WorldWideScience
1

Drill pipes and casings utilizing multi-conduit tubulars  

Energy Technology Data Exchange (ETDEWEB)

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

Curlett, H.B.

1989-01-24

2

Gastric conduit perforation  

OpenAIRE

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 i...

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

2014-01-01

3

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

4

Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full -- Part 3: Nozzles and Venturi nozzles  

CERN Document Server

ISO 5167-3:2003 specifies the geometry and method of use (installation and operating conditions) of nozzles and Venturi nozzles when they are inserted in a conduit running full to determine the flow-rate of the fluid flowing in the conduit. ISO 5167-3:2003 also provides background information for calculating the flow-rate and is applicable in conjunction with the requirements given in ISO 5167-1. ISO 5167-3:2003 is applicable to nozzles and Venturi nozzles in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of the devices can only be used within specified limits of pipe size and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of nozzles and Venturi nozzles in pipe sizes less than 50 mm or more than 630 mm, or for pipe Reynolds numbers below 10 000. ISO 5167-3:2003 deals with two types of standard nozzles, the ISA 1932 nozzle and the long radius nozzle, as well as the V...

International Organization for Standardization. Geneva

2003-01-01

5

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

6

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

7

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

International Nuclear Information System (INIS)

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

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

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

10

Conduit Coating Abrasion Testing  

Science.gov (United States)

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

Sullivan, Mary K.

2013-01-01

11

A foil shielded flexible conduit  

International Nuclear Information System (INIS)

A foil shielded flexible conduit is described that is suitable for withstanding electromagnetic interference and electromagnetic pulses and may be employed in a nuclear reactor environment. Previous attempts to manufacture such conduits have all suffered from an insufficient degree of flexibility to allow suitable installation and have been liable to breakdown in service. (U.K.)

12

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)

13

Code de conduite du CERN  

CERN Document Server

Le Code de Conduite est un guide pratique qui nous aide, en tant que collaborateurs du CERN, à comprendre comment nous comporter, comment traiter les autres et comment nous attendre à être traités. Il est fondé autour des cinq valeurs fondamentales du CERN. Nous devrons tous nous familiariser avec ce document et l’intégrer à notre vie quotidienne au CERN.

Department, HR

2010-01-01

14

30 CFR 18.39 - Hose conduit.  

Science.gov (United States)

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.39 Hose conduit. Hose conduit shall be...

2010-07-01

15

77 FR 22480 - Conduit Financing Arrangements; Correction  

Science.gov (United States)

...RIN 1545-BH77 Conduit Financing Arrangements; Correction AGENCY: Internal Revenue...providing guidance on conduit financing arrangements. The final regulations apply to multiple-party financing arrangements that are effected through...

2012-04-16

16

76 FR 76895 - Conduit Financing Arrangements  

Science.gov (United States)

...RIN 1545-BH77 Conduit Financing Arrangements AGENCY: Internal Revenue Service...regulations relating to conduit financing arrangements. The final regulations apply to multiple-party financing arrangements that are effected through...

2011-12-09

17

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

18

Left ventricle-aortic conduits in pediatric patients.  

Science.gov (United States)

From August, 1974, to January, 1982, left ventricle-aortic porcine valved conduits were inserted in three patients less than 2 years old (Group 1) and in 10 patients between 2 and 14 years of age (Group 2) for relief of severe left ventricular outflow tract obstruction. The distal anastomosis was made to the ascending aorta in seven patients and to the supraceliac abdominal aorta in six patients. In six patients, the conduit was sutured directly to the left ventricle, and in seven a stented right-angle connector was employed. The left ventricle-aortic gradients were relieved in all cases (mean residual gradient = 4.3 mm Hg). All three patients in Group 1 had associated endocardial fibroelastosis and all died. There was one early death in Group 2 (10% mortality). Reoperation was required in seven of nine survivors (78%) 2.7 to 5.2 years postoperatively for conduit valve failure (five patients), progression of mild native aortic valve insufficiency (one patient), or both (one patient). One of the seven required another reoperation for re-replacement of the conduit valve. There was one late death associated with reoperation. At follow-up 3.4 to 7.5 years postoperatively, four patients are in Functional Class I, two are in Class II, and two are convalescing from reoperation. Left ventricle-aortic conduits provide excellent relief of left ventricular outflow tract obstruction. However, the high incidence of late complications suggests better results might be anticipated with aortoventriculoplasty (Konno). PMID:6738105

DiDonato, R M; Danielson, G K; McGoon, D C; Driscoll, D J; Julsrud, P R; Edwards, W D

1984-07-01

19

Urinary conduits in gynecologic oncology  

International Nuclear Information System (INIS)

Over an 11-year period (1971 to 1981), 212 urinary conduit surgeries were performed by the Department of Gynecology at the University of Texas, M. D. Anderson Hospital and Tumor Institute at Houston. The urinary diversions were performed as part of the pelvic exenteration operation in 154 patients, for radiation injury in 48 patients, and for palliation of disease recurrence in ten patients. Ninety-three percent had prior pelvic radiotherapy. Various segments of the gastrointestinal tract were used, including the ileum (102), sigmoid colon (99), transverse colon (four), jejunum (four), and others (three). Fifty percent of abnormal preoperative intravenous pyelograms reverted to normal after urinary diversion. Revision of the stoma was required in 6%. Other complications included infection (18%), renal loss (17%), and urinary leaks and fistulae (3%). The overall perioperative mortality was 7%, decreasing from 11% in the first five years to 3% during the last six years. Ureteral stents were routinely used. When selecting a segment of bowel for a urinary conduit, both tissue quality and mobility are important. Mortality and morbidity of urinary conduit surgery continues to decrease with experience

20

Imaging of droplets and vapor distributions in a diesel fuel spray by means of a laser absorption-scattering technique.  

Science.gov (United States)

The droplets and vapor distributions in a fuel spray were imaged by a dual-wavelength laser absorption-scattering technique. 1,3-dimethylnaphthalene, which has physical properties similar to those of Diesel fuel, strongly absorbs the ultraviolet light near the fourth harmonic (266 nm) of a Nd:YAG laser but is nearly transparent to the visible light near the second harmonic (532 nm) of a Nd:YAG laser. Therefore, droplets and vapor distributions in a Diesel spray can be visualized by an imaging system that uses a Nd:YAG laser as the incident light and 1,3-dimethylnaphthalene as the test fuel. For a quantitative application consideration, the absorption coefficients of dimethylnapthalene vapor at different temperatures and pressures were examined with an optical spectrometer. The findings of this study suggest that this imaging technique has great promise for simultaneously obtaining quantitative information of droplet density and vapor concentration in Diesel fuel spray. PMID:18354630

Zhang, Y Y; Yoshizaki, T; Nishida, K

2000-11-20

21

Imaging of Droplets and Vapor Distributions in a Diesel Fuel Spray by Means of a Laser Absorption Scattering Technique  

Science.gov (United States)

The droplets and vapor distributions in a fuel spray were imaged by a dual-wavelength laser absorption scattering technique. 1,3-dimethylnaphthalene, which has physical properties similar to those of Diesel fuel, strongly absorbs the ultraviolet light near the fourth harmonic (266 nm) of a Nd:YAG laser but is nearly transparent to the visible light near the second harmonic (532 nm) of a Nd:YAG laser. Therefore, droplets and vapor distributions in a Diesel spray can be visualized by an imaging system that uses a Nd:YAG laser as the incident light and 1,3-dimethylnaphthalene as the test fuel. For a quantitative application consideration, the absorption coefficients of dimethylnapthalene vapor at different temperatures and pressures were examined with an optical spectrometer. The findings of this study suggest that this imaging technique has great promise for simultaneously obtaining quantitative information of droplet density and vapor concentration in Diesel fuel spray.

Zhang, Yu-Yin; Yoshizaki, Takuo; Nishida, Keiya

2000-11-01

22

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

Energy Technology Data Exchange (ETDEWEB)

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

Curlett, H.B.

1997-04-23

23

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

24

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

Directory of Open Access Journals (Sweden)

Full Text Available Estimation of precipitable water (PW in the atmosphere from ground-based Global Positioning System (GPS essentially involves modeling the zenith hydrostatic delay (ZHD in terms of surface Pressure (Ps and subtracting it from the corresponding values of zenith tropospheric delay (ZTD to estimate the zenith wet (non-hydrostatic delay (ZWD. This further involves establishing an appropriate model connecting PW and ZWD, which in its simplest case assumed to be similar to that of ZHD. But when the temperature variations are large, for the accurate estimate of PW the variation of the proportionality constant connecting PW and ZWD is to be accounted. For this a water vapor weighted mean temperature (Tm has been defined by many investigations, which has to be modeled on a regional basis. For estimating PW over the Indian region from GPS data, a region specific model for Tm in terms of surface temperature (Ts is developed using the radiosonde measurements from eight India Meteorological Department (IMD stations spread over the sub-continent within a latitude range of 8.5°–32.6° N. Following a similar procedure Tm-based models are also evolved for each of these stations and the features of these site-specific models are compared with those of the region-specific model. Applicability of the region-specific and site-specific Tm-based models in retrieving PW from GPS data recorded at the IGS sites Bangalore and Hyderabad, is tested by comparing the retrieved values of PW with those estimated from the altitude profile of water vapor measured using radiosonde. The values of ZWD estimated at 00:00 UTC and 12:00 UTC are used to test the validity of the models by estimating the PW using the models and comparing it with those obtained from radiosonde data. The region specific Tm-based model is found to be in par with if not better than a similar site-specific Tm-based model for the near equatorial station, Bangalore. A simple site-specific linear relation without accounting for the temperature effect through Tm is also found to be quite adequate for Bangalore. But for Hyderabad, a station located at slightly higher latitude, the deviation for the linear model is found to be larger than that of the Tm-based model. This indicates that even though a simple linear regression model is quite adequate for the near equatorial stations, where the temperature variations are relatively small, for estimating PW from GPS data at higher latitudes this model is inferior to the Tm-based model.

C. Suresh Raju

2007-10-01

25

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

26

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

27

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

28

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

International Nuclear Information System (INIS)

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

29

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

30

Right ventricle to pulmonary artery conduit reoperations in patients with tetralogy of fallot or pulmonary atresia associated with ventricular septal defect.  

Science.gov (United States)

The short lifespan of right ventricle-to-pulmonary artery (RV-PA) conduits used in repairs of complex congenital heart defects makes future surgical replacement inevitable. Percutaneous pulmonary valve implantation (PPVI) now offers an attractive alternative to surgery in some patients. The objectives of this study were to examine the pattern of conduit reoperations, the factors affecting conduit longevity, and to discuss the role of PPVI in these patients. Forty-nine patients (mean age 27 ± 8 years) with pulmonary atresia or pulmonary stenosis with tetralogy of Fallot who underwent surgery for RV-PA conduits from September 1974 to October 2011 were reviewed. A total of 106 RV-PA conduits were implanted, 57 of which were replacements. Second, third, and fourth conduits were required during the follow-up period in 39, 16, and 2 patients, respectively. Freedom from reoperation at 10 years for the first, second, and third conduits was 50%, 74%, and 86%, respectively. Significant independent predictors of shorter conduit longevity included smaller conduit and conduit type (homograft and other vs Dacron). Furthermore, a significant proportion (32 of 57 [56%]) of conduit replacements took place from ages 9 to 18 years. There were 37 adults whose current existing conduits had not yet failed, with 73% (27 of 37) potentially suitable in the future for PPVI on the basis of conduit size of 16 to 27 mm. In conclusion, multiple RV-PA conduit revisions were required in patients who survived to adulthood, with many replacements taking place during adolescence. Most conduits in this adult cohort met size criteria for PPVI, thereby offering these patients a potential alternative to surgical intervention for conduit failure. PMID:23481618

Ong, Kevin; Boone, Robert; Gao, Min; Carere, Ron; Webb, John; Kiess, Marla; Grewal, Jasmine

2013-06-01

31

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-01-08

32

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

Science.gov (United States)

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 (BA), common femoral (CFA) and popliteal (PA) arteries to account for regional differences in vascular function. In 20 young men, MSNA, mean arterial pressure (MAP), conduit artery diameter, and shear rate (SR) were continuously measured during 20-min periods of supine rest. Spike-triggered averaging was used to characterize beat-by-beat changes in each variable for 15 cardiac cycles following all MSNA bursts, and a peak response was calculated. Diameter increased to a similar peak among the BA (+0.14 ± 0.02%), CFA (+0.17 ± 0.03%), and PA (+0.18 ± 0.03%) following MSNA bursts (all P bursts (P bursts were heterogeneous between arteries and did not appear to systematically alter diameter responses. Thus, in contrast to our hypothesis, spontaneously occurring MSNA bursts do not directly influence conduit arteries with local vasoconstriction or changes in shear, but rather induce a systemic pressor response that appears to passively increase conduit artery diameter. PMID:23832696

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

2013-09-15

33

Externally stented polytetrafluoroethylene valved conduits for right heart reconstruction. An experimental comparison with Dacron valved conduits.  

Science.gov (United States)

Valve-containing conduits have made possible the repair of many congenital anomalies that involve right ventricular-pulmonary arterial discontinuity. The distressing problem of neointimal peel formation with eventual conduit obstruction in patients with Dacron valved conduits has led to the need for premature replacement in many patients. Externally stented polytetrafluorethylene has demonstrated superior patency in the venous system experimentally and clinically and was believed to have potential advantages over Dacron for conduit construction. This study compares the transconduit resistance and the thickness of the neointimal peel in right ventricular-pulmonary arterial conduits constructed of externally stented polytetrafluoroethylene with those of woven Dacron. The 19 mm externally stented polytetrafluoroethylene conduits (Impra, Inc.) containing a Hancock porcine valve (Extracorporeal Inc.) were implanted in six adult mongrel dogs followed by proximal occlusion of the pulmonary artery. In six additional animals, a Dacron valved conduit of similar size and length was inserted. Cardiac output, transconduit gradient, and resistance were measured at operation and at 3 months. All conduits were subsequently explanted, opened longitudinally, and the thickness of the neointimal peel (excluding suture lines) measured. No hemodynamic differences were noted during the 3 month follow-up. However, the thickness of the neointimal peel was fourfold greater in Dacron conduits (609 +/- 144 mu) than in the conduits constructed of externally stented polytetrafluoroethylene (156 +/- 50 mu) (p less than 0.01). The thick peel in Dacron conduits extended into the outflow portion of the porcine valve cusps and prevented their full excision. The neointima in externally stented polytetrafluoroethylene conduits was thin and uniform and did not extend onto the leaflets or limit their mobility. This study demonstrated that the early hemodynamic performance of externally stented polytetrafluoroethylene conduits was comparable to that of Dacron conduits; Dacron conduits were subject to an accelerated rate of peel formation that affected leaflet mobility and may be a factor in early valve degeneration; a thin neointima formed in externally stented polytetrafluoroethylene conduits and valve leaflet motion was preserved. This study showed that externally stented polytetrafluoroethylene conduits offer advantages over Dacron valved conduits and warrant clinical application. PMID:2933562

Brown, J W; Halpin, M P; Rescorla, F J; VanNatta, B W; Fiore, A C; Shipley, G D; Bizuneh, M; Bills, R; Waller, B

1985-12-01

34

Mechanical cleaning of oil spills in seawater using circular conduits  

Energy Technology Data Exchange (ETDEWEB)

Treatment of the crude oil pollution in seawater has attracted global attention during the last two decades. This study was undertaken using circular conduits as a mechanical means to clean oil spills in seawater under different conditions of temperature, oil gravity, shaking frequency, conduit diameter, and initial thickness of oil layer. An experimental model was designed and built to achieve the study. It consists of shaking water bath (to represent sea waves) fitted with temperature controller and glass tubes of different inside diameters of 0.3 cm, 0.5 cm, and 0.7 cm. Three crude oils of different oil gravity of 35{sup o}API, 38{sup o}API, and 47{sup o}API were investigated under different shaking frequencies of 20, 40, and 60 stroke/minute with different tube diameters. The results proved that application of mechanical cleaning of oil spills using circular conduits is a practical technique. The cleaning of black oil spills is more efficient than one of volatile oil. Furthermore, the results indicated that the increase of shaking frequency and/or water temperature provide(s) faster cleaning of oil spills while temperature increase recovers the maximum oil. (Author)

Shedid, S.; Abou Kassem, J.; Zekri, A. [United Arab Emirates Univ., Al Ain City (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

2005-10-15

35

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-12-15

36

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

International Nuclear Information System (INIS)

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

37

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)

38

Norwood-sano operation using a stentless pulmonary valved conduit.  

Science.gov (United States)

The Sano modification of Norwood's operation has the potential to generate an excess volume load on the single right ventricle as a consequence of diastolic reversal of flow through the conduit. This article describes the use of a new, small, biological conduit with a porcine valve inside. This new conduit has been used in modified Norwood procedures. It is interposed between the right ventricle and the confluence of the pulmonary arteries. The use of a valved conduit should prevent the retrograde diastolic blood flow observed with use of nonvalved conduits and may improve postoperative hemodynamics. The use of a new stentless valved conduit in 3 recent Norwood procedures is reported herein. PMID:23804945

Ginestar, Andrés Castelló; Martinez, F Serrano; Argudo, J A Montero; Calvar, J M Caffarena

2011-01-01

39

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

Science.gov (United States)

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

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

2005-11-01

40

Apicoaortic valved conduit without an apical connector.  

Science.gov (United States)

An apicoaortic valved conduit was created in selected aortic stenosis patients with a porcelain aorta, previous bypass surgery, or a high-risk re-sternotomy. Although an apical connector is usually used, commercial, rigid apical connectors are expensive. We introduce a technique that does not use an apical connector. PMID:17937051

Matsuyama, Katsuhiko; Narita, Yuji; Ueda, Yuichi

2007-09-01

41

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.)

42

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

43

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

International Nuclear Information System (INIS)

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

44

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-01-25

45

Phase distribution in complex geometry conduits  

International Nuclear Information System (INIS)

Bubbly air/water two-phase flow data have been taken as an isosceles triangle using hot film probes. It was found that a 3-D two-fluid model was able to predict these data and those taken previously in circular conduits. It appears that mechanically-based CFD predictions of bubbly two-phase flows is possible for many cases of practical concern. (orig.)

46

Biochemical engineering nerve conduits using peptide amphiphiles.  

OpenAIRE

Peripheral nerve injury is a debilitating condition. The gold standard for treatment is surgery, requiring an autologous nerve graft. Grafts are harvested from another part of the body (a secondary site) to treat the affected primary area. However, autologous nerve graft harvesting is not without risks, with associated problems including injury to the secondary site. Research into biomaterials has engendered the use of bioartificial nerve conduits as an alternative to autologous nerve grafts....

Tan, A.; Rajadas, J.; Seifalian, A. M.

2012-01-01

47

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

48

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

49

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

50

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

International Nuclear Information System (INIS)

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

51

Engineering Bi-Layer Nanofibrous Conduits for Peripheral Nerve Regeneration  

OpenAIRE

Trauma injuries often cause peripheral nerve damage and disability. A goal in neural tissue engineering is to develop synthetic nerve conduits for peripheral nerve regeneration having therapeutic efficacy comparable to that of autografts. Nanofibrous conduits with aligned nanofibers have been shown to promote nerve regeneration, but current fabrication methods rely on rolling a fibrous sheet into the shape of a conduit, which results in a graft with inconsistent size and a discontinuous joint...

Zhu, Yiqian; Wang, Aijun; Patel, Shyam; Kurpinski, Kyle; Diao, Edward; Bao, Xuan; Kwong, George; Young, William L.; Li, Song

2011-01-01

52

Neurotrophin releasing single and multiple lumen nerve conduits  

OpenAIRE

Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and proces...

Yang, Yang; Laporte, Laura; Rives, Christopher B.; Jang, Jae-hyung; Lin, Wei-chun; Shull, Kenneth R.; Shea, Lonnie D.

2005-01-01

53

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

54

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)

55

Conduits and dike distribution analysis in San Rafael Swell, Utah  

Science.gov (United States)

Volcanic fields generally consist of scattered monogenetic volcanoes, such as cinder cones and maars. The temporal and spatial distribution of monogenetic volcanoes and probability of future activity within volcanic fields is studied with the goals of understanding the origins of these volcano groups, and forecasting potential future volcanic hazards. The subsurface magmatic plumbing systems associated with volcanic fields, however, are rarely observed or studied. Therefore, we investigated a highly eroded and exposed magmatic plumbing system on the San Rafael Swell (UT) that consists of dikes, volcano conduits and sills. San Rafael Swell is part of the Colorado Plateau and is located east of the Rocky Mountain seismic belt and the Basin and Range. The overburden thickness at the time of mafic magma intrusion (Pliocene; ca. 4 Ma) into Jurassic sandstone is estimated to be ~800 m based on paleotopographical reconstructions. Based on a geologic map by P. Delaney and colleagues, and new field research, a total of 63 conduits are mapped in this former volcanic field. The conduits each reveal features of root zone and / or lower diatremes, including rapid dike expansion, peperite and brecciated intrusive and host rocks. Recrystallized baked zone of host rock is also observed around many conduits. Most conduits are basaltic or shonkinitic with thickness of >10 m and associated with feeder dikes intruded along N-S trend joints in the host rock, whereas two conduits are syenitic and suggesting development from underlying cognate sills. Conduit distribution, which is analyzed by a kernel function method with elliptical bandwidth, illustrates a N-S elongate higher conduit density area regardless of the azimuth of closely distributed conduits alignment (nearest neighbor distance <200 m). In addition, dike density was calculated as total dike length in unit area (km/km^2). Conduit and sill distribution is concordant with the high dike density area. Especially, the distribution of conduits is not random with respect to the dike distribution with greater than 99% confidence on the basis of the Kolmogorov-Smirnov test. On the other hand, dike density at each conduits location also suggests that there is no threshold of dike density for conduit formation. In other words, conduits may be possible to develop from even short mapped dikes in low dike density areas. These results show effectiveness of studying volcanic vent distribution to infer the size of magmatic system below volcanic fields and highlight the uncertainty of forecasting the location of new monogenetic volcanoes in active fields, which may be associated with a single dike intrusion.

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

2011-12-01

56

Apicoaortic conduits: indications, complications, and imaging techniques.  

Science.gov (United States)

Left ventricular apex to descending aorta conduits may be used as a last resort treatment of severe left ventricular outflow tract obstruction in cases in which alternative therapies are contraindicated. Although this technique is rarely used in current practice for congenital cases, its use in the elderly population is increasing, largely due to the expansion of this patient cohort and associated comorbidities precluding aortic valve replacement, the most common of which are a severely calcified "porcelain" aorta and/or previous coronary artery bypass grafts preventing aortic root manipulation. Diagnostic imaging is essential in the presurgical workup and subsequent follow-up of these patients, as complications of the procedure are potentially life threatening and are not rare. Several imaging modalities may be used, each with advantages and disadvantages. Both anatomic and functional assessments play a role in the comprehensive evaluation of both presurgical and postsurgical patients. PMID:22510854

Nance, John W; Barraza, J Michael; Henzler, Thomas; McMaster, William G; Kratz, John M; Schoepf, U Joseph

2012-05-01

57

Proximal conduit obstruction after Sano modified Norwood procedure.  

Science.gov (United States)

Sano and colleagues recently described a modification of first stage palliation for hypoplastic left heart syndrome utilizing a right ventricle to pulmonary artery conduit. Preliminary results are favorable, but experience with this technique is limited. We report a case of sudden death due to obstruction of the proximal conduit by fibrointimal hyperplasia. This case of lethal conduit obstruction presented 3 months after initial palliation. Early cardiac catheterization and second stage palliation may be necessary to minimize the risk of such adverse events after the Sano modification. PMID:16242490

Nigro, John J; Bart, Robert D; Derby, Christopher D; Sklansky, Mark S; Starnes, Vaughn A

2005-11-01

58

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

Science.gov (United States)

The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2–8 weeks), the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury. PMID:25788923

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

2015-01-01

59

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)

60

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

61

Preclinical evaluations of acellular biological conduits for peripheral nerve regeneration  

OpenAIRE

Various types of natural biological conduits have been investigated as alternatives to the current surgical standard approach for peripheral nerve injuries. Autologous nerve graft, the current gold standard for peripheral nerve damage, is limited by clinical challenges such as donor-site morbidity and limited availability. The purpose of this study was to evaluate the efficacy of using acellular xenographic conduits (nerve, artery, and dermis) for the repair of a 1.2 cm critical size defect o...

Liao, I-chien; Wan, Hua; Qi, Shijie; Cui, Cunqi; Patel, Paarun; Sun, Wendell; Xu, Hui

2013-01-01

62

Guided regeneration with resorbable conduits in experimental peripheral nerve injuries  

OpenAIRE

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

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

2000-01-01

63

Significance of Conduit Flow in a Highly Heterogeneous Karst Basin  

Science.gov (United States)

Two numerical models are applied to simulate the groundwater flow in a conduit network (subsurface stream) embedded in a mature karst system in Houzhai Basin, southwest China. The main difference between these two models is the treatment of the horizontal conduit network. In the first model, the Drain module in Visual MODFLOW model is used to simulate the subsurface stream based on equivalent continuum model where flows are assumed to be laminar. In the second model, the Conduit Flow Process (CFP) module based on dual-conductivity model is used where potential turbulent flows in conduit network are taken into account. The vertical conduits (sinkholes) are set as injecting wells to increase the underground runoff in both models. The high heterogeneity of karst system and the lack of observed hydrogeologic data significantly affect the performance of the numerical models. Uncertainty and sensitivity analysis is conducted covering possible ranges of the most influential parameters. Modeling results suggest that the groundwater flows are highly sensitive to several parameters, such as conduit paths. The differences in hydrological processes and parameter sensitivities between the two models highlight the potential errors in the equivalent continuum model.

Zhang, R.; Zhu, J.; Shu, L.

2011-12-01

64

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-12-31

65

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)

66

Comminution and frictional melting in volcanic conduits  

Science.gov (United States)

Shearing and faulting at active volcanoes may differ to tectonic faulting due to their distinct temperature conditions above those of the Earth's geotherm. In particular, the ascent of high-viscosity magma/rocks in upper conduits leads to shear/fault zones, with/without gouge formation and sometimes frictional melting; yet, details of the deformation and fracture mechanisms in these magma/rocks with different crystallinities reveal a different synopsis. For instance, the extrusion of lava domes proceeds endogenously or exogenically - a distinction generally understood as a shift in magma rheology to brittle failure, without consideration of the subsequent slip process. Exogenic growth and formation of a spine follow the dynamic rupture of the lava and the dome carapace, and suffer slip along the fault surface. Here, we present experimental investigations of the ability of volcanic rocks (with different glass/crystal and vesicle ratios) to sustain friction, and in cases melt, using a high-velocity rotary apparatus. During high-velocity rotary shear test, we find that slip of along andesite and basalt rocks generate heat which leads to frictional melting at temperature of ca. 1000 C, conciding to a total slip of 10-40 m (for slip initiating at room temperature). In contrast, slip along dense obsidian rocks or porous rocks cannot sustain slip along a discrete plane. Alternatively, obsidian can be slipped against a crystalline material. The width of the slip zone decreases in the presence of crystals. The findings suggest that the comminution of crystals is a requirement to the development of a localised slip zone. In absence of crystals, obsidian (and crystal-free magma) shatter catastrophically. We discuss the implication of our findings to the cases of tectonic faults, stability of volcanic edifices and evolution of lava dome eruptions.

Lavallee, Y.; Mitchell, T. M.; Heap, M. J.; Kendrick, J. E.; kennedy, B.; Ashwell, P. A.; Hirose, T.; Dingwell, D. B.

2011-12-01

67

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

Directory of Open Access Journals (Sweden)

Full Text Available O conceito do uso de um conduto extracardíaco para estabelecer uma via de saída, conectando o ventrículo direito com o tronco pulmonar, ou seus ramos, foi desenvolvido na década de 60. Entre 1971 e 1986, 335 pacientes receberam, no The Hospital for Sick Children, de Londres, condutos extracardíacos para o lado direito do coração; 176 destes foram homoenxertos aórticos, preservados em solução antibióticonutriente; 140 heteroenxertos (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley e 19 tubos não valvulados. Estes condutos foram usados na correção de defeitos cardíacos complexos. A idade média foi de 6,34 anos e o peso médio, de 17,8 kg. O diâmetro interno dos condutos variou de 8 a 30 mm. A mortalidade hospitalar foi de 29,2% e o seguimento dos sobrevivente teve uma duração máxima de 14,3 anos, sendo que apenas 40% delas foram relacionadas ao conduto extracardíaco. A curva atuarial, livre de obstrução, dos condutos extracardíacos foi significativa, quando se analisaram os homoenxertos, face a cada grupo de heteroenxertos (p The concept of using extracardiac conduits, to establish an outflow tract between the right ventricle and the pulmonary artery was developed on the sixties. Between 1971 and 1986, 335 patients received extracardiac conduits for the right heart, at The Hospital for Sick Children, London; 176 were antibiotic preserved aortic homografts (Hancock, Ross, Carpentier-Edwards, lonescu-Shiley and 19 non-valved tubes. These conduits were used for the repair of complex congenital heart defects. The mean age of these groups was 6.34 ± 4.6 years and the mean weight 17.8 ± 10.8 kg. The internal diameter of the conduits varied from 8 to 30 mm. The hospital mortality was 29.2% and long-term follow-up of the survivals had a maximum period of 14,39 years. Sixty patients (17.9% were submited to 60 reoperations, being only 40% conduit related. The actuarial survival cun/e of freedom from obstruction was significant when analyzed the homografts, without Dacron, versus each group of heterografts (p < 0.005. The more important risk factors were the number of postoperative complications, for late deaths; the severity of associated lesions for reoperation, the date of surgery for the replacement of the extracardiac conduit, and the date of surgery and severity of associated lesions for the obstruction of the extracardiac conduits. We conclude that on long-term the use of extracardiac valved conduits has good results specially when using antibiotic preserved aortic homografts and therefore they are our first choice in the reconstruction of the pulmonary ventricle outflow tract.

Rui Siqueira de Almeida

1988-08-01

68

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

69

Development of conduits for the ITER central solenoid conductor  

International Nuclear Information System (INIS)

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

70

TiN film deposition on stainless steel by means of nitrogen ion beam and ionized Ti vapor and evaluation of its properties  

International Nuclear Information System (INIS)

430-type stainless steel plates were coated with TiN films by four methods, ion beam assisted deposition (IBAD), ionization deposition (ID), ion beam assisted ionization deposition (IBAID) and ion plating (IP), and their color coordinates, microhardness, adhesion and deposition layer structure were compared. In IBAD, golden-colored TiN film was obtained at the substrate temperature higher than 700degC, at the nitrogen ion beam energy of about 200 eV and at the deposition rate lower than 0.19 nm/sec, while it was obtained at 400degC and at high deposition rate in ID, IBAID and IP. The TiN films deposited by the above mentioned four methods had almost the same microhardness (about 2250 kgf/mm2) and void-free dense structure. The adhesion of the TiN film deposited by IBAD was higher than those by the other three methods. This was considered to be due to the high mixing effect on the interface which was arose both from the high substrate temperature and from the high current density of nitrogen ion beam compared to the amount of Ti vapor flux. (author)

71

Phase distribution phenomena in triangular conduits  

International Nuclear Information System (INIS)

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

72

Sciatic nerve repair using adhesive bonding and a modified conduit.  

Science.gov (United States)

When repairing nerves with adhesives, most researchers place glue directly on the nerve stumps, but this method does not fix the nerve ends well and allows glue to easily invade the nerve ends. In this study, we established a rat model of completely transected sciatic nerve injury and repaired it using a modified 1 cm-length conduit with inner diameter of 1.5 mm. Each end of the cylindrical conduit contains a short linear channel, while the enclosed central tube protects the nerve ends well. Nerves were repaired with 2-octyl-cyanoacrylate and suture, which complement the function of the modified conduit. The results demonstrated that for the same conduit, the average operation time using the adhesive method was much shorter than with the suture method. No significant differences were found between the two groups in sciatic function index, motor evoked potential latency, motor evoked potential amplitude, muscular recovery rate, number of medullated nerve fibers, axon diameter, or medullary sheath thickness. Thus, the adhesive method for repairing nerves using a modified conduit is feasible and effective, and reduces the operation time while providing an equivalent repair effect. PMID:25206861

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

2014-03-15

73

Interactions of large amplitude solitary waves in viscous fluid conduits  

CERN Document Server

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

Lowman, Nicholas K; El, Gennady A

2013-01-01

74

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

75

[Two cases of severe variceal haemorrhage from an ileal conduit.  

Science.gov (United States)

Variceal haemorrhage from an ileal conduit is a rare but well-known complication to portal hypertension. Many treatments are described and a transjugular intrahepatic portosystemic shunt (TIPS) is the treatment of choice if possible, because this addresses the underlying portal hypertension. We report two cases of haemorrhage from an ileal conduit, which illustrates that treatment must be individualized with attention to life expectancy, co-morbidities and degree of the portosystemic pressure gradient, but TIPS treatment has to be considered even if there is no history of liver disease. PMID:25294334

Lunden, Dagmar; Poulsen, Johan; Kloster, Brian O

2014-09-22

76

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

77

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

78

Numerical study of axonal outgrowth in grooved nerve conduits  

Science.gov (United States)

Nerve conduits with grooved inner texture, working as a topographical guidance cue, have been experimentally proved to play a significant role in axonal alignment. How grooved conduits guide axonal outgrowth is of particular interest for studying nerve regeneration. A viscoelastic model of axonal outgrowth in a conduit with a defined grooved geometry characterized by its width in the circumferential direction and its height in the radial direction is developed in this work. In this model, the axon is considered as an elastic beam and the axonal deformation and motion, including stretching, bending and torsion, are described using a Cosserat rod theory. The friction between axon and substrate is also considered in this model as well as the tip outgrowth. It is found that the directional outgrowth of the axon can be significantly improved by the grooved texture: when the groove width decreases or the groove height increases, the axonal elongation in the longitudinal direction of the conduit can be increased, which is in good agreement with experimental observations. This work is the first numerical model to study the effect of the substrate geometry on axonal outgrowth.

Yin, Jun; Coutris, Nicole; Huang, Yong

2012-10-01

79

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

80

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kojo, Y.; Sekine, N.; Tada, S.; Yamaguchi, Y.; Obama, J.; Takao, T.; Miyagi, D.; Yamanaka, A

2003-10-15

81

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

OpenAIRE

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

82

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

Science.gov (United States)

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

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

2004-09-01

83

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

84

CODUL EUROPEAN DE BUN? CONDUIT? ADMINISTRATIV? ?I FENOMENUL ADMINISTRATIV ROMÂNESC  

Directory of Open Access Journals (Sweden)

Full Text Available Pour vivre parmi les membres d¢une certaine collectivité humaine, il est absolument nécessaire de connaître et respecter les valeurs fondamentales de celle-ci. Il est nécessaire également de respecter et d’appliquer les lignes de conduite importées par les normes juridiques réglementant les relations sociales qui se forment dans la collectivité respective pour realiser et protéger ces valeurs. Le peuple roumain, étant impliqué dans la procedure d¢adhésion à l¢Union européenne, a le devoir de connaître le droit communautaire. Le législateur roumain a la mission d'élaborer et d'adopter des lois compatibles avec les normes juridiques communautaires. L'exécutif doit agir pour que les lois soient appliques par tous ceux qui l’exécutif vivent en Roumanie. Par couséquence, il est absolument nécessaire de réformer l'administration publique roumaine de sorte que la relation fonctionnaire public et autres agents de l'administration publique – citoyen destinataire et bénéficiaire de la décision administrative et de la prestation administrative, soit conforme aux standards de l'Union européenne. Cet ouvrage a comme but de présenter en quelle mesure les règles écrites dans le Code européen de bonne conduite administrative peuvent être un modèle pour le législateur roumain. Même si le Code européen de bonne conduite administrative est un document rédigé pour établir les principes généraux à observer dans les relations entre les institutions communautaires européennes et le public, nous considerons qu'il y a plusieurs raisons pour considérer ce Code comme un modèle digne d'être suivi dans l'activité du législateur roumain. Parmi ces raisons, se trouve la performance d'établir le contenu de la base légale pour la bonne conduite administrative utilisant seulement vingt-sept articles dans lesquels on précise les principes généraux pour ce domaine d'activité sociale. Donc, le caractère concis et pourtant explicite du texte est un modèle pour une loi roumaine concernant la bonne conduite administrative ou pour un chapitre du Code administratif, chapitre ayant comme sujet la bonne conduite administrative. Une autre raison est celle que des principes comme „légitimité”, „absence de discri­mination”, „la proportionnalité”, „absense d'abus de pouvoir”, „impartialité et indépendance”, „objectivité”, „équité”, „confiance légitime, cohérence et conseil” et „courtoisie” doivent être présents parmi les principes fondamentaux de l'administration publique, quel que soit le pays dont il s'agit.

Alina Nicu

2006-05-01

85

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

86

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

87

Deep conduit flow in karst aquifers revisited  

Science.gov (United States)

Caves formed in soluble rocks such as limestone, anhydrite, or gypsum are efficient drainage paths for water moving through the aquifer from the surface of the host rock toward a resurgence. The formation of caves is controlled by the physical solution through dissociation of the host rock by water or by the chemical solution through reactions of the host rock with water enriched with carbon dioxide. Caves as large underground voids are simply the end-member of secondary porosity and conductivity characterizing the aquifer. Caves and their relation to a present or past base level are found both close to a past or present water table (water table caves) and extending far below a past or present water table (bathy-phreatic caves). One explanation for this different speleogenetic evolution is the structural control: fractures and bedding partings are preferentially enlarged around more prominent faults, thus the fracture density in the host rock controls the speleogenetic evolution. This widely accepted explanation can be extended by adding other controls, e.g., a hydraulic control: as temperature generally increases with depth, density and viscosity of water change, and particularly the reduction of viscosity due to the increase in temperature enhances flow. This hypothesis was proposed by Worthington (2001, 2004) as a major controlling factor for the evolution of deep bathy-phreatic caves. We compare the efficiency of structural and hydraulic control on the evolution of a cave passage by numerical means, adding a third control, the chemical control to address the change in solubility of the circulating water with depth. Our results show that the increase in flow through deep bathy-phreatic passages due to the decrease in viscosity is by far outweighted by effects such as the decrease in fracture width with depth due to lithostatic stress and the decrease in solubility with depth. Hence, the existence of deep bathy-phreatic cave passages is more likely to be controlled by the structural effect of prominent faults.

Kaufmann, Georg; Gabrovšek, Franci; Romanov, Douchko

2014-06-01

88

Histological and environmental changes in longstanding ileal conduits.  

OpenAIRE

Seventeen patients with urinary diversions present for between 10 and 17 years were examined endoscopically. The region of the anastomosis was successfully biopsied in 13 cases. Biopsy specimens were examined both histologically and cytologically. Urine was aspirated from the conduits under sterile conditions and sent for qualification of bacterial flora. Histology revealed a variable degree of villous atrophy, mucosal metaplasia, crypt hyperplasia and in one case, antral type gland metaplasi...

Thomas, D. J.; Goble, N. M.; Gillatt, D. A.; Hammonds, J. C.; Smith, P. J.

1990-01-01

89

CODUL EUROPEAN DE BUN? CONDUIT? ADMINISTRATIV? ?I FENOMENUL ADMINISTRATIV ROMÂNESC  

OpenAIRE

Pour vivre parmi les membres d¢une certaine collectivité humaine, il est absolument nécessaire de connaître et respecter les valeurs fondamentales de celle-ci. Il est nécessaire également de respecter et d’appliquer les lignes de conduite importées par les normes juridiques réglementant les relations sociales qui se forment dans la collectivité respective pour realiser et protéger ces valeurs. Le peuple roumain, étant impliqué dans la procedure d¢adhésion à l¢Union européen...

Alina Nicu

2006-01-01

90

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)

91

Inferring conduit process from population studies of cinder cone craters  

Science.gov (United States)

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

Bemis, Karen G.

2014-05-01

92

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

93

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)

94

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

Directory of Open Access Journals (Sweden)

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

Karine F. Meyer

2008-03-01

95

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

Scientific Electronic Library Online (English)

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

Karine F., Meyer; Mauricio, Macedo; Humberto, S. Filho; Thais R., Pinto; Leonan T., Galvao; Quirino C., Meneses.

2008-03-01

96

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

Scientific Electronic Library Online (English)

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

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

2009-12-01

97

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

Scientific Electronic Library Online (English)

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

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

1988-08-01

98

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

99

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

100

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)

101

Séparation de la source glottique des influences du conduit vocal  

OpenAIRE

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

Degottex, Gilles

2010-01-01

102

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

OpenAIRE

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)...

Yan Qiongjiao; Yin Yixia; Li Binbin

2012-01-01

103

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

104

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

105

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

Directory of Open Access Journals (Sweden)

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

OSCAR ARANGO

2009-12-01

106

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-03-01

107

Calibrated vapor generator source  

Science.gov (United States)

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

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

1995-01-01

108

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

International Nuclear Information System (INIS)

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

109

Palliative urinary conduit diversion in cases of intolerable urinary discomfort  

Energy Technology Data Exchange (ETDEWEB)

Fifteen patients with incurable gynecological cancers, all primary radiation treated and all having severe urinary discomfort due to urinary tract injuries were retrospectively examined after urinary conduit diversion. All have been followed-up until termination or until all survivors had lived for 6 months after the operation. Twelve of the 15 were discharged from the hospital, 10 of whom survived the first 6 months. Of those discharged 82% of the cumulated sum of postoperative observations days was spent out of the hospital. At the end of the observation period nine patients had been supplied with a colostomy as well, thus having double stomas. All six patients still alive declared in retrospect that given the choice again, they would still be willing to undergo the operation.

Lyndrup, J.; Sorensen, B.L.

1983-12-01

110

Hot upwelling conduit beneath the Atlas Mountains, Morocco  

Science.gov (United States)

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

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

2014-11-01

111

[A case of curatively resected, locally advanced ascending colon cancer with ileal conduit invasion].  

Science.gov (United States)

A 71 -year-old man was referred to our hospital because of repeated bowel obstruction. He had previously undergone cystectomy with ileal conduit urinary diversion for the treatment of bladder cancer at the age of 28 years. Computed tomography revealed a mass in the ascending colon. Ileostomy was initially performed because of poor general condition that improved with postoperative nutrition management. Enema findings revealed ascending colon cancer and we therefore decided to perform curative surgery. Intraoperative findings revealed that the ascending colon cancer had invaded the ileal conduit. However, it was confirmed that the ureter-ileal conduit anastomosis and the mesentery of the ileal conduit could be preserved. We performed right colectomy and partial resection of the ileal conduit with curative intent. The pathological stage was pT4bpN0cM0, pStage II. There were no signs of recurrence 15 months after curative surgery. PMID:25731293

Kameyama, Hitoshi; Shimada, Yoshifumi; Nogami, Hitoshi; Nakano, Mae; Nakano, Masato; Sakata, Jun; Kobayashi, Takashi; Minagawa, Masahiro; Kosugi, Shinichi; Koyama, Yu; Wakai, Toshifumi

2014-11-01

112

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

Science.gov (United States)

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

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

113

Modelling conduit-matrix exchange processes in a karst aquifer  

Science.gov (United States)

The objective of this work is to identify the relevance of gradient exchange between karst conduits and fissured matrix for interpretation of karst spring responses. The numerical control volume finite element FRAC3DVS/HydroGeoSphere model (Therrien and Sudicky 1996) is used to simulate discharge and transport signals (18O) at the karst spring Gallusquelle (Swabian Alb, South Germany) for a period of two years. The chosen double continuum approach accounts for saturated and unsaturated flow conditions in the karst system. Important model parameters were identified using sensitivity analyses. Model input was generated using a soil-moisture balance approach that accounts for evaporation, interception and snow storage (Geyer 2008). In general, karst aquifers are characterized by a dual flow system consisting of a low permeability matrix with high storage and a secondary system of highly conductive conduits with low storage. The interaction between both systems represents one of the characteristics of karst aquifers, displayed especially after recharge events, i.e. a characteristic rapid increase in discharge and slow recession. A further important indicator is the variation of isotopic spring signals, e.g. the relative abundance of 18O in spring water. During long-term recession, a systematic decrease in 18O was observed, which is interpreted as the release of isotopically lighter water, recharged during the winter period several years ago. It is believed that this behaviour can be related to: (1) gradient inversion during high recharge conditions and (2) storage in the matrix system and subsequent release of water.

Kordilla, J.; Geyer, T.; Graf, T.; Sauter, M.

2009-04-01

114

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

115

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

116

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

117

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

118

PDLLA/chondroitin sulfate/chitosan/NGF conduits for peripheral nerve regeneration.  

Science.gov (United States)

Biodegradable PDLLA/Chondroitin sulfate/Chitosan(PDLLA/CS/CHS) nerve conduits with potentially good biocompatibility and good mechanical property feasible for surgical manipulation have been developed in our previous work. The purpose of this study was to investigate their possible application in repairing damaged nerves and the effect of nerve growth factor (NGF). The PDLLA/CS/CHS/NGF nerve conduits were prepared by immobilizing NGF onto the PDLLA/CS/CHS nerve conduits with carbodiimide. Adult Sprague-Dawley (SD) rats weighing 200-250 g were used as the animal model. The conduits were employed to bridge the 10 mm defects in the sciatic nerve of the SD rats. Nerve conduction velocities (NCVs) were clearly detected in both nerve conduits after 3 months of implantation, indicating a rapid functional recovery for the disrupted nerves. The results of histological sections showed that the internal sides of the conduits were compact enough to prevent the connective tissues from ingrowth. Combined with the strong mechanical properties, good nerve regeneration ability and non-toxicity of its degradation products, PDLLA/CS/CHS nerve conduits would be expected to be useful materials to repair nerve damage and NGF can effectively promote the regeneration of peripheral nerve defect. PMID:21397324

Xu, Haixing; Yan, Yuhua; Li, Shipu

2011-07-01

119

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.

120

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-15

121

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

Science.gov (United States)

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

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

2014-01-01

122

A nonlinear analysis methodology for the one hole malleable iron conduit clamp  

International Nuclear Information System (INIS)

A generalized nonlinear finite element methodology for determining the load-deflection behavior of a malleable iron one hole conduit clamp is developed. This clamp is used to support electrical-conduit in industry and nuclear power plants. Two different types of one hole malleable iron conduit clamps are analyzed using two dimensional plane stress finite element models. The analysis used the following nonlinear options: large displacement option, interface option, plasticity option, and bilinear material stress-strain capabilities. The analytical methodology gives similar results to those measured in actual clamp tests

123

Liquid metal vapor deposition preventive device  

International Nuclear Information System (INIS)

The device of the invention comprises, in an annular gap of a shielding portion at the upper portion of a reactor container, supplying means for supplying helium gases from above the annular gap and detection means for detecting the concentration of vaporized liquid metal vapors or helium gases by using a sensor below the annular gap portion. Then, helium is injected into the gap by opening a control valve depending on the detected signal. This can prevent the displacement of metal vapors to the low temperature portion by filling the annular gap penetrating the shielding portion with helium of low specific gravity thereby forming a boundary of metal vapors and helium in the high temperature portion below the gap. Accordingly, a highly reliable device can be obtained by such simple constitution. (T.M.)

124

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

125

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, Harold F.; Ruppel, C.; Juanes, R.

2011-01-01

126

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

127

Coronary artery reoperations using arterial conduits: immediate and early results.  

Science.gov (United States)

This study deals with results of coronary artery reoperations in 21 males aged 54.4 +/- 6.6 years. Native vessel coronary disease at first and second operation was nearly the same (2.7 +/- 0.6 vs 2.8 +/- 0.4 vessel, p = NS). Graft attrition and deterioration in left ventricular ejection fraction (55.9 +/- 9.2 initial vs 36 +/- 15 at reoperation, p < 0.001) necessitated reoperation in majority. Recurrence of angina (71%) and left ventricular failure (23.8%) were the clinical indicators for reoperation. Procedure was successful in 20 (95%) and had to be abandoned in 1 due to severe pericardial and sternal adhesions. Arterial grafts were utilised in 90% (18 cases, Group A and B). Total arterial revascularisation (Group A) was done in 9 (45%) using Y graft 6, combination of both mammary arteries 2, and by both mammary and inferior epigastric artery in 1. Group B patients had arterial grafts (bilateral IMA 1, Y graft 1, bilateral IMA + gastroepipolic 1, RIMA 4, and LIMA 2) in addition to a venous graft. Two patients (group C, 10%) had only venous grafts. There was no in hospital mortality or morbidity and at 10 +/- 5.2 months follow up, all are asymptomatic with negative stress test at 3 months followup in 8 cases. We conclude that coronary artery reoperations using arterial conduits can be performed safely with excellent immediate and early results. PMID:7797222

Sharma, S; Daxini, B V; Trivedi, A; Mukherjee, K; Pinto, R; Bhattacharya, S

1994-01-01

128

Prediction of the phase distribution in a triangular conduit  

International Nuclear Information System (INIS)

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

129

Prediction of the void coring phenomena in a triangular conduit  

International Nuclear Information System (INIS)

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

130

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1990-12-31

131

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

132

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

Directory of Open Access Journals (Sweden)

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

133

Numerical simulation of the mechanical behavior of the ITER cable-in-conduit conductors  

OpenAIRE

The ITER Cable-In-Conduit Conductors (CICC) are composed of an assembly of pure copper wires and composite superconducting strands (with embedded brittle Nb3Sn microfilaments) cabled together and inserted in a stainless steel jacket. If the current carrying capacities of individual ITER strand are clearly identified, by a dependence of the critical current on the applied strain and by a statistical quantification of possible microfilaments breakage, the characterization of cable-in-conduit is...

Bajas, Hugues

2011-01-01

134

Bone Marrow Mesenchymal Stem Cell and Vein Conduit on Sciatic Nerve Repair in Rats  

Science.gov (United States)

Background: Peripheral nerve repair with sufficient functional recovery is an important issue in reconstructive surgery. Stem cells have attracted extensive research interest in recent years. Objectives: The purpose of this study was to compare the vein conduit technique, with and without the addition of mesenchymal stem cells in gap-less nerve injury repair in rats. Materials and Methods: In this study, 36 Wistar rats were randomly allocated to three groups: In the first group, nerve repair was performed with simple neurorrhaphy (control group), in the second group, nerve repair was done with vein conduit over site (vein conduit group) and in the third group, bone marrow stem cells were instilled into the vein conduit (stem cell group) after nerve repair with vein conduit over site. Six weeks after the intervention, the sciatic function index, electrophysiological study and histological examination were performed. Results: All animals tolerated the surgical procedures and survived well. The sciatic function index and latency were significantly improved in the vein conduit (P = 0.04 and 0.03, respectively) and stem cell group (P = 0.02 and 0.03, respectively) compared with the control group. No significant difference was observed in sciatic function and latency between the vein conduit and stem-cell groups. Moreover, histological analysis showed no significant difference in regenerative density between these two groups. Conclusions: The results of this study showed that the meticulous microsurgical nerve repair, which was performed using the vein tubulization induced significantly better sciatic nerve regeneration. However, the addition of bone marrow mesenchymal stem cell to vein conduit failed to promote any significant changes in regeneration outcome.

Seyed Foroutan, Kamal; Khodarahmi, Ali; Alavi, Hootan; Pedram, Sepehr; Baghaban Eslaminejad, Mohamad Reza; Bordbar, Sima

2015-01-01

135

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

136

A Biosynthetic Nerve Guide Conduit Based on Silk/SWNT/Fibronectin Nanocomposite for Peripheral Nerve Regeneration  

OpenAIRE

As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT cond...

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

2013-01-01

137

Conditions for detection of ground deformation induced by conduit flow and evolution  

OpenAIRE

At mature andesitic volcanoes, magma can reach the surface through the same path for several eruptions thus forming a volcanic conduit. Because of degassing, cooling, and crystallization, magma viscosity increase in the upper part of the conduit may induce the formation of a viscous plug. We conducted numerical simulations to quantify the deformation field caused by this plug emplacement and evolution. Stress continuity between Newtonian magma flow and elastic crust is considered. Plug emplac...

Albino, F.; Pinel, Virginie; Massol, H.; Collombet, M.

2011-01-01

138

Hemodynamic significance of coronary jet velocity in patients: limitations of the Bernouilli equation in small conduits.  

Science.gov (United States)

The objective of this study was to assess the use of coronary stenosis velocity in the determination of translesional pressure gradients. In the physiologic assessment of coronary stenosis, the accelerated intracoronary flow velocity within a narrowing has correlated with minimal lesion cross-sectional area according to the continuity equation. In large conduits the jet velocity can determine pressure gradients when used in the Bernouilli equation. However, the use of intralesional flow velocity for calculation of translesional pressure gradients by the simplified Bernouilli equation (delta P = 4V2) may be inaccurate in small (proximal and distal pressure and planimetry of the instantaneous phasic pressure gradient were used and compared with the instantaneous velocity calculations of pressure by the simplified Bernouilli formula with both maximal jet velocity and a modified formula including proximal velocity. The mean measured translesional pressure gradient was 18 +/- 13 mm Hg (range 0 to 50 mm Hg) and was equivalent to the instantaneous average pressure gradient by planimetry. The maximal jet velocity was 125 +/- 40 cm/sec (range 63 to 250 cm/sec), yielding a calculated pressure gradient of 3 +/- 3 mm Hg. The calculated pressure gradient by the simplified Bernouilli equation correlated poorly with the measured translesional gradient (r = 0.27, F = 1.63, p = 0.21).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7732977

Kern, M J; Tron, C; Donohue, T J; Bach, R G; Caracciolo, E A; Aguirre, F V; Labovitz, A J

1995-05-01

139

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

140

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

Science.gov (United States)

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

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

2014-04-01

141

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

Science.gov (United States)

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.

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

2008-03-01

142

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

Science.gov (United States)

As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts. PMID:24098649

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

2013-01-01

143

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

144

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

145

Vapor bubbles 'SUMO'  

CERN Document Server

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

Hosoya, Ryota

2010-01-01

146

Stratospheric water vapor feedback  

OpenAIRE

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

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

2013-01-01

147

40 CFR 52.246 - Control of dry cleaning solvent vapor losses.  

Science.gov (United States)

...2010-07-01 false Control of dry cleaning solvent vapor losses. 52.246...California § 52.246 Control of dry cleaning solvent vapor losses. (a) For the purpose of this section, “dry cleaning operation” means that...

2010-07-01

148

Carbonate mineral dissolution and the impacts of flood water exchange between conduit and matrix  

Science.gov (United States)

Studies of flow and dissolution in karst aquifers have traditionally focused on conduits, and contributions from matrix sources have been generally ignored. This conceptual model works for limestone that has been deeply buried and had its matrix permeability obliterated by cementation (telogenetic) so that most aquifer recharge occurs by conduits. In limestone that has not been deeply buried (eogenetic), however, high matrix permeability is preserved, resulting in greater degrees of interaction between conduit and matrix porosity than occurs in telogenetic limestone. Interactions between conduit and matrix porosity, and how these interactions affect flow and dissolution within aquifers, is particularly important in karst aquifers subject to dynamic changes in head gradients between conduits and aquifers. These exchanges are particularly prevalent in transitional areas between confined and unconfined aquifer conditions. In such transitional areas, allogenic runoff from confining units can increase river stages on adjacent unconfined aquifers faster than infiltration of local rainfall can increase groundwater heads. As a result, normal hydraulic gradients between the aquifer and rivers are reversed, causing river water to flow into springs. Simultaneously, rapid increases in conduit hydraulic head will also reverse gradients between the conduit and the aquifer, driving exchange from the conduit to the matrix. Because allogenic runoff is highly undersaturated with respect to calcite after storm events, dissolution resulting from this exchange can be extensive. The magnitude of dissolution that occurs is a function of the calcite saturation state of the allogenic runoff, the surface area of the limestone in contact with the water, and the time that water remains in contact with the limestone. In eogenetic aquifers, the magnitude of dissolution that occurs during spring reversals should be higher than in telogenetic aquifers because of their elevated matrix permeabilities, which allows for both greater volumes of water exchange and greater mineral surface area. Quantitative comparisons of the dissolution in eogenetic and telogenetic karst aquifers have not hitherto been made. We present the results of modeling experiments that compare the magnitude amount of dissolution that would occur as a result of spring reversals in telogenetic and eogenetic settings. Water fluxes and residence times were calculated using MODFLOW and Conduit Flow Processes (CFP) and dissolution was estimated using PHREEQC geochemical modeling software. Maximum aquifer residence times of allogenic runoff were twice as long in telogenetic aquifers , but because most water was restricted to the conduit, dissolution was limited. Volumes of exchange and dissolution in eogenetic settings were orders of magnitude higher.

Spellman, P.; Screaton, E.; Gulley, J. D.; Martin, J. B.

2012-12-01

149

Well tool with sealing means  

International Nuclear Information System (INIS)

This patent describes a downhole well tool securable to tubular members for forming a section of a cylindrical fluid flow conduit within the well and for selective transmission of fluids therethrough between the interior and the exterior of the tool. It comprises: a housing; first and section threaded ends for securing the housing between companion ends of the tubular members; a fluid communication port disposed through the housing and between the threaded ends; one of the threaded ends being upstream of the port and the other of the threaded ends being downstream of the port; sealing means interiorly positioned around each of the tubular members and having a face in abutting relationship with the housing; a sleeve disposed interiorly of the housing; a closed position with the seal means disposed in a substantially enclosed region; and an open position with the seal means

150

Vapor bubbles 'SUMO'  

OpenAIRE

We carry out a series of experiments with a special interest on growing and condensing processes of vapor bubble(s) injected into a subcooled pool. We examine effects of the degree of subcooling of the bulk in the pool and injection rate of the vapor into the pool. We pay their special attention to (i) abrupt collapse of the injected vapor bubble to form micrometer-scale bubbles, and (ii) interaction of adjacent vapor bubbles laterally injected to the pool through the orific...

Hosoya, Ryota; Ueno, Ichiro

2010-01-01

151

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

152

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

153

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

Directory of Open Access Journals (Sweden)

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

154

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

155

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend  

Science.gov (United States)

A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Ortiz, Marcos German (Idaho Falls, ID)

1998-01-01

156

Numerical Simulation of The Coupled Conduit and Atmospheric Dispersal Dynamics of The 4400 Bp Agnano Monte Spina Trachitic Eruption, Phlegrean Fields  

Science.gov (United States)

The Phlegrean Fields Caldera (PFC), close to Naples, has a very high destructive po- tential in case of activity renewal. We have simulated the coupled dynamics of magma ascent and pyroclast dispersal in the atmosphere of the 4400 BP Agnano Monte Spina eruption, which represents the highest intensity event of the last cycle of activity at PFC. Two sustained magmatic phases of the eruption, corresponding to layers B1 and D1 (De Vita et al., 1999), were selected for the simulations. Boundary conditions for the simulation of the steady phases of magma ascent in the conduit, as well as relevant magma properties, are taken from the literature and from recent results of a coordi- nated project sponsored by the Italian Gruppo Nazionale per la Vulcanologia, devoted to the determination of the eruption dynamics during relevant eruptive events at PFC. Each simulated eruptive phase is assigned a range of mass flow-rate in order to account for uncertainties in the reconstructions. The mass flow-rate of phase B1 ranges from 2.5x10^7 to 10^8 kg/s, that of phase D1 from 5 to 1.8x10^8 kg/s. Water contents were parameterized and allowed to vary from 2 to 6 wt%, and volatiles other than water were neglected. The simulations of conduit flow dynamics were carried out by means of a multiphase flow model previously developed (Papale, 2001), and show a substan- tial increase of pressure distribution in the conduit from the B1 to the D1 phase of the eruption, and within each phase, with increasing assumed mass flow-rate. The depth of fragmentation also increases by 1000-1500 m from phase B1 to D1. Calculated conduit diameters range from 50 to 130 m for phase B1, and from 65 to 150 m for phase D1, depending on the assumed mass flow-rate and water content. From phase B1 to D1, at equal water content, the conduit exit gas volume fraction, gas and particle velocity tend to slightly decrease, while exit pressure and mixture density tend to in- crease. Conduit exit conditions computed by the magma ascent modeling were used as boundary conditions for the simulation of the transient two- dimensional multiphase dynamics of gas/pyroclast dispersal in the atmosphere (Neri et al. 2001). The results show that within each eruptive phase a fourfold variation of the mass flow-rate, and associated changes of conduit diameter and conduit exit conditions, do not result in 1 significant variations of the eruptive style. On the contrary, the eruptive style is very sensitive to changes in the assumed water content. For both phases a water content of 2 to 4 wt% results in a dominantly collapsing volcanic column, whereas a water content of 6 wt% results in a dominantly convective column, with small or negligible partial collapses from its margins, mainly related to the transient dynamics during the very initial eruptive phase. The best comparison between simulation results and the eruptive dynamics reconstructed from the stratigraphy is obtained for the higher water contents. References De Vita, S., et al., 1999. J. Volcanol. Geotherm. Res., 91:269-301. Neri, A., et al., 2001. VSG Report 2001-2, ETS Editori Pisa, and J. Geophys. Res. (sub judice). Pa- pale, P., 2001. J. Geophys. Res., 106 : 11,043-11,065. 2

Papale, P.; Neri, A.; del Seppia, D.; Esposti Ongaro, T.

157

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

158

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)

159

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

Science.gov (United States)

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

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

2014-04-01

160

Piezoelectric trace vapor calibrator  

International Nuclear Information System (INIS)

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

161

Piezoelectric trace vapor calibrator  

Science.gov (United States)

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

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

2006-08-01

162

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

163

Transverse colon conduit urinary diversion in patients treated with very high dose pelvic irradiation  

Energy Technology Data Exchange (ETDEWEB)

Urinary diversion may be required in patients receiving pelvic irradiation for gynaecological or genitourinary cancers either as part of a planned or salvage surgical procedure or for urological complications of irradiation. Records were reviewed for 30 such patients who underwent transverse colon conduit as a primary form of urinary diversion. Most of the conduits were constructed using refluxing ureterocolic anastomoses with stents. The results showed no operative mortality. Although the procedure was associated with a complication rate of 37% and a re-operation rate of 20%, there were no bowel or urinary anastomotic leaks. The operation could be safely performed on patients with renal failure, with 83% of such patients showing normal or improved serum creatinine levels post operatively. The advantages of transverse colon conduit urinary diversion are the use of non-irradiated bowel and ureters for diversion. It is recommended as a primary form of urinary diversion in these high risk cases. (Author).

Ravi, R.; Dewan, A.K. (Cancer Inst. (WIA), Adyar, Madras (India)); Pandey, K.K. (Safdarjang Hospital, New Delhi (India))

1994-01-01

164

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

International Nuclear Information System (INIS)

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

165

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

166

Modeling magma flow in volcanic conduit with non-equilibrium crystallization  

Science.gov (United States)

Modeling magma flow in volcanic conduit including with non -equilibrium crystallization There is a set of models of magma flow in volcanic conduits which predicts oscillations in magma discharge during extrusion of lava domes. These models neglect heating of surrounding rocks and use 1D approximation of the flow in the conduit. Here magma flow is investigated with an account of heat exchange between surrounding rocks and magma and different dependences viscosity on temperature and crystal concentration. Stick-slip conditions were applied at the wall. The flow is assumed to be quasi-static and quasi 1D. Only vertical component of velocity vector is present, thus, we do not consider horizontal momentum balance. At the top of the conduit the pressure is assumed to be fixed, chamber pressure changes according with magma influx and outflux. First set of simulation was made for the viscosity that depends on cross-section average crystal concentration and parabolic velocity profile. In earlier models that account for crystal growth kinetics the temperature was allowed to change only due to the release of latent heat of crystallization. Heat transfer leads to cooling of the outer parts of the conduit leading to high crystal contents and high magma viscosities. Changes in viscosity result in changes in discharge rate. For the non-isothermal case there is no motion during most part of the cycle and a portion of magma solidifies at the top of the conduit forming a plug. During repose period chamber pressure is growing due to influx of fresh magma, and magma discharge rate starts to increase. Influx of hot magma into the conduit leads to decrease in friction resulting in a jump in discharge rate that lead to depressurization of magma chamber. Discharge rate decreases and magma solidifies again. For isothermal model with the same parameters discharge rate monotonically tends to the value of Qin. Simulation reveal that crystal content changes significantly across the conduit, and thus viscosity variations across the conduit are large. A more comprehensive model was developed to account for cross-conduit parameter distributions. It shows that velocity profile significantly differ from parabolic especially near the top of the conduit where slip condition s occurs. References 1. A.Barmin, O.Melnik, R.S.J.Sparks, Periodoc behavior in lava dome eruptions, Earth and Planetary Science Letters 199(2002) 173-184 2. P.M.Bruce, H.E.Huppert, Thermal control of basaltic fissure eruptions, 1989, Letters To Nature, VOL 342 3. I.Maeda, Nonlinaer visco-elastic volcanic model and its application to the recent eruption of Mt.Unzen, 2000, Journal of Volcanology and Geothermal Research, 95, 35-47 4. J.A.Whitehead, K.R.Helfrich, Instability of flow with temperature dependent viscosity: a model of magma dynamics, 1991, Journal of Geophysical Research, VOL 96, No B3, pages 4145-4155 5. A.Costa, G.Macedonio, Nonlinear phenomena in fluids with temperature-dependent viscosity: an hysteresis model for magma flow in conduits, 2002, Geophysical Research Letters, VOL 29, No 10, 1402 6. Richard Iverson Dynamics of Seismogenic Volcanic Extrusion Re¬sisted by a Solid Surface Plug, Mount St. Helens, 2004-2005, A Volcano Rekindled: The First Year of Renewed Eruption at Mount St. Helens, 2004-2006. 7. Couch, S., C. L. Harford, R. S. J. Sparks, and M. R. Carroll (2003),Experimental constraints on the conditions of formation of highly calcic plagioclase microlites at the Soufrie`re Hills Volcano, Montserrat, J. Petrol.,44, 1455- 1475.

Yulia, Tsvetkova

2010-05-01

167

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

168

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

Directory of Open Access Journals (Sweden)

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

U. Lauber

2013-09-01

169

Fractures as Advective Conduits at the Earth Atmosphere Interface  

Science.gov (United States)

Understanding gas exchange between the Earth's upper crust and the atmosphere is vital and necessary because this phenomenon controls to a large extent many important processes including, the water cycle, agricultural activities, greenhouse gas emissions and more. From a hydrological aspect, water vapor transport is an extremely important process related to Earth-atmosphere gas exchange because it affects above ground water vapor concentration, soil water content and soil salinity. Traditionally, diffusion was considered the main mechanism of gas exchange between the atmosphere and vadose zone, driven by gas concentration gradients. While this assumption may be correct for many porous media, our laboratory and field-scale studies have shown that advective gas transport mechanisms are governing these fluxes in fractured rocks and cracked soils. Convection driven by thermal gradients (free convection) and wind induced (forced convection) were explored and both were found to play a major role in Earth-atmosphere gas exchange. Long-term laboratory experiments using fracture simulators in a customized climate controlled laboratory have shown that thermal convection occurs when nighttime thermal conditions prevail. This convective venting significantly enhances evaporation and subsequently salt precipitation on the fracture walls. Experiment results were used to develop an empirical relationship between temperature gradients, fracture aperture and convective gas flux through the fracture. Theoretical calculations show that thermal convection is indeed likely to play a major role in evaporation from fractures and can explain enhanced salt accumulation observed in surface-exposed fractures. Long-term field measurements, carried out continuously for 5+ years in a single fracture in the Israeli Negev Desert, verified the development of air convection cycles of 10-18 hours duration on a daily basis, with a peak in both convective flux and duration during the winter. During winter, the nighttime thermal gradient is at its yearly maximum. In addition to thermally driven convection, wind-induced convection was quantified in the laboratory and an empirical equation was developed that links wind speed, fracture aperture and resulting convection depth. Concurrent field data demonstrated the important role of wind in gas exchange through fractures under natural conditions. Overall, these multi-scale laboratory and field observations strongly suggest that fractures and cracks, crossing the Earth-atmosphere interface, need to be included in predictive models where gas transport across this critical interface is being explored and quantified.

Dragila, M. I.; Weisbrod, N.; Nachshon, U.; Kamai, T.

2012-12-01

170

The Bentall procedure with a biological valved conduit: substitute options and techniques.  

Science.gov (United States)

As originally described by Bentall and De Bono, aortic root replacement with reimplantation of the coronary arteries using a composite valved conduit represents the gold standard intervention in patients with aneurysmal disease or dissection involving the aortic root. Over the last decade, the number of Bentall procedures performed using biological valved conduit has dramatically expanded mainly due to the increased incidence of aortic disease in the aging population. Here, we sought to describe the commercially available biological composite grafts and the techniques that, to the best of our knowledge, are most frequently used in this setting. PMID:24925908

Di Eusanio, Marco; Murana, Giacomo; Cefarelli, Mariano; Mazzola, Alessandro; Di Bartolomeo, Roberto

2014-01-01

171

Small scale high resolution LiDAR measurements of a subglacial conduit  

Science.gov (United States)

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

Mankoff, K. D.; Gulley, J.

2012-04-01

172

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.

173

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

174

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)

175

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

176

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

177

Directed vapor deposition  

Science.gov (United States)

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

Groves, James Frederick

178

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

Science.gov (United States)

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

Vanobbergen, Bruno; Grosvenor, Ian; Simon, Frank

2014-01-01

179

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

180

Fibreoptic intubation using three airway conduits in a manikin: the effect of operator experience.  

Science.gov (United States)

In a randomised cross-over study, 72 anaesthetists (24 Senior House Officers, 24 Specialist Registrars and 24 Consultants) attempted to place a fibreoptic scope in the trachea of a manikin using three airway conduits: the Berman airway, the LMA Classic(trade mark) and the intubating laryngeal mask airway. The time for insertion of the airway conduit, delivery of two breaths and fibreoptic scope placement in the trachea was the primary endpoint. These overall times were significantly shorter (median [interquartile range]) using the LMA Classic (36 [28-45]) than via the intubating laryngeal mask (54 [42-79]) and the Berman airway (45 [33-80]), p < 0.0001. Senior House Officers were significantly slower than both Specialist Registrars and Consultants (p < 0.0001). The LMA Classic was considered to be the easiest conduit to use for fibreoptic scope placement by all grades of anaesthetists. We conclude that the LMA Classic is the most effective conduit for fibreoptic scope placement especially for anaesthetists with limited experience in its use. PMID:17506738

Hodzovic, I; Petterson, J; Wilkes, A R; Latto, I P

2007-06-01

181

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

Science.gov (United States)

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

Nzegwu, Azuka

2010-01-01

182

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

Science.gov (United States)

Heart valve disease is a serious and growing public health problem for which prosthetic replacement is most commonly indicated. Current prosthetic devices are inadequate for younger adults and growing children. Tissue engineered living aortic valve conduits have potential for remodeling, regeneration, and growth, but fabricating natural anatomical complexity with cellular heterogeneity remain challenging. In the current study, we implement 3D bioprinting to fabricate living alginate/gelatin hydrogel valve conduits with anatomical architecture and direct incorporation of dual cell types in a regionally constrained manner. Encapsulated aortic root sinus smooth muscle cells (SMC) and aortic valve leaflet interstitial cells (VIC) were viable within alginate/gelatin hydrogel discs over 7 days in culture. Acellular 3D printed hydrogels exhibited reduced modulus, ultimate strength, and peak strain reducing slightly over 7-day culture, while the tensile biomechanics of cell-laden hydrogels were maintained. Aortic valve conduits were successfully bioprinted with direct encapsulation of SMC in the valve root and VIC in the leaflets. Both cell types were viable (81.4 ± 3.4% for SMC and 83.2 ± 4.0% for VIC) within 3D printed tissues. Encapsulated SMC expressed elevated alpha-smooth muscle actin, while VIC expressed elevated vimentin. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting. PMID:23015540

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

2013-05-01

183

A boiling heat transfer surface for creating a single stream of vapor bubbles.  

Science.gov (United States)

The high heat transfer rate characteristic of boiling is limited by the vapor-bubble removal rate and a critical transition to film boiling. External forces, such as acoustic waves, can be used to enhance vapor-bubble removal and improve heat transfer. In order to explore such enhanced vapor-bubble removal processes, a boiling heat transfer surface has been designed to control the location, growth, and detachment of a single stream of vapor bubbles. The device consists of an insulating annulus surrounding a thermally conductive pin 1 mm in radius. The upper surfaces of the annulus and the pin have a thin polished electro-plated copper coating. When heated from below, the pin provides a thermal conduit that creates a local hot spot on the copper surface. The majority of all bubble nucleations occur within 3 mm of the center of the pin. A thin hydrophobic coating centered on the hot spot encourages the formation of a single vapor bubble that grows to a size determined by the radius of the hydrophobic coating. When the bubble detaches from the surface, a new vapor bubble forms in the same location. High-speed video and bubble-size and thermal measurements will be presented to document the characteristics and performance of this heat transfer surface.

Douglas, Zachary W.; Smith, Marc K.; Glezer, Ari

2006-11-01

184

Monolithic microwave integrated circuit water vapor radiometer  

Science.gov (United States)

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

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

1991-01-01

185

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

Science.gov (United States)

A manufacturing process for fabricating off-the-shelf multilumen poly(ethylene glycol) (PEG)-based nerve guidance conduits (NGCs) was developed that included the use of stereolithography (SL). A rapid fabrication strategy for complex 3D scaffolds incorporated postprocessing with lyophilization and sterilization to preserve the scaffold, creating an implantable product with improved suturability. SL is easily adaptable to changes in scaffold design, is compatible with various materials and cells, and can be expanded for mass manufacture. The fabricated conduits were characterized using optical and scanning electron microscopy, and measurements of swelling ratio, dimensional swelling factor, resistance to compression, and coefficient of friction were performed. Water absorption curves showed that the conduits after lyophilization and sterilization return easily and rapidly to a swollen state when placed in an aqueous solution, successfully maintaining their original overall structure as required for implantation. Postprocessed conduits at the swollen state were less slippery and therefore easier to handle than those without postprocessing. Suture pullout experiments showed that NGCs fabricated with a higher concentration of PEG were better able to resist suture pullout. NGCs having a multilumen design demonstrated a better resistance to compression than a single-lumen design with an equivalent surface area, as well as a greater force required to collapse the design. Conduits fabricated with a higher PEG concentration were shown to have compressive resistances comparable to those of commercially available NGCs. The use of SL with PEG and the manufacturing process developed here shows promise for improving the current state of the art in peripheral nerve repair strategies. PMID:20673135

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

2011-01-01

186

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

187

The Meaning of Meaning, Etc.  

Science.gov (United States)

This paper attempts to dispel a number of misconceptions about the nature of meaning, namely that: (1) synonyms are words that have the same meanings, (2) antonyms are words that have opposite meanings, (3) homonyms are words that sound the same but have different spellings and meanings, (4) converses are antonyms rather than synonyms, (5)…

Nilsen, Don L. F.

188

Electrolyte vapor condenser  

Science.gov (United States)

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

Sederquist, Richard A. (Newington, CT); Szydlowski, Donald F. (East Hartford, CT); Sawyer, Richard D. (Canton, CT)

1983-01-01

189

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

190

Preservation of systemic tricuspid valve function by pulmonary conduit banding in a patient with corrected transposition of the great arteries  

Science.gov (United States)

Systemic tricuspid valve regurgitation increases mortality and morbidity in patients with a corrected transposition of the great arteries. A 17-year old male with a physiologically corrected transposition after the closure of a ventricular septal defect and conduit placement between a morphological left ventricle and pulmonary artery presented with exertional dyspnoea. The transthoracic echocardiography showed a severe conduit stenosis, and cardiac catheterization revealed a pressure gradient of 114 mmHg. The patient underwent conduit re-replacement using a pulmonary heterograft. Intraoperative transoesophageal echocardiography revealed an acute severe tricuspid regurgitation after a conduit re-replacement. Pulmonary conduit banding was performed under transoesophageal echocardiography guidance, during which the left ventricular to right ventricular pressure ratio increased from 0.33 to 0.60 and the degree of tricuspid regurgitation decreased mildly. The patient was discharged uneventfully at postoperative day 16. Conduit banding might be a useful technique to preserve the systemic tricuspid valve function during conduit re-replacement in patients with a corrected transposition. PMID:22572412

Erek, Ersin; Abud, Burcin; Oz, Kursad; Güzeltas, Alper

2012-01-01

191

Water vapor in protoplanetary disks  

Science.gov (United States)

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

Banzatti, Andrea

2013-03-01

192

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

Science.gov (United States)

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

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

2011-01-01

193

Constraints on the Geometries and Compositions of Subvolcanic Conduits from Intrusions of the San Rafael Swell, Utah  

Science.gov (United States)

Conduit models incorporate varying degrees of complexity (or parsimony) and account for the transport properties of magmas, steady-state or transient behavior, and conduit geometry (e.g., 1- to 1.5 D, variable width and erodable conduit walls). Improvement of these models is important if we are to work toward deployment of eruption models at active volcanoes, link these models to geophysical observations (seismic, deformation, gravity) and eventually forecast eruption magnitude. One conclusion of a recent comparison of many conduit models (Sahagian, 2005 JVGR) is that next generation models need to better account for interaction of the erupting mixture with surrounding wall rocks (accounting for melting, solidification, and erosion) and better account for the effects of conduit shape on flows. In an effort to address these issues our research group has completed mapping of a suite of subvolcanic intrusions (dikes, sills, and conduits) from the west-central San Rafael Swell of central Utah. The results of this study demonstrate that vertical flow of melt through crust in this system of intrusion was dominated by dikes. Conduits form, in nearly all cases, as a result of localized flow along dikes. The conduits are commonly comprised of three distinct lithologic units: brecciated host rock (without any intrusive material), brecciated host rock mixed with brecciated and mechanically contaminated intrusive, and relatively clean (i.e. containing less than ~10% accidental material) intrusive. Contacts between all three of these units are typically discreet and traceable for several tens of meters. In some examples clasts within the unmixed breccia unit exhibit a strong alignment of clasts dipping into the core of the conduit. These observations suggests an evolutionary history that involves an early phase of brecciation and mixing, followed by confined flow with a fluidized mixed unit and an essentially uninvolved outer zone (i.e. the breccia). The final phase likely involves the inward collapse as fluid pressures reduce.

Wetmore, P. H.; Connor, C.; Wilson, J.

2010-12-01

194

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus  

Science.gov (United States)

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

195

33 CFR 154.828 - Vapor recovery and vapor destruction units.  

Science.gov (United States)

... false Vapor recovery and vapor destruction... POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor...154.828 Vapor recovery and vapor destruction...or mooring at the facility; (2)...

2010-07-01

196

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

Science.gov (United States)

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

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

2012-06-01

197

A case of fatal septic pulmonary embolus arising from an infected Sano conduit.  

Science.gov (United States)

A 5-month-old boy who had previously undergone a modified Norwood procedure for hypoplastic left heart syndrome presented for elective cardiac catheterization before undergoing the next stage of repair. The catheterization demonstrated mild stenosis of the right ventricle-to-pulmonary artery Sano conduit. The patient became hypoxic and febrile at the end of the procedure and died in the intensive care unit the next day. Postmortem examination demonstrated a vegetation containing Gram-positive cocci in the conduit and a right upper lobe lung abscess also containing Gram-positive cocci. The authors report the first case of Sano shunt endocarditis further complicated by septic pulmonary embolus and review similar infections in this population. Shunt infection may be an underrecognized cause of interstage mortality among patients undergoing a modified Norwood procedure. PMID:18654812

Mahar, Tara; Katzman, Philip; Alfieris, George

2009-02-01

198

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

CERN Document Server

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

Sochi, Taha

2014-01-01

199

Glycol still column vapor emissions  

International Nuclear Information System (INIS)

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

200

Possible Conduit-Matrix Water Exchange Signatures Outlined at a Karst Spring.  

Science.gov (United States)

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

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

2014-11-12

201

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

OpenAIRE

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

202

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

Science.gov (United States)

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

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

2014-07-01

203

Large bifid ureteric calculus in a patient with an ileal conduit  

OpenAIRE

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

Rajaian, Shanmugasundaram; Kekre, Nitin S.

2012-01-01

204

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

OpenAIRE

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

205

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

OpenAIRE

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

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

2011-01-01

206

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

207

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

OpenAIRE

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

208

Oesophageal Conduit – a Cause of Diffuse Mediastinal Uptake on Thyroid Scintigraphy  

OpenAIRE

99mTc-pertechnetate scintigraphy plays an essential role in the management of a variety of thyroid and parathyroid disorders. The authors report an unusual case of mediastinal tracer distribution of 99mTc-pertechnetate and 99mTc-MIBI in relation to an oesophageal conduit following oesophago-gastrectomy and reconstructive surgery on thyroid scintigraphy. This is a rare but important cause of diffuse mediastinal uptake on thyroid scintigraphy. An awareness of abnormal anatomy as well as altered...

Sonoda, Luke I.; Balan, Kottekkattu K.

2013-01-01

209

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

Scientific Electronic Library Online (English)

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 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

210

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

International Nuclear Information System (INIS)

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

211

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

Science.gov (United States)

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

Yoshida, Kiyoshi; Takigami, Hiroyuki; Kubo, Hiroatsu

2001-08-01

212

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

Science.gov (United States)

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

Rajaian, Shanmugasundaram; Kekre, Nitin S

2012-09-01

213

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

214

The Norwood procedure: in favor of the RV-PA conduit.  

Science.gov (United States)

Evolution of the Norwood procedure has culminated in there currently being three treatment strategies available for initial management: the 'classical' Norwood (utilizing a Blalock-Taussig shunt), the Norwood with right-ventricle to pulmonary artery (RV-PA) conduit, and the 'hybrid' Norwood procedure utilizing bilateral pulmonary artery banding and ductal stenting. Each variant has its potential advantages and disadvantages, and this paper looks to examine the evidence in favor of each strategy, with emphasis on the supportive data for the RV-PA conduit. The 'classical' procedure has the benefit of the greatest accumulated surgical experience and avoids any incision into the ventricle. However, the diastolic run-off of the Blalock-Taussig shunt can cause hemodynamic instability and unpredictable coronary steal phenomenon. The RV-PA conduit has the advantage of maintaining diastolic pressure with a more stable postoperative course, but at the cost of a ventriculotomy that may have detrimental long-term sequelae. The 'hybrid' procedure has the advantage of avoiding cardiopulmonary bypass, but does not always secure coronary blood flow and has a high inter-stage morbidity and reintervention rate. The evidence shows that each technique may have its place in future management, and that treatment algorithms could emerge that direct the choice of procedure for specific patient groups. PMID:23561818

Barron, David J

2013-01-01

215

75 FR 44982 - Arkansas Valley Conduit (AVC) and Long-Term Excess Capacity Master Contract, Fryingpan-Arkansas...  

Science.gov (United States)

...of Reclamation Arkansas Valley Conduit (AVC) and Long-Term Excess Capacity Master...effects associated with construction of the AVC, a proposed feature of the Fryingpan-Arkansas...of interest. Background Information The AVC, an authorized feature of the...

2010-07-30

216

Nerve Guidance Conduits from Aligned Nanofibers: Improvement of Nerve Regeneration through Longitudinal Nanogrooves on a Fiber Surface.  

Science.gov (United States)

A novel fibrous conduit consisting of well-aligned nanofibers with longitudinal nanogrooves on the fiber surface was prepared by electrospinning and was subjected to an in vivo nerve regeneration study on rats using a sciatic nerve injury model. For comparison, a fibrous conduit having a similar fiber alignment structure without surface groove and an autograft were also conducted in the same test. The electrophysiological, walking track, gastrocnemius muscle, triple-immunofluorescence, and immunohistological analyses indicated that grooved fibers effectively improved sciatic nerve regeneration. This is mainly attributed to the highly ordered secondary structure formed by surface grooves and an increase in the specific surface area. Fibrous conduits made of longitudinally aligned nanofibers with longitudinal nanogrooves on the fiber surface may offer a new nerve guidance conduit for peripheral nerve repair and regeneration. PMID:25786058

Huang, Chen; Ouyang, Yuanming; Niu, Haitao; He, Nanfei; Ke, Qinfei; Jin, Xiangyu; Li, Dawei; Fang, Jun; Liu, Wanjun; Fan, Cunyi; Lin, Tong

2015-04-01

217

Vapor explosion phenomena: Scaling considerations  

International Nuclear Information System (INIS)

Past safety analyses considered the hazard from vapor explosions in a conservative manner where engineering judgment and conservative analyses were used to estimate the likelihood of nuclear reactor containment failure from explosion-induced missile generation [alpha-mode failure]. However, recent safety analyses may require less conservative methods to determine the hazard from vapor explosions; thus one may need to consider more detailed scaling of vapor explosion phenomena. This paper proposes particular scaling considerations for vapor explosions based on recent experimental results and that vapor explosions with prototypic reactor fuel material may be less of a hazard

218

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

OpenAIRE

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. Electrosp...

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

2011-01-01

219

Preservation of systemic tricuspid valve function by pulmonary conduit banding in a patient with corrected transposition of the great arteries  

OpenAIRE

Systemic tricuspid valve regurgitation increases mortality and morbidity in patients with a corrected transposition of the great arteries. A 17-year old male with a physiologically corrected transposition after the closure of a ventricular septal defect and conduit placement between a morphological left ventricle and pulmonary artery presented with exertional dyspnoea. The transthoracic echocardiography showed a severe conduit stenosis, and cardiac catheterization revealed a pressure gradient...

Erek, Ersin; Abud, Burcin; Oz, Kursad; Gu?zeltas, Alper

2012-01-01

220

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

221

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

OpenAIRE

Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. As a consequence, this system may show an hysteresis effect, and the transition between the two branches can occur quick...

Costa, Antonio; Macedonio, Giovanni

2003-01-01

222

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

Science.gov (United States)

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

Sun, Jielun

1993-01-01

223

The vapor pressures of explosives  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-01-05

224

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.

225

Using ballistic bombs at Pichincha volcano, Ecuador as a proxy for conduit dynamics in Vulcanian eruptions  

Science.gov (United States)

Vulcanian eruptions are perhaps the most common style of eruptive activity at intermediate composition volcanoes, as they often precede and/or follow much larger Plinian events. Vulcanian eruptions occur in energetic, short-duration pulses and eject relatively small amounts of material. However, although each pulse has been inferred to represent the ejection of a shallow conduit plug, the dynamics and mechanics of vulcanian eruptions are not well understood; the character of the material that is ejected, the amount of erupted material, the pressurization conditions preceding eruption, and the maximum depth that these eruptions tap are unresolved questions. To address conditions leading to Vulcanian eruptions, we are studying ballistic bombs ejected from the 1999-2000 vulcanian eruptions at Guagua Pichincha volcano, Ecuador. Bomb types range from dense to highly vesicular, with many exhibiting the breadcrusting that is ubiquitous in Vulcanian deposits. Clast morphology varies with clast density, with slightly vesicular bombs having thick, glassy crusts with widely spaced cracks, while more vesicular bombs have thinner crusts and more closely spaced crack patterns. We suggest that the wide range of clast types may represent the stratigraphy of the uppermost conduit prior to each eruptive event, with denser blocks representing more degassed magma from near the top of the pre-eruptive conduit plug and more vesicular blocks representing deeper, less degassed levels in the conduit. Quantification of both the breadcrust crack structures (e.g. crack orientation, density of the rind, and crack spacing) and the interior porosity and permeability of each bomb type allows us to examine the thermal, vesiculation and expansion history of the erupted material. Different breadcrust types experienced variable degrees of expansion. For example, the volume expansion of the most vesicular clast is ~6% based on the relationship between crack volume and total bomb volume, whereas the volume expansion of the densest clast is over 23%. Comparison of interior and exterior vesicularities suggests that a permeable network may have formed to allow escape of volatiles from the interior of the bombs, after the initial cracks formed. Additionally, several bombs preserve different breadcrusting styles on different bomb faces. These unusual bombs may have formed an initial surface fracture set before impacting the ground, at which time they split into 2 pieces and subsequently formed a separate fracture pattern on the newly exposed surface. These different patterns suggest varied cooling histories for each phase of the eruption, supporting the inference that vesiculation continued after emplacement. These ballistic bombs thus provide an opportunity to look at the pre-eruptive stratigraphy and ejection history of conduit material in a Vulcanian eruption.

Wright, H.; Rosi, M.; Cioni, R.; Cashman, K.

2003-04-01

226

A stability analysis of a conduit flow model for lava dome eruptions  

Science.gov (United States)

Periodic variations in magma discharge rate and ground deformation have been commonly observed during lava dome eruptions. We performed a stability analysis of a conduit flow model by Barmin et al. [Barmin, A., Melnik, O., Sparks, R.S.J., 2002. Periodic behavior in lava dome eruptions. Earth and Planetary Science Letters 199 (1-2), 173-184], in which the periodic variations in magma flow rate and chamber pressure are reproduced as a result of the temporal and spatial changes of the magma viscosity controlled by the kinetics of crystallization. The model is reduced to a dynamical system where the time derivatives of the magma flow rate ( dQ/ dt) and the chamber pressure ( dP/ dt) are functions of Q and P evaluated at a shifted time t - t *. Here, the time delay t* represents the time for the viscosity of fluid particle to increase in a conduit. The dynamical system with time delay is approximated by a simple two-dimensional dynamical system of Q and P where t* is given as a parameter. The results of our linear stability analyses for these dynamical systems indicate that the transition from steady to periodic flow depends on nonlinearities in the steady state relation between Q and P. The steady state relation shows a sigmoidal curve in Q - P phase plane; its slope has negative values at intermediate flow rates. The steady state solutions become unstable, and hence P and Q oscillate periodically, when the negative slope of the steady state relation ([ dP/ dQ] S) exceeds a critical value; that is [ dP/ dQ] S < - t*?/(2 Vch), where Vch is the chamber volume and ? is an elastic constant which is related to the rigidity of chamber wall. We also found that the period and the pattern of oscillation of the conduit flow primarily depend on a quantity defined by LVch/ r4, where L is the conduit length and r is the conduit radius.

Nakanishi, M.; Koyaguchi, T.

2008-11-01

227

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

Science.gov (United States)

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

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

2010-12-01

228

Covering sources of toxic vapors with foam  

International Nuclear Information System (INIS)

In a case of chemical terrorism, first responders might well be confronted with a liquid source of toxic vapor which keeps spreading out its hazardous contents. With foam as an efficient and simple means, such a source could be covered up in seconds and the spread of vapors mitigated drastically. Once covered, the source could then wait for a longer time to be removed carefully and professionally by a decontamination team. In order to find foams useful for covering up toxic vapor sources, a large set of measurements has been performed in order to answer the following questions: - Which foams could be used for this purpose? - How thick should the foam cover be? - For how long would such a foam cover be effective? - Could the practical application of foam cause a spread of the toxic chemical? The toxic vapors sources included GB, GD and HD. Among the foams were 10 fire fighter foams (e.g. AFFF, protein) and the aqueous decontamination foam CASCAD. Small scale experiments showed that CASCAD is best suited for covering a toxic source; a 10 cm layer of it covers and decontaminates GB. The large scale experiments confirmed that any fire fighter foam is a suitable cover for a longer or shorter period.(author)

229

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.

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

2015-02-01

230

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

231

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

232

How Mean is the Mean?  

OpenAIRE

In this paper we voice concerns about the uncritical manner in which the mean is often used as a summary statistic in psychological research. We identify a number of implicit assumptions underlying the use of the mean and argue that the fragility of these assumptions should be more carefully considered. We examine some of the ways in which the potential violation of these assumptions can lead us into significant theoretical and methodological error. Illustrations of alternative models of rese...

CraigSpeelman; MarekMcGann

2013-01-01

233

Vapor Diffusion Apparatus  

Science.gov (United States)

Vapor Diffusion Apparatus (VDA-2) was developed by the University of Alabama in Birmingham for NASA's Marshall Space Flight Center. In the original VDA, a protein solution and a precipitant are extruded by two plungers onto the tip of a small syringe and allowed to evaporate, raising the concentration and prompting protein molecules to crystallize. In the VDA-2 version, a third plunger was added to mix the two solutions before returning the mix to the syringe tip. The principal investigator is Dr. Larry Delucas of the University of Alabama in Birmingham.

2001-01-01

234

Optimization of JK2LB chemical composition for ITER Central Solenoid conduit material  

Science.gov (United States)

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

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

2007-03-01

235

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

236

Program CICC: Flow and heat transfer in Cable In Conduit Conductors, user's manual  

Science.gov (United States)

This report is the user's manual for program CICC and it's graphics postprocessor, CICCP. CICC was written for use in the thermofluids design of the cryogenic superconducting magnets which utilize helium-cooled, cable-in-conduit conductors (CICC). The program models the transient thermodynamic and fluid-dynamic system response to the occurrence of normal-zone heating in the superconductor. References 1 and 2 have previously been written describing the equations used in the program, the solution method, and the experimental verification.

Wong, Robert L.

1990-02-01

237

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

Science.gov (United States)

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

Moore, Karen A.; Zatorski, Raymond A.

2005-07-12

238

Thermal-hydraulic simulation of helium expulsion from a cable-in-conduit conductor  

International Nuclear Information System (INIS)

This paper presents simulation results of a quenching cable-in-conduit conductor (CICC) for application in Superconducting Magnetic Energy Storage (SMES). The details of the model and its computational implementation (the code HEDUMP) are discussed. An extensive verification process shows that HEDUMP can accurately model a quenching CICC. Preliminary results of the simulation are given and discussed. In particular, the normal zone propagation is studied. It is shown that CICCs exhibit a thermohydraulic quench back behavior whereby superconducting regions ahead of the normal front are suddenly driven normal by frictional dissipation and/or compression heating of the fluid

239

Thermal-hydraulic simulation of helium expulsion from a cable-in-conduit conductor  

Energy Technology Data Exchange (ETDEWEB)

This paper presents simulation results of a quenching cable-in-conduit conductor (CICC) for application in Superconducting Magnetic Energy Storage (SMES). The details of the model and its computational implementation (the code HEDUMP) are discussed. An extensive verification process shows that HEDUMP can accurately model a quenching CICC. Preliminary results of the simulation are given and discussed. In particular, the normal zone propagation is studied. It is shown that CICCs exhibit a thermohydraulic quench back behavior whereby superconducting regions ahead of the normal front are suddenly driven normal by frictional dissipation and/or compression heating of the fluid.

Luongo, C.A.; Loyd, R.J.; Chen, F.K.; Peck, S.D.

1989-03-01

240

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

Science.gov (United States)

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

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

2006-12-01

241

Oesophageal Conduit – a Cause of Diffuse Mediastinal Uptake on Thyroid Scintigraphy  

Science.gov (United States)

99mTc-pertechnetate scintigraphy plays an essential role in the management of a variety of thyroid and parathyroid disorders. The authors report an unusual case of mediastinal tracer distribution of 99mTc-pertechnetate and 99mTc-MIBI in relation to an oesophageal conduit following oesophago-gastrectomy and reconstructive surgery on thyroid scintigraphy. This is a rare but important cause of diffuse mediastinal uptake on thyroid scintigraphy. An awareness of abnormal anatomy as well as altered physiological tracer uptake would help to avoid any diagnostic pitfall. Conflict of interest:None declared. PMID:24416630

Sonoda, Luke I.; Balan, Kottekkattu K.

2013-01-01

242

Shock Wave Formation in the Collapse of a Vapor Nanobubble  

Science.gov (United States)

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

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

2015-02-01

243

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

244

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

245

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

International Nuclear Information System (INIS)

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

246

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

Science.gov (United States)

Applications based on the movement of domain walls (DWs) in magnetic nanowires (NWs) require a good DW conduit behavior, i.e. a significant difference between DW nucleation and propagation fields. In this work, we have systematically studied how this property evolves in cobalt NWs grown by focused electron beam induced deposition (FEBID) as a function of global gallium irradiation, for irradiation doses up to 1.24 × 10(17) ions cm(-2). Whereas for high doses the DW conduit is lost, below 6.42 × 10(15) ions cm(-2) the difference between the two fields increases with irradiation, becoming up to ?9 times larger than for non-irradiated wires, due to a strong increase in the nucleation field, while the propagation field remains approximately constant. This behavior stems from two effects. The first effect is a decrease in the magnetic volume of the parasitic halo around the NW, typically present in FEBID nanostructures, leading to the disappearance of weak nucleation centers. The second effect is the formation of a 20 nm outer shell with Co crystals about twice the size of those forming the NW core, causing a net increase of the local magnetocrystalline anisotropy. The results presented here are important for the potential use of magnetic NWs grown by FEBID in DW-based devices, and might also be of interest for magnetic NWs fabricated by other techniques. PMID:23899474

Serrano-Ramón, L; Fernández-Pacheco, A; Córdoba, R; Magén, C; Rodríguez, L A; Petit, D; Cowburn, R P; Ibarra, M R; De Teresa, J M

2013-08-30

247

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

Science.gov (United States)

Biocompatible synthetic polymers are largely used in the bio-medical domain, tissue engineering and in controlled release of medicines. Polymers can be used in the achievement of cardiac and vascular devices, mammary implants, eye lenses, surgical threads, nervous conduits, adhesives, blood substitutes, etc. Our study was axed on the development of cytotoxicity tests for 3 synthetic polymers, namely polyvinyl alcohol, polyethylene glycol and polyvinyl chloride. These tests targeted to determine the viability and morphology of cells (fibroblasts) that were in indirect contact with the studied polymers. Cell viability achieved for all the studied synthetic polymers allowed their frame in biocompatible material category. Cell morphology did not significantly change, thus accomplishing a new biocompatibility criterion. The degree of biocompatibility of the studied polymers varied. Polyvinyl alcohol presented the highest grade of biocompatibility and polyvinyl chloride placed itself at the lowest limit of biocompatibility. The results achieved allowed the selection of those polymers that (by enhancing their degrees of biocompatibility due to the association with various biopolymers) will be used in the development of new biocompatible materials, useful in nervous conduits manufacture. PMID:22567047

Mihai, R; Florescu, I P; Coroiu, V; Oancea, A; Lungu, M

2011-08-15

248

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

249

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

Scientific Electronic Library Online (English)

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

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

1988-08-01

250

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

251

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

252

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

253

Soil clean up by in-situ aeration. X. Vapor stripping of mixtures of volatile organics obeying Raoult's law  

International Nuclear Information System (INIS)

Mathematical models are developed for the soil vapor extraction of nonaqueous phase liquid mixtures obeying Raoult's law. The models make the local equilibrium assumption for vapor and liquid, and can handle up to three components. Vapor stripping in laboratory columns, by means of a single vertical well screened at the bottom (axial symmetry) and by means of a single horizontal slotted pipe (Cartesian symmetry), are modeled. The models run on IBM PC-AT compatible microcomputers. Some representative results are given

254

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

255

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

International Nuclear Information System (INIS)

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

256

Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms  

Science.gov (United States)

In Strelec Quarry, the Czech Republic, an underground conduit network > 300 m long with a volume of ~ 104 m3 and a catchment of 7 km2 developed over 5 years by groundwater flow in Cretaceous marine quartz sandstone. Similar landforms at natural exposures (conduits, slot canyons, undercuts) are stabilized by case hardening and have stopped evolving. The quarry offers a unique opportunity to study conduit evolution in sandstone at local to regional scales, from the initial stage to maturity, and to characterize the erosion processes which may form natural landforms prior to stabilization. A new technique was developed to distinguish erodible and non-erodible sandstone surfaces. Based on measurements of relative erodibility, drilling resistance, ambient and water-saturated tensile strength (TS) at natural and quarry exposures three distinct kinds of surfaces were found. 1) Erodible sandstone exposed at ~ 60% of surfaces in quarry. This sandstone loses as much as 99% of TS when saturated. 2) Sub-vertical fracture surfaces that are non-erodible already prior to exposure at ground surface and which keep considerable TS if saturated. 3) Case hardened surfaces that start to form after exposure. In favorable conditions they became non-erodible and reach the full TS in just 6 years. An increase in the hydraulic gradient from ~ 0.005 to > 0.02 triggered conduit evolution, based on long-term monitoring of water table in 18 wells and inflows to the quarry. Rapidly evolving major conduits are characterized by a channel gradient of ~ 0.01, a flow velocity ~ 40 cm/s and sediment concentration ~ 10 g/l. Flow in openings with a discharge 1 ml/s and hydraulic gradient > 0.05 exceeds the erosion threshold and initiates piping. In the first phase of conduit evolution, fast concentrated flow mobilizes erodible sandstone between sets of parallel fractures in the shallow phreatic zone. In the second phase the conduit opening mainly expands vertically upward into the vadose zone by mass wasting of undercut sandstone slabs. Mass wasting is responsible for > 90% of mobilized sandstone. Sides of the mature conduits are protected by non-erodible fracture surfaces. Natural landforms were probably formed very rapidly by overland flow, piping and possibly fluidization during or at the end of the glacial periods when sandstone was not yet protected by case hardening.

Bruthans, Jiri; Svetlik, Daniel; Soukup, Jan; Schweigstillova, Jana; Valek, Jan; Sedlackova, Marketa; Mayo, Alan L.

2012-12-01

257

MIR Measurements of Atmospheric Water Vapor Profiles  

Science.gov (United States)

Three subjects related to atmospheric water vapor profiling using the 183.3 GHz absorption line are discussed in this paper. First, data acquired by an airborne millimeter-wave imaging radiometer (MIR) over ocean surface in the western Pacific are used to estimate three-dimensional (3-D) distribution of atmospheric water vapor. The instrument's radiometric measurements with mixed vertical and horizontal polarizations require modifications to the retrieval algorithm used in the past. It is demonstrated that, after the modifications, the new algorithm can provide adequate retrieval of water vapor profiles, even though the measured data are of mixed polarizations. Next, the retrieved profiles, in terms of water vapor mixing ratio rho (g/kg), are compared with those measured in near concurrence by dropsondes from a research aircraft in the western Pacific and by a ground-based Raman lidar at Wallops Island, Virginia. The ratio of the standard deviation to the mean rho is found to be 0.12 at 0.25 km altitude and gradually degraded to 0.67 at the highest altitude of the retrieval of 10.25 km. Finally, the effect of the "initial guess" relative humidity profile on the final retrieved product is analyzed with respect to the condition for the convergent retrieval. It is found that the effect is minimal if the initial profile is not unrealistically different from the true one. If the initial profile is very different from the true one, the final retrieved product could be subject to a substantial error. Tightening of the convergent condition in the retrieval helped reduce magnitude of the error, but not remove it totally. It is concluded that an initial profile based on climatology is likely to provide most reliable retrieval results.

Wang, J. R.; Racette, P.; Chang, L. A.

1997-01-01

258

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.

259

Analysis of the global ISCCP TOVS water vapor climatology  

Science.gov (United States)

A climatological examination of the global water vapor field based on a multiyear period of successfull satellite-based observations is presented. Results from the multiyear global ISCCP TIROS Operational Vertical Sounder (TOVS) water vapor dataset as operationally produced by NESDIS and ISCCP are shown. The methods employed for the retrieval of precipitable water content (PWC) utilize infrared measurements collected by the TOVS instrument package flown aboard the NOAA series of operational polar-orbiting satellites. Strengths of this dataset include the nearly global daily coverage, availability for a multiyear period, operational internal quality checks, and its description of important features in the mean state of the atmosphere. Weaknesses of this PWC dataset include that the infrared sensors are unable to collect data in cloudy regions, the retrievals are strongly biased toward a land-based radiosonde first-guess dataset, and the description of high spatial and temporal variability is inadequate. Primary consequences of these factors are seen in the underestimation of ITCZ water vapor maxima, and underestimation of midlatitude water vapor mean and standard deviation values where transient atmospheric phenomena contribute significantly toward time means. A comparison of TOVS analyses to SSM/I data over ocean for the month of July 1988 shows fair agreement in the magnitude and distribution of the monthly mean values, but the TOVS fields exhibit much less temporal and spatial variability on a daily basis in comparison to the SSM/I analyses. The emphasis of this paper is on the presentation and documentation of an early satellite-based water vapor climatology, and description of factors that prevent a more accurate representation of the global water vapor field.

Wittmeyer, Ian L.; Vonder Haar, Thomas H.

1994-01-01

260

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

261

Pressure drop measurements on supercritical helium cooled cable in conduit conductors  

International Nuclear Information System (INIS)

Forced flow cable-in-conduit conductors with large cooled surface areas provide excellent stability margins at the price of high frictional losses and large pumping power requirements. For extensive projects such as the International Thermonuclear Experimental Reactor design cooperation it is essential to know the pressure drops to be expected from different conductor geometries and operating conditions. To measure these pressure drops a flow loop was constructed to circulate supercritical helium through different conductors. The loop is surrounded by a 5 K radiation shield to allow for stable operation at the required temperatures. A coil heat exchanger immersed in a helium bath is used to remove the heat generated by the pump. Pressure drops are measured across 1 meter lengths of the conductors for various mass flow rates. Friction factor versus Reynolds number plots are used to correlate the data

262

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

263

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

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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

264

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

International Nuclear Information System (INIS)

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

265

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

266

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

267

Voltage-gated pinning in a magnetic domain-wall conduit  

Science.gov (United States)

In spintronic devices relying on magnetic domain-wall (DW) motion, robust control over the DW position is required. We use electric-field control of perpendicular magnetic anisotropy to create a voltage-gated pinning site in a microstructured Pt/Co/AlOx DW conduit. A DW pins at the edge of a gate electrode, and the strength of pinning can be tuned linearly and reversibly with an efficiency of 0.22(1) mT/V. This result is supported by a micromagnetic model, taking full account of the anisotropy step at the gate edge, which is directly caused by a change in the electron density due to the choice of material.

Franken, J. H.; Yin, Y.; Schellekens, A. J.; van den Brink, A.; Swagten, H. J. M.; Koopmans, B.

2013-09-01

268

Total cavopulmonary connection with innovative combined lateral tunnel and extracardiac conduit in heterotaxy syndrome.  

Science.gov (United States)

Total cavopulmonary connection remains a challenging procedure when treating heterotaxy syndrome patients with a widely separate drainage of the inferior vena cava and the hepatic vein into the common atrium. We trimmed a Gore-Tex tube graft (W.L. Gore & Associates, Flagstaff, AZ) to form a skirt to cover both openings of the inferior vena cava and the hepatic vein. This tubular structure pierces the atrium and travels outside the heart, and then reaches the inferior side of the pulmonary artery to avoid pulmonary vein obstruction. We then sutured the pierced atriotomy margin to the conduit. This innovative procedure has been shown to accommodate the widely separated hepatic vein drainage with a promising outcome. PMID:22051298

Hsu, Kang-Hong; Chang, Chung-I

2011-11-01

269

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

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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

270

Heterogeneity of endothelial cell phenotype within and amongst conduit vessels of the swine vasculature.  

Science.gov (United States)

The purpose of this study was to investigate the extent of endothelial cell phenotypic heterogeneity throughout the swine vasculature, with a focus on the conduit vessels of the arterial and venous circulations. We tested the hypothesis that atheroprone arteries exhibit higher expression of markers of inflammation and oxidative stress than do veins and atheroresistant arteries. The study sample included tissues from 79 castrated, male swine. Immediately after the animals were killed, endothelial cells were mechanically scraped from isolated segments of the thoracic and abdominal aorta, carotid, brachial, femoral and renal arteries, and the vein regionally associated with each of these vessels, as well as the internal mammary and right coronary arteries. Cells were also taken from two regions of the aortic arch contrasted by atheroprone versus atherosusceptible haemodynamics. Endothelial cell phenotype was assessed by either immunoblotting or quantitative real-time PCR for a host of both pro- and anti-atherogenic markers (e.g. endothelial nitric oxide synthase, p67phox, cyclo-oxygenase-1 and superoxide dismutase 1). Marked heterogeneity across the vasculature was observed in the expression of both pro- and anti-atherogenic markers, at both the protein and transcriptional levels. In particular, the coronary vascular endothelium expressed higher levels of the oxidative stress marker p67phox (P veins. We show, for the first time, that endothelial cell phenotype is variable within vessels, across six major vascular territories, and between the arterial and venous circulations. Importantly, even straight vessel segments from systemic conduit arteries (e.g. brachial and carotid arteries) exhibited regional phenotypic heterogeneity; a finding not expected on the basis of local haemodynamic forces alone. PMID:22542613

Simmons, Grant H; Padilla, Jaume; Laughlin, M Harold

2012-09-01

271

Conduit controlled burial dolomitization in Devonian reservoirs of western Canada sedimentary basin  

Energy Technology Data Exchange (ETDEWEB)

More than half of the carbonate buildups consist of secondary dolomites, whereas adjacent ones are only slightly dolomitized. Examples occur at seven different stratigraphic levels: Keg River, Pine Point, Slave Point, Swan Hills, Leduc, Nisku, and Wabamun (ranging from Givetian to late Famennian). The diagenesis, especially the dolomitization, is poorly known. These secondary dolomites are syn- to post-stylolitization and probably formed at intermediate burial depths below about 700 to 1000 m. Most are not related to unconformities or evaporites and were not subjected to freshwater diagenesis or refluxing fluids from an evaporite basin. These dolomites are medium to coarse crystalline, sucrosic, or saddle types. Porosities remain similar to the precursor limestones (6 to 10%) whereas permeabilities generally increased, depending on the type of dolomite. Enormous amounts of fluids are required during dolomitization. Three main factors appear to govern the occurrence of these secondary dolomites: (1) platform margins or buildups adjacent to shale basins; (2) underlying permeable carbonate platforms; and (3) fracture and fault systems. The best examples of platforms and buildups associated with basin shales are the Slave Point platform in British Columbia and the Miette buildup in the Rocky Mountains. Beneath some Leduc buildups a permeable platform (Cooking Lake) probably acted as a conduit for transporting dolomitizing fluids and later hydrocarbons updip. They are only dolomitized where the underlying platform is also dolomitized. Some buildups are related to fracture and fault systems (trending north-northeast, northeast, and northwest) that appear to have formed vertical conduits in conjunction with porous and permeable units. The best examples are Pine Point, Nisku (West Pembina), and Wabamun (Normanville).

Mountjoy, E.

1987-05-01

272

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

273

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

274

Welding of Pyroclastic Conduit Infill: A Mechanism for Cyclical Explosive Eruptions  

Science.gov (United States)

Vulcanian style eruptions are small to moderate sized singular to cyclical events commonly having volcanic explosivity indices (VEI) of 1-3. They produce pyroclastic flows, disperse tephra over considerable areas and can occur as precursors to larger (e.g. Plinian) eruptions. Here we present a study on the evolution of the physical properties (strain, porosity, permeability and ultrasonic wave velocities) of breadcrust bombs recovered from the deposits of the 2350 B.P. eruption of Mt Meager, BC, Canada. These accessory lithics are fragments of welded intra vent deposits formed during compaction and deformation processes operating in the shallow (less than 2 km) conduit. The deformation experienced by these samples is a combination of compaction within the conduit and post-compaction stretching associated with the subsequent eruption. 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. However, permeability varies little along the elongation direction of the fabric. Similarly, ultrasonic wave velocities increase along the compaction direction and remain unaffected along the direction of fabric stretching; Poisons ratio increases along the fabric stretching direction. We combine these physical property measurements with models describing the timescales of porosity loss and to explore the timescales of permeability reduction and re-pressurization of the edifice. Modelling results and reconstruction of the deformation history also suggest the potential for a low-cost technique for monitoring the pressure build-up within volcanic systems based on fumarolic activity.

Kolzenburg, Stephan; Russell, James K.

2014-05-01

275

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

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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

276

Endothelial barrier dysfunction in diabetic conduit arteries: a novel method to quantify filtration.  

Science.gov (United States)

The endothelial barrier plays an important role in atherosclerosis, hyperglycemia, and hypercholesterolemia. In the present study, an accurate, reproducible, and user-friendly method was used to further understand endothelial barrier function of conduit arteries. An isovolumic method was used to measure the hydraulic conductivity (L(p)) of the intact vessel wall and medial-adventitial layer. Normal arterial segments with diameters from 0.2 to 5.5 mm were used to validate the method, and femoral arteries of diabetic rats were studied as an example of pathological specimens. Various arterial segments confirmed that the volume flux of water per unit surface area was linearly related to intraluminal pressure, as confirmed in microvessels. L(p) of the intact wall varied from 3.5 to 22.1 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 7-180 mmHg. Over the same pressure range, L(p) of the endothelial barrier changed from 4.4 to 25.1 × 10(-7) cm·s(-1)·cmH(2)O(-1). During perfusion with albumin-free solution, L(p) of rat femoral arteries increased from 6.1 to 13.2 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 10-180 mmHg. Hyperglycemia increased L(p) of the femoral artery in diabetic rats from 2.9 to 5.5 × 10(-7) cm·s(-1)·cmH(2)O(-1) over the pressure range of 20-135 mmHg. In conclusion, the L(p) of a conduit artery can be accurately and reproducibly measured using a novel isovolumic method, which in diabetic rats is hyperpermeable. This is likely due to disruption of the endothelial glycocalyx. PMID:23220330

Lu, Xiao; Huxley, Virginia H; Kassab, Ghassan S

2013-02-01

277

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

278

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

Science.gov (United States)

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

Coombs, C. R.; Hawke, B. R.; Wilson, L.

1990-01-01

279

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.

280

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

International Nuclear Information System (INIS)

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

281

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

Science.gov (United States)

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

Peterson, Eric W.; Wicks, Carol M.

2006-09-01

282

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

283

Creation of gastric conduit free-graft with intraoperative perfusion imaging during pancreaticoduodenectomy in a patient post esophagectomy  

Directory of Open Access Journals (Sweden)

She underwent open pancreaticoduodenectomy, and to maintain perfusion to the gastric conduit a microvascular anastomosis of the gastroepiploic pedicle was performed to the middle colic vessels. Intraoperative fluorescent imaging was used to evaluate the anastomosis as well as gastric and duodenal perfusion during the case.

Spyridon Pagkratis

2015-01-01

284

Scale considerations and vapor explosions  

International Nuclear Information System (INIS)

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

285

Rare earth vapor laser studies  

International Nuclear Information System (INIS)

The fluorescence decay rates of vapor phase neodymium aluminum chloride complex (Nd-Al-Cl) and neodymium-thd-chelate have been measured as functions of temperature, partial pressure and optical excitation intensity. Fluorescence quenching due to both ground and excited state collisions was observed in Nd-Al-Cl vapor. In constrast, quenching in the Nd-thd vapor was found to be dominated by multiquantum excitation of molecular vibrations. The fluorescence kinetics of Tb-Al-Cl vapor have also been examined under conditions of intense excitation of terbium 5d levels by a KrF laser source. Both prompt and delayed fluorescence of the 4f8(5D4) metastable level were observed together with evidence of excited-state collisional quenching. In laser amplifier experiments, a transient (greater than or equal to 10 ?sec) population inversion was produced in Nd-Al-Cl vapor with a small signal gain coefficient greater than or equal to 0.25%/cm and a stored energy density approximately equal to 35 J/liter. Available data for the rare earth vapors are related to scaling requirements of large amplifiers for laser fusion application

286

Impact Vaporization of Planetesimal Cores  

Science.gov (United States)

The degree of mixing and chemical equilibration between the iron cores of planetesimals and the mantle of the growing Earth has important consequences for understanding the end stages of Earth's formation and planet formation in general. At the Sandia Z machine, we developed a new shock-and-release technique to determine the density on the liquid-vapor dome of iron, the entropy on the iron shock Hugoniot, and the criteria for shock-induced vaporization of iron. We find that the critical shock pressure to vaporize iron is 507(+65,-85) GPa and show that decompression from a 15 km/s impact will initiate vaporization of iron cores, which is a velocity that is readily achieved at the end stages of planet formation. Vaporization of the iron cores increases dispersal of planetesimal cores, enables more complete chemical equilibration of the planetesimal cores with Earth's mantle, and reduces the highly siderophile element abundance on the Moon relative to Earth due to the expanding iron vapor exceeding the Moon's escape velocity. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000.

Kraus, R. G.; Root, S.; Lemke, R. W.; Stewart, S. T.; Jacobsen, S. B.; Mattsson, T. R.

2013-12-01

287

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

288

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

289

Melt and vapor characteristics in an electron beam evaporator  

Energy Technology Data Exchange (ETDEWEB)

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.

Blumenfeld, L.; Fleche, J.L.; Gonella, C.; Soubbaramayer

1994-12-31

290

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

291

Effects of gas exsolution and microlite crystallization on the complexity of conduit flow dynamics during lava dome eruptions  

Science.gov (United States)

During lava dome eruptions, gas exsolution and microlite crystallization strongly affect the dynamics of conduit flow. Generally, the dynamics of viscous pipe flow can be characterized by the relationship between source pressure and mass flow rate; here, the ratio of source pressure to mass flow rate is defined as effective resistance, which normally has a positive value for stable pipe flows. For conduit flow involving gas exsolution and crystallization, however, it can have negative values, which causes complex dynamics such as abrupt initiation and/or termination of an eruption as well as cyclic change of magma discharge rate. There are at least two possible mechanisms that result in such a negative effective resistance. First, delay of crystallization induces a decrease in effective viscosity of liquid-crystal mixture with increasing mass flow rate. Second, if average gas volume fraction in the conduit increases with mass flow rate, the resistance of flow due to gravitational load decreases with increasing mass flow rate. In this study we investigated how the relative importance of these two mechanisms depends on petrological properties of magma on the basis of a one-dimensional steady conduit flow model. The results of our numerical analyses are summarized as follows. Effective viscosity of liquid-crystal mixture drastically increases as total volume fraction of crystals exceeds a critical value (about 0.6). The effective viscosity sensitively varies with mass flow rate under conditions where the range of variation in crystal content due to delay of microlite crystallization overlaps this critical value. On the other hand, the gas volume fraction in the conduit is governed by the balance between upward gas drag force and downward forces due to gravitational load and viscous wall friction. As mass flow rate decreases, the gas drag force decreases, which allows an efficient gas escape from the dense liquid magma; therefore, gas volume fraction in the conduit decreases with decreasing mass flow rate, and vice versa. As magma viscosity increases, the ascent of the liquid magma is suppressed because of high wall friction, whereas the gas ascends easily; as a result, gas volume fraction in the conduit is kept low regardless of mass flow rate. These results imply that the primary mechanism leading to the negative effective resistance depends on phenocryst content of magmas. When phenocryst content is greater than 0.5, viscous wall friction is large enough to suppress the increase in gas volume fraction in the conduit regardless of mass flow rate. In this case, the delay of microlite crystallization is the main factor that induces the negative effective resistance. For lower phenocryst contents, on the other hand, gas volume fraction in the conduit significantly varies with mass flow rate, whereas the decrease in effective viscosity due to delay of crystallization becomes less important. In this case, the decrease in gravitational load due to gas expansion is the main factor that induces the negative effective resistance.

Koyaguchi, T.; Kozono, T.

2010-12-01

292

Water Vapor Imagery: Water Vapor and Jet Streams  

Science.gov (United States)

This is a self-paced, on-line tutorial where learners can identify and analyze jet streams using water vapor imagery from weather satellites. Learners are introduced to the concept and function of the water vapor channel and how these images compare with weather models. An optional embedded refresher tutorial with providing meteorological background information about jet streams supports student-centered investigations in three learning scenarios: a jet stream tracking challenge made by a TV meteorologist, analyzing data in a in-air turbulence scenario involving an airline pilot, and a decision-making challenge involving the launching and tracking of a weather balloon. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the third of three modules in the tutorial, Water Vapor Imagery. (Note: requires Java plug-in)

293

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

International Nuclear Information System (INIS)

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

294

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

295

Focusing Light Beams To Improve Atomic-Vapor Optical Buffers  

Science.gov (United States)

Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

2010-01-01

296

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

Science.gov (United States)

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

Kuchma, Anatoly; Markov, Maxim; Shchekin, Alexander

2014-05-01

297

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

International Nuclear Information System (INIS)

We utilized a vapor-liquid-solid growth technique to synthesize indium oxide, gallium oxide, and tin oxide nanowires using chemical vapor transport with gold nanoparticles as the catalyst. Using identical growth parameters, we were able to synthesize single crystal nanowires typically 40-100 nm diameter and more than 10-100 m long. The products were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). All the wires were grown under the same growth conditions with growth rates inversely proportional to the source metal vapor pressure. Initial experiments show that different transparent oxide nanowires can be grown simultaneously on a single substrate with potential application for multicomponent gas sensors

298

Conduit-margin faulting at Mount St. Helens - a seismogenic process?  

Science.gov (United States)

The 2004-2008 eruption of Mount St. Helens produced dacite spines mantled by fault gouge and breccia, with textures and structures remarkably similar to those in brittle tectonic fault zones. The spines are mantled by 1-3 meters of cataclastic fault rocks, comprising a fault core overlying a damage zone. The outermost surface of the fault core consists of 1-3-mm-thick layers of extremely fine-grained slickenside-bearing ultracataclasite, within finely comminuted fault gouge and soft cataclasite. The fault core varies in thickness from spine to spine, ranging from a few centimeters to about 1 m. Interior to the gouge is a 1-3-m-thick damage zone composed of dense cataclastic breccia, which overlies massive dacite lava of the spine interior. Structures and micro-textures indicate entirely brittle deformation, including rock breakage, shearing, grain flow, faulting and gas escape through intergranular porosity and along fractures. Slickenside lineations on fault surfaces and consistent orientations of thousands of Riedel shears in the damage zone indicate shear between the vertically extruding spines and the formerly adjacent conduit wall. Field relations indicate that Riedel shears formed in a continuous cycle of deformation, beginning with episodes of fracture and granular flow and followed by transfer of slip to bounding fault planes. Granular flow in the cataclasite may also result in stress concentration along force-chains as seen in laboratory experiments. Paleomagnetic pole positions, demagnetization paths, and oxide mineralogy indicate that cataclasis took place within the solidified and oxidizing sub-vertical volcanic conduit and at temperatures above 500°C. Low water content of matrix glass is consistent with brittle behavior at these high temperatures, and along with tridymite in the groundmass of the dacite, requires nearly complete decompression-driven solidification at depths slickenside surfaces of principal shears within the gouge suggest stick-slip motion, which may have produced the hybrid earthquakes. Additionally, grain-flow textures in the spine boundary gouge suggest that periods of nearly aseismic extrusion were accommodated by grain flow.

Pallister, J. S.; Cashman, K. V.; Hagstrum, J. T.

2008-12-01

299

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)

300

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-01

301

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

International Nuclear Information System (INIS)

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

302

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

OpenAIRE

The Thirty Meter Telescope (TMT) and the European Extremely Large Telescope (E-ELT) site testing teams have recently finalized their site testing studies. Since atmospheric water vapor is the dominant source of absorption and increased thermal background in the infrared, both projects included precipitable water vapor (PWV) measurements in their corresponding site testing campaigns. TMT planned to monitor PWV at the sites of interest by means of using infrared radiometers. T...

Otarola, Angel C.; Querel, Richard; Kerber, Florian

2011-01-01

303

Thermal plasma chemical vapor deposition  

International Nuclear Information System (INIS)

Thermal plasmas, with temperatures up to and even exceeding 104 K, are capable of producing high density vapor phase precursors for the deposition of relatively thick films. Although this technology is still in its infancy, it will fill the void between the relatively slow deposition processes such as physical vapor deposition and the high rate thermal spray deposition processes. In this chapter, the present state-of-the-art of this field is reviewed with emphasis on the various types of reactors proposed for this emerging technology. Only applications which attracted particular attention, namely diamond and high Tc superconducting film deposition, are discussed in greater detail. (orig.)

304

Vapor deposition of thin films  

Science.gov (United States)

A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

1992-01-01

305

The Utopia/Isidis overlap: Possible conduit for mud volcanism on Mars  

Science.gov (United States)

The largest areal concentration of pitted cones on Mars is located in the southwest section of Utopia basin. This particular area of pitted cones has been attributed to mud volcanism; several factors may have facilitated extensive mud volcanism at this location. The concentration of pitted cones is located where Utopia basin intersects Isidis basin; both features are multi-ring impact basins. On Earth, seismic investigations have shown that the outer rings of the Chicxulub multi-ring impact basin extend to the Mohorovi?i? discontinuity (Moho). If this is true on Mars as well, the fractures could act as conduits for water from Utopia Planitia, the site of a large, putative water body. It has been shown that methane can be generated at the mantle on Earth. On Mars this possible source of methane could combine with the infiltrated water to generate clathrates. While methane is not currently being released at the location of the pitted cones it could have been in the past. Three locations of methane release have been observed on Mars, two of which are located on the same outer ring of Isidis basin that intersects the pitted cone population. The area of Utopia basin that contains the large population of pitted cones is adjacent to the highland/lowland boundary where extensive deposition would have occurred. Extensive deposition combined with the potential for methane release may have contributed to the large population of pitted cones in this area of the Utopia basin.

McGowan, Eileen M.

2011-04-01

306

A new cable-in-conduit conductor magnet with insulated strands  

International Nuclear Information System (INIS)

Many studies have used cable-in-conduit conductor (CICC) coils in trying to develop an AC superconducting magnet because of its enormous potential if AC losses were low and insulation voltage was high. The strands in the most recent CICC magnets are coated with chromium or another metal with high electrical resistance to order to induce current re-distribution among the strands and to avoid a quench caused by a current imbalance. Current re-distribution is highly complex and very difficult to analyze because the conditions of the strand surfaces and the contact areas vary greatly with the operation of the conductor. If, however, the cable currents were well-balanced, insulating the strands would be the best way to reduce AC losses. We propose a new CICC magnet structure featuring a current lead that balances the strand currents via its resistance. Having calculated current balances, we find that strand currents are well within the present parameters for nuclear fusion experiments and superconducting magnet energy storages. (author)

307

Effect of voltage current characteristic smoothness on the stability margin of cable-in-conduit conductors  

Science.gov (United States)

Experimental and numerical investigation of the AC losses induced by the transient magnet field (TMF) in cable-in-conduit conductors (CICC) revealed some interesting results. First of all, the critical current in the strands could be exceeded as a result of simultaneous increase of the strand temperature due to AC losses and the addition of the induced shielding currents to the transport current. Secondly, after the sample reaches its critical state the energy stored in the loops formed by the superconducting strands and normal "matrix" quickly dissipates in the normal matrix of the strands and in the normal "matrix" of the bundle. This results in a step increase of the conductor temperature. It was logical to assume that during the process preceding the occurrence of the first flux-jump, the maximum temperature and shielding current could depend on the smoothness of the voltage-current characteristic (VCC) of the superconducting strands. In other words, the smoothness of the VCC of the superconducting strands should influence the stability margin of a conductor. A numerical investigation of the VCC smoothness effect on stability margin was carried out for a wide range of the Stekly parameter, ?, and varying the dimensionless transport current i = It/ Ic (0 ? ? VCC smoothness increases, when the Stekly parameter lies in the range 0 ? ? VCC smoothness increases, when the Stekly parameter ? ? 1.

Lelekhov, S. A.; Naumov, P. G.

2007-03-01

308

Full-scale calculation of the coupling losses in ITER size cable-in-conduit conductors  

International Nuclear Information System (INIS)

With the numerical cable model JackPot it is possible to calculate the interstrand coupling losses, generated by a time-changing background and self-field, between all strands in a cable-in-conduit conductor (CICC). For this, the model uses a system of equations in which the mutual inductances between all strand segments are calculated in advance. The model works well for analysing sub-size CICC sections. However, the exponential relationship between the model size and the computation time make it unpractical to simulate full size ITER CICC sections. For this reason, the multi-level fast multipole method (MLFMM) is implemented to control the computation load. For additional efficiency, it is written in a code that runs on graphics processing units, thereby utilizing an efficient low-cost parallel computation technique. A good accuracy is obtained with a considerably fast computation of the mutually induced voltages between all strands. This allows parametric studies on the coupling loss of long lengths of ITER size CICCs with the purpose of optimizing the cable design and to accurately compute the coupling loss for any applied magnetic field scenario. (paper)

309

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

Science.gov (United States)

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

Raja Sekhar, Dondapati; Rao, V. V.

2013-02-01

310

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

Directory of Open Access Journals (Sweden)

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

Ross C. Elliott

2014-08-01

311

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

Energy Technology Data Exchange (ETDEWEB)

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

Yuhu Zhai, Pierluigi Bruzzone, Ciro Calzolaio

2013-03-19

312

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

Science.gov (United States)

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

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

2006-09-01

313

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

International Nuclear Information System (INIS)

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

314

Numerical simulation of the stability in long cable-in-conduit conductors for fusion magnets  

International Nuclear Information System (INIS)

The stability phenomenon is investigated numerically for a quench initiating in a cable-in-conduit conductor (CICC) at a significant distance from the ends. The thermo-hydraulic computer program, CICC, was used. The geometry chosen for this study is a toroidal field (TF) coil for the conceptual design activity (CDA) of the International Thermonuclear Experimental Reactor (ITER). Previous studies of short conductors have shown that convective helium flows, induced by the initiating heat pulse, control the stability of the conductor. The present study of a long conductor exhibits reduced energy margins and the absence of a transition region between the well-cooled and ill-cooled stability regions because the initiating heat pulse has difficulty sustaining a convective flow. The effect of heat-pulse duration and heated length were considered. For short, high-energy heat pulses, high convective and conductive heat-transfer coefficients can only be mismatched for 10 ms. If the heat-pulse energy is spread your 100 ms, the steady-state heat-transfer coefficient is sufficient to stabilize the conductor. Pulse durations between 10 and 100 ms cause a decrease in energy margin. On the other hand, the conductor length heated was found to have only a small effect on stability. 3 refs

315

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

Science.gov (United States)

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

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

2014-06-01

316

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

LENUS (Irish Health Repository)

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

Halpenny, M

2012-02-03

317

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

Scientific Electronic Library Online (English)

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

Ross C., Elliott.

2014-01-01

318

Evaluation of Small Intestine Submucosa and Poly(caprolactone-co-lactide) Conduits for Peripheral Nerve Regeneration.  

Science.gov (United States)

The present study employed nerve guidance conduits (NGCs) only, which were made of small intestine submucosa (SIS) and poly(caprolactone-co-lactide) (PCLA) to promote nerve regeneration in a peripheral nerve injury (PNI) model with nerve defects of 15?mm. The SIS- and PCLA-NGCs were easily prepared by rolling of a SIS sheet and a bioplotter using PCLA, respectively. The prepared SIS- and PCLA-NGCs fulfilled the general requirement for use as artificial peripheral NGCs such as easy fabrication, reproducibility for mass production, suturability, sterilizability, wettability, and proper mechanical properties to resist collapsing when applied to in vivo implantation. The SIS- and PCLA-NGCs appeared to be well integrated into the host sciatic nerve without causing dislocations and serious inflammation. All NGCs stably maintained their NGC shape for 8 weeks without collapsing, which matched well with the nerve regeneration rate. Staining of the NGCs in the longitudinal direction showed that the regenerated nerves grew successfully from the SIS- and PCLA-NGCs through the sciatic nerve-injured gap and connected from the proximal to distal direction along the NGC axis. SIS-NGCs exhibited a higher nerve regeneration rate than PCLA-NGCs. Collectively, our results indicate that SIS- and PCLA-NGCs induced nerve regeneration in a PNI model, a finding that has significant implications in the future with regard to the feasibility of clinical nerve regeneration with SIS- and PCLA-NGCs prepared through an easy fabrication method using promising biomaterials. PMID:25435200

Shim, Sun Woo; Kwon, Doo Yeon; Lee, Bit Na; Kwon, Jin Seon; Park, Ji Hoon; Lee, Jun Hee; Kim, Jae Ho; Lee, Il Woo; Shin, Jung-Woog; Lee, Hai Bang; Kim, Wan-Doo; Kim, Moon Suk

2015-03-01

319

Fracture mechanics analysis including the butt joint geometry for the superconducting conductor conduit of the National Centralized Tokamak  

International Nuclear Information System (INIS)

This paper presents the dependence of the stress intensity factor on a geometrical factor estimated by fracture mechanics analysis around the defect in the butt joint weld of a cable-in-conduit conductor (CICC) of a superconducting coil. The stress intensity factor can be estimated by the Newman-Raju equation applied to the CICC section, but the effect of the difference between the geometry assumed in the equation and the actual CICC geometry has not been clarified yet. Therefore, the three-dimensional finite element method (3D-FEM) is performed to estimate the geometrical factor. As a result, the Newman-Raju equation is considered to be applicable for the assessment of the fracture toughness of the rectangular-shaped conduit because the maximum stress intensity factor by 3D-FEM is only 3% larger than that determined by the Newman-Raju equation for the maximum postulated defect

320

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

International Nuclear Information System (INIS)

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

321

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

322

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

OpenAIRE

The blood and lymphatic vasculatures are structurally and functionally coupled in controlling tissue perfusion, extracellular interstitial fluids, and immune surveillance. Little is known, however, about the molecular mechanisms that underlie the regulation of bloodlymphatic vessel connections and lymphatic perfusion. Here we show in the adult zebrafish and glass catfish (Kryptopterus bicirrhis) that blood-lymphatic conduits directly connect arterial vessels to the lymphatic system. Under hyp...

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

2009-01-01

323

Water content of 1997 vulcanian pumices at Soufriere Hills Volcano (Montserrat) and implications on pre-eruptive conduit conditions  

OpenAIRE

A series of 88 Vulcanian explosions occurred at Soufriere Hills Volcano (Montserrat) between August and October 1997. Conduit conditions prior to each explosion have been explored by analysing representative textures of the eruptive products. We used quantitative analysis of water content in residual glasses (matrix glass) in order to constrain the sampling depth of these ejecta. Studied textures cover the natural range of Vulcanian products and include homogeneous fallout pumices, glassy blo...

Poussineau, Ste?phane; Arbaret, Laurent; Burgisser, Alain

2007-01-01

324

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

OpenAIRE

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 d...

-m, Fitremann J.

2006-01-01

325

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

Science.gov (United States)

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

Paylor, R.

2011-12-01

326

Reconnaissance d'objets multiclasses pour des applications d'aide à la conduite et de vidéo surveillance  

OpenAIRE

La détection de piétons et la reconnaissance des panneaux routiers sont des fonctions importantes des systèmes d'aide à la conduite (anglais : Advanced Driver Assistance System - ADAS). Une nouvelle approche pour la reconnaissance des panneaux et deux méthodes d'élimination de fausses alarmes dans des applications de détection de piétons sont présentées dans cette thèse. Notre approche de reconnaissance de panneaux consiste en trois phases: une segmentation de couleurs, une détect...

Zaklouta, Fatin

2011-01-01

327

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

International Nuclear Information System (INIS)

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

328

Efektivitas Membran Amnion Liofilisasi (Handmade Tubular sebagai Nerve Conduit pada Perbaikan Cedera Saraf Perifer Tikus dengan Gap 5 mm  

Directory of Open Access Journals (Sweden)

Full Text Available Peripheral nerve injury with 5–30 mm gap which is caused by direct injury cases (87% or iatrogenic (12% become a special concern because it could cause a serious disability in the future. Therefore, we need many kinds of nerve repair methods without adding morbidity to the patient. One of the methods is entubulation method, by using natural or synthetic material. This was an animal experimental research by using simple random design in Departement Pharmachology Laboratory, Faculty of Medicine, Universitas Padjadjaran Bandung in May 2012. The samples were used 14 Wistar rats, divided into 2 groups. After creating gap on sciatic nerve, nerve conduit was installed on case group by using handmade tubular lyophilized amnion membrane. Nerve conduit was not installed in control group. After 21 days observation, conduction test and histopathology examination were done. Data were analyzed by using non-parametric statistical analysis sign test. All animals survived without any serious surgical complication. Result showed a significant difference between groups; the conduction test=0.016 (p<0.05, nerve growth to distal gap=0.063 (p<0.05, no radier direction of nerve growth=0.031 (p<0.05. Reaction of inflammation was minimum and there was no difference between two groups. In conclusion, handmade tubular lyophilized amnion membrane is effective as nerve conduit in repair of peripheral nerve injury with 5 mm gap.

R. Dadan G. Gandadikusumah

2013-09-01

329

Extreme frictional processes in the volcanic conduit of Mount St. Helens (USA) during the 2004-2008 eruption  

Science.gov (United States)

The 2004-2008 eruption of Mount St. Helens saw the extrusion of seven high-viscosity spines and formation of discrete shear zones along the conduit margin. At spine 7 this shear zone consists of four structurally distinct layers: the outer surface gouge (L1) crosscuts; a dark, banded layer (L2) which grades into; a moderately sheared layer (L3) and; undeformed rock (L4) inside the spine. Field observations, porosity measurements, geochemistry, mineralogy, microstructure, crystal size- and shape-distribution, kinetic properties and magnetic analyses chart the evolution of deformation processes and products throughout the eruption. Gouge formation was concomitant with characteristic microseismic "drumbeats" at depths 0.5-1 km. In addition, the seismic record shows two larger earthquakes with similar seismic signatures in August 2006, which we conclude represent larger slip amounts along the conduit margin of spine 7. Extensive slip resulted in frictional heating on the order of several hundreds of degrees, melting the highly-viscous, crystalline, ascending magma plug and forming a pseudotachylyte. High ambient temperatures in the conduit resulted in near-equilibrium melting and slow recrystallisation, thus impeding the development of signature pseudotachylyte characteristics and hindering identification. Thus, frictional melting and recrystallisation in ascending magma plugs may be a common, but unidentified, phenomena at composite volcanoes worldwide.

Kendrick, Jackie E.; Lavallée, Yan; Ferk, Annika; Perugini, Diego; Leonhardt, Roman; Dingwell, Donald B.

2012-05-01

330

Specificity of motor axon regeneration: a comparison of recovery following biodegradable conduit small gap tubulization and epineurial neurorrhaphy.  

Science.gov (United States)

Functional recovery is often unsatisfactory after lesions in the peripheral nervous system despite the strong potential for regeneration and advances in microsurgical techniques. Axonal regeneration in mixed nerve into inappropriate pathways is a major contributing factor to this failure. In this study, the rat femoral nerve model of transection and surgical repair was used to evaluate the specificity of motor axon regeneration as well as functional and morphological recovery using biodegradable conduit small gap tubulization compared to epineurial neurorrhaphy. 12 weeks after nerve repair, the specificity was assessed using the retrograde neurotracers TB and DiI to backlabel motor neurons that regenerate axons into muscle and cutaneous pathways. To evaluate the functional recovery of the quadriceps muscle, the quadriceps muscle forces were examined. The quadriceps muscle and myelinated axons were assessed using electrophysiology and histology. The results showed that the specificity of motor axon regeneration (preferential reinnervation) was significantly higher when the nerve transection was treated by biodegradable conduit small gap tubulization and there was no significant difference between the two suture methods with respect to the functional and morphological recovery. This study demonstrated that the quicker and easier biodegradable conduit small gap tubulization may get more accurate reinnervation than traditional epineurial neurorrhaphy and produced functional and morphological recovery equal to traditional epineurial neurorrhaphy. PMID:25755828

Yu, Youlai; Zhang, Peixun; Yin, Xiaofeng; Han, Na; Kou, Yuhui; Jiang, Baoguo

2015-01-01

331

Suitability of boron-nitride single-walled nanotubes as fluid-flow conduits in nano-valve applications  

Energy Technology Data Exchange (ETDEWEB)

Molecular-level simulations are used to examine the suitability of boron-nitride single-walled nanotubes (SWNTs) as fluid-flow conduits in the nano-valve applications based on a molecular-mono-layer functionalized silicon cantilever. The interaction between the constituent atoms in the nanotubes is modeled using the Universal Force Field inter-atomic potential. Key functional requirements (a large range of nanotube radii with a stable circular cross section, a low level of strain energy in the nanotube at the onset of bending-induced buckling, relatively high compliance with respect to the radial breathing mode and a low value of nanotube/fluid-molecule binding energy) have been identified for nanotube fluid-flow conduits. The results obtained suggest that boron-nitride SWNTs do not offer any significant functional advantage over their carbon-based counterparts when used in fluid-flow conduit applications. The results also suggests that several of the nanotube properties obtained through the use of the Universal Force Field are quite comparable to their counterparts based on the first-principles quantum-mechanical calculations.

Grujicic, M. [Department of Mechanical Engineering, Program in Materials Science and Engineering, Clemson University, 241 Fluor Daniel, Engineering Innovation Building, Clemson, SC 29634-0921 (United States)]. E-mail: mica.grujicic@ces.clemson.edu; Cao, G. [Department of Mechanical Engineering, Program in Materials Science and Engineering, Clemson University, 241 Fluor Daniel, Engineering Innovation Building, Clemson, SC 29634-0921 (United States); Roy, W.N. [Army Research Laboratory, Processing and Properties Branch, Aberdeen, Proving Ground, MD 21005-5069 (United States)

2005-06-15

332

Suitability of boron-nitride single-walled nanotubes as fluid-flow conduits in nano-valve applications  

International Nuclear Information System (INIS)

Molecular-level simulations are used to examine the suitability of boron-nitride single-walled nanotubes (SWNTs) as fluid-flow conduits in the nano-valve applications based on a molecular-mono-layer functionalized silicon cantilever. The interaction between the constituent atoms in the nanotubes is modeled using the Universal Force Field inter-atomic potential. Key functional requirements (a large range of nanotube radii with a stable circular cross section, a low level of strain energy in the nanotube at the onset of bending-induced buckling, relatively high compliance with respect to the radial breathing mode and a low value of nanotube/fluid-molecule binding energy) have been identified for nanotube fluid-flow conduits. The results obtained suggest that boron-nitride SWNTs do not offer any significant functional advantage over their carbon-based counterparts when used in fluid-flow conduit applications. The results also suggests that several of the nanotube properties obtained through the use of the Universal Force Field are quite comparable to their counterparts based on the first-principles quantum-mechanical calculations

333

Thrombus formation within the right ventricle-to-pulmonary artery conduit (Sano shunt) as a cause of acute cyanosis in a patient with hypoplastic left heart syndrome.  

Science.gov (United States)

We describe a case of thrombus formation within a right ventricle-to-pulmonary artery conduit (Sano shunt) in a patient with hypoplastic left heart syndrome with resulting acute cyanosis and hypotension requiring emergency balloon angioplasty. PMID:17676367

Recto, M R; Sobczyk, W L; Austin, E H

2008-05-01

334

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

335

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.)

336

Enhanced Femoral Nerve Regeneration After Tubulization with a Tyrosine-Derived Polycarbonate Terpolymer: Effects of Protein Adsorption and Independence of Conduit Porosity  

OpenAIRE

Following complete nerve transection, entubulation of the nerve stumps helps guide axons to reconnect distally. In this study, a biodegradable and noncytotoxic tyrosine-derived polycarbonate terpolymer composed of 89.5?mol% desaminotyrosyl tyrosine ethyl ester (DTE), 10?mol% desaminotyrosyl tyrosine (DT), and 0.5?mol% poly(ethylene glycol) (PEG, molecular weight [Mw]=1?kDa) [designated as E10-0.5(1K)] was used to fabricate conduits for peripheral nerve regeneration. These conduits wer...

Ezra, Mindy; Bushman, Jared; Shreiber, David; Schachner, Melitta; Kohn, Joachim

2013-01-01

337

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

OpenAIRE

We developed a microfibrous poly(L-lactic acid) (PLLA) nerve conduit with a three-layered structure to simultaneously enhance nerve regeneration and prevent adhesion of surrounding tissue. The inner layer was composed of PLLA microfiber containing 25% elastin-laminin mimetic protein (AG73-(VPGIG)30) that promotes neurite outgrowth. The thickest middle layer was constructed of pure PLLA microfibers that impart the large mechanical stremgth to the conduit. A 10% poly(ethylene glycol) was added...

TetsujiYamaoka; MidoriNakayama

2014-01-01

338

33 CFR 154.808 - Vapor control system, general.  

Science.gov (United States)

...2010-07-01 2010-07-01 false Vapor control system, general. 154.808 Section 154.808...TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.808 Vapor control system, general. (a) A vapor...

2010-07-01

339

33 CFR 154.826 - Vapor compressors and blowers.  

Science.gov (United States)

...screw-type compressor handles vapor in the vapor collection system, it must... (2) Excessive cooling water temperature; (3) Excessive...temperatures. (c) If a liquid ring-type compressor handles vapor in the vapor...

2010-07-01

340

Vapor Pressure Measurements in a Closed System  

Science.gov (United States)

An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

Iannone, Mark

2006-01-01

341

Emissions of mercury vapor from tree bark  

Science.gov (United States)

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

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

342

A new model for bubble growth, deformation and coalescence for conduit dynamics  

Science.gov (United States)

The buoyancy of bubbles and the conditions under which they grow (equilibrium vs disequilibrium) control the behavior of the magma during volcanic eruptions. The high vesicularity measured in pumices deposited during explosive eruptions indicates that fragmentation generally occurs at high bubble volume fractions (>0.6). It therefore suggests that dynamical processes associated with high bubble volume fraction, such as bubble-bubble hydrodynamic interactions (deformation), coalescence, and differential bubble growth, can exert an important control on the eruption. We propose a new bubble dynamics model that focuses on bubble growth, bubble-bubble interactions and coalescence at high vesicularity. This model is based on multiphase flow calculations using a free surface lattice Boltzmann model. At the present time, the model is 2D and allows us to track the evolution of a few hundred bubbles distributed heterogeneously in space and growing from a supersaturated melt (sudden or continuous decompression are possible). A key feature of the model is its ability to accurately solve bubble deformation and coalescence under decompression and/or shear flow conditions. Coalescence, in our model, is calibrated against new laboratory experiments of bubble ascent under a free surface (see Chinh et al. abstract, this AGU meeting). We present numerical results for the evolution of the bubble size distribution (and its different statistical moments) as a consequence of decompression, as well as shear deformation. We also compute the distribution of gas pressure in the heterogeneous bubble population. The model is used to construct a new parameterizations to account for (1) hydrodynamic forces resulting from bubble interactions applied on the silicate melt (drag), and, (2) the evolution of the heterogeneous distribution of bubble size and pressure. Lastly, we discuss how these parameterizations can be incorporated in conduit flow models to solve for the evolution of the multiphase magma mixture more accurately, as it approaches fragmentation conditions.

Huber, C.; Nguyen, C.; Dufek, J.; Gonnermann, H. M.

2011-12-01

343

Vapor separating vessel in upright configuration for a nuclear reactor plant  

International Nuclear Information System (INIS)

With the vertical vapor separating vessel there is achieved the separation of liquid droplets from radioactive vapor with a stripping factor of 10-9. It consists essentially of a lower part containing the vapor/water mixture and an upper part where two separators are arranged one above the other. These consist of two each corrugated droplet separators and an agglomerator lying in between. The latter consists of a fine network of wise, ganze or the like. The droplet separator as well as the agglomerator may be cleaned from salts and solids by means of cleaning nozzles and cleaning agents. (RW)

344

High temperature vapors science and technology  

CERN Document Server

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

Hastie, John

2012-01-01

345

Absorption spectroscopic investigation of rhodamine dye vapors  

Science.gov (United States)

The dyes rhodamine 6G and rhodamine 19 are investigated. The dye stability versus temperature and time is studied. Bulk dye stuff is found to be less stable than dye adsorbed to the stainless steel cell walls and in the vapor phase. Rhodamine 6G converts to rhodamine 19 before evaporation. Adsorbed rhodamine 19 and rhodamine 19 vapor disintegrate most likely into 2,7-dimethylrhodamine 110 at elevated temperatures (> 320°C). For rhodamine 19 vapor the absorption spectrum, the saturated vapor density and the latent heat of evaporation are determined. The vapor absorption spectra of rhodamine 19 and 2,7-dimethylrhodamine 110 are compared with solution spectra.

Weininger, H.; Schmidt, J.; Penzkofer, A.

1989-02-01

346

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

CERN Document Server

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

Otarola, Angel C; Kerber, Florian

2011-01-01

347

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

Directory of Open Access Journals (Sweden)

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

Mina Mehregan

2014-02-01

348

Water vapor and methane in the upper stratosphere - An examination of some of the Nimbus 7 measurements  

Science.gov (United States)

The zonal mean volume mixing ratios of water vapor and methane from January to May, 1979, derived from the Nimbus-7 limb IR monitor of the stratosphere and from stratosphere and mesosphere sounder experiments are investigated. The water vapor mixing ratio of air that enters the stratosphere from the troposphere and the yield of water vapor from photochemical oxidation of methane in the stratosphere are examined. The water vapor yield averaged between 1.5 and 2.0, although variability with time and level was relatively large. It is suggested that water vapor yield increases with height in the 16- to 3-mbar range. The average water vapor mixing ratio fo air entering the stratosphere during the study period was about 3.25 X 10 to the -6th.

Hansen, Anthony R.; Robinson, G. D.

1989-01-01

349

Vaporization of In2Te3(s)  

International Nuclear Information System (INIS)

The vaporization chemistry of In2Te3(s) was studied by the computerautomated simultaneous Knudsen-effusion and torsion-effusion method, by high-temperature mass spectrometry, and by ancillary methods. The first absolute measurements of the vapor pressure of In2Te3 are reported. In2Te3(s) vaporized incongruently in the temperatue range 701-889 K and produced Te2(g) and a solid-solution, (Xsub(In)=0.42 and Xsub(Te)=0.58). The standard enthalpy of the reaction at 298 K, ?H0 (298 K) by the third-law method was 136.0 +- 0.3 kJ/mol of vapor. The above solid solution vaporized incongruently and produced in InTe(s) and a vapor which consisted of Te2(g) and In2Te(g). InTe(s) vaporized congruently in the range 701-887 K and produded Te2(g) and In2Te(g); the third-law ?H0sub(?) (298 K) was 201.5 +- 1.0 kJ/mol. These results were at variance with the literature on vaporization of In2Te3(s) where both congruent vaporization and incongruent vaporization to give InTe(s) are separately reported. Further, InTe(s) was reported to vaporize incongruently. These differences are discussed. (Author)

350

(VDA) Vapor Diffusion Apparatus Tray  

Science.gov (United States)

These Vapor Diffusion Apparatus (VDA) trays were first flown in the Thermal Enclosure System (TES) during the USMP-2 (STS-62) mission. Each tray can hold 20 protein crystal growth chambers. Each chamber contains a double-barrel syringe; one barrel holds protein crystal solution and the other holds precipitant agent solution. During the microgravity mission, a torque device is used to simultaneously retract the plugs in all 20 syringes. The two solutions in each chamber are then mixed. After mixing, droplets of the combined solutions are moved onto the syringe tips so vapor diffusion can begin. During the length of the mission, protein crystals are grown in the droplets. Shortly before the Shuttle's return to Earth, the experiment is deactivated by retracting the droplets containing protein crystals, back into the syringes.

1994-01-01

351

RTE with Li vapor target  

International Nuclear Information System (INIS)

High resolution projectile Auger electron spectorscopy is being used to measure cross sections for resonant transfer and excitation (RTE) as a function of projectile energy, in collisions of highly charged ions with a lithium vapor target. Previously H2 and He have been used as targets for RTE studies via high resolution projectile Auger electron spectroscopy. With Li as a target we expect to see the effect of the loosely bound valence electron manifested as a narrow resonance peak sitting on the broader peak of the 1s electrons. By using Li-like F and O projectile, direct comparison of resonance line shapes can be made with previously obtained RTE cross section, using a He target. Extension of the technique is being made to laser-excited Li-vapor target. Progress on this aspect of the experiment will be presented. (orig.)

352

Sodium vapor charge exchange cell  

International Nuclear Information System (INIS)

An operational sequential charge-exchange ion source yielding a 50 MeV H- current of approximately 8 mA is planned for use with the Argonne 500 MeV booster synchrotron. We report on the progress for development of a sodium vapor charge-exchange cell as part of that planned effort. Design, fabrication, and operating results to date are presented and discussed. (author)

353

Internal Water Vapor Photoacoustic Calibration  

Science.gov (United States)

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

Pilgrim, Jeffrey S.

2009-01-01

354

Evaporation by mechanical vapor recompression  

Science.gov (United States)

Progress in the development of a study of the application of the technologies of mechanical vapor recompression and falling film evaporation as applied to the beet sugar industry is reported. Progress is reported in the following areas: technical literature search; report on visit to European factories using these technologies; energy balance studies of factories offered by the industry as candidates for the demonstration plants; and report on energy balance studies and the recommendations as to the site for the demonstration plant.

Iverson, C. H.; Coury, G. E.

1980-04-01

355

Dependence of Vapor Void Fraction on Fundamental Bubble Parameters in Subcooled Flow Boiling  

International Nuclear Information System (INIS)

A visual study of water subcooled flow boiling was conducted to clarify the mechanism of triggering the net vapor generation (NVG). The test section was a transparent sapphire grass tube of 20 mm in inside diameter; a high-speed camera was used to capture the behavior of vapor bubbles. In the present experiments, the vapor void fraction in the heated tube was expressed as the function of the following bubble parameters: nucleation site density, frequency of bubble release, bubble lifetime, and bubble size. Among these four bubble parameters, the bubble size had a particularly strong influence on the vapor void fraction: the void fraction was approximately proportional to the forth power of mean bubble diameter. Consequently, mean bubble diameter should be large enough for the vapor void fraction to increase rapidly with the wall heat flux. In low flowrate experiments, bubbles generated at nucleation sites were relatively large at the onset of nucleate boiling (ONB). The heat flux at ONB hence appeared the reasonable approximation of that at NVG. Whereas, in high flowrate experiments, bubbles were small at ONB and much higher heat flux was necessary to obtain large bubbles. Thus, the heat flux required to trigger NVG was much higher than that at ONB. It was concluded in the present experimental conditions that accurate evaluation of mean bubble diameter was of significant importance in predicting the onset of net vapor generation. (authors)on. (authors)

356

Low power gold vapor laser  

International Nuclear Information System (INIS)

In this study, the design of a low power gold vapor laser is presented. The laser tube is an alumina ceramic of cylindrical shape, having the length of 58cm and the inner bore diameter of 11mm. The maximum applied DC voltage is 4.2kV, and the average current is ? 390mA. The system is operating at the pulse repetition rate of 18.2 kHz, with 40 mbar neon gas pressure. The maximum measured output power in sealed off and gas flow conditions are 710 and 450mW, respectively. The operational behavior of the present system has been compared with that of a copper vapor laser of the same dimensions, showing that the power efficiency is much lower in the case of the gold vapor laser. While both systems have similar time behavior and introducing similar response to the operational gas pressure, it seems, however, the laser output powers versus the pulse repetition rate are different in each laser. The measured output power versus the neon gas pressure has a maximum at 60 mbar gas pressure with a cutoff which occurs at 170 mbar

357

Single droplet vapor explosion experiments  

International Nuclear Information System (INIS)

In a postulated severe accident in a light water reactor, molten fuel may contact a pool of coolant either in-vessel or ex-vessel. This contact may become an explosive interaction testing the mechanical strength of the reactor vessel and/or the containment building. When a vapor explosion occurs, hot material rapidly fragments resulting in a dramatic increase in the fuel surface area and hence the heat transfer rate. Since a single droplet explosion is considered to be a unit cell of the intermediate or large scale vapor explosion, many past researchers have used this small scale experiment to investigate the vapor explosion triggering behavior and its possible fragmentation mechanism. Some initial conditions for these past experiments are summarized. In most cases water was used as a coolant material. A number of metal or metal oxides were used as simulant fuels, e.g., lead, tin, bismuth, iron-oxides and UO/sub 2/. In this paper the authors describe the baseline experimental results in which iron-oxide droplets of about 75 mg at 19000C are injected into a large water pool of about 4 kg at 150C. They also discuss scoping experiments in which mass of the iron-oxide droplets and viscosity of the coolant were varied

358

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

Directory of Open Access Journals (Sweden)

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

Daniel Navia

2005-03-01

359

Satellite radar data reveal short-term pre-explosive displacements and a complex conduit system at Volcán de Colima, Mexico  

Directory of Open Access Journals (Sweden)

Full Text Available The geometry of the volcanic conduit is a main parameter controlling the dynamics and the style of volcanic eruptions and their precursors, but also one of the main unknowns. Pre-eruptive signals that originate in the upper conduit region include seismicity and deformation of different types and scales. However, the locality of the source of these signals and thus the conduit geometry often remain unconstrained at steep sloped and explosive volcanoes due to the sparse instrumental coverage in the summit region and difficult access. Here we infer the shallow conduit system geometry of Volcán de Colima, Mexico, based on ground displacements detected in high resolution satellite radar data up to seven hours prior to an explosion in January 2013. We use Boundary Element Method modeling to reproduce the data synthetically and constrain the parameters of the deformation source, in combination with an analysis of photographs of the summit. We favour a two-source model, indicative of distinct regions of pressurization at very shallow levels. The location of the upper pressurization source coincides with that of post-explosive extrusion; we therefore attribute the displacements to transient (elastic pre-explosive pressurization of the conduit system. Our results highlight the geometrical complexity of shallow conduit systems at explosive volcanoes and its effect on the distribution of pre-eruptive deformation signals. An apparent absence of such signals at many explosive volcanoes may relate to its small temporal and spatial extent, partly controlled by upper conduit structures. Modern satellite radar instruments allow observations at high spatial and temporal resolution that may be the key for detecting and improving our understanding of the generation of precursors at explosive volcanoes.

Jacqueline T. Salzer

2014-06-01

360

Baltimore Canyon as a modern conduit of sediment to the deep sea  

Science.gov (United States)

An integrated study using moored current meters, transmissometers and sediment traps revealed that sediment in Baltimore Canyon was resuspended regularly when energy from internal tides was focused along the canyon axis. Such focusing occurred primarily during late winter and early spring. During resuspension events particle concentrations at 275 m in the canyon axis typically increased from a background level of 100 ?g l -1 to over 1000 ?g l -1 within a 5-min period and often exceeded 5000 ?g l -1. Net transport of both water and sediment 5 m above bottom (mab) at 275 m in the canyon axis was consistently downcanyon, while 5 mab at 600 m in the canyon axis net transport was upcanyon, implying convergence between the two sites. The distribution of suspended sediment was determined using a CTD/transmissometer during hydrographic transects along the canyon axis and across the slope adjacent to either side of the canyon. Resuspension on the shelf, canyon walls, and along the slope was minimal, but in the canyon interleaving tongues of turbid water were always present between 200 and 800 m. Although concentrations of resuspended sediment were high, they were not sufficient to generate downcanyon flows. Turbid plumes moved seaward along density surfaces at the convergence between 275 and 600 m and other regions of the canyon. The passage of atmospheric storms and Gulf Stream rings may have changed the pattern of currents of resuspension in portions of the canyon sometimes, but not always. Fluxes of particles collected in sediment traps along the canyon axis increased exponentially toward the buttom, but the size of particles collected in traps decreased with distance from the canyon head, suggesting that resuspended sediment was advected, but depleted in larger, denser particles away from the canyon. An exponential increase with depth in trap fluxes at 1000 m, despite fairly uniform concentrations of suspended particles measured by transmissometers, suggests that many particles are advected as large aggregates (marine snow) that are not detected quantitatively by transmissometers. Currents outside the canyon walls quickly dilute and dissipate sediment moving out of the canyon. Subamrine canyons can act as conduits of sediment to the deep ocean not only by channeling turbidity currents, but also by focusing internal tides that resuspended sediment, after which it is advected to deeper water.

Gardner, Wilford D.

1989-03-01

361

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

International Nuclear Information System (INIS)

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

362

Observation system simulation experiments using water vapor isotope information  

Science.gov (United States)

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

Yoshimura, Kei; Miyoshi, Takemasa; Kanamitsu, Masao

2014-07-01

363

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

Science.gov (United States)

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

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

2014-07-01

364

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

Directory of Open Access Journals (Sweden)

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

TetsujiYamaoka

2014-07-01

365

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

Science.gov (United States)

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

Roell, Marilee M.; Fu, Rong

2008-01-01

366

Two-dimensional condensing vapor flow on parallel flat plates in an enclosure  

Science.gov (United States)

A vapor flow of pure fluid condensing onto a vertical flat plate in an enclosure was examined in order to develop knowledge of the mechanism of vapor condensation and flowfield characteristics. A specific Pyrex glass thermosyphon-like container filled with a certain amount of pure fluid, with or without noncondensable gas, was heated and the upward vapor flow between a pair of cooled parallel plates installed in the upper portion of the container was investigated by means of temperature and pressure sensors as well as laser holographic interferometry. With a pure fluid only (single-component, two-phase flow) in the container, the entire flowfield of condensation region is uniform in density and temperature. On the other hand, with a pure fluid containing a noncondensable gas (two-component, two-phase flow), a distinct flowfield structure is obtained. Its characteristics are: (1) the flowfield in the vapor/gas mixing region has a clear interfacial layer in the longitudinal or axial direction and a rather thick boundary layer near the cooled plate; (2) the condensing vapor flow has an oscillatory character with a low frequency of around 1 Hz, even in the steady-state flow and thermal conditions; and (3) sharp pressure drop was observed at the initiation of nonequilibrium vapor condensation when a large temperature difference existed between the vapor and the cooled plates.

Kobayashi, Yasunori; Matsumoto, Tsuyoshi

1987-04-01

367

Water vapor and the dynamics of climate changes  

CERN Document Server

Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus climate. Here we present an overview of how latent heat release affects atmosphere dynamics in a broad range of climates, ranging from extremely cold to extremely warm. Contrary to widely held beliefs, atmospheric circulation statistics can change non-monotonically with global-mean surface temperature, in part because of dynamic effects of water vapor. For example, the strengths of the tropical Hadley circulation and of zonally asymmetric tropical circulations, as well as the kinetic energy of extratropical baroclinic eddies, can be lower than they presently are both in much warmer climates and in much colder climates. We discuss how latent heat release is implicated in such circulation changes, particularly through its effect on the atmospheric static stability, and we illustrate the circul...

Schneider, Tapio; Levine, Xavier

2009-01-01

368

Water vapor diffusion membrane development  

Science.gov (United States)

A total of 18 different membranes were procured, characterized, and tested in a modified bench-scale vapor diffusion water reclamation unit. Four membranes were selected for further studies involving membrane fouling. Emphasis was placed on the problem of flux decline due to membrane fouling. This is discussed in greater details under "Summary and Discussion on Membrane Fouling Studies" presented in pages 47-51. The system was also investigated for low temperature application on wash-water where the permeated water is not recovered but vented into space vacuum.

Tan, M. K.

1976-01-01

369

Microwave assisted chemical vapor infiltration  

International Nuclear Information System (INIS)

A microwave assisted process for production of continuous fiber reinforced ceramic matrix composites is described. A simple apparatus combining a chemical vapor infiltration reactor with a conventional 700 W multimode oven is described. Microwave induced inverted thermal gradients are exploited with the ultimate goal of reducing processing times on complex shapes. Thermal gradients in stacks of SiC (Nicalon) cloths have been measured using optical thermometry. Initial results on the ''inside out'' deposition of SiC via decomposition of methyltrichlorosilane in hydrogen are presented. Several key processing issues are identified and discussed. 5 refs

370

Continuously differentiable means  

Directory of Open Access Journals (Sweden)

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

Fujii Masatoshi

2006-01-01

371

Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone  

Science.gov (United States)

The response of water in the unsaturated zone to seasonal changes of temperature (T) is determined analytically using the theory of nonisothermal water transport in porous media, and the solutions are tested against field observations of moisture potential and bomb fallout isotopic (36Cl and3H) concentrations. Seasonally varying land surface temperatures and the resulting subsurface temperature gradients induce thermal vapor diffusion. The annual mean vertical temperature gradient is close to zero: however, the annual mean thermal vapor flux is downward, because the temperature-dependent vapor diffusion coefficient is larger, on average, during downward diffusion (occurring at high T) than during upward diffusion (low T). The annual mean thermal vapor flux is shown to decay exponentially with depth; the depth (about 1 m) at which it decays to ??-1 of its surface value is one half of the corresponding decay depth for the amplitude of seasonal temperature changes. This depth-dependent annual mean flux is effectively a source of water, which must be balanced by a flux divergence associated with other transport processes. In a relatively humid environment the liquid fluxes greatly exceed the thermal vapor fluxes, so such a balance is readily achieved without measurable effect on the dynamics of water in the unsaturated zone. However, if the mean vertical water flux through the unsaturated zone is very small (water. This return flux may include both vapor and liquid components. Below any near-surface zone of weather- related fluctuations of matric potential, maintenance of this upward flux requires an increase with depth in the annual mean matric potential; this theoretical prediction is supported by long-term field measurements in the Chihuahuan Desert. The analysis also makes predictions, confirmed by the field observations, regarding the seasonal variations of matric potential at a given depth. The conceptual model of unsaturated zone water transport developed here implies the possibility of near-surface trapping of any aqueous constituent introduced at the surface.

Milly, P.C.D.

1996-01-01

372

Concomitant adsorption and desorption of organic vapor in dry and humid air streams using microwave and direct electrothermal swing adsorption.  

Science.gov (United States)

Industrial gas streams can contain highly variable organic vapor concentrations that need to be processed before they are emitted to the atmosphere. Fluctuations in organic vapor concentrations make it more difficult to operate a biofilter when compared to a constant vapor concentration. Hence, there is a need to stabilize the concentration of rapidly fluctuating gas streams for optimum operation of biofilters. This paper describes new concomitant adsorption desorption (CAD) systems used with variable organic vapor concentration gas streams to provide the same gas stream, but at a user-selected constant vapor concentration that can then be more readily processed by a secondary air pollution control device such as a biofilter. The systems adsorb organic vapor from gas streams and simultaneously heat the adsorbent using microwave or direct electrothermal energy to desorb the organic vapor at a user-selected set-point concentration. Both systems depicted a high degree of concentration stabilization with a mean relative deviation between set-point and stabilized concentration of 0.3-0.4%. The direct electrothermal CAD system was also evaluated to treat a humid gas stream (relative humidity = 85%) that contained a variable organic vapor concentration. The high humidity did not interfere with CAD operation as water vapor did not adsorb but penetrated through the adsorbent These results are important because they demonstrate the ability of CAD to effectively dampen concentration fluctuation in gas streams. PMID:19174910

Hashisho, Zaher; Emamipour, Hamidreza; Rood, Mark J; Hay, K James; Kim, Byung J; Thurston, Deborah

2008-12-15

373

A mechanical and computational investigation on the effects of conduit orientation on the strength of massive bone allografts.  

Science.gov (United States)

Structural bone allografts are used to reconstruct large skeletal defects resulting from trauma, tumor resection, or revision arthroplasty. Though used for over a century, bone allografts suffer from a high rate of mechanical failure due to limited graft revitalization even after extended periods in vivo. The current study evaluated the mechanical properties of longitudinally perforated cortical bone allografts (LAP) that have been shown to promote accelerated graft incorporation in a large animal model. The compressive and tensile properties of longitudinally perforated allograft specimens, as determined through uniaxial compression and diametral compression tests, respectively, were not significantly affected by the presence of the conduit. However, transversely perforated grafts (TAP) demonstrated a marked decrease in tensile capacity (p=0.04). Finite element analysis demonstrated moderate increases in the maximum principal stresses in LAP specimens while TAP models indicated an 83.4% increase in maximum principle stress near the conduit on the endosteal surface of the graft. This research and the previous in vivo study suggest that LAP adequately serves as an internal template within the cortical bone allograft for osseous apposition and revitalization without adversely affecting the structural or mechanical integrity of the graft. PMID:17765025

Santoni, Brandon G; Womack, Wesley J; Wheeler, Donna L; Puttlitz, Christian M

2007-11-01

374

Micro-structural geometry of thin films intended for the inner lumen of nerve conduits affects nerve repair.  

Science.gov (United States)

Damage to peripheral nerves can cause significant motor or sensory injuries. In serious cases, a nerve is sacrificed from another part of the body to repair a damaged nerve (autograft). The development of biodegradable polymer conduits may offer an alternative to autografts. This study investigated the surface topography and mechanical properties of smooth, pitted and grooved structures of ultra-thin poly (?-caprolactone)/poly lactic acid blended, solvent-cast films. We have investigated the effect of the groove shape on cell morphology and alignment. Photolithography and dry/wet etching was used to develop patterned silicon substrates with grooves with accurate geometries (V shaped, sloped walls and square shaped). Using a neural cell line (NG108-15), in vitro experiments confirmed good cell attachment and proliferation on all the polymer scaffolds. Imaging techniques demonstrated that there was different cellular responses and morphology according to the shape of the groove. Studies showed that the geometry, particularly the angle of the slope and the space between grooves, affected cellular responses. In addition, biomechanical studies showed that the patterned films had excellent mechanical properties and were stronger than the natural nerve. The conduit tubes were made by rolling the films around a mandrel and using a thermal welding technique to join the edges. The promising biomechanical and in vitro results demonstrate that nerve cell responses are affected by the shape of longitudinal grooves, and particularly by the angle of the slope of the groove walls. PMID:23572143

Mobasseri, S A; Terenghi, G; Downes, S

2013-07-01

375

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

Science.gov (United States)

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

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

2012-11-01

376

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

CERN Document Server

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

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

2005-01-01

377

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

CERN Document Server

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

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

2004-01-01

378

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

Science.gov (United States)

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

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

2015-01-01

379

Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges  

Directory of Open Access Journals (Sweden)

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

Dora M. Paolucci

2011-03-01

380

Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges  

OpenAIRE

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

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

2011-01-01

381

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

International Nuclear Information System (INIS)

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

382

Effects of carbon dioxide in the coupled conduit plus atmospheric dispersal dynamics of the 4400 BP Agnano Monte Spina eruption of Phlegrean Fields  

Science.gov (United States)

The influence of carbon dioxide on the dynamics of sustained explosive eruptions was investigated with reference to the 4400 BP Agnano Monte Spina eruption which represents the highest intensity event in the last cycle of activity of the Phlegrean Fields Caldera. Conduit flow and dispersal dynamics were coupled through the flow conditions at the conduit outlet in order to investigate the net influence on carbon dioxide content on the eruptive style. Conduit flow was described by the steady-state, one-dimensional, and multiphase flow model of Papale (2001) whereas the transient, two-dimensional, multiphase flow model of Neri et al. (2003) was employed in the simulation of atmospheric dispersal. Two sustained magmatic phases of the eruption, corresponding to layers B1 and D1, were selected for the simulations. The effect of the presence of a two-component gas phase was investigated through a parametric study on the CO2/H2O ratio that was allowed to vary from 0 up to 0.5 at constant water content or constant total volatile content. The low solubility of carbon dioxide has a significant effect on the distribution of the flow variables in the conduit as well as in the location of the exsolution and fragmentation levels. In particular, even small amounts of CO2 result in separation of a gas phase in the magma chamber. Viceversa, upper conduit profiles, vent conditions, and computed conduit diameter are only slightly affected at constant mass flow-rate of the eruption. Simulations of dispersal dynamics using the computed vent conditions also indicated that, in the specific range of investigation, the addition of CO2 does not significantly change the eruptive style of the column as can be deduced by the total percentage of pyroclasts forming the density currents in the different cases.

Esposti Ongaro, T.; del Seppia, D.; Papale, P.; Neri, A.; Polacci, M.

2003-04-01

383

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

Science.gov (United States)

Regeneration and functional reconstruction of peripheral nerve defects remained a significant clinical challenge. Nerve guide conduits, with seed cells or neurotrophic factors (NTFs), had been widely used to improve the repair and regeneration of injured peripheral nerve. Pyrroloquinoline quinone (PQQ) was an antioxidant that can stimulate nerve growth factors (NGFs) synthesis and accelerate the Schwann cells (SCs) proliferation and growth. In present study, three kinds of nerve guide conduits were constructed: one from cellulose/SPI hollow tube (CSC), another from CSC combined with SCs (CSSC), and the third one from CSSC combined with PQQ (CSSPC), respectively. And then they were applied to bridge and repair the sciatic nerve defect in rats, using autograft as control. Effects of different nerve guide conduits on the nerve regeneration were comparatively evaluated by general analysis, sciatic function index (SFI) and histological analysis (HE and TEM). Newly-formed regenerative nerve fibers were observed and running through the transparent nerve guide conduits 12 weeks after surgery. SFI results indicated that the reconstruction of motor function in CSSPC group was better than that in CSSC and CSC groups. HE images from the cross-sections and longitudinal-sections of the harvested regenerative nerve indicated that regenerative nerve fibers had been formed and accompanied with new blood vessels and matrix materials in the conduits. TEM images also showed that lots of fresh myelinated and non-myelinated nerve fibers had been formed. Parts of vacuolar, swollen and abnormal axons occurred in CSC and CSSC groups, while the vacuolization and swell of axons was the least serious in CSSPC group. These results indicated that CSSPC group had the most ability to repair and reconstruct the nerve structure and functions due to the comprehensive contributions from hollow CSC tube, SCs and PQQ. As a result, the CSSPC may have the potential for the applications as nerve guide conduits in the field of nerve tissue engineering. PMID:25580010

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

2015-02-20

384

On Mean Divergence Measures  

OpenAIRE

Arithmetic, geometric and harmonic means are the three classical means famous in the literature. Another mean such as square-root mean is also known. In this paper, we have constructed divergence measures based on nonnegative differences among these means, and established an interesting inequality by use of properties of Csiszar's f-divergence. Connections of new mean divergences measures with classical divergence measures such as Jeffreys-Kullback-Leibler J-divergence, Sibs...

Taneja, Inder Jeet

2005-01-01

385

Experimental study of flash boiling spray vaporization through quantitative vapor concentration and liquid temperature measurements  

Science.gov (United States)

Flash boiling sprays of liquid injection under superheated conditions provide the novel solutions of fast vaporization and better air-fuel mixture formation for internal combustion engines. However, the physical mechanisms of flash boiling spray vaporization are more complicated than the droplet surface vaporization due to the unique bubble generation and boiling process inside a superheated bulk liquid, which are not well understood. In this study, the vaporization of flash boiling sprays was investigated experimentally through the quantitative measurements of vapor concentration and liquid temperature. Specifically, the laser-induced exciplex fluorescence technique was applied to distinguish the liquid and vapor distributions. Quantitative vapor concentration was obtained by correlating the intensity of vapor-phase fluorescence with vapor concentration through systematic corrections and calibrations. The intensities of two wavelengths were captured simultaneously from the liquid-phase fluorescence spectra, and their intensity ratios were correlated with liquid temperature. The results show that both liquid and vapor phase of multi-hole sprays collapse toward the centerline of the spray with different mass distributions under the flash boiling conditions. Large amount of vapor aggregates along the centerline of the spray to form a "gas jet" structure, whereas the liquid distributes more uniformly with large vortexes formed in the vicinity of the spray tip. The vaporization process under the flash boiling condition is greatly enhanced due to the intense bubble generation and burst. The liquid temperature measurements show strong temperature variations inside the flash boiling sprays with hot zones present in the "gas jet" structure and vortex region. In addition, high vapor concentration and closed vortex motion seem to have inhibited the heat and mass transfer in these regions. In summary, the vapor concentration and liquid temperature provide detailed information concerning the heat and mass transfer inside flash boiling sprays, which is important for the understanding of its unique vaporization process.

Zhang, Gaoming; Hung, David L. S.; Xu, Min

2014-08-01

386

Laser emission in thulium bromide vapor  

Energy Technology Data Exchange (ETDEWEB)

Laser emission due to atomic transitions in an REE under the dissociation of REE halide vapor in a pulsed discharge has been realized. Laser action due to Tm I transition at a wavelength of 1448 nm in thulium bromide vapor is studied. 6 refs.

Gerasimov, V.A.; Iunzhakov, B.P. (Institut Optiki Atmosfery, Tomsk (USSR))

1989-10-01

387

Vapor sampling and analysis plan. Revision 1  

International Nuclear Information System (INIS)

This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from both SST and DST tanks

388

LNG fire and vapor control system technologies  

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-06-01

389

Risk assessment of metal vapor arcing  

Science.gov (United States)

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

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

2009-01-01

390

ON-LINE CALCULATOR: VAPOR INTRUSION MODELING  

Science.gov (United States)

Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which may migrate through subsurface soils and may enter the indoor air of overlying build...

391

Internalized Meaning Factualism  

DEFF Research Database (Denmark)

The normative character of meaning creates deep problems for the attempt to give a reductive explanation of the constitution of meaning. I identify and critically examine an increasingly popular Carnap-style position, which I call Internalized Meaning Factualism (versions of which I argue are defended by, e.g., Robert Brandom, Paul Horwich and Huw Price), that promises to solve the problems. According to this position, the problem of meaning can be solved by prohibiting an external perspective on meaning constituting properties. The idea is that if we stick to a perspective on meaning that is internal to meaning discourse, then we can preserve the normativity of meaning and yet locate meaning in the natural world. I develop a generic motivation for this position, but argue that, since this motivation is consistent with the Ramsey-Carnap-Lewis-Jackson reductionist strategy, internalized meaning factualism is unstable. The problems about the normativity of meaning can therefore not be sidestepped in this way.

Hohwy, Jakob

2006-01-01

392

Autophobic dewetting of a poly(methyl methacrylate) thin film on a silicon wafer treated in good solvent vapor.  

Science.gov (United States)

The wettability of thin poly(methyl methacrylate) (PMMA) films on a silicon wafer with a native oxide layer exposed to solvent vapors is dependent on the solvent properties. In the nonsolvent vapor, the film spread on the substrate with some protrusions generated on the film surface. In the good solvent vapor, dewetting happened. A new interface formed between the anchored PMMA chains and the swollen upper part of the film. Entropy effects caused the upper movable chains to dewet on the anchored chains. The rim instability depended on the surface tension of solvent (i.e., the finger was generated in acetone vapor (gamma(acetone) = 24 mN/m), not in dioxane vapor (gamma(dioxane) = 33 mN/m)). The spacing (lambda) that grew as an exponential function of film thickness h scaled as approximately h(1.31), whereas the mean size (D) of the resulting droplets grew linearly with h. PMID:19278204

Xue, Longjian; Han, Yanchun

2009-05-01

393

Global exchange of water vapor on Mars  

Science.gov (United States)

Observations of the global distribution and seasonal variation of the Martian atmospheric water vapor have been made from the Viking orbiters for a continuous period covering more than half of a Martian year. The seasonal dependence of the latitude distribution of the column abundance of vapor is consistent with a model in which the vapor is in equilibrium with the regolith at polar and middle latitudes. The results indicate the existence of a permanent reservoir of water ice buried at a depth of 10 cm to 1 meter at all latitudes poleward of 40 deg. The behavior of the vapor in the summer hemisphere suggests an annual net transport of the vapor phase from the southern to the northern hemisphere, with deposition of ice of thickness on the order of a few milligrams per sq cm at northern polar latitudes. The hemispheric asymmetry is the result of the propagation of global dust storms originating in the south.

Farmer, C. B.

1978-01-01

394

Soil vapor extraction with dewatering  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-08-01

395

Copper vapor laser system development  

International Nuclear Information System (INIS)

High-power, high-quality, and long-life copper vapor laser (CVL) system has been developed and operated. The system is composed of a small sized CVL oscillator with high beam quality, several high-power CVL amplifiers and related sub-systems such as special resonator optics, beam shaping and propagating optics, and pulse timing controller. Further developments of high-power amplifiers are being conducted for the next R and D targets. In our latest tests, the maximum output power of 480W has been achieved by optimizing discharge circuit conditions. Major-components life-time of more than 2000 hours has been also ensured in long-term CVL amplifier operation tests. Accumulated operation time of more than 700 hours has been achieved without refilling copper source or any maintenance. (author)

396

An Overview on Thin Films Prepared by Chemical Vapor Deposition  

International Nuclear Information System (INIS)

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

397

Simulation of stratospheric water vapor and trends using three reanalyses  

Directory of Open Access Journals (Sweden)

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

M. R. Schoeberl

2012-03-01

398

Assessment of water vapor content from MIVIS TIR data  

Directory of Open Access Journals (Sweden)

Full Text Available The main objective of land remotely sensed images is to derive biological, chemical and physical parameters by inverting sample sets of spectral data. For the above aim hyperspectral scanners on airborne platform are a powerful remote sensing instrument for both research and environmental applications because of their spectral resolution and the high operability of the platform. Fine spectral information by MIVIS (airborne hyperspectral scanner operating in 102 channels ranging from VIS to TIR allows researchers to characterize atmospheric parameters and their effects on measured data which produce undesirable features on surface spectral signatures. These effects can be estimated (and remotely sensed radiances corrected if atmospheric spectral transmittance is known at each image pixel. Usually ground-based punctual observations (atmospheric sounding balloons, sun photometers, etc. are used to estimate the main physical parameters (like water vapor and temperature profiles which permit us to estimate atmospheric spectral transmittance by using suitable radiative transfer model and a specific (often too strong assumption which enable atmospheric properties measured only in very few points to be extended to the whole image. Several atmospheric gases produce observable absorption features, but only water vapor strongly varies in time and space. In this work the authors customize a self-sufficient «split-window technique» to derive (at each image pixel atmospheric total columnar water vapor content (TWVC using only MIVIS data collected by the fourth MIVIS spectrometer (Thermal Infrared band. MIVIS radiances have been simulated by means of MODTRAN4 radiative transfer code and the coefficients of linear regression to estimate TWVC from «split-windows» MIVIS radiances, based on 450 atmospheric water vapor profiles obtained by radiosonde data provided by NOAANESDIS. The method has been applied to produce maps describing the spatial variability of the water vapor columnar content along a trial scene. The procedure has been validated by means of the MIVIS data acquired over Venice and the contemporary radiosonde data. A discrepancy within 5% has been measured between the estimate of TWVC derived from the proposed self-sufficient split-window technique and the coincident radiosonde measurements. If confirmed by further analyses such a result will permit us to fully exploit MIVIS TIR capability to offer a more effective (at image pixel level and self-sufficient (no ancillary observations required way to obtain atmospherically corrected MIVIS radiances.

V. Tramutoli

2006-06-01

399

CFD MODELING OF ITER CABLE-IN-CONDUIT SUPERCONDUCTORS. PART V: COMBINED MOMENTUM AND HEAT TRANSFER IN RIB ROUGHENED PIPES  

International Nuclear Information System (INIS)

Computational Fluid Dynamics (CFD) techniques have been proposed and applied in a series of papers to analyze cable-in-conduit conductors (CICC) for the International Thermonuclear Experimental Reactor (ITER). Previous work on the pressure drop in the central channel of ITER CICC is extended here to the problem of combined heat and momentum transfer. The CFD model, solved by the FLUENT commercial code, is first validated against 2D and 3D data from compact heat exchangers, showing good agreement. The Colburn analogy between the friction factor f and the Nusselt number Nu is not verified in the considered 2D geometries, as shown by both experiment and simulation. The validated CFD model is finally applied to the 3D analysis of central channel-like geometries relevant for ITER CICC. It is shown that the heat transfer coefficient on the central channel side stays relatively close to the smooth-pipe (Dittus-Boelter) value

400

The effect of transverse stress on the critical current of Nb/sub 3/Sn cable-in-conduit superconductors  

International Nuclear Information System (INIS)

The authors have investigated the effects of transverse stress on the critical current of Nb/sub 3/Sn Cable-In-Conduit Conductors (CICC). The sensitivity of the critical current (I/sub c/) to applied stress at 12 T has been determined for CICC's with helium void fractions (f/sub He/) in the range of 0.25 - 0.4. I/sub c/ has been found to be a function transverse stress with good correlation to single wire data up to stress levels of 50 MPa. At higher stress levels the CICC's show significantly higher degradation with transverse stress. No clear correlation has been found between the stress sensitivity of I/sub c/ and f/sub He/. The results fall into a broad band suggesting that geometric factors, such as wire position within the cable bundle, exert a strong influence on the I/sub c/ vs. stress dependence