40 CFR 89.414 - Air flow measurement specifications.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method...

40 CFR 89.414 - Air flow measurement specifications.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method...

40 CFR 89.414 - Air flow measurement specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method...

40 CFR 89.414 - Air flow measurement specifications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method...

40 CFR 89.415 - Fuel flow measurement specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement specifications. 89.415 Section 89.415 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.415 Fuel flow measurement specifications. The fuel flow rate measurement...

40 CFR 90.417 - Fuel flow measurement specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement specifications. 90.417 Section 90.417 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Gaseous Exhaust Test Procedures § 90.417 Fuel flow measurement specifications. (a) Fuel flow measurement...

Shuttle filter study. Volume 3: Appendix

NASA Technical Reports Server (NTRS)

1974-01-01

Test data obtained from flow resistance and contaminant tolerance tests on the various porous media evaluated in the different fluids are presented in both graphical and tabular forms. Test procedures for both flow resistance and contaminant tolerance testing are presented, and the development of a system for continuously adding contaminant at a predetermined rate to a flowing fluid stream is described. Also included is a section describing the development effort of the self-indexing filter. This concept was adapted during this program for various shuttle applications.

Particle Streak Velocimetry of Supersonic Nozzle Flows

NASA Technical Reports Server (NTRS)

Willits, J. D.; Pourpoint, T. L.

2016-01-01

A novel velocimetry technique to probe the exhaust flow of a laboratory scale combustor is being developed. The technique combines the advantages of standard particle velocimetry techniques and the ultra-fast imaging capabilities of a streak camera to probe high speed flows near continuously with improved spatial and velocity resolution. This "Particle Streak Velocimetry" technique tracks laser illuminated seed particles at up to 236 picosecond temporal resolution allowing time-resolved measurement of one-dimensional flows exceeding 2000 m/s as are found in rocket nozzles and many other applications. Developmental tests with cold nitrogen have been performed to validate and troubleshoot the technique with supersonic flows of much lower velocity and without background noise due to combusting flow. Flow velocities on the order of 500 m/s have been probed with titanium dioxide particles and a continuous-wave laser diode. Single frame images containing multiple streaks are analyzed to find the average slope of all incident particles corresponding to the centerline axial flow velocity. Long term objectives for these tests are correlation of specific impulse to theoretical combustion predictions and direct comparisons between candidate green fuels and the industry standard, monomethylhydrazine, each tested under identical conditions.

40 CFR 89.414 - Air flow measurement specifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method used...

Circulation system for flowing uranium hexafluoride cavity reactor experiments

NASA Technical Reports Server (NTRS)

Jaminet, J. F.; Kendall, J. S.

1976-01-01

Research related to determining the feasibility of producing continuous power from fissile fuel in the gaseous state is presented. The development of three laboratory-scale flow systems for handling gaseous UF6 at temperatures up to 500 K, pressure up to approximately 40 atm, and continuous flow rates up to approximately 50g/s is presented. A UF6 handling system fabricated for static critical tests currently being conducted is described. The system was designed to supply UF6 to a double-walled aluminum core canister assembly at temperatures between 300 K and 400 K and pressure up to 4 atm. A second UF6 handling system designed to provide a circulating flow of up to 50g/s of gaseous UF6 in a closed-loop through a double-walled aluminum core canister with controlled temperature and pressure is described. Data from flow tests using UF6 and UF6/He mixtures with this system at flow rates up to approximately 12g/s and pressure up to 4 atm are presented. A third UF6 handling system fabricated to provide a continuous flow of UF6 at flow rates up to 5g/s and at pressures up to 40 atm for use in rf-heated, uranium plasma confinement experiments is described.

Acute toxicities of toxaphene and endrin to larvae of seven species of amphibians

USGS Publications Warehouse

Hall, R.J.; Swineford, D.M.

1981-01-01

Seven species of amphibian larvae were exposed to toxaphene and endrin in a continuous-flow dosing system to determine differences in sensitivity to the two compounds, EC50 and LC50 estimates varied from those for Rana sphenocephala by no more than one order of magnitude when calculated on the basis of intended concentrations. Removal of pesticides from water by the test animals was significant and it makes interpretation of results difficult. Continuous-flow toxicity tests conflict with the adaptations of amphibian larvae for static water; use of such tests for amphibians requires further evaluation.

OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristie Cooper; Gary Pickrell; Anbo Wang

2003-04-01

This report summarizes technical progress over the fourth year of the ''Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery'' program, funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. During the reporting period, research efforts under the program were focused on the development and evaluation of the fiber optic flow sensor system, and field testing in Tulsa, OK and the second field test of the pressure and temperature sensors in Coalinga, CA. The feasibilitymore » of a self-compensating fiber optic flow sensor based on a cantilever beam and interferometer for real-time flow rate measurements in the fluid filled pipes of oil field was clearly demonstrated. In addition, field testing of the pressure and temperature sensors deployed downhole continued. These accomplishments are summarized here: (1) Theoretical analysis and simulations were performed to ensure performance of the design. (2) The sensor fabrication and packaging techniques were investigated and improved. (3) Prototype flow sensors were fabricated based on the fabrication experience of hundreds of test sensors. (4) A lab-scale flow testing system was constructed and used for sensor evaluation. (5) Field-testing was performed in both the indoor and outdoor flow testing facility at the University of Tulsa, OK. (6) Testing of a multimode white light pressure and temperature sensor system continued at the oil site of Chevron/Texaco Company (Coalinga CA).« less

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, C.V.; Wise, M.B.

1997-07-08

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid. 3 figs.

Atomizing, continuous, water monitoring module

DOEpatents

Thompson, Cyril V.; Wise, Marcus B.

1997-01-01

A system for continuously analyzing volatile constituents of a liquid is described. The system contains a pump for continuously pumping the liquid to be tested at a predetermined flow rate into an extracting container through a liquid directing tube having an orifice at one end and positioned to direct the liquid into the extracting container at a flow rate sufficient to atomize the liquid within the extracting container. A continuous supply of helium carrier gas at a predetermined flow rate is directed through a tube into the extracting container and co-mingled with the atomized liquid to extract the volatile constituents contained within the atomized liquid. The helium containing the extracted volatile constituents flows out of the extracting container into a mass spectrometer for an analysis of the volatile constituents of the liquid.

40 CFR 1065.545 - Verification of proportional flow control for batch sampling.

Code of Federal Regulations, 2014 CFR

2014-07-01

... control for batch sampling. 1065.545 Section 1065.545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.545 Verification of proportional flow control for batch sampling. For any...

Predevelopment Water-Level Contours for Aquifers in the Rainier Mesa and Shoshone Mountain area of the Nevada Test Site, Nye County, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph M. Fenelon; Randell J. Laczniak; and Keith J. Halford

2008-06-24

Contaminants introduced into the subsurface of the Nevada Test Site at Rainier Mesa and Shoshone Mountain by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. Although contaminants were introduced into low-permeability rocks above the regional flow system, the potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by ground-water transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the water-level distribution within each of the major aquifersmore » underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. The contoured water-level distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped, presented, and discussed in general terms as being one of three aquifer types—volcanic aquifer, upper carbonate aquifer, or lower carbonate aquifer. Each of these aquifer types was subdivided and mapped as independent continuous and isolated aquifers, based on the continuity of its component rock. Ground-water flow directions, as related to the transport of test-generated contaminants, were developed from water-level contours and are presented and discussed for each of the continuous aquifers. Contoured water-level altitudes vary across the study area and range from more than 5,000 feet in the volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,450 feet in the lower carbonate aquifer in the southern part of the study area. Variations in water-level altitudes within any single continuous aquifer range from a few hundred feet in a lower carbonate aquifer to just more than 1,100 feet in a volcanic aquifer. Flow directions throughout the study area are dominantly southward with minor eastward or westward deviations. Primary exceptions are westward flow in the northern part of the volcanic aquifer and eastward flow in the eastern part of the lower carbonate aquifer. Northward flow in the upper and lower carbonate aquifers in the northern part of the study area is possible but cannot be substantiated because data are lacking. Interflow between continuous aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form the regional ground-water flow system. The implications of these tributary flow paths in controlling transport away from the underground test areas at Rainier Mesa and Shoshone Mountain are discussed. The obvious data gaps contributing to uncertainties in the delineation of aquifers and development of water-level contours are identified and evaluated.« less

Predevelopment Water-Level Contours for Aquifers in the Rainier Mesa and Shoshone Mountain area of the Nevada Test Site, Nye County, Nevada

USGS Publications Warehouse

Fenelon, Joseph M.; Laczniak, Randell J.; Halford, Keith J.

2008-01-01

Contaminants introduced into the subsurface of the Nevada Test Site at Rainier Mesa and Shoshone Mountain by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. Although contaminants were introduced into low-permeability rocks above the regional flow system, the potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by ground-water transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the water-level distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. The contoured water-level distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped, presented, and discussed in general terms as being one of three aquifer types?volcanic aquifer, upper carbonate aquifer, or lower carbonate aquifer. Each of these aquifer types was subdivided and mapped as independent continuous and isolated aquifers, based on the continuity of its component rock. Ground-water flow directions, as related to the transport of test-generated contaminants, were developed from water-level contours and are presented and discussed for each of the continuous aquifers. Contoured water-level altitudes vary across the study area and range from more than 5,000 feet in the volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,450 feet in the lower carbonate aquifer in the southern part of the study area. Variations in water-level altitudes within any single continuous aquifer range from a few hundred feet in a lower carbonate aquifer to just more than 1,100 feet in a volcanic aquifer. Flow directions throughout the study area are dominantly southward with minor eastward or westward deviations. Primary exceptions are westward flow in the northern part of the volcanic aquifer and eastward flow in the eastern part of the lower carbonate aquifer. Northward flow in the upper and lower carbonate aquifers in the northern part of the study area is possible but cannot be substantiated because data are lacking. Interflow between continuous aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form the regional ground-water flow system. The implications of these tributary flow paths in controlling transport away from the underground test areas at Rainier Mesa and Shoshone Mountain are discussed. The obvious data gaps contributing to uncertainties in the delineation of aquifers and development of water-level contours are identified and evaluated.

Continuous-flow automation and hemolysis index: a crucial combination.

PubMed

Lippi, Giuseppe; Plebani, Mario

2013-04-01

A paradigm shift has occurred in the role and organization of laboratory diagnostics over the past decades, wherein consolidation or networking of small laboratories into larger factories and point-of-care testing have simultaneously evolved and now seem to favorably coexist. There is now evidence, however, that the growing implementation of continuous-flow automation, especially in closed systems, has not eased the identification of hemolyzed specimens since the integration of preanalytical and analytical workstations would hide them from visual scrutiny, with an inherent risk that unreliable test results may be released to the stakeholders. Along with other technical breakthroughs, the new generation of laboratory instrumentation is increasingly equipped with systems that can systematically and automatically be tested for a broad series of interferences, the so-called serum indices, which also include the hemolysis index. The routine implementation of these technical tools in clinical laboratories equipped with continuous-flow automation carries several advantages and some drawbacks that are discussed in this article.

Task Order 7. Use of activated carbon for treatment of explosives-contaminated groundwater at the Milan Army Ammunition Plant (MAAP). Final report, Apr 89-May 90

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, R.M.; Wujcik, W.J.; Lowe, W.L.

1990-05-01

The primary objective of this task was to determine the feasibility of using GAC to treat ground water contaminated by explosives at the Milan Army Ammunition Plant (MAAP) in Milan, Tennessee. Laboratory GAC isotherm studies were conducted and two carbons, Atochem, Inc. GAC 830 and Calgon Filtrasorb 300, were selected for further testing in continuous flow GAC columns. Three pilot scale continuous flow GAC column tests were performed at MAAP using the two carbons selected from the laboratory GAC isotherm studies. The results from the laboratory and pilot studies are presented in this report. They show that concurrent removal ofmore » explosives such as TNT, RDX, HMX, Tetryl, and nitrobenzenes from ground water using continuous flow granular activated carbon is feasible.« less

Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, D.D.; Collins, J.L.

One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test usingmore » the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required.« less

Mathematical Models of Continuous Flow Electrophoresis

NASA Technical Reports Server (NTRS)

Saville, D. A.; Snyder, R. S.

1985-01-01

Development of high resolution continuous flow electrophoresis devices ultimately requires comprehensive understanding of the ways various phenomena and processes facilitate or hinder separation. A comprehensive model of the actual three dimensional flow, temperature and electric fields was developed to provide guidance in the design of electrophoresis chambers for specific tasks and means of interpreting test data on a given chamber. Part of the process of model development includes experimental and theoretical studies of hydrodynamic stability. This is necessary to understand the origin of mixing flows observed with wide gap gravitational effects. To insure that the model accurately reflects the flow field and particle motion requires extensive experimental work. Another part of the investigation is concerned with the behavior of concentrated sample suspensions with regard to sample stream stability particle-particle interactions which might affect separation in an electric field, especially at high field strengths. Mathematical models will be developed and tested to establish the roles of the various interactions.

A perspective of laminar-flow control. [aircraft energy efficiency program

NASA Technical Reports Server (NTRS)

Braslow, A. L.; Muraca, R. J.

1978-01-01

A historical review of the development of laminar flow control technology is presented with reference to active laminar boundary-layer control through suction, the use of multiple suction slots, wind-tunnel tests, continuous suction, and spanwise contamination. The ACEE laminar flow control program is outlined noting the development of three-dimensional boundary-layer codes, cruise-noise prediction techniques, airfoil development, and leading-edge region cleaning. Attention is given to glove flight tests and the fabrication and testing of wing box designs.

Polystyrene latex separations by continuous flow electrophoresis on the Space Shuttle

NASA Technical Reports Server (NTRS)

Snyder, R. S.; Rhodes, P. H.; Miller, T. Y.; Micale, F. J.; Mann, R. V.

1986-01-01

The seventh mission of the Space Shuttle carried two NASA experiments in the McDonnell Douglas Astronautics Corporation continuous flow electrophoresis system. The objectives were to test the operation of continuous flow electrophoresis in a reduced gravity environment using stable particles with established electrokinetic properties and specifically to evaluate the influence of the electrical properties of the sample constituents on the resolution of the continuous flow electrophoretic device. Polystrene latex microspheres dispersed in a solution with three times the electrical conductivity of the curtain buffer separated with a significantly larger band spread compared to the second experiment under matched conductivity conditions. It is proposed that the sample of higher electrical conductivity distorted the electric field near the sample stream so that the polystyrene latex particles migrated toward the chamber walls where electroosmosis retarded and spread the sample.

40 CFR 1065.225 - Intake-air flow meter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225 Intake-air...

40 CFR 1065.225 - Intake-air flow meter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225 Intake-air...

40 CFR 1065.225 - Intake-air flow meter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.225 Intake-air...

A dynamic response model for pressure sensors in continuum and high Knudsen number flows with large temperature gradients

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Petersen, Brian J.; Scott, David D.

1996-01-01

This paper develops a dynamic model for pressure sensors in continuum and rarefied flows with longitudinal temperature gradients. The model was developed from the unsteady Navier-Stokes momentum, energy, and continuity equations and was linearized using small perturbations. The energy equation was decoupled from momentum and continuity assuming a polytropic flow process. Rarefied flow conditions were accounted for using a slip flow boundary condition at the tubing wall. The equations were radially averaged and solved assuming gas properties remain constant along a small tubing element. This fundamental solution was used as a building block for arbitrary geometries where fluid properties may also vary longitudinally in the tube. The problem was solved recursively starting at the transducer and working upstream in the tube. Dynamic frequency response tests were performed for continuum flow conditions in the presence of temperature gradients. These tests validated the recursive formulation of the model. Model steady-state behavior was analyzed using the final value theorem. Tests were performed for rarefied flow conditions and compared to the model steady-state response to evaluate the regime of applicability. Model comparisons were excellent for Knudsen numbers up to 0.6. Beyond this point, molecular affects caused model analyses to become inaccurate.

Studies with sample conductivity, insertion rates, and particle deflection in a continuous flow electrophoresis system

NASA Technical Reports Server (NTRS)

Williams, G., Jr.

1982-01-01

The continuous flow electrophoresis system makes electrophoresis possible in a free-flowing film of aqueous electrolyte medium. The sample continuously enters the electrolyte at the top of the chamber and is subjected to the action of a lateral dc field. This divides the sample into fractions since each component has a distinctive electrophoretic mobility. Tests were made using monodisperse polystyrene latex microspheres to determine optimum sample conductivity, insertion rates and optimum electric field applications as baseline data for future STS flight experiments. Optimum sample flow rates for the selected samples were determined to be approximately 26 micro-liters/min. Experiments with samples in deionized water yielded best results and voltages in the 20 V/cm to 30 V/cm range were optimum. Deflections of formaldehyde fixed turkey and bovine erythrocytes were determined using the continuous flow electrophoresis system. The effects of particle interactions on sample resolution and migration in the chamber was also evaluated.

Salt weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures

NASA Astrophysics Data System (ADS)

Aly, Nevin; Gomez-Heras, Miguel; Hamed, Ayman; Alvarez de Buergo, Monica

2013-04-01

weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures Nevin Aly Mohamed (1), Miguel Gomez - Heras(2), Ayman Hamed Ahmed (1), and Monica Alvarez de Buergo(2). (1) Faculty of Pet. & Min. Engineering- Suez Canal University, Suez, Egypt, (2) Instituto de Geociencias (CSIC-UCM) Madrid. Spain. Limestone is one of the most frequent building stones in Egypt and is used since the time of ancient Egyptians and salt weathering is one of the main threats to its conservation. Most of the limestone used in historical monuments in Cairo is a biomicrite extracted from the Mid-Eocene Mokattam Group. During this work, cylindrical samples (2.4 cm diameter and approx. 4.8 cm length) were subjected, in a purpose-made simulation chamber, to simulated laboratory weathering tests with fixed salt concentration (10% weight NaCl solution), at different temperatures, which were kept constant throughout each test (10, 20, 30, 40 oC). During each test, salt solutions flowed continuously imbibing samples by capilarity. Humidity within the simulation chamber was reduced using silica gel to keep it low and constant to increase evaporation rate. Temperature, humidity inside the simulation chamber and samples weight were digitally monitored during each test. Results show the advantages of the proposed experimental methodology using a continuous flow of salt solutions and shed light on the effect of temperature on the dynamics of salt crystallization on and within samples. Research funded by mission sector of high education ministry, Egypt and Geomateriales S2009/MAT-1629.

DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elena A. Tselishcheva; Steven P. Antal; Michael Z. Podowski

The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overallmore » model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.« less

LSSA large area silicon sheet task continuous Czochralski process development

NASA Technical Reports Server (NTRS)

Rea, S. N.

1978-01-01

A Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a premelter to provide molten silicon flow into the primary crucible. The basic furnace is operational and several trial crystals were grown in the batch mode. Numerous premelter configurations were tested both in laboratory-scale equipment as well as in the actual furnace. The best arrangement tested to date is a vertical, cylindrical graphite heater containing small fused silicon test tube liner in which the incoming silicon is melted and flows into the primary crucible. Economic modeling of the continuous Czochralski process indicates that for 10 cm diameter crystal, 100 kg furnace runs of four or five crystals each are near-optimal. Costs tend to asymptote at the 100 kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $20/sq m exclusive of polysilicon and slicing was obtained.

Modification of the BioMedicus centrifugal pump to provide continuous irrigation for neuroendoscopy: technical note.

PubMed

Koueik, Joyce; Rocque, Brandon G; Henry, Jordan; Bragg, Taryn; Paul, Jennifer; Iskandar, Bermans J

2018-02-01

Continuous irrigation is an important adjunct for successful intraventricular endoscopy, particularly for complex cases. It allows better visualization by washing out blood and debris, improves navigation by expanding the ventricles, and assists with tissue dissection. A method of irrigation delivery using a centrifugal pump designed originally for cardiac surgery is presented. The BioMedicus centrifugal pump has the desirable ability to deliver a continuous laminar flow of fluid that excludes air from the system. A series of modifications to the pump tubing was performed to adapt it to neuroendoscopy. Equipment testing determined flow and pressure responses at various settings and simulated clinical conditions. The pump was then studied clinically in 11 endoscopy cases and eventually used in 310 surgical cases. Modifications of the pump tubing allowed for integration with different endoscopy systems. Constant flow rates were achieved with and without surgical instruments through the working ports. Optimal flow rates ranged between 30 and 100 ml/min depending on endoscope size. Intraoperative use was well tolerated with no permanent morbidity and showed consistent flow rates, minimal air accumulation, and seamless irrigation bag replacement during prolonged surgery. Although the pump is equipped with an internal safety mechanism to protect against pressure buildup when outflow obstructions occur, equipment testing revealed that flow cessation is not instantaneous enough to protect against sudden intracranial pressure elevation. A commonly available cardiac pump system was modified to provide continuous irrigation for intraventricular endoscopy. The system alleviates the problems of inconsistent flow rates, air in the irrigation lines, and delays in changing irrigation bags, thereby optimizing patient safety and surgical efficiency. Safe use of the pump requires good ventricular outflow and, clearly, sound surgical judgment.

Estimated flow-duration curves for selected ungaged sites in Kansas

USGS Publications Warehouse

Studley, S.E.

2001-01-01

Flow-duration curves for 1968-98 were estimated for 32 ungaged sites in the Missouri, Smoky Hill-Saline, Solomon, Marais des Cygnes, Walnut, Verdigris, and Neosho River Basins in Kansas. Also included from a previous report are estimated flow-duration curves for 16 ungaged sites in the Cimarron and lower Arkansas River Basins in Kansas. The method of estimation used six unique factors of flow duration: (1) mean streamflow and percentage duration of mean streamflow, (2) ratio of 1-percent-duration streamflow to mean streamflow, (3) ratio of 0.1-percent-duration streamflow to 1-percent-duration streamflow, (4) ratio of 50-percent-duration streamflow to mean streamflow, (5) percentage duration of appreciable streamflow (0.10 cubic foot per second), and (6) average slope of the flow-duration curve. These factors were previously developed from a regionalized study of flow-duration curves using streamflow data for 1921-76 from streamflow-gaging stations with drainage areas of 100 to 3,000 square miles. The method was tested on a currently (2001) measured, continuous-record streamflow-gaging station on Salt Creek near Lyndon, Kansas, with a drainage area of 111 square miles and was found to adequately estimate the computed flow-duration curve for the station. The method also was tested on a currently (2001) measured, continuous-record, streamflow-gaging station on Soldier Creek near Circleville, Kansas, with a drainage area of 49.3 square miles. The results of the test on Soldier Creek near Circleville indicated that the method could adequately estimate flow-duration curves for sites with drainage areas of less than 100 square miles. The low-flow parts of the estimated flow-duration curves were verified or revised using 137 base-flow discharge measurements made during 1999-2000 at the 32 ungaged sites that were correlated with base-flow measurements and flow-duration analyses performed at nearby, long-term, continuous-record, streamflow-gaging stations (index stations). The method did not adequately estimate the flow-duration curves for two sites in the western one-third of the State because of substantial changes in farming practices (terracing and intensive ground-water withdrawal) that were not accounted for in the two previous studies (Furness, 1959; Jordan, 1983). For these two sites, there was enough historic, continuous-streamflow record available to perform record-extension techniques correlated to their respective index stations for the development of the estimated flow-duration curves. The estimated flow-duration curves at the ungaged sites can be used for projecting future flow frequencies for assessment of total maximum daily loads (TMDLs) or other water-quality constituents, water-availability studies, and for basin-characteristic studies.

Air flow through poppet valves

NASA Technical Reports Server (NTRS)

Lewis, G W; Nutting, E M

1920-01-01

Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.

Investigation of organic matter migrating from polymeric pipes into drinking water under different flow manners.

PubMed

Zhang, Ling; Liu, Shuming; Liu, Wenjun

2014-02-01

Polymeric pipes, such as unplasticized polyvinyl chloride (uPVC) pipes, polypropylene random (PPR) pipes and polyethylene (PE) pipes are increasingly used for drinking water distribution lines. Plastic pipes may include some additives like metallic stabilizers and other antioxidants for the protection of the material during its production and use. Thus, some compounds can be released from those plastic pipes and cast a shadow on drinking water quality. This work develops a new procedure to investigate three types of polymer pipes (uPVC, PE and PPR) with respect to the migration of total organic carbon (TOC) into drinking water. The migration test was carried out in stagnant conditions with two types of migration processes, a continuous migration process and a successive migration process. These two types of migration processes are specially designed to mimic the conditions of different flow manners in drinking water pipelines, i.e., the situation of continuous stagnation with long hydraulic retention times and normal flow status with regular water renewing in drinking water networks. The experimental results showed that TOC release differed significantly with different plastic materials and under different flow manners. The order of materials with respect to the total amount of TOC migrating into drinking water was observed as PE > PPR > uPVC under both successive and continuous migration conditions. A higher amount of organic migration from PE and PPR pipes was likely to occur due to more organic antioxidants being used in pipe production. The results from the successive migration tests indicated the trend of the migration intensity of different pipe materials over time, while the results obtained from the continuous migration tests implied that under long stagnant conditions, the drinking water quality could deteriorate quickly with the consistent migration of organic compounds and the dramatic consumption of chlorine to a very low level. Higher amounts of TOC were released under the continuous migration tests.

40 CFR 1065.640 - Flow meter calibration calculations.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... 1065.640 Section 1065.640 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.640 Flow meter...: Table 2 of § 1065.640—C fCFV versus β and γ for CFV Flow Meters C fCFV β γ exh =1.385 γ dexh = γ air = 1...

40 CFR 1065.640 - Flow meter calibration calculations.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... 1065.640 Section 1065.640 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.640 Flow meter... Flow Meters C fCFV b g exh =1.385 g dexh = g air = 1.399 0.000 0.6822 0.6846 0.400 0.6857 0.6881 0.500...

40 CFR 1065.640 - Flow meter calibration calculations.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... 1065.640 Section 1065.640 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.640 Flow meter...: Table 2 of § 1065.640—C fCFV versus β and γ for CFV Flow Meters C fCFV β γ exh =1.385 γ dexh = γ air = 1...

40 CFR 1065.640 - Flow meter calibration calculations.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... 1065.640 Section 1065.640 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.640 Flow meter... Flow Meters C fCFV β γ exh =1.385 γ dexh = γ air = 1.399 0.000 0.6822 0.6846 0.400 0.6857 0.6881 0.500...

Unified approach for incompressible flows

NASA Astrophysics Data System (ADS)

Chang, Tyne-Hsien

1995-07-01

A unified approach for solving incompressible flows has been investigated in this study. The numerical CTVD (Centered Total Variation Diminishing) scheme used in this study was successfully developed by Sanders and Li for compressible flows, especially for the high speed. The CTVD scheme possesses better mathematical properties to damp out the spurious oscillations while providing high-order accuracy for high speed flows. It leads us to believe that the CTVD scheme can equally well apply to solve incompressible flows. Because of the mathematical difference between the governing equations for incompressible and compressible flows, the scheme can not directly apply to the incompressible flows. However, if one can modify the continuity equation for incompressible flows by introducing pseudo-compressibility, the governing equations for incompressible flows would have the same mathematical characters as compressible flows. The application of the algorithm to incompressible flows thus becomes feasible. In this study, the governing equations for incompressible flows comprise continuity equation and momentum equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. Thus, the CTVD schemes can be implemented. In addition, the physical and numerical boundary conditions are properly implemented by the characteristic boundary conditions. Accordingly, a CFD code has been developed for this research and is currently under testing. Flow past a circular cylinder was chosen for numerical experiments to determine the accuracy and efficiency of the code. The code has shown some promising results.

Unified approach for incompressible flows

NASA Technical Reports Server (NTRS)

Chang, Tyne-Hsien

1995-01-01

A unified approach for solving incompressible flows has been investigated in this study. The numerical CTVD (Centered Total Variation Diminishing) scheme used in this study was successfully developed by Sanders and Li for compressible flows, especially for the high speed. The CTVD scheme possesses better mathematical properties to damp out the spurious oscillations while providing high-order accuracy for high speed flows. It leads us to believe that the CTVD scheme can equally well apply to solve incompressible flows. Because of the mathematical difference between the governing equations for incompressible and compressible flows, the scheme can not directly apply to the incompressible flows. However, if one can modify the continuity equation for incompressible flows by introducing pseudo-compressibility, the governing equations for incompressible flows would have the same mathematical characters as compressible flows. The application of the algorithm to incompressible flows thus becomes feasible. In this study, the governing equations for incompressible flows comprise continuity equation and momentum equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. Thus, the CTVD schemes can be implemented. In addition, the physical and numerical boundary conditions are properly implemented by the characteristic boundary conditions. Accordingly, a CFD code has been developed for this research and is currently under testing. Flow past a circular cylinder was chosen for numerical experiments to determine the accuracy and efficiency of the code. The code has shown some promising results.

Measuring rectilinear flow within the anterior chamber in phacoemulsification procedures.

PubMed

Oki, Kotaro

2004-08-01

To measure and photograph rectilinear flow generated in an anterior chamber model during different power phases of phacoemulsification. Oki Eye Surgery Center, Tokyo, Japan. An ultrasound (US) needle was fitted to a Sovereign WhiteStar (AMO) phacoemulsification unit. The sleeved needle was inserted into a silicone test chamber filled with balanced salt solution with glutation (BSS Plus). An LV-1610 laser Doppler vibrometer (Ono-Sokki) captured and processed the velocity and displacement of vibrations on the surface of the test chamber. Measurements were processed in a CF-520 Fast Fourier Transform (FFT) analyzer with the results shown in real time on the FFT analyzer and displayed on a computer monitor using 3-dimensional software. Four US delivery modes were measured: WhiteStar DB, WhiteStar CF, continuous mode, and short-pulse mode at 6 pulses per second (pps). Flow and vacuum were set at 20 cc/min and 200 mm Hg, respectively, and US power was 20% and 50%. Schlieren photography of the fluid flow was performed with an ultra-high-speed Memrecam fx 6000 camera (NAC Image Technology). The peak vibration velocity (m/s) and displacement at the distal end of the test chamber were greatest for continuous mode, followed by short pulse (6 pps), WhiteStar DB, and WhiteStar CF, in descending order. At 20% power, the US needle generated a peak velocity of 8.64 x 10(-3) m/s in continuous mode, 7.30 x 10(-3) m/s in short-pulse mode, 5.03 x 10(-3) m/s in DB mode, and 3.74 x 10(-3) m/s in CF mode. At 50% power, the US needle generated a peak velocity of 12.8 x 10(-3) m/s in continuous mode, 10.9 x 10(-3) m/s in short-pulse mode, 8.52 x 10(-3) m/s in DB mode, and 6.37 x 10(-3) m/s in CF mode. Schlieren photography showed the greatest wave speed, intensity, and turbulence in continuous mode and the least with the WhiteStar modes. Peak vibration velocity and amplitude of displacement were less with the WhiteStar delivery modes than with continuous power or short-pulse modes. A similar reduction was seen in the rectilinear flow under Schlieren photography. Attenuation of rectilinear flow and turbulence patterns may have clinical implications for the corneal endothelium during phacoemulsification.

Compound Capillary Flows in Complex Containers: Drop Tower Test Results

NASA Astrophysics Data System (ADS)

Bolleddula, Daniel A.; Chen, Yongkang; Semerjian, Ben; Tavan, Noël; Weislogel, Mark M.

2010-10-01

Drop towers continue to provide unique capabilities to investigate capillary flow phenomena relevant to terrestrial and space-based capillary fluidics applications. In this study certain `capillary rise' flows and the value of drop tower experimental investigations are briefly reviewed. A new analytic solution for flows along planar interior edges is presented. A selection of test cell geometries are then discussed where compound capillary flows occur spontaneously and simultaneously over local and global length scales. Sample experimental results are provided. Tertiary experiments on a family of asymmetric geometries that isolate the global component of such flows are then presented along with a qualitative analysis that may be used to either avoid or exploit such flows. The latter may also serve as a design tool with which to assess the impact of inadvertent container asymmetry.

Vertical flow chemical detection portal

DOEpatents

Linker, K.L.; Hannum, D.W.; Conrad, F.J.

1999-06-22

A portal apparatus is described for screening objects or persons for the presence of trace amounts of chemical substances such as illicit drugs or explosives. The apparatus has a test space, in which a person may stand, defined by two generally upright sides spanned by a horizontal transom. One or more fans in the transom generate a downward air flow (uni-directional) within the test space. The air flows downwardly from a high pressure upper zone, past the object or person to be screened. Air moving past the object dislodges from the surface thereof both volatile and nonvolatile particles of the target substance. The particles are entrained into the air flow which continues flowing downward to a lower zone of reduced pressure, where the particle-bearing air stream is directed out of the test space and toward preconcentrator and detection components. The sides of the portal are specially configured to partially contain and maintain the air flow. 3 figs.

Vertical flow chemical detection portal

DOEpatents

Linker, Kevin L.; Hannum, David W.; Conrad, Frank James

1999-01-01

A portal apparatus for screening objects or persons for the presence of trace amounts of chemical substances such as illicit drugs or explosives. The apparatus has a test space, in which a person may stand, defined by two generally upright sides spanned by a horizontal transom. One or more fans in the transom generate a downward air flow (uni-directional) within the test space. The air flows downwardly from a high pressure upper zone, past the object or person to be screened. Air moving past the object dislodges from the surface thereof both volatile and nonvolatile particles of the target substance. The particles are entrained into the air flow which continues flowing downward to a lower zone of reduced pressure, where the particle-bearing air stream is directed out of the test space and toward preconcentrator and detection components. The sides of the portal are specially configured to partially contain and maintain the air flow.

Flow Visualization of Liquid Hydrogen Line Chilldown Tests

NASA Technical Reports Server (NTRS)

Rame, Enrique; Hartwig, Jason W.; McQuillen John B.

2014-01-01

We present experimental measurements of wall and fluid temperature during chill-down tests of a warm cryogenic line with liquid hydrogen. Synchronized video and fluid temperature measurements are used to interpret stream temperature profiles versus time. When cold liquid hydrogen starts to flow into the warm line, a sequence of flow regimes, spanning from all-vapor at the outset to bubbly with continuum liquid at the end can be observed at a location far downstream of the cold inlet. In this paper we propose interpretations to the observed flow regimes and fluid temperature histories for two chilldown methods, viz. trickle (i.e. continuous) flow and pulse flow. Calculations of heat flux from the wall to the fluid versus wall temperature indicate the presence of the transition/nucleate boiling regimes only. The present tests, run at typical Reynolds numbers of approx O(10 (exp 5)), are in sharp contrast to similar tests conducted at lower Reynolds numbers where a well-defined film boiling region is observed.

[Responses of sap flow to natural rainfall and continuous drought of tree species growing on bedrock outcrops].

PubMed

Zhang, Hui Ling; Ding, Ya Li; Chen, Hong Song; Wang, Ke Lin; Nie, Yun Peng

2018-04-01

This study focused on bedrock outcrops, a very common habitat in karst region of southwest China. To reveal the responses of plant transpiration to natural rainfall and continuous drought, two tree species typical to this habitat, Radermachera sinica and Triadica rotundifolia, were selected as test materials. A rainout shelter was used to simulate continuous drought. The sap flow dynamics were monitored using the method of Granier's thermal dissipation probe (TDP). Our results showed that sap flow density increased to different degrees after rain in different stages of the growing season. Sap flow density of the deciduous species T. rotundifolia was always higher than that of the semi-deciduous species R. sinica. After two months without rainfall input, both species exhibited no obvious decrease in sap flow density, indicating that rainfall was not the dominant source for their water uptake, at least in the short-term. Based on the regression relationships between sap flow density and meteorological factors before and after rainfall, as well as at different stages of continuous drought, we found that the dynamics of meteorological factors contributed little to plant transpiration. The basic transpiration characteristics of both species were not changed in the circumstance of natural rainfall and short-term continuous drought, which would be closely related to the special water storage environments of bedrock outcrops and the reliance on deep water sources by tree species.

Location of acoustic emission sources generated by air flow

PubMed

Kosel; Grabec; Muzic

2000-03-01

The location of continuous acoustic emission sources is a difficult problem of non-destructive testing. This article describes one-dimensional location of continuous acoustic emission sources by using an intelligent locator. The intelligent locator solves a location problem based on learning from examples. To verify whether continuous acoustic emission caused by leakage air flow can be located accurately by the intelligent locator, an experiment on a thin aluminum band was performed. Results show that it is possible to determine an accurate location by using a combination of a cross-correlation function with an appropriate bandpass filter. By using this combination, discrete and continuous acoustic emission sources can be located by using discrete acoustic emission sources for locator learning.

Reservoir response to thermal and high-pressure well stimulation efforts at Raft River, Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plummer, Mitchell; Bradford, Jacob; Moore, Joseph

An injection stimulation test begun at the Raft River geothermal reservoir in June, 2013 has produced a wealth of data describing well and reservoir response via high-resolution temperature logging and distributed temperature sensing, seismic monitoring, periodic borehole televiewer logging, periodic stepped flow rate tests and tracer injections before and after stimulation efforts. One of the primary measures of response to the stimulation is the relationship between fluid pressure and flow rate, short-term during forced flow rate changes and the long-term change in injectivity. In this paper we examine that hydraulic response using standard pumping test analysis methods, largely because pressuremore » response to the stimulation was not detected, or measurable, in other wells. Analysis of stepped rate flow tests supports the inference from other data that a large fracture, with a radial extent of one to several meters, intersects the well in the target reservoir, suggests that the flow regime is radial to a distance of only several meters and demonstrates that the pressure build-up cone reaches an effective constant head at that distance. The well’s longer term hydraulic response demonstrated continually increasing injectivity but at a dramatically faster rate later from ~2 years out and continuing to the present. The net change in injectivity is significantly greater than observed in other longterm injectivity monitoring studies, with an approximately 150–fold increase occurring over ~2.5 years. While gradually increasing injectivity is a likely consequence of slow migration of a cooling front, and consequent dilation of fractures, the steady, ongoing, rate of increase is contrary to what would be expected in a radial or linear flow regime, where the cooling front would slow with time. As a result, occasional step-like changes in injectivity, immediately following high-flow rate tests suggest that hydro shearing during high-pressure testing altered the near-well permeability structure.« less

40 CFR 1065.602 - Statistics.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... number of degrees of freedom, ν, as follows, noting that the εi are the errors (e.g., differences... a gas concentration is measured continuously from the raw exhaust of an engine, its flow-weighted...

40 CFR 1065.280 - Paramagnetic and magnetopneumatic O2 detection analyzers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments O2 Measurements § 1065... diluted exhaust for batch or continuous sampling. You may use O2 measurements with intake air or fuel flow.... 15, 2011] Air-to-Fuel Ratio Measurements ...

40 CFR 1065.280 - Paramagnetic and magnetopneumatic O2 detection analyzers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments O2 Measurements § 1065... diluted exhaust for batch or continuous sampling. You may use O2 measurements with intake air or fuel flow.... 15, 2011] Air-to-Fuel Ratio Measurements ...

40 CFR 80.165 - Certification test procedures and standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Detergent Gasoline § 80.165 Certification test... additive is mixed in a test fuel meeting all relevant requirements of § 80.164, including the deposit... control testing. The required test fuel must produce no more than 5% flow restriction in any one injector...

Simulant Gas Test Technique Feasibility

DTIC Science & Technology

1990-05-01

DY’NAMICS LABORATORY WRIGHT RESEARCH AND DEVELOPMENT CENTER AIR FORCE SYSTEMS COMMAND WRIGHT-PATTERSON AIR FORCE BASE, OHIO 45433-6553 NOTIr’ When...TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Hypersonic-test Air -chemistry Non-equilibrium-flow 0g...ABSTRACT (Continue on reverse if necessary and identify by block number) ’[lie Ulcertaillty engendered by non-equilibrium air effects on hypersonic

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions

PubMed Central

Ramos-Ruiz, Adriana; Wilkening, Jean V.; Field, James A.; Sierra-Alvarez, Reyes

2017-01-01

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30 days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1 mg L-1), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005 mg L-1). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. PMID:28472709

Continuous field-flow separation of particle populations in a dielectrophoretic chip with three dimensional electrodes

NASA Astrophysics Data System (ADS)

Iliescu, Ciprian; Tresset, Guillaume; Xu, Guolin

2007-06-01

This letter presents a dielectrophoretic (DEP) separation method of particles under continuous flow. The method consists of flowing two particle populations through a microfluidic channel, in which the vertical walls are the electrodes of the DEP device. The irregular shape of the electrodes generates both electric field and fluid velocity gradients. As a result, the particles that exhibit negative DEP can be trapped in the fluidic dead zones, while the particles that experience positive DEP are concentrated in the regions with high velocity and collected at the outlet. The device was tested with dead and living yeast cells.

40 CFR 63.7833 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Code of Federal Regulations, 2014 CFR

2014-07-01

... scrubber water flow rate is below the operating limits, you must follow the corrective action procedures in... compound emissions for each operating day according to the performance test procedures in § 63.7824(e); (ii... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

40 CFR 63.7833 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Code of Federal Regulations, 2012 CFR

2012-07-01

... scrubber water flow rate is below the operating limits, you must follow the corrective action procedures in... compound emissions for each operating day according to the performance test procedures in § 63.7824(e); (ii... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

40 CFR 63.7833 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Code of Federal Regulations, 2013 CFR

2013-07-01

... scrubber water flow rate is below the operating limits, you must follow the corrective action procedures in... compound emissions for each operating day according to the performance test procedures in § 63.7824(e); (ii... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

40 CFR 63.7833 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Code of Federal Regulations, 2011 CFR

2011-07-01

... scrubber water flow rate is below the operating limits, you must follow the corrective action procedures in... compound emissions for each operating day according to the performance test procedures in § 63.7824(e); (ii... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

40 CFR 1065.202 - Data updating, recording, and control.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... 1065.202 Section 1065.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments § 1065.202 Data updating, recording...; § 1065.545 Intake-air or raw-exhaust flow rate 1 Hz means. § 1065.530; § 1065.545 Dilution air flow if...

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642 SSV...

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642 SSV...

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642 SSV...

40 CFR 1065.642 - SSV, CFV, and PDP molar flow rate calculations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false SSV, CFV, and PDP molar flow rate calculations. 1065.642 Section 1065.642 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.642 SSV...

Highlights of the high-temperature falling particle receiver project: 2012 - 2016

NASA Astrophysics Data System (ADS)

Ho, C. K.; Christian, J.; Yellowhair, J.; Jeter, S.; Golob, M.; Nguyen, C.; Repole, K.; Abdel-Khalik, S.; Siegel, N.; Al-Ansary, H.; El-Leathy, A.; Gobereit, B.

2017-06-01

A 1 MWt continuously recirculating falling particle receiver has been demonstrated at Sandia National Laboratories. Free-fall and obstructed-flow receiver designs were tested with particle mass flow rates of ˜1 - 7 kg/s and average irradiances up to 1,000 suns. Average particle outlet temperatures exceeded 700 °C for the free-fall tests and reached nearly 800 °C for the obstructed-flow tests, with peak particle temperatures exceeding 900 °C. High particle heating rates of ˜50 to 200 °C per meter of illuminated drop length were achieved for the free-fall tests with mass flow rates ranging from 1 - 7 kg/s and for average irradiances up to ˜ 700 kW/m2. Higher temperatures were achieved at the lower particle mass flow rates due to less shading. The obstructed-flow design yielded particle heating rates over 300 °C per meter of illuminated drop length for mass flow rates of 1 - 3 kg/s for irradiances up to ˜1,000 kW/m2. The thermal efficiency was determined to be ˜60 - 70% for the free-falling particle tests and up to ˜80% for the obstructed-flow tests. Challenges encountered during the tests include particle attrition and particle loss through the aperture, reduced particle mass flow rates at high temperatures due to slot aperture narrowing and increased friction, and deterioration of the obstructed-flow structures due to wear and oxidation. Computational models were validated using the test data and will be used in future studies to design receiver configurations that can increase the thermal efficiency.

Analysis of Developing Gas/liquid Two-Phase Flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elena A. Tselishcheva; Michael Z. Podowski; Steven P. Antal

The goal of this work is to develop a mechanistically based CFD model that can be used to simulate process equipment operating in the churn-turbulent regime. The simulations were performed using a state-of-the-art computational multiphase fluid dynamics code, NPHASE–CMFD [Antal et al,2000]. A complete four-field model, including the continuous liquid field and three dispersed gas fields representing bubbles of different sizes, was first carefully tested for numerical convergence and accuracy, and then used to reproduce the experimental results from the TOPFLOW test facility at Forschungszentrum Dresden-Rossendorf e.V. Institute of Safety Research [Prasser et al,2007]. Good progress has been made inmore » simulating the churn-turbulent flows and comparison the NPHASE-CMFD simulations with TOPFLOW experimental data. The main objective of the paper is to demonstrate capability to predict the evolution of adiabatic churn-turbulent gas/liquid flows. The proposed modelling concept uses transport equations for the continuous liquid field and for dispersed bubble fields [Tselishcheva et al, 2009]. Along with closure laws based on interaction between bubbles and continuous liquid, the effect of height on air density has been included in the model. The figure below presents the developing flow results of the study, namely total void fraction at different axial locations along the TOPFLOW facility test section. The complete model description, as well as results of simulations and validation will be presented in the full paper.« less

40 CFR 1065.602 - Statistics.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... number of degrees of freedom, ν, as follows, noting that the εi are the errors (e.g., differences... measured continuously from the raw exhaust of an engine, its flow-weighted mean concentration is the sum of...

40 CFR 1065.602 - Statistics.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING... number of degrees of freedom, ν, as follows, noting that the εi are the errors (e.g., differences... measured continuously from the raw exhaust of an engine, its flow-weighted mean concentration is the sum of...

Investigation of Cooling Water Injection into Supersonic Rocket Engine Exhaust

NASA Astrophysics Data System (ADS)

Jones, Hansen; Jeansonne, Christopher; Menon, Shyam

2017-11-01

Water spray cooling of the exhaust plume from a rocket undergoing static testing is critical in preventing thermal wear of the test stand structure, and suppressing the acoustic noise signature. A scaled test facility has been developed that utilizes non-intrusive diagnostic techniques including Focusing Color Schlieren (FCS) and Phase Doppler Particle Anemometry (PDPA) to examine the interaction of a pressure-fed water jet with a supersonic flow of compressed air. FCS is used to visually assess the interaction of the water jet with the strong density gradients in the supersonic air flow. PDPA is used in conjunction to gain statistical information regarding water droplet size and velocity as the jet is broken up. Measurement results, along with numerical simulations and jet penetration models are used to explain the observed phenomena. Following the cold flow testing campaign a scaled hybrid rocket engine will be constructed to continue tests in a combusting flow environment similar to that generated by the rocket engines tested at NASA facilities. LaSPACE.

Initial in vitro testing of a paediatric continuous-flow total artificial heart.

PubMed

Fukamachi, Kiyotaka; Karimov, Jamshid H; Horvath, David J; Sunagawa, Gengo; Byram, Nicole A; Kuban, Barry D; Moazami, Nader

2018-06-01

Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations. We aimed to evaluate the in vitro performance of the initial prototype of our paediatric continuous-flow total artificial heart. The paediatric continuous-flow total artificial heart pump was downsized from the adult continuous-flow total artificial heart configuration by a scale factor of 0.70 (1/3 of total volume) to enable implantation in infants. System performance of this prototype was evaluated using the continuous-flow total artificial heart mock loop set to mimic paediatric circulation. We generated maps of pump performance and atrial pressure differences over a wide range of systemic vascular resistance/pulmonary vascular resistance and pump speeds. Performance data indicated left pump flow range of 0.4-4.7 l/min at 100 mmHg delta pressure. The left/right atrial pressure difference was maintained within ±5 mmHg with systemic vascular resistance/pulmonary vascular resistance ratios between 1.4 and 35, with/without pump speed modulation, verifying expected passive self-regulation of atrial pressure balance. The paediatric continuous-flow total artificial heart prototype met design requirements for self-regulation and performance; in vivo pump performance studies are ongoing.

Continuous-Flow In-Line Solvent-Swap Crystallization of Vitamin D3

PubMed Central

2017-01-01

A continuous tandem in-line evaporation–crystallization is presented. The process includes an in-line solvent-swap step, suitable to be coupled to a capillary based cooler. As a proof of concept, this setup is tested in a direct in-line acetonitrile mediated crystallization of Vitamin D3. This configuration is suitable to be coupled to a new end-to-end continuous microflow synthesis of Vitamin D3. By this procedure, vitamin particles can be crystallized in continuous flow and isolated using an in-line continuous filtration step. In one run in just 1 min of cooling time, ∼50% (w/w) crystals of Vitamin D3 are directly obtained. Furthermore, the polymorphic form as well as crystals shape and size properties are described in this paper.

Characteristics of the Langley 8-foot Transonic Tunnel with Slotted Test Section

NASA Technical Reports Server (NTRS)

Wright, Ray H; Ritchie, Virgil S; Pearson, Albin O

1958-01-01

A large wind tunnel, approximately 8 feet in diameter, has been converted to transonic operation by means of slots in the boundary extending in the direction of flow. The usefulness of such a slotted wind tunnel, already known with respect to the reduction of the subsonic blockage interference and the production of continuously variable supersonic flows, has been augmented by devising a slot shape with which a supersonic test region with excellent flow quality could be produced. Experimental locations of detached shock waves ahead of axially symmetric bodies at low supersonic speeds in the slotted test section agreed satisfactorily with predictions obtained by use of existing approximate methods.

Removal of selected emerging PPCP compounds using greater duckweed (Spirodela polyrhiza) based lab-scale free water constructed wetland.

PubMed

Li, Jianan; Zhou, Qizhi; Campos, Luiza C

2017-12-01

Greater duckweed (Spirodela polyrhiza) based lab-scale free water constructed wetland (CW) was employed for removing four emerging pharmaceuticals and personal care products (PPCPs) (i.e. DEET, paracetamol, caffeine and triclosan). Orthogonal design was used to test the effect of light intensity, aeration, E.coli abundance and plant biomass on the target compounds. Synthetic wastewater contaminated with the target compounds at concentration of 25 μg/L was prepared, and both batch and continuous flow experiments were conducted. Up to 100% removals were achieved for paracetamol (PAR), caffeine (CAF) and tricolsan (TCS) while the highest removal for DEET was 32.2% in batch tests. Based on orthogonal Duncan analysis, high light intensity (240 μmolmm -2 s -1 ), full aeration, high plant biomass (1.00 kg/m 2 ) and high E.coli abundance (1.0 × 10 6  CFU/100 mL) favoured elimination of the PPCPs. Batch verification test achieved removals of 17.1%, 98.8%, 96.4% and 95.4% for DEET, PAR, CAF and TCS respectively. Continuous flow tests with CW only and CW followed by stabilization tank (CW-ST) were carried out. Final removals of the PPCP contaminants were 32.6%, 97.7%, 98.0% and 100% for DEET, PAR, CAF and TCS, respectively, by CW system alone, while 43.3%, 97.5%, 98.2% and 100%, respectively, were achieved by CW-ST system. By adding the ST tank, PPCP concentrations decreased significantly faster (p < 0.05) compared with continuous flow CW alone. In addition, after removing aerators during continuous flow CW experiments, the treatment systems presented good stability for the PPCP removals. CW-ST showed better chemical oxygen demand (COD) and total organic carbon (TOC) removals (89.3%, 91.2%, respectively) than CW only (79.4%, 85.2%, respectively). However, poor DEET removal (<50%) and high E.coli abundance (up to 1.7 log increase) in the final treated water indicated further treatment processes may be required. Statistical analysis showed significant correlations (p < 0.05) between PPCPs and water quality parameters (e.g. COD, nitrate, phosphate), and between the four PPCP compounds for the continuous flow CW and CW-ST systems. Positive results encourage further test of Greater duckweed at pilot scale CW using real wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ranking nano-enabled hybrid media for simultaneous removal of contaminants with different chemistries: Pseudo-equilibrium sorption tests versus column tests.

PubMed

Custodio, Tomas; Garcia, Jose; Markovski, Jasmina; McKay Gifford, James; Hristovski, Kiril D; Olson, Larry W

2017-12-15

The underlying hypothesis of this study was that pseudo-equilibrium and column testing conditions would provide the same sorbent ranking trends although the values of sorbents' performance descriptors (e.g. sorption capacity) may vary because of different kinetics and competition effects induced by the two testing approaches. To address this hypothesis, nano-enabled hybrid media were fabricated and its removal performances were assessed for two model contaminants under multi-point batch pseudo-equilibrium and continuous-flow conditions. Calculation of simultaneous removal capacity indices (SRC) demonstrated that the more resource demanding continuous-flow tests are able to generate the same performance rankings as the ones obtained by conducing the simpler pseudo-equilibrium tests. Furthermore, continuous overlap between the 98% confidence boundaries for each SRC index trend, not only validated the hypothesis that both testing conditions provide the same ranking trends, but also pointed that SRC indices are statistically the same for each media, regardless of employed method. In scenarios where rapid screening of new media is required to obtain the best performing synthesis formulation, use of pseudo-equilibrium tests proved to be reliable. Considering that kinetics induced effects on sorption capacity must not be neglected, more resource demanding column test could be conducted only with the top performing media that exhibit the highest sorption capacity. Copyright © 2017 Elsevier B.V. All rights reserved.

Mod-2 wind turbine project assessment and cluster test plans

NASA Technical Reports Server (NTRS)

Gordon, L. H.

1982-01-01

An assessment of the Mod-2 Wind Turbine project is presented based on initial goals and present results. Specifically, the Mod-2 background, project flow, and a chronology of events/results leading to Mod-2 acceptance is presented. After checkout/acceptance of the three operating turbines, NASA/LeRC will continue management of a two year test program performed at the DOE Goodnoe Hills test site. This test program is expected to yield data necessary for the continued development and optimization of wind energy systems. These test activities, the implementation of, and the results to date are also presented.

Faster Blood Flow Rate Does Not Improve Circuit Life in Continuous Renal Replacement Therapy: A Randomized Controlled Trial.

PubMed

Fealy, Nigel; Aitken, Leanne; du Toit, Eugene; Lo, Serigne; Baldwin, Ian

2017-10-01

To determine whether blood flow rate influences circuit life in continuous renal replacement therapy. Prospective randomized controlled trial. Single center tertiary level ICU. Critically ill adults requiring continuous renal replacement therapy. Patients were randomized to receive one of two blood flow rates: 150 or 250 mL/min. The primary outcome was circuit life measured in hours. Circuit and patient data were collected until each circuit clotted or was ceased electively for nonclotting reasons. Data for clotted circuits are presented as median (interquartile range) and compared using the Mann-Whitney U test. Survival probability for clotted circuits was compared using log-rank test. Circuit clotting data were analyzed for repeated events using hazards ratio. One hundred patients were randomized with 96 completing the study (150 mL/min, n = 49; 250 mL/min, n = 47) using 462 circuits (245 run at 150 mL/min and 217 run at 250 mL/min). Median circuit life for first circuit (clotted) was similar for both groups (150 mL/min: 9.1 hr [5.5-26 hr] vs 10 hr [4.2-17 hr]; p = 0.37). Continuous renal replacement therapy using blood flow rate set at 250 mL/min was not more likely to cause clotting compared with 150 mL/min (hazards ratio, 1.00 [0.60-1.69]; p = 0.68). Gender, body mass index, weight, vascular access type, length, site, and mode of continuous renal replacement therapy or international normalized ratio had no effect on clotting risk. Continuous renal replacement therapy without anticoagulation was more likely to cause clotting compared with use of heparin strategies (hazards ratio, 1.62; p = 0.003). Longer activated partial thromboplastin time (hazards ratio, 0.98; p = 0.002) and decreased platelet count (hazards ratio, 1.19; p = 0.03) were associated with a reduced likelihood of circuit clotting. There was no difference in circuit life whether using blood flow rates of 250 or 150 mL/min during continuous renal replacement therapy.

Catheter-Based Measurements of Absolute Coronary Blood Flow and Microvascular Resistance: Feasibility, Safety, and Reproducibility in Humans.

PubMed

Xaplanteris, Panagiotis; Fournier, Stephane; Keulards, Daniëlle C J; Adjedj, Julien; Ciccarelli, Giovanni; Milkas, Anastasios; Pellicano, Mariano; Van't Veer, Marcel; Barbato, Emanuele; Pijls, Nico H J; De Bruyne, Bernard

2018-03-01

The principle of continuous thermodilution can be used to calculate absolute coronary blood flow and microvascular resistance (R). The aim of the study is to explore the safety, feasibility, and reproducibility of coronary blood flow and R measurements as measured by continuous thermodilution in humans. Absolute coronary flow and R can be calculated by thermodilution by infusing saline at room temperature through a dedicated monorail catheter. The temperature of saline as it enters the vessel, the temperature of blood and saline mixed in the distal part of the vessel, and the distal coronary pressure were measured by a pressure/temperature sensor-tipped guidewire. The feasibility and safety of the method were tested in 135 patients who were referred for coronary angiography. No significant adverse events were observed; in 11 (8.1%) patients, bradycardia and concomitant atrioventricular block appeared transiently and were reversed immediately on interruption of the infusion. The reproducibility of measurements was tested in a subgroup of 80 patients (129 arteries). Duplicate measurements had a strong correlation both for coronary blood flow (ρ=0.841, P <0.001; intraclass correlation coefficient=0.89, P <0.001) and R (ρ=0.780, P <0.001; intraclass correlation coefficient=0.89, P <0.001). In Bland-Altman plots, there was no significant bias or asymmetry. Absolute coronary blood flow (in L/min) and R (in mm Hg/L/min or Wood units) can be safely and reproducibly measured with continuous thermodilution. This approach constitutes a new opportunity for the study of the coronary microcirculation. © 2018 American Heart Association, Inc.

Solar oxidation and removal of arsenic--Key parameters for continuous flow applications.

PubMed

Gill, L W; O'Farrell, C

2015-12-01

Solar oxidation to remove arsenic from water has previously been investigated as a batch process. This research has investigated the kinetic parameters for the design of a continuous flow solar reactor to remove arsenic from contaminated groundwater supplies. Continuous flow recirculated batch experiments were carried out under artificial UV light to investigate the effect of different parameters on arsenic removal efficiency. Inlet water arsenic concentrations of up to 1000 μg/L were reduced to below 10 μg/L requiring 12 mg/L iron after receiving 12 kJUV/L radiation. Citrate however was somewhat surprisingly found to promote a detrimental effect on the removal process in the continuous flow reactor studies which is contrary to results found in batch scale tests. The impact of other typical water groundwater quality parameters (phosphate and silica) on the process due to their competition with arsenic for photooxidation products revealed a much higher sensitivity to phosphate ions compared to silicate. Other results showed no benefit from the addition of TiO2 photocatalyst but enhanced arsenic removal at higher temperatures up to 40 °C. Overall, these results have indicated the kinetic envelope from which a continuous flow SORAS single pass system could be more confidently designed for a full-scale community groundwater application at a village level. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bench-Scale Testing and Process Performance Projections of CO2 Capture by CO2–Binding Organic Liquids (CO2BOLs) With and Without Polarity-Swing-Assisted Regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Feng; Heldebrant, David J.; Mathias, Paul M.

This manuscript provides a detailed analysis of a continuous flow, bench scale study of the CO2BOL solvent platform with and without its Polarity Swing Assisted Regeneration (PSAR). This study encompassed four months of continuous flow testing of a candidate CO2BOL with a thermal regeneration and PSAR regeneration using decane antisolvent. In both regeneration schemes, steady state capture of >90 %CO2 was achieved using simulated flue gas at acceptable L/G ratios. Aspen Plus™ modeling was performed to assess process performance compared to previous equilibrium performance projections. This paper also includes net power projections, and comparisons to DOE’s Case 10 amine baseline.

40 CFR 60.624 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-water separator. Near the end of the recovery cycle, the entire flow of recovered solvent should be... solvent from the solvent recovery dryer at the termination of the recovery cycle is no greater than 0.05... cycle and the monitoring procedure should continue until the flow rate of solvent is less than or equal...

40 CFR 60.624 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-water separator. Near the end of the recovery cycle, the entire flow of recovered solvent should be... solvent from the solvent recovery dryer at the termination of the recovery cycle is no greater than 0.05... cycle and the monitoring procedure should continue until the flow rate of solvent is less than or equal...

40 CFR 60.624 - Test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-water separator. Near the end of the recovery cycle, the entire flow of recovered solvent should be... solvent from the solvent recovery dryer at the termination of the recovery cycle is no greater than 0.05... cycle and the monitoring procedure should continue until the flow rate of solvent is less than or equal...

40 CFR 60.624 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-water separator. Near the end of the recovery cycle, the entire flow of recovered solvent should be... solvent from the solvent recovery dryer at the termination of the recovery cycle is no greater than 0.05... cycle and the monitoring procedure should continue until the flow rate of solvent is less than or equal...

Experimental study of turbulence in blade end wall corner region

NASA Technical Reports Server (NTRS)

Raj, R.

1982-01-01

Corner flows and wall pressure fluctuations, design and fabrication of the test model, preliminary resuls on boundary layer, flow visualization, turbulence intensity and spectra measurements are presented. The design consideration and fabrication report on the newly built wind tunnel to be used for subsequent continuation of the research effort is also presented.

Multiphase flowmeter successfully measures three-phase flow at extremely high gas-volume fractions -- Gulf of Suez, Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leggett, R.B.; Borling, D.C.; Powers, B.S.

1998-02-01

A multiphase flowmeter (MPFM) installed in offshore Egypt has accurately measured three-phase flow in extremely gassy flow conditions. The meter is completely nonintrusive, with no moving parts, requires no flow mixing before measurement, and has no bypass loop to remove gas before multiphase measurement. Flow regimes observed during the field test of this meter ranged from severe slugging to annular flow caused by the dynamics of gas-lift gas in the production stream. Average gas-volume fraction ranged from 93 to 98% during tests conducted on seven wells. The meter was installed in the Gulf of Suez on a well protector platformmore » in the Gulf of Suez Petroleum Co. (Gupco) October field, and was placed in series with a test separator located on a nearby production platform. Wells were individually tested with flow conditions ranging from 1,300 to 4,700 B/D fluid, 2.4 to 3.9 MMscf/D of gas, and water cuts from 1 to 52%. The meter is capable of measuring water cuts up to 100%. Production was routed through both the MPFM and the test separator simultaneously as wells flowed with the assistance of gas-lift gas. The MPFM measured gas and liquid rates to within {+-} 10% of test-separator reference measurement flow rates, and accomplished this at gas-volume fractions from 93 to 96%. At higher gas-volume fractions up to 98%, accuracy deteriorated but the meter continued to provide repeatable results.« less

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

NASA Astrophysics Data System (ADS)

Yata, Vishnu Vardhan Reddy

This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable flow and intermittent flow spray cooling cases in comparison with the reference, steady flow spray cooling case with constant flowrate, continuous spray cooling. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. HFE-7100 dielectric liquid is selected as the working fluid. Two types of test samples are prepared on 10 mm x 10 mm x 2 mm copper substrates with matching size thick film resistors attached onto the opposite side, to generate heat and simulate high heat flux electronic devices. The test samples include: (i) plain, smooth surface, and (ii) microporous surface featuring 100 ?m thick copper-based coating prepared by dual stage electroplating technique. Experimental conditions involve HFE-7100 at atmospheric pressure and 30°C and 10°C subcooling. Steady flow spray cooling tests are conducted at flow rates of 2-5 ml/cm2.s, by controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. Variable flow and intermittent flow spray cooling tests are done at selected flowrate and subcooling conditions to investigate the effects of dynamic flow conditions on maintaining the target surface temperatures defined based on reference steady flow spray cooling performance.

Numerical simulation of failure behavior of granular debris flows based on flume model tests.

PubMed

Zhou, Jian; Li, Ye-xun; Jia, Min-cai; Li, Cui-na

2013-01-01

In this study, the failure behaviors of debris flows were studied by flume model tests with artificial rainfall and numerical simulations (PFC(3D)). Model tests revealed that grain sizes distribution had profound effects on failure mode, and the failure in slope of medium sand started with cracks at crest and took the form of retrogressive toe sliding failure. With the increase of fine particles in soil, the failure mode of the slopes changed to fluidized flow. The discrete element method PFC(3D) can overcome the hypothesis of the traditional continuous medium mechanic and consider the simple characteristics of particle. Thus, a numerical simulations model considering liquid-solid coupled method has been developed to simulate the debris flow. Comparing the experimental results, the numerical simulation result indicated that the failure mode of the failure of medium sand slope was retrogressive toe sliding, and the failure of fine sand slope was fluidized sliding. The simulation result is consistent with the model test and theoretical analysis, and grain sizes distribution caused different failure behavior of granular debris flows. This research should be a guide to explore the theory of debris flow and to improve the prevention and reduction of debris flow.

40 CFR 1065.280 - Paramagnetic and magnetopneumatic O2 detection analyzers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments O2 Measurements § 1065... diluted exhaust for batch or continuous sampling. You may use O2 measurements with intake air or fuel flow... 57443, Sept. 15, 2011;79 FR 23762, Apr. 28, 2014] Air-to-Fuel Ratio Measurements ...

Performance analysis of a continuous serpentine flow reactor for electrochemical oxidation of synthetic and real textile wastewater: Energy consumption, mass transfer coefficient and economic analysis.

PubMed

Pillai, Indu M Sasidharan; Gupta, Ashok K

2017-05-15

A continuous flow electrochemical reactor was developed, and its application was tested for the treatment of textile wastewater. A parallel plate configuration with serpentine flow was chosen for the continuous flow reactor. Uniparameter optimization was carried out for electrochemical oxidation of synthetic and real textile wastewater (collected from the inlet of the effluent treatment plant). Chemical Oxygen Demand (COD) removal efficiency of 90% was achieved for synthetic textile wastewater (initial COD - 780 mg L -1 ) at a flow rate of 500 mL h -1 (retention time of 6 h) and a current density of 1.15 mA cm -2 and the energy consumption for the degradation was 9.2 kWh (kg COD) -1 . The complete degradation of real textile wastewater (initial COD of 368 mg L -1 ) was obtained at a current density of 1.15 mA cm -2 , NaCl concentration of 1 g L -1 and retention time of 6 h. Energy consumption and mass transfer coefficient of the reactions were calculated. The continuous flow reactor performed better than batch reactor with reference to energy consumption and economy. The overall treatment cost for complete COD removal of real textile wastewater was 5.83 USD m -3 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Anh To | NREL

Science.gov Websites

pyrolysis vapors Catalytic depolymerization of biomass Process scale-up for catalyst synthesis and testing continuous flow reactors (gas & liquid phases) Catalyst synthesis: zeolites, supported metals, and

Leaching of cadmium and tellurium from cadmium telluride (CdTe) thin-film solar panels under simulated landfill conditions.

PubMed

Ramos-Ruiz, Adriana; Wilkening, Jean V; Field, James A; Sierra-Alvarez, Reyes

2017-08-15

A crushed non-encapsulated CdTe thin-film solar cell was subjected to two standardized batch leaching tests (i.e., Toxicity Characteristic Leaching Procedure (TCLP) and California Waste Extraction Test (WET)) and to a continuous-flow column test to assess cadmium (Cd) and tellurium (Te) dissolution under conditions simulating the acidic- and the methanogenic phases of municipal solid waste landfills. Low levels of Cd and Te were solubilized in both batch leaching tests (<8.2% and <3.6% of added Cd and Te, respectively). On the other hand, over the course of 30days, 73% of the Cd and 21% of the Te were released to the synthetic leachate of a continuous-flow column simulating the acidic landfill phase. The dissolved Cd concentration was 3.24-fold higher than the TCLP limit (1mgL -1 ), and 650-fold higher than the maximum contaminant level established by the US-EPA for this metal in drinking water (0.005mgL -1 ). In contrast, the release of Cd and Te to the effluent of the continuous-flow column simulating the methanogenic phase of a landfill was negligible. The remarkable difference in the leaching behavior of CdTe in the columns is related to different aqueous pH and redox conditions promoted by the microbial communities in the columns, and is in agreement with thermodynamic predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

Apparatus for diffusion separation

DOEpatents

Nierenberg, William A.; Pontius, Rex B.

1976-08-10

1. The method of testing the separation efficiency of porous permeable membranes which comprises causing a stream of a gaseous mixture to flow into contact with one face of a finely porous permeable membrane under such conditions that a major fraction of the mixture diffuses through the membrane, maintaining a rectangular cross section of the gaseous stream so flowing past said membrane, continuously recirculating the gas that diffuses through said membrane and continuously withdrawing the gas that does not diffuse through said membrane and maintaining the volume of said recirculating gas constant by continuously introducing into said continuously recirculating gas stream a mass of gas equivalent to that which is continuously withdrawn from said gas stream and comparing the concentrations of the light component in the entering gas, the withdrawn gas and the recirculated gas in order to determine the efficiency of said membrane.

Impact of continuous positive airway pressure (CPAP) on the respiratory capacity of chronic kidney disease patients under hemodialysis treatment.

PubMed

Xavier, Vivian Bertoni; Roxo, Renata Spósito; Miorin, Luiz Antônio; Dos Santos Alves, Vera Lúcia; Dos Santos Sens, Yvoty Alves

2015-06-01

Chronic kidney disease (CKD) patients on long-term dialysis present changes in pulmonary function and respiratory muscle strength, negatively influencing physical capacity. To analyze the impact of a continuous positive airway pressure (CPAP) protocol on the respiratory capacity of CKD patients under hemodialysis. A randomized clinical trial was conducted involving 40 CKD patients 19-83 years old divided into two groups: control (n = 20) and CPAP (n = 20). Subjects were assessed on the respiratory muscle function test, maximal respiratory pressures, peak flow and 6-min walk test, at baseline and again at the 2-month follow-up. CPAP group patients were submitted to CPAP protocol (PEEP: 5 cm H2O, flow: 15 L/min, FiO2: 33 %) three times per week during hemodialysis sessions. The CPAP group showed higher forced vital capacity, forced expiratory volume in one second, peak expiratory flow, maximal inspiratory pressure, peak flow, as well as lower systolic blood pressure, heart rate, respiratory rate and Borg scale, in addition to a longer distance travelled on the 6-min walk test, compared with the control group. The introduction of a CPAP protocol during hemodialysis sessions had a positive impact on pulmonary function and physical capacity in CKD patients.

Low-flow characteristics of streams in Virginia

USGS Publications Warehouse

Hayes, Donald C.

1991-01-01

Streamflow data were collected and low-flow characteristics computed for 715 gaged sites in Virginia Annual minimum average 7-consecutive-day flows range from 0 to 2,195 cubic feet per second for a 2-year recurrence interval and from 0 to 1,423 cubic feet per second for a 10-year recurrence interval. Drainage areas range from 0.17 to 7,320 square miles. Existing and discontinued gaged sites are separated into three types: long-term continuous-record sites, short-term continuous-record sites, and partial-record sites. Low-flow characteristics for long-term continuous-record sites are determined from frequency curves of annual minimum average 7-consecutive-day flows . Low-flow characteristics for short-term continuous-record sites are estimated by relating daily mean base-flow discharge values at a short-term site to concurrent daily mean discharge values at nearby long-term continuous-record sites having similar basin characteristics . Low-flow characteristics for partial-record sites are estimated by relating base-flow measurements to daily mean discharge values at long-term continuous-record sites. Information from the continuous-record sites and partial-record sites in Virginia are used to develop two techniques for estimating low-flow characteristics at ungaged sites. A flow-routing method is developed to estimate low-flow values at ungaged sites on gaged streams. Regional regression equations are developed for estimating low-flow values at ungaged sites on ungaged streams. The flow-routing method consists of transferring low-flow characteristics from a gaged site, either upstream or downstream, to a desired ungaged site. A simple drainage-area proration is used to transfer values when there are no major tributaries between the gaged and ungaged sites. Standard errors of estimate for108 test sites are 19 percent of the mean for estimates of low-flow characteristics having a 2-year recurrence interval and 52 percent of the mean for estimates of low-flow characteristics having a 10-year recurrence interval . A more complex transfer method must be used when major tributaries enter the stream between the gaged and ungaged sites. Twenty-four stream networks are analyzed, and predictions are made for 84 sites. Standard errors of estimate are 15 percent of the mean for estimates of low-flow characteristics having a 2-year recurrence interval and 22 percent of the mean for estimates of low-flow characteristics having a 10-year recurrence interval. Regional regression equations were developed for estimating low-flow values at ungaged sites on ungaged streams. The State was divided into eight regions on the basis of physiography and geographic grouping of the residuals computed in regression analyses . Basin characteristics that were significant in the regression analysis were drainage area, rock type, and strip-mined area. Standard errors of prediction range from 60 to139 percent for estimates of low-flow characteristics having a 2-year recurrence interval and 90 percent to 172 percent for estimates of low-flow characteristics having a 10-year recurrence interval.

Development of a flow-through system for the fish embryo toxicity test (FET) with the zebrafish (Danio rerio).

PubMed

Lammer, E; Kamp, H G; Hisgen, V; Koch, M; Reinhard, D; Salinas, E R; Wendler, K; Zok, S; Braunbeck, Th

2009-10-01

The acute fish test is still a mandatory component in chemical hazard and risk assessment. However, one of the objectives of the new European chemicals policy (REACH - Registration, Evaluation, Authorization and Restriction of Chemicals) is to promote non-animal testing. For whole effluent testing in Germany, the fish embryo toxicity test (FET) with the zebrafish (Danio rerio) has been an accepted and mandatory replacement of the fish test since January 2005. For chemical testing, however, further optimization of the FET is required to improve the correlation between the acute fish test and the alternative FET. Since adsorption of the test chemical to surfaces may reduce available exposure concentrations, a flow-through system for the FET using modified commercially available polystyrene 24-well microtiter plates was developed, thus combining the advantages of the standard FET with those of continuous delivery of test substances. The advantages of the design presented include: small test footprint, availability of adequate volumes of test solution for subsequent chemical analysis, and sufficient flow to compensate for effects of non-specific adsorption within 24h. The flow-through test system can also be utilized to conduct longer-term embryo larval fish tests, thus offering the possibility for teratogenicity testing.

River-induced flow dynamics in long-screen wells and impact on aqueous samples.

PubMed

Vermeul, Vince R; McKinley, James P; Newcomer, Darrell R; Mackley, Robert D; Zachara, J M

2011-01-01

Previously published field investigations and modeling studies have demonstrated the potential for sample bias associated with vertical wellbore flow in conventional monitoring wells constructed with long-screened intervals. This article builds on the existing body of literature by (1) demonstrating the utility of continuous (i.e., hourly measurements for ∼1 month) ambient wellbore flow monitoring and (2) presenting results from a field experiment where relatively large wellbore flows (up to 4 L/min) were induced by aquifer hydrodynamics associated with a fluctuating river boundary located approximately 250 m from the test well. The observed vertical wellbore flows were strongly correlated with fluctuations in river stage, alternating between upward and downward flow throughout the monitoring period in response to changes in river stage. Continuous monitoring of ambient wellbore flows using an electromagnetic borehole flowmeter allowed these effects to be evaluated in concert with continuously monitored river-stage elevations (hourly) and aqueous uranium concentrations (daily) in a long-screen well and an adjacent multilevel well cluster. This study demonstrates that when contaminant concentrations within the aquifer vary significantly over the depth interval interrogated, river-induced vertical wellbore flow can result in variations in measured concentration that nearly encompass the full range of variation in aquifer contaminant concentration with depth. Copyright © 2010 Battelle Memorial Institute. Journal compilation © 2010 National Ground Water Association.

The 3-D CFD modeling of gas turbine combustor-integral bleed flow interaction

NASA Technical Reports Server (NTRS)

Chen, D. Y.; Reynolds, R. S.

1993-01-01

An advanced 3-D Computational Fluid Dynamics (CFD) model was developed to analyze the flow interaction between a gas turbine combustor and an integral bleed plenum. In this model, the elliptic governing equations of continuity, momentum and the k-e turbulence model were solved on a boundary-fitted, curvilinear, orthogonal grid system. The model was first validated against test data from public literature and then applied to a gas turbine combustor with integral bleed. The model predictions agreed well with data from combustor rig testing. The model predictions also indicated strong flow interaction between the combustor and the integral bleed. Integral bleed flow distribution was found to have a great effect on the pressure distribution around the gas turbine combustor.

Feasibility of utilizing bioindicators for testing microbial inactivation in sweetpotato purees processed with a continuous-flow microwave system.

PubMed

Brinley, T A; Dock, C N; Truong, V-D; Coronel, P; Kumar, P; Simunovic, J; Sandeep, K P; Cartwright, G D; Swartzel, K R; Jaykus, L-A

2007-06-01

Continuous-flow microwave heating has potential in aseptic processing of various food products, including purees from sweetpotatoes and other vegetables. Establishing the feasibility of a new processing technology for achieving commercial sterility requires evaluating microbial inactivation. This study aimed to assess the feasibility of using commercially available plastic pouches of bioindicators containing spores of Geobacillius stearothermophilus ATCC 7953 and Bacillus subtilis ATCC 35021 for evaluating the degree of microbial inactivation achieved in vegetable purees processed in a continuous-flow microwave heating unit. Sweetpotato puree seeded with the bioindicators was subjected to 3 levels of processing based on the fastest particles: undertarget process (F(0) approximately 0.65), target process (F(0) approximately 2.8), and overtarget process (F(0) approximately 10.10). After initial experiments, we found it was necessary to engineer a setup with 2 removable tubes connected to the continuous-flow microwave system to facilitate the injection of indicators into the unit without interrupting the puree flow. Using this approach, 60% of the indicators injected into the system could be recovered postprocess. Spore survival after processing, as evaluated by use of growth indicator dyes and standard plating methods, verified inactivation of the spores in sweetpotato puree. The log reduction results for B. subtilis were equivalent to the predesigned degrees of sterilization (F(0)). This study presents the first report suggesting that bioindicators such as the flexible, food-grade plastic pouches can be used for microbial validation of commercial sterilization in aseptic processing of foods using a continuous-flow microwave system.

Coal desulfurization by low temperature chlorinolysis, phase 2

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Grohmann, K.; Rohatgi, N.; Ernest, J.; Feller, D.

1980-01-01

An engineering scale reactor system was constructed and operated for the evaluation of five high sulfur bituminous coals obtained from Kentucky, Ohio, and Illinois. Forty-four test runs were conducted under conditions of 100 by 200 mesh coal,solvents - methlychloroform and water, 60 to 130 C, 0 to 60 psig, 45 to 90 minutes, and gaseous chlorine flow rate of up to 24 SCFH. Sulfur removals demonstrated for the five coals were: maximum total sulfur removal of 46 to 89% (4 of 5 coals with methylchloroform) and 0 to 24% with water. In addition, an integrated continuous flow mini-pilot plant was designed and constructed for a nominal coal rate of 2 kilograms/hour which will be operated as part of the follow-on program. Equipment flow sheets and design drawings are included for both the batch and continuous flow mini-pilot plants.

Ammonia Offgassing from SA9T

NASA Technical Reports Server (NTRS)

Monje, Oscar; Nolek, Sara D.; Wheeler, Raymond M.

2011-01-01

NH3 is a degradation product of SA9T, a solid-amine sorbent developed by Hamilton Sundstrand, that is continually emitted into the gas stream being conditioned by this sorbent. NH3 offgassing rates were measured using FTIR spectroscopy using a packed bed at similar contact times as offgassing tests conducted at Hamilton Sundstrand and at the Ames Research Center. The bed was challenged with moist air at several flow rates and humidities and NH3 concentration of the effluent was measured for several hours. The NH3 offgassing rates in open-loop testing were calculated from the steady state outlet NH3 concentration and flow rate. NH3 offgassing rates from SA9T were found to be influenced by the contact time with the adsorbent (flow rate) and by the humidity of the inlet gas stream, which are consistent with previous studies. Closed-loop vacuum-swing adsorption cycling rates verified that NH3 offgassing continues when a constant source of water vapor is present.

40 CFR 1065.602 - Statistics.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING...., differences) between each pair of y refi and y i: ER28AP14.011 ER28AP14.012 Table 1 of § 1065.602—Critical t... concentration is measured continuously from the raw exhaust of an engine, its flow-weighted mean concentration...

40 CFR 1065.280 - Paramagnetic and magnetopneumatic O2 detection analyzers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments O2 Measurements § 1065... diluted exhaust for batch or continuous sampling. You may use O2 measurements with intake air or fuel flow...), regardless of the uncompensated signal's bias. [73 FR 37300, June 30, 2008] Air-to-Fuel Ratio Measurements ...

Trends and shifts in streamflow in Hawaii, 1913-2008

USGS Publications Warehouse

Bassiouni, Maoya; Oki, Delwyn S.

2013-01-01

This study addresses a need to document changes in streamflow and base flow (groundwater discharge to streams) in Hawai'i during the past century. Statistically significant long-term (1913-2008) downward trends were detected (using the nonparametric Mann-Kendall test) in low-streamflow and base-flow records. These long-term downward trends are likely related to a statistically significant downward shift around 1943 detected (using the nonparametric Pettitt test) in index records of streamflow and base flow. The downward shift corresponds to a decrease of 22% in median streamflow and a decrease of 23% in median base flow between the periods 1913-1943 and 1943-2008. The shift coincides with other local and regional factors, including a change from a positive to a negative phase in the Pacific Decadal Oscillation, shifts in the direction of the trade winds over Hawai'i, and a reforestation programme. The detected shift and long-term trends reflect region-wide changes in climatic and land-cover factors. A weak pattern of downward trends in base flows during the period 1943-2008 may indicate a continued decrease in base flows after the 1943 shift. Downward trends were detected more commonly in base-flow records than in high-streamflow, peak-flow, and rainfall records. The decrease in base flow is likely related to a decrease in groundwater storage and recharge and therefore is a valuable indicator of decreasing water availability and watershed vulnerability to hydrologic changes. Whether the downward trends will continue is largely uncertain given the uncertainty in climate-change projections and watershed responses to changes.

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

Influence of different heating types on the pumping performance of a bubble pump

NASA Astrophysics Data System (ADS)

Bierling, Bernd; Schmid, Fabian; Spindler, Klaus

2017-11-01

This study presents an experimental investigation of the influence of different heating types on the pumping performance of a bubble pump. A test rig was set up at the Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart. The vertical lift tube is made of copper with an inner diameter of 8 mm and a length of 1.91 m. The working fluid is demineralized water. The test rig offers the possibility to vary the supplied heat flow (0 W - 750 W), the resulting supplied heat flux and the location of the heating. Investigations were carried out using spot heating, partial-length heating and full-length heating. A Coriolis mass flowmeter was successfully implemented which measures the vapor mass flow rate continuously. The improvement of the vapor mass flow rate measurement by using the continuous measurement method compared to a discontinuous one is discussed. Furthermore, the influence of an unstable inlet temperature of the working fluid entering the lift tube on the pumping performance is investigated. The focus of this publication lies on the build-up of the test rig with the measurement setup and the analysis of the pumping performance for the three heating types. The measurement results show a big influence of the heating type on the pumping performance. The lower the relative length of the heating, the higher is the pumping ratio which is defined as the lifted liquid mass flow rate in relation to the generated vapor mass flow rate.

Further development and testing of the metabolic gas analyzer

NASA Technical Reports Server (NTRS)

1973-01-01

Continued development of a metabolic monitor utilizing a mass spectrometer and digital computer to perform measurements and data reduction, is reported. The device prints-out breath-by-breath values for 02 consumption, C02 production, minute volume and tidal volume. The flow is measured by introduction of a tracer gas to the expired gas stream. Design modifications to reduce pressure drop in the flow splitter to one inch of water at 600 liters/min flow and to extend the range of linear flow measurement to 1000 liters/min are discussed.

Remote Infrared Thermography for In-Flight Flow Diagnostics

NASA Technical Reports Server (NTRS)

Shiu, H. J.; vanDam, C. P.

1999-01-01

The feasibility of remote in-flight boundary layer visualization via infrared in incompressible flow was established in earlier flight experiments. The past year's efforts focused on refining and determining the extent and accuracy of this technique of remote in-flight flow visualization via infrared. Investigations were made into flow separation visualization, visualization at transonic conditions, shock visualization, post-processing to mitigate banding noise in the NITE Hawk's thermograms, and a numeric model to predict surface temperature distributions. Although further flight tests are recommended, this technique continues to be promising.

Vapor spill pipe monitor

DOEpatents

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

1983-06-23

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.

Cavitation control on a 2D hydrofoil through a continuous tangential injection of liquid: Experimental study

NASA Astrophysics Data System (ADS)

Timoshevskiy, M. V.; Zapryagaev, I. I.; Pervunin, K. S.; Markovich, D. M.

2016-10-01

In the paper, the possibility of active control of a cavitating flow over a 2D hydrofoil that replicates a scaled-down model of high-pressure hydroturbine guide vane (GV) was tested. The flow manipulation was implemented by a continuous tangential liquid injection at different flow rates through a spanwise slot in the foil surface. In experiments, the hydrofoil was placed in the test channel at the attack angle of 9°. Different cavitation conditions were reached by varying the cavitation number and injection velocity. In order to study time dynamics and spatial patterns of partial cavities, high-speed imaging was employed. A PIV method was used to measure the mean and fluctuating velocity fields over the hydrofoil. Hydroacoustic measurements were carried out by means of a pressure transducer to identify spectral characteristics of the cavitating flow. It was found that the present control technique is able to modify the partial cavity pattern (or even totally suppress cavitation) in case of stable sheet cavitation and change the amplitude of pressure pulsations at unsteady regimes. The injection technique makes it also possible to significantly influence the spatial distributions of the mean velocity and its turbulent fluctuations over the GV section for non-cavitating flow and sheet cavitation.

In vitro characterization of a magnetically suspended continuous flow ventricular assist device.

PubMed

Kim, H C; Bearnson, G B; Khanwilkar, P S; Olsen, D B; Maslen, E H; Allaire, P E

1995-01-01

A magnetically suspended continuous flow ventricular assist device using magnetic bearings was developed aiming at an implantable ventricular assist device. The main advantage of this device includes no mechanical wear and minimal chance of blood trauma such, as thrombosis and hemolysis, because there is no mechanical contact between the stationary and rotating parts. The total system consists of two subsystems: the centrifugal pump and the magnetic bearing. The centrifugal pump is comprised of a 4 vane logarithmic spiral radial flow impeller and a brushless DC motor with slotless stator, driven by the back emf commutation scheme. Two radial and one thrust magnetic bearing that dynamically controls the position of the rotor in a radial and axial direction, respectively, contains magnetic coils, the rotor's position sensors, and feedback electronic control system. The magnetic bearing system was able to successfully suspend a 365.5g rotating part in space and sustain it for up to 5000 rpm of rotation. Average force-current square factor of the magnetic bearing was measured as 0.48 and 0.44 (kg-f/Amp2) for radial and thrust bearing, respectively. The integrated system demonstrated adequate performance in mock circulation tests by providing a 6 L/min flow rate against 100 mmHg differential pressure at 2300 rpm. Based on these in vitro performance test results, long-term clinical application of the magnetically suspended continuous flow ventricular assist device is very promising after system optimization with a hybrid system using both active (electromagnet) and passive (permanent magnets) magnet bearings.

Mobile magnetic particles as solid-supports for rapid surface-based bioanalysis in continuous flow.

PubMed

Peyman, Sally A; Iles, Alexander; Pamme, Nicole

2009-11-07

An extremely versatile microfluidic device is demonstrated in which multi-step (bio)chemical procedures can be performed in continuous flow. The system operates by generating several co-laminar flow streams, which contain reagents for specific (bio)reactions across a rectangular reaction chamber. Functionalized magnetic microparticles are employed as mobile solid-supports and are pulled from one side of the reaction chamber to the other by use of an external magnetic field. As the particles traverse the co-laminar reagent streams, binding and washing steps are performed on their surface in one operation in continuous flow. The applicability of the platform was first demonstrated by performing a proof-of-principle binding assay between streptavidin coated magnetic particles and biotin in free solution with a limit of detection of 20 ng mL(-1) of free biotin. The system was then applied to a mouse IgG sandwich immunoassay as a first example of a process involving two binding steps and two washing steps, all performed within 60 s, a fraction of the time required for conventional testing.

Pulmonary function tests do not predict mortality in patients undergoing continuous-flow left ventricular assist device implantation.

PubMed

Bedzra, Edo K S; Dardas, Todd F; Cheng, Richard K; Pal, Jay D; Mahr, Claudius; Smith, Jason W; Shively, Kent; Masri, S Carolina; Levy, Wayne C; Mokadam, Nahush A

2017-12-01

To investigate the effect of pulmonary function testing on outcomes after continuous flow left ventricular assist device implantation. A total of 263 and 239 patients, respectively, had tests of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide preoperatively for left ventricular assist device implantations between July 2005 and September 2015. Kaplan-Meier analysis and multivariable Cox regressions were performed to evaluate mortality. Patients were analyzed in a single cohort and across 5 groups. Postoperative intensive care unit and hospital lengths of stay were evaluated with negative binomial regressions. There is no association of forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide with survival and no difference in mortality at 1 and 3 years between the groups (log rank P = .841 and .713, respectively). Greater values in either parameter were associated with decreased hospital lengths of stay. Only diffusing capacity of the lungs for carbon monoxide was associated with increased intensive care unit length of stay in the group analysis (P = .001). Ventilator times, postoperative pneumonia, reintubation, and tracheostomy rates were similar across the groups. Forced expiratory volume in 1 second and diffusing capacity of the lungs for carbon monoxide are not associated with operative or long-term mortality in patients undergoing continuous flow left ventricular assist device implantation. These findings suggest that these abnormal pulmonary function tests alone should not preclude mechanical circulatory support candidacy. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Cavitation in liquid cryogens. 1: Venturi

NASA Technical Reports Server (NTRS)

Hord, J.; Anderson, L. M.; Hall, W. J.

1972-01-01

The results of continuing cavitation studies are reported. The cavitation characteristics of liquid hydrogen and liquid nitrogen flowing in a transparent plastic Venturi are discussed. Thermodynamic data, consisting of pressure and temperature measurements within fully developed hydrogen cavities, are reported. Details concerning test apparatus, test procedure, and data correlation techniques are given.

On-chip determination of C-reactive protein using magnetic particles in continuous flow.

PubMed

Phurimsak, Chayakom; Tarn, Mark D; Peyman, Sally A; Greenman, John; Pamme, Nicole

2014-11-04

We demonstrate the application of a multilaminar flow platform, in which functionalized magnetic particles are deflected through alternating laminar flow streams of reagents and washing solutions via an external magnet, for the rapid detection of the inflammatory biomarker, C-reactive protein (CRP). The two-step sandwich immunoassay was accomplished in less than 60 s, a vast improvement on the 80-300 min time frame required for enzyme-linked immunosorbent assays (ELISA) and the 50 min necessary for off-chip magnetic particle-based assays. The combination of continuous flow and a stationary magnet enables a degree of autonomy in the system, while a detection limit of 0.87 μg mL(-1) makes it suitable for the determination of CRP concentrations in clinical diagnostics. Its applicability was further proven by assaying real human serum samples and comparing those results to values obtained using standard ELISA tests.

Fluid Dynamic Characterization of a Polymeric Heart Valve Prototype (Poli-Valve) tested under Continuous and Pulsatile Flow Conditions

PubMed Central

De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D.; Costantino, Maria Laura

2016-01-01

Introduction Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy, the latter display better fluid dynamic behaviour but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the haemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of two groups of newly developed supra-annular tri-leaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. Methods Two types of Poli-Valves made of SBC differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. An ad - hoc designed pulse duplicator allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the valve’s behaviour. Results Both types Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by ISO 5840 Standard. Results were compared with five mechanical heart valves (MHVs) and five tissue heart valves (THVs), currently available on the market. Conclusion Based on these results, polymeric heart valves based on styrenic block copolymers, as Poli-Valves are, can be considered as promising alternative for heart valve replacement in near future. PMID:26689146

Fluid dynamic characterization of a polymeric heart valve prototype (Poli-Valve) tested under continuous and pulsatile flow conditions.

PubMed

De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D; Costantino, Maria Laura

2015-11-01

Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of 2 groups of newly developed supra-annular, trileaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. 2 types of Poli-Valves made of SBC and differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. A pulse duplicator designed ad hoc allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the behavior of the valve. Both types of Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by the ISO 5840 Standard. Results were compared with 5 mechanical heart valves (MHVs) and 5 tissue heart valves (THVs), currently available on the market. Based on these results, PHVs based on styrenic block copolymers, as are Poli-Valves, can be considered a promising alternative for heart valve replacement in the near future.

Safe Surgery Trainer

DTIC Science & Technology

2014-11-15

design, testing, and development. b) Prototype Development – Continue developing SST software, game -flow, and mechanics. Continue developing art...refined learning objectives into measurement outlines. Update IRB submissions, edit usability game play study, and update I/ITSEC IRB. Provide case...minimal or near zero. 9) Related Activities a) Presenting at the Design of Learning Games Community Workshop, at I/ITSEC, Wednesday, Dec 3 rd

Fluid Flow Patterns During Production from Gas Hydrates in the Laboratory compared to Field Settings: LARS vs. Mallik

NASA Astrophysics Data System (ADS)

Strauch, B.; Heeschen, K. U.; Priegnitz, M.; Abendroth, S.; Spangenberg, E.; Thaler, J.; Schicks, J. M.

2015-12-01

The GFZ's LArge Reservoir Simulator LARS allows for the simulation of the 2008 Mallik gas hydrate production test and the comparison of fluid flow patterns and their driving forces. Do we see the gas flow pattern described for Mallik [Uddin, M. et al., J. Can. Petrol Tech, 50, 70-89, 2011] in a pilot scale test? If so, what are the driving forces? LARS has a network of temperature sensors and an electric resistivity tomography (ERT) enabling a good spatial resolution of gas hydrate occurrences, water and gas distribution, and changes in temperature in the sample. A gas flow meter and a water trap record fluid flow patterns and a backpressure valve has controlled the depressurization equivalent to the three pressure stages (7.0 - 5.0 - 4.2 MPa) applied in the Mallik field test. The environmental temperature (284 K) and confining pressure (13 MPa) have been constant. The depressurization induced immediate endothermic gas hydrate dissociation until re-establishment of the stability conditions by a consequent temperature decrease. Slight gas hydrate dissociation continued at the top and upper lateral border due to the constant heat input from the environment. Here transport pathways were short and permeability higher due to lower gas hydrate saturation. At pressures of 7.0 and 5.0 MPa the LARS tests showed high water flow rates and short irregular spikes of gas production. The gas flow patterns at 4.2 MPa and 3.0MPa resembled those of the Mallik test. In LARS the initial gas surges overlap with times of hydrate instability while water content and lengths of pathways had increased. Water production was at a minimum. A rapidly formed continuous gas phase caused the initial gas surges and only after gas hydrate dissociation decreased to a minimum the single gas bubbles get trapped before slowly coalescing again. In LARS, where pathways were short and no additional water was added, a transport of microbubbles is unlikely to cause a gas surge as suggested for Mallik.

Optimization of transonic wind tunnel data acquisition and control systems for providing continuous mode tests

NASA Astrophysics Data System (ADS)

Petronevich, V. V.

2016-10-01

The paper observes the issues related to the increase of efficiency and information content of experimental research in transonic wind tunnels (WT). In particular, questions of optimizing the WT Data Acquisition and Control Systems (DACS) to provide the continuous mode test method are discussed. The problem of Mach number (M number) stabilization in the test section of the large transonic compressor-type wind tunnels at subsonic flow conditions with continuous change of the aircraft model angle of attack is observed on the example of T-128 wind tunnel. To minimize the signals distortion in T-128 DACS measurement channels the optimal MGCplus filter settings of the data acquisition system used in T-128 wind tunnel to measure loads were experimentally determined. As a result of the tests performed a good agreement of the results of balance measurements for pitch/pause and continuous test modes was obtained. Carrying out balance tests for pitch/pause and continuous test methods was provided by the regular data acquisition and control system of T-128 wind tunnel with unified software package POTOK. The architecture and functional abilities of POTOK software package are observed.

Milk Flow Rates from bottle nipples used after hospital discharge.

PubMed

Pados, Britt Frisk; Park, Jinhee; Thoyre, Suzanne M; Estrem, Hayley; Nix, W Brant

To test the milk flow rates and variability in flow rates of bottle nipples used after hospital discharge. Twenty-six nipple types that represented 15 common brands as well as variety in price per nipple and store location sold (e.g., Babies R' Us, Walmart, Dollar Store) were chosen for testing. Ten of each nipple type (n = 260 total) were tested by measuring the amount of infant formula expressed in 1 minute using a breast pump. Mean milk flow rate (mL/min) and coefficient of variation (CV) were calculated. Flow rates of nipples within brand were compared statistically. Milk flow rates varied from 1.68 mL/min for the Avent Natural Newborn Flow to 85.34 mL/min for the Dr. Brown's Standard Y-cut. Variability between nipple types also varied widely, from .03 for the Dr. Brown's Standard Level 3 to .37 for MAM Nipple 1 Slow Flow. The extreme range of milk flow rates found may be significant for medically fragile infants being discharged home who are continuing to develop oral feeding skills. The name of the nipple does not provide clear information about the flow rate to guide parents in decision making. Variability in flow rates within nipples of the same type may complicate oral feeding for the medically fragile infant who may not be able to adapt easily to change in flow rates. Both flow rate and variability should be considered when guiding parents to a nipple choice.

Non-holonomic integrators

NASA Astrophysics Data System (ADS)

Cortés, J.; Martínez, S.

2001-09-01

We introduce a discretization of the Lagrange-d'Alembert principle for Lagrangian systems with non-holonomic constraints, which allows us to construct numerical integrators that approximate the continuous flow. We study the geometric invariance properties of the discrete flow which provide an explanation for the good performance of the proposed method. This is tested on two examples: a non-holonomic particle with a quadratic potential and a mobile robot with fixed orientation.

Improvement of Subsonic Basic Research Tunnel Flow Quality as Applied to Wall Mounted Testing

NASA Technical Reports Server (NTRS)

Howerton, Brian M.

1995-01-01

A survey to determine the characteristics of a boundary layer that forms on the wall of the Subsonic Basic Research Tunnel has been performed. Early results showed significant differences in the velocity profiles as measured spanwise across the wall. An investigation of the flow in the upstream contraction revealed the presence of a separation bubble at the beginning of the contraction which caused much of the observed unsteadiness. Vortex generators were successfully applied to the contraction inlet to alleviate the separation. A final survey of the wall boundary layer revealed variations in the displacement and momentum thicknesses to be less than +/- 5% for all but the most upper portion of the wall. The flow quality was deemed adequate to continue the planned follow-on tests to help develop the semi-span test technique.

Electrophoretic separator for purifying biologicals, part 1

NASA Technical Reports Server (NTRS)

Mccreight, L. R.

1978-01-01

A program to develop an engineering model of an electrophoretic separator for purifying biologicals is summarized. An extensive mathematical modeling study and numerous ground based tests were included. Focus was placed on developing an actual electrophoretic separator of the continuous flow type, configured and suitable for flight testing as a space processing applications rocket payload.

Cardio-Pulmonary Function Testing. Continuing Education Curriculum for Respiratory Therapy.

ERIC Educational Resources Information Center

Saint Paul Technical Vocational Inst., MN.

Compiled from interviews with personnel in pulmonary function testing (PFT) laboratories in the Minneapolis/St. Paul area, this competency-based curriculum guide is intended to provide a knowledge of PFT for persons who provide respiratory care. The guide contains 20 sections covering the following topics: vital capacity, flow measurements,…

Detonation-flame arrester devices for gasoline cargo vapor recovery systems

NASA Technical Reports Server (NTRS)

Bjorklund, R. A.; Ryason, P. R.

1980-01-01

Empirical data on the deflagration-to-detonation run-up distance for flowing mixtures of gasoline and air in 15.2-cm- (6.0-in.-) diameter piping simulating a vapor recovery system are presented. The quenching capability of eight selected flame control devices subjected to repeated stable detonations was evaluated. The successful detonation-flame arresters were: (1) spiral-wound, crimped aluminum ribbon, (2) foamed nickel-chrome metal, (3) vertically packed bed of aluminum Ballast rings, and (4) water-trap or hydraulic back-pressure valve. Installation configurations for two of the more applicable arresters, the spiral-wound, crimped stainless-steel ribbon and the vertically packed bed of aluminum Ballast rings, were further optimized by a series of parametric tests. The final configuration of these two arresters was demonstrated with repeated detonation tests at conditions that simulated vapor recovery system operation. On these tests, the combustible mixture of gasoline and air continued to flow through the piping for periods up to 120 seconds after the initial detonation had been arrested. There was no indication of continuous burning or reignition occurring on either side of the test arresters.

Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array

NASA Astrophysics Data System (ADS)

Zang, Arno; Stephansson, Ove; Stenberg, Leif; Plenkers, Katrin; Specht, Sebastian; Milkereit, Claus; Schill, Eva; Kwiatek, Grzegorz; Dresen, Georg; Zimmermann, Günter; Dahm, Torsten; Weber, Michael

2017-02-01

In this paper, an underground experiment at the Äspö Hard Rock Laboratory (HRL) is described. Main goal is optimizing geothermal heat exchange in crystalline rock mass at depth by multistage hydraulic fracturing with minimal impact on the environment, that is, seismic events. For this, three arrays with acoustic emission, microseismicity and electromagnetic sensors are installed mapping hydraulic fracture initiation and growth. Fractures are driven by three different water injection schemes (continuous, progressive and pulse pressurization). After a brief review of hydraulic fracture operations in crystalline rock mass at mine scale, the site geology and the stress conditions at Äspö HRL are described. Then, the continuous, single-flow rate and alternative, multiple-flow rate fracture breakdown tests in a horizontal borehole at depth level 410 m are described together with the monitoring networks and sensitivity. Monitoring results include the primary catalogue of acoustic emission hypocentres obtained from four hydraulic fractures with the in situ trigger and localizing network. The continuous versus alternative water injection schemes are discussed in terms of the fracture breakdown pressure, the fracture pattern from impression packer result and the monitoring at the arrays. An example of multistage hydraulic fracturing with several phases of opening and closing of fracture walls is evaluated using data from acoustic emissions, seismic broad-band recordings and electromagnetic signal response. Based on our limited amount of in situ tests (six) and evaluation of three tests in Ävrö granodiorite, in the multiple-flow rate test with progressively increasing target pressure, the acoustic emission activity starts at a later stage in the fracturing process compared to the conventional fracturing case with continuous water injection. In tendency, also the total number and magnitude of acoustic events are found to be smaller in the progressive treatment with frequent phases of depressurization.

Smart-actuated continuous moldline technology (CMT) mini wind tunnel test

NASA Astrophysics Data System (ADS)

Pitt, Dale M.; Dunne, James P.; Kilian, Kevin J.

1999-07-01

The Smart Aircraft and Marine Propulsion System Demonstration (SAMPSON) Program will culminate in two separate demonstrations of the application of Smart Materials and Structures technology. One demonstration will be for an aircraft application and the other for marine vehicles. The aircraft portion of the program will examine the application of smart materials to aircraft engine inlets which will deform the inlet in-flight in order to regulate the airflow rate into the engine. Continuous Moldline Technology (CMT), a load-bearing reinforced elastomer, will enable the use of smart materials in this application. The capabilities of CMT to withstand high-pressure subsonic and supersonic flows were tested in a sub-scale mini wind- tunnel. The fixture, used as the wind-tunnel test section, was designed to withstand pressure up to 100 psi. The top and bottom walls were 1-inch thick aluminum and the side walls were 1-inch thick LEXAN. High-pressure flow was introduced from the Boeing St. Louis poly-sonic wind tunnel supply line. CMT walls, mounted conformal to the upper and lower surfaces, were deflected inward to obtain a converging-diverging nozzle. The CMT walls were instrumented for vibration and deflection response. Schlieren photography was used to establish shock wave motion. Static pressure taps, embedded within one of the LEXAN walls, monitored pressure variation in the mini-wind tunnel. High mass flow in the exit region. This test documented the response of CMT technology in the presence of high subsonic flow and provided data to be used in the design of the SAMPSON Smart Inlet.

A continuous sampler with background suppression for monitoring alpha-emitting aerosol particles.

PubMed

McFarland, A R; Rodgers, J C; Ortiz, C A; Moore, M E

1992-05-01

A continuous air monitor has been developed that includes provisions for improving the detection of alpha-emitting aerosol particles in the presence of radon/thoron progeny that are unattached to ambient aerosol particles. Wind tunnel tests show that 80% of 10-microns aerodynamic equivalent diameter particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L min-1 (2 cfm) and the wind speed is 1 m s-1. Uniformity of aerosol collection on the filter, as characterized by the coefficient of variation of the areal density deposits, is less than 15% for 10-microns aerodynamic-equivalent-diameter aerosol particles. Tests with unattached radon daughters in a flow-through chamber showed that approximately 99% of the 218Po was removed by an inlet screen that is designed to collect radon daughters that are in the size range of molecular clusters. The inlet screen offers the opportunity to improve the signal-to-noise ratio of energy spectra in the regions of interest (subranges of the energy spectrum) of transuranic elements and thereby enhance the performance of background compensation algorithms.

Progress on a Rayleigh Scattering Mass Flux Measurement Technique

NASA Technical Reports Server (NTRS)

Mielke-Fagan, Amy F.; Clem, Michelle M.; Elam, Kristie A.; Hirt, Stefanie M.

2010-01-01

A Rayleigh scattering diagnostic has been developed to provide mass flux measurements in wind tunnel flows. Spectroscopic molecular Rayleigh scattering is an established flow diagnostic tool that has the ability to provide simultaneous density and velocity measurements in gaseous flows. Rayleigh scattered light from a focused 10 Watt continuous-wave laser beam is collected and fiber-optically transmitted to a solid Fabry-Perot etalon for spectral analysis. The circular interference pattern that contains the spectral information that is needed to determine the flow properties is imaged onto a CCD detector. Baseline measurements of density and velocity in the test section of the 15 cm x 15 cm Supersonic Wind Tunnel at NASA Glenn Research Center are presented as well as velocity measurements within a supersonic combustion ramjet engine isolator model installed in the tunnel test section.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, R.D.

This report discusses the progress achieved during the first year of a two year project entitled ''Well Test Performance and Analysis of Gas Wells Completed in Non-Continuous Lenticular Formations.'' The development of a general three dimensional dry gas reservoir simulator for non-continuous lenticular formations is presented. The simulator was used to perform well performance studies of real and hypothetical low permeability, lenticular, gas bearing formations indigeneous to the Rocky Mountain province of the United States. In addition a mathematical model is presented for simulating transient multiphase flow in a wellbore with phase re-distributions. Finally, an experimental research plan is outlinedmore » for measuring the non-Darcy flow coefficient in porous media and artifically fractured porous media. Conclusion are drawn and recommendations made concerning the continued pursuit of these research endeavors. 28 refs., 16 figs.« less

On continuous and discontinuous approaches for modeling groundwater flow in heterogeneous media using the Numerical Manifold Method: Model development and comparison

NASA Astrophysics Data System (ADS)

Hu, Mengsu; Wang, Yuan; Rutqvist, Jonny

2015-06-01

One major challenge in modeling groundwater flow within heterogeneous geological media is that of modeling arbitrarily oriented or intersected boundaries and inner material interfaces. The Numerical Manifold Method (NMM) has recently emerged as a promising method for such modeling, in its ability to handle boundaries, its flexibility in constructing physical cover functions (continuous or with gradient jump), its meshing efficiency with a fixed mathematical mesh (covers), its convenience for enhancing approximation precision, and its integration precision, achieved by simplex integration. In this paper, we report on developing and comparing two new approaches for boundary constraints using the NMM, namely a continuous approach with jump functions and a discontinuous approach with Lagrange multipliers. In the discontinuous Lagrange multiplier method (LMM), the material interfaces are regarded as discontinuities which divide mathematical covers into different physical covers. We define and derive stringent forms of Lagrange multipliers to link the divided physical covers, thus satisfying the continuity requirement of the refraction law. In the continuous Jump Function Method (JFM), the material interfaces are regarded as inner interfaces contained within physical covers. We briefly define jump terms to represent the discontinuity of the head gradient across an interface to satisfy the refraction law. We then make a theoretical comparison between the two approaches in terms of global degrees of freedom, treatment of multiple material interfaces, treatment of small area, treatment of moving interfaces, the feasibility of coupling with mechanical analysis and applicability to other numerical methods. The newly derived boundary-constraint approaches are coded into a NMM model for groundwater flow analysis, and tested for precision and efficiency on different simulation examples. We first test the LMM for a Dirichlet boundary and then test both LMM and JFM for an idealized heterogeneous model, comparing the numerical results with analytical solutions. Then we test both approaches for a heterogeneous model and compare the results of hydraulic head and specific discharge. We show that both approaches are suitable for modeling material boundaries, considering high accuracy for the boundary constraints, the capability to deal with arbitrarily oriented or complexly intersected boundaries, and their efficiency using a fixed mathematical mesh.

Initial stages of cavitation damage and erosion on copper and brass tested in a rotating disk device

NASA Technical Reports Server (NTRS)

Rao, P. V.; Rao, B. C. S.; Rao, N. S. L.

1982-01-01

In view of the differences in flow and experimental conditions, there has been a continuing debate as to whether or not the ultrasonic method of producing cavitation damage is similar to the damage occurring in cavitating flow systems, namely, venturi and rotating disk devices. In this paper, the progress of cavitation damage during incubation periods on polycrystalline copper and brass tested in a rotating disk device is presented. The results indicate several similarities and differences in the damage mechanism encountered in a rotating disk device (which simulates field rotary devices) and a magnetostriction apparatus. The macroscopic erosion appears similar to that in the vibratory device except for nonuniform erosion and apparent plastic flow during the initial damage phase.

An LDA (Laser-Doppler Anemometry) investigation of three-dimensional normal shock wave boundary-layer interactions

NASA Technical Reports Server (NTRS)

Chriss, R. M.; Hingst, W. R.; Strazisar, A. J.; Keith, T. G., Jr.

1989-01-01

Nonintrusive measurements were made of a normal shock wave/boundary layer interaction. Two dimensional measurements were made throughout the interaction region while 3-D measurements were made in the vicinity of the shock wave. The measurements were made in the corner of the test section of a continuous supersonic wind tunnel in which a normal shock wave had been stabilized. Laser Doppler Anemometry, surface pressure measurement and flow visualization techniques were employed for two freestream Mach number test cases: 1.6 and 1.3. The former contained separated flow regions and a system of shock waves. The latter was found to be far less complicated. The results define the flow field structure in detail for each case.

The NASA Langley 16-Foot Transonic Tunnel: Historical Overview, Facility Description, Calibration, Flow Characteristics, and Test Capabilities

NASA Technical Reports Server (NTRS)

Capone, Francis J.; Bangert, Linda S.; Asbury, Scott C.; Mills, Charles T. L.; Bare, E. Ann

1995-01-01

The Langley 16-Foot Transonic Tunnel is a closed-circuit single-return atmospheric wind tunnel that has a slotted octagonal test section with continuous air exchange. The wind tunnel speed can be varied continuously over a Mach number range from 0.1 to 1.3. Test-section plenum suction is used for speeds above a Mach number of 1.05. Over a period of some 40 years, the wind tunnel has undergone many modifications. During the modifications completed in 1990, a new model support system that increased blockage, new fan blades, a catcher screen for the first set of turning vanes, and process controllers for tunnel speed, model attitude, and jet flow for powered models were installed. This report presents a complete description of the Langley 16-Foot Transonic Tunnel and auxiliary equipment, the calibration procedures, and the results of the 1977 and the 1990 wind tunnel calibration with test section air removal. Comparisons with previous calibrations showed that the modifications made to the wind tunnel had little or no effect on the aerodynamic characteristics of the tunnel. Information required for planning experimental investigations and the use of test hardware and model support systems is also provided.

Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow conditions

NASA Astrophysics Data System (ADS)

Ren, Lijiao; Ahn, Yongtae; Hou, Huijie; Zhang, Fang; Logan, Bruce E.

2014-07-01

Power production of four hydraulically connected microbial fuel cells (MFCs) was compared with the reactors operated using individual electrical circuits (individual), and when four anodes were wired together and connected to four cathodes all wired together (combined), in fed-batch or continuous flow conditions. Power production under these different conditions could not be made based on a single resistance, but instead required polarization tests to assess individual performance relative to the combined MFCs. Based on the power curves, power produced by the combined MFCs (2.12 ± 0.03 mW, 200 Ω) was the same as the summed power (2.13 mW, 50 Ω) produced by the four individual reactors in fed-batch mode. With continuous flow through the four MFCs, the maximum power (0.59 ± 0.01 mW) produced by the combined MFCs was slightly lower than the summed maximum power of the four individual reactors (0.68 ± 0.02 mW). There was a small parasitic current flow from adjacent anodes and cathodes, but overall performance was relatively unaffected. These findings demonstrate that optimal power production by reactors hydraulically and electrically connected can be predicted from performance by individual reactors.

Study of thermal effects on nickel-cadmium batteries

NASA Technical Reports Server (NTRS)

Foley, R. T.; Webster, W. H.

1967-01-01

Isothermal continuous flow calorimeter is designed to test a nickel-cadmium battery under numerous orbital conditions. This sensitive calorimeter collects cell data such as oxygen pressure and rate of heat generation, and calculates changes in enthalpy.

Pressure Drop Across Woven Screens Under Uniform and Nonuniform Flow Conditions. [flow characteristics of water through Dutch twill and square weave fabrics

NASA Technical Reports Server (NTRS)

Ludewig, M.; Omori, S.; Rao, G. L.

1974-01-01

Tests were conducted to determine the experimental pressure drop and velocity data for water flowing through woven screens. The types of materials used are dutch twill and square weave fabrics. Pressure drop measures were made at four locations in a rectangular channel. The data are presented as change in pressure compared with the average entry velocity and the numerical relationship is determined by dividing the volumetric flow rate by the screen area open to flow. The equations of continuity and momentum are presented. A computer program listing an extension of a theoretical model and data from that computer program are included.

Carotid blood flow changes with behavioral states in the late gestation llama fetus in utero.

PubMed

Blanco, C E; Giussani, D A; Riquelme, R A; Hanson, M A; Llanos, A J

1997-12-19

This study tested the hypothesis that in the llama fetus changes in cerebral blood flow are closely associated with changes in cerebral oxidative metabolism such as occur during transitions between electrocortical states. For the first time reported in any species, instantaneous changes in common carotid blood flow, employed as a continuous index of cerebrovascular perfusion, were related to instantaneous changes in electrocortical activity. Three late gestation fetal llamas were surgically prepared under general anesthesia with vascular catheters, a tracheal and amniotic catheter, and with electrodes implanted to monitor the fetal electrocorticogram (ECoG). In addition, Transonic flow probes were placed around a common carotid artery and a femoral artery. At least 4 days after surgery fetal arterial blood, amniotic and tracheal pressures, carotid and femoral blood flows and the fetal ECoG were recorded continuously. Our results suggest a close association between increases in common carotid blood flow and low voltage ECoG in the llama fetus. Close coupling between instantaneous changes in carotid blood flow and electrocortical states together with the lack of an increase in brain blood flow without increased cerebral oxygen extraction during hypoxemia in the llama fetus supports a fall in cerebral oxidative metabolism in this species during hypoxemic episodes.

Milk flow rates from bottle nipples used after hospital discharge

PubMed Central

Pados, Britt Frisk; Park, Jinhee; Thoyre, Suzanne M.; Estrem, Hayley; Nix, W. Brant

2016-01-01

Purpose To test the milk flow rates and variability in flow rates of bottle nipples used after hospital discharge. Study Design and Methods Twenty-six nipple types that represented 15 common brands as well as variety in price per nipple and store location sold (e.g., Babies R’ Us, Walmart, Dollar Store) were chosen for testing. Ten of each nipple type (n=260 total) were tested by measuring the amount of infant formula expressed in one minute using a breast pump. Mean milk flow rate (mL/min) and coefficient of variation (CV) were calculated. Flow rates of nipples within brand were compared statistically. Results Milk flow rates varied from 1.68 mL/min for the Avent Natural Newborn Flow to 85.34 mL/min for the Dr. Brown’s Standard Y-cut. Variability between nipple types also varied widely, from .03 for the Dr. Brown’s Standard Level 3 to .37 for MAM Nipple 1 Slow Flow. Clinical Implications The extreme range of milk flow rates found may be significant for medically fragile infants being discharged home who are continuing to develop oral feeding skills. The name of the nipple does not provide clear information about the flow rate to guide parents in decision-making. Variability in flow rates within nipples of the same type may complicate oral feeding for the medically fragile infant who may not be able to adapt easily to change in flow rates. Both flow rate and variability should be considered when guiding parents to a nipple choice. PMID:27008466

Continuous-Flow Left Ventricular Assist Device Support Improves Myocardial Supply:Demand in Chronic Heart Failure.

PubMed

Soucy, Kevin G; Bartoli, Carlo R; Phillips, Dustin; Giridharan, Guruprasad A; Sobieski, Michael A; Wead, William B; Dowling, Robert D; Wu, Zhongjun J; Prabhu, Sumanth D; Slaughter, Mark S; Koenig, Steven C

2017-06-01

Continuous-flow left ventricular assist devices (CF LVADs) are rotary blood pumps that improve mean blood flow, but with potential limitations of non-physiological ventricular volume unloading and diminished vascular pulsatility. In this study, we tested the hypothesis that left ventricular unloading with increasing CF LVAD flow increases myocardial flow normalized to left ventricular work. Healthy (n = 8) and chronic ischemic heart failure (IHF, n = 7) calves were implanted with CF LVADs. Acute hemodynamics and regional myocardial blood flow were measured during baseline (LVAD off, clamped), partial (2-4 L/min) and full (>4 L/min) LVAD support. IHF calves demonstrated greater reduction of cardiac energy demand with increasing LVAD support compared to healthy calves, as calculated by rate-pressure product. Coronary artery flows (p < 0.05) and myocardial blood flow (left ventricle (LV) epicardium and myocardium, p < 0.05) decreased with increasing LVAD support in normal calves. In the IHF model, blood flow to the septum, LV, LV epicardium, and LV myocardium increased significantly with increasing LVAD support when normalized to cardiac energy demand (p < 0.05). In conclusion, myocardial blood flow relative to cardiac demand significantly increased in IHF calves, thereby demonstrating that CF LVAD unloading effectively improves cardiac supply and demand ratio in the setting of ischemic heart failure.

CATS, continuous automated testing of seismological, hydroacoustic, and infrasound (SHI) processing software.

NASA Astrophysics Data System (ADS)

Brouwer, Albert; Brown, David; Tomuta, Elena

2017-04-01

To detect nuclear explosions, waveform data from over 240 SHI stations world-wide flows into the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), located in Vienna, Austria. A complex pipeline of software applications processes this data in numerous ways to form event hypotheses. The software codebase comprises over 2 million lines of code, reflects decades of development, and is subject to frequent enhancement and revision. Since processing must run continuously and reliably, software changes are subjected to thorough testing before being put into production. To overcome the limitations and cost of manual testing, the Continuous Automated Testing System (CATS) has been created. CATS provides an isolated replica of the IDC processing environment, and is able to build and test different versions of the pipeline software directly from code repositories that are placed under strict configuration control. Test jobs are scheduled automatically when code repository commits are made. Regressions are reported. We present the CATS design choices and test methods. Particular attention is paid to how the system accommodates the individual testing of strongly interacting software components that lack test instrumentation.

Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

This paper presents results from an explanatory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered,more » focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected in the resulting steady-state analyses using NASA's FUN3D CFD software.« less

Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

NASA Technical Reports Server (NTRS)

Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

2016-01-01

This paper presents results from an exploratory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected and the resulting steady-state analyses using NASA's FUN3D CFD software.

Landscape genetics of a pollinator longhorn beetle [Typocerus v. velutinus (Olivier)] on a continuous habitat surface.

PubMed

Abdel Moniem, H E M; Schemerhorn, B J; DeWoody, J A; Holland, J D

2016-10-01

Landscape connectivity, the degree to which the landscape structure facilitates or impedes organismal movement and gene flow, is increasingly important to conservationists and land managers. Metrics for describing the undulating shape of continuous habitat surfaces can expand the usefulness of continuous gradient surfaces that describe habitat and predict the flow of organisms and genes. We adopted a landscape gradient model of habitat and used surface metrics of connectivity to model the genetic continuity between populations of the banded longhorn beetle [Typocerus v. velutinus (Olivier)] collected at 17 sites across a fragmentation gradient in Indiana, USA. We tested the hypothesis that greater habitat connectivity facilitates gene flow between beetle populations against a null model of isolation by distance (IBD). We used next-generation sequencing to develop 10 polymorphic microsatellite loci and genotype the individual beetles to assess the population genetic structure. Isolation by distance did not explain the population genetic structure. The surface metrics model of habitat connectivity explained the variance in genetic dissimilarities 30 times better than the IBD model. We conclude that surface metrology of habitat maps is a powerful extension of landscape genetics in heterogeneous landscapes. © 2016 John Wiley & Sons Ltd.

Velocity surveys in a turbine stator annular-cascade facility using laser Doppler techniques. [flow measurement and flow characteristics

NASA Technical Reports Server (NTRS)

Goldman, L. J.; Seasholtz, R. G.; Mclallin, K. L.

1976-01-01

A laser Doppler velocimeter (LDV) was used to determine the flow conditions downstream of an annular cascade of stator blades operating at an exit critical velocity ratio of 0.87. Two modes of LDV operation (continuous scan and discrete point) were investigated. Conventional pressure probe measurements were also made for comparison with the LDV results. Biasing errors that occur in the LDV measurement of velocity components were also studied. In addition, the effect of pressure probe blockage on the flow conditions was determined with the LDV. Photographs and descriptions of the test equipment used are given.

Space shuttle orbiter rear mounted reaction control system jet interaction study. [hypersonic wind tunnel tests

NASA Technical Reports Server (NTRS)

Rausch, J. R.

1977-01-01

The effect of interaction between the reaction control system (RCS) jets and the flow over the space shuttle orbiter in the atmosphere was investigated in the NASA Langley 31-inch continuous flow hypersonic tunnel at a nominal Mach number of 10.3 and in the AEDC continuous flow hypersonic tunnel B at a nominal Mach number of 6, using 0.01 and .0125 scale force models with aft RCS nozzles mounted both on the model and on the sting of the force model balance. The data show that RCS nozzle exit momentum ratio is the primary correlating parameter for effects where the plume impinges on an adjacent surface and mass flow ratio is the parameter when the plume interaction is primarily with the external stream. An analytic model of aft mounted RCS units was developed in which the total reaction control moments are the sum of thrust, impingement, interaction, and cross-coupling terms.

Continuous Passive Sampling of Solutes from Agricultural Subsurface Drainage Tubes

NASA Astrophysics Data System (ADS)

Lindblad Vendelboe, Anders; de Jonge, Hubert; Rozemeijer, Joachim; Wollesen de Jonge, Lis

2015-04-01

Agricultural subsurface tube drain systems play an important role in water and solute transport. One study, focusing on lowland agricultural catchments, showed that subsurface tube drainage contributed up to 80% of the annual discharge and 90% of the annual NO3 load from agricultural fields to the receiving water bodies. Knowledge of e.g. nutrient loads and drainage volumes, based on measurements and modelling, are important for adequate water quality management. Despite the importance of tube drain transport of solutes, monitoring data are scarce. This scarcity is a result of the existing monitoring techniques for flow and contaminant load from tube drains being expensive and labor-extensive. The study presented here aimed at developing a cheap, simple, and robust method to monitor solute loads from tube drains. The method is based on the newly developed Flowcap, which can be attached to existing tube drain outlets and can measure total flow, contaminant load and flow-averaged concentrations of solutes in the drainage. The Flowcap builds on the existing Sorbicell principle, a passive sampling system that measures average concentrations over longer periods of time (days to months) for various compounds. The Sorbicell consists of two compartments permeable to water. One compartment contains an adsorbent and one contains a tracer. When water passes through the Sorbicell the compound of interest is absorbed while a tracer is released. Using the tracer loss to calculate the volume of water that has passed the Sorbicell it is possible to calculate the average concentration of the compound. When mounting Sorbicells in the Flowcap, a flow-proportional part of the drainage is sampled from the main stream. To accommodate the wide range of drainage flow rates two Flowcaps with different capacities were tested in the laboratory: one with a capacity of 25 L min-1 (Q25) and one with a capacity of 256 L min-1 (Q256). In addition, Sorbicells with two different hydraulic resistances were tested, again to accommodate a large range of potential drainage flows rates. The experiment was continued until the Sorbicell's capacity was exhausted, which gave experimentation times from 6 to 34 days, while continuously changing the drainage flow rate to simulate field drainage conditions, and to test the range of the Flowcap. The laboratory testing yielded a very good linear correlation between drainage flow rates and Sorbicell sampling rates, giving r = 0.99 for both the Q25 and the Q256 Flowcap. The Sorbicells in this experiment were designed to measure NO3, but the Flowcap can be used with any Sorbicell and thus be used to measure any compound of interest. The Flowcap does not need housing, electricity, or maintenance and continuously register drainage volumes and contaminant loads for periods up to one month. This, in addition to the low cost of the monitoring system, enables large-scale monitoring of contaminant loads via tube drains, giving valuable data for the improvement of contaminant transport models. Further, these data will help select and evaluate the different mitigation option to improve water quality.

A Fully Magnetically Levitated Circulatory Pump for Advanced Heart Failure.

PubMed

Mehra, Mandeep R; Naka, Yoshifumi; Uriel, Nir; Goldstein, Daniel J; Cleveland, Joseph C; Colombo, Paolo C; Walsh, Mary N; Milano, Carmelo A; Patel, Chetan B; Jorde, Ulrich P; Pagani, Francis D; Aaronson, Keith D; Dean, David A; McCants, Kelly; Itoh, Akinobu; Ewald, Gregory A; Horstmanshof, Douglas; Long, James W; Salerno, Christopher

2017-02-02

Continuous-flow left ventricular assist systems increase the rate of survival among patients with advanced heart failure but are associated with the development of pump thrombosis. We investigated the effects of a new magnetically levitated centrifugal continuous-flow pump that was engineered to avert thrombosis. We randomly assigned patients with advanced heart failure to receive either the new centrifugal continuous-flow pump or a commercially available axial continuous-flow pump. Patients could be enrolled irrespective of the intended goal of pump support (bridge to transplantation or destination therapy). The primary end point was a composite of survival free of disabling stroke (with disabling stroke indicated by a modified Rankin score >3; scores range from 0 to 6, with higher scores indicating more severe disability) or survival free of reoperation to replace or remove the device at 6 months after implantation. The trial was powered for noninferiority testing of the primary end point (noninferiority margin, -10 percentage points). Of 294 patients, 152 were assigned to the centrifugal-flow pump group and 142 to the axial-flow pump group. In the intention-to-treat population, the primary end point occurred in 131 patients (86.2%) in the centrifugal-flow pump group and in 109 (76.8%) in the axial-flow pump group (absolute difference, 9.4 percentage points; 95% lower confidence boundary, -2.1 [P<0.001 for noninferiority]; hazard ratio, 0.55; 95% confidence interval [CI], 0.32 to 0.95 [two-tailed P=0.04 for superiority]). There were no significant between-group differences in the rates of death or disabling stroke, but reoperation for pump malfunction was less frequent in the centrifugal-flow pump group than in the axial-flow pump group (1 [0.7%] vs. 11 [7.7%]; hazard ratio, 0.08; 95% CI, 0.01 to 0.60; P=0.002). Suspected or confirmed pump thrombosis occurred in no patients in the centrifugal-flow pump group and in 14 patients (10.1%) in the axial-flow pump group. Among patients with advanced heart failure, implantation of a fully magnetically levitated centrifugal-flow pump was associated with better outcomes at 6 months than was implantation of an axial-flow pump, primarily because of the lower rate of reoperation for pump malfunction. (Funded by St. Jude Medical; MOMENTUM 3 ClinicalTrials.gov number, NCT02224755 .).

Improving hemodynamics of cardiovascular system under a novel intraventricular assist device support via modeling and simulations.

PubMed

Zhu, Shidong; Luo, Lin; Yang, Bibo; Li, Xinghui; Wang, Xiaohao

2017-12-01

Ventricular assist devices (LVADs) are increasingly recognized for supporting blood circulation in heart failure patients who are non-transplant eligible. Because of its volume, the traditional pulsatile device is not easy to implant intracorporeally. Continuous flow LVADs (CF-LVADs) reduce arterial pulsatility and only offer continuous flow, which is different from physiological flow, and may cause long-term complications in the cardiovascular system. The aim of this study was to design a new pulsatile assist device that overcomes this disadvantage, and to test this device in the cardiovascular system. Firstly, the input and output characteristics of the new device were tested in a simple cardiovascular mock system. A detailed mathematical model was established by fitting the experimental data. Secondly, the model was tested in four pathological cases, and was simulated and coupled with a fifth-order cardiovascular system and a new device model using Matlab software. Using assistance of the new device, we demonstrated that the left ventricle pressure, aortic pressure, and aortic flow of heart failure patients improved to the levels of a healthy individual. Especially, in state IV level heart failure patients, the systolic blood pressure increased from 81.34 mmHg to 132.1 mmHg, whereas the diastolic blood pressure increased from 54.28 mmHg to 78.7 mmHg. Cardiac output increased from 3.21 L/min to 5.16 L/min. The newly-developed assist device not only provided a physiological flow that was similar to healthy individuals, but also effectively improved the ability of the pathological ventricular volume. Finally, the effects of the new device on other hemodynamic parameters are discussed.

Optic nerve head blood flow response to reduced ocular perfusion pressure by alteration of either the blood pressure or intraocular pressure.

PubMed

Wang, Lin; Cull, Grant A; Fortune, Brad

2015-04-01

To test the hypothesis that blood flow autoregulation in the optic nerve head has less reserve to maintain normal blood flow in the face of blood pressure-induced ocular perfusion pressure decrease than a similar magnitude intraocular pressure-induced ocular perfusion pressure decrease. Twelve normal non-human primates were anesthetized by continuous intravenous infusion of pentobarbital. Optic nerve blood flow was monitored by laser speckle flowgraphy. In the first group of animals (n = 6), the experimental eye intraocular pressure was maintained at 10 mmHg using a saline reservoir connected to the anterior chamber. The blood pressure was gradually reduced by a slow injection of pentobarbital. In the second group (n = 6), the intraocular pressure was slowly increased from 10 mmHg to 50 mmHg by raising the reservoir. In both experimental groups, optic nerve head blood flow was measured continuously. The blood pressure and intraocular pressure were simultaneously recorded in all experiments. The optic nerve head blood flow showed significant difference between the two groups (p = 0.021, repeat measures analysis of variance). It declined significantly more in the blood pressure group compared to the intraocular pressure group when the ocular perfusion pressure was reduced to 35 mmHg (p < 0.045) and below. There was also a significant interaction between blood flow changes and the ocular perfusion pressure treatment (p = 0.004, adjusted Greenhouse & Geisser univariate test), indicating the gradually enlarged blood flow difference between the two groups was due to the ocular perfusion pressure decrease. The results show that optic nerve head blood flow is more susceptible to an ocular perfusion pressure decrease induced by lowering the blood pressure compared with that induced by increasing the intraocular pressure. This blood flow autoregulation capacity vulnerability to low blood pressure may provide experimental evidence related to the hemodynamic pathophysiology in glaucoma.

Ignition Characterization Tests of the LOX/Ethanol Propellant Combination

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Robinson, Philip J.; Veith, Eric M.

2004-01-01

A series of contracts have been issued by the Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) to explore candidate technologies considered to be important for the Next Generation Launch Technology (NGLT) effort. One aspect of the NGLT effort is to explore the potential of incorporating non-toxic propellants for Reaction Control Subsystems (RCS). Contract NAS8-01109 has been issued to Aerojet to develop a dual thrust Reaction Control Engine (RCE) that utilizes liquid oxygen and ethanol as the propellants. The dual thrust RCE incorporates a primary thrust level of 870 lbf, and a vernier thrust level of 10 - 30 lbf. Aerojet has designed and tested a workhorse LOX igniter to determine LOX/Ethanol ignition characteristics as part of a risk mitigation effort for the dual thrust RCE design. The objective of the ignition testing was to demonstrate successfid ignition from GOX to LOX, encompassing potential two-phase flow conditions. The workhorse igniter was designed to accommodate the full LOX design flowrate, as well as a reduced GOX flowrate. It was reasoned that the initial LOX flow through the igniter would flash to GOX due to the inherent heat stored in the hardware, causing a reduced oxygen flowrate because of a choked, or sonic, flow condition through the injection elements. As LOX flow continued, the inherent heat of the test hardware would be removed and the hardware would chill-in, with the injected oxygen flow transitioning from cold GOX through two-phase flow to subcooled LOX. Pressure and temperature instrumentation permitted oxygen state points to be determined, and gas-side igniter chamber thermocouples provided chamber thermal profile characteristics. The cold flow chamber pressure (P(sub c)) for each test was determined and coupled with the igniter chamber diameter (D(sub c)) to calculate the characteristic quench parameter (P(sub c) x D(sub c)), which was plotted as a function of core mixture ratio, MR(sub c). Ignition limits were determined over a broad range of valve inlet conditions, and ignition was demonstrated with oxygen inlet conditions that ranged from subcooled 173 R LOX to 480 R GQX. Once ignited at cold GOX conditions, combustion was continuous as the hardware chilled in and the core mixture ratio transitioned from values near 1.0 to over 12.5.

River Induced Wellbore Flow Dynamics in Long-Screen Wells and their Impact on Aqueous Sampling Results

NASA Astrophysics Data System (ADS)

Vermeul, V.; McKinley, J. P.; Newcomer, D.; Fritz, B. G.; Mackley, R.; Zachara, J. M.

2010-12-01

Previously published field investigations and modeling studies have demonstrated the potential for sample bias associated with vertical wellbore flow in conventional monitoring wells constructed with long-screened intervals. In this study, simultaneous measurement of 1) wellbore flow using an electromagnetic borehole flowmeter (EBF), 2) depth discrete hydraulic head, and 3) aqueous uranium concentrations were used to quantify wellbore flow and assess the associated impacts on measured aqueous concentrations. Monitoring results demonstrate the utility of continuous (i.e., hourly measurements for ~ one month) ambient wellbore flow monitoring and show that relatively large wellbore flows (up to 4 LPM) can be induced by aquifer hydrodynamics associated with a fluctuating river boundary located approximately 250 m from the test well. The observed vertical wellbore flows were strongly correlated with fluctuations in river stage, alternating between upward and downward flow throughout the monitoring period in response to changes in river stage. Continuous monitoring of ambient wellbore flows using an EBF system allowed these effects to be evaluated in concert with continuously monitored river stage elevations (hourly) and aqueous uranium concentrations (daily) in a long-screen well and an adjacent multi-level well cluster. This study demonstrates that when contaminant concentrations within the aquifer vary significantly over the depth interval interrogated, river-induced vertical wellbore flow can result in variations in measured concentration that nearly encompass the full range of variation in aquifer contaminant concentration with depth. In addition, observed variability in aqueous concentrations measured during active tracer transport experiments provided additional evidence of wellbore flow impacts and showed that the magnitude and direction of wellbore flow varied spatially across the wellfield. An approach to mitigate these effects based on increasing hydraulic resistance within the wellbore was evaluated. This research is part of the ERSP Hanford IFRC at Pacific Northwest National Laboratory.

Application of DPIV to Enhanced Mixing Heated Nozzle Flows

NASA Technical Reports Server (NTRS)

Wernet, Mark P.; Bridges, James

2002-01-01

Digital Particle Imaging Velocimetry (DPIV) is a planar velocity measurement technique that continues to be applied to new and challenging engineering research facilities while significantly reducing facility test time. DPIV was used in the GRC Nozzle Acoustic Test Rig (NATR) to characterize the high temperature (560 C), high speed (is greater than 500 m/s) flow field properties of mixing enhanced jet engine nozzles. The instantaneous velocity maps obtained using DPIV were used to determine mean velocity, rms velocity and two-point correlation statistics to verify the true turbulence characteristics of the flow. These measurements will ultimately be used to properly validate aeroacoustic model predictions by verifying CFD input to these models. These turbulence measurements have previously not been possible in hot supersonic jets. Mapping the nozzle velocity field using point based techniques requires over 60 hours of test time, compared to less than 45 minutes using DPIV, yielding a significant reduction in testing time. A dual camera DPIV configuration was used to maximize the field of view and further minimize the testing time required to map the nozzle flow. The DPIV system field of view covered 127 by 267 mm. Data were acquired at 19 axial stations providing coverage of the flow from the nozzle exit to 2.37 in downstream. At each measurement station, 400 image frame pairs were acquired from each camera. The DPIV measurements of the mixing enhanced nozzle designs illustrate the changes in the flow field resulting in the reduced noise signature.

Combined effects of hydrazine exposure and endurance testing on solenoid-actuated valve performance

NASA Technical Reports Server (NTRS)

Hagler, R., Jr.

1974-01-01

Results are presented from a test program which was conducted to assess the capability of various solenoid-actuated valve design concepts to provide performance characteristics commensurate with long-duration (ten-year) missions to explore the outer planets. The valves were installed in a hydrazine flow test setup and periodically cycled during a nine-month test period under test conditions comparable to anticipated mission operating conditions. In situ valve performance was periodically determined, and leakage was continuously monitored.

Guidelines for Calculating and Routing a Dam-Break Flood.

DTIC Science & Technology

1977-01-01

flow, Teton Dam . 20. ABSTRACT (Continue an reverse aide If necessary and Identify by block number) This report described procedures necessary to calculate...and route a dam -break flood using an existing generalized unsteady open channel flow model. The recent Teton Dam event was reconstituted to test the...methodology may be obtained from The Hydrologic Engineering Center. The computer program was applied to the Teton Dam data set to demonstrate the level of

Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.

PubMed

Kasahara, Masataka; Ichinohe, Tatsuya; Okamoto, Sota; Okada, Reina; Kanbe, Hiroaki; Matsuura, Nobuyuki

2015-06-01

To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia. Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min. Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values. Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.

Calibration of the NASA Glenn 8- by 6-Foot Supersonic Wind Tunnel (1996 and 1997 Tests)

NASA Technical Reports Server (NTRS)

Arrington, E. Allen

2012-01-01

There were several physical and operational changes made to the NASA Glenn Research Center 8- by 6-Foot Supersonic Wind Tunnel during the period of 1992 through 1996. Following each of these changes, a facility calibration was conducted to provide the required information to support the research test programs. Due to several factors (facility research test schedule, facility downtime and continued facility upgrades), a full test section calibration was not conducted until 1996. This calibration test incorporated all test section configurations and covered the existing operating range of the facility. However, near the end of that test entry, two of the vortex generators mounted on the compressor exit tailcone failed causing minor damage to the honeycomb flow straightener. The vortex generators were removed from the facility and calibration testing was terminated. A follow-up test entry was conducted in 1997 in order to fully calibrate the facility without the effects of the vortex generators and to provide a complete calibration of the newly expanded low speed operating range. During the 1997 tunnel entry, all planned test points required for a complete test section calibration were obtained. This data set included detailed in-plane and axial flow field distributions for use in quantifying the test section flow quality.

Amine-Functionalized Sugarcane Bagasse: A Renewable Catalyst for Efficient Continuous Flow Knoevenagel Condensation Reaction at Room Temperature.

PubMed

Qiao, Yanhui; Teng, Junjiang; Wang, Shuangfei; Ma, Hao

2017-12-24

A biomass-based catalyst with amine groups (-NH₂), viz., amine-functionalized sugarcane bagasse (SCB-NH₂), was prepared through the amination of sugarcane bagasse (SCB) in a two-step process. The physicochemical properties of the catalyst were characterized through FT-IR, elemental analysis, XRD, TG, and SEM-EDX techniques, which confirmed the -NH₂ group was grafted onto SCB successfully. The catalytic performance of SCB-NH₂ in Knoevenagel condensation reaction was tested in the batch and continuous flow reactions. Significantly, it was found that the catalytic performance of SCB-NH₂ is better in flow system than that in batch system. Moreover, the SCB-NH₂ presented an excellent catalytic activity and stability at the high flow rate. When the flow rate is at the 1.5 mL/min, no obvious deactivation was observed and the product yield and selectivity are more than 97% and 99% after 80 h of continuous reaction time, respectively. After the recovery of solvent from the resulting solution, a white solid was obtained as a target product. As a result, the SCB-NH₂ is a promising catalyst for the synthesis of fine chemicals by Knoevenagel condensation reaction in large scale, and the modification of the renewable SCB with -NH₂ group is a potential avenue for the preparation of amine-functionalized catalytic materials in industry.

The hydrodynamic basis of the vacuum cleaner effect in continuous-flow PCNL instruments: an empiric approach and mathematical model.

PubMed

Mager, R; Balzereit, C; Gust, K; Hüsch, T; Herrmann, T; Nagele, U; Haferkamp, A; Schilling, D

2016-05-01

Passive removal of stone fragments in the irrigation stream is one of the characteristics in continuous-flow PCNL instruments. So far the physical principle of this so-called vacuum cleaner effect has not been fully understood yet. The aim of the study was to empirically prove the existence of the vacuum cleaner effect and to develop a physical hypothesis and generate a mathematical model for this phenomenon. In an empiric approach, common low-pressure PCNL instruments and conventional PCNL sheaths were tested using an in vitro model. Flow characteristics were visualized by coloring of irrigation fluid. Influence of irrigation pressure, sheath diameter, sheath design, nephroscope design and position of the nephroscope was assessed. Experiments were digitally recorded for further slow-motion analysis to deduce a physical model. In each tested nephroscope design, we could observe the vacuum cleaner effect. Increase in irrigation pressure and reduction in cross section of sheath sustained the effect. Slow-motion analysis of colored flow revealed a synergism of two effects causing suction and transportation of the stone. For the first time, our model showed a flow reversal in the sheath as an integral part of the origin of the stone transportation during vacuum cleaner effect. The application of Bernoulli's equation provided the explanation of these effects and confirmed our experimental results. We widen the understanding of PCNL with a conclusive physical model, which explains fluid mechanics of the vacuum cleaner effect.

Jet-Surface Interaction Test: Flow Measurements Results

NASA Technical Reports Server (NTRS)

Brown, Cliff; Wernet, Mark

2014-01-01

Modern aircraft design often puts the engine exhaust in close proximity to the airframe surfaces. Aircraft noise prediction tools must continue to develop in order to meet the challenges these aircraft present. The Jet-Surface Interaction Tests have been conducted to provide a comprehensive quality set of experimental data suitable for development and validation of these exhaust noise prediction methods. Flow measurements have been acquired using streamwise and cross-stream particle image velocimetry (PIV) and fluctuating surface pressure data acquired using flush mounted pressure transducers near the surface trailing edge. These data combined with previously reported far-field and phased array noise measurements represent the first step toward the experimental data base. These flow data are particularly applicable to development of noise prediction methods which rely on computational fluid dynamics to uncover the flow physics. A representative sample of the large flow data set acquired is presented here to show how a surface near a jet affects the turbulent kinetic energy in the plume, the spatial relationship between the jet plume and surface needed to generate surface trailing-edge noise, and differences between heated and unheated jet flows with respect to surfaces.

Modeling of the flow behavior of SAE 8620H combing microstructure evolution in hot forming

NASA Astrophysics Data System (ADS)

Fu, Xiaobin; Wang, Baoyu; Tang, Xuefeng

2017-10-01

With the development of net-shape forming technology, hot forming process is widely applied to manufacturing gear parts, during which, materials suffer severe plastic distortion and microstructure changes continually. In this paper, to understand and model the flow behavior and microstructure evolution, SAE 8620H, a widely used gear steel, is selected as the object and the flow behavior and microstructure evolution are observed by an isothermal hot compression tests at 1273-1373 K with a strain rate of 0.1-10 s-1. Depending on the results of the compression test, a set of internal-state-variable based unified constitutive equations is put forward to describe the flow behavior and microstructure evaluation of SAE 8620H. Moreover, the evaluation of the dislocation density and the fraction of dynamic recrystallization based on the theory of thermal activation is modeled and reincorporated into the constitutive law. The material parameters in the constitutive model are calculated based on the measured flow stress and dynamic recrystallization fraction. The predicted flow stress under different deformation conditions has a good agreement with the measured results.

Isothermal gas-liquid flow at reduced gravity

NASA Technical Reports Server (NTRS)

Dukler, A. E.

1990-01-01

Research on adiabatic gas-liquid flows under reduced gravity condition is presented together with experimental data obtained using a NASA-Lewis RC 100-ft drop tower and in a LeRC Learjet. It is found that flow patterns and characteristics remain unchanged after the first 1.5 s into microgravity conditions and that the calculated time for a continuity wave to traverse the test section is less than 1.2 s. It is also found that the dispersed bubbles move at the same velocity as that of the front of the slug and that the transition between bubbly and slug flow is insensitive to diameter. Both the bubbly and the slug flows are suggested to represent a continuum of the same physical process. The characteristics of annular, slug, and bubbly flows are compared.

Thermal Response to High-Power Holmium Laser Lithotripsy.

PubMed

Aldoukhi, Ali H; Ghani, Khurshid R; Hall, Timothy L; Roberts, William W

2017-12-01

The aim of this study was to investigate "caliceal" fluid temperature changes during holmium laser activation/lithotripsy using settings up to 40 W power output with different irrigation flow rates. The experimental system consisted of a glass test tube (diameter 10 mm/length 75 mm) filled with deionized water, to mimic a calix. Real-time temperature was recorded using a thermocouple (Physitemp, NJ) positioned 5 mm from the bottom of the tube. A 200 μm laser fiber (Flexiva; Boston Scientific, MA) was introduced through the working channel of a disposable ureteroscope (LithoVue; Boston Scientific) and the laser fiber tip was positioned 15 mm above the bottom of the test tube. Deionized water irrigation (room temperature) through the working channel of the ureteroscope was delivered at flow rates of 0, 7-8, 14-15, and 38-40 mL/minute. A 120-W holmium laser (pulse 120; Lumenis, CA) was used. The following settings were explored: 0.5 J × 10 Hz, 1.0 J × 10 Hz, 0.5 J × 20 Hz, 1.0 J × 20 Hz, 0.5 J × 40 Hz, 1.0 J × 40 Hz, and 0.5 J × 80 Hz. During each experiment, the laser was activated continuously for 60 seconds. Temperature increased with increasing laser power output and decreasing irrigation flow rate. The highest temperature, 70.3°C (standard deviation 2.7), occurred with laser setting of 1.0 J × 40 Hz and no irrigation after 60 seconds of continuous laser firing. None of the tested laser settings and irrigation parameters produced temperature exceeding 51°C when activated for only 10 seconds of continuous laser firing. High-power holmium settings fired in long bursts with low irrigation flow rates can generate high fluid temperatures in a laboratory "caliceal" model. Awareness of this risk allows urologist to implement a variety of techniques (higher irrigation flow rates, intermittent laser activation, and potentially cooled irrigation fluid) to control and mitigate thermal effects during holmium laser lithotripsy.

Synthesis of Geraniol Esters in a Continuous-Flow Packed-Bed Reactor of Immobilized Lipase: Optimization of Process Parameters and Kinetic Modeling.

PubMed

Salvi, Harshada M; Kamble, Manoj P; Yadav, Ganapati D

2018-02-01

With increasing demand for perfumes, flavors, beverages, and pharmaceuticals, the various associated industries are resorting to different approaches to enhance yields of desired compounds. The use of fixed-bed biocatalytic reactors in some of the processes for making fine chemicals will be of great value because the reaction times could be reduced substantially as well as high conversion and yields obtained. In the current study, a continuous-flow packed-bed reactor of immobilized Candida antarctica lipase B (Novozym 435) was employed for synthesis of various geraniol esters. Optimization of process parameters such as biocatalyst screening, effect of solvent, mole ratio, temperature and acyl donors was studied in a continuous-flow packed-bed reactor. Maximum conversion of ~ 87% of geranyl propionate was achieved in 15 min residence time at 70 °C using geraniol and propionic acid with a 1:1 mol ratio. Novozym 435 was found to be the most active and stable biocatalyst among all tested. Ternary complex mechanism with propionic acid inhibition was found to fit the data.

LSA Large Area Silicon Sheet Task Continuous Czochralski Process Development

NASA Technical Reports Server (NTRS)

Rea, S. N.

1979-01-01

A commercial Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a small, in-situ premelter with attendant silicon storage and transport mechanisms. Using a vertical, cylindrical graphite heater containing a small fused quartz test tube linear from which the molten silicon flowed out the bottom, approximately 83 cm of nominal 5 cm diamter crystal was grown with continuous melt addition furnished by the test tube premelter. High perfection crystal was not obtained, however, due primarily to particulate contamination of the melt. A major contributor to the particulate problem was severe silicon oxide buildup on the premelter which would ultimately drop into the primary melt. Elimination of this oxide buildup will require extensive study and experimentation and the ultimate success of continuous Czochralski depends on a successful solution to this problem. Economically, the continuous Czochralski meets near-term cost goals for silicon sheet material.

A thermally regenerative ammonia battery with carbon-silver electrodes for converting low-grade waste heat to electricity

NASA Astrophysics Data System (ADS)

Rahimi, Mohammad; Kim, Taeyoung; Gorski, Christopher A.; Logan, Bruce E.

2018-01-01

Thermally regenerative ammonia batteries (TRABs) have shown great promise as a method to convert low-grade waste heat into electrical power, with power densities an order of magnitude higher than other approaches. However, previous TRABs based on copper electrodes suffered from unbalanced anode dissolution and cathode deposition rates during discharging cycles, limiting practical applications. To produce a TRAB with stable and reversible electrode reactions over many cycles, inert carbon electrodes were used with silver salts. In continuous flow tests, power production was stable over 100 discharging cycles, demonstrating excellent reversibility. Power densities were 23 W m-2-electrode area in batch tests, which was 64% higher than that produced in parallel tests using copper electrodes, and 30 W m-2 (net energy density of 490 Wh m-3-anolyte) in continuous flow tests. While this battery requires the use a precious metal, an initial economic analysis of the system showed that the cost of the materials relative to energy production was 220 per MWh, which is competitive with energy production from other non-fossil fuel sources. A substantial reduction in costs could be obtained by developing less expensive anion exchange membranes.

Microgravity Flame Spread in Exploration Atmospheres: Pressure, Oxygen, and Velocity Effects on Opposed and Concurrent Flame Spread

NASA Technical Reports Server (NTRS)

Olson, Sandra L.; Ruff, Gary A.; Fletcher, J. Miller

2008-01-01

Microgravity tests of flammability and flame spread were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows. Three thin fuels were tested for flammability (Ultem 1000 (General Electric Company), 10 mil film, Nomex (Dupont) HT90-40, and Mylar G (Dupont) and one fuel for flame spread testing (Kimwipes (Kimberly-Clark Worldwide, Inc.). The 1g Upward Limiting Oxygen Index (ULOI) and 1g Maximum Oxygen Concentration (MOC) are found to be greater than those in 0g, by up to 4% oxygen mole fraction, meaning that the fuels burned in 0g at lower oxygen concentrations than they did using the NASA Standard 6001 Test 1 protocol. Flame spread tests with Kimwipes were used to develop correlations that capture the effects of flow velocity, oxygen concentration, and pressure on flame spread rate. These correlations were used to determine that over virtually the entire range of spacecraft atmospheres and flow conditions, the opposed spread is faster, especially for normoxic atmospheres. The correlations were also compared with 1g MOC for various materials as a function of pressure and oxygen. The lines of constant opposed flow agreed best with the 1g MOC trends, which indicates that Test 1 limits are essentially dictated by the critical heat flux for ignition. Further evaluation of these and other materials is continuing to better understand the 0g flammability of materials and its effect on the oxygen margin of safety.

Microdevice for plasma separation from whole human blood using bio-physical and geometrical effects

NASA Astrophysics Data System (ADS)

Tripathi, Siddhartha; Kumar, Y. V. Balavarun; Agrawal, Amit; Prabhakar, Amit; Joshi, Suhas S.

2016-06-01

In this research work, we present a simple and efficient passive microfluidic device for plasma separation from pure blood. The microdevice has been fabricated using conventional photolithography technique on a single layer of polydimethylsiloxane, and has been extensively tested on whole blood and enhanced (upto 62%) hematocrit levels of human blood. The microdevice employs elevated dimensions of about 100 μm such elevated dimensions ensure clog-free operation of the microdevice and is relatively easy to fabricate. We show that our microdevice achieves almost 100% separation efficiency on undiluted blood in the flow rate range of 0.3 to 0.5 ml/min. Detailed biological characterization of the plasma obtained from the microdevice is carried out by testing: proteins by ultra-violet spectrophotometric method, hCG (human chorionic gonadotropin) hormone, and conducting random blood glucose test. Additionally, flow cytometry study has also been carried on the separated plasma. These tests attest to the high quality of plasma recovered. The microdevice developed in this work is an outcome of extensive experimental research on understanding the flow behavior and separation phenomenon of blood in microchannels. The microdevice is compact, economical and effective, and is particularly suited in continuous flow operations.

Pretest Predictions for Ventilation Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Y. Sun; H. Yang; H.N. Kalia

The objective of this calculation is to predict the temperatures of the ventilating air, waste package surface, concrete pipe walls, and insulation that will be developed during the ventilation tests involving various test conditions. The results will be used as input to the following three areas: (1) Decisions regarding testing set-up and performance. (2) Assessing how best to scale the test phenomena measured. (3) Validating numerical approach for modeling continuous ventilation. The scope of the calculation is to identify the physical mechanisms and parameters related to thermal response in the ventilation tests, and develop and describe numerical methods that canmore » be used to calculate the effects of continuous ventilation. Sensitivity studies to assess the impact of variation of linear power densities (linear heat loads) and ventilation air flow rates are included. The calculation is limited to thermal effect only.« less

Design and performance of a new continuous-flow sample-introduction system for flame infrared-emission spectrometry: Applications in process analysis, flow injection analysis, and ion-exchange high-performance liquid chromatography.

PubMed

Lam, C K; Zhang, Y; Busch, M A; Busch, K W

1993-06-01

A new sample introduction system for the analysis of continuously flowing liquid streams by flame infrared-emission (FIRE) spectrometry has been developed. The system uses a specially designed purge cell to strip dissolved CO(2) from solution into a hydrogen gas stream that serves as the fuel for a hydrogen/air flame. Vibrationally excited CO(2) molecules present in the flame are monitored with a simple infrared filter (4.4 mum) photometer. The new system can be used to introduce analytes as a continuous liquid stream (process analysis mode) or on a discrete basis by sample injection (flow injection analysis mode). The key to the success of the method is the new purge-cell design. The small internal volume of the cell minimizes problems associated with purge-cell clean-out and produces sharp, reproducible signals. Spent analytical solution is continuously drained from the cell, making cell disconnection and cleaning between samples unnecessary. Under the conditions employed in this study, samples could be analyzed at a maximum rate of approximately 60/h. The new sample introduction system was successfully tested in both a process analysis- and a flow injection analysis mode for the determination of total inorganic carbon in Waco tap water. For the first time, flame infrared-emission spectrometry was successfully extended to non-volatile organic compounds by using chemical pretreatment with peroxydisulfate in the presence of silver ion to convert the analytes into dissolved carbon dioxide, prior to purging and detection by the FIRE radiometer. A test of the peroxydisulfate/Ag(+) reaction using six organic acids and five sugars indicated that all 11 compounds were oxidized to nearly the same extent. Finally, the new sample introduction system was used in conjunction with a simple filter FIRE radiometer as a detection system in ion-exchange high-performance liquid chromatography. Ion-exchange chromatograms are shown for two aqueous mixtures, one containing six organic acids and the second containing six mono-, di-, and trisaccharides.

Bayes to the Rescue: Continuous Positive Airway Pressure Has Less Mortality Than High-Flow Oxygen.

PubMed

Modesto I Alapont, Vicent; Khemani, Robinder G; Medina, Alberto; Del Villar Guerra, Pablo; Molina Cambra, Alfred

2017-02-01

The merits of high-flow nasal cannula oxygen versus bubble continuous positive airway pressure are debated in children with pneumonia, with suggestions that randomized controlled trials are needed. In light of a previous randomized controlled trial showing a trend for lower mortality with bubble continuous positive airway pressure, we sought to determine the probability that a new randomized controlled trial would find high-flow nasal cannula oxygen superior to bubble continuous positive airway pressure through a "robust" Bayesian analysis. Sample data were extracted from the trial by Chisti et al, and requisite to "robust" Bayesian analysis, we specified three prior distributions to represent clinically meaningful assumptions. These priors (reference, pessimistic, and optimistic) were used to generate three scenarios to represent the range of possible hypotheses. 1) "Reference": we believe bubble continuous positive airway pressure and high-flow nasal cannula oxygen are equally effective with the same uninformative reference priors; 2) "Sceptic on high-flow nasal cannula oxygen": we believe that bubble continuous positive airway pressure is better than high-flow nasal cannula oxygen (bubble continuous positive airway pressure has an optimistic prior and high-flow nasal cannula oxygen has a pessimistic prior); and 3) "Enthusiastic on high-flow nasal cannula oxygen": we believe that high-flow nasal cannula oxygen is better than bubble continuous positive airway pressure (high-flow nasal cannula oxygen has an optimistic prior and bubble continuous positive airway pressure has a pessimistic prior). Finally, posterior empiric Bayesian distributions were obtained through 100,000 Markov Chain Monte Carlo simulations. In all three scenarios, there was a high probability for more death from high-flow nasal cannula oxygen compared with bubble continuous positive airway pressure (reference, 0.98; sceptic on high-flow nasal cannula oxygen, 0.982; enthusiastic on high-flow nasal cannula oxygen, 0.742). The posterior 95% credible interval on the difference in mortality identified a future randomized controlled trial would be extremely unlikely to find a mortality benefit for high-flow nasal cannula oxygen over bubble continuous positive airway pressure, regardless of the scenario. Interpreting these findings using the "range of practical equivalence" framework would recommend rejecting the hypothesis that high-flow nasal cannula oxygen is superior to bubble continuous positive airway pressure for these children. For children younger than 5 years with pneumonia, high-flow nasal cannula oxygen has higher mortality than bubble continuous positive airway pressure. A future randomized controlled trial in this population is unlikely to find high-flow nasal cannula oxygen superior to bubble continuous positive airway pressure.

Commercial opportunities in bioseparations and physiological testing aboard Space Station Freedom

NASA Technical Reports Server (NTRS)

Hymer, W. C.

1992-01-01

The Center for Cell Research (CCR) is a NASA Center for the Commercial Development of Space which has as its main goal encouraging industry-driven biomedical/biotechnology space projects. Space Station Freedom (SSF) will provide long duration, crew-tended microgravity environments which will enhance the opportunities for commercial biomedical/biotechnology projects in bioseparations and physiological testing. The CCR bioseparations program, known as USCEPS (for United States Commercial Electrophoresis Program in Space), is developing access for American industry to continuous-flow electrophoresis aboard SSF. In space, considerable scale-up of continuous free-flow electrophoresis is possible for cells, sub cellular particles, proteins, growth factors, and other biological products. The lack of sedemination and buoyancy-driven convection flow enhances purity of separations and the amount of material processed/time. Through the CCR's physiological testing program, commercial organizations will have access aboard SSF to physiological systems experiments (PSE's); the Penn State Biomodule; and telemicroscopy. Physiological systems experiments involve the use of live animals for pharmaceutical product testing and discovery research. The Penn State Biomodule is a computer-controlled mini lab useful for projects involving live cells or tissues and macro molecular assembly studies, including protein crystallization. Telemicroscopy will enable staff on Earth to manipulate and monitor microscopic specimens on SSF for product development and discovery research or for medical diagnosis of astronaut health problems. Space-based product processing, testing, development, and discovery research using USCEPS and CCR's physiological testing program offer new routes to improved health on Earth. Direct crew involvement-in biomedical/biotechnology projects aboard SSF will enable better experimental outcomes. The current data base shows that there is reason for considerable optimism regarding what the CCDS program and the biomedical/biotechnology industry can expect to gain from a permanent manned presence in space.

Observations from borehole dilution logging experiments in fractured crystalline rock under variable hydraulic conditions

USGS Publications Warehouse

Harte, Philip T.; Anderson, Alton; Williams, John H.

2014-01-01

Identifying hydraulically active fractures in low permeability, crystalline-bedrock aquifers requires a variety of geophysical and hydrogeophysical borehole tools and approaches. One such approach is Single Borehole Dilution Tests (SBDT), which in some low flow cases have been shown to provide greater resolution of borehole flow than other logging procedures, such as vertical differential Heat Pulse Flowmeter (HPFM) logging. Because the tools used in SBDT collect continuous profiles of water quality or dye changes, they can identify horizontal flow zones and vertical flow. We used SBDT with a food grade blue dye as a tracer and dual photometer-nephelometer measurements to identify low flow zones.SBDT were conducted at seven wells with open boreholes (exceeding 300 ft). At most of the wells HPFM logs were also collected. The seven wells are set in low-permeability, fractured granite and gneiss rocks underlying a former tetrachloroeythylene (PCE) source area at the Savage Municipal Well Superfund site in Milford, NH. Time series SBDT logs were collected at each of the seven wells under three distinct hydraulic conditions: (1) ambient conditions prior to a pump test at an adjacent well, (2) mid test, after 2-3 days of the start of the pump test, and (3) at the end of the test, after 8-9 days of the pump test. None of the SBDT were conducted under pumping conditions in the logged well. For each condition, wells were initially passively spiked with blue dye once and subsequent time series measurements were made.Measurement accuracy and precision of the photometer tool is important in SBDT when attempting to detect low rates of borehole flow. Tests indicate that under ambient conditions, none of the wells had detectable flow as measured with HPFM logging. With SBDT, 4 of the 7 showed the presence of some very low flow. None of 5 (2 of the 7 wells initially logged with HPFM under ambient conditions were not re-logged) wells logged with the HPFM during the pump test had detectable flow. However, 3 of the 5 wells showed the patterns of very low flow with SBDT during the pump test including pumping induced changes of inflow and outflow patterns at one well.

Continuous Flow Hygroscopicity-Resolved Relaxed Eddy Accumulation (Hy-Res REA) Method of Measuring Size-Resolved Sea-Salt Particle Fluxes

NASA Astrophysics Data System (ADS)

Meskhidze, N.; Royalty, T. M.; Phillips, B.; Dawson, K. W.; Petters, M. D.; Reed, R.; Weinstein, J.; Hook, D.; Wiener, R.

2017-12-01

The accurate representation of aerosols in climate models requires direct ambient measurement of the size- and composition-dependent particle production fluxes. Here we present the design, testing, and analysis of data collected through the first instrument capable of measuring hygroscopicity-based, size-resolved particle fluxes using a continuous-flow Hygroscopicity-Resolved Relaxed Eddy Accumulation (Hy-Res REA) technique. The different components of the instrument were extensively tested inside the US Environmental Protection Agency's Aerosol Test Facility for sea-salt and ammoniums sulfate particle fluxes. The new REA system design does not require particle accumulation, therefore avoids the diffusional wall losses associated with long residence times of particles inside the air collectors of the traditional REA devices. The Hy-Res REA system used in this study includes a 3-D sonic anemometer, two fast-response solenoid valves, two Condensation Particle Counters (CPCs), a Scanning Mobility Particle Sizer (SMPS), and a Hygroscopicity Tandem Differential Mobility Analyzer (HTDMA). A linear relationship was found between the sea-salt particle fluxes measured by eddy covariance and REA techniques, with comparable theoretical (0.34) and measured (0.39) proportionality constants. The sea-salt particle detection limit of the Hy-Res REA flux system is estimated to be 6x105 m-2s-1. For the conditions of ammonium sulfate and sea-salt particles of comparable source strength and location, the continuous-flow Hy-Res REA instrument was able to achieve better than 90% accuracy of measuring the sea-salt particle fluxes. In principle, the instrument can be applied to measure fluxes of particles of variable size and distinct hygroscopic properties (i.e., mineral dust, black carbon, etc.).

Addition of acetate improves stability of power generation using microbial fuel cells treating domestic wastewater.

PubMed

Stager, Jennifer L; Zhang, Xiaoyuan; Logan, Bruce E

2017-12-01

Power generation using microbial fuel cells (MFCs) must provide stable, continuous conversion of organic matter in wastewaters into electricity. However, when relatively small diameter (0.8cm) graphite fiber brush anodes were placed close to the cathodes in MFCs, power generation was unstable during treatment of low strength domestic wastewater. One reactor produced 149mW/m 2 before power generation failed, while the other reactor produced 257mW/m 2 , with both reactors exhibiting severe power overshoot in polarization tests. Using separators or activated carbon cathodes did not result in stable operation as the reactors continued to exhibit power overshoot based on polarization tests. However, adding acetate (1g/L) to the wastewater produced stable performance during fed batch and continuous flow operation, and there was no power overshoot in polarization tests. These results highlight the importance of wastewater strength and brush anode size for producing stable and continuous power in compact MFCs. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-flow characteristics of Indiana streams

USGS Publications Warehouse

Fowler, K.K.; Wilson, J.T.

1996-01-01

Knowledge of low-flow characteristics of streams is essential for management of water resources. Low-flow characteristics are presented for 229 continuous-record, streamflow-gaging stations and 285 partial-record stations in Indiana. Low- flow-frequency characteristics were computed for 210 continuous-record stations that had at least 10 years of record, and flow-duration curves were computed for all continuous-record stations. Low-flow-frequency and flow-duration analyses are based on available streamflow records through September 1993. Selected low-flow-frequency curves were computed for annual low flows and seasonal low flows. The four seasons are represented by the 3-month groups of March-May, June-August, September-November, and December- February. The 7-day, 10-year and the 7-day, 2 year low flows were estimated for 285 partial-record stations, which are ungaged sites where streamflow measurements were made at base flow. The same low-flow characteristics were estimated for 19 continuous-record stations where less than 10 years of record were available. Precipitation and geology directly influence the streams in Indiana. Streams in the northern, glaciated part of the State tend to have higher sustained base flows than those in the nonglaciated southern part. Flow at several of the continuous-record gaging stations is affected by some form of regulation or diversion. Low-flow characteristics for continuous-record stations at which flow is affected by regulation are determined using the period of record affected by regulation; natural flows prior to regulation are not used.

Performance evaluation of the active-flow personal DataRAM PM 2.5 mass monitor (Thermo Anderson pDR-1200) designed for continuous personal exposure measurements

NASA Astrophysics Data System (ADS)

Chakrabarti, Bhabesh; Fine, Philip M.; Delfino, Ralph; Sioutas, Constantinos

The need for continuous personal monitoring for exposure to particulate matter has been demonstrated by recent health studies showing effects of PM exposure on time scales of less than a few hours. Filter-based methods cannot measure this short-term variation of PM levels, which can be quite significant considering human activity patterns. The goal of this study was to evaluate the active-flow personal DataRAM for PM 2.5 (MIE pDR-1200; Thermo Electron Corp., Franklin, MA) designed as a wearable monitor to continuously measure particle exposure. The instrument precision was found to be good (2.1%) and significantly higher than the passive pDR configuration tested previously. A comparison to other proven continuous monitors resulted in good agreement at low relative humidities. Results at higher humidity followed predictable trends and provided a correction scheme that improved the accuracy of pDR readings. The pDR response to particle size also corresponded to previously observed and theoretical errors. The active flow feature of the pDR allows collection of the sampled particles on a back-up filter. The 24-h mass measured on this filter was found to compare very well with a Federal Reference Method for PM 2.5 mass.

New test for oil soluble/water dispersible gas pipeline inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stegmann, D.W.; Asperger, R.G.

1987-01-01

The wheel test provides good mixing of the condensate and water phases, the coupons are exposed to both phases. Therefore, the wheel test cannot distinguish between inhibitors that need continuous mixing of the these phases to maintain a water dispersion of the inhibitor and inhibitors that will self disperse into the water. This concept becomes important for pipelines in stratified flow where the water can settle out. In these cases with low turbulence, the inhibitor must self disperse into the water to be effective. The paper describes a test method to measure the effectiveness of an inhibitor and its abilitymore » to self disperse. The effectiveness of several inhibitors as predicted by the new test method is discussed relative to data from the wheel test and breaker tests. Field performance of these inhibitors in a gas gathering line, with liquids in stratified flow, are cities and compared with the results of the various laboratory tests.« less

Mobile propeller dynamometer validation

NASA Astrophysics Data System (ADS)

Morris, Mason Wade

With growing interest in UAVs and OSU's interest in propeller performance and manufacturing, evaluating UAV propeller and propulsion system performance has become essential. In attempts to evaluate these propellers a mobile propeller dynamometer has been designed, built, and tested. The mobile dyno has been designed to be cost effective through the ability to load it into the back of a test vehicle to create simulated forward flight characteristics. This allows much larger propellers to be dynamically tested without the use of large and expensive wind tunnels. While evaluating the accuracy of the dyno, several improvements had to be made to get accurate results. The decisions made to design and improve the mobile propeller dyno will be discussed along with attempts to validate the dyno by comparing its results against known sources. Another large part of assuring the accuracy of the mobile dyno is determining if the test vehicle will influence the flow going into the propellers being tested. The flow into the propeller needs to be as smooth and uniform as possible. This is determined by characterizing the boundary layer and accelerated flow over the vehicle. This evaluation was accomplished with extensive vehicle aerodynamic measurements with the use of full-scale tests using a pitot-rake and the actual test vehicle. Additional tests were conducted in Oklahoma State University's low speed wind tunnel with a 1/8-scale model using qualitative flow visualization with smoke. Continuing research on the mobile dyno will be discussed, along with other potential uses for the dyno.

Future Prospects for the Total Artificial Heart.

PubMed

Sunagawa, Gengo; Horvath, David J; Karimov, Jamshid H; Moazami, Nader; Fukamachi, Kiyotaka

2016-01-01

A total artificial heart (TAH) is the sole remaining option for patients with biventricular failure who cannot be rescued by left ventricular assist devices (LVADs) alone. However, the pulsatile TAH in clinical use today has limitations: large pump size, unknown durability, required complex anticoagulation regimen, and association with significant postsurgical complications. That pump is noisy; its large pneumatic driving lines traverse the body, with bulky external components for its drivers. Continuous-flow pumps, which caused a paradigm shift in the LVAD field, have already contributed to the rapidly evolving development of TAHs. Novel continuous-flow TAHs are only in preclinical testing or developmental stages. We here review the current state of TAHs, with recommended requirements for the TAH of the future.

Comparison of the release of constituents from granular materials under batch and column testing.

PubMed

Lopez Meza, Sarynna; Garrabrants, Andrew C; van der Sloot, Hans; Kosson, David S

2008-01-01

Column leaching testing can be considered a better basis for assessing field impact data than any other available batch test method and thus provides a fundamental basis from which to estimate constituent release under a variety of field conditions. However, column testing is time-intensive compared to the more simplified batch testing, and may not always be a viable option when making decisions for material reuse. Batch tests are used most frequently as a simple tool for compliance or quality control reasons. Therefore, it is important to compare the release that occurs under batch and column testing, and establish conservative interpretation protocols for extrapolation from batch data when column data are not available. Five different materials (concrete, construction debris, aluminum recycling residue, coal fly ash and bottom ash) were evaluated via batch and column testing, including different column flow regimes (continuously saturated and intermittent unsaturated flow). Constituent release data from batch and column tests were compared. Results showed no significant difference between the column flow regimes when constituent release data from batch and column tests were compared. In most cases batch and column testing agreed when presented in the form of cumulative release. For arsenic in carbonated materials, however, batch testing underestimates the column constituent release for most LS ratios and also on a cumulative basis. For cases when As is a constituent of concern, column testing may be required.

Continuous flow, explosives vapor generator and sensor chamber.

PubMed

Collins, Greg E; Giordano, Braden C; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D; Tucker, John E; Malito, Michael; Eversole, Jay D; Rose-Pehrsson, Susan

2014-05-01

A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

Visualisation of the flow at the tip of a high speed axial flow turbine rotor: An assessment of flow visualisation techniques and the requirement of the experimental turbine

NASA Astrophysics Data System (ADS)

Bindon, J.; Alder, D.; Ianovici, I.

1987-11-01

The field of flow visualization has been reviewed and its application to the study of the flow near the tip of an unshrouded axial turbine rotor discussed in detail. The logical conceptualization of experiments which could lead to a final understanding of the flow structure was developed and how this leads to test turbine design philosophy is suggested. The rotor periodicity shed by the stator requires that particle of pulse tracing is needed rather than the more universal continuous streamline trace which arises from a continuous tracer injection at a point in a flow. While the whole field of flow visualization at a rotor tip is demanding because of its very nature, pulse tracking will place a greater demand on the development of new skills and techniques. Since streamline tracking is somewhat more standard, these demands will not be as great. A fundamental choice does however need to be made between the two methods. The suggested experimental turbine should thus, always with the facility of infinitely variable Mach number, model the following: (1) Stationary annular cascade with tip clearance inside a stationary outer endwall; (2) Stationary annular cascade with tip clearance inside a moving endwall; (3) The transfer of flow visualization techniques developed into the rotating frame; (4) Fully rotating rotor with no inlet periodicity; (5) Fully rotating rotor with inlet periodicity.

Functional Changes of Diaphragm Type Shunt Valves Induced by Pressure Pulsation

NASA Astrophysics Data System (ADS)

Lee, Chong-Sun; Suh, Chang-Min; Ra, Young-Shin

Shunt valves used to treat patients with hydrocephalus were tested to investigate influence of pressure pulsation on their flow control characteristics. Our focus was on flow dynamic and functional changes of the small and thin diaphragms in the valves that serve as the main flow control mechanism and are made from silicone elastomer. Firstly, pressure-flow control curves were compared under pulsed and steady flow (without pulsation) conditions. Secondly, functional changes of the valves were tested after a long-term continuous pulsation with a peristaltic pump. Thirdly, flushing procedures selectively conducted by neurosurgeons were simulated with a fingertip pressed on the dome of the valves. As 20cc/hr of flow rate was adjusted at a constant pressure, application of 40mmH2O of pressure pulse increased flow rate through shunt valves more than 60%. As a 90cm length silicone catheter was connected to the valve outlet, increase in the flow rate was substantially reduced to 17.5%. Pressure-flow control characteristics of some valves showed significant changes after twenty-eight days of pressure pulsation at 1.0 Hz under 50.0cc/hr of flow rate. Flushing simulation resulted in temporary decrease in the pressure level. It took three hours to fully recover the normal pressure-flow control characteristics after the flushing. Our results suggest that shunt valves with a thin elastic diaphragm as the main flow control mechanism are sensitive to intracranial pressure pulsation or pressure spikes enough to change their pressure-flow control characteristics.

The assembly and use of continuous flow systems for chemical synthesis.

PubMed

Britton, Joshua; Jamison, Timothy F

2017-11-01

The adoption of and opportunities in continuous flow synthesis ('flow chemistry') have increased significantly over the past several years. Continuous flow systems provide improved reaction safety and accelerated reaction kinetics, and have synthesised several active pharmaceutical ingredients in automated reconfigurable systems. Although continuous flow platforms are commercially available, systems constructed 'in-lab' provide researchers with a flexible, versatile, and cost-effective alternative. Herein, we describe the assembly and use of a modular continuous flow apparatus from readily available and affordable parts in as little as 30 min. Once assembled, the synthesis of a sulfonamide by reacting 4-chlorobenzenesulfonyl chloride with dibenzylamine in a single reactor coil with an in-line quench is presented. This example reaction offers the opportunity to learn several important skills including reactor construction, charging of a back-pressure regulator, assembly of stainless-steel syringes, assembly of a continuous flow system with multiple junctions, and yield determination. From our extensive experience of single-step and multistep continuous flow synthesis, we also describe solutions to commonly encountered technical problems such as precipitation of solids ('clogging') and reactor failure. Following this protocol, a nonspecialist can assemble a continuous flow system from reactor coils, syringes, pumps, in-line liquid-liquid separators, drying columns, back-pressure regulators, static mixers, and packed-bed reactors.

Coal-fluid properties with an emphasis on dense phase. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klinzing, G.E.

1985-04-01

Many fossil fuel energy processes depend on the movement of solids by pneumatic transport. Despite the considerable amount of work reported in the literature on pneumatic transport, the design of new industrial systems for new products continues to rely to a great extent on empiricism. A pilot-scale test facility has been constructed at Pittsburgh Energy Technology Center (PETC), equipped with modern sophisticated measuring techniques (such as Pressure Transducers, Auburn Monitors and Micro Motion Mass Flow Meters) and an automatic computer-controlled data acquisition system to study the effects of particle pneumatic transport. Pittsburgh Seam and Montana Rosebud coals of varying sizemore » consist and moisture content were tested in the atmospheric and pressurized coal flow test loops (AP/CFTL and HP/CFTL) at PETC. The system parameters included conveying gas velocity, injector tank pressure, screw conveyor speed, pipe radius and pipe bends. In this report, results from the coal flow tests were presented and analyzed. Existing theories and correlations on two phase flows were reviewed. Experimental data were compared with values calculated from empirically or theoretically derived equations available in the literature and new correlations were proposed, when applicable, to give a better interpretation of the data and a better understanding of the various flow regimes involved in pneumatic transport. 55 refs., 56 figs., 6 tabs.« less

The 400W at 1.8K Test Facility at CEA-Grenoble

NASA Astrophysics Data System (ADS)

Roussel, P.; Girard, A.; Jager, B.; Rousset, B.; Bonnay, P.; Millet, F.; Gully, P.

2006-04-01

A new test facility with a cooling capacity respectively of 400W at 1.8K or 800W at 4.5K, is now under nominal operation in SBT (Low Temperature Department) at CEA Grenoble. It has been recently used for thermohydraulic studies of two phase superfluid helium in autumn 2004. In the near future, this test bench will allow: - to test industrial components at 1.8K (magnets, cavities of accelerators) - to continue the present studies on thermohydraulics of two phase superfluid helium - to develop and simulate new cooling loops for ITER Cryogenics, and other applications such as high Reynolds number flows This new facility consists of a cold box connected to a warm compressor station (one subatmospheric oil ring pump in series with two screw compressors). The cold box, designed by AIR LIQUIDE, comprises two centrifugal cold compressors, a cold turbine, a wet piston expander, counter flow heat exchangers and two phase separators at 4.5K and 1.8K. The new facility uses a Programmable Logic Controller (PLC) connected to a bus for the measurements. The design is modular and will allow the use of saturated fluid flow (two phase flow at 1.8K or 4.5K) or single phase fluid forced flow. Experimental results and cooling capacity in different operation modes are detailed.

Uniform, stable supply of medium for in vitro cell culture using a robust chamber

NASA Astrophysics Data System (ADS)

Wei, Juan; Liu, Chong; Jiang, Yang; Liu, Tao; Chen, Li; Liu, Bo; Li, Jingmin

2018-06-01

A uniform, stable supply of medium is important for in vitro cell culture. In this paper, a microfluidic device is presented for culturing cells inside a robust chamber with continuous perfusion of medium. The device consists of a main channel, two bifurcated channels and a culture chamber. The culture chamber connects to the bifurcated channels via multiple paths, and distributes symmetrically on the main channel, to improve the efficiency of medium exchange. Furthermore, regular polygonal chambers with various numbers of edges have been designed, to study the effects of chamber shape on flow fields. The finite element method has been employed to predict the effects of multiple paths on the uniformity and stability of flow fields in the culture chamber. Particle tracking technology has been used to evaluate the flow fields in the chambers, and PC-12 cells have been cultured using the microfluidic device, to test its validity. The results of simulation and experiment indicate that the microfluidic design could provide a continuous interstitial-like flow microenvironment, with a relatively stable and uniform supply of medium.

Brief Communication: A low-cost Arduino®-based wire extensometer for earth flow monitoring

NASA Astrophysics Data System (ADS)

Guerriero, Luigi; Guerriero, Giovanni; Grelle, Gerardo; Guadagno, Francesco M.; Revellino, Paola

2017-06-01

Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift.

Effect of Riblets on Pressure Recovery in a Straight-Walled Diffuser

DTIC Science & Technology

1990-12-01

in the boundary layer velocity pro - file. As the flow continues to oppose the adverse pressure gradient, the fluid near the wall begins to flow in the...and was 37 inches long. The floor and ceiling of the test section were con - 3 structed of wood and the side panels were made of plexiglass. Both side...the diffuser remained fairly con - stant at 52 percent. The riblet results seem to follow the same trend, providing an approximate 35 percent increase in

Classical and generalized Horton laws for peak flows in rainfall-runoff events.

PubMed

Gupta, Vijay K; Ayalew, Tibebu B; Mantilla, Ricardo; Krajewski, Witold F

2015-07-01

The discovery of the Horton laws for hydrologic variables has greatly lagged behind geomorphology, which began with Robert Horton in 1945. We define the classical and the generalized Horton laws for peak flows in rainfall-runoff events, which link self-similarity in network geomorphology with river basin hydrology. Both the Horton laws are tested in the Iowa River basin in eastern Iowa that drains an area of approximately 32 400 km(2) before it joins the Mississippi River. The US Geological Survey continuously monitors the basin through 34 stream gauging stations. We select 51 rainfall-runoff events for carrying out the tests. Our findings support the existence of the classical and the generalized Horton laws for peak flows, which may be considered as a new hydrologic discovery. Three different methods are illustrated for estimating the Horton peak-flow ratio due to small sample size issues in peak flow data. We illustrate an application of the Horton laws for diagnosing parameterizations in a physical rainfall-runoff model. The ideas and developments presented here offer exciting new directions for hydrologic research and education.

Errors in fluid balance with pump control of continuous hemodialysis.

PubMed

Roberts, M; Winney, R J

1992-02-01

The use of pumps both proximal and distal to the dialyzer during continuous hemodialysis provides control of dialysate and ultrafiltration flow rates, thereby reducing nursing time. However, we had noted unexpected severe extracellular fluid depletion suggesting that errors in pump delivery may be responsible. We measured in vitro the operation of various pumps under conditions similar to continuous hemodialysis. Fluid delivery of peristaltic and roller pumps varied with how the tubing set was inserted in the pump. Piston and peristaltic pumps with dedicated pump segments were more accurate. Pumps should be calibrated and tested under conditions simulating continuous hemodialysis prior to in vivo use.

Low-pressure sequential compression of lower limbs enhances forearm skin blood flow.

PubMed

Amah, Guy; Voicu, Sebastian; Bonnin, Philippe; Kubis, Nathalie

2016-12-01

We investigated whether forearm skin blood flow could be improved when a multilayer pulsatile inflatable suit was applied at a low pressure to the lower limbs and abdomen. We hypothesized that a non-invasive purely mechanical stimulation of the lower limbs could induce remote forearm blood flow modifications. The pulsatile suit induced a sequential compartmentalized low compression (65 mmHg), which was synchronized with each diastole of the cardiac cycle with each phase evolving centripetally (lower limbs to abdomen). Modifications of the forearm skin blood flow were continuously recorded by laser Doppler flowmetry (LDF) at baseline and during the pulsatile suit application. Endothelium-dependent and endothelium-independent vasodilations of the forearm skin microcirculation were measured by LDF in response to a local transdermal iontophoretic application of acetylcholine (ACh-test) and to hyperthermia (hyperT- test). Twenty-four healthy volunteers, 12 men and 12 women (43±14 years) were included in the study. LDF responses increased 1) under pulsatile suit (97±106%, p.

Low-Speed Aerodynamic Data for an 0.18-Scale Model of an F-16XL with Various Leading-Edge Modifications

NASA Technical Reports Server (NTRS)

Hahne, Daniel E.

1999-01-01

Using the F-16XL as a test-bed, two strategies for improving the low-speed flying characteristics that had minimal impact on high-speed performance were evaluated. In addition to the basic F-16XL configuration several modifications to the baseline configuration were tested in the Langley 30- X 60-Foot Tunnel: 1) the notched area at the wing leading edge and fuselage juncture was removed resulting in a continuous 70 deg leading-edge sweep on the inboard portion of the wing; 2) an integral attached-flow leading-edge flap concept was added to the continuous leading edge; and 3) a deployable vortex flap concept was added to the continuous leading edge. The purpose of this report is simply to document the test configurations, test conditions, and data obtained in this investigation for future reference and analysis. No analysis is presented herein and the data only appear in tabulated format.

Alpha-environmental continuous air monitor inlet

DOEpatents

Rodgers, John C.

2003-01-01

A wind deceleration and protective shroud that provides representative samples of ambient aerosols to an environmental continuous air monitor (ECAM) has a cylindrical enclosure mounted to an input on the continuous air monitor, the cylindrical enclosure having shrouded nozzles located radially about its periphery. Ambient air flows, often along with rainwater flows into the nozzles in a sampling flow generated by a pump in the continuous air monitor. The sampling flow of air creates a cyclonic flow in the enclosure that flows up through the cylindrical enclosure until the flow of air reaches the top of the cylindrical enclosure and then is directed downward to the continuous air monitor. A sloped platform located inside the cylindrical enclosure supports the nozzles and causes any moisture entering through the nozzle to drain out through the nozzles.

Continuation Power Flow with Variable-Step Variable-Order Nonlinear Predictor

NASA Astrophysics Data System (ADS)

Kojima, Takayuki; Mori, Hiroyuki

This paper proposes a new continuation power flow calculation method for drawing a P-V curve in power systems. The continuation power flow calculation successively evaluates power flow solutions through changing a specified value of the power flow calculation. In recent years, power system operators are quite concerned with voltage instability due to the appearance of deregulated and competitive power markets. The continuation power flow calculation plays an important role to understand the load characteristics in a sense of static voltage instability. In this paper, a new continuation power flow with a variable-step variable-order (VSVO) nonlinear predictor is proposed. The proposed method evaluates optimal predicted points confirming with the feature of P-V curves. The proposed method is successfully applied to IEEE 118-bus and IEEE 300-bus systems.

Results of test 0A82 in the NASA/LRC 31 inch CFHT on an 0.010-scale model (32-0) of the space shuttle configuration 3 to determine RCS jet flow field interaction and to investigate RT real gas effects

NASA Technical Reports Server (NTRS)

Thornton, D. E.

1975-01-01

Tests were conducted in the NASA Langley Research Center 31-inch Continuous Flow Hypersonic Wind Tunnel to determine RCS jet interaction effects on hypersonic aerodynamic characteristics and to investigate RT (gas constant times temperature) scaling effects on the RCS similitude. The model was an 0.010-scale replica of the Space Shuttle Orbiter Configuration 3. Hypersonic aerodynamic data were obtained from tests at Mach 10.3 and dynamic pressures of 200, 150, 125, and 100 psf. The RCS modes of pitch, yaw, and roll at free flight dynamic pressure simulation of 20 psf were investigated.

High velocity continuous-flow reactor for the production of solar grade silicon

NASA Technical Reports Server (NTRS)

Woerner, L.

1977-01-01

The feasibility of a high volume, high velocity continuous reduction reactor as an economical means of producing solar grade silicon was tested. Bromosilanes and hydrogen were used as the feedstocks for the reactor along with preheated silicon particles which function both as nucleation and deposition sites. A complete reactor system was designed and fabricated. Initial preheating studies have shown the stability of tetrabromosilane to being heated as well as the ability to preheat hydrogen to the desired temperature range. Several test runs were made and some silicon was obtained from runs carried out at temperatures in excess of 1180 K.

State of the art of aerobic granulation in continuous flow bioreactors.

PubMed

Kent, Timothy R; Bott, Charles B; Wang, Zhi-Wu

In the wake of the success of aerobic granulation in sequential batch reactors (SBRs) for treating wastewater, attention is beginning to turn to continuous flow applications. This is a necessary step given the advantages of continuous flow treatment processes and the fact that the majority of full-scale wastewater treatment plants across the world are operated with aeration tanks and clarifiers in a continuous flow mode. As in SBRs, applying a selection pressure, based on differences in either settling velocity or the size of the biomass, is essential for successful granulation in continuous flow reactors (CFRs). CFRs employed for aerobic granulation come in multiple configurations, each with their own means of achieving such a selection pressure. Other factors, such as bioaugmentation and hydraulic shear force, also contribute to aerobic granulation to some extent. Besides the formation of aerobic granules, long-term stability of aerobic granules is also a critical issue to be addressed. Inorganic precipitation, special inocula, and various operational optimization strategies have been used to improve granule long-term structural integrity. Accumulated studies reviewed in this work demonstrate that aerobic granulation in CFRs is capable of removing a wide spectrum of contaminants and achieving properties generally comparable to those in SBRs. Despite the notable research progress made toward successful aerobic granulation in lab-scale CFRs, to the best of our knowledge, there are only three full-scale tests of the technique, two being seeded with anammox-supported aerobic granules and the other with conventional aerobic granules; two other process alternatives are currently in development. Application of settling- or size-based selection pressures and feast/famine conditions are especially difficult to implement to these and similar mainstream systems. Future research efforts needs to be focused on the optimization of the granule-to-floc ratio, enhancement of granule activity, improvement of long-term granule stability, and a better understanding of aerobic granulation mechanisms in CFRs, especially in full-scale applications. Copyright © 2018 Elsevier Inc. All rights reserved.

Analysis of blood flow in the long posterior ciliary artery of the cat.

PubMed

Koss, M C

1999-03-01

Experiments were undertaken to use a new technique for direct on-line measurement of blood flow in the long posterior ciliary artery (LPCA) in cats and to evaluate possible physiological mechanisms controlling blood flow in the vascular beds perfused by this artery. Blood flow in the temporal LPCA was measured on a continuous basis using ultrasonic flowmetry in anesthetized cats. Effects of acute sectioning of the sympathetic nerve and changes in LPCA and cerebral blood flows in response to altered levels of inspired CO2 and O2 were tested in some animals. In others, the presence of vascular autoregulatory mechanisms in response to stepwise elevations of intraocular pressure was studied. Blood flow in the temporal LPCA averaged 0.58+/-0.03 ml/min in 45 cats anesthetized with pentobarbital. Basal LPCA blood flow was not altered by acute sectioning of the sympathetic nerve or by changes in low levels of inspired CO2 and O2, although 10% CO2 caused a modest increase. Stepwise elevations of intraocular pressure resulted in comparable stepwise decreases of LPCA blood flow, with perfusion pressure declining in a linear manner throughout the perfusion-pressure range. Ultrasonic flowmetry seems to be a useful tool for continuous on-line measurement of LPCA blood flow in the cat eye. Blood flow to vascular beds perfused by this artery does not seem to be under sympathetic neural control and is refractory to modest alterations of blood gas levels of CO2 and O2. Blood vessels perfused by the LPCA show no clear autoregulatory mechanisms.

Testing seismic amplitude source location for fast debris-flow detection at Illgraben, Switzerland

NASA Astrophysics Data System (ADS)

Walter, Fabian; Burtin, Arnaud; McArdell, Brian W.; Hovius, Niels; Weder, Bianca; Turowski, Jens M.

2017-06-01

Heavy precipitation can mobilize tens to hundreds of thousands of cubic meters of sediment in steep Alpine torrents in a short time. The resulting debris flows (mixtures of water, sediment and boulders) move downstream with velocities of several meters per second and have a high destruction potential. Warning protocols for affected communities rely on raising awareness about the debris-flow threat, precipitation monitoring and rapid detection methods. The latter, in particular, is a challenge because debris-flow-prone torrents have their catchments in steep and inaccessible terrain, where instrumentation is difficult to install and maintain. Here we test amplitude source location (ASL) as a processing scheme for seismic network data for early warning purposes. We use debris-flow and noise seismograms from the Illgraben catchment, Switzerland, a torrent system which produces several debris-flow events per year. Automatic in situ detection is currently based on geophones mounted on concrete check dams and radar stage sensors suspended above the channel. The ASL approach has the advantage that it uses seismometers, which can be installed at more accessible locations where a stable connection to mobile phone networks is available for data communication. Our ASL processing uses time-averaged ground vibration amplitudes to estimate the location of the debris-flow front. Applied to continuous data streams, inversion of the seismic amplitude decay throughout the network is robust and efficient, requires no manual identification of seismic phase arrivals and eliminates the need for a local seismic velocity model. We apply the ASL technique to a small debris-flow event on 19 July 2011, which was captured with a temporary seismic monitoring network. The processing rapidly detects the debris-flow event half an hour before arrival at the outlet of the torrent and several minutes before detection by the in situ alarm system. An analysis of continuous seismic records furthermore indicates that detectability of Illgraben debris flows of this size is unaffected by changing environmental and anthropogenic seismic noise and that false detections can be greatly reduced with simple processing steps.

Analysis of fine coal pneumatic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathur, M.P.; Rohatgi, N.D.; Klinzing, G.E.

1987-01-01

Many fossil fuel energy processes depend on the movement of solids by pneumatic transport. Despite the considerable amount of work reported in the literature on pneumatic transport, the design of new industrial systems for new products continues to rely to a great extent on empiricism. A pilot-scale test facility has been constructed at Pittsburgh Energy Technology Center (PETC) and is equipped with modern sophisticated measuring techniques (such as Pressure Transducers, Auburn Monitors, Micro Motion Mass flowmeters) and an automatic computer-controlled data acquisition system to study the effects of particle pneumatic transport. Pittsburgh Seam and Montana rosebud coals of varying sizemore » consist and moisture content were tested in the atmospheric and pressurized coal flow test loops (AP/CFTL and HP/CFTL) at PETC. The system parameters included conveying gas velocity, injector tank pressure, screw conveyor speed, pipe radius, and pipe bends. In the following report, results from the coal flow tests were presented and analyzed. Existing theories and correlations on two-phase flows were reviewed. Experimental data were compared with values calculated from empirically or theoretically derived equations available in the literature, and new correlations were proposed, when applicable, to give a better interpretation of the data and a better understanding of the various flow regimes involved in pneumatic transport. 55 refs., 56 figs., 6 tabs.« less

Microdevice for plasma separation from whole human blood using bio-physical and geometrical effects

PubMed Central

Tripathi, Siddhartha; Kumar, Y. V. BalaVarun; Agrawal, Amit; Prabhakar, Amit; Joshi, Suhas S.

2016-01-01

In this research work, we present a simple and efficient passive microfluidic device for plasma separation from pure blood. The microdevice has been fabricated using conventional photolithography technique on a single layer of polydimethylsiloxane, and has been extensively tested on whole blood and enhanced (upto 62%) hematocrit levels of human blood. The microdevice employs elevated dimensions of about 100 μm; such elevated dimensions ensure clog-free operation of the microdevice and is relatively easy to fabricate. We show that our microdevice achieves almost 100% separation efficiency on undiluted blood in the flow rate range of 0.3 to 0.5 ml/min. Detailed biological characterization of the plasma obtained from the microdevice is carried out by testing: proteins by ultra-violet spectrophotometric method, hCG (human chorionic gonadotropin) hormone, and conducting random blood glucose test. Additionally, flow cytometry study has also been carried on the separated plasma. These tests attest to the high quality of plasma recovered. The microdevice developed in this work is an outcome of extensive experimental research on understanding the flow behavior and separation phenomenon of blood in microchannels. The microdevice is compact, economical and effective, and is particularly suited in continuous flow operations. PMID:27279146

Heated, humidified high-flow nasal cannula therapy: yet another way to deliver continuous positive airway pressure?

PubMed

Kubicka, Zuzanna J; Limauro, Joseph; Darnall, Robert A

2008-01-01

The goal was to estimate the level of delivered continuous positive airway pressure by measuring oral cavity pressure with the mouth closed in infants of various weights and ages treated with heated, humidified high-flow nasal cannula at flow rates of 1-5 L/minute. We hypothesized that clinically relevant levels of continuous positive airway pressure would not be achieved if a nasal leak is maintained. After performing bench measurements and demonstrating that oral cavity pressure closely approximated levels of traditionally applied nasal continuous positive airway pressure, we successfully measured oral cavity pressure during heated, humidified, high-flow nasal cannula treatment in 27 infants. Small (outer diameter: 0.2 cm) cannulae were used for all infants, and flow rates were left as ordered by providers. Bench measurements showed that, for any given leak size, there was a nearly linear relationship between flow rate and pressure. The highest pressure achieved was 4.5 cmH2O (flow rate: 8 L/minute; leak: 3 mm). In our study infants (postmenstrual age: 29.1-44.7 weeks; weight: 835-3735 g; flow rate: 1-5 L/minute), no pressure was generated with the mouth open at any flow rate. With the mouth closed, the oral cavity pressure was related to both flow rate and weight. For infants of < or = 1500 g, there was a linear relationship between flow rate and oral cavity pressure. Oral cavity pressure can estimate the level of continuous positive airway pressure. Continuous positive airway pressure generated with heated, humidified, high-flow nasal cannula treatment depends on the flow rate and weight. Only in the smallest infants with the highest flow rates, with the mouth fully closed, can clinically significant but unpredictable levels of continuous positive airway pressure be achieved. We conclude that heated, humidified high-flow nasal cannula should not be used as a replacement for delivering continuous positive airway pressure.

High-resolution continuous-flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

NASA Astrophysics Data System (ADS)

Emanuelsson, B. D.; Baisden, W. T.; Bertler, N. A. N.; Keller, E. D.; Gkinis, V.

2015-07-01

Here we present an experimental setup for water stable isotope (δ18O and δD) continuous-flow measurements and provide metrics defining the performance of the setup during a major ice core measurement campaign (Roosevelt Island Climate Evolution; RICE). We also use the metrics to compare alternate systems. Our setup is the first continuous-flow laser spectroscopy system that is using off-axis integrated cavity output spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research, LGR) in combination with an evaporation unit to continuously analyze water samples from an ice core. A Water Vapor Isotope Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to (1) enable measurements on several water standards, (2) increase the temporal resolution by reducing the response time and (3) reduce the influence from memory effects. While this setup was designed for the continuous-flow analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. The custom setups provide a shorter response time (~ 54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~ 62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the custom setups have a reduced memory effect. Stability tests comparing the custom and WVISS setups were performed and Allan deviations (σAllan) were calculated to determine precision at different averaging times. For the custom 2013 setup the precision after integration times of 103 s is 0.060 and 0.070 ‰ for δ18O and δD, respectively. The corresponding σAllan values for the custom 2014 setup are 0.030, 0.060 and 0.043 ‰ for δ18O, δD and δ17O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042 ‰ after 103 s for δ18O, δD and δ17O, respectively. Both the custom setups and WVISS setup are influenced by instrumental drift with δ18O being more drift sensitive than δD. The σAllan values for δ18O are 0.30 and 0.18 ‰ for the custom 2013 and WVISS setup, respectively, after averaging times of 104 s (2.78 h). Using response time tests and stability tests, we show that the custom setups are more responsive (shorter response time), whereas the University of Copenhagen (UC) setup is more stable. More broadly, comparisons of different setups address the challenge of integrating vaporizer/spectrometer isotope measurement systems into a CFA campaign with many other analytical instruments.

High Temperature Tribometer. Phase 1

DTIC Science & Technology

1989-06-01

13 Figure 2.3.2 Setpoint and Gain Windows in FW.EXE ......... . Figure 2.4.1 Data-Flow Diagram for Data-Acquisition Module ..... .. 23 I Figure...mounted in a friction force measuring device. Optimally , material testing results should not be test machine sensitiye; but due to equipment variables...fixed. The friction force due to sliding should be continuously measured. This is optimally done in conjunction with the normal force measurement via

21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continuous flow sequential multiple chemistry..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2150 Continuous flow sequential multiple chemistry...

An efficient and more sustainable one-step continuous-flow multicomponent synthesis approach to chromene derivatives

EPA Science Inventory

A simple and rapid one-step continuous-flow synthesis route has been developed for the preparation of chromene derivatives from the reaction of aromatic aldehydes, α-cyanomethylene compounds and naphthols. In this contribution, a one-step continuous-flow protocol in a continuous ...

21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Continuous flow sequential multiple chemistry..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2150 Continuous flow sequential multiple chemistry...

21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Continuous flow sequential multiple chemistry..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2150 Continuous flow sequential multiple chemistry...

21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Continuous flow sequential multiple chemistry..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2150 Continuous flow sequential multiple chemistry...

21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Continuous flow sequential multiple chemistry..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2150 Continuous flow sequential multiple chemistry...

Flow-induced vibration and fretting-wear damage in a moisture separator reheater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pettigrew, M.J.; Taylor, C.E.; Fisher, N.J.

1996-12-01

Tube failures due to excessive flow-induced vibration were experienced in the tube bundles of moisture separator reheaters in a BWR nuclear station. This paper presents the results of a root cause analysis and covers recommendations for continued operation and for replacement tube bundles. The following tasks are discussed: tube failure analysis; flow velocity distribution calculations; flow-induced vibration analysis with particular emphasis on finned-tubes; fretting-wear testing of a tube and tube-support material combination under simulated operating conditions; field measurements of flow-induced vibration; and development of vibration specifications for replacement tube bundles. The effect of transient operating conditions and of other operationalmore » changes such as tube fouling were considered in the analysis. This paper outlines a typical field problem and illustrates the application of flow-induced vibration technology for the solution of a practical problem.« less

Burner rig study of variables involved in hole plugging of air cooled turbine engine vanes

NASA Technical Reports Server (NTRS)

Deadmore, D. L.; Lowell, C. E.

1983-01-01

The effects of combustion gas composition, flame temperatures, and cooling air mass flow on the plugging of film cooling holes by a Ca-Fe-P-containing deposit were investigated. The testing was performed on film-cooled vanes exposed to the combustion gases of an atmospheric Mach 0.3 burner rig. The extent of plugging was determined by measurement of the open hole area at the conclusion of the tests as well as continuous monitoring of some of the tests using stop-action photography. In general, as the P content increased, plugging rates also increased. The plugging was reduced by increasing flame temperature and cooling air mass flow rates. At times up to approximately 2 hours little plugging was observed. This apparent incubation period was followed by rapid plugging, reaching in several hours a maximum closure whose value depended on the conditions of the test.

Liquid Acquisition Device Testing with Sub-Cooled Liquid Oxygen

NASA Technical Reports Server (NTRS)

Jurns, John M.; McQuillen, John B.

2008-01-01

When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. Previous experimental test programs conducted at NASA have collected LAD data for a number of cryogenic fluids, including: liquid nitrogen (LN2), liquid oxygen (LOX), liquid hydrogen (LH2), and liquid methane (LCH4). The present work reports on additional testing with sub-cooled LOX as part of NASA s continuing cryogenic LAD development program. Test results extend the range of LOX fluid conditions examined, and provide insight into factors affecting predicting LAD bubble point pressures.

Structural Monitoring and Field Test for Kao Ping Hsi Cable-Stayed Bridge in Taiwan

NASA Astrophysics Data System (ADS)

Chen, Chern-Hwa

2010-05-01

This work applies system identification techniques to analyze the measured data from structural monitoring system and field test for Kao Ping Hsi cable-stayed bridge in Taiwan. The continuous wavelet transform algorithm can be used to identify the dynamic characteristics of the cable-stayed bridge under environmental vibration. The identified results with traffic flow were compared with those obtained from ambient vibration test. The excellent agreement both the identified results from different traffic conditions indicates that the traffic flow would not significantly change the natural frequencies of the cable-stayed bridge. The modal parameters identified from the field vibration test will be compared with those used in the finite element analysis. The results obtained herein will be used as the damage detection for monitoring the long-term safety of the Kao Ping Hsi cable-stayed bridge by using structural monitoring system.

Eddy Current Flow Measurements in the FFTF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nielsen, Deborah L.; Polzin, David L.; Omberg, Ronald P.

2017-02-02

The Fast Flux Test Facility (FFTF) is the most recent liquid metal reactor (LMR) to be designed, constructed, and operated by the U.S. Department of Energy (DOE). The 400-MWt sodium-cooled, fast-neutron flux reactor plant was designed for irradiation testing of nuclear reactor fuels and materials for liquid metal fast breeder reactors. Following shut down of the Clinch River Breeder Reactor Plant (CRBRP) project in 1983, FFTF continued to play a key role in providing a test bed for demonstrating performance of advanced fuel designs and demonstrating operation, maintenance, and safety of advanced liquid metal reactors. The FFTF Program provides valuablemore » information for potential follow-on reactor projects in the areas of plant system and component design, component fabrication, fuel design and performance, prototype testing, site construction, and reactor control and operations. This report provides HEDL-TC-1344, “ECFM Flow Measurements in the FFTF Using Phase-Sensitive Detectors”, March 1979.« less

Estimation of Unsaturated Zone Traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, Using a Source-Responsive Preferential-Flow Model

USGS Publications Warehouse

Ebel, Brian A.; Nimmo, John R.

2009-01-01

Traveltimes for contaminant transport by water from a point in the unsaturated zone to the saturated zone are a concern at Rainier Mesa and Shoshone Mountain in the Nevada Test Site, Nevada. Where nuclear tests were conducted in the unsaturated zone, contaminants must traverse hundreds of meters of variably saturated rock before they enter the saturated zone in the carbonate rock, where the regional groundwater system has the potential to carry them substantial distances to a location of concern. The unsaturated-zone portion of the contaminant transport path may cause a significant delay, in addition to the time required to travel within the saturated zone, and thus may be important in the overall evaluation of the potential hazard from contamination. Downward contaminant transport through the unsaturated zone occurs through various processes and pathways; this can lead to a broad distribution of contaminant traveltimes, including exceedingly slow and unexpectedly fast extremes. Though the bulk of mobile contaminant arrives between the time-scale end members, the fastest contaminant transport speed, in other words the speed determined by the combination of possible processes and pathways that would bring a measureable quantity of contaminant to the aquifer in the shortest time, carries particular regulatory significance because of its relevance in formulating the most conservative hazard-prevention scenarios. Unsaturated-zone flow is usually modeled as a diffusive process responding to gravity and pressure gradients as mediated by the unsaturated hydraulic properties of the materials traversed. The mathematical formulation of the diffuse-flow concept is known as Richards' equation, which when coupled to a solute transport equation, such as the advection-dispersion equation, provides a framework to simulate contaminant migration in the unsaturated zone. In recent decades awareness has increased that much fluid flow and contaminant transport within the unsaturated zone takes place as preferential flow, faster than would be predicted by the coupled Richards' and advection-dispersion equations with hydraulic properties estimated by traditional means. At present the hydrologic community has not achieved consensus as to whether a modification of Richards' equation, or a fundamentally different formulation, would best quantify preferential flow. Where the fastest contaminant transport speed is what needs to be estimated, there is the possibility of simplification of the evaluation process. One way of doing so is by a two-step process in which the first step is to evaluate whether significant preferential flow and solute transport is possible for the media and conditions of concern. The second step is to carry out (a) a basic Richards' and advection-dispersion equation analysis if it is concluded that preferential flow is not possible or (b) an analysis that considers only the fastest possible preferential-flow processes, if preferential flow is possible. For the preferential-flow situation, a recently published model describable as a Source-Responsive Preferential-Flow (SRPF) model is an easily applied option. This report documents the application of this two-step process to flow through the thick unsaturated zones of Rainier Mesa and Shoshone Mountain in the Nevada Test Site. Application of the SRPF model involves distinguishing between continuous and intermittent water supply to preferential flow paths. At Rainier Mesa and Shoshone Mountain this issue is complicated by the fact that contaminant travel begins at a location deep in the subsurface, where there may be perched water that may or may not act like a continuous supply, depending on such features as the connectedness of fractures and the nature of impeding layers. We have treated this situation by hypothesizing both continuous and intermittent scenarios for contaminant transport to the carbonate aquifer and reporting estimation of the fastest speed for both of th

Estimation of unsaturated zone traveltimes for Rainier Mesa and Shoshone Mountain, Nevada Test Site, Nevada, using a source-responsive preferential-flow model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brian A. Ebel; John R. Nimmo

2009-09-11

Traveltimes for contaminant transport by water from a point in the unsaturated zone to the saturated zone are a concern at Rainier Mesa and Shoshone Mountain in the Nevada Test Site, Nevada. Where nuclear tests were conducted in the unsaturated zone, contaminants must traverse hundreds of meters of variably saturated rock before they enter the saturated zone in the carbonate rock, where the regional groundwater system has the potential to carry them substantial distances to a location of concern. The unsaturated-zone portion of the contaminant transport path may cause a significant delay, in addition to the time required to travelmore » within the saturated zone, and thus may be important in the overall evaluation of the potential hazard from contamination. Downward contaminant transport through the unsaturated zone occurs through various processes and pathways; this can lead to a broad distribution of contaminant traveltimes, including exceedingly slow and unexpectedly fast extremes. Though the bulk of mobile contaminant arrives between the time-scale end members, the fastest contaminant transport speed, in other words the speed determined by the combination of possible processes and pathways that would bring a measureable quantity of contaminant to the aquifer in the shortest time, carries particular regulatory significance because of its relevance in formulating the most conservative hazard-prevention scenarios. Unsaturated-zone flow is usually modeled as a diffusive process responding to gravity and pressure gradients as mediated by the unsaturated hydraulic properties of the materials traversed. The mathematical formulation of the diffuse-flow concept is known as Richards' equation, which when coupled to a solute transport equation, such as the advection-dispersion equation, provides a framework to simulate contaminant migration in the unsaturated zone. In recent decades awareness has increased that much fluid flow and contaminant transport within the unsaturated zone takes place as preferential flow, faster than would be predicted by the coupled Richards' and advection-dispersion equations with hydraulic properties estimated by traditional means. At present the hydrologic community has not achieved consensus as to whether a modification of Richards' equation, or a fundamentally different formulation, would best quantify preferential flow. Where the fastest contaminant transport speed is what needs to be estimated, there is the possibility of simplification of the evaluation process. One way of doing so is by a two-step process in which the first step is to evaluate whether significant preferential flow and solute transport is possible for the media and conditions of concern. The second step is to carry out (a) a basic Richards' and advection-dispersion equation analysis if it is concluded that preferential flow is not possible or (b) an analysis that considers only the fastest possible preferential-flow processes, if preferential flow is possible. For the preferential-flow situation, a recently published model describable as a Source-Responsive Preferential-Flow (SRPF) model is an easily applied option. This report documents the application of this two-step process to flow through the thick unsaturated zones of Rainier Mesa and Shoshone Mountain in the Nevada Test Site. Application of the SRPF model involves distinguishing between continuous and intermittent water supply to preferential flow paths. At Rainier Mesa and Shoshone Mountain this issue is complicated by the fact that contaminant travel begins at a location deep in the subsurface, where there may be perched water that may or may not act like a continuous supply, depending on such features as the connectedness of fractures and the nature of impeding layers. We have treated this situation by hypothesizing both continuous and intermittent scenarios for contaminant transport to the carbonate aquifer and reporting estimation of the fastest speed for both of these end members.« less

40 CFR 60.424 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Ammonium Sulfate.../ton) of ammonium sulfate produced. cs = concentration of particulate matter, g/dscm (g/dscf). Qsd = volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P = production rate of ammonium sulfate, Mg/hr (ton...

USING CONTINUOUS MONITORS FOR CONDUCTING TRACER STUDIES IN WATER DISTRIBUTION SYSTEMS

EPA Science Inventory

The use of online monitors for conducting a distribution system tracer study is proving to be an essential tool to accurately understand the flow dynamics in a distribution system. In a series of field testing sponsored by U. S. Environmental Protection Agency (EPA) and Greater ...

40 CFR 60.404 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock.../ton) of phosphate rock feed. cs=concentration of particulate matter, g/dscm (g/dscf). Qsd=volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr). K=conversion...

40 CFR 60.404 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock.../ton) of phosphate rock feed. cs = concentration of particulate matter, g/dscm (g/dscf). Qsd = volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr). K...

40 CFR 60.404 - Test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock.../ton) of phosphate rock feed. cs=concentration of particulate matter, g/dscm (g/dscf). Qsd=volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr). K=conversion...

40 CFR 60.404 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock.../ton) of phosphate rock feed. cs=concentration of particulate matter, g/dscm (g/dscf). Qsd=volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr). K=conversion...

40 CFR 60.404 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock.../ton) of phosphate rock feed. cs=concentration of particulate matter, g/dscm (g/dscf). Qsd=volumetric flow rate of effluent gas, dscm/hr (dscf/hr). P=phosphate rock feed rate, Mg/hr (ton/hr). K=conversion...

40 CFR 86.331-79 - Hydrocarbon analyzer calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86... difference between the span-gas response and the zero-gas response. Incrementally adjust the fuel flow above...

40 CFR 86.331-79 - Hydrocarbon analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86... difference between the span-gas response and the zero-gas response. Incrementally adjust the fuel flow above...

Continuous flow hygroscopicity-resolved relaxed eddy accumulation (Hy-Res REA) method of measuring size-resolved sodium chloride particle fluxes

EPA Science Inventory

The accurate representation of aerosols in climate models requires direct ambient measurement of the size- and composition-dependent particle production fluxes. Here, we present the design, testing, and analysis of data collected through the first instrument capable of measuring ...

40 CFR 86.329-79 - System response time; check procedure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86... in step (i). (2) Capillary flow analyzers. This procedure is applicable only to analyzers that have...

40 CFR 1065.202 - Data updating, recording, and control.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... 1065.202 Section 1065.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments § 1065.202 Data updating, recording... Intake-air or raw-exhaust flow rate N/A 1 Hz means. § 1065.530, § 1065.545 Dilution air if actively...

40 CFR 1065.202 - Data updating, recording, and control.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... 1065.202 Section 1065.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments § 1065.202 Data updating, recording... Intake-air or raw-exhaust flow rate N/A 1 Hz means. § 1065.530, § 1065.545 Dilution air if actively...

40 CFR 1065.202 - Data updating, recording, and control.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... 1065.202 Section 1065.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments § 1065.202 Data updating, recording... Intake-air or raw-exhaust flow rate N/A 1 Hz means. § 1065.530, § 1065.545 Dilution air if actively...

Payload Specialist Charles Walker with handheld protein growth experiment

NASA Image and Video Library

1985-11-26

61B-02-014 (26 Nov-3 Dec 1985) --- Payload Specialist Charles D. Walker works with the handheld protein growth experiment -- one of a series of tests being flown to study the possibility of crystallizing biological materials. Walker rests the experiment against the larger continuous flow electrophoresis systems experiment.

Computational fluid dynamics: Transition to design applications

NASA Technical Reports Server (NTRS)

Bradley, R. G.; Bhateley, I. C.; Howell, G. A.

1987-01-01

The development of aerospace vehicles, over the years, was an evolutionary process in which engineering progress in the aerospace community was based, generally, on prior experience and data bases obtained through wind tunnel and flight testing. Advances in the fundamental understanding of flow physics, wind tunnel and flight test capability, and mathematical insights into the governing flow equations were translated into improved air vehicle design. The modern day field of Computational Fluid Dynamics (CFD) is a continuation of the growth in analytical capability and the digital mathematics needed to solve the more rigorous form of the flow equations. Some of the technical and managerial challenges that result from rapidly developing CFD capabilites, some of the steps being taken by the Fort Worth Division of General Dynamics to meet these challenges, and some of the specific areas of application for high performance air vehicles are presented.

Reference NO2 calibration system for ground-based intercomparisons during NASA's GTE/CITE 2 mission

NASA Technical Reports Server (NTRS)

Fried, Alan; Nunnermacker, Linda; Cadoff, Barry; Sams, Robert; Yates, Nathan

1990-01-01

An NO2 calibration system, based on a permeation device and a two-stage dynamic dilution system, was designed, constructed, and characterized at the National Bureau of Standards. In this system, calibrant flow entering the second stage was controlled without contacting a metal flow controller, and permeation oven temperature and flow were continuously maintained, even during transport. The system performance and the permeation emission rate were characterized by extensive laboratory tests. This system was capable of accurately delivering known NO2 concentrations in the ppbv and sub-ppbv concentration range with a total uncertainty of approximately 10 percent. The calibration system was placed on board NASA research aircraft at both the Wallops Island and Ames research facilities. There it was employed as the reference standard in NASA's Global Tropospheric Experiment/Chemical Instrumental Test and Evaluation 2 mission in August 1986.

78 FR 65306 - Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams AGENCY: Environmental... Monitoring of Temperature and Flow in Wadeable Streams'' (EPA/600/R-13/170). The EPA also is announcing that... Development. The report describes best practices for the deployment of continuous temperature and flow sensors...

Statistics of Macroturbulence from Flow Equations

NASA Astrophysics Data System (ADS)

Marston, Brad; Iadecola, Thomas; Qi, Wanming

2012-02-01

Probability distribution functions of stochastically-driven and frictionally-damped fluids are governed by a linear framework that resembles quantum many-body theory. Besides the Fokker-Planck approach, there is a closely related Hopf functional methodfootnotetextOokie Ma and J. B. Marston, J. Stat. Phys. Th. Exp. P10007 (2005).; in both formalisms, zero modes of linear operators describe the stationary non-equilibrium statistics. To access the statistics, we generalize the flow equation approachfootnotetextF. Wegner, Ann. Phys. 3, 77 (1994). (also known as the method of continuous unitary transformationsfootnotetextS. D. Glazek and K. G. Wilson, Phys. Rev. D 48, 5863 (1993); Phys. Rev. D 49, 4214 (1994).) to find the zero mode. We test the approach using a prototypical model of geophysical and astrophysical flows on a rotating sphere that spontaneously organizes into a coherent jet. Good agreement is found with low-order equal-time statistics accumulated by direct numerical simulation, the traditional method. Different choices for the generators of the continuous transformations, and for closure approximations of the operator algebra, are discussed.

Experimental study on the disinfection efficiencies of a continuous-flow ultrasound/ultraviolet baffled reactor.

PubMed

Zhou, Xiaoqin; Guo, Hao; Li, Zifu; Zhao, Junyuan; Yun, Yupan

2015-11-01

A self-designed continuous-flow ultrasound/ultraviolet (US/UV) baffled reactor was tested in this work, and the disinfection efficiency of secondary effluent from a wastewater treatment plant (WWTP) was investigated in terms of the different locations of ultrasonic transducers inside the reactor under similar input power densities and specific energy consumptions. Results demonstrated that the two-stage simultaneous US/UV irradiation in both chambers 2 and 3 at a flow rate of 1200 L/h performed excellent disinfection efficiency. It achieved an average feacal coliforms concentration of 201±78 colony forming unit (CFU)/L in the effluent and an average of (4.24±0.26) log10 reduction. Thereafter, 8 days of continuous operation was performed under such a condition. A total of 31 samples were taken, and all the samples were analyzed in triplicate for feacal coliforms analysis. Experimental results showed that feacal coliforms concentrations remained at about 347±174 CFU/L under the selected optimum disinfection condition, even if the influent concentrations fluctuated from 3.97×10(5) to 3.57×10(6) CFU/L. This finding implied that all effluents of continuous-flow-baffled-reactor with simultaneous US/UV disinfection could meet the requirements of the discharge standard of pollutants for municipal WWTP (GB 18918-2002) Class 1-A (1000 CFU/L) with a specific energy consumption of 0.219 kWh/m(3). Therefore, the US/UV disinfection process has great potential for practical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Continuous Flow Liquid Microjunction Surface Sampling Probe Connected On-line with HPLC/MS for Spatially Resolved Analysis of Small Molecules and Proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J; Kertesz, Vilmos

RATIONALE: A continuous flow liquid microjunction surface sampling probe extracts soluble material from surfaces for direct ionization and detection by MS. Demonstrated here is the on-line coupling of such a probe with HPLC/MS enabling extraction, separation and detection of small molecules and proteins from surfaces in a spatially resolved (~0.5 mm diameter spots) manner. Methods: A continuous flow liquid microjunction surface sampling probe was connected to a 6-port, 2-position valve for extract collection and injection to an HPLC column. A QTRAP 5500 hybrid triple quadrupole linear ion trap equipped with a Turbo V ion source operated in positive ESI modemore » was used for all experiments. System operation was tested with extraction, separation and detection of propranolol and associated metabolites from drug dosed tissues and proteins from dried sheep blood spots on paper. Results: Confirmed in the tissue were the parent drug and two different hydroxypropranolol glucuronides. The mass spectrometric response for these compounds from different locations in the liver showed an increase with increasing extraction time (5, 20 and 40 s extractions). For on-line separation and detection/identification of extracted proteins from dried sheep blood spots, two major protein peaks dominated the chromatogram and could be correlated with the expected masses for the hemoglobin and chains. Conclusions: Spatially resolved sampling, separation, and detection of small molecules and proteins from surfaces can be accomplished using a continuous flow liquid microjunction surface sampling probe coupled on-line with HPLC/MS detection.« less

Effect of continuous vs pulsed iontophoresis of treprostinil on skin blood flow.

PubMed

Kotzki, Sylvain; Roustit, Matthieu; Arnaud, Claire; Godin-Ribuot, Diane; Cracowski, Jean-Luc

2015-05-25

Systemic sclerosis (SSc) is a rare disease affecting digital microcirculation, leading to finger ulcers and in some cases to amputation. Prostacyclin analogues can be used intravenously but their therapeutic effect is counterbalanced by potentially serious vasodilatation-induced side effects. Iontophoresis of treprostinil could be a promising local therapeutic alternative for SSc-related digital ulcers. Iontophoretic drug delivery is complex, and whether continuous or periodic current should be used remains debated. The objective of the present work is to compare the effect of continuous vs pulsed iontophoresis of treprostinil in rats. Treprostinil (0.64 mM and 0.064 mM) and NaCl were delivered by cathodal iontophoresis onto the hindquarters of anaesthetized rats. Three protocols delivering the same quantity of current were compared: one was continuous (100 μA during 20 min) and two were periodic (B: twenty 1-min cycles with 200 μA during 30 s followed by 30 s Off; and C: twenty 1-min cycles with 600 μA during 10s followed by 50s Off) (n=8 for each protocol with each concentration). Skin blood flow was quantified using laser Doppler imaging and skin resistance was calculated with Ohm's law. All protocols induced a significant increase in skin blood flow. At the lower concentration (0.064 mM treprostinil) the pulsed 10/50 sequence significantly enhanced cutaneous blood flow (Table 1; Fig. 1B) compared to continuous iontophoresis or the 30/30 sequence. We noted that the pulsed iontophoresis of NaCl (10/50 sequence) induced a significant early increase in cutaneous blood flow in comparison with continuous iontophoresis. Skin resistance measures were negatively correlated with current intensity delivered. In conclusion, pulsed iontophoresis of treprostinil with a 10 s/50 s (On/Off) protocol at 600 μA increases the efficacy of iontophoresis at 0.064 mM but not at a tenfold higher concentration. Pulsed iontophoresis could be used to optimize treprostinil iontophoresis, to provide similar efficacy with decreased costs, and should now be tested on humans. Copyright © 2015 Elsevier B.V. All rights reserved.

Flow Pathways of Snow and Ground Ice Melt Water During Initial Seasonal Thawing of the Active Layer on Continuous Permafrost

NASA Astrophysics Data System (ADS)

Sjoberg, Y.; Johansson, E.; Rydberg, J.

2017-12-01

In most arctic environments, the snowmelt is the main hydrologic event of the year as a large fraction of annual precipitation rapidly moves through the catchment. Flow can occur on top of the frozen ground surface or through the developing active layer, and flow pathways are critical determinants for biogeochemical transport. We study the linkages between micro topography, active layer thaw, and water partitioning on a hillslope in Greenland during late snowmelt season to explore how seasonal subsurface flow pathways develop. During snowmelt, a parallel surface drainage pattern appears across the slope, consisting of small streams, and water also collects in puddles across the slope. Thaw rates in the active layer were significantly higher (T-test p<0.01) on wet parts of the slope (0.8 cm/day), compared to drier parts of the slope (0.6 cm/day). Analyses of stable water isotopic composition show that snow had the lightest isotopic signatures, but with a large spread of values, while seasonally frozen ground and standing surface water (puddles) were heavier. The stream water became heavier over the two-week sampling period, suggesting an increasing fraction of melted soil water input over time. In contrast, standing surface water (puddles) isotopic composition did not change over time. In boreal catchments, seasonal frost has previously been found to not significantly influence flow pathways during most snowmelt events, and pre-event groundwater make out most of the stream water during snowmelt. Our results from a continuous permafrost environment show that both surface (overland) and subsurface flow pathways in the active layer are active, and that a large fraction of the water moving on the hillslope comes from melted ground ice rather than snow in the late snowmelt season. This suggests a possibility that flow pathways during snowmelt could shift to deeper subsurface flow following degradation of continuous permafrost.

Development of Long-Lifetime Pulsed Gas Valves for Pulsed Electric Thrusters

NASA Technical Reports Server (NTRS)

Burkhardt, Wendel M.; Crapuchettes, John M.; Addona, Brad M.; Polzin, Kurt A.

2015-01-01

The design and test results for two types of pulsed gas valves are presented. The valves, a piezo valve and a solenoid actuated valve, must have exceedingly long lifetime to support gas-fed pulsed electric thruster operation for missions of interest. The performance of both valves was tested, with both demonstrating the capability to throttle the gas flow rate while maintaining low leakage levels below 10(exp -3) sccs of He at the beginning of valve lifetime. The piezo valve varies the flow rate by changing the amount that the valve is open, which is a function of applied voltage. This valve demonstrated continuous throttlability from 0-10 mL/s, with opening and closing times of 100 microsecond or less. The solenoid actuated valve flow rate changes as a function of the inlet gas pressure, with demonstrated flow rates in these tests from 2.7-11 mL per second. The valve response time is slower than the piezo valve, opening in 1-2 ms and closing in several ms. The solenoid actuated valve was tested to one million cycles, with the valve performance remaining relatively unchanged throughout the test. Galling of the sliding plunger caused the valve to bind and fail just after one million cycles, but at this point in the test the valve sealing surface leak rate still appeared to be well below the maximum target leak rake of 1×10(exp -3) sccs of He.

Use of Activated Carbon for Treatment of Explosives- Contaminated Groundwater at the Milan Army Ammunition Plant (MAAP). Task Order 7

DTIC Science & Technology

1990-05-01

Officer •" COSATI CODES 18. SUBJECT TERMS (Conrrnue on ,....e._ r# ,.cesury •trd .O.nrrfy 0, OJoclr number/ . I FIELD GROUP SUB- GROUP TN’I...hazardous waste. Cost-effectiveness of carbon adsorption is reduced both by the cost of such disposal and by the continuing replacement cost of virgin ...preferential adsorption of component groups . Based on these criteria, two carbon types were selected for continuous flow pilot testing. Groundwater

Effects of carbon brush anode size and loading on microbial fuel cell performance in batch and continuous mode

NASA Astrophysics Data System (ADS)

Lanas, Vanessa; Ahn, Yongtae; Logan, Bruce E.

2014-02-01

Larger scale microbial fuel cells (MFCs) require compact architectures to efficiently treat wastewater. We examined how anode-brush diameter, number of anodes, and electrode spacing affected the performance of the MFCs operated in fed-batch and continuous flow mode. All anodes were initially tested with the brush core set at the same distance from the cathode. In fed-batch mode, the configuration with three larger brushes (25 mm diameter) produced 80% more power (1240 mW m-2) than reactors with eight smaller brushes (8 mm) (690 mW m-2). The higher power production by the larger brushes was due to more negative and stable anode potentials than the smaller brushes. The same general result was obtained in continuous flow operation, although power densities were reduced. However, by moving the center of the smaller brushes closer to the cathode (from 16.5 to 8 mm), power substantially increased from 690 to 1030 mW m-2 in fed batch mode. In continuous flow mode, power increased from 280 to 1020 mW m-2, resulting in more power production from the smaller brushes than the larger brushes (540 mW m-2). These results show that multi-electrode MFCs can be optimized by selecting smaller anodes, placed as close as possible to the cathode.

Testing of Flame Screens and Flame Arresters as Devices Designed to Prevent the Passage of Flame (DPPF) into Tanks Containing Flammable Atmospheres According to an IMO Standard

DTIC Science & Technology

1989-10-01

flashback tests FM does not speci- fy the type of enclosure to contain the explosive fuel/air mix -ture. 3.4 INTERNATIONAL CONVENTION FOR THE SAFETY OF...2) Continuous burn tests: ... "Same mix - ture and concentration as for explosion tests; flow rate of the gasoline vapor-air mixture is specified as a...gas temperature of the flammable hexane/air mix - ture on the tank side was used as the representative endu ance burn test temperature for the following

Flow in a porous nozzle with massive wall injection

NASA Technical Reports Server (NTRS)

Kinney, R. B.

1973-01-01

An analytical and experimental investigation has been conducted to determine the effect of massive wall injection on the flow characteristics in a nozzle. The experiments were performed on a water table with a porous-nozzle test section. This had 45 deg and 15 deg half angles of convergence and divergence, respectively, throat radius of 2.5 inches, and throat width of 3 inches. The hydraulic analogy was employed to qualitatively extend the results to a compressible gas flow through the nozzle. An analysis of the water table flow was made using a one-dimensional flow assumption in the continuity and momentum equations. An analysis of a compressible flow in a nozzle was made in a manner analogous to that for the water flow. It is shown that the effect of blowing is to move the sonic position downstream of the geometric throat. Similar results were determined for the incompressible water table flow. Limited photographic results are presented for an injection of air, CO2, and Freon-12 into a main-stream air flow in a convergent-divergent nozzle. Schlieren photographs were used to visualize the flow.

Continuous Flow Science in an Undergraduate Teaching Laboratory: Photocatalytic Thiol-Ene Reaction Using Visible Light

ERIC Educational Resources Information Center

Santandrea, Jeffrey; Kairouz, Vanessa; Collins, Shawn K.

2018-01-01

An undergraduate teaching laboratory experiment involving a continuous flow, photocatalytic thiol-ene reaction using visible-light irradiation is described that allows students to explore concepts of green chemistry, photochemistry, photocatalysis, and continuous flow chemistry.

Modeling the Hot Tensile Flow Behaviors at Ultra-High-Strength Steel and Construction of Three-Dimensional Continuous Interaction Space for Forming Parameters

NASA Astrophysics Data System (ADS)

Quan, Guo-zheng; Zhan, Zong-yang; Wang, Tong; Xia, Yu-feng

2017-01-01

The response of true stress to strain rate, temperature and strain is a complex three-dimensional (3D) issue, and the accurate description of such constitutive relationships significantly contributes to the optimum process design. To obtain the true stress-strain data of ultra-high-strength steel, BR1500HS, a series of isothermal hot tensile tests were conducted in a wide temperature range of 973-1,123 K and a strain rate range of 0.01-10 s-1 on a Gleeble 3800 testing machine. Then the constitutive relationships were modeled by an optimally constructed and well-trained backpropagation artificial neural network (BP-ANN). The evaluation of BP-ANN model revealed that it has admirable performance in characterizing and predicting the flow behaviors of BR1500HS. A comparison on improved Arrhenius-type constitutive equation and BP-ANN model shows that the latter has higher accuracy. Consequently, the developed BP-ANN model was used to predict abundant stress-strain data beyond the limited experimental conditions. Then a 3D continuous interaction space for temperature, strain rate, strain and stress was constructed based on these predicted data. The developed 3D continuous interaction space for hot working parameters contributes to fully revealing the intrinsic relationships of BR1500HS steel.

Space fabrication demonstration system. [beam builder and induction fastening

NASA Technical Reports Server (NTRS)

1980-01-01

The development effort on the composite beam cap fabricator was completed within cost and close to abbreviated goals. The design and analysis of flight weight primary and secondary beam builder structures proceeded satisfactorily but remains curtailed until further funding is made available to complete the work. The induction fastening effort remains within cost and schedule constraints. Tests of the LARC prototype induction welder is continuing in an instrumented test stand comprised of a Dumore drill press (air over oil feed for variable applied loads) and a dynamometer to measure actual welding loads. Continued testing shows that the interface screening must be well impregnated with resin to ensure proper flow when bonding graphite-acrylic lap shear samples. Specimens prepared from 0.030 inch thick graphite-polyethersulfone are also available for future induction fastening evaluation.

Development of advanced fuel cell system

NASA Technical Reports Server (NTRS)

Gitlow, B.; Meyer, A. P.; Bell, W. F.; Martin, R. E.

1978-01-01

An experimental program was conducted continuing the development effort to improve the weight, life, and performance characteristics of hydrogen-oxygen alkaline fuel cells for advanced power systems. These advanced technology cells operate with passive water removal which contributes to a lower system weight and extended operating life. Endurance evaluation of two single cells and two, two-cell plaques was continued. Three new test articles were fabricated and tested. A single cell completed 7038 hours of endurance testing. This cell incorporated a Fybex matrix, hybrid-frame, PPF anode, and a 90 Au/10 Pt cathode. This configuration was developed to extend cell life. Two cell plaques with dedicated flow fields and manifolds for all fluids did not exhibit the cell-to-cell electrolyte transfer that limited the operating life of earlier multicell plaques.

Summary electrophoretic data base on human embryonic kidney cell strain 8514

NASA Technical Reports Server (NTRS)

Plank, L. D.; Kunze, M. E.; Arquiza, M. V.; Morrison, D. R.; Todd, P. W.

1985-01-01

To properly plan the electrophoresis equipment verification test (EEVT) and continuous flow electrophoresis system (CFES) experiments with human embryonic kidney cells, first a candidate cell lot had to be chosen on the basis of electrophoretic heterogeneity, growth potential, cytogenetics, and urokinase production. Cell lot 8514 from MA Bioproducts, Inc. was chosen for this purpose, and several essential analytical electrophoresis experiments were performed to test its final suitability for these experiments.

Microgravity electrophoresis: A study of the factors that affect free-fluid separation

NASA Technical Reports Server (NTRS)

1985-01-01

Electrophoresis experiments have been performed in the microgravity environment of the Space Shuttle. Test particles (fixed human and rabbit erythrocytes) migrated as expected in a static column and test macromolecules (human serum albumin, ovalbumin, hemoglobin A, and Pneumococcus polysaccharide 6B) migrated as expected in a continuous flow apparatus. The concentrations studied exceeded those that can be used in free-fluid separation and purification processes at unit gravity.

Production of egg white protein hydrolysates with improved antioxidant capacity in a continuous enzymatic membrane reactor: optimization of operating parameters by statistical design.

PubMed

Jakovetić Tanasković, Sonja; Luković, Nevena; Grbavčić, Sanja; Stefanović, Andrea; Jovanović, Jelena; Bugarski, Branko; Knežević-Jugović, Zorica

2018-01-01

This study focuses on the influence of operating conditions on Alcalase-catalyzed egg white protein hydrolysis performed in a continuously stirred tank reactor coupled with ultrafiltration module (10 kDa). The permeate flow rate did not significantly affect the degree of hydrolysis (DH), but a significant increase in process productivity was apparent above flow rate of 1.9 cm 3 min -1 . By contrast, an increase in enzyme/substrate ( E / S ) ratio provided an increase in DH, but a negative correlation was observed between E / S ratio and productivity. The relationship between operating conditions and antioxidant properties of the hydrolysates, measured by three methods, was studied using Box-Behnken experimental design and response surface methodology. The statistical analysis showed that each variable (impeller speed, E / S ratio, and permeate flow rate) had a significant effect on the antioxidant capacity of all tested systems. Nevertheless, obtained response functions revealed that antioxidative activity measured by DPPH, ABTS and FRAP methods were affected differently by the same operating conditions. High impeller speeds and low permeate flow rates favor ABTS while high impeller speeds and high permeate flow rates had a positive effect on the DPPH scavenging activity. On the other hand, the best results obtained with FRAP method were achieved under moderate operating conditions. The integration of the reaction and ultrafiltration membrane separation in a continuous manner appears to be a right approach to improve and intensify the enzymatic process, enabling the production of peptides with desired antioxidant activity.

Performance of different PEEP valves and helmet outlets at increasing gas flow rates: a bench top study.

PubMed

Isgrò, S; Zanella, A; Giani, M; Abd El Aziz El Sayed Deab, S; Pesenti, A; Patroniti, N

2012-10-01

Aim of the paper was to assess the performance of different expiratory valves and the resistance of helmet outlet ports at increasing gas flow rates. A gas flow-meter was connected to 10 different expiratory peep valves: 1 water-seal valve, 4 precalibrated fixed PEEP valves and 5 adjustable PEEP valves. Three new valves of each brand, set at different pressure levels (5-7.5-10-12.5-15 cmH(2)O, if available), were tested at increasing gas flow rates (from 30 to 150 L/min). We measured the pressure generated just before the valves. Three different helmets sealed on a mock head were connected at the inlet port with a gas flow-meter while the outlet was left clear. We measured the pressure generated inside the helmet (due to the flow-resistance of the outlet port) at increasing gas flow rates. Adjustable valves showed a variable degree flow-dependency (increasing difference between the measured and the expected pressure at increasing flow rates), while pre-calibrated valves revealed a flow-independent behavior. Water seal valve showed low degree flow-dependency. The pressures generated by the outlet port of the tested helmets ranged from 0.02 to 2.29 cmH(2)O at the highest gas flow rate. Adjustable PEEP valves are not suggested for continuous-flow CPAP systems as their flow-dependency can lead to pressures higher than expected. Precalibrated and water seal valves exhibit the best performance. Different helmet outlet ports do not significantly affect the pressure generated during helmet CPAP. In order to avoid iatrogenic complications gas flow and pressure delivered during helmet CPAP must always be monitored.

SRM Internal Flow Tests and Computational Fluid Dynamic Analysis. Volume 3; Titan, ASRM, and Subscale Motor Analyses

NASA Technical Reports Server (NTRS)

1995-01-01

A computational fluid dynamics (CFD) analysis has been performed on the aft slot region of the Titan 4 Solid Rocket Motor Upgrade (SRMU). This analysis was performed in conjunction with MSFC structural modeling of the propellant grain to determine if the flow field induced stresses would adversely alter the propellant geometry to the extent of causing motor failure. The results of the coupled CFD/stress analysis have shown that there is a continual increase of flow field resistance at the aft slot due to the aft segment propellant grain being progressively moved radially toward the centerline of the motor port. This 'bootstrapping' effect between grain radial movement and internal flow resistance is conducive to causing a rapid motor failure.

Unsteady free surface flow in porous media: One-dimensional model equations including vertical effects and seepage face

NASA Astrophysics Data System (ADS)

Di Nucci, Carmine

2018-05-01

This note examines the two-dimensional unsteady isothermal free surface flow of an incompressible fluid in a non-deformable, homogeneous, isotropic, and saturated porous medium (with zero recharge and neglecting capillary effects). Coupling a Boussinesq-type model for nonlinear water waves with Darcy's law, the two-dimensional flow problem is solved using one-dimensional model equations including vertical effects and seepage face. In order to take into account the seepage face development, the system equations (given by the continuity and momentum equations) are completed by an integral relation (deduced from the Cauchy theorem). After testing the model against data sets available in the literature, some numerical simulations, concerning the unsteady flow through a rectangular dam (with an impermeable horizontal bottom), are presented and discussed.

A new combined nanoSIMS and continuous-flow IRMS approach to measure hydrogen isotopes from water in hydrated rhyolitic glass

NASA Astrophysics Data System (ADS)

Gatti, E.; Kitchen, N.; Newman, S.; Guan, Y.; Westgate, J.; Pearce, N. J. G.; Nikolic, D.; Eiler, J. M.

2016-12-01

The hydrogen-isotope value of water of hydration (or secondary water) preserved in rhyolitic glasses may provide significant insights regarding the climate at the time of their deposition and the impact of super-eruptions upon the environment. However, the ability of the glass to retain the environmental D/H isotopic signal after hydration needs to be tested, since modifications to the D/H systematics may result from the continuous exchange of D/H with the atmosphere or condensed water after initial glass hydration. Ideal geological archives to test whether the glass retains its original hydrogen signal are sediments in natural waters and ice cores, which preserve tephra in constrained horizons that can be independently isotopically characterised. However, tephra in marine and fresh water sediments and ice cores are often present in concentrations of the order of 1000 grains/cm3 (<5 mg of collectible material). Traditional IRMS methods require much more material ( 100-500 mg) and therefore cannot be applied. We present here a new integrated nanoSIMS and continuous flow IRMS approach to understand how water is distributed within single glass grains (diffusion profiles), quantify the time of hydration of young (Holocene) and old (Miocene) already well-characterised rhyolitic glasses, and measure the D/H ratio of the hydration water on single grains and bulk material consisting of only approximately 0.1-1 mg. The IRMS method measures the absolute abundance of hydrogen released from the sample by continuous-flow mass spectrometry. Current data indicates that the method can accurately measure a hydrogen signal from a rock sample containing at least 400 nanomoles of H2, corresponding to 70 µg of water, which translates to 1 mg of hydrous glass (>3 wt%) or 15 mg of dry ( 0.5 wt%) obsidian chips. The method can be improved by reducing the blank to <1 nmol/min and reducing capillary empty space. The bulk results obtained with the continuous-flow IRMS method will be compared to sub-micron mapping of single-grains using a high-resolution ion microprobe, the CAMECA NanoSIMS 50L, in the Microanalysis Center for Geochemistry and Cosmochemistry at California Institute of Technology, in order to define the reliability of the bulk method and assess natural variability within and among grains.

Design of an Axisymmetric Afterbody Test Case for CFD Validation

NASA Technical Reports Server (NTRS)

Disotell, Kevin J.; Rumsey, Christopher L.

2017-01-01

As identified in the CFD Vision 2030 Study commissioned by NASA, validation of advanced RANS models and scale-resolving methods for computing turbulent flow fields must be supported by continuous improvements in fundamental, high-fidelity experiments designed specifically for CFD implementation. In accordance with this effort, the underpinnings of a new test platform referred to herein as the NASA Axisymmetric Afterbody are presented. The devised body-of-revolution is a modular platform consisting of a forebody section and afterbody section, allowing for a range of flow behaviors to be studied on interchangeable afterbody geometries. A body-of-revolution offers advantages in shape definition and fabrication, in avoiding direct contact with wind tunnel sidewalls, and in tail-sting integration to facilitate access to higher Reynolds number tunnels. The current work is focused on validation of smooth-body turbulent flow separation, for which a six-parameter body has been developed. A priori RANS computations are reported for a risk-reduction test configuration in order to demonstrate critical variation among turbulence model results for a given afterbody, ranging from barely-attached to mild separated flow. RANS studies of the effects of forebody nose (with/without) and wind tunnel boundary (slip/no-slip) on the selected afterbody are presented. Representative modeling issues that can be explored with this configuration are the effect of higher Reynolds number on separation behavior, flow physics of the progression from attached to increasingly-separated afterbody flows, and the effect of embedded longitudinal vortices on turbulence structure.

Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

USGS Publications Warehouse

Meinertz, J.R.; Greseth, Shari L.; Gaikowski, M.P.; Schmidt, L.J.

2008-01-01

A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid?? is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid?? on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid??. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0??mg L- 1. The study was initiated with < 24-h-old Daphnia (1 daphnid per chamber) that were exposed to hydrogen peroxide for 21??days. Hydrogen peroxide concentrations ??? 1.25??mg L- 1 had no significant effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations ??? 0.63??mg L- 1 had no significant effect on the total number of young produced. Concentrations ??? 0.32??mg L- 1 had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at ??? 0.63??mg L- 1 for less than 21??days.

EFFECTS OF AQUEOUS AND DIETARY EXPOSURE OF DIELDRIN ON SURVIVAL, GROWTH AND BIOCONCENTRATION IN MALLARD DUCKLINGS

EPA Science Inventory

Tests were conducted to determine the effects of dieldrin in continuous-flow water and in food on survival, growth, and bioconcentration in mallard ducklings. ieldrin had no effect on survival or growth at concentrations at or below water saturation (0.2 mg/L), but tissue (lipid,...

40 CFR Table 5 to Subpart Mmmmm of... - Continuous Compliance With Emission Limits and Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... performance test. v. If you use a venturi scrubber, maintaining the daily average pressure drop across the.... Each new or reconstructed flame lamination affected source using a scrubber a. Maintain the daily average scrubber inlet liquid flow rate above the minimum value established during the performanceb...

USE OF SEMI-PERMEABLE MEMBRANE DEVICES TO MONITOR POLLUTANTS IN WATER AND ASSESS THEIR EFFECTS: A LABORATORY TEST AND FIELD VERIFICATION. (U915464)

EPA Science Inventory

Uptake of eight pesticides of different classes (organochlorines, synthetic pyrethroids, dinitroanilines, amides) by semi-permeable membrane devices (SPMDs) was studied in a laboratory continuous-flow system. After 20 days of exposure, membrane concentration factors were in th...

40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., if applicable), the temperature recorder, the vehicle cooling fan, and the heated THC analysis... diesel-cycle THC analyzer continuous sample line and filter, methanol-fueled vehicle THC, methanol and... measuring devices to zero. (i) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17...

40 CFR 86.137-94 - Dynamometer test run, gaseous and particulate emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., if applicable), the temperature recorder, the vehicle cooling fan, and the heated THC analysis... diesel-cycle THC analyzer continuous sample line and filter, methanol-fueled vehicle THC, methanol and... measuring devices to zero. (i) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17...

Experimental investigation of active rib stitch knitted architecture for flow control applications

NASA Astrophysics Data System (ADS)

Abel, Julianna M.; Mane, Poorna; Pascoe, Benjamin; Luntz, Jonathan; Brei, Diann

2010-04-01

Actively manipulating flow characteristics around the wing can enhance the high-lift capability and reduce drag; thereby, increasing fuel economy, improving maneuverability and operation over diverse flight conditions which enables longer, more varied missions. Active knits, a novel class of cellular structural smart material actuator architectures created by continuous, interlocked loops of stranded active material, produce distributed actuation that can actively manipulate the local surface of the aircraft wing to improve flow characteristics. Rib stitch active knits actuate normal to the surface, producing span-wise discrete periodic arrays that can withstand aerodynamic forces while supplying the necessary displacement for flow control. This paper presents a preliminary experimental investigation of the pressuredisplacement actuation performance capabilities of a rib stitch active knit based upon shape memory alloy (SMA) wire. SMA rib stitch prototypes in both individual form and in stacked and nestled architectures were experimentally tested for their quasi-static load-displacement characteristics, verifying the parallel and series relationships of the architectural configurations. The various configurations tested demonstrated the potential of active knits to generate the required level of distributed surface displacements while under aerodynamic level loads for various forms of flow control.

Detection of phenolic compounds in flow systems based on tyrosinase-modified reticulated vitreous carbon electrodes.

PubMed

Peña, N; Reviejo, A J; Pingarrón, J M

2001-08-03

The fabrication and performance of a reticulated vitreous carbon (RVC)-based tyrosinase flow-through electrode, in which the enzyme was covalently immobilized, is reported. The bioelectrode was tested as an amperometric detector for phenolic compounds. Variables affecting the construction of the enzyme flow-through electrode such as the RVC chemical pretreatment procedure, the enzyme immobilization method in the RVC matrix, the enzyme loading and the pH value of the buffer solution used, were optimized by flow-injection with amperometric detection. A good immobilization of the enzyme in the RVC matrix, in spite of the hydrodynamic conditions, was found. The same tyrosinase-RVC electrode could be used with no significant loss of the amperometric response for around 20 days, and reproducible responses could be achieved with different electrodes constructed in the same manner. Moreover, the operational stability of the bioelectrode was tested under continuous monitorization conditions. Calibration plots by flow injection with amperometric detection at -0.20 V were obtained for phenol, 2,4-dimethylphenol; 3-chlorophenol; 4-chlorophenol; 4-chloro-3-methylphenol and 2-aminophenol, with detection limits ranging from 2 mug l(-1) (4-chloro-3-methylphenol) to 2 mg l(-1).

Continuous aryl alcohol oxidase production under growth-limited conditions using a trickle bed reactor.

PubMed

Pardo-Planas, Oscar; Atiyeh, Hasan K; Prade, Rolf A; Müller, Michael; Wilkins, Mark R

2018-05-01

An A. nidulans strain with a pyridoxine marker was used for continuous production of aryl alcohol oxidase (AAO) in a trickle bed reactor (TBR). Modified medium with reduced zinc, no copper, and 5 g/L ascorbic acid that reduced melanin production and increased AAO productivity under growth limited conditions was used. Two air flow rates, 0.11 L/min (0.1 vvm) and 1.1 L/min (1.0 vvm) were tested. More melanin formation and reduced protein productivity were observed with air flow rate of 1.1 L/min. Three random packings were used as support for the fungus inside the TBR column, two of which were hydrophobic and one which was hydrophilic, and three different dilution rates were tested. The use of GEA BCN 030 hydrophobic packing resulted in greater AAO yield and productivity than the other packings. Increasing dilution rates favored melanin formation and citric, lactic and succinic acid accumulation, which decreased AAO yield and productivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ranjan, Devesh

Diffusion bonded heat exchangers are the leading candidates for the sCO 2 Brayton cycles in next generation nuclear power plants. Commercially available diffusion bonded heat exchangers utilize set of continuous semi-circular zigzag micro channels to increase the heat transfer area and enhance heat transfer through increased turbulence production. Such heat exchangers can lead to excessive pressure drop as well as flow maldistribution in the case of poorly designed flow distribution headers. The goal of the current project is to fabricate and test potential discontinuous fin patterns for diffusion bonded heat exchangers; which can achieve desired thermal performance at lower pressuremore » drops. Prototypic discontinuous offset rectangular and Airfoil fin surface geometries were chemically etched on to 316 stainless steel plate and sealed against an un-etched flat pate using O-ring seal emulating diffusion bonded heat exchangers. Thermal-hydraulic performance of these prototypic discontinuous fin geometries was experimentally evaluated and compared to the existing data for the continuous zigzag channels. The data generated from this project will serve as the database for future testing and validation of numerical models.« less

The dispersion of particles in a separated backward-facing step flow

NASA Astrophysics Data System (ADS)

Ruck, B.; Makiola, B.

1991-05-01

Flows in technical and natural circuits often involve a particulate phase. To measure the dynamics of suspended, naturally resident or artificially seeded particles in the flow, optical measuring techniques, e.g., laser Doppler anemometry (LDA) can be used advantageously. In this paper the dispersion of particles in a single-sided backward-facing step flow is investigated by LDA. The investigation is of relevance for both, two-phase flow problems in separated flows with the associated particle diameter range of 1-70 μm and the accuracy of LDA with tracer particles of different sizes. The latter is of interest for all LDA applications to measure continuous phase properties, where interest for experimental restraints require tracer diameters in the upper micrometer range, e.g., flame resistant particles for measurements inside reactors, cylinders, etc. For the experiments, a closed-loop wind tunnel with a step expansion was used. Part of this tunnel, the test section, was made of glass. The step had a height H=25 mm (channel height before the step 25 mm, after 50 mm, i.e., an expansion ratio of 2). The width of the channel was 500 mm. The length of the glass test section was chosen as 116 step heights. The wind tunnel, driven by a radial fan, allowed flow velocities up to 50 m/sec which is equivalent to ReH=105. Seeding was performed with particles of well-known size: 1, 15, 30, and 70 μm in diameter. As 1 μm tracers oil droplets were used, whereas for the upper micron range starch particles (density 1.500 kg/m3) were chosen. Starch particles have a spherical shape and are not soluble in cold water. Particle velocities were measured locally using a conventional 1-D LDA system. The measurements deliver the resultant ``flow'' field information stemming from different particle size classes. Thus, the particle behavior in the separated flow field can be resolved. The results show that with increasing particle size, the particle velocity field differs increasingly from the flow field of the continuous phase (inferred from the smallest tracers used). The velocity fluctuations successively decrease with increasing particle diameter. In separation zones, bigger particles have a lower mean velocity than smaller ones. The opposite holds for the streamwise portions of the particle velocity field, where bigger particles show a higher velocity. The measurements give detailed insight into the particle dynamics in separated flow regions. LDA-measured dividing streamlines and lines of zero velocity of different particle classes in the recirculation region have been plotted and compared. In LDA the use of tracer particles in the upper micrometer size range leads to erroneous determinations of continuous phase flow characteristics. It turned out that the dimensions of the measured recirculation zones are reduced with increasing particle diameter. The physical reasons for these findings (relaxation time of particles, Stokes numbers, etc.) are explained in detail.

Laser speckle imaging allows real-time intraoperative blood flow assessment during neurosurgical procedures.

PubMed

Hecht, Nils; Woitzik, Johannes; König, Susanne; Horn, Peter; Vajkoczy, Peter

2013-07-01

Currently, there is no adequate technique for intraoperative monitoring of cerebral blood flow (CBF). To evaluate laser speckle imaging (LSI) for assessment of relative CBF, LSI was performed in 30 patients who underwent direct surgical revascularization for treatment of arteriosclerotic cerebrovascular disease (ACVD), Moyamoya disease (MMD), or giant aneurysms, and in 8 control patients who underwent intracranial surgery for reasons other than hemodynamic compromise. The applicability and sensitivity of LSI was investigated through baseline perfusion and CO2 reactivity testing. The dynamics of LSI were assessed during bypass test occlusion and flow initiation procedures. Laser speckle imaging permitted robust (pseudo-) quantitative assessment of relative microcirculatory flow and standard bypass grafting resulted in significantly higher postoperative baseline perfusion values in ACVD and MMD. The applicability and sensitivity of LSI was shown by a significantly reduced CO2 reactivity in ACVD (9.6±9%) and MMD (8.5±8%) compared with control (31.2±5%; P<0.0001). In high- and intermediate-flow bypass patients, LSI was characterized by a dynamic real-time response to acute perfusion changes and ultimately confirmed a sufficient flow substitution through the bypass graft. Thus, LSI can be used for sensitive and continuous, non-invasive real-time visualization and measurement of relative cortical CBF in excellent spatial-temporal resolution.

[Application of improved regional citrate anticoagulation in continuous hemofiltration in children].

PubMed

Bai, K; Liu, C J; Fu, Y Q; Xu, F

2017-05-04

Objective: To investigate the application of regional citrate anticoagulation with calcium hemofiltration basic solution in continuous hemofiltration in children. Method: The clinical data of 18 patients with citrate anticoagulation in continuous hemofiltration in children, excluding the hepatic failure and septic shock cases, were analyzed retrospectively, from September 2015 to August 2016 in Intensive Care Unit of the Children's Hospital of Chongqing Medical University.The commercial calcium hemofiltration basic solution was used as displacement liquid . The blood gas analysis, electrolyte, four coagulation tests during the treatment and the corresponding relations of quantity of blood flow(QB), quantity of citrate flow(QCi), quantity of sodium bicarbonate flow(QSB), quantity of calcium flow(QCa), quantity of filtered solution flow (Qf) were monitored. Meanwhile, the blood gas analysis, electrolyte, four coagulation tests, useful life of filter, bleeding and clotting events internal and external before, during and after the treatments were monitored, too. And the common complications of citrate anticoagulation, such as hypocalcaemia, metabolic alkalosis, citrate accumulation and hypernatremia were observed. Result: Continuous hemofiltration was applied in 18 patients for 734.5 hours, and the average useful life of filter was (25±11)h.There was no obvious clotting event. There were 168 groups of datum of the blood gas analysis, electrolyte, four coagulation tests during the treatment and the relationships of QB, QCi, QSB, QCa, Qf had been collected. The relationships of the initial parameter settings of QB, QCi, QSB, QCa and Qf were concluded as QCi=1.8×QB, QCa=0.12×QB, QSB=0.01×Qf . There were 150 times(89.3%)of extracorporeal ionized calcium(iCa(E)(2+)) and 162 times(96.4%) of intracorporal ionized calcium(iCa(I)(2+)) reached the anticoagulation target. Although all the comparisons of Na(+) ((136.2±4.1) vs .(138.2±2.4) vs .(138.5±3.9)mmol/L), iCa(2+) ((1.07±0.11) vs .(1.21±0.12) vs .(1.17±0.09)mmol/L), HCO(3)(-) ((22±4) vs .(28±5) vs . (26±4)mmol/L) among before, during and after treatment had significant difference( F =6.414, 18.950, 19.151; P =0.002, 0.000, 0.000). Each mean parameter was within the nearly normal range, except that the HCO(3)(-) increased slightly. High HCO(3)(-) was the most common complications, which happened 87 times (51.8%) during the treatment and 11 cases(37.9%) after the treatment. There was none with refractory hypocalcemia and total ionized calcium(TCa(2+) )/iCa(2+) above 2.5, which hints the accumulation of citrate. Conclusion: The commercialized displacement liquid containing calcium can be used in RCA-CHF in children safely and simply.

Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sperber, David; Eckel, Hans-Albert; Moessinger, Peter

Laser-induced energy deposition is widely discussed as a flow control technique in supersonic transportation. In case of thermal laser-plasma upstream of a blunt body, a substantial adaptation of shock wave geometry and magnitude of wave drag is predicted. Related to the research on laser supported detonation, the paper describes the implementation of laser-sustained plasma in a supersonic Argon jet. The stable plasma state is generated by the intersection of a Q-switched Nd:YAG-laser and a continuous wave CO{sub 2}-laser beams, for ignition and maintenance of the plasma respectively. A miniature supersonic Ludwieg tube test facility generates a supersonic jet at velocitiesmore » of Mach 2.1. Modifications of the flow and plasma conditions are investigated and characterized by Schlieren flow visualisation, laser energy transmission and plasma radiation measurements. The results include the discussions of the flow field as well as the required laser and gas parameters.« less

Acoustic testing of a 1.5 pressure ratio low tip speed fan with casing tip bleed (QEP Fan B scale model)

NASA Technical Reports Server (NTRS)

Kazin, S. B.; Minzner, W. R.; Paas, J. E.

1971-01-01

A scale model of the bypass flow region of a 1.5 pressure ratio, single stage, low tip speed fan was tested with a rotor tip casing bleed slot to determine its effects on noise generation. The bleed slot was located 1/2 inch (1.3 cm) upstream of the rotor leading edge and was configured to be a continuous opening around the circumference. The bleed manifold system was operated over a range of bleed rates corresponding to as much as 6% of the fan flow at approach thrust and 4.25% of the fan flow at takeoff thrust. Acoustic results indicate that a bleed rate of 4% of the fan flow reduces the fan maximum approach 200 foot (61.0 m) sideline PNL 0.5 PNdB and the corresponding takeoff thrust noise 1.1 PNdB below the level with zero bleed. However, comparison of the standard casing (no bleed slot) and the slotted bleed casing with zero bleed shows that the bleed slot itself caused a noise increase.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device.

PubMed

Gohean, Jeffrey R; George, Mitchell J; Pate, Thomas D; Kurusz, Mark; Longoria, Raul G; Smalling, Richard W

2013-01-01

The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.

Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device

PubMed Central

Gohean, Jeffrey R.; George, Mitchell J.; Pate, Thomas D.; Kurusz, Mark; Longoria, Raul G.; Smalling, Richard W.

2012-01-01

The purpose of this investigation is to utilize a computational model to compare a synchronized valveless pulsatile left ventricular assist device to continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous, pulsatile, valveless, dual piston positive displacement pump. These results were compared to measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared to the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device. PMID:23438771

Disinfection of an advanced primary effluent with peracetic acid and ultraviolet combined treatment: a continuous-flow pilot plant study.

PubMed

González, Abelardo; Gehr, Ronald; Vaca, Mabel; López, Raymundo

2012-03-01

Disinfection of an advanced primary effluent using a continuous-flow combined peracetic acid/ultraviolet (PAA/UV) radiation system was evaluated. The purpose was to determine whether the maximum microbial content, established under Mexican standards for treated wastewaters meant for reuse--less than 240 most probable number fecal coliforms (FC)/100 mL--could be feasibly accomplished using either disinfectant individually, or the combined PAA/UV system. This meant achieving reduction of up to 5 logs, considering initial concentrations of 6.4 x 10(+6) to 5.8 x 10(+7) colony forming units/100 mL. During the tests performed under these experiments, total coliforms (TC) were counted because FC, at the most, will be equal to TC. Peracetic acid disinfection achieved less than 1.5 logs TC reduction when the C(t) x t product was less than 2.26 mg x minimum (min)/L; 3.8 logs for C(t) x t 4.40 mg x min/L; and 5.9 logs for C(t) x t 24.2 mg x min/L. In continuous-flow UV irradiation tests, at a low-operating flow (21 L/min; conditions which produced an average UV fluence of 13.0 mJ/cm2), the highest TC reduction was close to 2.5 logs. The only condition that produced a disinfection efficiency of approximately 5 logs, when both disinfection agents were used together, was the combined process dosing 30 mg PAA/L at a pilot plant flow of 21 L/min and contact time of 10 minutes to attain an average C(t) x t product of 24.2 mg x min/L and an average UV fluence of 13 mJ/cm2. There was no conclusive evidence of a synergistic effect when both disinfectants were employed in combination as compared to the individual effects achieved when used separately, but this does not take into account the nonlinearity (tailing-off) of the dose-response curve.

Multiple well-shutdown tests and site-scale flow simulation in fractured rocks

USGS Publications Warehouse

Tiedeman, Claire; Lacombe, Pierre J.; Goode, Daniel J.

2010-01-01

A new method was developed for conducting aquifer tests in fractured-rock flow systems that have a pump-and-treat (P&T) operation for containing and removing groundwater contaminants. The method involves temporary shutdown of individual pumps in wells of the P&T system. Conducting aquifer tests in this manner has several advantages, including (1) no additional contaminated water is withdrawn, and (2) hydraulic containment of contaminants remains largely intact because pumping continues at most wells. The well-shutdown test method was applied at the former Naval Air Warfare Center (NAWC), West Trenton, New Jersey, where a P&T operation is designed to contain and remove trichloroethene and its daughter products in the dipping fractured sedimentary rocks underlying the site. The detailed site-scale subsurface geologic stratigraphy, a three-dimensional MODFLOW model, and inverse methods in UCODE_2005 were used to analyze the shutdown tests. In the model, a deterministic method was used for representing the highly heterogeneous hydraulic conductivity distribution and simulations were conducted using an equivalent porous media method. This approach was very successful for simulating the shutdown tests, contrary to a common perception that flow in fractured rocks must be simulated using a stochastic or discrete fracture representation of heterogeneity. Use of inverse methods to simultaneously calibrate the model to the multiple shutdown tests was integral to the effectiveness of the approach.

Correlation between lumbo-ventricular perfusion and MRI-CSF flow studies in idiopathic normal pressure hydrocephalus.

PubMed

Hakim, R; Black, P M

1998-01-01

After the initial description of normal pressure hydrocephalus (NPH) and its clinical triad, there has been a continuous interest from clinicians and researchers to set different diagnostic criteria that would make the selection of candidates for shunt surgery easier and more precise. A preliminary group of 12 patients was given a diagnosis of idiopathic normal pressure hydrocephalus by clinical and radiologic criteria. Each patient underwent two different tests: a magnetic resonance imaging-cerebrospinal fluid (MRI-CSF) flow study and a lumbo-ventricular perfusion test. The purpose was to compare the correlation of the results obtained with these tests and the clinical results obtained after CSF diversion. Eleven patients were given shunts and one was managed with lumbar punctures. One year after treatment, 10 of the 12 patients had improved with good results. The MRI-CSF flow studies were reliable in six patients; there were five false negatives and one false positive. The lumbo-ventricular perfusion test showed reliability in nine patients; there were two false negatives and one false positive. In only three patients were the results of both of these tests in accordance with the outcome. Even though there are few patients in this study so far, the data suggests that at the present time the most predictive guides for the diagnosis of NPH and its outcome after shunting are the clinical criteria and the radiological findings in computed tomography (CT) and/or MRI rather than lumbo-ventricular perfusion and CSF flow studies.

Influence of exchange group of modified glycidyl methacrylate polymer on phenol removal: A study by batch and continuous flow processes.

PubMed

Aversa, Thiago Muza; da Silva, Carla Michele Frota; da Rocha, Paulo Cristiano Silva; Lucas, Elizabete Fernandes

2016-11-01

Contamination of water by phenol is potentially a serious problem due to its high toxicity and its acid character. In this way some treatment process to remove or reduce the phenol concentration before contaminated water disposal on the environment is required. Currently, phenol can be removed by charcoal adsorption, but this process does not allow easy regeneration of the adsorbent. In contrast, polymeric resins are easily regenerated and can be reused in others cycles of adsorption process. In this work, the interaction of phenol with two polymeric resins was investigated, one of them containing a weakly basic anionic exchange group (GD-DEA) and the other, a strongly basic group (GD-QUAT). Both ion exchange resins were obtained through chemical modifications from a base porous resin composed of glycidyl methacrylate (GMA) and divinyl benzene (DVB). Evaluation tests with resins were carried out with 30 mg/L of phenol in water solution, at pH 6 and 10, employing two distinct processes: (i) batch, to evaluate the effect of temperature, and (ii) continuous flow, to assess the breakthrough of the resins. Batch tests revealed that the systems did not follow the model proposed by Langmuir due to the negative values obtained for the constant b and for the maximum adsorption capacity, Q0. However, satisfactory results for the constants KF and n allowed assuming that the behavior of systems followed the Freundlich model, leading to the conclusion that resin GD-DEA had the best interaction with the phenol when in a solution having pH 10 (phenoxide ions). The continuous flow tests corroborated this conclusion since the performance of GD-DEA in removing phenol was also best at pH 10, indicating that the greater availability of the electron pair in the resin with the weakly basic donor group contributed to enhance the resin's interaction with the phenoxide ions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Unified approach for incompressible flows

NASA Astrophysics Data System (ADS)

Chang, Tyne-Hsien

1993-12-01

An unified approach for solving both compressible and incompressible flows was investigated in this study. The difference in CFD code development between incompressible and compressible flows is due to the mathematical characteristics. However, if one can modify the continuity equation for incompressible flows by introducing pseudocompressibility, the governing equations for incompressible flows would have the same mathematical characters as compressible flows. The application of a compressible flow code to solve incompressible flows becomes feasible. Among numerical algorithms developed for compressible flows, the Centered Total Variation Diminishing (CTVD) schemes possess better mathematical properties to damp out the spurious oscillations while providing high-order accuracy for high speed flows. It leads us to believe that CTVD schemes can equally well solve incompressible flows. In this study, the governing equations for incompressible flows include the continuity equation and momentum equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. The continuity equation is modified by adding a time-derivative of the pressure term containing the artificial compressibility. The modified continuity equation together with the unsteady momentum equations forms a hyperbolic-parabolic type of time-dependent system of equations. Thus, the CTVD schemes can be implemented. In addition, the boundary conditions including physical and numerical boundary conditions must be properly specified to obtain accurate solution. The CFD code for this research is currently in progress. Flow past a circular cylinder will be used for numerical experiments to determine the accuracy and efficiency of the code before applying this code to more specific applications.

Continuous-flow liquid microjunction surface sampling probe connected on-line with high-performance liquid chromatography/mass spectrometry for spatially resolved analysis of small molecules and proteins.

PubMed

Van Berkel, Gary J; Kertesz, Vilmos

2013-06-30

A continuous-flow liquid microjunction surface sampling probe extracts soluble material from surfaces for direct ionization and detection by mass spectrometry. Demonstrated here is the on-line coupling of such a probe with high-performance liquid chromatography/mass spectrometry (HPLC/MS) enabling extraction, separation and detection of small molecules and proteins from surfaces in a spatially resolved (~0.5 mm diameter spots) manner. A continuous-flow liquid microjunction surface sampling probe was connected to a six-port, two-position valve for extract collection and injection to an HPLC column. A QTRAP® 5500 hybrid triple quadrupole linear ion trap equipped with a Turbo V™ ion source operated in positive electrospray ionization (ESI) mode was used for all experiments. The system operation was tested with the extraction, separation and detection of propranolol and associated metabolites from drug dosed tissues, caffeine from a coffee bean, cocaine from paper currency, and proteins from dried sheep blood spots on paper. Confirmed in the tissue were the parent drug and two different hydroxypropranolol glucuronides. The mass spectrometric response for these compounds from different locations in the liver showed an increase with increasing extraction time (5, 20 and 40 s). For on-line separation and detection/identification of extracted proteins from dried sheep blood spots, two major protein peaks dominated the chromatogram and could be correlated with the expected masses for the hemoglobin α and β chains. Spatially resolved sampling, separation, and detection of small molecules and proteins from surfaces can be accomplished using a continuous-flow liquid microjunction surface sampling probe coupled on-line with HPLC/MS detection. Published in 2013. This article is a U.S. Government work and is in the public domain in the USA.

Mass spectrometric real-time monitoring of an enzymatic phosphorylation assay using internal standards and data-handling freeware.

PubMed

Krappmann, Michael; de Boer, Arjen R; Kool, Daniël R W; Irth, Hubertus; Letzel, Thomas

2016-04-30

Continuous-flow reaction detection systems (monitoring enzymatic reactions with mass spectrometry (MS)) lack quantitative values so far. Therefore, two independent internal standards (IS) are implemented in a way that the online system stability can be observed, quantitative conversion values for substrate and product can be obtained and they can be used as mass calibration standards for high MS accuracy. An application previously developed for the MS detection of peptide phosphorylation by cAMP-dependent protein kinase A (PKA) (De Boer et al., Anal. Bioanal. Chem. 2005, 381, 647-655) was transferred to a continuous-flow reaction detection system. This enzymatic reaction, involving enzyme activation as well as the transfer of a phosphate group from ATP to a peptide substrate, was used to prove the compatibility of a quantitative enzymatic assay in a continuous-flow real-time system (connected to MS). Moreover (using internal standards), the critical parameter reaction temperature (including solution density variations depending on temperature) was studied in the continuous-flow mixing system. Furthermore, two substrates (malantide and kemptide), two enzyme types (catalytic subunit of PKA and complete PKA) and one inhibitor were tested to determine system robustness and long-term availability. Even spraying solutions that contained significant amount of MS contaminants (e.g. the polluted catalytic subunit) resulted in quantifiable MS signal intensities. Subsequent recalculations using the internal standards led to results representing the power of this application. The presented methodology and the data evaluation with available Achroma freeware enable the direct coupling of biochemical assays with quantitative MS detection. Monitoring changes such as temperature, reaction time, inhibition, or compound concentrations can be observed quantitatively and thus enzymatic activity can be calculated. Copyright © 2016 John Wiley & Sons, Ltd.

Uncertainty Evaluation of Computational Model Used to Support the Integrated Powerhead Demonstration Project

NASA Technical Reports Server (NTRS)

Steele, W. G.; Molder, K. J.; Hudson, S. T.; Vadasy, K. V.; Rieder, P. T.; Giel, T.

2005-01-01

NASA and the U.S. Air Force are working on a joint project to develop a new hydrogen-fueled, full-flow, staged combustion rocket engine. The initial testing and modeling work for the Integrated Powerhead Demonstrator (IPD) project is being performed by NASA Marshall and Stennis Space Centers. A key factor in the testing of this engine is the ability to predict and measure the transient fluid flow during engine start and shutdown phases of operation. A model built by NASA Marshall in the ROCket Engine Transient Simulation (ROCETS) program is used to predict transient engine fluid flows. The model is initially calibrated to data from previous tests on the Stennis E1 test stand. The model is then used to predict the next run. Data from this run can then be used to recalibrate the model providing a tool to guide the test program in incremental steps to reduce the risk to the prototype engine. In this paper, they define this type of model as a calibrated model. This paper proposes a method to estimate the uncertainty of a model calibrated to a set of experimental test data. The method is similar to that used in the calibration of experiment instrumentation. For the IPD example used in this paper, the model uncertainty is determined for both LOX and LH flow rates using previous data. The successful use of this model is then demonstrated to predict another similar test run within the uncertainty bounds. The paper summarizes the uncertainty methodology when a model is continually recalibrated with new test data. The methodology is general and can be applied to other calibrated models.

Cold Flow Testing of a Modified Subscale Model Exhaust System for a Space Based Laser

DTIC Science & Technology

2004-06-01

Abstract The aim of this research was a continued study of gas-dynamic phenomena that occurred in a set of stacked nozzles as reported by Captains...join the vacuum and test sections. The goals of this research were two fold; first, modify the original scale-model of the stacked cylindrical...Defense Advanced Research Projects Agency (DARPA), in conjunction with the Airborne Laser Laboratory, have studied the use of an Airborne Laser (ABL

Hydrocarbon liquid production via the bioCRACK process and catalytic hydroprocessing of the product oil

DOE PAGES

Schwaiger, Nickolaus; Elliott, Douglas C.; Ritzberger, Jurgen; ...

2015-01-01

Continuous hydroprocessing of liquid phase pyrolysis bio-oil, provided by BDI-BioEnergy International bioCRACK pilot plant at OMV Refinery in Schwechat/Vienna Austria was investigated. These hydroprocessing tests showed promising results using catalytic hydroprocessing strategies developed for unfractionated bio-oil. A sulfided base metal catalyst (CoMo on Al2O3) was evaluated. The bed of catalyst was operated at 400 °C in a continuous-flow reactor at a pressure of 12.1 MPa with flowing hydrogen. The condensed liquid products were analyzed and found that the hydrocarbon liquid was significantly hydrotreated so that nitrogen and sulfur were below the level of detection (<0.05), while the residual oxygen rangedmore » from 0.7 to 1.2%. The density of the products varied from 0.71 g/mL up to 0.79 g/mL with a correlated change of the hydrogen to carbon atomic ratio from 2.1 down to 1.9. The product quality remained high throughout the extended tests suggesting minimal loss of catalyst activity through the test. These tests provided the data needed to assess the quality of liquid fuel products obtained from the bioCRACK process as well as the activity of the catalyst for comparison with products obtained from hydrotreated fast pyrolysis bio-oils from fluidized-bed operation.« less

Improving the performance of immobilized β-glucosidase using a microreactor.

PubMed

Wei, Ce; Zhou, Yan; Zhuang, Wei; Li, Ganlu; Jiang, Min; Zhang, Hongman

2018-04-01

Here, we have presented a technically simple and efficient method for preparing a continuous flow microreactor by employing immobilized β-glucosidase in a silica quartz capillary tube. Developing an immobilized enzyme layer on the inner wall of the capillary tube involved the modification of the inner wall using bifunctional crosslinking agents 3-aminopropyltriethoxysilane and glutaraldehyde before attaching β-glucosidase. The microreactor afforded unique reaction capacities compared with conventional batch operational configurations. These included enhanced pH and thermal stability during storage tests, increased conversion rates of cellobiose, and reduced product inhibition. The maximum conversion rate of soluble substrate cellobiose digestion in the microreactor was 76% at 50°C and pH 4.8 when the microreactor was operated continually over 10 h at a flow rate of 7 μL/min. This was markedly contrasting to the observed conversion rate of 56% when cellobiose was digested in a conventional batch mode under the same pH and temperature conditions. Reaction inhibition by glucose was significantly reduced in the microreactor. We postulate that the increased capacity of glucose to diffuse into the continual flowing media above the immobilized enzyme layer prevents glucose from reaching inhibitory concentrations at the substrate-enzyme interface. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Informatics in radiology (infoRAD): A complete continuous-availability PACS archive server.

PubMed

Liu, Brent J; Huang, H K; Cao, Fei; Zhou, Michael Z; Zhang, Jianguo; Mogel, Greg

2004-01-01

The operational reliability of the picture archiving and communication system (PACS) server in a filmless hospital environment is always a major concern because server failure could cripple the entire PACS operation. A simple, low-cost, continuous-availability (CA) PACS archive server was designed and developed. The server makes use of a triple modular redundancy (TMR) system with a simple majority voting logic that automatically identifies a faulty module and removes it from service. The remaining two modules continue normal operation with no adverse effects on data flow or system performance. In addition, the server is integrated with two external mass storage devices for short- and long-term storage. Evaluation and testing of the server were conducted with laboratory experiments in which hardware failures were simulated to observe recovery time and the resumption of normal data flow. The server provides maximum uptime (99.999%) for end users while ensuring the transactional integrity of all clinical PACS data. Hardware failure has only minimal impact on performance, with no interruption of clinical data flow or loss of data. As hospital PACS become more widespread, the need for CA PACS solutions will increase. A TMR CA PACS archive server can reliably help achieve CA in this setting. Copyright RSNA, 2004

Continuous Flow Science in an Undergraduate Teaching Laboratory: Bleach-Mediated Oxidation in a Biphasic System

ERIC Educational Resources Information Center

Kairouz, Vanessa; Collins, Shawn K.

2018-01-01

An undergraduate teaching laboratory experiment involving a continuous flow, bleach-mediated oxidation of aldehydes under biphasic conditions was developed that allowed students to explore concepts of mixing or mass transport, solvent sustainability, biphasic reactions, phase transfer catalysis, and continuous flow chemistry.

Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.

PubMed

Cambié, Dario; Bottecchia, Cecilia; Straathof, Natan J W; Hessel, Volker; Noël, Timothy

2016-09-14

Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

Exploring the Link Between Streamflow Trends and Climate Change in Indiana, USA

NASA Astrophysics Data System (ADS)

Kumar, S.; Kam, J.; Thurner, K.; Merwade, V.

2007-12-01

Streamflow trends in Indiana are evaluated for 85 USGS streamflow gaging stations that have continuous unregulated streamflow records varying from 10 to 80 years. The trends are analyzed by using the non-parametric Mann-Kendall test with prior trend-free pre-whitening to remove serial correlation in the data. Bootstrap method is used to establish field significance of the results. Trends are computed for 12 streamflow statistics to include low-, medium- (median and mean flow), and high-flow conditions on annual and seasonal time step. The analysis is done for six study periods, ranging from 10 years to more than 65 years, all ending in 2003. The trends in annual average streamflow, for 50 years study period, are compared with annual average precipitation trends from 14 National Climatic Data Center (NCDC) stations in Indiana, that have 50 years of continuous daily record. The results show field significant positive trends in annual low and medium streamflow statistics at majority of gaging stations for study periods that include 40 or more years of records. In seasonal analysis, all flow statistics in summer and fall (low flow seasons), and only low flow statistics in winter and spring (high flow seasons) are showing positive trends. No field significant trends in annual and seasonal flow statistics are observed for study periods that include 25 or fewer years of records, except for northern Indiana where localized negative trends are observed in 10 and 15 years study periods. Further, stream flow trends are found to be highly correlated with precipitation trends on annual time step. No apparent climate change signal is observed in Indiana stream flow records.

Evaluation of a method of estimating low-flow frequencies from base-flow measurements at Indiana streams

USGS Publications Warehouse

Wilson, John Thomas

2000-01-01

A mathematical technique of estimating low-flow frequencies from base-flow measurements was evaluated by using data for streams in Indiana. Low-flow frequencies at low- flow partial-record stations were estimated by relating base-flow measurements to concurrent daily flows at nearby streamflow-gaging stations (index stations) for which low-flowfrequency curves had been developed. A network of long-term streamflow-gaging stations in Indiana provided a sample of sites with observed low-flow frequencies. Observed values of 7-day, 10-year low flow and 7-day, 2-year low flow were compared to predicted values to evaluate the accuracy of the method. Five test cases were used to evaluate the method under a variety of conditions in which the location of the index station and its drainage area varied relative to the partial-record station. A total of 141 pairs of streamflow-gaging stations were used in the five test cases. Four of the test cases used one index station, the fifth test case used two index stations. The number of base-flow measurements was varied for each test case to see if the accuracy of the method was affected by the number of measurements used. The most accurate and least variable results were produced when two index stations on the same stream or tributaries of the partial-record station were used. All but one value of the predicted 7-day, 10-year low flow were within 15 percent of the values observed for the long-term continuous record, and all of the predicted values of the 7-day, 2-year lowflow were within 15 percent of the observed values. This apparent accuracy, to some extent, may be a result of the small sample set of 15. Of the four test cases that used one index station, the most accurate and least variable results were produced in the test case where the index station and partial-record station were on the same stream or on streams tributary to each other and where the index station had a larger drainage area than the partial-record station. In that test case, the method tended to over predict, based on the median relative error. In 23 of 28 test pairs, the predicted 7-day, 10-year low flow was within 15 percent of the observed value; in 26 of 28 test pairs, the predicted 7-day, 2-year low flow was within 15 percent of the observed value. When the index station and partial-record station were on the same stream or streams tributary to each other and the index station had a smaller drainage area than the partial-record station, the method tended to under predict the low-flow frequencies. Nineteen of 28 predicted values of the 7-day, 10-year low flow were within 15 percent of the observed values. Twenty-five of 28 predicted values of the 7-day, 2-year low flow were within 15 percent of the observed values. When the index station and the partial-record station were on different streams, the method tended to under predict regardless of whether the index station had a larger or smaller drainage area than that of the partial-record station. Also, the variability of the relative error of estimate was greatest for the test cases that used index stations and partial-record stations from different streams. This variability, in part, may be caused by using more streamflow-gaging stations with small low-flow frequencies in these test cases. A small difference in the predicted and observed values can equate to a large relative error when dealing with stations that have small low-flow frequencies. In the test cases that used one index station, the method tended to predict smaller low-flow frequencies as the number of base-flow measurements was reduced from 20 to 5. Overall, the average relative error of estimate and the variability of the predicted values increased as the number of base-flow measurements was reduced.

Methods used to compute low-flow frequency characteristics for continuous-record streamflow stations in Minnesota, 2006

USGS Publications Warehouse

Winterstein, Thomas A.; Arntson, Allan D.; Mitton, Gregory B.

2007-01-01

The 1-, 7-, and 30-day low-flow series were determined for 120 continuous-record streamflow stations in Minnesota having at least 20 years of continuous record. The 2-, 5-, 10-, 50-, and 100-year statistics were determined for each series by fitting a log Pearson type III distribution to the data. The methods used to determine the low-flow statistics and to construct the plots of the low-flow frequency curves are described. The low-flow series and the low-flow statistics are presented in tables and graphs.

Exposure to noise during continuous positive airway pressure: influence of interfaces and delivery systems.

PubMed

Cavaliere, F; Conti, G; Costa, R; Spinazzola, G; Proietti, R; Sciuto, A; Masieri, S

2008-01-01

We measured noise intensity and perceived noisiness during continuous positive airway pressure (CPAP) performed with two interfaces (face-mask, helmet) and four delivery systems. Eight healthy volunteers received CPAP in random order with: two systems provided with a flow generator using the Venturi effect and a mechanical expiratory valve (A: Venturi, Starmed; B: Whisperflow-2, Caradyne Ltd); one 'free-flow' system provided with high flow O(2) and air flowmeters, an inspiratory gas reservoir, and a water valve (C: CF800, Drägerwerk, AG); and a standard mechanical ventilator (Servoventilator 300, Siemens-Elema). Systems A, B, and C were tested with a face-mask and a helmet at a CPAP value of 10 cm H(2)O; the mechanical ventilator was only tested with the face mask. Noise intensity was measured with a sound-level meter. After each test, participants scored noisiness on a visual analog scale (VAS). The noise levels measured ranged from 57+/-11 dBA (mechanical ventilator plus mask) to 93+/-1 and 94+/-2 dBA (systems A and B plus helmet) and were significantly affected by CPAP systems (A and B noisier than C and D) and interfaces (helmet CPAP noisier than mask CPAP). Subjective evaluation showed that systems A and B plus helmet were perceived as noisier than system C plus mask or helmet. Maximum noise levels observed in this study may potentially cause patient discomfort. Less noisy CPAP systems (not using Venturi effect) and interfaces (facial mask better than helmet) should be preferred, particularly for long or nocturnal treatments.

Low-temperature catalytic gasification of food processing wastes. 1995 topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, D.C.; Hart, T.R.

The catalytic gasification system described in this report has undergone continuing development and refining work at Pacific Northwest National Laboratory (PNNL) for over 16 years. The original experiments, performed for the Gas Research Institute, were aimed at developing kinetics information for steam gasification of biomass in the presence of catalysts. From the fundamental research evolved the concept of a pressurized, catalytic gasification system for converting wet biomass feedstocks to fuel gas. Extensive batch reactor testing and limited continuous stirred-tank reactor tests provided useful design information for evaluating the preliminary economics of the process. This report is a follow-on to previousmore » interim reports which reviewed the results of the studies conducted with batch and continuous-feed reactor systems from 1989 to 1994, including much work with food processing wastes. The discussion here provides details of experiments on food processing waste feedstock materials, exclusively, that were conducted in batch and continuous- flow reactors.« less

Experimental Measurements of Sonic Boom Signatures Using a Continuous Data Acquisition Technique

NASA Technical Reports Server (NTRS)

Wilcox, Floyd J.; Elmiligui, Alaa A.

2013-01-01

A wind tunnel investigation was conducted in the Langley Unitary Plan Wind Tunnel to determine the effectiveness of a technique to measure aircraft sonic boom signatures using a single conical survey probe while continuously moving the model past the probe. Sonic boom signatures were obtained using both move-pause and continuous data acquisition methods for comparison. The test was conducted using a generic business jet model at a constant angle of attack and a single model-to-survey-probe separation distance. The sonic boom signatures were obtained at a Mach number of 2.0 and a unit Reynolds number of 2 million per foot. The test results showed that it is possible to obtain sonic boom signatures while continuously moving the model and that the time required to acquire the signature is at least 10 times faster than the move-pause method. Data plots are presented with a discussion of the results. No tabulated data or flow visualization photographs are included.

Focusing-schlieren visualization in a dual-mode scramjet

NASA Astrophysics Data System (ADS)

Kouchi, Toshinori; Goyne, Christopher P.; Rockwell, Robert D.; McDaniel, James C.

2015-12-01

Schlieren imaging is particularly suited to measuring density gradients in compressible flowfields and can be used to capture shock waves and expansion fans, as well as the turbulent structures of mixing and wake flows. Conventional schlieren imaging, however, has difficulty clearly capturing such structures in long-duration supersonic combustion test facilities. This is because the severe flow temperatures locally change the refractive index of the window glass that is being used to provide optical access. On the other hand, focusing-schlieren imaging presents the potential of reduced sensitivity to thermal distortion of the windows and to clearly capture the flow structures even during a combustion test. This reduced sensitivity is due the technique's ability to achieve a narrow depth of focus. As part of this study, a focusing-schlieren system was developed with a depth of focus near ±5 mm and was applied to a direct-connect, continuous-flow type, supersonic combustion test facility with a stagnation temperature near 1200 K. The present system was used to successfully visualize the flowfield inside a dual-mode scramjet. The imaging system captured combustion-induced volumetric expansion of the fuel jet and an anchored bifurcated shock wave at the trailing edge of the ramp fuel injector. This is the first time successful focusing-schlieren measurements have been reported for a dual-mode scramjet.

Design and evaluation of thrust vectored nozzles using a multicomponent thrust stand

NASA Technical Reports Server (NTRS)

Carpenter, Thomas W.; Blattner, Ernest W.; Stagner, Robert E.; Contreras, Juanita; Lencioni, Dennis; Mcintosh, Greg

1990-01-01

Future aircraft with the capability of short takeoff and landing, and improved maneuverability especially in the post-stall flight regime will incorporate exhaust nozzles which can be thrust vectored. In order to conduct thrust vector research in the Mechanical Engineering Department at Cal Poly, a program was planned with two objectives; design and construct a multicomponent thrust stand for the specific purpose of measuring nozzle thrust vectors; and to provide quality low moisture air to the thrust stand for cold flow nozzle tests. The design and fabrication of the six-component thrust stand was completed. Detailed evaluation tests of the thrust stand will continue upon the receipt of one signal conditioning option (-702) for the Fluke Data Acquisition System. Preliminary design of thrust nozzles with air supply plenums were completed. The air supply was analyzed with regard to head loss. Initial flow visualization tests were conducted using dual water jets.

Effects of intermittent flow and irradiance level on back reef Porites corals at elevated seawater temperatures

USGS Publications Warehouse

Smith, L.W.; Birkeland, C.

2007-01-01

Corals inhabiting shallow back reef habitats are often simultaneously exposed to elevated seawater temperatures and high irradiance levels, conditions known to cause coral bleaching. Water flow in many tropical back reef systems is tidally influenced, resulting in semi-diurnal or diurnal flow patterns. Controlled experiments were conducted to test effects of semi-diurnally intermittent water flow on photoinhibition and bleaching of the corals Porites lobata and P. cylindrica kept at elevated seawater temperatures and different irradiance levels. All coral colonies were collected from a shallow back reef pool on Ofu Island, American Samoa. In the high irradiance experiments, photoinhibition and bleaching were less for both species in the intermittent high-low flow treatment than in the constant low flow treatment. In the low irradiance experiments, there were no differences in photoinhibition or bleaching for either species between the flow treatments, despite continuously elevated seawater temperatures. These results suggest that intermittent flow associated with semi-diurnal tides, and low irradiances caused by turbidity or shading, may reduce photoinhibition and bleaching of back reef corals during warming events. ?? 2006 Elsevier B.V. All rights reserved.

Effects of UV irradiation in a continuous turbulent flow UV reactor on microbiological and sensory characteristics of cow's milk.

PubMed

Rossitto, P V; Cullor, J S; Crook, J; Parko, J; Sechi, P; Cenci-Goga, B T

2012-12-01

The dairy industry under current pasteurization conditions (15 s at 72°C) and sanitary standards achieves a safe product with excellent quality. In an ever-competitive market there is still a need to improve product quality and extend shelf life of dairy products to increase competitiveness and open up new markets. In an attempt to test the effect of UV irradiation on microbiota of fluid milk, a continuous flow UV system at 254 nm was used to treat 3.5 and 2% fat milk at two UV doses (880 and 1,760 J liter(-1)). Milk was obtained from three processors, and two lots from each processor were assessed. To assess the impact on the most descriptive native microbiota in pasteurized milk after UV illumination, the product was held at two storage temperatures (4 and 7°C) and tested weekly for 5 weeks for aerobic plate counts (psychrotrophic and mesophilic bacteria), laboratory pasteurization counts, aerobic sporeformers, coliform organisms, and titratable acidity. Microbial counts for all tested microorganisms were lower in UV-treated milk when compared with control throughout storage at 4 and 7°C in both 3.5 and 2% fat milk. Sensory analysis indicated that there is a sensory defect associated with UV treatment at the wavelength used.

Continuous and Pulsatile Pediatric Ventricular Assist Device Hemodynamics with a Viscoelastic Blood Model

PubMed Central

Good, Bryan C.; Deutsch, Steven; Manning, Keefe B.

2015-01-01

Purpose To investigate the effects of pulsatile and continuous pediatric ventricular assist (PVAD) flow and pediatric blood viscoelasticity on hemodynamics in a pediatric aortic graft model. Methods Hemodynamic parameters of pulsatility, along with velocity and wall shear stress (WSS), are analyzed and compared between Newtonian and viscoelastic blood models at a range of physiological pediatric hematocrits using computational fluid dynamics. Results Both pulsatile and continuous PVAD flow lead to a decrease in pulsatility (surplus hemodynamic energy (SHE), ergs/cm3) compared to healthy aortic flow but with continuous PVAD pulsatility up to 2.4 times lower than pulsatile PVAD pulsatility at each aortic outlet. Significant differences are also seen between the two flow modes in velocity and WSS. The higher velocity jet during systole with pulsatile flow leads to higher WSSs at the anastomotic toe and at the aortic branch bifurcations. The lower velocity but continuous flow jet leads to a much different flow field and higher WSSs into diastole. Under a range of physiological pediatric hematocrit (20-60%), both velocity and WSS can vary significantly with the higher hematocrit blood model generally leading to higher peak WSSs but also lower WSSs in regions of flow separation. Conclusions The large decrease in pulsatility seen from continuous PVAD flow could lead to complications in pediatric vascular development while the high WSSs during peak systole from pulsatile PVAD flow could lead to blood damage. Both flow modes lead to similar regions prone to intimal hyperplasia (IH) resulting from low time-averaged WSS (TAWSS) and high oscillatory shear index (OSI). PMID:26643646

Effect of the load size on the efficiency of microwave heating under stop flow and continuous flow conditions.

PubMed

Patil, Narendra G; Rebrov, Evgeny V; Eränen, Kari; Benaskar, Faysal; Meuldijk, Jan; Mikkola, Jyri-Pekka; Hessel, Volker; Hulshof, Lumbertus A; Murzin, Dmitry Yu; Schouten, Jaap C

2012-01-01

A novel heating efficiency analysis of the microwave heated stop-flow (i.e. stagnant liquid) and continuous-flow reactors has been presented. The thermal losses to the surrounding air by natural convection have been taken into account for heating efficiency calculation of the microwave heating process. The effect of the load diameter in the range of 4-29 mm on the heating efficiency of ethylene glycol was studied in a single mode microwave cavity under continuous flow and stop-flow conditions. The variation of the microwave absorbing properties of the load with temperature was estimated. Under stop-flow conditions, the heating efficiency depends on the load diameter. The highest heating efficiency has been observed at the load diameter close to the half wavelength of the electromagnetic field in the corresponding medium. Under continuous-flow conditions, the heating efficiency increased linearly. However, microwave leakage above the propagation diameter restricted further experimentation at higher load diameters. Contrary to the stop-flow conditions, the load temperature did not raise monotonously from the inlet to outlet under continuous-flow conditions. This was due to the combined effect of lagging convective heat fluxes in comparison to volumetric heating. This severely disturbs the uniformity of the electromagnetic field in the axial direction and creates areas of high and low field intensity along the load Length decreasing the heating efficiency as compared to stop-flow conditions.

Development of a multiple-parameter nonlinear perturbation procedure for transonic turbomachinery flows: Preliminary application to design/optimization problems

NASA Technical Reports Server (NTRS)

Stahara, S. S.; Elliott, J. P.; Spreiter, J. R.

1983-01-01

An investigation was conducted to continue the development of perturbation procedures and associated computational codes for rapidly determining approximations to nonlinear flow solutions, with the purpose of establishing a method for minimizing computational requirements associated with parametric design studies of transonic flows in turbomachines. The results reported here concern the extension of the previously developed successful method for single parameter perturbations to simultaneous multiple-parameter perturbations, and the preliminary application of the multiple-parameter procedure in combination with an optimization method to blade design/optimization problem. In order to provide as severe a test as possible of the method, attention is focused in particular on transonic flows which are highly supercritical. Flows past both isolated blades and compressor cascades, involving simultaneous changes in both flow and geometric parameters, are considered. Comparisons with the corresponding exact nonlinear solutions display remarkable accuracy and range of validity, in direct correspondence with previous results for single-parameter perturbations.

Isotope ratio mass spectrometry in nutrition research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luke, A.H.

Many of the biochemical pathways and processes that form the foundation of modern nutrition research was elucidated using stable isotopes as physiological tracers. Since the discovery of stable isotopes, improvements and innovations in mass spectrometry and chromatography have led to greatly expanded applications. This research project was designed to evaluate gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) as a tool for isotopic tracer studies and to delineate the operational parameters for the analysis of {sup 13}C-labeled cholesterol, leucine and {alpha}-ketoisocaproate. The same isotope ratio mass spectrometer was then used as the base instrument for the ratio mass spectrometer was then usedmore » as the base instrument for the development of two additional inlet systems: a continuous-flow inlet for the analyses of {sup 13}C and {sup 18}O as CO{sub 2} and a filament inlet for on-line combustion and isotopic analysis of non-volatile organic compounds. Each of these three inlets was evaluated and their utility in nutrition research illustrated. GC/C/IRMS was used to analyze cholesterol, leucine and {alpha}-ketoisocaproate with good accuracy, precision and little isotopic memory. For all three compounds the detection limits achieved well surpassed currently used technologies. For compounds that can be well separated by GC, GC/C/IRMS is a valuable analytical tool. The continuous-flow inlet provided good accuracy and precision for measurements of {sup 13}CO{sub 2} from breath tests and {sup 18}O as CO{sub 2} from total energy expenditure tests. Most importantly, the continuous-flow inlet increased sample throughput by at least a factor of three over conventional analytical techniques. The filament inlet provided accurate and precise {sup 13}C ratio measurements of both natural abundance and enriched standards of non-volatile organic compounds of physiological interest.« less

Small scale noise and wind tunnel tests of upper surface blowing nozzle flap concepts. Volume 1. Aerodynamic test results

NASA Technical Reports Server (NTRS)

Renselaer, D. J.; Nishida, R. S.; Wilkin, C. A.

1975-01-01

The results and analyses of aerodynamic and acoustic studies conducted on the small scale noise and wind tunnel tests of upper surface blowing nozzle flap concepts are presented. Various types of nozzle flap concepts were tested. These are an upper surface blowing concept with a multiple slot arrangement with seven slots (seven slotted nozzle), an upper surface blowing type with a large nozzle exit at approximately mid-chord location in conjunction with a powered trailing edge flap with multiple slots (split flow or partially slotted nozzle). In addition, aerodynamic tests were continued on a similar multi-slotted nozzle flap, but with 14 slots. All three types of nozzle flap concepts tested appear to be about equal in overall aerodynamic performance but with the split flow nozzle somewhat better than the other two nozzle flaps in the landing approach mode. All nozzle flaps can be deflected to a large angle to increase drag without significant loss in lift. The nozzle flap concepts appear to be viable aerodynamic drag modulation devices for landing.

Development and evaluation of endurance test system for ventricular assist devices.

PubMed

Sumikura, Hirohito; Homma, Akihiko; Ohnuma, Kentaro; Taenaka, Yoshiyuki; Takewa, Yoshiaki; Mukaibayashi, Hiroshi; Katano, Kazuo; Tatsumi, Eisuke

2013-06-01

We developed a novel endurance test system that can arbitrarily set various circulatory conditions and has durability and stability for long-term continuous evaluation of ventricular assist devices (VADs), and we evaluated its fundamental performance and prolonged durability and stability. The circulation circuit of the present endurance test system consisted of a pulsatile pump with a small closed chamber (SCC), a closed chamber, a reservoir and an electromagnetic proportional valve. Two duckbill valves were mounted in the inlet and outlet of the pulsatile pump. The features of the circulation circuit are as follows: (1) the components of the circulation circuit consist of optimized industrial devices, giving durability; (2) the pulsatile pump can change the heart rate and stroke length (SL), as well as its compliance using the SCC. Therefore, the endurance test system can quantitatively reproduce various circulatory conditions. The range of reproducible circulatory conditions in the endurance test circuit was examined in terms of fundamental performance. Additionally, continuous operation for 6 months was performed in order to evaluate the durability and stability. The circulation circuit was able to set up a wide range of pressure and total flow conditions using the SCC and adjusting the pulsatile pump SL. The long-term continuous operation test demonstrated that stable, continuous operation for 6 months was possible without leakage or industrial device failure. The newly developed endurance test system demonstrated a wide range of reproducible circulatory conditions, durability and stability, and is a promising approach for evaluating the basic characteristics of VADs.

Hypothermia for preventing chemotherapy-induced neuropathy - a pilot study on safety and tolerability in healthy controls.

PubMed

Bandla, Aishwarya; Sundar, Raghav; Liao, Lun-De; Sze Hui Tan, Stacey; Lee, Soo-Chin; Thakor, Nitish V; Wilder-Smith, Einar P V

2016-01-01

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect of several chemotherapeutic agents, often leading to treatment discontinuation. Up to 20% of patients treated with weekly paclitaxel experience severe CIPN and no effective treatment has been established so far. The mechanisms of CIPN damage are unclear, but are directly dose-related. We had earlier demonstrated, in rats, the influence of hypothermia in reducing nerve blood flow. Here, we hypothesize that continuous flow limb hypothermia during chemotherapy reduces the incidence and severity of CIPN, by limiting deliverance of the neurotoxic drug to the peripheral nerves. In this study, prior to assessing the effect of hypothermia in preventing CIPN in cancer subjects undergoing paclitaxel chemotherapy, we assess the safety and tolerable temperatures for limb hypothermia in healthy human subjects. In 15 healthy human subjects, hypothermia was administered as continuous flow cooling, unilaterally, via a thermoregulator setup covering the digits up to the elbow/knee, along with continuous skin temperature monitoring. Thermoregulator coolant temperatures between 25 °C and 20 °C were tested for tolerability, based on a carefully designed temperature regulation protocol, and maintained for three hours mimicking the duration of chemotherapy. Tolerability was evaluated using various safety and tolerability scores to monitor the subjects. At the end of the cooling session the healthy subjects presented without significant adverse effects, the main being brief mild skin erythema and transient numbness. Coolant temperatures as low as 22 °C were well tolerated continuously over three hours. Our results confirm the safety and tolerability of continuous flow limb hypothermia in healthy subjects. Further studies will use 22 °C thermoregulator temperature to investigate hypothermia in preventing CIPN in breast cancer patients receiving adjuvant weekly paclitaxel. This pilot study may contribute to alleviating chemotherapy dose limitation due to CIPN and increase the likelihood of success of chemotherapy.

40 CFR Table 5 to Subpart Hhhhhhh... - Operating Parameters, Operating Limits and Data Monitoring, Recording and Compliance Frequencies...

Code of Federal Regulations, 2013 CFR

2013-07-01

... conductivity Continuous Every 15 minutes 3-hour block average. Regenerative Adsorber Regeneration stream flow. Minimum total flow per regeneration cycle Continuous N/A Total flow for each regeneration cycle. Adsorber bed temperature. Maximum temperature Continuously after regeneration and within 15 minutes of...

40 CFR Table 5 to Subpart Hhhhhhh... - Operating Parameters, Operating Limits and Data Monitoring, Recording and Compliance Frequencies...

Code of Federal Regulations, 2014 CFR

2014-07-01

... conductivity Continuous Every 15 minutes 3-hour block average. Regenerative Adsorber Regeneration stream flow. Minimum total flow per regeneration cycle Continuous N/A Total flow for each regeneration cycle. Adsorber bed temperature. Maximum temperature Continuously after regeneration and within 15 minutes of...

Test Report on Three- and Six-Component Measurements on a Series of Tapered Wings of Small Aspect Ratio

NASA Technical Reports Server (NTRS)

Lange; Wacke

1948-01-01

The investigations of the reports to 4 on wings of small aspect ratio are continued. The present report deals with the results of the three- and six-component measurements and the flow pictures of the triangular wing series with the aspect ratio Lambda = 3 to Lambda = 1.

Environmental Technology Verification: Test Report of Mobile Source Emission Control Devices--Johnson Matthey PCRT2 1000, Version 2, Filter + Diesel Oxidation Catalyst

EPA Science Inventory

The Johnson Matthey PCRT2 1000, v.2 system is a partial continuously regenerating technology (PCRT) system that consists of a flow-through partial filter combined with a DOC. The system is designed for low temperature exhaust resulting from intermittent loads from medium and heav...

40 CFR 63.9020 - What performance tests and other procedures must I use?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Hydrochloric Acid Production... where: Ci, Co = Concentration of HCl or Cl2 in the gas stream at the inlet and outlet of the control...-mole. Qi, Qo = Flow rate of gas stream at the inlet and outlet of the control device(s), respectively...

Asymmetric reactions in continuous flow

PubMed Central

Mak, Xiao Yin; Laurino, Paola

2009-01-01

Summary An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed. PMID:19478913

Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique.

PubMed

Pant, H J; Sharma, V K; Shenoy, K T; Sreenivas, T

2015-03-01

An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Experimental investigation of fluvial dike breaching due to flow overtopping

NASA Astrophysics Data System (ADS)

El Kadi Abderrezzak, K.; Rifai, I.; Erpicum, S.; Archambeau, P.; Violeau, D.; Pirotton, M.; Dewals, B.

2017-12-01

The failure of fluvial dikes (levees) often leads to devastating floods that cause loss of life and damages to public infrastructure. Overtopping flows have been recognized as one of the most frequent cause of dike erosion and breaching. Fluvial dike breaching is different from frontal dike (embankments) breaching, because of specific geometry and boundary conditions. The current knowledge on the physical processes underpinning fluvial dike failure due to overtopping remains limited. In addition, there is a lack of a continuous monitoring of the 3D breach formation, limiting the analysis of the key mechanisms governing the breach development and the validation of conceptual or physically-based models. Laboratory tests on breach growth in homogeneous, non-cohesive sandy fluvial dikes due to flow overtopping have been performed. Two experimental setups have been constructed, permitting the investigation of various hydraulic and geometric parameters. Each experimental setup includes a main channel, separated from a floodplain by a dike. A rectangular initial notch is cut in the crest to initiate dike breaching. The breach development is monitored continuously using a specific developed laser profilometry technique. The observations have shown that the breach develops in two stages: first the breach deepens and widens with the breach centerline being gradually shifted toward the downstream side of the main channel. This behavior underlines the influence of the flow momentum component parallel to the dike crest. Second, the dike geometry upstream of the breach stops evolving and the breach widening continues only toward the downstream side of the main channel. The breach evolution has been found strongly affected by the flow conditions (i.e. inflow discharge in the main channel, downstream boundary condition) and floodplain confinement. The findings of this work shed light on key mechanisms of fluvial dike breaching, which differ substantially from those of dam breaching. These specific features need to be incorporated in flood risk analyses involving fluvial dike breach and failure. In addition, a well-documented, reliable data set, with a continuous high resolution monitoring of the 3D breach evolution under various flow conditions, has been gathered, which can be used for validating numerical models.

Orbital Transfer Vehicle Engine Technology High Velocity Ratio Diffusing Crossover

NASA Technical Reports Server (NTRS)

Lariviere, Brian W.

1992-01-01

High speed, high efficiency head rise multistage pumps require continuous passage diffusing crossovers to effectively convey the pumped fluid from the exit of one impeller to the inlet of the next impeller. On Rocketdyne's Orbital Transfer Vehicle (OTV), the MK49-F, a three stage high pressure liquid hydrogen turbopump, utilizes a 6.23 velocity ratio diffusing crossover. This velocity ratio approaches the diffusion limits for stable and efficient flow over the operating conditions required by the OTV system. The design of the high velocity ratio diffusing crossover was based on advanced analytical techniques anchored by previous tests of stationary two-dimensional diffusers with steady flow. To secure the design and the analytical techniques, tests were required with the unsteady whirling characteristics produced by an impeller. A tester was designed and fabricated using a 2.85 times scale model of the MK49-F turbopumps first stage, including the inducer, impeller, and the diffusing crossover. Water and air tests were completed to evaluate the large scale turbulence, non-uniform velocity, and non-steady velocity on the pump and crossover head and efficiency. Suction performance tests from 80 percent to 124 percent of design flow were completed in water to assess these pump characteristics. Pump and diffuser performance from the water and air tests were compared with the actual MK49-F test data in liquid hydrogen.

Tracing long-term vadose zone processes at the Nevada Test Site, USA

PubMed Central

Hunt, James R.; Tompson, Andrew F. B.

2010-01-01

The nuclear weapons testing programme of the USA has released radionuclides to the subsurface at the Nevada Test Site. One of these tests has been used to study the hydrological transport of radionuclides for over 25 years in groundwater and the deep unsaturated zone. Ten years after the weapon’s test, a 16 year groundwater pumping experiment was initiated to study the mobility of radionuclides from that test in an alluvial aquifer. The continuously pumped groundwater was released into an unlined ditch where some of the water infiltrated into the 200 m deep vadose zone. The pumped groundwater had well-characterized tritium activities that were utilized to trace water migration in the shallow and deep vadose zones. Within the near-surface vadose zone, tritium levels in the soil water are modelled by a simple one-dimensional, analytical wetting front model. In the case of the near-surface soils at the Cambric Ditch experimental site, water flow and salt accumulation appear to be dominated by rooted vegetation, a mechanism not included within the wetting front model. Simulation results from a two-dimensional vadose groundwater flow model illustrate the dominance of vertical flow in the vadose zone and the recharge of the aquifer with the pumped groundwater. The long-time series of hydrological data provides opportunities to understand contaminant transport processes better in the vadose zone with an appropriate level of modelling. PMID:21785525

Startup and oxygen concentration effects in a continuous granular mixed flow autotrophic nitrogen removal reactor.

PubMed

Varas, Rodrigo; Guzmán-Fierro, Víctor; Giustinianovich, Elisa; Behar, Jack; Fernández, Katherina; Roeckel, Marlene

2015-08-01

The startup and performance of the completely autotrophic nitrogen removal over nitrite (CANON) process was tested in a continuously fed granular bubble column reactor (BCR) with two different aeration strategies: controlling the oxygen volumetric flow and oxygen concentration. During the startup with the control of oxygen volumetric flow, the air volume was adjusted to 60mL/h and the CANON reactor had volumetric N loadings ranging from 7.35 to 100.90mgN/Ld with 36-71% total nitrogen removal and high instability. In the second stage, the reactor was operated at oxygen concentrations of 0.6, 0.4 and 0.2mg/L. The best condition was 0.2 mgO2/L with a total nitrogen removal of 75.36% with a CANON reactor activity of 0.1149gN/gVVSd and high stability. The feasibility and effectiveness of CANON processes with oxygen control was demonstrated, showing an alternative design tool for efficiently removing nitrogen species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Large Eddy Simulation of Transient Flow, Solidification, and Particle Transport Processes in Continuous-Casting Mold

NASA Astrophysics Data System (ADS)

Liu, Zhongqiu; Li, Linmin; Li, Baokuan; Jiang, Maofa

2014-07-01

The current study developed a coupled computational model to simulate the transient fluid flow, solidification, and particle transport processes in a slab continuous-casting mold. Transient flow of molten steel in the mold is calculated using the large eddy simulation. An enthalpy-porosity approach is used for the analysis of solidification processes. The transport of bubble and non-metallic inclusion inside the liquid pool is calculated using the Lagrangian approach based on the transient flow field. A criterion of particle entrapment in the solidified shell is developed using the user-defined functions of FLUENT software (ANSYS, Inc., Canonsburg, PA). The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern inside the liquid pool exhibits quite satisfactory agreement with the corresponding measurements. The predicted complex instantaneous velocity field is composed of various small recirculation zones and multiple vortices. The transport of particles inside the liquid pool and the entrapment of particles in the solidified shell are not symmetric. The Magnus force can reduce the entrapment ratio of particles in the solidified shell, especially for smaller particles, but the effect is not obvious. The Marangoni force can play an important role in controlling the motion of particles, which increases the entrapment ratio of particles in the solidified shell obviously.

Exit blade geometry and part-load performance of small axial flow propeller turbines: An experimental investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Punit; Nestmann, Franz

2010-09-15

A detailed experimental investigation of the effects of exit blade geometry on the part-load performance of low-head, axial flow propeller turbines is presented. Even as these turbines find important applications in small-scale energy generation using micro-hydro, the relationship between the layout of blade profile, geometry and turbine performance continues to be poorly characterized. The experimental results presented here help understand the relationship between exit tip angle, discharge through the turbine, shaft power, and efficiency. The modification was implemented on two different propeller runners and it was found that the power and efficiency gains from decreasing the exit tip angle couldmore » be explained by a theoretical model presented here based on classical theory of turbomachines. In particular, the focus is on the behaviour of internal parameters like the runner loss coefficient, relative flow angle at exit, mean axial flow velocity and net tangential flow velocity. The study concluded that the effects of exit tip modification were significant. The introspective discussion on the theoretical model's limitation and test facility suggests wider and continued experimentation pertaining to the internal parameters like inlet vortex profile and exit swirl profile. It also recommends thorough validation of the model and its improvement so that it can be made capable for accurate characterization of blade geometric effects. (author)« less

Development of a low-cost multiple diode PIV laser for high-speed flow visualization

NASA Astrophysics Data System (ADS)

Bhakta, Raj; Hargather, Michael

2017-11-01

Particle imaging velocimetry (PIV) is an optical visualization technique that typically incorporates a single high-powered laser to illuminate seeded particles in a fluid flow. Standard PIV lasers are extremely costly and have low frequencies that severely limit its capability in high speed, time-resolved imaging. The development of a multiple diode laser system consisting of continuous lasers allows for flexible high-speed imaging with a wider range of test parameters. The developed laser system was fabricated with off-the-shelf parts for approximately 500. A series of experimental tests were conducted to compare the laser apparatus to a standard Nd:YAG double-pulsed PIV laser. Steady and unsteady flows were processed to compare the two systems and validate the accuracy of the multiple laser design. PIV results indicate good correlation between the two laser systems and verifies the construction of a precise laser instrument. The key technical obstacle to this approach was laser calibration and positioning which will be discussed. HDTRA1-14-1-0070.

Propellant Feed Subsystem for a 26 kW flight arcjet propulsion system

NASA Astrophysics Data System (ADS)

Vaughan, C. E.; Morris, J. P.

1993-06-01

The USAF arcjet ATTD program demanded the development of a low-cost ammonia Propellant Feed Subsystem (PFS). A flow rate of 240 +/- 5 mg/sec during a total of ten 15-min ammonia outflows was required for the flight mission. The precision of the flow tolerance required a departure from the design of previous ammonia propellant feed systems. Since a propellant management device was not used, thermocapillary forces were explored as a means to limit outflow of liquid phase ammonia. A high energy density feedline heater with an internal wick was developed to guarantee that only gas phase propellant would reach the arcjet. A digital control algorithm was developed to implement bang-bang control of mass flow rate metered by a sonic venturi. Development tests of this system have been completed. The system is capable of continuous gas phase outflows regardless of orientation. Integrated tests with the arcjet and power conditioning unit have also been successfully completed.

Evidence for preferential flow through sandstone aquifers in Southern Wisconsin

USGS Publications Warehouse

Swanson, S.K.; Bahr, J.M.; Bradbury, K.R.; Anderson, K.M.

2006-01-01

Sandstones often escape extensive hydrogeologic characterization due to their high primary porosity and perceived homogeneity of permeability. This study provides evidence for laterally extensive, high permeability zones in the Tunnel City Group, an undeformed, Cambrian-aged sandstone unit that exists in the subsurface throughout much of central and southern Wisconsin, USA. Several discrete high-permeability zones were identified in boreholes using flow logging and slug tests, and the interconnectedness of the features was tested using a site-specific numerical model for springs in the region. Explicit incorporation of a high-permeability layer leads to improvements in the flux calibration over simulations that lack the features, thus supporting the hydraulic continuity of high-permeability zones in the sandstone aquifer over tens of kilometers. The results suggest that stratigraphically controlled heterogeneities like contrasts in lithology or bedding-plane fractures, which have been shown to strongly influence the flow of groundwater in more heterogeneous sedimentary rocks, may also deserve close examination in sandstone aquifers. ?? 2005 Elsevier B.V. All rights reserved.

Continuous-flow cardiac assistance: effects on aortic valve function in a mock loop.

PubMed

Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas

2011-12-01

As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion--with resul-tant aortic regurgitation--has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we tested a continuous-flow LVAD in a mock circulatory system (MCS) with an interposed valve. To mimic the hemodynamic characteristics of LVAD patients, we utilized an MCS in which a Jarvik 2000 LVAD was positioned at the base of a servomotor-operated piston pump (left ventricular chamber). We operated the LVAD at 8000 to 12,000 rpm, changing the speed in 1000-rpm increments. At each speed, we first varied the outflow resistance at a constant stroke volume, then varied the stroke volume at a constant outflow resistance. We measured the left ventricular pressure, aortic pressure, pump flow, and total flow, and used these values to compute the change, if any, in the aortic duty cycle (aortic valve open time) and transvalvular aortic pressure loads. Validation of the MCS was demonstrated by the simulation of physiologic pressure and flow waveforms. At increasing LVAD speeds, the mean aortic pressure load steadily increased, while the aortic duty cycle steadily decreased. Changes were consistent for each MCS experimental setting, despite variations in stroke volume and outflow resistance. Increased LVAD flow results in an impaired aortic valve-open time due to a pressure overload above the aortic valve. Such an overload may initiate structural changes, causing aortic leaflet fusion and/or regurgitation. Copyright © 2011 Elsevier Inc. All rights reserved.

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

USGS Publications Warehouse

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-01

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial-volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial-volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial-volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat-Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

Applications of immobilized catalysts in continuous flow processes.

PubMed

Kirschning, Andreas; Jas, Gerhard

2004-01-01

As part of the dramatic changes associated with automation in pharmaceutical and agrochemical research laboratories, the search for new technologies has become a major topic in the chemical community. Commonly, high-throughput chemistry is still carried out in batches whereas flow-through processes are rather restricted to production processes, despite the fact that the latter concept allows facile automation, reproducibility, safety, and process reliability. Indeed, methods and technologies are missing that allow rapid transfer from the research level to process development. Continuous flow processes are considered as a universal lever to overcome these restrictions and only recently, joint efforts between synthetic and polymer chemists and chemical engineers have resulted in the first continuous flow devices and microreactors which allow rapid preparation of compounds with minimum workup. Importantly, more and more developments combine the use of immobilized reagents and catalysts with the concept of structured continuous flow reactors. Consequently, the present article focuses on this new research field, which is located at the interface of continuous flow processes and solid-phase-bound catalysts.

Effects of intermittent theta burst stimulation on cerebral blood flow and cerebral vasomotor reactivity.

PubMed

Pichiorri, Floriana; Vicenzini, Edoardo; Gilio, Francesca; Giacomelli, Elena; Frasca, Vittorio; Cambieri, Chiara; Ceccanti, Marco; Di Piero, Vittorio; Inghilleri, Maurizio

2012-08-01

To determine whether intermittent theta burst stimulation influences cerebral hemodynamics, we investigated changes induced by intermittent theta burst stimulation on the middle cerebral artery cerebral blood flow velocity and vasomotor reactivity to carbon dioxide (CO(2)) in healthy participants. The middle cerebral artery flow velocity and vasomotor reactivity were monitored by continuous transcranial Doppler sonography. Changes in cortical excitability were tested by transcranial magnetic stimulation. In 11 healthy participants, before and immediately after delivering intermittent theta burst stimulation, we tested cortical excitability measured by the resting motor threshold and motor evoked potential amplitude over the stimulated hemisphere and vasomotor reactivity to CO(2) bilaterally. The blood flow velocity was monitored in both middle cerebral arteries throughout the experimental session. In a separate session, we tested the effects of sham stimulation under the same experimental conditions. Whereas the resting motor threshold remained unchanged before and after stimulation, motor evoked potential amplitudes increased significantly (P = .04). During and after stimulation, middle cerebral artery blood flow velocities also remained bilaterally unchanged, whereas vasomotor reactivity to CO(2) increased bilaterally (P = .04). The sham stimulation left all variables unchanged. The expected intermittent theta burst stimulation-induced changes in cortical excitability were not accompanied by changes in cerebral blood flow velocities; however, the bilateral increased vasomotor reactivity suggests that intermittent theta burst stimulation influences the cerebral microcirculation, possibly involving subcortical structures. These findings provide useful information on hemodynamic phenomena accompanying intermittent theta burst stimulation, which should be considered in research aimed at developing this noninvasive, low-intensity stimulation technique for safe therapeutic applications.

Evaluation of an Immobilized Cell Bioreactor for Degradation of Meta- and Para-Nitrobenzoate

DTIC Science & Technology

1994-01-18

AFB IWTP. 4 Shake flask tests and continuous flow, bench-scale bioreactor tests were conducted using EDA or spent CLEPO 204 as the substrate. It was...found that the shake flask cultures completely degraded EDA when it was the sole substrate. However, using spent CLEPO 204 as the substrate caused a...microorganisms isolated, Kelly 4. Erlenmeyer flasks (250 mL) were used in studies to determine the maximal growth rate of Kelly 4 at 30" C in SMSB

Antimisting Fuel (AMK) Flight Degrader Development and Aircraft Fuel System Investigation

DTIC Science & Technology

1987-02-01

Summary of Test Results 134 CV880 Support of the CID Mission 135 Comparison of the Pump/Degrader and Needle- Valve Degrader 146 Operation on Freshly Blended...Drain Valve 53 AM 33. View of Right Side of Number 3 Engine 54 34. Redundant Shutoff Valve 55 35. Bottom View of Number 3 Engine 55 36. Onboard...Supply and Regulation/Shutoff Valves 78 44. ATMP8O-1 Pump/Degrader Test Module 79 45. Fuel Flow Circuits 80 vii La LIST OF ILLUSTRATIONS (Continued

Wind tunnel wall interference

NASA Technical Reports Server (NTRS)

Newman, Perry A.; Mineck, Raymond E.; Barnwell, Richard W.; Kemp, William B., Jr.

1986-01-01

About a decade ago, interest in alleviating wind tunnel wall interference was renewed by advances in computational aerodynamics, concepts of adaptive test section walls, and plans for high Reynolds number transonic test facilities. Selection of NASA Langley cryogenic concept for the National Transonic Facility (NTF) tended to focus the renewed wall interference efforts. A brief overview and current status of some Langley sponsored transonic wind tunnel wall interference research are presented. Included are continuing efforts in basic wall flow studies, wall interference assessment/correction procedures, and adaptive wall technology.

Kidney cell electrophoresis, continuing task

NASA Technical Reports Server (NTRS)

Todd, P. W.

1985-01-01

Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated to provide ground support in the form of analytical cell electrophoresis and flow cytometry. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. Cells were prepared in suspension prior to flight in electrophoresis buffer and 10% calf serum. Electrophoretic separation proceeded in electrophoresis buffer without serum in the Continuous Flow Electrophoretic Separator, and fractions were collected into sample bags containing culture medium and concentrated serum. Fractions that yielded enough progeny cells were analyzed for morphology and electrophoretic mobility distributions. It is noted that the lowest mobility fraction studied produced higher mobility progeny while the other fractions produced progeny cells with mobilities related to the fractions from which they were collected.

Modelling crystal plasticity by 3D dislocation dynamics and the finite element method: The Discrete-Continuous Model revisited

NASA Astrophysics Data System (ADS)

Vattré, A.; Devincre, B.; Feyel, F.; Gatti, R.; Groh, S.; Jamond, O.; Roos, A.

2014-02-01

A unified model coupling 3D dislocation dynamics (DD) simulations with the finite element (FE) method is revisited. The so-called Discrete-Continuous Model (DCM) aims to predict plastic flow at the (sub-)micron length scale of materials with complex boundary conditions. The evolution of the dislocation microstructure and the short-range dislocation-dislocation interactions are calculated with a DD code. The long-range mechanical fields due to the dislocations are calculated by a FE code, taking into account the boundary conditions. The coupling procedure is based on eigenstrain theory, and the precise manner in which the plastic slip, i.e. the dislocation glide as calculated by the DD code, is transferred to the integration points of the FE mesh is described in full detail. Several test cases are presented, and the DCM is applied to plastic flow in a single-crystal Nickel-based superalloy.

Additional studies for the spectrophotometric measurement of iodine in water

NASA Technical Reports Server (NTRS)

1972-01-01

Previous work in iodine spectroscopy is briefly reviewed. Continued studies of the direct spectrophotometric determination of aqueous iodine complexed with potassium iodide show that free iodine is optimally determined at the isosbestic point for these solutions. The effects on iodine determinations of turbidity and chemical substances (in trace amounts) is discussed and illustrated. At the levels tested, iodine measurements are not significantly altered by such substances. A preliminary design for an on-line, automated iodine monitor with eventual capability of operating also as a controller was analyzed and developed in detail with respect single beam colorimeter operating at two wavelengths (using a rotating filter wheel). A flow-through sample cell allows the instrument to operate continuously, except for momentary stop flow when measurements are made. The timed automatic cycling of the system may be interrupted whenever desired, for manual operation. An analog output signal permits controlling an iodine generator.

Parallel Continuous Flow: A Parallel Suffix Tree Construction Tool for Whole Genomes

PubMed Central

Farreras, Montse

2014-01-01

Abstract The construction of suffix trees for very long sequences is essential for many applications, and it plays a central role in the bioinformatic domain. With the advent of modern sequencing technologies, biological sequence databases have grown dramatically. Also the methodologies required to analyze these data have become more complex everyday, requiring fast queries to multiple genomes. In this article, we present parallel continuous flow (PCF), a parallel suffix tree construction method that is suitable for very long genomes. We tested our method for the suffix tree construction of the entire human genome, about 3GB. We showed that PCF can scale gracefully as the size of the input genome grows. Our method can work with an efficiency of 90% with 36 processors and 55% with 172 processors. We can index the human genome in 7 minutes using 172 processes. PMID:24597675

40 CFR 89.416 - Raw exhaust gas flow.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Raw exhaust gas flow. 89.416 Section 89.416 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Procedures § 89.416 Raw exhaust gas flow. The exhaust gas flow shall be determined by one of the methods...

40 CFR 89.416 - Raw exhaust gas flow.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw exhaust gas flow. 89.416 Section 89.416 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Procedures § 89.416 Raw exhaust gas flow. The exhaust gas flow shall be determined by one of the methods...

Design, Validation, and Testing of a Hot-Film Anemometer for Hypersonic Flow

NASA Astrophysics Data System (ADS)

Sheplak, Mark

The application of constant-temperature hot-film anemometry to hypersonic flow has been reviewed and extended in this thesis. The objective of this investigation was to develop a measurement tool capable of yielding continuous, high-bandwidth, quantitative, normal mass-flux and total -temperature measurements in moderate-enthalpy environments. This research has produced a probe design that represents a significant advancement over existing designs, offering the following improvements: (1) a five-fold increase in bandwidth; (2) true stagnation-line sensor placement; (3) a two order-of-magnitude decrease in sensor volume; and (4) over a 70% increase in maximum film temperature. These improvements were achieved through substrate design, sensor placement, the use of high-temperature materials, and state -of-the-art microphotolithographic fabrication techniques. The experimental study to characterize the probe was performed in four different hypersonic wind tunnels at NASA-Langley Research Center. The initial test consisted of traversing the hot film through a Mach 6, flat-plate, turbulent boundary layer in air. The detailed static-calibration measurements that followed were performed in two different hypersonic flows: a Mach 11 helium flow and Mach 6 air flow. The final test of this thesis consisted of traversing the probe through the Mach 6 wake of a 70^ circ blunt body. The goal of this test was to determine the state (i.e., laminar or turbulent) of the wake. These studies indicate that substrate conduction effects result in instrumentation characteristics that prevent the hot-film anemometer from being used as a quantitative tool. The extension of this technique to providing quantitative information is dependent upon the development of lower thermal-conductivity substrate materials. However, the probe durability, absence of strain gauging, and high bandwidth represent significant improvements over the hot-wire technique for making qualitative measurements. Potential uses for this probe are: frequency identification for resonant flows, transition studies, turbulence detection for quiet-tunnel development and reattaching turbulent shear flows, and qualitative turbulence studies of shock-wave/turbulent boundary layer interactions.

[The Diagnostics of Detonation Flow External Field Based on Multispectral Absorption Spectroscopy Technology].

PubMed

Lü, Xiao-jing; Li, Ning; Weng, Chun-sheng

2016-03-01

Compared with traditional sampling-based sensing method, absorption spectroscopy technology is well suitable for detonation flow diagnostics, since it can provide with us fast response, nonintrusive, sensitive solution for situ measurements of multiple flow-field parameters. The temperature and concentration test results are the average values along the laser path with traditional absorption spectroscopy technology, while the boundary of detonation flow external field is unknown and it changes all the time during the detonation engine works, traditional absorption spectroscopy technology is no longer suitable for detonation diagnostics. The trend of line strength with temperature varies with different absorption lines. By increasing the number of absorption lines in the test path, more information of the non-uniform flow field can be obtained. In this paper, based on multispectral absorption technology, the reconstructed model of detonation flow external field distribution was established according to the simulation results of space-time conservation element and solution element method, and a diagnostic method of detonation flow external field was given. The model deviation and calculation error of the least squares method adopted were studied by simulation, and the maximum concentration and temperature calculation error was 20.1% and 3.2%, respectively. Four absorption lines of H2O were chosen and detonation flow was scanned at the same time. The detonation external flow testing system was set up for the valveless gas-liquid continuous pulse detonation engine with the diameter of 80 mm. Through scanning H2O absorption lines with a high frequency of 10 kHz, the on-line detection of detonation external flow was realized by direct absorption method combined with time-division multiplexing technology, and the reconstruction of dynamic temperature distribution was realized as well for the first time, both verifying the feasibility of the test method. The test results show that both of the temperature and H2O concentration rose with the arrival of detonation wave. With the increase of the vertical distance between the detonation tube nozzle and the laser path, the time of temperature and concentration coming to the peak delayed, and the temperature variation trend tended to slow down. At 20 cm from detonation tube nozzle, the maximum temperature hit 1 329 K and the maximum H2O concentration of 0.19 occurred at 4 ms after ignition. The research can provide with us the support for expanding the detonation test field with absorption spectroscopy technology, and can also help to promote the detonation mechanism research and to enhance the level of detonation engine control technology.

Body position and activity, but not heart rate, affect pump flows in patients with continuous-flow left ventricular assist devices.

PubMed

Muthiah, Kavitha; Gupta, Sunil; Otton, James; Robson, Desiree; Walker, Robyn; Tay, Andre; Macdonald, Peter; Keogh, Anne; Kotlyar, Eugene; Granger, Emily; Dhital, Kumud; Spratt, Phillip; Jansz, Paul; Hayward, Christopher S

2014-08-01

The aim of this study was to determine the contribution of pre-load and heart rate to pump flow in patients implanted with continuous-flow left ventricular assist devices (cfLVADs). Although it is known that cfLVAD pump flow increases with exercise, it is unclear if this increment is driven by increased heart rate, augmented intrinsic ventricular contraction, or enhanced venous return. Two studies were performed in patients implanted with the HeartWare HVAD. In 11 patients, paced heart rate was increased to approximately 40 beats/min above baseline and then down to approximately 30 beats/min below baseline pacing rate (in pacemaker-dependent patients). Ten patients underwent tilt-table testing at 30°, 60°, and 80° passive head-up tilt for 3 min and then for a further 3 min after ankle flexion exercise. This regimen was repeated at 20° passive head-down tilt. Pump parameters, noninvasive hemodynamics, and 2-dimensional echocardiographic measures were recorded. Heart rate alteration by pacing did not affect LVAD flows or LV dimensions. LVAD pump flow decreased from baseline 4.9 ± 0.6 l/min to approximately 4.5 ± 0.5 l/min at each level of head-up tilt (p < 0.0001 analysis of variance). With active ankle flexion, LVAD flow returned to baseline. There was no significant change in flow with a 20° head-down tilt with or without ankle flexion exercise. There were no suction events. Centrifugal cfLVAD flows are not significantly affected by changes in heart rate, but they change significantly with body position and passive filling. Previously demonstrated exercise-induced changes in pump flows may be related to altered loading conditions, rather than changes in heart rate. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Microwave and continuous flow technologies in drug discovery.

PubMed

Sadler, Sara; Moeller, Alexander R; Jones, Graham B

2012-12-01

Microwave and continuous flow microreactors have become mainstream heating sources in contemporary pharmaceutical company laboratories. Such technologies will continue to benefit from design and engineering improvements, and now play a key role in the drug discovery process. The authors review the applications of flow- and microwave-mediated heating in library, combinatorial, solid-phase, metal-assisted, and protein chemistries. Additionally, the authors provide a description of the combination of microwave and continuous flow platforms, with applications in the preparation of radiopharmaceuticals and in drug candidate development. Literature reviewed is chiefly 2000 - 2012, plus key citations from earlier reports. With the advent of microwave irradiation, reactions that normally took days to complete can now be performed in a matter of minutes. Coupled with the introduction of continuous flow microreactors, pharmaceutical companies have an easy way to improve the greenness and efficiency of many synthetic operations. The combined force of these technologies offers the potential to revolutionize discovery and manufacturing processes.

Open Thermodynamic System Concept for Fluviokarst Underground Temperature and Discharge Flow Assessments

NASA Astrophysics Data System (ADS)

Machetel, P.; Yuen, D. A.

2012-12-01

In this work, we propose to use Open Thermodynamic System (OTS) frameworks to assess temperatures and discharges of underground flows in fluviokarstic systems. The theoretical formulation is built on the first and second laws of thermodynamics. However, such assumptions would require steady states in the Control Volume to cancel the heat exchanges between underground water and embedding rocks. This situation is obviously never perfectly reached in Nature where flow discharges and temperatures vary with rainfalls, recessions and seasonal or diurnal fluctuations. First, we will shortly show that the results of a pumping test campaign on the Cent-Font (Hérault, France) fluviokarst during summer 2005 are consistent with this theoretical approach. Second, we will present the theoretical formalism of the OTS framework that leads to equation systems involving the temperatures and/or the discharges of the underground and surface flows.Third, this approach will be applied to the white (2003) conceptual model of fluviokarst, and we will present the numerical model built to assess the applicability of these assumptions. The first order of the field hydrologic properties observed at the Cent-Fonts resurgence are well described by the calculations based on this OTS framework. If this agreement is necessary, it is not sufficient to validate the method. In order to test its applicability, the mixing process has been modelized as a cooling reaction in a Continuous Stirred Tank Reactor (CSTR) for which matrix and intrusive flows are introduced continuously while effluent water is recovered at the output. The enthalpy of the various flows is conserved except for the part that exchanges heat with the embedding rocks. However the numerical model shows that in the water saturated part of the CS, the matrix flow swepts heat by convective-advective processes while temporal heat fluctuations from intrusive flows cross the CV walls. The numerical model shows that the convective flow from matrix damps the diurnal fluctuations on very short space and time scales. The case of the seasonal temperature fluctuations depends on the relative global space and time scales between the global transport properties of the fluviokarst and the fluctuations. This works shows that, under these circumstances and framework, temperature can be considered as a conservative tracer because most of the heat exchanged with the embedding rocks during non-steady periods is brought back by the convergence of matrix flows toward the CV. This mechanism cancels the effects of the heat exchanges for the diurnal fluctuations and also reduces those that are due to seasonal variations of temperature. The OTS approach may therefore bring new tools for underground fluid temperatures and discharges assessment and may also probably offer potential applications for geothermal studies. The mixing process in the fluviokarst Conduit System is analogous to a chemical reaction in a Continuous Stirred Tank Reactor (CSTR).

A novel continuous flow biosynthesis of caffeic acid phenethyl ester from alkyl caffeate and phenethanol in a packed bed microreactor.

PubMed

Wang, Jun; Gu, Shuang-Shuang; Cui, Hong-Sheng; Wu, Xiang-Yang; Wu, Fu-An

2014-04-01

Caffeic acid phenethyl ester (CAPE) is a rare natural ingredient with several biological activity, but the industrial production of CAPE using lipase-catalyzed esterification of caffeic acid (CA) and 2-phenylethanol (PE) in ionic liquids is hindered by low substrate concentrations and a long reaction time. To establish a high-efficiency bioprocess for obtaining CAPE, a novel continuous flow biosynthesis of CAPE from alkyl caffeate and PE in [Bmim][Tf2N] using a packed bed microreactor was successfully carried out. Among the tested alkyl caffeates and lipases, methyl caffeate and Novozym 435, respectively, were selected as the suitable substrate and biocatalyst. Under the optimum conditions selected using response surface methodology, a 93.21% CAPE yield was achieved in 2.5h using a packed bed microreactor, compared to 24h using a batch reactor. The reuse of Novozym 435 for 20 cycles and continuous reaction for 9 days did not result in any decrease in activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ion Exchange Technology Development in Support of the Urine Processor Assembly Precipitation Prevention Project for the International Space Station

NASA Technical Reports Server (NTRS)

Mitchell, Julie L.; Broyan, James L.; Pickering, Karen D.; Adam, Niklas; Casteel, Michael; Callaham, Michael; Carrier, Chris

2011-01-01

In support of the Urine Processor Assembly Precipitation Prevention Project (UPA PPP), multiple technologies were explored to prevent CaSO4 dot 2H2O (gypsum) precipitation during the on-orbit distillation process. Gypsum precipitation currently limits the water recovery rate onboard the International Space Station (ISS) to 70% versus the planned 85% target water recovery rate. Due to its advanced performance in removing calcium cations in pretreated augmented urine (PTAU), ion exchange was selected as one of the technologies for further development by the PPP team. A total of 12 ion exchange resins were evaluated in various equilibrium and dynamic column tests with solutions of dissolved gypsum, urine ersatz, PTAU, and PTAU brine at 85% water recovery. While initial evaluations indicated that the Purolite SST60 resin had the highest calcium capacity in PTAU (0.30 meq/mL average), later tests showed that the Dowex G26 and Amberlite FPC12H resins had the highest capacity (0.5 meq/mL average). Further dynamic column testing proved that G26 performance is +/- 10% of that value at flow rates of 0.45 and 0.79 Lph under continuous flow, and 10.45 Lph under pulsed flow. Testing at the Marshall Spaceflight Center (MSFC) integrates the ion exchange technology with a UPA ground article under flight-like pulsed flow conditions with PTAU. To date, no gypsum precipitation has taken place in any of the initial evaluations.

Space shuttle orbiter reaction control system jet interaction study

NASA Technical Reports Server (NTRS)

Rausch, J. R.

1975-01-01

The space shuttle orbiter has forward mounted and rear mounted Reaction Control Systems (RCS) which are used for orbital maneuvering and also provide control during entry and abort maneuvers in the atmosphere. The effects of interaction between the RCS jets and the flow over the vehicle in the atmosphere are studied. Test data obtained in the NASA Langley Research Center 31 inch continuous flow hypersonic tunnel at a nominal Mach number of 10.3 is analyzed. The data were obtained with a 0.01 scale force model with aft mounted RCS nozzles mounted on the sting off of the force model balance. The plume simulations were accomplished primarily using air in a cold gas simulation through scaled nozzles, however, various cold gas mixtures of Helium and Argon were also tested. The effect of number of nozzles was tested as were limited tests of combined controls. The data show that RCS nozzle exit momentum ratio is the primary correlating parameter for effects where the plume impinges on an adjacent surface and mass flow ratio is the parameter where the plume interaction is primarily with the external stream. An analytic model of aft mounted RCS units was developed in which the total reaction control moments are the sum of thrust, impingement, interaction, and cross-coupling terms.

Tracer-Test Planning Using the Efficient Hydrologic Tracer ...

EPA Pesticide Factsheets

Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed that combines basic measured field parameters (e.g., discharge, distance, cross-sectional area) in functional relationships that describe solute-transport processes related to flow velocity and time of travel. The new method applies these initial estimates for time of travel and velocity to a hypothetical continuously stirred tank reactor as an analog for the hydrologic flow system to develop initial estimates for tracer concentration and axial dispersion, based on a preset average tracer concentration. Root determination of the one-dimensional advection-dispersion equation (ADE) using the preset average tracer concentration then provides a theoretical basis for an estimate of necessary tracer mass.Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to be

EFFICIENT HYDROLOGICAL TRACER-TEST DESIGN (EHTD ...

EPA Pesticide Factsheets

Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed that combines basic measured field parameters (e.g., discharge, distance, cross-sectional area) in functional relationships that describe solute-transport processes related to flow velocity and time of travel. The new method applies these initial estimates for time of travel and velocity to a hypothetical continuously stirred tank reactor as an analog for the hydrologic flow system to develop initial estimates for tracer concentration and axial dispersion, based on a preset average tracer concentration. Root determination of the one-dimensional advection-dispersion equation (ADE) using the preset average tracer concentration then provides a theoretical basis for an estimate of necessary tracer mass.Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to

Hydraulic characteristics of, and ground-water flow in, coal-bearing rocks of southwestern Virginia

USGS Publications Warehouse

Harlow, George E.; LeCain, Gary D.

1993-01-01

This report presents the results of a study by the U.S Geological Survey, in cooperation with the Virginia Department of Mines, Minerals, and Energy, Division of Mined Land Reclamation, and the Powell River Project, to describe the hydraulic characteristics of major water-bearing zones in the coal-bearing rocks of southwestern Virginia and to develop a conceptual model of the ground-water-flow system. Aquifer testing in1987 and 1988 of 9-ft intervals in coal-exploration coreholes indicates that transmissivity decreases with increasing depth. Most rock types are permeable to a depth of approximately 100 ft; however, only coal seams are consistently permeable (transmissivity greater than 0.001 ft/d) at depths greater than 200 ft . Constant-head injection testing of rock intervals adjacent to coal seams usually indicated lower values of transmissivity than those values obtained when coal seams were isolated within the test interval; thus, large values of horizontal hydraulic conductivity at depth are associated with coal seams. Potentiometric-head measurements indicate that high topographic areas (ridges) function as recharge areas; water infiltrates through the surface, percolates into regolith, and flows downward and laterally through fractures in the shallow bedrock. Hydraulic conductivity decreases with increasing depth, and ground water flows primarily in the lateral direction along fractures or bedding planes or through coal seams. If vertical hydraulic conductivity is negligible, ground water continues to flow laterally, discharging as springs or seeps on hill slopes. Where vertical hydraulic conductivity is appreciable, groundwater follows a stair step path through the regolith, fractures, bedding planes, and coal seams, discharging to streams and (or) recharging coal seams at depth. Permeable coal seams probably underlie valleys in the region; however, aquifer-test data indicate that the horizontal hydraulic conductivity of coal is a function of depth and probably decreases under ridges because of increased overburden pressures. Ground water beneath valleys that does not discharge to streams probably flows down gradient as underflow beneath the streams. Topographic relief in the area provides large hydraulic-head differences (greater than 300 ft in some instances) for the ground-water-flow system. Transmissivity data from the range of depths tested during this study indicate that most ground-water flow takes place at moderate depths (less than 300 ft) and that little deep regional ground-water flow occurs.

Evaluation of continuous oxydesulfurization processes. Final technical report, September 1979-July 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, J.F.; Wever, D.M.

1981-07-01

Three processes developed by Pittsburgh Energy Technology Center (PETC), Ledgemont Laboratories, and Ames Laboratories for the oxydesulfurization of coal were evaluated in continuous processing equipment designed, built, and/or adapted for the purpose at the DOE-owned Multi-Use Fuels and Energy Processes Test Plant (MEP) located at TRW's Capistrano Test Site in California. The three processes differed primarily in the chemical additives (none, sodium carbonate, or ammonia), fed to the 20% to 40% coal/water slurries, and in the oxygen content of the feed gas stream. Temperature, pressure, residence time, flow rates, slurry concentration and stirrer speed were the other primary independent variables.more » The amount of organic sulfur removed, total sulfur removed and the Btu recovery were the primary dependent variables. Evaluation of the data presented was not part of the test effort.« less

76 FR 41669 - Airworthiness Directives; B/E Aerospace, Continuous Flow Passenger Oxygen Mask Assembly, Part...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-15

... Airworthiness Directives; B/E Aerospace, Continuous Flow Passenger Oxygen Mask Assembly, Part Numbers 174006... to prevent the in-line flow indicators of the oxygen mask assembly from fracturing and separating, which could inhibit oxygen flow to the masks. This condition could consequently result in occupants...

Testing random forest classification for identifying lava flows and mapping age groups on a single Landsat 8 image

NASA Astrophysics Data System (ADS)

Li, Long; Solana, Carmen; Canters, Frank; Kervyn, Matthieu

2017-10-01

Mapping lava flows using satellite images is an important application of remote sensing in volcanology. Several volcanoes have been mapped through remote sensing using a wide range of data, from optical to thermal infrared and radar images, using techniques such as manual mapping, supervised/unsupervised classification, and elevation subtraction. So far, spectral-based mapping applications mainly focus on the use of traditional pixel-based classifiers, without much investigation into the added value of object-based approaches and into advantages of using machine learning algorithms. In this study, Nyamuragira, characterized by a series of > 20 overlapping lava flows erupted over the last century, was used as a case study. The random forest classifier was tested to map lava flows based on pixels and objects. Image classification was conducted for the 20 individual flows and for 8 groups of flows of similar age using a Landsat 8 image and a DEM of the volcano, both at 30-meter spatial resolution. Results show that object-based classification produces maps with continuous and homogeneous lava surfaces, in agreement with the physical characteristics of lava flows, while lava flows mapped through the pixel-based classification are heterogeneous and fragmented including much "salt and pepper noise". In terms of accuracy, both pixel-based and object-based classification performs well but the former results in higher accuracies than the latter except for mapping lava flow age groups without using topographic features. It is concluded that despite spectral similarity, lava flows of contrasting age can be well discriminated and mapped by means of image classification. The classification approach demonstrated in this study only requires easily accessible image data and can be applied to other volcanoes as well if there is sufficient information to calibrate the mapping.

Experimental Investigation of Transverse Supersonic Gaseous Injection Enhancement Into Supersonic Flow

DTIC Science & Technology

1996-12-01

Ramp AR 2........................................................ A.2 A. 9 . Test Section, No Injection or PME Ramp...B.2 B.8. Wide Ramp AR 1 ......................................................... B.2 B. 9 . Narrow Ramp AR 2...identified as a major near-field mixing factor.5 𔄀 While work has continued in transverse injection, 7𔄂 ’ 9 later studies sought to produce greater

Experimental and theoretical investigation of the stability of stepwise pH gradients in continuous flow electrophoresis

NASA Technical Reports Server (NTRS)

Kuhn, Reinhard; Wagner, Horst; Mosher, Richard A.; Thormann, Wolfgang

1987-01-01

Isoelectric focusing in the continuous flow mode can be more quickly and economically performed by admitting a stepwise pH gradient composed of simple buffers instead of uniform mixtures of synthetic carrier ampholytes. The time-consuming formation of the pH gradient by the electric field is thereby omitted. The stability of a three-step system with arginine - morpholinoethanesulfonic acid/glycylglycine - aspartic acid is analyzed theoretically by one-dimensional computer simulation as well as experimentally at various flow rates in a continuous flow apparatus. Excellent agreement between experimental and theoretical data was obtained. This metastable configuration was found to be suitable for focusing of proteins under continuous flow conditions. The influence of various combinations of electrolytes and membranes between electrophoresis chamber and electrode compartments is also discussed.

High-bandwidth continuous-flow arc furnace

DOEpatents

Hardt, David E.; Lee, Steven G.

1996-01-01

A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics.

High-bandwidth continuous-flow arc furnace

DOEpatents

Hardt, D.E.; Lee, S.G.

1996-08-06

A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

PubMed Central

Zhao, Xinyan; Dong, Tao

2013-01-01

A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+), zinc (Zn2+), potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU) obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety. PMID:24300075

Formulation and In Vitro Release Kinetics of Mucoadhesive Blend Gels Containing Matrine for Buccal Administration.

PubMed

Chen, Xiaojin; Yan, Jun; Yu, Shuying; Wang, Pingping

2018-01-01

Enterovirus 71 (EV71) is a pathogenic factor of severe hand, foot, and mouth disease (HFMD). No vaccine or specific treatment is currently available for EV71 infection. Hence, we developed a buccal mucoadhesive gel containing matrine to protect against HFMD. Mucoadhesive gels were prepared by Carbopol 974P and were combined with Carbopol 971P, sodium carboxymethyl cellulose (CMC-Na), or hydroxypropylmethy cellulose (HPMC K100M). The formulations were characterized in terms of tensile testing and continuous flow techniques for mucoadhesion. The rheological studies and in vitro drug release characteristics were also investigated. The results showed that combinations of two polymers significantly improved mucoadhesion, especially Carbopol 974P blended with HPMC. Carbopol 974P to HPMC blend ratios of 1:1 and 2:1 induced better mucoadhesion in the tensile test and continuous flow method, respectively. The most sustained release was obtained at a Carbopol 974P to HPMC ratio of 2.5:1. A predominantly non-Fickian diffusion release mechanism was obtained. The gel containing 2.5% Carbopol 974P combined with 1% HPMC showed good mucoadhesion properties and sustained drug release.

Computing the Feasible Spaces of Optimal Power Flow Problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molzahn, Daniel K.

The solution to an optimal power flow (OPF) problem provides a minimum cost operating point for an electric power system. The performance of OPF solution techniques strongly depends on the problem’s feasible space. This paper presents an algorithm that is guaranteed to compute the entire feasible spaces of small OPF problems to within a specified discretization tolerance. Specifically, the feasible space is computed by discretizing certain of the OPF problem’s inequality constraints to obtain a set of power flow equations. All solutions to the power flow equations at each discretization point are obtained using the Numerical Polynomial Homotopy Continuation (NPHC)more » algorithm. To improve computational tractability, “bound tightening” and “grid pruning” algorithms use convex relaxations to preclude consideration of many discretization points that are infeasible for the OPF problem. Here, the proposed algorithm is used to generate the feasible spaces of two small test cases.« less

Intrapericardial denervation - Radial artery blood flow and heart rate responses to LBNP

NASA Technical Reports Server (NTRS)

Mckeever, Kenneth H.; Skidmore, Michael G.; Keil, Lanny C.; Sandler, Harold

1990-01-01

The effects of intrapericardial denervation on the radial artery blood flow velocity (RABFV) and heart rate (HR) responses to LBNP in rhesus monkeys were investigated by measuring the RABFV transcutaneously by a continuous-wave Doppler ultrasonic flowmeter in order to derive an index of forearm blood flow response to low (0 to -20 mm Hg) and high (0 to -60 mm Hg) ramp exposures during supine LBNP. Four of the eight subjects were subjected to efferent and afferent cardiac denervation. It was found that, during low levels of LBNP, monkeys with cardiac denervation exhibited no cardiopulmonary baroreceptor-mediated change in the RABFV or HR, unlike the intact animals, which showed steady decreases in RABFV during both high- and low-pressure protocols. It is suggested that forearm blood flow and HR responses to low-level LBNP, along with pharmacological challenge, are viable physiological tests for verifying the completeness of atrial and cardiopulmonary baroreceptor denervation.

The structure of evaporating and combusting sprays: Measurements and predictions

NASA Technical Reports Server (NTRS)

Shuen, J. S.; Solomon, A. S. P.; Faeth, F. M.

1983-01-01

The structure of particle-laden jets and nonevaporating and evaporating sprays was measured in order to evaluate models of these processes. Three models are being evaluated: (1) a locally homogeneous flow model, where slip between the phases is neglected and the flow is assumed to be in local thermodynamic equilibrium; (2) a deterministic separated flow model, where slip and finite interphase transport rates are considered but effects of particle/drop dispersion by turbulence and effects of turbulence on interphase transport rates are ignored; and (3) a stochastic separated flow model, where effects of interphase slip, turbulent dispersion and turbulent fluctuations are considered using random sampling for turbulence properties in conjunction with random-walk computations for particle motion. All three models use a k-e-g turbulence model. All testing and data reduction are completed for the particle laden jets. Mean and fluctuating velocities of the continuous phase and mean mixture fraction were measured in the evaporating sprays.

Computing the Feasible Spaces of Optimal Power Flow Problems

DOE PAGES

Molzahn, Daniel K.

2017-03-15

The solution to an optimal power flow (OPF) problem provides a minimum cost operating point for an electric power system. The performance of OPF solution techniques strongly depends on the problem’s feasible space. This paper presents an algorithm that is guaranteed to compute the entire feasible spaces of small OPF problems to within a specified discretization tolerance. Specifically, the feasible space is computed by discretizing certain of the OPF problem’s inequality constraints to obtain a set of power flow equations. All solutions to the power flow equations at each discretization point are obtained using the Numerical Polynomial Homotopy Continuation (NPHC)more » algorithm. To improve computational tractability, “bound tightening” and “grid pruning” algorithms use convex relaxations to preclude consideration of many discretization points that are infeasible for the OPF problem. Here, the proposed algorithm is used to generate the feasible spaces of two small test cases.« less

Numerically based design of an orifice plate flowmetering system for human respiratory flow monitoring.

PubMed

Fortuna, A O; Gurd, J R

1999-01-01

During certain medical procedures, it is important to continuously measure the respiratory flow of a patient, as lack of proper ventilation can cause brain damage and ultimately death. The monitoring of the ventilatory condition of a patient is usually performed with the aid of flowmeters. However, water and other secretions present in the expired air can build up and ultimately block a traditional, restriction-based flowmeter; by using an orifice plate flowmeter, such blockages are minimized. This paper describes the design of an orifice plate flowmetering system including, especially, a description of the numerical and computational techniques adopted in order to simulate human respiratory and sinusoidal air flow across various possible designs for the orifice plate flowmeter device. Parallel computation and multigrid techniques were employed in order to reduce execution time. The simulated orifice plate was later built and tested under unsteady sinusoidal flows. Experimental tests show reasonable agreement with the numerical simulation, thereby reinforcing the general hypothesis that computational exploration of the design space is sufficiently accurate to allow designers of such systems to use this in preference to the more traditional, mechanical prototyping techniques.

Bacterial killing by several root filling materials and methods in an ex vivo infected root canal model.

PubMed

Özcan, E; Eldeniz, A U; Arı, H

2011-12-01

To evaluate the ability of two root canal sealers (Epoxy resin-based AH Plus or polydimethylsiloxane-based GuttaFlow) and five root filling techniques (continuous wave of condensation, Thermafil, lateral condensation, matched taper single gutta-percha point, laterally condensed-matched taper gutta-percha point) to kill bacteria in experimentally infected dentinal tubules. An infected dentine block model was used. One hundred and twenty extracted, single-rooted human teeth were randomly divided into 10 test (n = 10) and 2 control (n = 10) groups. The roots, except negative controls, were infected with Enterococcus faecalis for 21 days. The root canals were then filled using the test materials and methods. Positive controls were not filled. Sterile roots were used as negative controls. Dentine powder was obtained from all root canals using gates glidden drills using a standard method. The dentine powder was diluted and inoculated into bacterial growth media. Total colony-forming units (CFU) were calculated for each sample. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U test. The epoxy resin-based sealer was effective in killing E. faecalis except when using Thermafil (P < 0.05), but the polydimethylsiloxane-based sealer was not effective in killing this microorganism except in the continuous wave group (P < 0.05). In the test model, AH Plus killed bacteria in infected dentine more effectively than GuttaFlow. The filling method was less important than the sealer material. © 2011 International Endodontic Journal.

Nitrate removal performance of Diaphorobacter nitroreducens using biodegradable plastics as the source of reducing power

NASA Astrophysics Data System (ADS)

Khan, S. T.; Nagao, Y.; Hiraishi, A.

2015-02-01

Strain NA10BT and other two strains of the denitrifying betaproteobacterium Diaphorobacter nitroreducens were studied for the performance of solid-phase denitrification (SPD) using poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and some other biodegradable plastics as the source of reducing power in wastewater treatment. Sequencing-batch SPD reactors with these organisms and PHBV granules or flakes as the substrate exhibited good nitrate removal performance. Vial tests using cultures from these parent reactors showed higher nitrate removal rates with PHBV granules (ca. 20 mg-NO3-- N g-1 [dry wt cells] h-1) than with PHBV pellets and flakes. In continuous-flow SPD reactors using strain NA10BT and PHBV flakes, nitrate was not detected even at a loading rate of 21 mg-NO3-- N L-1 h-1. This corresponded to a nitrate removal rate of 47 mg-NO3-- N g-1 (dry wt cells) h-1. In the continuous-flow reactor, the transcription level of the phaZ gene, coding for PHB depolymerase, decreased with time, while that of the nosZ gene, involved in denitrificaiton, was relatively constant. These results suggest that the bioavailability of soluble metabolites as electron donor and carbon sources increases with time in the continuous-flow SPD process, thereby having much higher nitrate removal rates than the process with fresh PHBV as the substrate.

Modeling of brittle-viscous flow using discrete particles

NASA Astrophysics Data System (ADS)

Thordén Haug, Øystein; Barabasch, Jessica; Virgo, Simon; Souche, Alban; Galland, Olivier; Mair, Karen; Abe, Steffen; Urai, Janos L.

2017-04-01

Many geological processes involve both viscous flow and brittle fractures, e.g. boudinage, folding and magmatic intrusions. Numerical modeling of such viscous-brittle materials poses challenges: one has to account for the discrete fracturing, the continuous viscous flow, the coupling between them, and potential pressure dependence of the flow. The Discrete Element Method (DEM) is a numerical technique, widely used for studying fracture of geomaterials. However, the implementation of viscous fluid flow in discrete element models is not trivial. In this study, we model quasi-viscous fluid flow behavior using Esys-Particle software (Abe et al., 2004). We build on the methodology of Abe and Urai (2012) where a combination of elastic repulsion and dashpot interactions between the discrete particles is implemented. Several benchmarks are presented to illustrate the material properties. Here, we present extensive, systematic material tests to characterize the rheology of quasi-viscous DEM particle packing. We present two tests: a simple shear test and a channel flow test, both in 2D and 3D. In the simple shear tests, simulations were performed in a box, where the upper wall is moved with a constant velocity in the x-direction, causing shear deformation of the particle assemblage. Here, the boundary conditions are periodic on the sides, with constant forces on the upper and lower walls. In the channel flow tests, a piston pushes a sample through a channel by Poisseuille flow. For both setups, we present the resulting stress-strain relationships over a range of material parameters, confining stress and strain rate. Results show power-law dependence between stress and strain rate, with a non-linear dependence on confining force. The material is strain softening under some conditions (which). Additionally, volumetric strain can be dilatant or compactant, depending on porosity, confining pressure and strain rate. Constitutive relations are implemented in a way that limits the range of viscosities. For identical pressure and strain rate, an order of magnitude range in viscosity can be investigated. The extensive material testing indicates that DEM particles interacting by a combination of elastic repulsion and dashpots can be used to model viscous flows. This allows us to exploit the fracturing capabilities of the discrete element methods and study systems that involve both viscous flow and brittle fracturing. However, the small viscosity range achievable using this approach does constraint the applicability for systems where larger viscosity ranges are required, such as folding of viscous layers of contrasting viscosities. References: Abe, S., Place, D., & Mora, P. (2004). A parallel implementation of the lattice solid model for the simulation of rock mechanics and earthquake dynamics. PAGEOPH, 161(11-12), 2265-2277. http://doi.org/10.1007/s00024-004-2562-x Abe, S., and J. L. Urai (2012), Discrete element modeling of boudinage: Insights on rock rheology, matrix flow, and evolution of geometry, JGR., 117, B01407, doi:10.1029/2011JB00855

A comparative study of behaviors of ventilated supercavities between experimental models with different mounting configurations

NASA Astrophysics Data System (ADS)

Lee, Seung-Jae; Kawakami, Ellison; Karn, Ashish; Arndt, Roger E. A.

2016-08-01

Small-scale water tunnel experiments of the phenomenon of supercavitation can be carried out broadly using two different kinds of experimental models-in the first model (forward facing model, or FFM), the incoming flow first interacts with the cavitator at front, which is connected to the strut through a ventilation pipe. The second model could have the strut and the ventilation pipe preceding the cavitator (backward facing model, or BFM). This is the continuation of a water tunnel study of the effects of unsteady flows on axisymmetric supercavities. In this study, the unwanted effect of test model configuration on supercavity shape in periodic flows was explored through a comparison of FFM and BFM models. In our experiments, it was found that periodic gust flows have only a minimal effect on the maximum diameter and the cavity length can be shortened above a certain vertical velocity of periodic flows. These findings appear to be robust regardless of the model configuration.

Bus-based park-and-ride system: a stochastic model on multimodal network with congestion pricing schemes

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Meng, Qiang

2014-05-01

This paper focuses on modelling the network flow equilibrium problem on a multimodal transport network with bus-based park-and-ride (P&R) system and congestion pricing charges. The multimodal network has three travel modes: auto mode, transit mode and P&R mode. A continuously distributed value-of-time is assumed to convert toll charges and transit fares to time unit, and the users' route choice behaviour is assumed to follow the probit-based stochastic user equilibrium principle with elastic demand. These two assumptions have caused randomness to the users' generalised travel times on the multimodal network. A comprehensive network framework is first defined for the flow equilibrium problem with consideration of interactions between auto flows and transit (bus) flows. Then, a fixed-point model with unique solution is proposed for the equilibrium flows, which can be solved by a convergent cost averaging method. Finally, the proposed methodology is tested by a network example.

Application of the Shiono and Knight Method in asymmetric compound channels with different side slopes of the internal wall

NASA Astrophysics Data System (ADS)

Alawadi, Wisam; Al-Rekabi, Wisam S.; Al-Aboodi, Ali H.

2018-03-01

The Shiono and Knight Method (SKM) is widely used to predict the lateral distribution of depth-averaged velocity and boundary shear stress for flows in compound channels. Three calibrating coefficients need to be estimated for applying the SKM, namely eddy viscosity coefficient ( λ), friction factor ( f) and secondary flow coefficient ( k). There are several tested methods which can satisfactorily be used to estimate λ, f. However, the calibration of secondary flow coefficients k to account for secondary flow effects correctly is still problematic. In this paper, the calibration of secondary flow coefficients is established by employing two approaches to estimate correct values of k for simulating asymmetric compound channel with different side slopes of the internal wall. The first approach is based on Abril and Knight (2004) who suggest fixed values for main channel and floodplain regions. In the second approach, the equations developed by Devi and Khatua (2017) that relate the variation of the secondary flow coefficients with the relative depth ( β) and width ratio ( α) are used. The results indicate that the calibration method developed by Devi and Khatua (2017) is a better choice for calibrating the secondary flow coefficients than using the first approach which assumes a fixed value of k for different flow depths. The results also indicate that the boundary condition based on the shear force continuity can successfully be used for simulating rectangular compound channels, while the continuity of depth-averaged velocity and its gradient is accepted boundary condition in simulations of trapezoidal compound channels. However, the SKM performance for predicting the boundary shear stress over the shear layer region may not be improved by only imposing the suitable calibrated values of secondary flow coefficients. This is because difficulties of modelling the complex interaction that develops between the flows in the main channel and on the floodplain in this region.

A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

PubMed

Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

2017-12-01

Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

Efficient geostatistical inversion of transient groundwater flow using preconditioned nonlinear conjugate gradients

NASA Astrophysics Data System (ADS)

Klein, Ole; Cirpka, Olaf A.; Bastian, Peter; Ippisch, Olaf

2017-04-01

In the geostatistical inverse problem of subsurface hydrology, continuous hydraulic parameter fields, in most cases hydraulic conductivity, are estimated from measurements of dependent variables, such as hydraulic heads, under the assumption that the parameter fields are autocorrelated random space functions. Upon discretization, the continuous fields become large parameter vectors with O (104 -107) elements. While cokriging-like inversion methods have been shown to be efficient for highly resolved parameter fields when the number of measurements is small, they require the calculation of the sensitivity of each measurement with respect to all parameters, which may become prohibitive with large sets of measured data such as those arising from transient groundwater flow. We present a Preconditioned Conjugate Gradient method for the geostatistical inverse problem, in which a single adjoint equation needs to be solved to obtain the gradient of the objective function. Using the autocovariance matrix of the parameters as preconditioning matrix, expensive multiplications with its inverse can be avoided, and the number of iterations is significantly reduced. We use a randomized spectral decomposition of the posterior covariance matrix of the parameters to perform a linearized uncertainty quantification of the parameter estimate. The feasibility of the method is tested by virtual examples of head observations in steady-state and transient groundwater flow. These synthetic tests demonstrate that transient data can reduce both parameter uncertainty and time spent conducting experiments, while the presented methods are able to handle the resulting large number of measurements.

Investigation of the continuous flow of the sample solution on the performance of electromembrane extraction: Comparison with conventional procedure.

PubMed

Nojavan, Saeed; Sirani, Mahsa; Asadi, Sakine

2017-10-01

In this study, electromembrane extraction from a flowing sample solution, termed as continuous-flow electromembrane extraction, was developed and compared with conventional procedures for the determination of four basic drugs in real samples. Experimental parameters affecting the extraction efficiency were further studied and optimized. Under optimum conditions, linearity of continuous-flow procedure was within 8.0-500 ng/mL, while it was wider for conventional procedures (2.0-500 ng/mL). Moreover, repeatability (percentage relative standard deviation) was found to range between 5.6 and 10.4% (n = 3) for the continuous-flow procedure, with a better repeatability than that of conventional procedures (2.3-5.5% (n = 3)). Also, for the continuous-flow procedure, the estimated detection limit (signal-to-noise ratio = 3) was less than 2.4 ng/mL and extraction recoveries were within 8-10%, while the corresponding figures for conventional procedures were less than 0.6 ng/mL and 42-60%, respectively. Thus, the results showed that both continuous flow and conventional procedures were applicable for the extraction of model compounds. However, the conventional procedure was more convenient to use, and thus it was applied to determine sample drugs in real urine and wastewater samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Continued Investigation of Leakage and Power Loss Test Results for Competing Turbine Engine Seals

NASA Technical Reports Server (NTRS)

Delgado, Irebert R.; Proctor, Margaret P.

2007-01-01

Seal leakage decreases with increasing surface speed due to reduced clearances from disk centrifugal growth. Annular and labyrinth seal leakage are 2-3 times greater than brush and finger seal leakage. Seal leakage rates increase with increasing temperature because of seal clearance growth due to different coefficients of thermal expansion between the seal and test disk. Seal power loss is not strongly affected by inlet temperature. Seal power loss increases with increasing surface speed, seal pressure differential, mass flow rate or flow factor, and radial clearance. The brush and finger seals had nearly the same power loss. Annular and labyrinth seal power loss were higher than finger or brush seal power loss. The brush seal power loss was the lowest and 15-30% lower than annular and labyrinth seal power loss.

Efficient Computation of Atmospheric Flows with Tempest: Validation of Next-Generation Climate and Weather Prediction Algorithms at Non-Hydrostatic Scales

NASA Astrophysics Data System (ADS)

Guerra, Jorge; Ullrich, Paul

2016-04-01

Tempest is a next-generation global climate and weather simulation platform designed to allow experimentation with numerical methods for a wide range of spatial resolutions. The atmospheric fluid equations are discretized by continuous / discontinuous finite elements in the horizontal and by a staggered nodal finite element method (SNFEM) in the vertical, coupled with implicit/explicit time integration. At horizontal resolutions below 10km, many important questions remain on optimal techniques for solving the fluid equations. We present results from a suite of idealized test cases to validate the performance of the SNFEM applied in the vertical with an emphasis on flow features and dynamic behavior. Internal gravity wave, mountain wave, convective bubble, and Cartesian baroclinic instability tests will be shown at various vertical orders of accuracy and compared with known results.

A Depth-Averaged 2-D Simulation for Coastal Barrier Breaching Processes

DTIC Science & Technology

2011-05-01

including bed change and variable flow density in the flow continuity and momentum equations. The model adopts the HLL approximate Riemann solver to handle...flow density in the flow continuity and momentum equations. The model adopts the HLL approximate Riemann solver to handle the mixed-regime flows near...18 547 Keulegan equation or the Bernoulli equation, and the breach morphological change is determined using simplified sediment transport models

An investigation of the basic physics of irrigation in urology and the role of automated pump irrigation in cystoscopy.

PubMed

Chang, Dwayne; Manecksha, Rustom P; Syrrakos, Konstantinos; Lawrentschuk, Nathan

2012-01-01

To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS). Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable drip poles, uroflowmetry devices, and model bladders. In Experiment 1, saline bags were elevated to measure the increment in flow rate. In Experiment 2, saline bags were placed under external pressures to evaluate the effect on flow rate. In Experiment 3, flow rate changes in response to variable bladder fullness were measured. Elevating saline bags caused an increase in flow rates, however the increment slowed down beyond a height of 80 cm. Increase in external pressure on saline bags elevated flow rates, but inconsistently. A fuller bladder led to a decrease in flow rates. In all experiments, the AIFPS posted consistent flow rates. Traditional irrigation systems were susceptible to changes in height of irrigation solution, external pressure application, and bladder fullness thus creating inconsistent flow rates. The AIFPS produced consistent flow rates and was not affected by any of the factors investigated in the study.

An approach for the regularization of a power flow solution around the maximum loading point

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kataoka, Y.

1992-08-01

In the conventional power flow solution, the boundary conditions are directly specified by active power and reactive power at each node, so that the singular point coincided with the maximum loading point. For this reason, the computations are often disturbed by ill-condition. This paper proposes a new method for getting the wide-range regularity by giving some modifications to the conventional power flow solution method, thereby eliminating the singular point or shifting it to the region with the voltage lower than that of the maximum loading point. Then, the continuous execution of V-P curves including maximum loading point is realized. Themore » efficiency and effectiveness of the method are tested in practical 598-nodes system in comparison with the conventional method.« less

The walk is never random: subtle landscape effects shape gene flow in a continuous white-tailed deer population in the Midwestern United States

USGS Publications Warehouse

Robinson, Stacie J.; Samuel, Michael D.; Lopez, Davin L.; Shelton, Paul

2012-01-01

One of the pervasive challenges in landscape genetics is detecting gene flow patterns within continuous populations of highly mobile wildlife. Understanding population genetic structure within a continuous population can give insights into social structure, movement across the landscape and contact between populations, which influence ecological interactions, reproductive dynamics or pathogen transmission. We investigated the genetic structure of a large population of deer spanning the area of Wisconsin and Illinois, USA, affected by chronic wasting disease. We combined multiscale investigation, landscape genetic techniques and spatial statistical modelling to address the complex questions of landscape factors influencing population structure. We sampled over 2000 deer and used spatial autocorrelation and a spatial principal components analysis to describe the population genetic structure. We evaluated landscape effects on this pattern using a spatial autoregressive model within a model selection framework to test alternative hypotheses about gene flow. We found high levels of genetic connectivity, with gradients of variation across the large continuous population of white-tailed deer. At the fine scale, spatial clustering of related animals was correlated with the amount and arrangement of forested habitat. At the broader scale, impediments to dispersal were important to shaping genetic connectivity within the population. We found significant barrier effects of individual state and interstate highways and rivers. Our results offer an important understanding of deer biology and movement that will help inform the management of this species in an area where overabundance and disease spread are primary concerns.

Coal Technology Program progress report for April 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

In the Hydrocarbonization Research program, two successful experiments were completed in the bench-scale hydrocarbonizer. A settling test at a lower temperature (390/sup 0/F) using 20 percent toluene in Solvent Refined Coal (SRC) Unfiltered Oil (UFO) produced a 30 percent clarified product in 2 hr. Characterization tests include distillation curves for Wilsonville's SRC-UFO and a particle size distribution of Pittsburg and Midway Coal Mining Company's (PAMCO) SRC-UFO. Studies of intermediate-temperature pyrolysis of large blocks have been maintained with char samples continuing to demonstrate pyrophoricity, even after heating to 700/sup 0/C. Simulated distillation analysis of tars produced by the last eight experimentsmore » are being compared with those performed at Laramie upon tars produced by the Hanna No. 2 experiment. In Coal-Fueled MIUS, stainless steel tubing to be used in one of the furnace tube bundles was ordered and the bid package for the furnace completed. Tests continued on the coal feed system and with the cold flow fluidized bed model. For the Synthoil process, flow diagrams, material balances, and utilities requirements were completed for the entire facility. For the Hydrocarbonization process, flowsheets were reviewed for compatibility; equipment lists were brought up to date; and utilities requirements were compiled from the individual flowsheets. The char recovery and storage subsystem flowsheet was completed. (auth)« less

Efficiency of Artemia cysts removal as a model invasive spore using a continuous microwave system with heat recovery.

PubMed

Balasubramanian, Sundar; Ortego, Jeffrey; Rusch, Kelly A; Boldor, Dorin

2008-12-15

A continuous microwave system to treat ballast water inoculated with Artemia salina cysts as a model invasive spore was tested for its efficacy in inactivating the cysts present. The system was tested at two different flow rates (1 and 2 L x min(-1)) and two different power levels (2.5 and 4.5 kW). Temperature profiles indicate that the system could deliver heating loads in excess of 100 degrees C in a uniform and near-instantaneous manner when using a heat recovery system. Except for a power and flow rate combination of 2.5 kW and 2 L x min(-1), complete inactivation of the cysts was observed at all combinations at holding times below 100 s. The microwave treatment was better or equal to the control treatment in inactivating the cysts. Use of heat exchangers increased the power conversion efficiency and the overall efficiency of the treatment system. Cost economics analysis indicates that in the present form of development microwave treatment costs are higher than the existing ballast water treatment methods. Overall, tests results indicated that microwave treatment of ballast water is a promising method that can be used in conjunction with other methods to form an efficient treatment system that can prevent introduction of potentially invasive spore forming species in non-native waters.

Performance of a pilot-scale continuous flow microbial electrolysis cell fed winery wastewater.

PubMed

Cusick, Roland D; Bryan, Bill; Parker, Denny S; Merrill, Matthew D; Mehanna, Maha; Kiely, Patrick D; Liu, Guangli; Logan, Bruce E

2011-03-01

A pilot-scale (1,000 L) continuous flow microbial electrolysis cell was constructed and tested for current generation and COD removal with winery wastewater. The reactor contained 144 electrode pairs in 24 modules. Enrichment of an exoelectrogenic biofilm required ~60 days, which is longer than typically needed for laboratory reactors. Current generation was enhanced by ensuring adequate organic volatile fatty acid content (VFA/SCOD ≥ 0.5) and by raising the wastewater temperature (31 ± 1°C). Once enriched, SCOD removal (62 ± 20%) was consistent at a hydraulic retention time of 1 day (applied voltage of 0.9 V). Current generation reached a maximum of 7.4 A/m(3) by the planned end of the test (after 100 days). Gas production reached a maximum of 0.19 ± 0.04 L/L/day, although most of the product gas was converted to methane (86 ± 6%). In order to increase hydrogen recovery in future tests, better methods will be needed to isolate hydrogen gas produced at the cathode. These results show that inoculation and enrichment procedures are critical to the initial success of larger-scale systems. Acetate amendments, warmer temperatures, and pH control during startup were found to be critical for proper enrichment of exoelectrogenic biofilms and improved reactor performance.

Results of test MA22 in the NASA/LaRC 31-inch CFHT on an 0.010-scale model (32-0) of the space shuttle configuration 3 to determine RCS jet flow field interaction, volume 1. [wind tunnel tests for interactions of aerodynamic heating on jet flow

NASA Technical Reports Server (NTRS)

Kanipe, D. B.

1976-01-01

A wind tunnel test was conducted in the Langley Research Center 31-inch Continuous Flow Hypersonic Wind Tunnel from May 6, 1975 through June 3, 1975. The primary objectives of this test were the following: (1) to study the ability of the wind tunnel to repeat, on a run-to-run basis, data taken for identical configurations to determine if errors in repeatability could have a significant effect on jet interaction data, (2) to determine the effect of aerodynamic heating of the scale model on jet interaction, (3) to investigate the effects of elevon and body flap deflections on jet interaction, (4) to determine if the effects from jets fired separately along different axes can be added to equal the effects of the jets fired simultaneously (super position effects), (5) to study multiple jet effects, and (6) to investigate area ratio effects, i.e., the effect on jet interaction measurements of using wind tunnel nozzles with different area ratios in the same location. The model used in the test was a .010-scale model of the Space Shuttle Orbiter Configuration 3. The test was conducted at Mach 10.3 and a dynamic pressure of 150 psf. RCS chamber pressure was varied to simulate free flight dynamic pressures of 5, 7.5, 10, and 20 psf.

Evaluation of a Low-Cost Bubble CPAP System Designed for Resource-Limited Settings.

PubMed

Bennett, Desmond J; Carroll, Ryan W; Kacmarek, Robert M

2018-04-01

Respiratory compromise is a leading contributor to global neonatal death. CPAP is a method of treatment that helps maintain lung volume during expiration, promotes comfortable breathing, and improves oxygenation. Bubble CPAP is an effective alternative to standard CPAP. We sought to determine the reliability and functionality of a low-cost bubble CPAP device designed for low-resource settings. The low-cost bubble CPAP device was compared to a commercially available bubble CPAP system. The devices were connected to a lung simulator that simulated neonates of 4 different weights with compromised respiratory mechanics (∼1, ∼3, ∼5, and ∼10 kg). The devices' abilities to establish and maintain pressure and flow under normal conditions as well as under conditions of leak were compared. Multiple combinations of pressure levels (5, 8, and 10 cm H 2 O) and flow levels (3, 6, and 10 L/min) were tested. The endurance of both devices was also tested by running the systems continuously for 8 h and measuring the changes in pressure and flow. Both devices performed equivalently during the no-leak and leak trials. While our testing revealed individual differences that were statistically significant and clinically important (>10% difference) within specific CPAP and flow-level settings, no overall comparisons of CPAP or flow were both statistically significant and clinically important. Each device delivered pressures similar to the desired pressures, although the flows delivered by both machines were lower than the set flows in most trials. During the endurance trials, the low-cost device was marginally better at maintaining pressure, while the commercially available device was better at maintaining flow. The low-cost bubble CPAP device evaluated in this study is comparable to a bubble CPAP system used in developed settings. Extensive clinical trials, however, are necessary to confirm its effectiveness. Copyright © 2018 by Daedalus Enterprises.

Electrohydrodynamic effects in continuous flow electrophoresis

NASA Technical Reports Server (NTRS)

Rhodes, P. H.; Snyder, R. S.; Roberts, G. O.; Baygents, J. C.

1991-01-01

We demonstrate experimentally and theoretically the importance of electrohydrodynamic (EHD) flows in continuous-flow electrophoresis (CFE) separations. These flows are associated with variations in the conductivity or dielectric constant, and are quadratic in the field strength. They appear to be the main cause of extraneous and undesired flows in CFE which have degraded separation performance and have until now not been explained. We discuss the importance of EHD flows relative to other effects. We also describe possible techniques for reducing the associated degradation of CFE separations.

Comparisons of a Three-Dimensional, Full Navier Stokes Computer Model with High Mach Number Combuster Test Data

NASA Technical Reports Server (NTRS)

Watkins, William B.

1990-01-01

Comparisons between scramjet combustor data and a three-dimensional full Navier-Stokes calculation have been made to verify and substantiate computational fluid dynamics (CFD) codes and application procedures. High Mach number scramjet combustor development will rely heavily on CFD applications to provide wind tunnel-equivalent data of quality sufficient to design, build and fly hypersonic aircraft. Therefore. detailed comparisons between CFD results and test data are imperative. An experimental case is presented, for which combustor wall static pressures were measured and flow-fieid interferograms were obtained. A computer model was done of the experiment, and counterpart parameters are compared with experiment. The experiment involved a subscale combustor designed and fabricated for the National Aero-Space Plane Program, and tested in the Calspan Corporation 96" hypersonic shock tunnel. The combustor inlet ramp was inclined at a 20 angle to the shock tunnel nozzle axis, and resulting combustor entrance flow conditions simulated freestream M=10. The combustor body and cowl walls were instrumented with static pressure transducers, and the combustor lateral walls contained windows through which flowfield holographic interferograms were obtained. The CFD calculation involved a three-dimensional time-averaged full Navier-Stokes code applied to the axial flow segment containing fuel injection and combustion. The full Navier-Stokes approach allowed for mixed supersonic and subsonic flow, downstream-upstream communication in subsonic flow regions, and effects of adverse pressure gradients. The code included hydrogen-air chemistry in the combustor segment which begins near fuel injection and continues through combustor exhaust. Combustor ramp and inlet segments on the combustor lateral centerline were modelled as two dimensional. Comparisons to be shown include calculated versus measured wall static pressures as functions of axial flow coordinate, and calculated path-averaged density contours versus an holographic Interferogram.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shamsuddin Ilias

Fouling problems are perhaps the single most important reason for relatively slow acceptance of ultrafiltration in many areas of chemical and biological processing. To overcome the losses in permeate flux associated with concentration polarization and fouling in cross flow membrane filtration, we investigated the concept of flow reversal as a method to enhance membrane flux in ultrafiltration. Conceptually, flow reversal prevents the formation of stable hydrodynamic and concentration boundary layers at or near the membrane surface. Further more, periodic reversal of the flow direction of the feed stream at the membrane surface results in prevention and mitigation of membrane fouling.more » Consequently, these advantages are expected to enhance membrane flux significantly. A crossflow membrane filtration unit was designed and built to test the concept of periodic flow reversal for flux enhancement. The essential elements of the system include a crossflow hollow fiber membrane module integrated with a two-way valve to direct the feed flow directions. The two-way valve is controlled by a controller-timer for periodic reversal of flow of feed stream. Another important feature of the system is that with changing feed flow direction, the permeate flow direction is also changed to maintain countercurrent feed and permeate flows for enhanced mass transfer driving force (concentration difference). In our previous report, we reported our work on UF of BSA. In this report, we report our continuing application of Flow Reversal technique in clarification of apple juice containing pectin. The presence of pectin in apple juice makes the clarification process difficult and is believed to cause membrane fouling. Of all compounds found in apple juice, pectin is most often identified as the major hindrance to filtration performance. Laboratory-scale tests on a hollow-fiber ultrafiltration membrane module using pectin in apple juice as feed show that under flow reversal conditions, the permeate flux is significantly enhanced when compared with the conventional unidirectional flow.« less

The design and fabrication of two portal vein flow phantoms by different methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yunker, Bryan E., E-mail: bryan.yunker@ucdenver.edu; Lanning, Craig J.; Shandas, Robin

2014-02-15

Purpose: This study outlines the design and fabrication techniques for two portal vein flow phantoms. Methods: A materials study was performed as a precursor to this phantom fabrication effort and the desired material properties are restated for continuity. A three-dimensional portal vein pattern was created from the Visual Human database. The portal vein pattern was used to fabricate two flow phantoms by different methods with identical interior surface geometry using computer aided design software tools and rapid prototyping techniques. One portal flow phantom was fabricated within a solid block of clear silicone for use on a table with Ultrasound ormore » within medical imaging systems such as MRI, CT, PET, or SPECT. The other portal flow phantom was fabricated as a thin walled tubular latex structure for use in water tanks with Ultrasound imaging. Both phantoms were evaluated for usability and durability. Results: Both phantoms were fabricated successfully and passed durability criteria for flow testing in the next project phase. Conclusions: The fabrication methods and materials employed for the study yielded durable portal vein phantoms.« less

Effects of episodic sediment supply on bedload transport rate in mountain rivers. Detecting debris flow activity using continuous monitoring

NASA Astrophysics Data System (ADS)

Uchida, Taro; Sakurai, Wataru; Iuchi, Takuma; Izumiyama, Hiroaki; Borgatti, Lisa; Marcato, Gianluca; Pasuto, Alessandro

2018-04-01

Monitoring of sediment transport from hillslopes to channel networks as a consequence of floods with suspended and bedload transport, hyperconcentrated flows, debris and mud flows is essential not only for scientific issues, but also for prevention and mitigation of natural disasters, i.e. for hazard assessment, land use planning and design of torrent control interventions. In steep, potentially unstable terrains, ground-based continuous monitoring of hillslope and hydrological processes is still highly localized and expensive, especially in terms of manpower. In recent years, new seismic and acoustic methods have been developed for continuous bedload monitoring in mountain rivers. Since downstream bedload transport rate is controlled by upstream sediment supply from tributary channels and bed-external sources, continuous bedload monitoring might be an effective tool for detecting the sediments mobilized by debris flow processes in the upper catchment and thus represent an indirect method to monitor slope instability processes at the catchment scale. However, there is poor information about the effects of episodic sediment supply from upstream bed-external sources on downstream bedload transport rate at a single flood time scale. We have examined the effects of sediment supply due to upstream debris flow events on downstream bedload transport rate along the Yotagiri River, central Japan. To do this, we have conducted continuous bedload observations using a hydrophone (Japanese pipe microphone) located 6.4 km downstream the lower end of a tributary affected by debris flows. Two debris flows occurred during the two-years-long observation period. As expected, bedload transport rate for a given flow depth showed to be larger after storms triggering debris flows. That is, although the magnitude of sediment supply from debris flows is not large, their effect on bedload is propagating >6 km downstream at a single flood time scale. This indicates that continuous bedload observations could be effective for detecting sediment supply as a consequence of debris flow events.

A continuous-flow capillary mixing method to monitor reactions on the microsecond time scale.

PubMed Central

Shastry, M C; Luck, S D; Roder, H

1998-01-01

A continuous-flow capillary mixing apparatus, based on the original design of Regenfuss et al. (Regenfuss, P., R. M. Clegg, M. J. Fulwyler, F. J. Barrantes, and T. M. Jovin. 1985. Rev. Sci. Instrum. 56:283-290), has been developed with significant advances in mixer design, detection method and data analysis. To overcome the problems associated with the free-flowing jet used for observation in the original design (instability, optical artifacts due to scattering, poor definition of the geometry), the solution emerging from the capillary is injected directly into a flow-cell joined to the tip of the outer capillary via a ground-glass joint. The reaction kinetics are followed by measuring fluorescence versus distance downstream from the mixer, using an Hg(Xe) arc lamp for excitation and a digital camera with a UV-sensitized CCD detector for detection. Test reactions involving fluorescent dyes indicate that mixing is completed within 15 micros of its initiation and that the dead time of the measurement is 45 +/- 5 micros, which represents a >30-fold improvement in time resolution over conventional stopped-flow instruments. The high sensitivity and linearity of the CCD camera have been instrumental in obtaining artifact-free kinetic data over the time window from approximately 45 micros to a few milliseconds with signal-to-noise levels comparable to those of conventional methods. The scope of the method is discussed and illustrated with an example of a protein folding reaction. PMID:9591695

Small-volume, ultrahigh-vacuum-compatible high-pressure reaction cell for combined kinetic and in situ IR spectroscopic measurements on planar model catalysts

NASA Astrophysics Data System (ADS)

Zhao, Z.; Diemant, T.; Häring, T.; Rauscher, H.; Behm, R. J.

2005-12-01

We describe the design and performance of a high-pressure reaction cell for simultaneous kinetic and in situ infrared reflection (IR) spectroscopic measurements on model catalysts at elevated pressures, between 10-3 and 103mbars, which can be operated both as batch reactor and as flow reactor with defined gas flow. The cell is attached to an ultrahigh-vacuum (UHV) system, which is used for sample preparation and also contains facilities for sample characterization. Specific for this design is the combination of a small cell volume, which allows kinetic measurements with high sensitivity under batch or continuous flow conditions, the complete isolation of the cell from the UHV part during UHV measurements, continuous temperature control during both UHV and high-pressure operation, and rapid transfer between UHV and high-pressure stage. Gas dosing is performed by a designed gas-handling system, which allows operation as flow reactor with calibrated gas flows at adjustable pressures. To study the kinetics of reactions on the model catalysts, a quadrupole mass spectrometer is connected to the high-pressure cell. IR measurements are possible in situ by polarization-modulation infrared reflection-absorption spectroscopy, which also allows measurements at elevated pressures. The performance of the setup is demonstrated by test measurements on the kinetics for CO oxidation and the CO adsorption on a Au /TiO2/Ru(0001) model catalyst film at 1-50 mbar total pressure.

Sequential continuous flow processes for the oxidation of amines and azides by using HOF·MeCN.

PubMed

McPake, Christopher B; Murray, Christopher B; Sandford, Graham

2012-02-13

The generation and use of the highly potent oxidising agent HOF·MeCN in a controlled single continuous flow process is described. Oxidations of amines and azides to corresponding nitrated systems by using fluorine gas, water and acetonitrile by sequential gas-liquid/liquid-liquid continuous flow procedures are reported. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Centrifugal fans: Similarity, scaling laws, and fan performance

NASA Astrophysics Data System (ADS)

Sardar, Asad Mohammad

Centrifugal fans are rotodynamic machines used for moving air continuously against moderate pressures through ventilation and air conditioning systems. There are five major topics presented in this thesis: (1) analysis of the fan scaling laws and consequences of dynamic similarity on modelling; (2) detailed flow visualization studies (in water) covering the flow path starting at the fan blade exit to the evaporator core of an actual HVAC fan scroll-diffuser module; (3) mean velocity and turbulence intensity measurements (flow field studies) at the inlet and outlet of large scale blower; (4) fan installation effects on overall fan performance and evaluation of fan testing methods; (5) two point coherence and spectral measurements conducted on an actual HVAC fan module for flow structure identification of possible aeroacoustic noise sources. A major objective of the study was to identity flow structures within the HVAC module that are responsible for noise and in particular "rumble noise" generation. Possible mechanisms for the generation of flow induced noise in the automotive HVAC fan module are also investigated. It is demonstrated that different modes of HVAC operation represent very different internal flow characteristics. This has implications on both fan HVAC airflow performance and noise characteristics. It is demonstrated from principles of complete dynamic similarity that fan scaling laws require that Reynolds, number matching is a necessary condition for developing scale model fans or fan test facilities. The physical basis for the fan scaling laws derived was established from both pure dimensional analysis and also from the fundamental equations of fluid motion. Fan performance was measured in a three times scale model (large scale blower) in air of an actual forward curved automotive HVAC blower. Different fan testing methods (based on AMCA fan test codes) were compared on the basis of static pressure measurements. Also, the flow through an actual HVAC fan-impeller/diffuser section in water was observed with a flow visualization technique using a shear-thickening dye (in addition to a conventional dye). Full dynamic similarity was maintained between RVAC operation in water as when operated in air. Recommendations are provided both for further investigation of critical flow regions with more sophisticated measurement methods and for improved fan-scroll design to reduce possible aeroacoustic noise with improved aerodynamic performance.

Environmental Assessment of the Hawaii Geothermal Project Well Flow Test Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1976-11-01

The Hawaii Geothermal Project, a coordinated research effort of the University of Hawaii, funded by the County and State of Hawaii, and ERDA, was initiated in 1973 in an effort to identify, generate, and use geothermal energy on the Big Island of Hawaii. A number of stages are involved in developing geothermal power resources: exploration, test drilling, production testing, field development, power plant and powerline construction, and full-scale production. Phase I of the Project, which began in the summer of 1973, involved conducting exploratory surveys, developing analytical models for interpretation of geophysical results, conducting studies on energy recovery from hotmore » brine, and examining the legal and economic implications of developing geothermal resources in the state. Phase II of the Project, initiated in the summer of 1975, centers on drilling an exploratory research well on the Island of Hawaii, but also continues operational support for the geophysical, engineering, and socioeconomic activities delineated above. The project to date is between the test drilling and production testing phase. The purpose of this assessment is to describe the activities and potential impacts associated with extensive well flow testing to be completed during Phase II.« less

Hot-Fire Testing of 5N and 22N HPGP Thrusters

NASA Technical Reports Server (NTRS)

Burnside, Christopher G.; Pedersen, Kevin W.; Pierce, Charles W.

2015-01-01

This hot-fire test continues NASA investigation of green propellant technologies for future missions. To show the potential for green propellants to replace some hydrazine systems in future spacecraft, NASA Marshall Space Flight Center (MSFC) is continuing to embark on hot-fire test campaigns with various green propellant blends.NASA completed hot-fire testing of 5N and 22N HPGP thrusters at the Marshall Space Flight Center’s Component Development Area altitude test stand in April 2015. Both thrusters are ground test articles and not flight ready units, but are representative of potential flight hardware with a known path towards flight application. The purpose of the 5N testing was to perform facility check-outs and generate a small set of data for comparison to ECAPS and Orbital ATK data sets. The 5N thruster performed as expected with thrust and propellant flow-rate data generated that are similar to previous testing at Orbital ATK. Immediately following the 5N testing, and using the same facility, the 22N testing was conducted on the same test stand with the purpose of demonstrating the 22N performance. The results of 22N testing indicate it performed as expected.The results of the hot-fire testing are presented in this paper and presentation.

Shuttle Wastewater Solution Characterization

NASA Technical Reports Server (NTRS)

Adam, Niklas; Pham, Chau

2011-01-01

During the 31st shuttle mission to the International Space Station, STS-129, there was a clogging event in the shuttle wastewater tank. A routine wastewater dump was performed during the mission and before the dump was completed, degraded flow was observed. In order to complete the wastewater dump, flow had to be rerouted around the dump filter. As a result, a basic chemical and microbial investigation was performed to understand the shuttle wastewater system and perform mitigation tasks to prevent another blockage. Testing continued on the remaining shuttle flights wastewater and wastewater tank cleaning solutions. The results of the analyses and the effect of the mitigation steps are detailed in this paper.

Modeling Turbulent Combustion for Variable Prandtl and Schmidt Number

NASA Technical Reports Server (NTRS)

Hassan, H. A.

2004-01-01

This report consists of two abstracts submitted for possible presentation at the AIAA Aerospace Science Meeting to be held in January 2005. Since the submittal of these abstracts we are continuing refinement of the model coefficients derived for the case of a variable Turbulent Prandtl number. The test cases being investigated are a Mach 9.2 flow over a degree ramp and a Mach 8.2 3-D calculation of crossing shocks. We have developed an axisymmetric code for treating axisymmetric flows. In addition the variable Schmidt number formulation was incorporated in the code and we are in the process of determining the model constants.

Low-Flow Characteristics and Regionalization of Low-Flow Characteristics for Selected Streams in Arkansas

USGS Publications Warehouse

Funkhouser, Jaysson E.; Eng, Ken; Moix, Matthew W.

2008-01-01

Water use in Arkansas has increased dramatically in recent years. Since 1990, the use of water for all purposes except power generation has increased 53 percent (4,004 cubic feet per second in 1990 to 6,113 cubic feet per second in 2005). The biggest users are agriculture (90 percent), municipal water supply (4 percent) and industrial supply (2 percent). As the population of the State continues to grow, so does the demand for the State's water resources. The low-flow characteristics of a stream ultimately affect its utilization by humans. Specific information on the low-flow characteristics of streams is essential to State water-management agencies such as the Arkansas Department of Environmental Quality, the Arkansas Natural Resources Commission, and the Arkansas Game and Fish Commission when dealing with problems related to irrigation, municipal and industrial water supplies, fish and wildlife conservation, and dilution of waste. Low-flow frequency data are of particular value to management agencies responsible for the development and management of the State's water resources. This report contains the low-flow characteristics for 70 active continuous-streamflow record gaging stations, 59 inactive continuous-streamflow record stations, and 101 partial-record gaging stations. These characteristics are the annual 7-day, 10-year low flow and the annual 7-day, 2-year low flow, and the seasonal, bimonthly, and monthly 7-day, 10-year low flow for the 129 active and inactive continuous-streamflow record and 101 partial-record gaging stations. Low-flow characteristics were computed on the basis of streamflow data for the period of record through September 2005 for the continuous-streamflow record and partial-record streamflow gaging stations. The low-flow characteristics of these continuous- and partial-record streamflow gaging stations were utilized in a regional regression analysis to produce equations for estimating the annual, seasonal, bimonthly, and monthly (November through April) 7-day, 10-year low flows and the annual 7-day, 2-year low flow for ungaged streams in the western two-thirds of Arkansas.

Advanced thermal energy management: A thermal test bed and heat pipe simulation

NASA Technical Reports Server (NTRS)

Barile, Ronald G.

1986-01-01

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Using a tracer technique to identify the extent of non-ideal flows in the continuous mixing of non-Newtonian fluids

NASA Astrophysics Data System (ADS)

Patel, D.; Ein-Mozaffari, F.; Mehrvar, M.

2013-05-01

The identification of non-ideal flows in a continuous-flow mixing of non-Newtonian fluids is a challenging task for various chemical industries: plastic manufacturing, water and wastewater treatment, and pulp and paper manufacturing. Non-ideal flows such as channelling, recirculation, and dead zones significantly affect the performance of continuous-flow mixing systems. Therefore, the main objective of this paper was to develop an identification protocol to measure non-ideal flows in the continuous-flow mixing system. The extent of non-ideal flows was quantified using a dynamic model that incorporated channelling, recirculation, and dead volume in the mixing vessel. To estimate the dynamic model parameters, the system was excited using a frequency-modulated random binary input by injecting the saline solution (as a tracer) into the fresh feed stream prior to being pumped into the mixing vessel. The injection of the tracer was controlled by a computer-controlled on-off solenoid valve. Using the trace technique, the extent of channelling and the effective mixed volume were successfully determined and used as mixing quality criteria. Such identification procedures can be applied at various areas of chemical engineering in order to improve the mixing quality.

Utilization of Stop-flow Micro-tubing Reactors for the Development of Organic Transformations.

PubMed

Toh, Ren Wei; Li, Jie Sheng; Wu, Jie

2018-01-04

A new reaction screening technology for organic synthesis was recently demonstrated by combining elements from both continuous micro-flow and conventional batch reactors, coined stop-flow micro-tubing (SFMT) reactors. In SFMT, chemical reactions that require high pressure can be screened in parallel through a safer and convenient way. Cross-contamination, which is a common problem in reaction screening for continuous flow reactors, is avoided in SFMT. Moreover, the commercially available light-permeable micro-tubing can be incorporated into SFMT, serving as an excellent choice for light-mediated reactions due to a more effective uniform light exposure, compared to batch reactors. Overall, the SFMT reactor system is similar to continuous flow reactors and more superior than batch reactors for reactions that incorporate gas reagents and/or require light-illumination, which enables a simple but highly efficient reaction screening system. Furthermore, any successfully developed reaction in the SFMT reactor system can be conveniently translated to continuous-flow synthesis for large scale production.

Mathematical models of continuous flow electrophoresis: Electrophoresis technology

NASA Technical Reports Server (NTRS)

Saville, Dudley A.

1986-01-01

Two aspects of continuous flow electrophoresis were studied: (1) the structure of the flow field in continuous flow devices; and (2) the electrokinetic properties of suspended particles relevant to electrophoretic separations. Mathematical models were developed to describe flow structure and stability, with particular emphasis on effects due to buoyancy. To describe the fractionation of an arbitrary particulate sample by continuous flow electrophoresis, a general mathematical model was constructed. In this model, chamber dimensions, field strength, buffer composition, and other design variables can be altered at will to study their effects on resolution and throughput. All these mathematical models were implemented on a digital computer and the codes are available for general use. Experimental and theoretical work with particulate samples probed how particle mobility is related to buffer composition. It was found that ions on the surface of small particles are mobile, contrary to the widely accepted view. This influences particle mobility and suspension conductivity. A novel technique was used to measure the mobility of particles in concentrated suspensions.

Anomalous transport in fracture networks: field scale experiments and modelling

NASA Astrophysics Data System (ADS)

Kang, P. K.; Le Borgne, T.; Bour, O.; Dentz, M.; Juanes, R.

2012-12-01

Anomalous transport is widely observed in different settings and scales of transport through porous and fractured geologic media. A common signature of anomalous transport is the late-time power law tailing in breakthrough curves (BTCs) during tracer tests. Various conceptual models of anomalous transport have been proposed, including multirate mass transfer, continuous time random walk, and stream tube models. Since different conceptual models can produce equally good fits to a single BTC, tracer test interpretation has been plagued with ambiguity. Here, we propose to resolve such ambiguity by analyzing BTCs obtained from both convergent and push-pull flow configurations at two different fracture planes. We conducted field tracer tests in a fractured granite formation close to Ploemeur, France. We observe that BTC tailing depends on the flow configuration and the injection fracture. Specifically the tailing disappears under push-pull geometry, and when we injected at a fracture with high flux (Figure 1). This indicates that for this fractured granite, BTC tailing is controlled by heterogeneous advection and not by matrix diffusion. To explain the change in tailing behavior for different flow configurations, we employ a simple lattice network model with heterogeneous conductivity distribution. The model assigns random conductivities to the fractures and solves the Darcy equation for an incompressible fluid, enforcing mass conservation at fracture intersections. The mass conservation constraint yields a correlated random flow through the fracture system. We investigate whether BTC tailing can be explained by the spatial distribution of preferential flow paths and stagnation zones, which is controlled by the conductivity variance and correlation length. By combining the results from the field tests and numerical modeling, we show that the reversibility of spreading is a key mechanism that needs to be captured. We also demonstrate the dominant role of the injection fracture on the tailing behavior: where we inject makes the difference in the tailing. Blue line is a BTC with injection into a slow velocity zone under convergent flow configuration. The late-time tailing observed for the convergent test diminished for push-pull experiment performed in the same zone(red line). Black line is a BTC with injection into a high velocity zone under convergent flow configuration. Insets: illustration of convergent and push-pull tracer tests using a double packer system.

Design and verification of a turbofan swirl augmentor

NASA Technical Reports Server (NTRS)

Egan, W. J., Jr.; Shadowen, J. H.

1978-01-01

The paper discusses the details of the design and verification testing of a full-scale turbofan 'swirl' augmentor at sea level and altitude. No flameholders are required in the swirl augmentor since the radial motion of the hot pilot gases and subsequent combustion products provides a continuous ignition front across the stream. Results of rig testing of this full-scale swirl augmentor on an F100 engine, which are very encouraging, and future development plans are presented. The results validate the application of the centrifugal-force swirling flow concept to a turbofan augmentor.

Cerebral oxygenation in the beach chair position for shoulder surgery in regional anesthesia: impact on cerebral blood flow and neurobehavioral outcome.

PubMed

Aguirre, José A; Märzendorfer, Olivia; Brada, Muriel; Saporito, Andrea; Borgeat, Alain; Bühler, Philipp

2016-12-01

Beach chair position is considered a potential risk factor for central neurological events particularly if combined with low blood pressure. The aim of this study was to assess the impact of regional anesthesia on cerebral blood flow and neurobehavioral outcome. This is a prospective, assessor-blinded observational study evaluating patients in the beach chair position undergoing shoulder surgery under regional anesthesia. University hospital operating room. Forty patients with American Society of Anesthesiologists classes I-II physical status scheduled for elective shoulder surgery. Cerebral saturation and blood flow of the middle cerebral artery were measured prior to anesthesia and continued after beach chair positioning until discharge to the postanesthesia care unit. The anesthesiologist was blinded for these values. Controlled hypotension with systolic blood pressure≤100mm Hg was maintained during surgery. Neurobehavioral tests and values of regional cerebral saturation, bispectral index, the mean maximal blood flow of the middle cerebral artery, and invasive blood pressure were measured prior to regional anesthesia, and measurements were repeated after placement of the patient on the beach chair position and every 20 minutes thereafter until discharge to postanesthesia care unit. The neurobehavioral tests were repeated the day after surgery. The incidence of cerebral desaturation events was 5%. All patients had a significant blood pressure drop 5 minutes after beach chair positioning, measured at the heart as well as the acoustic meatus levels, when compared with baseline values (P<.05). There was no decrease in either the regional cerebral saturation (P=.136) or the maximal blood flow of the middle cerebral artery (P=.212) at the same time points. Some neurocognitive tests showed an impairment 24 hours after surgery (P<.001 for 2 of 3 tests). Beach chair position in patients undergoing regional anesthesia for shoulder surgery had no major impact on cerebral blood flow and cerebral oxygenation. However, some impact on neurobehavioral outcome 24 hours after surgery was observed. Copyright © 2016 Elsevier Inc. All rights reserved.

Seeking excellence: An evaluation of 235 international laboratories conducting water isotope analyses by isotope-ratio and laser-absorption spectrometry.

PubMed

Wassenaar, L I; Terzer-Wassmuth, S; Douence, C; Araguas-Araguas, L; Aggarwal, P K; Coplen, T B

2018-03-15

Water stable isotope ratios (δ 2 H and δ 18 O values) are widely used tracers in environmental studies; hence, accurate and precise assays are required for providing sound scientific information. We tested the analytical performance of 235 international laboratories conducting water isotope analyses using dual-inlet and continuous-flow isotope ratio mass spectrometers and laser spectrometers through a water isotope inter-comparison test. Eight test water samples were distributed by the IAEA to international stable isotope laboratories. These consisted of a core set of five samples spanning the common δ-range of natural waters, and three optional samples (highly depleted, enriched, and saline). The fifth core sample contained unrevealed trace methanol to assess analyst vigilance to the impact of organic contamination on water isotopic measurements made by all instrument technologies. For the core and optional samples ~73 % of laboratories gave acceptable results within 0.2 ‰ and 1.5 ‰ of the reference values for δ 18 O and δ 2 H, respectively; ~27 % produced unacceptable results. Top performance for δ 18 O values was dominated by dual-inlet IRMS laboratories; top performance for δ 2 H values was led by laser spectrometer laboratories. Continuous-flow instruments yielded comparatively intermediate results. Trace methanol contamination of water resulted in extreme outlier δ-values for laser instruments, but also affected reactor-based continuous-flow IRMS systems; however, dual-inlet IRMS δ-values were unaffected. Analysis of the laboratory results and their metadata suggested inaccurate or imprecise performance stemmed mainly from skill- and knowledge-based errors including: calculation mistakes, inappropriate or compromised laboratory calibration standards, poorly performing instrumentation, lack of vigilance to contamination, or inattention to unreasonable isotopic outcomes. To counteract common errors, we recommend that laboratories include 1-2 'known' control standards in all autoruns; laser laboratories should screen each autorun for spectral contamination; and all laboratories should evaluate whether derived d-excess values are realistic when both isotope ratios are measured. Combined, these data evaluation strategies should immediately inform the laboratory about fundamental mistakes or compromised samples. Copyright © 2018 John Wiley & Sons, Ltd.

Seeking excellence: An evaluation of 235 international laboratories conducting water isotope analyses by isotope-ratio and laser-absorption spectrometry

USGS Publications Warehouse

Wassenaar, L. I.; Terzer-Wassmuth, S.; Douence, C.; Araguas-Araguas, L.; Aggarwal, P. K.; Coplen, Tyler B.

2018-01-01

RationaleWater stable isotope ratios (δ2H and δ18O values) are widely used tracers in environmental studies; hence, accurate and precise assays are required for providing sound scientific information. We tested the analytical performance of 235 international laboratories conducting water isotope analyses using dual-inlet and continuous-flow isotope ratio mass spectrometers and laser spectrometers through a water isotope inter-comparison test.MethodsEight test water samples were distributed by the IAEA to international stable isotope laboratories. These consisted of a core set of five samples spanning the common δ-range of natural waters, and three optional samples (highly depleted, enriched, and saline). The fifth core sample contained unrevealed trace methanol to assess analyst vigilance to the impact of organic contamination on water isotopic measurements made by all instrument technologies.ResultsFor the core and optional samples ~73 % of laboratories gave acceptable results within 0.2 ‰ and 1.5 ‰ of the reference values for δ18O and δ2H, respectively; ~27 % produced unacceptable results. Top performance for δ18O values was dominated by dual-inlet IRMS laboratories; top performance for δ2H values was led by laser spectrometer laboratories. Continuous-flow instruments yielded comparatively intermediate results. Trace methanol contamination of water resulted in extreme outlier δ-values for laser instruments, but also affected reactor-based continuous-flow IRMS systems; however, dual-inlet IRMS δ-values were unaffected.ConclusionsAnalysis of the laboratory results and their metadata suggested inaccurate or imprecise performance stemmed mainly from skill- and knowledge-based errors including: calculation mistakes, inappropriate or compromised laboratory calibration standards, poorly performing instrumentation, lack of vigilance to contamination, or inattention to unreasonable isotopic outcomes. To counteract common errors, we recommend that laboratories include 1–2 'known' control standards in all autoruns; laser laboratories should screen each autorun for spectral contamination; and all laboratories should evaluate whether derived d-excess values are realistic when both isotope ratios are measured. Combined, these data evaluation strategies should immediately inform the laboratory about fundamental mistakes or compromised samples.

Photo-induced chemiluminometric determination of Karbutilate in a continuous-flow multicommutation assembly.

PubMed

Amorim, C M P G; Albert-García, J R; Montenegro, M C B S; Araújo, A N; Calatayud, J Martínez

2007-01-17

The present paper deals with the chemiluminescent determination of the herbicide Karbutilate on the basis of its previous photodegradation by using a low-pressure Hg lamp as UV source in a continuous-flow multicommutation assembly (a solenoid valves set). The pesticide solution was segmented by a solenoid valve and sequentially alternated with segments of the 0.001 mol l(-1) of NaOH solution, the suitable media for the formation of photo-fragments; then it passes through the photo-reactor and was lead to the flow-cell after being divided in small segments which were sequentially alternated with the oxidizing system; 2 x 10(-5) mol l(-1) of potassium permanganate in 0.2% pyrophosphoric acid. The studied calibration range, from 0.1 microg l(-1) to 65 mg l(-1), resulted in a linear behaviour over the range 20 microg l(-1)-20 mg l(-1) and fitting the linear equation: I=(1180+/-30)C+(15+/-5) with the correlation coefficient 0.9998. The limit of detection was 10 microg l(-1) and the sample throughput 17 h(-1). After testing the influence of a large series of potential interfering species, the method was applied to water and human urine samples.

Wavenumber-extended high-order oscillation control finite volume schemes for multi-dimensional aeroacoustic computations

NASA Astrophysics Data System (ADS)

Kim, Sungtae; Lee, Soogab; Kim, Kyu Hong

2008-04-01

A new numerical method toward accurate and efficient aeroacoustic computations of multi-dimensional compressible flows has been developed. The core idea of the developed scheme is to unite the advantages of the wavenumber-extended optimized scheme and M-AUSMPW+/MLP schemes by predicting a physical distribution of flow variables more accurately in multi-space dimensions. The wavenumber-extended optimization procedure for the finite volume approach based on the conservative requirement is newly proposed for accuracy enhancement, which is required to capture the acoustic portion of the solution in the smooth region. Furthermore, the new distinguishing mechanism which is based on the Gibbs phenomenon in discontinuity, between continuous and discontinuous regions is introduced to eliminate the excessive numerical dissipation in the continuous region by the restricted application of MLP according to the decision of the distinguishing function. To investigate the effectiveness of the developed method, a sequence of benchmark simulations such as spherical wave propagation, nonlinear wave propagation, shock tube problem and vortex preservation test problem are executed. Also, throughout more realistic shock-vortex interaction and muzzle blast flow problems, the utility of the new method for aeroacoustic applications is verified by comparing with the previous numerical or experimental results.

Low-flow-frequency characteristics for continuous-record streamflow stations in Minnesota

USGS Publications Warehouse

Arntson, A.D.; Lorenz, D.L.

1987-01-01

Annual and summer (May 1 to September 30) low-flow frequency curves are presented for 175 continuous-record streamflow stations in Minnesota. The curves were developed for all stations with 10 or more years of continuous record. The 1-, 7-, and 30-day low-flow discharges at selected recurrence intervals obtained from these curves are listed. Low-flow characteristics can and will vary for a station depending upon the number of years of record and the period gaged. When comparing low-flow characteristics between two or more stations, it should be remembered that no provisions were made to use concurrent periods of record for stations along the same stream.

Dynamically consistent parameterization of mesoscale eddies. Part III: Deterministic approach

NASA Astrophysics Data System (ADS)

Berloff, Pavel

2018-07-01

This work continues development of dynamically consistent parameterizations for representing mesoscale eddy effects in non-eddy-resolving and eddy-permitting ocean circulation models and focuses on the classical double-gyre problem, in which the main dynamic eddy effects maintain eastward jet extension of the western boundary currents and its adjacent recirculation zones via eddy backscatter mechanism. Despite its fundamental importance, this mechanism remains poorly understood, and in this paper we, first, study it and, then, propose and test its novel parameterization. We start by decomposing the reference eddy-resolving flow solution into the large-scale and eddy components defined by spatial filtering, rather than by the Reynolds decomposition. Next, we find that the eastward jet and its recirculations are robustly present not only in the large-scale flow itself, but also in the rectified time-mean eddies, and in the transient rectified eddy component, which consists of highly anisotropic ribbons of the opposite-sign potential vorticity anomalies straddling the instantaneous eastward jet core and being responsible for its continuous amplification. The transient rectified component is separated from the flow by a novel remapping method. We hypothesize that the above three components of the eastward jet are ultimately driven by the small-scale transient eddy forcing via the eddy backscatter mechanism, rather than by the mean eddy forcing and large-scale nonlinearities. We verify this hypothesis by progressively turning down the backscatter and observing the induced flow anomalies. The backscatter analysis leads us to formulating the key eddy parameterization hypothesis: in an eddy-permitting model at least partially resolved eddy backscatter can be significantly amplified to improve the flow solution. Such amplification is a simple and novel eddy parameterization framework implemented here in terms of local, deterministic flow roughening controlled by single parameter. We test the parameterization skills in an hierarchy of non-eddy-resolving and eddy-permitting modifications of the original model and demonstrate, that indeed it can be highly efficient for restoring the eastward jet extension and its adjacent recirculation zones. The new deterministic parameterization framework not only combines remarkable simplicity with good performance but also is dynamically transparent, therefore, it provides a powerful alternative to the common eddy diffusion and emerging stochastic parameterizations.

Analysis of heterogeneous hydrological properties of a mountainous hillslope using intensive water flow measurements

NASA Astrophysics Data System (ADS)

Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Mizuyama, Takahisa; Tsutsumi, Daizo

2013-04-01

Heterogeneous hydrological properties in a foot slope area of mountainous hillslopes should be assessed to understand hydrological phenomena and their effects on discharge and sediment transport. In this study, we analyzed the high-resolution and three-dimensional water movement data to clarify the hydrological process, including heterogeneous phenomena, in detail. We continuously monitored the soil matric pressure head, psi, using 111 tensiometers installed at grid intervals of approximately 1 meter within the soil mantle at the study hillslope. Under a no-rainfall condition, the existence of perennial groundwater seepage flow was detected by exfiltration flux and temporal psi waveforms, which showed delayed responses, only to heavy storm events, and gradual recession limbs. The seepage water spread in the downslope direction and supplied water constantly to the lower section of the slope. At some points in the center of the slope, a perched saturated area was detected in the middle of soil layer, while psi exhibited negative values above the bedrock surface. These phenomena could be inferred partly from the bedrock topography and the distribution of soil hydraulic conductivity assumed from the result of penetration test. At the peak of a rainfall event, on the other hand, continuous high pressure zones (i.e., psi > 50 cmH2O) were generated in the right and left sections of the slope. Both of these high pressure zones converged at the lower region, showing a sharp psi spike up to 100 cmH2O. Along the high pressure zones, flux vectors showed large values and water exfiltration, indicating the occurrence of preferential flow. Moreover, the preferential flow occurred within the area beneath the perched water, indicating the existence of a weathered bedrock layer. This layer had low permeability, which prevented the vertical infiltration of water in the upper part of the layer, but had high permeability as a result of the fractures distributed heterogeneously inside the layer. These fractures acted as a preferential flow channel and flushed the water derived from lateral flow accumulated from the upslope area during the rainfall event. These phenomena occurring at the peak of rainfall event could not be inferred from the parameters derived from the penetration test.

High-flow nasal prong oxygen therapy or nasopharyngeal continuous positive airway pressure for children with moderate-to-severe respiratory distress?*.

PubMed

ten Brink, Fia; Duke, Trevor; Evans, Janine

2013-09-01

The aim of this study was to compare the use of high-flow nasal prong oxygen therapy to nasopharyngeal continuous positive airway pressure in a PICU at a tertiary hospital; to understand the safety and effectiveness of high-flow nasal prong therapy; in particular, what proportion of children require escalation of therapy, whether any bedside monitoring data predict stability or need for escalation, and complications of the therapies. This was a prospective observational study of the first 6 months after the introduction of high-flow nasal prong oxygen therapy at the Royal Children's Hospital in Melbourne. Data were collected on all children who were managed with either high-flow nasal prong oxygen therapy or nasopharyngeal continuous positive airway pressure. The mode of respiratory support was determined by the treating medical staff. Data were collected on each patient before the use of high-flow nasal prong or nasopharyngeal continuous positive airway pressure, at 2 hours after starting the therapy, and the children were monitored and data collected until discharge from the ICU. Therapy was considered to be escalated if children on high-flow nasal prong required a more invasive form or higher level of respiratory support, including nasopharyngeal continuous positive airway pressure or mask bilevel positive airway pressure or endotracheal intubation and mechanical ventilation. Therapy was considered to be escalated if children on nasopharyngeal continuous positive airway pressure required bilevel positive airway pressure or intubation and mechanical ventilation. As the first mode of respiratory support, 72 children received high-flow nasal prong therapy and 37 received nasopharyngeal continuous positive airway pressure. Forty-four patients (61%) who received high-flow nasal prong first were weaned to low-flow oxygen or to room air and 21 (29%) required escalation of respiratory support, compared with children on nasopharyngeal continuous positive airway pressure: 21 (57%) weaned successfully and 9 (24%) required escalation. Repeated treatment and crossover were common in this cohort. Throughout the study duration, escalation to a higher level of respiratory support was needed in 26 of 100 high-flow nasal prong treatment episodes (26%) and in 10 of 55 continuous positive airway pressure episodes (18%; p = 0.27). The need for escalation could be predicted by two of failure of normalization of heart rate and respiratory rate, and if the FIO2 did not fall to lower than 0.5, 2 hours after starting high-flow nasal prong therapy. Nasopharyngeal continuous positive airway pressure was required for significantly longer periods than high-flow nasal prong (median 48 and 18 hours, respectively; p ≤ 0.001). High-flow nasal prong therapy is a safe form of respiratory support for children with moderate-to-severe respiratory distress, across a large range of diagnoses, whose increased work of breathing or hypoxemia is not relieved by standard oxygen therapy. About one quarter of all children will require escalation to another form of respiratory support. This can be predicted by simple bedside observations.

Investigation of the fuel feed line failures on the Space Shuttle main engine

NASA Technical Reports Server (NTRS)

Larson, E. W.

1980-01-01

The Space Shuttle Main Engine (SSME) development program experienced two similar appearing fuel feed line failures during the shutdown portion of two engine tests. Failure investigations into each incident showed that a few cycles of high-amplitude transient strain occurring during the start and cutoff portions of each test could have either accumulated damage and led to a fatigue failure after 46 tests, or caused rupture in a low-strength weld joint. The cause of the high strain was traced to a period of unsteady flow separation during the start and cutoff of each test coincident with the oblique shock approaching the nozzle exit. Since elimination of the flow separation was impractical, the steps taken to allow engine development and flight preparations to continue were: (1) establish the safe operating life of the nozzle, (2) reinforce all low-strength welds, and (3) eliminate the use of thin-wall fuel feed lines. In parallel, the feed line was redesigned and fabrication was initiated on units to be incorporated into the development program.

Push-pull tracer tests: Their information content and use for characterizing non-Fickian, mobile-immobile behavior: INFORMATION CONTENT OF PUSH-PULL TESTS

DOE PAGES

Hansen, Scott K.; Berkowitz, Brian; Vesselinov, Velimir V.; ...

2016-12-01

Path reversibility and radial symmetry are often assumed in push-pull tracer test analysis. In reality, heterogeneous flow fields mean that both assumptions are idealizations. In this paper, to understand their impact, we perform a parametric study which quantifies the scattering effects of ambient flow, local-scale dispersion, and velocity field heterogeneity on push-pull breakthrough curves and compares them to the effects of mobile-immobile mass transfer (MIMT) processes including sorption and diffusion into secondary porosity. We identify specific circumstances in which MIMT overwhelmingly determines the breakthrough curve, which may then be considered uninformative about drift and local-scale dispersion. Assuming path reversibility, wemore » develop a continuous-time-random-walk-based interpretation framework which is flow-field-agnostic and well suited to quantifying MIMT. Adopting this perspective, we show that the radial flow assumption is often harmless: to the extent that solute paths are reversible, the breakthrough curve is uninformative about velocity field heterogeneity. Our interpretation method determines a mapping function (i.e., subordinator) from travel time in the absence of MIMT to travel time in its presence. A mathematical theory allowing this function to be directly “plugged into” an existing Laplace-domain transport model to incorporate MIMT is presented and demonstrated. Algorithms implementing the calibration are presented and applied to interpretation of data from a push-pull test performed in a heterogeneous environment. A successful four-parameter fit is obtained, of comparable fidelity to one obtained using a million-node 3-D numerical model. In conclusion, we demonstrate analytically and numerically how push-pull tests quantifying MIMT are sensitive to remobilization, but not immobilization, kinetics.« less

Push-pull tracer tests: Their information content and use for characterizing non-Fickian, mobile-immobile behavior: INFORMATION CONTENT OF PUSH-PULL TESTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Scott K.; Berkowitz, Brian; Vesselinov, Velimir V.

Path reversibility and radial symmetry are often assumed in push-pull tracer test analysis. In reality, heterogeneous flow fields mean that both assumptions are idealizations. In this paper, to understand their impact, we perform a parametric study which quantifies the scattering effects of ambient flow, local-scale dispersion, and velocity field heterogeneity on push-pull breakthrough curves and compares them to the effects of mobile-immobile mass transfer (MIMT) processes including sorption and diffusion into secondary porosity. We identify specific circumstances in which MIMT overwhelmingly determines the breakthrough curve, which may then be considered uninformative about drift and local-scale dispersion. Assuming path reversibility, wemore » develop a continuous-time-random-walk-based interpretation framework which is flow-field-agnostic and well suited to quantifying MIMT. Adopting this perspective, we show that the radial flow assumption is often harmless: to the extent that solute paths are reversible, the breakthrough curve is uninformative about velocity field heterogeneity. Our interpretation method determines a mapping function (i.e., subordinator) from travel time in the absence of MIMT to travel time in its presence. A mathematical theory allowing this function to be directly “plugged into” an existing Laplace-domain transport model to incorporate MIMT is presented and demonstrated. Algorithms implementing the calibration are presented and applied to interpretation of data from a push-pull test performed in a heterogeneous environment. A successful four-parameter fit is obtained, of comparable fidelity to one obtained using a million-node 3-D numerical model. In conclusion, we demonstrate analytically and numerically how push-pull tests quantifying MIMT are sensitive to remobilization, but not immobilization, kinetics.« less

International Space Station Cathode Life Testing

NASA Technical Reports Server (NTRS)

Soulas, George C.; Sarver-Verhey, Timothy R.

1997-01-01

Four hollow cathode assembly (HCA) life tests were initiated at operating conditions simulating on-orbit operation of the International Space Station plasma contactor. The objective of these tests is to demonstrate the mission-required 18,000 hour lifetime with high-fidelity development model HCAS. HCAs are operated with a continuous 6 sccm xenon flow rate and 3 A anode current. On-orbit emission current requirements are simulated with a square waveform consisting of 50 minutes at a 2.5 A emission current and 40 minutes with no emission current. One HCA test was terminated after approximately 8,000 hours so that a destructive analysis could be performed. The analysis revealed no life-limiting processes and the ultimate lifetime was projected to be greater than the mission requirement. Testing continues for the remaining three HCAs which have accumulated approximately 8,000 hours, 10,000 hours, and 11,000 hours, respectively, as of June 1997. Anode and bias voltages, strong indicators of cathode electron emitter condition, are within acceptable ranges and have exhibited no life- or performance-limiting phenomena to date.

Multi-version software reliability through fault-avoidance and fault-tolerance

NASA Technical Reports Server (NTRS)

Vouk, Mladen A.; Mcallister, David F.

1989-01-01

A number of experimental and theoretical issues associated with the practical use of multi-version software to provide run-time tolerance to software faults were investigated. A specialized tool was developed and evaluated for measuring testing coverage for a variety of metrics. The tool was used to collect information on the relationships between software faults and coverage provided by the testing process as measured by different metrics (including data flow metrics). Considerable correlation was found between coverage provided by some higher metrics and the elimination of faults in the code. Back-to-back testing was continued as an efficient mechanism for removal of un-correlated faults, and common-cause faults of variable span. Software reliability estimation methods was also continued based on non-random sampling, and the relationship between software reliability and code coverage provided through testing. New fault tolerance models were formulated. Simulation studies of the Acceptance Voting and Multi-stage Voting algorithms were finished and it was found that these two schemes for software fault tolerance are superior in many respects to some commonly used schemes. Particularly encouraging are the safety properties of the Acceptance testing scheme.

Kerosene-Fuel Engine Testing Under Way

NASA Image and Video Library

2003-11-17

NASA Stennis Space Center engineers conducted a successful cold-flow test of an RS-84 engine component Sept. 24. The RS-84 is a reusable engine fueled by rocket propellant - a special blend of kerosene - designed to power future flight vehicles. Liquid oxygen was blown through the RS-84 subscale preburner to characterize the test facility's performance and the hardware's resistance. Engineers are now moving into the next phase, hot-fire testing, which is expected to continue into February 2004. The RS-84 engine prototype, developed by the Rocketdyne Propulsion and Power division of The Boeing Co. of Canoga Park, Calif., is one of two competing Rocket Engine Prototype technologies - a key element of NASA's Next Generation Launch Technology program.

Kerosene-Fuel Engine Testing Under Way

NASA Technical Reports Server (NTRS)

2003-01-01

NASA Stennis Space Center engineers conducted a successful cold-flow test of an RS-84 engine component Sept. 24. The RS-84 is a reusable engine fueled by rocket propellant - a special blend of kerosene - designed to power future flight vehicles. Liquid oxygen was blown through the RS-84 subscale preburner to characterize the test facility's performance and the hardware's resistance. Engineers are now moving into the next phase, hot-fire testing, which is expected to continue into February 2004. The RS-84 engine prototype, developed by the Rocketdyne Propulsion and Power division of The Boeing Co. of Canoga Park, Calif., is one of two competing Rocket Engine Prototype technologies - a key element of NASA's Next Generation Launch Technology program.

Internal Mixing Studied for GE/ARL Ejector Nozzle

NASA Technical Reports Server (NTRS)

Zaman, Khairul

2005-01-01

To achieve jet noise reduction goals for the High Speed Civil Transport aircraft, researchers have been investigating the mixer-ejector nozzle concept. For this concept, a primary nozzle with multiple chutes is surrounded by an ejector. The ejector mixes low-momentum ambient air with the hot engine exhaust to reduce the jet velocity and, hence, the jet noise. It is desirable to mix the two streams as fast as possible in order to minimize the length and weight of the ejector. An earlier model of the mixer-ejector nozzle was tested extensively in the Aerodynamic Research Laboratory (ARL) of GE Aircraft Engines at Cincinnati, Ohio. While testing was continuing with later generations of the nozzle, the earlier model was brought to the NASA Lewis Research Center for relatively fundamental measurements. Goals of the Lewis study were to obtain details of the flow field to aid computational fluid dynamics (CFD) efforts and obtain a better understanding of the flow mechanisms, as well as to experiment with mixing enhancement devices, such as tabs. The measurements were made in an open jet facility for cold (unheated) flow without a surrounding coflowing stream.

Continuous flow nitration in miniaturized devices

PubMed Central

2014-01-01

Summary This review highlights the state of the art in the field of continuous flow nitration with miniaturized devices. Although nitration has been one of the oldest and most important unit reactions, the advent of miniaturized devices has paved the way for new opportunities to reconsider the conventional approach for exothermic and selectivity sensitive nitration reactions. Four different approaches to flow nitration with microreactors are presented herein and discussed in view of their advantages, limitations and applicability of the information towards scale-up. Selected recent patents that disclose scale-up methodologies for continuous flow nitration are also briefly reviewed. PMID:24605161

Two-dimensional distribution of microbial activity and flow patterns within naturally fractured chalk.

PubMed

Arnon, Shai; Ronen, Zeev; Adar, Eilon; Yakirevich, Alexander; Nativ, Ronit

2005-10-01

The two-dimensional distribution of flow patterns and their dynamic change due to microbial activity were investigated in naturally fractured chalk cores. Long-term biodegradation experiments were conducted in two cores ( approximately 20 cm diameter, 31 and 44 cm long), intersected by a natural fracture. 2,4,6-tribromophenol (TBP) was used as a model contaminant and as the sole carbon source for aerobic microbial activity. The transmissivity of the fractures was continuously reduced due to biomass accumulation in the fracture concurrent with TBP biodegradation. From multi-tracer experiments conducted prior to and following the microbial activity, it was found that biomass accumulation causes redistribution of the preferential flow channels. Zones of slow flow near the fracture inlet were clogged, thus further diverting the flow through zones of fast flow, which were also partially clogged. Quantitative evaluation of biodegradation and bacterial counts supported the results of the multi-tracer tests, indicating that most of the bacterial activity occurs close to the inlet. The changing flow patterns, which control the nutrient supply, resulted in variations in the concentrations of the chemical constituents (TBP, bromide and oxygen), used as indicators of biodegradation.

Fusion–fission experiments in Aphidius: evolutionary split without isolation in response to environmental bimodality

PubMed Central

Emelianov, I; Hernandes-Lopez, A; Torrence, M; Watts, N

2011-01-01

Studying host-based divergence naturally maintained by a balance between selection and gene flow can provide valuable insights into genetic underpinnings of host adaptation and ecological speciation in parasites. Selection-gene flow balance is often postulated in sympatric host races, but direct experimental evidence is scarce. In this study, we present such evidence obtained in host races of Aphidius ervi, an important hymenopteran agent of biological control of aphids in agriculture, using a novel fusion–fission method of gene flow perturbation. In our study, between-race genetic divergence was obliterated by means of advanced hybridisation, followed by a multi-generation exposure of the resulting genetically uniform hybrid swarm to a two-host environment. This fusion–fission procedure was implemented under two contrasting regimes of between-host gene flow in two replicated experiments involving different racial pairs. Host-based genetic fission in response to environmental bimodality occurred in both experiments in as little as six generations of divergent adaptation despite continuous gene flow. We demonstrate that fission recovery of host-based divergence evolved faster and hybridisation-induced linkage disequilibrium decayed slower under restricted (6.7%) compared with unrestricted gene flow, directly pointing at a balance between gene flow and divergent selection. We also show, in four separate tests, that random drift had no or little role in the observed genetic split. Rates and patterns of fission divergence differed between racial pairs. Comparative linkage analysis of these differences is currently under way to test for the role of genomic architecture of adaptation in ecology-driven divergent evolution. PMID:20924399

Low-flow characteristics of Virginia streams

USGS Publications Warehouse

Austin, Samuel H.; Krstolic, Jennifer L.; Wiegand, Ute

2011-01-01

Low-flow annual non-exceedance probabilities (ANEP), called probability-percent chance (P-percent chance) flow estimates, regional regression equations, and transfer methods are provided describing the low-flow characteristics of Virginia streams. Statistical methods are used to evaluate streamflow data. Analysis of Virginia streamflow data collected from 1895 through 2007 is summarized. Methods are provided for estimating low-flow characteristics of gaged and ungaged streams. The 1-, 4-, 7-, and 30-day average streamgaging station low-flow characteristics for 290 long-term, continuous-record, streamgaging stations are determined, adjusted for instances of zero flow using a conditional probability adjustment method, and presented for non-exceedance probabilities of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.02, 0.01, and 0.005. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression equations to estimate annual non-exceedance probabilities at gaged and ungaged sites and are summarized for 290 long-term, continuous-record streamgaging stations, 136 short-term, continuous-record streamgaging stations, and 613 partial-record streamgaging stations. Regional regression equations for six physiographic regions use basin characteristics to estimate 1-, 4-, 7-, and 30-day average low-flow annual non-exceedance probabilities at gaged and ungaged sites. Weighted low-flow values that combine computed streamgaging station low-flow characteristics and annual non-exceedance probabilities from regional regression equations provide improved low-flow estimates. Regression equations developed using the Maintenance of Variance with Extension (MOVE.1) method describe the line of organic correlation (LOC) with an appropriate index site for low-flow characteristics at 136 short-term, continuous-record streamgaging stations and 613 partial-record streamgaging stations. Monthly streamflow statistics computed on the individual daily mean streamflows of selected continuous-record streamgaging stations and curves describing flow-duration are presented. Text, figures, and lists are provided summarizing low-flow estimates, selected low-flow sites, delineated physiographic regions, basin characteristics, regression equations, error estimates, definitions, and data sources. This study supersedes previous studies of low flows in Virginia.

Electrohydrodynamics and other hydrodynamic phenomena in continuous flow electrophoresis

NASA Technical Reports Server (NTRS)

Saville, D. A.

1982-01-01

The process known as continuous flow electrophoresis employs an electric field to separate the constituents of particulate samples suspended in a liquid. Complications arise because the electric field generates temperature gradients due to Joule heating and derives an electrohydrodynamic crossflow. Several aspects of the flow are discussed including entrance effects, hydrodynamic stability and a flow restructuring due to the combined effects of buoyancy and the crossflow.

Multiphysics numerical modeling of the continuous flow microwave-assisted transesterification process.

PubMed

Muley, Pranjali D; Boldor, Dorin

2012-01-01

Use of advanced microwave technology for biodiesel production from vegetable oil is a relatively new technology. Microwave dielectric heating increases the process efficiency and reduces reaction time. Microwave heating depends on various factors such as material properties (dielectric and thermo-physical), frequency of operation and system design. Although lab scale results are promising, it is important to study these parameters and optimize the process before scaling up. Numerical modeling approach can be applied for predicting heating and temperature profiles including at larger scale. The process can be studied for optimization without actually performing the experiments, reducing the amount of experimental work required. A basic numerical model of continuous electromagnetic heating of biodiesel precursors was developed. A finite element model was built using COMSOL Multiphysics 4.2 software by coupling the electromagnetic problem with the fluid flow and heat transfer problem. Chemical reaction was not taken into account. Material dielectric properties were obtained experimentally, while the thermal properties were obtained from the literature (all the properties were temperature dependent). The model was tested for the two different power levels 4000 W and 4700 W at a constant flow rate of 840ml/min. The electric field, electromagnetic power density flow and temperature profiles were studied. Resulting temperature profiles were validated by comparing to the temperatures obtained at specific locations from the experiment. The results obtained were in good agreement with the experimental data.

Admixture and gene flow from Russia in the recovering Northern European brown bear (Ursus arctos).

PubMed

Kopatz, Alexander; Eiken, Hans Geir; Aspi, Jouni; Kojola, Ilpo; Tobiassen, Camilla; Tirronen, Konstantin F; Danilov, Pjotr I; Hagen, Snorre B

2014-01-01

Large carnivores were persecuted to near extinction during the last centuries, but have now recovered in some countries. It has been proposed earlier that the recovery of the Northern European brown bear is supported by migration from Russia. We tested this hypothesis by obtaining for the first time continuous sampling of the whole Finnish bear population, which is located centrally between the Russian and Scandinavian bear populations. The Finnish population is assumed to experience high gene flow from Russian Karelia. If so, no or a low degree of genetic differentiation between Finnish and Russian bears could be expected. We have genotyped bears extensively from all over Finland using 12 validated microsatellite markers and compared their genetic composition to bears from Russian Karelia, Sweden, and Norway. Our fine masked investigation identified two overlapping genetic clusters structured by isolation-by-distance in Finland (pairwise FST = 0.025). One cluster included Russian bears, and migration analyses showed a high number of migrants from Russia into Finland, providing evidence of eastern gene flow as an important driver during recovery. In comparison, both clusters excluded bears from Sweden and Norway, and we found no migrants from Finland in either country, indicating that eastern gene flow was probably not important for the population recovery in Scandinavia. Our analyses on different spatial scales suggest a continuous bear population in Finland and Russian Karelia, separated from Scandinavia.

Admixture and Gene Flow from Russia in the Recovering Northern European Brown Bear (Ursus arctos)

PubMed Central

Kopatz, Alexander; Eiken, Hans Geir; Aspi, Jouni; Kojola, Ilpo; Tobiassen, Camilla; Tirronen, Konstantin F.; Danilov, Pjotr I.; Hagen, Snorre B.

2014-01-01

Large carnivores were persecuted to near extinction during the last centuries, but have now recovered in some countries. It has been proposed earlier that the recovery of the Northern European brown bear is supported by migration from Russia. We tested this hypothesis by obtaining for the first time continuous sampling of the whole Finnish bear population, which is located centrally between the Russian and Scandinavian bear populations. The Finnish population is assumed to experience high gene flow from Russian Karelia. If so, no or a low degree of genetic differentiation between Finnish and Russian bears could be expected. We have genotyped bears extensively from all over Finland using 12 validated microsatellite markers and compared their genetic composition to bears from Russian Karelia, Sweden, and Norway. Our fine masked investigation identified two overlapping genetic clusters structured by isolation-by-distance in Finland (pairwise FST = 0.025). One cluster included Russian bears, and migration analyses showed a high number of migrants from Russia into Finland, providing evidence of eastern gene flow as an important driver during recovery. In comparison, both clusters excluded bears from Sweden and Norway, and we found no migrants from Finland in either country, indicating that eastern gene flow was probably not important for the population recovery in Scandinavia. Our analyses on different spatial scales suggest a continuous bear population in Finland and Russian Karelia, separated from Scandinavia. PMID:24839968

Increasing Sensitivity In Continuous-Flow Electrophoresis

NASA Technical Reports Server (NTRS)

Sharnez, Rizwan; Sammons, David W.

1994-01-01

Sensitivity of continuous-flow electrophoresis (CFE) chamber increased by introducing lateral gradients in concentration of buffer solution and thickness of chamber. Such gradients, with resulting enhanced separation, achieved in CFE chamber with wedge-shaped cross section and collateral flow. Enables improved separations of homogeneous components of mixtures of variety of biologically important substances.

Zero entropy continuous interval maps and MMLS-MMA property

NASA Astrophysics Data System (ADS)

Jiang, Yunping

2018-06-01

We prove that the flow generated by any continuous interval map with zero topological entropy is minimally mean-attractable and minimally mean-L-stable. One of the consequences is that any oscillating sequence is linearly disjoint from all flows generated by all continuous interval maps with zero topological entropy. In particular, the Möbius function is linearly disjoint from all flows generated by all continuous interval maps with zero topological entropy (Sarnak’s conjecture for continuous interval maps). Another consequence is a non-trivial example of a flow having discrete spectrum. We also define a log-uniform oscillating sequence and show a result in ergodic theory for comparison. This material is based upon work supported by the National Science Foundation. It is also partially supported by a collaboration grant from the Simons Foundation (grant number 523341) and PSC-CUNY awards and a grant from NSFC (grant number 11571122).

A Novel Imaging Method for the Cartilaginous Eustachian Tube Lumen: Computerized Tomography During the Forced Response Test.

PubMed

Alper, Cuneyt M; Rath, Tanya J; Teixeira, Miriam S; Swarts, J Douglas

2018-01-01

In vivo imaging of the open cartilaginous Eustachian tube (ET) lumen by computed tomography (CT) scan during ET function (ETF) testing to establish new methodology. Five adults underwent unilateral ETF testing of an ear with a nonintact tympanic membrane using the forced response test (FRT) to measure the opening pressure (PO), steady state pressure (PS), and flow conductance (CS). Then at baseline and during the PS phase of the FRT, a temporal-bone CT scan with continuous 0.625 mm thickness was obtained. Multiplanar oblique reformats along the axis of the ET were created, and point value and region of interest (ROI) Hounsfield unit measurements were recorded from the location of the ET lumen. At the FRT flow rate of 11 ml/min, the average PO, PS, and CS were 370.5 daPa, 119.6 daPa, and 0.16 ml/min/daPa, respectively. For flow rates of 23 and 46 ml/min, these values were 236.2, 204.2, 0.12 and 385.5, 321.1, 0.18, respectively. Although areas with lower attenuation were suggestive of air density, a distinct air-filled cartilaginous ET lumen could not be confirmed. While the current imaging parameters failed to resolve the air-soft tissue interface throughout the open cartilaginous ET, further advances in imaging may obviate this limitation.

Design and performance of a 4He-evaporator at <1.0 K

NASA Astrophysics Data System (ADS)

Das, N. K.; Pradhan, J.; Naser, Md. Z. A.; Roy, A.; Mandal, B. Ch.; Mallik, C.; Bhandari, R. K.

2012-12-01

A helium evaporator for obtaining 1 K temperature has been built and tested in laboratory. This will function primarily as the precooling stage for the circulating helium isotopic gas mixture. This works on evaporative cooling by way of pumping out the vapour from the top of the pot. A precision needle valve is used initially to fill up the pot and subsequently a permanent flow impedance maintains the helium flow from the bath into the pot to replenish the evaporative loss of helium. Considering the cooling power of 10 mW @1.0 K, a 99.0 cm3 helium evaporator was designed, fabricated from OFE copper and tested in the laboratory. A pumping station comprising of a roots pump backed by a dry pump was used for evacuation. The calibrated RuO thermometer and kapton film heater were used for measuring the temperature and cooling power of the system respectively. The continuously filled 1 K bath is tested in the laboratory and found to offer a temperature less than 1.0 K by withdrawing vapour from the evaporator. In order to minimize the heat load and to prevent film creep across the pumping tube, size optimization of the pumping line and pump-out port has been performed. The results of test run along with relevant analysis, mechanical fabrication of flow impedance are presented here.

Advanced Gas Turbine (AGT): Power-train system development

NASA Technical Reports Server (NTRS)

Helms, H. E.; Johnson, R. A.; Gibson, R. K.; Smith, L. B.

1983-01-01

Technical work on the design and effort leading to the testing of a 74.5 kW (100 hp) automotive gas turbine is described. The general effort was concentrated on building an engine for test starting in July. The buildup progressed with only routine problems and the engine was delivered to the test stand 9 July. In addition to the engine build effort, work continued in selected component areas. Ceramic turbine parts were built and tested. Burst tests of ceramic rotors show strengths are approaching that achieved in test bars; proof testing is required for acceptable strength ceramic vanes. Over 25 hours was accumulated on the combustor rig in three test modes: pilot nozzle only, start nozzle, and main nozzle operation. Satisfactory ignition was achieved for a wide range of starting speeds and the lean blowout limit was as low as 0.06 kg/b (0.14 lb/hr). Lean blowout was more a function of nozzle atomization than fuel/air ratio. A variety of cycle points were tested. Transition from start nozzle flow to main nozzle flow was done manually without difficulty. Regenerator parts were qualification tested without incident and the parts were assembled on schedule. Rig based performance matched first build requirements. Repeated failures in the harmonic drive gearbox during rig testing resulted in that concept being abandoned for an alternate scheme.

Simulating the gas hydrate production test at Mallik using the pilot scale pressure reservoir LARS

NASA Astrophysics Data System (ADS)

Heeschen, Katja; Spangenberg, Erik; Schicks, Judith M.; Priegnitz, Mike; Giese, Ronny; Luzi-Helbing, Manja

2014-05-01

LARS, the LArge Reservoir Simulator, allows for one of the few pilot scale simulations of gas hydrate formation and dissociation under controlled conditions with a high resolution sensor network to enable the detection of spatial variations. It was designed and built within the German project SUGAR (submarine gas hydrate reservoirs) for sediment samples with a diameter of 0.45 m and a length of 1.3 m. During the project, LARS already served for a number of experiments simulating the production of gas from hydrate-bearing sediments using thermal stimulation and/or depressurization. The latest test simulated the methane production test from gas hydrate-bearing sediments at the Mallik test site, Canada, in 2008 (Uddin et al., 2011). Thus, the starting conditions of 11.5 MPa and 11°C and environmental parameters were set to fit the Mallik test site. The experimental gas hydrate saturation of 90% of the total pore volume (70 l) was slightly higher than volumes found in gas hydrate-bearing formations in the field (70 - 80%). However, the resulting permeability of a few millidarcy was comparable. The depressurization driven gas production at Mallik was conducted in three steps at 7.0 MPa - 5.0 MPa - 4.2 MPa all of which were used in the laboratory experiments. In the lab the pressure was controlled using a back pressure regulator while the confining pressure was stable. All but one of the 12 temperature sensors showed a rapid decrease in temperature throughout the sediment sample, which accompanied the pressure changes as a result of gas hydrate dissociation. During step 1 and 2 they continued up to the point where gas hydrate stability was regained. The pressure decreases and gas hydrate dissociation led to highly variable two phase fluid flow throughout the duration of the simulated production test. The flow rates were measured continuously (gas) and discontinuously (liquid), respectively. Next to being discussed here, both rates were used to verify a model of gas hydrate dissociation applying the foamy oil approach, a method earlier adopted to model the Mallik production test (see abstract Abendroth et al., this volume). Combined with a dense set of data from a cylindrical electrical resistance tomography (ERT) array (see abstract Priegnitz et al., this volume), very valuable information were gained on the spatial as well as temporal formation and dissociation of gas hydrates as well as changes in permeability and resulting pathways for the fluid flow. Here we present the set-up and execution of the experiment and discuss the results from temperature and flow measurements with respect to the gas hydrate dissociation and characteristics of resulting fluid flow. Uddin, M., Wright, F., and Coombe, D. 2011. Numerical Study of Gas Evolution and Transport Behaviours in Natural Gas-Hydrate Reservoirs. Journal of Canadian Petroleum Technology 50, 70-89.

Pressurized tundish for controlling a continuous flow of molten metal

DOEpatents

Lewis, T.W.; Hamill, P.E. Jr.; Ozgu, M.R.; Padfield, R.C.; Rego, D.N.; Brita, G.P.

1990-07-24

A pressurized tundish for controlling a continuous flow of molten metal is characterized by having a pair of principal compartments, one being essentially unpressurized and receiving molten metal introduced thereto, and the other being adapted for maintaining a controlled gaseous pressure over the surface of the fluid metal therein, whereby, by controlling the pressure within the pressurized chamber, metal exiting from the tundish is made to flow continually and at a controlled rate. 1 fig.

Quantification of instantaneous flow rate and dynamically changing effective orifice area using a geometry independent three-dimensional digital color Doppler method: An in vitro study mimicking mitral regurgitation.

PubMed

Li, Xiaokui; Wanitkun, Suthep; Li, Xiang-Ning; Hashimoto, Ikuo; Mori, Yoshiki; Rusk, Rosemary A; Hicks, Shannon E; Sahn, David J

2002-10-01

Our study was intended to test the accuracy of a 3-dimensional (3D) digital color Doppler flow convergence (FC) method for assessing the effective orifice area (EOA) in a new dynamic orifice model mimicking a variety of mitral regurgitation. FC surface area methods for detecting EOA have been reported to be useful for quantifying the severity of valvular regurgitation. With our new 3D digital direct FC method, all raw velocity data are available and variable Nyquist limits can be selected for computation of direct FC surface area for computing instantaneous flow rate and temporal change of EOA. A 7.0-MHz multiplane transesophageal probe from an ultrasound system (ATL HDI 5000) was linked and controlled by a computer workstation to provide 3D images. Three differently shaped latex orifices (zigzag, arc, and straight slit, each with cutting-edge length of 1 cm) were used to mimic the dynamic orifice of mitral regurgitation. 3D FC surface computation was performed on parallel slices through the 3D data set at aliasing velocities (14-48 cm/s) selected to maximize the regularity and minimize lateral dropout of the visualized 3D FC at 5 points per cardiac cycle. Using continuous wave velocity for each, 3D-calculated EOA was compared with EOA determined by using continuous wave Doppler and the flow rate from a reference ultrasonic flow meter. Simultaneous digital video images were also recorded to define the actual orifice size for 9 stroke volumes (15-55 mL/beat with maximum flow rates 45-182 mL/s). Over the 9 pulsatile flow states and 3 orifices, 3D FC EOAs (0.05-0.63 cm(2)) from different phases of the cardiac cycle in each pump setting correlated well with reference EOA (r = 0.89-0.92, SEE = 0.027-0.055cm(2)) and they also correlated well with digital video images of the actual orifice peak (r = 0.97-0.98, SEE = 0.016-0.019 cm(2)), although they were consistently smaller, as expected by the contraction coefficient. The digital 3D FC method can accurately predict flow rate, and, thus, EOA (in conjunction with continuous wave Doppler), because it allows direct FC surface measurement despite temporal variability of FC shape.

Verification and Validation Studies for the LAVA CFD Solver

NASA Technical Reports Server (NTRS)

Moini-Yekta, Shayan; Barad, Michael F; Sozer, Emre; Brehm, Christoph; Housman, Jeffrey A.; Kiris, Cetin C.

2013-01-01

The verification and validation of the Launch Ascent and Vehicle Aerodynamics (LAVA) computational fluid dynamics (CFD) solver is presented. A modern strategy for verification and validation is described incorporating verification tests, validation benchmarks, continuous integration and version control methods for automated testing in a collaborative development environment. The purpose of the approach is to integrate the verification and validation process into the development of the solver and improve productivity. This paper uses the Method of Manufactured Solutions (MMS) for the verification of 2D Euler equations, 3D Navier-Stokes equations as well as turbulence models. A method for systematic refinement of unstructured grids is also presented. Verification using inviscid vortex propagation and flow over a flat plate is highlighted. Simulation results using laminar and turbulent flow past a NACA 0012 airfoil and ONERA M6 wing are validated against experimental and numerical data.

A genuinely discontinuous approach for multiphase EHD problems

NASA Astrophysics Data System (ADS)

Natarajan, Mahesh; Desjardins, Olivier

2017-11-01

Electrohydrodynamics (EHD) involves solving the Poisson equation for the electric field potential. For multiphase flows, although the electric field potential is a continuous quantity, due to the discontinuity in the electric permittivity between the phases, additional jump conditions at the interface, for the normal and tangential components of the electric field need to be satisfied. All approaches till date either ignore the jump conditions, or involve simplifying assumptions, and hence yield unconvincing results even for simple test problems. In the present work, we develop a genuinely discontinuous approach for the Poisson equation for multiphase flows using a Finite Volume Unsplit Volume of Fluid method. The governing equation and the jump conditions without assumptions are used to develop the method, and its efficiency is demonstrated by comparison of the numerical results with canonical test problems having exact solutions. Postdoctoral Associate, Department of Mechanical and Aerospace Engineering.

Oscillatory multiphase flow strategy for chemistry and biology.

PubMed

Abolhasani, Milad; Jensen, Klavs F

2016-07-19

Continuous multiphase flow strategies are commonly employed for high-throughput parameter screening of physical, chemical, and biological processes as well as continuous preparation of a wide range of fine chemicals and micro/nano particles with processing times up to 10 min. The inter-dependency of mixing and residence times, and their direct correlation with reactor length have limited the adaptation of multiphase flow strategies for studies of processes with relatively long processing times (0.5-24 h). In this frontier article, we describe an oscillatory multiphase flow strategy to decouple mixing and residence times and enable investigation of longer timescale experiments than typically feasible with conventional continuous multiphase flow approaches. We review current oscillatory multiphase flow technologies, provide an overview of the advancements of this relatively new strategy in chemistry and biology, and close with a perspective on future opportunities.

Natural Length Scales Shape Liquid Phase Continuity in Unsaturated Flows

NASA Astrophysics Data System (ADS)

Assouline, S.; Lehmann, P. G.; Or, D.

2015-12-01

Unsaturated flows supporting soil evaporation and internal drainage play an important role in various hydrologic and climatic processes manifested at a wide range of scales. We study inherent natural length scales that govern these flow processes and constrain the spatial range of their representation by continuum models. These inherent length scales reflect interactions between intrinsic porous medium properties that affect liquid phase continuity, and the interplay among forces that drive and resist unsaturated flow. We have defined an intrinsic length scale for hydraulic continuity based on pore size distribution that controls soil evaporation dynamics (i.e., stage 1 to stage 2 transition). This simple metric may be used to delineate upper bounds for regional evaporative losses or the depth of soil-atmosphere interactions (in the absence of plants). A similar length scale governs the dynamics of internal redistribution towards attainment of field capacity, again through its effect on hydraulic continuity in the draining porous medium. The study provides a framework for guiding numerical and mathematical models for capillary flows across different scales considering the necessary conditions for coexistence of stationarity (REV), hydraulic continuity and intrinsic capillary gradients.

Numerical optimization using flow equations.

PubMed

Punk, Matthias

2014-12-01

We develop a method for multidimensional optimization using flow equations. This method is based on homotopy continuation in combination with a maximum entropy approach. Extrema of the optimizing functional correspond to fixed points of the flow equation. While ideas based on Bayesian inference such as the maximum entropy method always depend on a prior probability, the additional step in our approach is to perform a continuous update of the prior during the homotopy flow. The prior probability thus enters the flow equation only as an initial condition. We demonstrate the applicability of this optimization method for two paradigmatic problems in theoretical condensed matter physics: numerical analytic continuation from imaginary to real frequencies and finding (variational) ground states of frustrated (quantum) Ising models with random or long-range antiferromagnetic interactions.

Numerical optimization using flow equations

NASA Astrophysics Data System (ADS)

Punk, Matthias

2014-12-01

We develop a method for multidimensional optimization using flow equations. This method is based on homotopy continuation in combination with a maximum entropy approach. Extrema of the optimizing functional correspond to fixed points of the flow equation. While ideas based on Bayesian inference such as the maximum entropy method always depend on a prior probability, the additional step in our approach is to perform a continuous update of the prior during the homotopy flow. The prior probability thus enters the flow equation only as an initial condition. We demonstrate the applicability of this optimization method for two paradigmatic problems in theoretical condensed matter physics: numerical analytic continuation from imaginary to real frequencies and finding (variational) ground states of frustrated (quantum) Ising models with random or long-range antiferromagnetic interactions.

The continuous similarity model of bulk soil-water evaporation

NASA Technical Reports Server (NTRS)

Clapp, R. B.

1983-01-01

The continuous similarity model of evaporation is described. In it, evaporation is conceptualized as a two stage process. For an initially moist soil, evaporation is first climate limited, but later it becomes soil limited. During the latter stage, the evaporation rate is termed evaporability, and mathematically it is inversely proportional to the evaporation deficit. A functional approximation of the moisture distribution within the soil column is also included in the model. The model was tested using data from four experiments conducted near Phoenix, Arizona; and there was excellent agreement between the simulated and observed evaporation. The model also predicted the time of transition to the soil limited stage reasonably well. For one of the experiments, a third stage of evaporation, when vapor diffusion predominates, was observed. The occurrence of this stage was related to the decrease in moisture at the surface of the soil. The continuous similarity model does not account for vapor flow. The results show that climate, through the potential evaporation rate, has a strong influence on the time of transition to the soil limited stage. After this transition, however, bulk evaporation is independent of climate until the effects of vapor flow within the soil predominate.

On-sun testing of an advanced falling particle receiver system

NASA Astrophysics Data System (ADS)

Ho, Clifford K.; Christian, Joshua M.; Yellowhair, Julius; Siegel, Nathan; Jeter, Sheldon; Golob, Matthew; Abdel-Khalik, Said I.; Nguyen, Clayton; Al-Ansary, Hany

2016-05-01

A 1 MWth high-temperature falling particle receiver was constructed and tested at the National Solar Thermal Test Facility at Sandia National Laboratories. The continuously recirculating system included a particle elevator, top and bottom hoppers, and a cavity receiver that comprised a staggered array of porous chevron-shaped mesh structures that slowed the particle flow through the concentrated solar flux. Initial tests were performed with a peak irradiance of ~300 kW/m2 and a particle mass flow rate of 3.3 kg/s. Peak particle temperatures reached over 700 °C near the center of the receiver, but the particle temperature increase near the sides was lower due to a non-uniform irradiance distribution. At a particle inlet temperature of ~440 °C, the particle temperature increase was 27 °C per meter of drop length, and the thermal efficiency was ~60% for an average irradiance of 110 kW/m2. At an average irradiance of 211 kW/m2, the particle temperature increase was 57.1 °C per meter of drop length, and the thermal efficiency was ~65%. Tests with higher irradiances are being performed and are expected to yield greater particle temperature increases and efficiencies.

Continuous xylanase production with Aspergillus nidulans under pyridoxine limitation using a trickle bed reactor.

PubMed

Müller, Michael; Prade, Rolf A; Segato, Fernando; Atiyeh, Hasan K; Wilkins, Mark R

2015-01-01

A trickle bed reactor (TBR) with recycle was designed and tested using Aspergillus nidulans with a pyridoxine marker and over-expressing/secreting recombinant client xylanase B (XynB). The pyridoxine marker prevented the fungus from synthesizing its own pyridoxine and fungus was unable to grow when no pyridoxine was present in the medium; however, enzyme production was unaffected. Uncontrolled mycelia growth that led to clogging of the TBR was observed when fungus without a pyridoxine marker was used for XynB production. Using the fungus with pyridoxine marker, the TBR was operated continuously for 18 days and achieved a XynB output of 41 U/ml with an influent and effluent flow rate of 0.5 ml/min and a recycle flow rate of 56 ml/min. Production yields in the TBR were 1.4 times greater than a static tray culture and between 1.1 and 67 times greater than yields for SSF enzyme production stated in the literature. Copyright © 2015 Elsevier Ltd. All rights reserved.

High power Nb-doped LiFePO4 Li-ion battery cathodes; pilot-scale synthesis and electrochemical properties

NASA Astrophysics Data System (ADS)

Johnson, Ian D.; Blagovidova, Ekaterina; Dingwall, Paul A.; Brett, Dan J. L.; Shearing, Paul R.; Darr, Jawwad A.

2016-09-01

High power, phase-pure Nb-doped LiFePO4 (LFP) nanoparticles are synthesised using a pilot-scale continuous hydrothermal flow synthesis process (production rate of 6 kg per day) in the range 0.01-2.00 at% Nb with respect to total transition metal content. EDS analysis suggests that Nb is homogeneously distributed throughout the structure. The addition of fructose as a reagent in the hydrothermal flow process, followed by a post synthesis heat-treatment, affords a continuous graphitic carbon coating on the particle surfaces. Electrochemical testing reveals that cycling performance improves with increasing dopant concentration, up to a maximum of 1.0 at% Nb, for which point a specific capacity of 110 mAh g-1 is obtained at 10 C (6 min for the charge or discharge). This is an excellent result for a high power cathode LFP based material, particularly when considering the synthesis was performed on a large pilot-scale apparatus.

Discontinuation of antithrombotic therapy for a year or more in patients with continuous-flow left ventricular assist devices.

PubMed

Pereira, Naveen L; Chen, Dong; Kushwaha, Sudhir S; Park, Soon J

2010-10-01

The recommended anticoagulation regimen during continuous-flow axial left ventricular assist device (LVAD) support is aspirin and warfarin with a targeted international normalized ratio of 2.0-3.0. We report two patients in whom recurrent gastrointestinal bleeding during LVAD support necessitated discontinuation of this anti-thrombotic regimen for a year or more. Despite this, neither patients developed thrombotic complications during 29 patient-months of follow-up. An acquired von Willebrand factor (VWF) abnormality reflected by the absence or decreased abundance of the highest molecular weight multimers was demonstrated in both patients. The gold standard test for platelet function, light transmission platelet aggregometry was measured in one patient and was normal, indicative that the predominant abnormality in the coagulation profile of these patients is an acquired VWF syndrome. Clinical trials are required to address the question whether it is safe to discontinue anticoagulation in LVAD patients with acquired VWF abnormalities.

Performance evaluation of a continuous-flow bioanode microbial electrolysis cell fed with furanic and phenolic compounds

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2016-07-04

Furanic and phenolic compounds, formed during the pretreatment of lignocellulosic biomass, are problematic byproducts in down-stream biofuel processes. A microbial electrolysis cell (MEC) is an alternative technology to handle furanic and phenolic compounds and produce renewable hydrogen (H 2). In this study, we evaluated the performance of a continuous-flow bioanode MEC fed with furanic and phenolic compounds at different operating conditions. All hydraulic retention times (HRTs) tested (6-24 h) resulted in complete transformation of the parent compounds at an organic loading rate (OLR) of 0.2g L -1 per d and applied voltage of 0.6 V. Increasing the OLR to 0.8more » g L -1 per d at an HRT of 6h resulted in an increased H 2 production rate from 0.07 to 0.14 L L anode 1 per d, but an OLR of 3.2 g L -1 per d did not lead to a higher H 2 production rate. Significant methane production was observed at an OLR of 3.2 g L -1 per d. The lack of increased H 2 production at the highest OLR tested was due to a limited rate of exoelectrogenesis but not fermentation, evidenced by the accumulation of high acetate levels and higher growth of fermenters and methanogens over exoelectrogens. Increasing applied voltage from 0.6 to 1.0V at an OLR of 3.2 g L -1 per d and HRT of 6h enhanced exoelectrogenesis and resulted in a 1.7-fold increase of H 2 production. Under all operating conditions, more than 90% of the biomass was biofilm-associated. Lastly, the present study provides new insights into the performance of continuous-flow bioelectrochemical systems fed with complex waste streams resulting from the pretreatment of lignocellulosic biomass.« less

Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems.

PubMed

Saera-Vila, Alfonso; Kish, Phillip E; Kahana, Alon

2015-08-01

Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (> 37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0-38.3°C, mean ± SD = 38.1°C ± 0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV] = 0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments.

Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems

PubMed Central

Saera-Vila, Alfonso; Kish, Phillip E.

2015-01-01

Abstract Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (>37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0–38.3°C, mean±SD=38.1°C±0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV]=0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments. PMID:25942613

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khan, S. T.; Nagao, Y.; Hiraishi, A., E-mail: hiraishi@ens.tut.ac.jp

Strain NA10B{sup T} and other two strains of the denitrifying betaproteobacterium Diaphorobacter nitroreducens were studied for the performance of solid-phase denitrification (SPD) using poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and some other biodegradable plastics as the source of reducing power in wastewater treatment. Sequencing-batch SPD reactors with these organisms and PHBV granules or flakes as the substrate exhibited good nitrate removal performance. Vial tests using cultures from these parent reactors showed higher nitrate removal rates with PHBV granules (ca. 20 mg-NO{sub 3}{sup −}‐N g{sup −1} [dry wt cells] h{sup −1}) than with PHBV pellets and flakes. In continuous-flow SPD reactors using strain NA10B{sup T}more » and PHBV flakes, nitrate was not detected even at a loading rate of 21 mg-NO{sub 3}{sup −}‐N L{sup −1} h{sup −1}. This corresponded to a nitrate removal rate of 47 mg-NO{sub 3}{sup −}‐N g{sup −1} (dry wt cells) h{sup −1}. In the continuous-flow reactor, the transcription level of the phaZ gene, coding for PHB depolymerase, decreased with time, while that of the nosZ gene, involved in denitrificaiton, was relatively constant. These results suggest that the bioavailability of soluble metabolites as electron donor and carbon sources increases with time in the continuous-flow SPD process, thereby having much higher nitrate removal rates than the process with fresh PHBV as the substrate.« less

Hybrid Continuous-Flow Total Artificial Heart.

PubMed

Fox, Carson; Chopski, Steven; Murad, Nohra; Allaire, Paul; Mentzer, Robert; Rossano, Joseph; Arabia, Francisco; Throckmorton, Amy

2018-05-01

Clinical studies using total artificial hearts (TAHs) have demonstrated that pediatric and adult patients derive quality-of-life benefits from this form of therapy. Two clinically-approved TAHs and other pumps under development, however, have design challenges and limitations, including thromboembolic events, neurologic impairment, infection risk due to large size and percutaneous drivelines, and lack of ambulation, to name a few. To address these limitations, we are developing a hybrid-design, continuous-flow, implantable or extracorporeal, magnetically-levitated TAH for pediatric and adult patients with heart failure. This TAH has only two moving parts: an axial impeller for the pulmonary circulation and a centrifugal impeller for the systemic circulation. This device will utilize the latest generation of magnetic bearing technology. Initial geometries were established using pump design equations, and computational modeling provided insight into pump performance. The designs were the basis for prototype manufacturing and hydraulic testing. The study results demonstrate that the TAH is capable of delivering target blood flow rates of 1-6.5 L/min with pressure rises of 1-92 mm Hg for the pulmonary circulation and 24-150 mm Hg for the systemic circulation at 1500-10 000 rpm. This initial design of the TAH was successful and serves as the foundation to continue its development as a novel, more compact, nonthrombogenic, and effective therapeutic alternative for infants, children, adolescents, and adults with heart failure. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Polyvinylpyrrolidone-based semi-interpenetrating polymer networks as highly selective and chemically stable membranes for all vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Zeng, L.; Zhao, T. S.; Wei, L.; Zeng, Y. K.; Zhang, Z. H.

2016-09-01

Vanadium redox flow batteries (VRFBs) with their high flexibility in configuration and operation, as well as long cycle life are competent for the requirement of future energy storage systems. Nevertheless, due to the application of perfluorinated membranes, VRFBs are plagued by not only the severe migration issue of vanadium ions, but also their high cost. Herein, we fabricate semi-interpenetrating polymer networks (SIPNs), consisting of cross-linked polyvinylpyrrolidone (PVP) and polysulfone (PSF), as alternative membranes for VRFBs. It is demonstrated that the PVP-based SIPNs exhibit extremely low vanadium permeabilities, which contribute to the well-established hydrophilic/hydrophobic microstructures and the Donnan exclusion effect. As a result, the coulombic efficiencies of VRFBs with PVP-based SIPNs reach almost 100% at 40 mA cm-2 to 100 mA cm-2; the energy efficiencies are more than 3% higher than those of VRFBs with Nafion 212. More importantly, the PVP-based SIPNs exhibit a superior chemical stability, as demonstrated both by an ex situ immersion test and continuously cycling test. Hence, all the characterizations and performance tests reported here suggest that PVP-based SIPNs are a promising alternative membrane for redox flow batteries to achieve superior cell performance and excellent cycling stability at the fraction of the cost of perfluorinated membranes.

Turbine flowmeter vs. Fleisch pneumotachometer: a comparative study for exercise testing.

PubMed

Yeh, M P; Adams, T D; Gardner, R M; Yanowitz, F G

1987-09-01

The purpose of this study was to investigate the characteristics of a newly developed turbine flowmeter (Alpha Technologies, model VMM-2) for use in an exercise testing system by comparing its measurement of expiratory flow (VE), O2 uptake (VO2), and CO2 output (VCO2) with the Fleisch pneumotachometer. An IBM PC/AT-based breath-by-breath system was developed, with turbine flowmeter and dual-Fleisch pneumotachometers connected in series. A normal subject was tested twice at rest, 100-W, and 175-W of exercise. Expired gas of 24-32 breaths was collected in a Douglas bag. VE was within 4% accuracy for both flowmeter systems. The Fleisch pneumotachometer system had 5% accuracy for VO2 and VCO2 at rest and exercise. The turbine flowmeter system had up to 20% error for VO2 and VCO2 at rest. Errors decreased as work load increased. Visual observations of the flow curves revealed the turbine signal always lagged the Fleisch signal at the beginning of inspiration or expiration. At the end of inspiration or expiration, the turbine signal continued after the Fleisch signal had returned to zero. The "lag-before-start" and "spin-after-stop" effects of the turbine flowmeter resulted in larger than acceptable error for the VO2 and VCO2 measurements at low flow rates.

High-resolution continuous flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

NASA Astrophysics Data System (ADS)

Emanuelsson, B. D.; Baisden, W. T.; Bertler, N. A. N.; Keller, E. D.; Gkinis, V.

2014-12-01

Here we present an experimental setup for water stable isotopes (δ18O and δD) continuous flow measurements. It is the first continuous flow laser spectroscopy system that is using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research - LGR) in combination with an evaporation unit to continuously analyze sample from an ice core. A Water Vapor Isotopic Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to: (1) increase the temporal resolution by reducing the response time (2) enable measurements on several water standards, and (3) to reduce the influence from memory effects. While this setup was designed for the Continuous Flow Analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. The modified setup provides a shorter response time (~54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the modified setup has a reduced memory effect. Stability tests comparing the modified WVISS and WVISS setups were performed and Allan deviations (σAllan) were calculated to determine precision at different averaging times. For the 2013 modified setup the precision after integration times of 103 s are 0.060 and 0.070‰ for δ18O and δD, respectively. For the WVISS setup the corresponding σAllan values are 0.030, 0.060 and 0.043‰ for δ18O, δD and δ17O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042‰ after 103 s for δ18O, δD and δ17O, respectively. Both the modified setups and WVISS setup are influenced by instrumental drift with δ18O being more drift sensitive than δD. The σAllan values for δ18O of 0.30 and 0.18‰ for the modified (2013) and WVISS setup, respectively after averaging times of 104 s (2.78 h). The Isotopic Water Analyzer (IWA)-modified WVISS setup used during the 2013 Roosevelt Island Climate Evolution (RICE) ice core processing campaign achieved high precision measurements, in particular for δD, with high temporal resolution for the upper part of the core, where a seasonally resolved isotopic signal is preserved.

Hydrodynamic sample injection into short electrophoretic capillary in systems with a flow-gating interface.

PubMed

Opekar, František; Tůma, Petr

2017-01-13

An electrophoretic apparatus with a flow-gating interface has been developed, enabling hydrodynamic sequence injection of the sample into the separation capillary from the liquid flow by underpressure generated in the outlet electrophoretic vessel. The properties of the apparatus were tested on an artificial sample of an equimolar mixture of 100μM potassium and sodium ions and arginine. The repeatability of the injection of the tested ions expressed as RSD (in%) for the peak area, peak height and migration time was in the range 0.76-2.08, 0.18-0.68 and 0.28-0.48, respectively. Under optimum conditions, the apparatus was used for sequence monitoring of the reaction between the antidiabetic drug phenyl biguanide and the glycation agent methyl glyoxal. The reaction solution was continuously sampled by a microdialysis probe from a thermostated external vessel using a syringe pump at a flow rate of 3μLmin -1 and was injected into a separation capillary at certain time intervals. The electrophoretic separation progressed in a capillary with an internal diameter of 50μm with a length of 11.5cm and was monitored using a contactless conductivity detector. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental Investigation of Subsonic Turbulent Boundary Layer Flow Over a Wall-Mounted Axisymmetric Hill

NASA Technical Reports Server (NTRS)

Bell, James H.; Heineck, James T.; Zilliac, Gregory; Mehta, Rabindra D.; Long, Kurtis R.

2016-01-01

An important goal for modern fluid mechanics experiments is to provide datasets which present a challenge for Computational Fluid Dynamics simulations to reproduce. Such "CFD validation experiments" should be well-characterized and well-documented, and should investigate flows which are difficult for CFD to calculate. It is also often convenient for the experiment to be challenging for CFD in some aspects while simple in others. This report is part of the continuing documentation of a series of experiments conducted to characterize the flow around an axisymmetric, modified-cosine-shaped, wall-mounted hill named "FAITH" (Fundamental Aero Investigates The Hill). Computation of this flow is easy in some ways - subsonic flow over a simple shape - while being complex in others - separated flow and boundary layer interactions. The primary set of experiments were performed on a 15.2 cm high, 45.7 cm base diameter machined aluminum model that was tested at mean speeds of 50 m/s (Reynolds Number based on height = 500,000). The ratio of model height to boundary later height was approximately 3. The flow was characterized using surface oil flow visualization, Cobra probe to determine point-wise steady and unsteady 3D velocities, Particle Image Velocimetry (PIV) to determine 3D velocities and turbulence statistics along specified planes, Pressure Sensitive Paint (PSP) to determine mean surface pressures, and Fringe Imaging Skin Friction (FISF) to determine surface skin friction magnitude and direction. A set of pathfinder experiments were also performed in a water channel on a smaller scale (5.1 cm high, 15.2 cm base diameter) sintered nylon model. The water channel test was conducted at a mean test section speed of 3 cm/s (Reynolds Number of 1500), but at the same ratio of model height to boundary layer thickness. Dye injection from both the model and an upstream rake was used to visualize the flow. This report summarizes the experimental set-up, techniques used, and data acquired. It also describes some details of the dataset that is being constructed for use by other researchers, especially the CFD community.

Ignition Characterization Test Results for the LO2/Ethanol Propellant Combination

NASA Technical Reports Server (NTRS)

Popp, Christopher G.; Robinson, Phillip J.; Veith, Eric M.

2006-01-01

A series of contracts were issued by the Marshall Space Flight Center (MSFC) of the National Aeronautics and Space Administration (NASA) under the auspices of the Exploration Systems Mission Directorate to develop and expand the maturity of candidate technologies considered to be important for future space exploration. One such technology was to determine the viability of incorporating non-toxic propellants for Reaction Control Subsystems (RCS). Contract NAS8-01109 was issued to Aerojet to develop a dual thrust Reaction Control Engine (RCE) that utilized liquid oxygen and ethanol as the propellants. The dual thrust RCE incorporated a primary thrust level of 870 lbf, and a vernier thrust level of 10 - 30 lbf. The preferred RCS approach for the dual thrust RCE was to utilize pressure-fed liquid oxygen (LOX) and ethanol propellants; however, previous dual thrust feasibility testing incorporated GOX/Ethanol igniters as opposed to LOX/Ethanol igniters in the design. GOX/Ethanol was easier to ignite, but this combination had system design implications of providing GOX for the igniters. A LOX/Ethanol igniter was desired; however, extensive LOX/Ethanol ignition data over the anticipated operating range for the dual thrust RCE did not exist. Therefore, Aerojet designed and tested a workhorse LOX igniter to determine LOX/Ethanol ignition characteristics as part of a risk mitigation effort for the dual thrust RCE design. LOX, encompassing potential two-phase flow conditions anticipated being present in real mission applications. A workhorse igniter was designed to accommodate the hll LOX design flowrate, as well as a reduced GOX flowrate. It was reasoned that the initial LOX flow through the igniter would flash to GOX due to the latent heat stored in the hardware, causing a reduced oxygen flowrate because of a choked, or sonic, flow condition through the injection elements. As LOX flow continued, the hardware would chill-in, with the injected oxygen flow transitioning from cold GOX through two-phase flow to subcooled LOX. permitted oxygen state points to be determined in the igniter oxidizer manifold, and gas-side igniter chamber thermocouples provided chamber thermal profile characteristics. The cold flow chamber pressure (P(sub c)) for each test was determined and coupled with the igniter chamber diameter (D(sub c)) to calculate the characteristic quench parameter (P(sub c) x D(sub c)), which was plotted as a function of core mixture ratio, m. Ignition limits were determined over a broad range of valve inlet conditions, and ignition was demonstrated with oxygen inlet conditions that ranged from subcooled 210 R LOX to 486 R GOX. Once ignited at cold GOX conditions, combustion was continuous as the hardware chilled in and the core mixture ratio transitioned from values near 1.0 to over 12.5. Pulsing is required in typical RCS engines; therefore, the workhorse igniter was pulse tested to verify the ability to provide the required ignition for a pulsing RCE. The minimum electrical pulse width (EPW) of the dual thrust RCE was 0.080 seconds.

Field continuous measurement of dissolved gases with a CF-MIMS: Applications to the physics and biogeochemistry of groundwater flow

NASA Astrophysics Data System (ADS)

Chatton, Eliot; Labasque, Thierry; de La Bernardie, Jérôme; Guihéneuf, Nicolas; Bour, Olivier; Aquilina, Luc

2017-04-01

In the perspective of a temporal and spatial exploration of aquatic environments (surface and ground water), we developed a technique for precise field continuous measurements of dissolved gases (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe). With a large resolution (from 1×10-9 to 1×10-2 ccSTP/g) and a capability of high frequency analysis (1 measure every 2 seconds), the CF-MIMS (Continuous Flow Membrane Inlet Mass Spectrometer) is an innovative tool allowing the investigation of a large panel of hydrological and biogeochemical processes in aquatic systems. Based on the available MIMS technology, this study introduces the development of the CF-MIMS (conception for field experiments, membrane choices, ionisation) and an original calibration procedure allowing the quantification of mass spectral overlaps and temperature effects on membrane permeability. This study also presents two field applications of the CF-MIMS (Chatton et al, 2016) involving the well-logging of dissolved gases and the implementation of groundwater tracer tests with dissolved 4He. The results demonstrate the analytical capabilities of the CF-MIMS in the field. Therefore, the CF-MIMS is a valuable tool for the field characterisation of biogeochemical reactivity, aquifer transport properties, groundwater recharge, groundwater residence time and aquifer-river exchanges from few hours to several weeks experiments. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.

Integration Test of the High Voltage Hall Accelerator System Components

NASA Technical Reports Server (NTRS)

Kamhawi, Hani; Haag, Thomas; Huang, Wensheng; Pinero, Luis; Peterson, Todd; Dankanich, John

2013-01-01

NASA Glenn Research Center is developing a 4 kilowatt-class Hall propulsion system for implementation in NASA science missions. NASA science mission performance analysis was completed using the latest high voltage Hall accelerator (HiVHAc) and Aerojet-Rocketdyne's state-of-the-art BPT-4000 Hall thruster performance curves. Mission analysis results indicated that the HiVHAc thruster out performs the BPT-4000 thruster for all but one of the missions studied. Tests of the HiVHAc system major components were performed. Performance evaluation of the HiVHAc thruster at NASA Glenn's vacuum facility 5 indicated that thruster performance was lower than performance levels attained during tests in vacuum facility 12 due to the lower background pressures attained during vacuum facility 5 tests when compared to vacuum facility 12. Voltage-Current characterization of the HiVHAc thruster in vacuum facility 5 showed that the HiVHAc thruster can operate stably for a wide range of anode flow rates for discharge voltages between 250 and 600 volts. A Colorado Power Electronics enhanced brassboard power processing unit was tested in vacuum for 1,500 hours and the unit demonstrated discharge module efficiency of 96.3% at 3.9 kilowatts and 650 volts. Stand-alone open and closed loop tests of a VACCO TRL 6 xenon flow control module were also performed. An integrated test of the HiVHAc thruster, brassboard power processing unit, and xenon flow control module was performed and confirmed that integrated operation of the HiVHAc system major components. Future plans include continuing the maturation of the HiVHAc system major components and the performance of a single-string integration test.

Experiments with a Supersonic Multi-Channel Radial Diffuser.

DTIC Science & Technology

1980-09-01

unlimited. 17 . DISTRIBUTION STATEMENT (o the *bsta~c entered nRItok 20, it dffttt Iton, Report) IS. SUPPLEMENTARY NOTES 19. KEY WORDS (Continue o...Improvements 17 VI SIGNIFICANT TEST RESULTS 20 1. General Considerations 20 2. Typical Radial Diffuser Performance 20 3. Flow Stability Experiments 22 VIII...Adjustments Indicated 39 16 Comparison of the Single Channel Performances for Two Extreme Channel Geometries 40 17 Typical Radial Diffuser Performance

A Microwave Driven Ion Source for Continuous-Flow AMS (Abstract)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wills, J.; Schneider, R.J.; Reden, K.F. von

2005-03-15

A microwave-driven, gas-fed ion source originally developed as a high-current positive ion injector for a Tandem accelerator at Chalk River has been the subject of a three-year development program at the Woods Hole Oceanographic Institution NOSAMS facility. Off-line tests have demonstrated positive carbon currents of 1 mA and negative carbon currents of 80 {mu}A from CO2 gas feed. This source and a magnesium charge-exchange canal were coupled to the recombinator of the NOSAMS Tandetron for on-line tests, with the source fed with reference gasses and a combustion device.The promising results obtained have prompted the redesign of the microwave source formore » use as an on-line, continuous-flow injector for a new AMS facility under construction at NOSAMS. The new design is optimized for best transmission of the extracted positive-ion beam through the charge-exchange canal and for reliable operation at 40 kV extraction voltage. Other goals of the re-design include improved lifetime of the microwave window and the elimination of dead volumes in the plasma generator that increase sample hold-up time.This talk will include a summary of results obtained to date at NOSAMS with the Chalk River source and a detailed description of the new design.« less

Performance of a continuous flow ventricular assist device: magnetic bearing design, construction, and testing.

PubMed

Allaire, P; Hilton, E; Baloh, M; Maslen, E; Bearnson, G; Noh, D; Khanwilkar, P; Olsen, D

1998-06-01

A new centrifugal continuous flow ventricular assist device, the CFVAD III, which is fully magnetic bearing suspended, has been developed. It has only one moving part (the impeller), has no contact (magnetic suspension), is compact, and has minimal heating. A centrifugal impeller of 2 inch outer diameter is driven by a permanent magnet brushless DC motor. This paper discusses the design, construction, testing, and performance of the magnetic bearings in the unit. The magnetic suspension consists of an inlet side magnetic bearing and an outlet side magnetic bearing, each divided into 8 pole segments to control axial and radial displacements as well as angular displacements. The magnetic actuators are composed of several different materials to minimize size and weight while having sufficient load capacity to support the forces on the impeller. Flux levels in the range of 0.1 T are employed in the magnetic bearings. Self sensing electronic circuits (without physical sensors) are employed to determine the impellar position and provide the feedback control signal needed for the magnetic bearing control loops. The sensors provide position sensitivity of approximately 0.025 mm. A decentralized 5 axis controller has been developed using modal control techniques. Proportional integral derivative controls are used for each axis to levitate the magnetically supported impeller.

Development of a high power microwave thruster, with a magnetic nozzle, for space applications

NASA Technical Reports Server (NTRS)

Power, John L.; Chapman, Randall A.

1989-01-01

This paper describes the current development of a high-power microwave electrothermal thruster (MET) concept at the NASA Lewis Research Center. Such a thruster would be employed in space for applications such as orbit raining, orbit maneuvering, station change, and possibly trans-lunar or trans-planetary propulsion of spacecraft. The MET concept employs low frequency continuous wave (CW) microwave power to create and continuously pump energy into a flowing propellant gas at relative high pressure via a plasma discharge. The propellant is heated to very high bulk temperatures while passing through the plasma discharge region and then is expanded through a throat-nozzle assembly to produce thrust, as in a conventional rocket engine. Apparatus, which is described, is being assembled at NASA Lewis to test the MET concept to CW power levels of 30 kW at a frequency of 915 MHz. The microwave energy is applied in a resonant cavity applicator and is absorbed by a plasma discharge in the flowing propellant. The ignited plasma acts as a lossy load, and with optimal tuning, energy absorption efficiencies over 95 percent (based on the applied microwave power) are expected. Nitrogen, helium, and hydrogen will be tested as propellants in the MET, at discharge chamber pressures to 10 atm.

Microfluidic magnetic fluidized bed for DNA analysis in continuous flow mode.

PubMed

Hernández-Neuta, Iván; Pereiro, Iago; Ahlford, Annika; Ferraro, Davide; Zhang, Qiongdi; Viovy, Jean-Louis; Descroix, Stéphanie; Nilsson, Mats

2018-04-15

Magnetic solid phase substrates for biomolecule manipulation have become a valuable tool for simplification and automation of molecular biology protocols. However, the handling of magnetic particles inside microfluidic chips for miniaturized assays is often challenging due to inefficient mixing, aggregation, and the advanced instrumentation required for effective actuation. Here, we describe the use of a microfluidic magnetic fluidized bed approach that enables dynamic, highly efficient and simplified magnetic bead actuation for DNA analysis in a continuous flow platform with minimal technical requirements. We evaluate the performance of this approach by testing the efficiency of individual steps of a DNA assay based on padlock probes and rolling circle amplification. This assay comprises common nucleic acid analysis principles, such as hybridization, ligation, amplification and restriction digestion. We obtained efficiencies of up to 90% for these reactions with high throughput processing up to 120μL of DNA dilution at flow rates ranging from 1 to 5μL/min without compromising performance. The fluidized bed was 20-50% more efficient than a commercially available solution for microfluidic manipulation of magnetic beads. Moreover, to demonstrate the potential of this approach for integration into micro-total analysis systems, we optimized the production of a low-cost polymer based microarray and tested its analytical performance for integrated single-molecule digital read-out. Finally, we provide the proof-of-concept for a single-chamber microfluidic chip that combines the fluidized bed with the polymer microarray for a highly simplified and integrated magnetic bead-based DNA analyzer, with potential applications in diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Laser manipulation of atomic and molecular flows

NASA Astrophysics Data System (ADS)

Lilly, Taylor C.

The continuing advance of laser technology enables a range of broadly applicable, laser-based flow manipulation techniques. The characteristics of these laser-based flow manipulations suggest that they may augment, or be superior to, such traditional electro-mechanical methods as ionic flow control, shock tubes, and small scale wind tunnels. In this study, methodology was developed for investigating laser flow manipulation techniques, and testing their feasibility for a number of aerospace, basic physics, and micro technology applications. Theories for laser-atom and laser-molecule interactions have been under development since the advent of laser technology. The theories have yet to be adequately integrated into kinetic flow solvers. Realizing this integration would greatly enhance the scaling of laser-species interactions beyond the realm of ultra-cold atomic physics. This goal was realized in the present study. A representative numerical investigation, of laser-based neutral atomic and molecular flow manipulations, was conducted using near-resonant and non-resonant laser fields. To simulate the laser interactions over a range of laser and flow conditions, the following tools were employed: a custom collisionless gas particle trajectory code and a specifically modified version of the Direct Simulation Monte Carlo statistical kinetic solver known as SMILE. In addition to the numerical investigations, a validating experiment was conducted. The experimental results showed good agreement with the numerical simulations when experimental parameters, such as finite laser line width, were taken into account. Several areas of interest were addressed: laser induced neutral flow steering, collimation, direct flow acceleration, and neutral gas heating. Near-resonant continuous wave laser, and non-resonant pulsed laser, interactions with cesium and nitrogen were simulated. These simulations showed trends and some limitations associated with these interactions, used for flow steering and collimation. The use of one of these interactions, the induced dipole force, was extended beyond a single Gaussian laser field. The interference patterns associated with counter-propagating laser fields, or "optical lattices," were shown to be capable of both direct species acceleration and gas heating. This study resulted in predictions for a continuous, resonant laser-cesium flow with accelerations of 106 m/s2. For this circumstance, a future straightforward proof of principle experiment has been identified. To demonstrate non-resonant gas heating, a series of pulsed optical lattices were simulated interacting with neutral non-polar species. An optimum time between pulses was identified as a function of the collisional relaxation time. Using the optimum time between pulses, molecular nitrogen simulations showed an increase in gas temperature from 300 K to 2470 K at 1 atm, for 50 successive optical lattice pulses. A second proof of principle experiment was identified for future investigation.

Post-explant visualization of thrombi in outflow grafts and their junction to a continuous-flow total artificial heart using a high-definition miniaturized camera.

PubMed

Karimov, Jamshid H; Horvath, David; Sunagawa, Gengo; Byram, Nicole; Moazami, Nader; Golding, Leonard A R; Fukamachi, Kiyotaka

2015-12-01

Post-explant evaluation of the continuous-flow total artificial heart in preclinical studies can be extremely challenging because of the device's unique architecture. Determining the exact location of tissue regeneration, neointima formation, and thrombus is particularly important. In this report, we describe our first successful experience with visualizing the Cleveland Clinic continuous-flow total artificial heart using a custom-made high-definition miniature camera.

Using CONFIG for Simulation of Operation of Water Recovery Subsystems for Advanced Control Software Evaluation

NASA Technical Reports Server (NTRS)

Malin, Jane T.; Flores, Luis; Fleming, Land; Throop, Daiv

2002-01-01

A hybrid discrete/continuous simulation tool, CONFIG, has been developed to support evaluation of the operability life support systems. CON FIG simulates operations scenarios in which flows and pressures change continuously while system reconfigurations occur as discrete events. In simulations, intelligent control software can interact dynamically with hardware system models. CONFIG simulations have been used to evaluate control software and intelligent agents for automating life support systems operations. A CON FIG model of an advanced biological water recovery system has been developed to interact with intelligent control software that is being used in a water system test at NASA Johnson Space Center

Low-flow characteristics of Indiana streams

USGS Publications Warehouse

Stewart, J.A.

1983-01-01

Knowledge of low-flow data for Indiana streams is essential to the planners and developers of water resources for municipal, industrial, and recreational uses in the State. Low-flow data for 219 continuous-record gaging stations through the 1978 water year and for some stations since then are presented in tables and curves. Flow-duration and low-flow-frequency data were estimated or determined for continuous-record stations having more than 10 years of record. In addition, low-flow-frequency data were estimated for 248 partial-record stations. Methods for estimating these data are included in the report. (USGS)

Experimental Investigation of Spatially-Periodic Scalar Patterns in an Inline Mixer

NASA Astrophysics Data System (ADS)

Baskan, Ozge; Speetjens, Michel F. M.; Clercx, Herman J. H.

2015-11-01

Spatially persisting patterns with exponentially decaying intensities form during the downstream evolution of passive scalars in three-dimensional (3D) spatially periodic flows due to the coupled effect of the chaotic nature of the flow and the diffusivity of the material. This has been investigated in many computational and theoretical studies on 3D spatially-periodic flow fields. However, in the limit of zero-diffusivity, the evolution of the scalar fields results in more detailed structures that can only be captured by experiments due to limitations in the computational tools. Our study employs the-state-of-the-art experimental methods to analyze the evolution of 3D advective scalar field in a representative inline mixer, called Quatro static mixer. The experimental setup consists of an optically accessible test section with transparent internal elements, accommodating a pressure-driven pipe flow and equipped with 3D Laser-Induced Fluorescence. The results reveal that the continuous process of stretching and folding of material creates finer structures as the flow progresses, which is an indicator of chaotic advection and the experiments outperform the simulations by revealing far greater level of detail.

Flight survey of the 757 wing noise field and its effects on laminar boundary layer transition. Volume 1: Program description and data analysis

NASA Technical Reports Server (NTRS)

1987-01-01

It was previously observed that an incident acoustic field on a wing with laminar flow can cause transition to turbulent flow if the fluctuating acoustic velocities are of sufficient amplitude and in the critical frequency range for an unstable laminar boundary layer. A section of a wing was modified with a natural laminar flow (NLF) glove to allow direct measurement of the effect of varying engine noise on the extent of laminar flow. The flight test program was completed in June, 1985. At each flight condition, the engine power was varied from about 2600 r/min (idle) to about 4500 r/min (maximum continuous power). The spectral data provides considerable insight into the influences of the various sound sources that contribute to the overall noise levels. Additional analysis will be required to assess the impact of these sources on boundary layer transition. These results demonstrate that substantial laminar flow on the wing of a transport configuration with wing-mounted engines can be obtained.

In vivo preclinical verification of a multimodal diffuse reflectance and correlation spectroscopy system for sensing tissue perfusion

NASA Astrophysics Data System (ADS)

Pakela, Julia M.; Lee, Seung Yup; Hedrick, Taylor L.; Vishwanath, Karthik; Helton, Michael C.; Chung, Yooree G.; Kolodziejski, Noah J.; Staples, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Christian, James F.; O'Reilly, Jameson; Farkas, Dana; Ward, Brent B.; Feinberg, Stephen E.; Mycek, Mary-Ann

2017-02-01

In reconstructive surgery, impeded blood flow in microvascular free flaps due to a compromise in arterial or venous patency secondary to blood clots or vessel spasms can rapidly result in flap failures. Thus, the ability to detect changes in microvascular free flaps is critical. In this paper, we report progress on in vivo pre-clinical testing of a compact, multimodal, fiber-based diffuse correlation and reflectance spectroscopy system designed to quantitatively monitor tissue perfusion in a porcine model's surgically-grafted free flap. We also describe the device's sensitivity to incremental blood flow changes and discuss the prospects for continuous perfusion monitoring in future clinical translational studies.

An iodine hypersonic wind tunnel for the study of nonequilibrium reacting flows

NASA Technical Reports Server (NTRS)

Pham-Van-diep, G. C.; Muntz, E. P.; Weaver, D. P.; Dewitt, T. G.; Bradley, M. K.; Erwin, D. A.; Kunc, J. A.

1992-01-01

A pilot scale hypersonic wind tunnel operating on pure iodine vapor has been designed and tested. The wind tunnel operates intermittently with a run phase lasting approximately 20 minutes. Successful recirculation of the iodine used during the run phase has been achieved but can be improved. Relevant issues regarding the full scale facility's design and operation, and the use of iodine as a working gas are discussed. Continuous wave laser induced fluorescence was used to monitor number densities within the plume flowfield, while pulsed laser induced fluorescence was used in an initial attempt to measure vibrational energy state population distributions. Preliminary nozzle flow calculations based on finite rate chemistry are presented.

Ethyl acetate as an acyl donor in the continuous flow kinetic resolution of (±)-1-phenylethylamine catalyzed by lipases.

PubMed

de Miranda, Amanda S; Miranda, Leandro S M; de Souza, Rodrigo O M A

2013-05-28

The synthesis of chiral amines is still a challenge for organic synthesis since optically pure amines are of great importance for the pharmaceutical and agrochemical industries. Among all the methodologies developed until now, chemoenzymatic dynamic kinetic resolution has proven to be useful for the preparation of enantioenriched primary chiral amines. In our continuous efforts toward the development of a continuous flow process, herein we report our results on the continuous flow kinetic resolution of (±)-1-phenylethylamine leading to the desired products with high enantiomeric ratios (>200) and short residence times (40 minutes) using ethyl acetate as the acyl donor.

MERIDIONAL FLOW IN THE SOLAR CONVECTION ZONE. II. HELIOSEISMIC INVERSIONS OF GONG DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackiewicz, J.; Serebryanskiy, A.; Kholikov, S., E-mail: jasonj@nmsu.edu

2015-06-01

Meridional flow is thought to play a very important role in the dynamics of the solar convection zone; however, because of its relatively small amplitude, precisely measuring it poses a significant challenge. Here we present a complete time–distance helioseismic analysis of about 2 years of ground-based Global Oscillation Network Group (GONG) Doppler data to retrieve the meridional circulation profile for modest latitudes in an attempt to corroborate results from other studies. We use an empirical correction to the travel times due to an unknown center-to-limb systematic effect. The helioseismic inversion procedure is first tested and reasonably validated on artificial datamore » from a large-scale numerical simulation followed by a test to broadly recover the solar differential rotation found from global seismology. From GONG data, we measure poleward photospheric flows at all latitudes with properties that are comparable with earlier studies and a shallow equatorward flow about 65 Mm beneath the surface, in agreement with recent findings from Helioseismic and Magnetic Imager (HMI) data. No strong evidence of multiple circulation cells in depth or latitude is found, yet the whole phase space has not yet been explored. Tests of mass flux conservation are then carried out on the inferred GONG and HMI flows and compared to a fiducial numerical baseline from models, and we find that the continuity equation is poorly satisfied. While the two disparate data sets do give similar results for about the outer 15% of the interior radius, the total inverted circulation pattern appears to be unphysical in terms of mass conservation when interpreted over modest time scales. We can likely attribute this to both the influence of realization noise and subtle effects in the data and measurement procedure.« less

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, Hg, and flow rate.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Standard missing data procedures for... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2, NOX, Hg, and flow rate. (a) Following initial...

40 CFR 75.33 - Standard missing data procedures for SO2, NOX, and flow rate.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Standard missing data procedures for... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.33 Standard missing data procedures for SO2, NOX, and flow rate. (a) Following initial certification...