acetate solution and withdraw...

  17. The Response of Stratospheric Water Vapor to a Changing Climate: Insights from In Situ Water Vapor Measurements

    OpenAIRE

    Sargent, Maryann Racine

    2012-01-01

    Stratospheric water vapor plays an important role in the Earth system, both through its role in stratospheric ozone destruction and as a greenhouse gas contributing to radiative forcing of the climate. Highly accurate water vapor measurements are critical to understanding how stratospheric water vapor concentrations will respond to a changing climate. However, the past disagreement among water vapor instruments on the order of 1 – 2 ppmv hinders understanding of the mechanisms which control...

  18. Scalable K-Means++

    CERN Document Server

    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...

  19. The dynamics of ice clouds in the TTL as inferred from the isotopic composition of water vapor.

    Science.gov (United States)

    Bolot, M.; Moyer, E. J.; Legras, B.

    2014-12-01

    We show that the profile of the isotopic composition of water vapor can be used to quantify the contribution of deep convection to water vapor in the UT/LS region. The contribution of UT/LS cirrus to radiation balance means that the control of moisture to the TTL is of particular importance. The various processes affecting UT/LS water include convective sources of water (injection of convective ice and subsaturated convective air), dehydration via in situ cirrus formation and sedimentation, and moistening from mixing with extratropical air, but none have been quantified with certainty. We show that these processes can be combined into a one-dimensional advection-dilution model for the isotopic ratio of TTL water vapor, with sources and sinks due to convective moistening and in situ cirrus formation, most of whose parameters can be described from observations and reanalysis. This model can then be fit to an averaged tropical profile of water vapor isotopic ratio in the TTL. The result allows us to back out the convective contribution to UT/LS water vapor. That water vapor contributes directly to in-situ cirrus formation because any injection of water vapor into the subsaturated UT/LS must subsequently be removed by in-situ dehydration. Using isotopic profiles from the ACE-FTS solar-occultation instrument and assuming timescales for evaporation and removal by sedimentation, we demonstrate that convective injection of water vapor significantly increases the production of in-situ cirrus over expectations from large-scale uplift alone. We also show that the turnaround point of UT/LS isotopic profiles - the altitude where isotopic composition begins to increase with height - is readily explained as reflecting the bulk isotopic composition in overshooting convection.

  20. The 2006 Eruption of Raoul Volcano (Kermadecs): A Phreato-magmatic Event From a Hydrothermally-Sealed Volcanic Conduit System.

    Science.gov (United States)

    Christenson, B. W.; Reyes, A. G.; Werner, C. A.

    2006-12-01

    The March 17, 2006 eruption from Raoul volcano (Kermadec Islands, NZ), which tragically claimed the life of NZ Department of Conservation staff member Mark Kearney, is being interpreted as a magmatic-hydrothermal event triggered by shaking associated with regional earthquake swarm activity. Although the eruption released ca. 200 T of SO2, thus confirming its magmatic nature, it occurred without significant precursory volcanic seismicity, and without any of the precursory responses of the volcanic hydrothermal system which were observed prior to the last eruption in 1964. Raoul Island has a long and varied eruption history dating back > 1.4 ma, and has been hydrothermally active throughout historic time. Present day fumarolic and hotspring discharges within Raoul caldera point to the existence of a small but well established, mixed meteoric - seawater hydrothermal system within the volcano. Magmatic signatures are apparent in fumarolic gas discharges, but are heavily masked by their interaction with hydrothermal system fluids (eg. near complete scrubbing of sulphur and halogen gases from the boiling point fumarolic discharges). A diffuse degassing study conducted in 2004 revealed that ca. 80 T/d CO2 is passively discharged from the volcano, suggesting that ongoing (albeit low level) convective degassing of magma occurs at depth. Interestingly, vent locations from the 2006 eruption correspond to areas of relatively low CO2 discharge on the crater floor in 2004. This, in conjunction with the preliminary findings of abundant hydrothermal mineralisation (calcite, anhydrite, quartz) in eruption ejecta, suggests that the main volcanic conduits had become effectively sealed during the interval since the last eruption. Calcite-hosted fluid inclusions are CO2 clathrate-bearing, and have relatively low homogenisation temperatures (165-180 °C), suggesting that the seal environment was both gas-charged and shallowly seated (seal, leading to growth of a vapour-static gas cap beneath the seal, and its eventual failure through elevated pore pressures.

  1. The experimental and numerical investigation of a grooved vapor chamber

    International Nuclear Information System (INIS)

    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 fchamber 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

  2. Comparison of GPS precipitable water vapor and meteorological parameters during rainfalls in Tehran

    Science.gov (United States)

    Sharifi, Mohammad Ali; Sam Khaniani, Ali; Joghataei, Mohammad

    2015-05-01

    In this study, the sensing of water vapor using the global positioning system (GPS) was investigated in Tehran. Water vapor mean temperature T m is a key parameter in conversion of GPS zenith wet delay to precipitable water vapor (PWV). Then, by using 8 years of radiosonde and surface temperature data, we achieved a new site-specific T m model in Tehran. After the comparison of Bevis et al. (J Geophys Res 97(D14):15787-15801, 1992) and the site-specific models, a mean bias error of -1.3 K was found for Bevis model, while this is less than 0.1 K for the new local model. Therefore, PWV time series were generated for the ground-based GPS site in Tehran from the beginning of 2005 to the end of 2013. Comparing the GPS with the radiosonde PWV, it was shown that the GPS can be used to measure the PWV with high precision. The root mean square error for differences between the GPS and radiosonde was derived as 1.5 mm. The PWV has significant relationship with precipitation in our case study. The thresholds of the relative humidity anomaly with different PWV anomaly related to rainfall occurrences are also considered in this research. The analyses show that use of PWV anomaly condition together with surface meteorological parameters reduces the number of false rainfall recognitions significantly.

  3. Pumping effectiveness of a magnesium vapor jet in the presence of a high power neutral beam source

    International Nuclear Information System (INIS)

    An experimental study of a superconic magnesium vapor jet neutralizer has established the effectiveness of the jet in reducing cold streaming gas from a high current neutral beam source. The removal of molecular hydrogen gas by a magnesium jet neutralizer provides a means of simplifying beamline design by improved pumping characteristics of the jet compared with conventional technology while simulataneously improving performance

  4. Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling

    International Nuclear Information System (INIS)

    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 227 m 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. (author)

  5. Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling

    Directory of Open Access Journals (Sweden)

    Wibisono

    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 227 m 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

  6. Radiative equilibrium in an atmosphere with large water vapor concentrations

    International Nuclear Information System (INIS)

    A possible cause of a worldwide equable climate is discussed, namely a canopy of pure water vapor resting on top of today's atmosphere. The layer of water vapor is assumed to compress the atmosphere beneath and mix downward only by molecular diffusion. To prevent the water vapor from condensing, its radiative equilibrium temperature must be hot enough to produce a saturation vapor pressure exceeding the total pressure due to the water vapor above. The expectation is that the temperature at the base of such a canopy is quite warm, producing extremely stable atmospheric conditions beneath. 19 refs

  7. Autocatalytic Theory of Meaning

    OpenAIRE

    Roberts, Mark D.

    1999-01-01

    Recently it has been argued that autocatalytic theory could be applied to the origin of culture. Here possible application to a theory of meaning in the philosophy of language, called radical interpretation, is commented upon and compared to previous applications.

  8. 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....

  9. Stats means business

    CERN Document Server

    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

  10. Dynamic Mean Preserving Spreads

    OpenAIRE

    Arcand, Jean-louis; Hongler, Max-olivier

    2014-01-01

    We extend the celebrated Rothschild and Stiglitz (1970) definition of Mean Preserving Spreads to scalar diffusion processes. We provide sufficient conditions under which a family of diffusion processes satisfies the dynamic counterparts to the famous Rothschild and Stiglitz integral conditions. We prove that the only Brow- nian bridge with non-constant drift that displays the Dynamic Mean-Preserving Spread (DMPS) property is given by the ballistic super-diffusive process. We...

  11. Algebraic mean field theory

    OpenAIRE

    Dankova, Ts; Rosensteel, G.

    1999-01-01

    Mean field theory has an unexpected group theoretic mathematical foundation. Instead of representation theory which applies to most group theoretic quantum models, Hartree-Fock and Hartree-Fock-Bogoliubov have been formulated in terms of coadjoint orbits for the groups U(n) and O(2n). The general theory of mean fields is formulated for any arbitrary Lie algebra {\\textbf g} of fermion operators. The moment map provides the correspondence between the Hilbert space of microscop...

  12. Preliminary characterization of a water vaporizer for resistojet applications

    Science.gov (United States)

    Morren, W. Earl

    1992-01-01

    A series of tests was conducted to explore the characteristics of a water vaporizer intended for application to resistojet propulsion systems. The objectives of these tests were to (1) observe the effect of orientation with respect to gravity on vaporizer stability, (2) characterize vaporizer efficiency and outlet conditions over a range of flow rates, and (3) measure the thrust performance of a vaporizer/resistojet thruster assembly. A laboratory model of a forced-flow, once-through water vaporizer employing a porous heat exchange medium was built and characterized over a range of flow rates and power levels of interest for application to water resistojets. In a test during which the vaporizer was rotated about a horizontal axis normal to its own axis, the outlet temperature and mass flow rate through the vaporizer remained steady. Throttlability to 30 percent of the maximum flow rate tested was demonstrated. The measured thermal efficiency of the vaporizer was near 0.9 for all tests. The water vaporizer was integrated with an engineering model multipropellant resistojet. Performance of the vaporizer/thruster assembly was measured over a narrow range of operating conditions. The maximum specific impulse measured was 234 s at a mass flow rate and specific power level (vaporizer and thruster combined) of 154 x 10(exp-6)kg/s and 6.8 MJ/kg, respectively.

  13. Water vapor in the middle atmosphere of Mars during the global dust storm in 2007

    Science.gov (United States)

    Fedorova, Anna; Bertaux, Jean-Loup; Montmessin, Franck; Korablev, Oleg; Dzuban, Ilya; Maltagliati, Luca; Clarke, John

    2015-04-01

    Recent observations of the Martian hydrogen corona in the UV H Ly-? emission by Hubble Space Telescope (HST) [Clarke et al., 2014] and the SPICAM UV spectrometer on Mars Express [Chaffin et al., 2014] reported its rapid change an order of magnitude for the short period of a few months in 2007 (MY 28), which is inconsistent with the existing models. One proposed explanation of observed decrease in coronal emission is that during the global dust storm water vapor can be transported to higher altitudes where the rate of photodissociation by near-UV sunlight increases, providing an additional source of hydrogen for the upper atmosphere. Since 2004 the SPICAM IR spectrometer on Mars-Express carries out measurements of the vertical distribution of water vapor in the 1.38 µm band and aerosol properties in the middle atmosphere of Mars by means of solar occultations. We presents here vertical profiles of water vapor at Ls = 250-310° during the dust storm of MY28. SPICAM observations confirm the increase of the H2O content at 60 km from Ls=268° to Ls=285° an order of magnitude for the northern hemisphere and in 3-4 times for the southern hemisphere. Nevertheless, the photochemical modeling is required to estimate a contribution of observed water abundance to the hydrogen corona. The interannual variability of water vapor vertical distribution for the southern summer season will be also presented.

  14. Particle-size distribution in capacitor discharge vaporization of uranium dioxide

    International Nuclear Information System (INIS)

    A homogeneous nucleation-condensation growth model was developed for calculating particle-size distributions measured in capacitor discharge vaporization (CDV) experiments conducted at the Oak Ridge National Laboratory. Uranium dioxide pellets were partially vaporized in an argon environment by rapid energy deposition through capacitor discharge. This was followed by rapid expansion and subsequent condensation of the UO2 vapor. Measured primary particle-size distributions of the resulting aerosols were lognormal, with a geometric mean particle diameter of (0.014 + or - 0.002) ?m and a geometric standard deviation of 1.7 + or - 0.1. It was postulated that the expanding UO2 vapor compressed the surrounding argon as in a spherical shock tube and that the aerosol was generated by homogeneous nucleation and condensation growth in the resulting rarefaction wave. The calculated motion of the UO2-argon interface is in approximate agreement with the movies of the expansion process. The calculated particle-size distributions are in agreement with the measured distributions except at the large particle end. This agreement indicates that the small primary particles from the CDV tests resulted from homogeneous nucleation and condensation growth, as assumed in the analytical model

  15. Diversion Radiometer Data for Water Vapor Direction Delay

    Directory of Open Access Journals (Sweden)

    Ahmad Khalf Aldhafari

    2013-02-01

    Full Text Available The radiometers for probing water vapor, temperature and cloud liquid water do not show the highaccuracy and stability which is needed for some applicationslike turbulent weather conditions. The Form of direction delayfrom atmospheric water vapor is a main error source ingeodetic measurements made with VLBI. A dual channelwater vapor radiometer, operating near the 22GHz watervapor line , and measuring water vapor-induced delay withgood conditions. Theory shows that water vapor directiondelay ?LV is related to a linear combination of saturation corrected sky brightness temperatures, measured the watervapor line. Sky brightness temperatures are saturationcorrectedor "linearized" using estimates of effective skytemperature made from surface temperature. A systematicmethod for reducing dual-frequency water vapor radiometerdata to water vapor path delay has been developed Coefficients are found from a regression of theoreticalbrightness temperatures versus radiosonde measured delay.Regression solutions are constrained to remove liquid watercontributions and to give the correct slope for radiometerversus radiosonde path delay.

  16. The effect of vapor concentration on the formation of nanowires

    International Nuclear Information System (INIS)

    Full text: During the synthesis of MgO, Si-SiOx (x=1-2) nanowires using chemical vapor deposition (CVD) method in the presence of catalysts, we found that the concentration of vapor can significantly affect the morphology and formation of final products. When Mg vapor concentration was low, MgO nanowires and nanoribbons formed via vapor-liquid-solid (VLS) or vapor-solid (VS) mechanisms; when Mg vapor concentration was very high, only micro-sized MgO whiskers and ribbons were obtained, which usually grow via VS mechanism. Similarly, different concentrations of Si and SiOx vapor lead to the products of Si and SiOx nanoswires and growth mechanisms of VLS and VS, respectively. Copyright (2005) Australian Institute of Physics

  17. Vaporization behavior of non-stoichiometric thorium monocarbides

    International Nuclear Information System (INIS)

    Vapor pressure of non-stoichiometric ThC was determined based on the measurement of vaporization behavior of ThC/sub x/O/sub y/. First, the partial vapor pressures of ThO(g), Th(g), and CO(g) over ThC/sub x/O/sub y/ were determined. Then, after the vapor signal of ThO(g) was attenuated, the vapor pressure of Th(g) over ThC(s) was measured and the enthalpy of vaporization of Th(g) was derived. The observed change with composition of vaporization properties of ThC(s) was similar with that of UC(s) of literature. The phase boundary of the ThC + ThC/sub 2/ region was suggested to exist between ThC/sub 1.007/ and ThC/sub 1.074/ for the temperature range of 2100 to 2300K

  18. Estimating evaporative vapor generation from automobiles based on parking activities.

    Science.gov (United States)

    Dong, Xinyi; Tschantz, Michael; Fu, Joshua S

    2015-07-01

    A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade-Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5-8% less than calculation without considering parking activity. PMID:25818089

  19. Atomic vapor spectroscopy in integrated photonic structures

    CERN Document Server

    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.

  20. Soil vapor extraction enhanced by oscillatory flow

    Energy Technology Data Exchange (ETDEWEB)

    Neeper, D.A.

    1991-01-01

    The rate of contaminant removal by soil vapor extraction becomes low when diffusion limits the transfer of vapor from the soil to the channels in the soil where air preferentially flows. This paper suggests that adding an oscillatory component to the pressure and velocity of the subsurface air may increase the transport to the channels of flow, and thereby increase the rate of extraction, when the diffusion limit occurs. Three physical mechanisms by which oscillatory flow may increase the transport are described. Algebraic expressions and numerical estimates are given for the penetration of oscillatory pressure into various soils. Exploratory experiments with a laboratory soil column indicate enhanced extraction when an oscillatory component is superimposed upon nonequilibrium steady flow. 30 refs., 4 figs., 2 tabs.

  1. Algebraic Reconstruction Algorithm of Vapor Tomography

    Directory of Open Access Journals (Sweden)

    HE Lin

    2015-01-01

    Full Text Available While applying algebraic reconstruction algorithm in vapor tomography, problems have to be solved with respect to constructing the constraint condition, selecting the initial value, calculating optimal relaxation factor and deciding the iteration termination condition. Golden section search method and NCP termination rule are given to solve the latter two problems, respectively. Eight algebraic reconstruction algorithms, including Kaczmarz, Randkaczmarz, Symkaczmarz, SART, Landweber, Cimmino, CAV and DROP algorithm, are comparatively analyzed and tested by the data from SatRef station in Hong Kong. The results show that all the eight algorithms can satisfy the requirements of vapor tomography and the iteration termination condition is more important than the relaxation condition. While the golden section method and NCP method are used, the CAV algorithm performs best, and then the Cimmino algorithm.

  2. Modelling vaporous cavitation on fluid transients

    CERN Document Server

    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.

  3. Liquid-liquid contact in vapor explosion

    International Nuclear Information System (INIS)

    The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials

  4. Vaporization of atherosclerotic plaques by spark erosion

    OpenAIRE

    Slager, C. J.; Essed, C. E.; Schuurbiers, J. C. H.; Bom, N.; Serruys, P. W. J. C.; Meester, G. T.

    1985-01-01

    An 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 documented histologically in vitro from 30 atherosclerotic segments of six human aortic autopsy specimens. Craters with a constant area and a depth that varied according to the duration of application were produce...

  5. DuPont Chemical Vapor Technical Report

    International Nuclear Information System (INIS)

    DuPont Safety Resources was tasked with reviewing the current chemical vapor control practices and providing preventive recommendations on best commercial techniques to control worker exposures. The increased focus of the tank closure project to meet the 2024 Tri-Party Agreement (TPA) milestones has surfaced concerns among some CH2MHill employees and other interested parties. CH2MHill is committed to providing a safe working environment for employees and desires to safely manage the tank farm operations using appropriate control measures. To address worker concerns, CH2MHill has chartered a ''Chemical Vapors Project'' to integrate the activities of multiple CH2MHill project teams, and solicit the expertise of external resources, including an independent Industrial Hygiene expert panel, a communications consultant, and DuPont Safety Resources. Over a three-month time period, DuPont worked with CH2MHill ESH and Q, Industrial Hygiene, Engineering, and the independent expert panel to perform the assessment. The process included overview presentations, formal interviews, informal discussions, documentation review, and literature review. DuPont Safety Resources concluded that it is highly unlikely that workers in the tank farms are exposed to chemicals above established standards. Additionally, the conventional and radiological chemistry is understood, the inherent chemical hazards are known, and the risk associated with chemical vapor exposure is properly managed. The assepor exposure is properly managed. The assessment highlighted management's commitment to addressing chemical vapor hazards and controlling the associated risks. Additionally, we found the Industrial Hygiene staff to be technically competent and well motivated. The tank characterization data resides in a comprehensive database containing the tank chemical compositions and relevant airborne concentrations

  6. Ceramic composites by chemical vapor infiltration

    International Nuclear Information System (INIS)

    Composites consisting of silicon carbide matrices reinforced with continuous ceramic fibers are being developed for high-temperature structural applications. Chemical vapor deposition (CVD) techniques are very effective in fabricating composites with high strengths and exceptional fracture toughness. Mechanical properties of infiltrated composites are controlled by the strength of the interfacial bond between the fibers and matrix. This paper describes two CVD techniques and reviews the models being developed to better understand and control the infiltration process

  7. Chemical vapor deposition of hydrogenated amorphous silicon

    International Nuclear Information System (INIS)

    Hydrogenated amorphous silicon films are made by atmospheric pressure chemical vapor deposition from polysilanes between 430 and 4800C. The films have hole diffusion lengths up to 0.4 ?m, as measured by the surface photovoltage technique. Oxygen impurities are shown to reduce the diffusion length. Stainless-steel and crystalline silicon substrates give slightly different results, implying that contamination is introduced by the substrates

  8. Coherently enhanced Raman scattering in atomic vapor

    OpenAIRE

    Yuan, Chun-hua; Chen, L. Q.; Jing, Jietai; Ou, Z. Y.; Zhang, Weiping

    2010-01-01

    We present a scheme to obtain the coherently enhanced Raman scattering in atomic vapor which is induced by a spin wave initially written by a weak write laser. The enhancement of Raman scattering is dependent on the number and the spatial distribution of the flipped atoms generated by the weak write laser. Such an enhanced Raman scattering may have practical applications in quantum information, nonlinear optics and laser spectroscopy because of its simplicity.

  9. Acoustic Droplet Vaporization in Biology and Medicine

    OpenAIRE

    Chung-Yin Lin; William G. Pitt

    2013-01-01

    This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV) in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but i...

  10. Liquid and Vapor Flow in Superheated Rock

    Science.gov (United States)

    Woods, Andrew W.

    1999-01-01

    In this review, we describe the dynamics and thermodynamics of liquid and vapor flow through hot fractured rock. Such flows occur in geothermal reservoirs and have important implications for geothermal power generation; we describe both forced flows associated with liquid injection into such systems, and natural convective flows associated with the vertical heat transfer through such systems. First we focus on permeable media and describe the heat transfer of single-phase liquid or vapor flow through a medium of different temperature. Then we consider the dynamics and thermodynamics of a liquid front as it advances into a superheated region and boils. The morphological stability of such an interface is discussed, and we describe conditions under which the interface breaks down to form a two-phase zone between the liquid and vapor. We next examine the heat transfer and boiling in gravity-driven flows advancing through a superheated permeable rock, identifying that at large times such currents asymptote to a family of similarity solutions. In the second part of the review, we describe the analogous heat transfer and boiling processes associated with liquid flow along a fracture embedded in an impermeable rock. We describe some simple asymptotic solutions for the temperature distribution in the bounding rock, which reveal that in the fracture, a two-phase boiling region develops between the purely liquid and purely vapor zones. Model predictions are successfully tested with laboratory experiments. In the final section of the review, we briefly discuss natural convective flows, illustrating how single-phase and two-phase convective regions interact and in some cases produce instability.

  11. Investigation of a pulse manganese vapor laser

    Energy Technology Data Exchange (ETDEWEB)

    Isaev, A.A.; Kazaryan, M.A.; Petrash, G.G.; Cherezov, V.M.

    1976-08-01

    An investigation was made of a pulse manganese vapor laser operated under self-heating conditions at a high pulse repetition frequency. The output power was determined as a function of gas-discharge conditions. The best output parameters were obtained using helium as a buffer gas: the average output power was found to be 2.1 W, the peak power was 24 kW, and the efficiency was 0.2%. (AIP)

  12. Ultraviolet-emitting gold vapor laser

    Energy Technology Data Exchange (ETDEWEB)

    Markova, S.V.; Petrash, G.G.; Cherezov, V.M.

    1978-07-01

    An investigation was made of pulsed stimulated emission of ultraviolet radiation from gold vapor in discharge mixtures with helium, neon, and argon. In a discharge with neon, the average output power at the 312.2 nm wavelength was 1.2 W and the efficiency was 0.03%. At 627.8 nm, under similar excitation conditions, the average output power was 6 W and the efficiency was 0.2%.

  13. Electrochemical vapor deposition of oxide films

    International Nuclear Information System (INIS)

    In this paper electrochemical vapor deposition (EVD) of yttria stabilized zirconia (YSZ) on a porous substrate, and In2O3 and SnO2 on YSZ are presented. Thermodynamic and kinetic calculations for YSZ deposition are made for limiting cases which serve to describe the process. The effects of gas phase composition and solid state transport properties of the growing film and substrate are described

  14. Combined rankine and vapor compression cycles

    Science.gov (United States)

    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.

  15. Water vapor adsorption characteristics of honeycomb adsorbents

    International Nuclear Information System (INIS)

    For large volume air clean-up in nuclear fusion facilities, honeycomb-type adsorbents offer a useful advantage in terms of their low-pressure drop. In this study, two different honeycomb-type adsorbents (honeycomb-K and honeycomb-N) and pebble-type adsorbents were used as samples and the water vapor adsorption performance of each adsorbent was examined by changing temperature, concentration of water vapor and flow rate. The honeycomb-K and honeycomb-N adsorbents included zeolite-4A or zeolite-5A with a 50% clay binder and with a 15% sepiolite binder, respectively. The shapes of cells in honeycomb-K and honeycomb-N are triangles with 1 mm sides and squares with 1 mm sides, respectively, and the cell densities of the both adsorbents were 200 CPSI (cells/in.2). The adsorption capacity for water vapor on the honeycomb-K adsorbent was comparable to that on the pebble-type adsorbent, while the adsorption capacity on the honeycomb-N adsorbent was lower. The adsorption rates of honeycomb-K and honeycomb-N adsorbents were higher than that of the pebble-type adsorbent. The honeycomb-K adsorbent containing zeolite-5A showed a higher adsorption rate than that containing zeolite-4A. Thus, honeycomb-K containing zeolite-5A adsorbent could be applicable to air cleanup systems in terms of both adsorption capacity and rate.

  16. Microscale ethanol vapor ejector and injector

    Science.gov (United States)

    Gardner, William G.; Wang, Ivan; Brikner, Natalya A.; Jaworski, Justin W.; Protz, Jonathan M.

    2010-04-01

    Two non-rotating pumping components, a jet ejector and injector, were designed and tested. Two jet ejectors were designed and tested to induce a suction draft using a supersonic micronozzle. Three-dimensional axisymmetric nozzles were microfabricated to produce throat diameters of 187 ?m and 733 ?m with design expansion ratios near 2.5:1. The motive nozzles achieved design mass flow efficiencies above 95% compared to isentropic calculations. Ethanol vapor was used to motivate and entrain ambient air. Experimental data indicate that the ejector can produce a sufficient suction draft to satisfy both microengine mass flow and power off-take requirements to enable its substitution for high speed microscale pumping turbomachinery. An ethanol vapor driven injector component was designed and tested to pressurize feed liquid ethanol. The injector was supplied with 2.70 atmosphere ethanol vapor and pumped liquid ethanol up to a total pressure of 3.02 atmospheres. Dynamic pressure at the exit of the injector was computed by measuring the displacement of a cantilevered beam placed over the outlet stream. The injector employed a three-dimensional axisymmetric nozzle with a throat diameter of 733 ?m and a three-dimensional converging axisymmetric nozzle. The experimental data indicate that the injector can pump feed liquid into a pressurized boiler, enabling small scale liquid pumping without any moving parts. Microscale injectors could enable microscale engines and rockets to satisfy pumping and feedheating requirements without high speed microscale turbomachinery.

  17. Designing polymer surfaces via vapor deposition

    Directory of Open Access Journals (Sweden)

    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.

  18. Water vapor distribution in protoplanetary disks

    CERN Document Server

    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 ...

  19. Characterization of Acoustic Droplet Vaporization Using MRI

    Science.gov (United States)

    Li, David; Allen, Steven; Hernandez-Garcia, Luis; Bull, Joseph

    2013-11-01

    Acoustic droplet vaporization (ADV) is the selective vaporization of liquid droplets to form larger gas bubbles. The ADV process is currently being researched for biomedical applications such as gas embolotherapy, drug delivery, and phase-change contrast agents. In this study an albumin encapsulated dodecafluoropentane (DDFP, CAS: 678-26-2) microdroplet suspension was vaporized using a single element focused (f/2, D = 19 mm) 3.5 MHz transducer (Panametrics A321S, Olympus, Waltham, MA). The resulting DDFP bubble clouds were imaged using both bright field microscopy and MRI (Varian 7T, Agilent Technologies Inc., Santa Clara, CA). Field distortions due to DDFP bubble generation were characterized against the bright field images as a function of acoustic power and bubble cloud size. Experimentally a direct correlation between bubble cloud dimensions generated and field distortions seen in the MRI was observed. Additionally, MR velocimetry was used to measure the flow field resulting from ADV. The field distortions due to the bubbles were further characterized by modeling Maxwell's equations using COMSOL (COMSOL Inc., Burlington, MA). The ability to characterize ADV with alternative imaging modalities may prove useful in further development of ADV based biomedical therapies.

  20. Biofiltration of gasoline vapor by compost media

    International Nuclear Information System (INIS)

    A compost medium was effective in biofiltering gasoline vapor. - Gasoline vapor was treated using a compost biofilter operated in upflow mode over 4 months. The gas velocity was 6 m/h, yielding an empty bed retention time (EBRT) of 10 min. Benzene, toluene, ethylbenzene and xylene (BTEX) and total petroleum hydrocarbon (TPH) removal efficiencies remained fairly stable approximately 15 days after biofilter start-up. The average removal efficiencies of TPH and BTEX were 80 and 85%, respectively, during 4 months of stable operation. Biodegradation portions of the treated TPH and BTEX were 60 and 64%, respectively. When the influent concentration of TPH was less than 7800 mg TPH/m3, approximately 50% of TPH in the gas stream was removed in the lower half of the biofilter. When the influent concentration of BTEX was less than 720 mg BTEX/m3, over 75% of BTEX in the gas stream was removed in the lower half of the biofilter. Benzene removal efficiency was the lowest among BTEX. A pressure drop could not be detected over a 1-m bed height at a gas velocity of 6 m/h after approximately 4 months of operation. Results demonstrated that BTEX in gasoline vapor could be treated effectively using a compost biofilter