WorldWideScience
 
 
1

Characteristics of the mean water vapor transport over monsoon asia  

Science.gov (United States)

Based on ECMWF monthly mean data from January 1980 to December 1989, characteristics of the three-dimensional structure of the mean water vapor transport over Monsoon Asia are described, and the more im-portant features of the different regional water vapor transport in the Indian Monsoon region and the East Asian Monsoon region are analyzed. It is found that there is a moist tongue extending from the equator poleward to the Asian Monsoon region. The three-dimensional distributions of the mean water vapor transport fields over the entire globe reflect clearly the asymmetry of the Asian Monsoon system, and the existence of a counter-Hadley monsoon circulation. The moisture conver-gence (divergence) area in Asia coincides with the confluent (diffluent) zone of the monsoon circulation. Furthermore, the moist features of the two sub-regions of the Asian Monsoon area are differ-ent both in their magnitudes and in their seasonal variations.

Yi, Lan

1995-05-01

2

Mercury vapor control by means of corona discharge  

Energy Technology Data Exchange (ETDEWEB)

The work reported here describes the construction and performance of a novel corona discharge flue gas reactor designed to oxidize mercury vapor, allowing the mercuric oxide to be subsequently captured in a downstream particulate control device. A corona discharge in flue gas produces oxidizing radicals, such as OH and atomic oxygen, which can then react with elemental mercury. Optimum performance demands that the corona discharge, and hence the oxidizing radicals, be uniformly distributed within the flow volume of the reactor. When a uniform volume distribution of electrons is achieved, then uniform exposure and treatment of the gas is assured, and maximum energy efficiency can be obtained. By means of a laboratory based, pilot scale system, it is shown that the spatially distributed corona discharge produced by the corona reactor operating at low power level and short residence time yields a high level of mercury vapor oxidation. The mercuric oxide, in the form of solid particles, can then be removed by a conventional electrostatic precipitator or fabric filter. It is also shown that low temperature, high humidity conditions enhance mercury oxidation. For an application to solid waste incineration, this suggests the placement of the reactor downstream of the spray dryer and upstream of the fabric filter. Economic analysis indicates that this method of mercury vapor control is very competitive with adsorption by activated carbon. For example, if mercury control regulations are promulgated for coal burning power plants, the corona discharge technology could potentially save the US utility industry and electricity consumers up to 250 million dollars per year. 10 refs., 6 figs., 2 tabs.

Helfritch, D.; Harmon, G.; Feldman, P. [Environmental Elements Corp., Baltimore, MD (United States)

1996-12-31

3

Fluid Conduit.  

Science.gov (United States)

A fluid conduit for flowing electrically conductive fluids includes an electrically conductive pipe, an electrically conductive rod extending axially through the pipe and centrally thereof, a first power source in electrical communication with the pipe an...

C. W. Henoch P. J. Hendricks

1999-01-01

4

Vapor Pressure and Mean Adsorption Time of Pyromellitic Dianhydride and 4,4?-Oxidianiline  

Science.gov (United States)

Thermogravimetry (TG) measurements taken at pressures ranging from 10-1 to 10-3 Pa are used to calculate the vapor pressure of pyromellitic dianhydride (PMDA) and 4,4?-oxidianiline (ODA). The vapor pressure calculated for PMDA is closely agrees with to those reported by Pethe et al.., Elshazly and Salem. For ODA, the calculated vapor pressure fits exactly on the curve obtained by Salem. The enthalpy is also calculated. The activation energy of desorption is found to be nearly equal to the enthalpy. The adsorption and desorption rates for both PMDA and ODA at various substrate temperatures are also observed. The mean adsorption time, ? calculated for ODA is several orders of magnitude larger than that for PMDA. 1:1 doses of ODA and PMDA therefore produce imine bonds which lead to the formation of thermally unstable films.

Dutt, Radhika; Takahashi, Yoshikazu; Iijima, Masayuki

1999-06-01

5

Monitoring Water Vapor By Means of A Gps-reference Station Network In Austria  

Science.gov (United States)

GPS has become an important tool both in navigation and in precise point position- ing. So far, the water vapor content of the troposphere was considered as one of the limiting error sources. In view of the interest of meteorologists in the wet component of the troposphere as a valuable tool for Numerical Weather Prediction, the potential of ground based GPS measurements for estimating tropospheric water vapor has been demonstrated by several projects e.g. MAGIC , COST-716. Nowadays the accuracy of water vapor estimates based on microwave data is comparable to radiosonde and radiometer data. Compared to these measurements GPS lacks of vertical resolution but offers a low cost monitoring of water vapor with high temporal resolution. We make use of the continuous measurements of the GPS/GLONASS reference sta- tion network in Austria extended with surrounding stations of the IGS and EUREF- network. Currently the network under consideration consists of 16 sites with a mean distance of about 60 km. We calculate the zenith wet delays for a period of two weeks in January 2002. Subsequently the results will be compared to contributions of 5 dif- ferent processing centers of the COST-716 project SExploitation of Ground Based & cedil;GPS for Climate and NWPT and with zenith path delay estimates provided by the IGS. As meteorologists need the water vapor within less than two hours, the parame- ters must be delivered in near real-time. This causes special considerations concerning the availability and reliability of observation data and the satellite orbit information and requires furthermore the automatisation of the calculations.

Fragner, E.; Weber, R.

6

Automated Conduit Unloading  

Science.gov (United States)

Large, cumbersome pipes removed from trailer by one operator. Swiveltruck trailer carries conduit and unloads it. Vertical bins interconnected by web belts that elevate conduit sections for delivery by gravity to unloading point. Trailer loaded with slurry-pipe sections 6 inches (15.2 centimeters) in diameter, but bin width readily changed to hold other sizes. Simple adjustments in bin-partition and web-belt positions needed to adapt system to different conduit cross sections.

Lewis, E. V.

1986-01-01

7

Glycol reboiler vapor condenser  

Energy Technology Data Exchange (ETDEWEB)

A method is described for controlling the emission of aromatic compounds from a glycol reboiler, including steam and vaporized hydrocarbons, during glycol dehydration, comprising the steps of: (a) heating used glycol and water in said glycol reboiler to a temperature in the range of 350 to 400 degrees Fahrenheit; (b) directing steam and vaporized hydrocarbons from said glycol reboiler to a centrally disposed cylinder in a vapor condenser by a first conduit; (c) providing said vapor condenser with a cooling water spray through a second conduit connected to a source of liquid water and said centrally disposed cylinder for spraying said steam and said vaporized hydrocarbons to thereby change said steam and said vaporized hydrocarbons to a liquid phase; (d) collecting the water and hydrocarbons in said liquid phase in an accumulator; (e) withdrawing said water and hydrocarbons in said liquid phase from said accumulator through a third conduit; (f) withdrawing the remaining vaporized hydrocarbons from said accumulator through a fourth conduit; (g) providing said vapor condenser with cooling water for a water jacket surrounding said vapor condenser through a fifth conduit; and (h) burning said withdrawn remaining vaporized hydrocarbons in a burner connected to said fourth conduit and said glycol reboiler; whereby said emissions of aromatic compounds from glycol dehydration are prevented from escaping into the atmosphere. The separation equipment necessary for this emission control method is also described.

McGrew, R.; Broussard, J.P.

1993-08-10

8

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

CERN Document Server

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

International Organization for Standardization. Geneva

2003-01-01

9

Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 2: Orifice plates  

CERN Multimedia

ISO 5167-2:2003 specifies the geometry and method of use (installation and operating conditions) of orifice plates when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit. It also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-2:2003 is applicable to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with D and D/2 pressure tappings. Other pressure tappings such as vena contracta and pipe tappings have been used with orifice plates but are not covered by ISO 5167-2:2003. ISO 5167-2:2003 is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow. It does not cover the use of orifice plates in pipe sizes less than 50 mm or more than 1 000 mm, or for pipe Reynol...

International Organization for Standardization. Geneva

2003-01-01

10

Seal arrangement for intersecting conduits  

Energy Technology Data Exchange (ETDEWEB)

A seal arrangement in which two intersecting conduits are sealed from each other. A sleeve insert is locked in a sealed relationship within one conduit enclosing the openings of the intersecting conduit.

Goedicke, Friedrich E. (Trafford, PA)

1980-01-01

11

Investigation of vaporization thermodynamics of SrUO{sub 3} by means of mass spectrometry  

Energy Technology Data Exchange (ETDEWEB)

The vaporization properties of SrUO{sub 3} have been studied for the first time by means of Knudsen effusion mass spectrometry over a temperature range of 1534 to 1917 K. The sample used was a mixture of SrUO{sub 3} and 23 wt% UO{sub 2}. The main vapor species over the mixture were Sr(g), UO{sub 2}(g) and SrO(g) in decreasing order of their partial pressures. The standard enthalpy of formation of SrUO{sub 3} was evaluated by using the second law and the third law treatments, in which estimated values of H (T)-H (298.15) and gef(T) were employed on account of absence of published data. The standard enthalpies of the formation of SrMO{sub 3} with pseudo-cubic perovskite structure, where M stands for metallic cations with the valence of four, were also discussed based on the relationship between the ionic radii of M{sup 4+} of the compounds and their enthalpy values. (orig.).

Huang, J. [Tokyo Univ. (Japan). Faculty of Engineering; Yamawaki, M. [Tokyo Univ. (Japan). Faculty of Engineering; Yamaguchi, K. [Tokyo Univ. (Japan). Faculty of Engineering; Yasumoto, M. [Research Center for Nuclear Science and Technology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113 (Japan); Sakurai, H. [Nippon Nuclear Fuel Development Co., 2163 Narita-cho, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki-ken 311-13 (Japan); Suzuki, Y. [Department of Chemistry and Fuel Research, Japan Atomic Energy Research Institute, 3607 Narita-cho, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki-ken 319-11 (Japan)

1997-08-01

12

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

2013-09-01

13

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

1986-01-01

14

Conduit purging device and method  

Science.gov (United States)

A device for purging gas comprises a conduit assembly defining an interior volume. The conduit assembly comprises a first conduit portion having an open first end and an open second end and a second conduit portion having an open first end and a closed second end. The open second end of the first conduit portion is disposed proximate to the open first end of the second conduit portion to define a weld region. The device further comprises a supply element supplying a gas to the interior volume at a substantially constant rate and a vent element venting the gas from the interior volume at a rate that maintains the gas in the interior volume within a pressure range suitable to hold a weld bead in the weld region in equilibrium during formation of a weld to join the first conduit portion and the second conduit portion.

Wilks, Michael T. (Inventor)

2011-01-01

15

Flexible cryogenic conduit  

Science.gov (United States)

A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament.

Brindza, Paul Daniel (Yorktown, VA); Wines, Robin Renee (Norfolk, VA); Takacs, James Joseph (Hayes, VA)

1999-01-01

16

Flexible cryogenic conduit  

International Nuclear Information System (INIS)

A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

1998-04-16

17

Managing complications II: conduit failure and conduit airway fistulas  

Science.gov (United States)

Conduit failure and conduit airway fistula are rare complications after esophagectomy, however they can be catastrophic resulting in high mortality. Survivors can expect a prolonged hospital course with multiple interventions and an extended period of time prior to being able to resume oral nutrition. High index of suspicion can aid in early diagnosis. Conduit failure usually requires a period of proximal esophageal diversion and staged reconstruction. Conduit airway fistulas may be amenable to endoscopic repair but this has a high failure rate and many patients will require surgical repair with closure of the fistula and interposition of vascularized tissue to minimize recurrence.

Mehta, Christopher K.

2014-01-01

18

Conduit Coating Abrasion Testing  

Science.gov (United States)

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.

Sullivan, Mary K.

2013-01-01

19

47 CFR 32.2441 - Conduit systems.  

Science.gov (United States)

...2010-10-01 2010-10-01 false Conduit systems. 32.2441 Section 32...Balance Sheet Accounts § 32.2441 Conduit systems. (a) This account shall include the original cost of conduit, whether underground, in...

2010-10-01

20

76 FR 76895 - Conduit Financing Arrangements  

Science.gov (United States)

...CFR Part 1 [TD 9562] RIN 1545-BH77 Conduit Financing Arrangements AGENCY: Internal...contains final regulations relating to conduit financing arrangements. The final regulations...arrangements should be recharacterized as a conduit financing arrangement. DATES:...

2011-12-09

 
 
 
 
21

77 FR 22480 - Conduit Financing Arrangements; Correction  

Science.gov (United States)

...CFR Part 1 [TD 9562] RIN 1545-BH77 Conduit Financing Arrangements; Correction AGENCY...76 FR 76895) providing guidance on conduit financing arrangements. The final regulations...arrangements should be recharacterized as a conduit financing arrangement. DATES: This...

2012-04-16

22

Conduit coupling assembly  

International Nuclear Information System (INIS)

A conduit coupling assembly for coupling pipes with an interposed seal has a first part for receiving a pipe and is in splined engagement with a bush fixed to a pipe. A second part having radial fingers so that it can be turned by a manipulator, has a threaded engagement with the first part which is the same hand but different pitch to a threaded engagement between the second part and the bush. Pitches of 8:7 for couplings will give a mechanical advantage of 56:1 thus reducing the force needed to obtain a given axial movement of the bush and thus of the pipe and compression of the seal. (author)

1988-06-29

23

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

Science.gov (United States)

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

Song, DongSeob; Boutiouta, Seddik

2014-05-01

24

CONDUIT: Control Designer's Unified Interface  

Science.gov (United States)

CONDUIT, which stands for control designer's unified interface, is a computer software package. Its purpose is to assist a human control system designer in designing control systems for aircraft. At the present time CONDUIT is being used by most of the major U. S. rotorcraft and fixed-wing aircraft manufacturers to assist in the design of stability and control augmentation systems. Work is also continuing on the development of additional features for CONDUIT, including tools for analyzing the sensitivity of solutions, and on further enhancements to the basic package. The purpose of this paper is to describe CONDUIT, its operation, and the sensitivity tools that are being developed for inclusion in the next release of the package.

Levine, William S.; Tischler, Mark B.

1999-01-01

25

Conduit for Transferring Molten Silicon  

Science.gov (United States)

Proposed three-part conduit transfers pure silicon between crucibles. Four-strip heater augments layers of insulation to prevent molten silicon from cooling and solidifying during transfer. Since melt is maintained at temperature relatively close to fusion point, to minimize quartz erosion, even relatively-minor heat losses precipitate solidification and terminate work in progress. Several crucibles may be fed through conduits from central crucible. Each would be contained in its own compartment under inert atmosphere.

Fiegl, G.; Torbet, W.

1982-01-01

26

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)

1980-01-01

27

Long-term follow-up of patients with extracardiac valved conduits.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Seventeen patients having extracardiac valved conduits placed between the right ventricle and pulmonary artery were followed for 7 to 87 months postoperatively (mean, 42 months), at the Heart Institute, Kenritsu Amagasaki Hospital, Japan. There were no late deaths in the study group. Three conduits have been replaced, all because of conduit stenosis. In two-dimensional echocardiographic examinations, commissural fusion and calcification of the valve were noted in 6 out of 16 xenograft valv...

Sano, Shunji; Yokota, Yoshio; Makino, Seiichiro

1989-01-01

28

Detection of 20Na atoms and measurement of sodium-vapor densities by means of atomic-resonance fluorescence  

International Nuclear Information System (INIS)

The method of atomic-resonance fluorescence has been applied to the detection of very small concentrations of radioactive 20Na atoms (9 m-3). The 20Na isotope is produced by the reaction 20Ne(p,n)20Na by passing a 20 MeV proton beam through a neon gas target of density 3.5 times 1024 atoms/m3. A beam of a continuous-wave dye laser tuned to the D2 line of sodium is transmitted through the production region and the fluorescence light is detected by means of photon counting. A digital synchronous-detection technique has been applied to measure the time-dependent behavior of the 20Na atom density shortly after a proton irradiation. This behavior is determined both by radioactive decay and by diffusion of the atoms out of the production region. The absolute 20Na atom density has been estimated, using Rayleigh scattering of the laser beam on the neon gas for calibration of the optical system. The density of neutral 20Na atoms appeared to be an order of magnitude lower than the density produced. The detection method has also been used to measure the temperature dependence of saturated sodium-vapor density down to 3 times 1011 atoms/m3 (292 K). (auth)

1975-01-01

29

Bentall Operation with Valved Homograft Conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lesions of the ascending aorta associated with aortic valve disease are usually treated by implanting a prosthetic valved conduit (Bentall procedure). In this report, we present our experience in which a valved homograft conduit was used for the procedure.

Choudhary, Shiv K.; Talwar, Sachin; Kumar, A. Sampath

2000-01-01

30

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)

2009-07-20

31

Limitations of Conduits in Peripheral Nerve Repairs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nerve conduits have emerged as alternatives to autologous nerve grafts, but their use in large-diameter nerve deficits remains untested. We report four patients who underwent repair of large-diameter nerves using absorbable nerve conduits and discuss the failed clinical outcomes. The reported cases demonstrate the importance of evaluating the length, diameter, and function of nerves undergoing conduit repair. In large-diameter nerves, the use of conduits should be carefully considered.

Moore, Amy M.; Kasukurthi, Rahul; Magill, Christina K.; Farhadi, H. Francis; Borschel, Gregory H.; Mackinnon, Susan E.

2009-01-01

32

Ductile compaction in volcanic conduits  

Science.gov (United States)

Silicic magmas typically outgas through connected pore and crack networks with a high gas permeability without the need for decoupled movement of pores in the melt. It is the efficiency with which this process can occur which governs the pressure in the pore network. However, such a connected coupled network is generally mechanically unstable and will relax until volume equilibrium when the pores become smaller and isolated. Consequently, gas permeability can be reduced during densification. Cycles of outgassing events recorded in gas monitoring data show that permeable flow of volatiles is often transient, which is interpreted to reflect magma densification and the closing of pore-networks. Understanding the timescale over which this densification process occurs is critical to refining conduit models that seek to predict the pressure evolution in a pore-network leading to eruptions. We conduct uniaxial compaction experiments to parameterize non-linear creep and relaxation processes that occur in magmas with total pore fractions 0.2-0.85. We analyze our results by applying both viscous sintering and viscoelastic deformation theory to test the applicability of currently accepted models to flow dynamics in the uppermost conduit involving highly porous magmas. We show that purely ductile compaction can occur rapidly and that pore networks can close over timescales analogous to the inter-eruptive periods observed during classic cyclic eruptions such as those at Soufriere Hills volcano, Montserrat, in 1997. At upper-conduit axial stresses (0.1-5 MPa) and magmatic temperatures (830-900 oC), we show that magmas can evolve to porosities analogous to dome lavas erupted at the same volcano. Such dramatic densification events over relatively short timescales and in the absence of brittle deformation show that permeable flow will be inhibited at upper conduit levels. We therefore propose that outgassing is a key feature at many silicic volcanoes and should be incorporated into conduit flow models.

Wadsworth, Fabian; Vasseur, Jeremie; Lavallée, Yan; Scheu, Bettina; Dingwell, Donald

2014-05-01

33

30 CFR 18.39 - Hose conduit.  

Science.gov (United States)

...1 2009-07-01 2009-07-01 false Hose conduit. 18.39 Section 18.39 Mineral Resources...Construction and Design Requirements § 18.39 Hose conduit. Hose conduit shall be provided for mechanical protection of...

2009-07-01

34

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

Energy Technology Data Exchange (ETDEWEB)

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 (P{sub s}) 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 (T{sub m}) 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 T{sub m} in terms of surface temperature (T{sub s}) 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 T{sub m}-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 T{sub m}-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 T{sub m}-based model is found to be in par with if not better than a similar site-specific T{sub m}-based model for the near equatorial station, Bangalore. A simple site-specific linear relation without accounting for the temperature effect through T{sub m} 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 T{sub m}-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 T{sub m}-based model. (orig.)

Suresh Raju, C.; Saha, K.; Thampi, B.V.; Parameswaran, K. [Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

2007-07-01

35

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

Science.gov (United States)

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.

Aminayi, Payam; Abidi, Noureddine

2013-12-01

36

QSPR modeling of heat of formation and heat of vaporization of aliphatic ketones by means of electrotopological indices  

Science.gov (United States)

This work deals with the application of the electrotopological index to calculate the enthalpies of formation and vaporization of a set of 39 linear and non-linear C 4 to C 12 aliphatic ketones within the realm of QSPR theory. Two variants of this index are employed and results show the best results are obtained when the polar and hydrophobic portion of the molecules are taken into consideration.

Marino, Damián J. G.; Peruzzo, Pablo J.; Krenkel, Germán; Castro, Eduardo A.

2003-02-01

37

Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs  

Energy Technology Data Exchange (ETDEWEB)

Large-scale water injection at The Geysers, California, hasgenerated substantial benefits in terms of sustaining reservoir pressuresand production rates, as well as improving steam composition by reducingthe content of non-condensible gases (NCGs). Two effects have beenrecognized and discussed in the literature as contributing to improvedsteam composition, (1) boiling of injectate provides a source of "clean"steam to production wells, and (2) pressurization effects induced byboiling of injected water reduce upflow of native steam with large NCGconcentrations from depth. In this paper we focus on a possibleadditional effect that could reduce NCGs in produced steam by dissolutionin a condensed aqueous phase.Boiling of injectate causes pressurizationeffects that will fairly rapidly migrate outward, away from the injectionpoint. Pressure increases will cause an increase in the saturation ofcondensed phase due to vapor adsorption on mineral surfaces, andcapillary condensation in small pores. NCGs will dissolve in theadditional condensed phase which, depending upon their solubility, mayreduce NCG concentrations in residual steam.We have analyzed thepartitioning of HCl between vapor and aqueous phases, and have performednumerical simulations of injection into superheated vapor zones. Oursimulations provide evidence that dissolution in the condensed phase canindeed reduce NCG concentrations in produced steam.

Pruess, Karsten; Spycher, Nicolas; Kneafsey, Timothy J.

2007-01-08

38

Method and apparatus for inspecting conduits  

Energy Technology Data Exchange (ETDEWEB)

An apparatus and method for ultrasonic inspection of a conduit are provided. The method involves directing a first ultrasonic pulse at a particular area of the conduit at a first angle, receiving the reflected sound from the first ultrasonic pulse, substantially simultaneously or subsequently in very close time proximity directing a second ultrasonic pulse at said area of the conduit from a substantially different angle than said first angle, receiving the reflected sound from the second ultrasonic pulse, and comparing the received sounds to determine if there is a defect in that area of the conduit. The apparatus of the invention is suitable for carrying out the above-described method. The method and apparatus of the present invention provide the ability to distinguish between sounds reflected by defects in a conduit and sounds reflected by harmless deposits associated with the conduit.

Spisak, Michael J. (Venetia, PA); Nance, Roy A. (McMurray, PA)

1997-01-01

39

Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Objectives To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React® BioConduit implanted using the Bentall procedure over ten years in a single centre. Methods Between 27/10/99 and 19/01/08, the No-React® BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from questionnaires. A cohort of patients had 2D-echocardiogram with an average of 4.3 ± 0.45 years post-operatively to evaluate valve function, calcification, and the diameter of the conduit. Results Implantation in 67 patients represented a follow-up of 371.3 patient-year. Males were 60% of the operated population, with a mean age of 67.9 ± 1.3 years (range 34.1-83.8 years, 21 of them below the age of 65. After a mean follow-up of 7.1 ± 0.3 years (range of 2.2-10.5 years, more than 50% of the survivors were in NYHA I/II and more than 60% of the survivors were angina-free (CCS 0. The overall 10-year survival following replacement of the aortic valve and root was 51%. During this period, 88% of patients were free from valved-conduit related complications leading to mortality. Post-operative echocardiography studies showed no evidence of stenosis, dilatation, calcification or thrombosis. Importantly, during the 10-year follow-up period no failures of the valved conduit were reported, suggesting that the tissue of the conduit does not structurally change (histology of one explant showed normal cusp and conduit. Conclusions The No-React® BioConduit composite stentless aortic valved conduit provides excellent long-term clinical results for aortic root replacement with few prosthesis-related complications in the first post-operative decade.

Meduoye Ayo

2011-06-01

40

Conduit to connect two fixed apparatus  

International Nuclear Information System (INIS)

The conduits between intermediate heat exchangers, secondary pumps and steam generators are subject to important thermal stresses and expansions of large amplitude. The invention concerns a pipe which connects two fixed apparatus, ensuring the circulation of a fluid of which temperature is very high or low with regard to the ambient temperature. The conduit comprises three straight sections of which lengths are nearly the same, connected end to end and mounted such as the axis of any section is orthogonal with regard to the two other axes. This conduit allows to reduce stresses at their minimal value, more particularly thermal stresses, while reducing the conduit at its minimal length

1982-12-08

 
 
 
 
41

Electrical Conduit Distributes Weld Gas Evenly  

Science.gov (United States)

Purge-gas distributor, made from flexible electrical conduit by drilling small holes along its length, provides even gas flow for welding. Flexible conduit adjusts to accomodate almost any shape and is used for gas coverage in other applications that previously needed formed and drilled solid tubing.

Ambrisco, D. P.

1983-01-01

42

Transitional cell carcinoma in an ileal conduit.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Following cystectomy for transitional cell carcinoma a 63 year old woman developed recurrent tumours in the upper urinary tract and ileal conduit, suggesting that malignant transitional cells can auto-implant in ileal epithelium. This phenomenon has not been previously reported. We illustrate the value of retrograde urogram via an ileal conduit following cystectomy for cancer.

Curran, F. T.; Fuggle, W. J.

1986-01-01

43

Extra cardiac conduit Fontan procedure in 41 patients  

Directory of Open Access Journals (Sweden)

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.

Safarpour Gh

2007-07-01

44

Stochastic simulation of karst conduit networks  

Science.gov (United States)

Karst aquifers have very high spatial heterogeneity. Essentially, they comprise a system of pipes (i.e., the network of conduits) superimposed on rock porosity and on a network of stratigraphic surfaces and fractures. This heterogeneity strongly influences the hydraulic behavior of the karst and it must be reproduced in any realistic numerical model of the karst system that is used as input to flow and transport modeling. However, the directly observed karst conduits are only a small part of the complete karst conduit system and knowledge of the complete conduit geometry and topology remains spatially limited and uncertain. Thus, there is a special interest in the stochastic simulation of networks of conduits that can be combined with fracture and rock porosity models to provide a realistic numerical model of the karst system. Furthermore, the simulated model may be of interest per se and other uses could be envisaged. The purpose of this paper is to present an efficient method for conditional and non-conditional stochastic simulation of karst conduit networks. The method comprises two stages: generation of conduit geometry and generation of topology. The approach adopted is a combination of a resampling method for generating conduit geometries from templates and a modified diffusion-limited aggregation method for generating the network topology. The authors show that the 3D karst conduit networks generated by the proposed method are statistically similar to observed karst conduit networks or to a hypothesized network model. The statistical similarity is in the sense of reproducing the tortuosity index of conduits, the fractal dimension of the network, the direction rose of directions, the Z-histogram and Ripley's K-function of the bifurcation points (which differs from a random allocation of those bifurcation points). The proposed method (1) is very flexible, (2) incorporates any experimental data (conditioning information) and (3) can easily be modified when implemented in a hydraulic inverse modeling procedure. Several synthetic examples are given to illustrate the methodology and real conduit network data are used to generate simulated networks that mimic real geometries and topology.

Pardo-Igúzquiza, Eulogio; Dowd, Peter A.; Xu, Chaoshui; Durán-Valsero, Juan José

2012-01-01

45

Phase distribution in complex geometry conduits  

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-12-31

46

Microbial colonization of human ileal conduits.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Morphological and microbiological techniques were used to locate and identify the microorganisms that colonized the human ileal conduits in 17 different patients from 5 days after surgery up to as many as 16 years of service as a urine conduit. The ecological sequence of this colonization assumes some practical importance because the ascending growth of pathogenic organisms in this essentially open, unvalved urinary tract diversion system leads to the development of life-threatening pyeloneph...

Chan, R. C.; Reid, G.; Bruce, A. W.; Costerton, J. W.

1984-01-01

47

The interior coating of rectangular conduit structures  

International Nuclear Information System (INIS)

The problems associated with the interior coating of rectangular conduit structures are considered in the context of a concrete application example, viz. the interior goldplating of a rectangular, conduit-shaped antenna for 2.4 MW and 1.3 GHz used to heat plasma with radio waves. The antenna in question is the ASDEX transmitter of the Max Planck Institute for Plasma Physics (IPP) in Garching near Munich. (orig.)

1985-01-01

48

Structure of mono- and bimetallic heterogeneous catalysts based on noble metals obtained by means of fluid technology and metal-vapor synthesis  

Science.gov (United States)

Monometallic nanocomposites are obtained with the use of supercritical carbon dioxide (fluid technique) and metal-vapor synthesis (MVS), while bimetallic nanocomposites of Pt and Au noble metals and ?-Al2O3 oxide matrix are synthesized by a combination of these two methods. The structures, concentrations, and chemical states of metal atoms in composites are studied by means of small-angle X-ray scattering (SAXS), transparent electron microscopy (TEM), X-ray fluorescent analysis (XFA), and X-ray photoelectron spectroscopy (XPS). The neutral state of metal atoms in clusters is shown by XPS and their size distribution is found according to SAXS; as is shown, it is determined by the pore sizes of the oxide matrices and lies in the range of 1 to 50 nm. The obtained composites manifest themselves as effective catalysts in the oxidation of CO to CO2.

Said-Galiev, E. E.; Vasil'kov, A. Yu.; Nikolaev, A. Yu.; Lisitsyn, A. I.; Naumkin, A. V.; Volkov, I. O.; Abramchuk, S. S.; Lependina, O. L.; Khokhlov, A. R.; Shtykova, E. V.; Dembo, K. A.; Erkey, C.

2012-10-01

49

Long-term follow-up of patients with extracardiac valved conduits.  

Directory of Open Access Journals (Sweden)

Full Text Available Seventeen patients having extracardiac valved conduits placed between the right ventricle and pulmonary artery were followed for 7 to 87 months postoperatively (mean, 42 months, at the Heart Institute, Kenritsu Amagasaki Hospital, Japan. There were no late deaths in the study group. Three conduits have been replaced, all because of conduit stenosis. In two-dimensional echocardiographic examinations, commissural fusion and calcification of the valve were noted in 6 out of 16 xenograft valved conduits. Mechanical valve immobility was found in one patient. Neointimal peel of the dacron graft was noted in 6 out of 17 cases, and marked left ventricular deformity in the short axis view was found in 6. Late cardiac catheterization was done in 6 patients who were suspected of having valve failure and right ventricular hypertension by two-dimensional echocardiography. All 6 of these patients showed a high pressure gradient between the pulmonary artery and right ventricle and also had elevated right ventricular pressure. In conclusion, two-dimensional echocardiography is a simple, non-invasive and very accurate method for detecting conduit stenosis and valve failure. An echocardiographic series should be performed for a long-time postoperatively because obstructions of valved conduits may be progressive, and an operation may be advisable in order to prevent the development of advanced right ventricular hypertrophy and deterioration.

Sano,Shunji

1989-06-01

50

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-BDEs to Hexa-BDEs, respectively

2008-01-25

51

A case report of complication liked jejunal conduit syndrome induced by reconstruction of ileal conduit  

International Nuclear Information System (INIS)

The patient was a 77-year-old man who underwent radical cystectomy and ileal conduit urinary diversion due to bladder cancer in 1989. A stenosis of the right uretero-ileal anastomosis occurred in 1992, and of the left uretero-ileal anastomosis in 1999. These were treated with indwelling of a ureteral stent and percutaneous nephrostomy, respectively. He was admitted to our hospital for progressive renal dysfunction due to frequent pyelonephritis. We performed a reconstruction of the ileal conduit urinary diversion and after the removal of the bilateral ureteral stent he complained of nausea and general malaise. The laboratory data showed hyponatremia, hyperkalemia and azotemia, which were diagnosed as complication liked jejunal conduit syndrome. He was treated with hydration and salt supplementation. With regard to this case, we considered that a long ileal conduit close to the jejunum and renal dysfunction caused the complication liked jejunal conduit syndrome. Careful observation and follow-up laboratory examination should be performed if the patient has renal dysfunction and a long conduit near the jejunum is used for the ileal conduit. (author)

2004-03-01

52

Dispersive hydrodynamics in viscous fluid conduits.  

Science.gov (United States)

The evolution of the interface separating a conduit of light, viscous fluid rising buoyantly through a heavy, more viscous, exterior fluid at small Reynolds numbers is governed by the interplay between nonlinearity and dispersion. Previous authors have proposed an approximate model equation based on physical arguments, but a precise theoretical treatment for this two-fluid system with a free boundary is lacking. Here, a derivation of the interfacial equation via a multiple scales, perturbation technique is presented. Perturbations about a state of vertically uniform, laminar conduit flow are considered in the context of the Navier-Stokes equations with appropriate boundary conditions. The ratio of interior to exterior viscosities is the small parameter used in the asymptotic analysis, which leads systematically to a maximal balance between buoyancy driven, nonlinear self-steepening and viscous, interfacial stress induced, nonlinear dispersion. This results in a scalar, nonlinear partial differential equation describing large amplitude dynamics of the cross-sectional area of the intrusive fluid conduit, in agreement with previous derivations. The leading order behavior of the two-fluid system is completely characterized in terms of the interfacial dynamics. The regime of model validity is characterized and shown to agree with previous experimental studies. Viscous fluid conduits provide a robust setting for the study of nonlinear, dispersive wave phenomena. PMID:24032933

Lowman, N K; Hoefer, M A

2013-08-01

53

Dispersive hydrodynamics in viscous fluid conduits  

Science.gov (United States)

The evolution of the interface separating a conduit of light, viscous fluid rising buoyantly through a heavy, more viscous, exterior fluid at small Reynolds numbers is governed by the interplay between nonlinearity and dispersion. Previous authors have proposed an approximate model equation based on physical arguments, but a precise theoretical treatment for this two-fluid system with a free boundary is lacking. Here, a derivation of the interfacial equation via a multiple scales, perturbation technique is presented. Perturbations about a state of vertically uniform, laminar conduit flow are considered in the context of the Navier-Stokes equations with appropriate boundary conditions. The ratio of interior to exterior viscosities is the small parameter used in the asymptotic analysis, which leads systematically to a maximal balance between buoyancy driven, nonlinear self-steepening and viscous, interfacial stress induced, nonlinear dispersion. This results in a scalar, nonlinear partial differential equation describing large amplitude dynamics of the cross-sectional area of the intrusive fluid conduit, in agreement with previous derivations. The leading order behavior of the two-fluid system is completely characterized in terms of the interfacial dynamics. The regime of model validity is characterized and shown to agree with previous experimental studies. Viscous fluid conduits provide a robust setting for the study of nonlinear, dispersive wave phenomena.

Lowman, N. K.; Hoefer, M. A.

2013-08-01

54

Feed-thru conduit minimizes heat pickup  

Science.gov (United States)

Insulated feed-thru conduit minimizes heat pickup by a cryogenic fluid passing through the walls of a double high-vacuum chamber, and is capable of expansion and contraction with the walls of the chamber. It uses a bellows and rigid cylinder to provide a low-loss feed-thru for the cryogenic liquid.

Yager, S. P.

1967-01-01

55

Muscle recovery after repair of short and long peripheral nerve gaps using fibrin conduits.  

Science.gov (United States)

Peripheral nerve injuries with loss of nervous tissue are a significant clinical problem and are currently treated using autologous nerve transplants. To avoid the need for donor nerve, which results in additional morbidity such as loss of sensation and scarring, alternative bridging methods have been sought. Recently we showed that an artificial nerve conduit moulded from fibrin glue is biocompatible to nerve regeneration. In this present study, we have used the fibrin conduit or a nerve graft to bridge either a 10 mm or 20 mm sciatic nerve gap and analyzed the muscle recovery in adult rats after 16 weeks. The gastrocnemius muscle weights of the operated side were similar for both gap sizes when treated with nerve graft. In contrast, muscle weight was 48.32 ± 4.96% of the contra-lateral side for the 10 mm gap repaired with fibrin conduit but only 25.20 ± 2.50% for the 20 mm gap repaired with fibrin conduit. The morphology of the muscles in the nerve graft groups showed an intact, ordered structure, with the muscle fibers grouped in fascicles whereas the 20 mm nerve gap fibrin group had a more chaotic appearance. The mean area and diameter of fast type fibers in the 20 mm gap repaired with fibrin conduits were significantly (P<0.01) worse than those of the corresponding 10 mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. Furthermore, the 10 mm gaps repaired with either nerve graft or fibrin conduit showed similar muscle fiber size. These results indicate that the fibrin conduit can effectively treat short nerve gaps but further modification such as the inclusion of regenerative cells may be required to attain the outcomes of nerve graft for long gaps. PMID:21683768

Pettersson, Jonas; McGrath, Aleksandra; Kalbermatten, Daniel F; Novikova, Liudmila N; Wiberg, Mikael; Kingham, Paul J; Novikov, Lev N

2011-08-01

56

Xylem hydraulic conductivity related to conduit dimensions along chrysanthemum stems.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2001-01-01

57

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...2009-04-01 2009-04-01 false Conduit financing arrangements. 1.881-3...Foreign Corporations § 1.881-3 Conduit financing arrangements. (a) General...arrangement where such entities are acting as conduit entities. For purposes of this...

2009-04-01

58

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. (orig.)

2007-06-01

59

Dispersive Hydrodynamics in Viscous Fluid Conduits  

CERN Document Server

The evolution of the interface separating a conduit of light, viscous fluid rising buoyantly through a heavy, more viscous, exterior fluid at small Reynolds numbers is governed by the interplay between nonlinearity and dispersion. Previous authors have proposed an approximate model equation based on physical arguments, but a precise theoretical treatment for this two fluid system with a free boundary is lacking. Here, a derivation of the interfacial equation via a multiple scales, perturbation technique is presented. Perturbations about a state of vertically uniform, laminar conduit flow are considered in the context of the Navier-Stokes equations with appropriate boundary conditions. The ratio of interior to exterior viscosities is the small parameter used in the asymptotic analysis, which leads systematically to a maximal balance between buoyancy driven, nonlinear self-steepening and viscous, interfacial stress induced, nonlinear dispersion. This results in a scalar, nonlinear partial differential equation ...

Lowman, Nicholas K

2013-01-01

60

Secure E-Link For Jostle Conduit  

Directory of Open Access Journals (Sweden)

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.

Meenu Sahni

2011-01-01

 
 
 
 
61

Designing ideal conduits for peripheral nerve repair  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nerve tubes, guides, or conduits are a promising alternative for autologous nerve graft repair. The first biodegradable empty single lumen or hollow nerve tubes are currently available for clinical use and are being used mostly in the repair of small-diameter nerves with nerve defects of < 3 cm. These nerve tubes are made of different biomaterials using various fabrication techniques. As a result these tubes also differ in physical properties. In addition, several modifications to the common ...

Ruiter, Godard C. W.; Malessy, Martijn J. A.; Yaszemski, Michael J.; Windebank, Anthony J.; Spinner, Robert J.

2009-01-01

62

Liquid-Vapor Argon Isotope Fractionation from the Triple Point to the Critical Point : Mean Laplacian of the Intermolecular Potential in Liquid Argon  

DEFF Research Database (Denmark)

The statistical thermodynamic treatment of the equilibrium between a nonideal liquid mixture of isotopes and a vapor phase is extended to include isotope effects on the equation of state of the gas. The result is particularly simple when the isotopic partition functions in a given phase are compared at the same molar volume. The isotope fractionation factor α for 36Arâ??40Ar between liquid and vapor has been measured from the triple point to the critical temperature. The results are compared with previous vapor pressure data, which cover the range 84â??102°K. Although the agreement is within twice the statistical scatter of the present data, the present results for the lnα are systematically 5% lower than calculations from vapor pressure data. It is shown that T2 lnα is a linear function of (ρcâ??ρg), the density difference between the liquid and vapor, in the range 84â??120°K. The fractionation factor approaches zero at the critical temperature with a nonclassical critical index equal to 0.42±0.02.ã??â??2Ucã??/ρc in liquid argon is derived from the experimental fractionation data and calculations of ã??â??2Ugã??/ρg for a number of potential functions for gaseous argon.

Phillips, J. T.

1972-01-01

63

Biodegradable fibrin conduit promotes long-term regeneration after peripheral nerve injury in adult rats.  

Science.gov (United States)

Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. Biosynthetic neural conduits could be an alternative treatment strategy in such injuries. The present study investigates the long-term effects of a tubular fibrin conduit on neuronal regeneration, axonal sprouting and recovery of muscle weight following peripheral nerve injury and repair in adult rats. Sciatic axotomy was performed proximally in the thigh to create a 10-mm gap between the nerve stumps. The injury gap was bridged by using a 14-mm-long fibrin glue conduit, entubulating 2 mm of the nerve stump at each end. A reversed autologous nerve graft was used as a control. The regenerative response from sensory and motor neurones was evaluated following retrograde labelling with Fast Blue fluorescent tracer. In control experiments, at 16 weeks following peripheral nerve grafting, 5184 (±574 standard error of mean (SEM)) sensory dorsal root ganglion neurones and 1001 (±37 SEM) spinal motor neurones regenerated across the distal nerve-graft interface. The fibrin conduit promoted regeneration of 60% of sensory neurones and 52% of motor neurones when compared to the control group. The total number of myelinated axons in the distal nerve stump in the fibrin-conduit group reached 86% of the control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89% of the controls, respectively. The present results suggest that a tubular fibrin conduit can be used to promote neuronal regeneration following peripheral nerve injury. PMID:20005193

Pettersson, Jonas; Kalbermatten, Daniel; McGrath, Aleksandra; Novikova, Liudmila N

2010-11-01

64

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

1995-05-06

65

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

Science.gov (United States)

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.

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

2007-01-01

66

System and method measuring fluid flow in a conduit  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.

Ortiz, Marcos German (Idaho Falls, ID); Kidd, Terrel G. (Blackfoot, ID)

1999-01-01

67

Parastomal Hernia as a Risk Factor for Ileal Conduit Fistulae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 stran...

Skinner, Thomas A. A.; Norman, Richard W.

2011-01-01

68

Ileal conduit stomal variceal bleeding managed by endovascular embolization  

Directory of Open Access Journals (Sweden)

Full Text Available Ileal conduit stomal varices are rare, and may result in bleeding. The standard treatment modality for management of this type of hemorrhage has not been established. We present the case of a 70-year-old woman with progressive ileal conduit stomal variceal bleeding which was successfully managed by endovascular embolization via the transjugular transhepatic approach. In conclusion, transjugular transhepatic endovascular embolization is a good choice in patients with ileal conduit stomal variceal bleeding who have failed conservative therapy.

Deng-Hua Yao

2013-01-01

69

Ileal conduit stomal variceal bleeding managed by endovascular embolization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ileal conduit stomal varices are rare, and may result in bleeding. The standard treatment modality for management of this type of hemorrhage has not been established. We present the case of a 70-year-old woman with progressive ileal conduit stomal variceal bleeding which was successfully managed by endovascular embolization via the transjugular transhepatic approach. In conclusion, transjugular transhepatic endovascular embolization is a good choice in patients with ileal conduit stomal varic...

Deng-Hua Yao; Xue-Feng Luo; Biao Zhou; Xiao Li

2013-01-01

70

Parastomal Hernia as a Risk Factor for Ileal Conduit Fistulae  

Directory of Open Access Journals (Sweden)

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.

Thomas A. A Skinner

2011-07-01

71

Further Development, Support and Enhancement of CONDUIT  

Science.gov (United States)

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.

Veronica, Moldoveanu; Levine, William S.

1999-01-01

72

Understanding Metaphors for Writing: In Defense of the Conduit Metaphor.  

Science.gov (United States)

Considers how the Conduit Metaphor of language and communication has been roundly condemned by language scholars, including scholars in rhetoric and composition. Notes that it is time to reevaluate its importance and value. Notes that the Conduit Metaphor combines with the metaphor Language Is Power to form a prudentially applied ethical measure…

Eubanks, Philip

2001-01-01

73

26 CFR 1.58-2 - General rules for conduit entities; partnerships and partners.  

Science.gov (United States)

...2009-04-01 false General rules for conduit entities; partnerships and partners...Regulations § 1.58-2 General rules for conduit entities; partnerships and partners. (a) General rules for conduit entities. Sections...

2009-04-01

74

Spotlight on CERN : Le code de conduite  

CERN Multimedia

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.

CERN Video Productions

2010-01-01

75

Effect of Ti conduit on the critical current in (Nb,Ti)(sub 3)Sn cable-in-conduit conductors.  

Science.gov (United States)

The effect of titanium conduit on the critical current in (Nb,Ti)(sub 3)Sn cable-in-conduit conductors was investigated to obtain a high performance conductor which would be applied to large superconducting magnets such as those for fusion machines. Titan...

Y. Wadayama T. Ando H. Nakajima M. Nishi Y. Yasukawa

1993-01-01

76

Conduits and dike distribution analysis in San Rafael Swell, Utah  

Science.gov (United States)

Volcanic fields generally consist of scattered monogenetic volcanoes, such as cinder cones and maars. The temporal and spatial distribution of monogenetic volcanoes and probability of future activity within volcanic fields is studied with the goals of understanding the origins of these volcano groups, and forecasting potential future volcanic hazards. The subsurface magmatic plumbing systems associated with volcanic fields, however, are rarely observed or studied. Therefore, we investigated a highly eroded and exposed magmatic plumbing system on the San Rafael Swell (UT) that consists of dikes, volcano conduits and sills. San Rafael Swell is part of the Colorado Plateau and is located east of the Rocky Mountain seismic belt and the Basin and Range. The overburden thickness at the time of mafic magma intrusion (Pliocene; ca. 4 Ma) into Jurassic sandstone is estimated to be ~800 m based on paleotopographical reconstructions. Based on a geologic map by P. Delaney and colleagues, and new field research, a total of 63 conduits are mapped in this former volcanic field. The conduits each reveal features of root zone and / or lower diatremes, including rapid dike expansion, peperite and brecciated intrusive and host rocks. Recrystallized baked zone of host rock is also observed around many conduits. Most conduits are basaltic or shonkinitic with thickness of >10 m and associated with feeder dikes intruded along N-S trend joints in the host rock, whereas two conduits are syenitic and suggesting development from underlying cognate sills. Conduit distribution, which is analyzed by a kernel function method with elliptical bandwidth, illustrates a N-S elongate higher conduit density area regardless of the azimuth of closely distributed conduits alignment (nearest neighbor distance concordant with the high dike density area. Especially, the distribution of conduits is not random with respect to the dike distribution with greater than 99% confidence on the basis of the Kolmogorov-Smirnov test. On the other hand, dike density at each conduits location also suggests that there is no threshold of dike density for conduit formation. In other words, conduits may be possible to develop from even short mapped dikes in low dike density areas. These results show effectiveness of studying volcanic vent distribution to infer the size of magmatic system below volcanic fields and highlight the uncertainty of forecasting the location of new monogenetic volcanoes in active fields, which may be associated with a single dike intrusion.

Kiyosugi, K.; Connor, C.; Wetmore, P. H.; Ferwerda, B. P.; Germa, A.

2011-12-01

77

Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.  

Science.gov (United States)

Fibre structures represent a potential class of materials for the formation of synthetic nerve conduits due to their biomimicking architecture. Although the advantages of fibres in enhancing nerve regeneration have been demonstrated, in vivo evaluation of fibre size effect on nerve regeneration remains limited. In this study, we analyzed the effects of fibre diameter of electrospun conduits on peripheral nerve regeneration across a 15-mm critical defect gap in a rat sciatic nerve injury model. By using an electrospinning technique, fibrous conduits comprised of aligned electrospun poly (?-caprolactone) (PCL) microfibers (981?±?83 nm, Microfiber) or nanofibers (251?±?32 nm, Nanofiber) were obtained. At three months post implantation, axons regenerated across the defect gap in all animals that received fibrous conduits. In contrast, complete nerve regeneration was not observed in the control group that received empty, non-porous PCL film conduits (Film). Nanofiber conduits resulted in significantly higher total number of myelinated axons and thicker myelin sheaths compared to Microfiber and Film conduits. Retrograde labeling revealed a significant increase in number of regenerated dorsal root ganglion sensory neurons in the presence of Nanofiber conduits (1.93 ± 0.71 × 10(3) vs. 0.98 ± 0.30 × 10(3) in Microfiber, p?conduit group compared to the Microfiber group. This study demonstrated the impact of fibre size on peripheral nerve regeneration. These results could provide useful insights for future nerve guide designs. PMID:22700359

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

2014-05-01

78

Influence of the Hydrogeological Setting on Englacial Conduit Morphology  

Science.gov (United States)

Glaciological ideas about the character and evolution of englacial drainage systems have been deeply influenced by the theoretical model developed by Shreve (1972). The Shreve model is based on three main assumptions: (1) englacial drainage is in steady state; (2) englacial water will flow along the steepest hydraulic gradient within the glacier; and (3) pressure head equals the pressure of the surrounding ice minus a small component due to melting of the walls. The Shreve model has been widely adopted as a fundamental component of englacial drainage theory. There is no evidence, however, that the model provides a realistic picture of actual glacier drainage systems. To evaluate Shreve theory, we used speleological techniques to directly survey englacial conduits. We mapped a total of 8.5 km of passage in 45 distinct englacial conduits in temperate, polythermal, cold-based and debris-covered glaciers between 2005 and 2008. New information reported here is supplemented by published data on 40 other englacial conduits located worldwide and investigated to ice depths of 200 m using speleological techniques. In all cases, englacial conduits consisted of a single unbraching conduit. Englacial conduit morphologies were found to be intimately linked to the orientation of a glacier's principal stresses or the presence of pre-existing lines of high hydraulic conductivity. If a sufficient supply of water is available, hydrofracturing forms vertical conduits in zones of longitudinal extension and subhorizontal conduits where longitudinal stresses are compressive. On unfractured glacier surfaces, relatively shallow subhorizontal conduits with migrating nickpoints form by cut- and-closure provided channel incision is significantly faster than surface lowering. Conduits can also form along permeable debris-filled crevasse traces that connect supraglacial lake basins of different potential. Only conduits formed by extensional hydrofracture were found to be connected to glacier beds. Our results suggest that a Shreve-type englacial drainage system probably doesn"t exist and implies that englacial conduits can only penetrate through thick ice to recharge the bed of the Greenland Ice Sheet where supraglacial water bodies either intersect, or are advected through, zones of acceleration.

Gulley, J. D.; Benn, D. I.

2008-12-01

79

Outcome of deceased donor renal transplantation in patients with an ileal conduit.  

Science.gov (United States)

Renal transplantation in recipients with an ileal conduit is uncommon and occasionally controversial as it has been associated with high morbidity and mortality rates. We report on 17 patients with an ileal conduit who received a deceased donor renal transplant at our institution between January 1986 and December 2012. We retrospectively reviewed their allograft and surgical outcome. There were four mortalities at five, five, 39, and 66 months post-transplant. Sixteen of 17 grafts functioned immediately; one patient had primary non-function secondary to vascular thrombosis. Thirteen of 17 (76.5%) grafts were functioning at a mean follow-up period of 105 months. The mean serum creatinine at follow-up was 111 ?M (±38.62). Five patients had seven episodes of urosepsis requiring hospital admission, and five patients received treatment for renal stone disease. We conclude that given improvements in immunosuppression, surgical technique, infection treatment, and selection criteria, we believe that renal transplantation in the patient with an ileal conduit yields excellent graft survival, although there is a high morbidity rate in this cohort of patients in the long term. PMID:24476501

McLoughlin, Louise C; Davis, Niall F; Dowling, Catherine M; Power, Richard E; Mohan, Ponusamy; Hickey, David P; Smyth, Gordon P; Eng, Molly M P; Little, Dilly M

2014-03-01

80

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 certain surgical factors that render other urinary diversion methods more difficult carry more postoperative morbidity and mortality or both. (author)

2008-01-01

 
 
 
 
81

Vapor generator  

International Nuclear Information System (INIS)

The object of the present invention is the provision of an improved vapor generator for use with a gas-cooled reactor in an electrical power generating facility. The vapor generator is particularly suited for use in a substantially cylindrical cavity in a pressure vessel and the length of tubing used in unheated sections and in expansion zones is minimized. (UK)

1976-01-01

82

Reduction of hotspot temperature in cable-in-conduit conductors  

International Nuclear Information System (INIS)

The hotspot temperature is one of the most important design criteria for cable-in-conduit conductors. In general, the amount of copper, as a stabilizer, in a bundle is determined by the allowable hotspot temperature, which contradicts to have a high current density in the conductor. In this study, a conductor with a copper-clad conduit is proposed. Current sharing between the bundle and copper cladding can reduce the current in the bundle during a quench. This reduces the hotspot temperature. The effect of copper cladding is analyzed for simulated conductors using zero-dimensional heat-balance equations. The simulated conductors have a circular cross-section with a diameter of 50 mm and a 1-mm-thick copper cladding outside a stainless-steel conduit. The analyses demonstrate the possibility of reducing the hotspot temperature even though high thermal resistance exists between the bundle and conduit. (author)

2004-04-01

83

Stability of power-law cable-in-conduit superconductors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The stability properties of cable-in-conduit superconductors with a power-law voltage-current characteristic are investigated using a previously developed model description for the take-off properties of these conductors.

Anghel, A.

2004-01-01

84

Current understanding of phase separation mechanisms in branching conduits  

International Nuclear Information System (INIS)

This paper presents a summary of the state-of-the-art in our understanding of phase separation in branching conduits. The currently existing data base and analytical models are reviewed, and the ''lessons learned'' are summarized. It is shown that no completely satisfactory model exists for the prediction of phase separation in conduits of untested geometry and/or operating conditions. Nevertheless, based on our current understanding, an interim model is proposed. (orig.)

1986-08-01

85

Conduit Magma Storage during the 800 BP Quilotoa Eruption, Ecuador  

Science.gov (United States)

The 800 BP eruption of Quilotoa produced two large ignimbrites, U1 (~5.8 km3 DRE) and U3 (~1.8 km3 DRE). These eruptions were separated by a series of much smaller eruptions over one to several weeks, as inferred from 1) the intercalation of secondary pyroclastic and debris flow deposits between U1 and U3, 2) deposits from phreatic explosions from the U1 ignimbrite surface, 3) oxidation of the upper 2 m of U1, and 4) a lack of erosion of the U1 surface. Why did the main phase of the eruption (U1) stall when eruptable magma was available? How did explosive activity stop and restart? We address these questions by examining deposits (U2) emplaced during the 'hiatus' that provide information on the conditions in the conduit and vent area between explosive episodes. The lowest sub-unit, U2a, forms a series of pumiceous surge deposits found only within 5 km of the crater rim. U2b is a vitric-poor, crystal- and lithic-rich fall deposit distributed to about 15 km from the crater. U2c is a thin gray fine ash containing 2-5-mm-diameter rhyolite lapilli that is present within 6 km of the vent. Similar lapilli also occur in the lowermost few centimeters of U3 and appear to be from a dome that exploded as the new magma arrived at the surface; their presence as small ballistic fragments ties U2c to lowermost U3 in time. U2a appears to have been emplaced by episodic surges and weak fallout plumes, whereas U2b and U2c were deposited from a series of sustained eruption columns. Moreover, the lack of U2b grain-size variation with distance suggests that the grain size was determined at the vent, not by transport. FTIR analysis of CO2 and H2O in melt inclusions (MIs) indicates that a deep magma chamber (>400 MPa; ~12 km) fed U1. U2a and U2b MIs plot along vapor isopleths, suggesting equilibration at pressures to about 300 MPa as CO2 outgassed. U2b MIs have lower CO2 than U2a, perhaps indicating continued degassing during the 'hiatus'. MIs from the lower few centimeters of U3 lie along a ~130 MPa isobar, suggesting shallow magma storage during the hiatus. Using these data, we hypothesize that the eruption of U1 ended when conduit constriction above 4 km choked the ascent of magma. Continued open-system degassing of the magma column produced the U2 MI compositions and led to milling and acid etching of the crystal-rich material, eliminating much of the glass. Periodic explosions during dome formation produced U2a. Continued magma ascent caused increased gas emissions that ejected U2b as a continuous column. As the U3 magma reached the surface, it blew out the dome prior to eruption of new deeper magma. The high pressures in MIs in plagioclase crystals in U1 and lack of any evidence for mafic magma supply imply the shallow dacitic system is fed by evolved magmas that differentiated at high pressure.

Ort, M. H.; Cashman, K. V.; Di Muro, A.; Best, J. A.; Rosi, M.; Mothes, P. A.; Bustillos, J.

2013-12-01

86

CONDUIT: A New Multidisciplinary Integration Environment for Flight Control Development  

Science.gov (United States)

A state-of-the-art computational facility for aircraft flight control design, evaluation, and integration called CONDUIT (Control Designer's Unified Interface) has been developed. This paper describes the CONDUIT tool and case study applications to complex rotary- and fixed-wing fly-by-wire flight control problems. Control system analysis and design optimization methods are presented, including definition of design specifications and system models within CONDUIT, and the multi-objective function optimization (CONSOL-OPTCAD) used to tune the selected design parameters. Design examples are based on flight test programs for which extensive data are available for validation. CONDUIT is used to analyze baseline control laws against pertinent military handling qualities and control system specifications. In both case studies, CONDUIT successfully exploits trade-offs between forward loop and feedback dynamics to significantly improve the expected handling, qualities and minimize the required actuator authority. The CONDUIT system provides a new environment for integrated control system analysis and design, and has potential for significantly reducing the time and cost of control system flight test optimization.

Tischler, Mark B.; Colbourne, Jason D.; Morel, Mark R.; Biezad, Daniel J.; Levine, William S.; Moldoveanu, Veronica

1997-01-01

87

Temperature limited heater with a conduit substantially electrically isolated from the formation  

Energy Technology Data Exchange (ETDEWEB)

A system for heating a hydrocarbon containing formation is described. A conduit may be located in an opening in the formation. The conduit includes ferromagnetic material. An electrical conductor is positioned inside the conduit, and is electrically coupled to the conduit at or near an end portion of the conduit so that the electrical conductor and the conduit are electrically coupled in series. Electrical current flows in the electrical conductor in a substantially opposite direction to electrical current flow in the conduit during application of electrical current to the system. The flow of electrons is substantially confined to the inside of the conduit by the electromagnetic field generated from electrical current flow in the electrical conductor so that the outside surface of the conduit is at or near substantially zero potential at 25.degree. C. The conduit may generate heat and heat the formation during application of electrical current.

Vinegar, Harold J. (Bellaire, TX); Sandberg, Chester Ledlie (Palo Alto, CA)

2009-07-14

88

Injection control device for subterranean well conduit  

Energy Technology Data Exchange (ETDEWEB)

An injection control valve is described for treating a production formation of a subterranean well comprising packer means settable adjacent to the formation to be treated; a hollow mandrel extending upwardly from the packer means; an upwardly facing abutment surface on the packer means located within the mandrel; a hollow valve housing; slip joint means connecting the lower end of the valve housing to the upper end of the mandrel; means for connecting the upper end of the valve housing to a tubing string; a support rod axially traversing the valve housing and the mandrel and supported by the upwardly facing abutment surface. Also included is a description of the valving mechanism.

Ross, R.J.; Klumpyan, J.N.

1987-05-05

89

Phase distribution phenomena in triangular conduits  

International Nuclear Information System (INIS)

Two-phase (air/water) measurements of phase distribution phenomena were made in a triangular test section. These measurements included the lateral void fraction distribution and the velocity profile of the liquid phase. In addition, measurements of the development length of the two-phase mixture were made. It was found that substantial lateral void drift occurred, with the vapor phase collecting in the more open, high velocity, region of the test section. A three-dimensional finite element computer code, FEMOTH, was developed in order to study multidimensional phase distribution phenomena and the turbulent structure of fully developed turbulent two-phase flow. The FEMOTH code was based on a simplified model of two-phase flow and was tested against the experimental data. Sensitivity studies were performed through numerical experiments using the FEMOTH code. The FEMOTH code predicted the observed data trends, but more work is needed before quantitative predictions are possible

1986-01-01

90

Interactions of large amplitude solitary waves in viscous fluid conduits  

CERN Multimedia

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...

Lowman, Nicholas K; El, Gennady A

2013-01-01

91

Regenerative effect of adipose tissue-derived stem cells transplantation using nerve conduit therapy on sciatic nerve injury in rats.  

Science.gov (United States)

This study proposed a biodegradable GGT nerve conduit containing genipin crosslinked gelatin annexed with tricalcium phosphate (TCP) ceramic particles for the regeneration of peripheral nerves. Cytotoxicity tests revealed that GGT-extracts were non-toxic and promoted proliferation and neuronal differentiation in the induction of stem cells (i-ASCs) derived from adipose tissue. Furthermore, the study confirmed the effectiveness of a GGT/i-ASCs nerve conduit as a guidance channel in the repair of a 10-mm gap in the sciatic nerve of rats. At eight weeks post-implantation, walking track analysis showed a significantly higher sciatic function index (SFI) (P?mean recovery index of compound muscle action potential (CMAP) differed significantly between GGT/i-ASCs and autograft groups (P?conduits were similar to those of the autografts. These promising results achieved through a combination of regenerative cells and GGT nerve conduits suggest the potential value in the future development of clinical applications for the treatment of peripheral nerve injury. PMID:22552954

Liu, Bai-Shuan; Yang, Yi-Chin; Shen, Chiung-Chyi

2014-05-01

92

Development of conduits for the ITER central solenoid conductor  

International Nuclear Information System (INIS)

The Japan Atomic Energy Agency has developed a JK2LB conduit for the Nb3Sn conductor of the ITER central solenoid (CS). Mechanical requirements for the CS conductor conduit are a 0.2% yield strength of more than 900 MPa and a fracture toughness KIC (J) of more than 130 MPa ?m after a compaction and aging heat treatment (650degC, 240 hours). In a previous work, it was shown that an aged JK2LB conduit has high strength and sufficient fracture toughness enough to satisfy the requirements. As the next step, work was performed to determine the specifications of the JK2LB conduit taking into account of cold work, including compaction and winding, and to simplify its fabrication process. To simulate the cold work effect with cold work of 10% and aging, mechanical tests were performed at 4.2 K on laboratory-scale (20-30 kg) ingot samples at 4.2 K. It was found that the sum of carbon and nitrogen content should be in the range from 0.11% to 0.18% to achieve the ITER mechanical requirements. To obtain a grain-sized of conduit as well as that of a small ingot sample, the appropriate solution heat-treatment temperature and holding time were studied. In order to simplify the billet production process, we confirmed the internal metallurgical qualities of a JK2LB-cast ingot. Since significant segregation was not observed, it was possible to exclude the electroslag remelting process. Based on the above achievements, full-size JK2LB conduits that satisfy the ITER mechanical requirements were fabricated. (author)

2008-06-01

93

[The preparation and evaluation of tissue inducible nerve guide conduit].  

Science.gov (United States)

The objective of this research was to fabricate a novel tissue inducible nerve guide conduit, and to evaluate its biologic property. The microspheres were prepared with chitosan that encapsulated ligustrazine. The drug release of the chitosan microspheres was detected with application of the controlled release method in vitro. Chitosan microspheres were mixed with collagen to fabricate the tissue inducible nerve conduit, which were crosslinked with 2% genipin for 24h. Mechanical properties of the nerve guide conduit samples, including maximum load and breaking load, were measured using an Instron Series IX Automated Materials Testing System. The flexibility of the nerve guide conduit was determined with the texture evaluation instrument. Different methods, such as scanning electron microscope (SEM), light microscope (LMS) and immunofluorescence were used to analyze the spatial structure of the nerve guide conduit, the distribution of the microspheres, the state of the nerve duct combined with mesenchymal stem cells (MSCs), and the effect of the ligustrazine that released from chitosan microsphere on MSCs differentiation into nerve cells, respectively. The results showed that the chitosan microspheres had better releasing effect. The mechanical properties resultant nerve guide conduit were determined. The maximum load and breaking load of the genipin crosslinked samples were significantly higher than that observed with the non-crosslinkers, increasing to (0.76 +/- 0.15) N and (0.69 +/- 0.17) N from (0.23 +/- 0.09) N and (0.20 +/- 0.12) N for the non-crosslinkers (P crosslinked and crosslinked by genipin were(58.62 +/- 7.59) mg and (9.23 +/- 2.47) mg, respec- tively. This had a statistical significance (P crosslinking samples, the microspheres were uniformly distributed on the surface of scaffold, the ligustrazine that released from the chitosan microspheres could promote MSCs to express NSE and MAP2 that were the relevant marker molecule of nerve cells. The nerve guide conduit is combined with MSCs, which promote MSCs proliferation and NSE expression by the ligustrazine that released from the chitosan microspheres. The conduit has better biological compatibility and tissue inducible function. PMID:22616182

Zhao, Hongbin; Liu, Xingyan; Ge, Baofeng; Guo, Chao; Zhen, Ping

2012-04-01

94

Single-friction-surface triboelectric generator with human body conduit  

Science.gov (United States)

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/cm2. 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.

Meng, Bo; Cheng, Xiaoliang; Zhang, Xiaosheng; Han, Mengdi; Liu, Wen; Zhang, Haixia

2014-03-01

95

Early experiences and in-hospital results with a novel off-pump apico-aortic conduit†  

Science.gov (United States)

OBJECTIVES To offer surgical treatment in patients with aortic valve stenosis and contraindications for aortic valve replacement (e.g. ostial encroachment and previous mitral valve replacement). The aim of this study was to prove the feasibility and efficacy of this novel innovative off-pump apico-aortic conduit technique. METHODS The bipartite conduit consists of an 18-mm prosthetic tube graft containing a stentless porcine aortic valve as well as a flexible semi-rigid and curved ventricular connector. Via left anterior lateral thoracotomy, the valved conduit is sutured to the descending aorta. The left ventricular connector is implanted with a gun-like applicator into the apex without cardiopulmonary bypass and with minimal blood loss. RESULTS Between March and December 2011, 7 patients (5 females/2 males) with a mean age of 82 (79–89 years) were operated on. The mean logistic EuroSCORE I was 36.4 ± 23.7 (median 36.7%). The mean ejection fraction was 37 (25–65%) and the mean preoperative transaortic gradient was 38 (22–53 mmHg). Three patients had previous mechanical mitral valve replacement, 1 had a porcelain aorta and 3 had unfavourable distances between the aortic annulus and ostia (ostial encroachment). Implantation was uneventful in all patients, with need for limited cardiopulmonary bypass in only 1 patient. Postoperative mean transaortic gradient was 14 (11–25 mmHg). Approximately 70% of stroke volume was bypassed as measured in postoperative magnetic resonance. One patient died in hospital due to respiratory failure. New York Heart Association class in the other patients diminished from 3.6 to 1.6. No rhythmic disturbances or heart block were encountered. CONCLUSIONS With this novel conduit, we observed excellent haemodynamic results. We feel that this additional surgical approach to aortic stenosis in elderly, high-risk patients can augment conventional on-pump and interventional treatments of aortic stenosis.

Reuthebuch, Oliver; Fassl, Jens; Brown, John; Grapow, Martin; Eckstein, Friedrich

2013-01-01

96

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

Science.gov (United States)

Lake Michigan diversion accounting is the process used by the U. S. Army Corps of Engineers to quantify the amount of water that is diverted from the Lake Michigan watershed into the Illinois and Mississippi River Basins. A network of streamgages within the Chicago area waterway system monitor tributary river flows and the major river flow on the Chicago Sanitary and Ship Canal near Lemont as one of the instrumental tools used for Lake Michigan diversion accounting. The mean annual discharges recorded by these streamgages are used as additions or deductions to the mean annual discharge recorded by the main stream gaging station currently used in the Lake Michigan diversion accounting process, which is the Chicago Sanitary and Ship Canal near Lemont, Illinois (station number 05536890). A new stream gaging station, Summit Conduit near Summit, Illinois (station number 414757087490401), was installed on September 23, 2010, for the purpose of monitoring stage, velocity, and discharge through the Summit Conduit for the U.S. Army Corps of Engineers in accordance with Lake Michigan diversion accounting. Summit Conduit conveys flow from a small part of the lower Des Plaines River watershed underneath the Des Plaines River directly into the Chicago Sanitary and Ship Canal. Because the Summit Conduit discharges into the Chicago Sanitary and Ship Canal upstream from the stream gaging station at Lemont, Illinois, but does not contain flow diverted from the Lake Michigan watershed, it is considered a flow deduction to the discharge measured by the Lemont stream gaging station in the Lake Michigan diversion accounting process. This report offers a technical summary of the techniques and methods used for the collection and computation of the stage, velocity, and discharge data at the Summit Conduit near Summit, Illinois stream gaging station for the 2011 and 2012 Water Years. The stream gaging station Summit Conduit near Summit, Illinois (station number 414757087490401) is an example of a nonstandard stream gage. Traditional methods of equating stage to discharge historically were not effective. Examples of the nonstandard conditions include the converging tributary flows directly upstream of the gage; the trash rack and walkway near the opening of the conduit introducing turbulence and occasionally entraining air bubbles into the flow; debris within the conduit creating conditions of variable backwater and the constant influx of smaller debris that escapes the trash rack and catches or settles in the conduit and on the equipment. An acoustic Doppler velocity meter was installed to measure stage and velocity to compute discharge. The stage is used to calculate area based the stage-area rating. The index-velocity from the acoustic Doppler velocity meter is applied to the velocity-velocity rating and the product of the two rated values is a rated discharge by the index-velocity method. Nonstandard site conditions prevalent at the Summit Conduit stream gaging station generally are overcome through the index-velocity method. Despite the difficulties in gaging and measurements, improvements continue to be made in data collection, transmission, and measurements. Efforts to improve the site and to improve the ratings continue to improve the quality and quantity of the data available for Lake Michigan diversion accounting.

Johnson, Kevin K.; Goodwin, Greg E.

2013-01-01

97

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

Science.gov (United States)

...to file Real Estate Mortgage Investment Conduit (REMIC) income tax return. 1.6081-7...to file Real Estate Mortgage Investment Conduit (REMIC) income tax return. (a... A Real Estate Mortgage Investment Conduit (REMIC) required to file an income...

2010-04-01

98

77 FR 102 - Turnbull Hydro LLC; Notice of Application Accepted for Filing for Exemption for a Small Conduit...  

Science.gov (United States)

...Accepted for Filing for Exemption for a Small Conduit Hydroelectric Facility and Soliciting...public inspection: a. Application Type: Conduit Exemption. b. Project No: 14294-000...Description of Request: The proposed small conduit hydroelectric project would consist...

2012-01-03

99

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

Science.gov (United States)

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

Kang, Jianhong; Xu, Mingyu

2009-04-01

100

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

2003-10-01

 
 
 
 
101

EMP Testing of Buried Conduits, The Pulsed Dipole and Pulsed Transmission Line.  

Science.gov (United States)

Buried conduit systems form an integral part of the EMP shielding in large hardened missile systems such as SAFEGUARD to protect the communications, control, and power cabling from NEMP effects. To initially verify conduit system hardness and to ensure th...

E. Seijo F. J. Agee H. A. Roberts

1975-01-01

102

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

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

2011-01-01

103

Morphometric analysis of three-dimensional networks of karst conduits  

Science.gov (United States)

The main idiosyncrasy of a typical karst system is the presence of a three-dimensional network of conduits behaving as drains in the system and being responsible of both the quick response of karst springs to rainfall events and the complex distribution of solutes in the system. A morphometric analysis of the three-dimensional geometry of conduits provides quantitative measures that can be used in a range of applications. These morphometric parameters can be used as descriptors of the underground geomorphology, they provide information on speleogenesis processes, they can be correlated with karst denudation ratios, they can be used to control the simulation of realistic stochastic karst networks of conduits, and they can be correlated with hydrogeologic behaviour of the karst system. The main purpose of this paper is to define, describe and illustrate a range of morphometric indexes and morphometric functions that can be calculated nowadays because the availability of three-dimensional topographies provided by speleological work and the availability of the computational and graphical power provided by modern computers. Some of the morphometric parameters describe the existence of preferential directions of karstification, others describe the kartification along the vertical and the possible presence of inception horizons. Other indexes describe the shape complexity of the karstic network, whilst other indexes describe spatial variability of the conduit geometry, and other parameters give account of the connectivity of the three-dimensional network. The morphometric analysis is illustrated with a three-dimensional karstic network in Southern France.

Pardo-Iguzquiza, Eulogio; Durán-Valsero, Juan J.; Rodríguez-Galiano, Victor

2011-09-01

104

Combined physical and chemical nonequilibrium transport model for solution conduits.  

Science.gov (United States)

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. PMID:24292209

Field, Malcolm S; Leij, Feike J

2014-02-01

105

Combined physical and chemical nonequilibrium transport model for solution conduits  

Science.gov (United States)

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.

Field, Malcolm S.; Leij, Feike J.

2014-02-01

106

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)

1990-01-01

107

Synergistic effects of micropatterned biodegradable conduits and Schwann cells on sciatic nerve regeneration  

Science.gov (United States)

This paper describes a novel biodegradable conduit that provides a combination of physical, chemical and biological cues at the cellular level to facilitate peripheral nerve regeneration. The conduit consists of a porous poly(D,L-lactic acid) (PDLLA) tubular support structure with a micropatterned inner lumen. Schwann cells were pre-seeded into the lumen to provide additional trophic support. Conduits with micropatterned inner lumens pre-seeded with Schwann cells (MS) were fabricated and compared with three types of conduits used as controls: M (conduits with micropatterned inner lumens without pre-seeded Schwann cells), NS (conduits without micropatterned inner lumens pre-seeded with Schwann cells) and N (conduits without micropatterned inner lumens, without pre-seeded Schwann cells). The conduits were implanted in rats with 1 cm sciatic nerve transections and the regeneration and functional recovery were compared in the four different cases. The number or size of regenerated axons did not vary significantly among the different conduits. The time of recovery, and the sciatic function index, however, were significantly enhanced using the MS conduits, based on qualitative observations as well as quantitative measurements using walking track analysis. This demonstrates that biodegradable micropatterned conduits pre-seeded with Schwann cells that provide a combination of physical, chemical and biological guidance cues for regenerating axons at the cellular level offer a better alternative for repairing sciatic nerve transactions than conventional biodegradable conduits.

Rutkowski, Gregory E.; Miller, Cheryl A.; Jeftinija, Srdija; Mallapragada, Surya K.

2004-09-01

108

Structural control of englacial conduits in the temperate Matanuska Glacier, Alaska, USA  

Science.gov (United States)

Fourteen englacial conduits were mapped within 2 km of the terminus of the temperate Matanuska Glacier, Alaska, USA, to ice depths of 65 m using speleological techniques. Detailed three-dimensional maps of the conduits were made over 3 years to characterize conduit relationships with glacier structural features and to track conduit evolution through time. All conduits consisted of single unbranching passages that followed fractures in the ice. All conduits were either too constricted to continue or became water-filled at their deepest explored point and were not able to be followed to the glacier bed. Conduit morphology varied systematically with the orientation of the glacier principal stresses, allowing them to be categorized into two broad classes. The first class of conduits were formed by hydrostatic crevasse penetration where a large supraglacial stream intersected longitudinal crevasses. These conduits plunged toward the glacier bed at angles of 30-40°. The second class of conduits formed where smaller streams sank into the glacier on shear crevasses. Many of these conduits changed direction dramatically where they intersected transverse crevasses at depth. These results suggest that the conduits observed in this study formed along fractures and, over their surveyed length, were not affected by gradients in ice overburden pressure.

Gulley, Jason

109

Air Demand and Conduit Pressures Stillhouse Hollow Dam, Lampasas River, Texas.  

Science.gov (United States)

Tests were conducted to provide data on prototype conduit air demand during high water discharges and to determine conduit losses at high Reynolds numbers (10 to the 7th power). The latter information was used to compute the conduit roughness coefficient ...

E. D. Hart

1988-01-01

110

Bubble Rise and Break-Up in Volcanic Conduits  

Science.gov (United States)

The continual passive degassing occurring at open-vent mafic volcanoes is often punctuated by bursts of active degassing. The latter are generally thought to be the result of slug flow: large, conduit-filling bubbles periodically rising up the feeder conduit and bursting at the magma-air interface. Existing models of volcanic degassing systems make the simplifying assumption that the conduit is cylindrical; however, while this may be true at shallow levels, a flaring probably connects it to a dyke-like geometry at depth. The overall goal of this research is to assess the influence of conduit geometry on the speed and stability of bubbles rising in open-vent systems, and ultimately to devise a model to infer conduit shape from emerging bubbles size. In order to do that an analogue experimental approach was used. All of the experiments were two-phase (melt+volatiles); the analogue materials of choice were golden syrup-water mixtures ranging in viscosity from 10-1 to 104 Pa*s and air. Two experimental apparatuses were used: a bi-dimensional and a tri-dimensional one. The bi-dimensional set-up is a cell made of two flat transparent PVC plates (44x23cm) 10mm or 5mm apart (the front one having a hole at the bottom permitting bubble injection) containing a variety of parallelepipeds apt to outline different plumbing system geometries. The tri-dimensional one consists of a cylindrical tube (r=1,5cm; l=7cm) allowing bubble injection through the bottom rubber tap and terminating into a square tank (l=22cm). Results indicate that conduit geometry directly controls the slug rise velocity and the surrounding liquid descending speed, which in turn control the slug stability. Small enough bubbles simply deform as they go through the flaring, while bigger ones split into two daughter bubbles. A regime diagram has been constructed, illustrating the bubble break-up threshold dependence on the flare geometry and initial slug size, the two main controlling factors. The phenomenon of bubble break-up implies that there is a maximum size a system of a certain shape and size can deliver. The size of the upper daughter bubble has been measured in a variety of experiments, and it has been found to be independent of the original slug size, but related to the conduit-upper reservoir transition geometry. It has therefore been possible to establish a relation between conduit geometry and first emerging daughter bubble size. Under the reasonable assumption of a non-limiting supply of gas, this allowed to successfully design the envisaged model of conduit geometry inferral from delivered bubbles size. Data on the size of emerging bubbles, necessary to feed the model, can be obtained through infrasound techniques, as a bursting over-pressurized gas bubble produces a characteristic seismoacoustic signal, from which it is possible to infer its size.

Soldati, A.; Cashman, K. V.; Rust, A.; Rosi, M.

2013-12-01

111

Alkali metal vapor detector  

International Nuclear Information System (INIS)

This detector is characterized by a sensor including an electricity conductor element in gold and antimony, whose ends are related to two electric conductors; it includes also detection means, related to these conductors, of an important variation of the gold or antimony conductor electric resistance or of another electric quantity depending of this resistance; this variation results from the gold or antimony reaction with alkali metal vapors; it includes at last a safety device controlled by those detection means. This is used noticeably in the nuclear field and sodium cooled furnaces

1985-01-07

112

Mud energized electrical generating method and means  

Energy Technology Data Exchange (ETDEWEB)

A drilling instrument adapted to be positioned in a conduit for the flow of mud. The instrument has a passage sealing a fluid from the mud. Means is responsive to energy derived from the mud for causing the sealed fluid to flow. An electrical generator derives energy from the flowing fluid to provide electrical energy.

Dailey, P. E.

1985-05-07

113

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)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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

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

114

Stenting an aortopulmonary conduit with peripheral cardiopulmonary bypass support.  

Science.gov (United States)

Although surgically created aortopulmonary (AP) shunts are uncommon in the adult congenital heart disease population, they are often used in patients with pulmonary atresia. For these patients, the shunt is a vital supply of pulmonary blood flow and thus obstruction of the shunt may lead to pulmonary hypoperfusion and hypoxia thereby increasing morbidity and mortality. This report describes a safe and effective method of stenting the conduit with the hemodynamic support of peripheral cardiopulmonary bypass (PCB). Prior to the procedure, a multimodality assessment of a stenosis in a kinked AP conduit using computed tomography, angiography, intravascular ultrasound (IVUS), and pressure wire assessment (PWA) was utilized. While PCB, IVUS, and PWA have all been used to great effect in various clinical scenarios, the combined use of these techniques has not been previously been described in the setting of intervention in adult congenital heart disease. PMID:23592486

Incani, Alexander; Lee, Joseph C; Nicolae, Mugur J; Walters, Darren L

2014-01-01

115

Tension layer winding of cable-in-conduit conductor  

International Nuclear Information System (INIS)

A 710 mm i.d. by 440 mm long, 6 layer Cable-in-Conduit (CIC) coil was precision tension layer wound with Incoloy 908 jacketed conductor to model winding technology that will be used for the Nb3Sn outsert coils of the 45 Tesla Hybrid Magnet Project at the US National High Magnetic Field Laboratory. This paper reports on the set up of a new winding facility with unique capabilities for insulating and winding long length CIC conductor and on special procedures which were developed to wind and support layer to layer transitions and to safely form conductor into and out of the winding. Analytical methods used to predict conduit keystoning, springback and back tensioning requirements before winding are reported in comparison to results obtained during winding and actual winding build-up dimensions on a layer by layer basis in comparison to design requirements

1996-07-01

116

Solute transport modelling in karst conduits with slow zones during different hydrologic conditions  

Science.gov (United States)

SummaryEight tracer tests conducted under different flow conditions in two well-developed karst connections in the Santa Eufemia-Ereñozar karst unit (Basque Country, northern Spain) are considered for transport characterization. Lithium tracer was injected as an impulse release for obtaining well-defined tracer breakthrough curves (TBCs). In order to simulate curve evolution and obtain transport characteristic parameters, two approaches have been applied: a standard analytical solution and a new numerical one that accounts for transient storage processes. The numerical model simulates the effect of localized variations in conduit geometry that give way to dead zones or slow zones in the transport process. This model fits the experimental curves well and explains their tails mainly by diversion processes from the main flow line towards stagnant zones. An increase in dispersion coefficient values is observed in both conduits as flow rates and average flow velocities increase. Stagnation and tracer transient retention processes, which may be quantified by means of the numerical solution, are more important as circulating flow rates decrease and travel times increase. The diversion processes in the two connections follow a similar evolution, with significant changes in the magnitude of the retentions registered depending on the hydrodynamic state of the traced system. Consequently, there is a clear hydrodynamic-controlled tailing effect.

Morales, Tomás; Uriarte, Jesus A.; Olazar, Martín; Antigüedad, Iñaki; Angulo, Bárbara

2010-09-01

117

Operating strain effects in Nb3Sn cable-in-conduit conductors  

International Nuclear Information System (INIS)

Nb3Sn superconductors show a dependence of the critical current and temperature on the strain state of the superconducting material. The basic causes of Nb3Sn strain effects, primarily differential thermal contraction between elements of the strand, have been known for 30 years, but have received more attention lately as part of a drive to achieve much higher operating current densities and make use of them in practical multistrand cables. The use of the cable-in-conduit (CICC) type of conductors to achieve high current capacity has proved popular, as the conductors offer good local cooling of the strands and distributed electrical contact between strands that is essential to provide stability against the inevitable current non-uniformity that arises with parallel connection of the strands. However, the essential openness of the cable means that the strands have to support local magnetic loads as well as being exposed to the overall magnet strain displacements. Simple structural models are developed based on mechanical measurements on cable-in-conduit conductors which are able to successfully simulate the measured superconducting performance. These suggest that degradation observed in large cables is due to a combination of the repeated bending strain experienced by the strands and filament fracture, which is starting to occur to a significant extent in some large cables. Superconducting performance improvements in strands can only be properly utilized with improved support of the strands in the cable, implying a more ordered structure than in a multistage

2005-12-01

118

Vapor detection using resonating microcantilevers  

Energy Technology Data Exchange (ETDEWEB)

Changes in the resonance frequency of microcantilevers due to adsorption of analyte vapor on exposed surfaces is shown to provide a novel means for detection of the analyte. Frequency changes can be due to mass loading or adsorption-induced changes in cantilever spring constant. Sensitization to water vapor is demonstrated by coating cantilever surfaces with hygroscopic materials, such as phosphoric acid. Cantilevers coated with a thin gelatin film exhibit high sensitivity and a linear response with changes in relative humidity, apparently due to changes in the spring constant of the coated cantilever. In addition to frequency response, static cantilever deflection also changes with vapor adsorption. Both phenomena can be used to detect adsorbed vapors with picogram mass resolution. 19 refs., 2 figs.

Thundat, T.; Chen, G.Y.; Warmack, R.J.; Allison, D.P.; Wachter, E.A. (Oak Ridge National Lab., TN (United States))

1995-02-01

119

Conduit drilling at Unzen volcano, Japan: core description and interpretation  

Science.gov (United States)

A 1996-m-long hole has been drilled on a slanted trajectory that passed beneath Unzen volcano, Japan. The hole penetrated central conduit region of the volcano at ~1600 m below the summit. Drill cores at 50 m intervals were recovered from the hole. The principal facies of the drill cores in the conduit region are polymictic breccia and coherent dacite. The polymictic breccia is non-stratified, poorly sorted and made up of heterolithologic, polyhedral dacite clasts 10-50 mm across, which are embedded in a cogenetic matrix. Larger clasts up to 50 cm across rarely occur. The clasts consist of non-vesicular, porphyritic dacite, which varies in color (greenish grey to grey), alteration, phenocryst size and phenocryst proportion. They show clast-rotated texture, and no jigsaw-fit texture. The edges of the clasts are commonly rounded. The matrix of the breccia is reddish grey, dense (low porosity) and composed of angular dacite fragments up to 5 mm across. The coherent dacite is grey, massive and porphyritic. It contains plagioclase and hornblende phenocrysts. The matrix of the dacite is mostly crystalline, but gradation from light grey, crystalline dacite to dark grey, glassy dacite occurs. These polymictic breccia and coherent dacite have been in places intruded by veins up to 10 mm wide. The veins vary in color (white, greenish grey and black) and components (fine-grain cray minerals, coarse rock fragments). Some veins show laminations along the vein wall. The morphological features of the polymictic breccia suggest that the breecia formed within the conduit region of the volcano in response to fragmentation of rocks due to explosions, but did not extrude from the vent and recycled within the conduit region. The coherent dacite facies is probably a dyke with chilled margins. The veins may have formed by injections of high-temperature gas and/or liquid into fractures around dykes during dyke intrusions. The descriptions of the drill core, together with composition of drill cuttings, electric conductivity of the borehole (FMS image) and seismological data during 1990-1995 eruption, suggest that the conduit region of the Unzen volcano is 300-350 m wide at ~1600 m below the summit, and consists of polymictic breccia and several, parallel, vertical dykes, intruding the breccia. Each dyke is tabular-shaped and 3-30 m thick. Thin dykes (3-8 m thick) have simple, uniformed interior and are inferred to have formed by single injection of magma. On the other hand, thick dykes (26-30 m) have several cooling units within, and probably formed by several magma injections.

Goto, Y.; Nakada, S.; Yoshimoto, M.; Shimano, T.; Kurokawa, M.; Sakuma, S.; Sugimoto, T.; Noguchi, S.; Toramaru, A.; Hoshizumi, H.; Oguri, K.; Uto, K.

2004-12-01

120

Vaporization of perfluorocarbon droplets using optical irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Micron-sized liquid perfluorocarbon (PFC) droplets are currently being investigated as activatable agents for medical imaging and cancer therapy. After injection into the bloodstream, superheated PFC droplets can be vaporized to a gas phase for ultrasound imaging, or for cancer therapy via targeted drug delivery and vessel occlusion. Droplet vaporization has been previously demonstrated using acoustic methods. We propose using laser irradiation as a means to induce PFC droplet vaporization us...

Strohm, Eric; Rui, Min; Gorelikov, Ivan; Matsuura, Naomi; Kolios, Michael

2011-01-01

 
 
 
 
121

Theory of the airborne sound field generated in a resonant magma conduit  

Science.gov (United States)

Explosive sources triggered inside a magma conduit may excite the conduit into acoustic resonance. The acoustic field in the conduit can propagate into the atmosphere through an open vent and ensonify the overlying atmosphere. The character of the airborne sound field is determined by a combination of propagation and source effects: the resonance of the magmatic conduit and the diffraction of the sound field at the volcanic vent are acoustic propagation effects, whereas the explosion pressure signature and the firing rate of the explosions define the source characteristics. For wavelengths larger than the conduit radius, only the longitudinal resonances of the magmatic conduit are relevant, and the open vent radiates like a piston surrounded by an infinite baffle. In this case, the fluid particle velocities are directed along the axis of the conduit and the sound field may propagate into the surrounding bedrock through the conduit wall displacement induced by the fluid overpressure. This coupling may produce seismic signals with banded spectra, such as volcanic tremor and long-period events. The airborne pressure field retains the modal structure of the sound field in the magmatic conduit, which contains information on the conduit geometry and geo-acoustic properties of the magma. The seismic wavefield is driven by the acoustic field in the magma and also contains this information, although it may be filtered by propagation effects in the bedrock. The theoretical sound field in the magma conduit is used to interpret seismic tremor signals recorded at Mt. Spurr Volcano, Alaska. Rapid variations in the acoustic impedance of the magma conduit terminations can create systematic changes in the tremor spectra, which can be used to monitor changes in the magmatic system. The results of the modelling illustrate the difference between source effects and conduit resonance, as well as the value of seismoacoustic measurements in volcanic environments.

Garcés, Milton A.; McNutt, Stephen R.

1997-09-01

122

Twenty years' follow-up of portal vein conduits in liver transplantation.  

Science.gov (United States)

Portal vein problems remain a formidable challenge in liver transplantation. In select situations, a portal vein conduit can provide a solution. No long-term results have been reported. This study was designed to assess the impact of portal vein conduits on graft survival after liver transplantation and the safety of portal vein conduits and to establish the long-term results (up to 20 years) of portal vein conduits. Data from 2370 adult liver transplants were prospectively collected into a computerized research database and analyzed. All portal vein conduits were constructed from the donor iliac vein obtained at the liver retrieval. Portal vein conduits were required in 35 (1.5%) first transplants. The long-term (up to 20 years of follow-up) graft survival after liver transplantation using portal vein conduits was excellent and comparable to that of the control group. The graft survival was 65% with the conduit versus 66% without the conduit at 5 years of follow-up, 58% versus 51% at 10 years, and 48% versus 35% at 15 years. There was a higher rate (8.6% versus 1.4%) of portal vein thrombosis after the portal vein conduit, and the majority occurred in the first 3 months after transplantation. For the same time period, there was no statistically significant difference in graft survival or patient survival for the retransplants with and without portal vein conduits. There was no statistically significant difference in graft survival or patient survival for the transplants with portal vein conduits and with portal vein thrombendvenectomy. In conclusion, portal vein conduits can be used safely for liver transplantation with no negative impact on long-term graft survival or patient survival. Despite the higher rate of portal vein thrombosis in the immediate postoperative period, excellent long-term results can be obtained. PMID:19326411

Nikitin, Dmitriy; Jennings, Linda W; Khan, Tariq; Vasani, Sugam; Ruiz, Richard; Sanchez, Edmund Q; Chinnakotla, Srinath; Levy, Marlon F; Goldstein, Robert M; Klintmalm, Goran B

2009-04-01

123

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)

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.

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

1994-03-01

124

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O conceito do uso de um conduto extracardíaco para estabelecer uma via de saída, conectando o ventrículo direito com o tronco pulmonar, ou seus ramos, foi desenvolvido na década de 60. Entre 1971 e 1986, 335 pacientes receberam, no The Hospital for Sick Children, de Londres, condutos extracardíacos [...] para o lado direito do coração; 176 destes foram homoenxertos aórticos, preservados em solução antibióticonutriente; 140 heteroenxertos (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley e 19 tubos não valvulados. Estes condutos foram usados na correção de defeitos cardíacos complexos. A idade média foi de 6,34 anos e o peso médio, de 17,8 kg. O diâmetro interno dos condutos variou de 8 a 30 mm. A mortalidade hospitalar foi de 29,2% e o seguimento dos sobrevivente teve uma duração máxima de 14,3 anos, sendo que apenas 40% delas foram relacionadas ao conduto extracardíaco. A curva atuarial, livre de obstrução, dos condutos extracardíacos foi significativa, quando se analisaram os homoenxertos, face a cada grupo de heteroenxertos (p Abstract in english The concept of using extracardiac conduits, to establish an outflow tract between the right ventricle and the pulmonary artery was developed on the sixties. Between 1971 and 1986, 335 patients received extracardiac conduits for the right heart, at The Hospital for Sick Children, London; 176 were ant [...] ibiotic preserved aortic homografts (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley) and 19 non-valved tubes. These conduits were used for the repair of complex congenital heart defects. The mean age of these groups was 6.34 ± 4.6 years and the mean weight 17.8 ± 10.8 kg. The internal diameter of the conduits varied from 8 to 30 mm. The hospital mortality was 29.2% and long-term follow-up of the survivals had a maximum period of 14,39 years. Sixty patients (17.9%) were submited to 60 reoperations, being only 40% conduit related. The actuarial survival cun/e of freedom from obstruction was significant when analyzed the homografts, without Dacron, versus each group of heterografts (p

Almeida, Rui Siqueira de; Wyse, Richard; Leval, Marc De; Stark, Jaroslav.

125

Shallow conduit processes of the 1991 Hekla eruption, Iceland  

Science.gov (United States)

On January 17, 1991 at 17:00 hrs, the 17th eruption of Hekla since 1104AD began. Lasting for almost two months, it produced 0.02 km3 of icelandite tephra and ~0.15km3 of icelandite lava. This eruption was the third of four eruptions since 1980 with a recurrence period of approximately 10 years, as opposed to a recurrence interval of c. 55 years for the eruptions in the period 1104AD to 1947AD. [1] The last four Hekla eruptions are typified by a 0.5-2 hour-long initial phase of subplinian intensity and discharge ranging from 2900-6700 m3/s [2]. In all 4 events the inital phase was followed by a sustained and relatively low-discharge(Hekla 1991 lasted until the 11th March 1991 [1]. The initial phase of the 1991 event lasted for ~50 minutes and sustained an eruption plume that rose to 11.5 km in about 10 minutes [1]. The plume was dispersed to the NNE at velocities of 60-70 km/hr producing a well-sorted tephra fall covering >20,000 km2. Here we examine the first phase of the Hekla 1991 eruption with focus on vesiculation and fragmentation processes in the shallow conduit and ash production. Samples of the tephra fall were collected on snow immediately after the initial phase at multiple sites providing a representative spatial coverage within the 0.1mm isopach [3]. This set was augmented by samples collected in 2012 to provide tighter coverage of near vent region. Grain size of all samples has been measured down to 1 micron. Density measurements have been conducted on 4 near-vent pumice samples (100 clasts each) and the pumice vesicle size distribution has been determined in a selected subset of clasts. The reconstructed whole deposit grain size distribution exhibits a unimodal, log-normal distribution peaking at -3 phi, typical of dry, magmatic fragmentation. Pumice densities range from 520-880 kg/m3 and exhibit a tight unimodal and log-normal distribution indicating a mean vesicularity of 77% to 79% for the magma erupted during the initial phase. Along with preliminary results for bubble number density and vesicle size distribution this implies a single late-stage homogeneous bubble nucleation and very uniform conditions of magma fragmentation during this short-lived initial phase of the Hekla 1991 eruption. 1. Gudmundsson, A., et al., The 1991 eruption of Hekla, Iceland. Bulletin of Volcanology, 1992. 54(3): p. 238-246. 2. Höskuldsson, Á., Óskarsson, N., Pedersen, R., Grönvold, K., Vogfjörd, K. & Ólafsdóttir, R. 2007. The millennium eruption of Hekla in February 2000. Bull Volcanol, 70:169-182. 3. Larsen, G., E.G. Vilmundardóttir, and B. Thorkelsson, Heklugosid 1991: Gjóskufall og gjóskulagid frá fyrsta degi gossins. Náttúrufrædingurinn, 1992. 61(3-4): p. 159-176.

Gudnason, J.; Thordarson, T.; Houghton, B. F.

2013-12-01

126

Pseudotachylyte formation in volcanic conduits: Montserrat vs. Mount St. Helens  

Science.gov (United States)

Seismogenic fracture and faulting may result in non-equilibrium frictional melting of rock, which upon cooling and recrystallisation forms pseudotachylyte. In volcanic environments, the transition from endogenous to exogenous growth can be attributed to a shift in magma rheology into the brittle regime, and thus the ascent of high-viscosity magma can form discrete shear zones, comparable to tectonic faults, along conduit margins. Pseudotachylytes have, until now, rarely been noted in exogenous volcanic materials and seldom in active volcanic environments. This is despite the simultaneous occurrence of high pressures and differential stresses, which make high-viscosity magmas ideal candidates for the occurrence of frictional melting. Here, we compare the chemical, thermal, magnetic and structural properties of two candidate volcanic pseudotachylytes; one from Soufriere Hills (Montserrat) and one from Mount St. Helens (USA). Additionally, we present data from a set of high-velocity rotary shear experiments on the host materials of these natural pseudotachylytes in which melting was induced after just 10's of centimeters of slip at realistic extrusion velocities (0.4 - 1.6 ms-1) and low normal stresses (0.5-2 MPa). After 1-2 meters of slip a continuous melt layer formed, at which point friction decreased and the fault zone displayed slip-weakening behaviour. For volcanic conduits, this would facilitate temporarily elevated slip rates, or an increase in extrusion rate, and could cause transitions in dome morphology and eruption style. This study demonstrates that shear fracturing in magma or sliding along conduit margins can readily result in frictional melting. The conspicuous absence of pseudotachylytes in active volcanic environments is likely the result of exceptionally high background temperatures which precipitate near-equilibrium melting, thereby obviating one of the characteristic signatures of pseudotachylyte - glassy protomelts formed by selective melting of crystals. In addition, the high ambient temperatures force slow recrystallisation of the homogenised melt into a microgranular layer, and as such, volcanic pseudotachylytes may be mistaken for cataclasites or chilled margins.

Kendrick, J. E.; Lavallee, Y.; Petrakova, L.; Ferk, A.; Di Toro, G.; Hess, K.; Ferri, F.; Dingwell, D. B.

2012-12-01

127

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

Science.gov (United States)

This study developed a biodegradable nerve conduit with PLA non-woven fabric and evaluated its nerve regeneration-promoting effect. The buccal branch of the facial nerve of 8 week-old Lewis rats was exposed, and a 7 mm nerve defect was created. A nerve conduit made of either PLA non-woven fabric (mean fibre diameter 460 nm), or silicone tube filled with type I collagen gel, or an autologous nerve, was implanted into the nerve defect, and their nerve regenerative abilities were evaluated 13 weeks after the surgery. The number of myelinated neural fibres in the middle portion of the regenerated nerve was the highest for PLA tubes (mean?±?SD, 5051?±?2335), followed by autologous nerves (4233?±?590) and silicone tubes (1604?±?148). Axon diameter was significantly greater in the PLA tube group (5.17?±?1.69 µm) than in the silicone tube group (4.25?±?1.60 µm) and no significant difference was found between the PLA tube and autograft (5.53?±?1.93 µm) groups. Myelin thickness was greatest for the autograft group (0.65?±?0.24 µm), followed by the PLA tube (0.54?±?0.18 µm) and silicone tube (0.38?±?0.12 µm) groups, showing significant differences among the three groups. The PLA non-woven fabric tube, composed of randomly-connected PLA fibres, is porous and has a number of advantages, such as sufficient strength to maintain luminal structure. The tube has demonstrated a comparable ability to induce peripheral nerve regeneration following autologous nerve transplantation. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22689468

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

2014-06-01

128

Rotational pectoral musculocutaneous flap for the repair of gastric conduit necrosis in cervical esophagogastrostomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We experienced a case of wide necrosis of the cervical gastric conduit during esophageal cancer surgery. We attempted to repair this defect with various methods including conservative care, stents two times, and sternocleidomastoid muscle flap without successful results. Finally, we were able to reconstruct the gastric conduit defect with rotational pectoralis major musculocutaneous (PMM) flap. PMM flap is thought to be a reconstruction method applicable to the intractable gastric conduit def...

Kim, Jae Jun; Park, Jae Kil; Hwang, Sun Jin; Moon, Seok Whan

2012-01-01

129

Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Objectives To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React® BioConduit) implanted using the Bentall procedure over ten years in a single centre. Methods Between 27/10/99 and 19/01/08, the No-React® BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from quest...

Galiñanes Manuel; Meduoye Ayo; Ferreira Ignacio; Sosnowski Andrzej

2011-01-01

130

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 gr...

Pej?i? T.; Hadži-?oki? J.; A?imovi? M.; Markovi? B.B.; Maksimovi? H.M.; Milkovi? B.; Kajmakovi? B.

2007-01-01

131

Geometry and Hydraulics of Englacial Conduits, Storglaciaren, Sweden  

Science.gov (United States)

Englacial conduits are the primary structure responsible for transporting surface water to the base of a glacier, where it supplies the subglacial hydraulic system and, in turn, affects glacier movement. Despite the well-known theoretical descriptions of englacial conduits, little direct evidence exists about their geometry and hydraulics. In July 2001, we initiated a field effort on Storglaciären, Sweden, to intersect englacial conduits by drilling into the glacier using a hot water drill. A companion project (Jacobel et al., this session) attempted to detect the englacial conduits using ground-penetrating radar. In a typical borehole, the water level remained at the surface while drilling through the impermeable ice. Once a connection was made, the water level dropped roughly 10 m and remained low despite continued water pumping. A small video camera was lowered, with attachments, to measure the geometry of the opening, and water flow speed. The water level in the hole provided a piezometric measure of the pressure. We drilled 22 holes at 3 separate locations and 17 (77%) connected englacially, the remaining 5 reached the bed without englacial connection, of which 2 drained at the bed. The geometry of the connections was highly irregular in cross-section with 1-2 cm openings, reminiscent of crevasse-like features rather than circular cross-sections as anticipated from the theoretical literature. Flow behavior was observed by tracking particle motion. The flow was complicated, in part by the inferred tangential intersection between the borehole and structure, and by the observed surging behavior. Flow speeds were low, on the order of 1 cm sec-1. Water level records from 3 different holes over several days exhibited highly correlated variations and large diurnal excursions. In contrast, records from holes drilled to the bed showed little variation. Based on these measurements, our conceptual picture of the englacial system is that of a sluggish flow system composed of many passages with hydraulically inefficient cross-sections. In general, correlation between the radar images and directly measured connections was inconclusive. However, in one case we believe we drilled to a very clear linear subsurface structure imaged by the radar.

Fountain, A. G.; Schlichting, R.; Frodin, S.; Jacobel, R. W.

2001-12-01

132

Séparation de la source glottique des influences du conduit vocal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cette étude s'intéresse au problème de l'inversion d'un modèle de production de la voix pour obtenir, à partir d'un enregistrement audio de parole, une représentation de le source sonore qui est générée au niveau de la glotte, la source glottique, ainsi qu'un représentation des résonances et anti-résonances créées par le conduit vocal. Cette séparation permet de manipuler les éléments composant la voix de façon indépendente. On trouve de nombreuses applications de ce sujet ...

Degottex, Gilles

2010-01-01

133

Optimization and stability of a cable-in-conduit superconductor  

International Nuclear Information System (INIS)

The optimization process for strand number and diameter, cable void fraction, and Cu/NbTi-ratio of the cable-in-conduit conductor for the superconducting magnet system of the planned stellarator fusion experiment Wendelstein 7-X is presented. Main optimization criteria are stability and cable cooling requirements, taking into account transient disturbances and losses. A simple stability criterion regarding transient disturbances is used which is derived from cable compression experiments. The resulting data for the 16 kA, 6 T cable are: cable and strand diameter ?11.5 mm and ?0.57 mm, respectively, strand number ?250, void ?36%, and Cu/sc-ratio ?2.7

1996-07-01

134

Acoustic Behavior of Vapor Bubbles  

Science.gov (United States)

In a microgravity environment vapor bubbles generated at a boiling surface tend to remain near it for a long time. This affects the boiling heat transfer and in particular promotes an early transition to the highly inefficient film boiling regime. This paper describes the physical basis underlying attempts to remove the bubbles by means of pressure radiation forces.

Prosperetti, Andrea; Oguz, Hasan N.

1996-01-01

135

Hyporheic exchange in a karst conduit and sediment system - A laboratory analog study  

Science.gov (United States)

Karst conduits are often partly filled by clastic sediments. Flow through such sediments can have a strong impact on the fate of sediment-entrapped contaminants. In contrast to stream bed sediments, hyporheic flow in karst sediments has received little attention so far. For karst sediments, conduit bends could induce hyporheic flow, in addition to bedforms or obstacles. The main aim of this study was to investigate flow processes in a conduit-sediment system using a laboratory model resembling a siphon and numerical modeling. In the laboratory system, zones with forward and reserve flow occurred in the sediment due to the conduit bends. As demonstrated with sediment-source tracer test, entrapped solutes were generally flushed out more rapidly at a higher flow rate and steeper conduit angle. Numerical modeling assuming pressure continuity across the conduit-sediment interface reproduced the flow patterns and breakthrough curves (BTCs) well. Based on the model, the magnitude of hyporheic exchange is expected to increase linearly with the flow rate and was higher for a steeper conduit angle. However, the increase in flushing intensity was not evenly distributed throughout the sediments but occurred mainly adjacent to the conduit bends consistent with observations from tracer tests. This study confirms that conduit bends could have a strong influence on hyporheic flow in karst sediments.

Wu, Yuexia; Hunkeler, Daniel

2013-09-01

136

Chronic dissection and aneurysmal dilatation of a BioValsalva conduit.  

Science.gov (United States)

The BioValsalva (Vascutek Terumo, Renfrewshire, Scotland, UK) conduit is the first commercially available prefabricated bioprosthetic aortic valved conduit. We present a case of chronic dissection of a BioValsalva valved conduit presenting as a 7.5-cm aortic root aneurysm 1 year after a Bentall operation. Intraoperatively, the conduit was found to have dissected from the annulus upward, and the coronary buttons were avulsed from the inner layers while remaining attached to the outer layer. Both the outer layer and the coronary buttons were grossly dilatated. PMID:23816079

Yigzaw, Yikuno A; Lau, Kelvin K W; Baig, Kamran; Uppal, Rakesh

2013-07-01

137

System and method for bidirectional flow and controlling fluid flow in a conduit  

Energy Technology Data Exchange (ETDEWEB)

A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.

Ortiz, Marcos German (Idaho Falls, ID)

1999-01-01

138

Experimental rigidity evaluation of conduit pack for forced-flow superconducting coil  

International Nuclear Information System (INIS)

The compressive rigidity tests of the conduit pack were carried out in liquid helium for evaluating the coil rigidity, and the rigidity of the conduit was investigated by FEM analysis of the plane strain problem. Also, the conventional method for the estimation of the coil rigidity was proposed on the basis of the curved-beam theory, and the apparent rigidity of the conduit pack was calculated. By comparing these results, it is recognized the outer radius of the conduit has a strong effect on the coil rigidity and the proposed conventional method gives good results with the experimental ones

1993-07-12

139

Modeling blockage in unsteady slurry flow in conduits  

International Nuclear Information System (INIS)

Developments in the modeling of the inception of blockage in granular slurry systems are discussed from phenomenological and numerical experience. In addition, pump and valve manipulation procedures developed for controlling conduit blockage during transient operation are outlined. Conduit blockage is in itself a transient event and although it is most frequently associated with system start-up or shut-down, it can originate from steady state networks as a result of density waves, instabilities of the excursive type, and/or flow regime relaxation. Blockage control during system start-up or shut-down is accomplished by way of a pump/valve stroking procedure that emphasizes a gradual control of the fluid velocity rather than a maximum permissible pressure. This is done to promote an orderly settling of solids, needed for shut-down, or resuspension of solids, as needed for start-up. Recent evaluation of friction factors at the onset of blockage obtained through laboratory measurements of the shear stresses in a plugged pipe are also presented

1985-01-01

140

Conduit for high temperature transfer of molten semiconductor crystalline material  

Science.gov (United States)

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

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

1983-01-01

 
 
 
 
141

Hydraulic and geological factors influencing conduit flow depth  

Directory of Open Access Journals (Sweden)

Full Text Available There has much been speculation as to whether cave formation should occur at, above, or below the water table, but a satisfactory explanation has been lacking until recently. The last 50 years has seen extensive mapping of caves both above and, more recently, below the water table. It is now becoming apparent that there are systematic differences in depth of flow between different areas and that conduit flow to depths >100m below the water table is not uncommon. Such deep flow is facilitated by the lower viscosity of geothermally heated water at depth. Analysis of data from caves shows that depth of flow is primarily a function of flow path length, stratal dip and fracture anisotropy. This explains why conduits form at shallow depths in platform settings such as in Kentucky, at moderate depths (10–100m in folded strata such as in England and in the Appalachian Mountains, and at depths of several hundred metres in exceptional settings where there are very long flow paths.

Worthington,S.R.H.

2005-01-01

142

Calibrated vapor generator source  

Energy Technology Data Exchange (ETDEWEB)

A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

Davies, John P. (Idaho Falls, ID); Larson, Ronald A. (Idaho Falls, ID); Goodrich, Lorenzo D. (Shelley, ID); Hall, Harold J. (Idaho Falls, ID); Stoddard, Billy D. (Idaho Falls, ID); Davis, Sean G. (Idaho Falls, ID); Kaser, Timothy G. (Idaho Falls, ID); Conrad, Frank J. (Albuquerque, NM)

1995-01-01

143

The separation of hydrocarbons from waste vapor streams  

International Nuclear Information System (INIS)

Hydrocarbon vapors generated from industrial processes dispersed into air are contributing factors for the creation of photochemical smog. The separation of hydrocarbon vapor by means of membranes is in case of some applications a technically simple and economic process. A membrane vapor separation process with a following treatment of the retentate by catalytic incineration is introduced in this paper

1989-01-01

144

Uranium AVLIS vaporizer development  

International Nuclear Information System (INIS)

A uranium vaporization system has been developed to efficiently produce the large quantities of atomic uranium vapor that are required for an economic Atomic Vapor Laser Isotope Separation (AVLIS) process. The vapor produced is well collimated and electronically cold. Vapor is produced by high energy electrons which are magnetically steered to the melt surface. Contouring of magnetic fields helps to optimally format the primary electrons and to contain backscattered electrons. A highly compact electron beam system has been developed to facilitate modular packaging of vaporizer components. Electron beam system power will be provided by high power switching power supplies. These power supplies, which are nearing completion at LLNL, have high electrical efficiency and offer excellent protection against high voltage arcdowns. Vapor density, composition, and quality are monitored by laser absorption spectroscopy. All laser and optical components are mounted outside the process chamber. The monitoring system is nonintrusive and is designed to survive long duration operation at high vaporization rates. Computer processing of laser data permits real time monitoring of vaporizer performance. Vapor density and composition are input to an internal model based controller which regulates feed rate and power to maintain desired process conditions. All vaporizer system components are in the final stages of development. Vaporization rate and vapor quality requirements have been met. Current efforts are directed toward reliability improvement and cost reduction. Computer controlled, high vaporization rate operation of the integrated vaporizer system has been demonstrated during uranium enrichment runs in excess of 100 hours duration

1993-01-16

145

Retubularization of the ileocystoplasty patch for conversion into an ileal conduit  

Science.gov (United States)

Introduction: We present the outcomes and long-term follow-up of patients who underwent conversion to an ileal conduit urinary diversion using the retubularized patch from the initial augmentation ileocystoplasty. Methods: We reviewed the charts of all patients who underwent this surgery at our centre. The indications for surgery, workup, clinical outcomes and complication rates were assessed. Patient-reported symptom response based on global response assessment (GRA) was determined and used as a subjective measure of overall treatment effectiveness. Results: Thirteen patients with either bladder pain syndrome/interstitial cystitis (BPS/IC) (n = 11) or neurogenic bladder (n = 2) were followed for a mean of 80 months. The most common indication for surgical conversion was persistent lower urinary tract symptoms (LUTS) or bladder pain. Late complications were frequent, typically low-grade, and usually manageable with conservative therapy; the most common were urinary tract infections (n = 6) and parastomal hernias (n = 5). Two patients developed ureteric strictures. Nine of 13 patients required additional surgery to manage complications or persistent symptoms. Only 5 of 11 GRA respondents reported a successful therapeutic outcome and BPS/IC patients who underwent concurrent cystourethrectomy tended to be most satisfied (2/3). Nevertheless, several patients still achieved symptom control when no other treatment options were available to them. Conclusion: Conversion to an ileal conduit using the retubularized ileocystoplasty patch offers several technical and therapeutic advantages over creating a urinary diversion from a new bowel segment. It should therefore be considered a viable treatment option in patients who have exhausted more conservative management of their LUTS.

Massaro, Peter A.; Gajewski, Jerzy B.; Bailly, Greg

2013-01-01

146

Fuel vaporizer and carburetor preheater system  

Energy Technology Data Exchange (ETDEWEB)

An apparatus for preheating the fuel and carburetor of an internal combustion engine and for improving vaporization of the fuel is disclosed herein which comprises a fuel chamber received within a cylindrical heat chamber including a heated liquid therein. The apparatus further includes a vaporization assembly mounted between the carburetor and intake manifold and providing, consecutively, a first screen, heat tubes and second screen. Means are provided for circulating the heat medium between the heat chamber, in which the medium is heated, and the vaporization assembly. Pump means are also provided for moving the fuel from the fuel chamber to the carburetor.

Mccord, R.L.

1982-08-03

147

A novel use of human acellular dermis for conduit salvage after esophagectomy.  

Science.gov (United States)

Postesophagectomy anastomotic leaks cause significant morbidity and mortality. Esophageal diversion is often required when extensive tissue loss precludes primary repair. We describe a technique in which human acellular dermis (AlloDerm) is used to repair the conduit, and report a series of 3 patients with significant anastomotic dehiscence whose conduits were salvaged using this technique. PMID:24694437

Thomas, Mathew; Allen, Mark S; Shen, K Robert; Wigle, Dennis A

2014-04-01

148

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

Science.gov (United States)

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.

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

2009-01-01

149

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

1995-03-01

150

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

Science.gov (United States)

...Municipal Water District Notice of Surrender of Exemption (Conduit) Pursuant to section 4.95(a) of the Commission's regulations...18 CFR 4.95(a) (2011). \\2\\ The Commission issued a conduit exemption for Project No. 11651 on June 7, 1999....

2011-08-29

151

Ground water flux distribution between matrix, fractures, and conduits: constraints on modeling  

Directory of Open Access Journals (Sweden)

Full Text Available Calculations are presented to show the relative contribution of the matrix, fracture, and conduit permeability to the overall flow of ground water through a karst aquifer. The conceptual model is a cross-section spanning the full width and thickness of the aquifer. A constant, but adjustable head is assumed. The rock matrix is characterized by an adjustable hydraulic conductivity. Varying proportions of fractures and conduits of adjustable fracture apertures and conduit diameters were the calculational parameters. Calculations used Darcy’s law for matrix flow, the cube law for fracture flow, and the Darcy-Weisbach equation for conduit flow. The results show a surprising dominance of fracture flow in the early stages of aquifer development. A focusing mechanism is needed to localize the flow into a relatively small number of conduits.

White,W.B.

2005-01-01

152

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)

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.

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

1996-12-31

153

Nerve conduit using fascia-wrapped fibrocollagenous tube.  

Science.gov (United States)

The purpose of this study was to evaluate the application of autogenous fascia as a framework of a fibrocollagen tube for a nerve conduit in Japanese white rabbits. The fascia was wrapped with a double layer around a silicone rod 3.0 mm in diameter. After the implantation of the fascia-wrapped silicone rod into a subcutaneous pocket for 2 weeks, a 3.0 x 30-mm fascia-wrapped fibrocollagen (FFC) tube was prepared. With microvascular techniques, the tube was interposed into a right sciatic nerve gap which was 25 mm long. The results of nerve regeneration in the FFC tube group, in particular, the formation of epineurium, were able to stand comparison with the results of a control group under both histologic and electron micrographic examination. PMID:11499471

Watanabe, K; Tsukagoshi, T; Kuroda, M; Hosaka, Y

2001-07-01

154

Development and manufacturing of superconducting cable in conduit conductors  

Science.gov (United States)

The cable in conduit (CIC) technology has proved to be an extremely valid application for the fabrication of conductors used in thermocontrolled nuclear fusion in magneto hydrodynamic and for energy storage. EUROPA METALLI - LMI began developing the CIC technology in the framework of a Contract with ENEA of Frascati producing a Niobium Tin superconducting CIC cable. EUROPA METALLI - LMI has gained its industrial experience in CIC cables during the production of a Niobium Titanium superconducting cable for the National Research Council of Italy under a Finalized Project “Superconductine and Cryogenic Technologies”. The cable will be used by ANSALDO GIE for the winding of a dipole magnet for magneto hydrodynamic applications. The present paper reports the status reached at EUROPA METALLI - LMI for the fabrication and testing of conductors.

Garrè, Riccardo; Conti, Stefano; Donati, Guglielmo; Rossi, Sergio

155

Optimum thermohydraulic operation regime for cable in conduit superconductors (CICS)  

Science.gov (United States)

For large superconducting coils e.g. in tokamaks, stellarators or high energy experimentaldevices it is advantageous to use cable in conduit superconductors (CICS). Successful development of such conductors has been going on for several years. For the design of a cryogenic cooling system it is of much importance to know the operating parameters e.g. inlet pressure, pressure drop, massflow and inlet temperature, where, with the least amount of massflow, the maximum heat can be extracted from the conductor. The paper will deal with the thermodynamic behaviour of helium flowing in channels and the possible heat input in a CICS. Using a set of typical conductor data a method will be shown to find the optimum operating parameters.

Katheder, H.

156

Stability and thermal equilibrium in cable-in-conduit conductors  

International Nuclear Information System (INIS)

The stability of modern superconductors depends not only on the cooling and the amount of copper in the cross section of the strands but also on the smoothness of the transition from the superconducting into the normal state. Frequently the latter factor is much more important than the cooling and the copper content. Superconductors with a broad transition are more stable and easier to control than the superconductors with a sharp transition, although the price for better stability might be somewhat lower operating current. The paper gives thermal equilibrium equations and stability criteria against small perturbations and determines the ultimate current that could be reached by a cable-in-conduit conductors depending on operating conditions. The effects of various factors (e.g., magnetic field profile, mass flow and smoothness of the transition to normal state) on the thermal equilibrium and ultimate current are studied and discussed

2004-01-15

157

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

1998-04-01

158

Hydraulic boundary conditions as a controlling factor in karst genesis: A numerical modeling study on artesian conduit development in gypsum  

Science.gov (United States)

A coupled continuum-pipe flow model is employed to simulate the development of karst conduits in an artesian setting, where aggressive water flows upward from an insoluble aquifer into a gypsum unit. Speleogenetic processes and controlling parameters are identified first for single conduit development. It is demonstrated that transient flow from the conduit into the surrounding fissured system of the rock enhances solutional conduit enlargement. Moreover, single conduit development is found to be highly sensitive to variations in initial diameter and hydraulic gradient. Simulating the solutional enlargement of pipe networks reveals that these two factors determine the resulting conduit pattern. Structural preferences are found to be essential for horizontal conduit development, otherwise flow paths are solely enlarged in vertical direction following the hydraulic gradient. Hydraulic gradients that increase with time can limit the extension or completely inhibit the development of horizontal caves even if lateral conduit development was structurally preferred.

Birk, Steffen; Liedl, Rudolf; Sauter, Martin; Teutsch, Georg

2003-01-01

159

Seismological analysis of conduit dynamics in fragmentation experiments  

Science.gov (United States)

simulate gas-burst and volcanic explosions under controlled laboratory conditions inducing fragmentation of volcanic rocks by rapid depressurization. A series of experiments were performed in a shock-tube apparatus at room temperature and a pressure range of 4 to 20 MPa using Argon (Ar) gas and, particles or pumice samples of different porosities. The instrumentation of this system with high-precision piezoelectric sensors enabled us to capture elastic waves and to recognize their characteristic signatures. By relating these signals to physical processes in the wave field, we have been able to characterize the conduit mechanism and the source dynamics. We compare and discuss conspicuous features of the waveforms and frequency spectra of these experimental signals with those of volcanic origin. Despite the fact that these signals are different in amplitude (resulting from different scale conditions); our observations indicate that the physical processes that occur during simulated explosions and those that occur during volcanic eruptions yield comparable signatures in their respective records. The effects of the source-receiver configuration and resonance also have significant implications. All this suggests that the physical processes (e.g. pressurization and depressurization of a system) involve a system response that causes similar distinctive effects independent of the system size, reflecting its intrinsic dynamics. These similarities imply that powerful constraints on the source mechanisms of volcanic seismicity can emerge from seismic investigations of experimental simulations of volumetric sources. Such constraints may yield significant advances in the understanding of volcanic conduit dynamics and in the interpretation of seismic unrest at volcanic centers.

Arciniega-Ceballos, A.; Alatorre-Ibargüengoitia, M.; Scheu, B.; Dingwell, D. B.; Delgado-Granados, H.

2014-03-01

160

Method for recovery of petrol gasoline from a mixture of petrol vapor and air, and a system for use in the method  

Energy Technology Data Exchange (ETDEWEB)

In a method of the type where petrol is recovered from a mixture of petrol vapor and air by absorption of the petrol in a cooled petroleum distillate, a petroleum distillate having a boiling point range higher than that of the petrol is used, and this petroleum distillate is in sequence cooled by heat exchange with a cold reservoir, brought into direct contact with the petrol/air mixture to absorb petrol, transferred to a buffer tank and transferred from the buffer tank to a stripping means which may be a distillation column. By combining cooling condensation and absorption of the petrol vapor and controlling the amount of cooled petroleum distillate brought into contact with the petrol/air mixture so that the petrol concentration in the petroleum distillate transferred to the buffer tank is substantially constant, an unprecedented optimum control of the petrol absorbing process can be obtained both in peak load and in average load operations. A system for carrying out the method is advantageous in that only the absorption means need be dimensioned for peak load operation, while the other components, such as the distillation column or a heat exchanger with associated conduits can be dimensioned for average loads, a buffer tank being provided to temporarily receive the petroleum distillate which owing to the above-mentioned control has a substantially constant, maximum petrol concentration so that the system can cope with peak loads with a surprisingly small buffer tank.

Jacobsen, A. J.

1984-10-09

 
 
 
 
161

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)

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.

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

1990-12-31

162

Engineering a multimodal nerve conduit for repair of injured peripheral nerve  

Science.gov (United States)

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.

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

163

Degradation properties of the electrostatic assembly PDLLA/CS/CHS nerve conduit  

Energy Technology Data Exchange (ETDEWEB)

A poly(d,l-lactic acid)/chondroitin sulfate/chitosan (PDLLA/CS/CHS) nerve conduit for repairing nerve defects was prepared by electrostatic assembly and the thermally induced phase separation technique. The hydrophilic characteristics of the PDLLA/CS/CHS assembly nerve conduits were improved markedly. The degradation behavior of the nerve conduit with various assembly layers was evaluated by a pH change, weight loss rate and molecular weight change. The pH of the solution of the nerve conduit could be effectively adjusted by varying the layer numbers and overcoming the acidity-caused auto-acceleration of PDLLA; the nerve conduit can retain its integrity in a phosphate buffer solution after being degraded for 3 months. After such a conduit was implanted in the rat for 3 months, obvious degradation occurred, but the regenerated nerve was integrated and it grew successfully from the proximal to distal nerve stump. All these results implied that the degradation rate of the prepared conduit can adapt to the regeneration of the peripheral nerve, which might be a new derivative of PDLLA-based biodegradable materials for repairing nerve injuries without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as shown by PDLLA.

Xu Haixing [School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070 (China); Yan Yuhua; Wan Tao; Li Shipu, E-mail: yanyuhua8@126.co [Biomedical Materials and Engineering Research Center, Wuhan University of Technology, Wuhan 430070 (China)

2009-08-15

164

Degradation properties of the electrostatic assembly PDLLA/CS/CHS nerve conduit  

International Nuclear Information System (INIS)

A poly(d,l-lactic acid)/chondroitin sulfate/chitosan (PDLLA/CS/CHS) nerve conduit for repairing nerve defects was prepared by electrostatic assembly and the thermally induced phase separation technique. The hydrophilic characteristics of the PDLLA/CS/CHS assembly nerve conduits were improved markedly. The degradation behavior of the nerve conduit with various assembly layers was evaluated by a pH change, weight loss rate and molecular weight change. The pH of the solution of the nerve conduit could be effectively adjusted by varying the layer numbers and overcoming the acidity-caused auto-acceleration of PDLLA; the nerve conduit can retain its integrity in a phosphate buffer solution after being degraded for 3 months. After such a conduit was implanted in the rat for 3 months, obvious degradation occurred, but the regenerated nerve was integrated and it grew successfully from the proximal to distal nerve stump. All these results implied that the degradation rate of the prepared conduit can adapt to the regeneration of the peripheral nerve, which might be a new derivative of PDLLA-based biodegradable materials for repairing nerve injuries without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as shown by PDLLA.

2009-08-01

165

Simulating the Development of Solution Conduits in Dualistic Karst Flow Systems  

Science.gov (United States)

Karst aquifers consist of highly permeable solution conduits embedded in the considerably less permeable fissured system of the adjacent rock. Hydrogeologic characterisation of these heterogeneous, dualistic flow systems requires a sound understanding of the processes involved in karstification. During the last decade numerical simulations of conduit development were frequently employed to accomplish this aim. Yet, in many of the earlier simulations the dualistic nature of the flow system and the feedback of conduit development on the hydraulic boundary conditions of the conduit system had been ignored. In this study, the dual flow system is adequately represented by a coupled continuum-pipe flow model. In order to simulate conduit development, the flow model is coupled to a module calculating dissolution rates and the corresponding widening of conduits depending on flow conditions. It is a major advantage of this modelling approach that the hydraulic boundary conditions for the conduit system do not need to be set a priori but can be obtained by a coupling to the continuum flow model representing the regional hydraulic system. This is illustrated using the example of an artesian setting, in which an unit of soluble rock is supplied with solutionally aggressive water from an aquifer below. It is demonstrated that the flow field changes both locally and at the regional scale due to solutional conduit development. These changes have to be taken into account, in order to gain adequate understanding of how the interaction of flow and dissolution processes determines the structure of the karst conduit system developing in this type of setting.

Birk, S.; Liedl, R.; Sauter, M.; Teutsch, G.

2002-12-01

166

Representation of water abstraction from a karst conduit with numerical discrete-continuum models  

Directory of Open Access Journals (Sweden)

Full Text Available Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most karst models assume quasi steady-state flow in conduits neglecting conduit associated drainable storage (CADS. The concept of CADS considers storage volumes, where karst water is not part of the active flow system but rather hydraulically connected to conduits (for example karstic voids and large fractures. The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g. large scale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this paper is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical hybrid model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1 is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The affect and proper functioning of these modifications is demonstrated by simplified model studies. Both enhancements, CAD storage and the FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is potentially able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems.

T. Reimann

2013-04-01

167

Representation of water abstraction from a karst conduit with numerical discrete-continuum models  

Science.gov (United States)

Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix, resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most mathematical karst models assume quasi-steady-state flow in conduits neglecting conduit-associated drainable storage (CADS). The concept of CADS considers storage volumes, where karst water is not part of the active flow system but hydraulically connected to conduits (for example karstic voids and large fractures). The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g., large-scale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed-head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this work is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical discrete-continuum model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ) boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The effects and the proper functioning of these modifications are demonstrated by simplified model studies. Both enhancements, CADS and FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems, as illustrated by its application to the Cent Fonts karst system.

Reimann, T.; Giese, M.; Geyer, T.; Liedl, R.; Maréchal, J. C.; Shoemaker, W. B.

2014-01-01

168

A sampling plan for conduit-flow karst springs: Minimizing sampling cost and maximizing statistical utility  

Science.gov (United States)

Analytical data for nitrate and triazines from 566 samples collected over a 3-year period at Pleasant Grove Spring, Logan County, KY, were statistically analyzed to determine the minimum data set needed to calculate meaningful yearly averages for a conduit-flow karst spring. Results indicate that a biweekly sampling schedule augmented with bihourly samples from high-flow events will provide meaningful suspended-constituent and dissolved-constituent statistics. Unless collected over an extensive period of time, daily samples may not be representative and may also be autocorrelated. All high-flow events resulting in a significant deflection of a constituent from base-line concentrations should be sampled. Either the geometric mean or the flow-weighted average of the suspended constituents should be used. If automatic samplers are used, then they may be programmed to collect storm samples as frequently as every few minutes to provide details on the arrival time of constituents of interest. However, only samples collected bihourly should be used to calculate averages. By adopting a biweekly sampling schedule augmented with high-flow samples, the need to continuously monitor discharge, or to search for and analyze existing data to develop a statistically valid monitoring plan, is lessened.Analytical data for nitrate and triazines from 566 samples collected over a 3-year period at Pleasant Grove Spring, Logan County, KY, were statistically analyzed to determine the minimum data set needed to calculate meaningful yearly averages for a conduit-flow karst spring. Results indicate that a biweekly sampling schedule augmented with bihourly samples from high-flow events will provide meaningful suspended-constituent and dissolved-constituent statistics. Unless collected over an extensive period of time, daily samples may not be representative and may also be autocorrelated. All high-flow events resulting in a significant deflection of a constituent from base-line concentrations should be sampled. Either the geometric mean or the flow-weighted average of the suspended constituents should be used. If automatic samplers are used, then they may be programmed to collect storm samples as frequently as every few minutes to provide details on the arrival time of constituents of interest. However, only samples collected bihourly should be used to calculate averages. By adopting a biweekly sampling schedule augmented with high-flow samples, the need to continuously monitor discharge, or to search for and analyze existing data to develop a statistically valid monitoring plan, is lessened.

Currens, J. C.

1999-01-01

169

Vapor phase pyrolysis  

Science.gov (United States)

The vapor phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is vaporized and the vapor is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated vapor to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the pressure differential between the vaporization region and the oxygen collection system with the aid of the environmental vacuum.

Steurer, Wolfgang

1992-01-01

170

Laparoscopic management of obstructed gastric conduit after minimally invasive esophagectomy.  

Science.gov (United States)

We describe a novel, minimally invasive method of managing an obstructed gastric conduit after minimally invasive esophagectomy. In addition, we briefly review the management of obstructed gastric conduit in patients status-post minimally invasive esophagectomy. On literature review, it was noted that gastrojejunostomy after esophagectomy was exceptionally rare. Only one other reported case of gastrojejunostomy after esophagectomy was found in the literature. This is the first reported case to our knowledge of laparoscopic gastrojejunostomy after minimally invasive esophagectomy (MIE). Laparoscopic gastrojejunostomy after minimally invasive esophagectomy for obstructed gastric conduit is technically feasible, and it effectively managed the obstruction in our patient. PMID:24792304

Friedman, Garrett; Copeland, Hannah; Astudillo, Juan Andres; Michelotti, Marcos; Wallen, Jason

2014-05-01

171

Data Transfer via Alternative Conduits: Using Fluid Networks  

Directory of Open Access Journals (Sweden)

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.

Charles Willow

2012-11-01

172

Structure of a Bacterial Cell Surface Decaheme Electron Conduit  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-23

173

Impact of cyclic stretch on induced elastogenesis within collagenous conduits.  

Science.gov (United States)

In vitro tissue engineering of vascular conduits requires a synergy between several external factors, including biochemical supplementation and mechanotranductive stimulation. The goal of this study was to improve adult human vascular smooth muscle cell orientation and elastic matrix synthesis within 3D tubular collagen gel constructs. We used a combination of elastogenic factors (EFs) previously tested in our lab, along with cyclic circumferential strains at low amplitude (2.5%) delivered at a range of frequencies (0.5, 1.5, and 3?Hz). After 21 days of culture, the constructs were analyzed for elastic matrix outcomes, activity of matrix metalloproteinases (MMPs)-2 and -9, cell densities and phenotype, and mechanical properties of constructs. While cell densities remained unaffected by the addition of stretch, contractile phenotypic markers were elevated in all stretched constructs relative to control. Constructs cultured with EFs stretched at 1.5?Hz exhibited the maximum elastin mRNA expression and total matrix elastin (over sixfold vs. the static EFs control). MMP-2 content was comparable in all treatment conditions, but MMP-9 levels were elevated at the higher frequencies (1.5 and 3?Hz). Minimal circumferential orientation was achieved and the mechanical properties remained comparable among the treatment conditions. Overall, constructs treated with EFs and stretched at 1.5?Hz exhibited the most elastogenic outcomes. PMID:24313750

Venkataraman, Lavanya; Bashur, Chris A; Ramamurthi, Anand

2014-05-01

174

Prediction of the phase distribution in a triangular conduit  

International Nuclear Information System (INIS)

The phase distribution in any two-phase flow system is one of the most important parameters for an accurate analysis of the momentum and heat transfer mechanisms. A multidimensional analysis of an accurate flow and void distribution can result in an accurate prediction of such important thermal-hydraulic phenomena as the local critical heat flux (CHF). However, numerous experimental and analytical studies of a two-phase flow in the past were not able to satisfactorily predict the lateral phase distribution in a wide range of conditions due to the uncertainties associated with the interfacial constitutive models and the turbulence models. There have been some numerical works to predict the phase distribution in two-phase bubbly flows. They predicted well the void peak near the wall for an up flow and the void coring for a down flow. However, there are few studies available on the void coring for an up flow. This study simulates the air/water measurements of a phase distribution in a triangular conduit which shows the void coring phenomena

2004-10-28

175

Finite element modelling of cable-in-conduit conductors  

International Nuclear Information System (INIS)

The ITER (International Thermonuclear Experimental Reactor) cable-in-conduit conductors (CICCs) are subjected to high thermal and electromagnetic cyclic loadings, responsible for conductivity loss in the strain-sensitive Nb3Sn strands. The complex mechanical phenomena occurring at the local scale of the strands make the final performances of the CICC difficult to predict from single-strand properties. In order to assess the amplitudes of the local strains that drive the conductor electrical behaviour, a nonlinear finite element simulation code is used. The successive stages of the conductors’ service life, from the forming of the cable to its thermal cool-down and Lorentz force loading, are simulated. Each strand is individually modelled and contact–friction interactions between the strands are considered. After a description of the issues regarding the modelling of the mechanical behaviour of cables and the main features of the finite element code employed, this paper presents the simulation results for the testing of pure copper wire inclusion for the conductor strain state. The code was then used to model four different cable designs in terms of twist pitches and void fractions. The analysis of the axial strain distributions within the cable is presented here. (paper)

2012-05-01

176

Prediction of the void coring phenomena in a triangular conduit  

International Nuclear Information System (INIS)

The phase distribution in any two-phase flow system is one of the most important parameters for an accurate analysis of the momentum and heat transfer mechanisms. A multidimensional analysis of an accurate flow and void distribution can result in an accurate prediction of such important thermal-hydraulic phenomena as the local critical heat flux. However, numerous experimental and analytical studies of a two-phase flow in the past were not able to satisfactorily predict the lateral phase distribution in a wide range of conditions due to the uncertainties associated with the interfacial constitutive models and the turbulence models. The previous study could not predict the void coring for the upward two-phase flow observed in the experiment. Recently, Tomiyama et al. showed that there is a critical bubble diameter causing the radial void profile transition from a wall peaking to a core peaking in an air-water bubbly flow. Using the transverse lift coefficient proposed by Tomiyama et al., this study simulated the void coring phenomena of the air-water flow in a triangular conduit and compared the predicted void distributions with the measurements

2005-05-26

177

Method of creating a cold water conduit to be used in ocean thermal energy conversion systems  

Energy Technology Data Exchange (ETDEWEB)

A method is disclosed of creating a cold water conduit for use with an ocean thermal energy conversion plant by drilling and blasting at least one passageway completely through an underwater land formation.

Green, W.; Calkins, D.; Gray, D.; Landers, E. Jr.

1983-08-09

178

78 FR 61958 - San Juan County Historical Society; Notice of Preliminary Determination of A Qualifying Conduit...  

Science.gov (United States)

...eight-inch diameter discharge pipeline leading to an existing 300-foot...six-inch diameter discharge pipeline that returns water to the Animas...conduit the facility uses is a tunnel, canal, Y pipeline, aqueduct, flume,...

2013-10-08

179

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

Science.gov (United States)

...generating unit; (3) a new, small pipeline discharging water into an existing 21-inch pipeline; and (4) appurtenant facilities...The conduit the facility uses is a tunnel, canal, Y pipeline, aqueduct, flume, ditch, or...

2013-10-09

180

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

Science.gov (United States)

...FPA 30(a)(3)(A), as amended by The conduit the facility Y HREA. uses is a tunnel, canal, pipeline, aqueduct, flume, ditch, or similar manmade water conveyance that is operated for the distribution of...

2013-10-18

 
 
 
 
181

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

Science.gov (United States)

...FPA 30(a)(3)(A), as amended by The conduit the Y HREA. facility uses is a tunnel, canal, pipeline, aqueduct, flume, ditch, or similar manmade water conveyance that is operated for the distribution of...

2013-11-21

182

78 FR 69403 - South Tahoe Public Utility District; Notice of Preliminary Determination of a Qualifying Conduit...  

Science.gov (United States)

...the existing C-Line export pipeline in South Tahoe Public Utility...18-inch-diameter Diamond Valley Ranch Loop pipeline; (2) an approximately 22-foot-wide...conduit the facility uses is a tunnel, canal, Y pipeline, aqueduct, flume,...

2013-11-19

183

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

Science.gov (United States)

...the 18-inch diameter water supply pipeline, (3) a 200-foot-long 18-inch diameter discharge pipeline leading to the water treatment plant...The conduit the facility uses is a tunnel, canal, pipeline, Y aqueduct, flume, ditch,...

2013-08-30

184

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

Science.gov (United States)

...eight-inch diameter intake pipeline receiving water flows from an...diameter filter pond diversion pipeline; (2) a new fiberglass shelter...conduit the facility uses is a tunnel, canal, Y pipeline, aqueduct, flume,...

2013-10-09

185

78 FR 68052 - Town of Telluride, Colorado; Notice of Preliminary Determination of a Qualifying Conduit...  

Science.gov (United States)

...FPA 30(a)(3)(A), as amended by The conduit the Y HREA. facility uses is a tunnel, canal, pipeline, aqueduct, flume, ditch, or similar manmade water conveyance that is operated for the distribution of...

2013-11-13

186

78 FR 62324 - Village of Oak Lawn, Illinois; Notice of Preliminary Determination of a Qualifying Conduit...  

Science.gov (United States)

...generating unit; (3) a new, small pipeline discharging water into an existing 36-inch pipeline; and (4) appurtenant facilities...conduit the facility Y HREA. uses is a tunnel, canal, pipeline, aqueduct, flume, ditch, or...

2013-10-16

187

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

Directory of Open Access Journals (Sweden)

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.

A?imovi? M.

2007-01-01

188

Development of bending characteristics for the TPX TF magnet coil cable-in-conduit conductor  

International Nuclear Information System (INIS)

The conductor for the toroidal field (TF) magnet coils for the Tokamak Physics experiment (TPX) is an assembly of stranded Nb3Sn superconductor sheathed by an Incoloy 908 conduit. The coil shape, when coupled with stiffness of the cable-in-conduit conductor (CICC) is such that conventional magnet winding techniques cannot be utilized. Therefore a bending and forming method will be employed in the TF coils. The cable will be reacted after bending because the reaction process hardens the conduit and also lowers the strain the cable can withstand without performance degradation. The Incoloy 908 conduit also work hardens quickly, necessitating the production of the required coil shape in one step without correction. This paper discusses the limiting processes for forming the TPX TF magnet geometry, the methods utilized in establishing the CICC bending characteristics and the methods employed to account for material springback so that a coil can be manufactured accurately and efficiently

1995-07-17

189

A Note on the Calculation of Averages in Superconducting Cable-in-Conduit Conductors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We show that there are two different ways of calculating the average electric field of a superconducting cable in conduit conductor depending on the relation between the current transfer length and the characteristic self-field length.

Anghel, A.

2013-01-01

190

Ureteric catheterization via an ileal conduit: technique and retrieval of a JJ stent  

Energy Technology Data Exchange (ETDEWEB)

Retrograde ureteric catheterization of a patient with an ileal conduit is difficult, because guide wires and catheters coil in the conduit. A modified loopogram, using a Foley catheter as a fulcrum through which catheters can be advanced to the ureteric anastomosis, is described. This technique was used to remove a JJ stent, which had been inserted previously across a stricture in one ureter, the stent crossing from one kidney to the other.

Wah, T.M.; Kellett, M.J. E-mail: mjkellett@bigwig.net

2004-11-01

191

Nerve gap repair by the use of artificial conduits and cultured cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. This thesis investigates the use of fibrin as both a tubular conduit to guide nerve regeneration and also as a matrix material to suspend various regenerative cell types within/on poly-3-hydroxybutyrate (PHB) nerve conduits. Adipose derived stem cells (ASC) are found in abundant quantities. In this thesis the ability of rat ASC to diff...

Kalbermatten, Daniel

2010-01-01

192

Bail out use of the Gore Excluder following pulmonary conduit rupture during transcatheter pulmonary valve replacement.  

Science.gov (United States)

This report describes the use of the Gore Excluder self-expanding stent to successfully exclude a contained right ventricle to pulmonary artery conduit rupture during transcatheter pulmonary valve replacement (tPVR). This stent was designed for percutaneous abdominal aortic aneurysm exclusion; however, its use in this setting allowed progression to tPVR following conduit rupture without the need for emergent surgery. PMID:22744905

Sosnowski, Cyndi R; Kenny, Damien; Hijazi, Ziyad M

2013-02-01

193

Absorption of glucose from urinary conduits in diabetics and non-diabetics.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ability of urinary conduits to absorb glucose was investigated. A solution containing 1% glucose and the inert marker phenol red was put into conduits in diabetic and non-diabetic patients. Samples were withdrawn at intervals for analysis and the fall in concentrations plotted against time. The loops in the patients without diabetes did not absorb glucose, but glucose was absorbed in one of the three diabetics. Ileal loops in patients with diabetes may absorb urinary glucose. This should ...

Sridhar, K. N.; Samuell, C. T.; Woodhouse, C. R.

1983-01-01

194

Novel use of biodegradable casein conduits for guided peripheral nerve regeneration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recent advances in nerve repair technology have focused on finding more biocompatible, non-toxic materials to imitate natural peripheral nerve components. In this study, casein protein cross-linked with naturally occurring genipin (genipin-cross-linked casein (GCC)) was used for the first time to make a biodegradable conduit for peripheral nerve repair. The GCC conduit was dark blue in appearance with a concentric and round lumen. Water uptake, contact angle and mechanical tests indicated tha...

Hsiang, Shih-wei; Tsai, Chin-chuan; Tsai, Fuu-jen; Ho, Tin-yun; Yao, Chun-hsu; Chen, Yueh-sheng

2011-01-01

195

Effects of dynamically variable saturation and matrix-conduit coupling of flow in karst aquifers  

Science.gov (United States)

Well-developed karst aquifers consist of highly conductive conduits and a relatively low permeability fractured and/or porous rock matrix and therefore behave as a dual-hydraulic system. Groundwater flow within highly permeable strata is rapid and transient and depends on local flow conditions, i.e., pressurized or nonpressurized flow. The characterization of karst aquifers is a necessary and challenging task because information about hydraulic and spatial conduit properties is poorly defined or unknown. To investigate karst aquifers, hydraulic stresses such as large recharge events can be simulated with hybrid (coupled discrete continuum) models. Since existing hybrid models are simplifications of the system dynamics, a new karst model (ModBraC) is presented that accounts for unsteady and nonuniform discrete flow in variably saturated conduits employing the Saint-Venant equations. Model performance tests indicate that ModBraC is able to simulate (1) unsteady and nonuniform flow in variably filled conduits, (2) draining and refilling of conduits with stable transition between free-surface and pressurized flow and correct storage representation, (3) water exchange between matrix and variably filled conduits, and (4) discharge routing through branched and intermeshed conduit networks. Subsequently, ModBraC is applied to an idealized catchment to investigate the significance of free-surface flow representation. A parameter study is conducted with two different initial conditions: (1) pressurized flow and (2) free-surface flow. If free-surface flow prevails, the systems is characterized by (1) a time lag for signal transmission, (2) a typical spring discharge pattern representing the transition from pressurized to free-surface flow, and (3) a reduced conduit-matrix interaction during free-surface flow. Copyright 2011 by the American Geophysical Union.

Reimann, T.; Geyer, T.; Shoemaker, W. B.; Liedl, R.; Sauter, M.

2011-01-01

196

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Liu, Ting

2011-01-01

197

Ureteric catheterization via an ileal conduit: technique and retrieval of a JJ stent  

International Nuclear Information System (INIS)

Retrograde ureteric catheterization of a patient with an ileal conduit is difficult, because guide wires and catheters coil in the conduit. A modified loopogram, using a Foley catheter as a fulcrum through which catheters can be advanced to the ureteric anastomosis, is described. This technique was used to remove a JJ stent, which had been inserted previously across a stricture in one ureter, the stent crossing from one kidney to the other

2004-11-01

198

Comparison and characterization of multiple biomaterial conduits for peripheral nerve repair.  

Science.gov (United States)

Four biomaterial tubes, poly(lactic-co-glycolic acid) (PLGA), poly(caprolactone fumarate) (PCLF), a neutral oligo[(polyethylene glycol) fumarate] (OPF) hydrogel or a positively charged oligo[(polyethylene glycol) fumarate] (OPF(+)) hydrogel with a PCLF sleeve, have previously been shown to have benefits for nerve repair. However, no direct comparison to identify the optimal material have been made. Herein, these nerve tubes were implanted in a rat sciatic nerve model and nerve regeneration was quantified and compared by using accepted nerve assessment techniques. Using standard statistical methods, no significant differences of individual parameters were apparent between groups despite PCLF showing a tendency to perform better than the others. Using a mean-variance based ranking system of multiple independent parameters, statistical differences became apparent. It was clear that the PLCF tube supported significantly improved nerve regeneration and recovery compared to the other three biomaterial conduits. The ability to simultaneously compare a number of regenerative parameters and elucidate the best material from the combination of these individual parameters is of importance to the nerve regeneration area and has implications for the tissue engineering field. By using this method of comparison, a number of biomaterial constructs may be compared under similar conditions and the optimal construct elucidated using the minimal number of animals and materials. PMID:23937914

Daly, William T; Knight, Andrew M; Wang, Huan; de Boer, Ralph; Giusti, Guilherme; Dadsetan, Mahrokh; Spinner, Robert J; Yaszemski, Michael J; Windebank, Anthony J

2013-11-01

199

Conduits for coronary artery bypass surgery: the quest for second best.  

Science.gov (United States)

Coronary artery bypass grafting is one of the most outstanding surgical achievements of the 20th century. Over its 50-year history patient outcomes have become excellent owing to technical refinements, myocardial protection, the use of antiplatelet and anticholesterol drugs, and the continued search for better conduits. The performance of conduits used for bypass remains the most important prognostic factor, with the left internal mammary artery being the conduit of choice due to its excellent patency rates. There is, however, uncertainty with regards which conduit is second best. The recent resurgence of the radial artery has led to an increase in its use as surgeons lean towards total arterial revascularization but there is emerging evidence that the performance of the long saphenous vein graft is improving. Furthermore, bilateral internal mammary artery grafting is preferred in some centres as an alternative approach to total arterial revascularization, with multiple reports of superior long-term event-free outcome with its use. This extensive review of current literature reveals an absence of clear consensus as to what mix of conduits provides the best long-term outcomes. The quest for second best continues. Arterial conduits appear to be superior when grafted to tight stenosis but veins remain popular with surgeons. More supportive evidence from the concluding Arterial Revascularization trial and the Radial Artery Patency and Clinical Outcomes trial should guide future practice. PMID:21430545

Bello, Sean O Z; Peng, Edward W K; Sarkar, Pradip K

2011-06-01

200

FRACTURE TOUGHNESS MEASUREMENTS AND ASSESSMENT OF THIN WALLED CONDUIT ALLOYS IN A CICC APPLICATION  

International Nuclear Information System (INIS)

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

2008-03-03

 
 
 
 
201

Evaluation of critical current performance of an Nb3Al conductor with stainless steel conduit  

International Nuclear Information System (INIS)

An Nb3Al conductor with stainless steel (SS) conduit has been developed in the framework of ITER Engineering Design Activity. The critical current performance of this conductor was experimentally investigated by using a short conductor sample. The results show that the critical current achieves the expected, resulting in demonstrating the validity of the fabrication method. The thermal strain is generally applied to the strands if SS conduit is used because of the different thermal expansion between the strands and SS conduit. However, it was not applied in our sample, since the conductor length, a few meters, is too short to keep it by friction force between the cable and conduit. The thermal strain applied to the strands in a long conductor is therefore estimated by using the solid model, in which the strain on the strands and conduit are calculated from the equilibrium of their thermal forces, ignoring the effect of cabling on relaxation of the strain on the strands. The results indicate that the Nb3Al strands are subjected to a compressive thermal strain of less than 0.4%. The critical current degradation by this is less than 10%, even though the SS conduit is used. Consequently, its critical current is estimated to be 90 kA, which is sufficiently high compared with the nominal, 46 kA, at 13 T and 4.5 K. Furthermore, it should be noted that the large thermal force, 80 kN, appears after the heat treatment at room temperature. (author)

2001-08-01

202

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

Science.gov (United States)

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.

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

2013-01-01

203

Vapor bubbles 'SUMO'  

CERN Document Server

We carry out a series of experiments with a special interest on growing and condensing processes of vapor bubble(s) injected into a subcooled pool. We examine effects of the degree of subcooling of the bulk in the pool and injection rate of the vapor into the pool. We pay their special attention to (i) abrupt collapse of the injected vapor bubble to form micrometer-scale bubbles, and (ii) interaction of adjacent vapor bubbles laterally injected to the pool through the orifices. We have found that a fine disturbance does arise on the surface of the vapor bubble just prior to its abrupt collapse. The bubble never exhibits an abrupt collapse without such instability over the free surface. In the case of the injection of a pair of vapor bubbles through the neighboring orifices, the interaction between the bubbles and the effects of the induced flows by the bubble behaviors control the surface dynamics. This fluid dynamics video introduces those phenomena.

Hosoya, Ryota

2010-01-01

204

Vapor spill monitoring method  

Energy Technology Data Exchange (ETDEWEB)

Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.

Bianchini, Gregory M. (Livermore, CA); McRae, Thomas G. (Livermore, CA)

1985-01-01

205

Calculation of a nonequilibrium gas-vapor-liquid screen using an h-d diagram  

Energy Technology Data Exchange (ETDEWEB)

A method for calculating a nonequilibrium gas-vapor-liquid thermal boundary layer using h-d diagrams is proposed. The parameters of the gas-vapor and liquid phases are calculated by using expressions for the wet-bulb temperature and vapor mass increase due to heat transfer between the liquid and the gas-vapor mixture. As an example, the mean temperatures of the gas-vapor and liquid phases are calculated for different conditions of heat transfer. 7 references.

Repukhov, V.M.; Podushko, V.S.

1987-01-01

206

Pressure drop characteristic in a cable-in-conduit conductor  

International Nuclear Information System (INIS)

A cable-in-conduit conductor (CICC) is the best candidate to satisfy requirement for a superconducting magnet to be employed in a fusion machine, such as a large operating current, high magnetic field, high breakdown voltage and so on. The present drop of the conductor is a key factor in design of a cryogenic pump to be used in a magnet system in the fusion machine. Also, pressure rise at a coil quench depends on the pressure drop characteristic of the conductor. Several workers investigated the pressure drop characteristic of CICCs. Katheder attempted to derive general correlation of the pressure drop characteristic basis on the correlation used for pebble beds. He compared his correlation with the measurements for the eight different CICCs. However, there is a large error of 75% in the maximum. It seems general formula of the pressure drop characteristic of CICC has not been provided. The authors investigate the pressure drop characteristic of 30 kA, 80 m cooling path length CICCs, whose dimension is almost same as the conductor to be employed in the fusion machine. The result indicates correlation between the Reynolds number and the friction factor of CICCs obeys the conventional formula for a smooth tube, Hagen-Poesuilli formula, in laminar flow region but does not agree with the conventional formula for a smooth tube, Blasius formula, in turbulent flow region. The experimental result is compared with Katheder's correlation. Katheder's correlation does not show good agreement with the experimental result in the turbulent flow region. The correlation that the friction factor is inversely proportional to 0.157 power of the Reynolds number and the proportional constant is 0.257 coincides better with the experimental result in this region. (author)

1995-01-01

207

Total arterial coronary revascularization-patient selection, stenoses, conduits, targets.  

Science.gov (United States)

Graft patency determines prognosis in coronary artery bypass grafting (CABG). Numerous reports over the past 20 years have documented superior patencies and prognosis when multiple arterial grafts are used, yet less than 10% of CABG have multiple arterial grafts. Several conduits have been proposed, with varying degrees of success. Saphenous vein grafts (SVG) begin to fail with intimal hypertrophy and then atheroma after 5 years, with patency rates of 50% to 60% at 10 years, and 95% at 10 years and >90% at 20 years. The radial artery is extremely versatile and can reach all territories, but is muscular and vulnerable to spasm and competitive flow. Similarly, the right gastroepiploic artery is also muscular, and is best suited to the posterior descending coronary artery, especially in reoperations and is also affected by competitive flow. In addition, bilateral internal thoracic artery grafting (BITA) grafts and total arterial revascularization (TACR) can be performed with identical perioperative mortality (1%) and perioperative morbidity to LITA + SVG. Importantly, survival is superior-85% to 90% at 10 years versus 75% to 80% respectively. BITA/TACR patients also suffer fewer late cardiac events and reoperations, with superior results for older patients, those requiring urgent surgery, diabetics, patients with renal dysfunction and in reoperations. Contraindications to BITA include obesity, insulin dependent diabetics, and severe chronic obstructive airways disease. As such, arterial grafts have better patencies and clinical results. BITA/TACR is often underutilized, but can be achieved in the majority of patients. Opportunities exist to enhance BITA/TACR use in CABG to the potential benefit of our patients. PMID:23977629

Tatoulis, James

2013-07-01

208

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

1994-01-01

209

Use new PLGL-RGD-NGF nerve conduits for promoting peripheral nerve regeneration  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Nerve conduits provide a promising strategy for peripheral nerve injury repair. However, the efficiency of nerve conduits to enhance nerve regeneration and functional recovery is often inferior to that of autografts. Nerve conduits require additional factors such as cell adhesion molecules and neurotrophic factors to provide a more conducive microenvironment for nerve regeneration. Methods In the present study, poly{(lactic acid-co-[(glycolic acid-alt-(L-lysine]} (PLGL was modified by grafting Gly-Arg-Gly-Asp-Gly (RGD peptide and nerve growth factor (NGF for fabricating new PLGL-RGD-NGF nerve conduits to promote nerve regeneration and functional recovery. PLGL-RGD-NGF nerve conduits were tested in the rat sciatic nerve transection model. Rat sciatic nerves were cut off to form a 10 mm defect and repaired with the nerve conduits. All of the 32 Wistar rats were randomly divided into 4 groups: group PLGL-RGD-NGF, group PLGL-RGD, group PLGL and group autograft. At 3 months after surgery, the regenerated rat sciatic nerve was evaluated by footprint analysis, electrophysiology, and histologic assessment. Experimental data were processed using the statistical software SPSS 10.0. Results The sciatic function index value of groups PLGL-RGD-NGF and autograft was significantly higher than those of groups PLGL-RGD and PLGL. The nerve conduction velocities of groups PLGL-RGD-NGF and autograft were significantly faster than those of groups PLGL-RGD and PLGL. The regenerated nerves of groups PLGL-RGD-NGF and autograft were more mature than those of groups PLGL-RGD and PLGL. There was no significant difference between groups PLGL-RGD-NGF and autograft. Conclusions PLGL-RGD-NGF nerve conduits are more effective in regenerating nerves than both PLGL-RGD nerve conduits and PLGL nerve conduits. The effect is as good as that of an autograft. This work established the platform for further development of the use of PLGL-RGD-NGF nerve conduits for clinical nerve repair.

Yan Qiongjiao

2012-07-01

210

Mechanisms of englacial conduit formation and their implications for subglacial recharge  

Science.gov (United States)

Ideas about the character and evolution of englacial drainage systems have been deeply influenced by the theoretical model developed by Shreve [1972. Movement of water in glaciers. Journal of Glaciology 11(62), 205-214]. The Shreve model is based on three main assumptions: (1) englacial drainage is in steady state; (2) englacial water will flow along the steepest hydraulic gradient within the glacier; and (3) pressure head equals the pressure of the surrounding ice minus a small component due to melting of the walls. The Shreve model has been widely adopted as a fundamental component of englacial drainage theory. There is no evidence, however, that the model provides a realistic picture of actual glacial drainage systems. To evaluate Shreve's theory, we used speleological techniques to directly survey englacial conduits. We mapped a total of 8.25 km of passage in 27 distinct englacial conduits in temperate, polythermal, cold-based and debris-covered glaciers between 2005 and 2008. New information reported here is supplemented by published data on 40 other englacial conduits located worldwide and surveyed to ice depths of 176 m using speleological techniques. In all cases, englacial drainage systems consisted of a single unbranching conduit. Englacial conduit morphologies were found to be intimately linked to the orientation of a glacier's principal stresses or the presence of pre-existing lines of high hydraulic conductivity. If a sufficient supply of water is available, hydrofracturing forms vertical conduits in zones of longitudinal extension and subhorizontal conduits where longitudinal stresses are compressive. On unfractured glacier surfaces, relatively shallow subhorizontal conduits with migrating nickpoints form by cut-and-closure provided channel incision is significantly faster than surface lowering. Conduits can also form along permeable debris-filled crevasse traces that connect supraglacial lake basins of different potential. Our results suggest that Shreve-type englacial drainage systems do not exist and implies that englacial conduits can only penetrate through thick ice to recharge the bed where supraglacial water bodies either intersect, or are advected through, zones of acceleration.

Gulley, J. D.; Benn, D. I.; Screaton, E.; Martin, J.

2009-09-01

211

Archimedes Mass Filter Vaporizer  

Science.gov (United States)

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

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

2001-10-01

212

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

Directory of Open Access Journals (Sweden)

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.

Fitremann J. -M.

2006-11-01

213

Mean Entropies  

CERN Document Server

Entropies must correspond to mean values for them to be measurable. The Shannon entropy corresponds to the weighted arithmetic mean, whereas the Renyi entropy corresponds to the exponential mean. These means refer to code lengths, which are converted into entropies by replacing the length of a sequence by the negative logarithm of the probability of its occurrence. Only affine and exponential generating functions of means preserve the property of additivity and invariance under translations, and hence are Kolmogorov-Nagumo functions, resulting in the Shannon and Renyi entropies, respectively. Pseudo-additive entropies are generating functions of means of order 0\\le\\tau<1, which is the exponential Renyi entropy, or, in the \\tau=0 limit, the Shannon entropy. Means of any order cannot be expressed as escort averages because such averages contradict the fact that the means are monotonically increasing functions of their order. Exponential mean error functions of Renyi, in general, and Shannon, in particular, a...

Lavenda, B H

2004-01-01

214

Investigating degassing dynamics into the shallow conduit through decompression experiments  

Science.gov (United States)

The history of bubbles' growth and interaction, as well as their spatial distribution in the shallow conduit, is deeply interconnected with the style of the eruptions. According to the fundamental role played by volatiles in the eruptive process, more effort is required in determining how the key factors of volcanic systems (i.e., magma properties, decompression rate) influence the dynamics of degassing. Therefore, our aim is to provide, through the analysis of decompression experiments on analogue materials, insights on such relations. We performed several decompression experiments with a shock-tube apparatus, and using silicon oil as laboratory-analogue for the magmatic melt. The sample was placed in a transparent autoclave, saturated with Argon for an established amount of time under a fixed pressure (up to a maximum of 10 MPa). Successively it was decompressed to atmospheric conditions, by releasing gas through a control valve. The dynamics of gas exsolution processes were recorded by using pressure sensors and a high speed camera. A range of viscosity values (1, 10, 100, 1000 Pa s) was investigated, for the same decompression path. Furthermore, some experiments were carried out with the addition of glass beads, as analogue to crystals, to the pure liquid. The height of the expanding column was monitored, in conjunction with images recorded during the experiments, and the growth rate of bubbles was measured at different times and depth. Finally, bubble size distribution has been evaluated at various stages for some experiments, in order to achieve a spatial map of the ongoing degassing phenomena. Results allowed us to define different regimes occurring during the decompression, whose features and characteristics are strongly affected by fluid viscosity. Indeed, several degassing phases were observed, from bubbly fluid to the eventual buildup of a more or less "foamy" phase, which ultimately experiences periodical oscillations around an average equilibrium level. Such periodic fluctuations, whose intensity and frequency depend on the experimental conditions, are triggered by bubbles bursting at the surface and mostly promoted by coalescence. Furthermore, an order of magnitude increase in the radial expansion velocity has been observed, as the nucleation front moves downward, during the experiment.

Spina, Laura; Scheu, Bettina; Cimarelli, Corrado; Dingwell, Donald

2014-05-01

215

Simultaneous apicoaortic conduit placement and mitral valve replacement in an adolescent with porcelain aorta, aortic stenosis, and mitral stenosis.  

Science.gov (United States)

We describe the treatment of a 16-year-old girl with calcific aortic stenosis, porcelain aorta, and calcific mitral stenosis with insufficiency using a valved apicoaortic conduit and mitral valve prosthesis. Both valve replacements were porcine bioprostheses, and the apicoaortic conduit was implanted without the use of cardiopulmonary bypass. In cases in which the degree of aortic calcification pre-empts manipulation of the coronary ostia, an apicoaortic conduit may offer a viable solution to improve left ventricular outflow obstruction. PMID:19699941

Herrmann, Jeremy L; Ruzmetov, Mark; Rodefeld, Mark D; Hoyer, Mark H; Brown, John W

2009-09-01

216

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

Science.gov (United States)

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

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

2014-04-01

217

A cut-and-closure origin for englacial conduits in uncrevassed regions of polythermal glaciers  

Science.gov (United States)

On uncrevassed regions of polythermal glaciers, englacial conduits can form by incision of supraglacial stream channels followed by roof closure. The origin and evolution of examples in Longyearbreen, Svalbard, and Khumbu Glacier, Nepal, were determined by speleological survey. The development of perennial incised channels requires that incision is significantly faster than glacier surface ablation, and thus will be favoured by high meltwater discharges in combination with cool climatic conditions or thick debris cover. Incised canyons can become blocked by drifted winter snow, refrozen meltwater, ice rafting from non-local sources (allochthonous breccias) and roof collapses (autochthonous breccias). Conduit closure can also occur in response to ice creep, particularly at depth. Following isolation from the surface, englacial conduits continue to evolve by vadose incision down to local base level. In the case of Longyearbreen, incision allowed the channel to reach the glacier bed, but on Khumbu Glacier deep incision is prevented because an effectively impermeable terminal moraine provides a high base level for the glacier drainage system. During our period of observations, deeper parts of the Longyearbreen conduit became blocked by a combination of ice accumulation and creep, causing the stream course to be re-routed to higher levels. On that glacier, incision, blockage and upward re-routing are cyclic. We conclude that 'cut and closure' is the dominant mechanism of englacial conduit formation on uncrevassed regions of polythermal glaciers.

Gulley, J. D.; Benn, D. I.; Müller, D.; Luckman, A.

218

High speed turbogenerator for power recovery from fluid flow within conduit  

Energy Technology Data Exchange (ETDEWEB)

A high speed turbogenerator functionally combining, in one machine, an electrical generator and an expansion turbine. The electrical generator itself has a shaft supported on two bearings and the expansion turbine comprises an expander wheel overhung on the generator shaft and which rotates as a high pressure gas is let down in the expansion turbine to a lower pressure at a minimum predetermined flow rate and pressure drop. The shaft operates at speeds of about 6,000 rpm to 32,000 rpm, preferably at the higher end of such range, i.e. 20,000 to 24,000 rpm. The unit is sufficiently compact that a new use for the electrical generator is to modify the same such that the entire high speed turbogenerator is contained within the conduit carrying the gas to be let down in pressure and only electrical wires need be led through the conduit. The integrity of the conduit is thus retained to the extent possible and only a high pressure cable fitting extends through the conduit. In the preferred embodiment, the high speed turbogenerator is entirely fitted within a natural gas conduit in a gas distribution station, thereby achieving the pressure letdown and also obtaining useful electrical power.

Irvine, M. D.

1985-11-26

219

Development and performance test results of 50 kA vapor-cooled current lead for ITER  

International Nuclear Information System (INIS)

JAERI has developed 50 kA current leads for the International Thermonuclear Experimental Reactor (ITER). The Center Solenoid (CS) Model Coil program is under way by means of international collaboration in ITER-EDA. The CS model coil is being developed for ITER CS coil and is for demonstration for ITER construction. The performance test of the CS model coil will be carried out at the JAERI ITER common test facility (CTF). The current lead consists of the vertical lead and the connection lead. The vertical lead is a vapor-cooled type and has a cable-in-conduit geometry. The vertical lead was designed with a heat leak of 1.2 W/kA at a helium flow rate of 0.06 g/(s·kA). The measured heat leak satisfied the designed value. The connection lead was made from copper pipe soldered with NbTi superconducting wires. The pipe was stabilized by the superconducting wires and a cooling channel. The current lead was operated up to 60 kA. The design and the performance test results of 50 kA current leads are reported. The results meet the specifications for the CS model coil test and for the ITER real machine. (author)

1998-08-01

220

Piezoelectric trace vapor calibrator  

Science.gov (United States)

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 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 nonlinear behavior from the IMS measurement process.

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

2006-08-01

 
 
 
 
221

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 nonlinear behavior from the IMS measurement process

2006-08-01

222

Water vapor retrieval from OMI visible spectra  

Science.gov (United States)

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)'s OMI operational retrieval algorithm to derive the Slant Column Density (SCD) of water vapor from OMI measurements using the 430-480 nm spectral region after extensive 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).

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

2014-01-01

223

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)

1987-01-01

224

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

International Nuclear Information System (INIS)

In this paper the results of exposing two multimode silica core optical fibers to Co-60 gamma irradiation in a radiation shielded configuration 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. In 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 degrees C) using well defined, highly stable optical sources and detectors

1992-04-26

225

Impact of conduit geometry on the performance of typical particulate microchip packings.  

Science.gov (United States)

This work investigates the impact of conduit geometry on the chromatographic performance of typical particulate microchip packings. For this purpose, high-performance liquid chromatography (HPLC)/UV-microchips with separation channels of quadratic, trapezoidal, or Gaussian cross section were fabricated by direct laser ablation and lamination of multiple polyimide layers and then slurry-packed with either 3 or 5 microm spherical porous C8-silica particles under optimized packing conditions. Experimentally determined plate height curves for the empty microchannels are compared with dispersion coefficients from theoretical calculations. Packing densities and plate height curves for the various microchip packings are presented and conclusively explained. The 3 microm packings display a high packing density irrespective of their conduit geometries, and their performance reflects the dispersion behavior of the empty channels. Dispersion in 5 microm packings correlates with the achieved packing densities, which are limited by the number and accessibility of corners in a given conduit shape. PMID:19916548

Jung, Stephanie; Höltzel, Alexandra; Ehlert, Steffen; Mora, Jose-Angel; Kraiczek, Karsten; Dittmann, Monika; Rozing, Gerard P; Tallarek, Ulrich

2009-12-15

226

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

Directory of Open Access Journals (Sweden)

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.

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

227

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

Directory of Open Access Journals (Sweden)

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

A Sadeghpour-Tabaee

2007-07-01

228

Second Vapor-Level Sensor For Vapor Degreaser  

Science.gov (United States)

Second vapor-level sensor installed at lower level in vapor degreaser makes possible to maintain top of vapor at that lower level. Evaporation reduced during idle periods. Provides substantial benefit, without major capital cost of building new vapor degreaser with greater freeboard height.

Painter, Nance M.; Burley, Richard K.

1990-01-01

229

Collagen (NeuraGen(®)) nerve conduits and stem cells for peripheral nerve gap repair.  

Science.gov (United States)

Collagen nerve guides are used clinically for peripheral nerve defects, but their use is generally limited to lesions up to 3cm. In this study we combined collagen conduits with cells as an alternative strategy to support nerve regeneration over longer gaps. In vitro cell adherence to collagen conduits (NeuraGen(®) nerve guides) was assessed by scanning electron microscopy. For in vivo experiments, conduits were seeded with either Schwann cells (SC), SC-like differentiated bone marrow-derived mesenchymal stem cells (dMSC), SC-like differentiated adipose-derived stem cells (dASC) or left empty (control group), conduits were used to bridge a 1cm gap in the rat sciatic nerve and after 2-weeks immunohistochemical analysis was performed to assess axonal regeneration and SC infiltration. The regenerative cells showed good adherence to the collagen walls. Primary SC showed significant improvement in distal stump sprouting. No significant differences in proximal regeneration distances were noticed among experimental groups. dMSC and dASC-loaded conduits showed a diffuse sprouting pattern, while SC-loaded showed an enhanced cone pattern and a typical sprouting along the conduits walls, suggesting an increased affinity for the collagen type I fibrillar structure. NeuraGen(®) guides showed high affinity of regenerative cells and could be used as efficient vehicle for cell delivery. However, surface modifications (e.g. with extracellular matrix molecule peptides) of NeuraGen(®) guides could be used in future tissue-engineering applications to better exploit the cell potential. PMID:24792394

di Summa, Pietro G; Kingham, Paul J; Campisi, Corrado C; Raffoul, Wassim; Kalbermatten, Daniel F

2014-06-20

230

Sciatic nerve regeneration by cocultured Schwann cells and stem cells on microporous nerve conduits.  

Science.gov (United States)

Cell transplantation is a useful therapy for treating peripheral nerve injuries. The clinical use of Schwann cells (SCs), however, is limited because of their limited availability. An emerging solution to promote nerve regeneration is to apply injured nerves with stem cells derived from various tissues. In this study, different types of allogeneic cells including SCs, adipose-derived adult stem cells (ASCs), dental pulp stem cells (DPSCs), and the combination of SCs with ASCs or DPSCs were seeded on nerve conduits to test their efficacy in repairing a 15-mm-long critical gap defect of rat sciatic nerve. The regeneration capacity and functional recovery were evaluated by the histological staining, electrophysiology, walking track, and functional gait analysis after 8 weeks of implantation. An in vitro study was also performed to verify if the combination of cells led to synergistic neurotrophic effects (NGF, BDNF, and GDNF). Experimental rats receiving conduits seeded with a combination of SCs and ASCs had the greatest functional recovery, as evaluated by the walking track, functional gait, nerve conduction velocity (NCV), and histological analysis. Conduits seeded with cells were always superior to the blank conduits without cells. Regarding NCV and the number of blood vessels, conduits seeded with SCs and DPSCs exhibited better values than those seeded with DPSCs only. Results from the in vitro study confirmed the synergistic NGF production from the coculture of SCs and ASCs. It was concluded that coculture of SCs with ASCs or DPSCs in a conduit promoted peripheral nerve regeneration over a critical gap defect. PMID:23192007

Dai, Lien-Guo; Huang, Guo-Shiang; Hsu, Shan-hui

2013-01-01

231

The role of shear heating in obsidian formation within volcanic conduits  

Science.gov (United States)

While most volcanic rocks contain a significant amount of crystals (15-35 vol%), obsidian is unusual because it contains Poiseuille solutions. These temperature increases are 150-200 K higher than those found by existing numerical models that account for shear heating in volcanic conduits. Based on velocities in the outer edge of the conduit, residence times of crystals in hotter magma range from 6 minutes to 58 days in a 1 km conduit; longer conduits increase residence time. Furthermore, complex conduit geometry can cause separation of laminar flow lines which would distribute hotter magma to other parts of the conduit. Longer residence times and higher temperatures favor crystal resorption. Modal analyses of obsidian in this study reflect a regional lack of quartz and sanidine phenocrysts in eastern California obsidian. This regional lack is unpredicted by the dominant hypotheses of obsidian formation and unexpected based on the mineralogy of other high-silica rhyolites. Phenocryst morphologies are dominantly rounded in crystal-poor obsidian, but not in crystal-rich obsidian (>2 vol% phenocrysts). Decompression is thought to cause quartz resorption during magma ascent, causing disequilibrium rounding and embayments in quartz. However, decompression does not account for the lack of sanidine in crystal-poor obsidian. Sanidine is stable in pre-eruptive conditions in some obsidian magmas, but experiments show that it is unstable at high-temperature, 1 atm conditions. Near-surface thermal disequilibrium caused by shear heating could dissolve unstable sanidine phenocrysts and cause rounding in other phenocrysts. By increasing temperatures to near liquidus conditions, shear heating potentially plays a large role in the formation of obsidian by inhibiting crystallization and resorbing existing crystals.

Curry, A. C.

2013-12-01

232

Small scale high resolution LiDAR measurements of a subglacial conduit  

Science.gov (United States)

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.

Mankoff, K. D.; Gulley, J.

2012-04-01

233

Macrofouling in the cooling water conduits of a coastal power station  

International Nuclear Information System (INIS)

Macrofouling incidence at six different locations experiencing different environmental conditions in the cooling conduits of the Madras Atomic Power Station (MAPS) was studied. Samples were analyzed for biomass and species abundance. Fouling biomass was significantly (t=3.95, P=0.0016) higher on concrete surface than on carbon steel surface. Flow velocity, temperature and substratum type were the main factors which determined community structure in different sections of the cooling conduits. These factors as well as the fouling control regime adopted in cooling systems make fouling more intense in some places than in others. (author)

1997-09-01

234

Transient heat transfer from a cable in conduit configuration in subcooled he I and he II  

International Nuclear Information System (INIS)

Experimental investigations of liquid helium heat transfer from a model of a cable in conduit conductor are reported. The model consists of a 19 element stainless steel tubing bundle contained within a rectangular cross section conduit. The experiment involves resistively heating the bundle with a constant amplitude heat pulse, while recording the time variation of the temperature within the conductors and helium. Three test sections were studied each having a different spacing between the elements, delta. Results reported here are for bath temperatures 4.2, 2.5 and 1.8 K with applied pressure p = 100 kPa (1 atm)

1985-03-01

235

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)

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.

Line A.

2006-11-01

236

Directed vapor deposition  

Science.gov (United States)

This dissertation describes the invention, design, construction, experimental evaluation and modeling of a new physical vapor deposition technique (U.S. Patent #5,534,314) for high rate, efficient deposition of refractory elements, alloys, and compounds onto flat or curved surfaces. The new Directed Vapor Deposition (DVD) technique examined in this dissertation was distinct from previous physical vapor deposition techniques because it used low vacuum electron beam (e-beam) evaporation in combination with a carrier gas stream to transport and vapor spray deposit metals, ceramics, and semiconducting materials. Because of the system's unique approach to vapor phase materials processing, detailed analyses of critical concepts (e.g. the e-beam accelerating voltage and power required for evaporation, the vacuum pumping capacity necessary to generate specific gas flow velocities exiting a nozzle) were used to reduce to practice a functioning materials synthesis tool. After construction, the ability to create low contamination films of pure metals, semi-conducting materials, and compounds via this new method was demonstrated, and oxide deposition using an oxygen-doped gas stream in combination with a pure metal evaporant source was shown to be feasible. DVD vapor transport characteristics were experimentally investigated with deposition chamber pressure, carrier gas type, and e-beam power being identified as major processing parameters which affected vapor atom trajectories. The low vacuum carrier gas streams employed in DVD showed a dramatic ability to focus the vapor stream during transport to the substrate and thereby enhance material deposition rates and efficiencies significantly under certain process conditions. Conditions for maximum deposition efficiency onto flat substrates and continuous fibers were experimentally identified by varying chamber pressure, carrier gas velocity (Mach number), and e-beam power. Deposition efficiencies peaked at about 0.5 Torr when coating flat or fibrous substrates. Higher Mach numbers led to higher efficiencies below the efficiency peak, but above the peak this Mach number trend reversed. Increasing e-beam power decreased the magnitude of the deposition efficiency peak and shifted it to higher chamber pressures. Fiber coating experiments revealed a maximum deposition efficiency over twice the level expected for pure line-of-sight deposition, and scanning electron microscopy revealed that, for conditions of maximum efficiency, vapor was depositing simultaneously on the front of the fiber facing the incoming vapor and on the fiber's sides and back. The vapor transport and deposition trends appeared to result from vapor atom collisions with gas atoms in the carrier flow, collisions which affected vapor atom form (single atom or clusters), location in the flow, and interaction with the substrate (leading to line and non-line-of-sight coating). Atomic vapor transport in DVD was investigated using Direct Simulation Monte Carlo (DSMC) methods and biatomic collision theory (BCT). For atoms transported to a flat surface perpendicular to the vapor-laden carrier gas stream, the velocity vector during transport and impact location were calculated, making possible determination of adatom deposition efficiency, spatial distribution, impact energy, and incident angle with the substrate. Model results compared favorably with random walk predictions, independent experimental data of sputter atom energy loss, and low e-beam power experimental results. The model suggested that the atoms deposited in a DVD process had a low impact energy (< 0.1 eV) and a broad incident angular distribution with the substrate. The DSMC and BCT models were used to design an improved DVD system with significantly enhanced deposition efficiency.

Groves, James Frederick

237

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

Science.gov (United States)

Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral occurs among the pyroxenes/amphiboles. The content of titanium in the iron ores changes from 0.14% to 0.20 wt. % gradually from southeast to northwest (NW), suggesting the direction of melt-fluid flow bearing iron is from SE to NW. These characteristics in the Xishimen iron deposit indicate that melt-fluid flow bearing iron controls the distribution of iron orebodies. Several key points in 'Magmatic Conduit Metallogenic System' are concluded here: 1. All melt or melt-fluid bearing metals formed in the staging chamber are finally settled in the conduits based on their differences in density; 2. We can determine the direction of the melt or melt-fluid flow according to the content and textures of ores in the conduits. We propose that 'Magmatic Conduit Metallogenic System' could serve as a new exploring model for the ore-deposits connected with intrusions.

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

2013-12-01

238

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

Science.gov (United States)

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.

Perrin, Jérôme; Luetscher, Marc

2008-08-01

239

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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.

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.

240

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

Directory of Open Access Journals (Sweden)

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.

Cláudio A Salles

1992-06-01

 
 
 
 
241

Cooking system with closed loop heat transfer means  

Energy Technology Data Exchange (ETDEWEB)

A cooking system is described comprising a cooking element for receiving food to be cooked; heat generating means; a sealed closed loop circuit; the closed loop circuit including a heating and vaporization zone, the heat generating means comprising a gaseous fuel fired radiant burner, and the heating and vaporization zone.

Scherer, R.M.

1987-04-28

242

Laparoscopic management of a small bowel herniation from an ileal conduit: report of a case and review of the literature.  

Science.gov (United States)

Bladder carcinoma can be treated with cystectomy and urinary diversion. Ileal conduit is a popular technique, originally performed with closure of all mesenteric and peritoneal defects to minimize internal herniation. Recent advances in laparoscopic and robotic techniques often leave these defects open. We present a case of a 75-year-old gentleman with a small bowel entrapment underneath an intraperitoneal ileal conduit and ureter causing obstruction. This internal hernia occurred 2 months after undergoing a DaVinci robotic-assisted laparoscopic cystoprostatectomy with an ileal conduit. Bowel obstruction is an important complication associated with the need for reoperation and patient mortality. Historical review shows a precedent for closure of the mesenteric defect, obliterating the peritoneal defect in the right lumbar gutter, and suturing the ileal conduit to the posterior peritoneum to prevent potential internal hernias. The literature involving ileal conduits is examined for consensus on the preferred method of treating these potential spaces. PMID:23579536

Coughlin, Lisa M; Orr, Dennis P

2013-04-01

243

What Does the Mean Mean?  

Science.gov (United States)

The arithmetic mean is a fundamental statistical concept. Unfortunately, social science students rarely develop an intuitive understanding of the mean and rely on the formula to describe or define it. According to constructivist pedagogy, educators that have access to a variety of conceptualizations of a particular concept are better equipped to…

Watier, Nicholas N.; Lamontagne, Claude; Chartier, Sylvain

2011-01-01

244

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

LENUS (Irish Health Repository)

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.

Murphy, Darra T

2011-02-01

245

Percutaneous Transthoracic Computed Tomography-Guided AICD Insertion in a Patient with Extracardiac Fontan Conduit  

International Nuclear Information System (INIS)

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.

2011-02-01

246

De novo fenestration of extra-cardiac Fontan Goretex conduit assisted by Inoue balloon.  

Science.gov (United States)

De novo fenestration of Goretex conduit of extra-cardiac total cavopulmonary connection in the postoperative period is challenging, and is rarely reported. We report a 17-year-old boy with failing Fontan circuit in whom fenestration was created, aided by an Inoue balloon. PMID:23172624

Gupta, Saurabh Kumar; Ramakrishnan, Sivasubramanian; Kothari, Shyam S

2013-12-01

247

Transient and asymptotic dispersion in confined sphere packings with cylindrical and non-cylindrical conduit geometries.  

Science.gov (United States)

We study the time and length scales of hydrodynamic dispersion in confined monodisperse sphere packings as a function of the conduit geometry. By a modified Jodrey-Tory algorithm, we generated packings at a bed porosity (interstitial void fraction) of ?=0.40 in conduits with circular, rectangular, or semicircular cross section of area 100?d(p)(2) (where d(p) is the sphere diameter) and dimensions of about 20d(p) (cylinder diameter) by 6553.6d(p) (length), 25d(p) by 12.5d(p) (rectangle sides) by 8192d(p) or 14.1d(p) (radius of semicircle) by 8192d(p), respectively. The fluid-flow velocity field in the generated packings was calculated by the lattice Boltzmann method for Péclet numbers of up to 500, and convective-diffusive mass transport of 4×10(6) inert tracers was modelled with a random-walk particle-tracking technique. We present lateral porosity and velocity distributions for all packings and monitor the time evolution of longitudinal dispersion up to the asymptotic (long-time) limit. The characteristic length scales for asymptotic behaviour are explained from the symmetry of each conduit's velocity field. Finally, we quantify the influence of the confinement and of a specific conduit geometry on the velocity dependence of the asymptotic dispersion coefficients. PMID:21576163

Khirevich, Siarhei; Höltzel, Alexandra; Tallarek, Ulrich

2011-06-28

248

Characterisation and modelling of conduit restricted karst aquifers – Example of the Auja spring, Jordan Valley  

Science.gov (United States)

Complex recession behaviour caused by flow threshold and conduit–matrix cross-flow.Spring hydrograph and recession analysis of long-term and high-resolution time series.Simulation of spring hydrograph with a non-linear reservoir model.Water balance modelling to assess groundwater recharge in a semi-arid karst area.

Schmidt, Sebastian; Geyer, Tobias; Guttman, Joseph; Marei, Amer; Ries, Fabian; Sauter, Martin

2014-04-01

249

Effect of strand diameter on the stability of the cable-in-conduit conductor  

Energy Technology Data Exchange (ETDEWEB)

In the proto-toroidal program in Japan Atomic Energy Research Institute (JAERI) whose purpose was the development of 30 kA-12 T scale forced-cooled superconductors for the toroidal coils of the fusion machines, many kinds of research and development work were planned and have been performed from the standpoint of engineering. As one of them, this experimental work reported here was designed and carried out to investigate the stability performance of the cable-in-conduit type conductor placing the focus on its dependency on the strand diameter. Effect of strand diameter on the stability of the cable-in-conduit type superconductor was investigated experimentally. The cable-in-conduit type conductor is widely adopted in the design of large superconducting magnets and its properties have been studied. Present experiment was planned and performed to clarify the relation between the stability and the strand diameter or cooling perimeter. As a result of a series of present experiment, it was confirmed that the recovery capacity of the cable-in-conduit type superconductor from the normal transition was in proportion to the cooling perimeter of the cable.

Nishi, M.; Armstrong, J.R.; Koizumi, N. (Japan Atomic Energy Research Inst., Ibaraki (Japan)) (and others)

1994-07-01

250

The formation of boundary waves in closed conduits with sediment transported  

Science.gov (United States)

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.

Hiratsuka, Tomofumi; Izumi, Norihiro

251

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

Science.gov (United States)

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. ?? 2011 The Author(s). Ground Water ?? 2011, National Ground Water Association.

Reimann, T.; Birk, S.; Rehrl, C.; Shoemaker, W. B.

2012-01-01

252

Alternative Fuels Compatibility with Army Equipment Testing - Aged Niedner Rifts Conduit Testing.  

Science.gov (United States)

The objective of this project was to perform burst and cyclic testing on an aged Niedner RIFTS conduit from Fort Lee, and then compare these results with the unaged baseline results from Niedner RIFTS testing performed by SwRI in 2006. Burst testing is us...

B. R. Wright O. P. Harrison

2012-01-01

253

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

Science.gov (United States)

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

Nzegwu, Azuka

2010-01-01

254

Effect of Weight and Compensation Loads on the Deformation of a Steam Conduit  

International Nuclear Information System (INIS)

The effect of hoop strain over the pipe perimeter and changes in the diameters of the cross section under long-term loading of the steam conduit due to the internal pressure and bending moment are considered. It is shown that the bending moment can be evaluated by measuring the residual strain of the pipe

2003-03-01

255

Development of high strength austenitic stainless steel for conduit of Nb3Al conductor  

International Nuclear Information System (INIS)

Japan Atomic Energy Research Institute (JAERI) started developing new austenitic stainless steel for a conduit (1 - 2 mm) of a Nb3Al conductor in collaboration with Nippon Steel Corporation (NSC). A high strength austenitic stainless steel is required for a conduit of a Nb3Al conductor to make the best use of superconducting properties of a Nb3Al conductor. JAERI and NSC successfully developed the high strength austenitic stainless steel, JN1 (YS ? 1,300 MPa, KIc ? 200 MPa?m at 4K) for magnet structures having thick section. However, JN1 is not suitable for a conduit material because elongation of JN1 decreases to less than 10 % due to sensitization during reaction heat treatment for Nb3Al. Therefore, modification of JN1 was performed as a first step to develop a new conduit material which withstands Nb3Al reaction heating. Small trial lots heat-treated at 973 - 1173 K for 2 - 200 hours were prepared and evaluated by Charpy impact test and tensile test at 77 K and 4K. A material having yield strength of 1,390 MPa and elongation of 34 % after aging at 973 K x 200 h are developed up to now. This paper describes requirements on the mechanical properties and status of the development work. In addition, empirical equations to predict 4K yield strength, elongation, and Charpy absorbed energy from 77K data are proposed in this paper

1995-07-17

256

Effect of strand diameter on the stability of the cable-in-conduit conductor  

International Nuclear Information System (INIS)

In the proto-toroidal program in Japan Atomic Energy Research Institute (JAERI) whose purpose was the development of 30 kA-12 T scale forced-cooled superconductors for the toroidal coils of the fusion machines, many kinds of research and development work were planned and have been performed from the standpoint of engineering. As one of them, this experimental work reported here was designed and carried out to investigate the stability performance of the cable-in-conduit type conductor placing the focus on its dependency on the strand diameter. Effect of strand diameter on the stability of the cable-in-conduit type superconductor was investigated experimentally. The cable-in-conduit type conductor is widely adopted in the design of large superconducting magnets and its properties have been studied. Present experiment was planned and performed to clarify the relation between the stability and the strand diameter or cooling perimeter. As a result of a series of present experiment, it was confirmed that the recovery capacity of the cable-in-conduit type superconductor from the normal transition was in proportion to the cooling perimeter of the cable

1994-07-01

257

Finite element modeling of self-potential signals over conduits and fractures in covered karst terrain Peter Bumpus and Sarah Kruse  

Science.gov (United States)

A year of continuous monitoring with two grids of 12-15 electrodes each measured self-potential (SP) over two small covered-karst conduits in Tampa, Florida. Positive and negative SP anomalies episodically manifested over conduits, suggesting that conduit flow is dynamic, not static. Various SP flow regimes in the conduits are postulated: flow in the conduit is faster than through surrounding surficial sediment, flow in the conduit is slower than through surrounding sediment, and conduit flow rates match those through the surrounding sediments. It is further postulated that conduits change permeability with inflow and washing out of sediment, especially associated with rain events. Numerical simulations of the postulated flow regimes were run with 2D simulations using the Comsol finite element modeling code. Simulations show that each regime produces different SP patterns. Models simulate the Tampa field setting in which a 1-2 meter-thick high permeability sand layer overlies a low-permeability clay-rich layer. A funnel-shaped conduit breaches both layers. In the models, when the permeability of the conduit sands is equal to surrounding surficial sands, a small (several mV) negative anomaly manifests locally at the conduit. This negative anomaly can be explained as the result of the depression of the SPS surface (the first sediment surface with a change in conductance or streaming potential coefficient) in the conduit. However a permeability difference of as little as 5 to 20 percent between conduit and background can cause an SP anomaly of tens to several hundred millivolts, either positive or negative. When the permeability is higher in the conduit than the surficial sands, lateral flow into the conduit within the sand layer and through the conduit to the underlying aquifer are both high, and the SP signal over the conduit is positive. This may contradict the concept exemplified in other studies that downward flow creates a negative anomaly. In our case the positive voltage is the result of high lateral flow toward a high flux conduit. As a result, the horizontal dimension of the conduit plays a role in whether a positive or negative anomaly is observed locally near the surface, depending on the degree to which the terminus of the inward lateral flow affects voltage over the conduit center. When the conduit has lower permeability than surrounding surficial sediment, models show that the SP anomaly is negative. In this case lateral flow is small to a low-flux conduit and there is little build-up of positive SP to overcome the negative potential associated with the SPS trough.

Bumpus, P. B.; Kruse, S. E.

2013-12-01

258

Vapor pressures and enthalpies of vaporization of azides  

Energy Technology Data Exchange (ETDEWEB)

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.

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

259

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.

2011-11-01

260

Impact of conduit geometry and bed porosity on flow and dispersion in noncylindrical sphere packings.  

Science.gov (United States)

The three-dimensional velocity field and corresponding hydrodynamic dispersion in pressure-driven flow through fixed beds of solid (impermeable), uniformly sized, spherical particles are studied by quantitative numerical analysis for conduits with different cross-sectional geometries. Packings with average interparticle porosities (bed porosities) of 0.40 < or = epsilon < or = 0.50 were generated in conduits with circular, quadratic, rectangular, and semicircular cross sections utilizing a parallel collective-rearrangement algorithm. The lateral dimensions of the generated packings were chosen to represent typical values encountered in miniaturized liquid chromatography (LC) systems. The interparticle velocity field was calculated using the lattice-Boltzmann (LB) method, and a random-walk particle-tracking method was employed to model advective-diffusive transport of an inert tracer in the LB velocity field. We present the morphologies and corresponding flow patterns for these packings and demonstrate that the porosity distribution and velocity profiles of noncylindrical packings deviate significantly from those of conventional cylindrical packings. This deviation becomes more pronounced at higher bed porosities. Extended regions of high local porosity in the corners of noncylindrical conduits give rise to the formation of fluid channels of advanced flow velocity. The differences in the flow velocity distributions of cylindrical and noncylindrical packings are analyzed, and their impact on the axial hydrodynamic dispersion coefficient is shown. The presented data support the conclusion that LC performance depends critically on the conduit geometry and bed porosity. Our results have particular relevance for microchip-LC, where noncylindrical conduit geometries are prevalent. PMID:17985846

Khirevich, Siarhei; Höltzel, Alexandra; Hlushkou, Dzmitry; Tallarek, Ulrich

2007-12-15

 
 
 
 
261

Flowmeter for determining average rate of flow of liquid in a conduit  

Energy Technology Data Exchange (ETDEWEB)

This invention is a compact, precise, and relatively simple device for use in determining the average rate of flow of a liquid through a conduit. The liquid may be turbulent and contain bubbles of gas. In a preferred embodiment, the flowmeter includes an electrical circuit and a flow vessel which is connected as a segment of the conduit conveying the liquid. The vessel is provided with a valved outlet and is partitioned by a vertical baffle into coaxial chambers whose upper regions are vented to permit the escape of gas. The inner chamber receives turbulent downflowing liquid from the conduit and is sized to operate at a lower pressure than the conduit, thus promoting evolution of gas from the liquid. Lower zones of the two chambers are interconnected so that the downflowing liquid establishes liquid levels in both chambers. The liquid level in the outer chamber is comparatively calm, being to a large extent isolated from the turbulence in the inner chamber once the liquid in the outer chamber has risen above the liquid-introduction zone for that chamber. Lower and upper probes are provided in the outer chamber for sensing the liquid level therein at points above its liquid-introduction zone. An electrical circuit is connected to the probes to display the time required for the liquid level in the outer chamber to successively contact the lower and upper probes. The average rate of flow through the conduit can be determined from the above-mentioned time and the vessel volume filled by the liquid during that time.

Kennerly, John M. (Knoxville, TN); Lindner, Gordon M. (Oak Ridge, TN); Rowe, John C. (Oak Ridge, TN)

1982-01-01

262

Tile drainage as karst: Conduit flow and diffuse flow in a tile-drained watershed  

Science.gov (United States)

The similarity of tiled-drained watersheds to karst drainage basins can be used to improve understanding of watershed-scale nutrient losses from subsurface tile drainage networks. In this study, short-term variations in discharge and chemistry were examined from a tile outlet collecting subsurface tile flow from a 963 ha agricultural watershed. Study objectives were to apply analytical techniques from karst springs to tile discharge to evaluate water sources and estimate the loads of agricultural pollutants discharged from the tile with conduit, intermediate and diffuse flow regimes. A two-member mixing model using nitrate, chloride and specific conductance was used to distinguish rainwater versus groundwater inputs. Results indicated that groundwater comprised 75% of the discharge for a three-day storm period and rainwater was primarily concentrated during the hydrograph peak. A contrasting pattern of solute concentrations and export loads was observed in tile flow. During base flow periods, tile flow consisted of diffuse flow from groundwater sources and contained elevated levels of nitrate, chloride and specific conductance. During storm events, suspended solids and pollutants adhered to soil surfaces (phosphorus, ammonium and organic nitrogen) were concentrated and discharged during the rapid, conduit flow portion of the hydrograph. During a three-day period, conduit flow occurred for 5.6% of the time but accounted for 16.5% of the total flow. Nitrate and chloride were delivered primarily with diffuse flow (more than 70%), whereas 80-94% of total suspended sediment, phosphorus and ammonium were exported with conduit and intermediate flow regimes. Understanding the water sources contributing to tile drainage and the manner by which pollutant discharge occurs from these systems (conduit, intermediate or diffuse flow) may be useful for designing, implementing and evaluating non-point source reduction strategies in tile-drained landscapes. ?? 2007 Elsevier B.V. All rights reserved.

Schilling, K. E.; Helmers, M.

2008-01-01

263

Water vapor in the continental atmosphere  

Science.gov (United States)

The data of long-term (1980 - 2000) continuous spectroscopic measurements of total water vapor content in the column of the continental atmosphere (the Issyk Kul station, the center of Eurasia) are given. The amplitudes and phases of water vapor seasonal variations have been defined, their long-term values and seasonal differences of the gas content variability are given for the observation site depending on the atmospheric temperature. A year-to-year variability of atmospheric total water vapor content is stated under a linear approximation that corresponds to an annual increase of its content by 0.015 g./cm2. With the help of the spectral analysis of the data the main periodic components of water vapor variability were revealed with the periods of 6, 12, 35, 51 and 110 months. Their connection is shown with the temperature seasonal variations (periods of 6 and 12 months), with the El Nino phenomenon global consequences (a 51 month period) and with powerful volcanic eruptions (periods of 35, 51 and 110 months). An empirical statistical model was constructed for the atmospheric water vapor variability, that describes its mean monthly contents with an error of +/- 13%.

Aref'ev, Vladimir N.; Kamenogradsky, N. Y.; Kashin, F. V.; Ustinov, V. P.; Semyonov, V. K.; Sinyakov, V. P.; Sorokina, L. I.

2002-03-01

264

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

Directory of Open Access Journals (Sweden)

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

Tymokhina Elizaveta

2012-07-01

265

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 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

2009-04-01

266

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)

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.

Colbourne, Jason

1999-01-01

267

BTSC VAPOR INSTRUSION PRIMER "VAPOR INTRUSION CONSIDERATION FOR REDEVELOPMENT"  

Science.gov (United States)

This primer is designed for brownfields stakeholders concerned about vapor intrusion, including property owners, real estate developers, and contractors performing environmental site investigations. It provides an overview of the vapor intrusion issue and how it can impact the ap...

268

Water vapor in protoplanetary disks  

Science.gov (United States)

This thesis is devoted to a study of the conditions and evolution of the planet formation region in young circumstellar disks, by means of spectroscopic observations of molecular gas emission. The main focus of this work is the infrared spectrum of water (H2O), which provides thousands of emission lines tracing the warm and dense gas inward of the water snow line in disks. The analysis includes also emission from some organic molecules that trace the carbon chemistry, C2H2, HCN, and CO2, as well as emission from OH that is connected to the formation and destruction of the water molecule. Two are the main directions explored in this work, for which we used spectra from the Spitzer Space Telescope (IRS) and the Very Large Telescope (VISIR and X-shooter). The first is to investigate how variable accretion phenomena occurring during the T Tauri phase affect the molecular environments in the planet formation region of disks. By monitoring T Tauri stars in different phases of accretion, we found that outbursts can remarkably affect their mid-infrared molecular emission. We propose a scenario where accretion flares trigger a recession of the water snow line, increasing water emission from the disk, when the accretion luminosity keeps higher over long enough timescales for the thermal structure of the disk to change (at least a few weeks, as observed in the strongly variable EX Lupi). In addition, enhanced UV radiation is found to produce OH from photodissociation of water in the disk. Organic molecules instead disappear during a strong outburst, and we are currently investigating the long-term evolution of these effects. A second direction was taken to tackle another fundamental problem: the origin of water vapor in inner disks. Some models predict that water is produced by evaporation of icy solids migrating inward of the snow line. One way to probe this scenario is by measuring the abundance of water vapor in the inner disk, and compare it to the oxygen abundance available to form water in situ. In this thesis, for the first time, a systematic rotation diagram analysis has been applied to infrared water emission. This analysis established a link between the spread of the rotational scatter and the water abundance in the inner disk, where a large rotational scatter would provide evidence for the migration scenario. Large rotational scatters are indeed tentatively observed in some disks, supporting water vapor enrichment from evaporation of icy migrators. Future higher-resolution observations will provide important answers on the origin of water vapor and its connection to disk evolution and planet formation processes.

Banzatti, Andrea

2013-03-01

269

Nerve conduits based on immobilization of nerve growth factor onto modified chitosan by using genipin as a crosslinking agent.  

Science.gov (United States)

Incorporation of nerve growth factor (NGF) into a nerve conduit can improve peripheral nerve regeneration. Here, genipin, a natural and low toxic agent, was used to crosslink chitosan, a natural polysaccharide, and concurrently to immobilize NGF onto modified chitosan, followed by fabrication of chitosan (CS)-genipin (GP)-NGF nerve conduits. MTT test showed that the cell viability of Schwann cells cultured in the conduit extract was not significantly different from that in plain medium. The neurite outgrowth measurement and immunocytochemistry with anti-growth-associated protein-43 and anti-neurofilament indicated that NGF released from CS-GP-NGF nerve conduits retained the bioactivity of stimulating neuronal differentiation of PC12 cells. Fracture strength measurements and vitamin B12 release analysis confirmed that CS-GP-NGF nerve conduits possessed good mechanical properties and adequate permeability. We also investigated the in vitro release kinetics of NGF from CS-GP-NGF nerve conduits by ELISA. The continuous release profile of NGF, within a 60-day time span, consisted of an initial burst that was controlled by a concentration gradient-driven diffusion, followed by a zero-order release that was controlled by a degradation of chitosan matrix. Collectively, CS-GP-NGF nerve conduits had an integrated system for continuous release of NGF, thus holding promise for peripheral nerve repair applications. PMID:21736941

Yang, Yumin; Zhao, Weijia; He, Jianghong; Zhao, Yahong; Ding, Fei; Gu, Xiaosong

2011-11-01

270

Heat of vaporization spectrometer  

Energy Technology Data Exchange (ETDEWEB)

Multilayer desorption measurements of various substances adsorbed on a stainless steel substrate are found to exhibit desorption profiles consistent with a zeroth order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification.

Edwards, D. Jr.

1978-01-01

271

Heat of vaporization spectrometer  

Energy Technology Data Exchange (ETDEWEB)

Multilayer desorption measurements of various substances adsorbed on a stainless-steel substrate are found to exhibit desorption profiles consistent with a zeroth-order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification.

Edwards, D. Jr.

1979-03-01

272

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

Science.gov (United States)

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

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

2011-01-01

273

How Mean is the Mean?  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we voice concerns about the uncritical manner in which the mean is often used as a summary statistic in psychological research. We identify a number of implicit assumptions underlying the use of the mean and argue that the fragility of these assumptions should be more carefully considered. We examine some of the ways in which the potential violation of these assumptions can lead us into significant theoretical and methodological error. Illustrations of alternative models of research already extant within Psychology are used to explore methods of research less mean-dependent and suggest that a critical assessment of the assumptions underlying its use in research play a more explicit role in the process of study design and review.

CraigSpeelman

2013-07-01

274

Textural evolution of a conduit margin witnessing the unusual explosivity of a basaltic Plinian eruption  

Science.gov (United States)

Basaltic Plinian eruptions are a rare phenomenon and are poorly understood. Here we investigate these unusual high-explosivity eruptions with detailed textural observations of their products. We have analysed marginal textures of a feeding conduit of the AD 1886 Tarawera fissure eruption through which a gas-ash-suspension was erupting for ~4-5 hours and examined strain markers of simple shear and evidence of heating. We quantified vesicle size distributions and vesicle orientations in the rhyolitic country rock of the Wahanga dome in contact with the mafic dyke. Shape anisotropy and density increases toward the margin, corresponding to a decrease in 2D vesicularity. Similarly, the margin-parallel deformation is manifested in cleaved and plastically deformed biotite crystals. The aspect ratio of biotite phenocrysts in the rhyolitic country rock increases toward the margin. In the undeformed country rock average aspect ratios are ~1-2, whereas in the marginal zone of 1-2 mm thickness values increase to >50. In the marginal zone an accumulation of low angles spanned by the conduit wall and the long axis of biotite phenocrysts is observed. Rotation of phenocrysts near the margin might be produced by simple shear from coupling of the erupting gas-ash-suspension. We measured major element profiles in the interstitial groundmass glass toward the conduit margin by EMPA. Proximal depletion of Na2O and enrichment of K2O suggest that the eruption was at high temperature for time sufficient for ~1 mm of concentration-gradient diffusion of mobile elements. The changes in porosity, texture and chemistry take place in a ~1-1.5 mm thick deformed zone. Lattice Boltzmann simulations of margin perpendicular fluid flow through the pore network in this zone rendered by xray computed micro tomography of this zone shows a reduction in permeability by 2 orders of magnitude from ~10-11.5 to ~10-13 m2. Textural changes of conduit walls that experienced mafic Plinian eruptions have rarely been reported and imply an unusual coupling between a gas-magma-suspension explosively bypassing a heated margin. It is possible that transient coupling events were enough to induce ductile simple shear in the margin rock. Such shear strain and resultant pore closure at elevated temperatures could be a mechanism by which permeability of conduit walls is reduced. Low permeability implies an inefficient pore-pressure release valve and thus overpressures could be maintained, exerting unusually high stresses within the basaltic melt. If these stresses could not be viscously dissipated over the timescale of degassing, then conduit wall sealing contributes to the explosivity of such large eruptions.

Schauroth, J.; Wadsworth, F.; Vasseur, J.; kennedy, B.; Schipper, C.; Kueppers, U.; Scheu, B.; Dingwell, D. B.

2013-12-01

275

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

Directory of Open Access Journals (Sweden)

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.

Hirahara Noriyuki

2012-01-01

276

A numerical code of explosive conduit flows constrained by large-scale experiments  

Science.gov (United States)

Conduit exit conditions during explosive eruptions play a major role in determining the rate and style of the eruptive column. The main parameter characterizing the eruptive mixture at conduit exit is mass eruption rate (MER), which is the product of velocity, density and conduit section area. This was perceived by the first researchers, who constructed theoretical model on the dynamics of explosive eruptions (Wilson et al., 1980; Woods, 1988; Bursik and Woods, 1991). Numerical modelling also helped scientists in the understanding of the complex dynamics of this kind of eruptions (Macedonio et al., 2005; Neri et al., 1998; Papale, 2001; Papale et al., 1998). Finally, the first large scale experiments on the mechanics of eruptive columns and pyroclastic flows (Dellino et al., 2007) allowed the development of an empirical model for the prediction of exit velocity of eruptive mixtures and the conditions of existence of the main eruptive styles (Dellino et al., 2009). Since the experiments were successfully scaled to real eruptions, we implemented a numerical model that reproduces the main quantities measured in the experiments, with the aim of eventually extending the model to the natural case. This would be the first time that a numerical model on the mechanics of explosive eruptions is validated against large-scale experiments. A steady 1-D two phase numerical model of the conduit flow is presented here. In this model the equations of conservation of mass and momentum for gas and volcanic particles are solved via a Runge-Kutta method with an adaptive stepsize. The numerical model is implemented in a code written in Fortran 77 language. The use of an adaptive stepsize control over the Runge-Kutta method allows the achievement of a predetermined accuracy (in this case of the order of 10-5) with minimum computational effort. All the conditions of the experimental runs are implemented and the velocity field is initialized using the empirical model for mixture velocity (Dellino et al., 2009). The model takes in account the real shape of volcanic ash and uses the well established law of Dellino et al. (2005) for the calculation of particles' terminal velocity. The pressure gradient in the conduit, which represents the main driving force of the vertical two-phase flow, is obtained by the same empirical model (Dellino et al., 2009). Finally the interphase drag force and the friction between the phases and the conduit wall are included: the classic empirical laws for wall-particles and wall-fluid frictions developed in industrial engineering and classic fluid dynamics are implemented in the code. All the experimental runs have been simulated with the numerical code, and the model results in velocities that are quite consistent with experiments.

Dioguardi, Fabio; de Lorenzo, Salvatore; Dellino, Pierfrancesco

2010-05-01

277

The Short Saphenous Vein: A Viable Alternative Conduit for Coronary Artery Bypass Grafts Harvested Using a Novel Technical Approach  

Science.gov (United States)

A multitude of vascular conduits are available to the Cardiac Surgeon performing Coronary Artery Bypass Graft operations. The Internal Mammary Artery, Radial Artery (RA), and the Long Saphenous Vein (LSV) have proven to be excellent conduits, especially in the current era of statin usage. However, previous stripping or varicosities of the LSV and calcification of the RA, coupled with the need for multiple vessel grafting, requires an alternative candidate. We describe a novel harvesting technique for bilateral simultaneous Short Saphenous Vein harvest and propose this, often forgotten vein, as a viable alternative conduit.

Sarwar, Umran; Chetty, Govind; Sarkar, Pradip

2012-01-01

278

Glycol still column vapor emissions  

International Nuclear Information System (INIS)

Air quality control regulations are becoming more and more restrictive. This affects most of the equipment used in the gas processing industry. Both vapor and liquid emissions from glycol dehydration units can be handled by Vapor Recovery Units (VRU). Vapors are burned in the reboiler. Liquids are condensed and pumped to storage. Details of these units are discussed in this paper

1992-03-16

279

The Vaporization of Pyrolytic Graphite.  

Science.gov (United States)

The vaporization of pyrolytic graphite was studied by the Knudsen effusion and Langmuir free vaporization techniques using a microbalance and a time-of-flight mass spectrometer. Vapor pressures were obtained in the temperature range 2417K - 2700K for C, C...

P. D. Zavitsanos

1966-01-01

280

Vaporized liquid fuel combustion apparatus  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a vaporized liquid fuel combustion apparatus comprising: a cylinder defining a combustion chamber, the cylinder having an inlet end for receipt of combustion air, a first flange surrounding the inlet end and an outlet end for exhausting gaseous combustion products; means for introducing the fuel into the combustion chamber and ignition means exposed to the combustion chamber through the cylinder; an end plate at least partially covering the inlet end of the cylinder and defining an opening for the admission of combustion air into the combustion chamber, the end plate having a second flange surrounding its periphery, the second flange mating with the first flange; a cylindrical heat exchanger for indirect heat exchange between the combustion products and a fluid to be heated, the heat exchanger surrounding the outlet end of the cylinder and having a third flange at one end thereof, the third flange mating with the first and second flanges; a blower for feeding air to the combustion chamber, the blower having an end portion contoured to mate with the first, second and third flanges; and means for detachably securing the first, second and third flanges and the blower end portion together to form a single gaslight flanged joint, the cylinder, blower end plate and heat exchanger being separable components secured together only at the single flanged joint.

Kimijima, Y.; Kikuchi, K.

1986-11-18

 
 
 
 
281

Extracardiac Fontan with T-shape conduit in non-confluent pulmonary arteries  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract A 34 months-old male patient with double inlet right ventricle with nonconfluent pulmonary arteries who underwent successful extracardiac fenestarated Fontan procedure using pre-designed T-shaped PTFE vascular graft after multi-step rehabilitation of the diminutive hilar pulmonary arteries. At first we performed 6 mm confluent pulmonary artery vascular graft implantation with 4 mm BT shunt at patient's 4 weeks old. At 9 months of patient, we upsized the confluent pulmonary arterial graft to 8 mm with bidirectional cavopulmonary connection, and, at 34 months, we performed extracardiac conduit Fontan procedure with pre-designed T-shape conduit including the confluent pulmonary arterial portion at last. Patient shows excellent functional status and development.

Bae Eun

2008-02-01

282

TPX superconducting cable-in-conduit 1995 design and development progress  

Energy Technology Data Exchange (ETDEWEB)

A unique feature of the magnet system for the Tokamak Physics Experiment (TPX) is that all the magnets are superconducting. With the exception of the outer poloidal coils, the magnet system uses Nb{sub 3}Sn cable-in-conduit conductor; the outer poloidal coils use Nb-Ti cable-in-conduit conductor. We describe the current TPX conductor design and present a progress report on the conductor development. Our strand development contracts have resulted in demonstrating that at least two vendors can produce Nb{sub 3}Sn strand which meets the TPX specification. Subcable testing gives confidence that the TPX conductor will satisfy the magnet operational requirements. Fabrication of full-size conductors is underway and tests on these will give verification that the TPX conductor meets the operational requirements. Our industrial cabling and sheathing contract to produce demonstration conductor using copper strands is exploring a production technique that differs from the conventional tube mill approach.

Zbasnik, J.P.; Martovetsky, N.N.; Hibbs, S.M. [and others

1995-09-29

283

TPX superconducting cable-in-conduit 1995 design and development progress  

International Nuclear Information System (INIS)

A unique feature of the magnet system for the Tokamak Physics Experiment (TPX) is that all the magnets are superconducting. With the exception of the outer poloidal coils, the magnet system uses Nb3Sn cable-in-conduit conductor; the outer poloidal coils use Nb-Ti cable-in-conduit conductor. We describe the current TPX conductor design and present a progress report on the conductor development. Our strand development contracts have resulted in demonstrating that at least two vendors can produce Nb3Sn strand which meets the TPX specification. Subcable testing gives confidence that the TPX conductor will satisfy the magnet operational requirements. Fabrication of full-size conductors is underway and tests on these will give verification that the TPX conductor meets the operational requirements. Our industrial cabling and sheathing contract to produce demonstration conductor using copper strands is exploring a production technique that differs from the conventional tube mill approach

1995-10-04

284

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

Science.gov (United States)

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

Hausner, Thomas; Marvaldi, Letizia; Marton, Gabor; Pajer, Krisztian; Hopf, Rudolf; Schmidhammer, Robert; Hausott, Barbara; Redl, Heinz; Nogradi, Antal; Klimaschewski, Lars

2014-01-01

285

Vibration analysis on the hot gas conduit in 10 MW HTR  

International Nuclear Information System (INIS)

Based on structural characteristics of the hot gas conduit for the high temperature gas cooled reactor (HTR), of which inside and outside is blown by the reverse direction two flows at same time, the authors established the theoretical model for design condition to study flow induced vibration, that is a single span cylinder contained flowing gas and surrounded by reverse direction flow, simply supported at each end. The mathematical equations and the simple method to solve it is given. The frequency as a function of flow velocity, the critical velocity at which cylinder lost stability in various flow conditions, and the stability map are obtained. The analysis results are that the design condition of hot gas conduit falls in the stability area, in other word, running at design condition, the flow induced large amplitude vibration does not exist

1997-05-01

286

Heat transfer characteristics of cable-in-conduit type forced flow cooled superconductor  

International Nuclear Information System (INIS)

Heat transfer characteristics of a cable-in-conduit conductor are measured for the Reynolds numbers of 1000-6000. Heat transfer coefficients were estimated by the transient temperatures at the inlet and outlet of the conduit, and these measured values were used as boundary conditions in a heat transfer simulation. In this way, the heat transition simulations were used to estimate the heat transfer coefficients. The Reynolds numbers of our experiments spanned the laminar and turbulent flow regimes. Our estimated heat transfer coefficients indicate, however, that heat transfer over this flow range is similar to heat transfer in te turbulent flow regime, as expressed by the Dittus-Boelter correlation. Our estimated heat transfer coefficients were about 25% higher than those determined using the Dittus-Boelter correlation. (author)

1994-09-01

287

Optimization of Nb_3Sn cable-in-conduit superconductor for application to pulsed tokamak coils  

International Nuclear Information System (INIS)

Cable-in-conduit conductors in pulsed tokamak applications have design requirements imposed by the tokamak operation: typically an operating temperature dependent on the AC losses and pulse time, the field by the tokamak performance and a quench discharge time by the coil voltage limits. The void fraction of helium in the cable is determined by mechanical and thermal stability considerations. It is then possible to maximize the cable space current density for a given temperature margin and strand properties, using the procedure in the companion paper ''Parametric Study of Cost Functions in Cable-in-Conduit-Conductors''. Nb_3Sn strands can typically offer high Jc, high loss or low loss, low Jc. The sensitivity of the cable design to the choice of strand is discussed with reference to the quantity of strand and the achievable current density

1994-07-01

288

Development of ITER TF Cable-in-Conduit Conductors and Their Characteristics  

International Nuclear Information System (INIS)

As a participant taking part in the ITER TF conductor R and D program, we developed two toroidal field conductors with variations of conduit thickness resulting in the different void fraction of the conductors. The estimated void fractions of the conductors are 31% and 33%. In this paper we present the details of the TF conductor development and performance test results of them carried out by the measurement of current sharing temperature under cyclic loading. Regarding the conductor development, the internal-Sn-processed Nb3Sn strand characteristics, strand cabling, twist pitch and characteristics of the conduit materials are presented. For the understanding of the conductor design and performance, the conductor test results are presented and the effect of the conductor design parameters such as void fraction and twist pitch is discussed based on the results.

2009-04-01

289

Copper vapor laser modular packaging assembly  

Energy Technology Data Exchange (ETDEWEB)

A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment.

Alger, Terry W. (Tracy, CA); Ault, Earl R. (Dublin, CA); Moses, Edward I. (Castro Valley, CA)

1992-01-01

290

Vapor-liquid phase separator studies  

International Nuclear Information System (INIS)

Porous plugs serve as both entropy rejection devices and phase separation components separating the vapor phase on the downstream side from liquid Helium 2 upstream. The liquid upstream is the cryo-reservoir fluid needed for equipment cooling by means of Helium 2, i.e Helium-4 below its lambda temperature in near-saturated states. The topics outlined are characteristic lengths, transport equations and plug results

1983-01-01

291

Controlled vapor-liquid-solid growth of indium, gallium, and tinoxide nanowires via chemical vapor transport  

Energy Technology Data Exchange (ETDEWEB)

We utilized a vapor-liquid-solid growth technique tosynthesize indium oxide, gallium oxide, and tin oxide nanowires usingchemical vapor transport with gold nanoparticles as the catalyst. Usingidentical growth parameters, we were able to synthesize single crystalnanowires typically 40-100 nm diameter and more than 10-100 m long. Theproducts were characterized by means of X-ray diffraction (XRD), scanningelectron microscopy (SEM), and high-resolution transmission electronmicroscopy (HRTEM). All the wires were grown under the same growthconditions with growth rates inversely proportional to the source metalvapor pressure. Initial experiments show that different transparent oxidenanowires can be grown simultaneously on a single substrate withpotential application for multicomponent gas sensors.

Johnson, M.C.; Aloni, S.; McCready, D.E.; Bourret-Courchesne, E.D.

2006-03-31

292

Results of a Seven-Year, Single-Centre Experience of the Long-Term Outcomes of Bovine Ureter Grafts Used as Novel Conduits for Haemodialysis Fistulas  

International Nuclear Information System (INIS)

Purpose: To report the long-term outcomes of bovine ureter grafts as novel conduits for haemodialysis fistulas. Materials and Methods: Thirty-five patients underwent placement of a total of 40 SynerGraft 100 (SG100; CryoLife Europa®, Guildford, UK) bovine ureter grafts between April 2002 and February 2009. Prospective data were collected on all patients, including active surveillance with blood flow studies and 6-monthly duplex ultrasound studies. Main outcome measures were primary and secondary patency rates. Results: Mean follow-up time was 97 weeks (range 4–270). Thirteen patients died from unrelated causes during the study period; 12 of these patients had a functioning graft at the time of death. Five patients underwent transplantation, and all had a functioning graft at transplantation. Twelve patients had a functioning graft at the end of the study period. One hundred and ten stenoses were detected, and 97 venoplasty procedures were performed. Of the stenoses, 41.8% were located at the venous anastomosis, 12.7% within the graft, 17.3% in the outflow veins, and 28.1% in central veins. No arterial stenoses were detected. Primary patency rates were 53% at 6 months and 14% at 1 year. Secondary patency rates were 81% at 6 months, 75% at 1 year, and 56% at 2 years. Conclusions: Active surveillance and intervention was able to achieve satisfactory long-term secondary patency for these novel conduits compared with those made of PTFE seen in other studies.

2011-10-01

293

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 e...

Hirahara Noriyuki; Yamamoto Tetsu; Tanaka Tsuneo

2012-01-01

294

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

1983-01-01

295

A 10-cm big stone formed in ileal conduit six years after cystectomy  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION: Ileal conduit (IC is the standard urinary diversion following radical cystectomy. The formation of stone in the IC is one of the relatively common late complications of the procedure. CASE REPORT: The case of 69-year-old man who developed 10-cm large stone in the IC, six years after cystectomy is presented. CONCLUSION: The majority of patients with the stone in IC can be treated with minimally invasive techniques, like manual extraction, or endoscopic procedures.

Topuzovi? ?edomir

2012-01-01

296

Biosorption of Copper by a Bacterial Biofilm on a Flexible Polyvinyl Chloride Conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Inexpensive technologies with less-than-optimal efficiencies as a strategy for countering economic restraints to pollution control have been evaluated by using a laboratory-scale biotreatment process for copper-containing effluent. Economizing measures include the use of polyvinyl chloride (PVC) cylinders fashioned from commercially available flexible PVC conduit to support a biofilm that was cultured in an inexpensive medium prepared in wastewater. The biofilm was challenged by aqueous coppe...

Qureshi, Fouad M.; Badar, Uzma; Ahmed, Nuzhat

2001-01-01

297

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 deter...

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

2011-01-01

298

Large bifid ureteric calculus in a patient with an ileal conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Rajaian, Shanmugasundaram; Kekre, Nitin S.

2012-01-01

299

Simulation of 3D karst conduits with an object-distance based method integrating geological knowledge  

Science.gov (United States)

Karst conduit shapes have a high influence on fluid flows. As these underground hidden systems are partially inaccessible, their stochastic simulation is an essential tool to assess the uncertainties related to these highly exploited water resources. The object-distance simulation method (ODSIM) is a hybrid dual-scale approach that has been recently proposed to model geological underground structures due to late processes such as dolomitized rocks, mineralized veins or karsts. Using a perturbed Euclidean distance field around a curve representing roughly the conduit centre and called a skeleton, the resulting shapes are globally cylindrical-like 3D envelopes. But at a drain scale, karstic conduits are elongated along weakness planes such as lithostratigraphic horizons, bedding planes, fractures or faults. In addition to those planes the influence of the water table is added. This work presents different improvements of ODSIM methodology for simulating more realistic shapes in the particular case of karst. Firstly, we propose using a custom distance field computed with a fast marching method. Considering the “velocity” field to be proportional to the permeability allows the resulting features to be elongated along the weakness planes. Secondly, to handle specific shapes due to the proximity of the water table, such as trenches or notches, we impose areas of higher velocity between the skeleton and the water table. Finally, we generate a custom random threshold with several variograms and/or distributions depending on the different features integrated in the “velocity” field. Applied on different models, it is shown that the resulting karst conduits have more realistic shapes than those obtained with the previous workflow, while the variability of structures which can be modelled with ODSIM is preserved.

Rongier, Guillaume; Collon-Drouaillet, Pauline; Filipponi, Marco

2014-07-01

300

Pipe-laying machine for oil pipelines, conduits and the like  

Energy Technology Data Exchange (ETDEWEB)

A device for laying pipelines, conduits, etc. includes a pair of self-propelled vehicles joined by an intermediate bridge having a rigid lifting arm hinged at one end to the intermediate bridge and has a device for gripping and lifting the pipes carried by the free end of the rigid arm such that the rigid lifting arm may be controlled to engage a pipe and lift it over the trench and lower the pipe into the desired position.

Cecchi, C.; Bifani, A.G.

1979-09-04

 
 
 
 
301

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

1995-03-01

302

Development and fabrication of superconducting hybrid Cable-In-Conduit-Conductor (CICC) for indigenous fusion programme  

International Nuclear Information System (INIS)

The Atomic Fuels Division has initiated development and fabrication of Cable-In-Conduit-Conductor (CICC) of various configurations, for superconducting fusion grade magnets required for their indigenous Fusion Programme. The process involves development of high grade superconducting multifilamentary wire, multi stage cabling of superconducting as well as copper wires and, finally, jacketing of the cables in SS316LN tubes. The overview of the development and fabrication of CICC is presented in this article. (author)

2011-01-01

303

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

International Nuclear Information System (INIS)

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

2007-10-01

304

CO2 outgassing in a combined fracture and conduit karst aquifer near lititz spring, Pennsylvania  

Science.gov (United States)

Lititz Spring in southeastern Pennsylvania and a nearby domestic well were sampled for 9 months. Although both locations are connected to conduits (as evidenced by a tracer test), most of the year they were saturated with respect to calcite, which is more typical of matrix flow. Geochemical modeling (PHREEQC) was used to explain this apparent paradox and to infer changes in matrix and conduit contribution to flow. The saturation index varied from 0.5 to 0 most of the year, with a few samples in springtime dropping below saturation. The log PCO2 value varied from -2.5 to -1.7. Lower log PCO2 values (closer to the atmospheric value of -3.5) were observed when the solutions were at or above saturation with respect to calcite. In contrast, samples collected in the springtime had high PCO2, low saturation indices, and high water levels. Geochemical modeling showed that when outgassing occurs from a water with initially high PCO2, the saturation index of calcite increases. In the Lititz Spring area, the recharge water travels through the soil zone, where it picks up CO2 from soil gas, and excess CO 2 subsequently is outgassed when this recharge water reaches the conduit. At times of high water level (pipe full), recharge with excess CO 2 enters the system but the outgassing does not occur. Instead the recharge causes dilution, reducing the calcite saturation index. Understanding the temporal and spatial variation in matrix and conduit flow in karst aquifers benefited here by geochemical modeling and calculation of PCO2 values. ?? 2006 Geological Society of America.

Toran, L.; Roman, E.

2006-01-01

305

Empirical investigation of factors affecting the stability of cable-in-conduit superconductors  

International Nuclear Information System (INIS)

Experiments investigating the stability of cable-in-conduit superconductors were performed using test conductors composed of small, quadruplex cables enclosed in steel tubes. To examine the effects of a variation in stabilizer resistivity, all test conductors contained two strands of identical NbTi/Cu composite superconductor and two strands of solid copper. The observations are compared with other data in the literature. (author)

1985-01-01

306

Surgeon at Work: Hand-Assisted Laparoscopic Construction of Gastric Conduit for Thoracic Esophageal Cancer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method for hand-assisted laparoscopic construction of gastric conduit for thoracic esophageal cancer was developed. Since this endoscopic surgical procedure is less invasive than open surgery, it contributes to improvement of post-operative respiratory functions and reduces respiratory complications. What distinguishes our surgical procedure is that unlike methods described in previous reports, it begins with treatment of the left gastroepiploic vessels at the height of the i...

Aoki, Tatsuya; Tsuchida, Akihiko; Osaka, Yoshiaki; Takagi, Yu; Shinohara, Motoo; Okada, Ryosuke; Tomioka, Hidenori; Koyanagi, Yasuhisa

2001-01-01

307

A 10-cm big stone formed in ileal conduit six years after cystectomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

INTRODUCTION: Ileal conduit (IC) is the standard urinary diversion following radical cystectomy. The formation of stone in the IC is one of the relatively common late complications of the procedure. CASE REPORT: The case of 69-year-old man who developed 10-cm large stone in the IC, six years after cystectomy is presented. CONCLUSION: The majority of patients with the stone in IC can be treated with minimally invasive techniques, like manual extraction, or endoscopic procedures.

Topuzovi? ?edomir; Pej?i? Tomislav; ?uraši? Ljubomir; Hadži-?oki? Jovan

2012-01-01

308

Calibration of inductive heating energy deposited on a cable-in-conduit conductor using a calorimetric method  

International Nuclear Information System (INIS)

The inductive heating method is often used to originate initial normalcy in a stability experiment of a cable-in-conduit conductor (CICC). However, its magnitude cannot be evaluated easily. The calibration method to determine the CICC's inductive heating energy using a calorimetric technique was studied, and the inductive heating energies of two CICCs whose geometries were different from one another were successively evaluated applying this method. In addition, the experimental results show that the eddy currents in the strands and conduit electrically couple separately from one another and that this phenomenon affects the heating energy in the strands and conduit. The inductive heating energy in the strands and conduit was evaluated taking into account this effect. (J.P.N.)

1997-06-01

309

Stratified vapor generator  

Energy Technology Data Exchange (ETDEWEB)

A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).

Bharathan, Desikan (Lakewood, CO); Hassani, Vahab (Golden, CO)

2008-05-20

310

Predicting travel times and transport characterization in karst conduits by analyzing tracer-breakthrough curves  

Science.gov (United States)

SummaryThis paper analyzes data obtained in 26 tracer tests carried out in 11 karstic connections following solutional conduits in karst aquifers in the Basque Country. These conduits are preferential drainage pathways in these aquifers and so they confer a marked anisotropy and high vulnerability to them. Consequently, their consideration in protection and management studies and projects is a priority. The connections studied cover a wide hydrogeological spectrum (a wide range of sizes, slopes, geomorphic and hydrologic types) and the tests have been carried out at different hydrodynamic states. It is noteworthy that they all follow a similar trend, which has allowed for the development of a statistical approximation for the treatment of the whole information. Relationships have been established involving velocity, solute time of arrival, attenuation of peak concentration and time of passage of tracer cloud. These relationships are a valuable tool for management and supporting decision-making and allow for making estimates in connections in which the information available was scarce. This information is especially useful, given that the complexity of transport in karst conduits gives way to important deviations between real data (empirical observations) and the data obtained by simple approaches based on the Fickian-type diffusion equation.

Morales, Tomás; Fdez. de Valderrama, Iñigo; Uriarte, Jesús A.; Antigüedad, Iñaki; Olazar, Martin

2007-02-01

311

Laparoscopic radical cystectomy: neobladder or ileal conduit, debate still goes on  

Science.gov (United States)

Objective To compare the pre, intra, and post–operative data between ileal conduit and neobladder urinary diversions during laparoscopic radical cystectomy(LRC). Material and methods Between 2006 and 2011, 63 patients who underwent LRC and urinary diversion had their data input prospectively into a database and said data used for the analysis. The outcome comparators were the patient demographics, operative time, conversion rate, blood loss, transfusion rate, morphine analgesic requirement, length of hospital stay, complication rates, follow up, and quality of life assessments. A Mantel–Haenszel test was used for dichotomous data and an inverse variance method was used for continuous data. P values less than 0.5 were considered significant Results Thirty–nine patients (60 ±7.11 years) had ileal conduits and 24 patients (57 ±8.68 years) had neobladder urinary diversion. No difference was found (P >0.05) regarding age, BMI, smoking history, TURBT pathology result, blood loss, blood transfusion requirement, conversion rates, length of hospital stay, morphine requirement, complications, or follow–up and quality of life. The neobladder groups did have more previous abdominal operations and had significantly longer operative time. Conclusions We found no difference between either types of diversion in all comparative aspects except that the neobladder had longer operative times. This is the first comparative study between ileal conduit and neobladder urinary diversion after laparoscopic radical cystectomy and can pose as a bench mark for future comparisons.

Drewa, Tomasz; Olejniczak, Pawel; Chlosta, Piotr L.

2014-01-01

312

Development of a 30-kA cable-in-conduit conductor for pulsed poloidal coils  

International Nuclear Information System (INIS)

This paper describes design parameters of a 30-kA cable-in-conduit conductor (JF-30), and the test results of stability margin measured by using a triplex in a conduit. Cross sectional size of JF-30 is 35mm X 35 mm and 567 NbTi-Cu-CuNi strands are in a stainless steel conduit whose thickness is 2 mm. Void fraction is 33 % and the designed stability margin is 270 mJ/cc at 5 atm and 7 T. Stability test by a triplex showed a favorable margin, a few hundreds of mJ at 7 T even without helium flow. In addition, the stability was strongly increased when helium flow up to 0.2 g/s was applied. At around 3 atm, the authors found that the stability margin was more than 2 J/cc which exceeded the present heater capacity. This resulted in an extension of current range, in which the sample is stable, up to 150 to 200 % when compared to the case without helium flow

1983-01-01

313

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

Science.gov (United States)

Urinary diversion after extirpative surgery of the bladder is done by various methods. Conduit urinary diversion is the most commonly practiced method of urinary diversion. It is relatively easy to perform and has a lower complication rate than other forms of diversion, e.g., orthotopic neobladder and continent cutaneous urinary diversion. Urolithiasis is a known and common complication of urinary diversion. Upper tract calculi in these cases often manifest symptomatically as occurs in the general population. Stones in the conduit can have a variable clinical presentation. Asymptomatic presentation is also noted in a few cases. We report a case of a large silent bifid ureteric calculus within an ileal conduit in a woman who had undergone urinary diversion 32 years earlier. Plain X-ray of the abdomen is the only investigation necessary to rule out urinary lithiasis in those who have had urinary diversion for a long time. This simple tool can diagnose the condition well in advance and aid in planning the management of this condition. PMID:23248527

Rajaian, Shanmugasundaram; Kekre, Nitin S

2012-09-01

314

Effects of streptozotocin-induced diabetes on the pharmacology of rat conduit and resistance intrapulmonary arteries  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Poor control of blood glucose in diabetes is known to promote vascular dysfunction and hypertension. Diabetes was recently shown to be linked to an increased prevalence of pulmonary hypertension. The aim of this study was to determine how the pharmacological reactivity of intrapulmonary arteries is altered in a rat model of diabetes. Methods Diabetes was induced in rats by the ?-cell toxin, streptozotocin (STZ, 60 mg/kg, and isolated conduit and resistance intrapulmonary arteries studied 3–4 months later. Isometric tension responses to the vasoconstrictors phenylephrine, serotonin and PGF2?, and the vasodilators carbachol and glyceryl trinitrate, were compared in STZ-treated rats and age-matched controls. Results STZ-induced diabetes significantly blunted the maximum response of conduit, but not resistance pulmonary arteries to phenylephrine and serotonin, without a change in pEC50. Agonist responses were differentially reduced, with serotonin (46% smaller affected more than phenylephrine (32% smaller and responses to PGF2? unaltered. Vasoconstriction caused by K+-induced depolarisation remained normal in diabetic rats. Endothelium-dependent dilation to carbachol and endothelium-independent dilation to glyceryl trinitrate were also unaffected. Conclusion The small resistance pulmonary arteries are relatively resistant to STZ-induced diabetes. The impaired constrictor responsiveness of conduit vessels was agonist dependent, suggesting possible loss of receptor expression or function. The observed effects cannot account for pulmonary hypertension in diabetes, rather the impaired reactivity to vasoconstrictors would counteract the development of pulmonary hypertensive disease.

Howarth Frank C

2009-01-01

315

Flambage vertical des conduites en souillées Vertical Buckling of Buried Pipes  

Directory of Open Access Journals (Sweden)

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.

Bournazel C.

2006-11-01

316

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

Directory of Open Access Journals (Sweden)

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.

PEREIRA L.

1999-01-01

317

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 fric [...] tional 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.

PEREIRA, L.; MARRA JR, W.D.; COURY, J.R..

318

Analytical studies on hotspot temperature of cable-in-conduit conductors  

International Nuclear Information System (INIS)

This paper describes an analytical study to review the hotspot temperature design criteria of the cable-in-conduit conductors for the ITER magnet system. The ITER magnet system uses three kinds of cable-in-conduit conductors for the Toroidal Field (TF) coils, the Central Solenoid (CS) and the Poloidal Field (PF) coils. The amount of copper in the superconducting cable has been defined by using the classical hotspot temperature design criteria that is based on the adiabatic condition. In the current design, ITER superconducting cables include a large amount of pure copper strands to satisfy the classical criteria. However, temperature and stress in the conduit and insulations after quench can be simulated with the quench simulation program and stress analysis program using the latest analysis tools. This analysis shows that the strand temperature is dominated by the conduction along strands and the heat capacity of other conductor materials and coolant. The hotspot temperature depends strongly on the delay time for quench detection. This analysis provides an estimation of delay times for quench detection. The thermal and stress analysis can provide the maximum allowable temperature after quench by determination of a failure or a functional disorder condition of the jacket material and turn insulation. In conclusion, it is found that the current density of the cable space can be increased, by reducing the extra copper strand, thereby, allowing a reduction of the coil radial build. (author)

2001-11-01

319

Skeletonization of radial and gastroepiploic conduits in coronary artery bypass surgery  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The use of a skeletonized internal thoracic artery in coronary artery bypass graft surgery has been shown to confer certain advantages over a traditional pedicled technique, particularly in certain patient groups. Recent reports indicate that radial and gastroepiploic arteries can also be harvested using a skeletonized technique. The aim of this study is to systematically review the available evidence regarding the use of skeletonized radial and gastroepiploic arteries within coronary artery bypass surgery, focusing specifically on it's effect on conduit length and flow, levels of endothelial damage, graft patency and clinical outcome. Four electronic databases were systematically searched for studies reporting the utilisation of the skeletonization technique within coronary revascularisation surgery in humans. Reference lists of all identified studies were checked for any missing publications. There appears to be some evidence that skeletonization may improve angiographic patency, when compared with pedicled vessels in the short to mid-term. We have found no suggestion of increased complication rates or increased operating time. Skeletonization may increase the length of the conduit, and the number of sequential graft sites, but no clear clinical benefits are apparent. Our study suggests that there is not enough high quality or consistent evidence to currently advocate the application of this technique to radial or gastroepiploic conduits ahead of a traditional pedicled technique.

Darzi Ara

2007-06-01

320

Chemical vapor composites (CVC)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Reagan, P.

1993-01-01

 
 
 
 
321

The vapor pressures of explosives  

Energy Technology Data Exchange (ETDEWEB)

The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

2013-01-05

322

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

Directory of Open Access Journals (Sweden)

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.

Jiang Xinquan

2011-07-01

323

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 tech...

Yu Wenwen; Zhao Wen; Zhu Chao; Zhang Xiuli; Ye Dongxia; Zhang Wenjie; Zhou Yong; Jiang Xinquan; Zhang Zhiyuan

2011-01-01

324

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

Science.gov (United States)

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.

2011-01-01

325

Characterization of a cavern conduit system in Vietnam by time series correlation, cross-spectrum and wavelet analyses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Time series analyses are applied to characterize the transient flow regimes of the Nam La cavern conduit, northwest Vietnam. The conduit transforms the input signal to an output signal, and the degree of transformation provides information on the nature of the flow system. The input for the analysis is net precipitation and the flow hydrograph at the cave entrance, while the output series is the flow hydrograph at the resurgence. Cross-correlation and cross-spectrum analysis are used to inves...

Tam, V. T.; Smedt, F.; Batelaan, Okke; Dassargues, Alain

2004-01-01

326

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS  

Energy Technology Data Exchange (ETDEWEB)

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.

Eric M. Suuberg; Vahur Oja

1997-07-01

327

Hydrocarbon vapor diffusion in intact core sleeves  

International Nuclear Information System (INIS)

The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the US Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact core sleeve sample was swept with nitrogen gas to simulate the diffusive release of hydrocarbon vapors from residual aviation gasoline in and immediately above the capillary fringe to a soil-venting air flow in the unsaturated zone. The resulting steady-state profile was modeled using existing diffusivity and air porosity estimates in a balance of diffusive flux and a first order source term. The source strength, which was calibrated with the observed flux of 2,2,4-TMP leaving the sleeve, varied with the residual gasoline remaining in the core, but was independent of the headspace sweep flow rate. This finding suggested that lower soil-venting air flow rates were in principle as effective as higher air flow rates in venting LNAPL vapors from contaminated soils. The saturated vapor concentration ratio of 2,2,4-TMP to 2,2,5-TMH decreased from 6.6 to 3.5 over the duration of the experiments in an expression of distillation effects. The vertical profile model was tested against sample port data in four separate experiments for both species, yielding mean errors ranging from 0 to -24% in magnitude

1993-01-01

328

Fe behavior in iron-bearing phonolitic and pantelleritic melts and its significance for magma dynamics in the volcanic conduits  

Science.gov (United States)

The style of volcanic eruptions is determined entirely by dynamics of magma ascent in conduits. Physical properties of a silicate melt, particulary viscosity, are responsible for fragmentation processes, bubble growth and their ascent, which are in their turn related to explosivity of eruptions. Therefore, comprehension of the macroscopic properties of silicate melts is required for adequate conduit modelling. Considering eruptions of Mt. Vesuvius, Italy, we observe that eruption style varies from strombolian to plinean and sub-plinean which is related to the changes of melts viscosity in conduits. At Vesuvius the composition of volcanic deposits (III phase) is mainly phonolitic with 5 - 8 wt. % FeO. Fe changes the valence and coordination depending on oxidation state. The changing of iron coordination causes increasing or decreasing viscosity because of the presence of higher or lower amounts of Fe species coordinated with stronger covalence bonds. Mossbauer spectra of iron-bearing natural pantelleritic and phonolitic glasses were studied to get data on speciation and coordination state of iron. Mössbauer spectroscopy measures hyperfine interactions (isomer shift (IS)) and quadrupole splitting (QS)) at Fe atoms embedded in glass structure, which provide the amount of ferric and ferrous iron and their coordination state depending on Redox conditions. Based on these data, we have considered redox-viscosity relationships and also iron coordination effects on viscosity of both mentioned natural melt compositions. For glasses, due to short range order, the Mössbauer spectra were fitted using mathematical procedures based on functional analysis (extended Voight lineshape included in "Recoil" and "Mosslab" software). Mössbauer spectra are deconvoluted in two sites: ferrous iron (IS=0,79-1,00 mm/s; QS= 1,78-2,25 mm/s) and ferric iron (IS=0,26-0,50 mm/s; QS= 0,75-0,95 mm/s). For both sites we observe that IS and QS gradually decrease towards more oxidized conditions. From functional analysis of Mössbauer spectra this increasing is due to transformation of iron coordination: Fe2+ [5]-Fe2+ [4] and Fe3+ [5]-Fe3+ [4], depending on Redox conditions. XANES data helps us to prove coordination transformation of Fe clearly. This methods (Giuli et al., 2011) reveal that Fe3+ is always in tetrahedral coordination and Fe2+ is in the form of both [4] and [5] species. The presence of minor [5] or even [6] cannot be excluded. Combining Mössbauer and XANES methods, we can suggest that more reduced samples include more high coordinated Fe species. Under oxidized conditions Fe3+ tends to be [4] - coordinated completely and amount of Fe2+ [5] decreases. Viscosity for phonolitic and pantelleritic melts increases as well with more oxidized conditions, suggesting more polymerized structure. Under reduced conditions, low viscosity means that some higher coordinated Fe2+ and Fe3+ sites occur in structure and function as a depolymerizing factor. Therefore, in the presence of iron-bearing peralkaline melts, the prediction of an eruptive style requires knowledge of the dependence of viscosity on thermodynamic parameters as well as dependence on RedOx conditions, which are responsible for ferric and ferrous iron structural transformations.

Borovkov, Nikita; Hess, Kai-Uwe; Fehr, Karl-Thomas; Cimarelli, Corrado; Dingwell, Donald Bruce

2014-05-01

329

Fibrin conduit supplemented with human mesenchymal stem cells and immunosuppressive treatment enhances regeneration after peripheral nerve injury.  

Science.gov (United States)

To address the need for the development of bioengineered replacement of a nerve graft, a novel two component fibrin glue conduit was combined with human mesenchymal stem cells (MSC) and immunosupressive treatment with cyclosporine A. The effects of MSC on axonal regeneration in the conduit and reaction of activated macrophages were investigated using sciatic nerve injury model. A 10mm gap in the sciatic nerve of a rat was created and repaired either with fibrin glue conduit containing diluted fibrin matrix or fibrin glue conduit containing fibrin matrix with MSC at concentration of 80×10(6) cells/ml. Cells were labeled with PKH26 prior to transplantation. The animals received daily injections of cyclosporine A. After 3 weeks the distance of regeneration and area occupied by regenerating axons and ED1 positives macrophages was measured. MSC survived in the conduit and enhanced axonal regeneration only when transplantation was combined with cyclosporine A treatment. Moreover, addition of cyclosporine A to the conduits with transplanted MSC significantly reduced the ED1 macrophage reaction. PMID:22465323

McGrath, Aleksandra M; Brohlin, Maria; Kingham, Paul J; Novikov, Lev N; Wiberg, Mikael; Novikova, Liudmila N

2012-05-16

330

The One Year Outcome after KTP Laser Vaporization of the Prostate According to the Calculated Vaporized Volume  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study was to develop a new simple method for measuring the vaporized volume and to evaluate the outcome of high-power potassium-titanyl-phosphate (KTP) photoselective laser vaporization. A total of 65 patients, with a mean age of 67.7 yr (range 53 to 85), were included in the primary analysis. The vaporized volume was calculated as the pre-operative volume minus the immediate post-operative volume plus the volume of the defect. For all patients, the subjective and objective pa...

2009-01-01

331

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)

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.

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

2010-12-01

332

Electrode testing in simple vapor-vapor AMTEC cells  

Energy Technology Data Exchange (ETDEWEB)

Alkali Metal Thermal to Electric Conversion (AMTEC) is under consideration for a range of applications from solar and radioisotope spacecraft power systems to micro-cogeneration in residential furnaces. AMTEC cells designed for many applications require series connection of individual beta-alumina solid electrolyte (BASE) tubes. In order to prevent short circuit conditions due to liquid sodium bridging to the metallic cell structure, this generally demands cell operation in a vapor-anode mode. The authors report here the results of a series of AMTC experiments carried out in a simple vapor-vapor mini-electrode test cell (METC). The cell provides for a once-through sodium supply, in order to provide rapid turnaround and avoid the assembly complications of providing for Na recirculation. This test cell design also provides a simple method to allow for operating a given electrode and current collector combination in both vapor-vapor and liquid-vapor states in a single experimental run. This capability allows a direct comparison between the larger body of historical data on liquid-vapor cells and the vapor-vapor systems now required.

Hunt, T.K.; Borkowski, C.A.; Childs, K.F.; Sievers, R.K. [Advanced Modular Power Systems, Ann Arbor, MI (United States)

1997-12-31

333

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

Science.gov (United States)

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.

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

2013-12-01

334

Delineating saturated conduit patterns and dimensions in the upper Floridan aquifer through numerical groundwater flow modeling (Invited)  

Science.gov (United States)

In groundwater flow modeling, aquifer permeability is typically defined through model calibration. Since the pattern and size of conduits are part of a karstic permeability framework, those parameters should be constrainable through the same process given a sufficient density of measured conditions. H2H Associates has completed a dual-permeability steady-state model of groundwater flow through the western Santa Fe River Basin, Florida from which a 380.9 km network of saturated conduits was delineated through model calibration to heads and spring discharges. Two calibration datasets were compiled describing average high-water and average low-water conditions based on heads at 145 wells and discharge from 18 springs for the high-water scenario and heads at 188 wells and discharge from 9 springs for the low-water scenario. An initial conduit network was defined by assigning paths along mapped conduits and inferring paths along potentiometric troughs between springs and swallets that had been connected by groundwater tracing. These initial conduit assignments accounted for only 13.75 and 34.1 km of the final conduit network respectively. The model was setup using FEFLOW™ where conduits were described as discrete features embedded in a porous matrix. Flow in the conduits was described by the Manning-Strickler equation where variables for conduit area and roughness were used to adjust the volume and velocity of spring flows. Matrix flow was described by Darcy’s law where hydraulic conductivity variations were limited to three geologically defined internally homogeneous zones that ranged from ~2E-6 m/s to ~4E-3 m/s. Recharge for both the high-water and low-water periods was determined through a water budget analysis where variations were restricted to nine zones defined by land-use. All remaining variations in observed head were then assumed to be due to conduits. The model was iteratively calibrated to the high-water and low-water datasets wherein the location, size and roughness of the conduits were assigned as needed to accurately simulate observed heads and spring discharges while bounding simulated velocities by the tracer test results. Conduit diameters were adjusted to support high-water spring discharges but the locations were best determined by calibration to the low-water head field. The final model calibrated to within 5% of the total head change across the model region at 143 of the 145 wells in the high-water scenario and at 176 of the 188 wells in the low-water scenario. Simulated spring discharges fell within 13% of the observed range under high-water conditions and to within 100% of the observed range under low-water conditions. Simulated velocities ranged from as low as 10-4 m/day in the matrix to as high as 10+3 m/day in the largest conduits. The significance of these results that we emphasize here is two-fold. First, plausible karstic groundwater flow conditions can be reasonably simulated if adequate efforts are made to include springs, swallets, caves, and traced flow paths. And second, detailed saturated conduit networks can be delineated from careful evaluation of hydraulic head data particularly when dense datasets can be constructed by correlating values obtained from different wells under similar hydraulic periods.

Kincaid, T. R.; Meyer, B. A.

2009-12-01

335

Water vapor retrieval from OMI visible spectra  

Directory of Open Access Journals (Sweden)

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.

H. Wang

2014-01-01

336

Fluorescence and nonradiative processes of dioxin vapors.  

Science.gov (United States)

Fluorescence, fluorescence excitation, biacetyl-sensitized phosphorescence excitation and absorption spectra of five dioxins (dibenzofuran, 2-chlirodibenzofuran, 2,8-dichlorodibenzofuran, dibenzo-p-dioxin and 2-chlorodibenzo-p-dioxin) have been measured in the vapor phase. The intersystem crossing yields of dioxin vapors have been determined by means of a biacetyl sensitized phosphorescence method. It is shown that the nonradiative rates from the S1 state of dibenzo-p-dioxins increase significantly with increasing excitation energy, while those of dibenzofurans are almost unchanged. It is also shown that the main nonradiative process from S1 for dibenzofurans is both the intersystem crossing to T1 and internal conversion to S0 which includes possible photodecomposition, while that for dibenzo-p-dioxins is the internal conversion to S0, which also may include possible photochemical decomposition processes. PMID:24309177

Itoh, Takao; Hashimoto, Ryuso

2014-03-25

337

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

LENUS (Irish Health Repository)

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.

Healy, David G

2012-02-03

338

Water vapor in the atmosphere over the northern Tien Shan  

Science.gov (United States)

Refined data of systematic measurements of total water vapor in the atmosphere from May 1980 to April 2005 are presented. The data were obtained at the Issyk Kul atmospheric-monitoring station by the method of solar molecular-absorption spectroscopy. Over 25 years, the annual mean water-vapor content in the atmosphere increased by 4.5% at a mean rate of increase of 0.18% per year. However, the water-vapor content decreased in the last five years. The results of statistical processing of experimental data (general statistical characteristics, correlation coefficients, composite oscillations) are described. A refined model is proposed for forecasts of temporal variations in the monthly mean and annual mean water-vapor contents for the coming years. The model includes a linear trend and the sum of oscillations with periods close to the periods of a number of well-known geophysical phenomena. Regression equations are proposed to relate the water-vapor content in the atmospheric column to the surface temperature and absolute humidity.

Aref'ev, V. N.; Kashin, F. V.; Semenov, V. K.; Akimenko, R. M.; Kamenogradskii, N. E.; Sizov, N. I.; Sinyakov, V. P.; Upenek, L. B.; Ustinov, V. P.

2006-12-01

339

Method for connecting a conduit to a subsea structure, and a device for use in connecting a conduit end to a subsea structure. Fremgangsmaate ved kopling av en ledning til en undervannsstruktur, samt anordning til bruk ved kopling av en ledningsende til en undervannsstruktur  

Energy Technology Data Exchange (ETDEWEB)

The invention relates to a method for connecting a conduit to a subsea structure, which comprises laying the conduit on the sea floor, with a conduit end in the area close to the subsea strucure. The method is characterized in that the conduit end is gripped by a Remote Operational Vehicle (ROV) with a gripping manipulator, that ROV with the gripped conduit end is advanced to the subsea structure, that the conduit end is introduced like a piston in a suitable receiving member in the subsea structure, and that a negative pressure is provided in the receiving member so that conduit end is sucked into the receiving member. The invention also relates to a device for use in connecting a conduit end to a subsea structure. Conduit end is advanced from the side of subsea strucure into a receiving member of the subsea structure and is secured there. Receiving member and conduit end are mutually adapted so that conduit end can move like a piston in receiving member. The receiving member has a connecting sleeve which is accessible from outside for connection to a source of negative pressure. 7 figs.

Norbom, E.; Sletten, R.

1991-07-15

340

Upgrading the NIFS superconductor test facility for JT-60SA cable-in-conduit conductors  

International Nuclear Information System (INIS)

The superconductor test facility at the National Institute for Fusion Science (NIFS) was upgraded to test cable-in-conduit (CIC) conductors for the JT-60SA equilibrium field (EF) coil. Supercritical helium (SHe) lines were assembled with transfer tubes and a heat exchanger. The CIC conductor was covered with a thermal insulation vessel, filled with gas helium at atmospheric pressure. The temperature of the conductor was varied using a film heater attached to an inlet pipe. Critical current (Ic) and current sharing temperature (Tcs) measurements of the prototype CIC conductor were carried out successfully in the upgraded test facility. During the measurements, the conductor temperature was precisely controlled.

2009-06-01

 
 
 
 
341

Interconnected Magmatic Conduit Systems as Recorded by Melt Inclusions From Masaya and Apoyo Calderas, Nicaragua.  

Science.gov (United States)

Masaya and Apoyo volcanoes in Nicaragua are large calderas formed from catastrophic explosive eruptions. Melt inclusions from Apoyo and Masaya Calderas in central Nicaragua are compared to a large prehistoric ignimbrite within the Las Sierras Formation to determine pre-eruptive conditions. Melt inclusion compositions and lava compositions of Masaya, Apoyo and Las Sierras volcanoes are mainly bi-modal. Masaya melt inclusions are basaltic with low water (typically Masaya melt inclusions and Masaya-like volatile concentrations at Apoyo are also observed. Moreover, Masaya-like whole rock compositions occur at Apoyo. We suggest that some melt exchange occurs between these two volcanoes through overlapping, interconnected conduit systems.

Atlas, Z. D.; Dixon, J. E.

2006-12-01

342

Parametric study of the stability margins of cable-in-conduit superconductors: experiment  

International Nuclear Information System (INIS)

In a previous experiment on the stability of cable-in-conduit superconductors, we sometimes observed multivalued stability margins, which we attributed to strong heating-induced transient flows. We proposed a schematic theory from which we derived a scaling relation for the limiting current below which the stability margin is always singlevalued. Measurements at different magnetic fields are used to test the scaling with critical temperature and resistivity. We also examine the scaling with heated length and heat pulse duration. The results of these experiments are given and compared with theory

1980-10-02

343

Méthodes et outils de la conception système couplée à la conduite de projet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Le travail que nous présentons dans ce document se situe dans le cadre de l’élaboration de méthodologies pour le développement des Systèmes. Plus particulièrement, nous proposons une méthode et des outils qui permettent le couplage de deux processus : la Conception de Produit et la Conduite de Projet. Pour la conception, nous présentons un processus qui va des exigences techniques jusqu’à l’élaboration d’un modèle logico-temporel et une représentation qui s’appuie d’ab...

Gutierrez Estrada, Citlalih

2007-01-01

344

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

Science.gov (United States)

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.

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

2007-10-02

345

Photodriven charge separation and transport in self-assembled zinc tetrabenzotetraphenylporphyrin and perylenediimide charge conduits.  

Science.gov (United States)

Zinc tetrabenzotetraphenyl porphyrin (ZnTBTPP) covalently attached to four perylenediimide (PDI) acceptors self-assembles into a ?-stacked, segregated columnar structure, as indicated by small- and wide-angle X-ray scattering. Photoexcitation of ZnTBTPP rapidly produces a long-lived electron-hole pair having a 26?Å average separation distance, which is much longer than if the pair is confined within the covalent monomer. This implies that the charges are mobile within their respective segregated ZnTBTPP and PDI charge conduits. PMID:24554617

Roznyatovskiy, Vladimir V; Carmieli, Raanan; Dyar, Scott M; Brown, Kristen E; Wasielewski, Michael R

2014-03-24

346

ITER Model Coil Tests Overview: Nb3Sn Strand Properties in Cable-in-Conduit-Conductors  

International Nuclear Information System (INIS)

During the ITER Model Coil Program two large coils and three Insert coils were built and tested. The test campaigns provided very valuable data on the Conductor in Conduit Cable (CICC) properties. The tests showed that the Nb3Sn strands in CICC behave differently than so-called witness strands, which underwent the same heat treatment. The paper describes Volt-temperature characteristics (VTC) and Volt-Ampere characteristics (VAC) measured in the tests, presents comparisons with the witness strands, and interprets the test results

2003-05-06

347

ITER Model Coil tests overview: Nb3Sn strand properties in cable-in-conduit conductors  

International Nuclear Information System (INIS)

During the ITER Model Coil program two large coils and three insert coils were built and tested. The test campaigns provided very valuable data on the cable-in-conduit conductor (CICC) properties. The tests showed that the Nb3Sn strands in CICC behave differently than so-called witness strands, which underwent the same heat treatment. The paper describes volt-temperature characteristics (VTC) and volt-ampere characteristics (VAC) measured in the tests, presents comparisons with the witness strands, and interprets the test results

2004-01-15

348

Measurement of nanosize etched pits in SiO2 optical fiber conduit using AFM  

International Nuclear Information System (INIS)

Fission fragment tracks from 252Cf have been observed in SiO2 optical fiber, using an atomic force microscope (AFM), after a very short chemical etching in hydrofluoric acid solution at normal temperature. The nuclear track starting and evolution process is followed by the AFM direct measurements on the material surface and beyond a fine layer of the surface material. The images of the scanned cones were determined observing the two predominant energies from 252Cf fission fragments and the development of the tracks in the 150 ?m diameter optical fiber conduit

2003-06-01

349

Melt and vapor characteristics in an electron beam evaporator  

Energy Technology Data Exchange (ETDEWEB)

We compare the free surface temperatures T{sub s}, calculated by two methods, in cerium or copper evaporation experiments. The first method considers properties of the melt: by an empirical law we take into account turbulent thermal convection, instabilities and craterization of the free surface. The second method considers the vapor flow expansion and connects T{sub s} to the measured terminal parallel temperature and the terminal mean parallel velocity of the vapor jet, by Direct Simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high craterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that T{sub s} and the Knudsen number at the vapor source reach a threshold when the beam power increases.

Blumenfeld, L.; Fleche, J.L.; Gonella, C. [DCC/DPE/SPEA Centre d`Etudes de Saclay, Gif-sur-Yvette (France)

1994-12-31

350

Physical rock properties in and around a conduit zone by well-logging in the Unzen Scientific Drilling Project, Japan  

Science.gov (United States)

The objective of the Unzen Scientific Drilling Project (USDP) is not only to reveal the structure and eruption history of the Unzen volcano but also to clarify the ascent and degassing mechanisms of the magma conduit. Conduit drilling (USDP-4) was conducted in 2004, which targeted the magma conduit for the 1990-95 eruption. The total drilled length of USDP-4 was 1995.75??m. Geophysical well logging, including resistivity, gamma-ray, spontaneous potential, sonic-wave velocity, density, neutron porosity, and Fullbore Formation MicroImager (FMI), was conducted at each drilling stage. Variations in the physical properties of the rocks were revealed by the well-log data, which correlated with not only large-scale formation boundaries but also small-scale changes in lithology. Such variations were evident in the lava dike, pyroclastic rocks, and breccias over depth intervals ranging from 1 to 40??m. These data support previous models for structure of the lava conduit, in that they indicate the existence of alternating layers of high-resistivity and high P-wave velocity rocks corresponding to the lava dikes, in proximity to narrower zones exhibiting high porosity, low resistivity, and low P-wave velocity. These narrow, low-porosity zones are presumably higher in permeability than the adjacent rocks and may form preferential conduits for degassing during magma ascent. ?? 2008 Elsevier B.V.

Ikeda, R.; Kajiwara, T.; Omura, K.; Hickman, S.

2008-01-01

351

Traitements de substitution et conduite automobile Opiate addiction treatment and driving  

Directory of Open Access Journals (Sweden)

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.

Gaulier Jean-Michel

2009-03-01

352

Post-esophagectomy gastric conduit cancers: treatment experiences and literature review.  

Science.gov (United States)

Esophagectomy remains the mainstay of treatment for esophageal cancer. The stomach is the commonest organ used to restore intestinal continuity after esophagectomy. Metachronous gastric cancer in the gastric conduit after esophagectomy is rare; the etiology remains unclear. Possible risk factors include Helicobacter pylori infection, biliary or pancreatic reflux and prior radiotherapy. Prognosis of these patients remains poor. Treatment of this particular entity poses unique challenges to the surgeon and oncologist. Early diagnosis by endoscopy may allow endoscopic excision such as endoscopic mucosal resection or endoscopic submucosal dissection. In more advanced cancers, surgery is difficult, reconstruction is complicated, and further radiation may not be feasible because of previous neoadjuvant therapy. In this report, four patients who developed gastric conduit cancers are presented. They were treated with either surgery alone or combined with chemoradiotherapy. All four patients were still alive after at least 21 months, with three patients currently still alive (21-48 months). The literature is also reviewed, in particular addressing the incidence, possible underlying causes, prognosis and options of treatment for this specific clinical scenario. PMID:23551754

Ho, C; Tong, D K H; Tsang, J S; Law, S Y K

2014-01-01

353

How conduit models can be used to interpret volcano monitoring data  

Science.gov (United States)

During the last decade there have been major advances in the field of volcano monitoring, but to be able to take full advantage of these advances it is vital to link the monitoring data with the physical processes that give rise to the recorded signals. To obtain a better understanding of these physical processes it is necessary to understand the conditions of the system at depth. This can be achieved through numerical modelling. We present the results of conduit models representative of a silicic volcanic system and demonstrate how processes identified and interpreted from these models may manifest in the recorded monitoring data. Links are drawn to seismicity, deformation, and gas emissions. A key point is how these data compliment each other, and through utilising conduit models we are able to interpret how these different data may be recorded in response to a particular process. This is an invaluable tool as it is far easier to draw firm conclusions on what is happening at a volcano if there are several different data sets that suggest the same processes are occurring. Some of these interpretations appear useful in forecasting potentially catastrophic changes in eruptive behaviour, such as a dome collapse leading to violent explosive behaviour, and the role of monitoring data in this capacity will also be addressed.

Thomas, M. E.; Neuberg, J. W.; Karl, S.; Collinson, A.; Pascal, K.

2012-04-01

354

Improvement of domain wall conduit properties in cobalt nanowires by global gallium irradiation  

International Nuclear Information System (INIS)

Applications based on the movement of domain walls (DWs) in magnetic nanowires (NWs) require a good DW conduit behavior, i.e. a significant difference between DW nucleation and propagation fields. In this work, we have systematically studied how this property evolves in cobalt NWs grown by focused electron beam induced deposition (FEBID) as a function of global gallium irradiation, for irradiation doses up to 1.24 × 1017 ions cm?2. Whereas for high doses the DW conduit is lost, below 6.42 × 1015 ions cm?2 the difference between the two fields increases with irradiation, becoming up to ?9 times larger than for non-irradiated wires, due to a strong increase in the nucleation field, while the propagation field remains approximately constant. This behavior stems from two effects. The first effect is a decrease in the magnetic volume of the parasitic halo around the NW, typically present in FEBID nanostructures, leading to the disappearance of weak nucleation centers. The second effect is the formation of a 20 nm outer shell with Co crystals about twice the size of those forming the NW core, causing a net increase of the local magnetocrystalline anisotropy. The results presented here are important for the potential use of magnetic NWs grown by FEBID in DW-based devices, and might also be of interest for magnetic NWs fabricated by other techniques. (paper)

2013-08-30

355

Influence of coupling current among superconducting strands on stability of cable-in-conduit conductor  

International Nuclear Information System (INIS)

Cable-in-conduit conductors (CICC) composed of multistrand superconducting cables cooled with supercritical helium are essential to superconducting magnets for fusion machines that require large current capacities, low AC losses and high rigidities. Stability margin of the Cable-in-Conduit Conductor used under the pulse field is greatly influenced by inter-strand coupling losses and current unbalance with coupling current among strands. The large transverse resistance trades sufficient current transfer among strands for low AC losses. The large stability margin is brought by sufficient current transfer, low AC losses and uniform current distribution. Then the authors should decide the reasonable value of transverse resistance corresponding to the pulse condition. In this paper, the stability is estimated by the simplified distributed constant circuits simulating unbalanced current, that is transient coupling current, and transfer current among strands. In the non-insulated strands, the inductive voltage occurred during charging in a twisted area of half pitch must be enough lower than normal voltage of local quench at the limiting current. This paper also shows that the short twisted pitch and long cables about 1,000m give not only low AC losses but also uniform current distribution during charging for insulated strands

1996-07-01

356

Operação de Rastelli utilizando-se conduto valvulado de pericárdio bovino: experiência inicial / Rastelli operation with bovine pericardium valved conduit: early experience  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O presente trabalho descreve a experiência inicial com a operação de Rastelli, utilizando-se um conduto valvulado de pericárdio bovino preservado em glutaraldeído. O enxerto consta de um conduto, que serve para reconstruir a via de saída do ventrículo direito e o tronco pulmonar, com uma válvula tri [...] cúspide suturada em seu interior sem anel de suporte, permitindo, assim, um mecanismo de fluxo unidirecional. De maio de 1986 a outubro de 1987, 5 crianças foram submetidas à operação de Rastelli empregando-se este tipo de conduto valvulado. Três eram do sexo feminino e 2, do masculino, variando a idade de 1 a 8 anos x 5). Três pacientes tinham transposição das grandes artérias, comunicação interventricular (CIV) e estenose subpulmonar. Uma criança era portadora de atresia pulmonar com CIV e de um shunt prévio tipo Waterston e, finalmente, a outra tinha um tronco arterial comum tipo II. Dois doentes faleceram de causas não relacionadas ao tipo de conduto valvulado utilizado. O conduto valvulado de pericárdio bovino preservado em glutaraldeído mostrou excelente flexibilidade, facilitando o manuseio cirúrgico e permitindo perfeita adaptabilidade dentro do saco pericárdico. A ausência de anel de suporte tem a vantagem de eliminar qualquer gradiente e de abolir o turbilhonamento do sangue - causas reconhecidas de calcificação. Abstract in english The present report describes the initial experience with the Rastelli operation utilizing a composite graft of glutaraldehyde preserved bovine pericardium. The graft is made up of a tube which serves to reconstruct the outflow tract of the right ventricle and the pulmonary artery, and an inner tricu [...] spid valve, without a supporting ring, which provides the tube with a one-way flow mechanism. From May, 1986 to October, 1987, five children were submitted to Rastelli operation utilizing this valved tube. Three were female and two male, ranging in age from 1 e to 8 years (mean 5 years). Three had transposition of the great arteries, VSD and subpulmonic stenosis, one had pulmonary atresia, VSD and a previous Waterston shunt, and one had a type II truncus arteriosus. Two patients died of causes unrelated to the type of the conduit used. The valved conduit of preserved bovine pericardium is easy to handle due to its excellent flexibility, allowing perfect adaptability inside the pericardial sac. The absence of a supporting ring abolish gradient across the conduit and turbulence which are recognized causes of calcification.

Carlos R, Moraes; Jorge V, Rodrigues; Cláudio A, Gomes; Lorella, Marinucci; Cleuza Lapa, Santos; Tereza Cristina, Coelho; Ivan de Lima, Cavalcanti.

357

Operação de Rastelli utilizando-se conduto valvulado de pericárdio bovino: experiência inicial Rastelli operation with bovine pericardium valved conduit: early experience  

Directory of Open Access Journals (Sweden)

Full Text Available O presente trabalho descreve a experiência inicial com a operação de Rastelli, utilizando-se um conduto valvulado de pericárdio bovino preservado em glutaraldeído. O enxerto consta de um conduto, que serve para reconstruir a via de saída do ventrículo direito e o tronco pulmonar, com uma válvula tricúspide suturada em seu interior sem anel de suporte, permitindo, assim, um mecanismo de fluxo unidirecional. De maio de 1986 a outubro de 1987, 5 crianças foram submetidas à operação de Rastelli empregando-se este tipo de conduto valvulado. Três eram do sexo feminino e 2, do masculino, variando a idade de 1 a 8 anos x 5. Três pacientes tinham transposição das grandes artérias, comunicação interventricular (CIV e estenose subpulmonar. Uma criança era portadora de atresia pulmonar com CIV e de um shunt prévio tipo Waterston e, finalmente, a outra tinha um tronco arterial comum tipo II. Dois doentes faleceram de causas não relacionadas ao tipo de conduto valvulado utilizado. O conduto valvulado de pericárdio bovino preservado em glutaraldeído mostrou excelente flexibilidade, facilitando o manuseio cirúrgico e permitindo perfeita adaptabilidade dentro do saco pericárdico. A ausência de anel de suporte tem a vantagem de eliminar qualquer gradiente e de abolir o turbilhonamento do sangue - causas reconhecidas de calcificação.The present report describes the initial experience with the Rastelli operation utilizing a composite graft of glutaraldehyde preserved bovine pericardium. The graft is made up of a tube which serves to reconstruct the outflow tract of the right ventricle and the pulmonary artery, and an inner tricuspid valve, without a supporting ring, which provides the tube with a one-way flow mechanism. From May, 1986 to October, 1987, five children were submitted to Rastelli operation utilizing this valved tube. Three were female and two male, ranging in age from 1 e to 8 years (mean 5 years. Three had transposition of the great arteries, VSD and subpulmonic stenosis, one had pulmonary atresia, VSD and a previous Waterston shunt, and one had a type II truncus arteriosus. Two patients died of causes unrelated to the type of the conduit used. The valved conduit of preserved bovine pericardium is easy to handle due to its excellent flexibility, allowing perfect adaptability inside the pericardial sac. The absence of a supporting ring abolish gradient across the conduit and turbulence which are recognized causes of calcification.

Carlos R Moraes

1988-08-01

358

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-04-15

359

Behavioral evaluation of regenerated rat sciatic nerve by a nanofibrous PHBV conduit filled with Schwann cells as artificial nerve graft.  

Science.gov (United States)

The aim of this study is to develop a nanofibrous polymeric nerve conduit with Schwann cells (SCs) and to evaluate its efficiency on the promotion of functional and locomotive activities in rats. The conduits were implanted into a 30-mm gap in the sciatic nerves of the rats. Four months after surgery, the rats were monitored and evaluated by behavioral analyses such as toe out angle, toe spreading analysis, walking track analysis, extensor postural thrust, open-field analysis, swimming test and nociceptive function, four months post surgery. Four months post-operatively, the results from behavioral analyses demonstrated that in the grafted groups especially in the grafted group with SCs, the rat sciatic nerve trunk had been reconstructed with functional recovery such as walking, swimming and recovery of nociceptive function. This study proves the feasibility of artificial conduit with SCs for nerve regeneration by bridging a longer defect in the rat model. PMID:24041294

Biazar, Esmaeil; Heidari Keshel, Saeed; Pouya, Majid

2013-10-01

360

Evaluation of mercury vapor in dental offices in Tehran  

Directory of Open Access Journals (Sweden)

Full Text Available Background and Aim: Dental Amalgam is a common restorative material for posterior teeth. Because of Hg content in the composition of amalgam, during the handling of material, mercury may release as vapor in the environment. Excess amount of mercury vapor can cause serious health problems in dental personnel. The aim of this investigation was to determine mercury vapor concentration in working environment of dentists in Tehran. Materials and Methods: 211 dental clinics were participated in this cross-sectional study. The clinics were randomly selected from different regions of Tehran (north, center, south, east and west. The dentists were asked to complete a questionnaire including items on demographic characteristics such as age, sex and work history, method of handling of amalgam, environmental characteristics and general health conditions. Environmental measurements of mercury vapor in dentists’ offices were done by mercury absorption tubes (Hydrar and personal pumps (SKC, 222-3, England as suggested in NIOSH method. Analysis of air samples was done by atomic absorption spectrophotometery (cold vapor. The data were analyzed by non-parametric tests (Kruskall Wallis, Mann-Whitney and Kendall.P<0.05 as the level of significance. Results: The mean mercury vapor concentration in dentists’ offices was 8.39(±9.68 µg/m³.There was no significant relationship between the urine mercury of dentists (3.107±3.95 and the air Hg vapor concentration of their offices. Using precapsulated amalgam showed significantly less Hg vapor than bulk amalgam (P=0.034. Also the surface area of working room and air Hg vapor (P=0.009 had a significant relationship (P=0.009 r=0.81. There was not any significant correlation between mercury vapor and other factors such as working hours per day and working days per week, squeezing of triturated amalgam or not, storage medium of set amalgam (water or fixer solution, mercury storage method and type of ventilation. Conclusion: The concentration of mercury vapor in dental offices' environment was lower than threshold limit value. Based on this study the type of amalgam (precapsulated or not and area of the working room had significant effect on the mercury vapor concentration of environment.

Hasani Tabatabaei M.

2007-05-01

 
 
 
 
361

Measurements of stability margins and current distribution in large-scale Nb_3Sn 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

1995-03-11

362

Investigation of Subterranean Fuel Vapor Extraction and Destruction Using a Diesel Engine.  

Science.gov (United States)

The objective of this project was to determine the feasibility of using a diesel engine as a means of fuel vapor extraction and destruction at underground contamination sites. The first priority was to determine if fuel vapors introduced into the engine v...

K. E. Stoecklein D. M. Yost

2001-01-01

363

Vaporization of lithium sulfide  

Science.gov (United States)

The vaporization of lithium sulfide has been studied by the mass spectrometric Knudsen effusion method. Over the temperature range from 1257 to 1441 K the partial pressures of Li(g), S(g), LiS(g), Li 2S(g) and S 2(g) are found to be log pLi = (9.66 ± 0.31) - (1.614 ± 0.040) 10 4/ T, logpS = (10.84 ± 0.45) - (2.117 ± 0.065) 10 4/ T, logpLiS = (10.15 ± 0.11) -(2.079 ± 0.014) 10 4/ T, logpLi2S = (10.41 ± 0.13) - (1.978 ± 0.018) 10 4/ T and logpS2 = (11.08 ± 0.36) - (2.056 ± 0.052) 10 4/ T, where the unit of pressures is pascal. From the enthalpies of reaction for the gaseous equilibria, the enthalpies of formation and the atomization energies for LiS(g) and Li 2S(g) have been determined to be ?Hf298 o( LiS, g) = (127.4 ± 7.8) kJ/ mol, ?Hf298 o( Li2S, g) = (-49.3 ± 9.6) kJ/ mol, D0o( LiS) = (308.8 ± 7.6) kJ/ mol and D0o( Li2S) = (644.3 ± 9.1) kJ/ mol, respectively.

Kimura, Hitoshi; Asano, Mitsuru; Kubo, Kenji

1981-04-01

364

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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese 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

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

365

From rainfall to spring discharge: Coupling conduit flow, subsurface matrix flow and surface flow in karst systems using a discrete-continuum model  

Science.gov (United States)

Physics-based distributed models for simulating flow in karst systems are generally based on the discrete-continuum approach in which the flow in the three-dimensional fractured limestone matrix continuum is coupled with the flow in discrete one-dimensional conduits. In this study we present a newly designed discrete-continuum model for simulating flow in karst systems. We use a flexible spatial discretization such that complicated conduit networks can be incorporated. Turbulent conduit flow and turbulent surface flow are described by the diffusion wave equation whereas laminar variably saturated flow in the matrix is described by the Richards equation. Transients between free-surface and pressurized conduit flow are handled by changing the capacity term of the conduit flow equation. This new approach has the advantage that the transients in mixed conduit flow regimes can be handled without the Preissmann slot approach. Conduit-matrix coupling is based on the Peaceman's well-index such that simulated exchange fluxes across the conduit-matrix interface are less sensitive to the spatial discretization. Coupling with the surface flow domain is based on numerical techniques commonly used in surface-subsurface models and storm water drainage models. Robust algorithms are used to simulate the non-linear flow processes in a coupled fashion. The model is verified and illustrated with simulation examples.

de Rooij, Rob; Perrochet, Pierre; Graham, Wendy

2013-11-01

366

Extracardiac conduit in total cavopulmonary connection / Conduto extracardíaco na derivação cavopulmonar total  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese OBJETIVO: Avaliar a utilização de conduto extracardíaco na confecção de derivação cavopulmonar total nos diferentes tipos de cardiopatias complexas nas quais está indicado este tipo de correção. MÉTODO: Entre maio de 2000 e janeiro de 2003, foram operados 18 pacientes, 10 do sexo masculino, com idad [...] es entre 1 e 12 anos e peso variando de 11 a 29 quilos. O diagnóstico principal foi atresia tricúspide em oito pacientes, conexão atrioventricular univentricular em oito e defeito total do septo atrioventricular desbalanceado em dois. Apenas um paciente foi operado sem cirurgia paliativa prévia. A operação foi realizada com emprego de circulação extracorpórea com temperatura acima de 32ºC orofaríngea e sem isquemia aórtica. Foram empregados, entre a veia cava inferior e a circulação pulmonar, 10 tubos de PTFE, quatro de Hemashield e quatro de pericárdio bovino, com números variando de 16 a 22mm de diâmetro. RESULTADOS: Ocorreram quatro casos de trombose no tubo, todos reoperados, com um óbito. Em um paciente, após 69 dias da operação, foi realizado "takedown" para Glenn bidirecional. Entre os 18 pacientes ocorreram três óbitos, um por trombose do tubo e dois por síndrome de baixo débito no pós-operatório imediato. CONCLUSÃO: O emprego de tubo extracardíaco já faz parte da técnica de derivação cavopulmonar total, mas sua indicação merece cuidados especiais. Abstract in english OBJECTIVE: This study evaluates a new technique of an extracardiac conduit in total cavopulmonary connection in complex congenital heart disease. METHODS: Between May 2000 and October 2002, 18 extracardiac conduit surgeries were performed. The patients' weights ranged from 11 to 29 kilograms, the ag [...] es ranged from 1 to 12 years old and 10 patients were male. There were eight patients with tricuspid atresia, eight with univentricular heart, and two with unbalanced total atrioventricular septal defect. There were 17 patients who had been submitted to a previous palliative surgery. The surgery was performed at over 32º centigrade without aortic ischemia. Ten PTFE, 4 Hemashield and 4 bovine pericardium tubes were used with diameters ranging from 16 to 22 mm. RESULTS: There were four cases of tube thrombosis and these patients were a reoperation was performed with one death. In one patient a takedown was performed on the 69th postoperative day. There were three deaths, one due to tube thrombosis and two due to low cardiac output. CONCLUSION: Extracardiac conduit is already used for total cavopulmonary connection, but despite encouraging early results, a longer follow-up is necessary to prove its real advantages.

Paulo Paredes, Paulista; Luiz Carlos Bento de, Souza; Paulo, Chaccur; Mário, Issa; Antonio Flávio Sanches de, Almeida; Ana Luiza Paulista, Guerra; Renato Tambellini, Arnoni; Paulo Henrique Dagola, Paulista; Maria Virginia Tavares, Santana.

367

Extracardiac conduit in total cavopulmonary connection Conduto extracardíaco na derivação cavopulmonar total  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: This study evaluates a new technique of an extracardiac conduit in total cavopulmonary connection in complex congenital heart disease. METHODS: Between May 2000 and October 2002, 18 extracardiac conduit surgeries were performed. The patients' weights ranged from 11 to 29 kilograms, the ages ranged from 1 to 12 years old and 10 patients were male. There were eight patients with tricuspid atresia, eight with univentricular heart, and two with unbalanced total atrioventricular septal defect. There were 17 patients who had been submitted to a previous palliative surgery. The surgery was performed at over 32º centigrade without aortic ischemia. Ten PTFE, 4 Hemashield and 4 bovine pericardium tubes were used with diameters ranging from 16 to 22 mm. RESULTS: There were four cases of tube thrombosis and these patients were a reoperation was performed with one death. In one patient a takedown was performed on the 69th postoperative day. There were three deaths, one due to tube thrombosis and two due to low cardiac output. CONCLUSION: Extracardiac conduit is already used for total cavopulmonary connection, but despite encouraging early results, a longer follow-up is necessary to prove its real advantages.OBJETIVO: Avaliar a utilização de conduto extracardíaco na confecção de derivação cavopulmonar total nos diferentes tipos de cardiopatias complexas nas quais está indicado este tipo de correção. MÉTODO: Entre maio de 2000 e janeiro de 2003, foram operados 18 pacientes, 10 do sexo masculino, com idades entre 1 e 12 anos e peso variando de 11 a 29 quilos. O diagnóstico principal foi atresia tricúspide em oito pacientes, conexão atrioventricular univentricular em oito e defeito total do septo atrioventricular desbalanceado em dois. Apenas um paciente foi operado sem cirurgia paliativa prévia. A operação foi realizada com emprego de circulação extracorpórea com temperatura acima de 32ºC orofaríngea e sem isquemia aórtica. Foram empregados, entre a veia cava inferior e a circulação pulmonar, 10 tubos de PTFE, quatro de Hemashield e quatro de pericárdio bovino, com números variando de 16 a 22mm de diâmetro. RESULTADOS: Ocorreram quatro casos de trombose no tubo, todos reoperados, com um óbito. Em um paciente, após 69 dias da operação, foi realizado "takedown" para Glenn bidirecional. Entre os 18 pacientes ocorreram três óbitos, um por trombose do tubo e dois por síndrome de baixo débito no pós-operatório imediato. CONCLUSÃO: O emprego de tubo extracardíaco já faz parte da técnica de derivação cavopulmonar total, mas sua indicação merece cuidados especiais.

Paulo Paredes Paulista

2003-09-01

368

Water Vapor - Sodium Montmorillonite Interaction.  

Science.gov (United States)

The interaction of water vapor with sodium montmorillonite was investigated with X-ray diffraction and sorption isotherm (gravimetric method) experiments. Expansion of the montmorillonite occurs in three increments. The data suggest interlayer water build...

G. L. Roderick T. Demirel

1965-01-01

369

Portable vapor diffusion coefficient meter  

Energy Technology Data Exchange (ETDEWEB)

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.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

370

Portable vapor diffusion coefficient meter  

Science.gov (United States)

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.

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

371

Scale considerations and vapor explosions  

International Nuclear Information System (INIS)

The vapor explosion potential is evaluated for the uranium oxide-water system on a scale of interest to light water reactor meltdown accident scenarios. Special emphasis is given to the necessary fragmentation and intermixing processes in connection with the pre-mixing as well as the propagation stages. It is shown that for reactor accident conditions, a large scale propagating vapor explosion with any significant damage potential can be ruled out

1984-01-01

372

Optimization of metal vapor lasers  

Energy Technology Data Exchange (ETDEWEB)

A method is proposed for the optimization of metal vapor lasers on the basis of a universal numerical calculation program and simultaneous application of an algorithm for multifactor optimization of the output parameters based on the complex Boks method and the Gel'fand--Tsetlin ravine function method. The results are given of a three-parameter optimization of a transverse-discharge copper vapor laser.

Buchanov, V.V.; Molodykh, E.I.; Tykotskii, V.V.

1983-03-01

373

Functionalized carbon nanoparticles, blacks and soots as electron-transfer building blocks and conduits.  

Science.gov (United States)

Functionalized carbon nanoparticles (or blacks) have promise as novel active high-surface-area electrode materials, as conduits for electrons to enzymes or connections through lipid films, or as nano-building blocks in electroanalysis. With previous applications of bare nanoblacks and composites mainly in electrochemical charge storage and as substrates in fuel cell devices, the full range of benefits of bare and functionalized carbon nanoparticles in assemblies and composite (bio)electrodes is still emerging. Carbon nanoparticles are readily surface-modified, functionalized, embedded, or assembled into nanostructures, employed in bioelectrochemical systems, and incorporated into novel electrochemical sensing devices. This focus review summarizes aspects of a rapidly growing field and some of the recent developments in carbon nanoparticle functionalization with potential applications in (bio)electrochemical, photoelectrochemical, and electroanalytical processes. PMID:24616339

Lawrence, Katherine; Baker, Charlotte L; James, Tony D; Bull, Steven D; Lawrence, Ruth; Mitchels, John M; Opallo, Marcin; Arotiba, Omotayo A; Ozoemena, Kenneth I; Marken, Frank

2014-05-01

374

Circuitous embolic hemorrhagic stroke: carotid pseudoaneurysm to fetal posterior cerebral artery conduit: a case report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Introduction The cervical internal carotid artery (ICA is susceptible to injury through various mechanisms, including dissection, which can lead to pseudoaneurysm formation. Pathological processes affecting the ICA, in association with an ipsilateral fetal posterior cerebral artery (PCA, resulting in parieto-occipital strokes are rarely reported. Case Presentation We present a patient with a left PCA territory, presumably embolic, stroke with early hemorrhagic transformation. The identified nidus of the embolus was a carotid artery pseudoaneurysm. Manifestations included right homonymous hemianopsia with right hemiparesis and hemisensory loss. Conclusion Our case is unique, and of clinical interest, because it illustrates both the potential anterior-posterior circulation conduit provided by a fetal origin PCA as well as the apparent early hemorrhagic transformation of embolic infarcts that can lead to further confusion from a mechanistic standpoint.

Hoque Romy

2008-02-01

375

Nb/sub 3/Sn cable-in-conduit conductor tests  

International Nuclear Information System (INIS)

Several tests have been performed on Nb/sub 3/Sn cable-in-conduit conductors in an effort to define the stability margin of the conductor to be used in the Westinghouse Large Coil Program (LCP) coil. One of the test conductors contained a 6*3/sup 4/ Nb/sub 3/Sn cable almost identical to the final LCP design; only the void fraction was different. It was not possible to quench this conductor at the limits of the test facility, 20 kA and 8-T applied field. Supporting tests were performed on smaller conductors: one of similar construction but with one-third as many composite strands and one that contained only one triplex of composite strands. Tests on both these conductors indicate that the full-size conductor should indeed have been stable against much higher energies than we were able to inject. This magnet is for fusion applications. 7 refs

1979-11-16

376

Detection of the normal zone with cowound sensors in cable-in conduit conductors  

Energy Technology Data Exchange (ETDEWEB)

Tokamaks in the future will use superconducting cable-in-conduit- conductors (CICC) in all poloidal field (PF) and toroidal field (TF) magnets. Conventional quench detection, the measurement of small resistive normal zone voltages ({lt}1 V) in the magnets will be complicated by the presence of large inductive voltages ({gt}4 kV). In the quench detection design for TPX, we have considered several different locations for internal co-wound voltage sensors in the cable cross-section as the primary mechanism to cancel this inductive noise. The Noise Rejection Experiment (NRE) at LLNL has been designed to evaluate which internal locations will produce the best inductive- noise cancellation, and provide us with experimental data for comparison with previously developed theory. The details of the experiments and resulting data are presented and analyzed.

Martovetsky, N.N.; Chaplin, M.R.

1996-07-30

377

Detection of the normal zone with cowound sensors in cable-in conduit conductors  

International Nuclear Information System (INIS)

Tokamaks in the future will use superconducting cable-in-conduit- conductors (CICC) in all poloidal field (PF) and toroidal field (TF) magnets. Conventional quench detection, the measurement of small resistive normal zone voltages (4 kV). In the quench detection design for TPX, we have considered several different locations for internal co-wound voltage sensors in the cable cross-section as the primary mechanism to cancel this inductive noise. The Noise Rejection Experiment (NRE) at LLNL has been designed to evaluate which internal locations will produce the best inductive- noise cancellation, and provide us with experimental data for comparison with previously developed theory. The details of the experiments and resulting data are presented and analyzed

1996-08-25

378

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

2005-01-01

379

Mechanical properties of the prototype cable-in-conduit conductors for NET  

International Nuclear Information System (INIS)

This paper reports that the mechanical behavior of a Nb3Sn cable-in-conduit conductor after the heat treatment is a crucial characteristic to assess the conductor performances in a big coil under the operating loads. On the other hand, the mechanical properties of the conductor and its components before the heat treatment are important to lay out the right tools and machinery of the manufacturing and winding process. Extensive mechanical test on full size and subsize cables, with and without steel jacket, at liquid nitrogen and liquid helium temperature have been carried out on the three prototype CIC conductors manufactured by the industry. The measurements include: tensile tests from the basis strand to the full size conductor, compression tests of cable and jacket, bending test, friction test between cable and jacket transversal and axial cable loading with hysteresis measurements

1992-01-01

380

Analysis of transient thermally-induced convection of supercritical helium in a conduit  

Energy Technology Data Exchange (ETDEWEB)

This work investigates the thermally-induced transient flow and heat transfer in cable-in-conduit conductors (CICC) cooled with initially stagnant supercritical helium. Prior studies have demonstrated that thermally-induced flow results in a high heat transfer coefficient and a large thermal stability margin. Accurate prediction of the stability margin requires a quantitative description of the variation of heat transfer with heat flux. This study focuses on the heat transfer/heat flux relationship and on the basic mechanisms governing the early stages of transient heating. The present modeling divides the problem into two parts: a low-heat flux regime and a high-heat flux regime. Results from the present models indicate that the heat transfer coefficient exhibits a minimum, as observed experimentally in a previous study, and that, in general, heat transfer can be considerably enhanced by using a highly compressible fluid like supercritical helium.

Phelan, P.E.; Kuo, S.M.; Tien, C.L.

1989-03-01

 
 
 
 
381

Trial manufacture of a 30 m cable-in-conduit-conductor (CICC) for HT-7U  

International Nuclear Information System (INIS)

The author reports the working procedure of a 30 m cable-in-conduit-conductor (CICC), which has been first successfully fabricated by a working group of IPP in Jan. 1999. A series of problems along with measures for their solution were put forward at the request of engineering design on the basis of an in-depth understanding of the basic performance of the related techniques for the manufacture of CICC. Through a full-scale trial manufacture of a 30 m conductor including a series of test on performance technology such as tube-tube butted welding, pulling, equating, pre-bending and take-up, the trial manufacture of the first home-made CICC conductor has been accomplished, demonstrating that the fabrication of a long-length CICC is entirely possible theoretically and practically through authors' efforts. Results and problems concerned in the trial fabrication are also presented

2000-06-01

382

Thymic medullar conduits-associated podoplanin promotes natural regulatory T cells.  

Science.gov (United States)

Podoplanin, a mucin-like plasma membrane protein, is expressed by lymphatic endothelial cells and responsible for separation of blood and lymphatic circulation through activation of platelets. Here we show that podoplanin is also expressed by thymic fibroblastic reticular cells (tFRC), a novel thymic medulla stroma cell type associated with thymic conduits, and involved in development of natural regulatory T cells (nTreg). Young mice deficient in podoplanin lack nTreg owing to retardation of CD4(+)CD25(+) thymocytes in the cortex and missing differentiation of Foxp3(+) thymocytes in the medulla. This might be due to CCL21 that delocalizes upon deletion of the CCL21-binding podoplanin from medullar tFRC to cortex areas. The animals do not remain devoid of nTreg but generate them delayed within the first month resulting in Th2-biased hypergammaglobulinemia but not in the death-causing autoimmune phenotype of Foxp3-deficient Scurfy mice. PMID:23912054

Fuertbauer, Elke; Zaujec, Jan; Uhrin, Pavel; Raab, Ingrid; Weber, Michele; Schachner, Helga; Bauer, Miroslav; Schütz, Gerhard J; Binder, Bernd R; Sixt, Michael; Kerjaschki, Dontscho; Stockinger, Hannes

2013-01-01

383

Numerical modeling of thermal behavior of fluid conduit flow with transport delay  

Energy Technology Data Exchange (ETDEWEB)

Fluid mass and energy flows in air-conditioning systems vary with the changing output demand. In lengthy or complex ductwork and pipework, the accuracy in simulating the dynamic network behavior is greatly affected by the accuracy in modeling the radial energy losses and the axial transport lag. Transport delay consideration is also vital in the study of heat exchanger dynamics. This paper reviews the development of transport delay models in fluid conduit flow. A new numerical model is recommended in which the thermal behavior of fluid elements can be traced per physical distance traveled in unit time step. Justifications by sensitivity and frequency response analyses were performed. The results of analytical, experimental, as well as intermodel comparisons demonstrate the promising accuracy of the numerical model introduced.

Chow, T.T. [City Univ. of Hong Kong (Hong Kong). Div. of Technology; Ip, F.; Dunn, A. [Univ. of Hong Kong (Hong Kong). Faculty of Engineering; Tse, W.L. [China Light and Power Co., Ltd., Hong Kong (Hong Kong)

1996-12-31

384

Parametric study of the stability margin of cable-in-conduit superconductors: theory  

International Nuclear Information System (INIS)

Recently, Lue, Miller, and Dresner reported that the stability margin of cable-in-conduit superconductors is multivalued for certain combinations of transport current, ambient helium pressure, and externally imposed helium flow. There is a limiting transport current below which the stability margin is single-valued and equal to the upper stability margin. This theory is used here to determine the scaling of the limiting transport current with critical temperature, ambient helium temperature, resistivity of copper, length of the heated zone, duration of the heat pulse, hydraulic diameter of the helium-filled part of the cable, volume fraction of copper in the metal, and volume fraction of metal in the cable. Combined with experimental data, the scaling relation provides a sound basis for design

1980-10-02

385

Laser perforated accordion nerve conduit of poly(lactide-co-glycolide-co-?-caprolactone).  

Science.gov (United States)

Accordion nerve conduit of poly(lactide-co-glycolide-co-?-caprolactone) with perforations was developed by excimer laser processing. We evaluated its in vivo function for nerve repairing and discussed the influence of pore size and density. It was found that perforations help inner nerve regeneration remarkably, which effect is unrelated to pore size or density, and is not parallel with revascularization increment. Inducing of permeability only to allow substance exchange but not vessel ingrowth could facilitate nerve regeneration too. Perforating micropores with the size of 100 ?m and the density of 25/cm provides permeability and vessel ingrowth both, therefore promotes the axon extension the best, larger, and more pores do not advance axon regeneration more. PMID:24616166

Fukuda, Yutaka; Wang, Wei; Ichinose, Shizuko; Katakura, Hiroshi; Mukai, Tomokazu; Takakuda, Kazuo

2014-05-01

386

Superconducting coil with pure copper wires for thermal protection outside cable-in-conduit conductors  

International Nuclear Information System (INIS)

In order to realize a low cost toroidal field (TF) superconducting coil system for tokamak fusion reactors, the design of TF superconducting coil with a copper coil in place of pure copper wires which are needed for the thermal protection within cable-in-conduit (CIC) conductors is considered. This consideration is carried out under the condition that hot spot temperature of conductor is less than 250 K and a plasma-confinement vacuum vessel has no damage during the TF coil fast discharge. As the result, it is found that the conductor area is reduced by 35% and the copper coil is installed into the original coil case together with a TF coil winding. An external resistor system is reduced to around 30% of the original system because 70% of magnetic energy (40 GJ) stored in the ITER TF coil is dissipated into the copper coil during the fast discharge

2003-09-01

387

Thermal hydraulic characteristics of a prototype CEA cable-in-conduit conductor  

International Nuclear Information System (INIS)

The thermal hydraulic characteristics of a prototype CEA Cable-in-Conduit Conductor (CICC) have been studied in steady state and transient conditions. The supercritical helium velocity in the central channel was measured with a Pitot tube located at the down stream end of the conductor. An inductive heater, located at the center of the conductor, initiated thermally induced transient flow of the helium within the conductor. The induced flow velocity was measured as a function of Reynolds number and heat input. A calorimetric calibration technique was used to estimate the total heat input to the conductor. In a separate part of the experiment, a thermometer array was installed in the central channel to record the helium temperature. The associated reduction of central channel flow area significantly affects the thermal hydraulic characteristics of the conductor

1995-07-17

388

Stability characteristics of a cable-in-conduit conductor by subcooled supercritical helium  

International Nuclear Information System (INIS)

The stability and limiting current of a NbTi forced-cooled superconducting coil have been investigated experimentally and analytically at the subcooled condition below 4.5 K. The test coil was wound in a one layer solenoid from a cable-in-conduit type conductor of critical current of 5.1 kA at 4.2 K and 6.5 T, whose total length was 10 m. It was installed in the bore of a back-up superconducting magnet that provided field 8 T at the test coil. The stability margin of the coil as a function of normalized current (transport current/critical current) were measured. The results are compared with the formula proposed by Dresner and reported to predictions of stability margin and limiting current at subcooled condition below 4.5 K

1994-07-01

389

Recurrent cervical esophageal stenosis after colon conduit failure: Use of myocutaneous flap  

Directory of Open Access Journals (Sweden)

Full Text Available A 53-year-old male developed cervical esophageal stenosis after esophageal bypass surgery using a right colon conduit. The esophageal bypass surgery was performed to treat multiple esophageal strictures resulting from corrosive ingestion three years prior to presentation. Although the patient underwent several endoscopic stricture dilatations after surgery, he continued to suffer from recurrent esophageal stenosis. We planned cervical patch esophagoplasty with a pedicled skin flap of sternocleidomastoid (SCM muscle. Postoperative recovery was successful, and the patient could eat a solid meal without difficulty and has been well for 18 mo. SCM flap esophagoplasty is an easier and safer method of managing complicated and recurrent cervical esophageal strictures than other operations.

Young Jo Sa

2013-01-01

390

Thermal-hydraulic simulation on cable-in-conduit-conductor for KSTAR superconducting magnets  

International Nuclear Information System (INIS)

In order to study the thermal-hydraulic behavior of the cable-in-conduit-conductor (CICC), a numerical model has been developed. In the model, the high heat transfer approximation between superconducting strands and supercritical helium is adopted. The strong coupling of heat transfer at the front of normal zone generates a contact discontinuity in temperature and density. In order to obtain the converged numerical solutions, a moving mesh method is used to capture the contact discontinuity in the short front region of the normal. The coupled equation is solved using the finite element method with the artificial viscosity term. Details of the numerical implementation are discussed. Comparing the results with GANDALF and QSAIT, the validation of the code is performed. The quench study of CICC for the KSTAR TF coils is also performed. (author)

2000-10-01

391

Coupling losses in cable-in-conduit conductors for LHD poloidal coils  

International Nuclear Information System (INIS)

Coupling losses in Large Helical Device (LHD) poloidal coils have been measured during operations with three different waveforms. The superconductors of the poloidal coils are cable-in-conduit conductors (CICC) cooled by supercritical helium. In the experiments, the operating currents were simultaneously changed with a given waveform, and the enthalpy increase due to the losses was observed at the inlet and outlet of the helium coolant. Inter-strand coupling currents through resistive contact points mainly caused the losses. Time constants of the coupling currents are estimated by using analytical expressions with a circuit model. The results indicate a broad distribution of the time constants from the order of 10-1000 s

2003-01-01

392

Numerical Simulation of the Mechanical Behavior of ITER Cable-In-Conduit Conductors  

International Nuclear Information System (INIS)

The unexpected degradations of current carrying capacity of Nb3Sn Cable-In-Conduit Conductors are attributed to be mechanical in origins. As a result, the prediction of conductor's performances asks for the assessment of the local strain state of the Nb3Sn superconducting strands inside cables. For this purpose, a finite element modeling, specially developed for the simulation of cable mechanics, is presented in this paper. The presented mechanical model allows simulating the conductors' service life from manufacturing to operating conditions by describing the evolution of strains and stresses within each individual strand. The distributions of axial strains within strands, obtained from simulation results of both thermal and Lorentz loadings, could help characterize the influence of design parameters. (authors)

2010-01-01

393

Stability of cable-in-conduit internally cooled superconductors subject to local disturbance  

International Nuclear Information System (INIS)

A likely source of a quench in cable-in-conduit internally cooled superconductors (CCICS) is frictional heating due to strand motion in the cable. Most previous studies on CCICS stability evaluate the amount of energy needed to quench the conductor by assuming that the disturbance ene