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1

Mesospheric water vapor measurements from Penn State - Monthly mean observations (1984-1987)  

Science.gov (United States)

Mesospheric water vapor measurements obtained by ground-based microwave spectroscopy between November 1984 and July 1987 are examined. Monthly mean water vapor profiles are used to establish annual and interannual variability. The results suggest that the seasonal variation of upper mesospheric water vapor is dominated by an annual component with low mixing ratios in winter and high mixing ratios in summer. The results are compared with those reported by Bevilacqua et al. (1987).

Bevilacqua, Richard M.; Olivero, John J.; Croskey, Charles L.

1989-01-01

2

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

Science.gov (United States)

... Alternative means of emission limitation: Connectors in gas/vapor service and light...CONTINUED) National Emission Standards for Hazardous... Alternative means of emission limitation: Connectors in gas/vapor service and...

2010-07-01

3

Method and device for controlling tank vapors on a petroleum storage tank  

International Nuclear Information System (INIS)

This patent describes a method for controlling tank vapors on a petroleum storage tank of the type having a tank vapor line running to a suction scrubber, the scrubber being connected by a conduit to a reciprocating compressor which, in turn, is connected to a compressed vapor discharge line for passing compressed vapors to a gas sales line. It comprises: operating the reciprocating compressor to draw tank vapor through the suction scrubber and through the reciprocating compressor to discharge vapor through the compressed vapor discharge line; installing pneumatic control means in the tank vapor line for controlling the flow of tank vapors to the suction scrubber; and providing the pneumatic control valve means with pilot means for controlling the operation of the control valve means

4

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

5

Seal arrangement for intersecting conduits  

International Nuclear Information System (INIS)

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

6

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

7

Gastric conduit perforation.  

Science.gov (United States)

As patients with carcinoma of the esophagus live longer, complications associated with the use of a gastric conduit are increasing. Ulcers form in the gastric conduit in 6.6% to 19.4% of patients. There are a few reports of perforation of a gastric conduit in the English literature. Almost all of these were associated with serious complications. We report a patient who developed a tension pneumothorax consequent to spontaneous perforation of an ulcer in the gastric conduit 7 years after the index surgery in a patient with carcinoma of the gastroesophageal junction. He responded well to conservative management. Complications related to a gastric conduit can be because of multiple factors. Periodic endoscopic surveillance of gastric conduits should be considered as these are at a higher risk of ulcer formation than a normal stomach. Long term treatment with proton pump inhibitors may decrease complications. There are no guidelines for the treatment of a perforated gastric conduit ulcer and the management should be individualized. PMID:25133156

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

2014-08-16

8

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

9

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

10

Seal between metal and ceramic conduits  

Energy Technology Data Exchange (ETDEWEB)

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

Underwood, Richard Paul; Tentarelli, Stephen Clyde

2015-02-03

11

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

12

Portable conduit retention apparatus for releasably retaining a conduit therein  

Science.gov (United States)

Portable conduit retention apparatus for releasably retaining a conduit therein. The apparatus releasably retains the conduit out of the way of nearby personnel and equipment. The apparatus includes a portable support frame defining a slot therein having an open mouth portion in communication with the slot for receiving the conduit through the open mouth portion and into the slot. A retention bar is pivotally connected to the support frame adjacent the mouth portion for releasably retaining the conduit in the slot. The retention bar freely pivots to a first position, so that the mouth portion is unblocked in order that the conduit is received through the mouth portion and into the slot. In addition, the retention bar freely pivots to a second position, so that the mouth portion is blocked in order that the conduit is retained in the slot. The conduit is released from the slot by pivoting the retention bar to the first position to unblock the mouth portion and thereafter manipulating the conduit from the slot and through the mouth portion. The apparatus may further include a mounting member attached to the support frame for mounting the apparatus on a vertical support surface. Another embodiment of the apparatus includes a shoe assembly of predetermined weight removably connected to the support frame for resting the apparatus on a floor in such a manner that the apparatus is substantially stationary on the floor.

Metzger, Richard H. (West Seneca, NY)

1998-01-01

13

30 CFR 18.39 - Hose conduit.  

Science.gov (United States)

...1 2010-07-01 2010-07-01 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...

2010-07-01

14

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

15

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)

16

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

17

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

18

Particle Loss in Sampling Conduits  

International Nuclear Information System (INIS)

Loss of particles in long sampling conduits may cause serious underestimation of airborne radioactivity levels, particularly for particles under 0.01 ?m and over 1 ?m diam. The smaller particles are lost by diffusion and the larger ones by gravity settling. Losses can also occur from turbulent diffusion and impaction at high sampling rates, and from electrical effects if the conduits are made of non conductors. A single equation for loss of particles by diffusion in conduits has been developed, superseding the set of two equations which has been used since 1949, Equations giving loss due to gravity settling in tubes, developed independently by Natanson and by Thomas are shown to be identical, and experimental confirmation of the equations has been obtained. From these equations graphs were developed which permit a rapid estimation of losses as a function of particle size, flow rate, and conduit dimensions. Recommendations are made for design and operation of sampling conduits to minimize losses. A principal recommendation is that the flow rate should be 150 times the conduit diameter. (author)

19

Acoustic signal propagation characterization of conduit networks  

Science.gov (United States)

Analysis of acoustic signal propagation in conduit networks has been an important area of research in acoustics. One major aspect of analyzing conduit networks as acoustic channels is that a propagating signal suffers frequency dependent attenuation due to thermo-viscous boundary layer effects and the presence of impedance mismatches such as side branches. The signal attenuation due to side branches is strongly influenced by their numbers and dimensions such as diameter and length. Newly developed applications for condition based monitoring of underground conduit networks involve measurement of acoustic signal attenuation through tests in the field. In many cases the exact installation layout of the field measurement location may not be accessible or actual installation may differ from the documented layout. The lack of exact knowledge of numbers and lengths of side branches, therefore, introduces uncertainty in the measurements of attenuation and contributes to the random variable error between measured results and those predicted from theoretical models. There are other random processes in and around conduit networks in the field that also affect the propagation of an acoustic signal. These random processes include but are not limited to the presence of strong temperature and humidity gradients within the conduits, blockages of variable sizes and types, effects of aging such as cracks, bends, sags and holes, ambient noise variations and presence of variable layer of water. It is reasonable to consider that the random processes contributing to the error in the measured attenuation are independent and arbitrarily distributed. The error, contributed by a large number of independent sources of arbitrary probability distributions, is best described by an approximately normal probability distribution in accordance with the central limit theorem. Using an analytical approach to model the attenuating effect of each of the random variable sources can be very complex and may be intractable. A tractable approach is to develop an empirical model of the attenuation that has a stochastic component of a finite mean and variance to account for the random variable error akin to addition of a normally distributed random variable shadowing component in the path loss models of radio frequency (RF) wireless communication channels. This approach forms the crux of the present study. To develop an empirical model, a large number of measurements in conduit networks were made in the field and in a laboratory test set up to measure the variability of attenuation with variation in four parameters. These parameters include distance of the receiver from the source, frequency, numbers and lengths of side branches. Variation in signal attenuation with distance at each transmitted frequency is predicted by using linear regression through the scatter plot of the measured data. Variations in signal attenuation due to change in frequency, number and lengths of side branches are measured in the field and laboratory tests by comparing the reference transmitted pressure with the received pressure at either the open end or at some distance away from the source along the conduit length. Residuals between measured and predicted sound pressure levels are computed and tested for normal probability distribution through a graphical method as well as a statistical goodness of fit test for quantifiable results. The findings indicate that an empirical model of signal attenuation, which includes a normally distributed random variable component to account for random variable errors in the attenuation measurements, gives a more accurate prediction of received acoustic signal strength in a conduit compared to existing theoretical models.

Khan, Muhammad Safeer

20

Method for Water Vapor Profile Retievals by Means of Minimizing Difference Between Estimated and Actual Brightness Temperatures Derived from AIRS data and Radiative Transfer Model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Method for water vapor profile retrievals by means of minimizing difference between estimated and actual brightness temperatures derived from AIRS data and radiative transfer model is proposed. Initial value is determined by linearized radiative transfer equation. It is found that this initial value determination method makes improvement of estimation accuracy together with reducing convergence time

Kohei Arai

2013-01-01

 
 
 
 
21

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

22

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)

23

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

24

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

25

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

Energy Technology Data Exchange (ETDEWEB)

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, E-mail: n.abidi@ttu.edu

2013-12-15

26

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

27

Method and apparatus for inspecting conduits  

Science.gov (United States)

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

28

Peripheral nerve conduits: technology update  

Directory of Open Access Journals (Sweden)

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

Arslantunali D

2014-12-01

29

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

30

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

Energy Technology Data Exchange (ETDEWEB)

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

Greiner, L.

1977-01-01

31

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

32

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

33

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

34

77 FR 22480 - Conduit Financing Arrangements; Correction  

Science.gov (United States)

...2011 (76 FR 76895) providing guidance on conduit financing arrangements. The final regulations apply to multiple-party financing arrangements that are effected through disregarded entities, and are necessary in order to determine which of...

2012-04-16

35

76 FR 76895 - Conduit Financing Arrangements  

Science.gov (United States)

...contains final regulations relating to conduit financing arrangements. The final regulations apply to multiple-party financing arrangements that are effected through disregarded entities, and are necessary in order to determine which of...

2011-12-09

36

Method and device for isotope-selective excitation of gaseous or vaporous uranium hexafluoride by means of laser radiation  

International Nuclear Information System (INIS)

The light generated by triple Raman scattering of an iodine laser in liquid and/or solid N has a width of line corresponding nearly exactly to the half-width of the relevant absorption lines of the subcooled UF6. By a corresponding shift of frequencies this line isotope-specifically overlaps with an absorption line of the UF6 molecules, so that these become excited and capable of being separated by means of physical and chemical methods of separation. (DG)

37

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.)

38

Small hydro conduit optimization with differential calculus  

Energy Technology Data Exchange (ETDEWEB)

Differential calculus methods were used to simplify the calculation of optimizing a power plant conduit. An equation for the costs and lost benefits as a function of conduit diameter was proposed. A nine-step procedure was presented which included a method to take into account different operating modes, peaking or base loaded. Two working examples, one based on a proposed power plant in the Northwest Territories and one on a high pressure steel penstock in South America were presented. 5 refs.

Gordon, J.L.

1998-05-01

39

Methods of measuring pumpage through closed-conduit irrigation systems  

Science.gov (United States)

Methods of measuring volumes of water withdrawn from the Snake River and its tributaries and pumped through closed-conduit irrigation systems were needed for equitable management of and resolution of conflicts over water use. On the basis of evaluations and field tests by researchers from the University of Idaho, Water Resources Research Institute, Moscow, Idaho, an impeller meter was selected to monitor pumpage through closed-conduit systems. In 1988, impeller meters were installed at 20 pumping stations along the Snake River between the Upper Salmon Falls and C.J. Strike Dams. Impeller-derived pumpage data were adjusted if they differed substantially from ultrasonic flow-meter- or current-meter-derived values. Comparisons of pumpage data obtained by ultrasonic flow-meter and current-meter measurements indicated that the ultrasonic flow meter was a reliable means to check operation of impeller meters. The equipment generally performed satisfactorily, and reliable pumpage data could be obtained using impeller meters in closed-conduit irrigation systems. Many pumping stations that divert water from the Snake River for irrigation remain unmeasured; however, regression analyses indicate that total pumpage can be reasonably estimated on the basis of electrical power consumption data, an approximation of total head at a pumping station, and a derived coefficient.

Kjelstrom, L.C.

1991-01-01

40

Predictors and outcomes of right ventricular outflow tract conduit rupture during percutaneous pulmonary valve implantation: a multicentre study.  

Science.gov (United States)

Aims: Conduit rupture is a serious complication encountered during percutaneous pulmonary valve implantation (PPVI). We sought to evaluate the incidence and predictors of conduit rupture during right ventricular outflow tract (RVOT) transcatheter treatment. Methods and results: All consecutive patients who underwent transcatheter RVOT treatment from May 2008 to December 2011 were prospectively studied. Baseline demographics along with incidence, predictors and outcomes of conduit rupture with various transcatheter therapies were reviewed. Conduit rupture occurred in nine out of 99 patients (9.09%). All conduit ruptures occurred during balloon dilatation. Significant risk factors included heavy calcification (pballoons, balloon diameter, and overexpansion of conduit statistically failed to show any association. All patients were managed in the cardiac catheterisation laboratory. There were no delayed complications during a mean follow-up period of 2.3±0.95 years. Conclusions: Conduit rupture is a serious complication. Heavy calcification and homograft conduit were significant predictors. Immediate diagnosis with the use of targeted interventional therapies should be attempted before proceeding with PPVI. PMID:25244126

Boudjemline, Younes; Malekzadeh-Milani, Sophie; Patel, Mehul; Thambo, Jean-Benoit; Bonnet, Damien; Iserin, Laurence; Fraisse, Alain

2014-09-22

 
 
 
 
41

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2007-06-15

42

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)

43

Sensing turbulent flow and heat transport in a cave conduit  

Science.gov (United States)

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

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

2008-12-01

44

Phase separation phenomena in branching conduits. Topical report Dec 78-Dec 81  

International Nuclear Information System (INIS)

The analysis of Light Water Reactor (LWR) Loss-of-Coolant Accidents (LOCA's) requires that one be able to accurately calculate the two-phase flow splits in complex, branching conduits. The purpose of this study is to provide a general method for calculating the phase separation in a branching conduit. The degree of phase separation of a two-phase (air/water) mixture flowing through a plexiglas tee test section was measured. In addition, flow visualization, using high speed photography, was performed. The experimental design considerations, error analysis and the dependence of the observed phase separation on global parameters, such as inlet quality, mass flux and separation angle, are discussed. The pressure gradients were measured along the various conduits and the differential pressure was obtained at the tee junction by extrapolation. It was found that the degree of phase separation was quite pronounced, with the vapor phase preferentially separating into the branch. Using these data, a physically-based empirical model was developed with which to calculate the phasic distribution of a subsonic two-phase mixture in the downstream branches of a branching conduit

45

26 CFR 1.7701(l)-1 - Conduit financing arrangements.  

Science.gov (United States)

...Internal Revenue 13 2010-04-01 2010-04-01 false Conduit financing arrangements. 1.7701(l)-1 Section 1...TAXES General Actuarial Valuations § 1.7701(l)-1 Conduit financing arrangements. Section 7701(l)...

2010-04-01

46

Preventing or repairing ileal conduit herniation?  

Science.gov (United States)

We enjoyed the video vignette clearly demonstrating the benefits of a laparoscopic modified Sugarbaker repair for ileal conduit herniation (1), yet could not help but be reminded of Benjamin Franklin's (1706-1790) quote "an ounce of prevention is worth a pound of cure". This article is protected by copyright. All rights reserved. PMID:25472743

Bosanquet, David C; Mainwaring, Anna; Rutka, Olga; Stephenson, Brian M; Carter, Adam C

2014-12-01

47

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

48

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

49

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

International Nuclear Information System (INIS)

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

50

18 CFR 358.6 - No conduit rule.  

Science.gov (United States)

...2010-04-01 2010-04-01 false No conduit rule. 358.6 Section 358.6...STANDARDS OF CONDUCT § 358.6 No conduit rule. (a) A transmission provider is prohibited from using anyone as a conduit for the disclosure of...

2010-04-01

51

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...2010-04-01 2010-04-01 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...

2010-04-01

52

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

Science.gov (United States)

During routine cytopathological evaluation of urines for malignant cells we have occasionally noticed vegetable cells that were only present in patients with Bricker ileal conduit. We wanted to identify the means and sources of contamination of urinary samples from these patients. During the period between May and November 2010, 637 urinary samples were routinely evaluated for malignant cells. Among them were 13 urinary samples from Bricker ileal conduit which we rescreened. We prepared all urinary samples by membrane filtration and stained them according to Papanicolaou. Subsequently, we prepared samples from ostomy adhesives made by Coloplast and by ConvaTec which are used to secure the ostomy bag onto urostomy. We also took samples from different constituents (hydrocolloids) of ostomy adhesives. On the cytopathological review, we found vegetable cells along with intestinal mucosa cells in urinary samples of seven patients with Bricker ileal conduit. With the light microscopic examination of the samples prepared from different ostomy adhesives, we found vegetable cells only in Coloplast adhesives. In preparations of hydrocolloids, we found vegetable cells only in guar gum. They were morphologically identical to those found in urine samples of patients with Bricker ileal conduit and in Sensura and Sensura Xpro (Coloplast) ostomy adhesives. We determined that the origin of vegetable cells in urines from Bricker ileal conduit is the ostomy adhesive. The vegetable cells differ from human intestinal epithelial cells regarding size, shape, and color so it is difficult to misinterpret them as dysplastic cells. PMID:23687081

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

2014-02-01

53

EMP/EMI hardening of electrical conduit systems  

Science.gov (United States)

Properly designed and installed conduit systems can provide an effective EMP/EMI hardening technique for fixed facility construction. This report presents the results of a CERL study to provide design criteria and to conduct hardness assessments for such shielded systems. Leakage mechanisms are identified, and techniques for determining signal levels coupled to conductors inside conduit systems are presented. EMP shielding properties of conduit hardware items are analyzed and some experimental EMP hardened conduit hardware items evaluated. Finally, a number of 'in situ' test techniques for identifying and locating EMP-related defects in an installed conduit system are assessed.

Nielsen, P. H.

1981-09-01

54

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

55

EMP injection on conduit entries, type Brattberg  

Science.gov (United States)

The ability of conduit entries to divert EMP currents from the cables to a shielding structure was studied. The gas tight entry has a brass plate connecting the cable sheath and cable shield with the shielding structure. The measurements were made at different values of the time derivative of the current. Results show that the diverting properties of the cable entries are satisfactory in most cases.

Borgefalk, O.; Dikvall, T.

1984-05-01

56

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

57

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 ? for 36Ar?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 84–102°K. Although the agreement is within twice the statistical scatter of the present data, the present results for the ln? are systematically 5% lower than calculations from vapor pressure data. It is shown that T2 ln? is a linear function of (?c??g), the density difference between the liquid and vapor, in the range 84–120°K. The fractionation factor approaches zero at the critical temperature with a nonclassical critical index equal to 0.42±0.02.??2Uc?/?c in liquid argon is derived from the experimental fractionation data and calculations of ??2Ug?/?g for a number of potential functions for gaseous argon.

Phillips, J. T.; LinderstrØm-Lang, C. U.

1972-01-01

58

Thermal damping and retardation in karst conduits  

Science.gov (United States)

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

Luhmann, A. J.; Covington, M. D.; Myre, J. M.; Perne, M.; Jones, S. W.; Alexander, E. C., Jr.; Saar, M. O.

2014-08-01

59

Thermal damping and retardation in karst conduits  

Science.gov (United States)

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

Luhmann, A. J.; Covington, M. D.; Myre, J. M.; Perne, M.; Jones, S. W.; Alexander, E. C., Jr.; Saar, M. O.

2015-01-01

60

Thermal damping and retardation in karst conduits  

Directory of Open Access Journals (Sweden)

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

A. J. Luhmann

2014-08-01

 
 
 
 
61

DEFORMATION OF SCORIA CONE BY CONDUIT PRESSURIZATION  

Energy Technology Data Exchange (ETDEWEB)

A simplified mechanical model is used to simulate the deformation of a scoria cone due to pressurization of magma in a feeder conduit. The scoria cone is modeled as consisting of a cone of stabilized scoria with an axial region of loose scoria (height h{sub 1}), all overlying a vertically oriented cylindrical conduit intruded into rhyolite tuff country rock. For our analyses, the conduit is filled with basalt magma, usually with the upper length (h{sub 2}) solidified. The style of deformation of the cone depends on both h{sub 1} and h{sub 2}. If magma is prevented from hydrofracturing out of the conduit (as, for example, might be the case if the magma is surrounded by a solidified, but plastically deformable layer acting as a gasket backed up by the brittle country rock) pressures in the magma can build to 10s of MPa. When h{sub 1} is 100 m, not unusual for a small isolated basaltic cinder cone, the magma pressure needed to destabilize the cone when molten magma extends all the way to the original ground surface (h{sub 2} = 0) is only about one-third of the pressure when the upper part of the conduit is solidified (h{sub 2} = 25m). In the former case, almost the entire upper third of the cone is at failure in tension when the configuration becomes unstable. In the latter case, small portions of the surface of the cone are failing in tension when instability occurs, but a large volume in the central core of the cone is failing in shear or compressions. These results may provide insight into the status of volcanic plumbing, either past or present, beneath scoria cones. Field observations at the Lathrop Wells volcano in southern Nevada identify structures at the outer edge just below the crater rim that appear to be inward-dipping listric normal faults. This may indicate that, near the end of its active stage, the cone was close to failing in this fashion. A companion paper suggests that such a failure could have been quite energetic had it occurred.

E.S. Gaffney; B. Damjanac; D. Krier; G. Valentine

2005-08-26

62

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

63

System and method measuring fluid flow in a conduit  

Science.gov (United States)

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

64

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

65

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

66

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

67

Measurement of the friction of thin films by means of a quartz microbalance in the presence of a finite vapor pressure  

International Nuclear Information System (INIS)

In recent years, the quartz-crystal microbalance technique (QCM) has been succesfully applied to the field of nanotribology. In this paper we examine the effect of a finite vapor pressure on the accuracy of thin-film friction measurements taken with a QCM by solving the Navier-Stokes equation of the combined system quartz-crystal-adsorbed film-bulk vapor. We also discuss the details of the calibration procedure of the QCM carried out at both room temperature and low temperature, and describe the data acquisition and analysis specific to tribological applications. Finally, we present some preliminary data of the friction of a Kr monolayer adsorbed on gold at low temperatures that show the sliding of the film

68

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?Nanofiber 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

69

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

70

SQUG cable tray and conduit evaluation procedure  

International Nuclear Information System (INIS)

Cable tray and conduit systems for electrical cables are a common feature and industrial facilities. They have an excellent performance history in past strong earthquake, even though they are rarely designed for earthquakes. Considerable data have been gathered on their performance in earthquakes and in shake table testing. The data have been used to develop a procedure for the verification of the seismic adequacy of cable tray and conduit systems in operating nuclear plants. The procedure is discussed in this paper. It will result in substantial savings, such as reduced engineering effort, fewer modifications of existing hardware, and simpler documentation, relative to alternate procedures like dynamic analysis of shake table testing. The procedure ensures safety-function in a unique manner since the methodology used to develop it (1) is based on a large body of historical data and (2) uses a relative approach of ensuring that nuclear plant systems will perform at least as well as systems that performed well in past earthquakes. (orig.)

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

The effect of Ti conduit on the critical current in (Nb,Ti)3Sn cable-in-conduit conductors  

International Nuclear Information System (INIS)

The effect of titanium conduit on the critical current in (Nb,Ti)3Sn 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. Titanium has equivalent thermal contraction coefficient to that of (Nb,Ti)3Sn filaments, and it is expected by using titanium as the conduit to suppress degradation of critical current due to excess thermal prestrain on (Nb,Ti)3Sn filaments. Some titanium conduit sample conductors were made, and thier critical current performance were measured together with some stainless steel (SUS316) and copper-nickel alloy (Cu-10Ni) conduit conductors. The experimental results indicated that the titanium conduit conductors had no critical current degradation due to thermal strain, whereas the stainless steel and copper-nickel alloy conduit conductors showed remarkable degradation on thier critical current performance and greater degradation was observed with smaller void conductor. In conclusion, titanium is verified to be excellent conduit material for (Nb,Ti)3Sn cable-in-conduit conductors. (author)

73

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

Science.gov (United States)

... Recordkeeping requirements concerning conduit financing arrangements. 1.881-4... Recordkeeping requirements concerning conduit financing arrangements. (a) Scope...whether that financing arrangement is a conduit financing arrangement. (2)...

2010-04-01

74

78 FR 63176 - Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting...  

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...robert.bell@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-10-23

75

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...christopher.chaney@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-11-21

76

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

Science.gov (United States)

...2010-04-01 true 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...

2010-04-01

77

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...christopher.chaney@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-11-19

78

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...robert.bell@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-08-30

79

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

Science.gov (United States)

...Preliminary Determination of A Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...robert.bell@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-10-08

80

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...robert.bell@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-10-09

 
 
 
 
81

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...christopher.chaney@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-10-09

82

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...robert.bell@ferc.gov. Qualifying Conduit Hydropower Facility Description:...

2013-10-16

83

Cardiac compression secondary to a massively dilated substernal colon conduit.  

Science.gov (United States)

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

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

2012-11-01

84

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)

85

Arterial conduits for hepatic artery revascularisation in adult liver transplantation.  

Science.gov (United States)

Arterial complications after orthotopic liver transplantation (OLT), including hepatic artery thrombosis (HAT), are important causes of early graft failure. The use of an arterial conduit is an accepted alternative to the utilisation of native recipient hepatic artery for specific indications. This study aims to determine the efficacy of arterial conduits and the outcome in OLT. We retrospectively reviewed 1,575 cadaveric adult OLTs and identified those in which an arterial conduit was used for hepatic revascularisation. Data on the primary disease, indication for using arterial conduit, type of vascular graft, operative technique and outcome were obtained. Thirty-six (2.3%) patients underwent OLT in which arterial conduits were used for hepatic artery (HA) revascularisation. Six of these were performed on the primary transplant, while the rest (n=30) were performed in patients undergoing re-transplantation, including six who had developed hepatic artery aneurysms. The incidence of arterial conduits was 0.4% (6/1,426 cases) in all primary OLTs and 20.1% (30/149 cases) in all re-transplants. Twenty-nine procedures utilised iliac artery grafts from the same donor as the liver, six used iliac artery grafts from a different donor, and a single patient underwent a polytetrafluoroethylene (PTFE) graft. Two techniques were used: infra-renal aorto-hepatic artery conduit and interposition between the donor and recipient native HAs, or branches of the HAs. The 30-day mortality rate for operations using an arterial conduit was 30.6%. Three conduits thrombosed at 9, 25 and 155 months, respectively, but one liver graft survived without re-transplantation. The arterial conduits had 1- and 5-year patency rates of 88.5% and 80.8%. The 1- and 5-year patient survival rates were 66.7% and 44%. We can thus conclude that an arterial conduit is a viable alternative option for hepatic revascularisation in both primary and re-transplantation. Despite a lower patency rate than that of native HA in the primary OLT group, the outcomes of arterial conduit patency and patient survival rates are both acceptable at 1 and 5 years, especially in the much larger re-OLT group. PMID:15107973

Muralidharan, Vijayaragavan; Imber, Charles; Leelaudomlipi, Surasak; Gunson, Bridget K; Buckels, John A C; Mirza, Darius F; Mayer, A David; Bramhall, Simon R

2004-05-01

86

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

International Nuclear Information System (INIS)

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

87

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...is making or managing investments...Standard for treatment as a conduit...applying the special rules for multiple...intermediate entity need not have...short-term funding needs, DS needs long-term...efficient way of managing their...

2010-04-01

88

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)

89

Articulated device for guiding a band of conduits  

International Nuclear Information System (INIS)

The device consists of a support comprising at least two articulated arms to form of a pair of compasses; when the compasses are closed, all the conduits have the same internal radius of curvature. Each arm comprises two bars connected by a holding structure between which the conduits are disposed. A bar of one arm is connected to a bar of the other arm by an articulated joint so that the two joints between the bars are on either side of the band of conduits during actuation of the arms. The device is useful for guiding electrical cables, fluid supply tubes, etc, in the core cover of a liquid metal cooled, fast neutron nuclear reactor. The device can maintain a large number of conduits without risk of tangling or rupture when the arms are closed

90

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

91

[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 < 0.01). The degradation rates of non-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 < 0.01). The average linearities in dry and hygrometric state of the nerve guide conduit were (0.597 +/- 0.012) LC and (0.333 +/- 0.015) LC, respectively, which also had statistical significance (P < 0.01). The flexibility in the hygrometric state of the nerve guide conduit was better than that of the dry. SEM analysis of the samples demonstrated that the structures of the nerve guide conduit were significantly changed in 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

92

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.)

93

The role of geodesist in building gas conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the research project are introduced all legal and tehnical aspects of planning, projecting, building and giving gas conduit in to use. It is explained and presented the register of economic public infrastructure, how to get an information of land where the future building will be, required documentation for building permit, how to mark out the future gas conduit, the way of surveying actual situation on the ground under construction. geodetic plan of the new situation is also introduced in...

Kovac?ic?, Andrej

2006-01-01

94

Pseudomembranous colitis associated with changes in an ileal conduit.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A case of antibiotic associated pseudomembranous colitis following total cystectomy is reported, in which there was involvement of the ileal conduit. The small bowel remaining in situ was uninvolved. Bacteriological studies revealed Clostridium difficile and the toxin in both colon and ileal conduit. Relevant publications concerning pathogenesis are discussed, in relation to the unusual site described in this case. Epidemiological evidence is reviewed which suggests that isolation of patients...

Shortland, J. R.; Spencer, R. C.; Williams, J. L.

1983-01-01

95

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

96

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

97

Prospective clinical study on digital nerve repair with collagen nerve conduits and review of literature.  

Science.gov (United States)

Little data are available concerning conduit repair of digital nerve lesions. We are presenting a prospective two-center cohort study on digital nerve reconstruction with collagen nerve conduits. The data are put into the context of a comprehensive review of existing literature. Over a period of 3 years, all consecutive digital nerve lesions that could not be repaired by tensionless coaptation with a gap length of less than 26?mm were reconstructed with nerve conduits made from bovine collagen I. Sensibility was assessed 1?week, 3, 6, and 12 months postoperatively by static and moving 2-point-discrimination (2PD) and monofilament testing. Forty-nine digital nerve lesions in 40 patients met the inclusion criteria. The mean nerve gap was 12.3 ± 2.3 mm (span 5-25 mm). Forty nerve reconstructions could be included in the 12-month follow-up. Three cases, assessed 12 months postoperatively, showed excellent sensibility (static 2PD?15?mm, but protective sensibility), and 9 achieved no sensibility. Monofilament test results were significantly better if gap length was shorter than 12 mm. Our results confirm tubulization as one possible technique in nerve reconstruction for gap lengths of 5 to 25 mm. PMID:24338485

Lohmeyer, Joern Andreas; Kern, Yasmin; Schmauss, Daniel; Paprottka, Felix; Stang, Felix; Siemers, Frank; Mailaender, Peter; Machens, Hans-Guenther

2014-05-01

98

Method and means for disposal of radioactive waste  

International Nuclear Information System (INIS)

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

99

Development of a scattering probability method for accurate vapor fraction measurements by neutron radiography. Revision 1  

International Nuclear Information System (INIS)

Recent test results indicated drawbacks associated with the simple exponential attenuation method (SEAM) as currently applied to neutron radiography measurements to determine vapor fractions in a hydrogenous two-phase flow in a metallic conduit. The scattering component of the neutron beam intensity exiting the flow system is not adequately accounted for by SEAM, and this leads to inaccurate results. To properly account for the scattering effect, a neutron scattering probability method (SPM) is developed. The method applies a neutron-hydrogen scattering kernel to scattered thermal neutrons that leave the incident beam in narrow conduits but eventually show up elsewhere in the measurements. The SPM has been tested with known vapor (void) distributions within an acrylic disk and a water/vapor channel. The vapor (void) fractions deduced by SPM are in good agreement with the known exact values. Details of the scattering correction method and the test results are discussed

100

Technical Issues in the Use of the Radial Artery as a Coronary Artery Bypass Conduit.  

Science.gov (United States)

The clinical and angiographic benefits related to the use of the radial artery (RA) as a bypass conduit have extensively been proven. However, due to its morpho-functional features and its anatomic position, successful use of the RA requires careful consideration of several technical issues. We herein summarize the current evidence on all the technical aspects related to the RA use in coronary surgery such as the preoperative evaluation of ulnar compensation, the different means of intraoperative vasodilatation, and the various harvesting techniques. PMID:25443025

Gaudino, Mario; Crea, Filippo; Cammertoni, Federico; Mazza, Andrea; Toesca, Amelia; Massetti, Massimo

2014-12-01

 
 
 
 
101

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

102

Single-friction-surface triboelectric generator with human body conduit  

International Nuclear Information System (INIS)

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

103

Modeling Reactive Transport in Coupled Groundwater-Conduit Systems  

Science.gov (United States)

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

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

2002-05-01

104

Sciatic nerve repair using adhesive bonding and a modified conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

When repairing nerves with adhesives, most researchers place glue directly on the nerve stumps, but this method does not fix the nerve ends well and allows glue to easily invade the nerve ends. In this study, we established a rat model of completely transected sciatic nerve injury and repaired it using a modified 1 cm-length conduit with inner diameter of 1.5 mm. Each end of the cylindrical conduit contains a short linear channel, while the enclosed central tube protects the nerve ends well. ...

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

2014-01-01

105

Passive Vaporizing Heat Sink  

Science.gov (United States)

A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

2011-01-01

106

[Myocardial revascularization with arterial conduits: comparison of bilateral internal mammary artery and single internal mammary artery].  

Science.gov (United States)

The use of bilateral internal mammary artery (BIMA) grafting for myocardial revascularization has been demonstrated to provide long-term benefits compared to revascularization using single left internal mammary artery (SIMA) and venous conduits. However, it is still controversial whether the use of BIMA is associated with a higher hospital mortality and morbidity. The present study retrospectively evaluated the possible advantages related to the use of BIMA at 3-year follow-up and whether the presence of operative risk factors in patients with BIMA could limit the application of the procedure in myocardial revascularization. We compared two groups of 100 patients matched for preoperative clinical characteristics, who underwent myocardial revascularization on the left coronary system with BIMA (93 males and 7 females, mean age 59 +/- 4 years) or with SIMA and venous conduits (86 males and 14 females, mean age 63 +/- 6 years). Hospital mortality rate was 2% in both groups, the use of BIMA being not a significant risk factor for hospital mortality and morbidity. The mean follow-up was 36 +/- 6 months for the BIMA group and 40 +/- 10 months for the SIMA group. At 3 years, there was no significant differences in the actuarial freedom from cardiac death (96 +/- 2% for BIMA vs 94 +/- 2% for SIMA patients), myocardial infarction (98 +/- 2 vs 97 +/- 2%), angina (93 +/- 2 vs 91 +/- 2%), symptomatic heart failure (92 +/- 3 vs 92 +/- 2%), coronary angioplasty/reoperation (96 +/- 2 vs 97 +/- 2% ), and total cardiac events (80 +/- 4 vs 76 +/- 4%). BIMA grafting was not an independent predictor of late cardiac events. In 66 patients who underwent a late angiographic or echo-Doppler study, the patency rate was 100% for the left mammary artery, 94% for the right mammary artery and 69% for venous conduits. In conclusion, myocardial revascularization with BIMA in situ is associated with low hospital mortality and morbidity, good clinical outcome and excellent patency rate at 3 years, with apparently no significant differences when compared to the use of SIMA and venous conduits. The low hospital mortality and morbidity and the satisfactory medium-term results in our opinion justify a more extensive use of BIMA in myocardial revascularization. PMID:10208053

Codecasa, R; Milano, A; De Carlo, M; Levantino, M; Tartarini, G; Nardi, C; Magagnini, E; Bortolotti, U

1999-02-01

107

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

108

Geologic Constraints on Conduit Formation at Explosive Basaltic Volcanoes  

Science.gov (United States)

Models of explosive basaltic processes often are sensitive to shallow (Tolbachik, Kamchatka, violent strombolian basalt eruption are derived from Quaternary volcanic (0-1 km deep) and Tertiary sedimentary (1-4 km) rocks. Xenolith abundances in the lower half of fall deposits from the Cone 1 eruption stage are 0.001-0.01 vol%. This period sustained 6-10-km high eruption columns and lacked lavas. Xenolith abundances increase to 0.01-1.0 vol% in the upper half of the deposits, which correlates with lava effusion and columns 2-6-km high. The 3x105 m3 total xenolith volume represents a cylindrical conduit 15+/-2 m in diameter and 1.7+/-0.2 km deep. Eruption of Cone 1 ended with 12 hr of hydromagmatic falls containing 3x106 m3 (70 vol%) xenoliths. The conduit must have widened from 15+/-2 to 48+/-4 m to produce this xenolith volume. The subsequent Cone 2-3 eruption stage produced abundant lavas and eruption columns <4-km high. Xenolith abundances are 0.01-0.1 vol%, indicating progressive widening of the conduit to 6+/-1 m extending to 2.8+/-0.4 km depth. Simultaneous eruptions of tephra and lava suggest an annulus of degassed magma developed on conduit walls, enhancing xenolith entrainment; little entrainment occurred early at Cone 1 with an apparent droplet flow regime. Alkali basalt plugs and dikes representing 1+/-0.5 km paleodepths are exposed in the 4 Ma San Rafael volcanic field, Utah. Dike-plug complexes represent typical dimensions for basaltic volcanic eruptions and are interpreted as subvolcanic conduit systems. Mapped conduits range from 2-m wide buds along dikes with little wall-rock disruption, to 10-60-m wide cylindrical plugs having <5-m wide conduit margins with abundant xenoliths. These margins may represent typical wall-rock plucking and conduit widening during annular flow (i.e., late Cone 1 and Cone 2-3). Several larger conduits, however, have a 1-6 m xenolith-poor annulus with a 10-40 m inner core of extensive wall-rock breccia and pervasive low-temperature hydrothermal alteration. Xenoliths in the inner breccia often are derived from deeper stratigraphic units. These brecciated conduits appear analogous to late-stage hydromagmatic events at Cone 1. Models of explosive basaltic cinder cone eruptions should consider that subvolcanic conduit diameters to <2 km depth may progressively widen to order of 10-60 m. Work supported by U.S. Nuclear Regulatory Commission (Contract NRC-02-97-009) and is an independent product of CNWRA that does not necessarily reflect NRC views or regulatory positions.

Hill, B. E.; Doubik, P.; Connor, C. B.

2001-12-01

109

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

110

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

Science.gov (United States)

... Allocation of expenses by real estate mortgage investment conduits. 1.67-3 Section 1.67-3 Internal Revenue ...Allocation of expenses by real estate mortgage investment conduits. (a) Allocation of allocable investment expenses....

2010-04-01

111

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

112

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...gov. [[Page 68053

2013-11-13

113

Metal vapor laser having cataphoresis means  

Energy Technology Data Exchange (ETDEWEB)

A radiation emission device characterized by a cylindrical cathode enclosed by an elongated envelope having a body section and two end sections is disclosed. The device includes an anode terminal, coupled to the body section, which serves to provide electrical energy to excite metallic material inside the envelope. The device further includes a pair of cataphoresis terminals located along each end section to prevent the excited metallic material from drifting into contact with radiation transmission windows located at the terminus of each end section.

Wang, S.C.; Hamerdinger, R.W.; Hug, W.F.

1977-10-04

114

Aorto-conduit fistula developing four years after esophagectomy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

115

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...liability on a withholding agent who fails to withhold as required under § 1.1441-3(j), but not for purposes of § 1.882-5. (B) Character of payments made by the financed entity. If the participation of a conduit financing...

2010-04-01

116

Evaluation of the MODFLOW-2005 Conduit Flow Process.  

Science.gov (United States)

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

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

2010-01-01

117

Influence of spontaneously occurring bursts of muscle sympathetic nerve activity on conduit artery diameter  

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Large increases in muscle sympathetic nerve activity (MSNA) can decrease the diameter of a conduit artery even in the presence of elevated blood pressure, suggesting that MSNA acts to regulate conduit artery tone. Whether this influence can be extrapolated to spontaneously occurring MSNA bursts has not been examined. Therefore, we tested the hypothesis that MSNA bursts decrease conduit artery diameter on a beat-by-beat basis during rest. Conduit artery responses were assessed in the brachial ...

Fairfax, Seth T.; Padilla, Jaume; Vianna, Lauro C.; Holwerda, Seth H.; Davis, Michael J.; Fadel, Paul J.

2013-01-01

118

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

119

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

Science.gov (United States)

...Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments...notice of intent to construct a qualifying conduit hydropower facility, pursuant to section...HREA). The Nelson Street 17 kW In-Conduit Hydroelectric Net-Metered Project...

2013-09-16

120

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)

 
 
 
 
122

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

123

Vaporization of perfluorocarbon droplets using optical irradiation  

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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

124

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(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

125

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 utvements 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

126

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

International Nuclear Information System (INIS)

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

127

Studies on forced convection nanofluid flow in circular conduits  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental system was developed and used to study the nanofluid flow and heat transfer in circular conduits. Experiments were performed for a variety of nanofluid flow features in the system. Results obtained from the study show that the heat transfer rate for flow of the base fluid is less than that of the nanofluid used in the study. It was also found that the observed relationship between molecular diffusivity of momentum and the molecular diffusivity of thermal energy at the macroscale may not necessarily be the same at the nanoscale. A heat transfer correlation for turbulent forced convection flow in circular pipes was developed from the results in terms of Nusselt number, Reynolds number and Prandtl number. The correlation developed was compared to related correlations in the literature. Important factors that affect nanofluid flow and heat transfer in circular conduits were also determined. This type of study is essential for heat exchanger applications.

Harikrishna Vishwanadula

2012-03-01

128

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

129

Single-friction-surface triboelectric generator with human body conduit  

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-03-10

130

Coarsening of capillary drops coupled by conduit networks  

Science.gov (United States)

A system of n spherical-cap drops, coupled by a network of conduits, coarsens due to surface tension forces. The total interfacial energy drives the fluid through the conduits such that, with time, the volume becomes increasingly localized into fewer large drops. The coarsening rate is predicted heuristically for drops coupled by orthogonal networks, a porous medium, and fractal networks of various dimensions. The predicted coarsening law as it depends upon the type and dimension of network, total number of drops, and initial drop volume is compared against numerical simulations of large n . Additionally, distributions of large drop volumes are obtained using a Lifshitz-Slyozov-Wagner (LSW) model. The predicted distributions are independent of network topology; in contrast, simulation results depend weakly on the network dimension. The heuristic coarsening rate laws are recovered using the LSW model for all but a square network topology.

van Lengerich, Henrik B.; Vogel, Michael J.; Steen, Paul H.

2010-12-01

131

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

132

Studies on forced convection nanofluid flow in circular conduits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Harikrishna Vishwanadula; Nsofor, Emmanuel C.

2012-01-01

133

Interactions of large amplitude solitary waves in viscous fluid conduits  

Science.gov (United States)

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, but a theoretical and experimental classification of strongly nonlinear solitary wave interactions is lacking. The interactions of large amplitude solitary waves in viscous fluid conduits, a model physical system for the study of one-dimensional, truly dissipationless, dispersive nonlinear waves, are classified. Using a combined numerical and experimental approach, three classes of nonlinear interaction behavior are identified: 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 behave as "physical solitons." Experimental data are shown to be in excellent agreement with numerical simulations of the reduced model. Experimental movies are available with the online version of the paper.

Lowman, Nicholas K.; Hoefer, M. A.; El, G. A.

2014-07-01

134

Free-boundary models of a meltwater conduit  

Science.gov (United States)

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

Dallaston, Michael C.; Hewitt, Ian J.

2014-08-01

135

Integration of large-scale experiments and numerical simulations for the calibration of friction laws in volcanic conduit flows  

Science.gov (United States)

The eruptive columns of explosive volcanism are fed by a gas-particle conduit flow, which characteristics determine the eruptive regime and are important for assessing the hazard of active volcanoes. In this paper, by means of the combined use of large-scale experiments and numerical modeling, a study on some parameters of the gas-particle conduit flow of explosive eruptions is carried out. A 1D two-phase non-homogeneous Eulerian-Eulerian model has been developed for checking the influence of some crucial quantities: interphase drag, particle-wall friction and particle shape factor. Hundreds of different parameters combinations are tested and used for the simulation of controlled experimental runs. The parameter combination that best fits the whole set of experiments, including both column collapses and convective plumes, results into an average error of about 10%. A further analysis has been carried out to determine the sensitivity of solutions to model parameters. The choice of the interphase drag does not influence dramatically the solution, except for highly concentrated flows. The particle shape factor severely affects gas and particle velocities. The influence of various particle-wall friction laws, which were originally obtained in pneumatic engineering, is thoroughly investigated, as the suitability of these laws has never been proved in volcanology. A detailed parametric analysis allowed the re-calibration of two of these laws, which are now specifically tailored for the case of highly concentrated conduit flows that feed collapsing columns, and dilute flows that feed convective plumes.

Dioguardi, F.; Dellino, P.; de Lorenzo, S.

2013-01-01

136

Chemical vapor infiltration using microwave energy  

Science.gov (United States)

A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

Devlin, David J. (Los Alamos, NM); Currier, Robert P. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Barbero, Robert S. (Santa Cruz, NM)

1993-01-01

137

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

International Nuclear Information System (INIS)

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

138

Imaging of platelets in right-sided extracardiac conduits in humans  

International Nuclear Information System (INIS)

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

139

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

White, W. B.; White, E. L.

2005-01-01

140

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 k...

Reimann, T.; Giese, M.; Geyer, T.; Liedl, R.; Mare?chal, J. C.; Shoemaker, W. B.

2013-01-01

 
 
 
 
141

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

142

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...

Meduoye Ayo; Ferreira Ignacio; Galiñanes Manuel; Sosnowski Andrzej

2011-01-01

143

Evaluation of the ITER cable in conduit conductor heat transfer  

International Nuclear Information System (INIS)

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

144

Migrating quake swarm may indicate magma conduit clog  

Science.gov (United States)

On 13 January 2006, Augustine Volcano, a towering volcano offshore from the Alaska Peninsula, erupted explosively. In the days leading up to the eruption, a series of explosions and earthquake swarms had warned of the impending activity. On 12 January, 36 hours before the first magmatic explosions, a swarm of 54 earthquakes was detected across the 13-station seismic network on Augustine Island. Analyzing the seismic waves produced by the earthquakes, Buurman and West found that the earthquakes were being triggered from point sources within the magma conduit itself.

Schultz, Colin

2014-03-01

145

Modelling the transition to slug flow in horizontal conduit  

International Nuclear Information System (INIS)

A physical model for the prediction of transition to slug flow is presented. The model assumes that the slug is formed as a result of a hydraulic jump which is sufficient to just touch the top wall of the conduit. This, together with 'a breaking dam' assumption at the rear of the slug, gives necessary and sufficient conditions for the formation of a stable slug. The minimum liquid film thickness ahead of the slug, degree of aeration within the slug and slug translational velocity are predicted. The predictions agree very well with those of previous workers and with experimental data

146

Hydraulic and geological factors influencing conduit flow depth  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Worthington, S. R. H.

2005-01-01

147

Heating-induced flows in cable-in-conduit conductors  

International Nuclear Information System (INIS)

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

148

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

Science.gov (United States)

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

149

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

150

Development of a new lacrimal drainage conduit using POSS nanocomposite.  

Science.gov (United States)

Lacrimal surgery in cases of severely obstructed or missing canalicular ducts is highly challenging. In these cases, the placement of a bypass tube is currently the only option to restore the drainage of tears into the nose and reduce the symptomatic watery eye. Different approaches to achieve functional drainage have been tried using blood vessels or artificial implants. The implantation of the rigid Lester Jones tube is, since its introduction in the late 1960s, the gold standard. The functional success is satisfactory. However, complication rates are high and remain, even with many modifications of the original design, a major problem. These complications include mainly the displacement and blockage of the tube, requiring regular checkups, as well as irritation of the surrounding tissue including the nose and the eye. The objective of this study was to develop a new lacrimal duct conduit (LDC) to restore structural and functional integrity of the lacrimal drainage system. The conduit is constructed with a novel polymer, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU), that offers biocompatibility. We exploit nanotopography to evade the problems associated with current applications. A number of extrusion techniques were investigated for this purpose: ultrasonic atomization spraying, electrohydrodynamic atomization spraying/spinning, extrusion-coagulation, and high-pressure coagulation by autoclave and casting. Finally, the coagulation and cast technique were selected to construct an LDC superior to its predecessors, and its advantages highlighted. PMID:21995539

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

2011-01-01

151

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

152

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

153

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

154

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. PMID:23914260

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

2013-01-01

155

Hydraulic transients in pumping station-main conduit - Cooling tower systems  

International Nuclear Information System (INIS)

The paper presented a method of starting up a pump with a partially filled main conduit allows to avoided filling the conduit with a low head and draining the pipeline followed by rotation of the pump in the opposite direction. This provides reduction of dynamic loads on the system elements and increases the reliability and time of the work

156

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

157

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Naouar Laaidi; Sougrati Belattar

2013-01-01

158

An integrated model of magma chamber, conduit and column for the analysis of sustained explosive eruptions  

Science.gov (United States)

Explosive volcanic eruptions comprise a complex series of processes involving withdrawal from the magma chamber, magma ascent along the conduit and eruption column dynamics. Numerous studies have modeled the different sub-domains of a volcanic system, but their interplay has seldom been analyzed. To this end, we developed C3 (C-cubed, that stands for Chamber, Conduit and Column), a new integrated model that describes the dynamics of an explosive eruption as a series of steady state regimes and as a function of geometry and initial conditions of the magma reservoir. We used Global Sensitivity Analysis to quantify the role of the relevant model parameters and describe the interplay between the different volcanic sub-domains. In particular, we analyzed the evolution of a sustained explosive eruption in order to identify the conditions for buoyant, super-buoyant and collapsing columns. Input data were based on field reconstructions of Quaternary explosive eruptions in the Vulsini Volcanic District (Roman Province, central Italy). Model results show that: 1) the column regime, although affected by complex interactions among several factors, mostly depends on the conduit radius, the volatile content (i.e. supersaturation concentration at the top of the chamber) and length of the conduit, in decreasing level of importance; 2) the amount of mass erupted is independent of the conduit radius and depends mostly on volatile supersaturation, the radius of the magma chamber, the length of the conduit and the overpressure at the conduit inlet; 3) the mass flow-rate, column height and duration of the eruption are largely controlled by the conduit radius; 4) the flow pressure and density at the conduit exit are mostly controlled by the conduit inlet overpressure at the onset of the eruption, and by the length of the conduit at the end of the eruption; 5) the exit velocity from the conduit is mostly controlled by the volatile content, the length of the conduit and the inlet overpressure. In this model framework, and with specific reference to selected Plinian events of the Vulsini Volcanic District, simulation results show that column collapse is not achieved for reasonable eruption durations (order of hours) and conduit widths (tens of meters). This is consistent with field reconstructions suggesting that column collapse did not likely occur and that pyroclastic flows were therefore generated by independent mechanisms from ring fissures and/or multiple vents concomitant to caldera collapse.

Colucci, S.; de'Michieli Vitturi, M.; Neri, A.; Palladino, D. M.

2014-10-01

159

Effect of the conduit material on CICC performance under high cycling loads  

Energy Technology Data Exchange (ETDEWEB)

Recent ITER Model Coils and CRPP tests on Nb3Sn Cable in Conduit Conductors (CICC) showed a significant and unexpected increase in the broadness of the transition to the normal state, resulting in degradation of superconducting properties. To investigate these phenomena two CICC samples were built with identical 144 strand cables but different conduit materials. One sample had titanium conduit with low coefficient of thermal expansion (CTE), the other had stainless steel conduit. The purpose of this experiment was to study changes in strand properties in the cable (n-value, I{sub c}, T{sub cs}), the effect of cycling and high electromagnetic load and the effect of the conduit on the CICC performance.

Martovetsky, N N; Bruzzone, P; Stepanov, B; Wesche, R; Gung, C; Minervini, J V; Takayasu, M; Goodrich, L F; Ekin, J W; Nijhuis, A

2004-09-01

160

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

 
 
 
 
161

Method and apparatus for reducing drag and noise associated with fluid flow in a conduit  

Science.gov (United States)

A method and apparatus for reducing drag and noise associated with fluid flow within a conduit is provided. The conduit has flexible walls that are shaped to form stationary waves having peaks and troughs and are repeated in the axial direction of the conduit. The stationary waves are moved along the axial direction of the conduit whereby a vortex is trapped in the fluid flow at each of the troughs. Each of the vortices forms part of an isolating layer between the conduit wall and the main stream of the fluid flow thereby reducing drag. Furthermore, the vortices push the dominant noise producing region toward the center of the fluid flow where sound coupling efficiency is lower.

Ng, Kam W.

1991-07-01

162

Hot upwelling conduit beneath the Atlas Mountains, Morocco  

Science.gov (United States)

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

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

2014-11-01

163

Cable-in-conduit conductor optimization for fusion magnet applications  

International Nuclear Information System (INIS)

Careful design of the toroidal-field (TF) and poloidal-field (PF) coils in a tokamak machine using cable-in-conduit conductors (CICC) can result in quite high overall winding-pack current densities - even with the high nuclear heat loads that may be imposed in operating a fusion reactor - and thereby help reduce the overall machine size. In our design process, we systematically examined the operational environment of a magnet, e.g., mechanical stresses, current, field, heat load, coolant temperature, and cooldown stresses, to determine the optimum amounts of copper, superconductor, helium, and sheath material for the CICC. This process is being used to design the superconducting magnet systems that comprise the Tokamak Ignition/Burn Experimental Reactor (TIBER II). 13 refs., 2 figs

164

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

165

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

166

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.

167

Fluid-Rock Dynamic Interaction in Magmatic Conduits: Modelling Transients Using an Analytical Solution  

Science.gov (United States)

We compute transients fluid-rock dynamic interaction in a fluid driven axisymmetric conduit embedded in an infinite, homogeneous elastic space. Both fluid and solid are dynamically coupled fulfilling continuity of velocities and radial stresses at the conduit's wall. The calculation model considers the viscosity as a key parameter leading to non-linear scheme. A pressure transient at a point of the conduit, that perturbs a steady flow of incompressible viscous fluid, produces the interaction between the fluid and motion at the conduit's walls. The fluid motion induces the elastic response of the conduit forcing it to oscillate radially. The fluid-filled conduit dynamics is governed by three second-order, ordinary non-linear differential equations, which are solved numerically by applying a fifth-order Runge-Kutta scheme. Boundary conditions satisfy the Bernoulli's principle allowing coupling several pipe segments which may present smooth variation in fluid properties. The nature of the source involves different pressure excitations functions including those measuring during simulations of gas burst and fragmentation of volcanic rocks under controlled laboratory conditions. Far-field velocity synthetics radiated by motion of the conduit's walls and fluid flows ascending to the surface, display characteristic waveforms and frequency content that are similar to those of long-period signals and tremor observed at active volcanoes. Results suggest that transient fluid flow induced oscillations may explain long-period and tremor signals. Advantages and limitations of this approach are discussed.

Arciniega-Ceballos, Alejandra; Scheu, Bettina; Sanchez-Sesma, Francisco; Dingwell, Donald

2014-05-01

168

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

Science.gov (United States)

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

Quareni, Francesca; Mulargia, Francesco

1993-03-01

169

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

170

Amélioration de l'agrément de conduite via le pilotage du groupe motopropulseur  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La transmission à double embrayage a été introduite dans les véhicules afin d'améliorer le confort de conduit, l'économie de conduite et de diminuer le temps de changement de vitesses. La gestion du double embrayage joue un rôle important sur le confort de conduite. L'objectif principal de ce travail concerne alors la synthèse des lois de commande du double embrayage en phase de décollage et lors du changement de vitesses. Le mémoire est structuré de la façon suivante : le premier...

Tran, Nhu

2013-01-01

171

Diversity Of Clast Types And Their Implications For Conduit Processes  

Science.gov (United States)

Small volume, sub-plinian andesite eruptions produce a range of clasts which can be either texturally diverse but compositionally similar or vice versa. Each clast type records the particular mechanism by which it was generated and can involve either purely geochemical or physical processes or interacting physico-chemical mechanisms. To understand the genesis of clast types we investigated the texture, mineral and bulk chemical composition, as well as melt inclusion studies, from clasts in deposits of the last sub-plinian eruption of Mt. Taranaki, New Zealand. These results are used, along with data obtained from studies of other lava dome- forming eruptions, to explore processes in the shallow crustal magma storage region and the changes the magma experiences once it leaves that region. Further, shallow, intra-edifice conduit processes are identified that explain the diversity in clast types. Five basic rock types were produced during the AD 1655 Burrell Lapilli eruption of Mt. Taranaki: dense grey andesite clasts with a range in bulk composition from 57.1 to 59.5 wt. % SiO2, and four pumice types grey, brown, black and grey-brown banded clasts which are similar in bulk composition to the andesite clasts with SiO2 between 55.5-56.0 wt. %. However, the pumice types are fundamentally different in terms of vesicularity and somewhat different glass chemistry. Bulk vesicularities are highest for brown pumice with a median of 70.7 %, followed by grey pumice with 68.5 %, banded pumice with 63.8 %, and then black pumice with 49.9 %. Moreover, the permeability of the Burrell Lapilli samples is generally up to 10 times higher at given porosities (e.g. 5.3x10-11m2 at bulk vesicularity of 75.1 %) compared to literature data for dacitic and rhyolitic pumice compositions. The development of different coloured pumice types is the result of slightly differing physical magma properties (e.g. temperature, viscosity, volatile content) resulting in changes in vesicle texture and glass composition. This is directly controlled by syn-eruptive decompression and fragmentation processes rather than pre-eruptive magma evolution. These processes occur within an stratified upper conduit (including lateral variations in magma properties) and explain the generation of different pumice types and is consistent with field observations of a succession of three pyroclastic flows deposits of grey, brown and grey pumice. These three units represent eruption pulses and correspond to three levels of bubble nucleation at different growth rates. The brown pumice formation represents slower volatile exsolution and bubble growth with subsequent microlite crystallisation. This pre- mature bubble network caused slower fragmentation rates, and hence, pulsation during fragmentation.

Platz, T.; Cronin, S. J.; Cashman, K. V.; Stewart, R. B.

2006-12-01

172

A conduit dilation model of methane venting from lake sediments  

Science.gov (United States)

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

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

2011-01-01

173

[Experience with the use of autoarterial conduits in coronary surgery].  

Science.gov (United States)

Between September 1999 and until the present time 14 direct myocardial revascularization using arterial conduits were performed at the Department of Vascular Surgery and Surgical Treatment of CAD, V. Vakhidov Scientific Center of Surgery, RU Ministry of Public Health. The internal mammary artery was used in all the cases, right gastroomental artery in 2 cases. Revascularization of one coronary artery was accomplished in 2 patients, of two arteries in 8 and of three coronary arteries in 4 patients. In 12 cases, direct myocardial revascularization was realized on the working heart and in 2 cases, under cardiopulmonary bypass. Ischemic changes on the ECG at rest, recorded in the preoperative period, disappeared following operation. In all the patients, myocardial contractility (EF) after operation rose by 6-8% on an average as compared to the initial level. Physical exercise tolerance was measured by BEM in 6 (42.9%) patients. Angina of effort, FC II, was diagnosed only in 2 patients. All the patients were discharged in a satisfactory condition. Only patients with unstable angina were recommended to take long-acting nitrates whereas the remaining subjects were advised to take the antiaggregation doses of aspirin. PMID:15163997

Bakhritdinov, F Sh; Kamilov, Sh M; Trynkin, A V; Babadzhanov, S A

2004-01-01

174

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

175

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

176

CFD modeling of ITER cable-in-conduit superconductors  

International Nuclear Information System (INIS)

In the first paper of this series, we proposed a novel approach to help understand some of the complex processes occurring in dual-channel cable-in-conduit conductors (CICC) as used in the superconducting coils of the international thermonuclear experimental reactor (ITER): the constitutive relations including transport coefficients needed in input by standard global 1D tools for the analysis of thermal-hydraulic transients in ITER coils, e.g., the Mithrandir/M and M code, are derived from local 3D analysis. A first validation of the model was performed showing very good agreement with available experimental data from different applications. The same advanced computational fluid dynamics (CFD) tool, the FLUENT code, including sophisticated turbulence models, is used here to compute the pressure drop corresponding to an imposed mass flow rate in several geometries relevant for the central channel of the ITER CICC. The validation is extended to include more ITER-relevant conditions showing good accuracy with error bars on the friction factor ?±15%. We then apply the validated model to the study of the expected dependencies of the pressure drop in the central channel of an ITER CICC on the size of the gap and on the diameter of the delimiting spiral

177

A conduit dilation model of methane venting from lake sediments  

Science.gov (United States)

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

Scandella, Benjamin P.; Varadharajan, Charuleka; Hemond, Harold F.; Ruppel, Carolyn; Juanes, Ruben

2011-03-01

178

Injunctions against mere conduit of information protected by copyright  

DEFF Research Database (Denmark)

This paper includes an in-depth analysis of EU law and Scandinavian law on injunctions against internet access providers (IAPs) performing as mere conduit of information protected by copyright. In recent Scandinavian case law, courts have granted preliminary injunctions which have caused IAPs to either shut down specific internet connections allegedly used to infringe copyright or to block access to internet content, which allegedly infringed applicable copyright rules. This paper considers some significant legal challenges, which are emerging in the wake of this case law, and which should attract attention in all European member states. Firstly, it is shown that rules on preliminary injunctions are generally unable to safeguard the significant legitimate interests of third parties, which may be harmed by such relief, and that a proper implementation of Art. 8(3) of the Infosoc Directive requires rules, which take into due consideration the special aspects related to enforcement of copyright on the internet through IAPs. Secondly, it is shown that the termination of internet connections and the blocking of access to internet content may not support the public policies behind copyright law and also may restrict the freedom of expression under European human rights law. The analysis is based on a brief account for the relevant EU Directives, the implementation of these Directives in the Scandinavian countries and the Scandinavian case law regarding use of injunctions against IAPs to enforce copyright on the internet.

Sandfeld Jakobsen, SØren; Petersen, Clement Salung

2011-01-01

179

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

180

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

Science.gov (United States)

Our previous studies have histomorphologically confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit can be used to repair 30-mm-long sciatic nerve defects. However, the repair effects on rat behaviors remain poorly understood. In this study, we used nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous sciatic nerve to bridge 30-mm-long rat sciatic nerve gaps. Within 4 months after surgery, rat sciatic nerve functional recovery was evaluated per month by behavioral analyses, including toe out angle, toe spread analysis, walking track analysis, extensor postural thrust, swimming test, open-field analysis and nociceptive function. Results showed that rat sciatic nerve functional recovery was similar after nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous nerve grafting. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit is suitable in use for repair of long-segment sciatic nerve defects. PMID:25206560

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

2013-01-01

 
 
 
 
181

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

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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

182

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

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

Pimpun Tongpun

2014-08-01

183

Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP  

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Full Text Available Abstract Directional drilling at Unzen Volcano in Japan duringmid of 2004 penetrated the magma conduit and successfullyrecovered samples of the lava dike that is believed to havefed the 1991–1995 eruption. The dike was sampled about1.3 km below the volcano’s summit vent and is intrudedinto a broader conduit zone that is 0.5 km wide. This zoneconsists of multiple older lava dikes and pyroclastic veinsand has cooled to less than 200?C. The lava dike sample wasunexpectedly altered, suggesting that circulation of hydrothermalfluids rapidly cools the conduit region of even veryactive volcanoes. It is likely that seismic signals monitoredprior to emergence of the lava dome reflected fracturing ofthe country rocks, caused by veining as volatiles escapedpredominantly upward, not outward, from the rising magma.Geophysical and geological investigation of cuttings andcore samples from the conduit and of bore-hole logging datacontinues.

Kozo Uto

2005-09-01

184

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

185

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

International Nuclear Information System (INIS)

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

186

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

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OBJECTIVES To revise indications, case fatality ratio, and postoperative early and late complications of ileal conduit as a method of urinary diversion. METHODS 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, peroperative findings, and postoperative follow-up data were r...

Abol-enein, Hassan A.; Abdul-muhsin, Ausama S.; Alhallaq, Yousuf M.

2008-01-01

187

Simulations numériques de la multidiffusion acoustique en conduit, comparaison avec des modèles analytiques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nous nous intéressons à la caractérisation des effets de multi-diffusion dans les guides d'ondes. Nous considérons la propagation acoustique en régime harmonique dans un conduit horizontal 2D à parois rigides. Nous avons développé une approche numérique pour déterminer les propriétés effectives d'un milieu hétérogène aléatoire dans un conduit. A l'aide de simulations directes nous déterminons un champ cohérent en faisant la moyenne des champs sur de nombreuses réalisations ...

Lune?ville, Eric; Mercier, Jean-franc?ois

2010-01-01

188

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

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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

189

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

190

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a novel modelling approach to study the evolution of conduit networks in soluble rocks. Unlike the models presented so far, the model allows a transition from pressurised (pipe) flow to a free surface (open channel) flow in evolving discrete conduit networks. It calculates flow, solute transport and dissolutional enlargement within each time step and steps through time until a stable flow pattern establishes. The flow in each ti...

Perne, M.; Covington, M. D.; Gabrovs?ek, F.

2014-01-01

191

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

192

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Introduction & Objective: Peripheral nerve injury is common in trauma patients and 4.5% of all soft-tissue injuries are accompanied by defects of peripheral nerve. Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Designed conduits com-prised of natural and synthetic materials are now widely used in the construction of damaged tissues. The aim of this project was to prepare nanocomposite conduits from gelatin and bioglass for damaged peripheral nerve...

Foroutan Koudehi, M.; Ghanezadeh, F.; Amiri, A.; Imani Fooladi, A. A.; Nourani, M. R.

2014-01-01

193

Fontan operation for patients with complex anatomy: the intra-atrial conduit technique.  

Science.gov (United States)

The extracardiac conduit type of total cavopulmonary connection (TCPC) is the most common variation of the modified Fontan operation in current use. For patients with some forms of complex anatomy (eg, dextrocardia in situs solitus or asplenia syndrome), we have adopted a different technique: interposition of an intra-atrial conduit between the inferior vena cava (IVC) and the superior vena cava-right pulmonary artery (SVC-RPA) connection. We report our experience with six patients. PMID:23804784

Iacona, Gabriele M; Giamberti, Alessandro; Abella, Raul F; Muñoz, Julio Agredo; Mendieta, Saul Garcia; Pomé, Giuseppe; Frigiola, Alessandro

2012-04-01

194

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

Science.gov (United States)

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

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

2014-11-01

195

Functional recovery guided by an electrospun silk fibroin conduit after sciatic nerve injury in rats.  

Science.gov (United States)

The aim of this study was to evaluate the regenerative capacity of a newly developed nerve guidance conduit using electrospun silk fibroin (SFNC) implanted in a 10-mm defect of the sciatic nerve in rats. After evaluating the physical properties and cytocompatibility of SFNC in vitro, rats were randomly allocated into three groups: defect only, autograft and SFNC. To compare motor function and abnormal sensation among groups, ankle stance angle (ASA) and severity of autotomy were observed for 10?weeks after injury. Immunostaining with axonal neurofilament (NF) and myelin basic protein (MBP) antibodies were performed to investigate regenerated nerve fibres inside SFNC. ASA increased significantly in the SFNC group at 1, 7 and 10?weeks after injury compared to the defect only group (p?mean ASA of the SFNC group was significantly higher than that of the autograft group (p?

Park, Sook Young; Ki, Chang Seok; Park, Young Hwan; Lee, Kwang Gill; Kang, Seok Woo; Kweon, Hae Yong; Kim, Hyun Jeong

2015-01-01

196

Laboratory evaluation of Electromagnetic Pulse (EMP) hardness testing concepts for electrical conduit systems  

Science.gov (United States)

Four concepts were evaluated for potential use in testing the electromagnetic shielding integrity of metal conduits: the Hall effect, standing wave coupling, microwave resonant cavity, and diffusion current-leakage current comparison. Existing technology for hardness verification and defect location was reviewed for comparison with the new methods. Because of the phenomena involved, the four concepts are mainly for use with nonburied conduits. In addition, each method has its prospective application limited by one or more drawbacks to implementation: Hall effect devices require direct access to the conduit system and are subject to geometry-dependent variables; with standing wave coupling tests, it may be difficult to maintain a transmission line configuration for the conduit system; the microwave resonant cavity method also requires direct access to the conduit and its greatest potential is for testing of specific conduit components; low frequency phase comparison only verifies hardness, so defects must be located by another test. None of the new methods can be recommended without further development and field evaluation.

Nielsen, P. H.

1984-08-01

197

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

198

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

199

Discharge behaviour of the Blautopf spring and Gallusquelle spring (Swabian Alb / Germany) - relative importance of the fissured matrix and the karst conduit system  

Science.gov (United States)

This study shows the importance of catchment delineation for characterization of karst systems and interpretation of spring discharge curves for the well investigated karst springs Blautopf and Gallusquelle. The catchment areas of both springs belong to the deep karst of the Swabian Alb (Germany) and are characterized by carbonate series of the Upper Jurassic. However, the discharge behaviours of the springs differ considerably from one another. The baseflow of the Blautopf spring is significantly higher than that of the Gallusquelle spring. The scaling of the discharge with the catchment area shows that the reason therefore is the larger catchment area of the Blautopf spring. This conclusion is supported by the estimated baseflow recession coefficients, which are similar for both springs. It means that the hydraulic properties of the main aquifer storage, i.e. fissured matrix blocks, are in the same parameter range. However, the Blautopf spring displays a much higher variability of spring discharge than the Gallusquelle spring. This can be attributed to different degrees of karstification of both catchment areas. The ratio between maximum and minimum daily spring discharge is 32 cbm/s : 0,25 cbm/s ? 130 for the Blautopf catchment and 2,7 cbm/s : 0,04 cbm/s ? 67 for the Gallusquelle catchment during the period 1958-2009. In the Blautopf catchment a large scale water filled cave system is reported from speological investigations. In contrast, the Gallusquelle conduit system is not accessible. The evaluation of artifical tracer tests show that the water filled conduit volume in the Gallusquelle catchment is only a fraction of the Blautopf catchment. Normalized to the catchment area, the portion of the conduit system of the Blautopf is approximately twice as large as that of the Gallusquelle. It reveals the importance of the conduit system for groundwater flow in the investigated systems.

Geyer, T.; Selg, M.; Gudera, T.; Sauter, M.

2012-04-01

200

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

 
 
 
 
201

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)

202

Current distribution in Cable-In-Conduit Conductors  

Energy Technology Data Exchange (ETDEWEB)

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.

Ferri, M.A.

1994-05-01

203

Geophysical Methods for Locating Karst Conduits in Cane Run Watershed, Central Kentucky  

Science.gov (United States)

Cane Run watershed in central Kentucky was listed by the Kentucky Division of Water as one of four focus watersheds for clean-up under the State’s nonpoint-source pollution program. This watershed is degraded by pathogens, nutrients, siltation, and organic enrichment. The sources of pollution include both municipal point sources and nonpoint agricultural and nonagricultural sources. The relative contribution of different parts of the watershed to the contamination is not well understood, however. The geology of Cane Run watershed consists of Ordovician thin-bedded limestone with sparse interbeds of shale. The landscape is dominated by karst features such as sinkholes and springs. Cane Run only flows during times of significant rainfall, usually in the spring of the year. The remainder of the year, most water is recharged to a karst conduit system that leads from Lexington, Ky to Royal Spring, as demonstrated by groundwater tracing. Royal Spring is the major water supply for Georgetown in Scott County, Ky. We attempted to locate the karst conduit so that groundwater flowing through the conduit could be monitored. These monitoring data are essential for assessing the effectiveness of remediation plans. In 2008, based on geology, karst features, and hydrogeology, an initial round of electrical-resistivity and spontaneous-potential geophysical surveys were conducted to help pinpoint the location of the conduit at three sites. Fifteen exploratory boreholes were drilled on the basis of the geophysical results. The boreholes confirmed the geophysical surveys had located minor mud-filled conduits that were interpreted as tributaries to the main conduit. Another round of 2D and 3D electrical resistivity surveys were conducted in 2009 to search for the main conduit. The analysis of this round of surveys resulted in one promising site that is suspected to be in close proximity to the conduit. A time-lapse 2D electrical resistivity survey in conjunction with calcium chlorite solution injection was performed to pinpoint the conduit location. Microgravity measurements were also taken at the site to check whether the gravity anomaly signals are associated with conduits. The geophysical results will be further tested by exploratory boreholes. This work is being carried out in cooperation with the University of Kentucky’s College of Agriculture and Department of Earth and Environmental Sciences.

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

2009-12-01

204

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

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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

205

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

206

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

Science.gov (United States)

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

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

2014-06-01

207

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

Directory of Open Access Journals (Sweden)

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

M. Foroutan Koudehi

2014-07-01

208

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

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

LEGAULT A.

2003-07-01

209

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

Directory of Open Access Journals (Sweden)

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

M. Perne

2014-06-01

210

AMTEC vapor-vapor series connected cells  

Science.gov (United States)

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

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

1995-08-01

211

R-22 vapor explosions  

International Nuclear Information System (INIS)

Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

212

Ultraviolet metal vapor laser having hard sealed internal mirrors  

International Nuclear Information System (INIS)

This patent describes an ultraviolet metal vapor laser tube. It comprises: an elongated envelope; an active laser medium; an output coupling mirror assembly; a reflector mirror assembly; first mounting means; and a glass solder

213

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

214

Vaporization of ThC and (Th,U)C  

International Nuclear Information System (INIS)

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

215

Delivery of chondroitinase ABC and glial cell line-derived neurotrophic factor from silk fibroin conduits enhances peripheral nerve regeneration.  

Science.gov (United States)

Nerve conduits are a proven strategy for guiding axon regrowth following injury. This study compares degradable silk-trehalose films containing chondroitinase ABC (ChABC) and/or glial cell line-derived neurotrophic factor (GDNF) loaded within a silk fibroin-based nerve conduit in a rat sciatic nerve defect model. Four groups of silk conduits were prepared, with the following silk-trehalose films inserted into the conduit: (a) empty; (b) 1?µg GDNF; (3) 2 U ChABC; and (4) 1?µg GDNF/2 U ChABC. Drug release studies demonstrated 20% recovery of GDNF and ChABC at 6?weeks and 24?h, respectively. Six conduits of each type were implanted into 15?mm sciatic nerve defects in Lewis rats; conduits were explanted for histological analysis at 6?weeks. Tissues stained with Schwann cell S-100 antibody demonstrated an increased density of cells in both GDNF- and ChABC-treated groups compared to empty control conduits (p?Conduits loaded with GDNF and ChABC also demonstrated higher levels of neuron-specific PGP 9.5 protein when compared to controls (p?conduits possess favourable mechanical and degradative properties and are further enhanced when loaded with ChABC and GDNF. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25424415

Sivak, Wesley N; White, James D; Bliley, Jacqueline M; Tien, Lee W; Liao, Han Tsung; Kaplan, David L; Marra, Kacey G

2014-11-25

216

Long Term Complications Following Heal Conduit Urinary Diversion after Radical Cystectomy  

International Nuclear Information System (INIS)

To study the long term complications of ileal conduit urinary diversion in 36 patients with invasive urinary bladder cancer who lived more than 5 years after surgery. Patients and Methods: A retrospective study included 36 long term survivors (survival 5 years or greater) with invasive bladder cancer who did radical cystectomy or anterior pelvic excentration with ileal conduit urinary diversion at the National Cancer Institute, Cairo University before January 2004. Results: A total of 36 patients, 28 Males and 8 females, with median age at surgery of 62 years. Complications developed in 22 (61 %) patients and surgical re-intervention was needed, in 14 patients (39%). Stoma related complications developed in 7 (19%) patients, bowel related complications developed in 4 (11%), urinary tract infection and pyelonephritis was observed in 9 (25%) patients, conduit/ureteral anastomosis related complications developed in 5 (14%) patients, urolithiasis developed in 4 (11%) patients. Renal function deterioration (morphological and functional) was observed in 9 (25%) patients, nephrectomy was required in 2 patients, hemodialysis was required in 1 patient, and 1 patient had persistent hyperchloraemic acidosis. Conclusion: Long term follow-up for patients with ileal conduit urinary diversion shows high complication and high surgical re-intervention rates following this technique. Longer follow-up period for 20 or more years is needed for all urinary diversion techniques to prove either the ileal conduit will remain the gold standard for urinary diversion or other newly developed techniques will take its place

217

Midterm results of bovine jugular vein conduit for right ventricular outflow tract reconstruction  

International Nuclear Information System (INIS)

Objective: To evaluate the midterm results of Contegra conduit. Methods: The retrospective study comprised patient record at Aga Khan University Hospital, Karachi, of conduits implanted between May 2007 and June 2012. Data collection was made from the clinical notes and from serial echocardiograms by a single cardiologist. The last followup echocardiography was done at the time of data collection in June 2012. SPSS 19 was used for statistical analysis. Results: A total of 18 conduits had been implanted (16-22mm) during the study period. Median age at the time of surgery was 9 years (range: 2.5-16 years). Early mortality was seen in 3 (16.66%) patients, but none was Contegra related. Of the remaining 15 patients, 2 (13.33%) with a diagnosis of Pulmonary Atresia-Ventricular Septal Defect with hypoplastic peripheral Pulmonary Arteries (PA), developed severe distal pressure gradient (50mmHg) across Contegra over a median period of 18 months (range: 12-24 months), with resultant severe regurgitation and needed percutaneous intervention. There was no thrombosis, calcification, anuerysmal dilation or late deaths. Conclusion: At midterm followup, Contegra conduit was associated with low re-intervention rates with satisfactory haemodynamic results. However, long-term durability must be determined for this conduit, especially in patients with Pulmonary Atresia-Ventricular Septal Defect with hypoplastic peripheral Pulmonary Arteries. (author)thor)

218

Electrospun polycaprolactone/polylactic acid nanofibers as an artificial nerve conduit  

International Nuclear Information System (INIS)

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

219

Response of a volcanic conduit to step-like change in magma pressure  

Science.gov (United States)

Freely damped oscillations associated with strain offsets were observed by a nearby volumetric strainmeter during the 1986 Izu-Oshima Volcano eruption, Japan. These events are interpreted as a response of the magma-filled conduit to step-like changes in magma pressure. There were dramatic changes in the characteristic frequency of oscillation and the polarity of initial motion before and after the 6-hour interval of the enormous ground deformation due presumably to magma intrusion. The frequency changed from 42.6 to 21.3 mHz and the polarity changed from contraction to expansion. We propose a conceptual conduit model to explain this polarity reversal, where magma is episodically supplied to the conduit before but is episodically drained back to the reservoir after an extensive magma escape away from the reservoir as dike intrusion. Stress caused by the dike intrusion is large enough to break the lid of the conduit, thus to change a boundary condition. This change in boundary condition reduces the frequency of oscillation by a factor of 2. In this model longitudinal wave speed of the magma fluid is 340 m/s if the conduit length is taken to be 4 km.

Fukao, Yoshio; Fujita, Eisuke; Hori, Sadaki; Kanjo, Kenji

220

Program CICC flow and heat transfer in cable-in-conduit conductors  

International Nuclear Information System (INIS)

Computer program CICC has been written for use in the thermo-fluids design of superconducting magnets for tokamak reactors, which use forced-flow, helium-cooled, cable-in-conduit conductors (CICC). In addition to background heat loads that vary with space and time, these superconductors can develop normal zones that generate electrical resistance heat. Program CICC models the transient thermodynamic and fluid-dynamic system response to background heating and normal-zone propagation in the superconductor. The computational algorithm described in this paper couples a one-dimensional, compressible pipe-flow model (including flow choking) with two-dimensional, axisymmetric heat-conduction models of the superconductor cable, the conduit, and the epoxy-conduit insulation. National Institute of Standards and Technology helium properties are used. The model is verified by comparison with measured temperature and pressure profiles from thermal expulsion experiments. 10 refs., 9 figs

 
 
 
 
221

Program CICC flow and heat transfer in cable-in-conduit conductors  

Energy Technology Data Exchange (ETDEWEB)

Computer program CICC has been written for use in the thermo-fluids design of superconducting magnets for tokamak reactors, which use forced-flow, helium-cooled, cable-in-conduit conductors (CICC). In addition to background heat loads that vary with space and time, these superconductors can develop normal zones that generate electrical resistance heat. Program CICC models the transient thermodynamic and fluid-dynamic system response to background heating and normal-zone propagation in the superconductor. The computational algorithm described in this paper couples a one-dimensional, compressible pipe-flow model (including flow choking) with two-dimensional, axisymmetric heat-conduction models of the superconductor cable, the conduit, and the epoxy-conduit insulation. National Institute of Standards and Technology helium properties are used. The model is verified by comparison with measured temperature and pressure profiles from thermal expulsion experiments. 10 refs., 9 figs.

Wong, R.L. (Lawrence Livermore National Lab., CA (USA))

1989-11-20

222

Magma fracture and hybrid earthquakes in the conduit of Augustine Volcano  

Science.gov (United States)

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

Buurman, Helena; West, Michael E.

2013-12-01

223

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

224

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

225

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.

226

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

227

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 3 cm. 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

228

Vapor pumps and gas-driven machines  

International Nuclear Information System (INIS)

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

229

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

International Nuclear Information System (INIS)

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

230

Depressurizations of Fine Powders in a Shock Tube and Dynamics of Fragmented Magma in Volcanic Conduits and Lava Dome Explosions  

Science.gov (United States)

Samples of fine glass beads (mean grain size equal to 38 and 95 microns) have been suddenly depressurized within a shock tube. These short-lived, rapid decompressions simulate discrete, cannon-like vulcanian explosions and produce two-phase flows that are inhomogeneous in density in both vertical and horizontal directions. Observed flow velocities increase from approximately 2 to 12 m/s when the pressure drop increases from 200 to 900 mbar. Scaling criteria enable estimates of possible size of decompressing volcanic systems (approximately between 10 and 840 m) and possible velocities of volcanic flows (approximately between 35 and 290 m/s) that correspond to our experiments. At high pressure drops, as the mixture expands and moves up the tube the flow front becomes highly irregular and bubble-like voids form. The shape of these voids becomes also distorted and stretched in the turbulent flow. At relatively low pressure drops the samples oscillate because the fragments, after the expansion, flow back and bounce upward again. Jets with diameter smaller than that of the tube are shot out of the oscillating samples generating independent pulses. Large voids whose diameter is an important fraction of the tube diameter can also discretize the flows. A question arises then if similar mechanisms in real volcanoes can produce discrete flows within the conduit and pulse-like pyroclastic flows out of the vent. The rapid decompression of these powders results in their fluidization and for this reason we advance the hypothesis that also the fragmentation of magma within a volcanic conduit or the explosion of a lava dome results in the explosive fluidization of the generated fragments.

Cagnoli, B.; Sparks, S. R.

2001-12-01

231

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

232

Modélisation des connaissances et des systèmes pour la conception d'une aide à la conduite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

SILOE est un réacteur nucléaire de recherche du Commissariat à l'Énergie Atomique (CEA). Le Service du Réacteur SILOE (DRE/SRS) a initié la réalisation du système d'aide à la conduite ALEXIS, en vue d'améliorer la disponibilité de l'installation. ALEXIS est un système pilote prenant en compte les parties essentielles de l'installation. Il est actuellement opérationnel en salle de conduite. Le développement d'une aide à l'opérateur reste difficile car il est nécessaire de maî...

Monge, F.; Royer, Jean-claude; Ermine, Jean-louis; Baradel, C.

1997-01-01

233

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)

234

Retrograde exchange of heavily encrusted ureteric stents via the ileal conduit: a technical report  

International Nuclear Information System (INIS)

We describe two cases of retrograde ureteric stent exchange of heavily encrusted ureteric stents (JJ) via tortuous ileal conduits. The blocked ureteric stents were snared from inside the conduit so they could be accessed and a wire inserted. The lumens of the stents were unblocked with a wire but the stents could not be withdrawn due to heavy encrustation of the ureteric stent in the renal pelvis. A stiff wire was inserted to provide support and a 9 French peel away sheath was used to remove the encrustations allowing the stents to be withdrawn and exchanged. This is a safe and successful technique allowing ureteric stents to be removed when heavily encrusted.

235

Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Directional drilling at Unzen Volcano in Japan during mid of 2004 penetrated the magma conduit and successfully recovered samples of the lava dike that is believed to have fed the 1991–1995 eruption. The dike was sampled about 1.3 km below the volcano’s summit vent and is intruded into a broader conduit zone that is 0.5 km wide. This zone consists of multiple older lava dikes and pyroclastic veins and has cooled to less than 200 ?C. The lava dike sample was unexpe...

Kozo Uto; Setsuya Nakada

2005-01-01

236

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.

1992-06-01

237

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

238

Gastric conduit-preserving, radical pancreaticoduodenectomy with microvascular reconstruction for pancreatic head cancer after esophagectomy: report of a case.  

Science.gov (United States)

Pancreaticoduodenectomy is a radical treatment for pancreatic head cancer. However, it is sometimes difficult to perform pancreaticoduodenectomy, particularly in patients who have previously undergone esophagectomy with gastric conduit reconstruction. We herein describe a surgical technique for radical pancreaticoduodenectomy with microvascular reconstruction that preserves the gastric conduit. A 72-year-old male with a previous history of esophagectomy and gastric conduit reconstruction for esophageal cancer was referred to our hospital for surgical treatment of advanced pancreatic head cancer. After considering both the cancer curability and preservation of the gastric conduit, we performed a standard pancreaticoduodenectomy, and added a microvascular anastomosis of the gastroduodenal artery to the right gastroepiploic artery. In addition, we also performed reconstruction of the right gastroepiploic vein. This radical pancreaticoduodenectomy with microvascular reconstruction was safely and successfully performed, and it preserved the gastric conduit. The 6-month follow-up showed recurrence-free survival and a good quality of life. PMID:24264060

Inoue, Akira; Akita, Hirofumi; Eguchi, Hidetoshi; Hama, Naoki; Wada, Hiroshi; Kawamoto, Koichi; Kobayashi, Shogo; Mori, Masaki; Doki, Yuichiro; Nagano, Hiroaki

2014-04-01

239

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

Directory of Open Access Journals (Sweden)

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.

Hassan A. Abol-Enein

2008-01-01

240

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

Science.gov (United States)

...stating that the proposed project is no longer economically practicable.\\3\\ The project would have been located...conduit exemption for Project No. 11651 on June 7, 1999. Calleguas Municipal Water District, 87 FERC...Commission's regulations states that if no...

2011-08-29

 
 
 
 
241

Coxiella burnetii infection of a bovine jugular vein conduit in a child.  

Science.gov (United States)

We report a case of an 11-year-old girl with Coxiella burnetii infection of a bovine jugular vein conduit which is an extremely rare manifestation of Q fever. The role of surgery in the management of C. burnetii endovascular infection and the use of serology are discussed. PMID:22349674

Tasher, Diana; Stein, Michal; Raucher-Sternfeld, Alona; Somekh, Eli

2012-06-01

242

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

Science.gov (United States)

It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were cally observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. Masson's trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cells on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects. PMID:25206536

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

2013-01-01

243

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

244

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

245

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

246

A process-based reactive hybrid transport model for coupled discrete conduit continuum systems  

Science.gov (United States)

SummaryA process-based reactive hybrid transport model, RUMT3D, was developed to quantify the fate of dissolved contaminants and their interaction with solid phases in domains where discrete conduit networks are embedded in a permeable matrix. Such hybrid systems can be found, for example, in flooded underground mines, discrete karstic and fractured systems as well as in aquifers with intersecting boreholes. RUMT3D specifically takes into account the two distinctly different transport regimes within such hybrid systems: (i) rapid transport within the network of the highly conductive conduits, shafts, drifts, ventilation raises or roadways and (ii) the low velocity regime within the considerably less permeable matrix. RUMT3D is an extension of the existing reactive transport model PHT3D. Compared to the original model, which combines the multi-species transport simulator MT3DMS with the geochemical model PHREEQC-2, RUMT3D additionally incorporates a conduit transport model. A benchmark problem simulating the principal processes occurring at contaminated sites affected by acid mine drainage (AMD) was used to evaluate the model. The results suggest that for the simulation of contaminant transport in a hybrid system the consideration of rapid transport pathways is necessary. Conduits can strongly affect groundwater hydraulics and therefore become responsible for rapid hydrochemical changes.

Spiessl, Sabine M.; Prommer, Henning; Licha, Tobias; Sauter, Martin; Zheng, Chunmiao

2007-12-01

247

Analogue modelisation of flow through a double porosity media with discrete conduits  

Science.gov (United States)

In this study we describe a three dimensional meter scale experimental system used to investigate flow through a double porosity media that includes discrete flow conduits. This hybrid discrete-continuum approach is used to simulate water flow in karstic carbonate aquifers. A rectangular tank is filled with stacked ceramic foam blocks laterally separated with a constant aperture. The tank outlet is connected to a drilled conduit network that follows the overlying aperture scheme at the lower base of the system. Above the system, an artificial rain is set with a sprinkler. Working with an analogue model seems interesting as materials, initial and boundary conditions are fully known. Ceramic foam provides a uniform matrix material allowing different porosities and hydraulic conductivities. The modulability of the aperture pattern and size let different experiment setting possibilities. A variation in the drilled number of holes in the conduit network will change its draining capacity. And, finally the artificial rain rate and location are well characterized. The system is adequately instrumented in order to 1) observe hydraulic head distributions in both matrix and fracture medium and 2) record spring flow fluctuations. Moreover, any experience is very reproducible. This analogue modeling approach allows an observation of both fracture and matrix flow contribution to a spring with a drained double porosity media with discrete conduits. Comparison of in situ measured data with a finite element numerical model and an analytical solution are shown.

Hakoun, V.; Pistre, S.; Karst; heterogeneous media-Hydrogeology, hydraulics; transfers

2011-12-01

248

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. PMID:21371024

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

2012-01-01

249

Comparison of divided sciatic nerve growth within dermis, venous and nerve graft conduit in rat  

Science.gov (United States)

BACKGROUND: Considering the common origin of skin and peripheral nervous system, a tube of dermal layer of skin hypothetically can be an ideal conduit for nerve reconstruction. An experimental study performed to evaluate the nerve regeneration of efficacy into a dermal tube. METHODS: Sixty male Wistar rats were used. A 10 mm gap was produced in right sciatic nerves. In group A the autogenous nerve grafts were used to bridge the defects. In group B vein conduit were use to reconstruct the gaps. In group C dermal tube were used to bridge the defects. Morphologic studies were carried out after 3 month. RESULTS: The density of nerve fibers was significantly higher in autogenous nerve graft group. The efficacy of nerve growth into the dermal tube group was significantly poor in comparison to other groups. CONCLUSIONS: In the present study, dermis was used as the nerve conduit for the first time. This study indicates that the dermal tube is not a suitable conduit for nerve regeneration till further studies to resolve the problems before clinical application. PMID:21526083

Fatemi, Mohammad Javad; Foroutan, Kamal Seyed; Ashtiani, Abass Kazemi; Mansoori, Maryam Jafari; Vaghardoost, Reza; Pedram, Sepehr; Hosseinpolli, Aidin; Rajabi, Fatemeh; Mousavi, Seyed Jaber

2010-01-01

250

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 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

251

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.

252

Muonium formation in vapors  

International Nuclear Information System (INIS)

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

253

Application de la systémique à la conception d'un modèle de conduite en mode dégradé d'une centrale nucléaire  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cette publication présente un modèle de conduite d'une centrale nucléaire en mode dégradé fondé sur l'élaboration conjointe de trois modèles. Le premier décrit l'ensemble des phénomènes physiques pertinents pour le pilotage d'une centrale nucléaire, le second l'ensemble des activités de conduite d'un opérateur, le troisième une procédure de conduite en mode dégradé d'une centrale nucléaire. La finalité de ce modèle est d'expliquer à un opérateur cette conduite.

Millerat, Pierre; Chaillot, Mathias; Ermine, Jean-louis

1996-01-01

254

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

255

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

Science.gov (United States)

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

Kolzenburg, S.; Russell, J. K.

2014-07-01

256

Melt flow in a conduit and seismic signals time evolution: a laboratory study  

Science.gov (United States)

A variety of seismic signals have been related to fracturing and magma transport in the volcanic edifice. Previous studies have provided a first experimental support to this association by reproducing fluid generation and migration while recording seismic signals in a layered sample comprising an olivine-MORB-olivine sandwich. Here, we developed a new experimental set up, consisting in a melt reservoir beneath a volcanic conduit, which allowed a much better control on the physical mechanisms taking place and the related seismic signals. Experiments up to 1373K and 300MPa confining pressure were carried out using an internally-heated Paterson gas apparatus especially designed for the measurements of physical properties of rocks. Acoustic emissions were measured during heating of cold pressed synthetic aggregate of MORB powder till complete melting. High frequency events were recorded at 750-960K, corresponding to glass transitions in the MORB glass (Giordano and Dingwell, 2003). A long lasting low frequency event took place at 1200K, corresponding to melt migration in the conduit, followed by high frequency events, related to brittle intrusive mechanisms due to the magma intrusion in the brittle medium at the top of the conduit. Experiments were also carried out on higher (î2 order of magnitudes) viscosities aggregates of Fish canyon tuffs, and varying the length of the conduit (from 3 to 15mm). Results highlight the seismic features related to the intrusion of the silicic magma in the conduit. Repeated occurrence both of swarms of high frequency events and long lasting signals at 500-1000K took place, followed from episodes of steady long lasting events at 1000-1273K. A direct relationship between seismic waveforms + spectrograms and physical phenomena can be assessed, by scaling length and frequency. These evidences provide solid and well constrained new experimental insight into magma migration in the lithosphere and the mechanism of dyke emplacement in volcanic edifices

Vinciguerra, S.; Caricchi, L.; Burlini, L.

2007-12-01

257

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

258

Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines  

International Nuclear Information System (INIS)

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

259

Vacuum vapor and passive cryogenic vapor extraction technology comparative field test for subsurface soil vapor sampling  

Energy Technology Data Exchange (ETDEWEB)

This document investigates two methods of sampling subsurface vapors. The methods discussed are Vacuum/Vapor extraction system and Passive Cryogenic Vapor Extraction system. This report gives an overview of both technologies and outlines the preliminary tests of the two technologies.

Motes, B.G.; Bird, S.K.; Sense, R.R.

1994-05-01

260

Stratified vapor generator  

Science.gov (United States)

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

 
 
 
 
261

[Development and evaluation of a prosthetic valved conduit dilated by percutaneous approach: experimental study in the lamb].  

Science.gov (United States)

This study was undertaken to develop a dilated valved conduit for reconstruction of the right ventricular outflow tract in the animal. The conduits were made by sewing a valved tube (Medtronic Inc) inside a vascular stent (Numed Inc). After preparation, they were inserted surgically in five lambs. The conduits were then dilated 6 weeks and 3 months after their implantation. Before sacrificing the animals at 3 months, a 22 mm valved stent was implanted percutaneously inside the surgical conduits. One animal died suddenly due to kinking of the conduit. Balloon dilatation was performed in the surviving animals. The first dilatation only had a modest impact on valvular function but it was much aggravated after the second dilatation. A valved stent was successfully inserted percutaneously. At sacrifice, all the conduits were completely engulfed in an intense fibrosis. In conclusion, a valved biological conduit for reconstruction of the right ventricular ejection tract has been developed and can be dilated sequentially to follow growth. The new product could have an important role to play in the management of congenital malformations involving the right ventricular outflow tract. PMID:16802727

Boudjemline, Y; Laborde, F; Pineau, E; Mollet, A; Abadir, S; Bonhoeffer, P; Bonnet, D; Sidi, D

2006-05-01

262

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

263

Role of co-vapors in vapor deposition polymerization.  

Science.gov (United States)

Polypyrrole (PPy)/cellulose (PPCL) composite papers were fabricated by vapor phase polymerization. Importantly, the vapor-phase deposition of PPy onto cellulose was assisted by employing different co-vapors namely methanol, ethanol, benzene, water, toluene and hexane, in addition to pyrrole. The resulting PPCL papers possessed high mechanical flexibility, large surface-to-volume ratio, and good redox properties. Their main properties were highly influenced by the nature of the co-vaporized solvent. The morphology and oxidation level of deposited PPy were tuned by employing co-vapors during the polymerization, which in turn led to change in the electrochemical properties of the PPCL papers. When methanol and ethanol were used as co-vapors, the conductivities of PPCL papers were found to have improved five times, which was likely due to the enhanced orientation of PPy chain by the polar co-vapors with high dipole moment. The specific capacitance of PPCL papers obtained using benzene, toluene, water and hexane co-vapors was higher than those of the others, which is attributed to the enlarged effective surface area of the electrode material. The results indicate that the judicious choice and combination of co-vapors in vapor-deposition polymerization (VDP) offers the possibility of tuning the morphological, electrical, and electrochemical properties of deposited conducting polymers. PMID:25673422

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

2015-01-01

264

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

265

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

266

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

Science.gov (United States)

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

Karlstrom, L.; Dunham, E. M.

2013-12-01

267

Methods for evaluating the effects of conduits at the surface of the sea  

Science.gov (United States)

The propagation of radio waves in the atmosphere is determined by the index of refraction which is sensitive to the pressure, temperature and moisture of the air. In the vicinity of the surface of the sea, there is a strong gradient of moisture related to the evaporation of water; it gives rise to a fast decrease of the index of the air creating a conduit of propagation in vicinity of surface. A source located in the interior of the conduit (i.e., at an altitude ranging between that of the minimum of the modified index and sea surface) sees most of its energy remaining captive inside this conduit. This has as an operational consequence - a considerable increase in the range of the radio hardware working in the vicinity of the surface of the sea. In addition, the propagation inside the conduit is characterized by the presence of multipaths related to the successive reflection of the electromagnetic wave on the surface of the sea and the boundary of the conduit. What results is a series of reinforcements and attenuations of the field being propagated in the conduit. Taking into account the practical importance of these effects it is advisable to have suitable methods of evaluation. In this talk three methods are examined: (1) parabolic equation method, (2) method of modes, and (3) method of geometrical optics. The parabolic equation method consists of making an approximation of the wave equation by supposing that the field is propagated around a primary direction. Under these conditions one reduces the equation of propagation to a partial derivative equation of parabolic type which leads to an easy algorithm to work with. The method of modes makes it possible to carry out calculations in an entirely analytical way by supposing that the profile of the index follows a simple law. This method constitutes an analytical reference with respect to the two other methods which are numerical. The method of geometric optics is an asymptotic method. It consists of considering the trajectory of the rays resulting from the source by solving the eikonal equation. The intensity of the electromagnetic field can be given in conjunction with the equation of the trajectories; the calculation of the divergence of the wave vector tangent to the ray passing by the point where the field is evaluated. One thus obtains a system of ordinary differential equations which can be solved numerically by the method of Runge-Kutta. Each one of these methods is analyzed and a comparison between them is carried out on a number of concrete examples. In each case the theoretical limits, the advantages, and the limits of use of the three methods are highlighted.

Fournier, Michel

1994-07-01

268

Study on the Heat Transfer Numerical Analysis of Supper Low Temperature Liquefied Gas Vaporizer  

International Nuclear Information System (INIS)

Liquefied gas vaporizer means machine to vaporize the liquefied gas as liquid nitrogen(LN2), liquefied natural gas(LNG), liquid oxygen(LO2) etc. In the air type vaporizer, the frozen dew is also created by temperature drop (below 273 K) on vaporizer surface. This problem increases as the time progresses and humidity increases. In addition, the frozen dew gradually becomes frost deposit consequently, heat transfer through vaporizer decreases because frost deposit form adiabatic sheet. Because of this reason, recent vaporizer system is installed as parallel type, this vaporizer system needs more expensive installation costs and more space. This paper was investigated on the heat transfer characteristics of liquefied gas vaporizer with super low temperature and this paper was carried out the numerical about air heating vaporizer with super low temperature. The numerical analysis on the heat transfer was studied on the effect of geometric parameters of the vaporizer, which are length 1000 mm of 4fin75le type vaporizer. 4fin75le means number of fin is 4 and height of fin is 75 mm

269

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 (2mg/ml) directly to collagen-filled nerve conduits in the rat sciatic nerve transection model. Analysis of myelinated axons and retrogradely labeled motoneurons as well as functional 'CatWalk' video analysis did not reveal significant differences between vehicle controls and leupeptin treated animals. Therefore, leupeptin does not improve nerve regeneration via protease inhibition in regrowing axons or in surrounding Schwann cells following a single application to a peripheral nerve conduit suggesting indirect effects on motor endplate integrity if applied systemically. PMID:24631569

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

2014-04-30

270

Evaluation of cable tray and conduit systems using the seismic experience data base  

International Nuclear Information System (INIS)

Cable tray and conduit systems have an excellent earthquake performance record. This has been evidenced at over 70 power and industrial facilities in 14 past major earthquakes, and is reinforced by shake table test data and detailed analyses. A method is developed for utilizing this data in defensible, simple seismic qualification criteria and configuration controls. Qualitiative comparisons are used to demonstrate the applicability of the data base to the given cable tray/conduit system. Quantitative assessments are used to guarantee that the support system is as least as adequate as the data base support systems that survived without apparent damage. The results are incorporated into field evaluation guidelines and also form the basis for configuration control criteria. This method results in significant cost savings to nuclear utilities, realized at the engineering effort, plant hardware modification, and documentation levels. (orig.)

271

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.

272

Deposition of UO2 in Sampling Conduits in a Centralized Air-Monitoring System  

International Nuclear Information System (INIS)

Investigations have been carried out to clarify to what extent a static monitoring system with centralized sampling could be used with reasonable reliability to detect uranium contamination in laboratory air. A multichannel air-monitoring system with centralized sampling, using filter-paper collection, has been the basis for experiments to examine the degree of deposition in the sampling conduit from a UO2 Pellet Production Plant to the monitoring room. The sampling point is separated from the detector unit by PM-Dura pipe, 3/4 in. diam. and 28 m long. The difference in vertical direction is about 6 m. Eleven 90° bends are incorporated in the system. The paper discusses the results obtained, and shows the loss and relative distribution of UO2 in the conduit system. (author)

273

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

274

Effect of the thermal barrier on the stability of cable-in-conduit conductors  

International Nuclear Information System (INIS)

As the enhancement of stability margin of cable-inconduit conductors, the effect of thermal barrier provided inside the surface of strand has been investigated. First, by a simple model calculation, it is shown that the energy needed to raise the temperature of a strand as the simulation of the disturbance due to surface friction, depends strongly on the pulse duration and thermal conductivity of surface material. Next, as based on this consideration, strands with the thermal barrier inside its surface have been made and the stability test has been carried out. From the result, it was shown that the stability margin of a cable-in-conduit conductor consisting of strands with the thermal barrier can be calculated with the enthalpy of whole helium whithin the conduit even near the critical current

275

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

276

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

277

Optimization of Nb3Sn 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''. Nb3Sn 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

278

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

Science.gov (United States)

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

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

2014-12-01

279

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

280

Prion propagation in a nerve conduit model containing segments devoid of axons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Prions, the putative causative agents of transmissible spongiform encephalopathies, are neurotropic pathogens that spread to the central nervous system via synaptically linked neural conduits upon peripheral infection. Axons and their transport processes have been suggested as mediators of nerve-associated prion dissemination. However, the exact cellular components and molecular mechanisms underlying neural spread are unknown. This study used an established hamster scrapie model to pursue a n...

Kratzel, Christine; Kru?ger, Dominique; Beekes, Michael

2007-01-01

 
 
 
 
281

Simulation numérique de la convection naturelle laminaire dans une conduite verticale  

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Dans ce travail, nous présentons une étude numérique du phénomène de la convection naturelle laminaire dans une conduite verticale, dont la paroi est maintenue à une température constante. Les équations régissant ce phénomène, ont été résolues par une approche numérique basée sur la méthode des volumes finis. Nous avons représenté les champs de vitesses, de températures, et de pressions, ainsi que la variation du nombre de Nusselt moyen en fonction du nombre de Rayleigh. L...

Bakhti, Fatima Zohra; Siameur, Mohamed; Chehhat, Abdelmadjid

2007-01-01

282

Use of arterial conduit as an alternative technique in arterial revascularization during orthotopic liver transplantation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

BACKGROUND: The risk of hepatic artery thrombosis after orthotopic liver transplantation is higher in cases of poor hepatic arterial inflow, small or anomalous recipient hepatic arteries, unsafe native hepatic arteries. AIMS: To assess the use of arterial conduits as alternative technique for graft revascularization. PATIENTS: At the Liver Transplant Center of the 'S. Giovanni Battista' Hospital in Torino, a review has been made of 600 consecutive orthotopic liver transplantations in 545 adul...

Rizzetto, Mario; Salizzoni, Mauro

2002-01-01

283

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

284

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

285

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 epin...

Peixun Zhang, Na Han

2013-01-01

286

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

287

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

288

Lymphatic pump-conduit duality: contraction of postnodal lymphatic vessels inhibits passive flow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Lymphangions, the segments of lymphatic vessels between valves, exhibit structural characteristics in common with both ventricles and arteries. Although once viewed as passive conduits like arteries, it has become well established that lymphangions can actively pump lymph against an axial pressure gradient from low-pressure tissues to the great veins of the neck. A recently reported mathematical model, based on fundamental principles, predicted that lymphangions can transition from pump to co...

Quick, Christopher M.; Ngo, Bruce L.; Venugopal, Arun M.; Stewart, Randolph H.

2009-01-01

289

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 sternocl...

Young Jo Sa; Young Du Kim; Chi Kyung Kim; Jong Kyung Park; Seok Whan Moon

2013-01-01

290

Laparoscopic Repair of Ileal Conduit Parastomal Hernia Using the Sling Technique  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Laparoscopic parastomal hernia repair has become a viable option to overcome the challenges that face the hernia surgeon. Multiple techniques have been described over the last 5 years, one of which is the lateralizing “sling” technique, first described by Sugarbaker in1980. In this study, we report the technique and our early results with the laparoscopic modified Sugarbaker repair of parastomal hernias after ileal conduit.

Mirza, Brian; Chand, Bipan

2008-01-01

291

Contribution des communications intervéhiculaires pour la conception de systèmes avancés d'aide à la conduite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Les systèmes avancés d'assistance à la conduite automobile ont comme objectif d'apporter de l'intelligence au véhicule en l'équipant d'un ensemble de capteurs extéroceptifs et proprioceptifs. L'approche classique consiste à doter le véhicule de capacités de perception pour lui permettre de connaître son environnement sans interaction intelligente avec cet environnement. Cette approche dite autonome a montré cependant des limites liées à la portée et à la précision des capteurs...

Ammoun, Samer

2007-01-01

292

Controls on the explosivity of scoria cone eruptions: Magma segregation at conduit junctions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Violent strombolian (transitional) eruptions are common in mafic arc settings and are characterized by simultaneous explosive activity from scoria cone vents and lava effusion from lateral vents. This dual activity requires magma from the feeder conduit to split into vertical and lateral branches somewhere near the base of the scoria cone. Additionally, if the flow is separated, gas and liquid (+ crystals) components of the magma may be partitioned unevenly between the two branches. Because f...

Pioli, Laura; Azzopardi, B. J.; Cashman, K. V.

2009-01-01

293

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)

294

Inhibition of vasoconstriction by potassium channel opener aprikalim in human conduit arteries used as bypass grafts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AIMS: Potassium channel openers (KCOs) are of potential therapeutic value. Little is known about the effect of these drugs on human conduit arteries used as coronary bypass grafts. The purpose of this study was to determine the effect of the KCO aprikalim (RP52891) on human arteries used as coronary bypass grafts with emphasis on the possible difference in the inhibitory effect on depolarizing agent-mediated rather than receptor-mediated contraction. METHODS: Human internal mammary artery seg...

He, Gw; Yang, Cq

1997-01-01

295

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

Science.gov (United States)

...Allocation of allocable investment expenses —(1) In general. A real estate mortgage investment conduit or REMIC (as...aggregate amount of allocable investment expenses of the REMIC for...other than a nonresident alien whose income with...

2010-04-01

296

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.)

297

Hydrazine-Vapor Samplers  

Science.gov (United States)

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

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

1994-01-01

298

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

299

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

DEFF Research Database (Denmark)

Fifty consecutive patients had ileal conduits constructed with a technically and quick simple antireflux ureteroileal anastomosis. Complications related to the ureteral implantation were studied retrospectively, and at follow-up (8 months-12 years later, median 3 years) conduit dysfunction and ureteral reflux were assessed in 18 patients out of the 25 patients who were still alive. Early complications and signs of late upper urinary tract deterioration were similar to those found after other operative techniques had been used. One patient had a postoperative urinary leak from the uretero ileal anastomosis. which was treated successfully by two weeks drainage. Hydronephrosis deteriorated in 18 (26%) of the renal units, remained unchanged in 39 (57%) and improved in 11 (16%). Increases in plasma creatinine concentrations up to 200 mumol/l were found in eight patients, and in one patient it increased from 300 to 420 mumol/l. Partial ureteral reflux was present in three (2 patients) of 33 ureters studied and minimal conduit dysfunction was found in 8 patients. In conclusion we find this method of urinary diversion to be quick, easy, and safe.

Bernstein, I T; Bennicke, K

1991-01-01

300

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.

L. PEREIRA

1999-12-01

 
 
 
 
301

Preparation and evaluation of novel nano-bioglass/gelatin conduit for peripheral nerve regeneration.  

Science.gov (United States)

Peripheral nerves are exposed to physical injuries usually caused by trauma that may lead to a significant loss of sensory or motor functions and is considered as a serious health problem for societies today. This study was designed to develop a novel nano bioglass/gelatin conduit (BGGC) for the peripheral nerve regeneration. The bioglass nanoparticles were prepared by sol-gel technique and characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis. The interfacial bonding interaction between the nano-bioglass and gelatin in the developed conduits was assessed by FTIR. The surface morphology and pore size of the nanocomposite were investigated through scanning electron microscopy with the pore size of the conduits being 10-40 ?m. Biocompatibility was assessed by MTT assay which indicated the BGGC to have good cytocompatibility. The guidance channel was examined and used to regenerate a 10 mm gap in the right sciatic nerve of a male Wistar rat. Twenty rats were randomly divided into two experimental groups, one with the BGGC and the other being normal rats. The gastrocnemius muscle contractility was also examined at one, two and three months post-surgery in all groups using electromyography (EMAP). Histological and functional evaluation and the results obtained from electromyography indicated that at three months, nerve regeneration of the BGGC group was statistically equivalent to the normal group (p > 0.05). Our result suggests that the BGGC can be a suitable candidate for peripheral nerve repair. PMID:24186149

Koudehi, Masoumeh Foroutan; Fooladi, Abbas Ali Imani; Mansoori, Kourosh; Jamalpoor, Zahra; Amiri, Afsaneh; Nourani, Mohammad Reza

2014-02-01

302

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.

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

1999-12-01

303

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

304

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

International Nuclear Information System (INIS)

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

305

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

306

Prediction of the remaining service life of the bends of the steam conduits at various stages of creep  

Science.gov (United States)

The present paper reports the generalized results of an investigation concerning microdamage of metal (Cr-Mo-V steels) in the bends of the steam conduits after their service under different conditions and after their rupture. The basic temperature-time and force dependences of kinetics of the bends failure on the quality of their manufacture, operating conditions, and level of cumulative microdamage are constructed. These dependences may be helpful when evaluating the remaining service life of the steam conduits.

Mintz, I. I.; Khodykina, L. E.

2013-06-01

307

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Because conduit systems in maturely developed karst aquifers have a low hydraulic resistance, aquifers drain easily and karst aquifers are subdivided into well-defined ground water basins. Ground water elevations are highest at basin boundaries; lowest at the spring where the ground water is discharged. Parameters that control the type of conduit development are (1) the effective hydraulic gradient, (2) the focus of the drainage basin, and (3) the karstifiability of the bedrock. Moderate to h...

White, W. B.; White, E. L.

2003-01-01

308

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

309

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...

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

2011-01-01

310

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

311

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

312

Dynamics of Conduit Flow and Fragmentation of Trachytic Versus Rhyolitic Eruptions  

Science.gov (United States)

We have performed a systematic investigation of the dynamics of ascent and fragmen- tation of trachitic magmas from Phlegrean Fields, and have compared such dynamics with those of the more common and more thoroughly investigated rhyolitic eruptions. The investigation involved experimental as well as numerical studies. Knowledge of the viscosity of trachytic magmas is crucial, since viscosity is one of the most im- portant controlling factors in magma ascent dynamics. We have performed a series of measurements of the dry and hydrous viscosity of trachytic liquids representative of the glassy portion of pumice from the Campanian Ignimbrite, Agnano Monte Spina, and Monte Nuovo eruptions of Phlegrean Fields, spanning a time interval from 36,000 BP to 1538 AD, and an intensity range of about 4 orders of magnitude. The results show that for water contents larger than 1-2 wt% trachytic viscosities are within one order of magnitude less than rhyolitic viscosities. On the contrary, the calculated sol- ubility of water in trachytic liquids is significantly higher than in rhyolitic liquids. We have simulated the steady, multiphase flow of gas and liquid magma, or pyro- clasts above fragmentation, for trachytic and rhyolitic compositions, by parameteris- ing quantities like the total water content and the conduit size. All else being equal, the higher water solubility of trachytes and substantially similar liquid viscosity with respect to rhyolites yields a lower mixture viscosity and lower pressure gradient in the deep conduit region for the former magma type. This results in the achievement of fragmentation conditions, calculated as the condition at which the strain rate in magma becomes too large to be supported by viscous flow, which are hundreds to thousands of meters higher in the conduit for trachytes than for rhyolites. The fragmentation vesic- ularity of trachytes is also systematically larger than that of rhyolites, still remaining in the 0.6 U 0.85 range which is typical of pumice from magmatic eruptions through- out the world. In spite of such large differences in the internal conduit dynamics, the conduit exit conditions are remarkably similar for the two magma types (all other conditions being equal), according to the similar large scale features of rhyolitic and trachytic explosive eruptions. Finally, despite the lower magma viscosity of trachytes with respect to rhyolites, the delayed fragmentation and longer high-viscosity bubbly flow region of the former can result in larger overall mechanical energy dissipation by viscous forces, and lower mass flow rates for trachitic than for rhyolitic eruptions.

Papale, P.; Giordano, D.; del Seppia, D.; Romano, C.; Dingwell, D. B.

313

Conduit Processes Driving Pre-explosive Harmonic Tremor in the 2009 Redoubt Volcano Eruption  

Science.gov (United States)

During the 2009 eruption of Redoubt Volcano, Alaska, gliding harmonic tremor was observed before many vulcanian explosions. Though harmonic tremor is relatively common at volcanoes, the high fundamental frequency of these tremors (up to 30 Hz) is unique and of particular interest. Hotovec et al. (JVGR, 2013) linked this tremor to rapidly repeating magnitude ~1 earthquakes located a few kilometers beneath the vent. These events might be occurring as brittle failure of the magma or as slip along the margins of an obstruction within the conduit. Using a frictional faulting model, Dmitrieva et al. (Nature Geoscience, 2013) converted the seismicity and tremor signals into an estimate of the history of shear stresses acting on the fault surface and causing slip. Stressing rates increased, in a nonlinear manner, from less than 1 MPa/s to about 20 MPa/s over the final ten minutes before the explosions. Here we investigate what conduit processes could plausibly be responsible for such high stressing rates. One possibility is that a blockage develops in the conduit prior to each explosion, perhaps from a crystal-rich magma plug or collapse of the conduit walls. This obstacle temporarily prevents upward flow of magma, while deeper influx from below thus compresses and pressurizes magma in the conduit beneath the blockage. This compression largely occurs between the base of the obstruction and the H2O exsolution depth, which petrologic estimates of volatile content and standard solubility laws suggest is nominally located about a kilometer or two deeper than the blockage. We solve the unsteady conduit flow equations (mass and momentum balance for a compressible, viscous mixture of gas and liquid). Gas exsolution is treated with Henry's law, and in our present models exsolution begins abruptly below a critical pressure. No flow is permitted past the blockage and the system is driven by steady influx at depth. We find that as magma accumulates within the conduit beneath the blockage, pressure on the base of the obstruction (which, through force balance, is proportional to shear stress on its margins) rises in a nonlinear manner. This is because the effective compressibility of the system decreases as the exsolution depth rises in response to increasing pressure. Preliminarily results suggest that this model can reproduce the nonlinear increase toward the very high stressing rates inferred from the seismicity and tremor data, without requiring additional temporal variations in magma influx rate. In the coming months, we plan to compare predicted volumes of magma accumulated in the pre-explosive period with estimates of erupted volume in each explosion. Additional constraints might also be placed on our model using geodetic deformation observations. We also plan to extend our modeling into the explosion phase itself, by rapidly removing the blockage to allow explosive depressurization of the magma column. That will provide predictions of exit velocities at the vent that could be compared with estimates from plume heights and related observations.

Summers, P.; Dunham, E. M.

2013-12-01

314

33 CFR 154.828 - Vapor recovery and vapor destruction units.  

Science.gov (United States)

...2010-07-01 false Vapor recovery and vapor destruction units. 154.828 Section 154...154.828 Vapor recovery and vapor destruction units. (a) The inlet to a vapor...CG-522). (b) The inlet to a vapor destruction unit must: (1) Have a liquid...

2010-07-01

315

40 CFR 796.1950 - Vapor pressure.  

Science.gov (United States)

...relatively low vapor pressures, high adsorptivity onto solids, or high solubility in water are less likely to vaporize...airborne than chemicals with high vapor pressures or with low water solubility or low adsorptivity...

2010-07-01

316

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

317

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

318

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

319

Magmatic and hydromagmatic conduit development during the 1975 Tolbachik Eruption, Kamchatka, with implications for hazards assessment at Yucca Mountain, NV  

Science.gov (United States)

Xenoliths in pyroclastic fall deposits from the 1975 Tolbachik eruption constrain the timing and development of subsurface conduits associated with basaltic cinder cone eruptions. The two largest Tolbachik vents contain xenoliths derived from magmatic and hydromagmatic processes, which can be correlated with observed styles of eruption activity. Although many basaltic eruptions progress from early hydromagmatic activity to late magmatic activity, transient hydromagmatic events occurred relatively late in the 1975 eruption sequence. Magmatic fall deposits contain 0.01-0.3 vol.% xenoliths from 500 m depth into the dry-out zone around the conduit, disrupting and ejecting 10 5-10 6 m 3 of wall-rock through hydromagmatic processes with conduits widening to 8-48 m. Hydromagmatic falls contain 60-75 vol.% of highly fragmented xenoliths, with juvenile clasts displaying obvious magma-water interaction features. During the largest hydromagmatic event, unusual breccia-bombs formed containing a wide range of fresh and pyrometamorphic xenoliths suspended in a quenched basaltic matrix. Hydromagmatic activity during the 1975 Tolbachik eruption occurred below likely fragmentation depths for a basalt containing 2.2 wt.% magmatic water. This activity is more likely related to conduit-wall collapse rather than variations in conduit-flow pressure. In contrast, larger volume silicic eruptions may have transient hydromagmatic events in response to conduit flow dynamics above the magma fragmentation depth. The 1975 Tolbachik volcanoes are reasonably analogous to Quaternary basaltic volcanoes in the Yucca Mountain region and can guide interpretations of their poorly preserved deposits. The youngest basaltic volcanoes near Yucca Mountain have cone deposits characterized by elevated xenolith abundances and distinctive xenolith breccia-bombs, remarkably similar to 1975 Tolbachik deposits. Extrapolation of 1975 Tolbachik data suggests conduits for some Yucca Mountain basaltic volcanoes may have widened locally on the order of 50 m in response to late-stage hydromagmatic events.

Doubik, Philip; Hill, Brittain E.

1999-07-01

320

A comparison of the performance of mono- and bi-component electrospun conduits in a rat sciatic model.  

Science.gov (United States)

Synthetic nerve conduits represent a promising strategy to enhance functional recovery in peripheral nerve injury repair. However, the efficiency of synthetic nerve conduits is often compromised by the lack of molecular factors to create an enriched microenvironment for nerve regeneration. Here, we investigate the in vivo response of mono (MC) and bi-component (BC) fibrous conduits obtained by processing via electrospinning poly(?-caprolactone) (PCL) and gelatin solutions. In vitro studies demonstrate that the inclusion of gelatin leads to uniform electrospun fiber size and positively influences the response of Dorsal Root Ganglia (DRGs) neurons as confirmed by the preferential extensions of neurites from DRG bodies. This behavior can be attributed to gelatin as a bioactive cue for the cultured DRG and to the reduced fibers size. However, in vivo studies in rat sciatic nerve defect model show an opposite response: MC conduits stimulate superior nerve regeneration than gelatin containing PCL conduits as confirmed by electrophysiology, muscle weight and histology. The G-ratio, 0.71 ± 0.07 for MC and 0.66 ± 0.05 for autograft, is close to 0.6, the value measured in healthy nerves. In contrast, BC implants elicited a strong host response and infiltrating tissue occluded the conduits preventing the formation of myelinated axons. Therefore, although gelatin promotes in vitro nerve regeneration, we conclude that bi-component electrospun conduits are not satisfactory in vivo due to intrinsic limits to their mechanical performance and degradation kinetics, which are essential to peripheral nerve regeneration in vivo. PMID:25085857

Cirillo, Valentina; Clements, Basak A; Guarino, Vincenzo; Bushman, Jared; Kohn, Joachim; Ambrosio, Luigi

2014-10-01

 
 
 
 
321

Comment faire parler les images aux rayons X du conduit vocal  

Directory of Open Access Journals (Sweden)

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

Laprie Yves

2014-07-01

322

Troubles des conduites alimentaires et tempérament cyclothymique: étude transversale à propos de 107 étudiants Tunisiens  

Science.gov (United States)

Introduction Les objectifs de notre étude ont été d'estimer la prévalence des troubles des conduites alimentaires (TCA) chez les jeunes tunisiens et étudier la relation entre le tempérament cyclothymique et les TCA. Méthodes Nous avons ainsi mené une étude transversale descriptive et analytique. Elle a concerné 107 étudiants de l'Institut de Presse et des Sciences de l'Information de la Manouba, Tunisie. Pour l’évaluation des TCA, nous avons procédé par la passation de l'auto questionnaire EAT 40, dans sa version validée en Tunisie. C'est l'outil le plus utilisé pour le dépistage des TCA dans le monde. Pour l’évaluation du tempérament cyclothymique, nous avons utilisé le TEMPS A dans sa version arabe validée. Une fiche épidémiologique associée a permis de recueillir quelques facteurs sociodémographiques et hygiéno-diététiques. Résultats La prévalence des troubles de conduites alimentaires a été de 24,3%. Le pourcentage des étudiants ayant un score de tempérament cyclothymique ?14 a été de 37,4%. Une association a été trouvée entre les troubles de conduites alimentaires et le tempérament affectif cyclothymique que ce soit selon l'approche dimensionnelle (p=0,005) ou selon celle catégorielle (p=0,046). Le tempérament cyclothymique multiplie par deux le risque de développer un TCA chez les étudiants de sexe féminin (p=0,04). Conclusion Es TCA sont fréquents chez nos étudiants particulièrement de sexe féminin. De plus, la présence d'un tempérament cyclothymique associé permettrait de suspecter doublement une appartenance au spectre bipolaire et devrait conduire à une attention particulière de la part du clinicien pour définir au mieux les stratégies thérapeutiques. PMID:25404977

Jaweher, Masmoudi; Sonda, Trabelsi; Uta, Ouali; Inès, Feki; Rim, Sallemi; Imene, Baati; Abdelaziz, Jaoua

2014-01-01

323

Drain-back process of basaltic magma in the summit conduit detected by microgravity observation at Izu-Oshima Volcano, Japan  

Science.gov (United States)

Basalt magma sometimes moves through volcanic conduits causing only minor deformation. In that case, we may detect magma movements directly by microgravity observations. After the 1986 eruption of Izu-Oshima volcano, we observed anomalous gravity variations localized at the summit. Based on a vertical cylindrical conduit model, we estimate the time variations of the head of magma in the summit conduit and clarify the magma drain-back process after the 1986 eruption.

Watanabe, Hidefumi; Okubo, Shuhei; Sakashita, Shikou; Maekawa, Tokumitsu

324

Eddy transport of water vapor in the Martian atmosphere  

Science.gov (United States)

Viking orbiter measurements of the Martian atmosphere suggest that the residual north polar water-ice cap is the primary source of atmospheric water vapor, which appears at successively lower northern latitudes as the summer season progresses. Zonally symmetric studies of water vapor transport indicate that the zonal mean meridional circulation is incapable of transporting from north polar regions to low latitudes the quantity of water vapor observed. This result has been interpreted as implying the presence of nonpolar sources of water. Another possibility is the ability of atmospheric wave motions, which are not accounted for in a zonally symmetric framework, to efficiently accomplish the transport from a north polar source to the entirety of the Northern Hemisphere. The ability or inability of the full range of atmospheric motions to accomplish this transport has important implications regarding the questions of water sources and sinks on Mars: if the full spectrum of atmospheric motions proves to be incapable of accomplishing the transport, it strengthens arguments in favor of additional water sources. Preliminary results from a three dimensional atmospheric dynamical/water vapor transport numerical model are presented. The model accounts for the physics of a subliming water-ice cap, but does not yet incorporate recondensation of this sublimed water. Transport of vapor away from this water-ice cap in this three dimensional framework is compared with previously obtained zonally symmetric (two dimensional) results to quantify effects of water vapor transport by atmospheric eddies.

Murphy, J. R.; Haberle, Robert M.

1993-01-01

325

Surface reaction of titanium beryllide with water vapor  

International Nuclear Information System (INIS)

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

326

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

Energy Technology Data Exchange (ETDEWEB)

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.

Martovetsky, N N

2003-04-14

327

Réalité augmentée pour l'aide à la conduite intégrant l'observation du conducteur  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cet article présente un travail de recherche qui a permis d'aboutir à la réalisation d'un système d'aide à la conduite par la réalité augmentée : DAARIA (Driver Assistance by Augmented Reality for Intelligent Automotive). Via une métaphore de visualisation adaptée, il restitue la position des obstacles et quantifie leur dangerosité. L'originalité de la solution proposée vient de l'intégration du comportement du conducteur dans le calcul du taux de danger d'un obstacle. Le conduc...

George, Paul; Thouvenin, Indira; Fremont, Vincent; Cherfaoui, Ve?ronique

2011-01-01

328

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

329

Meso-Rex shunt using deep femoral vein conduit: first report.  

Science.gov (United States)

The Meso-Rex shunt (MRS) procedure was first described in 1992 by de VILLE et al. for the treatment of extrahepatic portal vein obstruction (EHPVO) in paediatric liver transplant patients. This technique provides more physiological relief of portal hypertension compared to the porto-systemic shunts, which can lead to long-term complications such as hyperammonaemia and hepato-pulmonary syndrome. Different conduits as autologous and cryopreserved veins or prosthetic grafts have been previously reported. We present herein the first case of a MRS using the autologous deep femoral vein in a 17-year-old female patient affected by EHPVO from unknown reasons. PMID:24294806

Sebastiani, S; Martens, T; Randon, C; de Jaeger, A; De Bruyne, R; Voet, D; Troisi, R I

2013-01-01

330

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

Energy Technology Data Exchange (ETDEWEB)

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.

Obana, Tetsuhiro [National Institute for Fusion Science, Toki (Japan)], E-mail: obana.tetsuhiro@LHD.nifs.ac.jp; Takahata, Kazuya; Hamaguchi, Shinji; Yanagi, Nagato; Mito, Toshiyuki; Imagawa, Shinsaku [National Institute for Fusion Science, Toki (Japan); Kizu, Kaname; Tsuchiya, Katsuhiko; Hoshi, Ryo; Yoshida, Kiyoshi [Japan Atomic Energy Agency, Naka (Japan)

2009-06-15

331

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

332

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

333

Tubing For Sampling Hydrazine Vapor  

Science.gov (United States)

Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

1993-01-01

334

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

335

Vapor deposition of hardened niobium  

Science.gov (United States)

A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)

1983-04-19

336

Packed Alumina Absorbs Hypergolic Vapors  

Science.gov (United States)

Beds of activated alumina effective as filters to remove hypergolic vapors from gas streams. Beds absorb such substances as nitrogen oxides and hydrazines and may also absorb acetylene, ethylene, hydrogen sulfide, benzene, butadiene, butene, styrene, toluene, and xoylene. Bed has no moving parts such as pumps, blowers and mixers. Reliable and energy-conservative. Bed readily adapted to any size from small portable units for use where little vapor release is expected to large stationary units for extensive transfer operations.

Thomas, J. J.; Mauro, D. M.

1984-01-01

337

Experimental study on scale removal from special-shaped conduits through underwater electrical discharge  

International Nuclear Information System (INIS)

Underwater electrical discharge technology is an innovative technique that can be used to enhance the stress intensity of water and improve the load addition. The technique enlarges the section area and compresses the surrounding water using a high-powered shock wave, which is induced by an underwater electrical discharge. This paper investigates the effectiveness of scale removal for special-shaped conduits employing underwater electrical discharge. Experimental results show that the pressure wave generated by underwater electrical discharge is capable of eliminating scale in special-shaped conduits. The data indicates that when the capacitance of the parallel-pulsed capacitors was 4 ?F, the high pulsed power voltage was 33 kV and the primary discharge gap was 48 mm, the result of scale removal was remarkable. In laboratory tests, the scale of special equipment was removed to a great extent by this method. Because of its effectiveness and low cost, this method improves the practice and extends the lifetime of such equipment, and thus has potential application and economic value.

338

Experimental study on scale removal from special-shaped conduits through underwater electrical discharge  

Science.gov (United States)

Underwater electrical discharge technology is an innovative technique that can be used to enhance the stress intensity of water and improve the load addition. The technique enlarges the section area and compresses the surrounding water using a high-powered shock wave, which is induced by an underwater electrical discharge. This paper investigates the effectiveness of scale removal for special-shaped conduits employing underwater electrical discharge. Experimental results show that the pressure wave generated by underwater electrical discharge is capable of eliminating scale in special-shaped conduits. The data indicates that when the capacitance of the parallel-pulsed capacitors was 4 ?F, the high pulsed power voltage was 33 kV and the primary discharge gap was 48 mm, the result of scale removal was remarkable. In laboratory tests, the scale of special equipment was removed to a great extent by this method. Because of its effectiveness and low cost, this method improves the practice and extends the lifetime of such equipment, and thus has potential application and economic value.

Cao, Y.; Wang, Z. Q.; Li, G. F.; Wu, Y.; Zhou, J. J.

2013-03-01

339

Age-related changes in biomechanical properties of transgenic porcine pulmonary and aortic conduits.  

Science.gov (United States)

The limitations associated with conventional valve prosthesis have led to a search for alternatives. One potential approach is tissue engineering. Most tissue engineering studies have described the biomechanical properties of heart valves derived from adult pigs. However, because one of the factors affecting the function of valve prosthesis after implantation is appropriate sizing for a given patient, it is important to evaluate the usefulness of a heart valve given the donor animal's weight and age. The aim of this study was to evaluate how the age of a pig can influence the biomechanical and hemodynamical properties of porcine heart valve prosthesis after acellularization. Acellular porcine aortic and pulmonary valve conduits were used. Hearts were harvested from animals differing in weight and age. The biomechanical properties of the valves were then characterized using a uniaxial tensile test. Moreover, computer simulations based on the finite element method (FEM) were used to study the influence of biomechanical properties on the hemodynamic conditions. Studying biomechanical and morphological changes in porcine heart valve conduits according to the weight and age of the animals can be valuable for developing age-targeted therapy using tissue engineering techniques. PMID:25198579

Wilczek, Piotr; Malota, Zbigniew; Lesiak, Anna; Niemiec-Cyganek, Aleksandra; Kubin, Barbara; Slomski, Ryszard; Nozynski, Jerzy; Wilczek, Grazyna; Mzyk, Aldona; Gramatyka, Michalina; Opiela, Jolanta

2014-10-01

340

Multiwalled CNT-pHEMA composite conduit for peripheral nerve repair.  

Science.gov (United States)

A nerve conduit is designed to improve peripheral nerve regeneration by providing guidance to the nerve cells. Conductivity of such guides is reported to enhance this process. In the current study, a nerve guide was constructed from poly(2-hydroxyethyl methacrylate) (pHEMA), which was loaded with multiwalled carbon nanotubes (mwCNT) to introduce conductivity. PHEMA hydrogels were designed to have a porous structure to facilitate the transportation of the compounds needed for cell nutrition and growth and also for waste removal. We showed that when loaded with relatively high concentrations of mwCNTs (6%, w/w in hydrogels), the pHEMA guide was more conductive and more hydrophobic than pristine pHEMA hydrogel. The mechanical properties of the composites were better when they carried mwCNT. Elastic modulus of 6% mwCNT loaded pHEMA was twofold higher (0.32 ± 0.06 MPa) and similar to that of the soft tissues. Electrical conductivity was significantly improved (11.4-fold) from 7 × 10(-3) ?(-1).cm(-1) (pHEMA) to 8.0 × 10(-2) ?(-1).cm(-1) (6% mwCNT loaded pHEMA). On application of electrical potential, the SHSY5Y neuroblastoma cells seeded on mwCNTs carrying pHEMA maintained their viability, whereas those on pure pHEMA could not, indicating that mwCNT helped conduct electricity and make them more suitable as nerve conduits. PMID:23554154

Arslantunali, D; Budak, G; Hasirci, V

2014-03-01

 
 
 
 
341

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

342

Excessive degassing of Izu-Oshima volcano: magma convection in a conduit  

Science.gov (United States)

Excess degassing of magmatic H2O and SO2 was observed at Izu-Oshima volcano during its latest degassing activity from January 1988 to March 1990. The minimum production rate for degassed magma was calculated to be about 1×104 kg/s using emission rates of magmatic H2O and SO2, and H2O and S contents of the magma. The minimum total volume of magma degassed during the 27-month period is estimated to be 2.6×108 m3. This volume is 20 times larger than that of the magma ejected during the 1986 summit eruption. Convective transport of magma through a conduit is proposed as the mechanism that causes degassing from a magma reservoir at several kilometers depth. The magma transport rate is quantitatively evaluated based on two fluid-dynamic models: Poiseuille flow in a concentric double-walled pipe, and ascent of non-degassed magma spheres through a conduit filled with degassed magma. This process is further tested for an andesitic volcano and is concluded to be a common process for volcanoes that discharge excess volatiles.

Kazahaya, Kohei; Shinohara, Hiroshi; Saito, Genji

1994-08-01

343

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

Directory of Open Access Journals (Sweden)

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

Sofos SS

2015-01-01

344

Neural regrowth induced by PLGA nerve conduits and neurotrophin-3 in rats with complete spinal cord transection.  

Science.gov (United States)

Biomaterials and neurotrophic factors represent two promising strategies for spinal cord injury repair. In this study, a combinatorial approach combining the PLGA nerve conduits and the recombinant human neurotrophin-3 (rhNT3) was utilized in a spinal cord injury animal model. After complete transection of the thoracic cord in rats, rhNT3 was administered as a single dose to the host cord caudal to a 2-mm conduit. Axonal regrowth was enhanced, as indicated by immunostaining and neurofilament-positive area measurement. Neural regrowth was further demonstrated via the retrograde tracing across the lesion. The animals implanted with the PLGA scaffold and rhNT3 exhibited significantly improved performance in BBB rating scale and grid walk tests. These observations suggest that PLGA nerve conduits combined with exogenous NT3 may serve as an alternative therapeutic approach for spinal cord injury repair. PMID:21384547

Fan, Juan; Zhang, Hongtian; He, Jianghong; Xiao, Zhifeng; Chen, Bing; Xiaodan, Jiang; Dai, Jianwu; Xu, Ruxiang

2011-05-01

345

controlled water vapor conditions  

Directory of Open Access Journals (Sweden)

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

M.A. V\\u00E1squez-A.

2007-01-01

346

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.se made of PTFE seen in other studies.

347

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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'arracha...

Line A.; Masbernat L.

2006-01-01

348

The atmospheric water vapor line.  

Science.gov (United States)

We have measured the hydrogen and oxygen isotope composition of atmospheric water vapor periodically across the American Southwest through most of 2007. Samples were primarily collected over Albuquerque, NM on the roof of the 3-story UNM geology building on a near-daily basis with occasional sampling in southern Arizona and southern Texas. Water vapor was captured by pumping ~60 to ~600 liters of air (amount depending on dew point) through a cold trap, producing ~1mL of water. Precipitation samples were also collected in Albuquerque throughout the year and analyzed for hydrogen and oxygen isotopic composition. Isotopic compositions of both vapor and precipitation were determined by CO2 equilibration for oxygen and chromium reduction for hydrogen, with resulting gasses analyzed on a mass spectrometer. Nearly all water vapor samples lie parallel to the Global Meteoric Water Line (GMWL) but with a deuterium excess of ~17 (?D = 8?O + 17). This is true regardless of relative humidity, dew point, location, time of day, or season. Precipitation samples fall to the right of the GMWL with a slope of ~5. Within our dataset we have identified 10 pairs of vapor and precipitation samples that were collected within 24 hours. Half of these sample pairs have values consistent with equilibrium conditions at ground temperature, while the other half are not in equilibrium at any temperature. Simple modeling of nonequilibrium fractionation processes suggests that the array of precipitation samples can be derived from the array of vapor samples by equilibrium condensation followed by partial evaporation of falling raindrops. Our data suggests that atmospheric water vapor has a relatively constant deuterium excess value regardless of moisture source, degree of rainout, and/or evapotranspiration contributions.

Strong, M.; Sharp, Z. D.; Gutzler, D. S.

2008-12-01

349

Development of a polysilicon process based on chemical vapor deposition (phase 1)  

Science.gov (United States)

A dichlorosilane-based reductive chemical vapor deposition (CVD) process demonstrated is capable of producing, at low cost, high quality polycrystalline silicon. Testing of decomposition reactor heat shields to insure that the shield provides adequate personnel protection assuming a worst case explosion was completed. Minor modifications to a production reactor heat shield provided adequate heat shield integrity. Construction of the redesigned PDU (Process Development Unit) to accommodate all safety related information proceeded on schedule. Structural steel work was completed as is the piping and instrumentation design work. Major pieces of process equipment were received and positioned in the support structure and all transfer piping and conduits to the PDU were installed. Construction was completed on a feed system for supplying DCS to an intermediate sized reactor. The feed system was successfully interfaced with a reactor equipped with a modified heat shield. Reactor checkout was completed.

McCormick, J.; Arvidson, A.; Sawyer, D.; Plahutnik, F.

1981-06-01

350

Melt and vapor characteristics in an electron beam evaporator  

International Nuclear Information System (INIS)

Two different approaches have been compared for the calculation of the free surface temperature Ts in cerium or copper evaporation experiments: the first method considers properties of the melt: an empirical law is used to take into account turbulent thermal convection, instabilities and characterization of the free surface. The second method considers the vapor flow expansion and connects Ts to the measured terminal temperature and 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 characterization 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 Ts and the Knudsen number at the vapour source reach a threshold when the beam power increases. (author). 12 figs., 1 tab., 21 refs

351

An opacity-sampled treatment of water vapor  

Science.gov (United States)

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

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

1989-01-01

352

Raman lidar water vapor measurements performed at CNR-IMAA  

Science.gov (United States)

A Raman lidar system for water vapor measurements is operational at Istituto di Metodologie per l'Analisi Ambientale (IMAA),in Tito Scalo, Potenza, (Southern Italy, 40°36'N, 15°44'E, 760 m above sea level) since July 2002. The Raman technique is widely employed for tropospheric water vapor measurements with high vertical and temporal resolution. In principle, Raman lidar measurement of water vapor can be calibrated in absolute terms, but present uncertainties in the ratio of Raman lidar cross section of water vapor and nitrogen limit this calibration accuracy to about 10%. In order to obtain good accuracy, the Raman lidar water vapor measurements are typically calibrated to independent water vapor measurements. In May-June 2002, an intensive measurement campaign was performed at CNR-IMAA in order to calibrate the IMAA Raman lidar system for water vapor profiling by means of contemporary and co-located Vaisala RS80-A radiosondes measurements. The radiosonde data have been corrected for temperature dependence error and for dry bias due to chemical contamination error. Moreover, from July 2002 more than 100 lidar and radiosonde simultaneous measurements have been performed and have been used to check the stability of the lidar calibration constant, that remains within 5%. Since February 2004, a 12 channels microwave radiometer is operative at CNR-IMAA, providing temperature, relative humidity and liquid water profiles up to 10 km of altitude, and the integrated precipitable water vapor and integrated liquid water measurements. Since this radiometer provides good accuracy measurements of the integrated water vapor column content, every 5 minutes, 24 hours per day, it is the best candidate for routinely check of the stability of the Raman lidar system calibration constant: the calibration constant has been checked comparing the integrated water vapor column content measured by microwave radiometer and the corresponding quantity measured by the Raman lidar, obtained integrating lidar water vapor vertical profile from the ground up to the tropopause. This allows to overall all the problems related to radiosounding water vapor measurements, like dry bias, different investigated air volumes, and high costs. The IMAA Raman lidar system is able to provide water vapor mixing ratio vertical profiles up to the tropopause in night-time and up to 5 km of altitude in daytime conditions, with a typical temporal resolution of 10 minutes. Systematic measurements have been performed in the period July 2002 - July 2003 in the framework of the validation program of ENVISAT, in order to validate MIPAS water vapor products. Moreover, after the validation campaign, systematic measurements are still in progress. Besides systematic measurements, this system has been employed in special measurements campaigns, as the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) field campaign in summer 2004 and the European AQUA Thermodynamic Experiment (EAQUATE) Italian phase in the 6-10 September 2004. In addition, in autumn 2005, the IMAA Raman lidar system for water vapor measurements will be involved in the international Lindenberg anniversary campaign for Assessment of hUmidity aNd Cloud profiling systems and its impact on High-resolution modelling (LAUNCH- 2005). ACKNOWLEDGMENTS The financial support of this work by the European Space Agency under grant ESA-ESTEC Contract No. 16040/02/NL/SF, ``Ground based observations of water vapour and aerosol for the validation of ENVISAT products'', is gratefully acknowledged.

Cornacchia, C.; Amodeo, A.; D'Amico, G.; Madonna, F.; Mona, L.; Pappalardo, G.

2005-12-01

353

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

354

Method for controlling corrosion in thermal vapor injection gases  

Energy Technology Data Exchange (ETDEWEB)

A method is described which produces a high pressure, thermal vapor stream. It is comprised of steam and combustion gases for injection into a subterranean formation, for the recovery of viscous minerals, almost totally free of corrosion-causing oxides of nitrogen and sulfur. This practice is important during the period wherein the equipment and down-hole tubing is being warmed up because some condensation of water usually occurs with attendant corrosion, even when the thermal vapor produced initially is superheated. The method involves injecting water through a specifically positioned injector means adjacent to the fuel injector nozzle into the combustion zone of the combustion chamber. It was found that the water injected lowers the interior temperature of the combustion chamber sufficient to decrease the fixation of nitrogen with oxygen without impairing the overall quality of the thermal vapor gases injected down the well bore. The combustion gases pass from the combustion chamber into a vapor producing vessel, where ammonia is injected to further neutralize the acidic oxides of nitrogen and sulfur in the high pressure thermal vapor stream. 7 claims.

Sperry, J.S.; Krajicek, R.W.

1982-08-17

355

Possible near-IR channels for remote sensing precipitable water vapor from geostationary satellite platforms  

Science.gov (United States)

Remote sensing of troposheric water vapor profiles from current geostationary weather satellites is made using a few broadband infrared (IR) channels in the 6-13 micron region. Uncertainties greater than 20% exist in derived water vapor values just above the surface from the IR emission measurements. In this paper, we propose three near-IR channels, one within the 0.94-micron water vapor band absorption region, and the other two in nearby atmospheric windows, for remote sensing of precipitable water vapor over land areas, excluding lakes and rivers, during daytime from future geostationary satellite platforms. The physical principles are as follows. The reflectance of most surface targets varies approximately linearly with wavelength near 1 micron. The solar radiation on the sun-surface-sensor ray path is attenuated by atmospheric water vapor. The ratio of the radiance from the absorption channel with the radiances from the two window channels removes the surface reflectance effects and yields approximately the mean atmospheric water vapor transmittance of the absorption channel. The integrated water vapor amount from ground to space can be obtained with a precision of better than 5% from the mean transmittance. Because surface reflectances vary slowly with time, temporal variation of precipitable water vapor can be determined reliably. High spatial resolution, precipitable water vapor images are derived from spectral data collected by the Airborne Visable-Infrared Imaging Spectrometer, which measures solar radiation reflected by the surface in the 0.4-2.5 micron region in 10-nm channels and has a ground instantaneous field of view of 20 m from its platform on an ER-2 aircraft at 20 km. The proposed near-IR reflectance technique would complement the IR emission techniques for remote sensing of water vapor profiles from geostationary satellite platforms, especially in the boundary layer where most of the water vapor is located.

Gao, B.-C.; Goetz, A. F. H.; Westwater, Ed R.; Conel, J. E.; Green, R. O.

1993-01-01

356

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

Energy Technology Data Exchange (ETDEWEB)

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.

Dresner, L.

1980-01-01

357

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

358

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

359

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

360

CFD Modeling of ITER Cable-in-Conduit Superconductors. Part I: Friction in the Central Channel  

International Nuclear Information System (INIS)

In this paper, the first of a series, we propose a novel approach, based on Computational Fluid Dynamics (CFD), to understand the complex transverse thermal-hydraulic processes in the dual-channel cable-in-conduit conductors (CICC), which are used for the superconducting magnets of the International Thermonuclear Experimental Reactor (ITER). Advanced 2D and 3D CFD, including sophisticated turbulence models, is used to compute the mass flow rate corresponding to an imposed pressure drop in rib-roughened pipes, including spirals mimicking the central channel of an ITER CICC and used in several experiments. The results of the calculation are validated against measured data and can be used to deduce the friction factor fH in the central channel, throwing at the same time some light on the role played by the different parameters (Reynolds number, spiral geometry, etc.) in the central channel friction process for an ITER CICC

 
 
 
 
361

CFD Modeling of ITER Cable-in-Conduit Superconductors. Part I: Friction in the Central Channel  

Science.gov (United States)

In this paper, the first of a series, we propose a novel approach, based on Computational Fluid Dynamics (CFD), to understand the complex transverse thermal-hydraulic processes in the dual-channel cable-in-conduit conductors (CICC), which are used for the superconducting magnets of the International Thermonuclear Experimental Reactor (ITER). Advanced 2D and 3D CFD, including sophisticated turbulence models, is used to compute the mass flow rate corresponding to an imposed pressure drop in rib-roughened pipes, including spirals mimicking the central channel of an ITER CICC and used in several experiments. The results of the calculation are validated against measured data and can be used to deduce the friction factor fH in the central channel, throwing at the same time some light on the role played by the different parameters (Reynolds number, spiral geometry, etc.) in the central channel friction process for an ITER CICC.

Zanino, R.; Giors, S.; Mondino, R.

2006-04-01

362

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

Science.gov (United States)

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. PMID:23345956

Sa, Young Jo; Kim, Young Du; Kim, Chi Kyung; Park, Jong Kyung; Moon, Seok Whan

2013-01-14

363

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

364

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

365

Understanding conduit dynamics and forecasting major strombolian explosions by ground-based radar interferometry  

Science.gov (United States)

Volcanic eruptions are preceded by a series of detectable phenomena related to: i) rise of magma and gas from deep, dike-filling intrusions, ii) increase in magma pressures within conduits, iii) inflation of volcanic edifices.. Ground deformation resulting from volcano inflation can be recorded by various techniques as the recent ground-based radar interferometry (GB-InSAR). Here we present GB-InSAR deformation data (interferograms) collected at Stromboli volcano (Aeolian Islands, Southern Italy) over the period 2008-2011 to evidence that increase in deformation rate in the upper portion of the conduit system occurred before the onset of the very hazardous, "non-forecastable" "major" explosions. "Major" explosions are high-intensity "variation on the Strombolian theme" and, until now, little precursors have been identified. At Stromboli they often occurr clustered within a short time period characterized by "anomalous" activity, that we define as "major-explosions dominated" period. During this phase, the enhanced explosive activity is often associated with lava emissions from the summit craters, and "ordinary" Strombolian activity appears more vigorous and frequent. Medium, short and very-short term interferograms of the summit crater area of Stromboli,revealed increased patterns of deformation rate of the vent areas prior the onset of major explosions. Both the base and the rim of the craters area are the involved in the deformation, with different timing before the occurrence of major explosive events. At the base of the crater, corresponding to the intersection of the summit area with the northern tip of the NE-SW trending dike-conduit, an increase in deformation rate is observed, starting from one week to one month before the onset of a major-explosions dominated period., At the crater rim an increase from high to very high deformation rate is shown about ten to twenty minutes and twenty to forty seconds before each major explosion. We propose that the deformation patterns observed at the base of the summit area is associated to an upward compression in the area below the vent induced by the ascent of a volatile-rich, low-porphyritic, deeper magma, pushing the degassed, higly porphyritic magma residing in the upper portion of the magma column. We believe that a batch of more-deeply seated, uprising magma promotes the onset of the high-intensity, MED activity. On the other side, the pattern observed at the craters rim can be explained by pressurization of the upper conduit due to gas-slug expansion prior and coeval with the major explosions. Our results suggest that continuous GB-InSAR volcano monitoring could prove insightful if applied to the study of crater areas, and hence to improve forecasting capabilities of high-intensity explosions at Stromboli and other "moderate-explosive" volcanic systems.

Di Traglia, F.; Del Ventisette, C.; Rosi, M.; Mugnai, F.; Intrieri, E.; Moretti, S.; Casagli, N.

2012-04-01

366

SOME NATURAL CONDUIT ANALOGUES FOR POTENTIAL IGNEOUS ACTIVITY AT YUCCA MOUNTAIN  

Energy Technology Data Exchange (ETDEWEB)

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 ({approx}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 {approx}2.6 Ma alkali basaltic volcano with a chain of 2-3 vents that fed {approx}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 {approx}125 m, including 40 m beneath the paleosurface, and has a relatively constant width of {approx}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 {approx}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 {approx}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 {approx}100 m x 70 m in map view but inclusion of the mixed zone increases this to {approx}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 {approx}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.

D.J. Krier; G.N. Keating; G.A. Valentine

2005-08-26

367

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

368

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

369

Failing left ventricle to ascending aorta conduit-Hybrid implantation of a melody valve and NuMed covered stent.  

Science.gov (United States)

We present the case of a 36-year-old woman with increasing shortness of breath, a new 3/4 diastolic murmur, and a complex history of LV outflow tract obstruction. She has undergone multiple surgeries including the replacement of her old LV apex to ascending aorta conduit with a 20-mm Gore-Tex tube graft, addition of a 24-mm homograft sutured between the conduit and the LV apex, and insertion of a 21-mm Freestyle porcine valve conduit between the Gore-Tex tube graft and allograft at age 23. The current assessment showed a failing Freestyle conduit prosthesis leading to left heart decompensation. Due to substantial surgical risk, the patient underwent successful implantation of a Melody valve into the Gore-Tex tube and exclusion of the failing Freestyle bioprosthesis with a NuMed CP stent in a hybrid procedure. The case nicely illustrates the collaborative potential of cardiovascular surgeons and interventional cardiologists in the new arena of a hybrid operating room. Complex hybrid procedures like the current one, especially those including percutaneous placements of valves, offer therapeutic options for patients that are otherwise too high risk for conventional open heart surgery. PMID:23784974

Gössl, Mario; Johnson, Jonathan N; Hagler, Donald J

2014-04-01

370

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

Directory of Open Access Journals (Sweden)

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

White,W.B.

2003-01-01

371

Olfactory ensheathing cells seeded muscle-stuffed vein as nerve conduit for peripheral nerve repair: a nerve conduction study.  

Science.gov (United States)

We evaluated bridging of 15 mm nerve gap in rat sciatic nerve injury model with muscle-stuffed vein seeded with olfactory ensheathing cells as a substitute for nerve autograft. Neurophysiological recovery, as assessed by electrophysiological analysis was faster in the constructed biological nerve conduit compared to that of autograft. PMID:24598302

Lokanathan, Yogeswaran; Ng, Min-Hwei; Hasan, Shariful; Ali, Anuar; Mahmod, Mazzre; Htwe, Ohnmar; Roohi, Sharifah Ahmad; Bt Hj Idrus, Ruszymah; Abdullah, Shalimar; Naicker, Amaramalar Selvi

2014-08-01

372

Geometrical Probability Distribution Functions for Cable-in-Conduit Conductors with Simply and Multiply Connected Cross-Sections  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A geometrical method is presented for the calculation of the strand distribution functions for cable-in-conduit superconductors with simple and multiply connected cross-sections. The method is illustrated on different cable designs with simply and multiply connected structures.

Anghel, A.

2013-01-01

373

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

International Nuclear Information System (INIS)

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

374

Volcano inflation prior to an eruption: Numerical simulations based on a 1-D magma flow model in an open conduit  

Science.gov (United States)

We numerically simulate volcanic inflation caused by magma ascent in a shallow conduit at volcanoes which repeatedly erupt, in order to understand the effect of volatile behavior on magma from geodetic data. Considering magma in which the relative velocities between melt and gas bubbles are negligible, we model magma flow in a one-dimensional open conduit with diffusive gas bubble growth. We calculate the ground displacements and tilts caused by spatio-temporal changes of magma pressure in the conduit. Our simulations show that magma without volatiles causes decelerated changes in volcanic inflation. Magma with gas bubble growth inflates the volcano with a constant, or accelerated, rate. Temporal changes of volcanic deformation are also affected by the magma pressure at the bottom of the conduit. When the pressure is small, the displacements and tilts increase in proportion to the 1.5th power of time. This time rate is similar to that predicted from a basic gas bubble growth model. When the pressure equals the lithostatic pressure, the effects of gas bubble growth relatively decrease and the displacements and tilts increase linearly with time.

Kawaguchi, R.; Nishimura, T.; Sato, H.

2013-12-01

375

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

Energy Technology Data Exchange (ETDEWEB)

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

Shajii, A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

1994-04-01

376

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

International Nuclear Information System (INIS)

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

377

Imaging of a lava dome in Unzen, Japan and a shallow conduit in Stromboli, Italy  

Science.gov (United States)

The latest lava dome in Mt. Unzen was formed in the eruption from January 1991 to early 1995 and the activity was calmed down in 1995. The researchers kept to observe the eruption in this period precisely. Some of them proposed the growth model, another person proposed different model from their data[1,2]. It is significant for the growth model and the landslide prediction to investigate the density structure in the lava dome. The observation of the lava dome density 2D map was performed by using cosmic-ray muon and muon detector in Unzen. The muon detector, nuclear emulsion films which has high position resolution and 0.85m2 effective areas, was installed in a natural cave from early December 2010 to the end of March. The developed nuclear emulsion films have been scanned by automated muon readout system. The systematic analysis of efficiency and random noise ratio estimation are performed by taking a pattern match and making a connection of muon tracks between several films. Stromboli is one of the Aeolian Islands, which is located at a volcanic arc north of Sicily Island Italy. 1.0m2 nuclear emulsion films were installed at the site which is 500m far from active volcanic conduit. The shape of volcanic conduit is critical information to the study of the dynamics of eruption. After three month exposure, the films were developed and we started to analyze them in the beginning of May 2012. We will report the results of Unzen and Stromboli.

Miyamoto, S.; Aleksandrov, A.; Bozza, C.; Consiglio, L.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Kose, U.; Lauria, A.; Montesi, C.; Naganawa, N.; Pupilli, F.; Rescigno, R.; Russo, A.; Sirignano, C.; Stellacci, S. M.; Strolin, P.; Tanaka, H.; Tioukov, V.

2012-12-01

378

The mechanisms of refilling of xylem conduits and bleeding of tall birch during spring.  

Science.gov (United States)

Seasonal variations in osmolality and components of xylem sap in tall birch trees were determined using several techniques. Xylem sap was extracted from branch and trunk sections of 58 trees using the very rapid gas bubble-based jet-discharge method. The 5-cm long wood pieces were taken at short intervals over the entire tree height. The data show that large biphasic osmolality gradients temporarily exist within the conducting xylem conduits during leaf emergence (up to 272 mosmol x kg(-1) at the apex). These gradients (arising mainly from glucose and fructose) were clearly held within the xylem conduit as demonstrated by (1)H NMR imaging of intact twigs. Refilling experiments with benzene, sucrose infusion, electron and light microscopy, as well as (1)H NMR chemical shift microimaging provided evidence that the xylem of birch represents a compartment confined by solute-reflecting barriers (radial: lipid linings/lipid bodies; axial: presumably air-filled spaces). These features allow transformation of osmolality gradients into osmotic pressure gradients. Refilling of the xylem occurs by a dual mechanism: from the base (by root pressure) and from the top (by hydrostatic pressure generated by xylem-bound osmotic pressure). The generation of osmotic pressure gradients was accompanied by bleeding. Bleeding could be observed at a height of up to 21 m. Bleeding rates measured at a given height decreased exponentially with time. Evidence is presented that the driving force for bleeding is the weight of the static water columns above the bleeding point. The pressure exerted by the water columns and the bleeding volume depend on the water-filling status of (communicating) vessels. PMID:18761499

Westhoff, M; Schneider, H; Zimmermann, D; Mimietz, S; Stinzing, A; Wegner, L H; Kaiser, W; Krohne, G; Shirley, St; Jakob, P; Bamberg, E; Bentrup, F-W; Zimmermann, U

2008-09-01

379

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

Science.gov (United States)

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

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

1998-01-01

380

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

Directory of Open Access Journals (Sweden)

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

G. G. J. Ernst

2005-06-01

 
 
 
 
381

Emprego de condutos de pericárdio bovino na conexão ventrículo-arterial pulmonar: resultados tardios / Late results with the use of a valved conduit ot bovine pericardium for ventricle to pulmonary artery connection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A reconstrução biventricuiar de uma série de cardiopatias congênitas requer a interposição de condutos valvados ventrículo-arteriais. Com o objetivo de analisar a evolução a longo prazo de um conduto de pericárdio bovino valvulado com bíoprótese porcina sem suporte tratado com glutaraldeído, foram r [...] evistos os prontuários de 33 pacientes operados de novembro de 1985 a outubro de 1995. A idade variou de 15 dias a 18 anos (média 5,7 ± 4,3 anos). A atresia pulmonar com comunicação interventricular (CIV) foi a lesão mais freqüente (16 casos), seguida da síndrome da valva pulmonar ausente (5), truncus arteriosus (4), transposição das grandes artérias com CIV e estenose pulmonar (3) e outras (5). A mortalidade imediata foi de 18,2%, diretamente relacionada à condição pré-operatória. Vinte e três (70%) pacientes foram acompanhados por períodos que variaram de 3 meses a 10 anos (média 4,8 ± 3,0 anos). A complicação mais freqüentemente observada no seguimento tardio foi a estenose da anastomose distai do conduto, presente em 17,4% (4/23) dos pacientes. Foram reoperados 3 (13%) pacientes, sendo que 2 deles por estenose distal (p=0,02) e 1 por endocardite tardia do conduto. A mortalidade tardia foi de 17,4% (4/23), em 1 caso devido a estenose distai. A causa da estenose distal parece ser devida a retração tecidual na área de transição entre o pericárdio bovino e o tronco pulmonar. Em até 10 anos de seguimento não ocorreu calcificação significativa que prejudicasse a função tanto da valva quanto do conduto. Em conclusão, os condutos de pericárdio bovino apresentaram uma performance satisfatória como substitutos vasculares, não tendo ocorrido calcificação significativa da valva porcina ou das paredes do conduto no seguimento tardio. A incidência de estenose na anastomose distal parece estar mais relacionada a um fenômeno de retração tecidual do que a problemas técnicos. Abstract in english The biventricular repair of congenital heart diseases with an inadequate or absent ventricle to pulmonary artery connection sometimes requires the use of extracardiac conduits. In order to study the longterm outcome of a glutaraldehyde-preserved bovine pericardial conduit valved with a stentless por [...] cine aortic valve, we reviewed the data of 33 patients operated between November 1985 and October 1995. Patients ages ranged from 15 days to 18 years (mean 5.7 ± 4.3 years). Pulmonary atresia with ventricular septal defect (VSD) was the most frequent disease (16 cases), followed by tetralogy of Fallot with absent pulmonary valve (5), truncus arteriosus (4), transposition of great arteries with VSD and pulmonary stenosis (3) and other miscellaneous (5). The overall hospital mortality was 18.2% and was related to the preoperative clinical condition; 23 patients (70%) were followed by a mean of 4.8 ± 3.0 years (ranging from 3 months to 10 years). The most common late complication observed was stenosis of the anastomosis between the conduit and the pulmonary artery present in 17.4% (4/23) of the patients and was the cause of 2 later reoperations (p=0,02); another patient was reoperated for late conduit endocarditis. This complication was also the cause of 1 of the 4 late deaths (17.4%). The last patient is waiting for surgery. The development of the anastomotic stenosis was problably due to a retraction of the pericardial tissue along the transition with the thin wall of the pulmonary artery. Up to 10 years, gross calcification impairing the function of the valve or the conduit itself could not be detected. In conclusion, the bovine pericardial conduits have shown a good performance as a vascular substitute. Calcification has not been a major drawback. The righ incidence of distal stenosis appears to be more related to a shrinking of the pericardial tissue than to technical reasons.

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

1996-09-01

382

Emprego de condutos de pericárdio bovino na conexão ventrículo-arterial pulmonar: resultados tardios Late results with the use of a valved conduit ot bovine pericardium for ventricle to pulmonary artery connection  

Directory of Open Access Journals (Sweden)

Full Text Available A reconstrução biventricuiar de uma série de cardiopatias congênitas requer a interposição de condutos valvados ventrículo-arteriais. Com o objetivo de analisar a evolução a longo prazo de um conduto de pericárdio bovino valvulado com bíoprótese porcina sem suporte tratado com glutaraldeído, foram revistos os prontuários de 33 pacientes operados de novembro de 1985 a outubro de 1995. A idade variou de 15 dias a 18 anos (média 5,7 ± 4,3 anos. A atresia pulmonar com comunicação interventricular (CIV foi a lesão mais freqüente (16 casos, seguida da síndrome da valva pulmonar ausente (5, truncus arteriosus (4, transposição das grandes artérias com CIV e estenose pulmonar (3 e outras (5. A mortalidade imediata foi de 18,2%, diretamente relacionada à condição pré-operatória. Vinte e três (70% pacientes foram acompanhados por períodos que variaram de 3 meses a 10 anos (média 4,8 ± 3,0 anos. A complicação mais freqüentemente observada no seguimento tardio foi a estenose da anastomose distai do conduto, presente em 17,4% (4/23 dos pacientes. Foram reoperados 3 (13% pacientes, sendo que 2 deles por estenose distal (p=0,02 e 1 por endocardite tardia do conduto. A mortalidade tardia foi de 17,4% (4/23, em 1 caso devido a estenose distai. A causa da estenose distal parece ser devida a retração tecidual na área de transição entre o pericárdio bovino e o tronco pulmonar. Em até 10 anos de seguimento não ocorreu calcificação significativa que prejudicasse a função tanto da valva quanto do conduto. Em conclusão, os condutos de pericárdio bovino apresentaram uma performance satisfatória como substitutos vasculares, não tendo ocorrido calcificação significativa da valva porcina ou das paredes do conduto no seguimento tardio. A incidência de estenose na anastomose distal parece estar mais relacionada a um fenômeno de retração tecidual do que a problemas técnicos.The biventricular repair of congenital heart diseases with an inadequate or absent ventricle to pulmonary artery connection sometimes requires the use of extracardiac conduits. In order to study the longterm outcome of a glutaraldehyde-preserved bovine pericardial conduit valved with a stentless porcine aortic valve, we reviewed the data of 33 patients operated between November 1985 and October 1995. Patients ages ranged from 15 days to 18 years (mean 5.7 ± 4.3 years. Pulmonary atresia with ventricular septal defect (VSD was the most frequent disease (16 cases, followed by tetralogy of Fallot with absent pulmonary valve (5, truncus arteriosus (4, transposition of great arteries with VSD and pulmonary stenosis (3 and other miscellaneous (5. The overall hospital mortality was 18.2% and was related to the preoperative clinical condition; 23 patients (70% were followed by a mean of 4.8 ± 3.0 years (ranging from 3 months to 10 years. The most common late complication observed was stenosis of the anastomosis between the conduit and the pulmonary artery present in 17.4% (4/23 of the patients and was the cause of 2 later reoperations (p=0,02; another patient was reoperated for late conduit endocarditis. This complication was also the cause of 1 of the 4 late deaths (17.4%. The last patient is waiting for surgery. The development of the anastomotic stenosis was problably due to a retraction of the pericardial tissue along the transition with the thin wall of the pulmonary artery. Up to 10 years, gross calcification impairing the function of the valve or the conduit itself could not be detected. In conclusion, the bovine pericardial conduits have shown a good performance as a vascular substitute. Calcification has not been a major drawback. The righ incidence of distal stenosis appears to be more related to a shrinking of the pericardial tissue than to technical reasons.

Fernando Antônio Fantini

1996-09-01

383

Dynamics within geyser conduits: Insights from downhole measurements in El Jefe geyser, El Tatio Geyser Field, Chile  

Science.gov (United States)

The El Tatio geothermal area is located in the Atacama Desert at an elevation of 4200 m asl. It is the third largest geyser field in the world, with more than 100 active geysers. Recharge of meteoric waters from the NE is limited, and temperatures vary daily from -5 to 10 C. We studied a geyser that we named 'El Jefe' (601768 E, 7530174 S, WGS84 19S). Its conduit has a constriction at a depth of 1.5 m and its diameter is 30 cm. Erupted water ponds in a natural pool around the conduit, and a large fraction then flows back into to the conduit at the end of the eruption. To quantify the mechanics and thermodynamics of the geyser's eruptions, we measured temperature, and pressure continuously inside the geyser conduit for 7 days. Pressure was measured at three depths at a frequency of 100 Hz and temperature was measured at depth intervals of 30 cm at a frequency of 1Hz. During the period of our study, eruption duration was 25 +/- 1.5 seconds and the interval between eruptions was 132 +/-2.5 sec. Variations of the eruption duration and intervals did not correlate with atmospheric pressure and temperature variations. The eruption cycle consists of four distinct stages: (1) Pre-play: lasts for 15 seconds prior to the surface manifestation of the eruption. (2) Eruption: lasts for 25 seconds (3) Post-eruption relaxation: pressure decreases rapidly in two steps, but temperature decreases gradually lagging behind the pressure decrease. Erupted water is drained into the conduit. (4) Recharge: temperature remains nearly constant while pressure increases, suggesting recharge of cold water from below.

Munoz Saez, C.; Manga, M.; Hurwitz, S.; Rudolph, M. L.; Namiki, A.; Wang, C.; King, E.; Patel, A.

2013-12-01

384

Waste Tank Vapor Project: Tank vapor database development  

International Nuclear Information System (INIS)

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

385

INDOOR AIR VAPOR INTRUSION SEMINAR  

Science.gov (United States)

This seminar is sponsored by the ORD in collaboration with the Office of Solid Waste and Emergency Response. The goal of this seminar is to present information and guidance to evaluate, assess and characterize chemical vapor pathways migrating into structures resulting from conta...

386

Vapor generating unit blowdown arrangement  

International Nuclear Information System (INIS)

A vapor generating unit having a U-shaped tube bundle is provided with an orificed downcomer shroud and a fluid flow distribution plate between the lower hot and cold leg regions to promote fluid entrained sediment deposition in proximity to an apertured blowdown pipe

387

Simple Chemical Vapor Deposition Experiment  

Science.gov (United States)

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

Pedersen, Henrik

2014-01-01

388

Regional variation of the tropical water vapor and lapse rate feedbacks  

Science.gov (United States)

The global and tropical mean water vapor and lapse rate radiative feedbacks are anticorrelated across contemporary climate models. Hence, despite substantial uncertainty in both, uncertainty in total clear-sky modeled radiative feedback is small compared with other sources of feedback spread. Previous work has demonstrated that no such correlation exists when grid point water vapor and lapse rate feedbacks are considered within one model. Here we show that robust physical processes nevertheless determine significant aspects of both the water vapor and particularly the lapse rate feedbacks within the tropics. The lapse rate feedback increases with surface temperature change because the tropical troposphere cannot maintain strong temperature gradients. The water vapor feedback increases weakly with surface temperature over tropical ocean but slightly decreases over land, associated with moisture availability. Water vapor feedback is more strongly related to precipitation changes, increasing most strongly in the heaviest precipitating regions and least in the weakest.

Lambert, F. Hugo; Taylor, Patrick C.

2014-11-01

389

Boiler for generating high quality vapor  

Science.gov (United States)

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

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

1972-01-01

390

Modeling spatially and temporally varied hydraulic behavior of a folded karst system with dominant conduit drainage at catchment scale, Hochifen-Gottesacker, Alps  

Science.gov (United States)

Karst aquifers are important for freshwater supply, but difficult to manage, due to highly variable water levels and spring discharge rates. Conduits are crucial for groundwater flow in karst aquifers, but their location is often unknown, thus limiting the applicability and validity of numerical models. We have applied a conduit model (SWMM) to simulate highly variable flow in a folded alpine karst aquifer system, where the underground drainage pattern is comparatively well-known from previous tracer studies. The conduit model was coupled with a reservoir model representing recharge, storage and transfer of water in the epikarst and unsaturated zone. The global optimization approach (GA) was applied to achieve an efficient model calibration. It was possible to simultaneously simulate the highly variable discharge characteristics of an estavelle, and overflow spring and a permanent spring draining the conduit system. The model allowed for the collection of spatially differentiated information on recharge, rapid flow and slow flow in four individual sub-catchments. The formation of backwater upgradient from conduit restrictions turned out to be a key process in activating overflow springs. The proposed modeling approach appears to be transferrable to other karst systems with predominant conduit drainage, but requires previous knowledge of the configuration of the conduit system.

Chen, Zhao; Goldscheider, Nico

2014-06-01

391

Hanford soil partitioning and vapor extraction study  

International Nuclear Information System (INIS)

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

392

Guidance of dorsal root ganglion neurites and Schwann cells by isolated Schwann cell topography on poly(dimethyl siloxane) conduits and films  

Science.gov (United States)

Biomimetic replicas of cellular topography have been utilized to direct neurite outgrowth. Here, we cultured postnatal rat dorsal root ganglion (DRG) explants in the presence of Schwann cell (SC) topography to determine the influence of SC topography on neurite outgrowth. Four distinct poly(dimethyl siloxane) conduits were fabricated within which DRG explants were cultured. To determine the contribution of SC topographical features to neurite guidance, the extent of neurite outgrowth into unpatterned conduits, conduits with randomly oriented SC replicas, and conduits with SC replicas parallel or perpendicular to the conduit long axis was measured. Neurite directionality and outgrowth from DRG were also quantified on two-dimensional SC replicas with orientations corresponding to the four conduit conditions. Additionally, live SC migration and neurite extension from DRG on SC replicas were examined as a first step toward quantification of the interactions between live SC and navigating neurites on SC replicas. DRG neurite outgrowth and morphology within conduits and on two-dimensional SC replicas were directed by the underlying SC topographical features. Maximal neurite outgrowth and alignment to the underlying features were observed into parallel conduits and on parallel two-dimensional substrates, whereas the least extent of outgrowth was observed into perpendicular conduits and on perpendicular two-dimensional replica conditions. Additionally, neurites on perpendicular conditions turned to extend along the direction of underlying SC topography. Neurite outgrowth exceeded SC migration in the direction of the underlying anisotropic SC replica after two days in culture. This finding confirms the critical role that SC have in guiding neurite outgrowth and suggests that the mechanism of neurite alignment to SC replicas depends on direct contact with cellular topography. These results suggest that SC topographical replicas may be used to direct and optimize neurite alignment, and emphasize the importance of SC features in neurite guidance.

Richardson, J. A.; Rementer, C. W.; Bruder, Jan M.; Hoffman-Kim, D.

2011-08-01

393

Liquid-phase compositions from vapor-phase analyses  

Energy Technology Data Exchange (ETDEWEB)

Arsenic normally is not considered to be a contaminant. However, because arsenic was found in many cylinders of UF{sub 6}, including in corrosion products, a study was performed of the distribution of the two arsenic fluorides, AsF{sub 3} and AsF{sub 5}, between liquid and vapor phases. The results of the study pertain to condensation or vaporization of liquid UF{sub 6}. This study includes use of various experimental data plus many extrapolations necessitated by the meagerness of the experimental data. The results of this study provide additional support for the vapor-liquid equilibrium model of J.M. Prausnitz and his coworkers as a means of describing the distribution of various impurities between vapor and liquid phases of UF{sub 6}. Thus, it is concluded that AsF{sub 3} will tend to concentrate in the liquid phase but that the concentration of AsF{sub 5} in the vapor phase will exceed its liquid-phase concentration by a factor of about 7.5, which is in agreement with experimental data. Because the weight of the liquid phase in a condensation operation may be in the range of thousands of times that of the vapor phase, most of any AsF{sub 5} will be in the liquid phase in spite of this separation factor of 7.5. It may also be concluded that any arsenic fluorides fed into a uranium isotope separation plant will either travel with other low-molecular-weight gases or react with materials present in the plant. 25 refs., 3 figs., 6 tabs.

Davis, W. Jr. (Oak Ridge Gaseous Diffusion Plant, TN (USA)); Cochran, H.D. (Oak Ridge National Lab., TN (USA))

1990-02-01

394

Effects of magma and conduit conditions on transitions between effusive and explosive activity: a numerical modeling approach  

Science.gov (United States)

Transitions between effusive and explosive eruptions, common at silicic volcanoes, can occur between distinct eruptive episodes or can occur as changes between effusive and explosive phases within a single episode. The precise causes of these transitions are difficult to determine due to the multitude of mechanisms and variables that can influence fragmentation thresholds. Numerical modeling of magma ascent within a volcanic conduit allows the influence of key variables to be extensively tested. We study the effect of different variables on the mass eruption rate at the vent using a conservative, 1-D, two-phase, steady-state model that allows for lateral gas loss at shallow depths. Several fragmentation criteria are also tested. We are able to generate a number of regime diagrams for a variety of magma and conduit conditions that constrain transitions from effusive to explosive episodes. We show that a transition to explosive activity can occur without changes in the bulk chemistry, crystal volume fraction, or gas mass fraction of the magma. Eruptive style can be controlled by the pressure gradient within the conduit caused by either overpressure in the chamber or varying lava dome size at the vent. Specific results are sensitive to both magma temperature and conduit geometry. It is important that these variables are well constrained when applying this model to different volcanic systems. We apply our model to the recent activity at Merapi Volcano in Indonesia. We constrain model input and output parameters using current petrologic, seismic, and geodetic studies of the Merapi system, and vary critical parameters over reasonable ranges as documented in the literature. Our model is able to reproduce eruption rates observed during both the 2006 effusive and 2010 explosive/effusive eruptions. Our modeling suggests that a combination of chamber overpressure, increased volatile content, and decreased crystal content due to the voluminous injection of new magma into the shallow Merapi system is a plausible cause of explosivity in the 2010 eruption, the most violent at Merapi since 1872. Transitions in eruptive activity were also observed during the 2010 eruptive sequence, where explosive episodes lasting on the scale of hours alternated with longer periods of rapid effusive dome growth. Our modeling suggests these transitions could have been controlled by (1) the degassing behavior of the shallow conduit system without changing the magma supply rate, or (2) alternating conduit magma batches with different H2O content that reflect converging extraction patterns in a volatile-heterogeneous chamber. The latter condition reflects the inevitability for a large eruption to sample, nearly simultaneously, from a wide vertical and horizontal range of locations in a zoned chamber.

Carr, B. B.; De'Michieli Vitturi, M.; Clarke, A. B.; Voight, B.

2013-12-01

395

Sensitivity analysis on parameters and processes affecting vapor intrusion risk  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the vast majority of previous studies, this model accounts for vertical variation of soil water saturation and includes aerobic biodegradation. The attenuation factor (ratio between concentration in the...

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

2012-01-01

396

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

International Nuclear Information System (INIS)

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

397

Le dépistage biologique d'une conduite sous influence Toxicological detection of driving under the influence  

Directory of Open Access Journals (Sweden)

Full Text Available Au cours des 5 à 7 dernières années, beaucoup de progrès ont été faits dans le domaine des méthodes de détection des drogues dans le cadre de la conduite automobile: tests de terrain, seuils de détection optimaux et méthodes de laboratoire. La nécessité de disposer d'un test rapide fiable est bien établie. Les tests rapides urinaires sont assez fiables, mais ils posent le problème de la collecte de l'urine sur le terrain. Le développement des tests sur la salive a été plus lent que prévu, et les problèmes majeurs à résoudre sont la sensibilité pour le tétrahydrocannabinol et l'obtention d'un échantillon satisfaisant (volume et viscosité. Les seuils SAMHSA (Substance Abuse and Mental Health Service Administration qui ont été proposés pour la salive sont également applicables pour les cas de conduite sous influence de drogues. Il y a peu de nouveautés dans les tests rapides sur la sueur. Les seuils analytiques des drogues dans le sang varient dans les différents pays européens et l'Allemagne les a récemment revus à la baisse. L'analyse de drogues dans le sang est maintenant devenue une procédure de routine dans beaucoup de laboratoires, qui utilisent une méthode de chromatographie en phase gazeuse (parfois aussi en phase liquide couplée à la spectrométrie de masse, éventuellement précédée d'un dépistage immunologique. Much progress has been made in the last 5 to 7 years in the field of analytical detection methods for driving under the influence of drugs: roadside tests, optimal cut-offs and laboratory methods. The need for a roadside drug test is now well established. Urine onsite tests work well but the problem of obtaining a urine specimen at the roadside remains. The development of oral fluid tests has been slower than expected, with the sensitivity for tetrahydrocannabinol and adequate (volume and viscosity sampling remaining the major problems. The proposed SAMHSA (Substance Abuse and Mental Health Service Administration cut-offs for oral fluid seem also applicable for driving under the influence of drugs. There has been little development of sweat tests. The analytical cut-offs used differ in European countries and Germany has recently decreased them. Analysis of drugs in blood has now become routine in many labs, either by GCMS, but also by LC-MS, sometimes preceded by an immunoassay screening.

Verstraete Alain G.

2009-03-01

398

Formation of dunite conduits in the mantle: observations from the Lanzo peridotite in NW-Italy  

Science.gov (United States)

Mantle dunites may be the most important conduits for melt transport in the shallow upper mantle (1). Dunites as observed in the Lanzo ophiolites are generally tabular bodies with sharp, replacive contacts and are oriented parallel or discordant to the foliation in the surrounding harzburgite and plagioclase lherzolites (2, 3). In order to evaluate the mechanisms of how dunite formed, we examined in detail dunite - plagioclase lherzolite transects by a combined field, electron microprobe and Laser ablation ICP-MS study. Field observations show that some discordant dunites locally contain small interstitial clinopyroxene, and large clinopyroxene megacrysts sometimes associated with plagioclase. Calculated liquids in equilibrium with clinopyroxenes have REE slopes and concentrations similar to MORB crystallised from low percentage aggregate liquids (less than 5%). In addition spinel in Lanzo dunite is similar to spinels from MORB (4), with high TiO2 and elevated Cr#. Preliminary results on a dunite transect containing a small gabbro dikelet in its center indicate, however, that spinel compositions consistently vary perpendicular to the contact. The Cr#, TiO2 and a number of trace elements (Zn, Co V, Cr, Mn) decrease with increasing distance from the medial gabbro, while Ni increases. In addition, spinels far from the medial gabbro rarely contain inclusions of primary hydrous phases (pargasite and phlogopite). Compositional variations in olivine are more subtle, e.g. contents of compatible trace elements (Co, Ni) are systematically lower in dunite olivine than in olivine from plagioclase lherzolite. The observed spatial chemical variations may reflect melt focussing with time even within a single dunite conduit. These data might be used to place constraints on the relative importance of focused porous flow vs cracks in the shallow mantle. 1. Kelemen, P. B., Hirth, G., Shimizu, N., Spiegelman, M. &Dick, H. J. B. (1997) Philosophical Transactions of the Royal Society of London, Series A. 355, 283-318. 2. Boudier, F. &Nicolas, A. (1972) Schweizerische Mineralogische und Petrographische Mitteilungen 52, 39-56. 3. Boudier, F. (1978) Geological Society of America Bulletin 89, 1574-1591. 4. Dick, H. J. B. &Bullen, T. (1984) Contributions to Mineralogy and Petrology 86, 54-76.

Müntener, O.; Pettke, T.; Piccardo, G.; Zanetti, A.

2003-04-01

399

Terahertz Spectroscopy of Water Vapors, Chemical Vapors and Ionized Air  

Science.gov (United States)

In the past, a few research groups have demonstrated that terahertz spectroscopy could be a useful tool for the identification of chemicals. However most of those demonstrations have been done with solid-phase or liquid-phase chemicals. There are little demonstrations for the detection and identification of chemicals in the gas-phase, as it is very difficult in part due to the presence of water-absorption lines in the terahertz frequency range. As the water absorption lines predominate in the 0.1 - 2THz spectral range, and can interfere with already weak terahertz signatures generated by chemical vapors, it is often very hard to obtain meaningful terahertz spectrum of chemical vapor. Regardless we recently have been able to obtain some terahertz spectra of chemical vapors and ionized air produced by several different ionization sources, including corona discharge and nuclear isotopes. Throughout data analysis we learned that water molecules, nitrogen and oxygen molecules play very important roles in these terahertz spectra. In this presentation we will discuss our experiments and the roles of these molecules.

Graber, Benjamin; Tao, Rongjia; Wu, Dong Ho

2013-03-01

400

Mechanical vapor recompression for waste energy recovery  

Energy Technology Data Exchange (ETDEWEB)

This paper is concerned with energy recovery in petroleum distillation processes utilizing mechanical vapor recompression. Several examples illustrating recompression of head vapors for heating the reboiler of a distillation tower are presented. The advantages of the mechanical vapor recompression system using a screw compressor are discussed in detail. The system is economically attractive with simple payback periods often less than two years. The paper describes the merits of mechanical vapor recompression, using a screw-type compressor for recovering energy at the distillation tower, and how it can be accomplished by using an intermediary fluid such as steam or by recompressing the distillation column vapors directly.

Becker, F.E.; Zakak, A.I.

1985-03-01

 
 
 
 
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