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1

Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 1: General principles and requirements  

CERN Document Server

ISO 5167-1:2003 defines terms and symbols and establishes the general principles for methods of measurement and computation of the flowrate of fluid flowing in a conduit by means of pressure differential devices (orifice plates, nozzles and Venturi tubes) when they are inserted into a circular cross-section conduit running full. ISO 5167-1:2003 also specifies the general requirements for methods of measurement, installation and determination of the uncertainty of the measurement of flowrate. It also defines the general specified limits of pipe size and Reynolds number for which these pressure differential devices are to be used. ISO 5167 (all parts) is applicable only to flow that remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. It is not applicable to the measurement of pulsating flow.

International Organization for Standardization. Geneva

2003-01-01

2

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

Science.gov (United States)

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

2010-07-01

3

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

Science.gov (United States)

...Alternative means of emission limitation: Connectors in gas/vapor service and light liquid...Alternative means of emission limitation: Connectors in gas/vapor service and light liquid...operator shall implement one of the connector monitoring programs specified in...

2010-07-01

4

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

5

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

CERN Document Server

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

International Organization for Standardization. Geneva

2003-01-01

6

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

International Nuclear Information System (INIS)

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

7

Study of wavepacket dynamics in rubidium vapor by means of time-frequency analysis  

Science.gov (United States)

Wavepackets are excited in rubidium vapor by intense ultrashort (˜100 fs) pulses centered at a wavelength of 620 nm or 770 nm. The generated atomic wavepackets are optically detected via a pump-probe experiment based on axially phase-matched parametric four-wave mixing (FWM). This nonlinear process results in coherent ultraviolet (UV) or violet emission that carries information about the relative number densities of the excited states. The frequency spectrum of the UV/violet signal intensity, recorded while varying the pump-probe time delay, shows the presence of quantum beats between energy levels involved in the FWM process. The time-frequency analysis of that temporal UV/violet data is done by means of the short-time Fourier transform that leads to retrieval of the temporal evolution of amplitude and phase of the quantum beats. The observed dynamics suggest that not only atomic but also molecular ( Rb*2 ) wavepackets are generated, and that the temporal history of the amplitude of the quantum beats reflects the production of the excited atomic fragments of Rb*2 dissociation. More precisely, changes in the Rb excited state number densities alter the third-order nonlinear susceptibility chi(3) of the Rb vapor, which affects generation of the output signal wave by FWM. Dissociation into several product states is detected, and their branching ratios are estimated. Thus, atomic wavepackets, combined with FWM, appear to be a sensitive new multichannel spectroscopic means to study the fundamental process of molecular dissociation.

Senin, Andrey Aleksandrovich

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

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

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

Science.gov (United States)

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.

Park, Chul

2013-09-01

11

Arrangement of heat conduits  

International Nuclear Information System (INIS)

Two conventional heat conducting systems are combined end to end in opposition, one end of the arrangement being exposed and sensitive to the temperature of one environment or object being monitored, whilst the heat furnished at the other end is intentionally controlled. The condensation sections adjacent to the respective heat conduits combine to form a common condensation area that is in turn coupled to an appropriate thermal dissipator. The temperature of the monitored end and that of the controlled end of the heat conducting arrangement each produce a vaporisation of the working fluid resulting in a flow of the respective vaporised fluids moving in opposite directions and which meet in the end to form an interaction interface in the common condensation area. The position of this interaction interface depends on the steam pressure in the respective heat conduits. These pressures depend in turn on the respective temperatures and thermal powers of the sources at the controlled and monitored ends of the heat conducting arrangement. This arrangement of heat conduits can be employed as a heat valve or heat bridge

12

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

Science.gov (United States)

...limitation: Connectors in gas/vapor service and light liquid service. 63.649...limitation: Connectors in gas/vapor service and light liquid service. ...for connectors in gas/vapor service and for connectors in light liquid service. The...

2010-07-01

13

Acoustic signal propagation characterization of conduit networks  

Science.gov (United States)

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

Khan, Muhammad Safeer

14

Method and device for separating gaseous or vaporous materials, especially isotopes, by means of separation nozzles  

International Nuclear Information System (INIS)

A method is provided for separating gaseous or vaporous substances, especially isotopes, with different molecular weights and/or different gas kinetic cross sections, in which the mixture of substances to be separated is passed through separation nozzles. One or more skimmer diaphragms project into the flow path of the substances and are used to separate and remove fractions of different compositions, and several separation systems consisting of nozzles and skimmer diaphragms are arranged in a cascade. The cascade generates partial streams which contain the mixture of substances to be separated. The partial streams can contain an additional gas with each partial stream containing different fractions of additional gas. When the partial streams generated within the cascade contain different fractions of additional gas, the partial streams are jointly fed to one of the separation nozzle systems in such a way as to generate a molar fraction gradient with respect to the additional gas which is opposed in direction to the molar fraction gradient being generated by the separation process within the nozzle. The partial streams can contain different compositions of the mixture of substances to be separated. When the partial streams generated within the cascade contain different compositions of the mixture of substances to be separated, the partial streams are jointly fed to one of the separation nozzle systems in such a way as to generate a molar fraction ratio with respect to the substances to be separated which is identical in direction with the molar fraction gradient being generated by the separation process within the nozzle. 27 claims, 13 figures

15

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

Science.gov (United States)

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

Song, DongSeob; Boutiouta, Seddik

2014-05-01

16

The CONDUIT Series in Physics.  

Science.gov (United States)

CONDUIT distributes eight packages of computer-based instructional materials in its physics series; three are simulations of physical phenomena, and the others require students to write programs to solve physics problems. Specialized versions are being developed for microcomputers with graphical output and modern computer languages. (CMV)

Peters, H. J.

1980-01-01

17

Artificial conduits in reconstructive microsurgery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis describes experimental studies focussed on the elucidation of the function, healing, and performance of artificial conduits used to restore the continuity of small vessels and nerves, thus moving us another step further in realizing reliable readily available synthetic alternatives for clinical application. ... Zie: Summary and conclusions

Robinson, Peter Hague

1989-01-01

18

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

19

47 CFR 32.2441 - Conduit systems.  

Science.gov (United States)

...CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2441 Conduit systems. (a) This account shall include the original cost of conduit,...

2010-10-01

20

Joining insulated elongate conduit members  

Energy Technology Data Exchange (ETDEWEB)

An insulated elongate conduit member is provided, along with an assembly and a method for joining insulated elongate conduit members. The invention is described with reference to joining of thermally insulated pipes suitable for use in a district heating or cooling system. The insulated member of this invention is arranged so that connection to the member or interconnection of 2 such members may be effected in a particularly convenient manner, without subsequently having to create a layer of insulation around the connection. In one aspect, a pipe is provided with thermal insulation in which, at an end of the pipe, there is an annular recess to allow access for connection. To make a connection, a recoverable connecting collar is positioned at least partially within the recess, and allowed to recover into gripping engagement with the exposed portion of the pipe. The recoverable connecting collar may comprise metallic and/or polymeric material, such as heat recoverable metals that exhibit the shape memory effect, or a conductive polymeric material which can be electrically heated to its recovery temperature. 4 figs.

Van Dijck, F.S.J.

1990-05-22

 
 
 
 
21

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

22

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

23

A conduit to amplify innate immunity.  

Science.gov (United States)

In this issue of Immunity, Py et al. (2013) report that upon bacterial infection, a fragment of the matrix protein cochlin is released from the conduits of B cell follicles to trigger protective cytokines in the periphery. PMID:23706666

Moussion, Christine; Sixt, Michael

2013-05-23

24

The interior coating of rectangular conduit structures  

International Nuclear Information System (INIS)

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

25

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

Energy Technology Data Exchange (ETDEWEB)

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

Greiner, L.

1977-01-01

26

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

Directory of Open Access Journals (Sweden)

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

Sano,Shunji

1989-06-01

27

Nerve conduits for peripheral nerve surgery.  

Science.gov (United States)

Autologous nerve grafts are the current criterion standard for repair of peripheral nerve injuries when the transected nerve ends are not amenable to primary end-to-end tensionless neurorrhaphy. However, donor-site morbidities such as neuroma formation and permanent loss of function have led to tremendous interest in developing an alternative to this technique. Artificial nerve conduits have therefore emerged as an alternative to autologous nerve grafting for the repair of short peripheral nerve defects of less than 30 mm; however, they do not yet surpass autologous nerve grafts clinically. A thorough understanding of the complex biological reactions that take place during peripheral nerve regeneration will allow researchers to develop a nerve conduit with physical and biological properties similar to those of an autologous nerve graft that supports regeneration over long nerve gaps and in large-diameter nerves. In this article, the authors assess the currently available nerve conduits, summarize research in the field of developing these conduits, and establish areas within this field in which further research would prove most beneficial. PMID:24867724

Pabari, Amit; Lloyd-Hughes, Hawys; Seifalian, Alexander M; Mosahebi, Ash

2014-06-01

28

Extreme loads seismic testing of conduit systems  

International Nuclear Information System (INIS)

Rigid steel conduit (thin-wall tubes with threaded connections) containing electrical cabling are a common feature in nuclear power plants. Conduit systems are in many cases classified in U.S.A. practice as Seismic Category I structures. this paper summarizes results and others aspects of a dynamic test program conducted to investigate conduit systems seismic performance under three-axis excitation for designs representative at a nuclear power plant sited near Ft. Worth, Texas (a moderate seismic zone), with a Safe Shutdown Earthquake (SSE) of 0.12 g. Test specimens where subjected to postulated seismic events, including excitation well in excess of Safe Shutdown Earthquake events typical for U.S.A. nuclear power stations. A total of 18 conduit systems of 9-meter nominal lengths were shake table mounted and subjected to a variety of tests. None of the specimens suffered loss of load capacity when subjected to a site-enveloping Safe Shutdown Earthquake (SSE). Clamp/attachment hardware failures only began to occur when earthquake input motion was scaled upward to minimum values of 2.3-4.6 times site enveloping SSE response spectra. Tensile and/or shear failure of clamp attachment bolts or studs was the failure mode in all case in which failure was induced. (author)

29

Biochemical engineering nerve conduits using peptide amphiphiles.  

Science.gov (United States)

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. These include synthetic and artificial materials, which can be manufactured into nerve conduits using techniques inspired by nanotechnology. Recent evidence indicates that peptide amphiphiles (PAs) are promising candidates for use as materials for bioengineering nerve conduits. PAs are biocompatible and biodegradable protein-based nanomaterials, capable of self-assembly in aqueous solutions. Their self-assembly system, coupled with their intrinsic capacity for carrying bioactive epitopes for tissue regeneration, form particularly novel attributes for biochemically-engineered materials. Furthermore, PAs can function as biomimetic materials and advanced drug delivery platforms for sustained and controlled release of a plethora of therapeutic agents. Here we review the realm of nerve conduit tissue engineering and the potential for PAs as viable materials in this exciting and rapidly advancing field. PMID:22910143

Tan, Aaron; Rajadas, Jayakumar; Seifalian, Alexander M

2012-11-10

30

Dispersive hydrodynamics in viscous fluid conduits  

Science.gov (United States)

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

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

2013-08-01

31

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...2010-04-01 false Conduit financing arrangements. 1.881-3... § 1.881-3 Conduit financing arrangements. (a) General...or otherwise. (ii ) Restrictions on payment. The fact...whose participation in the financing arrangement may be...

2010-04-01

32

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

International Nuclear Information System (INIS)

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

33

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

Scientific Electronic Library Online (English)

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

Miguel, Aguirre.

2009-06-01

34

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

35

Secure E-Link For Jostle Conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Meenu Sahni

2011-01-01

36

Secure E-Link For Jostle Conduit  

Directory of Open Access Journals (Sweden)

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

Meenu Sahni

2011-01-01

37

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

38

Assessment of conduit artery vasomotion using photoplethysmography  

Science.gov (United States)

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

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

2013-11-01

39

Petrology of Conduit Lava at Unzen Volcano; Result of Unzen Scientific Drilling Project  

Science.gov (United States)

Lava samples were recovered from the conduit of the 1991-1995 eruption during the scientific drilling project in summer of 2004. Lava from the 1975-1997 m-depth conduit is most fresh among conduit samples and was nested in the hottest zone. The chemical composition including Sr isotopic ratio is very close to the 1991-1995 dome lava. The conduit lava is porphyritic dacite with phenocrysts of plagicolase, bioite and hornblende, though it is altered hydrothermally, such that hornblende was replaced by chlorite, carbonate and rutile, contrasting to freshness of biotite. The groundmass is composed of devitrified glass even in the chilled margins and contains small crystals of pyrite. As 3 wt % of water can be involved in the melt at the depth of 1.3 km where the conduit sample was recovered (about 40 MPa), about half of the initial water (6 wt %) should have been lost until when the magma reached this level. However, bubbles and microlites whose crystallization is induced by degassing are very scarce, compared in the groundmass of the dome lavas. Scarce amounts of microlites and bubbles indicate that degassing-induced crystallization was least in the ascending magma in this level, probably due to slow ascending (low cooling rate), and that bubbles could be escaped smoothly from the fluidal melt. As permeability of the country rocks is very low based on the logging data of the drilling, it is likely that magmatic volatiles should have escaped upward through cracks formed by ascending magma itself. Bubbles in the magma might have migrated into the tip of dyke magma where vapor-dominated tip was pressurized to form cracks. Crystallization of most of microlites commonly found in the dome lava had occurred in the shallower depth due to faster degassing (effective cooling rate).

Nakada, S.; Yoshimoto, M.; Shimano, T.; Kurokawa, M.; Nakai, S.; Sugimoto, T.; Hoshizumi, H.; Oguri, K.; Noguchi, S.; Goto, Y.

2004-12-01

40

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

Science.gov (United States)

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

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

2007-01-01

 
 
 
 
41

Evolution of Hydraulic Roughness During Early Stages of Conduit Growth: Effects on Conduit Enlargement Rates  

Science.gov (United States)

Hydraulic roughness exerts an important but poorly constrained control on the hydraulic capacity and enlargement rates of subglacial conduits. In an ideal, inviscid fluid, energy and mass are conserved along a flow line and the sum of the velocity, pressure and elevation heads equals the potential energy of the system, as described by the Bernoulli Equation. In real fluid flows, however, some of this energy is dissipated as heat due to friction and turbulence, resulting in a total head that is lower than predicted by the Bernoulli Equation. This departure from ideal is termed head loss, which is accounted for in simple hydrological models, such as the Manning or Darcy Weisbach equations, through the use of a roughness coefficient (n -s m1/3) or a friction factor (f - dimensionless), respectively. Both f and n relate hydraulic roughness to a relative roughness, or the ratio of the height that projections extend from the floor or wall of a conduit to the conduit hydraulic diameter. Such relationships, however, are empirically derived and only valid for relative roughness values that are 5% likely occur in subglacial conduits, particularly during early stages of conduit enlargement, which may limit ability to use relative roughness to calculate values of n or f. Understanding changes in roughness in the early stages of conduit enlargement is crucial for accurate modeling of glacier hydrological systems because nearly all glacier hydrological models rely on a hydraulic roughness parameterization to drive conduit melting. To address this knowledge gap, we calculated hydraulic roughness values from dye traces conducted at Rieperbreen, in Svalbard, Norway. Because conduit area and hydraulic gradients were constrained by direct mapping, and average flow velocities were obtained from dye traces, we were able to calculate f and n for each trace. Values of f and n declined from 75.01 and 0.68 s m1/3, respectively, to 0.97 and 0.04 s m1/3 over the melt season. Values of f and n calculated from dye tracing data exceeded values of f and n calculated solely from direct measurements of relative roughness by several orders of magnitude. Despite these discrepancies, values of f and n that were calculated from dye tracing data were highly correlated to measured relative roughness values using a power law, suggesting that new relationships may be developed for glacier hydrological systems. When we paramaterized a simple conduit enlargement model using our newly-discovered relationship between f, n and relative roughness, we found that the timescale required for conduits to grow from 0.5 m in diameter to a diameter where relative roughness was <5% was 4-9 times longer than enlargement times obtained using roughness parameterization schemes commonly used in glacier hydrological models.

Gulley, J. D.; Spellman, P.; Covington, M. D.; Martin, J. B.; Benn, D.; Catania, G. A.

2012-12-01

42

Parastomal Hernia as a Risk Factor for Ileal Conduit Fistulae  

Directory of Open Access Journals (Sweden)

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

Thomas A. A Skinner

2011-07-01

43

Superficial femoral-popliteal vein as a conduit for brachiocephalic arterial reconstructions.  

Science.gov (United States)

Revascularization of brachiocephalic arteries with prosthetic graft offers excellent patency for most reconstructions. For complex brachiocephalic reconstructions, such as redo operations or reconstructions for infection, autogenous conduit may be preferable. Occasionally saphenous vein is inadequate or absent. The purpose of this study was to evaluate the indications and intermediate-term outcomes of superficial femoral-popliteal vein (SFPV) as an alternative conduit for brachiocephalic reconstructions. Over a 6-year period, 71 patients underwent carotid, subclavian, or axillary artery bypass. In 18 (25%) of these reconstruction SFPV was used as the conduit. Ten bypasses (55%) were redo operations. Three bypasses (17%) were performed after failed prosthetic grafts. Three grafts (17%) were required in infected patients. Indications for the use of SFPV included inadequate saphenous vein (n = 13), infection (n = 3), and failed prosthetic bypass (n = 3). Thirty-day mortality was 5.5%. The neurologic event rate was 5.5%. During a mean follow-up of 26 +/- 5 months, there were no graft thromboses or graft infections. Revision-free primary patency was 92% at 48 months. Assisted primary patency was 100%. These data suggest that SFPV is a safe, durable conduit for brachiocephalic reconstructions. SFPV yielded excellent results for a disadvantaged patient population. PMID:11904799

Modrall, J Gregory; Joiner, Donald R; Seidel, Scott A; Jackson, Mark R; Valentine, R James; Clagett, G Patrick

2002-01-01

44

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.

1972-01-01

45

Nanofibrous nerve conduit-enhanced peripheral nerve regeneration.  

Science.gov (United States)

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

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

2014-05-01

46

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 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

47

Effects of PVC conduits on sampling results of aerosol  

International Nuclear Information System (INIS)

This paper presents the effects of PVC conduits on sampling results of aerosol. The MMAD of aerosol experimentally adopted is 7.1 ?m. Through 15 m PVC conduits with diameter of 30 mm and 50 mm, the concentration of aerosol decreased to 14.5% and 6.4% of the primary concentration respectively under laminar flow conditions, and to 21.3% and 15.4% under turbulence conditions. The aerosol size also changed, the mass fraction of particles of 4 ?m increases about 5 times. The method for determining the fraction of wall deposition is briefly introduced. The selection of sampling conduits and relevant aspects in application are also discussed

48

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

Science.gov (United States)

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

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

2014-03-01

49

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

50

Modeling the evolution of karstic conduits along inception horizons  

Science.gov (United States)

The evolution of karst systems is driven by a feedback mechanism between carbonate dissolution and flow processes. In general numerical simulations of this mechanism start with an initial configuration of inception horizons, such as fractures and bedding planes, which are horizons most susceptible to karstification. Since models for karst evolution have mainly focused on understanding the underlying physical and chemical processes, the initial configuration is usually based on very simple geometries. Consequently, simulation results usually do not resemble a realistic network of karstic voids. Our objective is to simulate more realistic karstic networks by starting with more complex and realistic configurations of inception horizons. The modeling approach permits a statistic control on the initial configuration and results in a simulated network of circular conduits. In a first step we define the bedding planes and use an existing stochastic model to generate sets of fractures. Subsequently, triangulations of these two-dimensional objects are used to define an initial geometry of the conduit network. Namely, every edge within these triangulations represents part of the initial conduit network. The initial diameter of the conduits is based on a probability distribution which is related to the properties of the inception horizons. The resulting conduit network, representing an assumed initial state of the inception horizons, is coupled with a surrounding three-dimensional matrix domain. Flow can thus be simulated using a model for coupled conduit-matrix flow, provided that the model can handle complex conduit networks. The flow model is coupled with a dissolution model based on classical methodologies which permits to increase the diameters of the conduits. With our model we test common hypotheses about cave development. We are particularly interested in how caves form in eogenetic karst systems which are characterized by a relatively permeable rock matrix.

De Rooij, R.; Graham, W. D.

2013-12-01

51

Current understanding of phase separation mechanisms in branching conduits  

International Nuclear Information System (INIS)

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

52

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

53

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

Science.gov (United States)

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

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

2009-07-14

54

Body Image Following Radical Cystectomy and Ileal Neobladder or Conduit in Korean Patients  

Science.gov (United States)

Purpose The aim of this study was to compare the body images of patients who underwent radical cystectomy with an orthotopic ileal neobladder or an ileal conduit. Materials and Methods A total of 114 adult patients who underwent radical cystectomy between March 2006 and December 2012 at a single institution, Ewha Womans University Mokdong Hospital in Korea, were evaluated in this retrospective chart-review study. Forty-two patients (29 orthotopic ileal neobladder and 13 ileal conduit) who completed questionnaires were included in the final analysis; the remaining patients were excluded. The patients were assessed with two questionnaires: the Korean version of the Body Image Scale (K-BIS) and the self-designed questionnaire. Results The results did not differ significantly by age at surgery, time from surgery to survey, pathologic stage, grade, histologic subtype, education, residency, or Eastern Cooperative Oncology Group performance status, but did differ significantly by age at survey and sex. The mean summary score for K-BIS showed significant differences between the two groups (p=0.001). We found that patients who underwent an orthotopic ileal neobladder had a significantly better body image. The self-designed questionnaire score was not significantly different between the two groups (p=0.572). Conclusions In our retrospective analysis, patients who underwent orthotopic ileal neobladder had a superior body image compared with those who underwent an ileal conduit. PMID:24648869

Shim, Bosun; Kim, Kwang Hyun; Yoon, Hyunsuk; Park, Young Yo

2014-01-01

55

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

56

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)

57

Thermomechanical milling of accessory lithics in volcanic conduits  

Science.gov (United States)

Accessory lithic clasts recovered from pyroclastic deposits commonly result from the failure of conduit wall rocks, and represent an underutilized resource for constraining conduit processes during explosive volcanic eruptions. The morphological features of lithic clasts provide distinctive 'textural fingerprints' of processes that have reshaped them during transport in the conduit. Here, we present the first study focused on accessory lithic clast morphology and show how the shapes and surfaces of these accessory pyroclasts can inform on conduit processes. We use two main types of accessory lithic clasts from pyroclastic fallout deposits of the 2360 B.P. subplinian eruption of Mount Meager, British Columbia, as a case study: (i) rough and subangular dacite clasts, and (ii) variably rounded and smoothed monzogranite clasts. The quantitative morphological data collected on these lithics include: mass, volume, density, 2-D image analysis of convexity (C), and 3-D laser scans for sphericity (?) and smoothness (S). Shaping and comminution (i.e. milling) of clasts within the conduit are ascribed to three processes: (1) disruptive fragmentation due to high-energy impacts between clasts or between clasts and conduit walls, (2) ash-blasting of clasts suspended within the volcanic flux, and (3) thermal effects. We use a simplified conduit eruption model to predict ash-blasting velocities and lithic residence times as a function of clast size and source depth, thereby constraining the lithic milling processes. The extent of shape and surface modification (i.e. rounding and honing) is directly proportional to clast residence times within the conduit prior to evacuation. We postulate that the shallow-seated dacite clasts remain subangular and rough due to short (<2 min) residence times, whereas monzogranite clasts are much more rounded and smoothed due to deeper source depths and consequently longer residence times (up to ˜1 h). Larger monzogranite clasts are smoother than smaller clasts due to longer residence times and to greater differential velocities within the ash-laden jet. Lastly, our model residence times and mass loss estimates for rounded clasts are used to estimate minimum attrition rates due to volcanic ash-blasting within the conduit (e.g., 12 cm3?s-1 for 25 cm clasts, sourced at 2500 m depth).

Campbell, Michelle E.; Russell, James K.; Porritt, Lucy A.

2013-09-01

58

Aeration efficiency of free-surface conduit flow systems.  

Science.gov (United States)

Dissolved oxygen is a measure of the quantity of oxygen present in water and is one of the best indicators of the health of a water ecosystem. Dissolved oxygen levels in water can be increased by creating turbulent conditions where fine air bubbles are carried into the bulk of the flow. This is achieved by hydraulic structures. A free-surface conduit is a particular instance of this. In the present work, a series of experiments were conducted to investigate the aeration efficiency of free-surface conduit flow systems. The results indicate that free-surface conduit flow systems are very effective for oxygen transfer. At Froude numbers greater than 15, almost full oxygen transfer up to the saturation value was reached. Moreover, from experimental data, a regression equation was obtained with a very high correlation coefficient, showing the effect of various parameters on the aeration efficiency. PMID:20183998

Unsal, M; Baylar, A; Tugal, M; Ozkan, F

2009-12-14

59

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

60

Modeling Reactive Transport in Coupled Groundwater-Conduit Systems  

Science.gov (United States)

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

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

2002-05-01

 
 
 
 
61

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

Science.gov (United States)

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

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

2009-08-26

62

Usability of photoplethysmography method in estimation of conduit artery stiffness  

Science.gov (United States)

Three channel photoplethysmography (PPG) signal waveform studies of leg conduit arteries during a provocative occlusion test were performed. PPG waveform second derivative amplitude ratio and arterial pulse wave velocity values showed significant correlations with ultrasound (US) reference method of local and regional arterial stiffness (AS), showing the ability to use PPG for AS change quantitative assessment.

Grabovskis, A.; Marcinkevics, Z.; Lukstina, Z.; Majauska, M.; Aivars, J.; Lusa, V.; Kalinina, A.

2011-07-01

63

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

64

Evaluation of the MODFLOW-2005 Conduit Flow Process.  

Science.gov (United States)

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

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

2010-01-01

65

Recurrent transitional cell carcinoma in an ileal conduit.  

Science.gov (United States)

A patient with recurrent transitional cell carcinoma involving an ileal conduit is reported. This case is unusual for the following reasons: the malignancy was located in an area where there was no transitional epithelium; a "napkin ring" deformity was present; there was a 6-year interval between the initial cystectomy and the recurrence of the malignancy. PMID:553366

Rubin, B E; Rodriguez, E; Mangasarian, R; Cummings, J; Kwart, A

1979-01-01

66

Combined physical and chemical nonequilibrium transport model for solution conduits  

Science.gov (United States)

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

Field, Malcolm S.; Leij, Feike J.

2014-02-01

67

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

68

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

Science.gov (United States)

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

2013-10-09

69

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

Science.gov (United States)

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

2013-08-30

70

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

Science.gov (United States)

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

2013-10-09

71

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

Science.gov (United States)

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

2013-09-16

72

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

Science.gov (United States)

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

2013-10-18

73

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

Science.gov (United States)

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

2013-11-21

74

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

Science.gov (United States)

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

2013-10-23

75

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

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

Bubble Rise and Break-Up in Volcanic Conduits  

Science.gov (United States)

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

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

2013-12-01

78

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

79

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

CERN Document Server

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.

Joo, H

1999-01-01

80

Pyroclastic conduits of the late Cenozoic collapse calderas from Japan  

Science.gov (United States)

There are many late Cenozoic calderas in Japan. Many of the late Cenozoic calderas are the large-scale collapse calderas of the piston-cylinder type, and consist of collapsed volcanic basin surrounded by arcuate ring faults or array of vents and the surrounding pyroclastic flow deposits. Yoshida (1984) reported intrusive breccia dikes between the subsided block and wall rocks of the Ishizuchi cauldron, SW Japan. The intrusive breccias consist of tuff and tuff breccias containing many kinds of rock fragments. Contacts with surrounding rocks are sharp. Some breccia dikes along the marginal ring fracture zone of the cauldron, which are composed of welded pyroclastic rocks, probably fill vents from which the surrounding pyroclastic flow deposits were discharged. The matrix of the intrusive breccia is welded ash and/or clastic powder. Fragments vary in size from millimeters to several meters. Local continuity of structures from one fragment to another indicates that the brecciation was not a consequence of explosive action; these are interpreted as intrusive breccias produced by fluidization processes, probably associated with pyroclastic explosions. These breccias were intruded upward to their present positions as part of a fluidization system. Intrusive breccia and tuff within the ring fault complex contain a eutaxitic foliation oriented nearly parallel to contacts. This feature is thought to result from inwardly directed pressures exerted by the dike walls during caldera collapse following eruption of the pyroclastic flows. The eutaxitic foliation indicates that the intrusive breccia and tuff were emplaced as a fluidized system of gas, solid particles, and probably liquid droplets. Mt. Taiheizan is located 20km northeast of Akita, NE Japan. There is the late Miocene to early Pliocene Nibetsu cauldron on Mt. Taiheizan. Recent study revealed the details of a contemporary arcute pyroclastic conduit consisting of felsic tuff. This Hirasawa felsic tuff dyke is about 5 km long and 100m wide, and it has four facies - massive facies, lithic-rich facies, fluidized network facies, and laminated marginal facies. Just outside of this arcuate pyroclastic conduit, a pyroclastic flow deposit estimated as an outflow from Hirasawa felsic tuff dyke, was found. It has the same mineral compositions and chemical compositions of glass. These tuff dyke and its outflow can correlated to the submarine pyroclastic mass flow facies. The Hirasawa arcuate pyroclastic conduit with the eruption of pyroclastic flow is considered to have been formed at the earliest Pliocene, and at this time, uplift of Mt. Taiheizan occurred together with the caldera resurgence of Nibetsu cauldron. Therefore, the formation of Hirasawa arcuate pyroclastic conduit is thought to have a close relationship with the resurgence of Nibetsu cauldron. The Motoisago caldera and the Takebayashi caldera are distributed near Sendai, NE Japan (Takahashi et al., 2006). The pyroclasitc conduits of these calderas are presumed at their margin between basements and horizontally stratified caldera-filling tuff beds. The conduits are not welded, but soft and vertically laminated with slumping structures caused by subsidence along the caldera wall. Almond (1971) has classified the pyroclastic conduits into forceful (diatreme) type and permissive injections associated with caldera-collapse. He showed no example of the permissive injections at low temperature. The pyroclastic conduits from these calderas near Sendai might be good examples of this type.

Yoshida, T.; Iwahashi, A.; Takahashi, T.; Nagahashi, Y.

2006-12-01

 
 
 
 
81

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

82

Structure of a bacterial cell surface decaheme electron conduit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or...

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

2011-01-01

83

Bubble suspension rheology and implications for conduit flow.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bubbles are ubiquitous in magma during eruption and influence the rheology of the suspension. Despite this, bubble-suspension rheology is routinely ignored in conduit-flow and eruption models, potentially impairing accuracy and resulting in the loss of important phenomenological richness. The omission is due, in part, to a historical confusion in the literature concerning the effect of bubbles on the rheology of a liquid. This confusion has now been largely resolved and recently published stu...

Llewellin, E. W.; Manga, M.

2005-01-01

85

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

86

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

87

Economical recovery of hydrocarbon vapors  

Energy Technology Data Exchange (ETDEWEB)

Up to 90% of the escaping hydrocarbon vapors can be safely and efficiently recovered by means of a new system whose functions are based on the principles of refrigeration and low pressure. These vapors, which are quite valuable when recovered, are generated during the loading of tank cars, tank trucks, and by natural respiration of the storage tanks. Such a system of gasoline vapor recovery was developed by the Southwest Industries (SWI), a subsidiary of Ingersoll Rand Co. THe SWI Unit uses a method of absorption at low temperature, in the place of high pressure absorption, which requires compression of the vapors. Additional benefits for low temperature absorption are listed. This ability to recover these vapors is good news to refiners and petrochemical plant operators, adding considerable revenue to their operations at a reasonable cost and payout time (cost varies from $70,000 to $200,000 for a complete plant, the total cost depending on the number of tanks served).

1972-10-01

88

High bandwidth vapor density diagnostic system  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a high bandwidth atomic vapor density diagnostic system. It comprises: means for generating a high bandwidth laser beam, means for amplitude modulating the high bandwidth laser beam, means for propagating the modulated laser beam through an atomic vapor during one or more photoionization events, means for detecting the propagated laser beam to form a detected signal, and lock-in amplifier means for removing pickup noise from the detected signal.

Globig, M.A.; Story, T.W.

1992-10-06

89

Aneurysmal dilatation of the Contegra bovine jugular vein conduit after reconstruction of the right ventricular outflow tract.  

Science.gov (United States)

An aneurysm of a 14-mm Contegra bovine conduit 5 years after a total repair of tetralogy of Fallot was confirmed by echocardiography, angiography, and magnetic resonance tomography. The conduit was replaced. Histologic examination of the explanted conduit revealed an acellular homogenous material with occasional elastic fibers, fragile, diffuse and complex collagenization throughout the conduit and mild foreign body reaction. Pannus formed over the top of all commissures and on the conduit wall, with extensive mineralization. Close follow-up is seen as mandatory for early detection of the bovine vein conduit aneurysm, particularly in patients in whom small-sized conduits are implanted. PMID:17258016

Delmo-Walter, Eva Maria; Alexi-Meskishvili, Vladimir; Abdul-Khaliq, Hashim; Meyer, Rudolf; Hetzer, Roland

2007-02-01

90

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)

91

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

Science.gov (United States)

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

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

2012-12-01

92

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

93

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.

94

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.

95

A meter used to measure losses due to scattering in fiber-optic conduits  

Energy Technology Data Exchange (ETDEWEB)

A meter used to measure optical losses due to scattering in fiber optic conduits is discussed. These losses can be measured only in fiber-optic conduits that do not have a protective or any other kind of casing. These measurements are conducted by drawing the conduit through a special photodetector device used for scattered radiation. This radiation is detected, amplified and filtered, after which the signals that carry the data on the scattering level pass into a two-channel automatic recorder.

Ermokhin, M.I.; Cherenkov, G.A.; Khasin, Y.S.; Shepeleva, T.V.

1980-01-01

96

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most 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 ac...

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

2013-01-01

97

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

Science.gov (United States)

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

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

2008-01-01

98

Hydraulic and geological factors influencing conduit flow depth  

Directory of Open Access Journals (Sweden)

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

Worthington,S.R.H.

2005-01-01

99

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

100

40 CFR 52.787 - Gasoline transfer vapor control.  

Science.gov (United States)

... 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.787 Section...IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer vapor control. (a) Gasoline means any petroleum distillate having...

2010-07-01

 
 
 
 
101

40 CFR 52.255 - Gasoline transfer vapor control.  

Science.gov (United States)

... 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.255 Section...IMPLEMENTATION PLANS California § 52.255 Gasoline transfer vapor control. (a) “Gasoline” means any petroleum distillate...

2010-07-01

102

Vaporization of perfluorocarbon droplets using optical irradiation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

103

Results of right atrial to right ventricular and right atrial to pulmonary artery conduits for complex congenital heart disease.  

Science.gov (United States)

The Fontan procedure was initially proposed for tricuspid atresia (TA). We describe our experience with modifications of this operation and its application to previously uncorrectable congenital lesions. From 1975 to 1979, 26 patients have undergone a Fontan-like procedure, at a mean age of 14 years (range: 3 months to 23 years). Nineteen patients had TA, one patient had mitral atresia, four patients had a univentricular heart, one patient had a "criss-cross" heart, and one patient had pulmonary atresia. Previous procedures included eight Glenn shunts, 18 systemic to pulmonary artery (PA) shunts, two PA bands, and two atrial septectomies. Thirteen patients underwent right atrial (RA) to PA connections, with a valved conduit in nine patients and without in four. Two patients had simultaneous Glenn shunts. Thirteen had RA to right ventricular (RV) conduits, with a valve in 12 patients and without in one. There were five early deaths (<30 days, 19%) and no significant difference between the RA to PA connection (four deaths of 13) versus the RA to RV connection (one death of 13). The mortality rate was higher in patients undergoing RA to PA connection without valved conduit (one death of nine with a valve, three deaths of four without, p < 0.05), while the Glenn shunt did not affect mortality (one death of seven with, three of six without, p < 0.1). There were no late deaths (mean follow-up: 24 months). Seven patients underwent recatheterization with a mean RA pressure of 14 mmHg (range: 9--25 mmHg). Thus, the "Fontan" procedure can be done with an acceptably low mortality with good functional results, both for TA and other complex lesions. PMID:7416832

Laks, H; Williams, W G; Hellenbrand, W E; Freedom, R M; Talner, N S; Rowe, R D; Trusler, G A

1980-09-01

104

Viscous Fluid Conduits as a Prototypical Nonlinear Dispersive Wave Platform  

Science.gov (United States)

This thesis is devoted to the comprehensive characterization of slowly modulated, nonlinear waves in dispersive media for physically-relevant systems using a threefold approach: analytical, long-time asymptotics, careful numerical simulations, and quantitative laboratory experiments. In particular, we use this interdisciplinary approach to establish a two-fluid, interfacial fluid flow setting known as viscous fluid conduits as an ideal platform for the experimental study of truly one dimensional, unidirectional solitary waves and dispersively regularized shock waves (DSWs). Starting from the full set of fluid equations for mass and linear momentum conservation, we use a multiple-scales, perturbation approach to derive a scalar, nonlinear, dispersive wave equation for the leading order interfacial dynamics of the system. Using a generalized form of the approximate model equation, we use numerical simulations and an analytical, nonlinear wave averaging technique, Whitham-El modulation theory, to derive the key physical features of interacting large amplitude solitary waves and DSWs. We then present the results of quantitative, experimental investigations into large amplitude solitary wave interactions and DSWs. Overtaking interactions of large amplitude solitary waves are shown to exhibit nearly elastic collisions and universal interaction geometries according to the Lax categories for KdV solitons, and to be in excellent agreement with the dynamics described by the approximate asymptotic model. The dispersive shock wave experiments presented here represent the most extensive comparison to date between theory and data of the key wavetrain parameters predicted by modulation theory. We observe strong agreement. Based on the work in this thesis, viscous fluid conduits provide a well-understood, controlled, table-top environment in which to study universal properties of dispersive hydrodynamics. Motivated by the study of wave propagation in the conduit system, we identify four new admissibility criteria required for proper application of the Whitham-El DSW closure method for a general class of scalar dispersive hydrodynamic equations. Further, we explore regularization distinguishing characteristics of dissipative versus dispersive smoothing in a bidirectional system, Fermi gas at unitarity, in which the appropriate physical mechanism is unclear. It is shown that key differences in the resolution of nonlinear wave breaking allow one to design regularization determining experiments.

Lowman, Nicholas K.

105

Development and manufacturing of superconducting cable in conduit conductors  

Science.gov (United States)

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

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

106

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

Science.gov (United States)

The primary purpose of water aeration is to increase the oxygen saturation of the water. This can be achieved by using hydraulic structures because of substantial air bubble entrainment at these structures. Closed conduit aeration is a particular instance of this. While there has been a great deal of research on air-demand ratio within closed conduit, very little research has specifically addressed aeration efficiency of closed conduit. In the present work an experimental study was conducted to investigate the aeration efficiency of high-head gated circular conduits. Results showed that high-head gated circular conduits were effective for oxygen transfer. The effects of Froude number and ratio of the water cross-sectional flow area to the conduit cross-sectional area on aeration efficiency were particularly significant, whereas the effect of conduit length was only moderate. Further, a design formula for the aeration efficiency was presented relating the aeration efficiency to ratio of water cross-sectional flow area to conduit cross-sectional area and Froude number. The obtained results will be useful in future modeling processes and aid the practicing engineer in predicting aeration efficiency for design purposes. PMID:24647194

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

2014-01-01

107

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

Science.gov (United States)

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

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

2009-01-01

108

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

Science.gov (United States)

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

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

2014-10-01

109

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

Directory of Open Access Journals (Sweden)

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

White,W.B.

2005-01-01

110

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

111

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

Science.gov (United States)

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

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

2003-01-01

112

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

113

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

114

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.

115

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

Science.gov (United States)

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

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

2013-01-01

116

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

117

Fibrin matrix for suspension of regenerative cells in an artificial nerve conduit.  

Science.gov (United States)

Peripheral nerve injury presents with specific problems of neuronal reconstructions, and from a clinical viewpoint a tissue engineering approach would facilitate the process of repair and regeneration. We have previously used artificial nerve conduits made from bioresorbable poly-3-hydroxybutyrate (PHB) in order to refine the ways in which peripheral nerves are repaired and reconnected to the target muscles and skin. The addition of Schwann cells (SC) or differentiated mesenchymal stem cells (dMSC) to the conduits enhances regeneration. In this study, we have used a matrix based on fibrin (Tisseel) to fill optimally the nerve-conduits with cells. In vitro analysis showed that both SC and MSC adhered significantly better to PHB in the presence of fibrin and cells continued to maintain their differentiated state. Cells were more optimally distributed throughout the conduit when seeded in fibrin than by delivery in growth medium alone. Transplantation of the nerve conduits in vivo showed that cells in combination with fibrin matrix significantly increased nerve regeneration distance (using PGP9.5 and S100 distal and proximal immunohistochemistry) when compared with empty PHB conduits. This study shows the beneficial combinatory effect of an optimised matrix, cells and conduit material as a step towards bridging nerve gaps which should ultimately lead to improved functional recovery following nerve injury. PMID:18218346

Kalbermatten, D F; Kingham, P J; Mahay, D; Mantovani, C; Pettersson, J; Raffoul, W; Balcin, H; Pierer, G; Terenghi, G

2008-06-01

118

The separation of hydrocarbons from waste vapor streams  

International Nuclear Information System (INIS)

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

119

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

Directory of Open Access Journals (Sweden)

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

T. Reimann

2013-04-01

120

Forgotten DJ Stent with a Large Calculus at Its Distal End in an Ileal Conduit Diversion  

Science.gov (United States)

Calculus formation in an ileal conduit following cystectomy is a known complication. Encrustation and formation of calculus may also occur over a DJ stent retained for a long period; but this is never reported in patients with conduit diversion because of close surveillance of these patients. Here we report first case of a large calculus encrusted over a forgotten DJ stent within an ileal conduit in a man who had undergone urinary diversion following radical cystectomy for carcinoma urinary bladder 8 years earlier. PMID:25215257

Puri, Anurag; Priyadarshi, Vinod; Raizada, Nivedita; Pal, Dilip Kumar

2014-01-01

 
 
 
 
121

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

122

Study of Trailing Conduits in High Bond Number Metal-Silicate Plumes during Core Formation  

Science.gov (United States)

Meteorite samples and isotopic studies indicate that segregation of the Earth's metallic core from silicates happened within 30 Myr of the formation of the Solar System. Core formation in other terrestrial planets is similarly rapid during the formation of the Solar System. Previous geodynamic studies hypothesized that violent impacts provided substantial energy for partial or complete melting of impactors and surrounding materials, leading to the formation of a magma ocean or reservoir. Metal ejecta of the cores of differentiated planetesimals may have formed metal drops, descended through the magma ocean and collected into metal ponds at the base of the magma ocean. Over time, the heavy liquid metallic ponds become unstable and descend through the primitive mantle, either following cracks and fractures or larger downwelling events involved in convective structures such as Rayleigh-Taylor instabilities or large diapirs. In this research, we perform experiments to study the case of large diapirs which go unstable as Rayleigh-Taylor instabilities. Once a metal pond descends through the primitive mantle, it creates a conduit behind it which fills with low density magma ocean material. Using fluid laboratory experiments, we observe the onset time of the high Bond number metal-silicate plume and its size and shape during descent. We identify three regimes during metal-silicate plume descent, 1) Conduit growth and the descent of the metal plume and conduit fluid; 2) Flow reversal ascent of conduit fluid, and conduit collapse; 3) Slow long-term collapse of remaining conduit dominated by diffusion processes. Theoretical predictions are consistent with fluid measurements for each regime and indicate these regimes may exist in the Earth with predictable time frames. We find the time for metal plume descent in Regime 1 is 8 Myr (radius (R) = 500 km) to reach the core-mantle boundary. The time for the conduit to constrict in Regime 2 is 6.5 Myr (R = 500 km). The time scale for final collapse of the residual small conduit radius is very long in Regime 3 at 3.3 x 108 Byr considering the diffusion time for silicate material to diffuse over a distance of 200 km (assuming diffusion coefficient of 10-17 m2/s for the bulk solid mantle). Thus, we suggest that Regime 3 where small conduits persist for long times following core formation may still be present in the Earth today. Conduit Evolution with 3 regimes: (1) Sinking of the metal drop; (2) Flow reversal and conduit constriction; (3) Slow long-term collapse of remaining conduit dominated by diffusion processes.

Nguyen, C. T.; Weeraratne, D. S.; Olson, P.

2010-12-01

123

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

124

A conduit dilation model of methane venting from lake sediments  

Science.gov (United States)

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

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

2011-01-01

125

Finite element modelling of cable-in-conduit conductors  

Science.gov (United States)

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

Bajas, Hugues; Durville, Damien; Devred, Arnaud

2012-05-01

126

Structure of a Bacterial Cell Surface Decaheme Electron Conduit  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-05-23

127

Calculation of electrohydrodynamic flow in a circular cylindrical conduit  

Energy Technology Data Exchange (ETDEWEB)

The electrohydrodynamic flow of a fluid in an `ion drag` configuration in a circular cylindrical conduit is governed by a non-linear second-order ordinary differential equation. The degree of non-linearity in this equation is determined by a nondimensional parameter {alpha} and the equation can be approximated by two different linear equations for very small or very large values of {alpha} respectively. Perturbation solutions of the fluid velocities for {alpha}<<1 and {alpha}>>1 are developed. A Gauss-Newton finite-difference solver combined with the continuation method and a Runge-Kutta shooting method are used to provide numerical results for the fluid velocity over a large range of values of {alpha}. Both numerical and analytical results are compared in order to establish the range of validity for the perturbation solutions. (orig.) [Deutsch] Die elektrohydrodynamische Stroemung in einer `ion-drag`-Konfiguration in einem kreiszylindrischen Rohr wird durch eine nichtlineare gewoehnliche Differentialgleichung 2. Ordnung beschrieben. Der Grad der Nichtlinearitaet dieser Gleichung wird durch einen dimensionslosen Parameter {alpha} bestimmt, und die Gleichung kann durch zwei verschiedene lineare Gleichungen fuer sehr kleine bzw. sehr grosse Werte von {alpha} approximiert werden. Die Stoerungsloesungen der Fluidgeschwindigkeiten fuer {alpha}<<1 und {alpha}>>1 werden hergeleitet. Ein Gauss-Newton Finite-Differenz-Loesungsverfahren, kombiniert mit der Fortsetzungsmethode und einem Runge-Kutta Shooting-Verfahren werden benutzt, um numerische Resultate fuer die Stroemungsgeschwindigkeit ueber einen grossen {alpha}-Bereich herzuleiten. Die numerischen und analytischen Resultate werden verglichen, um den Gueltigkeitsbereich der Stoerungsloesungen festzustellen. (orig.)

McKee, S.; Watson, R. [Dept. of Mathematics, Strathclyde Univ., Glasgow (United Kingdom); Cuminato, J.A. [ICMSC, Univ. of Sao Paulo (Brazil); Caldwell, J.; Chen, M.S. [City Univ. of Hong Kong (Hong Kong)

1997-12-31

128

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

129

Vapor spill pipe monitor  

Science.gov (United States)

The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote IR gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote IR sensor which measures the gas composition.

Bianchini, G. M.; McRae, T. G.

1983-06-01

130

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

131

Effect of multiwall carbon nanotube reinforcement on coaxially extruded cellular vascular conduits.  

Science.gov (United States)

Due to its abundant source, good biocompatibility, low price and mild crosslinking process, alginate is an ideal selection for tissue engineering applications. In this work, alginate vascular conduits were fabricated through a coaxial extrusion-based system. However, due to the inherent weak mechanical properties of alginate, the vascular conduits are not capable of biomimicking natural vascular system. In this paper, multiwall carbon nanotubes (MWCNT) were used to reinforce vascular conduits. Mechanical, dehydration, swelling and degradation tests were performed to understand influences of MWCNT reinforcement. The unique mechanical properties together with perfusion and diffusional capability are two important factors to mimic the nature. Thus, perfusion experiments were also conducted to explore the MWCNT reinforcement effect. In addition, cell viability and tissue histology were conducted to evaluate the biological performance of conduits both in short and long term for MWCNT reinforcement. PMID:24863208

Zhang, Yahui; Yu, Yin; Dolati, Farzaneh; Ozbolat, Ibrahim T

2014-06-01

132

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

Directory of Open Access Journals (Sweden)

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

Kozo Uto

2005-09-01

133

Human Immunodeficiency Virus type 1 Endocytic Trafficking Through Macrophage Bridging Conduits Facilitates Spread of Infection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Bridging conduits (BC) sustain communication and homeostasis between distant tethered cells. These are also exploited commonly for direct cell-to-cell transfer of microbial agents. Conduits efficiently spread infection, effectively, at speeds faster than fluid phase exchange while shielding the microbe against otherwise effective humoral immunity. Our laboratory has sought to uncover the mechanism(s) for these events for human immunodeficiency virus type one (HIV-1) infection. Indeed, in our ...

Kadiu, Irena; Gendelman, Howard E.

2011-01-01

134

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

135

Tapering of xylem conduits and hydraulic limitations in sycamore (Acer pseudoplatanus) trees.  

Science.gov (United States)

Vertical conduit tapering is proposed as an effective mechanism to almost eliminate the increase in hydraulic resistance with increased height. Despite this potential role, very little is known about its changes during ontogeny. Here, conduit tapering and stem morphology of young/small and old/tall individuals of Acer pseudoplatanus in the field, as well as 3-yr-old grafted trees from both age classes, were analysed. The distribution of hydraulic resistance along stems was also determined in a subsample of trees. Substantial conduit tapering was found in small trees (field-grown and grafted from both age classes), whereas values were lower in tall trees, indicating that tapering was a size-related, not an age-related process. Apical conduit diameters were larger in tall trees and were inversely correlated with the degree of tapering. Hydraulic resistance increased less than linearly with distance from the apex. Its scaling against distance was indistinguishable from that predicted from anatomical measurements. Conduit tapering was an effective but partial mechanism of compensation for the increase in hydraulic resistance with tree height. Size-related changes in tapering and in apical conduit diameters may be explained by the combined need to reduce the build-up of hydraulic resistance while minimizing the carbon costs of building vessel walls. PMID:18069964

Petit, Giai; Anfodillo, Tommaso; Mencuccini, Maurizio

2008-01-01

136

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

137

Liquid cryogenic vaporizer utilizing ambient air and a nonfired heat source  

International Nuclear Information System (INIS)

An apparatus is described for vaporizing a liquid cryogen comprising: a heat source; first means for extracting heat from the heat source; second means for extracting means from the ambient environment; third means for transferring heat from one of the first and second means to the liquid cryogen to partially vaporize the liquid cryogen; and separate fourth means for transferring heat from the heat source to the liquid cryogen to completely vaporize the partially vaporized liquid cryogen, whereby the liquid cryogen is completely vaporized at high flow rate in an economic manner

138

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

139

Mechanisms of englacial conduit formation and their implications for subglacial recharge  

Science.gov (United States)

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

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

2009-09-01

140

Characterizing aperture distributions in karst aquifers by simulating the evolution of solution conduits  

Science.gov (United States)

Karst aquifers develop where solutional enlargement of small interconnected openings such as fractures and bedding planes creates highly permeable conduits embedded in the much less permeable fissured porous rock. The hydrogeological characterization of these heterogeneous flow systems can be supported by simulating the evolution of solution conduits. In this work, both generic models representing hypothetical carbonate environments and site-related models referring to the gypsum karst settings of the Western Ukraine are used to examine how the hydrogeological environment determines the evolving aperture distributions. The generic models comprise regular networks of interconnected protoconduits with spatially uncorrelated lognormally distributed apertures of about one millimeter and less. For each model setting several realizations are performed and statistically analyzed. Different hydraulic boundary conditions are considered to account for the limited availability of flow inherent in any type of hydrogeological environment. Thus, the initial hydraulic gradient is reduced with ongoing conduit development such that the predefined maximum flow rate is not exceeded. If the maximum flow rate in the karst system is not strongly limited conduit development is found to be competitive and leads to stable bimodal aperture distributions; only a limited number of conduits continue to grow and the remaining apertures stay small. The number of large-sized conduits tends to decrease with increasing variance of the initial apertures and with decreasing maximum flow rate. However, strongly limited flow rates lead to more uniform aperture distributions. The results from the above-described generic scenarios agree with those from site-related models representing the multi-storey artesian settings of the gypsum karst terrain of the Western Ukraine (Rehrl et al., Water Resourc. Res. 44, W11425). In this type of setting, a soluble unit is sandwiched between less soluble formations and is supplied with chemically aggressive water from beneath. At the early stage, flow through the soluble unit is driven by a high vertical hydraulic gradient. Yet hydraulic gradients are diminished once a hydraulic connection between the soluble aquifers underlying and overlying the soluble unit is established due to the enlargement of solution conduits. At this late stage, the maximum flow rate is controlled by the regional boundary conditions and the permeability of the aquifers. If the permeability is sufficiently high, conduit development is found to be competitive, thus leading to bimodal aperture distributions. In a low-permeability formation, however, conduit development is found to be less selective due to the strong limitation of the maximum flow rate. Thus, multiple pathways develop and the frequency distribution of conduit apertures appears to be unimodal rather than bimodal.

Rehrl, C.; Hubinger, B.; Birk, S.

2009-12-01

 
 
 
 
141

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

Directory of Open Access Journals (Sweden)

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

Yan Qiongjiao

2012-07-01

142

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...entities. (v ) Related means related within the meaning...2 ) Financing entity's knowledge —(i ) In general. ...regarding financing entity's knowledge. It shall be presumed...if its business is making or managing investments, unless...

2010-04-01

143

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

Science.gov (United States)

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

Nguyen, Trieu Dong

1999-02-01

144

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

Science.gov (United States)

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

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

2014-06-01

145

Metal vapor laser including hot electrodes and integral wick  

Science.gov (United States)

A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube.

Ault, Earl R. (Livermore, CA); Alger, Terry W. (Tracy, CA)

1995-01-01

146

Stacked vapor fed amtec modules  

Science.gov (United States)

The present invention pertains to a stacked AMTEC module. The invention includes a tubular member which has an interior. The member is comprised of a ion conductor that substantially conducts ions relative to electrons, preferably a beta"-alumina solid electrolyte, positioned about the interior. A porous electrode for conducting electrons and allowing sodium ions to pass therethrough, and wherein electrons and sodium ions recombine to form sodium is positioned about the beta"-alumina solid electrolyte. The electrode is operated at a temperature and a pressure that allows the recombined sodium to vaporize. Additionally, an outer current collector grid for distributing electrons throughout the porous electrode is positioned about and contacts the porous electrode. Also included in the invention is transporting means for transporting liquid sodium to the beta"-alumina solid electrolyte of the tubular member. A transition piece is positioned about the interior of the member and contacts the transporting means. The transition piece divides the member into a first cell and a second cell such that each first and second cell has a beta"-alumina solid electrolyte, a first and second porous electrode and a grid. The transition piece conducts electrons from the interior of the tubular member. There is supply means for supplying sodium to the transporting means. Preferably the supply means is a shell which surrounds the tubular member and is operated at a temperature such that the vaporized sodium condenses thereon. Returning means for returning the condensed sodium from the shell to the transporting means provides a continuous supply of liquid sodium to the transporting means. Also, there are first conducting means for conducting electric current from the transition piece which extends through the shell, and second conducting means for conducting electric current to the grid of the first cell which extends through the shell.

Sievers, Robert K. (North Huntingdon, PA)

1989-01-01

147

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

Directory of Open Access Journals (Sweden)

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

Fitremann J. -M.

2006-11-01

148

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

149

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

150

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

Science.gov (United States)

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 emplacement causes a ground inflation correlated to a decrease of the magma discharge rate. A parametric study shows that surface displacements depend on three dimensionless numbers: the conduit aspect ratio (radius/length), the length ratio between the plug and the conduit, and the viscosity contrast between the plug and the magma column. Larger displacements are obtained for high-viscosity plugs emplaced in large aspect ratio conduits. We find that only tiltmeters or GPS located close to the vent (a few hundred meters) might record the plug emplacement. At immediate proximity of the vent, plug emplacement might even dominate the deformation signal over dome growth or magma reservoir pressurization effects. For given plug thicknesses and viscosity profiles, our model explains well the amplitude of tilt variations (from 1 to 25 ?rad) measured at Montserrat and Mt. St. Helens. We also demonstrate that at Montserrat, even if most of the tilt signal is due to shear stress induced by magma flow, pressurization beneath the plug accounts for 20% of the signal.

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

2011-06-01

151

Evaluation of a multi-layer microbraided polylactic acid fiber-reinforced conduit for peripheral nerve regeneration.  

Science.gov (United States)

We evaluated peripheral nerve regeneration using a biodegradable multi-layer microbraided polylactic acid (PLA) fiber-reinforced conduit. Biodegradability of the PLA conduit and its effectiveness as a guidance channel were examined as it was used to repair a 10 mm gap in the rat sciatic nerve. As a result, tube fragmentation was not obvious and successful regeneration through the gap occurred in all the conduits at 8 weeks after operation. These results indicate the superiority of the PLA materials and suggest that the multi-layer microbraided PLA fiber-reinforced conduits provide a promising tool for neuro-regeneration. PMID:19115095

Lu, Ming-Chin; Huang, Yen-Ting; Lin, Jia-Horng; Yao, Chun-Hsu; Lou, Ching-Wen; Tsai, Chin-Chuan; Chen, Yueh-Sheng

2009-05-01

152

26 CFR 1.881-3 - Conduit financing arrangements.  

Science.gov (United States)

...881 within the meaning of paragraph...note that pays interest annually at a rate of 8 percent...that pays no interest annually. When...note that pays interest annually at a rate of 10 percent...transactions within the meaning of...

2010-04-01

153

Overcoming short gaps in peripheral nerve repair: conduits and human acellular nerve allograft.  

Science.gov (United States)

Nerve conduits and acellular nerve allograft offer efficient and convenient tools for overcoming unexpected gaps during nerve repair. Both techniques offer guidance for migrating Schwann cells and axonal regeneration though utilizing very different scaffolds. The substantially greater amount of animal and clinical data published on nerve conduits is marked by wide discrepancies in results that may be partly explained by a still poorly defined critical repair gap and diameter size. The available information on acellular allografts appears more consistently positive though this tool is also hampered by a longer but also limited critical length. This article reviews the current relative literature and examines pertinent parameters for application of both acellular allograft and nerve conduits in overcoming short nerve gaps. PMID:24839412

Isaacs, Jonathan; Browne, Timothy

2014-06-01

154

Fluidic conduits for highly efficient purification of target species in EWOD-driven droplet microfluidics.  

Science.gov (United States)

Due to the lack of continuous flows that would wash unwanted specifies and impurities off from a target location, droplet microfluidics commonly employs a long serial dilution process to purify target species. In this work, we achieve high-purity separation for the case of electrowetting-on-dielectric (EWOD) based droplet microfluidics by introducing a "fluidic conduit" between a sample droplet and a buffer droplet. The long and slender fluidic path minimizes the diffusion and fluidic mixing between the two droplets (thus eliminating non-specific transport) but provides a conduit between them for actively transported particles (thus allowing the specific transport). The conduit is purely fluidic, stabilized chemically (e.g. using surfactants) and controlled by EWOD. The effectiveness of the technique is demonstrated by eliminating approximately 97% non-magnetic beads in just one purification step, while maintaining high collection efficiency (>99%) of magnetic beads. PMID:19636474

Shah, Gaurav J; Kim, Chang-Jin Cj

2009-08-21

155

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

156

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

157

Diabetic dyslipidemia and exercise affect coronary tone and differential regulation of conduit and microvessel K+ current.  

Science.gov (United States)

Spontaneous transient outward K(+) currents (STOCs) elicited by Ca(2+) sparks and steady-state K(+) currents modulate vascular reactivity, but effects of artery size, diabetic dyslipidemia, and exercise on these differentially regulated K(+) currents are unclear. We studied the conduit arteries and microvessels of male Yucatan swine assigned to one of three groups for 20 wk: control (C, n = 7), diabetic dyslipidemic (DD, n = 6), or treadmill-trained DD animals (DDX, n = 7). Circumflex artery blood flow velocity obtained with intracoronary Doppler and lumen diameters obtained by intravascular ultrasound enabled calculation of absolute coronary blood flow (CBF). Ca(2+) sparks were determined in pressurized microvessels, and perforated patch clamp assessed K(+) current in smooth muscle cells isolated from conduits and microvessels. Baseline CBF in DD was decreased versus C. In pressurized microvessels, Ca(2+) spark activity was significantly lower in DD versus C and DDX (P STOCs were pronounced in microvessel (approximately 35 STOCs/min) in sharp contrast to conduit cells ( approximately 2 STOCs/min). STOCs were decreased by 86% in DD versus C and DDX in microvessels; in contrast, there was no difference in STOCs across groups in conduit cells. Steady-state K(+) current in microvessels was decreased in DD and DDX versus C; in contrast, steady-state K(+) current in conduit cells was decreased in DDX versus DD and C. We conclude that steady-state K(+) current and STOCs are differentially regulated in conduit versus microvessels in health and diabetic dyslipidemia. Exercise prevented diabetic dyslipidemia-induced decreases in baseline CBF, possibly via STOC-regulated basal microvascular tone. PMID:15528227

Mokelke, E A; Dietz, N J; Eckman, D M; Nelson, M T; Sturek, M

2005-03-01

158

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

Science.gov (United States)

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

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

2014-06-20

159

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

Science.gov (United States)

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

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

2013-01-01

160

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

Science.gov (United States)

Explosive volcanic eruptions expel a mixture of pyroclasts and lithics. Pyroclasts, fragments of the juvenile magma, record the state of the magma at fragmentation in terms of porosity and crystallinity. The grain size distribution of pyroclasts is generally considered to be a direct consequence of the conditions at magma fragmentation that is mainly driven by gas overpressure in bubbles, high shear rates, contact with external water or a combination of these factors. Stress exerted by any of these processes will lead to brittle fragmentation by overcoming the magma's relaxation timescale. As a consequence, most pyroclasts exhibit angular shapes. Upon magma fragmentation, the gas pyroclast mixture is accelerated upwards and eventually ejected from the vent. The total grain size distribution deposited is a function of fragmentation conditions and transport related sorting. Porous pyroclasts are very susceptible to abrasion by particle-particle or particle-conduit wall interaction. Accordingly, pyroclastic fall deposits with angular clasts should proof a low particle abrasion upon contact to other surfaces. In an attempt to constrain the degree of particle interaction during conduit flow, monomodal batches of washed pyroclasts have been accelerated upwards by rapid decompression and subsequently investigated for their grain size distribution. In our set-up, we used a vertical cylindrical tube without surface roughness as conduit. We varied grain size (0.125-0.25; 0.5-1; 1-2 mm), porosity (0; 10; 30 %), gas-particle ratio (10 and 40%), conduit length (10 and 28 cm) and conduit diameter (2.5 and 6 cm). All ejected particles were collected after settling at the base of a 3.3 m high tank and sieved at one sieve size below starting size (half-?). Grain size reduction showed a positive correlation with starting grain size, porosity and overpressure at the vent. Although milling in a volcanic conduit may take place, porous pyroclasts are very likely to be a primary product of magma fragmentation at or close to the fragmentation level. Given the high abrasiveness of pumice, hemispherical clasts should be observed if clast break-up followed efficient clast abrasion. As a consequence, finer grained pyroclastic fall deposits do not necessarily proof efficient secondary fragmentation in the conduit but may rather reveal the influence of conduit length on 'What size of pyroclasts can be erupted'?

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

2013-12-01

 
 
 
 
161

[Apicoaortic valved conduit as an alternative method of surgical treatment of aortic stenosis - a case report].  

Science.gov (United States)

A case of a 73-year-old patient with critical aortic stenosis, porcelain aorta and occluded femoral arteries is presented. We performed apico-aortic valved conduit (A-AVC) without cardiopulmonary bypass (CPB). Hegar dilator inserted through the apex into the left ventricle allowed anastomosis of dacron tube to the apex. Valved conduit was anastomosed to the descending aorta. Both tubes were connected. Before the operation, maximal gradient through the valve was 95, after operation dropped to 33 mmHg. This method of apical anastomosis allowed to perform A-AVC without CPB in a patient with extremely high peri-operative risk while using CPB. PMID:19649999

Hirnle, Tomasz; Sobkowicz, Bozena; Juszczyk, Grzegorz; Janiszewski, Wawrzyniec; Jakubów, Piotr; Trzci?ski, Robert; Hirnle, Grzegorz; Dmitruk, Iwona; Lewczuk, Anna; Fiedorczuk, Kinga

2009-07-01

162

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

Science.gov (United States)

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

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

2013-12-01

163

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

Directory of Open Access Journals (Sweden)

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

Line A.

2006-11-01

164

Effects of large-area irradiated laser phototherapy on peripheral nerve regeneration across a large gap in a biomaterial conduit.  

Science.gov (United States)

This paper proposes a novel biodegradable nerve conduit comprising 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linked gelatin, annexed with ?-tricalcium phosphate (TCP) ceramic particles (EDC-Gelatin-TCP, EGT). In this study, the EGT-implant site in rats was irradiated using a large-area 660 nm AlGaInP diode laser (50 mW) to investigate the feasibility of laser stimulation in the regeneration of a 15-mm transected sciatic nerve. The animals were divided into three groups: a sham-irradiated group (EGT/sham); an experimental group undergoing low-level laser (LLL) therapy (EGT/laser); a control group undergoing autologous nerve grafts (autografts). Twelve weeks after implantation, walking track analysis showed a significantly higher sciatic functional index (p EGT/laser and autograft groups than in the EGT/sham group. In electrophysiological measurement, both the mean peak amplitude and the area under the compound muscle action potential curves in the EGT/laser and autograft groups showed significantly improved functional recovery than the EGT/sham group (p EGT/sham group, the EGT/laser and autograft groups displayed a reduction in muscular atrophy. Histomorphometric assessments revealed that the EGT/laser group had undergone more rapid nerve regeneration than the EGT/sham group. The laser-treated group also presented greater neural tissue area as well as larger axon diameter and thicker myelin sheath than the tube group without the laser treatment, indicating improved nerve regeneration. Thus, these assessments demonstrate that LLL therapy can accelerate the repair of a transected peripheral nerve in rats after being bridged with EGT conduit. PMID:22887896

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

2013-01-01

165

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

Science.gov (United States)

...for a Small Conduit Hydroelectric Facility and Soliciting...Project: Mary Taylor Hydroelectric Project. f. Location...Pursuant to: Federal Power Act, 16 U.S.C...proposed small conduit hydroelectric project would consist...penstock, powerhouse and substation and will obtain...

2012-01-03

166

Long-delayed gross hematuria due to portal hypertension in an alcoholic cirrhotic patient with ileal conduit urinary diversion.  

Science.gov (United States)

Bleeding varices at the stomal site is an uncommon complication of ileal conduit urinary diversion in patients with portal hypertension. We describe a case with the longest delay reported in the literature, involving the onset of massive hematuria secondary to ectopic variceal bleeding in an alcoholic cirrhotic patient with external urinary ileal conduit. PMID:25332271

Dal Moro, Fabrizio

2014-01-01

167

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

168

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

169

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

Science.gov (United States)

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

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

2012-01-01

170

A Simplified 1-D Model for Calculating CO2 Leakage through Conduits  

Energy Technology Data Exchange (ETDEWEB)

In geological CO{sub 2} storage projects, a cap rock is generally needed to prevent CO{sub 2} from leaking out of the storage formation. However, the injected CO{sub 2} may still encounter some discrete flow paths such as a conductive well or fault (here referred to as conduits) through the cap rock allowing escape of CO{sub 2} from the storage formation. As CO{sub 2} migrates upward, it may migrate into the surrounding formations. The amount of mass that is lost to the formation is called attenuation. This report describes a simplified model to calculate the CO{sub 2} mass flux at different locations of the conduit and the amount of attenuation to the surrounding formations. From the comparison among the three model results, we can conclude that the steady-state conduit model (SSCM) provides a more accurate solution than the PMC at a given discretization. When there is not a large difference between the permeability of the surrounding formation and the permeability of the conduits, and there is leak-off at the bottom formation (the formation immediately above the CO{sub 2} plume), a fine discretization is needed for an accurate solution. Based on this comparison, we propose to use the SSCM in the rapid prototype for now given it does not produce spurious oscillations, and is already in FORTRAN and therefore can be easily made into a dll for use in GoldSim.

Zhang, Y.; Oldenburg, C.M.

2011-02-15

171

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

International Nuclear Information System (INIS)

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

172

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

Science.gov (United States)

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

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

2013-12-01

173

[Clinical applications of xenopericardial conduits in surgery of ascending aortic aneurysms].  

Science.gov (United States)

At the Department of Acquired Cardiac Diseases (Head is Prof. G. I. Tsukerman), A. N. Bakulev Institute of Cardiovascular Surgery, 145 patients underwent operation for ascending aortic aneurysms, out of them the Bentalle-De Bono and the Cabrol operations were performed in 81 and 25 patients, respectively, the remaining 39 patients had palliative interventions. From February 1991 to April 1993, the clinic performed in 11 patients prosthesis of the ascending aorta with a xeno-pericardial conduit containing a bioprosthesis of the same tissue. The paper describes the technical features of bio-conduit implantation. The use of xeno-pericardial conduits facilitates the technique of applying anastomoses, lowers hemophilia and reduces the length of an operation. Hemorrhagic and thromboembolic events are expected to be reduced in late periods. At the hospital stage 1 patient died. The cause of his death was peri-coronary hematoma. Ten patients are still under observation. Repeated examinations have not detected no specific complications typical of those observed in the application of synthetic conduits. The first experience has proved to be quite promising. However, the final assessment is possible only when sufficient clinical materials are accumulated and late outcomes are studied. PMID:8148170

Malashenkov, A I; Fursov, B A; Rusanov, N I; Za?tsev, L V; Borisov, V I; Kolesnik, T F

1993-01-01

174

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

International Nuclear Information System (INIS)

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

175

Vaporizers for medical marijuana.  

Science.gov (United States)

A major concern about the medical use of marijuana is the harmful effects that come from smoking it. Vaporizers are designed to release the active ingredients in marijuana without burning it, and therefore do not release the harmful substances found in the marijuana smoke. The Institute of Medicine recommends against the long-term medical use of smoked marijuana because of carcinogens and other chemicals in the smoke. Several vaporizers are on the market, but they have not been tested in the laboratory yet. A review of two vaporizers is given. Contact information is provided. PMID:11366582

Mirken, B

1999-09-17

176

Conduit assembly for use in a nuclear reactor  

International Nuclear Information System (INIS)

In a pool-type nuclear reactor, a metal duct assembly for interconnecting the discharge duct of the pump and the inlet coolant duct of a reactor core in the pool-type nuclear reactor, the duct assembly is described comprising: an upper first tubular section adapted for connection to the discharge duct of the pump, a lower second tubular section adapted for connection with the coolant inlet duct of the reactor core, a third intermediate tubular section for interconnecting the other two sections, first and second joint means for respectively connecting one end of the intermediate section with an adjoining end of the upper section, and an opposite end of the intermediate section with an adjoining end of the lower section; and a first seal means located in each circumferential groove

177

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

Science.gov (United States)

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

Schilling, K.E.; Helmers, M.

2008-01-01

178

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

Science.gov (United States)

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

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

1982-01-01

179

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

Science.gov (United States)

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

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

2013-12-01

180

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

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

Tymokhina Elizaveta

2012-07-01

 
 
 
 
181

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

Science.gov (United States)

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

Colbourne, Jason

1999-01-01

182

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

183

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

Science.gov (United States)

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

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

2013-12-01

184

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

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

Hirahara Noriyuki

2012-01-01

185

Design criteria for stability in cable-in-conduit conductors  

Science.gov (United States)

Stability is a key point in the design of large conductors for application in fusion machines such as NET or ITER. In the electromagnetically noisy environment characterizing the surroundings of a plasma, the superconductor should be stable against all expected heat deposition, including a.c. losses driven by plasma disruptions. Since all sources of thermal perturbations cannot be adequately identified, predicted or calculated, the design must allow for suitable margins. To ensure this, stability must be considered as a design criterion which is checked by means of analytical and numerical methods and later calibrated against experimental measurements of transient heat transfer and stability behaviour. In this the procedure developed at NET is described for the design and analysis of the stability margin of conductors for the toroidal and poloidal field coils. These methods are applied to the generation of stability curves and maps which are used to set operating limits for the 40 kA NET conductor. The design criteria and analytical methods can be appropriately modified for other conductors and coil applications.

Bottura, L.; Mitchell, N.; Minervini, J. V.

186

Vapor pressures and enthalpies of vaporization of azides  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-11-15

187

Progress of electrospun fibers as nerve conduits for neural tissue repair.  

Science.gov (United States)

Nerve tissue regeneration approaches have gained much attention in recent years, and nerve conduits (NCs), which facilitate nerve tissue regeneration, have become an attractive alternative to nerve autologous graft. Several methods are proposed to fabricate NCs, including electrospinning, which is a widely used approach for NCs and other tissue scaffolds, and has advantages such as the ability to control the thickness, diameter and porosity of fibers, as well as its simple experimental set up. This article gives an overview of electrospun fibers for nerve conduits utilized in peripheral and central nerve regeneration. Natural and synthetic materials with different mechanical strength, degradation rates and biocompatibility are proposed. Several bioactive proteins that can help the process of nerve regeneration are introduced. Finally, some approaches to control the morphology of electrospun fibers and to deliver bioactive proteins are discussed in detail. PMID:25325242

Mu, Ying; Wu, Fei; Lu, Yingrong; Wei, Liangming; Yuan, Weien

2014-08-01

188

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

189

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

International Nuclear Information System (INIS)

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

190

Lutter contre l’obésité en gouvernant les conduites des consommateurs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Si, en France, le rôle des facteurs socio-structurels a été souligné au cours de la mise sur agenda du problème de l’obésité et du surpoids, les dispositifs déployés ont surtout visé à responsabiliser les individus. Cette politique est en cela représentative des transformations que connaissent les pays occidentaux, où l’on observe le déploiement de dispositifs qui visent à résoudre des problèmes publics par le gouvernement des conduites des individus, pensés ...

Bergeron, Henri; Castel, Patrick; Nouguez, Etienne

2014-01-01

191

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

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

Topuzovi? ?edomir

2012-01-01

192

Evaluation of PRGD/FK506/NGF conduits for peripheral nerve regeneration in rats  

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Full Text Available Context : Both tacrolimus (FK506 and nerve growth factor (NGF enhance peripheral nerve regeneration, and in vitro experimental results demonstrate that the combination of FK506 and NGF increased neurite outgrowth compared with either treatment alone. Aim : To determine if the combination of FK506 and NGF benefits peripheral nerve regeneration compared with either treatment alone in vivo. Settings and Design : Rat sciatic nerves were cut off to form a 10 mm defect and repaired with the nerve conduits. All of the 32 Wistar rats were randomly divided into 4 groups: Group A: RGD peptide modification of poly{(lactic acid-co-[(glycolic acid-alt-(L-lysine]} (PRGD/FK506/NGF; Group B: PRGD/FK506; Group C: PRGD/NGF; and Group D: autologous nerves. Materials and Methods : At 3 months after surgery, the regenerated rat sciatic nerve was evaluated by electrophysiology, calf triceps wet weight recovery rate, and histologic assessment. Statistical Analysis Used : The SPSS 10.0 software (Bizinsight, Beijing China was used for statistical analysis. Results : The compound muscle action potentials (CMAPs of groups A and D were significantly stronger than those of groups B and C. The calf triceps wet weight recovery rate of groups A and D were higher than those of groups B and C. The regenerated nerves of groups A and D were more mature than those of groups B and C. There was no significant difference between groups A and D. Conclusions : PRGD/FK506/NGF sustained-release nerve conduits are more effective in regenerating nerves than both PRGD/FK506 sustained-release nerve conduits and PRGD/NGF sustained-release nerve conduits. The effect is as good as that of an autograft.

Jifeng Huang

2010-01-01

193

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

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

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

2012-01-01

194

Fibrosing Mediastinitis with Severe Bilateral Pulmonary Artery Narrowing: RV–RPA Bypass with a Homograft Conduit  

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Although fibrosing mediastinitis is uncommon, it is a devastating sequela of certain granulomatous diseases. The compression of mediastinal structures can lead to severe cardiopulmonary symptoms. We report the case of a 50-year-old woman who presented with severe bilateral branch pulmonary artery compression 6 months after bilateral pulmonary artery stenting. We performed bypass surgery with use of a homograft conduit. Seven months postoperatively, the homograft and stent in the right pulmona...

Gustafson, Monica R.; Moulton, Michael J.

2012-01-01

195

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

196

Simulation numérique de la convection naturelle laminaire dans une conduite verticale  

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

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

2007-01-01

197

Ceramic fiber blanket wrap for fire protection of cable trays and conduits  

International Nuclear Information System (INIS)

In some areas of nuclear power plants, cables of redundant electrical systems, which are necessary for the safe shutdown of the reactor, are in close proximity. If a fire should occur in one of these areas, both electrical systems could be destroyed before the fire is extinguished and control of the reactor may be lost. A ceramic fiber blanket was evaluated as a fire protective wrap around cable trays and conduits. 2 refs

198

Fuel Vaporization Effects  

Science.gov (United States)

A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

Bosque, M. A.

1983-01-01

199

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

Science.gov (United States)

Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

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

2014-01-01

200

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

International Nuclear Information System (INIS)

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

 
 
 
 
201

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

Science.gov (United States)

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

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

2014-08-01

202

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

Science.gov (United States)

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

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

2014-02-01

203

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

Scientific Electronic Library Online (English)

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

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

1999-12-01

204

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

205

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. 3 figs.

Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

1983-02-08

206

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

International Nuclear Information System (INIS)

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

207

Application of near real-time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii  

Science.gov (United States)

Radial Semblance is applied to broadband seismic network data to provide source locations of Very-Long-Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

Dawson, P.; Whilldin, D.; Chouet, B.

2004-01-01

208

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

Science.gov (United States)

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

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

2014-05-01

209

Overfill testing of anaesthetic vaporizers.  

Science.gov (United States)

We tested six anaesthetic vaporizers with keyed filler adaptors to see if it was possible to overfill them. For those vaporizers which could be overfilled, the maximum level of overfill was determined and the effect of overfilling on the vaporizer output concentration was measured. Three of the vaporizers, the TEC 4, PPV Mk 1 and MIE Vapamasta 5, could be overfilled. In the case of the TEC 4 and PPV vaporizers, overfilling by more than 100 ml caused a large increase in the vaporizer output concentration. Overfilling the Vapamasta 5 by this amount caused the output concentration to decrease. PMID:7880686

Palayiwa, E; Hahn, C E

1995-01-01

210

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

Science.gov (United States)

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

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

2013-06-01

211

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

212

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

213

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

Science.gov (United States)

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

Summers, P.; Dunham, E. M.

2013-12-01

214

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

Science.gov (United States)

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

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

2014-05-01

215

Muonium formation in vapors  

International Nuclear Information System (INIS)

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

216

Gas slug rise in open versus plugged basaltic conduits: the transition from Strombolian to sustained volcanic eruptions  

Science.gov (United States)

Strombolian eruptions are characterized by low-energy explosive activity, which may repeat, at fairly regular intervals, for long periods of time. Explosions at the vent are thought to result from the arrival of discrete slugs of magmatic gas that have risen through the magmatic plumbing system. We develop a one dimensional, analytical model of gas slug rise in a volcanic conduit which we use to investigate the controls on the dynamics of Strombolian eruptions. We consider a partially-filled, cylindrical conduit containing degassed magma, that is initially in magma-static equilibrium with a constant pressure magma reservoir at depth. We introduce a slug of gas at the base of the conduit and consider the temporal evolution of the pressure distribution in the conduit, and the motion of the magma above and below the slug, as the slug rises, decompresses, and expands isothermally. We validate our model against published data for gas slugs rising and decompressing in a vertical pipe [James et al., 2008, Geological Society of London, Special Publications 307, 147-167] by imposing the condition of zero magma-flux at the base of the conduit, and constant pressure at the top; we find excellent agreement. If we impose the more geologically-sound condition of constant pressure at the base of the conduit, we can consider two scenarios of volcanological relevance: 1) Vent plugged with cooler, more-viscous magma. In this case, as the slug rises and expands beneath the plug, it pushes the degassed magma below it down the conduit, consequently, magma re-enters the chamber from the base of the conduit. The slug reaches the viscous plug at the top of the conduit with a significant over-pressure; this may be sufficient to disrupt the plug, causing a Strombolian explosion, or the gas may percolate away. Fresh magma then moves up from the chamber, into the conduit to restore magma-static equilibrium. 2) Open vent. As the slug rises and expands, the volume of magma held in the falling-film that encircles the slug increases. Since this film is supported viscously by the conduit walls, it does not contribute to the magma-static pressure at the base of the conduit which, therefore, decreases, causing fresh magma to flow upwards. Fresh magma entering the base of the conduit may cause a new slug to form, either through decompression and exsolution, or by tapping a gas-rich layer at an asperity, or at the chamber roof. In either case, scenario 1 (plugged vent) will lead to periodic, Strombolian eruption, whilst scenario 2 (open vent) will lead to sustained eruption at higher discharge rate. A noteworthy feature of the model is that the conduit is recharged with fresh magma following slug rise, even if no magma is erupted at the surface. We apply our model to the case of Stromboli, and compare model output with monitoring observations. We find that the most important parameters controlling eruption style and vigour are magma viscosity, mass of gas in the slug, and the ratio of slug radius to conduit radius. Our findings potentially impact the dangerous transition from 'touristic' Strombolian activity to more-hazardous paroxysmal activity.

Llewellin, Ed; Mathias, Simon; Del Bello, Elisabetta; Lane, Steve; Taddeucci, Jacopo

2010-05-01

217

Visual Observation of Vapor Film Collapse Behavior During Vapor Explosion  

International Nuclear Information System (INIS)

During severe accident of a light water reactor, various thermal hydraulic phenomena including vapor explosion could threaten the integrity of the containment vessel. Thermal detonation model is proposed to describe the vapor explosion. According to the model, several processes should be sequentially satisfied for the trigger phenomena of the vapor explosion. One of the most important processes for the trigger phenomena is the vapor film collapse around high temperature molten material droplets. In the present study, the vapor film collapse behavior around high temperature solid particle submerged into water was experimentally investigated by attacking a pressure pulse to the vapor film on a high temperature sold particle. The interfacial phenomena between vapor and water were measure by using a high-speed video camera of the maximum speed of 40,500 fps. The visual data obtained were processed with visual data processing techniques. That is, the average vapor film thickness was estimated, dynamic behaviors of the interfaces were analyzed with PIV technique and the interface movement was estimated with the digital auto correlation techniques from the visual data obtained. Furthermore, the transients of the temperature and pressure were simultaneously measured. The interfacial temperatures between vapor and water, and between molted liquid and water are analytically estimated by solving the heat conduction equation with the data obtained as the boundary conditions. It i obtained as the boundary conditions. It is clarified that vapor collapse by pressure pulse occurs homogeneously around the vapor film surface on a high temperature particle. Microscopic information are obtained from the visual data by using visual data processing technique, PIV technique and digital auto-correlation technique. At the time the vapor film surface changes to white, the saturation temperature exceeds the interfacial temperature. The microscopic vapor film collapse behavior indicates the possibility of the phase change at the vapor film collapse. (authors)

218

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-05-01

219

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

LENUS (Irish Health Repository)

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

Healy, David G

2012-02-03

220

Water vaporization on Ceres  

Science.gov (United States)

A search is presently conducted for OH generated by the photodissociation of atmospheric water vapor in long-exposure IUE spectra of the region around Ceres. A statistically significant detection of OH is noted in an exposure off the northern limb of Ceres after perihelion. The amount of OH is consistent with a polar cap that might be replenished during winter by subsurface percolation, but which dissipates in summer.

A'Hearn, Michael F.; Feldman, Paul D.

1992-01-01

 
 
 
 
221

Chemical vapor composites (CVC)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Reagan, P.

1993-01-01

222

What Does the Mean Mean?  

Science.gov (United States)

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

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

2011-01-01

223

Gasoline vapor biofiltration  

Energy Technology Data Exchange (ETDEWEB)

While gasoline vapor emissions are common sources of air pollution, very few results have been published on the biofilter biodegradation of gasoline vapors in flowing waste gases. This investigation reports on a bench-scale biofilter of an ID of 50 mm and a bed height of 850 mm with an inexpensive fire clay chip medium as a packing material. The biofilter was inoculated with a concentrate of a mixed culture of the common microflora. After an acclimatization period of three weeks, loading tests were carried out at increasing gasoline inlet concentrations at a constant Empty Bed Retention Time (EBRT) of 16 min. Evaluating the removal rate and efficiency of aliphatic and aromatic fractions of the gasoline vapor, it was found that in a range of overall organic loading (OL{sub TPH}) up to 33.6 g/m{sup 3} h the removal efficiency of aromatic hydrocarbons decreased from 90 to 70 %, while that of the aliphatic components decreased much more significantly from 60 to 10 % after six months of operation. The removal rate and efficiency achieved for total petroleum hydrocarbons were 13 g/m{sup 3} h and 45 %, respectively. The microbial strains and genera of culturable cells in the inoculum and in the biofilm after six months of gasoline degradation were evaluated. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Paca, J.; Halecky, M. [Institute of Chemical Technology, Department of Fermentation Chemistry and Bioengineering, Prague (Czech Republic); Maryska, M. [Institute of Chemical Technology, Department of Glass and Ceramics, Prague (Czech Republic); Jones, K. [South Texas Environmental Institute, Texas A and M University-Kingsville, Kingsville (United States)

2007-10-15

224

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

225

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

Science.gov (United States)

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

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

2013-01-01

226

A dual-pressure boundary condition for use in simulations of bifurcating conduits.  

Science.gov (United States)

A dual-pressure boundary condition has been developed for computational modelling of bifurcating conduits. The condition involves the imposition of a constant pressure on one branch while adjusting iteratively the pressure on the other branch until the desired flow division is obtained. The dual-pressure condition eliminates the need for specifying fully-developed flow conditions, which thereby enables significant reduction of the outlet branch lengths. The dual-pressure condition is suitable for both steady and time-periodic simulations of laminar or turbulent flows. PMID:12405605

Gin, Ron; Straatman, Anthony G; Steinman, David A

2002-10-01

227

Génération, visualisation et évaluation d'images HDR : application à la simulation de conduite nocturne  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cette thèse se situe à l'interface de deux des sujets de recherche du LEPSi8S, la perception et la réalité virtuelle, appliqués aux transports routiers. L'objectif de la thèse est d'améliorer l'état de l'art concernant le rendu des images de synthèse pour les simulateurs de conduite. L'axe privilégié est le réalisme perceptif des images. L'approche retenue propose un mode de rendu High Dynamic Range, qui permet de générer une image en luminance. La technique proposée permet de ...

Petit, Josselin

2010-01-01

228

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

International Nuclear Information System (INIS)

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

229

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

International Nuclear Information System (INIS)

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

230

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-06-15

231

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

Science.gov (United States)

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

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

2007-10-02

232

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

Science.gov (United States)

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

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

2014-03-24

233

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)

234

Modelling magma ascent in volcanic conduit based on steady-state and transient approaches.  

Science.gov (United States)

We model magma ascent in volcanic conduit using sets of mathematical models including steady-state model and two transient models. All models study the flow range from bubbly liquid to gas-particle dispersion. Steady-state model takes into account gas filtration through interconnected bubbles and overpressure development due to the viscous resistance to bubble growth. Fragmentation criterion is based on critical bubble overpressure. The model predicts presence of two solutions for fixed parameters in the magma chamber. One solution corresponds to lava dome extrusion, the other to explosive eruption. Abrupt transition between this two regimes is possible with slow variation of the system parameters. Transient models simulate the case of initiation of explosive eruption by disruption of the plug which covers the top of the conduit. The influence of intensity of mass transfer between melt and growing bubbles and of influx of the water from porous wallrocks (phreatomagmatic eruption) is studied. Two end-member cases of diffusion is considered - equilibrium and absence of mass transfer. For the equilibrium case the duration of explosive eruption is about an hour and activity has pulses due to step-like fragmentation of magma. For the other case the duration is about several minutes and one pulse of discharge occurs. Results of the simulations are in good agreement with field data for the Soufriere Hills Volcano (Montserrat). Calculations of phreatomagmatic eruptions show that influx of water from the porous aquifer can significantly increase discharge rate and produce its oscillations with a period of several minutes.

Melnik, O. E.; Barmin, A. A.; Starostin, A. B.; Mason, R.

2003-04-01

235

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

236

Biofiltration of gasoline vapors from a soil vapor extraction system  

International Nuclear Information System (INIS)

Biofiltration was used to treat gasoline vapors produced by soil vapor extraction (SVE) from an area contaminated by a leaking underground gasoline tank. The biofilter was installed upstream of an activated carbon unit. The biofilter removed 25--50% of the vapors in the early months of the project, when more volatile components dominated. Later, the vapors were mostly less volatile materials, and the biofilter removed 40--75%. This behavior was predicted by bench scale experiments. The biofilter was economically successful, and the project provided data for projecting the economic viability of biofilters in similar applications

237

Thermal conductivity of mercury vapor  

Energy Technology Data Exchange (ETDEWEB)

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

Siegel, J R

1977-01-01

238

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

CERN Document Server

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

Costa, A; Costa, Antonio; Macedonio, Giovanni

2002-01-01

239

Use of nerve conduits for peripheral nerve injury repair: A Web of Science-based literature analysis?  

Science.gov (United States)

OBJECTIVE: To identify global research trends in the use of nerve conduits for peripheral nerve injury repair. DATA RETRIEVAL: Numerous basic and clinical studies on nerve conduits for peripheral nerve injury repair were performed between 2002–2011. We performed a bibliometric analysis of the institutions, authors, and hot topics in the field, from the Web of Science, using the key words peripheral nerve and conduit or tube. SELECTION CRITERIA: Inclusion criteria: peer-reviewed published articles on nerve conduits for peripheral nerve injury repair, indexed in the Web of Science; original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. Exclusion criteria: articles requiring manual searching or telephone access; documents not published in the public domain; and several corrected papers. MAIN OUTCOME MEASURES: (a) Annual publication output; (b) publication type; (c) publication by research field; (d) publication by journal; (e) publication by funding agency; (f) publication by author; (g) publication by country and institution; (h) publications by institution in China; (i) most-cited papers. RESULTS: A total of 793 publications on the use of nerve conduits for peripheral nerve injury repair were retrieved from the Web of Science between 2002–2011. The number of publications gradually increased over the 10-year study period. Articles constituted the main type of publication. The most prolific journals were Biomaterials, Microsurgery, and Journal of Biomedical Materials Research Part A. The National Natural Science Foundation of China supported 27 papers, more than any other funding agency. Of the 793 publications, almost half came from American and Chinese authors and institutions. CONCLUSION: Nerve conduits have been studied extensively for peripheral nerve regeneration; however, many problems remain in this field, which are difficult for researchers to reach a consensus.

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

2012-01-01

240

High microsatellite and mitochondrial diversity in Anatolian native horse breeds shows Anatolia as a genetic conduit between Europe and Asia.  

Science.gov (United States)

The horse has been a food source, but more importantly, it has been a means for transport. Its domestication was one of the crucial steps in the history of human civilization. Despite the archaeological and molecular studies carried out on the history of horse domestication, which would contribute to conservation of the breeds, the details of the domestication of horses still remain to be resolved. We employed 21 microsatellite loci and mitochondrial control region partial sequences to analyse genetic variability within and among four Anatolian native horse breeds, Ayvac?k Pony, Malakan Horse, H?n?s Horse and Canik Horse, as well as samples from indigenous horses of unknown breed ancestry. The aims of the study were twofold: first, to produce data from the prehistorically and historically important land bridge, Anatolia, in order to assess its role in horse domestication and second, to analyse the data from a conservation perspective to help the ministry improve conservation and management strategies regarding native horse breeds. Even though the microsatellite data revealed a high allelic diversity, 98% of the genetic variation partitioned within groups. Genetic structure did not correlate with a breed or geographic origin. High diversity was also detected in mtDNA control region sequence analysis. Frequencies of two haplogroups (HC and HF) revealed a cline between Asia and Europe, suggesting Anatolia as a probable connection route between the two continents. This first detailed genetic study on Anatolian horse breeds revealed high diversity among horse mtDNA haplogroups in Anatolia and suggested Anatolia's role as a conduit between the two continents. The study also provides an important basis for conservation practices in Turkey. PMID:22497212

Koban, E; Denizci, M; Aslan, O; Aktoprakligil, D; Aksu, S; Bower, M; Balcioglu, B K; Ozdemir Bahadir, A; Bilgin, R; Erdag, B; Bagis, H; Arat, S

2012-08-01

 
 
 
 
241

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

242

Fluorescence and nonradiative processes of dioxin vapors  

Science.gov (United States)

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

Itoh, Takao; Hashimoto, Ryuso

2014-03-01

243

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

244

Neural regeneration in a novel nerve conduit across a large gap of the transected sciatic nerve in rats with low-level laser phototherapy.  

Science.gov (United States)

This study proposes a biodegradable nerve conduit comprising 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) cross-linked gelatin annexed with ?-tricalcium phosphate (?-TCP) ceramic particles (EDC-gelatin-TCP, EGT). For this study, the EGT-implant site in rats was irradiated using 660-nm GaAlAsP laser diodes (50 mW) for trigger point therapy to investigate the use of low-level laser (LLL) stimulation in the regeneration of a 15-mm transected sciatic nerve. Animals were divided into three groups: a control group undergoing autologous nerve graft (autograft); a sham-irradiated group (EGT), and an experimental group undergoing laser stimulation (EGT/LS). Two trigger points on the surgical incision along the sciatic nerve were irradiated transcutaneously for 2 min daily for 10 consecutive days. Twelve weeks after implantation, walking track analysis showed a significantly higher sciatic functional index (SFI; p EGT/LS groups, compared to the EGT group. In the electrophysiological measurement, the mean recovery index (peak amplitude and area) of the compound muscle action potential curves in the autograft and EGT/LS groups showed significantly improved functional recovery than in the EGT group (p EGT group, the autograft and EGT/LS groups showed a reduction in muscular atrophy. Histomorphometric assessments showed that the EGT/LS group had undergone more rapid nerve regeneration than the EGT group. Therefore, motor function, electrophysiological reaction, muscular reinnervation, and histomorphometric assessments demonstrate that LLL therapy can accelerate the repair of a 15-mm transected peripheral nerve in rats after being bridged with the EGT nerve conduit. PMID:23427146

Shen, Chiung-Chyi; Yang, Yi-Chin; Huang, Tsung-Bin; Chan, Shiuh-Chuan; Liu, Bai-Shuan

2013-10-01

245

On the relationship between water vapor over the oceans and sea surface temperature  

Science.gov (United States)

Monthly mean precipitable water data obtained from passive microwave radiometry were correlated with the National Meteorological Center (NMC) blended sea surface temperature data. It is shown that the monthly mean water vapor content of the atmosphere above the oceans can generally be prescribed from the sea surface temperature with a standard deviation of 0.36 g/sq cm. The form of the relationship between precipitable water and sea surface temperature in the range T(sub s) greater than 18 C also resembles that predicted from simple arguments based on the Clausius-Clapeyron relationship. The annual cycle of the globally integrated mass of Scanning Multichannel Microwave Radiometer (SMMR) water vapor is shown to differ from analyses of other water vapor data in both phase and amplitude and these differences point to a significant influence of the continents on water vapor. Regional scale analyses of water vapor demonstrate that monthly averaged water vapor data, when contrasted with the bulk sea surface temperature relationship developed in this study, reflect various known characteristics of the time mean large-scale circulation over the oceans. A water vapor parameter is introduced to highlight the effects of large-scale motion on atmospheric water vapor. Based on the magnitude of this parameter, it is shown that the effects of large-scale flow on precipitable water vapor are regionally dependent, but for the most part, the influence of circulation is generally less than about + or - 20 percent of the seasonal mean.

Stephens, Graeme L.

1989-01-01

246

Venting means for nuclear reactors  

International Nuclear Information System (INIS)

This patent describes a pressurized water reactor comprising a pressure vessel having a removable upper head attached to the top thereof with at least one pair of coolant inlet and outlet nozzles. The improvement consists of an internal venting conduit having one end disposed inside the space defined by the upper head, and the other end being connected to a high pressure container outside the reactor, the conduit passing through the wall of the pressure vessel or outlet nozzle of the reactor

247

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

International Nuclear Information System (INIS)

A likely source of a quench in cable-in-conduit internally cooled superconductors (CCICS) is frictional heating due to strand motion in the cable. Most previous studies on CCICS stability evaluate the amount of energy needed to quench the conductor by assuming that the disturbance energy is uniformly distributed across the cross section. The authors believe that these studies are too optimistic, and have studied the stability of CCICS assuming that the disturbance energy is abruptly input into a small part of a single strand. To perform this analysis, the transient heat transfer characteristics of supercritical helium (SHE) have been measured. This paper presents the transient heat transfer characteristics of SHE and the results of the stability analysis

248

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

Science.gov (United States)

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

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

2014-05-01

249

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

Science.gov (United States)

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

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

2013-01-01

250

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

International Nuclear Information System (INIS)

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

251

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

252

Histological and histochemical changes in the colon mucosa after ureterosigmoidostomy or colonic conduit.  

Science.gov (United States)

A study was made of 22 patients previously subjected to urinary diversion, 12 with ureterosigmoidostomy and 10 with colon conduit. The histological and histochemical examination of biopsies of intestinal mucosa near to and far from the ureteral orifices showed transformations with considerable inflammatory infiltration, variations in the composition of the acid mucins with a prevalence of sialomucins, lengthening and branching of the glandular crypts, and sometimes dysplasias of the epithelium. These structural modifications are typical of transitional mucosa. Transitional mucosa might reflect an aspecific reaction of the intestinal mucosa or alternatively it might signify a precancerous condition. Its presence in intestinal diversions suggests the advisability of careful follow-up in all patients subjected to this operation. PMID:2463923

Tomasino, R M; Morello, V; Latteri, M A; Spinnato, G; Pantuso, G; Orestano, F

1988-01-01

253

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

Science.gov (United States)

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

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

2013-11-01

254

Constrained Vapor Bubble  

Science.gov (United States)

The nonisothermal Constrained Vapor Bubble, CVB, is being studied to enhance the understanding of passive systems controlled by interfacial phenomena. The study is multifaceted: 1) it is a basic scientific study in interfacial phenomena, fluid physics and thermodynamics; 2) it is a basic study in thermal transport; and 3) it is a study of a heat exchanger. The research is synergistic in that CVB research requires a microgravity environment and the space program needs thermal control systems like the CVB. Ground based studies are being done as a precursor to flight experiment. The results demonstrate that experimental techniques for the direct measurement of the fundamental operating parameters (temperature, pressure, and interfacial curvature fields) have been developed. Fluid flow and change-of-phase heat transfer are a function of the temperature field and the vapor bubble shape, which can be measured using an Image Analyzing Interferometer. The CVB for a microgravity environment, has various thin film regions that are of both basic and applied interest. Generically, a CVB is formed by underfilling an evacuated enclosure with a liquid. Classification depends on shape and Bond number. The specific CVB discussed herein was formed in a fused silica cell with inside dimensions of 3x3x40 mm and, therefore, can be viewed as a large version of a micro heat pipe. Since the dimensions are relatively large for a passive system, most of the liquid flow occurs under a small capillary pressure difference. Therefore, we can classify the discussed system as a low capillary pressure system. The studies discussed herein were done in a 1-g environment (Bond Number = 3.6) to obtain experience to design a microgravity experiment for a future NASA flight where low capillary pressure systems should prove more useful. The flight experiment is tentatively scheduled for the year 2000. The SCR was passed on September 16, 1997. The RDR is tentatively scheduled for October, 1998.

Huang, J.; Karthikeyan, M.; Plawsky, J.; Wayner, P. C., Jr.

1999-01-01

255

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

256

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

Directory of Open Access Journals (Sweden)

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

G. G. J. Ernst

2005-06-01

257

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

258

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

259

Vapor phase heat transport systems  

Science.gov (United States)

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

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

1985-09-01

260

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

Science.gov (United States)

... Allocation of expenses by real estate mortgage investment conduits...expenses —(1) In general. A real estate mortgage investment...C) thereof, or (D) A real estate investment trust. ...amount of such expenses by the number of days in that calendar...

2010-04-01

 
 
 
 
261

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

Science.gov (United States)

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

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

2014-08-01

262

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

263

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

264

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.

265

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

Science.gov (United States)

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

Lachenbruch, Arthur H.; Nathenson, Manuel

1976-01-01

266

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

Scientific Electronic Library Online (English)

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

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

2010-12-01

267

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

Scientific Electronic Library Online (English)

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

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

268

Vapor pressure measured with inflatable plastic bag  

Science.gov (United States)

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

1965-01-01

269

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

270

Vapor Pressure, Vapor Composition and Fractional Vaporization of High Temperature Lavas on Io  

Science.gov (United States)

Observations show that Io's atmosphere is dominated by SO2 and other sulfur and sulfur oxide species, with minor amounts of Na, K, and Cl gases. Theoretical modeling and recent observations show that NaCl, which is produced volcanically, is a constituent of the atmosphere. Recent Galileo, HST and ground-based observations show that some volcanic hot spots on Io have extremely high temperatures, in the range 1400-1900 K. At similar temperatures in laboratory experiments, molten silicates and oxides have significant vapor pressures of Na, K, SiO, Fe, Mg, and other gases. Thus vaporization of these species from high temperature lavas on Io seems likely. We therefore modeled the vaporization of silicate and oxide lavas suggested for Io. Our results for vapor chemistry are reported here. The effects of fractional vaporization on lava chemistry are given in a companion abstract by Kargel et al.

Fegley, B., Jr.; Schaefer, L.; Kargel, J. S.

2003-01-01

271

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

272

Passive vapor extraction feasibility study  

Energy Technology Data Exchange (ETDEWEB)

Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft{sup 3}/min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft{sup 3}/min air flow rates, passive vapor extraction is more cost effective below 100 ppm.

Rohay, V.J.

1994-06-30

273

Passive vapor extraction feasibility study  

International Nuclear Information System (INIS)

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

274

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

275

Supercritical microgravity droplet vaporization  

Science.gov (United States)

Supercritical droplet vaporization is an important issue in many combustion systems, such as liquid fueled rockets and compression-ignition (diesel) engines. In order to study the details of droplet behavior at these conditions, an experiment was designed to provide a gas phase environment which is above the critical pressure and critical temperature of a single liquid droplet. In general, the droplet begins as a cold droplet in the hot, high pressure environment. In order to eliminate disruptions to the droplet by convective motion in the gas, forced and natural convection gas motion are required to be small. Implementation of this requirement for forced convection is straightforward, while reduction of natural convection is achieved by reduction in the g-level for the experiment. The resulting experiment consists of a rig which can stably position a droplet without restraint in a high-pressure, high temperature gas field in microgravity. The microgravity field is currently achieved by dropping the device in the NASA Lewis 2.2 second drop tower. The performance of the experimental device and results to date are presented.

Hartfield, J.; Curtis, E.; Farrell, P.

1990-01-01

276

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

277

A stratospheric water vapor feedback  

Science.gov (United States)

Variations in stratospheric water vapor play a role in the evolution of our climate. We show here that variations in water vapor since 2004 can be traced to tropical tropopause layer (TTL) temperature perturbations from at least three processes: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the troposphere. The connection between stratospheric water vapor and the temperature of the troposphere implies the existence of a stratospheric water vapor feedback. We estimate the feedback in a chemistry-climate model to have a magnitude of +0.3 W/m2/K, which could be a significant contributor to the overall climate sensitivity. About two-thirds of the feedback comes from the extratropical stratosphere below ~16 km (the lowermost stratosphere), with the rest coming from the stratosphere above ~16 km (the overworld).

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

2013-12-01

278

Basic study on vapor suppression  

International Nuclear Information System (INIS)

The condensation of steam jets in highly subcooled water was studied experimentally and theoretically. Steam was discharged downward into pool water through single straight nozzle. The length (height) of the vapor cone formed of continuous vapor phase was determined by photographs and temperature distributions. It increased 0.4 to 2.5 x d (d: nozzle diameter) with steam velocity at the nozzle exit, 120 to 640 m/s. The angles of divergence of jets were about 20 to 400. A turbulent diffusion model was proposed that the length of vapor cone was calculated from turbulent diffusion of heat in the mixing zone between the vapor cone and the surrounding medium. Calculated results were agreeable to experimental values. (U.S.)

279

Metal Vapor Laser Contaminant Study.  

Science.gov (United States)

Contaminants evolved during lead and copper vapor laser operation are identified. The principal long term source is the hot high density alumina discharge tube. Procedures for decontamination down to 10 to the -6 mm partial pressure are described. Such de...

T. W. Karras, B. G. Bricks

1980-01-01

280

Understanding Latent Heat of Vaporization.  

Science.gov (United States)

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

Linz, Ed

1995-01-01

 
 
 
 
281

Portable vapor diffusion coefficient meter  

Science.gov (United States)

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

Ho, Clifford K. (Albuquerque, NM)

2007-06-12

282

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

283

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)

284

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.

285

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

286

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

Directory of Open Access Journals (Sweden)

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

Verstraete Alain G.

2009-03-01

287

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)

288

Vapor deposition of hardened niobium  

International Nuclear Information System (INIS)

A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800 to ca. 9000 C, and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed

289

Analogue modeling of slug-related geophysical signals in open vs. closed conduits: implications for Strombolian eruption dynamics.  

Science.gov (United States)

Strombolian activity is characterized by low-intensity, impulsive explosions, which may occur repeatedly over long periods of time. Strombolian explosions are thought to result from the bursting of discrete pockets (slugs) of magmatic gas that, deep in the plumbing system, decouple from the surrounding, low-viscosity magma and ascend through it. There are several different physical parameters that control the ascent and explosion of slugs and influence the nature of the resulting geophysical signals, including slug volume, conduit geometry and magma rheology. In this study, we investigate the role of vertical contrasts in magma rheology within the conduit, and the nature of the boundary conditions on magma flow at the top and bottom of the conduit; these parameters have so far received little attention in combination with slug flow. Variations in magma rheology in the conduit are perhaps more a rule than an exception at persistently active volcanoes, where gas-rich, crystal poor magmas share the conduit with their degassed and partially-crystallized counterpart, and where stiffened plugs develop quickly in vents in repose. We have performed analogue experiments to investigate pressure and force changes resulting from the expansion and bursting of a slug in a liquid-filled pipe. The experimental set up is equipped with a high speed camera and pressure sensors, and the large vertical pressure gradient of the natural system is replicated by reducing the pressure at the top of the pipe with a vacuum pump. The lower end of the pipe may be either 'open' (constant pressure condition) or 'closed' (zero flux condition). The former is perhaps more geologically-sound, modelling a conduit that is connected with a constant pressure reservoir. The top of the pipe was either left fully open (to the constant-pressure partial vacuum) or 'plugged' with a layer of higher viscosity liquid, the thickness of which was systematically varied. Measured pressure variations inside and outside the pipe were correlated with high speed imagery of slug expansion and bursting. Data show that, during slug flow, open-base conditions develop an upward flux at the base of the pipe, which attenuates the magnitude of the pressure transients. We also find that rheological stiffening in the upper part of the pipe dramatically changes the magnitude of the observed pressure transients, favoring a more impulsive and more energetic pressure release into the overlying atmosphere. We discuss the implications of our results for the interpretation of the geophysical signals that underpin most of the monitoring systems at persistently active, mafic volcanoes.

Del Bello, E.; Lane, S. J.; Llewellin, E. W.; Taddeucci, J.; James, M. R.; Scarlato, P.

2012-04-01

290

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

Science.gov (United States)

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

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

2013-12-01

291

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

Science.gov (United States)

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

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

2011-08-01

292

controlled water vapor conditions  

Directory of Open Access Journals (Sweden)

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

M.A. V\\u00E1squez-A.

2007-01-01

293

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

International Nuclear Information System (INIS)

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

294

Stimulated prostacyclin release by conduits used for coronary artery bypass grafting.  

Science.gov (United States)

A direct comparison of the three coronary artery bypass conduits internal mammary artery (IMA), right gastroepiploic artery (RGEA), and saphenous vein (SV) concerning arachidonic acid (AA) stimulated release of the vasodilating and platelet inhibiting mediator prostacyclin was the aim of the present study. Pieces of saphenous vein (n = 16), right gastroepiploic artery (n = 8), and internal mammary artery (n = 19) were obtained from patients undergoing coronary artery bypass grafting. After a resting phase of 30 min in HEPES medium arachidonic acid (AA) was added in order to stimulate prostacyclin release. Time-dependent production of the stable prostacyclin metabolite 6-keto-prostaglandin F1 alpha was determined following stimulation. Under basal conditions the IMA (12.4 ng/cm2) and RGEA (12.0 ng/cm2) released more prostacyclin than saphenous vein (4.0 ng/cm2). After AA stimulation 6-keto-prostaglandin F1 alpha release at 30 min was as follows: IMA 806.0 ng/cm2, RGEA 35.9 ng/cm2, SV 82.3 ng/cm2 (p < 0.0001 within grafts, p < 0.0001 between grafts, ANOVA for repeated measures). The internal mammary artery in comparison with the right gastroepiploic artery and saphenous vein seems to be better protected against local thrombotic events and development of coronary artery graft disease with the aid of the vasodilating and platelet inhibiting mediator prostacyclin. PMID:9618804

Bonatti, J; Dichtl, W; Dworzak, E A; Antretter, H; Unger, F; Puschendorf, B; Dapunt, O E

1998-04-01

295

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

Science.gov (United States)

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

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

2006-04-01

296

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

297

Thermohydraulic performances of the cable-in-conduit conductor for the Wendelstein 7-X magnet system  

International Nuclear Information System (INIS)

Experimental investigations were performed on pressure drop and transversal heat transfer in the cable-in-conduit conductor (CICC) for the Wendelstein 7-X magnet system. For this purpose the HELITEX test facility of KfK/ITP has been used. To evaluate the experimental results of the transversal heat transfer, a theoretical method was developed which could also be applied to other types of superconductors. The friction factor measured in the W7-X conductors is roughly three times the values in an equivalent smooth circular channel and can be well reproduced by a modified Prandtl-Karman equation. Experimental results emphasize that the transversal heat transfer between flow channel and jacket can not be described accurately either by pure heat conduction or by pure heat convection. Based on a physical mechanism, a new model was developed which considers heat conduction and heat convection simultaneously and is also applicable to other CICC's. For the W7-X conductor used equations of transversal heat transfer were derived. The thermal conductivity of the insulating layer measured in two test sections with different values of layer thickness agrees well with each other. It increases with increasing temperature and shows satisfying agreement with the data given in the literature. (orig.)

298

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

299

Trees are important conduits for emission of methane from temperate and tropical wetlands  

Science.gov (United States)

Methane produced in wetland soil generally is thought to be emitted to the atmosphere primarily via diffusion through pore water, release of gas bubbles (i.e., ebullition), and gas phase diffusion through the aerenchyma of herbaceous plants. The role of trees as a conduit for methane export from soil to the atmosphere has received limited attention despite evidence from mesocosm experiments showing that seedlings and saplings of wetland trees have a significant capacity to transport soil-produced gases. Notably ~60% of global wetlands are forested. We present in situ measurements of methane flux from a temperate carr (swamp) composed of alder (Alnus glutinosa) and birch (Betula pubescens) situated in the United Kingdom and a tropical forested peat swamp located in Borneo. The in situ data are complemented by a mesocosm experiment in which methane emissions were measured from alder saplings subjected to two water-regime treatments. In both the in situ and mesocosm studies, emissions from trees are compared to methane flux from the ground surface, the latter occurring via pore water diffusion, ebullition or the aerenchyma of herbaceous plants. We show that tree stem emissions are controlled by a number of factors including tree species, soil pore-water concentration and stem lenticel density. Our results demonstrate that the omission of tree-mediated methane fluxes from measurement campaigns conducted in forested wetland can significantly underestimate total ecosystem flux of methane.

Gauci, Vincent; Pangala, Sunitha; Gowing, David; Hornibrook, Edward

2013-04-01

300

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

Science.gov (United States)

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

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

2013-01-01

 
 
 
 
301

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

302

Normal zone propagation and thermal hydraulic quenchback in a cable-in-conduit superconductor  

Science.gov (United States)

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

Lue, J. W.; Dresner, L.

303

Normal zone propagation and thermal hydraulic quenchback in a cable-in-conduit superconductor  

International Nuclear Information System (INIS)

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

304

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

International Nuclear Information System (INIS)

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

305

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. PMID:24924784

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

2014-01-01

306

Arcuate pyroclastic conduits, ring faults, and coherent floor at Kumano caldera, southwest Honshu, Japan  

Science.gov (United States)

At the 41×23 km Miocene Kumano caldera in southwestern Japan, a large arcuate pyroclastic breccia unit is interpreted as the dissected conduit for voluminous explosive eruptions. The pyroclastic breccia and associated granite porphyry occur along the southern margin of the caldera. These rocks, collectively as much as 22 km long and 800 m wide, intrude the arcuate fault bounding the southern caldera margin. The breccia is interpreted as the vent facies of ash-flow tuff adjacent to the caldera, based on similar lithologies, phenocryst modes of juvenile clasts, and matrix character. Cataclasites along the major faults include both country rocks and pyroclastic breccia, yet some cataclasite blocks are contained within the pyroclastic breccia. These geometric and textural relations suggest that the faulting took place during caldera-forming eruption. Prevolcanic sedimentary rocks enclosed by the arcuate faults are interpreted as the dissected coherent floor of the caldera, which were subsided several hundreds to a thousand meters. No large-scale piecemeal disruption of the caldera floor is evident. Orientations of striations with the cataclasites and altitudes of the base of the tuff suggest the asymmetric trap-door subsidence of this caldera. The overall caldera geometry is the nested trap-door piston-cylinder subsidence, each 21×15 and 25×23 km in diameter, in contrast to previous interpretation of a funnel shape.

Miura, Daisuke

1999-10-01

307

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

Directory of Open Access Journals (Sweden)

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

William R. Halliday

1998-01-01

308

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

Energy Technology Data Exchange (ETDEWEB)

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.

Takahashi, Hiroyuki [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)]. E-mail: hiroyuki.takahahi.ff@hitachi.com; Kudo, Y. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan); Tsuchiya, K. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan); Kizu, K. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan); Ando, T. [Nippon Advanced Technology, 812-43 Funaishikawa, Tokai-mura, Naka-gun, Ibaraki-ken 319-1111 (Japan); Matsukawa, M. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan); Tamai, H. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan); Miura, Y. [Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)

2006-02-15

309

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)

310

Cu-vapor laser pumped 1 ns dye laser  

International Nuclear Information System (INIS)

A high repetition rate (10 kHz) short pulse dye laser pumped by Cu-vapor laser is described. The pulse duration reduction is achieved by the method of the competing cavity dye lasers (CCDL). The output pulse duration of the CCDL was 1 ns which means 25 fold shortening with respect to the pumping Cu-vapor laser pulse. The other CCDL parameters were as follows: pulse energy 0.2 ?J; repetition rate 10 kHz; wavelength 570 nm; energy fluctuation less than ±3%. (orig.)

311

Sensory recovery after primary repair of palmar digital nerves using a Revolnerv(®) collagen conduit: a prospective series of 27 cases.  

Science.gov (United States)

Despite advances in microsurgery, digital nerve repair remains a challenge due to the lack of reproducible procedures with satisfactory functional results. The aim of this study was to compare the sensory and functional results of direct microsurgical sutures protected by a Revolnerv(®) nerve regeneration conduit, with results of a series of direct sutures without a protective conduit in the literature. From November 2009 to April 2010, 35 patients were treated by direct epiperineural suture for digital nerve injury, protected by a Revolnerv(®) nerve regeneration conduit at the FESUM centre "SOS-mains Lesquin/CHRU de Lille". Sensory recovery was assessed by the static two-point discrimination Weber test (WS) and the Semmes-Weinstein (SW) test at postoperative months 1, 3, and 6. The final evaluation was performed after a minimum follow-up of 6 months. Statistical analysis of sensory results (WS and SW) was mainly performed with non-parametric tests (Wilcoxon, Mann and Whitney). PS4) discrimination at 6 months, and the average WS was 10.3 (±3.76). There was a tendency to better WS results in sharp transections compared to jagged lacerations (9.19 vs 11.82). The SW test was satisfactory in 15% of patients and acceptable in 30%. There were no complications from the Revolnerv(®) collagen tube. After 6 months follow-up this study shows that results with the Revolnerv(®) nerve regeneration conduit on direct palmar digital nerve sutures were comparable to but not better than those of uncoated direct sutures. A study including a larger population with longer follow-up is necessary to determine the value of this technique and its recommendation for general use in all digital nerve injuries. PMID:25169199

Arnaout, A; Fontaine, C; Chantelot, C

2014-09-01

312

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cable-In-Conduit conductors feature large current-carrying capacity and stability against local and transient heat deposition. As such they are suitable for application in superconducting magnets for nuclear fusion, as the ones of the International Thermonuclear Experimental Reactor (ITER). Due to the high cost connected to sample assembly and test, simulation is an essential tool for studying and optimizing the performance of CIC conductors. However, the task is made complex by the cabli...

Rolando, Gabriella

2013-01-01

313

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

314

The interior of a volcanic summit: TerraSAR-X interferometry reveals complex conduit system at Volcán de Colima, Mexico  

Science.gov (United States)

The dimensions and shape of the volcanic conduit is one of the main parameters controlling the dynamics and style volcanic eruptions and their precursors, but also one of the main unknowns. Different types of pre-eruptive signals originate from this region, such as changes in the gas composition, earthquakes, tremors and long periodic seismicity, as well as deformation on different scales, all of which strictly depend on the source geometry. However, vulnerability of near-summit stations during explosive eruptions leads to a sparse spatial resolution and hence poor a knowledge of the shallow source process and its parameters. Such incomplete observations also increase the difficulty of identifying episodes of unrest that will lead to eruption. At Volcán de Colima, Mexico, the plumbing of the shallow conduit system caused detectable and characteristic volcano deformation during the days prior to the renewal of the volcanic activity in 2013, which was initiated by an explosion. Here we present a model of the shallow conduit system at Colima, based on pre-explosive summit deformation detected in high resolution satellite radar and camera observations. The radar data are interferometrically processed to provide displacement maps up to 7 hours before the explosion, and are synthetically well reproduced using a boundary element method. This allows constraining a complex, possibly curved ascent path, with at least two hydraulically connected pressurized regions at shallow levels beneath the dome. The locations of the sources coincide with the later path of magma ascent. Our results highlight the geometrical complexity of the shallow conduit system at Colima, which can condionally become detectable when being plumbed prior to explosive eruptions. The small temporal and spatial extent of the deformation signal may explain why many volcano eruptions occur without precursory deformation activity.

Salzer, Jacqueline T.; Nikkhoo, Mehdi; Walter, Thomas R.; Reyes-Dávila, Gabriel; Bretón, Mauricio; Arambula-Mendoza, Raul

2014-05-01

315

A la découverte des troubles des conduites alimentaires lors de la maternité: regard de la sage-femme  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Contexte : Les troubles des conduites alimentaires (TCA) constituent un problème de santé actuelle au vu du culte de la minceur véhiculé par la société. En regard de ce phénomène sociétal, les remaniements psychiques et physiques de la grossesse peuvent avoir un impact sur les comportements alimentaires des femmes enceintes, plus particulièrement auprès de celles déjà préalablement concernées par les TCA. Selon nous, cette problématique n'est pas assez considérée en maternit...

Fernandes Coelho, Jessica; Riera, Lucie; Politis Mercier, Maria-pia

2013-01-01

316

46 CFR 39.20-1 - Vapor collection system-TB/ALL.  

Science.gov (United States)

...tankship must have a means to isolate the inert gas supply from the vapor collection system. The inert gas main isolation valve required by SOLAS...with hose saddles which provide adequate support to prevent kinking or collapse of...

2010-10-01

317

ACCUMULATIVE SAFETY PERIOD OF PREMISES IN THE CASE OF THEIR POLLUTION WITH TOXIC MERCURY VAPORS  

Directory of Open Access Journals (Sweden)

Full Text Available An ecological indicator is determined - accumulative period of safety in premises which means duration of the relative safety of the premises after occurrence of their pollution with mercury vapor or other toxic substances.

Tatyana Dmitrucha

2013-12-01

318

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)

319

Leaf hydraulic vulnerability is related to conduit dimensions and drought resistance across a diverse range of woody angiosperms.  

Science.gov (United States)

Hydraulic dysfunction in leaves determines key aspects of whole-plant responses to water stress; however, our understanding of the physiology of hydraulic dysfunction and its relationships to leaf structure and ecological strategy remains incomplete. Here, we studied a morphologically and ecologically diverse sample of angiosperms to test whether the water potential inducing a 50% loss in leaf hydraulic conductance (P50(leaf)) is predicted by properties of leaf xylem relating to water tension-induced conduit collapse. We also assessed the relationships between P50(leaf) and other traits considered to reflect drought resistance and ecological strategy. Across species, P50(leaf) was strongly correlated with a theoretical predictor of vulnerability to cell collapse in minor veins (the cubed ratio of the conduit wall thickness to the conduit lumen breadth). P50(leaf) was also correlated with mesophyll traits known to be related to drought resistance, but unrelated to traits associated with carbon economy. Our data indicate a link between the structural mechanics of leaf xylem and hydraulic function under water stress. Although it is possible that collapse may contribute directly to dysfunction, this relationship may also be a secondary product of vascular economics, suggesting that leaf xylem is dimensioned to avoid wall collapse. PMID:20738785

Blackman, Christopher J; Brodribb, Tim J; Jordan, Gregory J

2010-12-01

320

Beneficial effects of lifelong caloric restriction on endothelial function are greater in conduit arteries compared to cerebral resistance arteries.  

Science.gov (United States)

Endothelial dysfunction occurs in conduit and cerebral resistance arteries with advancing age. Lifelong caloric restriction (CR) can prevent the onset of age-related dysfunction in many tissues, but its effects on cerebral resistance artery function, as compared with conduit artery function, have not been determined. We measured endothelium-dependent dilation (EDD) in the carotid artery and middle cerebral artery (MCA) from young (5-7 months), old ad libitum fed (AL, 29-32 months), and old lifelong CR (CR, 40 % CR, 29-32 months) B6D2F1 mice. Compared with young, EDD for old AL was 24 % lower in the carotid and 47 % lower in the MCA (p??0.05), but was 25 % lower than young in the MCA (p?TEMPOL improved EDD for old AL (p?>?0.05), with no effect in young or old CR (p?>?0.05). In the MCA, incubation with TEMPOL or the NADPH oxidase inhibitor apocynin augmented EDD in old AL (p?conduit arteries, but only partially in cerebral resistance arteries. These benefits of lifelong CR on EDD result from lower oxidative stress and greater NO bioavailability. PMID:24065292

Walker, Ashley E; Henson, Grant D; Reihl, Kelly D; Nielson, Elizabeth I; Morgan, R Garrett; Lesniewski, Lisa A; Donato, Anthony J

2014-04-01

 
 
 
 
321

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

322

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

323

Association of T-zone reticular networks and conduits with ectopic lymphoid tissues in mice and humans.  

Science.gov (United States)

Ectopic or tertiary lymphoid tissues (TLTs) are often induced at sites of chronic inflammation. They typically contain various hematopoietic cell types, high endothelial venules, and follicular dendritic cells; and are organized in lymph node-like structures. Although fibroblastic stromal cells may play a role in TLT induction and persistence, they have remained poorly defined. Herein, we report that TLTs arising during inflammation in mice and humans in a variety of tissues (eg, pancreas, kidney, liver, and salivary gland) contain stromal cell networks consisting of podoplanin(+) T-zone fibroblastic reticular cells (TRCs), distinct from follicular dendritic cells. Similar to lymph nodes, TRCs were present throughout T-cell-rich areas and had dendritic cells associated with them. They expressed lymphotoxin (LT) ? receptor (LT?R), produced CCL21, and formed a functional conduit system. In rat insulin promoter-CXCL13-transgenic pancreas, the maintenance of TRC networks and conduits was partially dependent on LT?R and on lymphoid tissue inducer cells expressing LT?R ligands. In conclusion, TRCs and conduits are hallmarks of secondary lymphoid organs and of well-developed TLTs, in both mice and humans, and are likely to act as important scaffold and organizer cells of the T-cell-rich zone. PMID:21435450

Link, Alexander; Hardie, Debbie L; Favre, Stéphanie; Britschgi, Mirjam R; Adams, David H; Sixt, Michael; Cyster, Jason G; Buckley, Christopher D; Luther, Sanjiv A

2011-04-01

324

Vaporization thermodynamics of aluminum carbide  

Energy Technology Data Exchange (ETDEWEB)

The vapor pressure of aluminum carbide has been measured over the temperature range 1321 to 1607 K using Knudsen-effusion mass spectrometry. Vaporization occurs incongruently to give Al(g) and graphite as reaction products. The vapor pressure of aluminum above the (Al/sub 4/C/sub 3/ + C) mixture over the experimental temperature range is (R/J K/sup -1/ mol/sup -1/)1n(p/Pa) = -(3.447 +- 0).036) x 10/sup 5/(K/T) + (218.518 +- 2.470). The third-law enthalpy for the reaction: Al/sub 4/C/sub 3/(s) = 4Al(g) + 3C(s), obtained from the present vapor pressures is ..delta.. H/sup 0/(298.15 K) = (1493 +- 1) kJ mol/sup -1/. The corresponding second-law result is ..delta.. H/sup 0/(298.15 K) = (1408 +- 14) kJ mol/sup -1/. The enthalpy of formation of Al/sub 4/C/sub 3/(s) calculated from the present third-law vaporization enthalpy and the enthalpy of formation of Al(g) is ..delta.. H/sub f//sup 0/(Al/sub 4/C/sub 3/, s, 298.15 K) = -(187 +- 34) kJ mol/sup -1/.

Rinehart, G.H.; Behrens, R.G.

1980-01-01

325

Melt and vapor characteristics in an electron beam evaporator  

International Nuclear Information System (INIS)

Two different approaches have been compared for the calculation of the free surface temperature Ts in cerium or copper evaporation experiments: the first method considers properties of the melt: an empirical law is used to take into account turbulent thermal convection, instabilities and characterization of the free surface. The second method considers the vapor flow expansion and connects Ts to the measured terminal temperature and terminal mean parallel velocity of the vapor jet, by direct simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high characterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that Ts and the Knudsen number at the vapour source reach a threshold when the beam power increases. (author). 12 figs., 1 tab., 21 refs

326

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

327

Investigation of Relationship between In-Situ Stress and Fluid Conduits from Chinshui Geothermal Area, NE Taiwan  

Science.gov (United States)

Recently, underground geo-engineering has been paying more and more attention as the demand of natural resources and waste disposal dramatically increases these years, such as petroleum exploitation, geothermal energy, carbon capture and sequestration, and nuclear waste disposal. In the underground geo-engineering, knowledge of in-situ stress is essential for engineering design. Furthermore, understanding the relationship between fractures and in-situ stress is one of key information to evaluate the potential of fracture seal/conduit for such projects. In this study, we summarized the results of geothermal exploration in the ChinShui Geothermal area, NE Taiwan. The results are integrated from core observation, downhole physical logging, anelastic strain recovery, paleostress analysis, and focal mechanism stress inversion around the ChinShui geothermal area, Ilan, NE Taiwan. The in-situ stress results from multi-scale observations of core-based method, local paleostress, and regionally focal mechanisms all show strike-slip faulting stress regime of NE-compression and NW-extension as recent stress state. Using the classification of non-filling and filling (closed and opened) fractures, we are able to identify no-fluid fractures, healed fractures and fluid conduits, respectively. The fluid conduits strike NE, which is consistent with the predicted orientation of open cracks based on current stress state. Accroding to the orientation distribution of fluid conduits, the stress ratio and fluid pressure ratio are estimated as 0.30 and 0.59, respectively. Furthremore, in accordance with the tensile strength of 2.56MPa and the assumption of S2 as vertical lithostatic stress, the magnitude of S1, S3 and fluid pressure at 700m can be estimated as 21.6, 17.2 and 19.8 MPa, respectively. This study provides insights into understanding the relationship between in-situ stress state and fracture sealing/conduits. The results can be applied for geo-engineering projects such as geothermal energy exploitation, CO2 sequestration and nuclear waste disposal.

Yeh, E.; Sun, T.; Lin, S.; Lee, W.; Lin, W.; Wu, Y.; Wang, T.; Song, S.; Lin, W.

2013-12-01

328

Benzene vapor recovery and processing  

International Nuclear Information System (INIS)

The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable manner. This paper discusses various methods for collecting benzene fumes in these facilities

329

Dependence of the ac loss on the aspect ratio in a cable in conduit conductor  

International Nuclear Information System (INIS)

The coupling current loss in rectangular superconducting cables is strictly dependent on their aspect ratio, which has an impact on the area linked by the field variation and consequently on the currents induced between strands. The relation between the ac loss and aspect ratio is studied with reference to the testing of three short cable in conduit conductor (CICC) samples at the SULTAN test facility. The first conductor is a 25 kA NbTi cable for the JT60-SA tokamak; the second is a 20 kA Nb3Sn cable for the HZB hybrid magnet. The last CICC is a 68 kA Nb3Sn cable with layout similar to that of the ITER toroidal field (TF) conductor (called the 'European toroidal field (EUTF) alternate'). All the samples are assembled with two conductor sections differing only in their orientation with respect to the external variable field. In the first and third samples, the cable of one leg is rotated by 900, while in the HZB sample it is rotated by 450 with respect to the other leg. The ac loss is measured at the SULTAN test facility using a gas flow calorimetric method. A sample length of 39 cm is exposed to a sinusoidal field with an amplitude of ± 0.3 or ± 0.2 T (depending on the superconductor) and frequency variable in the range 0.1-0.8 Hz. A background field of 2 T perpendicular both to the sinusoidal field and to the sample axis is also applied. The ac loss is assessed by measuring the variation of the He enthalpy, assuming the metal enthalpy to be negligible. The loss curve for both legs is discussed in terms of the respective aspect ratios and the results, including data from former test campaigns, are compared with the aim of finding an analytical relation between the loss and the conductor dimensions.

330

Roads as conduits for exotic plant invasions in a semiarid landscape  

Science.gov (United States)

Roads are believed to be a major contributing factor to the ongoing spread of exotic plants. We examined the effect of road improvement and environmental variables on exotic and native plant diversity in roadside verges and adjacent semiarid grassland, shrubland, and woodland communities of southern Utah (U.S.A.). We measured the cover of exotic and native species in roadside verges and both the richness and cover of exotic and native species in adjacent interior communities (50 m beyond the edge of the road cut) along 42 roads stratified by level of road improvement (paved, improved surface, graded, and four-wheel-drive track). In roadside verges along paved roads, the cover of Bromus tectorum was three times as great (27%) as in verges along four-wheel-drive tracks (9%). The cover of five common exotic forb species tended to be lower in verges along four-wheel-drive tracks than in verges along more improved roads. The richness and cover of exotic species were both more than 50% greater, and the richness of native species was 30% lower, at interior sites adjacent to paved roads than at those adjacent to four-wheel-drive tracks. In addition, environmental variables relating to dominant vegetation, disturbance, and topography were significantly correlated with exotic and native species richness and cover. Improved roads can act as conduits for the invasion of adjacent ecosystems by converting natural habitats to those highly vulnerable to invasion. However, variation in dominant vegetation, soil moisture, nutrient levels, soil depth, disturbance, and topography may render interior communities differentially susceptible to invasions originating from roadside verges. Plant communities that are both physically invasible (e.g., characterized by deep or fertile soils) and disturbed appear most vulnerable. Decision-makers considering whether to build, improve, and maintain roads should take into account the potential spread of exotic plants.

Gelbard, J.L.; Belnap, J.

2003-01-01

331

Preferential flow through karst conduit under the downtown of Taebaek, Korea  

Science.gov (United States)

Hydrological features in karst have been popular and important subjects because groundwater in karst area has a high potential to be developed as a water resources and groundwater flow and solute transport through karst aquifer is somewhat different like preferential flow through solution cavern. The city Taebaek is located at the middle eastern part of Korean peninsular and composed mainly of Paleozoic limestone and Mesozoic terrestrial sedimentary rock. There are geological structures such as thrust faults and unconformity; the former could act as hydraulic barrier due to compressive stress and the latter is a weak zone in structural aspect and could act as hydraulically permeable structure when it is combined with fold or anticline of thrust fault. There is a spring named as Hwangji at the downtown of Taebaek city, which is popular touristic site as the origin of Nakdong river. The Hwangji spring is presumed to be developed by the combined acts of unconformity and anticline of thrust fault and slightly acid water containing carbon dioxide. A tracer test with fluorescent dye is performed using Hwangji spring and three private wells which are aligned approximately to the north-west direction from the Hwangji spring. A most far well of about 956 m apart is used for tracer injection and the other two wells and Hwangji spring are used for observation points. Tracer start to be detected at the Hwangji spring 2.2 days after injection. The time taken from the start of tracer detection to peak arrival was about 1.49 days. According to the arrival time of the center of mass, the groundwater flow velocity along the karst conduit can be estimated as 259 m/day which is extremely fast compared to general groundwater velocity through porous or fractured media. This value of groundwater velocity tell us the strong possibility that groundwater outflows at the Hwangji spring after a selected journey (preferential flow path) through karst solution cavern under the pavement of downtown Taebaek city.

Kim, Y.; Koh, D.; Kim, Y.; Hwang, H.; Yum, B.

2006-12-01

332

Response of Various Conduit Arteries in Tachycardia- and Volume Overload-Induced Heart Failure  

Science.gov (United States)

Although hemodynamics changes occur in heart failure (HF) and generally influence vascular function, it is not clear whether various HF models will affect the conduit vessels differentially or whether local hemodynamic forces or systemic factors are more important determinants of vascular response in HF. Here, we studied the hemodynamic changes in tachycardia or volume-overload HF swine model (created by either high rate pacing or distal abdominal aortic-vena cava fistula, respectively) on carotid, femoral, and renal arteries function and molecular expression. The ejection fraction was reduced by 50% or 30% in tachycardia or volume-overload model in four weeks, respectively. The LV end diastolic volume was increased from 65±22 to 115±78 ml in tachycardia and 67±19 to 148±68 ml in volume-overload model. Flow reversal was observed in diastolic phase in carotid artery of both models and femoral artery in volume-overload model. The endothelial function was also significantly impaired in carotid and renal arteries of tachycardia and volume-overload animals. The endothelial dysfunction was observed in femoral artery of volume-overload animals but not tachycardia animals. The adrenergic receptor-dependent contractility decreased in carotid and femoral arteries of tachycardia animals. The protein expressions of NADPH oxidase subunits increased in the three arteries and both animal models while expression of MnSOD decreased in carotid artery of tachycardia and volume-overload model. In conclusion, different HF models lead to variable arterial hemodynamic changes but similar vascular and molecular expression changes that reflect the role of both local hemodynamics as well as systemic changes in HF. PMID:25127035

Lu, Xiao; Zhang, Zhen-Du; Guo, Xiaomei; Choy, Jenny Susana; Yang, Junrong; Svendsen, Mark; Kassab, Ghassan

2014-01-01

333

Conduit magma convection of a rhyolitic magma: Constraints from cosmic-ray muon radiography of Iwodake, Satsuma-Iwojima volcano, Japan  

Science.gov (United States)

Quantitative re-evaluation of the muon radiography data obtained by Tanaka et al. (2009) was conducted to constrain conduit magma convection at the Iwodake rhyolitic cone of Satsuma-Iwojima volcano, Japan. Re-evaluation of the measurement error considering topography and fake muon counts confirms the existence of a low-density body of 300 m in diameter and with 0.9-1.0 g cm-3 at depths of 135-190 m from the summit crater floor. The low-density material is interpreted as rhyolitic magma with 60% vesicularity on average, and existence of this unstable highly vesiculated magma at shallow depth without any recent eruptive or intrusive activity is considered as evidence of conduit magma convection. The structure of the convecting magma column top was modeled based on density calculations of vesiculated ascending and outgassed descending magmas, compared with the observed density anomaly. The existence of the low-density anomaly was confirmed by comparison with published gravity measurements, and the predicted degassing at the shallow magma conduit top agrees with observed heat discharge anomaly distribution localized at the summit area. This study confirms that high viscosity of silicic magmas can be compensated by a large size conduit to cause the conduit magma convection phenomena. The rare occurrence of conduit magma convection in a rhyolitic magma system at Iwodake is suggested to be due to its specific magma features of low H2O content and high temperature.

Shinohara, Hiroshi; Tanaka, Hiroyuki K. M.

2012-10-01

334

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

335

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

Science.gov (United States)

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

Kamb, Barclay

1987-08-01

336

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.)

337

Sealed copper vapor laser tube  

Science.gov (United States)

Since copper vapor lasers were first reported in 1966, they have suffered from discharge contamination due to outgassing of materials at high temperatures. To remove impurities, a flowing buffer gas is normally used, making a vacuum and gas handling system necessary. A sealed copper vapor laser tube has been developed. Made from metal, glass and ceramic, it features permanent hard seals at electrodes and windows, making the tube rugged and allowing long shelf and operating lives. The first tube in the series, the XL7000, is still on life test and has reached over 1200 operating hours with many thermal cycles.

Clark, Graeme L.; Livingstone, Ewan S.

1994-05-01

338

Image Storage in Hot Vapors  

CERN Document Server

We theoretically investigate image propagation and storage in hot atomic vapor. A $4f$ system is adopted for imaging and an atomic vapor cell is placed over the transform plane. The Fraunhofer diffraction pattern of an object in the object plane can thus be transformed into atomic Raman coherence according to the idea of ``light storage''. We investigate how the stored diffraction pattern evolves under diffusion. Our result indicates, under appropriate conditions, that an image can be reconstructed with high fidelity. The main reason for this procedure to work is the fact that diffusion of opposite-phase components of the diffraction pattern interfere destructively.

Zhao, L; Xiao, Y; Yelin, S F

2007-01-01

339

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

340

Silicon Detectors For Helium Liquid And Vapor  

Science.gov (United States)

Simple electrical-resistance devices made of silicon indicate whether helium liquid or helium vapor present. Devices designed primarily for use in outer space, were tested and found to operate in normal Earth gravity. Silicon cubes supported by stainless-steel wires and strips. Voltage across each cube at fixed current indicates whether immersed in helium liquid or vapor. Liquid cools more than vapor does, resulting in greater electrical resistance. Such helium-liquid/vapor detectors incorporated into ducts or containers of laboratory equipment, and used to infer locations of liquid/vapor interfaces in order to measure quantities of liquid and vapor or to control refill operations.

Di Pirro, M. J.; Serlemitsos, A. T.

1990-01-01

 
 
 
 
341

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

342

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

343

Vapor generation methods for explosives detection research  

Energy Technology Data Exchange (ETDEWEB)

The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

2012-12-01

344

Passive sampler for water vapor  

Energy Technology Data Exchange (ETDEWEB)

In this preliminary study, a report is made on improvements made to a passive sampler for water vapor and on the results of tests to determine its suitability for studies of indoor air quality. Tests completed demonstrate precision, accuracy, linear response with exposure, sensitivity, and capacity sufficient for use in large scale studies to determine absolute humidities inexpensively.

Girman, J.R.; Allen, J.R.; Lee, A.Y.

1986-01-01

345

Passive sampler for water vapor  

Energy Technology Data Exchange (ETDEWEB)

In this preliminary study, we report on improvements made to a passive sampler for water vapor and on the results of tests to determine its suitability for studies of indoor air quality. Tests completed demonstrated precision, accuracy, linear response with exposure, sensitivity and capacity sufficient for use in large scale studies to determine absolute humidities inexpensively. 7 references, 3 figures.

Girman, J.R.; Allen, J.R.; Lee, A.Y.

1984-02-01

346

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

347

Vapor pressure of uranyl ?-diketonates  

International Nuclear Information System (INIS)

A flow method has been used to measure the saturated vapor pressure of uranyl dipivaloylmethanate and pivaloyltrifluoroacetonate. The UO2(DPM)2 in the gas phase is monomeric; the vapor pressure is described by the equation log p (Pa) = (9670 +/- 200)/T + (22.48 +/- 0.45), T = 413-4730K, ?H/sub l/ = (185 +/- 4) kJ/mole, ?S/sub l/ = (334 +/- 9) J/(mole x ?K); log p (Pa) = (5270 +/- 203)/T + (13.05 +/- 0.41), T = 473-5330K, ?H/sub vap/ = (101 +/- 4) kJ/mole, ?S/sub vap/ = (154 +/- 8) J/(mole x 0K). For the UO2 (PTFA)2, partial dimerization in the gas phase is assumed; the apparent vapor pressure (calculated for the monomeric state) is described by the equation log p (Pa) = (7206 +/- 115)/T + (17.15 +/- 0.33), T = 403-4830K. Within the temperature intervals studied, the UO2-(DPM)2 and UO2 (PTFA)2 have approximately the same volatility, which is considerably less than that of UO2 (HFA)2. Uranyl pivaloylacetonate and trifluoroacetylacetonate are too low in thermal stability to permit measurement of their vapor pressure

348

40 CFR 796.1950 - Vapor pressure.  

Science.gov (United States)

...situation, and thus provide a method for ranking the relative volatilities of chemicals...Vapor Density of Dieldrin,” Journal of Agricultural and Food Chemistry...Apparent Vapor Pressure of Lindane,” Journal of Agricultural and Food Chemistry,...

2010-07-01

349

Low temperature operated copper vapor laser  

International Nuclear Information System (INIS)

Experimental studies on newly developed copper vapor laser operated in hydrogen bromide gas under low temperature were successfully achieved using a conventional high temperature operated copper vapor laser tube. We present remarkable difference against conventional copper vapor laser in terms of the spatial and temporal features. This type of copper vapor laser is expected to have higher efficiency at high pulse repetition frequency and advantage in the features of laser pulse. (author)

350

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.)

351

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

Directory of Open Access Journals (Sweden)

Full Text Available In several papers, the solar cycle (SC effect in the lower atmosphere has been linked observationally to the Quasi-biennial Oscillation (QBO of the zonal circulation. Salby and Callaghan (2000 in particular analyzed the QBO wind measurements, covering more than 40 years, and discovered that they contain a large SC signature at 20 km. We present here the results from a study with our 3-D Numerical Spectral Model (NSM, which relies primarily on parameterized gravity waves (GW to describe the QBO. In our model, the period of the SC is taken to be 10 years, and the relative amplitude of radiative forcing varies exponentially with height, i.e., 0.2% at the surface, 2% at 50 km, and 20% at 100 km and above. Applying spectral analysis to identify the SC signature, the model generates a relatively large modulation of the QBO, which reproduces the observations qualitatively. The numerical results demonstrate that the QBO modulation, closely tracking the phase of the SC, is robust and persists at least for 70 years. The question is what causes the SC effect, and our analysis shows that four interlocking processes are involved: (1 In the mesosphere at around 60 km, the solar UV variations generate in the zonal winds a SC modulation of the 12-month annual oscillation, which is hemispherically symmetric and confined to equatorial latitudes like the QBO. (2 Although the amplitude of this equatorial annual oscillation (EAO is relatively small, its SC modulation is large and extends into the lower stratosphere under the influence of, and amplified by, wave forcing. (3 The amplitude modulations of both EAO and QBO are essentially in phase with the imposed SC heating for the entire time span of the model simulation. This indicates that, due to positive feedback in the wave mechanism, the EAO apparently provides the pathway and pacemaker for the SC modulation of the QBO. (4 Our analysis demonstrates that the SC modulations of the QBO and EAO are amplified by tapping the momentum from the upward propagating gravity waves. Influenced and amplified by wave processes, the QBO thus acts as conduit to transfer to lower altitudes the larger SC variations in the UV absorbed in the mesosphere. Our model produces in the temperature variations of the QBO and EAO measurable SC modulations at polar latitudes near the tropopause. The effects are apparently generated by the meridional circulation, and planetary waves presumably, which redistribute the energy from the equatorial region where the waves are very effective in amplifying the SC influence.

H. G. Mayr

2007-06-01

352

Rheology contrast in the shallow conduit and eruption dynamics at Stromboli: insights from analogue experiments  

Science.gov (United States)

Strombolian eruptions result from the bursting of large individual gas pockets (slugs) in a low-viscosity magma. Scaled experimental investigations of the processes involved have generally been carried out in single Newtonian liquids, and have explored the dynamics of slug expansion, burst and their control on the generation of geophysical signals. Such studies provide a thorough first order investigation of the mechanisms involved, but little attention has been given so far to the processes of slug expansion and burst in more complex fluids. Observations at Stromboli show that obstructions in the conduit (due to, e.g., partial wall collapse or fall back in the vent of ejecta) can generate a viscous impedance within the upper portion of magma, leading to more violent eruptions. Petrological and textural data also suggest the presence of different magma rheologies due to degassing driven crystallisation. Here we use laboratory experiments to investigate the role of a vertical contrast in magma rheology on the dynamics of slug expansion and burst, and the resulting geophysical signals. The analogue materials used are silicon oil (? = 0.1 Pa*s) capped with castor oil (? = 1 Pa*s) to give a viscosity contrast of 10. Vertical pressure gradient is scaled by reducing the pressure at the top of the experimental apparatus with a vacuum pump. Pressure variations are measured at the top and bottom of the apparatus and correlated with high-speed imagery of the experiments and the results compared with control experiments using single liquid. The thickness of the viscous plug was varied along with the gas volumes and the gas pressure at the liquid surface (1 kPa, 3 kPa and 300 Pa). Our results show that the thickness of the viscous plug strongly controls slug expansion and systematically changes the magnitude of the associated pressure transients, favouring a more impulsive and energetic pressure release compared with the control experiments. The intrusion of slugs in the viscous plug leads to complex flow configurations: small slugs can enter the viscous plug either partly or wholly before bursting. Large slugs lead to complex interaction between the two liquids: the intrusion of the low-viscosity liquid into the high-viscosity one provides a preferential pathway for the slugs. The viscous plug generates an annulus of variable thickness acting as a narrowing of the tube. Furthermore, higher gas volumes can induce both instabilities in the falling film and the disruption of the viscous annulus, clots of which are brought to the top by the slug.

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

2014-05-01

353

Pre-Eruptive Changes in Physical Conduit Dynamics Recorded in the Final Stage of Phenocryst Growth  

Science.gov (United States)

Physical changes within a volcanic conduit prior to eruption will affect the processes that immediately follow, including the explosivity and/or duration of the eruptive event. These physical changes, which may include pressurization and heating, will be recorded in crystals that continue to grow as a result of cooling or decompression-induced undercooling in the shallow subsurface. Anorthite (An) values of plagioclase feldspar will vary as a result of pressure or temperature changes, as shown through petrologic experiments on H2O-saturated magmas. Potassium, an incompatible element in plagioclase, may vary in abundance as a result of temperature changes in the magma. Secondary ion mass spectrometry (SIMS) in depth-profiling mode has revealed late-stage changes in the An content of plagioclase phenocrysts that correlate with eruptive style. Plagioclase phenocrysts were extracted from explosive (pumice flows) and effusive (block-and-ash flows) eruptive deposits at Soufrière Hills Volcano (SHV), Montserrat. Crystals from both clast and matrix material were sputtered with an O2+ primary ion beam to a total depth of 18-25 microns. Effusive crystals display very gradual changes in An, with no abrupt variations observed in most of the samples. However, some effusive samples show An increases of 10-20% in the final micron of growth, but do not display a corresponding increase in K. In the effusive crystals, K is ~1000 ppm, but may deviate to slightly higher values when An contents decrease. Explosive crystals show more dramatic An changes 10-20 microns into the crystal surface, but never exhibit the abrupt change in the final micron of growth as observed in some effusive samples. Increased An often (but not always) correlates with increased K concentrations. Optical examination of the depth-profiled crystals reveals that regions of rising An content and stable K values are apparently free of glass and mineral inclusions. Regions with lower An and higher K values appear to represent plagioclase containing quenched melt. Increases in An content, with no corresponding increase in K, appear to represent rising pressure, not temperature, within the environment. We interpret variations in the effusive crystals as oscillatory zoning with some samples displaying a final period of pressurization. We interpret abrupt An and K changes in the explosive samples as a combination of pressurization and heating events. We are currently examining other lines of evidence to constrain pressure and temperature variations within the magma immediately prior to eruption.

Genareau, K.; Clarke, A.; Hervig, R.

2006-12-01

354

Comparison of approaches to quantify arterial damping capacity from pressurization tests on mouse conduit arteries.  

Science.gov (United States)

Large conduit arteries are not purely elastic, but viscoelastic, which affects not only the mechanical behavior but also the ventricular afterload. Different hysteresis loops such as pressure-diameter, pressure-luminal cross-sectional area (LCSA), and stress-strain have been used to estimate damping capacity, which is associated with the ratio of the dissipated energy to the stored energy. Typically, linearized methods are used to calculate the damping capacity of arteries despite the fact that arteries are nonlinearly viscoelastic. The differences in the calculated damping capacity between these hysteresis loops and the most common linear and correct nonlinear methods have not been fully examined. The purpose of this study was thus to examine these differences and to determine a preferred approach for arterial damping capacity estimation. Pressurization tests were performed on mouse extralobar pulmonary and carotid arteries in their physiological pressure ranges with pressure (P) and outer diameter (OD) measured. The P-inner diameter (ID), P-stretch, P-Almansi strain, P-Green strain, P-LCSA, and stress-strain loops (including the Cauchy and Piola-Kirchhoff stresses and Almansi and Green strains) were calculated using the P-OD data and arterial geometry. Then, the damping capacity was calculated from these loops with both linear and nonlinear methods. Our results demonstrate that the linear approach provides a reasonable approximation of damping capacity for all of the loops except the Cauchy stress-Almansi strain, for which the estimate of damping capacity was significantly smaller (22 ± 8% with the nonlinear method and 31 ± 10% with the linear method). Between healthy and diseased extralobar pulmonary arteries, both methods detected significant differences. However, the estimate of damping capacity provided by the linear method was significantly smaller (27 ± 11%) than that of the nonlinear method. We conclude that all loops except the Cauchy stress-Almansi strain loop can be used to estimate artery wall damping capacity in the physiological pressure range and the nonlinear method is recommended over the linear method. PMID:24231965

Tian, Lian; Wang, Zhijie; Lakes, Roderic S; Chesler, Naomi C

2013-05-01

355

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

Scientific Electronic Library Online (English)

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

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

2005-03-01

356

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

Scientific Electronic Library Online (English)

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

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

357

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

358

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

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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

359

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

360

40 CFR 796.1950 - Vapor pressure.  

Science.gov (United States)

...2010-07-01 2010-07-01 true Vapor pressure. 796.1950 Section 796.1950...Chemical Properties § 796.1950 Vapor pressure. (a) Introduction —(1) Background...of a chemical, depends upon the vapor pressure of chemical and on...

2010-07-01

 
 
 
 
361

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

362

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.

363

A New Role for the HTLV-1 p8 Protein: Increasing Intercellular Conduits and Viral Cell-to-Cell Transmission  

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Full Text Available Retroviruses like HIV-1 and HTLV-1 can be transmitted efficiently by direct contact between infected and target cells. For HIV-1, various modes of cell-to-cell transfer have been reported, including virological synapses, polysynapses, filopodial bridges, and nanotube-like structures. So far, only synapses and biofilms have been described for HTLV-1 transmission. Recently, Van Prooyen et al. [1] identified an additional mode of HTLV-1 transmission through cellular conduits induced by the viral accessory protein p8.

Olivier Schwartz

2011-03-01

364

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

Science.gov (United States)

A 73-year-old female with sick sinus syndrome and atrial fibrillation was implanted with a ventricular demand inhibit pacemaker. She subsequently developed multiple episodes of skin irritation and necrosis. Skin patch testing revealed sensitivity to almost every component of the pacemaker system. The pacemaker was removed and replaced with a new pacemaker in which the generator was covered with a polytetrafluoroethylene (PTFE) sheet and the lead was covered with PTFE conduit. The patient suffered no further episodes of pacemaker-associated contact dermatitis. PMID:24899091

Taguchi, Takahiro; Maeba, Satoru; Sueda, Taijiro

2014-09-01

365

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

International Nuclear Information System (INIS)

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

366

Comparasion of granisetron and metoclopramide for prevention of nausea and vomiting following total cystectomy and ileal conduit  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to examine the use of granisetron in actual clinical practice and to compare effect of dose of 1 mg granisetron after total cystectomy plus ileal conduit with group of patients which received metoclopramide. Granisetron established total control of PONV in 93,33% patients. Granisetron is 40% more effective in PONV control than metoclopramide. Only minimal nausea episodes were observed in early postoperative period in patients who had received low dose of granisetron (1 mg i.v.. .

Argirovi? R.

2007-01-01

367

33 CFR 154.826 - Vapor compressors and blowers.  

Science.gov (United States)

...Control Systems § 154.826 Vapor compressors and blowers. (a) Each inlet and outlet to a compressor or blower which handles vapor that... (b) If a reciprocating or screw-type compressor handles vapor in the vapor...

2010-07-01